Search results for: potential pathogens
1023 The Temporal Implications of Spatial Prospects
Authors: Zhuo Job Chen, Kevin Nute
Abstract:
The work reported examines potential linkages between spatial and temporal prospects, and more specifically, between variations in the spatial depth and foreground obstruction of window views, and observers’ sense of connection to the future. It was found that external views from indoor spaces were strongly associated with a sense of the future, that partially obstructing such a view with foreground objects significantly reduced its association with the future, and replacing it with a pictorial representation of the same scene (with no real actual depth) removed most of its temporal association. A lesser change in the spatial depth of the view, however, had no apparent effect on association with the future. While the role of spatial depth has still to be confirmed, the results suggest that spatial prospects directly affect temporal ones. The word “prospect” typifies the overlapping of the spatial and temporal in most human languages. It originated in classical times as a purely spatial term, but in the 16th century took on the additional temporal implication of an imagined view ahead, of the future. The psychological notion of prospection, then, has its distant origins in a spatial analogue. While it is not yet proven that space directly structures our processing of time at a physiological level, it is generally agreed that it commonly does so conceptually. The mental representation of possible futures has been a central part of human survival as a species (Boyer, 2008; Suddendorf & Corballis, 2007). A sense of the future seems critical not only practically, but also psychologically. It has been suggested, for example, that lack of a positive image of the future may be an important contributing cause of depression (Beck, 1974; Seligman, 2016). Most people in the developed world now spend more than 90% of their lives indoors. So any direct link between external views and temporal prospects could have important implications for both human well-being and building design. We found that the ability to see what lies in front of us spatially was strongly associated with a sense of what lies ahead temporally. Partial obstruction of a view was found to significantly reduce that sense connection to the future. Replacing a view with a flat pictorial representation of the same scene removed almost all of its connection with the future, but changing the spatial depth of a real view appeared to have no significant effect. While foreground obstructions were found to reduce subjects’ sense of connection to the future, they increased their sense of refuge and security. Consistent with Prospect and Refuge theory, an ideal environment, then, would seem to be one in which we can “see without being seen” (Lorenz, 1952), specifically one that conceals us frontally from others, without restricting our own view. It is suggested that these optimal conditions might be translated architecturally as screens, the apertures of which are large enough for a building occupant to see through unobstructed from close by, but small enough to conceal them from the view of someone looking from a distance outside.Keywords: foreground obstructions, prospection, spatial depth, window views
Procedia PDF Downloads 1141022 Accumulated Gender-Diverse Co-signing Experience, Knowledge Sharing, and Audit Quality
Authors: Anxuan Xie, Chun-Chan Yu
Abstract:
Survey evidence provides support that auditors can gain professional knowledge not only from client firms but also from teammates they work with. Furthermore, given that knowledge is accumulated in nature, along with the reality that auditors today must work in an environment of increased diversity, whether the attributes of teammates will influence the effects of knowledge sharing and accumulation and ultimately influence an audit partner’s audit quality should be interesting research issues. We test whether the gender of co-signers will moderate the effect of a lead partner’s cooperative experiences on financial restatements. Furthermore, if the answer is “yes”, we further investigate the underlying reasons. We use data from Taiwan because, according to Taiwan’s law, engagement partners, who are basically two certificate public accountants from the same audit firm, are required to disclose (i.e., sign) their names in the audit report of public companies since 1983. Therefore, we can trace each engagement partner’s historic direct cooperative (co-signing) records and get large-sample data. We find that the benefits of knowledge sharing manifest primarily via co-signing audit reports with audit partners of different gender from the lead engagement partners, supporting the argument that in an audit setting, accumulated gender-diverse working relationship is positively associated with knowledge sharing, and therefore improve lead engagements’ audit quality. This study contributes to the extant literature in the following ways. First, we provide evidence that in the auditing setting, the experiences accumulated from cooperating with teammates of a different gender from the lead partner can improve audit quality. Given that most studies find evidence of negative effects of surface-level diversity on team performance, the results of this study support the prior literature that the association between diversity and knowledge sharing actually hinges on the context (e.g., organizational culture, task complexity) and “bridge” (a pre-existing commonality among team members that can smooth the process of diversity toward favorable results) among diversity team members. Second, this study also provides practical insights with respect to the audit firms’ policy of knowledge sharing and deployment of engagement partners. For example, for audit firms that appreciate the merits of knowledge sharing, the deployment of auditors of different gender within an audit team can help auditors accumulate audit-related knowledge, which will further benefit the future performance of those audit firms. Moreover, nowadays, client firms also attach importance to the diversity of their engagement partners. As their policy goals, lawmakers and regulators also continue to promote a gender-diverse working environment. The findings of this study indicate that for audit firms, gender diversity will not be just a means to cater to those groups. Third, for audit committees or other stakeholders, they can evaluate the quality of existing (or potential) lead partners by tracking their co-signing experiences, especially whether they have gender-diverse co-signing experiences.Keywords: co-signing experiences, audit quality, knowledge sharing, gender diversity
Procedia PDF Downloads 721021 In-Situ Formation of Particle Reinforced Aluminium Matrix Composites by Laser Powder Bed Fusion of Fe₂O₃/AlSi12 Powder Mixture Using Consecutive Laser Melting+Remelting Strategy
Authors: Qimin Shi, Yi Sun, Constantinus Politis, Shoufeng Yang
Abstract:
In-situ preparation of particle-reinforced aluminium matrix composites (PRAMCs) by laser powder bed fusion (LPBF) additive manufacturing is a promising strategy to strengthen traditional Al-based alloys. The laser-driven thermite reaction can be a practical mechanism to in-situ synthesize PRAMCs. However, introducing oxygen elements through adding Fe₂O₃ makes the powder mixture highly sensitive to form porosity and Al₂O₃ film during LPBF, bringing challenges to producing dense Al-based materials. Therefore, this work develops a processing strategy combined with consecutive high-energy laser melting scanning and low-energy laser remelting scanning to prepare PRAMCs from a Fe₂O₃/AlSi12 powder mixture. The powder mixture consists of 5 wt% Fe₂O₃ and the remainder AlSi12 powder. The addition of 5 wt% Fe₂O₃ aims to achieve balanced strength and ductility. A high relative density (98.2 ± 0.55 %) was successfully obtained by optimizing laser melting (Emelting) and laser remelting surface energy density (Eremelting) to Emelting = 35 J/mm² and Eremelting = 5 J/mm². Results further reveal the necessity of increasing Emelting, to improve metal liquid’s spreading/wetting by breaking up the Al₂O₃ films surrounding the molten pools; however, the high-energy laser melting produced much porosity, including H₂₋, O₂₋ and keyhole-induced pores. The subsequent low-energy laser remelting could close the resulting internal pores, backfill open gaps and smoothen solidified surfaces. As a result, the material was densified by repeating laser melting and laser remelting layer by layer. Although with two-times laser scanning, the microstructure still shows fine cellular Si networks with Al grains inside (grain size of about 370 nm) and in-situ nano-precipitates (Al₂O₃, Si, and Al-Fe(-Si) intermetallics). Finally, the fine microstructure, nano-structured dispersion strengthening, and high-level densification strengthened the in-situ PRAMCs, reaching yield strength of 426 ± 4 MPa and tensile strength of 473 ± 6 MPa. Furthermore, the results can expect to provide valuable information to process other powder mixtures with severe porosity/oxide-film formation potential, considering the evidenced contribution of laser melting/remelting strategy to densify material and obtain good mechanical properties during LPBF.Keywords: densification, laser powder bed fusion, metal matrix composites, microstructures, mechanical properties
Procedia PDF Downloads 1471020 Features of Composites Application in Shipbuilding
Authors: Valerii Levshakov, Olga Fedorova
Abstract:
Specific features of ship structures, made from composites, i.e. simultaneous shaping of material and structure, large sizes, complicated outlines and tapered thickness have defined leading role of technology, integrating test results from material science, designing and structural analysis. Main procedures of composite shipbuilding are contact molding, vacuum molding and winding. Now, the most demanded composite shipbuilding technology is the manufacture of structures from fiberglass and multilayer hybrid composites by means of vacuum molding. This technology enables the manufacture of products with improved strength properties (in comparison with contact molding), reduction of production duration, weight and secures better environmental conditions in production area. Mechanized winding is applied for the manufacture of parts, shaped as rotary bodies – i.e. parts of ship, oil and other pipelines, deep-submergence vehicles hulls, bottles, reservoirs and other structures. This procedure involves processing of reinforcing fiberglass, carbon and polyaramide fibers. Polyaramide fibers have tensile strength of 5000 MPa, elastic modulus value of 130 MPa and rigidity of the same can be compared with rigidity of fiberglass, however, the weight of polyaramide fiber is 30% less than weight of fiberglass. The same enables to the manufacture different structures, including that, using both – fiberglass and organic composites. Organic composites are widely used for the manufacture of parts with size and weight limitations. High price of polyaramide fiber restricts the use of organic composites. Perspective area of winding technology development is the manufacture of carbon fiber shafts and couplings for ships. JSC ‘Shipbuilding & Shiprepair Technology Center’ (JSC SSTC) developed technology of dielectric uncouplers for cryogenic lines, cooled by gaseous or liquid cryogenic agents (helium, nitrogen, etc.) for temperature range 4.2-300 K and pressure up to 30 MPa – the same is used for separating components of electro physical equipment with different electrical potentials. Dielectric uncouplers were developed, the manufactured and tested in accordance with International Thermonuclear Experimental Reactor (ITER) Technical specification. Spiral uncouplers withstand operating voltage of 30 kV, direct-flow uncoupler – 4 kV. Application of spiral channel instead of rectilinear enables increasing of breakdown potential and reduction of uncouplers sizes. 95 uncouplers were successfully the manufactured and tested. At the present time, Russian the manufacturers of ship composite structures have started absorption of technology of manufacturing the same using automated prepreg laminating; this technology enables the manufacture of structures with improved operational specifications.Keywords: fiberglass, infusion, polymeric composites, winding
Procedia PDF Downloads 2311019 Port Miami in the Caribbean and Mesoamerica: Data, Spatial Networks and Trends
Authors: Richard Grant, Landolf Rhode-Barbarigos, Shouraseni Sen Roy, Lucas Brittan, Change Li, Aiden Rowe
Abstract:
Ports are critical for the US economy, connecting farmers, manufacturers, retailers, consumers and an array of transport and storage operators. Port facilities vary widely in terms of their productivity, footprint, specializations, and governance. In this context, Port Miami is considered as one of the busiest ports providing both cargo and cruise services in connecting the wider region of the Caribbean and Mesoamerica to the global networks. It is considered as the “Cruise Capital of the World and Global Gateway of the Americas” and “leading container port in Florida.” Furthermore, it has also been ranked as one of the top container ports in the world and the second most efficient port in North America. In this regard, Port Miami has made significant investments in the strategic and capital infrastructure of about US$1 billion, including increasing the channel depth and other onshore infrastructural enhancements. Therefore, this study involves a detailed analysis of Port Miami’s network, using publicly available multiple years of data about marine vessel traffic, cargo, and connectivity and performance indices from 2015-2021. Through the analysis of cargo and cruise vessels to and from Port Miami and its relative performance at the global scale from 2015 to 2021, this study examines the port’s long-term resilience and future growth potential. The main results of the analyses indicate that the top category for both inbound and outbound cargo is manufactured products and textiles. In addition, there are a lot of fresh fruits, vegetables, and produce for inbound and processed food for outbound cargo. Furthermore, the top ten port connections for Port Miami are all located in the Caribbean region, the Gulf of Mexico, and the Southeast USA. About half of the inbound cargo comes from Savannah, Saint Thomas, and Puerto Plata, while outbound cargo is from Puerto Corte, Freeport, and Kingston. Additionally, for cruise vessels, a significantly large number of vessels originate from Nassau, followed by Freeport. The number of passenger's vessels pre-COVID was almost 1,000 per year, which dropped substantially in 2020 and 2021 to around 300 vessels. Finally, the resilience and competitiveness of Port Miami were also assessed in terms of its network connectivity by examining the inbound and outbound maritime vessel traffic. It is noteworthy that the most frequent port connections for Port Miami were Freeport and Savannah, followed by Kingston, Nassau, and New Orleans. However, several of these ports, Puerto Corte, Veracruz, Puerto Plata, and Santo Thomas, have low resilience and are highly vulnerable, which needs to be taken into consideration for the long-term resilience of Port Miami in the future.Keywords: port, Miami, network, cargo, cruise
Procedia PDF Downloads 741018 Cycle-Oriented Building Components and Constructions Made from Paper Materials
Authors: Rebecca Bach, Evgenia Kanli, Nihat Kiziltoprak, Linda Hildebrand, Ulrich Knaack, Jens Schneider
Abstract:
The building industry has a high demand for resources and at the same time is responsible for a significant amount of waste created worldwide. Today's building components need to contribute to the protection of natural resources without creating waste. This is defined in the product development phase and impacts the product’s degree of being cycle-oriented. Paper-based materials show advantage due to their renewable origin and their ability to incorporate different functions. Besides the ecological aspects like renewable origin and recyclability the main advantages of paper materials are its light-weight but stiff structure, the optimized production processes and good insulation values. The main deficits from building technology’s perspective are the material's vulnerability to humidity and water as well as inflammability. On material level, those problems can be solved by coatings or through material modification. On construction level intelligent setup and layering of a building component can improve and also solve these issues. The target of the present work is to provide an overview of developed building components and construction typologies mainly made from paper materials. The research is structured in four parts: (1) functions and requirements, (2) preselection of paper-based materials, (3) development of building components and (4) evaluation. As part of the research methodology at first the needs of the building sector are analyzed with the aim to define the main areas of application and consequently the requirements. Various paper materials are tested in order to identify to what extent the requirements are satisfied and determine potential optimizations or modifications, also in combination with other construction materials. By making use of the material’s potentials and solving the deficits on material and on construction level, building components and construction typologies are developed. The evaluation and the calculation of the structural mechanics and structural principals will show that different construction typologies can be derived. Profiles like paper tubes can be used at best for skeleton constructions. Massive structures on the other hand can be formed by plate-shaped elements like solid board or honeycomb. For insulation purposes corrugated cardboard or cellulose flakes have the best properties, while layered solid board can be applied to prevent inner condensation. Enhancing these properties by material combinations for instance with mineral coatings functional constructions mainly out of paper materials were developed. In summary paper materials offer a huge variety of possible applications in the building sector. By these studies a general base of knowledge about how to build with paper was developed and is to be reinforced by further research.Keywords: construction typologies, cycle-oriented construction, innovative building material, paper materials, renewable resources
Procedia PDF Downloads 2671017 Mapping Intertidal Changes Using Polarimetry and Interferometry Techniques
Authors: Khalid Omari, Rene Chenier, Enrique Blondel, Ryan Ahola
Abstract:
Northern Canadian coasts have vulnerable and very dynamic intertidal zones with very high tides occurring in several areas. The impact of climate change presents challenges not only for maintaining this biodiversity but also for navigation safety adaptation due to the high sediment mobility in these coastal areas. Thus, frequent mapping of shorelines and intertidal changes is of high importance. To help in quantifying the changes in these fragile ecosystems, remote sensing provides practical monitoring tools at local and regional scales. Traditional methods based on high-resolution optical sensors are often used to map intertidal areas by benefiting of the spectral response contrast of intertidal classes in visible, near and mid-infrared bands. Tidal areas are highly reflective in visible bands mainly because of the presence of fine sand deposits. However, getting a cloud-free optical data that coincide with low tides in intertidal zones in northern regions is very difficult. Alternatively, the all-weather capability and daylight-independence of the microwave remote sensing using synthetic aperture radar (SAR) can offer valuable geophysical parameters with a high frequency revisit over intertidal zones. Multi-polarization SAR parameters have been used successfully in mapping intertidal zones using incoherence target decomposition. Moreover, the crustal displacements caused by ocean tide loading may reach several centimeters that can be detected and quantified across differential interferometric synthetic aperture radar (DInSAR). Soil moisture change has a significant impact on both the coherence and the backscatter. For instance, increases in the backscatter intensity associated with low coherence is an indicator for abrupt surface changes. In this research, we present primary results obtained following our investigation of the potential of the fully polarimetric Radarsat-2 data for mapping an inter-tidal zone located on Tasiujaq on the south-west shore of Ungava Bay, Quebec. Using the repeat pass cycle of Radarsat-2, multiple seasonal fine quad (FQ14W) images are acquired over the site between 2016 and 2018. Only 8 images corresponding to low tide conditions are selected and used to build an interferometric stack of data. The observed displacements along the line of sight generated using HH and VV polarization are compared with the changes noticed using the Freeman Durden polarimetric decomposition and Touzi degree of polarization extrema. Results show the consistency of both approaches in their ability to monitor the changes in intertidal zones.Keywords: SAR, degree of polarization, DInSAR, Freeman-Durden, polarimetry, Radarsat-2
Procedia PDF Downloads 1301016 Arthroscopic Superior Capsular Reconstruction Using the Long Head of the Biceps Tendon (LHBT)
Authors: Ho Sy Nam, Tang Ha Nam Anh
Abstract:
Background: Rotator cuff tears are a common problem in the aging population. The prevalence of massive rotator cuff tears varies in some studies from 10% to 40%. Of irreparable rotator cuff tears (IRCTs), which are mostly associated with massive tear size, 79% are estimated to have recurrent tears after surgical repair. Recent studies have shown that superior capsule reconstruction (SCR) in massive rotator cuff tears can be an efficient technique with optimistic clinical scores and preservation of stable glenohumeral stability. Superior capsule reconstruction techniques most commonly use either fascia lata autograft or dermal allograft, both of which have their own benefits and drawbacks (such as the potential for donor site issues, allergic reactions, and high cost). We propose a simple technique for superior capsule reconstruction that involves using the long head of the biceps tendon as a local autograft; therefore, the comorbidities related to graft harvesting are eliminated. The long head of the biceps tendon proximal portion is relocated to the footprint and secured as the SCR, serving to both stabilize the glenohumeral joint and maintain vascular supply to aid healing. Objective: The purpose of this study is to assess the clinical outcomes of patients with large to massive RCTs treated by SCR using LHBT. Materials and methods: A study was performed of consecutive patients with large to massive RCTs who were treated by SCR using LHBT between January 2022 and December 2022. We use one double-loaded suture anchor to secure the long head of the biceps to the middle of the footprint. Two more anchors are used to repair the rotator cuff using a single-row technique, which is placed anteriorly and posteriorly on the lateral side of the previously transposed LHBT. Results: The 3 men and 5 women had an average age of 61.25 years (range 48 to 76 years) at the time of surgery. The average follow-up was 8.2 months (6 to 10 months) after surgery. The average preoperative ASES was 45.8, and the average postoperative ASES was 85.83. The average postoperative UCLA score was 29.12. VAS score was improved from 5.9 to 1.12. The mean preoperative ROM of forward flexion and external rotation of the shoulder was 720 ± 160 and 280 ± 80, respectively. The mean postoperative ROM of forward flexion and external rotation were 1310 ± 220 and 630 ± 60, respectively. There were no cases of progression of osteoarthritis or rotator cuff muscle atrophy. Conclusion: SCR using LHBT is considered a treatment option for patients with large or massive RC tears. It can restore superior glenohumeral stability and function of the shoulder joint and can be an effective procedure for selected patients, helping to avoid progression to cuff tear arthropathy.Keywords: superior capsule reconstruction, large or massive rotator cuff tears, the long head of the biceps, stabilize the glenohumeral joint
Procedia PDF Downloads 691015 Slope Stability and Landslides Hazard Analysis, Limitations of Existing Approaches, and a New Direction
Authors: Alisawi Alaa T., Collins P. E. F.
Abstract:
The analysis and evaluation of slope stability and landslide hazards are landslide hazards are critically important in civil engineering projects and broader considerations of safety. The level of slope stability risk should be identified due to its significant and direct financial and safety effects. Slope stability hazard analysis is performed considering static and/or dynamic loading circumstances. To reduce and/or prevent the failure hazard caused by landslides, a sophisticated and practical hazard analysis method using advanced constitutive modeling should be developed and linked to an effective solution that corresponds to the specific type of slope stability and landslides failure risk. Previous studies on slope stability analysis methods identify the failure mechanism and its corresponding solution. The commonly used approaches include used approaches include limit equilibrium methods, empirical approaches for rock slopes (e.g., slope mass rating and Q-slope), finite element or finite difference methods, and district element codes. This study presents an overview and evaluation of these analysis techniques. Contemporary source materials are used to examine these various methods on the basis of hypotheses, the factor of safety estimation, soil types, load conditions, and analysis conditions and limitations. Limit equilibrium methods play a key role in assessing the level of slope stability hazard. The slope stability safety level can be defined by identifying the equilibrium of the shear stress and shear strength. The slope is considered stable when the movement resistance forces are greater than those that drive the movement with a factor of safety (ratio of the resistance of the resistance of the driving forces) that is greater than 1.00. However, popular and practical methods, including limit equilibrium approaches, are not effective when the slope experiences complex failure mechanisms, such as progressive failure, liquefaction, internal deformation, or creep. The present study represents the first episode of an ongoing project that involves the identification of the types of landslides hazards, assessment of the level of slope stability hazard, development of a sophisticated and practical hazard analysis method, linkage of the failure type of specific landslides conditions to the appropriate solution and application of an advanced computational method for mapping the slope stability properties in the United Kingdom, and elsewhere through geographical information system (GIS) and inverse distance weighted spatial interpolation(IDW) technique. This study investigates and assesses the different assesses the different analysis and solution techniques to enhance the knowledge on the mechanism of slope stability and landslides hazard analysis and determine the available solutions for each potential landslide failure risk.Keywords: slope stability, finite element analysis, hazard analysis, landslides hazard
Procedia PDF Downloads 891014 Polymer Nanocomposite Containing Silver Nanoparticles for Wound Healing
Authors: Patrícia Severino, Luciana Nalone, Daniele Martins, Marco Chaud, Classius Ferreira, Cristiane Bani, Ricardo Albuquerque
Abstract:
Hydrogels produced with polymers have been used in the development of dressings for wound treatment and tissue revitalization. Our study on polymer nanocomposites containing silver nanoparticles shows antimicrobial activity and applications in wound healing. The effects are linked with the slow oxidation and Ag⁺ liberation to the biological environment. Furthermore, bacterial cell membrane penetration and metabolic disruption through cell cycle disarrangement also contribute to microbial cell death. The silver antimicrobial activity has been known for many years, and previous reports show that low silver concentrations are safe for human use. This work aims to develop a hydrogel using natural polymers (sodium alginate and gelatin) combined with silver nanoparticles for wound healing and with antimicrobial properties in cutaneous lesions. The hydrogel development utilized different sodium alginate and gelatin proportions (20:80, 50:50 and 80:20). The silver nanoparticles incorporation was evaluated at the concentrations of 1.0, 2.0 and 4.0 mM. The physico-chemical properties of the formulation were evaluated using ultraviolet-visible (UV-Vis) absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The morphological characterization was made using transmission electron microscopy (TEM). Human fibroblast (L2929) viability assay was performed with a minimum inhibitory concentration (MIC) assessment as well as an in vivo cicatrizant test. The results suggested that sodium alginate and gelatin in the (80:20) proportion with 4 mM of AgNO₃ in the (UV-Vis) exhibited a better hydrogel formulation. The nanoparticle absorption spectra of this analysis showed a maximum band around 430 - 450 nm, which suggests a spheroidal form. The TG curve exhibited two weight loss events. DSC indicated one endothermic peak at 230-250 °C, due to sample fusion. The polymers acted as stabilizers of a nanoparticle, defining their size and shape. Human fibroblast viability assay L929 gave 105 % cell viability with a negative control, while gelatin presented 96% viability, alginate: gelatin (80:20) 96.66 %, and alginate 100.33 % viability. The sodium alginate:gelatin (80:20) exhibited significant antimicrobial activity, with minimal bacterial growth at a ratio of 1.06 mg.mL⁻¹ in Pseudomonas aeruginosa and 0.53 mg.mL⁻¹ in Staphylococcus aureus. The in vivo results showed a significant reduction in wound surface area. On the seventh day, the hydrogel-nanoparticle formulation reduced the total area of injury by 81.14 %, while control reached a 45.66 % reduction. The results suggest that silver-hydrogel nanoformulation exhibits potential for wound dressing therapeutics.Keywords: nanocomposite, wound healing, hydrogel, silver nanoparticle
Procedia PDF Downloads 941013 Stability Study of Hydrogel Based on Sodium Alginate/Poly (Vinyl Alcohol) with Aloe Vera Extract for Wound Dressing Application
Authors: Klaudia Pluta, Katarzyna Bialik-Wąs, Dagmara Malina, Mateusz Barczewski
Abstract:
Hydrogel networks, due to their unique properties, are highly attractive materials for wound dressing. The three-dimensional structure of hydrogels provides tissues with optimal moisture, which supports the wound healing process. Moreover, a characteristic feature of hydrogels is their absorption properties which allow for the absorption of wound exudates. For the fabrication of biomedical hydrogels, a combination of natural polymers ensuring biocompatibility and synthetic ones that provide adequate mechanical strength are often used. Sodium alginate (SA) is one of the polymers widely used in wound dressing materials because it exhibits excellent biocompatibility and biodegradability. However, due to poor strength properties, often alginate-based hydrogel materials are enhanced by the addition of another polymer such as poly(vinyl alcohol) (PVA). This paper is concentrated on the preparation methods of sodium alginate/polyvinyl alcohol hydrogel system incorporating Aloe vera extract and glycerin for wound healing material with particular focus on the role of their composition on structure, thermal properties, and stability. Briefly, the hydrogel preparation is based on the chemical cross-linking method using poly(ethylene glycol) diacrylate (PEGDA, Mn = 700 g/mol) as a crosslinking agent and ammonium persulfate as an initiator. In vitro degradation tests of SA/PVA/AV hydrogels were carried out in Phosphate-Buffered Saline (pH – 7.4) as well as in distilled water. Hydrogel samples were firstly cut into half-gram pieces (in triplicate) and immersed in immersion fluid. Then, all specimens were incubated at 37°C and then the pH and conductivity values were measurements at time intervals. The post-incubation fluids were analyzed using SEC/GPC to check the content of oligomers. The separation was carried out at 35°C on a poly(hydroxy methacrylate) column (dimensions 300 x 8 mm). 0.1M NaCl solution, whose flow rate was 0.65 ml/min, was used as the mobile phase. Three injections with a volume of 50 µl were made for each sample. The thermogravimetric data of the prepared hydrogels were collected using a Netzsch TG 209 F1 Libra apparatus. The samples with masses of about 10 mg were weighed separately in Al2O3 crucibles and then were heated from 30°C to 900°C with a scanning rate of 10 °C∙min−1 under a nitrogen atmosphere. Based on the conducted research, a fast and simple method was developed to produce potential wound dressing material containing sodium alginate, poly(vinyl alcohol) and Aloe vera extract. As a result, transparent and flexible SA/PVA/AV hydrogels were obtained. The degradation experiments indicated that most of the samples immersed in PBS as well as in distilled water were not degraded throughout the whole incubation time.Keywords: hydrogels, wound dressings, sodium alginate, poly(vinyl alcohol)
Procedia PDF Downloads 1561012 Sustainable Harvesting, Conservation and Analysis of Genetic Diversity in Polygonatum Verticillatum Linn.
Authors: Anchal Rana
Abstract:
Indian Himalayas with their diverse climatic conditions are home to many rare and endangered medicinal flora. One such species is Polygonatum verticillatum Linn., popularly known as King Solomon’s Seal or Solomon’s Seal. Its mention as an incredible medicinal herb comes from 5000 years ago in Indian Materia Medica as a component of Ashtavarga, a poly-herbal formulation comprising of eight herbs illustrated as world’s first ever revitalizing and rejuvenating nutraceutical food, which is now commercialised in the name ‘Chaywanprash’. It is an erect tall (60 to 120 cm) perennial herb with sessile, linear leaves and white pendulous flowers. The species grows well in an altitude range of 1600 to 3600 m amsl, and propagates mostly through rhizomes. The rhizomes are potential source for significant phytochemicals like flavonoids, phenolics, lectins, terpenoids, allantoin, diosgenin, β-Sitosterol and quinine. The presence of such phytochemicals makes the species an asset for antioxidant, cardiotonic, demulcent, diuretic, energizer, emollient, aphrodisiac, appetizer, glactagogue, etc. properties. Having profound concentrations of macro and micronutrients, species has fine prospects of being used as a diet supplement. However, due to unscientific and gregarious uprooting, it has been assigned a status of ‘vulnerable’ and ‘endangered’ in the Conservation Assessment and Management Plan (CAMP) process conducted by Foundation for Revitalisation of Local Health Traditions (FRLHT) during 2010, according to IUCN Red-List Criteria. Further, destructive harvesting, land use disturbances, heavy livestock grazing, climatic changes and habitat fragmentation have substantially contributed towards anomaly of the species. It, therefore, became imperative to conserve the diversity of the species and make judicious use in future research and commercial programme and schemes. A Gene Bank was therefore established at High Altitude Herbal Garden of the Forest Research Institute, Dehradun, India situated at Chakarata (30042’52.99’’N, 77051’36.77’’E, 2205 m amsl) consisting 149 accessions collected from thirty-one geographical locations spread over three Himalayan States of Jammu and Kashmir, Himachal Pradesh, and Uttarakhand. The present investigations purport towards sampling and collection of divergent germplasm followed by planting and cultivation techniques. The ultimate aim is thereby focussed on analysing genetic diversity of the species and capturing promising genotypes for carrying out further genetic improvement programme so to contribute towards sustainable development and healthcare.Keywords: Polygonatum verticillatum Linn., phytochemicals, genetic diversity, conservation, gene bank
Procedia PDF Downloads 1551011 Synthesis of Functionalized-2-Aryl-2, 3-Dihydroquinoline-4(1H)-Ones via Fries Rearrangement of Azetidin-2-Ones
Authors: Parvesh Singh, Vipan Kumar, Vishu Mehra
Abstract:
Quinoline-4-ones represent an important class of heterocyclic scaffolds that have attracted significant interest due to their various biological and pharmacological activities. This heterocyclic unit also constitutes an integral component in drugs used for the treatment of neurodegenerative diseases, sleep disorders and in antibiotics viz. norfloxacin and ciprofloxacin. The synthetic accessibility and possibility of fictionalization at varied positions in quinoline-4-ones exemplifies an elegant platform for the designing of combinatorial libraries of functionally enriched scaffolds with a range of pharmacological profles. They are also considered to be attractive precursors for the synthesis of medicinally imperative molecules such as non-steroidal androgen receptor antagonists, antimalarial drug Chloroquine and martinellines with antibacterial activity. 2-Aryl-2,3-dihydroquinolin-4(1H)-ones are present in many natural and non-natural compounds and are considered to be the aza-analogs of favanones. The β-lactam class of antibiotics is generally recognized to be a cornerstone of human health care due to the unparalleled clinical efficacy and safety of this type of antibacterial compound. In addition to their biological relevance as potential antibiotics, β-lactams have also acquired a prominent place in organic chemistry as synthons and provide highly efficient routes to a variety of non-protein amino acids, such as oligopeptides, peptidomimetics, nitrogen-heterocycles, as well as biologically active natural and unnatural products of medicinal interest such as indolizidine alkaloids, paclitaxel, docetaxel, taxoids, cyptophycins, lankacidins, etc. A straight forward route toward the synthesis of quinoline-4-ones via the triflic acid assisted Fries rearrangement of N-aryl-βlactams has been reported by Tepe and co-workers. The ring expansion observed in this case was solely attributed to the inherent ring strain in β-lactam ring because -lactam failed to undergo rearrangement under reaction conditions. Theabovementioned protocol has been recently extended by our group for the synthesis of benzo[b]-azocinon-6-ones via a tandem Michael addition–Fries rearrangement of sorbyl anilides as well as for the single-pot synthesis of 2-aryl-quinolin-4(3H)-ones through the Fries rearrangement of 3-dienyl-βlactams. In continuation with our synthetic endeavours with the β-lactam ring and in view of the lack of convenient approaches for the synthesis of C-3 functionalized quinolin-4(1H)-ones, the present work describes the single-pot synthesis of C-3 functionalized quinolin-4(1H)-ones via the trific acid promoted Fries rearrangement of C-3 vinyl/isopropenyl substituted β-lactams. In addition, DFT calculations and MD simulations were performed to investigate the stability profles of synthetic compounds.Keywords: dihydroquinoline, fries rearrangement, azetidin-2-ones, quinoline-4-ones
Procedia PDF Downloads 2421010 Determinants of Quality of Life in Patients with Atypical Prarkinsonian Syndromes: 1-Year Follow-Up Study
Authors: Tatjana Pekmezovic, Milica Jecmenica-Lukic, Igor Petrovic, Vladimir Kostic
Abstract:
Background: A group of atypical parkinsonian syndromes (APS) includes a variety of rare neurodegenerative disorders characterized by reduced life expectancy, increasing disability, and considerable impact on health-related quality of life (HRQoL). Aim: In this study we wanted to answer two questions: a) which demographic and clinical factors are main contributors of HRQoL in our cohort of patients with APS, and b) how does quality of life of these patients change over 1-year follow-up period. Patients and Methods: We conducted a prospective cohort study in hospital settings. The initial study comprised all consecutive patients who were referred to the Department of Movement Disorders, Clinic of Neurology, Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade (Serbia), from January 31, 2000 to July 31, 2013, with the initial diagnoses of ‘Parkinson’s disease’, ‘parkinsonism’, ‘atypical parkinsonism’ and ‘parkinsonism plus’ during the first 8 months from the appearance of first symptom(s). The patients were afterwards regularly followed in 4-6 month intervals and eventually the diagnoses were established for 46 patients fulfilling the criteria for clinically probable progressive supranuclear palsy (PSP) and 36 patients for probable multiple system atrophy (MSA). The health-related quality of life was assessed by using the SF-36 questionnaire (Serbian translation). Hierarchical multiple regression analysis was conducted to identify predictors of composite scores of SF-36. The importance of changes in quality of life scores of patients with APS between baseline and follow-up time-point were quantified using Wilcoxon Signed Ranks Test. The magnitude of any differences for the quality of life changes was calculated as an effect size (ES). Results: The final models of hierarchical regression analysis showed that apathy measured by the Apathy evaluation scale (AES) score accounted for 59% of the variance in the Physical Health Composite Score of SF-36 and 14% of the variance in the Mental Health Composite Score of SF-36 (p<0.01). The changes in HRQoL were assessed in 52 patients with APS who completed 1-year follow-up period. The analysis of magnitude for changes in HRQoL during one-year follow-up period have shown sustained medium ES (0.50-0.79) for both Physical and Mental health composite scores, total quality of life as well as for the Physical Health, Vitality, Role Emotional and Social Functioning. Conclusion: This study provides insight into new potential predictors of HRQoL and its changes over time in patients with APS. Additionally, identification of both prognostic markers of a poor HRQoL and magnitude of its changes should be considered when developing comprehensive treatment-related strategies and health care programs aimed at improving HRQoL and well-being in patients with APS.Keywords: atypical parkinsonian syndromes, follow-up study, quality of life, APS
Procedia PDF Downloads 2991009 Teen Insights into Drugs, Alcohol, and Nicotine: A National Survey of Adolescent Attitudes toward Addictive Substances
Authors: Linda Richter
Abstract:
Background and Significance: The influence of parents on their children’s attitudes and behaviors is immense, even as children grow out of what one might assume to be their most impressionable years and into teenagers. This study specifically examines the potential that parents have to prevent or reduce the risk of adolescent substance use, even in the face of considerable environmental influences to use nicotine, alcohol, or drugs. Methodology: The findings presented are based on a nationally representative survey of 1,014 teens aged 12-17 living in the United States. Data were collected using an online platform in early 2018. About half the sample was female (51%), 49% was aged 12-14, and 51% was aged 15-17. The margin of error was +/- 3.5%. Demographic data on the teens and their families were available through the survey platform. Survey items explored adolescent respondents’ exposure to addictive substances; the extent to which their sources of information about these substances are reliable or credible; friends’ and peers’ substance use; their own intentions to try substances in the future; and their relationship with their parents. Key Findings: Exposure to nicotine, alcohol, or other drugs and misinformation about these substances were associated with a greater likelihood that adolescents have friends who use drugs and that they have intentions to try substances in the future, which are known to directly predict actual teen substance use. In addition, teens who reported a positive relationship with their parents and having parents who are involved in their lives had a lower likelihood of having friends who use drugs and of having intentions to try substances in the future. This relationship appears to be mediated by parents’ ability to reduce the extent to which their children are exposed to substances in their environment and to misinformation about them. Indeed, the findings indicated that teens who reported a good relationship with their parents and those who reported higher levels of parental monitoring had significantly higher odds of reporting a lower number of risk factors than teens with a less positive relationship with parents or less monitoring. There also were significantly greater risk factors associated with substance use among older teens relative to younger teens. This shift appears to coincide directly with the tendency of parents to pull back in their monitoring and their involvement in their adolescent children’s lives. Conclusion: The survey findings underscore the importance of resisting the urge to completely pull back as teens age and demand more independence since that is exactly when the risks for teen substance use spike and young people need their parents and other trusted adults to be involved more than ever. Particularly through the cultivation of a healthy, positive, and open relationship, parents can help teens receive accurate and credible information about substance use and also monitor their whereabouts and exposure to addictive substances. These findings, which come directly from teens themselves, demonstrate the importance of continued parental engagement throughout children’s lives, regardless of their age and the disincentives to remaining involved and connected.Keywords: adolescent, parental monitoring, prevention, substance use
Procedia PDF Downloads 1251008 Seed Associated Microbial Communities of Holoparasitic Cistanche Species from Armenia and Portugal
Authors: K. Petrosyan, R. Piwowarczyk, K. Ruraż, S. Thijs, J. Vangronsveld, W. Kaca
Abstract:
Holoparasitic plants are flowering heterotrophic angiosperms which with the help of an absorbing organ - haustorium, attach to another plant, the so-called the host. Due to the different hosts, unusual lifestyle, lack of roots, chlorophylls and photosynthesis, these plants are interesting and unique study objects for global biodiversity. The seeds germination of the parasitic plants also is unique: they germinate only in response to germination stimulants, namely strigolactones produced by the root of an appropriate host. Resistance of the seeds on different environmental conditions allow them to stay viable in the soil for more than 20 years. Among the wide range of plant protection mechanisms the endophytic communities have a specific role. In this way, they have the potential to mitigate the impacts of adverse conditions such as soil salinization. The major objective of our study was to compare the bacterial endo-microbiomes from seeds of two holoparasitic plants from Orobanchaceae family, Cistanche – C. armena (Armenia) and C. phelypaea (Portugal) – from saline habitats different in soil water status. The research aimed to perform how environmental conditions influence on the diversity of the bacterial communities of C. armena and C. phelypaea seeds. This was achieved by comparison of the endophytic microbiomes of two species and isolation of culturable bacteria. A combination of culture-dependent and molecular techniques was employed for the identification of the seed endomicrobiome (culturable and unculturable). Using the V3-V4 hypervariable region of the 16S rRNA gene, four main taxa were identified: Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, but the relative proportion of the taxa was different in each type of seed. Generally, sixteen phyla, 323 genera and 710 bacterial species were identified, mainly Gram negative, halotolerant bacteria with an environmental origin. However, also some unclassified and unexplored taxonomic groups were found in the seeds of both plants. 16S rRNA gene sequencing analysis from both species identified the gram positive, endospore forming, halotolerant and alkaliphile Bacillus spp. which suggests that the endophytic bacteria of examined seeds possess traits that are correlated with the natural habitat of their hosts. The cultivable seed endophytes from C. armena and C. phelypaea were rather similar, notwithstanding the big distances between their growth habitats - Armenia and Portugal. Although the seed endophytic microbiomes of C. armena and C. phelypaea contain a high number of common bacterial taxa, also remarkable differences exist. We demonstrated that the environmental conditions or abiotic stresses influence on diversity of the bacterial communities of holoparasiotic seeds. To the best of our knowledge the research is the first report of endophytes from seeds of holoparasitic Cistanche armena and C. phelypaea plants.Keywords: microbiome, parasitic plant, salinity, seeds
Procedia PDF Downloads 661007 Viability Analysis of a Centralized Hydrogen Generation Plant for Use in Oil Refining Industry
Authors: C. Fúnez Guerra, B. Nieto Calderón, M. Jaén Caparrós, L. Reyes-Bozo, A. Godoy-Faúndez, E. Vyhmeister
Abstract:
The global energy system is experiencing a change of scenery. Unstable energy markets, an increasing focus on climate change and its sustainable development is forcing businesses to pursue new solutions in order to ensure future economic growth. This has led to the interest in using hydrogen as an energy carrier in transportation and industrial applications. As an energy carrier, hydrogen is accessible and holds a high gravimetric energy density. Abundant in hydrocarbons, hydrogen can play an important role in the shift towards low-emission fossil value chains. By combining hydrogen production by natural gas reforming with carbon capture and storage, the overall CO2 emissions are significantly reduced. In addition, the flexibility of hydrogen as an energy storage makes it applicable as a stabilizer in the renewable energy mix. The recent development in hydrogen fuel cells is also raising the expectations for a hydrogen powered transportation sector. Hydrogen value chains exist to a large extent in the industry today. The global hydrogen consumption was approximately 50 million tonnes (7.2 EJ) in 2013, where refineries, ammonia, methanol production and metal processing were main consumers. Natural gas reforming produced 48% of this hydrogen, but without carbon capture and storage (CCS). The total emissions from the production reached 500 million tonnes of CO2, hence alternative production methods with lower emissions will be necessary in future value chains. Hydrogen from electrolysis is used for a wide range of industrial chemical reactions for many years. Possibly, the earliest use was for the production of ammonia-based fertilisers by Norsk Hydro, with a test reactor set up in Notodden, Norway, in 1927. This application also claims one of the world’s largest electrolyser installations, at Sable Chemicals in Zimbabwe. Its array of 28 electrolysers consumes 80 MW per hour, producing around 21,000 Nm3/h of hydrogen. These electrolysers can compete if cheap sources of electricity are available and natural gas for steam reforming is relatively expensive. Because electrolysis of water produces oxygen as a by-product, a system of Autothermal Reforming (ATR) utilizing this oxygen has been analyzed. Replacing the air separation unit with electrolysers produces the required amount of oxygen to the ATR as well as additional hydrogen. The aim of this paper is to evaluate the technical and economic potential of large-scale production of hydrogen for oil refining industry. Sensitivity analysis of parameters such as investment costs, plant operating hours, electricity price and sale price of hydrogen and oxygen are performed.Keywords: autothermal reforming, electrolyser, hydrogen, natural gas, steam methane reforming
Procedia PDF Downloads 2051006 Obtaining Composite Cotton Fabric by Cyclodextrin Grafting
Authors: U. K. Sahin, N. Erdumlu, C. Saricam, I. Gocek, M. H. Arslan, H. Acikgoz-Tufan, B. Kalav
Abstract:
Finishing is an important part of fabric processing with which a wide range of features are imparted to greige or colored fabrics for various end-uses. Especially, by the addition or impartation of nano-scaled particles to the fabric structure composite fabrics, a kind of composite materials can be acquired. Composite materials, generally shortened as composites or in other words composition materials, are engineered or naturally occurring materials made from two or more component materials with significantly different physical, mechanical or chemical characteristics remaining separate and distinctive at the macroscopic or microscopic scale within the end product structure. Therefore, the technique finishing which is one of the fundamental methods to be applied on fabrics for obtainment of composite fabrics with many functionalities was used in the current study with the same purpose. However, regardless of the finishing materials applied, the efficient life of finished product on offering desired feature is low, since the durability of finishes on the material is limited. Any increase in durability of these finishes on textiles would enhance the life of use for textiles, which will result in happier users. Therefore, in this study, since higher durability was desired for the finishing materials fixed on the fabrics, nano-scaled hollow structured cyclodextrins were chemically imparted by grafting to the structure of conventional cotton fabrics by the help of finishing technique in order to be fixed permanently. By this way, a processed and functionalized base fabric having potential to be treated in the subsequent processes with many different finishing agents and nanomaterials could be obtained. Henceforth, this fabric can be used as a multi-functional fabric due to the encapturing ability of cyclodextrins to molecules/particles via physical/chemical means. In this study, scoured and rinsed woven bleached plain weave 100% cotton fabrics were utilized because textiles made of cotton are the most demanded textile products in the textile market by the textile consumers in daily life. Cotton fabric samples were immersed in treating baths containing β-cyclodextrin and 1,2,3,4-butanetetracarboxylic acid and to reduce the curing temperature the catalyst sodium hypophosphite monohydrate was used. All impregnated fabric samples were pre-dried. The reaction of grafting was performed in dry state. The treated and cured fabric samples were rinsed with warm distilled water and dried. The samples were dried for 4 h and weighed before and after finishing and rinsing. Stability and durability of β-cyclodextrins on fabric surface against external factors such as washing as well as strength of functionalized fabric in terms of tensile and tear strength were tested. Presence and homogeneity of distribution of β-cyclodextrins on fabric surface were characterized.Keywords: cotton fabric, cyclodextrine, improved durability, multifunctional composite textile
Procedia PDF Downloads 2871005 Diagnostic Performance of Mean Platelet Volume in the Diagnosis of Acute Myocardial Infarction: A Meta-Analysis
Authors: Kathrina Aseanne Acapulco-Gomez, Shayne Julieane Morales, Tzar Francis Verame
Abstract:
Mean platelet volume (MPV) is the most accurate measure of the size of platelets and is routinely measured by most automated hematological analyzers. Several studies have shown associations between MPV and cardiovascular risks and outcomes. Although its measurement may provide useful data, MPV remains to be a diagnostic tool that is yet to be included in routine clinical decision making. The aim of this systematic review and meta-analysis is to determine summary estimates of the diagnostic accuracy of mean platelet volume for the diagnosis of myocardial infarction among adult patients with angina and/or its equivalents in terms of sensitivity, specificity, diagnostic odds ratio, and likelihood ratios, and to determine the difference of the mean MPV values between those with MI and those in the non-MI controls. The primary search was done through search in electronic databases PubMed, Cochrane Review CENTRAL, HERDIN (Health Research and Development Information Network), Google Scholar, Philippine Journal of Pathology, and Philippine College of Physicians Philippine Journal of Internal Medicine. The reference list of original reports was also searched. Cross-sectional, cohort, and case-control articles studying the diagnostic performance of mean platelet volume in the diagnosis of acute myocardial infarction in adult patients were included in the study. Studies were included if: (1) CBC was taken upon presentation to the ER or upon admission (within 24 hours of symptom onset); (2) myocardial infarction was diagnosed with serum markers, ECG, or according to accepted guidelines by the Cardiology societies (American Heart Association (AHA), American College of Cardiology (ACC), European Society of Cardiology (ESC); and, (3) if outcomes were measured as significant difference AND/OR sensitivity and specificity. The authors independently screened for inclusion of all the identified potential studies as a result of the search. Eligible studies were appraised using well-defined criteria. Any disagreement between the reviewers was resolved through discussion and consensus. The overall mean MPV value of those with MI (9.702 fl; 95% CI 9.07 – 10.33) was higher than in those of the non-MI control group (8.85 fl; 95% CI 8.23 – 9.46). Interpretation of the calculated t-value of 2.0827 showed that there was a significant difference in the mean MPV values of those with MI and those of the non-MI controls. The summary sensitivity (Se) and specificity (Sp) for MPV were 0.66 (95% CI; 0.59 - 0.73) and 0.60 (95% CI; 0.43 – 0.75), respectively. The pooled diagnostic odds ratio (DOR) was 2.92 (95% CI; 1.90 – 4.50). The positive likelihood ratio of MPV in the diagnosis of myocardial infarction was 1.65 (95% CI; 1.20 – 22.27), and the negative likelihood ratio was 0.56 (95% CI; 0.50 – 0.64). The intended role for MPV in the diagnostic pathway of myocardial infarction would perhaps be best as a triage tool. With a DOR of 2.92, MPV values can discriminate between those who have MI and those without. For a patient with angina presenting with elevated MPV values, it is 1.65 times more likely that he has MI. Thus, it is implied that the decision to treat a patient with angina or its equivalents as a case of MI could be supported by an elevated MPV value.Keywords: mean platelet volume, MPV, myocardial infarction, angina, chest pain
Procedia PDF Downloads 741004 RAD-Seq Data Reveals Evidence of Local Adaptation between Upstream and Downstream Populations of Australian Glass Shrimp
Authors: Sharmeen Rahman, Daniel Schmidt, Jane Hughes
Abstract:
Paratya australiensis Kemp (Decapoda: Atyidae) is a widely distributed indigenous freshwater shrimp, highly abundant in eastern Australia. This species has been considered as a model stream organism to study genetics, dispersal, biology, behaviour and evolution in Atyids. Paratya has a filter feeding and scavenging habit which plays a significant role in the formation of lotic community structure. It has been shown to reduce periphyton and sediment from hard substrates of coastal streams and hence acts as a strongly-interacting ecosystem macroconsumer. Besides, Paratya is one of the major food sources for stream dwelling fishes. Paratya australiensis is a cryptic species complex consisting of 9 highly divergent mitochondrial DNA lineages. Among them, one lineage has been observed to favour upstream sites at higher altitudes, with cooler water temperatures. This study aims to identify local adaptation in upstream and downstream populations of this lineage in three streams in the Conondale Range, North-eastern Brisbane, Queensland, Australia. Two populations (up and down stream) from each stream have been chosen to test for local adaptation, and a parallel pattern of adaptation is expected across all streams. Six populations each consisting of 24 individuals were sequenced using the Restriction Site Associated DNA-seq (RAD-seq) technique. Genetic markers (SNPs) were developed using double digest RAD sequencing (ddRAD-seq). These were used for de novo assembly of Paratya genome. De novo assembly was done using the STACKs program and produced 56, 344 loci for 47 individuals from one stream. Among these individuals, 39 individuals shared 5819 loci, and these markers are being used to test for local adaptation using Fst outlier tests (Arlequin) and Bayesian analysis (BayeScan) between up and downstream populations. Fst outlier test detected 27 loci likely to be under selection and the Bayesian analysis also detected 27 loci as under selection. Among these 27 loci, 3 loci showed evidence of selection at a significance level using BayeScan program. On the other hand, up and downstream populations are strongly diverged at neutral loci with a Fst =0.37. Similar analysis will be done with all six populations to determine if there is a parallel pattern of adaptation across all streams. Furthermore, multi-locus among population covariance analysis will be done to identify potential markers under selection as well as to compare single locus versus multi-locus approaches for detecting local adaptation. Adaptive genes identified in this study can be used for future studies to design primers and test for adaptation in related crustacean species.Keywords: Paratya australiensis, rainforest streams, selection, single nucleotide polymorphism (SNPs)
Procedia PDF Downloads 2441003 Assessment of Surface Water Quality near Landfill Sites Using a Water Pollution Index
Authors: Alejandro Cittadino, David Allende
Abstract:
Landfilling of municipal solid waste is a common waste management practice in Argentina as in many parts of the world. There is extensive scientific literature on the potential negative effects of landfill leachates on the environment, so it’s necessary to be rigorous with the control and monitoring systems. Due to the specific municipal solid waste composition in Argentina, local landfill leachates contain large amounts of organic matter (biodegradable, but also refractory to biodegradation), as well as ammonia-nitrogen, small trace of some heavy metals, and inorganic salts. In order to investigate the surface water quality in the Reconquista river adjacent to the Norte III landfill, water samples both upstream and downstream the dumpsite are quarterly collected and analyzed for 43 parameters including organic matter, heavy metals, and inorganic salts, as required by the local standards. The objective of this study is to apply a water quality index that considers the leachate characteristics in order to determine the quality status of the watercourse through the landfill. The water pollution index method has been widely used in water quality assessments, particularly rivers, and it has played an increasingly important role in water resource management, since it provides a number simple enough for the public to understand, that states the overall water quality at a certain location and time. The chosen water quality index (ICA) is based on the values of six parameters: dissolved oxygen (in mg/l and percent saturation), temperature, biochemical oxygen demand (BOD5), ammonia-nitrogen and chloride (Cl-) concentration. The index 'ICA' was determined both upstream and downstream the Reconquista river, being the rating scale between 0 (very poor water quality) and 10 (excellent water quality). The monitoring results indicated that the water quality was unaffected by possible leachate runoff since the index scores upstream and downstream were ranked in the same category, although in general, most of the samples were classified as having poor water quality according to the index’s scale. The annual averaged ICA index scores (computed quarterly) were 4.9, 3.9, 4.4 and 5.0 upstream and 3.9, 5.0, 5.1 and 5.0 downstream the river during the study period between 2014 and 2017. Additionally, the water quality seemed to exhibit distinct seasonal variations, probably due to annual precipitation patterns in the study area. The ICA water quality index appears to be appropriate to evaluate landfill impacts since it accounts mainly for organic pollution and inorganic salts and the absence of heavy metals in the local leachate composition, however, the inclusion of other parameters could be more decisive in discerning the affected stream reaches from the landfill activities. A future work may consider adding to the index other parameters like total organic carbon (TOC) and total suspended solids (TSS) since they are present in the leachate in high concentrations.Keywords: landfill, leachate, surface water, water quality index
Procedia PDF Downloads 1401002 The Use of Brachytherapy in the Treatment of Liver Metastases: A Systematic Review
Authors: Mateusz Bilski, Jakub Klas, Emilia Kowalczyk, Sylwia Koziej, Katarzyna Kulszo, Ludmiła Grzybowska- Szatkowska
Abstract:
Background: Liver metastases are a common complication of primary solid tumors and sig-nificantly reduce patient survival. In the era of increasing diagnosis of oligometastatic disease and oligoprogression, methods of local treatment of metastases, i.e. MDT, are becoming more important. Implementation of such treatment can be considered for liver metastases, which are a common complication of primary solid tumors and significantly reduce patient survival. To date, the mainstay of treatment for oligometastatic disease has been surgical resection, but not all patients qualify for the procedure. As an alternative to surgical resection, radiotherapy techniques have become available, including stereotactic body radiation therapy (SBRT) or high-dose interstitial brachytherapy (iBT). iBT is an invasive method that emits very high doses of radiation from the inside of the tumor to the outside. This technique provides better tumor coverage than SBRT while having little impact on surrounding healthy tissue and elim-inates some concerns involving respiratory motion. Methods: We conducted a systematic re-view of the scientific literature on the use of brachytherapy in the treatment of liver metasta-ses from 2018 - 2023 using PubMed and ResearchGate browsers according to PRISMA rules. Results: From 111 articles, 18 publications containing information on 729 patients with liver metastases were selected. iBT has been shown to provide high rates of tumor control. Among 14 patients with 54 unresectable RCC liver metastases, after iBT LTC was 92.6% during a median follow-up of 10.2 months, PFS was 3.4 months. In analysis of 167 patients after treatment with a single fractional dose of 15-25 Gy with brachytherapy at 6- and 12-month follow-up, LRFS rates of 88,4-88.7% and 70.7 - 71,5%, PFS of 78.1 and 53.8%, and OS of 92.3 - 96.7% and 76,3% - 79.6%, respectively, were achieved. No serious complications were observed in all patients. Distant intrahepatic progression occurred later in patients with unre-sectable liver metastases after brachytherapy (PFS: 19.80 months) than in HCC patients (PFS: 13.50 months). A significant difference in LRFS between CRC patients (84.1% vs. 50.6%) and other histologies (92.4% vs. 92.4%) was noted, suggesting a higher treatment dose is necessary for CRC patients. The average target dose for metastatic colorectal cancer was 40 - 60 Gy (compared to 100 - 250 Gy for HCC). To better assess sensitivity to therapy and pre-dict side effects, it has been suggested that humoral mediators be evaluated. It was also shown that baseline levels of TNF-α, MCP-1 and VEGF, as well as NGF and CX3CL corre-lated with both tumor volume and radiation-induced liver damage, one of the most serious complications of iBT, indicating their potential role as biomarkers of therapy outcome. Con-clusions: The use of brachytherapy methods in the treatment of liver metastases of various cancers appears to be an interesting and relatively safe therapeutic method alternative to sur-gery. An important challenge remains the selection of an appropriate brachytherapy method and radiation dose for the corresponding initial tumor type from which the metastasis origi-nated.Keywords: liver metastases, brachytherapy, CT-HDRBT, iBT
Procedia PDF Downloads 1031001 Fabrication of SnO₂ Nanotube Arrays for Enhanced Gas Sensing Properties
Authors: Hsyi-En Cheng, Ying-Yi Liou
Abstract:
Metal-oxide semiconductor (MOS) gas sensors are widely used in the gas-detection market due to their high sensitivity, fast response, and simple device structures. However, the high working temperature of MOS gas sensors makes them difficult to integrate with the appliance or consumer goods. One-dimensional (1-D) nanostructures are considered to have the potential to lower their working temperature due to their large surface-to-volume ratio, confined electrical conduction channels, and small feature sizes. Unfortunately, the difficulty of fabricating 1-D nanostructure electrodes has hindered the development of low-temperature MOS gas sensors. In this work, we proposed a method to fabricate nanotube-arrays, and the SnO₂ nanotube-array sensors with different wall thickness were successfully prepared and examined. The fabrication of SnO₂ nanotube arrays incorporates the techniques of barrier-free anodic aluminum oxide (AAO) template and atomic layer deposition (ALD) of SnO₂. First, 1.0 µm Al film was deposited on ITO glass substrate by electron beam evaporation and then anodically oxidized by five wt% phosphoric acid solution at 5°C under a constant voltage of 100 V to form porous aluminum oxide. As the Al film was fully oxidized, a 15 min over anodization and a 30 min post chemical dissolution were used to remove the barrier oxide at the bottom end of pores to generate a barrier-free AAO template. The ALD using reactants of TiCl4 and H₂O was followed to grow a thin layer of SnO₂ on the template to form SnO₂ nanotube arrays. After removing the surface layer of SnO₂ by H₂ plasma and dissolving the template by 5 wt% phosphoric acid solution at 50°C, upright standing SnO₂ nanotube arrays on ITO glass were produced. Finally, Ag top electrode with line width of 5 μm was printed on the nanotube arrays to form SnO₂ nanotube-array sensor. Two SnO₂ nanotube-arrays with wall thickness of 30 and 60 nm were produced in this experiment for the evaluation of gas sensing ability. The flat SnO₂ films with thickness of 30 and 60 nm were also examined for comparison. The results show that the properties of ALD SnO₂ films were related to the deposition temperature. The films grown at 350°C had a low electrical resistivity of 3.6×10-3 Ω-cm and were, therefore, used for the nanotube-array sensors. The carrier concentration and mobility of the SnO₂ films were characterized by Ecopia HMS-3000 Hall-effect measurement system and were 1.1×1020 cm-3 and 16 cm3/V-s, respectively. The electrical resistance of SnO₂ film and nanotube-array sensors in air and in a 5% H₂-95% N₂ mixture gas was monitored by Pico text M3510A 6 1/2 Digits Multimeter. It was found that, at 200 °C, the 30-nm-wall SnO₂ nanotube-array sensor performs the highest responsivity to 5% H₂, followed by the 30-nm SnO₂ film sensor, the 60-nm SnO₂ film sensor, and the 60-nm-wall SnO₂ nanotube-array sensor. However, at temperatures below 100°C, all the samples were insensitive to the 5% H₂ gas. Further investigation on the sensors with thinner SnO₂ is necessary for improving the sensing ability at temperatures below 100 °C.Keywords: atomic layer deposition, nanotube arrays, gas sensor, tin dioxide
Procedia PDF Downloads 2381000 Prominent Lipid Parameters Correlated with Trunk-to-Leg and Appendicular Fat Ratios in Severe Pediatric Obesity
Authors: Mustafa M. Donma, Orkide Donma
Abstract:
The examination of both serum lipid fractions and body’s lipid composition are quite informative during the evaluation of obesity stages. Within this context, alterations in lipid parameters are commonly observed. The variations in the fat distribution of the body are also noteworthy. Total cholesterol (TC), triglycerides (TRG), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C) are considered as the basic lipid fractions. Fat deposited in trunk and extremities may give considerable amount of information and different messages during discrete health states. Ratios are also derived from distinct fat distribution in these areas. Trunk-to-leg fat ratio (TLFR) and trunk-to-appendicular fat ratio (TAFR) are the most recently introduced ratios. In this study, lipid fractions and TLFR, as well as TAFR, were evaluated, and the distinctions among healthy, obese (OB), and morbid obese (MO) groups were investigated. Three groups [normal body mass index (N-BMI), OB, MO] were constituted from a population aged 6 to 18 years. Ages and sexes of the groups were matched. The study protocol was approved by the Non-interventional Ethics Committee of Tekirdag Namik Kemal University. Written informed consent forms were obtained from the parents of the participants. Anthropometric measurements (height, weight, waist circumference, hip circumference, head circumference, neck circumference) were obtained and recorded during the physical examination. Body mass index values were calculated. Total, trunk, leg, and arm fat mass values were obtained by TANITA Bioelectrical Impedance Analysis. These values were used to calculate TLFR and TAFR. Systolic (SBP) and diastolic blood pressures (DBP) were measured. Routine biochemical tests including TC, TRG, LDL-C, HDL-C, and insulin were performed. Data were evaluated using SPSS software. p value smaller than 0.05 was accepted as statistically significant. There was no difference among the age values and gender ratios of the groups. Any statistically significant difference was not observed in terms of DBP, TLFR as well as serum lipid fractions. Higher SBP values were measured both in OB and MO children than those with N-BMI. TAFR showed a significant difference between N-BMI and OB groups. Statistically significant increases were detected between insulin values of N-BMI group and OB as well as MO groups. There were bivariate correlations between LDL and TLFR (r=0.396; p=0.037) as well as TAFR values (r=0.413; p=0.029) in MO group. When adjusted for SBP and DBP, partial correlations were calculated as (r=0.421; p=0.032) and (r=0.438; p=0.025) for LDL-TLFR as well as LDL-TAFR, respectively. Much stronger partial correlations were obtained for the same couples (r=0.475; p=0.019 and r=0.473; p=0.020, respectively) upon controlling for TRG and HDL-C. Much stronger partial correlations observed in MO children emphasize the potential transition from morbid obesity to metabolic syndrome. These findings have concluded that LDL-C may be suggested as a discriminating parameter between OB and MO children.Keywords: children, lipid parameters, obesity, trunk-to-leg fat ratio, trunk-to-appendicular fat ratio
Procedia PDF Downloads 105999 Sensitivity and Uncertainty Analysis of Hydrocarbon-In-Place in Sandstone Reservoir Modeling: A Case Study
Authors: Nejoud Alostad, Anup Bora, Prashant Dhote
Abstract:
Kuwait Oil Company (KOC) has been producing from its major reservoirs that are well defined and highly productive and of superior reservoir quality. These reservoirs are maturing and priority is shifting towards difficult reservoir to meet future production requirements. This paper discusses the results of the detailed integrated study for one of the satellite complex field discovered in the early 1960s. Following acquisition of new 3D seismic data in 1998 and re-processing work in the year 2006, an integrated G&G study was undertaken to review Lower Cretaceous prospectivity of this reservoir. Nine wells have been drilled in the area, till date with only three wells showing hydrocarbons in two formations. The average oil density is around 300API (American Petroleum Institute), and average porosity and water saturation of the reservoir is about 23% and 26%, respectively. The area is dissected by a number of NW-SE trending faults. Structurally, the area consists of horsts and grabens bounded by these faults and hence compartmentalized. The Wara/Burgan formation consists of discrete, dirty sands with clean channel sand complexes. There is a dramatic change in Upper Wara distributary channel facies, and reservoir quality of Wara and Burgan section varies with change of facies over the area. So predicting reservoir facies and its quality out of sparse well data is a major challenge for delineating the prospective area. To characterize the reservoir of Wara/Burgan formation, an integrated workflow involving seismic, well, petro-physical, reservoir and production engineering data has been used. Porosity and water saturation models are prepared and analyzed to predict reservoir quality of Wara and Burgan 3rd sand upper reservoirs. Subsequently, boundary conditions are defined for reservoir and non-reservoir facies by integrating facies, porosity and water saturation. Based on the detailed analyses of volumetric parameters, potential volumes of stock-tank oil initially in place (STOIIP) and gas initially in place (GIIP) were documented after running several probablistic sensitivity analysis using Montecalro simulation method. Sensitivity analysis on probabilistic models of reservoir horizons, petro-physical properties, and oil-water contacts and their effect on reserve clearly shows some alteration in the reservoir geometry. All these parameters have significant effect on the oil in place. This study has helped to identify uncertainty and risks of this prospect particularly and company is planning to develop this area with drilling of new wells.Keywords: original oil-in-place, sensitivity, uncertainty, sandstone, reservoir modeling, Monte-Carlo simulation
Procedia PDF Downloads 188998 Troubling Depictions of Gambian Womanhood in Dayo Forster’s Reading the Ceiling
Authors: A. Wolfe
Abstract:
Dayo Forster’s impressively crafted Reading the Ceiling (2007) enjoys a relatively high profile among Western readers. It is one of only a handful of Gambian novels to be published by an international publisher, Simon and Schuster of London, and was subsequently shortlisted for the Commonwealth Writer’s Best First Book Prize in 2008. It is currently available to US readers in print and as an e-book and has 167 ratings on Goodreads. This paper addresses the possible influence of the book on Western readers’ perception of The Gambia, or Africa in general, through its depiction of the conditions of Gambian women’s lives. Through a close reading of passages and analysis of imagery, intertextuality, and characterization in the book, the paper demonstrates that Forster portrays the culture of The Gambia as oppressively patriarchal and the prospects for young girls who stay in the country as extremely limited. Reading the Ceiling starts on Ayodele’s 18th birthday, the day she has planned to have sex for the first time. Most of the rest of the book is divided into three parts, each following the chain of events that occur after sex with a potential partner. Although Ayodele goes abroad for her education in each of the three scenarios, she ultimately capitulates to the patriarchal politics and demands of marriage and childrearing in The Gambia, settling for relationships with men she does not love, cooking and cleaning for husbands and children, and silencing her own opinions and desires in exchange for the familiar traditions of patriarchal—and, in one case, polygamous—marriage. Each scenario ends with resignation to death, as, after her mother’s funeral, Ayodele admits to herself that she will be next. Forster uses dust and mud imagery throughout the novel to indicate the dinginess of Ayodele’s life as a young woman, and then wife and mother, in The Gambia as well as the inescapability of this life. This depiction of earthen material is also present in the novel’s recounting of an oral tale about a mermaid captured by fishermen, a story that mirrors Ayodele’s ensnarement by traditional marriage customs and gender norms. A review of the fate of other characters in the novel reveals that Ayodele is not the only woman who becomes trapped by the expectations for women in The Gambia, as those who stay in the country end up subservient to their husbands and/or victims of men’s habitual infidelity. It is important to note that Reading the Ceiling is focused on the experiences of a minority—The Gambia’s middle class, Christian urban dwellers with money for education. Regardless of its limited scope, the novel clearly depicts The Gambia as a place where women are simply unable to successfully contend against traditional patriarchal norms. Although this novel evokes vivid imagery of The Gambia through original and compelling descriptions of food preparation, clothing, and scenery, it perhaps does little to challenge stereotypical perceptions of the lives of African women among a Western readership.Keywords: African literature, commonwealth literature, marriage, stereotypes, women
Procedia PDF Downloads 163997 Airport Pavement Crack Measurement Systems and Crack Density for Pavement Evaluation
Authors: Ali Ashtiani, Hamid Shirazi
Abstract:
This paper reviews the status of existing practice and research related to measuring pavement cracking and using crack density as a pavement surface evaluation protocol. Crack density for pavement evaluation is currently not widely used within the airport community and its use by the highway community is limited. However, surface cracking is a distress that is closely monitored by airport staff and significantly influences the development of maintenance, rehabilitation and reconstruction plans for airport pavements. Therefore crack density has the potential to become an important indicator of pavement condition if the type, severity and extent of surface cracking can be accurately measured. A pavement distress survey is an essential component of any pavement assessment. Manual crack surveying has been widely used for decades to measure pavement performance. However, the accuracy and precision of manual surveys can vary depending upon the surveyor and performing surveys may disrupt normal operations. Given the variability of manual surveys, this method has shown inconsistencies in distress classification and measurement. This can potentially impact the planning for pavement maintenance, rehabilitation and reconstruction and the associated funding strategies. A substantial effort has been devoted for the past 20 years to reduce the human intervention and the error associated with it by moving toward automated distress collection methods. The automated methods refer to the systems that identify, classify and quantify pavement distresses through processes that require no or very minimal human intervention. This principally involves the use of a digital recognition software to analyze and characterize pavement distresses. The lack of established protocols for measurement and classification of pavement cracks captured using digital images is a challenge to developing a reliable automated system for distress assessment. Variations in types and severity of distresses, different pavement surface textures and colors and presence of pavement joints and edges all complicate automated image processing and crack measurement and classification. This paper summarizes the commercially available systems and technologies for automated pavement distress evaluation. A comprehensive automated pavement distress survey involves collection, interpretation, and processing of the surface images to identify the type, quantity and severity of the surface distresses. The outputs can be used to quantitatively calculate the crack density. The systems for automated distress survey using digital images reviewed in this paper can assist the airport industry in the development of a pavement evaluation protocol based on crack density. Analysis of automated distress survey data can lead to a crack density index. This index can be used as a means of assessing pavement condition and to predict pavement performance. This can be used by airport owners to determine the type of pavement maintenance and rehabilitation in a more consistent way.Keywords: airport pavement management, crack density, pavement evaluation, pavement management
Procedia PDF Downloads 181996 Assessment of Five Photoplethysmographic Methods for Estimating Heart Rate Variability
Authors: Akshay B. Pawar, Rohit Y. Parasnis
Abstract:
Heart Rate Variability (HRV) is a widely used indicator of the regulation between the autonomic nervous system (ANS) and the cardiovascular system. Besides being non-invasive, it also has the potential to predict mortality in cases involving critical injuries. The gold standard method for determining HRV is based on the analysis of RR interval time series extracted from ECG signals. However, because it is much more convenient to obtain photoplethysmogramic (PPG) signals as compared to ECG signals (which require the attachment of several electrodes to the body), many researchers have used pulse cycle intervals instead of RR intervals to estimate HRV. They have also compared this method with the gold standard technique. Though most of their observations indicate a strong correlation between the two methods, recent studies show that in healthy subjects, except for a few parameters, the pulse-based method cannot be a surrogate for the standard RR interval- based method. Moreover, the former tends to overestimate short-term variability in heart rate. This calls for improvements in or alternatives to the pulse-cycle interval method. In this study, besides the systolic peak-peak interval method (PP method) that has been studied several times, four recent PPG-based techniques, namely the first derivative peak-peak interval method (P1D method), the second derivative peak-peak interval method (P2D method), the valley-valley interval method (VV method) and the tangent-intersection interval method (TI method) were compared with the gold standard technique. ECG and PPG signals were obtained from 10 young and healthy adults (consisting of both males and females) seated in the armchair position. In order to de-noise these signals and eliminate baseline drift, they were passed through certain digital filters. After filtering, the following HRV parameters were computed from PPG using each of the five methods and also from ECG using the gold standard method: time domain parameters (SDNN, pNN50 and RMSSD), frequency domain parameters (Very low-frequency power (VLF), Low-frequency power (LF), High-frequency power (HF) and Total power or “TP”). Besides, Poincaré plots were also plotted and their SD1/SD2 ratios determined. The resulting sets of parameters were compared with those yielded by the standard method using measures of statistical correlation (correlation coefficient) as well as statistical agreement (Bland-Altman plots). From the viewpoint of correlation, our results show that the best PPG-based methods for the determination of most parameters and Poincaré plots are the P2D method (shows more than 93% correlation with the standard method) and the PP method (mean correlation: 88%) whereas the TI, VV and P1D methods perform poorly (<70% correlation in most cases). However, our evaluation of statistical agreement using Bland-Altman plots shows that none of the five techniques agrees satisfactorily well with the gold standard method as far as time-domain parameters are concerned. In conclusion, excellent statistical correlation implies that certain PPG-based methods provide a good amount of information on the pattern of heart rate variation, whereas poor statistical agreement implies that PPG cannot completely replace ECG in the determination of HRV.Keywords: photoplethysmography, heart rate variability, correlation coefficient, Bland-Altman plot
Procedia PDF Downloads 318995 An Integrated Framework for Wind-Wave Study in Lakes
Authors: Moien Mojabi, Aurelien Hospital, Daniel Potts, Chris Young, Albert Leung
Abstract:
The wave analysis is an integral part of the hydrotechnical assessment carried out during the permitting and design phases for coastal structures, such as marinas. This analysis aims in quantifying: i) the Suitability of the coastal structure design against Small Craft Harbour wave tranquility safety criterion; ii) Potential environmental impacts of the structure (e.g., effect on wave, flow, and sediment transport); iii) Mooring and dock design and iv) Requirements set by regulatory agency’s (e.g., WSA section 11 application). While a complex three-dimensional hydrodynamic modelling approach can be applied on large-scale projects, the need for an efficient and reliable wave analysis method suitable for smaller scale marina projects was identified. As a result, Tetra Tech has developed and applied an integrated analysis framework (hereafter TT approach), which takes the advantage of the state-of-the-art numerical models while preserving the level of simplicity that fits smaller scale projects. The present paper aims to describe the TT approach and highlight the key advantages of using this integrated framework in lake marina projects. The core of this methodology is made by integrating wind, water level, bathymetry, and structure geometry data. To respond to the needs of specific projects, several add-on modules have been added to the core of the TT approach. The main advantages of this method over the simplified analytical approaches are i) Accounting for the proper physics of the lake through the modelling of the entire lake (capturing real lake geometry) instead of a simplified fetch approach; ii) Providing a more realistic representation of the waves by modelling random waves instead of monochromatic waves; iii) Modelling wave-structure interaction (e.g. wave transmission/reflection application for floating structures and piles amongst others); iv) Accounting for wave interaction with the lakebed (e.g. bottom friction, refraction, and breaking); v) Providing the inputs for flow and sediment transport assessment at the project site; vi) Taking in consideration historical and geographical variations of the wind field; and vii) Independence of the scale of the reservoir under study. Overall, in comparison with simplified analytical approaches, this integrated framework provides a more realistic and reliable estimation of wave parameters (and its spatial distribution) in lake marinas, leading to a realistic hydrotechnical assessment accessible to any project size, from the development of a new marina to marina expansion and pile replacement. Tetra Tech has successfully utilized this approach since many years in the Okanagan area.Keywords: wave modelling, wind-wave, extreme value analysis, marina
Procedia PDF Downloads 71994 Evaluation of the Cytotoxicity and Cellular Uptake of a Cyclodextrin-Based Drug Delivery System for Cancer Therapy
Authors: Caroline Mendes, Mary McNamara, Orla Howe
Abstract:
Drug delivery systems are proposed for use in cancer treatment to specifically target cancer cells and deliver a therapeutic dose without affecting normal cells. For that purpose, the use of folate receptors (FR) can be considered a key strategy, since they are commonly over-expressed in cancer cells. In this study, cyclodextrins (CD) have being used as vehicles to target FR and deliver the chemotherapeutic drug, methotrexate (MTX). CDs have the ability to form inclusion complexes, in which molecules of suitable dimensions are included within their cavities. Here, β-CD has been modified using folic acid so as to specifically target the FR. Thus, this drug delivery system consists of β-CD, folic acid and MTX (CDEnFA:MTX). Cellular uptake of folic acid is mediated with high affinity by folate receptors while the cellular uptake of antifolates, such as MTX, is mediated with high affinity by the reduced folate carriers (RFCs). This study addresses the gene (mRNA) and protein expression levels of FRs and RFCs in the cancer cell lines CaCo-2, SKOV-3, HeLa, MCF-7, A549 and the normal cell line BEAS-2B, quantified by real-time polymerase chain reaction (real-time PCR) and flow cytometry, respectively. From that, four cell lines with different levels of FRs, were chosen for cytotoxicity assays of MTX and CDEnFA:MTX using the MTT assay. Real-time PCR and flow cytometry data demonstrated that all cell lines ubiquitously express moderate levels of RFC. These experiments have also shown that levels of FR protein in CaCo-2 cells are high, while levels in SKOV-3, HeLa and MCF-7 cells are moderate. A549 and BEAS-2B cells express low levels of FR protein. FRs are highly expressed in all the cancer cell lines analysed when compared to the normal cell line BEAS-2B. The cell lines CaCo-2, MCF-7, A549 and BEAS-2B were used in the cell viability assays. 48 hours treatment with the free drug and the complex resulted in IC50 values of 93.9 µM ± 15.2 and 56.0 µM ± 4.0 for CaCo-2 for free MTX and CDEnFA:MTX respectively, 118.2 µM ± 16.8 and 97.8 µM ± 12.3 for MCF-7, 36.4 µM ± 6.9 and 75.0 µM ± 10.5 for A549 and 132.6 µM ± 16.1 and 288.1 µM ± 26.3 for BEAS-2B. These results demonstrate that free MTX is more toxic towards cell lines expressing low levels of FR, such as the BEAS-2B. More importantly, these results demonstrate that the inclusion complex CDEnFA:MTX showed greater cytotoxicity than the free drug towards the high FR expressing CaCo-2 cells, indicating that it has potential to target this receptor, enhancing the specificity and the efficiency of the drug. The use of cell imaging by confocal microscopy has allowed visualisation of FR targeting in cancer cells, as well as the identification of the interlisation pathway of the drug. Hence, the cellular uptake and internalisation process of this drug delivery system is being addressed.Keywords: cancer treatment, cyclodextrins, drug delivery, folate receptors, reduced folate carriers
Procedia PDF Downloads 307