Search results for: volumetric mass density

Authors: Yubo Bi, Xiao Chen, Shouxiang Lu

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A kind of gas-fueled burner, named Burning Rate Emulator, was proposed for the purpose of the emulation of condensed fuel recently. The gaseous fuel can be pure combustible fuel gas or blends of gaseous fuel or inert gas. However, this concept was recently proposed without detailed study on the combustion characteristic of fuel blends. In this study, two kinds of common gaseous fuels were selected, propane and acetylene, to provide the combustion heat as well as a large amount of smoke, which widely exists in liquid and solid fuel burning process. A set of experiments were carried out using a gas-fueled burner with a diameter of 8 cm. The total volume flow rate of propane and acetylene was kept at 3 liters per minute. The volume fraction of propane varied from 0% to 100% at interval of 10%. It is found that the flame height increases with propane volume fraction, which may be caused by the increase of heat release rate, as the energy density of propane is larger than that of acetylene. The dimensionless flame height is correlated against dimensionless heat release rate, which shows a power function relationship. The radiation fraction of the flame does not show a monotonic relationship with propane volume fraction. With the increase of propane volume fraction from 0% to 100%, the value of radiation fraction increases first and reach a maximum value around 0.46 at a propane volume fraction of 10%, and then decreases continuously to a value of 0.25 at the propane volume fraction of 100%. The flame radiation is related to the soot in the flame. The trend of the radiation fraction reflects that there may be a synergistic effect of soot formation between propane and acetylene which can be guessed from the significantly high radiation fraction at a propane volume fraction of 10%. This work provides data for combustion of gaseous fuel blends pool fire and also give reference on the design of Burning Rate Emulator.

Keywords: Burning Rate Emulator, fuel blends pool fire, flame height, radiation fraction

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Authors: Kiatnarong Supapanmanee, Ekkarin Phongphinittana, Pongsak Nimdum

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Natural fibers are readily available raw materials that are widely used as composite materials. The most common problem facing many researchers with composites made from this fiber is the adhesion between the natural fiber contact surface and the matrix material. Part of the problem is due to the hydrophilic properties of natural fibers and the hydrophobic properties of the matrix material. Based on the aforementioned problems, this research selected bamboo fiber, which is a strong natural fiber in the research study. The first step was to study the effect of the mechanical properties of the pure bamboo strip by testing the tensile strength of different measurement lengths. The bamboo strip was modified surface with sodium hydroxide (NaOH) at 6wt% concentrations for different soaking periods. After surface modification, the physical and mechanical properties of the pure bamboo strip fibers were studied. The modified and unmodified bamboo strips were molded into a composite material using epoxy as a matrix to compare the mechanical properties and adhesion between the fiber surface and the material with tensile and bending tests. In addition, the results of these tests were compared with the finite element method (FEM). The results showed that the length of the bamboo strip affects the strength of the fibers, with shorter fibers causing higher tensile stress. Effects of surface modification of bamboo strip with NaOH, this chemical eliminates lignin and hemicellulose, resulting in the smaller dimension of the bamboo strip and increased density. From the pretreatment results above, it was found that the treated bamboo strip and composite material had better Ultimate tensile stress and Young's modulus. Moreover, that results in better adhesion between bamboo fiber and matrix material.

Keywords: bamboo fiber, bamboo strip, composite material, bamboo composite, pure bamboo, surface modification, mechanical properties of bamboo, bamboo finite element method

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Authors: Tris Kee

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This research investigates social sustainability factors in transitional housing projects and their impact on fostering healthy living environments that promote physical activity and social interaction for residents. Social sustainability is integral to individual health and well-being, as emphasized by Goal 11 of the 2030 Agenda for Sustainable Development, which highlights the importance of safe, affordable, and accessible transport systems, green spaces, and public spaces catering to vulnerable populations' needs. Communal spaces in urban environments are essential for fostering social sustainability, as they serve as settings for physical activities and social interactions among diverse socio-economic groups. Factors such as neighborhood social atmosphere, historical context, social disparity, and mobility can influence the relationship between existing and transitional communities. Mental health effects can be measured through housing segregation, mobility and accessibility, and housing tenure. A significant research gap exists in understanding the living environment of transitional housing in Hong Kong and the social sustainability factors affecting residents' mental and physical health. To address this gap, our study employs a mixed-methods approach combining survey questionnaires and interviews to gather both quantitative and qualitative data. This methodology will provide comprehensive insights into residents' experiences and perceptions. Our research's main contribution is identifying key social sustainability factors in transitional housing and their impact on residents' well-being, informing policy-making and the creation of inclusive, healthy living environments. By addressing this research gap, we aim to provide valuable insights for future housing projects, ultimately promoting the development of socially sustainable transitional communities.

Keywords: social sustainablity, affordable housing, transitional housing, high density housing

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Authors: Taher M. Abou-deif, Esmail M. El-Bialy, Essam E. Khalil

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The paper is devoted to numerically investigating the influence of the air supply outlets geometry on human comfort inside living looms. A computational fluid dynamics model is developed to examine the air flow characteristics of a room with different supply air diffusers. The work focuses on air flow patterns, thermal behavior in the room with few number of occupants. As an input to the full-scale 3-D room model, a 2-D air supply diffuser model that supplies direction and magnitude of air flow into the room is developed. Air distribution effect on thermal comfort parameters was investigated depending on changing the air supply diffusers type, angles and velocity. Air supply diffusers locations and numbers were also investigated. The pre-processor Gambit is used to create the geometric model with parametric features. Commercially available simulation software “Fluent 6.3” is incorporated to solve the differential equations governing the conservation of mass, three momentum and energy in the processing of air flow distribution. Turbulence effects of the flow are represented by the well-developed two equation turbulence model. In this work, the so-called standard k-ε turbulence model, one of the most widespread turbulence models for industrial applications, was utilized. Basic parameters included in this work are air dry bulb temperature, air velocity, relative humidity and turbulence parameters are used for numerical predictions of indoor air distribution and thermal comfort. The thermal comfort predictions through this work were based on ADPI (Air Diffusion Performance Index),the PMV (Predicted Mean Vote) model and the PPD (Percentage People Dissatisfied) model, the PMV and PPD were estimated using Fanger’s model.

Keywords: thermal comfort, Fanger's model, ADPI, energy effeciency

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Authors: Edit Xhajanka, Gresa Baboci, Irene Malagnino, Mimoza Canga, Vito Antonio Malagnino

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Purpose: This study aimed at identifying dental caries increment or reduction, based on factors such as smoking, the scaling of teeth, BMI before and during pregnancy, carbohydrates consumption in relation to childbirth. Material and method: In this observational study, the sample included a total of 98 pregnant women and their age class was 18-45 years old, with a median age of 31.5 years. The setting of the participants resides in Vlora –Albania. Moreover, 64.4% were from the city and 35.6% were from the nearby villages. The study was conducted in the time period January 2018 –June 2021. Body mass index (BMI) was calculated using the standard formula (kg/m²). Maternal pre, during and post-pregnancy BMI was collected by using a validated questionnaire. Statistical analysis was performed using IBM SPSS Statistics 23.0. The significance level (α) was set at 0.05, whereas P-value and analysis of variance (ANOVA) were used to analyze the data. Results: Based on the data analysis, 44.4% of the sample declared that they did smoke before pregnancy and 55.6% not smoked during their pregnancy. As a result, no association was found between smoking and length of pregnancy P=0.95. There is also a strong relation (P=0.000) between the number of teeth with caries before pregnancy and the number of teeth with caries during pregnancy. There is a significant relationship between the scaling of teeth and childbirth, P=0.05. BMI before and during pregnancy in relation to carbohydrates consumption have a significant correlation P=0.004 and P=0.002. The values of BMI before and during pregnancy in relation to childbirth have a strong correlation: P=0.043 and P=0.040, respectively. As a result, obesity was associated with preterm birth. The percentage of children born during 34-36 weeks of pregnancy was 69%, and children born during 32-34 weeks of pregnancy were 31%. CONCLUSION: There was a positive association between dental caries experience, BMI and carbohydrates consumption. Obesity in pregnancy is increasing worldwide; that is why this study suggests the importance of an appropriate weight before and during pregnancy.

Keywords: BMI, dental caries, pregnancy, scaling, smoking

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Authors: Pramod Jagtap, Kisan Jadhav, Neha Dand

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Risperidone (RISP) is an antipsychotic agent and has low water solubility and nontargeted delivery results in numerous side effects. Hence, an attempt was made to develop SLNs hydrogel for intranasal delivery of RISP to achieve maximum bioavailability and reduction of side effects. RISP loaded SLNs composed of 1.65% (w/v) lipid mass were produced by high shear homogenization (HSH) coupled ultrasound (US) method using glyceryl monostearate (GMS) or Imwitor 900K (solid lipid). The particles were loaded with 0.2% (w/v) of the RISP & surface-tailored with a 2.02% (w/v) non-ionic surfactant Tween® 80. Optimization was done using 32 factorial design using Design Expert® software. The prepared SLNs dispersion incorporated into Polycarbophil AA1 hydrogel (0.5% w/v). The final gel formulation was evaluated for entrapment efficiency, particle size, rheological properties, X ray diffraction, in vitro diffusion, ex vivo permeation using sheep nasal mucosa and histopathological studies for nasocilliary toxicity. The entrapment efficiency of optimized SLNs was found to be 76 ± 2 %, polydispersity index <0.3., particle size 278 ± 5 nm. This optimized batch was incorporated into hydrogel. The pH was found to be 6.4 ± 0.14. The rheological behaviour of hydrogel formulation revealed no thixotropic behaviour. In histopathology study, there was no nasocilliary toxicity observed in nasal mucosa after ex vivo permeation. X-ray diffraction data shows drug was in amorphous form. Ex vivo permeation study shows controlled release profile of drug.

Keywords: ex vivo, particle size, risperidone, solid lipid nanoparticles

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Authors: Dafna Knani, Sarit S. Sivan

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Aggrecan, one of the main components of the intervertebral disc (IVD), belongs to the family of proteoglycans (PGs) that are composed of glycosaminoglycan (GAG) chains covalently attached to a core protein. Its primary function is to maintain tissue hydration and hence disc height under the high loads imposed by muscle activity and body weight. Significant PG loss is one of the first indications of disc degeneration. A possible solution to recover disc functions is by injecting a synthetic hydrogel into the joint cavity, hence mimicking the role of PGs. One of the hydrogels proposed is GAG-analogues, based on sulfate-containing polymers, which are responsible for hydration in disc tissue. In the present work, we used molecular dynamics (MD) to study the effect of the hydrogel crosslinking (type and degree) on the swelling behavior of the suggested GAG-analogue biomimetics by calculation of cohesive energy density (CED), solubility parameter, enthalpy of mixing (ΔEmix) and the interactions between the molecules at the pure form and as a mixture with water. The simulation results showed that hydrophobicity plays an important role in the swelling of the hydrogel, as indicated by the linear correlation observed between solubility parameter values of the copolymers and crosslinker weight ratio (w/w); this correlation was found useful in predicting the amount of PEGDA needed for the desirable hydration behavior of (CS)₄-peptide. Enthalpy of mixing calculations showed that all the GAG analogs, (CS)₄ and (CS)₄-peptide are water-soluble; radial distribution function analysis revealed that they form interactions with water molecules, which is important for the hydration process. To conclude, our simulation results, beyond supporting the experimental data, can be used as a useful predictive tool in the future development of biomaterials, such as disc replacement.

Keywords: molecular dynamics, proteoglycans, enthalpy of mixing, swelling

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Authors: Almutazballlah Qablan, Jihan M. Muhaidat, Bana Abu Rajab

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Background: Acne vulgaris is the most common skin condition that general practitioners and dermatologists encounter. It represents a chronic inflammatory disease affecting the pilosebaceous unit. Although acne vulgaris is not a life-threatening condition, it has a considerable psychological impact on the affected person. Acne patients have poor body image, low self-esteem, social isolation, and restricted activities. As part of the emotional impact, increased levels of anxiety, anger, depression, and frustration have also been observed in acne patients. (1) In this study, we want to assess the association between two modifiable risk factors; BMI and smoking, regarding acne vulgaris. Methods: A case-control study was conducted at King Abdullah University Hospital in Irbid, north Jordan in 2019/2020. A total number of 163 Acne cases were collected and interviewed by the author; on the other hand, there were 162 control cases. Anthropometric measures for Acne patients and control individuals were taken, and BMI was calculated. Both groups were asked about smoking habits. Data on subjects between 14 and 33 years of age were extracted. The characteristics of people who reported acne were compared with those with no acne using univariate and multivariate analysis. The Statistical Package for Social Sciences (SPSS) was relied on to analyze the collected data. The crosstabs methods (chi-square) and odd ratios were relied on to test the study hypothesis. Results: Cigarette smoking was highly associated with no-acne, with an odds ratio of 0.4 (95% CI: 0.2–0.9), P-value = 0.018. BMI and waterpipe smoking were not significantly associated with acne in the multivariate analysis. Conclusion: Cigarette smoking was found to be protective from Acne. No significant relation between BMI nor waterpipe smoking and the development of Acne Vulgaris.

Keywords: acne, BMI, smoking, case-control

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Authors: Hong Beom Hur

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Politics in America is polarized. The best illustration of this is the 2016 presidential election result map. States with megacities like California, New York, Illinois, Virginia, and others are marked blue to signify the color of the Democratic party. States located in inland and south like Texas, Florida, Tennesse, Kansas and others are marked red to signify the color of the Republican party. Such a stark difference between two colors, red and blue, combined with geolocations of each state with their borderline remarks one central message; America is divided into two colors between urban Democrats and rural Republicans. This paper seeks to defy the visualization by pointing out its limitations and search for alternative ways to visualize the 2016 election result. One such limitation is that geolocations of each state and state borderlines limit the visualization of population density. As a result, the election result map does not convey the fact that Clinton won the popular vote and only accentuates the voting patterns of urban and rural states. The paper seeks whether an alternative narrative can be observed by factoring in the population number into the size of each state and manipulating the state borderline according to the normalization. Yet another alternative narrative may be reached by factoring the size of each state by the number of the electoral college of each state by voting and visualize the number. Other alternatives will be discussed but are not implemented in visualization. Such methods include dividing the land of America into about 120 million cubes each representing a voter or by the number of whole population 300 million cubes. By exploring these alternative methods to visualize the politics of the 2016 election map, the public may be able to question whether it is possible to be free from the narrative of the divide-conquer when interpreting the election map and to look at both parties as a story of the United States of America.

Keywords: 2016 U.S. presidential election, data visualization, population scale, geo-political

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Authors: Abdelkrim Belhaoua, Jean-Pierre Radoux, Mariana Kuras, Vincent Récamier, Martial Piotto, Karim Elbayed, François Proust, Izzie Namer

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This paper proposes an augmented reality system dedicated to neurosurgery in order to assist the surgeon during an operation. This work is part of the ExtempoRMN project (Funded by Bpifrance) which aims at analyzing during a surgical operation the metabolic content of tumoral brain biopsy specimens by HRMAS NMR. Patients affected with a brain tumor (gliomas) frequently need to undergo an operation in order to remove the tumoral mass. During the operation, the neurosurgeon removes biopsy specimens using image-guided surgery. The biopsy specimens removed are then sent for HRMAS NMR analysis in order to obtain a better diagnosis and prognosis. Image-guided refers to the use of MRI images and a computer to precisely locate and target a lesion (abnormal tissue) within the brain. This is performed using preoperative MRI images and the BrainLab neuro-navigation system. With the patient MRI images loaded on the Brainlab Cranial neuro-navigation system in the operating theater, surgeons can better identify their approach before making an incision. The Brainlab neuro-navigation tool tracks in real time the position of the instruments and displays their position on the patient MRI data. The results of the biopsy analysis by 1H HRMAS NMR are then sent back to the operating theater and superimposed on the 3D localization system directly on the MRI images. The method we have developed to communicate between the HRMAS NMR analysis software and Brainlab makes use of a combination of C++, VTK and the Insight Toolkit using OpenIGTLink protocol.

Keywords: neuro-navigation, augmented reality, biopsy, BrainLab, HR-MAS NMR

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Authors: Daniella L. Pereira, Emeliana G. Imperial, Ingrid Webster, Ian Wiid, Hans Strijdom, Nireshni Chellan, Sanet H. Kotzé

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Rooibos (Aspalathus linearis) is a shrub-like bush native to the Western Cape of South Africa and commonly consumed as a herbal tea. Interest on the anti-oxidant capabilities of the tea have risen based on anecdotal evidence. Rooibos contains polyphenols that contribute to the overall antioxidant capacity of the tea. These polyphenols have been reported to attenuate the effects of oxidative stress in biological systems. The bioavailability of these compounds is compromised when exposed to light, pH fluctuations, and oxidation. It is crucial to evaluate whether the polyphenols in a typical rooibos solution remain constant over time when administered to rats in a research environment. This study aimed to determine the effects of various storage scenarios on the phenolic composition of rooibos tea commonly administered to rodents in experimental studies. A standardised aqueous solution of rooibos tea was filtered and divided into three samples namely fresh, refrigerated, and frozen. Samples were stored in air tight, light excluding bottles. Refrigerated samples were stored at 4°C for seven days. Frozen samples were stored for fourteen days at -20°C. Each sample consisted of two subgroups labeled day 1 and day 7. Teas marked day 7 of each group were kept in air tight, light protected bottles at room temperature for an additional week. All samples (n=6) were freeze-dried and underwent polyphenol characterization using liquid chromatography-mass spectrometry. The phenolic composition remained constant throughout all groups. This indicates that rooibos tea can be safely stored at the above conditions without compromising the phenolic viability of the tea typically used for research purposes.

Keywords: Aspalathus linearis, experimental studies, polyphenols, storage

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Authors: Arkadiusz Zurek

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The potential of using drones is visible in many areas of logistics, especially in terms of their use for monitoring and control of many processes. The technologies implemented in the last decade concern new possibilities for companies that until now have not even considered them, such as warehouse inventories. Unmanned aerial vehicles are no longer seen as a revolutionary tool for Industry 4.0, but rather as tools in the daily work of factories and logistics operators. The research problem is to develop a method for measuring the weight of goods in a selected link of the clothing supply chain by drones. However, the purpose of this article is to analyze the causes of errors in traditional measurements, and then to identify adverse events related to the use of drones for the inventory of a heap of textiles intended for production purposes. On this basis, it will be possible to develop guidelines to eliminate the causes of these events in the measurement process using drones. In a real environment, work was carried out to determine the volume and weight of textiles, including, among others, weighing a textile sample to determine the average density of the assortment, establishing a local geodetic network, terrestrial laser scanning and photogrammetric raid using an unmanned aerial vehicle. As a result of the analysis of measurement data obtained in the facility, the volume and weight of the assortment and the accuracy of their determination were determined. In this article, this work presents how such heaps are currently being tested, what adverse events occur, indicate and describes the current use of photogrammetric techniques of this type of measurements so far performed by external drones for the inventory of wind farms or construction of the station and compare them with the measurement system of the aforementioned textile heap inside a large-format facility.

Keywords: drones, unmanned aerial system, UAS, indoor system, security, process automation, cost optimization, photogrammetry, risk elimination, industry 4.0

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Authors: Lapatrada Numkham, Saowaluk Khakhong, Jeeraporn Kummabutr

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Non-communicable diseases (NCDs) are the leading cause of death in worldwide. Thailand also concerns and focuses on reduction a new case of these diseases. Community Health Volunteers (CHV) is important health personnel in primary health care and performs as a health leader in the community. If the health of CHV changes, it would impact on the performance to promote health of families and community. This cross-sectional study aimed to 1) describe the health status of community health volunteers and 2) examine the factors associated with health status among community health volunteers. The sample included 360 community health volunteers in a province in central Thailand during September-December 2014. Data were collected using questionnaires on health information, knowledge of health behaviors, and health behaviors. Body weight, height, waist circumference (WC), blood pressure (BP), and blood glucose (BS) (fingertip) were assessed. Data were analyzed using descriptive statistics and chi-square test. There were three hundred and sixty participants with 82.5% being women. The mean age was 54 + 8.9 years. Forty-seven percent of the participants had co-morbidities. Hypertension was the most common co-morbidity (26.7%). The results revealed that the health status of the volunteers included: no underlying disease, having risk of hypertension (HT) & diabetes mellitus (DM), and having HT&DM at 38.3%, 30.0%, and 31.7% respectively. The chi-square test revealed that the factors associated with health status among the volunteers were gender, age, WC and body mass index (BMI). The results suggested that community health nurses should; 1) implement interventions to decrease waist circumference and lose weight through education programs, especially females; 2) monitor people that have a risk of HT&DM and that have HT&DM by meeting and recording BP level, BS level, WC and BMI; and 3) collaborate with a district public health officer to initiate a campaign to raise awareness of the risks of chronic diseases among community health volunteers.

Keywords: community health volunteers, health status, risk of non-communicable disease, Thailand

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Authors: Mauricio Cruz, Andrés Díaz García, Martha Isabel Gómez, Juan Carlos Serrato Bermúdez

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The disadvantages of using natural substrates in SSF processes have been well recognized and mainly are associated to gradual decomposition of the substrate, formation of agglomerates and decrease of porosity bed generating limitations in the mass and heat transfer. Additionally, in several cases, materials with a high agricultural value such as sour milk, beets, rice, beans and corn have been used. Thus, the use of economic inert supports (natural or synthetic) in combination with a nutrient suspension for the production of biocontrol microorganisms is a good alternative in SSF processes, but requires further studies in the fields of modeling and optimization. Therefore, the aim of this work is to compare the performance of two inert supports, a synthetic (polyurethane foam) and a natural one (rice husk), identifying the factors that have the major effects on the productivity of T. asperellum Th204 and the maximum specific growth rate in a PROPHYTA L05® fixed bed bioreactor. For this, the six factors C:N ratio, temperature, inoculation rate, bed height, air moisture content and airflow were evaluated using a fractional design. The factors C:N and air flow were identified as significant on the productivity (expressed as conidia/dry substrate•h). The polyurethane foam showed higher maximum specific growth rate (0.1631 h-1) and productivities of 3.89 x107 conidia/dry substrate•h compared to rice husk (2.83x106) and natural substrate based on rice (8.87x106) used as control. Finally, a quadratic model was generated and validated, obtaining productivities higher than 3.0x107 conidia/dry substrate•h with air flow at 0.9 m3/h and C:N ratio at 18.1.

Keywords: bioprocess, scale up, fractional design, C:N ratio, air flow

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Authors: Mihai-Ionut Firescu, Mark A. P. Carson

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We present a case of inferior vena cava agenesis (IVCA) associated with bilateral deep venous thrombosis (DVT) in a patient with Beckwith-Wiedemann syndrome (BWS). In adult patients with BWS presenting with bilateral lower limb oedema, specific aetiological factors should be considered. These include cardiomyopathy and intraabdominal tumours. Congenital malformations of the IVC, through causing relative venous stasis, can lead to lower limb oedema either directly or indirectly by favouring lower limb venous thromboembolism; however, they are yet to be reported as an associated feature of BWS. Given its life-threatening potential, the prompt initiation of treatment for bilateral DVT is paramount. In BWS patients, however, this can prove more complicated. Due to overgrowth, the above-average birth weight can continue throughout childhood. In this case, the patient’s weight reached 170 kg, impacting on anticoagulation choice, as direct oral anticoagulants have a limited evidence base in patients with a body mass above 120 kg. Furthermore, the presence of IVCA leads to a long-term increased venous thrombosis risk. Therefore, patients with IVCA and bilateral DVT warrant specialist consideration and may benefit from multidisciplinary team management, with hematology and vascular surgery input. Conclusion: Here, we showcased a rare cause for bilateral lower limb oedema, respectively bilateral deep venous thrombosis complicating IVCA in a patient with Beckwith-Wiedemann syndrome. The importance of this case lies in its novelty, as the association between IVC agenesis and BWS has not yet been described. Furthermore, the treatment of DVT in such situations requires special consideration, taking into account the patient’s weight and the presence of a significant, predisposing vascular abnormality.

Keywords: Beckwith-Wiedemann syndrome, bilateral deep venous thrombosis, inferior vena cava agenesis, venous thromboembolism

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Authors: Januar Parlaungan Siregar, Davindra Brabu Mathivanan, Dandi Bachtiar, Mohd Ruzaimi Mat Rejab, Tezara Cionita

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Natural fibres play a significant role in mass industries such as automotive, construction and sports. Many researchers have found that the natural fibres are the best replacement for the synthetic fibres in terms of cost, safety, and degradability due to the shortage of landfill and ingestion of non biodegradable plastic by animals. This study mainly revolved around pineapple leaf fibre (PALF) which is available abundantly in tropical countries and with excellent mechanical properties. The composite formed in this study is highly biodegradable as both fibre and matrix are both derived from natural based products. The matrix which is polylactic acid (PLA) is made from corn starch which gives the upper hand as both material are renewable resources are easier to degrade by bacteria or enzyme. The PALF is treated with different alkaline solution to remove excessive moisture in the fibre to provide better interfacial bonding with PLA. Thereafter the PALF is washed with distilled water several times before placing in vacuum oven at 80°C for 48 hours. The dried PALF later were mixed with PLA using extrusion method using fibre in percentage of 30 by weight. The temperature for all zone were maintained at 160°C with the screw speed of 50 rpm for better bonding and afterwards the products of the mixture were pelletized using pelletizer. The pellets were placed in the specimen-sized mould for hot compression under the temperature of 170°C at 5 MPa for 5 min and subsequently were cold pressed under room temperature at 5 MPa for 5 min. The specimen were tested for tensile and flexure strength according to American Society for Testing and Materials (ASTM) D638 and D790 respectively. The effect of surface modification on PALF with different alkali solution will be investigated and compared.

Keywords: natural fibre, PALF, PLA, composite

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Authors: Reza Soleimanpour, Ching Tai Ng

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Fibre-composites are widely used in various structures due to their attractive properties such as higher stiffness to mass ratio and better corrosion resistance compared to metallic materials. However, one serious weakness of this composite material is delamination, which is a subsurface separation of laminae. A low level of this barely visible damage can cause a significant reduction in residual compressive strength. In the last decade, the application of guided waves for damage detection has been a topic of significant interest for many researches. Among all guided wave techniques, nonlinear guided wave has shown outstanding sensitivity and capability for detecting different types of damages, e.g. cracks and delaminations. So far, most of researches on applications of nonlinear guided wave have been dedicated to isotropic material, such as aluminium and steel, while only a few works have been done on applications of nonlinear characteristics of guided waves in anisotropic materials. This study investigates the nonlinear interactions of the fundamental antisymmetric lamb wave (A0) with delamination in composite laminates using three-dimensional (3D) explicit finite element (FE) simulations. The nonlinearity considered in this study arises from interactions of two interfaces of sub-laminates at the delamination region, which generates contact acoustic nonlinearity (CAN). The aim of this research is to investigate the phenomena of CAN in composite laminated beams by a series of numerical case studies. In this study interaction of fundamental antisymmetric lamb wave with delamination of different sizes are studied in detail. The results show that the A0 lamb wave interacts with the delaminations generating CAN in the form of higher harmonics, which is a good indicator for determining the existence of delaminations in composite laminates.

Keywords: contact acoustic nonlinearity, delamination, fibre reinforced composite beam, finite element, nonlinear guided waves

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Authors: Filimonova Alexanra

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Inviscid incompressible fluid flows are considered. The object of the study is a vortex parquet – a structure consisting of distributed vortex spots of different directions, occupying the entire plane. The main attention is paid to the study of advection processes of passive particles in the corresponding velocity field. The dynamics of the vortex structures is considered in a rectangular region under the assumption that periodic boundary conditions are imposed on the stream function. Numerical algorithms are based on the solution of the initial-boundary value problem for nonstationary Euler equations in terms of vorticity and stream function. For this, the spectral-vortex meshless method is used. It is based on the approximation of the stream function by the Fourier series cut and the approximation of the vorticity field by the least-squares method from its values in marker particles. A vortex configuration, consisting of four vortex patches is investigated. Results of a numerical study of the dynamics and interaction of the structure are presented. The influence of the patch radius and the relative position of positively and negatively directed patches on the processes of interaction and mixing is studied. The obtained results correspond to the following possible scenarios: the initial configuration does not change over time; the initial configuration forms a new structure, which is maintained for longer times; the initial configuration returns to its initial state after a certain period of time. The processes of mass transfer of vorticity by liquid particles on a plane were calculated and analyzed. The results of a numerical analysis of the particles dynamics and trajectories on the entire plane and the field of local Lyapunov exponents are presented.

Keywords: ideal fluid, meshless methods, vortex structures in liquids, vortex parquet.

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Authors: Alireza Vahid, Santu Rana, Sunil Gupta, Pratibha Vellanki, Svetha Venkatesh, Thomas Dorin

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Aluminum is the preferred material for lightweight applications and its alloys are constantly improving. The high strength 7xxx alloys have been extensively used for structural components in aerospace and automobile industries for the past 50 years. In the next decade, a great number of airplanes will be retired, providing an obvious source of valuable used metals and great demand for cost-effective methods to re-use these alloys. The design of proper aerospace alloys is primarily based on optimizing strength and ductility, both of which can be improved by controlling the additional alloying elements as well as heat treatment conditions. In this project, we explore the design of high-performance alloys with 7xxx as a base material. These designed alloys have to be optimized and improved to compare with modern 7xxx-series alloys and to remain competitive for aircraft manufacturing. Aerospace alloys are extremely complex with multiple alloying elements and numerous processing steps making optimization often intensive and costly. In the present study, we used Bayesian optimization algorithm, a well-known adaptive design strategy, to optimize this multi-variable system. An Al alloy was proposed and the relevant heat treatment schedules were optimized, using the tensile yield strength as the output to maximize. The designed alloy has a maximum yield strength and ultimate tensile strength of more than 730 and 760 MPa, respectively, and is thus comparable to the modern high strength 7xxx-series alloys. The microstructure of this alloy is characterized by electron microscopy, indicating that the increased strength of the alloy is due to the presence of a high number density of refined precipitates.

Keywords: aluminum alloys, Bayesian optimization, heat treatment, tensile properties

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Authors: Seema Ahlawat, Parul Saxena, Malik Zainul Abdin

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Malaria is a major health problem in many developing countries. The parasite responsible for the vast majority of fatal malaria infections is Plasmodium falciparum. Unfortunately, most Plasmodium strains including P. falciparum have become resistant to most of the antimalarials including chloroquine, mefloquine, etc. To combat this problem, WHO has recommended the use of artemisinin and its derivatives in artemisinin based combination therapy (ACT). Due to its current use in artemisinin based-combination therapy (ACT), its global demand is increasing continuously. But, the relatively low yield of artemisinin in A. annua L. plants and unavailability of economically viable synthetic protocols are the major bottlenecks for its commercial production and clinical use. Chemical synthesis of artemisinin is also very complex and uneconomical. The hairy root system, using the Agrobacterium rhizogenes LBA 9402 strain to enhance the production of artemisinin in A. annua L., is developed in our laboratory. The transgenic nature of hairy root lines and the copy number of trans gene (rol B) were confirmed using PCR and Southern Blot analyses, respectively. The effect of different concentrations of Piriformospora indica on artemisinin production in hairy root cultures were evaluated. 3% P. indica has resulted 1.97 times increase in artemisinin production in comparison to control cultures. The effects of P. indica on artemisinin production was positively correlated with regulatory genes of MVA, MEP and artemisinin biosynthetic pathways, viz. hmgr, ads, cyp71av1, aldh1, dxs, dxr and dbr2 in hairy root cultures of A. annua L. Mass scale cultivation of A. annua L. hairy roots by plant tissue culture technology may be an alternative route for production of artemisinin. A comprehensive investigation of the hairy root system of A. annua L. would help in developing a viable process for the production of artemisinin. The efficiency of the scaling up systems still needs optimization before industrial exploitation becomes viable.

Keywords: A. annua L., artemisinin, hairy root cultures, malaria

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Authors: Awad Khireldin, Colin Law

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Runways are the major infrastructure of airports around the world. Efficient operations of runways are key to ensure that airports are running smoothly with minimal delays. There are many factors that affect the efficiency of runway operations, such as the aircraft wake separation, runways system configuration, the fleet mix, and the runways separation distance. This paper aims to address how to maximize runway operations using a Discrete Event Simulation model. A case study of Cairo International Airport (CIA) is developed to maximize the utilizing of three parallel runways using a simulation model. Different scenarios have been designed where every runway could be assigned for arrival, departure, or mixed operations. A benchmarking study was also included to compare the actual to the proposed results to spot the potential improvements. The simulation model shows that there is a significant difference in utilization and delays between the actual and the proposed ones, there are several recommendations that can be provided to airport management, in the short and long term, to increase the efficiency and to reduce the delays. By including the recommendation with different operations scenarios, such as upgrading the airport slot Coordination from Level 1 to Level 2 in the short term. In the long run, discuss the possibilities to increase the International Air Transport association (IATA) slot coordination to Level 3 as more flights are expected to be handled by the airport. Technological advancements such as radar in the approach full airside simulation model could improve the airport performance where the airport is recommended to review the standard operations procedures with the appropriate authorities. Also, the airport can adopt a future operational plan to accommodate the forecasted additional traffic density in case of adding a fourth terminal building to increase the airport capacity.

Keywords: airport performance, runway, discrete event simulation, capacity, airside

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Authors: Eric Beyegue, Boris Azantza, Judith Laure Ngondi, Julius E. Oben

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Background: Dietary supplement may potentially help to fight obesity and other metabolic disorders such as adipogenesis, insulin resistance, and inflammation. The present study aimed to test whether supplementation with African walnuts (Aw) could have an effect on adipogenesis and others dysfunctions associated with obesity in rats. Methods: Wistar rats were fed with standard diet (SD) or high-fat high-sucrose diet (HFS) and HFS with supplemented (HFS-Aw) for eight weeks. Results: HFS diet-induced body weight gain and increased fat mass compared to SD. In addition HFS-fed rats developed fasting hyperglycaemia and insulinaemia as well as insulin resistance. Aw supplementation in HFS rats had a protective effect against adipose tissues weigh gain but slightly against body weight gain and major study related disorders. This could be mainly due to decreased food intake dependently of effect in food intake in central nervous system, which decreased in HFS rats supplemented with African walnut compared to the HFS-diet group. Interestingly, African walnut supplementation induced a slight decrease of fasting glycaemia, insulinaemia and Nitric Oxide which could partially explain its minor protective effect against diet-induced insulin resistance. Additionally a decrease in hepatic TG and transaminases levels suggesting a protective effect against liver injury. Conclusion: Taken together these data suggested that supplementation of African walnut could be used to prevent adipose weight gain and related disorders on the other hand, minimally reduced insulin resistance.

Keywords: African walnut, dietary fiber, insulin resistance, oxidative stress

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Authors: Jin Hwan Cheong, Mina Hwang, Myung Hoon Han, Je Il Ryu, Young ha Oh, Seong Ho Koh, Wu Duck Won, Byung Jin Ha

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Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) has been reported to play critical roles in the proliferation of various cancer cells. However, the roles of LGR5 in brain tumors and the specific intracellular signaling proteins directly associated with it remain unknown. Expression of LGR5 was first measured in normal brain tissue, meningioma, and pituitary adenoma of humans. To identify the downstream signaling pathways of LGR5, siRNA-mediated knockdown of LGR5 was performed in SH-SY5Y neuroblastoma cells followed by proteomics analysis with 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In addition, the expression of LGR5-associated proteins was evaluated in LGR5-inꠓhibited neuroblastoma cells and in human normal brain, meningioma, and pituitary adenoma tissue. Proteomics analysis showed 12 protein spots were significantly different in expression level (more than two-fold change) and subsequently identified by peptide mass fingerprinting. A protein association network was constructed from the 12 identified proteins altered by LGR5 knockdown. Direct and indirect interactions were identified among the 12 proteins. HSP 90-beta was one of the proteins whose expression was altered by LGR5 knockdown. Likewise, we observed decreased expression of proteins in the hnRNP subfamily following LGR5 knockdown. In addition, we have for the first time identified significantly higher hnRNP family expression in meningioma and pituitary adenoma compared to normal brain tissue. Taken together, LGR5 and its downstream sigꠓnaling play critical roles in neuroblastoma and brain tumors such as meningioma and pituitary adenoma.

Keywords: LGR5, neuroblastoma, meningioma, pituitary adenoma, hnRNP

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Authors: David Karasek, Veronika Kubickova, Ondrej Krystynik, Dominika Goldmannova, Lubica Cibickova, Jan Schovanek

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Introduction: Adiponectin, adipocyte-fatty acid-binding protein (A-FABP), and Wnt1 inducible signaling pathway protein-1 (WISP-1) are adipokines particularly associated with insulin resistance. The aim of the study was to compare their levels in women with gestational diabetes (GDM), type 2 diabetes mellitus (T2DM) and healthy controls and determine their relation with metabolic parameters. Methods: Fifty women with GDM, 50 women with T2DM, and 35 healthy women were included in the study. In addition to adipokines, anthropometric, lipid parameters, and markers, insulin resistance, and glucose control were assessed in all participants. Results: Compared to healthy controls only significantly lower levels of adiponectin were detected in women with GDM, whereas lower levels of adiponectin, higher levels of A-FABP and of WISP-1 were present in women with T2DM. Women with T2DM had also lower levels of adiponectin and higher levels of A-FABP compared to women with GDM. In women with GDM or T2DM adiponectin correlated negatively with body mass index (BMI), triglycerides (TG), C-peptide and positively with HDL-cholesterol; A-FABP positively correlated with BMI, TG, waist, and C-peptide. Moreover, there was a positive correlation between WISP-1 and C-peptide in women with T2DM. Conclusion: Adverse adipokines production detecting dysfunctional fat tissue is in women with GDM less presented than in women with T2DM, but more expressed compared to healthy women. Acknowledgment: Supported by AZV NV18-01-00139 and MH CZ DRO (FNOl, 00098892).

Keywords: adiponectin, adipocyte-fatty acid binding protein, wnt1 inducible signaling pathway protein-1, gestational diabetes, type 2 diabetes mellitus

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Authors: Vladimir A. Vinnikov

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The paper proposes a model of an inhomogeneous rock mass with initially random distribution of microcracks on mineral grain boundaries. It describes the behavior of cracks in a medium under the effect of thermal field, the medium heated instantaneously to a predetermined temperature. Crack growth occurs according to the concept of fracture mechanics provided that the stress intensity factor K exceeds the critical value of Kc. The modeling of thermally induced acoustic emission memory effects is based on the assumption that every event of crack nucleation or crack growth caused by heating is accompanied by a single acoustic emission event. Parameters of the thermally induced acoustic emission memory effect produced by cyclic heating and cooling (with the temperature amplitude increasing from cycle to cycle) were calculated for several rock texture types (massive, banded, and disseminated). The study substantiates the adaptation of the proposed model to humidity interference with the thermally induced acoustic emission memory effect. The influence of humidity on the thermally induced acoustic emission memory effect in quasi-homogeneous and banded rocks is estimated. It is shown that such modeling allows the structure and texture of rocks to be taken into account and the influence of interference factors on the distinctness of the thermally induced acoustic emission memory effect to be estimated. The numerical modeling can be used to obtain information about the thermal impacts on rocks in the past and determine the degree of rock disturbance by means of non-destructive testing.

Keywords: degree of rock disturbance, non-destructive testing, thermally induced acoustic emission memory effects, structure and texture of rocks

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Authors: Miranda I. Dosunmu, Orok E. Oyo-Ita, Inyang O. Oyo-Ita

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Polycyclic aromatic hydrocarbons (PAHs) are a class of priority listed organic pollutants due to their carcinogenicity, mutagenity, acute toxicity and persistency in the environment. The distribution and historical changes of PAHs contamination in recent sediment cores from the Imo River were investigated using gas chromatography coupled with mass spectrometer. The concentrations of total PAHs (TPAHs) ranging from 402.37 ng/g dry weight (dw) at the surface layer of the Estuary zone (ESC6; 0-5 cm) to 92,388.59 ng/g dw at the near surface layer of the Afam zone (ASC5; 5-10 cm) indicate that PAHs contamination was localized not only between sample sites but also within the same cores. Sediment-depth profiles for the four (Afam, Mangrove, Estuary and illegal Petroleum refinery) cores revealed irregular distribution patterns in the TPAH concentrations except the fact that these levels became maximized at the near surface layers (5-10 cm) corresponding to a geological time-frame of about 1996-2004. This time scale coincided with the period of intensive bunkering and oil pipeline vandalization by the Niger Delta militant groups. Also a general slight decline was found in the TPAHs levels from near the surface layers (5-10 cm) to the most recent top layers (0-5 cm) of the cores, attributable to the recent effort by the Nigerian government in clamping down the illegal activity of the economic saboteurs. Therefore, the recent amnesty period granted to the militant groups should be extended. Although mechanism of perylene formation still remains enigmatic, examination of its distributions down cores indicates natural biogenic, pyrogenic and petrogenic origins for the compound at different zones. Thus, the characteristic features of the Imo River environment provide a means of tracing diverse origins for perylene.

Keywords: perylene, historical trend, distribution, origin, Imo River

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Authors: Donatella Giuliani

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In this research, we propose an unsupervised grayscale image segmentation method based on a combination of the Firefly Algorithm and the Gaussian Mixture Model. Firstly, the Firefly Algorithm has been applied in a histogram-based research of cluster means. The Firefly Algorithm is a stochastic global optimization technique, centered on the flashing characteristics of fireflies. In this context it has been performed to determine the number of clusters and the related cluster means in a histogram-based segmentation approach. Successively these means are used in the initialization step for the parameter estimation of a Gaussian Mixture Model. The parametric probability density function of a Gaussian Mixture Model is represented as a weighted sum of Gaussian component densities, whose parameters are evaluated applying the iterative Expectation-Maximization technique. The coefficients of the linear super-position of Gaussians can be thought as prior probabilities of each component. Applying the Bayes rule, the posterior probabilities of the grayscale intensities have been evaluated, therefore their maxima are used to assign each pixel to the clusters, according to their gray-level values. The proposed approach appears fairly solid and reliable when applied even to complex grayscale images. The validation has been performed by using different standard measures, more precisely: the Root Mean Square Error (RMSE), the Structural Content (SC), the Normalized Correlation Coefficient (NK) and the Davies-Bouldin (DB) index. The achieved results have strongly confirmed the robustness of this gray scale segmentation method based on a metaheuristic algorithm. Another noteworthy advantage of this methodology is due to the use of maxima of responsibilities for the pixel assignment that implies a consistent reduction of the computational costs.

Keywords: clustering images, firefly algorithm, Gaussian mixture model, meta heuristic algorithm, image segmentation

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Authors: Mitchell Stanton

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Background: Endovascular management is well established as a mainstay treatment option for cerebral aneurysms. It is also well established that immediate post procedural imaging can be difficult to interpret due to the presence of contrast material. However, through the use of Dual-Energy computed tomography, it has become possible to differentiate contrast extravasation and intracranial haemorrhage. This case illustrates the importance of this technology following endovascular treatment of an unruptured cerebral aneurysm. Case Presentation: A 79-year-old female was found to have an unruptured large intracavernous ICA fusiform aneurysm on CT Brain Angiogram after presenting with acute ophthalmoplegia. This ophthalmoplegia was caused by mass effect from the aneurysm and subsequently the aneurysm was treated with an endovascular flow diverting stent. CT brain was performed post operatively due to a reduced level of consciousness and this showed diffuse subarachnoid hyperdensity of the left hemisphere. The use of Dual-Energy CT allowed accurate differentiation and illustrated diffuse contrast material extravasation, allowing patient to continue on dual-antiplatelets and therapeutic anticoagulation to reduce the risk of ischaemic injury post endovascular stent. Conclusion: Endovascular treatment options for management of intracranial aneurysms are constantly evolving. The use of Dual-Energy CT therefore has an integral role in accurately diagnosing any post-operative complications. Specifically, differentiating between subarachnoid haemorrhage and contrast extravasation is vital in these patients due to the significant consequences to their ongoing management in regards to continuation or cessation of antiplatelets or anticoagulation. With increasing access to this technology, its use should become standard practice in the post-operative investigation of these patients undergoing endovascular treatment.

Keywords: aneurysm, computed tomography, contrast extravasation, dual-energy CT, endovascular, subarachnoid haemorrhage

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Authors: Dante J. Dorantes-González, Aldrin Balsa-Yepes

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Existing learning techniques such as problem-based learning, project-based learning, or case study learning are learning techniques that focus mainly on technical details, but give no specific guidelines on learner’s experience and emotional learning aspects such as arousal salience and valence, being emotional states important factors affecting engagement and retention. Some approaches involving emotion in educational settings, such as social and emotional learning, lack neuroscientific rigorousness and use of specific neurobiological mechanisms. On the other hand, neurobiology approaches lack educational applicability. And educational approaches mainly focus on cognitive aspects and disregard conditioning learning. First, authors start explaining the reasons why it is hard to learn thoughtfully, then they use the method of neurobiological mapping to track the main limbic system functions, such as the reward circuit, and its relations with perception, memories, motivations, sympathetic and parasympathetic reactions, and sensations, as well as the brain cortex. The authors conclude explaining the major finding: The mechanisms of nonconscious learning and the triggers that guarantee long-term memory potentiation. Afterward, the educational framework for practical application and the instructors’ guidelines are established. An implementation example in engineering education is given, namely, the study of tuned-mass dampers for earthquake oscillations attenuation in skyscrapers. This work represents an original learning technique based on nonconscious learning mechanisms to enhance long-term memories that complement existing cognitive learning methods.

Keywords: emotion, emotion-enhanced memory, learning technique, STEM

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Authors: Ansah Iris Baffour, Dong-Ho Kim, Sung-Gyu Park

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The ongoing COVID-19 pandemic, caused by the SARS-CoV-2 virus and is gradually shifting to an endemic phase which implies the outbreak is far from over and will be difficult to eradicate. Global cooperation has led to unified precautions that aim to suppress epidemiological spread (e.g., through travel restrictions) and reach herd immunity (through vaccinations); however, the primary strategy to restrain the spread of the virus in mass populations relies on screening protocols that enable rapid on-site diagnosis of infections. Herein, we employed surface enhanced Raman spectroscopy (SERS) for the rapid detection of SARS-CoV-2 lysate on an Au-modified Au nanodimple(AuND)electrode. Through in situone-pot Au electrodeposition on the AuND electrode, Au-lysate nanocomposites were synthesized, generating3D internal hotspots for large SERS signal enhancements within 30 s of the deposition. The capture of lysate into newly generated plasmonic nanogaps within the nanocomposite structures enhanced metal-spike protein contact in 3D spaces and served as hotspots for sensitive detection. The limit of detection of SARS-CoV-2 lysate was 5 x 10-2 PFU/mL. Interestingly, ultrasensitive detection of the lysates of influenza A/H1N1 and respiratory syncytial virus (RSV) was possible, but the method showed ultimate selectivity for SARS-CoV-2 in lysate solution mixtures. We investigated the practical application of the approach for rapid on-site diagnosis by detecting SARS-CoV-2 lysate spiked in normal human saliva at ultralow concentrations. The results presented demonstrate the reliability and sensitivity of the assay for rapid diagnosis of COVID-19.

Keywords: label-free detection, nanocomposites, SARS-CoV-2, surface-enhanced raman spectroscopy

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