Search results for: active sonar
3140 Increase of the Nanofiber Degradation Rate Using PCL-PEO and PCL-PVP as a Shell in the Electrospun Core-Shell Nanofibers Using the Needleless Blades
Authors: Matej Buzgo, Erico Himawan, Ksenija JašIna, Aiva Simaite
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Electrospinning is a versatile and efficient technology for producing nanofibers for biomedical applications. One of the most common polymers used for the preparation of nanofibers for regenerative medicine and drug delivery applications is polycaprolactone (PCL). PCL is a biocompatible and bioabsorbable material that can be used to stimulate the regeneration of various tissues. It is also a common material used for the development of drug delivery systems by blending the polymer with small active molecules. However, for many drug delivery applications, e.g. cancer immunotherapy, PCL biodegradation rate that may exceed 9 months is too long, and faster nanofiber dissolution is needed. In this paper, we investigate the dissolution and small molecule release rates of PCL blends with two hydrophilic polymers: polyethylene oxide (PEO) or polyvinylpyrrolidone (PVP). We show that adding hydrophilic polymer to the PCL reduces the water contact angle, increases the dissolution rate, and strengthens the interactions between the hydrophilic drug and polymer matrix that further sustain its release. Finally using this method, we were also able to increase the nanofiber degradation rate when PCL-PEO and PCL-PVP were used as a shell in the electrospun core-shell nanofibers and spread up the release of active proteins from their core. Electrospinning can be used for the preparation of the core-shell nanofibers, where active ingredients are encapsulated in the core and their release rate is regulated by the shell. However, such fibers are usually prepared by coaxial electrospinning that is an extremely low-throughput technique. An alternative is emulsion electrospinning that could be upscaled using needleless blades. In this work, we investigate the possibility of using emulsion electrospinning for encapsulation and sustained release of the growth factors for the development of the organotypic skin models. The core-shell nanofibers were prepared using the optimized formulation and the release rate of proteins from the fibers was investigated for 2 weeks – typical cell culture conditions.Keywords: electrospinning, polycaprolactone (PCL), polyethylene oxide (PEO), polyvinylpyrrolidone (PVP)
Procedia PDF Downloads 2743139 History and Survey on Volunteer Fire Departments in Serbia
Authors: Mirjana Đ. Laban, Dragan N. Đurica, Nemanja M. Erceg
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Volunteer fire departments (VFD) in Serbia were established as civic associations in XIX Century. The founders and members of the first VFDs were prominent members of local communities. Today, those are volunteer organizations for preventing and extinguishing fires and rescuing people and property in various accidents. The paper presents the results of research about the number and resources of active VFDs done in Autonomous Province of Vojvodina, Serbia and about activities they perform today. The survey was done based on data provided by all registered VFDs in Vojvodina. Firefighters Association of Vojvodina includes 35 municipal firefighting associations, 230 volunteer fire departments with 5,300 active members in qualified fire units and more than 15,000 supporting members. Volunteer involvement is primarily an expression of high moral values and as such it has to be respected and stimulated. Better position of the volunteers would have a major impact on the formation of safety culture concept and general public awareness of fire safety and risk reduction, and therefore the security of the society as a whole. Volunteer fire departments make a significant contribution to educate young people and prevent catastrophic consequences of fires and natural disasters.Keywords: education, prevention, rescue, volunteer fire departments
Procedia PDF Downloads 2033138 Alcohol Rituals and Active Ageing: A Thematic Analysis of Semi-Structured Interviews with Retirees in the West of Scotland
Authors: Deborah Nicholson, Fiona McCormack, Pete Seaman, Karen Bell
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This paper explores alcohol consumption amongst retirees in the West of Scotland in the context of active and healthy ageing discourses. The public health consequences of alcohol use are well documented and of growing concern to policy makers in Scotland and elsewhere. However, alcohol occupies a prominent position in a range of cultural and social practices and has associated meanings for users related to conviviality, leisure, sociability, and inclusion- features closely tied to active and healthy ageing. These perceived positive and negative meanings place alcohol in an ambiguous and contradictory position in relation to the Scottish Government’s key health policy initiatives aimed at healthy ageing and the reduction of alcohol-related ill-health. This paper explores these positive and negative associations through an examination of the meanings which retirees attach to alcohol and the routines and rituals they develop to navigate wider health concerns. Methods: participants were recruited from the West of Scotland area using a quota sampling design based around gender, age, and socioeconomic position. Forty participants were interviewed using a semi-structured interview schedule and qualitative techniques. The interviews were transcribed and thematic analysis of the data was conducted. Results: Alcohol use amongst retirees in Scotland was widely varied with marked differences noted in terms of gender and age group, but with less clear variance by socioeconomic position. A range of strategies was employed to limit alcohol use by time, context, location and/or volume and these strategies clearly drew on a perception of alcohol use in retirement as potentially more problematic than at earlier stage of life. Thus, the retirees in the sample used these limiting strategies to navigate the positive and negative meanings they attached to alcohol use.Keywords: alcohol, health, retirement, routines
Procedia PDF Downloads 1523137 Using Peer Instruction in Physics of Waves for Pre-Service Science Teacher
Authors: Sumalee Tientongdee
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In this study, it was aimed to investigate Physics achievement of the pre-service science teacher studying in general science program at Suan Sunandha Rajabhat University, Bangkok, Thailand. The program has provided the new curriculum that focuses on 21st-century skills development. Active learning approaches are used to teach in all subjects. One of the active learning approaches Peer Instruction, or PI was used in this study to teach physics of waves as a compulsory course. It was conducted in the second semester from January to May of 2017. The concept test was given to evaluate pre-service science teachers’ understanding in concept of waves. Problem-solving assessment form was used to evaluate their problem-solving skill. The results indicated that after they had learned through Peer Instruction in physics of waves course, their concepts in physics of waves was significantly higher at 0.05 confident levels. Their problem-solving skill from the whole class was at the highest level. Based on the group interview on the opinions of using Peer Instruction in Physics class, they mostly felt that it was very useful and helping them understand more about physics, especially for female students.Keywords: peer instruction, physics of waves, pre-service science teacher, Suan Sunandha Rajabhat university
Procedia PDF Downloads 3483136 Hierarchical Zeolites as Potential Carriers of Curcumin
Authors: Ewelina Musielak, Agnieszka Feliczak-Guzik, Izabela Nowak
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Based on the latest data, it is expected that the substances of therapeutic interest used will be as natural as possible. Therefore, active substances with the highest possible efficacy and low toxicity are sought. Among natural substances with therapeutic effects, those of plant origin stand out. Curcumin isolated from the Curcuma longa plant has proven to be particularly important from a medical point of view. Due to its ability to regulate many important transcription factors, cytokines, and protein kinases, curcumin has found use as an anti-inflammatory, antioxidant, antiproliferative, antiangiogenic, and anticancer agent. The unfavorable properties of curcumin, such as low solubility, poor bioavailability, and rapid degradation under neutral or alkaline pH conditions, limit its clinical application. These problems can be solved by combining curcumin with suitable carriers such as hierarchical zeolites. This is a new class of materials that exhibit several advantages. Hierarchical zeolites used as drug carriers enable delayed release of the active ingredient and promote drug transport to the desired tissues and organs. In addition, hierarchical zeolites play an important role in regulating micronutrient levels in the body and have been used successfully in cancer diagnosis and therapy. To apply curcumin to hierarchical zeolites synthesized from commercial FAU zeolite, solutions containing curcumin, carrier and acetone were prepared. The prepared mixtures were then stirred on a magnetic stirrer for 24 h at room temperature. The curcumin-filled hierarchical zeolites were drained into a glass funnel, where they were washed three times with acetone and distilled water, after which the obtained material was air-dried until completely dry. In addition, the effect of piperine addition to zeolite carrier containing a sufficient amount of curcumin was studied. The resulting products were weighed and the percentage of pure curcumin in the hierarchical zeolite was calculated. All the synthesized materials were characterized by several techniques: elemental analysis, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, Fourier transform infrared (FT-IR), N2 adsorption, and X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The aim of the presented study was to improve the biological activity of curcumin by applying it to hierarchical zeolites based on FAU zeolite. The results showed that the loading efficiency of curcumin into hierarchical zeolites based on commercial FAU-type zeolite is enhanced by modifying the zeolite carrier itself. The hierarchical zeolites proved to be very good and efficient carriers of plant-derived active ingredients such as curcumin.Keywords: carriers of active substances, curcumin, hierarchical zeolites, incorporation
Procedia PDF Downloads 983135 Complex Learning Tasks and Their Impact on Cognitive Engagement for Undergraduate Engineering Students
Authors: Anastassis Kozanitis, Diane Leduc, Alain Stockless
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This paper presents preliminary results from a two-year funded research program looking to analyze and understand the relationship between high cognitive engagement, higher order cognitive processes employed in situations of complex learning tasks, and the use of active learning pedagogies in engineering undergraduate programs. A mixed method approach was used to gauge student engagement and their cognitive processes when accomplishing complex tasks. Quantitative data collected from the self-report cognitive engagement scale shows that deep learning approach is positively correlated with high levels of complex learning tasks and the level of student engagement, in the context of classroom active learning pedagogies. Qualitative analyses of in depth face-to-face interviews reveal insights into the mechanisms influencing students’ cognitive processes when confronted with open-ended problem resolution. Findings also support evidence that students will adjust their level of cognitive engagement according to the specific didactic environment.Keywords: cognitive engagement, deep and shallow strategies, engineering programs, higher order cognitive processes
Procedia PDF Downloads 3243134 Comparative Transcriptome Profiling of Low Light Tolerant and Sensitive Rice Varieties Induced by Low Light Stress at Active Tillering Stage
Authors: Darshan Panda, Lambodar Behera, M. J. Baig, Sudhanshu Sekhar
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Low light intensity is a significant limitation for grain yield and quality in rice. However, yield is not significantly reduced in low-light tolerant rice varieties. The work, therefore, planned for comparative transcriptome profiling under low light stress to decipher the genes involved and molecular mechanism of low light tolerance in rice. At the active tillering stage, 50% low light exposure for one day, three days, and five days were given to Swarnaprabha (low light tolerant) and IR8 (low light sensitive) rice varieties. Illumina (HiSeq) platform was used for transcriptome sequencing. A total of 6,652 and 12,042 genes were differentially expressed due to low light intensity in Swarnaprabha and IR8, respectively, as compared to control. CAB, LRP, SBPase, MT15, TF PCL1, and Photosystem I & II complex related gene expressions were mostly increased in Swarnaprabha upon the longer duration of low light exposure, which was not found in IR8 as compared to control. Their expressions were validated by qRT-PCR. The overall study suggested that the maintenance of grain yield in the tolerant variety under low light might be the result of accelerated expression of the genes, which enable the plant to keep the photosynthetic processes moving at the same pace even under low light.Keywords: rice, low light, photosynthesis, yield
Procedia PDF Downloads 1973133 Real-Time Hybrid Simulation for a Tuned Liquid Column Damper Implementation
Authors: Carlos Riascos, Peter Thomson
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Real-time hybrid simulation (RTHS) is a modern cyber-physical technique used for the experimental evaluation of complex systems, that treats the system components with predictable behavior as a numerical substructure and the components that are difficult to model as an experimental substructure. Therefore it is an attractive method for evaluation of the response of civil structures under earthquake, wind and anthropic loads. Another practical application of RTHS is the evaluation of control systems, as these devices are often nonlinear and their characterization is an important step in the design of controllers with the desired performance. In this paper, the response of three-story shear frame controlled by a tuned liquid column damper (TLCD) and subject to base excitation is considered. Both passive and semi-active control strategies were implemented and are compared. While the passive TLCD achieved a reduction of 50% in the acceleration response of the main structure in comparison with the structure without control, the semi-active TLCD achieved a reduction of 70%, and was robust to variations in the dynamic properties of the main structure. In addition, a RTHS was implemented with the main structure modeled as a linear, time-invariant (LTI) system through a state space representation and the TLCD, with both control strategies, was evaluated on a shake table that reproduced the displacement of the virtual structure. Current assessment measures for RTHS were used to quantify the performance with parameters such as generalized amplitude, equivalent time delay between the target and measured displacement of the shake table, and energy error using the measured force, and prove that the RTHS described in this paper is an accurate method for the experimental evaluation of structural control systems.Keywords: structural control, hybrid simulation, tuned liquid column damper, semi-active sontrol strategy
Procedia PDF Downloads 2993132 Synthesis, Inhibitory Activity, and Molecular Modelling of 2-Hydroxy-3-Oxo-3-Phenylpropionate Derivatives as HIV-1-Integrase Inhibitors
Authors: O. J. Jesumoroti, Faridoon, R. Klein, K. A. Iobb, D. Mnkadhla, H. C. Hoppe, P. T. Kaye
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The 1, 3-aryl diketo acids (DKA) based agents represent an important class of HIV integrase (IN) strand transfer inhibitors. In other to study the chelating role of the divalent metal ion in the inhibition of IN strand transfer, we designed and synthesized a series of 2-hydroxy-3-oxo-3-phenyl propionate derivatives with the notion that such compounds could interact with the divalent ion in the active site of IN. The synthetic sequence to the desired compounds involves the concept of Doebner knoevenagel condensation, Fischer esterification and ketohydroxylation using neuclophilic re-oxidant; compounds were characterized by their IR, IHNMR, 13CNMR, HRMS spectroscopic data and melting point determination. Also, molecular docking was employed in this study and it was revealed that there is interaction with the active site of the enzyme. However, there is disparity in the corresponding anti-HIV activity determined by the experimental bioassay. These compounds lack potency at low micromolar concentration when compared to the results of the docking studies. Nevertheless, the results of the study suggest modification of the aryl ring with one or two hydroxyl groups to improve the inhibitory activity.Keywords: anti-HIV-1 integrase, ketohydroxylation, molecular docking, propionate derivatives
Procedia PDF Downloads 1953131 Genetic Improvement of Centella asiatica (Linn.) Urban. For Therapeutically Active Compounds
Authors: Dalave S. C., S. G. Auti, B. J. Apparao
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Centella asiatica (L) Urban, commonly known as Brahmi and Mandookaparni is a valuable medicinal plant highly valued for its asiaticoside and madecassoside. It is widely used in Ayurveda and Unani systems of medicine. Attempts are made in the present investigation to improve the genotype of Centella plant that can yield higher amount of the therapeutically active compounds viz., asiaticosides and madecassosides, employing techniques of polyploidy breeding. Young developing shoots of Centella were treated with different concentrations of colchicine for varying time intervals. 0.4 % colchicine for 6 hours duration at room temperature was effective in inducing autopolyploidy in this plant. The colchicine treated plants were allowed to reproduce vegetatively for several generations in a polyhouse. The colchicine treated plants showed significant increase in plant size, fresh & dry weights, vigorous growth, broad leaves and double the number of chromosomes. HPTLC analysis of dried leaves of control and polyploid plants, even after 9th generations, revealed that the tetraploids synthesized at two times more asiaticoside and madecassoside, as compared to control, untreated diploid plants.Keywords: Centella asiatica, polyploidy, asiaticosides, madecassoside, HPTLC
Procedia PDF Downloads 2463130 Civic Participation as a Promoter of Active Ageing in Europe
Authors: Andrea Vega-Tinoco, Ana I. Gil-Lacruz, Marta Gil-Lacruz
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The main objective of this research is to acknowledge whether civic participation affects the well-being of the elderly, thus being a key activity of active aging. It is also of interest to recognize any differences among genders, generational cohorts or country of residence. If a positive relationship is found between civic participation and well-being, the actions that promote this participation will benefit the quality of life of senior citizens. Otherwise, independent action must be taken in the improvement of social and human capital. The sample consists of approximately 50.000 individuals from the European Social Survey (2002-2016). Only individuals born before 1965 in 15 European countries were considered. The sample was distributed according to gender, year of birth, country, level of studies and ESS wave to form pseudo-panel data cohorts, leaving a total of 1.318 observations. The data were analyzed through a Cross-Lagged Model using Fixed-Effects. A bidirectional association is observed between the civic participation and well-being variables. However, participating in the past seems to have a higher impact on today’s health, happiness and life satisfaction than the other way around. Furthermore, 26% of the respondents expressed to be satisfied with their life, 27% to be happy and 57% to have good health. On the other hand, 49% have participated civically in the last year, being the most common activities: signing petitions, boycotting products and volunteer work in non-political organizations. A slight trend of BabyBoomers and men towards greater participation can be observed, as well as a higher impact of this participation on their well-being. In addition, international differences exhibit a stronger relation for Nordic, East European and Mediterranean countries. The given results support the hypothesis that civic participation is a promoter of well-being for the elderly. This paper positively highlights the activity of involving in political and non-political organizations, as well as wearing badges. At any rate, almost all forms of civic participation show a positive relationship with well-being and should therefore be promoted, although differences between countries must be taken into consideration.Keywords: active aging, civic participation, Europe, well-being
Procedia PDF Downloads 833129 Active Learning Role on Strategic I-Map Thinking in Developing Reasoning Thinking and the Intrinsic-Motivation Orientation
Authors: Khaled Alotaibi
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This paper deals with developing reasoning thinking and the intrinsic-extrinsic motivation for learning, and enhancing the academic achievement of a sample of students at Teachers' College in King Saud University. The study sample included 58 students who were divided randomly into two groups; one was an experimental group with 20 students and the other was a control group with 22 students. The following tools were used: e-courses by using I-map, Reasoning Thinking Tes, questionnaire to measure the intrinsic-extrinsic motivation for learning and an academic achievement test. Experimental group was taught using e-courses by using I-map, while the control group was taught by using traditional education. The results showed that: - There were no statistically significant differences between the experimental group and the control group in Reasoning thinking skills. - There were statistically significant differences between the experimental group and the control group in the intrinsic-extrinsic motivation for learning in favor of the experimental group. - There were statistically significant differences between the experimental group and the control group in academic achievement in favor of the experimental group.Keywords: reasoning, thinking, intrinsic motivation, active learning
Procedia PDF Downloads 4193128 Surfactant-Free O/W-Emulsion as Drug Delivery System
Authors: M. Kumpugdee-Vollrath, J.-P. Krause, S. Bürk
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Most of the drugs used for pharmaceutical purposes are poorly water-soluble drugs. About 40% of all newly discovered drugs are lipophilic and the numbers of lipophilic drugs seem to increase more and more. Drug delivery systems such as nanoparticles, micelles or liposomes are applied to improve their solubility and thus their bioavailability. Besides various techniques of solubilization, oil-in-water emulsions are often used to incorporate lipophilic drugs into the oil phase. To stabilize emulsions surface active substances (surfactants) are generally used. An alternative method to avoid the application of surfactants was of great interest. One possibility is to develop O/W-emulsion without any addition of surface active agents or the so called “surfactant-free emulsion or SFE”. The aim of this study was to develop and characterize SFE as a drug carrier by varying the production conditions. Lidocaine base was used as a model drug. The injection method was developed. Effects of ultrasound as well as of temperature on the properties of the emulsion were studied. Particle sizes and release were determined. The long-term stability up to 30 days was performed. The results showed that the surfactant-free O/W emulsions with pharmaceutical oil as drug carrier can be produced.Keywords: emulsion, lidocaine, Miglyol, size, surfactant, light scattering, release, injection, ultrasound, stability
Procedia PDF Downloads 4883127 Synthesis, Characterization, and Biological Evaluation of 1,3,4-Mercaptooxadiazole Ether Derivatives Analogs as Antioxidant, Cytotoxic, and Molecular Docking Studies
Authors: Desta Gebretekle Shiferaw, Balakrishna Kalluraya
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Oxadiazoles and their derivatives with thioether functionalities represent a new and exciting class of physiologically active heterocyclic compounds. Several molecules with these moieties play a vital role in pharmaceuticals because of their diverse biological activities. This paper describes a new class of 1,3,4- oxadiazole-2-thioethers with acetophenone, coumarin, and N-phenyl acetamide residues (S-alkylation), with the hope that the addition of various biologically active molecules will have a synergistic effect on anticancer activity. The structure of the synthesized title compounds was determined by the combined methods of IR, proton-NMR, carbon-13-NMR, and mass spectrometry. Further, all the newly prepared molecules were assessed against their antioxidant activity. Furthermore, four compounds were assessed for their molecular docking interactions and cytotoxicity activity. The synthesized derivatives have shown moderate antioxidant activity compared to the standard BHA. The IC50 of the tilted molecules (11b, 11c, 13b, and 14b) observed for in vitro anti-cancer activities were 11.20, 15.73, 59.61, and 27.66 g/ml at 72-hour treatment time against the A549 cell lines, respectively. The tested compounds' biological evaluation showed that 11b is the most effective molecule in the series.Keywords: antioxidant activity, cytotoxicity activity, molecular docking, 1, 3, 4-Oxadiazole-2 thioether derivatives
Procedia PDF Downloads 903126 Ternary Organic Blend for Semitransparent Solar Cells with Enhanced Short Circuit Current Density
Authors: Mohammed Makha, Jakob Heier, Frank Nüesch, Roland Hany
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Organic solar cells (OSCs) have made rapid progress and currently achieve power conversion efficiencies (PCE) of over 10%. OSCs have several merits over other direct light-to-electricity generating cells and can be processed at low cost from solution on flexible substrates over large areas. Moreover, combining organic semiconductors with transparent and conductive electrodes allows for the fabrication of semitransparent OSCs (SM-OSCs). For SM-OSCs the challenge is to achieve a high average visible transmission (AVT) while maintaining a high short circuit current (Jsc). Typically, Jsc of SM-OSCs is smaller than when using an opaque metal top electrode. This is because the non-absorbed light during the first transit through the active layer and the transparent electrode is forward-transmitted out of the device. Recently, OSCs using a ternary blend of organic materials have received attention. This strategy was pursued to extend the light harvesting over the visible range. However, it is a general challenge to manipulate the performance of ternary OSCs in a predictable way, because many key factors affect the charge generation and extraction in ternary solar cells. Consequently, the device performance is affected by the compatibility between the blend components and the resulting film morphology, the energy levels and bandgaps, the concentration of the guest material and its location in the active layer. In this work, we report on a solvent-free lamination process for the fabrication of efficient and semitransparent ternary blend OSCs. The ternary blend was composed of PC70BM and the electron donors PBDTTT-C and an NIR cyanine absorbing dye (Cy7T). Using an opaque metal top electrode, a PCE of 6% was achieved for the optimized binary polymer: fullerene blend (AVT = 56%). However, the PCE dropped to ~2% when decreasing (to 30 nm) the active film thickness to increase the AVT value (75%). Therefore we resorted to the ternary blend and measured for non-transparent cells a PCE of 5.5% when using an active polymer: dye: fullerene (0.7: 0.3: 1.5 wt:wt:wt) film of 95 nm thickness (AVT = 65% when omitting the top electrode). In a second step, the optimized ternary blend was used of the fabrication of SM-OSCs. We used a plastic/metal substrate with a light transmission of over 90% as a transparent electrode that was applied via a lamination process. The interfacial layer between the active layer and the top electrode was optimized in order to improve the charge collection and the contact with the laminated top electrode. We demonstrated a PCE of 3% with AVT of 51%. The parameter space for ternary OSCs is large and it is difficult to find the best concentration ratios by trial and error. A rational approach for device optimization is the construction of a ternary blend phase diagram. We discuss our attempts to construct such a phase diagram for the PBDTTT-C: Cy7T: PC70BM system via a combination of using selective Cy7T selective solvents and atomic force microscopy. From the ternary diagram suitable morphologies for efficient light-to-current conversion can be identified. We compare experimental OSC data with these predictions.Keywords: organic photovoltaics, ternary phase diagram, ternary organic solar cells, transparent solar cell, lamination
Procedia PDF Downloads 2643125 A General Framework for Knowledge Discovery from Echocardiographic and Natural Images
Authors: S. Nandagopalan, N. Pradeep
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The aim of this paper is to propose a general framework for storing, analyzing, and extracting knowledge from two-dimensional echocardiographic images, color Doppler images, non-medical images, and general data sets. A number of high performance data mining algorithms have been used to carry out this task. Our framework encompasses four layers namely physical storage, object identification, knowledge discovery, user level. Techniques such as active contour model to identify the cardiac chambers, pixel classification to segment the color Doppler echo image, universal model for image retrieval, Bayesian method for classification, parallel algorithms for image segmentation, etc., were employed. Using the feature vector database that have been efficiently constructed, one can perform various data mining tasks like clustering, classification, etc. with efficient algorithms along with image mining given a query image. All these facilities are included in the framework that is supported by state-of-the-art user interface (UI). The algorithms were tested with actual patient data and Coral image database and the results show that their performance is better than the results reported already.Keywords: active contour, Bayesian, echocardiographic image, feature vector
Procedia PDF Downloads 4453124 Portfolio Selection with Active Risk Monitoring
Authors: Marc S. Paolella, Pawel Polak
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The paper proposes a framework for large-scale portfolio optimization which accounts for all the major stylized facts of multivariate financial returns, including volatility clustering, dynamics in the dependency structure, asymmetry, heavy tails, and non-ellipticity. It introduces a so-called risk fear portfolio strategy which combines portfolio optimization with active risk monitoring. The former selects optimal portfolio weights. The latter, independently, initiates market exit in case of excessive risks. The strategy agrees with the stylized fact of stock market major sell-offs during the initial stage of market downturns. The advantages of the new framework are illustrated with an extensive empirical study. It leads to superior multivariate density and Value-at-Risk forecasting, and better portfolio performance. The proposed risk fear portfolio strategy outperforms various competing types of optimal portfolios, even in the presence of conservative transaction costs and frequent rebalancing. The risk monitoring of the optimal portfolio can serve as an early warning system against large market risks. In particular, the new strategy avoids all the losses during the 2008 financial crisis, and it profits from the subsequent market recovery.Keywords: comfort, financial crises, portfolio optimization, risk monitoring
Procedia PDF Downloads 5253123 Study on Horizontal Ecological Compensation Mechanism in Yangtze River Economic Belt Basin: Based on Evolutionary Game Analysis and Water Quality and Quantity Model
Authors: Tingyu Zhang
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The horizontal ecological compensation (HEC) mechanism is the key to stimulating the active participation of the whole basin in ecological protection. In this paper, we construct an evolutionary model for HEC in the Yangtze River Economic Belt (YREB) basin with the introduction of the central government constraint and incentive mechanism (CGCIM) and explore the conditions for the realization of a (Protection and compensation) strategy that meets the social expectations. Further, the water quality-water quantity model is utilized to measure the HEC amount with the characteristic factual data of the YREB in 2020-2022. The results show that the stability of the evolutionary game model of upstream and downstream governments in the YREB is closely related to the CGCIM. If (Protection Compensation) is to be realized as the only evolutionary stable strategy of the evolutionary game system composed of upstream and downstream governments, it is necessary for the CGCIM to satisfy that the sum of the incentives for the protection side and its unilateral or bilateral constraints is greater than twice the input cost of the active strategy, and the sum of the incentives for the compensation side and its unilateral or bilateral constraints is greater than the amount of ecological compensation that needs to be paid by it when it adopts the active strategy. At this point, the total amount of HEC that the downstream government should give to the upstream government of the YREB is 2856.7 million yuan in 2020, 5782.1 million yuan in 2021, and 23166.7 million yuan in 2022. The results of the study can provide a reference for promoting the improvement and refinement of the HEC mechanism in the YREB.Keywords: horizontal ecological compensation, Yangtze river economic belt, evolutionary game analysis, water quality and quantity model research on territorial ecological restoration in Mianzhu city, Sichuan, under the dual evaluation framework
Procedia PDF Downloads 503122 Tetra Butyl Ammonium Cyanate Mediated Selective Synthesis of Sulfonyltriuret and Their Investigation towards Trypsin Protease Modulation
Authors: Amarjyoti Das Mahapatra, Umesh Kumar, Bhaskar Datta
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A pseudo peptide can mimic the biological or structural properties of natural peptides. They have become an increasing attention in medicinal chemistry because of their interesting advantages like more bioavailability and less biodegradation than compare to the physiologically active native peptides which increase their therapeutic applications. Many biologically active compounds contain urea as functional groups, and they have improved pharmacokinetic properties because of their bioavailability and metabolic stability. Recently we have reported a single-step synthesis of sulfonyl urea and sulfonyltriuret from sulfonyl chloride and sodium cyanate. But the yield of sulfonyltriuret was less around 40-60% because of the formation of other products like sulfonamide and sulfonylureas. In the present work, we mainly focused on the selective synthesis of sulfonyltriuret using tetrabutylammonium cyanate and sulfonyl chloride. More precisely, we are interested in the controlled synthesis of oligomeric urea mainly sulfonyltriuret as a new class of pseudo peptide and their application as protease modulators. The distinctive architecture of these molecules in the form of their pseudo-peptide backbone offers promise as a potential pharmacophore. The synthesized molecules have been screened on trypsin enzyme, and we observed that these molecules are the efficient modulator of trypsin enzyme.Keywords: pseudo peptide, pharmacophore, sulfonyltriuret, trypsin
Procedia PDF Downloads 1673121 Factors Affecting Physical Activity among University Students of Different Fields of Study
Authors: Robert Dutkiewicz, Monika Szpringer, Mariola Wojciechowska
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Physical activity is one of the factors greatly influencing healthy lifestyle. The recent research into physical activity of the Polish society reveals that contribution of physical culture to healthy lifestyle is insufficient. Students, regardless of age, spend most of free-time in front of a TV or computer. The research attempted to identify the level of physical activity and healthy lifestyle among students of medical sciences and other students doing their teaching degrees. The findings of physical activity research conducted in 2014, which covered 364 students of medical sciences and future teachers from the University of Jan Kochanowski in Kielce were analysed. The research involved the method of diagnostic survey based on a questionnaire. It attempted to establish to what extent such factors as the field of studies, the place of residence and BMI affect students’ physical activity. Empirical material was analysed by means of SPSS/PC, the leading statistical software. The field of study significantly influences physical activity of the respondents. The students of physiotherapy and public health tend to be more physically active than students of biology and geography: 46.8% students of geography and 51.8 % biology students seldom take up physical activity. Obesity and overweight are currently serious problems of university students: 6.6% of them are obese and 19% overweight. It is alarming that these students are not willing to find ways to be more physically active. Most of the obese and overweight respondents study biology or geography and live in a rural area. Unequal chances in terms of youth physical culture are determined by the differences between rural and urban environments. Young people living in rural areas are less physically active, particularly in terms of the frequency and the amount of time devoted to physical activity. This is caused by poor infrastructure to perform physical activity, the lack of or limited number of sports clubs and centres. It is thought-provoking that most of the students claim that they do not have enough time to do sports or other activities, but at the same time they spend a lot of time at a computer or watching TV.Keywords: BMI, healthy lifestyle, sports activity, students
Procedia PDF Downloads 5003120 Study of Self-Assembled Photocatalyst by Metal-Terpyridine Interactions in Polymer Network
Authors: Dong-Cheol Jeong, Jookyung Lee, Yu Hyeon Ro, Changsik Song
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The design and synthesis of photo-active polymeric systems are important in regard to solar energy harvesting and utilization. In this study, we synthesized photo-active polymer, thin films, and polymer gel via iterative self-assembly using reversible metal-terpyridine (M-tpy) interactions. The photocurrent generated in the polymeric thin films with Zn(II) was much higher than those of other films. Apparent diffusion rate constant (kapp) was measured for the electron hopping process via potential-step chronoamperometry. As a result, the kapp for the polymeric thin films with Zn(II) was almost two times larger than those with other metal ions. We found that the anodic photocurrents increased with the inclusion of the multi-walled carbon nanotube (MWNT) layer. Inclusion of MWNTs can provide efficient electron transfer pathways. In addition, polymer gel based on interactions between terpyridine and metal ions was shown the photocatalytic activity. Interestingly, in the Mg-terpyridine gel, the reaction rate of benzylamine to imine photo-oxidative coupling was faster than Fe-terpyridine gel because the Mg-terpyridine gel has two steps electron transfer pathway but Fe-terpyridine gel has three steps electron transfer pathway.Keywords: terpyridine, photocatalyst, self-assebly, metal-ligand
Procedia PDF Downloads 3093119 Active Space Debris Removal by Extreme Ultraviolet Radiation
Authors: A. Anandha Selvan, B. Malarvizhi
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In recent year the problem of space debris have become very serious. The mass of the artificial objects in orbit increased quite steadily at the rate of about 145 metric tons annually, leading to a total tally of approximately 7000 metric tons. Now most of space debris object orbiting in LEO region about 97%. The catastrophic collision can be mostly occurred in LEO region, where this collision generate the new debris. Thus, we propose a concept for cleaning the space debris in the region of thermosphere by passing the Extreme Ultraviolet (EUV) radiation to in front of space debris object from the re-orbiter. So in our concept the Extreme Ultraviolet (EUV) radiation will create the thermosphere expansion by reacting with atmospheric gas particles. So the drag is produced in front of the space debris object by thermosphere expansion. This drag force is high enough to slow down the space debris object’s relative velocity. Therefore the space debris object gradually reducing the altitude and finally enter into the earth’s atmosphere. After the first target is removed, the re-orbiter can be goes into next target. This method remove the space debris object without catching debris object. Thus it can be applied to a wide range of debris object without regard to their shapes or rotation. This paper discusses the operation of re-orbiter for removing the space debris in thermosphere region.Keywords: active space debris removal, space debris, LEO, extreme ultraviolet, re-orbiter, thermosphere
Procedia PDF Downloads 4633118 Factors Associated with Self-Reported Pregnancies among Secondary School Teenagers in South Africa: Evidence from General Household Surveys
Authors: Sathiya Susuman Appunni
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Background: This article reviews the self-reported pregnancies among teenage girls currently attending secondary school in South Africa. The study aim is to examine the demographic and socio-economic factors associated with self-reported pregnancies among teenage girls currently attending secondary school in the study area. Data and Methods: Secondary data drawn from the General Household Surveys 2016 and Community Survey 2016 as well as 10 % sample data from the 2011 South African census were used. Bivariate, and Multivariate analyses were carried in order to meet the aims of the study. Results: The independent variable identified was the number of economically active people in the household, which indicated 3.3% in 2011 and 3.6% in 2016 for the household with no economically active member. Among the provinces, Limpopo has been leading by 5.2% of self-reported pregnancies among the girls currently attending secondary school in South Africa. Conclusion: It is recommended that the needs to be special health policies and strategies in place to address this epidemic and such policies need to be targeted to the different needs of teenagers in the different demarcations of the country.Keywords: pregnancy prevalence, demographic, household, teenage girls, socio-economic
Procedia PDF Downloads 1613117 Antibacterial Nanofibrous Film Encapsulated with 4-terpineol/β-cyclodextrin Inclusion Complexes: Relative Humidity-Triggered Release and Shrimp Preservation Application
Authors: Chuanxiang Cheng, Tiantian Min, Jin Yue
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Antimicrobial active packaging enables extensive biological effects to improve food safety. However, the efficacy of antimicrobial packaging hinges on factors including the diffusion rate of the active agent toward the food surface, the initial content in the antimicrobial agent, and the targeted food shelf life. Among the possibilities of antimicrobial packaging design, an interesting approach involves the incorporation of volatile antimicrobial agents into the packaging material. In this case, the necessity for direct contact between the active packaging material and the food surface is mitigated, as the antimicrobial agent exerts its action through the packaging headspace atmosphere towards the food surface. However, it still remains difficult to achieve controlled and precise release of bioactive compounds to the specific target location with required quantity in food packaging applications. Remarkably, the development of stimuli-responsive materials for electrospinning has introduced the possibility of achieving controlled release of active agents under specific conditions, thereby yielding enduring biological effects. Relative humidity (RH) for the storage of food categories such as meat and aquatic products typically exceeds 90%. Consequently, high RH can be used as an abiotic trigger for the release of active agents to prevent microbial growth. Hence, a novel RH - responsive polyvinyl alcohol/chitosan (PVA/CS) composite nanofibrous film incorporated with 4-terpineol/β-cyclodextrin inclusion complexes (4-TA@β-CD ICs) was engineered by electrospinning that can be deposited as a functional packaging materials. The characterization results showed the thermal stability of the films was enhanced after the incorporation due to the hydrogen bonds between ICs and polymers. Remarkably, the 4 wt% 4-TA@β-CD ICs/PVA/CS film exhibited enhanced crystallinity, moderate hydrophilic (Water contact angle of 81.53°), light barrier property (Transparency of 1.96%) and water resistance (Water vapor permeability of 3.17 g mm/m2 h kPa). Moreover, this film also showed optimized mechanical performance with a Young’s modulus of 11.33 MPa, a tensile strength of 19.99 MPa and an elongation at break of 4.44 %. Notably, the antioxidant and antibacterial properties of this packaging material were significantly improved. The film demonstrated the half-inhibitory concentrations (IC50) values of 87.74% and 85.11% for scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic) (ABTS) free radicals, respectively, in addition to an inhibition efficiency of 65% against Shewanella putrefaciens, the characteristic bacteria in aquatic products. Most importantly, the film achieved controlled release of 4-TA under high 98% RH by inducing the plasticization of polymers caused by water molecules, swelling of polymer chains, and destruction of hydrogen bonds within the cyclodextrin inclusion complex. Consequently, low relative humidity is suitable for the preservation of nanofibrous film, while high humidity conditions typical in fresh food packaging environments effectively stimulated the release of active compounds in the film. This film with a long-term antimicrobial effect successfully extended the shelf life of Litopenaeus vannamei shrimp to 7 days at 4 °C. This attractive design could pave the way for the development of new food packaging materials.Keywords: controlled release, electrospinning, nanofibrous film, relative humidity–responsive, shrimp preservation
Procedia PDF Downloads 713116 Mapping the Future: Participatory Master Planning for Pioneer Village Tourism in Cibubuan, Sumedang
Authors: Sarojini Imran, Riza Firmansyah, Aula Ramadhan, Chudamul Furqon, Achfriyatama Oktariflandi
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This article delves into the participatory approach in formulating a master plan for the development of pioneer village tourism in Cibubuan, Sumedang. We explore the process of participatory mapping that involves the active participation of the local community in planning and envisioning the future of village tourism. This research considers the positive impact that arises when the community takes an active role in designing a master plan that benefits the local economy while preserving culture and the environment. The results of this research reveal that the participatory approach can create a more accurate and community-responsive mapping that aligns with the aspirations of the people in Cibubuan Village. It also provides a deep insight into how community-developed mapping can guide the development of sustainable tourism. By offering a deeper understanding of the participatory role in village tourism development planning, this article provides essential insights for stakeholders and researchers in this field. We hope this article will inspire more communities to adopt a participatory approach in planning the future of their village tourism.Keywords: participatory masterplan, pioneer village tourism, sustainable tourism, community engagement, Cibubuan Village
Procedia PDF Downloads 683115 Energy-Dense and High-Power Li-Cl₂/I₂ Batteries by Reversible Chemical Bonds
Authors: Pei Li, Chunyi Zhi
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Conversion-type lithium-ion batteries show great potential as high-energy-density, low-cost and sustainable alternatives to current transition-metal-based intercalation cells. Li-Cl₂/Li⁻I₂ conversion batteries, based on anionic redox reactions of Cl⁻/Cl⁰ or I⁻/I⁰, are highly attractive due to their superior voltage and capacity. However, a redox-active and reversible chlorine cathode has not been developed in organic electrolytes. And thermodynamic instability and shuttling issues of iodine cathodes have plagued the active iodine loading, capacity retention and cyclability. By reversible chemical bonds, we develop reversible chlorine redox reactions in organic electrolytes with interhalogen bonds between I and Cl for Li-I₂ batteries and develop a highly thermally stable I/I₃--bonded organic salts with iodine content up to 80% as cathode materials for the rechargeable Li-I₂ batteries. The demonstration of reversible chemical bonds enabled rechargeable Li-halogen batteries opens a new avenue to develop halogen compound cathodes.Keywords: conversion-type, chlorine, halogen cathode, high energy density, iodine, interhalogen bond, lithium-ion batteries
Procedia PDF Downloads 843114 Geophysical Contribution to Reveal the Subsurface Structural Setting Using Gravity, Seismic and Seismological Data in the Chott Belts, Southern Atlas of Tunisia
Authors: Nesrine Frifita, Mohamed Gharbi, Kevin Mickus
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Physical methods based on gravity, seismic and seismological data were adopted to clarify the relationship between the distribution of seismicity and the crustal deformations under the chott belts and surrounding regions, in southern atlas of Tunisia. Gafsa and its surrounding were described as a moderate seismic zone, and the fault of Gafsa is one of most seismically active faults in Tunisia in general, and in the southern Atlas in particularly. The present work aims to prove a logical relationship between the distribution of seismicity and deformations which strongly related to thickness and density variations within the basement and sedimentary cover along the study area, through several physical methods; gravity, seismic and seismological data were interpreted to calculate physical propriety of the subsurface rocks, the depth and geometry of active faults and causatives bodies. Findings show that depths variation and mixed thin and thick skinned structural style characterizing the chott belts explain the moderate seismicity in the study area.Keywords: potential fields, seismicity, Southern Atlas, Tunisia
Procedia PDF Downloads 1133113 Biofungicides in Nursery Production
Authors: Miroslava Markovic, Snezana Rajkovic, Ljubinko Rakonjac, Aleksandar Lucic
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Oak powdery mildew is a serious problem on seedlings in nurseries as well as on naturally and artificially introduced progeny. The experiments were set on oak seedlings in two nurseries located in Central Serbia, where control of oak powdery mildew Microsphaera alphitoides Griff. et Maubl. had been conducted through alternative protection measures by means of various dosages of AQ-10 biofungicide, with and without added polymer (which has so far never been used in this country for control of oak powdery mildew). Simultaneous testing was conducted on the efficiency of a chemical sulphur-based preparation (used in this area for many years as a measure of suppression of powdery mildews, without the possibility of developing resistance of the pathogen to the active matter). To date, the Republic of Serbia has registered no fungicides for suppression of pathogens in the forest ecosystems. In order to introduce proper use of new disease-fighting agents into a country, certain relevant principles, requirements and criteria prescribed by the Forest Stewardship Council (FSC) must be observed, primarily with respect to measures of assessment and mitigation of risks, the list of dangerous and highly dangerous pesticides with the possibility of alternative protection. One of the main goals of the research was adjustment of the protective measures to the FSC policy through selection of eco-toxicologically favourable fungicides, given the fact that only preparations named on the list of permitted active matters are approved for use in certified forests. The results of the research have demonstrated that AQ-10 biofungicide can be used as a part of integrated disease management programmes as an alternative, through application of several treatments during vegetation and combination with other active matters registered for these purposes, so as to curtail the use of standard fungicides for control of powdery mildews on oak seedlings in nurseries. The best results in suppression of oak powdery mildew were attained through use of AQ-10 biofungicide (dose 50 or 70g/ha) with added polymer Nu Film-17 (dose 1.0 or 1.5 l/ha). If the treatment is applied at the appropriate time, even fewer number of treatments and smaller doses will be just as efficient.Keywords: oak powdery mildew, biofungicides, polymers, Microsphaera alphitoides
Procedia PDF Downloads 3753112 A Portable Cognitive Tool for Engagement Level and Activity Identification
Authors: Terry Teo, Sun Woh Lye, Yufei Li, Zainuddin Zakaria
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Wearable devices such as Electroencephalography (EEG) hold immense potential in the monitoring and assessment of a person’s task engagement. This is especially so in remote or online sites. Research into its use in measuring an individual's cognitive state while performing task activities is therefore expected to increase. Despite the growing number of EEG research into brain functioning activities of a person, key challenges remain in adopting EEG for real-time operations. These include limited portability, long preparation time, high number of channel dimensionality, intrusiveness, as well as level of accuracy in acquiring neurological data. This paper proposes an approach using a 4-6 EEG channels to determine the cognitive states of a subject when undertaking a set of passive and active monitoring tasks of a subject. Air traffic controller (ATC) dynamic-tasks are used as a proxy. The work found that when using the channel reduction and identifier algorithm, good trend adherence of 89.1% can be obtained between a commercially available BCI 14 channel Emotiv EPOC+ EEG headset and that of a carefully selected set of reduced 4-6 channels. The approach can also identify different levels of engagement activities ranging from general monitoring ad hoc and repeated active monitoring activities involving information search, extraction, and memory activities.Keywords: assessment, neurophysiology, monitoring, EEG
Procedia PDF Downloads 763111 A General Framework for Knowledge Discovery Using High Performance Machine Learning Algorithms
Authors: S. Nandagopalan, N. Pradeep
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The aim of this paper is to propose a general framework for storing, analyzing, and extracting knowledge from two-dimensional echocardiographic images, color Doppler images, non-medical images, and general data sets. A number of high performance data mining algorithms have been used to carry out this task. Our framework encompasses four layers namely physical storage, object identification, knowledge discovery, user level. Techniques such as active contour model to identify the cardiac chambers, pixel classification to segment the color Doppler echo image, universal model for image retrieval, Bayesian method for classification, parallel algorithms for image segmentation, etc., were employed. Using the feature vector database that have been efficiently constructed, one can perform various data mining tasks like clustering, classification, etc. with efficient algorithms along with image mining given a query image. All these facilities are included in the framework that is supported by state-of-the-art user interface (UI). The algorithms were tested with actual patient data and Coral image database and the results show that their performance is better than the results reported already.Keywords: active contour, bayesian, echocardiographic image, feature vector
Procedia PDF Downloads 420