Search results for: colloidal synthesis

Authors: Shaun G. Abbott, Rebecca C. Reynolds, James B. Etter, John B. F. de Wit

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The benefits of physical activity (PA) on health are well documented. Low socioeconomic status (SES) is associated with poor health, with PA a suggested mediator. Pedometers and accelerometers offer an effective behavior change tool to increase PA levels. While the role of pedometer and accelerometer use in increasing PA is recognized in many populations, little is known in low-SES groups. We are aiming to assess the effectiveness of pedometer- and accelerometer-based interventions for increasing PA step count and improving subsequent health outcomes among low-SES groups of high-income countries. Medline, Embase, PsycINFO, CENTRAL and SportDiscus databases were searched to identify articles published before 10th July, 2015; using search terms developed from previous systematic reviews. Inclusion criteria are: low-SES participants classified by income, geography, education, occupation or ethnicity; study duration minimum 4 weeks; an intervention and control group; wearing of an unsealed pedometer or accelerometer to objectively measure PA as step counts per day for the duration of the study. We retrieved 2,142 articles from our database searches, after removal of duplicates. Two investigators independently reviewed titles and abstracts of these articles (50% each) and a combined 20% sample were reviewed to account for inter-assessor variation. We are currently verifying the full texts of 430 articles. Included studies will be critically appraised for risk of bias using guidelines suggested by the Cochrane Public Health Group. Two investigators will extract data concerning the intervention; study design; comparators; steps per day; participants; context and presence or absence of obesity and/or chronic disease. Heterogeneity amongst studies is anticipated, thus a narrative synthesis of data will be conducted with the simplification of selected results into percentage increases from baseline to allow for between-study comparison. Results will be presented at the conference in December if selected.

Keywords: accelerometer, pedometer, physical activity, socioeconomic, step count

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Authors: Hamza I. Isa, Gezina C. H. Ferreira, Jan E. Crafford, Christoffel J. Botha

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Moraea pallida Bak. (yellow tulip) poisoning is the most important plant-induced cardiac glycoside toxicosis in South Africa. Cardiac glycoside poisonings collectively account for about 33 and 10 % mortalities due to plants, in large and small stock respectively, in South Africa. The toxic principle is 1α, 2α-epoxyscillirosidine, a bufadienolide. The aim of the study was to investigate the potential to develop a vaccine against epoxyscillirosidine. Epoxyscillirosidine and the related bufadienolides proscillaridin and bufalin, which are commercially available, were conjugated to the carrier proteins [Hen ovalbumin (OVA), bovine serum albumin (BSA) and keyhole limpet haemocyanin (KLH)], rendering them immunogenic. Adult male New Zealand White rabbits were immunized. In Trials 1 and 2, rabbits (n=6) were, each assigned to two groups. Experimental animals (n=3; n=4) were vaccinated with epoxyscillirosidine-OVA conjugate, while the control (n=3; n=2) were vaccinated with OVA, using Freund’s complete and incomplete and Montanide adjuvants, for Trials 1 and 2, respectively. In Trial 3, rabbits (n=15), randomly allocated to 5 equal groups (I, II, III, IV and V), were vaccinated with proscillaridin-BSA, bufalin-BSA, epoxyscillirosidine-KLH, epoxyscillirosidine-BSA conjugates, and BSA respectively, using Montanide as adjuvant. Vaccination was on Days 0, 21 and 42. Additional vaccinations were done on Day 56 and 63 for Trial 1. Vaccination was by intradermal injection of 0.4 ml of the immunogen (4 mg/ml [Trial 1] and 8 mg/ml for Trials 2 and Trial 3, respectively). Blood was collected pre-vaccination and at 3 week intervals following each vaccination. Antibody response was determined using an indirect ELISA. There was poor immune response associated with the dose (0.4 mg per rabbit) and adjuvant used in Trial 1. Antibodies were synthesized against the conjugate administered in Trial 2. For Trail 3, antibodies against the immunogens were successfully raised in rabbits with epoxyscillirosidine-KLH inducing the highest immune response. The antibodies raised against proscillaridin and bufalin cross-reacted with epoxyscillirosidine when used as antigen in the ELISA. The study successfully demonstrated the synthesis of antibodies against the bufadienolide conjugates administered. The cross-reactivity of proscillaridin and bufalin with epoxyscillirosidine could potentially be utilized as alternative to epoxyscillirosidine in future studies to prevent yellow tulp poisoning by vaccination.

Keywords: antibodies , bufadienolides, cross-reactivity, epoxyscillirosidine, Moraea pallida, poisoning

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Authors: Fuad Abdullah Alatawi

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Microbial infections-based diseases are a significant public health issue around the world, mainly when antibiotic-resistant bacterium types evolve. In this research, we explored the anti-bacterial and anti-cancer potency of iron-oxide (Fe₂O₃) nanoparticles prepared from F. macrocarpa fruit extract. The chemical composition of F. macrocarpa fruit extract was used as a reducing and capping agent for nanoparticles’ synthesis was examined by GC-MS/MS analysis. Then, the prepared nanoparticles were confirmed by various biophysical techniques, including X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Vis Spectroscopy, and Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDAX), and Dynamic Light Scattering (DLS). Also, the antioxidant capacity of fruit extract was determined through 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), Fluorescence Recovery After Photobleaching (FRAP), Superoxide Dismutase (SOD) assays. Furthermore, the cytotoxicity activities of Fe₂O₃ NPs were determined using the (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) (MTT) test on MCF-7 cells. In the antibacterial assay, lethal doses of the Fe₂O₃NPs effectively inhibited the growth of gram-negative and gram-positive bacteria. The surface damage, ROS production, and protein leakage are the antibacterial mechanisms of Fe₂O₃NPs. Concerning antioxidant activity, the fruit extracts of F. macrocarpa had strong antioxidant properties, which were confirmed by DPPH, ABTS, FRAP, and SOD assays. In addition, the F. microcarpa-derived iron oxide nanomaterials greatly reduced the cell viability of (MCF-7). The GC-MS/MS analysis revealed the presence of 25 main bioactive compounds in the F. microcarpa extract. Overall, the finding of this research revealed that F. microcarpa-derived Fe₂O₃ nanoparticles could be employed as an alternative therapeutic agent to cure microbial infection and breast cancer in humans.

Keywords: ficus microcarpa, iron oxide, antibacterial activity, cytotoxicity

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Authors: Pelin Balcik Ercin

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Introduction: ZEB transcription factor family member ZEB2, has a role in epithelial to mesenchymal transition during development and metastasis. The altered circulating extracellular miRNAs expression is observed in diseases, and extracellular miRNAs have an important role in cancer cell microenvironment. In ChIP-Seq study, the expression of miR-2110 was found to be regulated by ZEB2. In this study, the effects of miR2110 on cell proliferation and migration of hepatocellular carcinoma (HCC) cells were examined. Material and Methods: SNU398 cells transfected with mimic miR2110 (20nM) (HMI0375, Sigma-Aldrich) and negative control miR (HMC0002, Sigma-Aldrich). MicroRNA isolation was accomplished with miRVANA isolation kit according to manufacturer instructions. cDNA synthesis was performed expression, respectively, and calibrated with Ct of controls. The real-time quantitative PCR (RT-qPCR) reaction was performed using the TaqMan Fast Advanced Master Mix (Thermo Sci.). Ct values of miR2110 were normalized to miR-186-5p and miR16-5p for the intracellular gene. Cell proliferation analysis was analyzed with the xCELLigence RTCA System. Wound healing assay was analyzed with the ImageJ program and relative fold change calculated. Results: The mimic-miR-2110 transfected SNU398 cells nearly nine-fold (log2) more miR-2110 expressed compared to negative control transfected cells. The mimic-miR-2110 transfected HCC cell proliferation significantly inhibited compared to the negative control cells. Furthermore, miR-2110-SNU398 cell migration capacity was relatively four-fold decreased compared to negative control-miR-SNU398 cells. Conclusion: Our results suggest the miR-2110 inhibited cell proliferation and also miR-2110 negatively affect cell migration compared to control groups in HCC cells. These data suggest the complexity of microRNA EMT transcription factors regulation. These initial results are pointed out the predictive biomarker capacity of miR-2110 in HCC.

Keywords: epithelial to mesenchymal transition, EMT, hepatocellular carcinoma cells, micro-RNA-2110, ZEB2

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Authors: Rachel Fanelwa Ajayi, Anovuyo Jonnas, Emmanuel I. Iwuoha

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Tuberculosis (TB) is an infectious disease caused by the bacterium (Mycobacterium tuberculosis) which has a predilection for lung tissue due to its rich oxygen supply. The mycobacterial cell has a unique innate characteristic which allows it to resist human immune systems and drug treatments; hence, it is one of the most difficult of all bacterial infections to treat, let alone to cure. At the same time, multi-drug resistance TB (MDR-TB) caused by poorly managed TB treatment, is a growing problem and requires the administration of expensive and less effective second line drugs which take much longer treatment duration than fist line drugs. Therefore, to acknowledge the issues of patients falling ill as a result of inappropriate dosing of treatment and inadequate treatment administration, a device with a fast response time coupled with enhanced performance and increased sensitivity is essential. This study involved the synthesis of electroactive platforms for application in the development of nano-biosensors suitable for the appropriate dosing of clinically diagnosed patients by promptly quantifying the levels of the TB drug; Isonaizid. These nano-biosensors systems were developed on gold surfaces using the enzyme N-acetyletransferase 2 coupled to the cysteamine modified poly(8-anilino-1-napthalene sulphonic acid)/zinc oxide nanocomposites. The morphology of ZnO nanoparticles, PANSA/ZnO nano-composite and nano-biosensors platforms were characterized using High-Resolution Transmission Electron Microscopy (HRTEM) and High-Resolution Scanning Electron Microscopy (HRSEM). On the other hand, the elemental composition of the developed nanocomposites and nano-biosensors were studied using Fourier Transform Infra-Red Spectroscopy (FTIR) and Energy Dispersive X-Ray (EDX). The electrochemical studies showed an increase in electron conductivity for the PANSA/ZnO nanocomposite which was an indication that it was suitable as a platform towards biosensor development.

Keywords: N-acetyletransferase 2, isonaizid, tuberculosis, zinc oxide

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Authors: Yi-Chiang Huang, Hsu-Feng Lee, Yu-Chao Tseng, Wen-Yao Huang

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Proton exchange membranes as a key component in fuel cells have been widely studying over the past few decades. As proton exchange, membranes should have some main characteristics, such as good mechanical properties, low oxidative stability and high proton conductivity. In this work, trifluoromethyl groups had been introduced on polymer backbone and phenyl side chain which can provide densely located sulfonic acid group substitution and also promotes solubility, thermal and oxidative stability. Herein, a series of novel sulfonated aromatic hydrocarbon polyelectrolytes was synthesized by polycondensation of 4,4''''-difluoro-3,3''''- bis(trifluoromethyl)-2'',3''-bis(3-(trifluoromethyl)phenyl)-1,1':4',1'':4'',1''':4''',1''''-quinquephenyl with 2'',3''',5'',6''-tetraphenyl-[1,1':4',1'': 4'',1''':4''',1''''-quinquephenyl]-4,4''''-diol and post-sulfonated was through chlorosulfonic acid to given sulfonated polymers (SFC3-X) possessing ion exchange capacities ranging from 1.93, 1.91 and 2.53 mmol/g. ¹H NMR and FT-IR spectroscopy were applied to confirm the structure and composition of sulfonated polymers. The membranes exhibited considerably dimension stability (10-27.8% in length change; 24-56.5% in thickness change) and excellent oxidative stability (weight remain higher than 97%). The mechanical properties of membranes demonstrated good tensile strength on account of the high rigidity multi-phenylated backbone. Young's modulus were ranged 0.65-0.77GPa which is much larger than that of Nafion 211 (0.10GPa). Proton conductivities of membranes ranged from 130 to 240 mS/cm at 80 °C under fully humidified which were comparable or higher than that of Nafion 211 (150 mS/cm). The morphology of membranes was investigated by transmission electron microscopy which demonstrated a clear hydrophilic/hydrophobic phase separation with spherical ionic clusters in the size range of 5-20 nm. The SFC3-1.97 single fuel cell performance demonstrates the maximum power density at 1.08W/cm², and Nafion 211 was 1.24W/cm² as a reference in this work. The result indicated that SFC3-X are good candidates for proton exchange membranes in fuel cell applications. Fuel cell of other membranes is under testing.

Keywords: fuel cells, polyelectrolyte, proton exchange membrane, sulfonated polymers

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Authors: Wadha Alqahtani

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In recent times, polymers have seen a great surge in interest in the field of medicine, particularly chemotherapeutics. One recent innovation is the conversion of polymeric materials into “polymeric nanoparticles”. These nanoparticles can be designed and modified to encapsulate and transport drugs selectively to cancer cells, minimizing collateral damage to surrounding healthy tissues, and improve patient quality of life. In this study, we have synthesized pseudo-branched polyester polymers from bio-based small molecules, including sorbitol, glutaric acid and a propargylic acid derivative to further modify the polymer to make it “click-able" with an azide-modified target ligand. Melt polymerization technique was used for this polymerization reaction, using lipase enzyme catalyst NOVO 435. This reaction was conducted between 90- 95 °C for 72 hours. The polymer samples were collected in 24-hour increments for characterization and to monitor reaction progress. The resulting polymer was purified with the help of methanol dissolving and filtering with filter paper then characterized via NMR, GPC, FTIR, DSC, TGA and MALDI-TOF. Following characterization, these polymers were converted to a polymeric nanoparticle drug delivery system using solvent diffusion method, wherein DiI optical dye and chemotherapeutic drug Taxol can be encapsulated simultaneously. The efficacy of the nanoparticle’s apoptotic effects were analyzed in-vitro by incubation with prostate cancer (LNCaP) and healthy (CHO) cells. MTT assays and fluorescence microscopy were used to assess the cellular uptake and viability of the cells after 24 hours at 37 °C and 5% CO2 atmosphere. Results of the assays and fluorescence imaging confirmed that the nanoparticles were successful in both selectively targeting and inducing apoptosis in 80% of the LNCaP cells within 24 hours without affecting the viability of the CHO cells. These results show the potential of using biodegradable polymers as a vehicle for receptor-specific drug delivery and a potential alternative for traditional systemic chemotherapy. Detailed experimental results will be discussed in the e-poster.

Keywords: chemotherapeutic drug, click chemistry, nanoparticle, prostat cancer

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Authors: Rolivhuwa Bishop Ramagoma1*, Lynn Cairncross1, , Saartjie Roux1

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According to the world health organisation, colon cancer is among the most common cancers diagnosed in both men and women. Specifically, it is the second leading cause of cancer related deaths accounting for over 860 000 deaths worldwide in 2018. Currently, chemotherapy has become an essential component of most cancer treatments. Despite progress in cancer drug development over the previous years, traditional chemotherapeutic drugs still have low selectivity for targeting tumour tissues and are frequently constrained by dose-limiting toxicity. The creation of nanoscale delivery vehicles capable of directly directing treatment into cancer cells has recently caught the interest of researchers. Herein, the development of peptide-functionalized polyethylene glycol gold nanoparticles (Peptide-PEG-AuNPs) as a cellular probe and delivery agent is described, with the higher aim to develop a specific diagnostic prototype and assess their specificity not only against cell lines but primary human cells as well. Gold nanoparticles (AuNPs) were synthesized and stabilized through chemical conjugation. The synthesized AuNPs were characterized, stability in physiological solutions was assessed, their cytotoxicity against colon carcinoma and non-carcinoma skin fibroblasts was also studied. Furthermore, genetic effect through real-time polymerase chain reaction (RT-PCR), localization and uptake, peptide specificity were also determined. In this study, different peptide-AuNPs were found to have preferential toxicity at higher concentrations, as revealed by cell viability assays, however, all AuNPs presented immaculate stability for over 3 months following the method of synthesis. The final obtained peptide-PEG-AuNP conjugates showed good biocompatibility in the presence of high ionic solutions and biological media and good cellular uptake. Formulation of colon cancer specific targeting peptide was successful, additionally, the genes/pathways affected by the treatments were determined through RT-PCR. Primary cells study is still on going with promising results thus far.

Keywords: nanotechnology, cancer, diagnosis, therapeutics, gold nanoparticles.

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Authors: Frida Carrillo Morales, Maria Maricela Carrasco Yépez, Saúl Rojas Hernández

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Naegleria fowleri is the causative agent of primary amebic meningoencephalitis, this disease is acute and fulminant that affects humans. It has been reported that despite the existence of therapeutic options against this disease, its mortality rate is 97%. Therefore, the need arises to have vaccines that confer protection against this disease and, in addition to developing adjuvants to enhance the immune response. In this regard, in our work group, we obtained a peptide designed from the membrane protein MP2CL5 of Naegleria fowleri called Smp145 that was shown to be immunogenic; however, it would be of great importance to enhance its immunological response, being able to co-administer it with a non-toxic adjuvant. Therefore, the objective of this work was to carry out the bioinformatic design of a peptide of the Naegleria fowleri membrane protein MP2CL5 conjugated with a non-toxic modified adjuvant from the native A1 structure of Cholera Toxin. For which different bioinformatics tools were used to obtain a model with a modification in amino acid 61 of the A1 subunit of the CT (CTA1), to which the Smp145 peptide was added and both molecules were joined with a 13-glycine linker. As for the results obtained, the modification in CTA1 bound to the peptide produces a reduction in the toxicity of the molecule in in silico experiments, likewise, the prediction in the binding of Smp145 to the receptor of B cells suggests that the molecule is directed in specifically to the BCR receptor, decreasing its native enzymatic activity. The stereochemical evaluation showed that the generated model has a high number of adequately predicted residues. In the ERRAT test, the confidence with which it is possible to reject regions that exceed the error values was evaluated, in the generated model, a high score was obtained, which determines that the model has a good structural resolution. Therefore, the design of the conjugated peptide in this work will allow us to proceed with its chemical synthesis and subsequently be able to use it in the mouse meningitis protection model caused by N. fowleri.

Keywords: immunology, vaccines, pathogens, infectious disease

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Authors: Shanker Kalakotla, Krishna Mohan Gottumukkala

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Diabetes is a metabolic disorder characterized by hyperglycemia, carbohydrates, altered lipids and proteins metabolism. In recent research nanotechnology is a blazing field for the researchers; latterly there has been prodigious excitement in the nanomedicine and nano pharmacological area for the study of silver nanoparticles synthesis using natural products. Biological methods have been used to synthesize silver nanoparticles in presence of medicinally active antidiabetic plants, and this intention made us assess the biologically synthesized silver nanoparticles from the seed extract of Psoralea corylfolia using 1 mM silver nitrate solution. The synthesized herbal mediated silver nanoparticles (HMSNP’s) then subjected to various characterization techniques such as XRD, SEM, EDX, TEM, DLS, UV and FT-IR respectively. In current study, the silver nanoparticles tested for in-vitro anti-diabetic activity and possible toxic effects in healthy female albino mice by following OECD guidelines-425. Herbal mediated silver nanoparticles were successfully obtained from bioreduction of silver nitrate using Psoralea corylifolia plant extract. Silver nanoparticles have been appropriately characterized and confirmed using different types of equipment viz., UV-vis spectroscopy, XRD, FTIR, DLS, SEM and EDX analysis. From the behavioral observations of the study, the female albino mice did not show sedation, respiratory arrest, and convulsions. Test compounds did not cause any mortality at the dose level tested (i.e., 2000 mg/kg body weight) doses till the end of 14 days of observation and were considered safe. It may be concluded that LD50 of the HMSNPs was 2000mg/kg body weight. Since LD50 of the HMSNPs was 2000mg/kg body weight, so the preferred dose range for HMSNPs falls between the levels of 200 and 400 mg/kg. Further In-vivo pharmacological models and biochemical investigations will clearly elucidate the mechanism of action and will be helpful in projecting the currently synthesized silver nanoparticles as a therapeutic target in treating chronic ailments.

Keywords: herbal mediated silver nanoparticles, HMSNPs, toxicity of silver nanoparticles, PTP1B in-vitro anti-diabetic assay female albino mice, 425 OECD guidelines

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Authors: Nadwah Onwi, Puspa Maniam, Azmawanie A. Aziz, Fairus Mukhtar, Nor Azrita Mohamed Zin, Nurul Haslina Mohd Zin, Nurul Fatehah Ismail, Mohamad Safwan Yusoff, Susilidianamanalu Abd Rahman, Siti Munirah Harris, Maryam Aizuddin

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Objective: Malaysia has a growing number of individuals with complex communication needs (CCN). The initiation of augmentative and alternative communication (AAC) intervention may facilitate individuals with CCN to understand and express themselves optimally and actively participate in activities in their daily life. AAC is defined as multimodal use of communication ability to allow individuals to use every mode possible to communicate with others using a set of symbols or systems that may include the symbols, aids, techniques, and strategies. It is consequently critical to evaluate the deficits to inform treatment for AAC intervention. However, no known measurement tools are available to evaluate the user with CCN available locally. Design: A systematic review (SR) is designed to analyze the psychometric properties of AAC assessment for adolescents with CCN published in peer-reviewed journals. Tools are rated by the methodological quality of studies and the psychometric measurement qualities of each tool. Method: A literature search identifying AAC assessment tools with psychometrically robust properties and conceptual framework was considered. Two independent reviewers screened the abstracts and full-text articles and review bibliographies for further references. Data were extracted using standardized forms and study risk of bias was assessed. Result: The review highlights the psychometric properties of AAC assessment tools that can be used by speech-language therapists applicable to be used in the Malaysian context. The work outlines how systematic review methods may be applied to the consideration of published material that provides valuable data to initiate the development of Malay Language AAC assessment tools. Conclusion: The synthesis of evidence has provided a framework for Malaysia Speech-Language therapists in making an informed decision for AAC intervention in our standard operating procedure in the Ministry of Health, Malaysia.

Keywords: augmentative and alternative communication, assessment, adolescents, complex communication needs

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Authors: Xi Wang, Yoshio Bando

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Lithium-ion batteries (LIBs) can deliver high levels of energy storage density and offer long operating lifetimes, but their power density is too low for many important applications. Therefore, we developed some new strategies and fabricated novel electrodes for fast Li transport and its facile synthesis including N-doped graphene-SnO2 sandwich papers, bicontinuous nanoporous Cu/Li4Ti5O12 electrode, and binder-free N-doped graphene papers. In addition, by using advanced in-TEM, STEM techniques and the theoretical simulations, we systematically studied and understood their storage mechanisms at the atomic scale, which shed a new light on the reasons of the ultrafast lithium storage property and high capacity for these advanced anodes. For example, by using advanced in-situ TEM, we directly investigated these processes using an individual CuO nanowire anode and constructed a LIB prototype within a TEM. Being promising candidates for anodes in lithium-ion batteries (LIBs), transition metal oxide anodes utilizing the so-called conversion mechanism principle typically suffer from the severe capacity fading during the 1st cycle of lithiation–delithiation. Also we report on the atomistic insights of the GN energy storage as revealed by in situ TEM. The lithiation process on edges and basal planes is directly visualized, the pyrrolic N "hole" defect and the perturbed solid-electrolyte-interface (SEI) configurations are observed, and charge transfer states for three N-existing forms are also investigated. In situ HRTEM experiments together with theoretical calculations provide a solid evidence that enlarged edge {0001} spacings and surface "hole" defects result in improved surface capacitive effects and thus high rate capability and the high capacity is owing to short-distance orderings at the edges during discharging and numerous surface defects; the phenomena cannot be understood previously by standard electron or X-ray diffraction analyses.

Keywords: in-situ TEM, STEM, advanced anode, lithium-ion batteries, storage mechanism

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Authors: Muhammad Ather Nadeem, Bilal Ahmad Khan, Tasawer Abbas

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Nanoherbicides utilize nanotechnology to enhance the delivery of biological or chemical herbicides using combinations of nanomaterials. The aim of this research was to examine the efficacy of chitosan nanoparticles containing MCPA herbicide as a potential eco-friendly alternative for weed control in wheat crops. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet absorbance were used to analyze the developed nanoparticles. The SEM analysis indicated that the average size of the particles was 35 nm, forming clusters with a porous structure. Both nanoparticles of fluroxyper + MCPA exhibited maximal absorption peaks at a wavelength of 320 nm. The compound fluroxyper +MCPA has a strong peak at a 2θ value of 30.55°, which correlates to the 78 plane of the anatase phase. The weeds, including Chenopodium album, Lathyrus aphaca, Angalis arvensis, and Melilotus indica, were sprayed with the nanoparticles while they were in the third or fourth leaf stage. There were seven distinct dosages used: doses (D0 (Check weeds), D1 (Recommended dose of traditional herbicide, D2 (Recommended dose of Nano-herbicide (NPs-H)), D3 (NPs-H with 05-fold lower dose), D4 ((NPs-H) with 10-fold lower dose), D5 (NPs-H with 15-fold lower dose), and D6 (NPs-H with 20-fold lower dose)). The chitosan-based nanoparticles of MCPA at the prescribed dosage of conventional herbicide resulted in complete death and visual damage, with a 100% fatality rate. The dosage that was 5-fold lower exhibited the lowest levels of plant height (3.95 cm), chlorophyll content (5.63%), dry biomass (0.10 g), and fresh biomass (0.33 g) in the broad-leaved weed of wheat. The herbicide nanoparticles, when used at a dosage 10-fold lower than that of conventional herbicides, had a comparable impact on the prescribed dosage. Nano-herbicides have the potential to improve the efficiency of standard herbicides by increasing stability and lowering toxicity.

Keywords: mortality, visual injury, chlorophyl contents, chitosan-based nanoparticles

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Authors: Christin Koch, Andreas Winkel, Martin Kahlmeyer, Stefan Böhm

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Due to environmental regulations on greenhouse gas emissions and the depletion of fossil fuels, there is an increasing interest in electric vehicles.To maximize their driving range, batteries with high storage capacities are needed. In most electric cars, rechargeable lithium-ion batteries are used because of their high energy density. However, it has to be taken into account that these batteries generate a large amount of heat during the charge and discharge processes. This leads to a decrease in a lifetime and damage to the battery cells when the temperature exceeds the defined operating range. To ensure an efficient performance of the battery cells, reliable thermal management is required. Currently, the cooling is achieved by heat sinks (e.g., cooling plates) bonded to the battery cells with a thermally conductive adhesive (TCA) that directs the heat away from the components. Especially when large amounts of heat have to be dissipated spontaneously due to peak loads, the principle of heat conduction is not sufficient, so attention must be paid to the mechanism of heat storage. An efficient method to store thermal energy is the use of phase change materials (PCM). Through an isothermal phase change, PCM can briefly absorb or release thermal energy at a constant temperature. If the phase change takes place in the transition from solid to liquid, heat is stored during melting and is released to the ambient during the freezing process upon cooling. The presented work displays the great potential of thermally conductive adhesives filled with microencapsulated PCM to limit peak temperatures in battery systems. The encapsulation of the PCM avoids the effects of aging (e.g., migration) and chemical reactions between the PCM and the adhesive matrix components. In this study, microencapsulation has been carried out by in situ polymerization. The microencapsulated PCM was characterized by FT-IR spectroscopy, and the thermal properties were measured by DSC and laser flash method. The mechanical properties, electrical and thermal conductivity, and adhesive toughness of the TCA/PCM composite were also investigated.

Keywords: phase change material, microencapsulation, adhesive bonding, thermal management

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Authors: Hami Ashraf, Mohammad Heydarnejad

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Introduction: The landscape of cancer treatment has been revolutionized by immunotherapy, offering novel therapeutic avenues for diverse cancer types. Animal models play a pivotal role in the development and elucidation of these therapeutic modalities. Nevertheless, the manifestation of Graft-versus-Host Disease (GVHD) in such models poses significant challenges, muddling the interpretation of experimental data within the ambit of cancer immunotherapy. This study is dedicated to scrutinizing the role of GVHD as a confounding factor in animal models used for cancer immunotherapy, alongside proposing viable strategies to mitigate this complication. Method: Employing a systematic review framework, this study undertakes a comprehensive literature survey including academic journals in PubMed, Embase, and Web of Science databases and conference proceedings to collate pertinent research that delves into the impact of GVHD on animal models in cancer immunotherapy. The acquired studies undergo rigorous analysis and synthesis, aiming to assess the influence of GVHD on experimental results while identifying strategies to alleviate its confounding effects. Results: Findings indicate that GVHD incidence significantly skews the reliability and applicability of experimental outcomes, occasionally leading to erroneous interpretations. The literature surveyed also sheds light on various methodologies under exploration to counteract the GVHD dilemma, thereby bolstering the experimental integrity in this domain. Conclusion: GVHD's presence critically affects both the interpretation and validity of experimental findings, underscoring the imperative for strategies to curtail its confounding impacts. Current research endeavors are oriented towards devising solutions to this issue, aiming to augment the dependability and pertinence of experimental results. It is incumbent upon researchers to diligently consider and adjust for GVHD's effects, thereby enhancing the translational potential of animal model findings to clinical applications and propelling progress in the arena of cancer immunotherapy.

Keywords: graft-versus-host disease, cancer immunotherapy, animal models, preclinical model

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Authors: Nidhi Gupta, Omita Nanda, Rakhi Grover, Kanchan Saxena

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Hybrid perovskite is new class of material which has gained much attention due to their different crystal structure and interesting optical and electrical properties. Easy fabrication, high absorption coefficient, and photoluminescence properties make them a strong candidate for various applications such as sensors, photovoltaics, photodetectors, etc. In perovskites, ions arrange themselves in a special type of crystal structure with chemical formula ABX3, where A is organic species like CH3NH3+, B is metal ion (e.g., Pb, Sn, etc.) and X is halide (Cl-, Br-, I-). In crystal structure, A is present at corner position, B at center of the crystal lattice and halide ions at the face centers. High stability and sensitivity of nanostructured perovskite make them suitable for chemical sensors. Researchers have studied sensing properties of perovskites for number of analytes such as 2,4,6-trinitrophenol, ethanol and other hazardous chemical compounds. Ammonia being highly toxic agent makes it a reason of concern for the environment. Thus the detection of ammonia is extremely important. Our present investigation deals with organic inorganic hybrid perovskite based ammonia sensor. Various methods like sol-gel, solid state synthesis, thermal vapor deposition etc can be used to synthesize Different hybrid perovskites. In the present work, a novel hybrid perovskite has been synthesized by a single step method. Ethylenediammnedihalide and lead halide were used as precursor. Formation of hybrid perovskite was confirmed by FT-IR and XRD. Morphological characterization of the synthesized material was performed using scanning electron microscopy (SEM). SEM analysis revealed the formation of one dimensional nanowire perovskite with mean diameter of 200 nm. Measurements for sensing properties of halide perovskite for ammonia vapor were carried out. Perovskite thin films showed a color change from yellow to orange on exposure of ammonia vapor. Electro-optical measurements show that sensor based on lead halide perovskite has high sensitivity towards ammonia with effective selectivity and reversibility. Sensor exhibited rapid response time of less than 20 seconds.

Keywords: hybrid perovskite, ammonia, sensor, nanostructure, thin film

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Authors: Mark Davies, Carolyn Wallace, Christina Lloydwin, Tom Powell

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Background: Frailty is increasingly recognized as a public health problem within an aging population. It is often characterized as an accumulation of clinical symptoms with progressive decline. We contend that dehydration is potentially the missing link driving the cycle of frailty; it contributes to malnutrition and cognitive decline and is a risk factor for other conditions. Frailty may also impact on fluid intake in cognitively intact older adults, indicating the cyclical nature of dehydration contributing to increasing frailty. Aim: To examine the relationships between fluid, hydration, and frailty in older adults in order to determine what works, for whom, how, why, and in what circumstances. Methods: A Realist Synthesis was first undertaken with n=50 studies, leading to the development of a Refined Programme Theory (RPT) articulating what hydration interventions work, for whom, to what degree, in what contexts, and how & why. Within the subsequent evaluation, the RPT was further confirmed/refuted/refined following semi-structured interviews with n=8 participants (healthcare professionals and patients). The RAMESES Quality Standards were followed throughout the study. Results: The Refined Programme Theory (RPT) highlighted three factors that result in optimized hydration for frail older people, i.e., Developing an Understanding Around Hydration, Empowering Participation, and System Reconfiguration. Our RPT indicates that hydration interventions work by developing an understanding of the importance of hydration, mitigating physical & cognitive barriers, increasing the agency of the patient, using a prompting process to reinforce drinking behavior, and routinizing hydration as a dimension of overall care. Conclusion: The study indicates that a greater understanding of the importance of hydration is required for all parties. Patients also require physical and psychological support if they are to be active agents in meeting their hydration needs. At a wider ‘system’ level, organizations must work in an integrated manner introducing processes that enable continuing professional development (CPD), encourage ongoing holistic assessment, and routinize hydration support.

Keywords: frailty, dehydration, older adults, realist review, realist evaluation

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Authors: Eman M. Sarhan, Doaa A. Ghareeb, Gabriella Ortore, Amr A. Amara, Mohamed M. El-Sayed

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Drug salting and nanoparticle-based drug delivery formulations are considered to be an effective means for rendering the hydrophobic drugs’ nano-scale dispersion in aqueous media, and thus circumventing the pitfalls of their poor solubility as well as enhancing their membrane permeability. The current study aims to increase the bioavailability of quaternary ammonium berberine through acid salting and biodegradable bovine serum albumin (BSA)-based nanoparticulate drug formulation. Berberine hydroxide (BBR-OH) that was chemically synthesized by alkalization of the commercially available berberine hydrochloride (BBR-HCl) was then acidified to get Di-berberine sulfate (BBR)₂SO₄. The purified crystals were spectrally characterized. The desolvation technique was optimized for the preparation of size-controlled BSA-BBR-HCl, BSA-BBR-OH, and BSA-(BBR)₂SO₄ nanoparticles. Particle size, zeta potential, drug release, encapsulation efficiency, Fourier transform infrared spectroscopy (FTIR), tandem MS-MS spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning and transmitting electron microscopic examination (SEM, TEM), in vitro bioactivity, and in silico drug-polymer interaction were determined. BSA (PDB ID; 4OR0) protonation state at different pH values was predicted using Amber12 molecular dynamic simulation. Then blind docking was performed using Lamarkian genetic algorithm (LGA) through AutoDock4.2 software. Results proved the purity and the size-controlled synthesis of berberine-BSA-nanoparticles. The possible binding poses, hydrophobic and hydrophilic interactions of berberine on BSA at different pH values were predicted. Antioxidant, anti-hemolytic, and cell differentiated ability of tested drugs and their nano-formulations were evaluated. Thus, drug salting and the potentially effective albumin berberine nanoparticle formulations can be successfully developed using a well-optimized desolvation technique and exhibiting better in vitro cellular bioavailability.

Keywords: berberine, BSA, BBR-OH, BBR-HCl, BSA-BBR-HCl, BSA-BBR-OH, (BBR)₂SO₄, BSA-(BBR)₂SO₄, FTIR, AutoDock4.2 Software, Lamarkian genetic algorithm, SEM, TEM, EDX

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Authors: Giorgi Gaganidze, Eter Kharaishvili

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The atypical crisis has created new challenges in the education system. Globally, including in Georgia, traditional methods of managing the education system have appeared particularly vulnerable. In addition, new opportunities for the introduction of innovative management of learning processes have emerged. The aim of the research is to identify the main challenges in the field of education management in the distance learning process in Georgia and to develop recommendations on the opportunities for the introduction of innovative management. The paper substantiates the relevance of the research, in particular, it notes that in Georgia, as in many countries, distance learning in higher education institutions became particularly crucial during the Covid-19 pandemic. What is more, theoretical and practical aspects of distance learning are less proven, and a number of problems have been identified in the field of education management in Georgia. The article justifies the need to study the challenges of distance learning for the formation of a sustainable education management system. Within the bibliographic research, there are grouped the opinions of researchers on the modern problems of distance learning and education management in the article. Based on scientific papers, the expectations formed about distance learning are studied, and the main focus is on the existing problems of education management during the atypical crisis. The article discusses the forms and opportunities of distance learning in different countries, evaluates different approaches and challenges to distance learning, and justifies the role of education management in effective distance learning. The paper uses various theoretical-methodological tools of research, including desk research on the research topic; Data selection-grouping, problem identification is carried out by analysis, synthesis, sampling, induction, and other methods;SWOT analysis is used to assess the strengths, weaknesses, opportunities, and threats of distance education and management; The level of student satisfaction with distance learning is determined through the Population-based / Census-based approach; The results of the research are processed by SPSS program. Quantitative research and semi-structured interviews with relevant focus groups were conducted to identify working directions for innovative management of distance learning and education. Research has shown that the demand for distance education is growing in Georgia, but the need to introduce innovative education management remains a particular challenge. Conclusions have been made on the introduction of innovative education management, and the relevant recommendations have been developed.

Keywords: distance learning, management challenges, education management, innovative management

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Authors: Mohamed M. Ibrahim, Gaber A. M. Mersal, Salih Al-Juaid, Samir A. El-Shazly

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A series of mixed ligand complexes, viz., [Cu(BPy)(Gly)X]Y {X = Cl (1), Y = 0; X = 0, Y = ClO4- (2); X = H2O, Y = NO3- (3); X = H2O, Y = CH3COO- (4); and [Cu(BPy)(Gly)-(H2O)]2(SO4) (5) have been synthesized. Their structures and properties were characterized by elemental analysis, thermal analaysis, IR, UV–vis, and ESR spectroscopy, as well as electrochemical measurements including cyclic voltammetry, electrical molar conductivity, and magnetic moment measurements. Complexes 1 and 2 formed slightly distorted square-pyramidal coordination geometries of CuN3OCl and CuN3O2, respectively in which the N,O-donor glycine and N,N-donor bipyridyl bind at the basal plane with chloride ion or water as the axial ligand. Complex 3 shows square planar CuN3O coordination geometry, which exhibits chemically significant hydrogen bonding interactions besides showing coordination polymer formation. The superoxide dismutase and catalase-like activities of all complexes were tested and were found to be promising candidates as durable electron-transfer catalyst being close to the efficiency of the mimicking enzymes displaying either catalase or tyrosinase activity to serve for complete reactive oxygen species (ROS) detoxification, both with respect to superoxide radicals and related peroxides. The DNA binding interaction with super coiled pGEM-T plasmid DNA was investigated by using spectral (absorption and emission) titration and electrochemical techniques. The results revealed that DNA intercalate with complexes 1 and 2 through the groove binding mode. The calculated intrinsic binding constant (Kb) of 1 and 2 were 4.71 and 2.429 × 105 M−1, respectively. Gel electrophoresis study reveals the fact that both complexes cleave super coiled pGEM-T plasmid DNA to nicked and linear forms in the absence of any additives. On the other hand, the interaction of both complexes with DNA, the quasi-reversible CuII/CuI redox couple slightly improves its reversibility with considerable decrease in current intensity. All the experimental results indicate that the bipyridyl mixed copper(II) complex (1) intercalate more effectively into the DNA base pairs.

Keywords: enzyme mimics, mixed ligand complexes, X-ray structures, antioxidant, DNA-binding, DNA cleavage

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Authors: Panagiotis Platanitis

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Purpose: This research paper seeks to review the empirical studies in the field of expatriate adjustment in East Asia in order to produce a thematic understanding of the current adjustment challenges, thus enabling practitioners to enrich their knowledge. Background: Learning to live, work, and function in a country and culture vastly different from that of one’s upbringing can pose some unique challenges in terms of adaptation and adjustment. This has led to a growing body of research about the adjustment of expatriate workers. Adjustment itself has been posited as a three-dimensional construct; work adjustment, interaction adjustment and general or cultural adjustment. Methodology: This qualitative systematic review has been conducted on all identified peer-reviewed empirical studies related to expatriate adjustment in East Asia. Five electronic databases (PsychInfo, Emerald, Scopus, EBSCO and JSTOR) were searched to December 2015. Out of 625 identified records, thorough evaluation for eligibility resulted in 15 relevant studies being subjected to data analysis. The quality of the identified research was assessed according to the Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields. The data were analysed by means of thematic synthesis for systematic reviews of qualitative research. Findings: Data analysis revealed five key themes. The themes developed were: (1) personality traits (2) types of adjustment, (3) language, (4) culture and (5) coping strategies. Types of adjustment included subthemes such as: Interaction, general, work, psychological, sociocultural and cross-cultural adjustment. Conclusion: The present review supported previous literature on the different themes of adjustment and it takes the focus from work and general adjustment to the psychological challenges and it introduces the psychological adjustment. It also gives a different perspective about the use of cross-cultural training and the coping strategies expatriates use when they are abroad. This review helps counselling psychologists to understand the importance of a multicultural approach when working with expatriates and also to be aware of what expatriates might face when working and living in East Asia.

Keywords: adjustment, counselling psychology, East Asia, expatriates

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Authors: Thalita Carvalho Martins de Castro, Núbia Bernardi

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Currently, studies evidence that our cities are portraits of social relations. In the midst of so many segregations, cultural buildings emerge as a place to assemble collective activities and expressions. Through theater, exhibitions, educational workshops, libraries, the architecture approaches human relations and seeks to propose meeting places. The purpose of this research is to deepen the discussions about the contributions of cultural buildings in the use of the spaces of the contemporary city, based on the data and measure collected in the master's research in progress. The graphic analysis of the insertion of contemporary cultural buildings seeks to highlight the social use of space. The urban insertions of contemporary cultural buildings in the city of São Paulo (Brazil) will be analyzed to understand the relations between the architectural form and its audience. The collected data describe a dynamic of flows and the permanence in the use of these spaces, indicating the contribution of the cultural buildings, associated with artistic production, in the dynamics of urban spaces and the social modifications of their milieu. Among the case studies, the research in development is based on the registration and graphic analysis of the Praça das Artes (2012) building located in the historical central region of the city, which after a long period of great degradation undergoes a current redevelopment. The choice of this building was based on four parameters, both on the architectural scale and on the urban scale: urban insertion, local impact, cultural production and a mix of uses. For the analysis will be applied two methodologies of graphic analysis, one with diagrams accompanied by texts and another with the active analysis for open space projects using complementary graphic methodologies, with maps, plants, info-graphics, perspectives, time-lapse videos and analytical tables. This research aims to reinforce the debates between the methodologies of form-use spaces and visual synthesis applied in cultural buildings, in order that new projects can structure public spaces as catalysts for social use, generating improvements in the daily life of its users and in the cities where they are inserted.

Keywords: cultural buildings, design methodologies, graphic analysis, public spaces

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Authors: K. Yang, Y. Wei, M. Zhang, S. Yong, R. Torah, J. Tudor, S. Beeby

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E-textiles are traditional textiles with integrated electronic functionality. It is an emerging innovation with numerous applications in fashion, wearable computing, health and safety monitoring, and the military and medical sectors. The piezoelectric effect is a widespread and versatile transduction mechanism used in sensor and actuator applications. Piezoelectric materials produce electric charge when stressed. Conversely, mechanical deformation occurs when an electric field is applied across the material. Lead Zirconate Titanate (PZT) is a widely used piezoceramic material which has been used to fabricate e-textiles through screen printing, electro spinning and hydrothermal synthesis. This paper explores an alternative fabrication process: Spray coating. Spray coating is a straightforward and cost effective fabrication method applicable on both flat and curved surfaces. It can also be applied selectively by spraying through a stencil which enables the required design to be realised on the substrate. This work developed a sprayable PZT based piezoelectric ink consisting of a binder (Fabink-Binder-01), PZT powder (80 % 2 µm and 20 % 0.8 µm) and acetone as a thinner. The optimised weight ratio of PZT/binder is 10:1. The components were mixed using a SpeedMixer DAC 150. The fabrication processes is as follows: 1) Screen print a UV-curable polyurethane interface layer on the textile to create a smooth textile surface. 2) Spray one layer of a conductive silver polymer ink through a pre-designed stencil and dry at 90 °C for 10 minutes to form the bottom electrode. 3) Spray three layers of the PZT ink through a pre-designed stencil and dry at 90 °C for 10 minutes for each layer to form a total thickness of ~250µm PZT layer. 4) Spray one layer of the silver ink through a pre-designed stencil on top of the PZT layer and dry at 90 °C for 10 minutes to form the top electrode. The domains of the PZT elements were aligned by polarising the material at an elevated temperature under a strong electric field. A d33 of 37 pC/N has been achieved after polarising at 90 °C for 6 minutes with an electric field of 3 MV/m. The application of the piezoelectric textile was demonstrated by fabricating a pressure sensor to switch an LED on/off. Other potential applications on e-textiles include motion sensing, energy harvesting, force sensing and a buzzer.

Keywords: piezoelectric, PZT, spray coating, pressure sensor, e-textile

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Authors: Brian Fleischli, Shani Robins

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In recent years, the implementation of wisdom skills, including emotional intelligence, mindfulness, empathy, compassion, gratitude, realism (Cognitive-Behavioral Therapy), and humility, within K-12 educational settings has demonstrated significant benefits in reducing stress, anxiety, anger, and conflict among students. This study summarizes the findings of research conducted over several years, showcasing the positive outcomes associated with teaching these skills to elementary and high school students. Additionally, this overview includes an updated synthesis of current literature concerning the application and effectiveness of training these skill sets in K-12 schools. The research outcomes highlight substantial improvements in student well-being and behavior. Demonstrated with treatment group students exhibiting notable reductions in anger, anxiety, depression, and disruptive behaviors compared to control groups. For instance, fourth-grade students showed enhanced empathy, responsibility, and attention, particularly benefiting those with lower initial scores on these measures. Specific interaction effects suggest that older students and males particularly benefit from these interventions, showcasing the nuanced impact of wisdom skill training across different demographics. Furthermore, this presentation emphasizes the critical role of Social and Emotional Learning (SEL) programs in addressing the multifaceted challenges faced by children and adolescents, including mental health issues, academic performance, and social behaviors. The integration of wisdom skills into school curricula not only fosters individual growth and emotional regulation but also enhances overall school climate and academic achievement. In conclusion, the findings contribute to the growing body of empirical evidence supporting the efficacy of teaching wisdom skills in educational settings. The success of these interventions underscores the potential for widespread implementation of evidence-based programs to promote emotional well-being and academic success among students nationwide.

Keywords: wisdom skills, CBT, cognitive behavioral training, mindfulness, empathy, anxiety

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Authors: Cristina Munoz-Shuguli, Francisco Rodriguez, Julio Bruna, M. Jose Galotto, Abel Guarda

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The microbial contamination in fruits due to the presence of fungal is the most important cause of their deterioration and loss. The development of active food packaging materials with antifungal properties has been proposed as an innovative strategy in order to prevent this problem. In this way, natural compounds as the essential oils or their derivatives, also called volatile compounds (VC), can be incorporated in the food packaging materials to control the fungal growth during fruit packaging. However, if the VC is incorporated directly in the packaging material, it is released very fast due to VC high volatility. For this reason, the formation of inclusion complexes through the encapsulation of VC into beta-cyclodextrin (β-CD) and their incorporation in package materials is an alternative to maintain an antifungal atmosphere around the packaged fruits for longer times. In this context, the aim of this work was to develop inclusion complexes based in β-CD and VC (β-CD:VC) for further application in the antifungal food packaging materials development. β-CD:VC inclusion complexes were obtained with two different molar ratios 2:1 and 1:1, through co-precipitation method. The entrapment efficiency of β-CD:VC as well the release of antifungal compound from inclusion complexes exposed to different relative humidity (25, 50, and 97 %) to headspace were determined by gaseous chromatography (GC). Also, thermal and antimicrobial properties of β-CD:VC were determined through thermogravimetric analysis (TGA) and antifungal assays against Botrytis cinerea, respectively. GC results showed that β-CD:VC 2:1 had a higher entrapment efficiency than β-CD:VC 1:1, with values of 75.5 ± 3.71 % and 59.6 ± 1.51 %, respectively. It was probably because during the synthesis of β-CD:VC 1:1, there was less molecular space to the movement of VC molecules. Furthermore, the release of VC from β-CD:VC was directly related with the relative humidity. High amount of VC was released when the inclusion complexes were exposed to high humidity, possibly due to the interactions between the water molecules and the β-CD hydrophilic wall. On the other hand, a better thermal stability of VC in inclusion complexes allowed to verify its effective encapsulation into β-CD. Finally, antimicrobial assays showed that the inclusion complexes had a high antifungal activity at very low concentrations. Therefore, the results obtained in this work allow suggesting the β-CD:VC inclusion complexes as potential candidates to the development of fruit antifungal packaging materials, which activity is relative humidity dependent.

Keywords: Botrytis cinerea, fruit packaging, headspace release, volatile compounds

Procedia PDF Downloads 122

Authors: Amir Shafiee Kisomi, Mehrdad Mofidi

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Nowadays, fuel cells as a promising alternative for power source have been widely studied owing to their security, high energy density, low operation temperatures, renewable capability and low environmental pollutant emission. The nanoparticles of core-shell type could be widely described in a combination of a shell (outer layer material) and a core (inner material), and their characteristics are greatly conditional on dimensions and composition of the core and shell. In addition, the change in the constituting materials or the ratio of core to the shell can create their special noble characteristics. In this study, a fast technique for the fabrication of a Pd-Co/G/GCE modified electrode is offered. Thermal decomposition reaction of cobalt (II) formate salt over the surface of graphene/glassy carbon electrode (G/GCE) is utilized for the synthesis of Co nanoparticles. The nanoparticles of Pd-Co decorated on the graphene are created based on the following method: (1) Thermal decomposition reaction of cobalt (II) formate salt and (2) the galvanic replacement process Co by Pd2+. The physical and electrochemical performances of the as-prepared Pd-Co/G electrocatalyst are studied by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), Cyclic Voltammetry (CV), and Chronoamperometry (CHA). Galvanic replacement method is utilized as a facile and spontaneous approach for growth of Pd nanostructures. The Pd-Co/G is used as an anode catalyst for ethanol oxidation in alkaline media. The Pd-Co/G not only delivered much higher current density (262.3 mAcm-2) compared to the Pd/C (32.1 mAcm-2) catalyst, but also demonstrated a negative shift of the onset oxidation potential (-0.480 vs -0.460 mV) in the forward sweep. Moreover, the novel Pd-Co/G electrocatalyst represents large electrochemically active surface area (ECSA), lower apparent activation energy (Ea), higher levels of durability and poisoning tolerance compared to the Pd/C catalyst. The paper demonstrates that the catalytic activity and stability of Pd-Co/G electrocatalyst are higher than those of the Pd/C electrocatalyst toward ethanol oxidation in alkaline media.

Keywords: thermal decomposition, nanostructures, galvanic replacement, electrocatalyst, ethanol oxidation, alkaline media

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Authors: Zahidul Islam

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This study investigates the effectiveness of resourcing in post-disaster housing reconstruction with reference to Cyclones Sidr and Aila in Bangladesh. Through evaluating three key theories- Build Back Better approach, Balance Scorecard approach and Dynamic Competency theories, the synthesis of literature, and empirical fieldwork, this research develops a dynamic theoretical framework that moves the trajectory of post-disaster housing reconstruction towards the reconstruction of more resilient houses. The ultimate goal of any post-disaster housing reconstruction project is to provide quality houses and to achieve high levels of satisfaction for beneficiaries. However, post-disaster reconstruction projects often fail in their stated objectives; only 10-20% housing needs are met, with most houses constructed on a temporary rather than permanent basis. A number of scholars have argued that access to resources can significantly increase the capacity and capability of disaster victims to rebuild their lives, including the construction of new homes. This study draws on structured interviews of 285 villagers affected by cyclones to investigate the effectiveness of resourcing in rebuilding houses after Cyclone Sidr in 2007 and Cyclone Aila in 2009. Furthermore, semi-structured interviews were conducted with 20 key stakeholders in UNDP, Oxfam, government officials, and national and international NGOs. The results of this study show that recovery rate of cyclone resilient houses that can withstand cyclone is very low and majority of the population are still vulnerable. Furthermore, hierarchical regression of survey data and thematic analyses of qualitative data indicate that access to resources, level of education, quality of building materials and income generating activities of the respondents are critical for effective post-disaster recovery. Conversely, resource availability, lack of coordination among participant organisations, corruption and lack of access to appropriate land constituted significant obstacles to livelihood recovery. Finally, this study makes significant theoretical contributions to theories of post-disaster recovery by introducing new variables and measures for evaluating the quality and effectiveness of post-disaster housing.

Keywords: disaster, resourcing, housing, resilience

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Authors: Liqin Zhi, Lin Xu, Wenxia Wei, Yaqi Cai

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Recently, replacing some of the methyl groups in polydimethylsiloxanes with other functional groups has been extensively explored to obtain modified polymethylsiloxanes with special properties that enable new industrial applications. Fluorinated polysiloxanes, one type of these modified polysiloxanes, are based on a siloxane backbone with fluorinated groups attached to the side chains of polysiloxanes. As a commercially significant material, poly[methyl(trifluoropropyl)siloxane] (PMTFPS) has sufficient fluorine content to be useful as a fuel-and oil-resistant elastomer, which combines both the chemical and solvent resistance of fluorocarbons and the wide temperature range applicability of organosilicones. PMTFPS products can be used in many applications in which resistance to fuel, oils and hydrocarbon solvents is required, including use as lubricants in bearings, sealants, and elastomers for aerospace and automotive fuel systems. Fluorinated methylsiloxanes, a type of modified methylsiloxane, include tris(trifluoropropyl)trimethylcyclotrisiloxane (D3F) and tetrakis(trifluoropropyl)tetramethylcyclotetrasiloxane (D4F), both of which contain trifluoropropyl groups in the side chains of cyclic methylsiloxanes. D3F, as an important monomer in the manufacture of PMTFPS, is often present as an impurity in PMTFPS. In addition, the synthesis of PMTFPS from D3F could form other fluorinated methylsiloxanes with low molecular weights (such as D4F). The yearly demand and production volumes of D3F increased rapidly all over world. Fluorinated methylsiloxanes might be released into the environment via different pathways during the production and application of PMTFPS. However, there is a lack of data concerning the emission, environmental occurrence and potential environmental impacts of fluorinated methylsiloxanes. Here, we report fluorinated methylsiloxanes (D3F and D4F) in surface water and sediment samples collected near a fluorinated methylsiloxane manufacturing plant in Weihai, China. The concentrations of D3F and D4F in surface water ranged from 3.29 to 291 ng/L and from 7.02 to 168 ng/L, respectively. The concentrations of D3F and D4F in sediment ranged from 11.8 to 5478 ng/g and from 17.2 to 6277 ng/g, respectively. In simulation experiment, the half-lives of D3F and D4F at different pH values (5.2, 6.4, 7.2, 8.3 and 9.2) varied from 80.6 to 154 h and from 267 to 533 h respectively. CF₃(CH₂)₂MeSi(OH)₂ was identified as one of the main hydrolysis products of fluorinated methylsiloxanes. It was also detected in the river samples at concentrations of 72.1-182.9 ng/L. In addition, the slow rearrangement of D3F (spiked concentration = 500 ng/L) to D4F (concentration = 11.0-22.7 ng/L) was also found during 336h hydrolysis experiment.

Keywords: fluorinated methylsiloxanes, environmental matrices, hydrolysis, sediment

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Authors: S. Curteanu, F. Leon, M. Gavrilescu, S. A. Floria

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Optimization algorithms inspired from human behavior were applied in this approach, associated with neural networks models. The algorithms belong to human behaviors of learning and cooperation and human competitive behavior classes. For the first class, the main strategies include: random learning, individual learning, and social learning, and the selected algorithms are: simplified human learning optimization (SHLO), social learning optimization (SLO), and teaching-learning based optimization (TLBO). For the second class, the concept of learning is associated with competitiveness, and the selected algorithms are sports-inspired algorithms (with Football Game Algorithm, FGA and Volleyball Premier League, VPL) and Imperialist Competitive Algorithm (ICA). A real process, the synthesis of polyacrylamide-based multicomponent hydrogels, where some parameters are difficult to obtain experimentally, is considered as a case study. Reaction yield and swelling degree are predicted as a function of reaction conditions (acrylamide concentration, initiator concentration, crosslinking agent concentration, temperature, reaction time, and amount of inclusion polymer, which could be starch, poly(vinyl alcohol) or gelatin). The experimental results contain 175 data. Artificial neural networks are obtained in optimal form with biologically inspired algorithm; the optimization being perform at two level: structural and parametric. Feedforward neural networks with one or two hidden layers and no more than 25 neurons in intermediate layers were obtained with values of correlation coefficient in the validation phase over 0.90. The best results were obtained with TLBO algorithm, correlation coefficient being 0.94 for an MLP(6:9:20:2) – a feedforward neural network with two hidden layers and 9 and 20, respectively, intermediate neurons. Good results obtained prove the efficiency of the optimization algorithms. More than the good results, what is important in this approach is the simulation methodology, including neural networks and optimization biologically inspired algorithms, which provide satisfactory results. In addition, the methodology developed in this approach is general and has flexibility so that it can be easily adapted to other processes in association with different types of models.

Keywords: artificial neural networks, human behaviors of learning and cooperation, human competitive behavior, optimization algorithms

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Authors: Eteri Kharaishvili

Abstract:

Introduction. The paper analyzes the main indicators of export and import of Georgian agri-food products; identifies positive and negative trends under the pandemic; based on the revealed problemssubstantiates the need formodernization ofin agri-food sector. It is argued that low production and productivity rates of food products negatively impact achieving the optimal export-to-import ratio; therefore, it leads toincreaseddependence on other countries andreduces the level of food security. Research objectives. The objective of the research is to identify the key challenges based on the analysis of export-import indicators of Georgian food products during the pandemic period and develop recommendations on the possibilities of post-pandemic perspectives. Research methods. Various theoretical and methodological research tools are used in the paper; in particular, a desk research is carried out on the research topic; endogenous and exogenous variables affecting export and import are determined through factor analysis; SWOT and PESTEL analysis are used to identify development opportunities; selection and groupingof data, identification of similarities and differences is carried outby using analysis, synthesis, sampling, induction and other methods; a qualitative study is conducted based on a survey of agri-food experts and exporters for clarifying the factors that impede export-import flows. Contributions. The factors that impede the export of Georgian agri-food products in the short run under COVID-19 pandemic are identified. These are: reduced income of farmers, delays in the supply of raw materials and supplies to the agri-food sectorfrom the neighboring industries, as well as in harvesting, processing, marketing, transportation, and other sectors; increased indirect costs, etc. The factors that impede the export in the long run areas follows loss of public confidence in the industry, risk of losing positions in traditional markets, etc. Conclusions are made on the problems in the field of export and import of Georgian agri-food products in terms of the pandemic; development opportunities are evaluated based on the analysis of the agri-food sector potential. Recommendations on the development opportunities for export and import of Georgian agri-food products in the post-pandemic period are proposed.

Keywords: agri-food products, export, and import, pandemic period, hindering factor, development potential

Procedia PDF Downloads 143