What are tutors' perceptions of an online tutoring project-Digital Learning Companion-During the COVID-19 pandemic? A case study in Taiwan.

The COVID-19 outbreak has had serious impact on remote education and service-learning implementation in Taiwan. To alleviate these impacts, the Digital Learning Companion, an online tutoring project, was proposed to bridge the digital divide and learning gap among remote children, while offering university students an online service-learning environment. This project recruited international students as tutors for local children. To explore tutors' perceptions of this project during the COVID-19 pandemic, qualitative research, particularly a case study, was conducted. Adopting purposive sampling, 15 participants were chosen for interviews at the end of the project, and 10 reflective videos were used to reveal further information to supplement the interview results. Content analysis was employed to analyse the data. The findings implied that using JoinNet and tutoring journals significantly facilitated the tutoring process, which led to tutors' remarkable development in skills, social relationships, multicultural experience, altruism, social responsibility, self-efficacy, and affective values. However, they encountered some challenges, such as technical problems, communication barrier, lack of tutee information, and short tutoring duration. The solutions to these challenges and insightful suggestions for the project development are pointed out. The results of this study contribute to tutors' cognitive, social, and motivational development, and support the online service-learning-integrated curriculum, which can become a reference for further studies regarding online service-learning implementation to bridge the research gap.

Knowledge, attitudes, and practices of university students regarding COVID-19: a cross-sectional study in Vietnam.

OBJECTIVE: This cross-sectional study investigated the knowledge, attitudes, and practices (KAP) of Vietnamese university students regarding COVID-19. METHODS: A validated questionnaire (Cronbach's alpha = 0.71) was used to survey 1,025 students. A convenience sampling method was used for recruiting students from April to May 2022. The Wilcoxon rank-sum test and the Kruskal-Wallis rank-sum test/Dunn test for multiple comparisons were employed to compare students' KAP scores between two groups and among three groups or more, respectively. Factors associated with students' COVID-19 KAP scores were determined via univariate and multivariate linear regression models. Variables in the multivariate linear regression models were chosen using the Bayesian Model Averaging method in R software version 4.2.0. RESULTS: A majority of students had good knowledge (75.61%), positive attitudes (98.24%), and good practices toward COVID-19 (94.93%). Regarding the COVID-19 knowledge, the proportions of students who knew that mosquito bites and exposure to/eating wild animals would not lead to COVID-19 infection were not high (47.22 and 34.34%, respectively). More importantly, 70.34% of students thought that vitamins and minerals could help prevent or cure COVID-19. Antibiotics were the first choice for COVID-19 treatment of 438 students (42.73%). Nearly half of students (48.0%) bought antibiotics to keep at home in case of COVID-19 infection. The average KAP scores of medical students (19.97 ± 3.99, 45.10 ± 3.94, 9.72 ± 1.78) and females (18.67 ± 4.44, 44.79 ± 3.79, 9.36 ± 1.84) were significantly higher than those of non-medical students (16.48 ± 4.37, 43.33 ± 4.03, 8.68 ± 1.87) and males (17.01 ± 4.55, 42.79 ± 4.39, 8.77 ± 1.97), respectively (p < 0.001). Older students were more likely to have good knowledge and practices than the younger ones (p < 0.001). In addition, students using websites of the World Health Organization/the Ministry of Health and scientific articles to seek COVID-19 information were significantly associated with higher KAP scores when compared with those not using these sources (p < 0.001, p < 0.001, and p = 0.00139, respectively). CONCLUSION: Students' KAP scores significantly varied by age, sex, major, and sources of COVID-19 information. Although many students had sufficient knowledge, positive attitudes, and good preventive practices toward COVID-19, additional education and training strategies are paramount, especially for non-medical students and males.

Facile synthesis of superparamagnetic thiamine/Fe3O4 with enhanced adsorptivity toward divalent copper ions.

The development of environmentally friendly adsorbents has been extensively carried out to overcome the detrimental effects of heavy metal accumulation, which has persistently become a global ecological problem. In pursuit of generating eco-friendly adsorbents, a green method for synthesizing thiamine functionalized-Fe3O4 (FT) was developed in this study. A one-step chemical oxidation and functionalization technique was used to prepare FT using the ammonia-containing solvent. A molar ratio of ammonia:Fe:thiamine of 15:1:1 was shown to produce FT15 with high yield, adsorptivity, and purity. XRD, XPS, FTIR, SEM, and SQUID characterization of FT15 revealed the formation of superparamagnetic thiamine functionalized Fe3O4 in their particles. This superparamagneticity facilitates the easy recovery of FT15 particles from the waste-containing solution by using an external magnetic force. The batch adsorption of Cu(II) onto FT15 showed the best fit with the Sips adsorption isotherm model with a maximum adsorption capacity of 426.076 mg g-1, which is 5.69-fold higher capacity than the control unmodified Fe3O4 (F15). After five adsorption-desorption cycles, the FT15 can maintain up to 1.95-fold higher capacity than the freshly synthesized F15. Observation on the physicochemical properties of the post-adsorption materials showed the contribution of an amine group, pyrimidine ring, and the thiazolium group of thiamine in boosting its adsorption capacity. This study provides important findings to advance the adsorptivity of magnetic adsorbents with promising recoverability from aqueous solution by employing naturally available and environmentally friendly compounds such as thiamine.

TiO2/guar gum hydrogel composite for adsorption and photodegradation of methylene blue.

The development of porous adsorbent materials from renewable resources for water and wastewater treatment has received considerable interest from academia and industry. This work aims to synthesize composite hydrogel from the combination of guar gum (a neutral galactomannan polysaccharide) and TiO2. The TiO2-embedded guar gum hydrogel (TiO2@GGH) was utilized to remove methylene blue through adsorption and photodegradation. The presence of TiO2 particles in the hydrogel matrix (TiO2@GGH) was confirmed by scanning electron microscopy-energy dispersive X-ray and X-ray photoelectron spectroscopy analysis. The mercury intrusion and N2 sorption isotherm indicate the macroporous structure of the TiO2@GGH composite, showing the presence of pore sizes ~420 µm. The dye removal efficiency of the GGH and TiO2@GGH was evaluated in batch mode at ambient temperature under varying pH. The effect of UV radiation on the dye removal efficiency was also assessed. The results demonstrated that the highest dye removal was recorded at pH 10, with the equilibrium condition achieved within 5 h. UV radiation was shown to enhance dye removal. The maximum adsorption capacity of TiO2@GGH is 198.61 mg g-1, while GGH sorbent is 188.53 mg g-1. The results imply that UV radiation gives rise to the photodegradation effect.

Evaluation of silicone hydrogel contact lenses based on poly(dimethylsiloxane) dialkanol and hydrophilic polymers.

Silicone hydrogel lenses were prepared by copolymerizing PDMS-PEGMA macromer (PGP) with various combinations of DMA, NVP, and PEGMA through UV initiated polymerization process. The resultant PGP macromer were characterized by gel permeation chromatography (GPC), and scanning electron microscope (SEM-EDS). Characterization of all the resultant co-polymers included Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), equilibrium water content (EWC), oxygen permeability (Dk), optical transparency, contact angle, mechanical properties, zeta potential, protein deposition, and cytotoxicity. The results show that higher content of hydrophilic polymers increased water uptake ability as well as improved hydrophilicity and modulus of silicone hydrogel lenses; however, oxygen permeability decreased with the decrease of PDMS content (145 barrers of PGP to 37 barrers of DP0). In addition, these silicone hydrogel lenses exhibited relatively optical transparency, anti-protein deposition, and non-cytotoxic according to an in vitro L929 fibroblast assay. Therefore, these silicone hydrogel polymers would be applicable for making contact lens.

One-step synthesis of nitrogen-grafted copper-gallic acid for enhanced methylene blue removal.

Nitrogen-grafting through the addition of glycine (Gly) was performed on a metal- phenolic network (MPN) of copper (Cu2+) and gallic acid (GA) to increase its adsorption capacity. Herein, we reported a one-step synthesis method of MPN, which was developed according to the metal-ligand complexation principle. The nitrogen grafted CuGA (Ng-CuGA) MPN was obtained by reacting Cu2+, GA, and Gly in an aqueous solution at a molar ratio of 1:1:1 and a pH of 8. Several physicochemical measurements, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), N2 sorption, X-ray diffraction (XRD), and thermal gravimetry analysis (TGA), were done on Ng-CuGA to elucidate its characteristics. The analysis revealed that the Ng-CuGA has non-uniform spherical shaped morphology with a pore volume of 0.56 cc/g, a pore size of 23.25 nm, and thermal stability up to 205 °C. The applicational potential of the Ng-CuGA was determined based on its adsorption capacity against methylene blue (MB). The Ng-CuGA was able to adsorb 190.81 mg MB per g adsorbent at a pH of 6 and temperature of 30 °C, which is 1.53 times higher than the non-grafted CuGA. Detailed assessment of Ng-CuGA adsorption properties revealed their pH- and temperature-dependent nature. The adsorption capacity and affinity were found to decrease at a higher temperature, demonstrating the exothermic adsorption behavior.

Aqueous synthesis of highly adsorptive copper-gallic acid metal-organic framework.

A greener route to synthesize mesoporous copper-gallic acid metal-organic framework (CuGA MOF) than the conventional method using harmful DMF solvent was proposed in this study. Various synthesis attempts were conducted by modifying the synthesis conditions to produce CuGA MOF with comparable physical properties to a reference material (DMF-synthesized CuGA NMOF). The independent variables investigated include the molar ratio of NaOH to GA (1.1 to 4.4) and the synthesis temperature (30, 60, 90 °C). It was found that proper NaOH addition was crucial for suppressing the generation of copper oxide while maximizing the formation of CuGA MOF. On the other hand, the reaction temperature mainly affected the stability and adsorption potential of CuGA MOF. Reacting Cu, GA, and NaOH at a molar ratio of 1:1:2.2 and a temperature of 90 °C, produced mesoporous MOF (CuGA 90-2.2) with a surface area of 198.22 m2/g, a pore diameter of 8.6 nm, and a thermal stability of 219 °C. This MOF exhibited an excellent adsorption capacity for the removal of methylene blue (124.64 mg/g) and congo red (344.54 mg/g). The potential usage of CuGA 90-2.2 as a reusable adsorbent was demonstrated by its high adsorption efficiency (> 90%) after 5 adsorption-desorption cycles.

Increased Access to and Use of Endovascular Therapy Following Implementation of a 2-Tiered Regional Stroke System.

Background and Purpose- We quantified population access to endovascular-capable centers, timing, and rates of thrombectomy in Los Angeles County before and after implementing 2-tiered routing in a regional stroke system of care. Methods- In 2018, the Los Angeles County Emergency Medical Services Agency implemented transport of patients with suspected large vessel occlusions identified by Los Angeles Motor Scale ≥4 directly to designated endovascular-capable centers. We calculated population access to a designated endovascular-capable center within 30 minutes comparing 2016, before 2-tiered system planning began, to 2018 after implementation. We analyzed data from stroke centers in the region from 1 year before and after implementation to delineate changes in rates and speed of administration of tPA (tissue-type plasminogen activator) and thrombectomy and frequency of interfacility transfer. Results- With implementation of the 2-tier system, certified endovascular-capable hospitals increased from 4 to 19 centers, and within 30-minute access to endovascular care for the public in Los Angeles County, from 40% in 2016 to 93% in 2018. Comparing Emergency Medical Services-transported stroke patients in the first post-implementation year (N=3303) with those transported in the last pre-implementation year (N=3008), age, sex, and presenting deficit severity were similar. The frequency of thrombolytic therapy increased from 23.8% to 26.9% (odds ratio, 1.2 [95% CI, 1.05-1.3]; P=0.006), and median first medical contact by paramedic-to-needle time decreased by 3 minutes ([95% CI, 0-5] P=0.03). The frequency of thrombectomy increased from 6.8% to 15.1% (odds ratio, 2.4 [95% CI, 2.0-2.9]; P<0.0001), although first medical contact-to-puncture time did not change significantly, median decrease of 8 minutes ([95% CI, -4 to 20] P=0.2). The frequency of interfacility transfers declined from 3.2% to 1.0% (odds ratio, 0.3 [95% CI, 0.2-0.5]; P<0.0001). Conclusions- After implementation of 2-tiered stroke routing in the most populous US county, thrombectomy access increased to 93% of the population, and the frequency of thrombectomy more than doubled, whereas interfacility transfers declined.

Knowledge, attitudes, and practices among university students in relation to dengue fever: A multi-center study across Vietnamese regions.

OBJECTIVE: Dengue fever (DF) is a serious illness worldwide that can spread rapidly and become a dangerous epidemic. Vietnam is an endemic country affected by the health and economic burden of dengue. This study was conducted to assess the knowledge, attitudes, and practices related to DF among university students across Vietnam. METHODS: A student-based cross-sectional study was performed with a structured questionnaire in Vietnam between July and September 2018. A Chi-square test and Fisher's exact test were used to compare different issues between two student groups, including medical and non-medical student, and P-values of <0.05 were considered significant. RESULTS: A total of 1,542 students from universities in Vietnam responded to the survey, which was reflective of 315 medical students learning in public schools, 689 medical students learning in private schools, and 538 non-medical students. The majority of participants had good knowledge on the transmission of DF, good attitudes toward DF, and good practices to prevent the disease. Medical students had better knowledge of the signs and symptoms than non-medical students. However, both student groups' knowledge of signs and symptoms was low. CONCLUSIONS: Quality of education is a key determinant of the knowledge of the disease, as well as of attitudes and practices. This study supported the government's implementation of intervention projects and DF prevention campaigns and its positive participation in the community.

DoE-based development, physicochemical characterization, and pharmacological evaluation of a topical hydrogel containing betamethasone dipropionate microemulsion.

This study was performed to achieve two primary goals: First, a microemulsion containing betamethasone dipropionate was optimized using the quality by design approach. Second, a hydrogel-containing microemulsion was developed using cellulose derivatives, and its anti-inflammatory and skin irritation effects were evaluated. Face-centered central composite design was used to investigate the impacts of two independent variables (oleic acid and ratio of surfactant to cosolvent, S/CoS) on three dependent variables (skin deposition, flux of BMD, and microemulsion droplet size). The microemulsion including oleic acid at a low level (coded with -1) and S/CoS at a high level (coded with +1) was considered optimal since it was the most effective in terms of skin deposition and flux of BMD. Different cellulose derivatives (HPMC E6, HEC, NaCMC, and CMC) were screened to prepare a hydrogel-containing microemulsion based on four properties: flux and skin deposition of BMD, hydration of stratum corneum, and rheological properties of hydrogel-containing microemulsion (ME-hydrogel). The anti-inflammatory effect and flux of BMD from optimal ME-hydrogel with carboxymethyl cellulose as the hydrogel-forming agent were then compared to those of the hydrogel-containing solid lipid nanoparticles (SLN-hydrogel) and nanostructure lipid carriers (NLC-hydrogel). The percentage of edema inhibition declined proportionally with flux of BMD in the following order: ME-hydrogel (44.56 ±â€¯8.08%) > NLC-hydrogel (35.93 ±â€¯7.22%) > SLN-hydrogel (25.68 ±â€¯9.05%).

Solution Equilibrium Study of Divalent Metal Ions with Phenylpropanoid Derivatives and Acetylcysteine Ligands.

Solution equilibrium of divalent metal ions (M=Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) with caffeic acid (ligand C) or dihydrocaffeic acid (ligand D) in binary system, and with acetylcysteine (ligand N) in ternary system were investigated at condition similar to human physiological temperature of 310.15 K and ionic strength of 0.15 mol·dm-3 NaCl. Potentiometry technique was used for the determination of formation constant (log ß) assisted by spectrophotometry technique. The results indicated the formation of [ML], [MLH], [ML2], [ML2H] in binary species and [MLN], [MNLH], [MNLH2] in ternary species, where L represents ligands C or D. It was found that ligand D formed more stable complexes than that of ligand C, which were affected by the presence of double bond in the carboxylate moiety of ligand C. The speciation diagrams were simulated by HySS and discussed briefly, additionally the tendency of ternary complexes was evaluated from parameters Δ log KM and log X.

Transesterification of activated sludge in subcritical solvent mixture.

Most previous studies reported in literature on biodiesel production from sludge were performed by acid catalyzed transesterification that required long reaction time (about 24h) and high methanol loading. The objective of this study was to investigate the in situ transesterification of sludge in subcritical mixture of methanol and acetic acid. At 250°C and a solvent (85% methanol and 15% acetic acid) to sludge ratio of 5 (mLg(-1)), a FAME yield of 30.11% can be achieved in 30min, compared to the yield of 35% obtained by the acid-catalyzed (4% H2SO4) transesterification which required 24h at 55°C and a methanol to sludge ratio of 25 (mLg(-1)). The method developed in this study avoided using mineral acid, significantly reduced reaction time and methanol loading to achieve comparable FAME yield.

Effect of extraction solvent on total phenol content, total flavonoid content, and antioxidant activity of Limnophila aromatica.

Limnophila aromatica is commonly used as a spice and a medicinal herb in Southeast Asia. In this study, water and various concentrations (50%, 75%, and 100%) of methanol, ethanol, and acetone in water were used as solvent in the extraction of L. aromatica. The antioxidant activity, total phenolic content, and total flavonoid content of the freeze-dried L. aromatica extracts were investigated using various in vitro assays. The extract obtained by 100% ethanol showed the highest total antioxidant activity, reducing power and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The same extract also exhibited the highest phenolic content (40.5 mg gallic acid equivalent/g of defatted L. aromatica) and the highest flavonoid content (31.11 mg quercetin equivalent/g of defatted L. aromatica). The highest extraction yield was obtained by using 50% aqueous acetone. These results indicate that L. aromatica can be used in dietary applications with a potential to reduce oxidative stress.

Impact of pretreatments on morphology and enzymatic saccharification of shedding bark of Melaleuca leucadendron.

The effects of subcritical water (SCW) and dilute acid pretreatments on the shedding bark of Melaleuca leucadendron (paper bark tree, PBT) biomass morphology, crystallinity index (CrI) and enzymatic saccharification were studied. The morphology of PBT bark was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. SCW pretreatment mainly extracted amorphous parts of the biomass hence its CrI increased, partial decrystallization of cellulose and exposing of intact nanofibers of cellulose were observed for SCW pretreatment at 180°C. On the other hand, dilute acid pretreatment at 160°C exhibited a large decrease in CrI, an increase in surface area, a decrease in lignin content and decrystallization of cellulose as well as the peel-off and degradation of some nanofiber bundles. Dilute acid and SCW pretreatments of PBT biomass resulted in about 4.5 fold enhancement in glucose release relative to the untreated one.

Bioethanol production from pretreated Melaleuca leucadendron shedding bark--simultaneous saccharification and fermentation at high solid loading.

Bioethanol production from the shedding bark of Melaleuca leucadendron (Paper-bark Tree, PBT) was studied using subcritical water (SCW) pretreatment at various severities (So). High ethanol production was attained by implementing a factorial design on three parameters (So, solid loading and enzyme loading) in simultaneous saccharification and fermentation (SSF) mode. Ethanol concentration of 63.2 g L(-1) corresponding to ethanol yield of 80.9% were achieved from pretreated biomass (So=2.37) at 0.25 g mL(-1) solid and 16 FPU g(-1) glucan enzyme loadings. Similarly at 0.15 g mL(-1) solid loadings both high ethanol concentration (43.7 g L(-1)) and high ethanol yield (91.25%) were achieved. Regression analysis of experimental results shows that all process parameters had significant role on maximum ethanol production, glucose solubility, ethanol yield and ethanol volumetric productivity. SSF of SCW treated PBT biomass is economically feasible for production of bioethanol.