Recent Developments in Materials for Physical Hydrogen Storage: A Review.

The depletion of reliable energy sources and the environmental and climatic repercussions of polluting energy sources have become global challenges. Hence, many countries have adopted various renewable energy sources including hydrogen. Hydrogen is a future energy carrier in the global energy system and has the potential to produce zero carbon emissions. For the non-fossil energy sources, hydrogen and electricity are considered the dominant energy carriers for providing end-user services, because they can satisfy most of the consumer requirements. Hence, the development of both hydrogen production and storage is necessary to meet the standards of a "hydrogen economy". The physical and chemical absorption of hydrogen in solid storage materials is a promising hydrogen storage method because of the high storage and transportation performance. In this paper, physical hydrogen storage materials such as hollow spheres, carbon-based materials, zeolites, and metal-organic frameworks are reviewed. We summarize and discuss the properties, hydrogen storage densities at different temperatures and pressures, and the fabrication and modification methods of these materials. The challenges associated with these physical hydrogen storage materials are also discussed.

Nanocrystalline Cellulose-Supported Iron Oxide Composite Materials for High-Performance Lithium-Ion Batteries.

Nanocrystalline cellulose (NCC) can be converted into carbon materials for the fabrication of lithium-ion batteries (LIBs) as well as serve as a substrate for the incorporation of transition metal oxides (TMOs) to restrain the volume expansion, one of the most significant challenges of TMO-based LIBs. To improve the electrochemical performance and enhance the longer cycling stability of LIBs, a nanocrystalline cellulose-supported iron oxide (Fe2O3) composite (denoted as NCC-Fe2O3) is synthesized and utilized as electrodes in LIBs. The obtained NCC-Fe2O3 electrode exhibited stable cycling performance, better capacity, and high-rate capacity, and delivered a specific discharge capacity of 576.70 mAh g-1 at 100 mA g-1 after 1000 cycles. Moreover, the NCC-Fe2O3 electrode was restored and showed an upward trend of capacity after working at high current densities, indicating the fabricated composite is a promising approach to designing next-generation high-energy density lithium-ion batteries.

Development of Liquid Organic Hydrogen Carriers for Hydrogen Storage and Transport.

The storage and transfer of energy require a safe technology to mitigate the global environmental issues resulting from the massive application of fossil fuels. Fuel cells have used hydrogen as a clean and efficient energy source. Nevertheless, the storage and transport of hydrogen have presented longstanding problems. Recently, liquid organic hydrogen carriers (LOHCs) have emerged as a solution to these issues. The hydrogen storage technique in LOHCs is more attractive than those of conventional energy storage systems like liquefaction, compression at high pressure, and methods of adsorption and absorption. The release and acceptance of hydrogen should be reversible by LOHC molecules following favourable reaction kinetics. LOHCs comprise liquid and semi-liquid organic compounds that are hydrogenated to store hydrogen. These hydrogenated molecules are stored and transported and finally dehydrogenated to release the required hydrogen for supplying energy. Hydrogenation and dehydrogenation are conducted catalytically for multiple cycles. This review elaborates on the characteristics of different LOHC molecules, based on their efficacy as energy generators. Additionally, different catalysts used for both hydrogenation and dehydrogenation are discussed.

To stay or re-migrate after the pandemic shock? Labor re-migration intention to the coastal areas of Thua Thiên Hue province in Vietnam.

This study applied the extended theory of planned behavior (ETPB) to explore factors that shape the behavioral intention of migrant laborers returning to the coastal region of Thua Thiên Hue province during the peak of the COVID-19 pandemic to remigrate. Data collection included 210 interviews with returned migrants aged 18 and above in 4 coastal communes of Thua Thiên Hue province, in-depth interviews (8 key informants) and a group discussion (5 persons). Exploratory factor analysis and a multivariate linear regression model were applied to analyze the data. Results showed that in addition to individual socio-demographic characteristics (i.e. level of education, age, income level and sex), attitudes, subjective norms, perceived behavioral control, and perceived risk were also determinant factors of migrants' intention to remigrate. This research suggested that in order to build resilience of rural migration workers, related departments should seriously consider the following recommendations: (i) raise awareness and encourage young rural people to complete their education and necessary skills; (ii) organize related psychological training programs for rural laborers; (iii) raise awareness about the necessity to participate in social insurance; (iv) promote rural job creation programs suitable for low education and low-skilled rural laborers; (v) raise awareness for local people, particularly school children, about the value and opportunities of being smart farmers in the context of 4.0 technology and social risks at the destination for low education and low-skilled laborers; (vi) digitalize migration labor management and provide digital information services regarding job opportunities for rural laborers.

Novel Thiosemicarbazone Quantum Dots in the Treatment of Alzheimer's Disease Combining In Silico Models Using Fingerprints and Physicochemical Descriptors.

Searching for thiosemicarbazone derivatives with the potential to inhibit acetylcholinesterase for the treatment of Alzheimer's disease (AD) is an important current goal. The QSARKPLS, QSARANN, and QSARSVR models were constructed using binary fingerprints and physicochemical (PC) descriptors of 129 thiosemicarbazone compounds screened from a database of 3791 derivatives. The R 2 and Q 2 values for the QSARKPLS, QSARANN, and QSARSVR models are greater than 0.925 and 0.713 using dendritic fingerprint (DF) and PC descriptors, respectively. The in vitro pIC50 activities of four new design-oriented compounds N1, N2, N3, and N4, from the QSARKPLS model using DFs, are consistent with the experimental results and those from the QSARANN and QSARSVR models. The designed compounds N1, N2, N3, and N4 do not violate Lipinski-5 and Veber rules using the ADME and BoiLED-Egg methods. The binding energy, kcal mol-1, of the novel compounds to the 1ACJ-PDB protein receptor of the AChE enzyme was also obtained by molecular docking and dynamics simulations consistent with those predicted from the QSARANN and QSARSVR models. New compounds N1, N2, N3, and N4 were synthesized, and the experimental in vitro pIC50 activity was determined in agreement with those obtained from in silico models. The newly synthesized thiosemicarbazones N1, N2, N3, and N4 can inhibit 1ACJ-PDB, which is predicted to be able to cross the barrier. The DFT B3LYP/def-SV(P)-ECP quantization calculation method was used to calculate E HOMO and E LUMO to account for the activities of compounds N1, N2, N3, and N4. The quantum calculation results explained are consistent with those obtained in in silico models. The successful results here may contribute to the search for new drugs for the treatment of AD.

The Properties of Microwave-Assisted Synthesis of Metal-Organic Frameworks and Their Applications.

Metal-organic frameworks (MOF) are a class of porous materials with various functions based on their host-guest chemistry. Their selectivity, diffusion kinetics, and catalytic activity are influenced by their design and synthetic procedure. The synthesis of different MOFs has been of considerable interest during the past decade thanks to their various applications in the arena of sensors, catalysts, adsorption, and electronic devices. Among the different techniques for the synthesis of MOFs, such as the solvothermal, sonochemical, ionothermal, and mechanochemical processes, microwave-assisted synthesis has clinched a significant place in MOF synthesis. The main assets of microwave-assisted synthesis are the short reaction time, the fast rate of nucleation, and the modified properties of MOFs. The review encompasses the development of the microwave-assisted synthesis of MOFs, their properties, and their applications in various fields.

Glutathione Fluorescence Sensing Based on a Co-Doped Carbon Dot/Manganese Dioxide Nanocoral Composite.

Glutathione (GSH) is an antioxidant thiol that has a vital role in the pathogenesis of various human diseases such as cardiovascular disease and cancer. Hence, it is necessary to study effective methods of GSH evaluation. In our work, an effective GSH sensor based on a nitrogen and phosphorus co-doped carbon dot (NPCD)-MnO2 nanocoral composite was fabricated. In addition to utilizing the strong fluorescence of the NPCDs, we utilized the reductant ability of the NPCDs themselves to form MnO2 and then the NPCD-MnO2 nanocoral composite from MnO4-. The characteristics of the nanocoral composite were analyzed using various electron microscopy techniques and spectroscopic techniques. The overlap between the absorption spectrum of MnO2 and the fluorescence emission spectrum of the NPCDs led to effective fluorescence resonance energy transfer (FRET) in the nanocoral composite, causing a decrease in the fluorescent intensity of the NPCDs. A linear recovery of the fluorescent intensity of the NPCDs was observed with the GSH level raising from 20 to 250 µM. Moreover, our GSH sensor showed high specificity and sensing potential in real samples with acceptable results.

A Co-Doped Carbon Dot/Silver Nanoparticle Nanocomposite-Based Fluorescence Sensor for Metformin Hydrochloride Detection.

In this study, a fluorescence sensor based on nitrogen and phosphorus co-doped carbon dot/silver nanoparticle (NPCD/AgNP) nanocomposites was developed for metformin hydrochloride (MFH) detection. We first utilized the reducing nature of the NPCDs to prepare AgNPs from Ag+ and subsequently prepare NPCD/AgNP nanocomposites. The nanocomposite material was characterized by various methods, including electron microscopic methods (SEM and TEM), spectroscopic methods (UV-Vis, PL, FTIR, and XPS spectroscopy), light scattering (ELS), and XRD. Further, we utilized the enhanced fluorescence of the NPCDs as well as the overlap between the fluorescence emission spectrum of the NPCDs and the absorption spectrum of the AgNPs to use the NPCD/AgNP nanocomposites as an effective inner filter effect (IFE) pair for sensing MFH. The IFE between NPCDs and AgNPs in the nanocomposite material resulted in a significant quenching of the fluorescence intensity of the nanocomposites compared to that of the pure NPCDs. However, the fluorescence was recovered when MFH was introduced into the nanocomposite solution. The fluorescence intensity of the nanocomposites increased linearly as the MFH concentration increased from 2 to 100 µg/L. This detection method showed good sensitivity compared to other methods. It also showed high selectivity and high sensing potential for MFH in human serum and yielded acceptable results.

"Turn on" Fluorescence Sensor of Glutathione Based on Inner Filter Effect of Co-Doped Carbon Dot/Gold Nanoparticle Composites.

Glutathione (GSH) is a thiol that plays a significant role in nutrient metabolism, antioxidant defense and the regulation of cellular events. GSH deficiency is related to variety of diseases, so it is useful to develop novel approaches for GSH evaluation and detection. In this study we used nitrogen and phosphorus co-doped carbon dot-gold nanoparticle (NPCD-AuNP) composites to fabricate a simple and selective fluorescence sensor for GSH detection. We employed the reductant potential of the nitrogen and phosphorus co-doped carbon dots (NPCDs) themselves to form AuNPs, and subsequently NPCD-AuNP composites from Au3+. The composites were characterized by using a range of spectroscopic and electron microscopic techniques, including electrophoretic light scattering and X-ray diffraction. The overlap of the fluorescence emission spectrum of NPCDs and the absorption spectrum of AuNPs resulted in an effective inner filter effect (IFE) in the composite material, leading to a quenching of the fluorescence intensity. In the presence of GSH, the fluorescence intensity of the composite was recovered, which increased proportionally to increasing the GSH concentration. In addition, our GSH sensing method showed good selectivity and sensing potential in human serum with a limit of detection of 0.1 µM and acceptable results.

Highly Selective Fluorescence Sensor Based on Graphene Quantum Dots for Sulfamethoxazole Determination.

In our research, a reliable fluorescence sensor for the detection of sulfamethoxazole (SMZ) was developed. This method relies on graphene quantum dots (GQDs) entrapped in a silica molecularly imprinted polymer (GQDs@SMIP), which was synthesized by the polymerization using GQDs, SMZ, tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) as fluorescence material, template, cross-linker, and functional monomers, respectively. The GQDs@SMIP was characterized by fluorometry, Fourier-transform infrared spectroscopy, transmission and scanning electron microscopies, X-ray photoelectron spectroscopy, and powder X-ray diffraction. The GQDs@SMIP exhibited a good capacity to absorb SMZ from solution, which resulted in the quenching of the GQD fluorescence intensity. The intensity of GQDs@SMIP decreased linearly with the SMZ concentration in the range of 1 to 100 µM with a correlation coefficient of 0.99537. In addition, the fluorescence responses of GQDs@SMIP to interfering substances were investigated. The results indicated that there was no effect of interfering substances on SMZ detection. Thus, the highly selective GQDs@SMIP fluorescence sensor is an effective and promising device for SMZ detection and analysis.

Detection of Ferric Ions and Catecholamine Neurotransmitters via Highly Fluorescent Heteroatom Co-Doped Carbon Dots.

Carbon dots (CDs) demonstrate very poor fluorescence quantum yield (QY). In this study, with the help of a hydrothermal method, we combined CDs with nitrogen and phosphorus elements belonging to the VA group (in the periodic table) to form heteroatom co-doped CDs, i.e., nitrogen and phosphorus co-doped carbon dots (NPCDs). These displayed a significant improvement in the QY (up to 84%), which was as much as four times than that of CDs synthesized by the same method. The as-prepared NPCDs could be used as an "off-on" fluorescence detector for the rapid and effective sensing of ferric ions (Fe3+) and catecholamine neurotransmitters (CNs) such as dopamine (DA), adrenaline (AD), and noradrenaline (NAD). The fluorescence of NPCDs was "turned off" and the emission wavelength was slightly red-shifted upon increasing the Fe3+ concentration. However, when CNs were incorporated, the fluorescence of NPCDs was recovered in a short response time; this indicated that CN concentration could be monitored, relying on enhancing the fluorescence signal of NPCDs. As a result, NPCDs are considered as a potential fluorescent bi-sensor for Fe3+ and CN detection. Particularly, in this research, we selected DA as the representative neurotransmitter of the CN group along with Fe3+ to study the sensing system based on NPCDs. The results exhibited good linear ranges with a limit of detection (LOD) of 0.2 and 0.1 µM for Fe3+ and DA, respectively.

Polypyrrole/Graphene Quantum Dot Composites as a Sensor Media for Epinephrine.

In this paper, we discuss a new biosensor for simple and rapid detection of epinephrine (EP) based on polypyrrole/graphene quantum dot (PPy/GQD) composites. Presence of amine groups on the PPy backbone leads to surface passivation of GQDs. As a result, the composites exhibit strong fluorescence emission, which can be up to three times that of pristine GQDs. In neutral to alkaline solution, the EP on the surface of PPy/GQD composites is converted to a quinone, which triggers the fluorescence quenching of PPy/GQD composites via a photoinduced electron transfer process. Hence, the concentration of EP can be effectively monitored by measuring the variation in the fluorescence signal of PPy/GQD composites. The quenched fluorescence intensity of PPy/GQDs was proportional to the concentration of EP (0.7-400 µM). We used our method to determine the concentration of EP in human serum samples and obtained satisfactory results.

Estimation of methane emissions from local and crossbreed beef cattle in Daklak province of Vietnam.

OBJECTIVE: This study was aimed at evaluating effects of cattle breed resources and alternative mixed-feeding practices on meat productivity and emission intensities from household farming systems (HFS) in Daklak Province, Vietnam. METHODS: Records from Local Yellow×Red Sindhi (Bos indicus; Lai Sind) and 1/2 Limousin, 1/2 Drought Master, and 1/2 Red Angus cattle during the growth (0 to 21 months) and fattening (22 to 25 months) periods were used to better understand variations on meat productivity and enteric methane emissions. Parameters were determined by the ruminant model. Four scenarios were developed: (HFS1) grazing from birth to slaughter on native grasses for approximately 10 h plus 1.5 kg dry matter/d (0.8% live weight [LW]) of a mixture of guinea grass (19%), cassava (43%) powder, cotton (23%) seed, and rice (15%) straw; (HFS2) growth period fed with elephant grass (1% of LW) plus supplementation (1.5% of LW) of rice bran (36%), maize (33%), and cassava (31%) meals; and HFS3 and HFS4 computed elephant grass, but concentrate supplementation reaching 2% and 1% of LW, respectively. RESULTS: Results show that compared to HFS1, emissions (72.3±0.96 kg CH4/animal/life; least squares means± standard error of the mean) were 15%, 6%, and 23% lower (p<0.01) for the HFS2, HFS3, and HFS4, respectively. The predicted methane efficiencies (CO2eq) per kg of LW at slaughter (4.3±0.15), carcass weight (8.8±0.25 kg) and kg of edible protein (44.1±1.29) were also lower (p<0.05) in the HFS4. In particular, irrespective of the HSF, feed supply and ratio changes had a more positive impact on emission intensities when crossbred 1/2 Red Angus cattle were fed than in their crossbred counterparts. CONCLUSION: Modest improvements on feeding practices and integrated modelling frameworks may offer potential trade-offs to respond to climate change in Vietnam.

The evolving local social contract for managing climate and disaster risk in Vietnam.

How do disasters shape local government legitimacy in relation to managing climate- and disaster-related risks? This paper looks at how local authorities in Central Vietnam perceive their social contract for risk reduction, including the partial merging of responsibilities for disaster risk management with new plans for and investments in climate change adaptation and broader socioeconomic development. The findings indicate that extreme floods and storms constitute critical junctures that stimulate genuine institutional change. Local officials are proud of their strengthened role in disaster response and they are eager to boost investment in infrastructure. They have struggled to reinforce their legitimacy among their constituents, but given the shifting roles of the state, private sector, and civil society, and the undiminished emphasis on high-risk development models, their responsibilities for responding to emerging climate change scenarios are increasingly nebulous. The past basis for legitimacy is no longer valid, but tomorrow's social contract is not yet defined.

Factors associated with HIV viral load suppression on antiretroviral therapy in Vietnam.

BACKGROUND: Limited data are available on HIV viral suppression rates among men and women on antiretroviral therapy (ART) and factors associated with HIV RNA viral load (VL) suppression in Vietnam. METHODS: We conducted a cross-sectional survey of 1255 adult patients on ART for at least 1 year across four provinces in Vietnam. Data collection included a standardised questionnaire, routine laboratory testing, and an HIV VL assay. Bivariate and logistic multivariate analyses were conducted to assess viral suppression rates and factors associated with unsuppressed HIV VL. RESULTS: The median age was 34.5 years and the median time on ART was 46 months. Gender was 66% male (n=828) and 34% female (n=427). HIV viral suppression below 1000 copies/mL was 93%. Viral suppression among woman was not significantly different than among men (93.7% vs 92.9%; P=0.59). On multivariate analysis, unsuppressed HIV VL was independently associated with lower CD4 cell count, social isolation, high stigma, not receiving a single-tablet daily regimen, multiple late appointments in past year, and immunological failure. CONCLUSION: On-treatment viral load suppression rates in Vietnam are high and already exceed the UNAIDS 90% target for viral suppression on ART. Gender does not impact viral suppression rates of patients on ART in Vietnam. Access to routine viral load testing should be improved, adherence monitoring and counselling streamlined, and ART regimens simplified to maintain viral suppression rates, as more people start ART. Psychological and social factors are also associated with unsuppressed HIV VL, necessitating treatment support interventions to address social isolation and stigma among people living with HIV in Vietnam.