Isotope engineering achieved by local coordination design in Ti-Pd co-doped ZrCo-based alloys.

Deuterium/Tritium (D/T) handling in defined proportions are pivotal to maintain steady-state operation for fusion reactors. However, the hydrogen isotope effect in metal-hydrogen systems always disturbs precise D/T ratio control. Here, we reveal the dominance of kinetic isotope effect during desorption. To reconcile the thermodynamic stability and isotope effect, we demonstrate a quantitative indicator of Tgap and further a local coordination design strategy that comprises thermodynamic destabilization with vibration enhancement of interstitial isotopes for isotope engineering. Based on theoretical screening analysis, an optimized Ti-Pd co-doped Zr0.8Ti0.2Co0.8Pd0.2 alloy is designed and prepared. Compared to ZrCo alloy, the optimal alloy enables consistent isotope delivery together with a three-fold lower Tgap, a five-fold lower energy barrier difference, a one-third lower isotopic composition deviation during desorption and an over two-fold higher cycling capacity. This work provides insights into the interaction between alloy and hydrogen isotopes, thus opening up feasible approaches to support high-performance fusion reactors.

New insights into the process of intrinsic point defects in PuO2.

Intrinsic point defects are known to play a crucial role in determining the physical properties of solid-state materials. In this study, we systematically investigate the intrinsic point defects, including vacancies (VPu and VO), interstitials (Pui and Oi), and antisite atoms (PuO and OPu) in PuO2 using the first-principles plane wave pseudopotential method. Our calculations consider the whole charge state of these point defects, as well as the effect of oxygen partial pressure. This leads to a new perspective on the process of intrinsic point defects in PuO2. We find that the antisite atoms OPu and PuO are more likely to appear in O-rich and O-deficient environments, respectively. Interestingly, the most energetically favorable type of Schottky defect is {2VPu3-: 3VO2+} in an O-rich environment, while {4VO1+: VPu4-} is preferred in an O-deficient environment. These results differ from the commonly known {VPu4-: 2VO2+} type of Schottky defect. Moreover, under O-deficient conditions, we predict that the stable cation Frenkel defect is {VPu4+: Pui4+}, while the most stable anion Frenkel defect is {VO2+: Oi2-} under O-rich conditions. Lastly, we find that the only two types of antisite pairs that can appear are {OPu5-: PuO5+} and {OPu6-: PuO6+}, with the latter being the more stable configuration. These unconventional defect configurations provide a new viewpoint on the process of intrinsic point defects in PuO2 and lay theoretical foundations for future experiments.

Insights into the enhanced hydrogen adsorption on M/La2O3 (M = Ni, Co, Fe).

Lanthanum oxide (La2O3) possesses superior reactivity during catalytic hydrogenation, but the intrinsic activity of La2O3 toward H2 adsorption and activation remains unclear. In the present work, we fundamentally investigated hydrogen interaction with Ni-modified La2O3. Hydrogen temperature programmed desorption (H2-TPD) on Ni/La2O3 shows enhanced hydrogen adsorption with a new hydrogen desorption peak at a higher temperature position compared to that on the metallic Ni surfaces. By systematically exploring the desorption experiments, the enhanced H2 adsorption on Ni/La2O3 is due to the oxygen vacancies formed at the metal-oxide interfaces. Hydrogen atoms transfer from Ni surfaces to the oxygen vacancies to form lanthanum oxyhydride species (H-La-O) at the metal-oxide interfaces. The adsorbed hydrogen at the metal-oxide interfaces of Ni/La2O3 results in improved catalytic reactivity in CO2 methanation. Furthermore, the enhanced hydrogen adsorption on the interfacial oxygen vacancies is ubiquitous for La2O3-supported Fe, Co, and Ni nanoparticles. Benefiting from the modification effect of the supported transition metal nanoparticles, the surface oxyhydride species can be formed on La2O3 surfaces, which resembles the recently reported oxyhydride observed on the reducible CeO2 surfaces with abundant surface oxygen vacancies. These findings strengthen our understanding of the surface chemistry of La2O3 and shed new light on the design of highly efficient La2O3-based catalysts with metal-oxide interfaces.

Direct observation of highly effective hydrogen isotope separation at active metal sites by in situ DRIFT spectroscopy.

In situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was developed for the first time to observe the hydrogen isotope separation behavior at active CuI sites within CuI-MFU-4l, and clear evidence of the preferential adsorption of D2 over H2 was directly captured. More importantly, our results show direct spectral proof to clarify the chemical affinity quantum sieving mechanism of hydrogen isotope separation within porous adsorbents.

Comparative Ergonomic Study Examining the Work-Related Musculoskeletal Disorder Symptoms of Taiwanese and Thai Workers in a Tape Manufacturing Factory.

This study surveyed 114 Taiwanese and 57 Thai workers in a tape manufacturing factory in Taiwan and evaluated their symptoms of work-related musculoskeletal disorder (WMSD) and associated risk factors by using the revised Nordic Musculoskeletal Questionnaire. Task-appropriate biomechanical and body load assessment tools were also employed to examine biomechanical and body load during four specified daily tasks. The results indicated that the prevalence of discomfort symptoms in any body part within one year was 81.6% for the Taiwanese workers and 72.3% for the Thai workers. The body part in which the Taiwanese workers most frequently experienced discomfort was the shoulders (57.0%), followed by the lower back (47.4%), the neck (43.9%), and the knees (36.8%); where the Thai workers most frequently experienced discomfort was the hands or wrists (42.1%), followed by the shoulders (36.8%) and the buttocks or thighs (31.6%). These locations of discomfort were associated with task characteristics. Heavy-material handling (>20 kg) more than 20 times per day was the most significant risk factor for WMSDs for both groups, and this task must thus be urgently improved. We also suggest that providing wrist braces for Thai workers may assist in alleviating their hand and wrist discomfort. The biomechanical assessment results indicated that the compression forces acting on the workers' lower backs exceeded the Action Limit standard; administrative controls must thus be instituted for two heavy-material handling tasks. In the factory, some tasks and workers' movements when completing these tasks must be assessed and improved immediately by using appropriate tools. Although the Thai workers were engaged in more physically demanding tasks, their WMSDs were milder than those of the Taiwanese workers. The results of the study can serve as references for the prevention and reduction of WMSDs in local and foreign workers in similar industries.

The complete chloroplast genome of two Firmiana species and comparative analysis with other related species.

Firmiana is a small genus within the subfamily Sterculioideae of the Malvaceae. There are nine Firmiana species distributed in South and South-west China, most of which are endangered. Due to the shortage of plastid genomes data, the phylogenetic relationships and the evolutionary history of this genus remain unclear. Therefore, the complete chloroplast genomes of F. calcarean and F. hainanensis were sequenced using high-throughput sequencing and then compared with the chloroplast genomes of other reported Firmiana species. The genome size of F. calcarean and F. hainanensis is 161,263 and 160,031 bp long, respectively, containing a total of 131 genes (including 85 protein coding genes, 37 tRNAs, 8 rRNAs, and one pseudogene). Comparative analysis revealed that the genome structure, GC content, gene content and order, as well as the RNA editing sites within the chloroplast genomes of F. calcarean and F. hainanensis were similar to previously reported Firmiana species. ML phylogenetic analysis revealed that F. danxiaensis, F. hainanensis, F. calcarean, F. simplex, and F. major form a sister group to F. colorata, F. pulcherrima, and F. kwangsiensis. The SSRs, long repeats, and 21 highly divergent regions (Pi > 0.01) identified in this study might provide potential DNA markers for further population genetics and phylogenetic studies of Firmiana. Our findings can help design new species-specific molecular markers and the general framework to further explore the evolutionary history of Firmiana and to address their conservation challenges.

Monitoring and Modulating mtDNA G-Quadruplex Dynamics Reveal Its Close Relationship to Cell Glycolysis.

The mitochondrial DNA G-quadruplex (mtDNA G4) is a potential regulatory element for the regulation of mitochondrial functions; however, its relevance and specific roles in diseases remain largely unknown. Here, we engineered a set of chemical probes, including MitoISCH, an mtDNA G4-specific fluorescent probe, together with MitoPDS, a mitochondria-targeted G4-stabilizing agent, to thoroughly investigate mtDNA G4s. Using MitoISCH to monitor previously intractable dynamics of mtDNA G4s, we surprisingly found that their formation was prevalent only in endothelial and cancer cells that rely on glycolysis for energy production. Consistent with this, promotion of mtDNA G4 folding by MitoPDS in turn caused glycolysis-related gene activation and glycolysis enhancement. Remarkably, this close relationship among mtDNA G4s, glycolysis, and cancer cells further allowed MitoISCH to accumulate in tumors and label them in vivo. Our work reveals an unprecedented link between mtDNA G4s and cell glycolysis, suggesting that mtDNA G4s may be a novel cancer biomarker and therapeutic target deserving further exploration.

Low Concentration of Quercetin Reduces the Lethal and Sublethal Effects of Imidacloprid on Apis cerana (Hymenoptera: Apidae).

Large-scale use of systemic pesticides has been considered a potential factor for pollinator population decline. Phytochemicals, e.g., quercetin, have been demonstrated to increase the pesticide tolerance of Apis mellifera Linnaeus (Hymenoptera: Apidae), which is helpful to develop strategies to reduce the pesticides hazards to pollinators. In this study, we hypothesized phytochemicals could reduce the detrimental effects of imidacloprid on Apis cerana Fabricius. The lethal and sublethal effects of imidacloprid on A. cerana workers were investigated. The results showed that A. cerana workers chronically exposed to 100 µg/liter imidacloprid had a significantly shorter longevity by 10.81 d compared with control. Acute exposure to imidacloprid at 100 µg/liter impaired the sucrose responsiveness and memory retention of the workers, and 20 µg/liter reduced the sucrose responsiveness. The treatment with 37.8 mg/liter quercetin for 24 h could increase the longevity of A. cerana workers when chronically exposed to 100 µg/liter imidacloprid, and 75.6 mg/liter quercetin feeding treatment alleviated the impairment of sucrose responsiveness. However, workers treated with 151.2 mg/liter and 75.6 mg/liter quercetin had a significantly shorter longevity compared to that of bees chronically exposed to 100 µg/liter imidacloprid without quercetin treatment. Our results suggested that quercetin treatment could produce a biphasic influence on the lethal effects of imidacloprid on A. cerana. Quercetin at 37.8 mg/liter and 75.6 mg/liter in the diet before pesticide exposure was able to reduce the lethal and sublethal effects of imidacloprid, respectively, providing potential strategies to reduce the pesticides hazards to native honey bees (A. cerana).

Flower-like Hollow MoSe2 Nanospheres as Efficient Earth-Abundant Electrocatalysts for Nitrogen Reduction Reaction under Ambient Conditions.

Electrocatalytic nitrogen reduction reaction (NRR) is a green and sustainable strategy for artificial nitrogen fixation but remains a significant challenge because of the lack of high-performance electrocatalysts. In this study, flower-like hollow MoSe2 nanospheres as efficient earth-abundant NRR electrocatalysts with a high faradaic efficiency of 14.2% and an ammonia yield of 11.2 µg h-1 mgcat.-1 at ambient conditions were prepared. Such excellent NRR activity can be attributed to the higher specific surface area, more active sites, and longer N2 retention time within the shells because of the design of the hollow structure. Density functional theory calculations were performed to further understand the catalytic mechanism involved. This work demonstrates the feasibility of transition-metal selenides as NRR electrocatalysts and suggests an electrocatalyst materials structure design for efficient electrochemical nitrogen fixation.

Platinum Single Atoms Supported on Nanoarray-Structured Nitrogen-Doped Graphite Foil with Enhanced Catalytic Performance for Hydrogen Evolution Reaction.

Platinum-based single-atom catalysts (SACs) are among the most promising candidates for the practical applications of electrochemical hydrogen evolution reaction (HER), but their catalytic efficiency remains to be further enhanced. Herein, a well-designed nanoarray-structured nitrogen-doped graphite foil (NNGF) substrate is introduced to support Pt SACs in Pt-N4 construction (Pt1/NNGF) for HER. Within NNGF, the constructed nanoarray-structured surficial layer for supporting Pt SACs could enhance the exposure of active sites to the electrolyte and improve the reaction and diffusion kinetics; meanwhile, the retained graphite structures in bulk NNGF provide not only the required electrical conductivity but also the mechanical stability and flexibility. Because of such double-layer structures of NNGF, stable Pt-N4 construction, and binder-free advantages, the Pt1/NNGF electrode exhibits a low overpotential of 0.023 V at 10 mA cm-2 and a small Tafel slope of 29.1 mV dec-1 as well as an excellent long-term durability.

Adsorption and dissociation behavior of H2 on PuH2 (100), (110) and (111) surfaces: a density functional theory+U study.

The density functional theory (DFT) and DFT plus correction for on-site Coulomb interaction (DFT+U) method were performed to investigate the adsorption and dissociation of H2 on PuH2 (100), (110) and (111) surfaces. Overall, the H2 molecule can be adsorbed on the PuH2 surface without spontaneous dissociation. The calculated H-H bond lengths (R H-H) are all elongated to different degrees, and the R H-H at different adsorption sites is about 0.84-4.21% longer than in the gas phase. We found that the dissociation of H2 on the (110) surface is a spontaneous exothermic process, and a total energy of 0.60 eV is released in the whole process. The smaller barriers corroborate that the migration of an H atom on the PuH2 surface is possible, and even spontaneous diffusion may occur. The spontaneous migration of a hydrogen atom adsorbed on the (110) surface from the surface to the interior promotes the conversion of PuH2 to PuH3, which may be the fundamental driving force of hydrogenation corrosion. Our results provide useful information to explain the mechanism of hydrogenation corrosion on the PuH2 surface.

Effectiveness and Safety of an Inactivated Enterovirus 71 Vaccine in Children Aged 6-71 Months in a Phase IV Study.

BACKGROUND: Evaluation of a licensed inactivated enterovirus type 71 (EV71) vaccine is needed in a phase IV study with a large population to identify its effectiveness and safety for further application. METHODS: An open-label, controlled trial involving a large population of 155 995 children aged 6-71 months was performed; 40 724 were enrolled in the vaccine group and received 2 doses of inactivated EV71 vaccine at an interval of 1 month, and the remaining children were used as the control group. The EV71-infected cases with hand, foot, and mouth disease were monitored in the vaccine and control groups during a follow-up period of 14 months since the 28th day postinoculation through the local database of the Notifiable Infectious Diseases Network. The effectiveness of the vaccine was estimated by comparing the incidence density in the vaccine group versus that in the control group based upon EV71-infected patients identified via laboratory testing. In parallel, the active and passive surveillance for safety of the vaccine was conducted by home or telephone visits and by using the Adverse Event Following Immunization (AEFI) system, respectively. RESULTS: An overall level of 89.7% (95% confidence interval, 24.0-98.6%) vaccine effectiveness against EV71 infection and a 4.58% rate of reported adverse events were observed. Passive surveillance demonstrated a 0.31% rate of reported common minor reactions. CONCLUSIONS: The clinical protection and safety of the EV71 vaccine were demonstrated in the immunization of a large population. CLINICAL TRIALS REGISTRATION: NCT03001986.

One-Step Synthesis of NiFe Layered Double Hydroxide Nanosheet Array/N-Doped Graphite Foam Electrodes for Oxygen Evolution Reactions.

Developing cost-effective and highly efficient oxygen evolution reaction (OER) electrocatalysts is vital for the production of clean hydrogen by electrocatalytic water splitting. Here, three dimensional nickel-iron layered double hydroxide (NiFe LDH) nanosheet arrays are in-situ fabricated on self-supporting nitrogen doped graphited foam (NGF) via a one-step hydrothermal process under an optimized amount of urea. The as prepared NiFe LDH/NGF electrode exhibits a remarkable activity toward OER with a low onset overpotential of 233 mV and a Tafel slope of 59.4 mV dec-1 as well as a long-term durability. Such good performance is attributed to the synergy among the doping effect, the binder-free characteristic, and the architecture of the nanosheet array.

Development of a Smart Fluorescent Sensor That Specifically Recognizes the c-MYC G-Quadruplex.

The specific sensing of an exact G-quadruplex structure by small molecules has never been reported. A fluorescent sensor based on the photoinduced electron transfer (PeT) mechanism provides possibilities for such specific, one-to-one recognition, indicated by fluorescence. We have rationally developed a PeT fluorescent sensor IZFL-2 by linking triarylimidazole and fluorescein moieties. IZFL-2 is a distinctive, smart sensor whose fluorescence is tunable by its molecular conformations. We then applied IZFL-2 to sensing G-quadruplexes and found that it could exactly distinguish the wild-type c-MYC G-quadruplex from other types of G-quadruplexes, as shown by the activation of its fluorescence. To understand this behavior, we performed various experiments, including fluorescence assays, absorption assays, and multiscale molecular dynamics simulations, to thoroughly investigate the optimal binding mode of IZFL-2 in the c-MYC G-quadruplex. Then, the corresponding HOMO-LUMO of IZFL-2 was analyzed, and the results demonstrated that the PeT process of IZFL-2 is suppressed only in the wild-type c-MYC G-quadruplex via specific loop interactions, which restores its fluorescence. To our knowledge, this smart molecule provides the first example of and new insights into the development of sensors specific for a particular G-quadruplex structure by utilizing intramolecular PeT-controlled fluorescence switching.

The complete chloroplast genome of Firmiana danxiaensis, an endangered species endemic to Danxia landform in Southern China.

We sequenced the complete chloroplast of Firmiana danxiaensis (Malvaceae), which is 161,253 bp in size and consists of a large single-copy region (LSC) of 90,142 bp and a short single copy region (SSC) of 20,067 bp. It was separated by two inverted repeats (IRs) regions of 25,522 bp for each. The GC content of the whole genome, LSC, SSC, and IRs region was 36.87%, 34.68%, 31.24%, and 42.97%, respectively. The overall base content was A (31.07%), T (32.05%), C (18.80%), and G (18.08%). The genome contained 127 genes, including 82 protein-coding sequences, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis showed that F. danxiaensis is sister to F. simplex, and supported there was a close relationship among F. danxiaensis, F. simplex, and F. pulcherrima.

Identification of G-Quadruplex-Binding Protein from the Exploration of RGG Motif/G-Quadruplex Interactions.

The arginine/glycine-rich region termed the RGG domain is usually found in G-quadruplex (G4)-binding proteins and is important in G4-protein interactions. Studies on the binding mechanism of RGG domains found that small segments (RGG motif) inside the domain contribute greatly to the G4 binding affinity. However, unlike the entire RGG domains that have been broadly explored, the role of the RGG motif remains obscure, with very limited study. Herein, to clarify the role of the RGG motif in G4-protein interactions, we systematically investigated the binding affinity and mode between RGG-motif peptides and G4s. The internal arrangement of RGG repeats and gap amino acids played a more crucial role in the G4-binding mechanism than a critical number of RGG repeats. Arginines and phenylalanines at the exact position of the RGG motif might enable additional hydrogen bonding and π-stacking interaction with nucleobases and strengthen the binding of G4. Impressively, proceeding from a G4-binding RGG peptide, 12, discovered above, we identified the cold-inducible RNA-binding protein (CIRBP) as a new G4 DNA-binding protein both in vitro and in cells. In addition, we found that the key amino acids for G4 binding in peptide 12 and CIRBP were highly similar, and peptide 12 clearly played a key role in the G4 binding of CIRBP. This report is the first in which a G4-binding protein was identified from exploration of the G4-binding RGG motif. Our findings suggest a novel strategy for discovering new G4-binding proteins by exploring key peptide segments.

A practical wide-field Raman imaging method with high spectral and spatial resolution.

Raman imaging has a great advantage in characterizing inhomogeneous systems. A practical wide-field Raman imaging platform is developed that shows major improvements on imaging speed, sensitivity, and resolution. Different from the traditional Raman imaging systems using the wavelength-fixed lasers and the chromatic dispersion devices, this system adopts an inverted architecture, integrated with a tunable laser and the wavelength-fixed filters. Owing to the high transmission of the fixed filters, the imaging sensitivity can be improved 5-10 times in comparison to the present wide-field Raman imaging setups using liquid-crystal tunable filters. Via combining with the high-power tunable laser, Raman images could be obtained in minutes and the Raman shift of the images could be tuned easily and accurately. The resolution of this system can reach 1.5 cm-1 in the spectrum and 490 nm in space, which could provide more fingerprint details of the analytes. This effective Raman imaging method allowing us to see chemical spatial variations on microscale is anticipated to be widely applied in scientific research fields.

[Research on the Efficacy of Fulfillment of Medical Device Adverse Event Monitoring Entities and Safeguard Mechanism].

OBJECTIVES: To solve the problem that medical device adverse event monitoring entities perform their duties inadequately, to provide reference for perfecting the post-market surveillance system. METHODS: Through theoretical and empirical research, the paper explored the ways to improve the performance of monitoring the adverse events of medical devices. RESULTS: The survey found that the number of adverse event monitoring reports was few and the quality of report was poor. The root causes included lack of motivation of monitoring entities, the imperfect monitoring system, and the monitoring capability failure, etc. CONCLUSIONS: The methods such as strengthening the main body responsibility consciousness, establishing evaluation system and accountability system, building social work network, are beneficial to the adverse events monitoring.

Structural and Kinetic Hydrogen Sorption Properties of Zr0.8Ti0.2Co Alloy Prepared by Ball Milling.

The effects of ball milling on the hydrogen sorption kinetics and microstructure of Zr0.8Ti0.2Co have been systematically studied. Kinetic measurements show that the hydrogenation rate and amount of Zr0.8Ti0.2Co decrease with increasing the ball milling time. However, the dehydrogenation rate accelerates as the ball milling time increases. Meanwhile, the disproportionation of Zr0.8Ti0.2Co speeds up after ball milling and the disproportionation kinetics is clearly inclined to be linear with time at 500°C. It is found from X-ray powder diffraction (XRD) results that the lattice parameter of Zr0.8Ti0.2Co gradually decreases from 3.164 Å to 3.153 Å when the ball milling time extends from 0 h to 8 h, which is mainly responsible for the hydrogen absorption/desorption behaviors. In addition, scanning electron microscope (SEM) images demonstrate that the morphology of Zr0.8Ti0.2Co has obviously changed after ball milling, which is closely related to the hydrogen absorption kinetics. Besides, high-resolution transmission electron microscopy (HRTEM) images show that a large number of disordered microstructures including amorphous regions and defects exist after ball milling, which also play an important role in hydrogen sorption performances. This work will provide some insights into the principles of how to further improve the hydrogen sorption kinetics and disproportionation property of Zr0.8Ti0.2Co.

Studies of Product Structure Adjustment Routes for China's Pharmaceutical Industry: A View From the New Healthcare Reform Targets.

BACKGROUND: The 12th Five-Year Plan period is a critical period for the development of the pharmaceutical industry in China. A major focus coming with the New Healthcare Reform is a product structure adjustment in the pharmaceutical industry. Many researchers have been attracted in recent years to product structure adjustment studies. METHODS: An empirical analysis of resources of the New Healthcare Reform was conducted by employing clustering analysis. A panel data model was established, with independent variables consisting of the city residents' medical insurance fund, drug fees per capita, city medical insurance fees per capita, rural medical insurance fees per capita, and number of people benefiting from the new rural cooperative medical scheme and the dependent variable being China's medical technology advancement fees. This study covered 29 provinces and regions and used panel data from 2007 to June 2012 to establish a fundamental regression equation for quantitative analysis. RESULTS: The city residents' medical insurance fund, rural medical insurance fees, and the new rural cooperative medical scheme are significant factors for pharmaceutical structure adjustment in China. The rural medical services market is the most important target market for pharmaceutical industrial transformation. CONCLUSION: The fundamental drug system and medical insurance system, which the New Healthcare Reform focuses upon, are closely related to the pharmaceutical product structure. For entities in which structural adjustment is not autonomous, changes can be achieved through sound coordination between organizational structure, technical structure, and repeated evaluation of consistency of drug product quality and overseas technical license.