Pt Single Atoms Supported on Defect Ceria as an Active and Stable Dual-Site Catalyst for Alkaline Hydrogen Evolution.

This work evaluates the feasibility of alkaline hydrogen evolution reaction (HER) using Pt single-atoms (1.0 wt %) on defect-rich ceria (Pt1/CeOx) as an active and stable dual-site catalyst. The catalyst displayed a low overpotential and a small Tafel slope in an alkaline medium. Moreover, Pt1/CeOx presented a high mass activity and excellent durability, competing with those of the commercial Pt/C (20 wt %). In this picture, the defective CeOx is active for water adsorption and dissociation to create H* intermediates, providing the first site where the reaction occurs. The H* intermediate species then migrate to adsorb and react on the Pt2+ isolated atoms, the site where H2 is formed and released. DFT calculations were also performed to obtain mechanistic insight on the Pt1/CeOx catalyst for the HER. The results indicate a new possibility to improve the state-of-the-art alkaline HER catalysts via a combined effect of the O vacancies on the ceria support and Pt2+ single atoms.

Mutual Information and Correlations across Topological Phase Transitions in Topologically Ordered Graphene Zigzag Nanoribbons.

Graphene zigzag nanoribbons, initially in a topologically ordered state, undergo a topological phase transition into crossover phases distinguished by quasi-topological order. We computed mutual information for both the topologically ordered phase and its crossover phases, revealing the following results: (i) In the topologically ordered phase, A-chirality carbon lines strongly entangle with B-chirality carbon lines on the opposite side of the zigzag ribbon. This entanglement persists but weakens in crossover phases. (ii) The upper zigzag edge entangles with non-edge lines of different chirality on the opposite side of the ribbon. (iii) Entanglement increases as more carbon lines are grouped together, regardless of the lines' chirality. No long-range entanglement was found in the symmetry-protected phase in the absence of disorder.

Living Cationic Ring-Opening Polymerization of Hetero Diels-Alder Adducts to Give Multifactor-Controlled and Fast-Photodegradable Vinyl Polymers.

Precise control of multiple structural parameters associated with vinyl polymers is important for producing materials with the desired properties and functions. While the development of living polymerization methods has provided a way to control the various structural parameters of vinyl polymers, the concomitant control of their sequence and regioregularity remains a challenging task. To overcome this challenge, herein, we report the living cationic ring-opening polymerization of hetero Diels-Alder adducts. The scalable and modular synthesis of the cyclic monomers was achieved by a one-step protocol using readily available vinyl precursors. Subsequently, living polymerization of the cyclic monomers was examined, allowing the synthesis of vinyl polymers while controlling multiple factors, including molecular weight, dispersity, alternating sequence, head-to-head regioregularity, and end-group functionality. The living characteristics of the developed method were further demonstrated by block copolymerization. The synthesized vinyl polymers exhibited unique thermal properties and underwent fast photodegradation even under sunlight.

Recent Advances in Diversity-Oriented Polymerization Using Cu-Catalyzed Multicomponent Reactions.

Diversification of polymer structures is important for imparting various properties and functions to polymers, so as to realize novel applications of these polymers. In this regard, diversity-oriented polymerization (DOP) is a powerful synthetic strategy for producing diverse and complex polymer structures. Multicomponent polymerization (MCP) is a key method for realizing DOP owing to its combinatorial features and high efficiency. Among the MCP methods, Cu-catalyzed MCP (Cu-MCP) has recently paved the way for DOP by overcoming the synthetic challenges of the previous MCP methods. Here the emergence and progress of Cu-MCP, its current challenges, and future perspectives are discussed.

Self-Catalytic Growth of Elementary Semiconductor Nanowires with Controlled Morphology and Crystallographic Orientation.

While the orientation-dependent properties of semiconductor nanowires have been theoretically predicted, their study has long been overlooked in many fields owing to the limits to controlling the crystallographic growth direction of nanowires (NWs). We present here the orientation-controlled growth of single-crystalline germanium (Ge) NWs using a self-catalytic low-pressure chemical vapor deposition process. By adjusting the growth temperature, the orientation of growth direction in GeNWs was selectively controlled to the ⟨110⟩, ⟨112⟩, or ⟨111⟩ directions on the same substrate. The NWs with different growth directions exhibit distinct morphological features, allowing control of the NW morphology from uniform NWs to nanoribbon structures. Significantly, the VLS-based self-catalytic growth of the ⟨111⟩ oriented GeNW suggests that NW growth is possible for single elementary materials even without an appropriate external catalyst. Furthermore, these findings could provide opportunities to investigate the orientation-dependent properties of semiconductor NWs.

Crystal Structures of the Plant Phospholipase A1 Proteins Reveal a Unique Dimerization Domain.

Phospholipase is an enzyme that hydrolyzes various phospholipid substrates at specific ester bonds and plays important roles such as membrane remodeling, as digestive enzymes, and the regulation of cellular mechanism. Phospholipase proteins are divided into following the four major groups according to the ester bonds they cleave off: phospholipase A1 (PLA1), phospholipase A2 (PLA2), phospholipase C (PLC), and phospholipase D (PLD). Among the four phospholipase groups, PLA1 has been less studied than the other phospholipases. Here, we report the first molecular structures of plant PLA1s: AtDSEL and CaPLA1 derived from Arabidopsis thaliana and Capsicum annuum, respectively. AtDSEL and CaPLA1 are novel PLA1s in that they form homodimers since PLAs are generally in the form of a monomer. The dimerization domain at the C-terminal of the AtDSEL and CaPLA1 makes hydrophobic interactions between each monomer, respectively. The C-terminal domain is also present in PLA1s of other plants, but not in PLAs of mammals and fungi. An activity assay of AtDSEL toward various lipid substrates demonstrates that AtDSEL is specialized for the cleavage of sn-1 acyl chains. This report reveals a new domain that exists only in plant PLA1s and suggests that the domain is essential for homodimerization.

Valorization of Click-Based Microporous Organic Polymer: Generation of Mesoionic Carbene-Rh Species for the Stereoselective Synthesis of Poly(arylacetylene)s.

This work reports the functionalization of azide-alkyne click-based microporous organic polymer (CMOP). The generation of triazolium salts and successive deprotonation induced mesoionic carbene species in hollow CMOP (H-CMOP). Rh(I) species could be coordinated to the mesoionic carbene species to form H-CMOP-Rh, showing excellent heterogeneous catalytic performance in the stereoselective polymerization of arylacetylenes.

Low-Power Scan Correlation-Aware Scan Cluster Reordering for Wireless Sensor Networks.

Cryptographic circuits generally are used for applications of wireless sensor networks to ensure security and must be tested in a manufacturing process to guarantee their quality. Therefore, a scan architecture is widely used for testing the circuits in the manufacturing test to improve testability. However, during scan testing, test-power consumption becomes more serious as the number of transistors and the complexity of chips increase. Hence, the scan chain reordering method is widely applied in a low-power architecture because of its ability to achieve high power reduction with a simple architecture. However, achieving a significant power reduction without excessive computational time remains challenging. In this paper, a novel scan correlation-aware scan cluster reordering is proposed to solve this problem. The proposed method uses a new scan correlation-aware clustering in order to place highly correlated scan cells adjacent to each other. The experimental results demonstrate that the proposed method achieves a significant power reduction with a relatively fast computational time compared with previous methods. Therefore, by improving the reliability of cryptography circuits in wireless sensor networks (WSNs) through significant test-power reduction, the proposed method can ensure the security and integrity of information in WSNs.

Non-exercise based estimation of cardiorespiratory fitness is inversely associated with metabolic syndrome in a representative sample of Korean adults.

BACKGROUND: This study investigated the association between non-exercise based estimation of cardiorespiratory fitness (eCRF) and metabolic syndrome (Mets) in Korean adults aged 18 years and older (13,400 women and 9885 men). METHODS: Data from the 2008 and 2011 Korea National Health and Nutrition Examination Surveys IV and V in South Korea were analyzed. eCRF was assessed with a previously validated procedure. Participants were classified into 5 categories from the lowest quantile to the highest quantile based on individual eCRF distributions. RESULTS: The findings showed an independent and inverse association between eCRF and Mets in women and men separately. Individuals in the highest eCRF category (quantile 5) had a significantly lower prevalence of Mets (14.5 and 14.8% for women and men, respectively) compared with their counterparts (40.4 and 46.4% for women and men, respectively) in the lowest eCRF category (quantile 1), and the association showed a graded response, with the quantiles 2, 3, and 4 also significantly associated with a lower prevalence of Mets compared with the quantile 1. Furthermore, the prevalence of Mets in the highest quantile compared with the lowest quantile remained statistically significant in both men (p < 0.05) and women (p < 0.05) even after adjustments for age, body mass index, skeletal muscle index, smoking, heavy drinking, vitamin D, caloric intake, and dietary intakes of carbohydrates, fats, and proteins. CONCLUSION: The findings support a preventive role for eCRF against Mets in Korean adults.

Development of a new 15-valent pneumococcal conjugate vaccine (PCV15) and evaluation of its immunogenicity.

A new 15-valent pneumococcal conjugate vaccine (PCV15) against serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 11A, 14, 18C, 19A, 19F, 22F, and 23F has been developed using aluminum phosphate as an adjuvant. Using the rabbit model, immunogenicity of each serotype was evaluated by measuring antigen specific antibodies and functional antibody titers and comparing them to a control vaccine, Prevnar13®. Among the shared serotypes in both PCV15 and Prevnar13®, Type 3 and 23F in PCV15 exhibited a lower opsonic index than Prevnar13®. Conversely, the other types showed greater or nearly the same immunogenic effects. Type 11A and 22F are two additional serotypes included in PCV15, and only 22F showed a reasonable opsonic index compared with other types. Type 11A exhibited a basal level fold-increase in OPA; thus, we further optimized 11A as well as 3 and 23F by controlling the polysaccharide-to-protein conjugation ratio as a variable. Antibody levels and functional antibody activities were evaluated by ELISA and OPA, and improved levels of immunogenic activities were observed for all three serotypes. In this study, we propose a new PCV15 candidate, in which the common 13 serotypes and a licensed control vaccine have equivalent efficacy while two additional serotypes showed adequate immunogenicity in the rabbit model.

Handgrip strength, depression, and all-cause mortality in Korean older adults.

BACKGROUND: Decreased muscle strength and/or depression with aging are emerging as important public health concerns in both developed and developing countries. This study investigated the effects of low handgrip strength (HGS) and depression on the risk of all-cause mortality in Korean older adults. METHODS: Data from 13,901 Korean adults (57% women) who participated in the 2008 baseline survey and completed the 2011 follow-up assessments were used. RESULTS: In total, the current findings showed that individuals with depression only and individuals with low HGS plus depression had significantly higher risks of all-cause mortality (hazard ratio (HR) = 1.366, 95% confidence interval (CI) = 1.033-1.807, p = 0.029 and HR = 1.961, 95% CI = 1.409-2.736, p < 0.001, respectively) even after adjustments for all the measured covariates, compared with individuals with high HGS plus no depression (HR = 1). Gender-stratified analysis showed that men with depression only and men with depression plus low HGS had significantly higher risks of all-cause mortality (HR = 1.376, 95% CI =1.029-1.841, p = 0.031 and HR = 1.861, 95% CI = 1.306-2.651, p = 0.001, respectively) even after adjustments for all the measured covariates, compared with individuals with no depression plus high HGS (HR = 1). In women, however, the joint effect of depression and low HGS only remained significant at borderline (HR = 2.603, 95% CI = 0.981-6.908, p = 0.055) when adjusted for all the confounders. CONCLUSION: The current finding suggested that depression and low HGS were significantly and synergistically associated with the increased risk of premature death from all causes in the Korean geriatric population.

A Rational Design of Highly Controlled Suzuki-Miyaura Catalyst-Transfer Polycondensation for Precision Synthesis of Polythiophenes and Their Block Copolymers: Marriage of Palladacycle Precatalysts with MIDA-Boronates.

Herein, we report a highly efficient Suzuki-Miyaura catalyst-transfer polycondensation (SCTP) of 3-alkylthiophenes using bench-stable but highly active Buchwald dialkylbiarylphospine Pd G3 precatalysts and N-methylimidodiacetic (MIDA)-boronate monomers. Initially, the feasibility of the catalyst-transfer process was examined by screening various dialkylbiarylphospine-Pd(0) species. After optimizing a small molecule model reaction, we identified both RuPhos and SPhos Pd G3 precatalysts as excellent catalyst systems for this purpose. On the basis of these model studies, SCTP was tested using either RuPhos or SPhos Pd G3 precatalyst, and 5-bromo-4- n-hexylthien-2-yl-pinacol-boronate. Poly(3-hexylthiophene) (P3HT) was produced with controlled molecular weight and narrow dispersity for a low degree of polymerization (DP) only, while attempts to synthesize P3HT having a higher DP with good control were unsuccessful. To improve the control, slowly hydrolyzed 5-bromo-4- n-hexylthien-2-yl-MIDA-boronate was introduced as a new monomer. As a result, P3HT and P3EHT (up to 17.6 kg/mol) were prepared with excellent control, narrow dispersity, and excellent yield (>90%). Detailed mechanistic investigation using 31P NMR and MALDI-TOF spectroscopy revealed that both fast initiation using Buchwald precatalysts and the suppression of protodeboronation due to the protected MIDA-boronate were crucial to achieve successful living polymerization of P3HT. In addition, a block copolymer of P3HT- b-P3EHT was prepared via SCTP by sequential addition of each MIDA-boronate monomer. Furthermore, the same block copolymer was synthesized by one-shot copolymerization for the first time by using fast propagating pinacol-boronate and slow propagating MIDA-boronate.

Endo and Exo Diels-Alder Adducts: Temperature-Tunable Building Blocks for Selective Chemical Functionalization.

The development and application of a novel endo furan-protected maleimide building block is reported. The endo isomer undergoes deprotection at temperatures ∼50 °C below the exo derivative. This enables a simple and powerful approach to quantitatively and selectively introduce functional maleimide groups via temperature modulation.

Enhanced luminescence of CsPbBr3 perovskite nanocrystals on stretchable templates with Au/SiO2 plasmonic nanoparticles.

We propose stretchable plasmonic templates of Au and Au/SiO2 nanoparticles (NPs) to improve the luminescence of CsPbBr3 perovskite nanocrystals (PNCs). These templates are highly flexible and consist of polymer-metal NP composites that facilitate the luminescence enhancement by localized surface plasmons (LSPs) due to coupling with metal NP. This template also prevents the degradation of carrier transport properties for perovskite light-emitting diodes by embedding metal NPs in polymer. The luminescence of PNC film on the template with Au NPs decreases by 21% compared to PNC films on the reference (polymer film without metal NPs), while it increases by 54% for the templates with Au/SiO2 NPs. The observed effects are explained by the luminescence enhancement due to coupling to LSPs formed by the Au/SiO2 NPs and by the prevalence of electron tunneling and dumping for Au NPs.

Physical activity and all-cause mortality in Korean older adults.

BACKGROUND: The association between physical activity (PA) and all-cause mortality may be modulated by potential confounders. AIM: To investigate the association between weekly PA and all-cause mortality in a population-based prospective study. SUBJECTS AND METHODS: The study sample included Korean older adults aged 60 years and older who participated in baseline assessments (n = 15 416) in 2008 and completed follow-up visits in 2011 (n = 14,976). Primary outcome was 3-year all-cause mortality. RESULTS: Compared with sufficiently active individuals (with Hazard Ratio (HR) = 1), completely inactive and insufficiently active individuals had a significantly higher risk of all-cause mortality (HR = 2.086, 95% CI = 1.639-2.655, p < 0.00 and HR = 1.644, 95% CI = 1.013-2.668, p = 0.044, respectively), even after adjustments for age and sex, health-related behaviour factors (i.e. smoking, alcohol intake and nutritional risk), cognitive impairment and components of frailty phenotype (i.e. involuntary weight loss, exhaustion and slowness). In addition, the inverse association between PA and all-cause mortality is differently modulated by potential confounders, including age, sex, smoking, depressive symptoms, cognitive impairment and involuntary weight loss. CONCLUSION: PA was inversely and independently associated with all-cause mortality in Korean older adults.

NHX-5, an Endosomal Na+/H+ Exchanger, Is Associated with Metformin Action.

Diabetes is one of the most impactful diseases worldwide. The most commonly prescribed anti-diabetic drug is metformin. In this study, we identified an endosomal Na(+)/H(+) exchanger (NHE) as a new potential target of metformin from an unbiased screen in Caenorhabditis elegans The same NHE homolog also exists in flies, where it too mediates the effects of metformin. Our results suggest that endosomal NHEs could be a metformin target and provide an insight into a novel mechanism of action of metformin on regulating the endocytic cycle.

Crystal structure of the PDZ domain of mouse Dishevelled 1 and its interaction with CXXC5.

Dishevelled (Dvl) plays a crucial role in Wnt signaling by interacting with membrane-bound receptors and downstream molecules through its PDZ domain. CXXC5 is one of the key molecules that interacts with Dvl and negatively regulates the Wnt/ß-catenin pathway in osteoblast differentiation. Recently, the Dvl-CXXC5 interaction has been identified as an excellent target for osteoporosis treatment. Therefore, it is desirable to have detailed structural information for the Dvl-CXXC5 interaction. Although solution structures of the Dvl1 PDZ domain have been reported, a high-resolution crystal structure would provide detailed sidechain information that is essential for drug development. Here, we determined the first crystal structure of the Dvl-1 PDZ domain at a resolution of 1.76 Å, and compared it with its previously reported solution structure. The Dvl1 PDZ domain crystal belonged to the space group H32 with unit-cell parameters a = b = 72.837, c = 120.616, α = ß = 90.00, γ = 120.00. The crystal structure of Dvl1 PDZ shared its topology with the previously reported structure determined by nuclear magnetic resonance (NMR); however, the crystal structure was quite different from the solution structure in both the secondary structural region and the ligand-binding pocket. Molecular modeling based on NMR and X-ray crystallographic data yielded detailed information about the Dvl1/CXXC5 interaction, which will be useful for designing inhibitors.

Physical inactivity and cognitive impairment in Korean older adults: gender differences in potential covariates.

BACKGROUND: Physical inactivity is one major lifestyle risk factor of mild cognitive impairment with ageing. AIM: To investigate whether or not potential covariates modulate the association between physical activity (PA) and cognitive impairment in older adults. SUBJECTS AND METHODS: Data from 10 245 Korean older adults (5817 women) were used. RESULTS: High PA older adults were younger and longer educated and had lower comorbidity and depression than low PA older adults. Compared with low PA men, moderate PA men only had a significantly lower odds-ratio (OR) and 95% confidence interval (95% CI) (OR = 0.795, 95% CI = 0.654 ∼ 0.965, p = 0.021) for having cognitive impairment, even after adjusting for measured covariates, which was no longer significant when additionally adjusted for comorbidity (OR = 0.862, 95% CI = 0.707 ∼ 1.051, p = 0.143). Compared with low PA women, moderate and high PA women had significantly lower risks of cognitive impairment (OR = 0.830, 95% CI = 0.712 ∼ 0.969, p = 0.018 and OR = 0.784, 95% CI = 0.651 ∼ 0.943, p = 0.010, respectively), even after adjusting for the measured covariates including comorbidity, which was no longer significant when additionally adjusted for depression (OR = 0.897, 95% CI = 0.776 ∼ 1.049, p = 0.173 and OR = 0.919, 95% CI = 0.761 ∼ 1.111, p = 0.385, respectively). CONCLUSION: These findings suggest that gender differences in the covariates modulate the relationship between physical activity and cognitive decline in older Korean adults.

Body Fat and Physical Activity Modulate the Association Between Sarcopenia and Osteoporosis in Elderly Korean Women.

This study examined whether modifiable lifestyle factors, such as body fatness and physical activity, modulate the association between sarcopenia and osteoporosis. In a cross-sectional design, 269 postmenopausal women, aged 65 years and older, underwent dual-energy X-ray absorptiometry (DEXA) scans to measure their body fat percentage, total fat mass, total fat-free mass, appendicular lean mass, bone mineral density (BMD) and bone mineral content. The participants wore a uniaxial accelerometer for seven consecutive days to quantify daily physical activity. The collected data were analyzed using descriptive statistics, Pearson correlation, and a binary logistic regression. Pearson correlation analyses showed that total neck/femur BMD was positively associated with weight-adjusted appendicular skeletal muscle mass (ASM) and objectively-measured physical activities. ASM was positively associated with body fatness. Binary logistic regression analyses showed that the odds ratio (OR) of sarcopenia for osteopenia and/or osteoporosis was substantially attenuated but remained marginally significant when adjusted for age and postmenopausal period (OR = 2.370 and p = 0.050). However, the OR was no longer significant when additionally adjusted for body fatness (OR = 2.218 and p = 0.117) and physical activity (OR = 1.240 and p = 0.448). The findings of the study showed that, in this sample of elderly Korean women, modifiable lifestyle risk factors such as body fatness and physical inactivity played an important role in determining the association between sarcopenia and osteopenia/osteoporosis.

Crystal structure of syndesmos and its interaction with Syndecan-4 proteoglycan.

Syndesmos, nucleoside diphosphate linked moiety X (nudix)-type motif 16-like 1 (Nudt16l1), is evolutionarily divergent from the Nudt16 family. Syndesmos, which is co-localized with syndecan-4 cytoplasmic domain (Syn4(cyto)) in focal contacts, interacts with various cell adhesion adaptor proteins to control cell signaling. We determined the X-ray crystal structure of syndesmos; it is composed of seven α-helices and seven ß-strands. Although syndesmos has a molecular topology similar to that of nudix hydrolase proteins, the structure of the nudix motif differs from that of X29. The dimeric interface of syndesmos is composed of α-helix 4, 7 and ß-strand 2, 7, which primarily form hydrophobic interactions. The binding interaction between syndesmos and syn4(cyto) was characterized as a low-affinity interaction (Kd = 62 µM) by surface plasmon resonance (SPR) and nuclear magnetic resonance (NMR). The NMR resonances of Lys (177, 178, 179), Gly182, and Ser183 in the C1 region and Lys193 and Lys194 in the V region of syndecan-4 are perturbed upon syndesmos binding. Our results provide structural insight into the molecular function of syndesmos in the regulation of cell signaling via binding to syndecan-4.