Experimental Limits on Solar Reflected Dark Matter with a New Approach on Accelerated-Dark-Matter-Electron Analysis in Semiconductors

Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM-electron interaction is presented with the 205.4  kg·day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5-15  keV/c^{2}, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1  MeV/c^{2} is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM-electron analyses with semiconductor detectors.

The Lifetime of Hydroxyl Radical in Realistic Fuel Cell Catalyst Layer

The lifetime of hydroxyl radicals (⋅OH) in the fuel cell catalyst layer remains uncertain, which hampers the comprehension of radical-induced degradation mechanisms and the development of longevity strategies for proton-exchange membrane fuel cells (PEMFCs). In this study, we have precisely determined that the lifetime of ⋅OH radicals can extend up to several seconds in realistic fuel cell catalyst layers. This finding reveals that ⋅OH radicals are capable of carrying out long-range attacks spanning at least a few centimeters during PEMFCs operation. Such insights hold great potential for enhancing our understanding of radical-mediated fuel cell degradation processes and promoting the development of durable fuel cell devices.

Hydrogen Spillover Accelerates Electrocatalytic Semi-hydrogenation of Acetylene in Membrane Electrode Assembly Reactor

Electrocatalytic acetylene semi-hydrogenation (EASH) offers a promising and environmentally friendly pathway for the production of C2H4, a widely used petrochemical feedstock. While the economic feasibility of this route has been demonstrated in three-electrode systems, its viability in practical device remains unverified. In this study, we designed a highly efficient electrocatalyst based on a PdCu alloy system utilizing the hydrogen spillover mechanism. The catalyst achieved an operational current density of 600 mA cm-2 in a zero-gap membrane electrode assembly (MEA) reactor, with the C2H4 selectivity exceeding 85%. This data confirms the economic feasibility of EASH in real-world applications. Furthermore, through in situ Raman spectroscopy and theoretical calculations, we elucidated the catalytic mechanism involving interfacial hydrogen spillover. Our findings underscore the economic viability and potential of EASH as a greener and scalable approach for C2H4 production, thus advancing the field of electrocatalysis in sustainable chemical synthesis.

[Changes of uterine morphology and endometrial T2 signal intensity in the fibrotic repair secondary to endometrial injury]

Objective: To investigate the value of uterine morphological parameters and endometrial T2 signal intensity (T2-SI) in evaluating the degree of the fibrotic repair secondary to endometrial injury. Methods: From Sep. 2018 to Feb. 2023, this study prospectively enrolled 29 patients with fibrotic repair secondary to severe endometrial injury (severe group), 17 patients with fibrotic repair secondary to mild to moderate endometrial injury (mild to moderate group), and 40 healthy women of reproductive age (control group) in Nanjing Drum Tower Hospital. The length of uterine cavity (LUC), length of cervix and isthmus (LCI), width of upper uterine cavity (WUUC) and width of lower uterine cavity (WLUC) were measured using magnetic resonance imaging. T2-SI of endometrium and subcutaneous fat of buttocks were measured, and endometrial normalized T2-SI (nT2-SI; T2-SI of endometrium/T2-SI of subcutaneous fat of buttocks) was calculated. Statistical analyses of data were performed using one-way analysis of variance, Mann-Whitney U test, intraclass correlation coefficient, Spearman rho test, area under the receiver operating characteristic curve (AUC). Results: LUC, WUUC, WLUC and endometrial nT2-SI of severe group [(19.7±3.5) mm, (26.9±6.4) mm, (7.9±1.4) mm, 0.73±0.11, respectively] were significantly lower than those of the control group (all P<0.01), while LCI and WUUC/LUC [(51.3±7.3) mm and 1.38±0.34] were significantly higher than those of the control group (all P<0.001). LUC and WLUC of severe group were significantly lower than those of mild to moderate group [(32.4±5.1) mm and (8.8±1.2) mm; all P<0.05], while LCI and WUUC/LUC were significantly higher than those of mild to moderate group [(41.8±8.6) mm and 0.94±0.16; all P<0.001]. LUC and endometrial nT2-SI of mild to moderate group were significantly lower than those of the control group [ (32.4±5.1) vs (35.3±3.5) mm, 0.68±0.13 vs 0.80±0.12; all P<0.01]. LUC, WUUC, WLUC and endometrial nT2-SI were significantly negatively correlated to the degree of the fibrotic repair secondary to endometrial injury (Spearman rho:-0.794, -0.441, -0.471 and -0.316, respectively; all P<0.05), while LCI and WUUC/LUC were significantly positively correlated to the degree of the fibrotic repair secondary to endometrial injury (Spearman rho: 0.481 and 0.674, respectively; all P<0.05). LUC and WUUC/LUC showed high value in distinguishing severe group from the control group or mild to moderate group (all AUC>0.9, all P<0.001). Conclusion: As noninvasive and quantitative biomarkers, uterine morphological parameters and endometrial nT2-SI could evaluate the degree of the fibrotic repair secondary to endometrial injury.

[Clinical and molecular biological characterization of patients with accelerated chronic lymphocytic leukemia]

Objective: To investigate the clinical and molecular biological characteristics of patients with accelerated chronic lymphocytic leukemia (aCLL) . Methods: From January 2020 to October 2022, the data of 13 patients diagnosed with aCLL at The First Affiliated Hospital of Nanjing Medical University were retrospectively analyzed to explore the clinical and molecular biological characteristics of aCLL. Results: The median age of the patients was 54 (35-72) years. Prior to aCLL, five patients received no treatment for CLL/small lymphocytic lymphoma (SLL), while the other patients received treatment, predominantly with BTK inhibitors. The patients were diagnosed with aCLL through pathological confirmation upon disease progression. Six patients exhibited bulky disease (lesions with a maximum diameter ≥5 cm). Positron emission tomography (PET) -computed tomography (CT) images revealed metabolic heterogeneity, both between and within lesions, and the median maximum standardized uptake value (SUVmax) of the lesion with the most elevated metabolic activity was 6.96 (2.51-11.90). Patients with unmutated IGHV CLL accounted for 76.9% (10/13), and the most frequent genetic and molecular aberrations included +12 [3/7 (42.9% ) ], ATM mutation [6/12 (50% ) ], and NOTCH1 mutation [6/12 (50% ) ]. Twelve patients received subsequent treatment. The overall response rate was 91.7%, and the complete response rate was 58.3%. Five patients experienced disease progression, among which two patients developed Richter transformation. Patients with aCLL with KRAS mutation had worse progression-free survival (7.0 month vs 26.3 months, P=0.015) . Conclusion: Patients with aCLL exhibited a clinically aggressive course, often accompanied by unfavorable prognostic factors, including unmutated IGHV, +12, ATM mutation, and NOTCH1 mutation. Patients with CLL/SLL with clinical suspicion of disease progression, especially those with bulky disease and PET-CT SUVmax ≥5, should undergo biopsy at the site of highest metabolic uptake to establish a definitive pathological diagnosis.

Selective Conversion of Propane by Electrothermal Catalysis in Proton Exchange Membrane Fuel Cell

Electrochemical conversion of alkanes to high value-added oxygenated products under a mild condition is of significance. Herein, we effectively couple the electrocatalysis of H2 O2 with the thermo-catalysis of propane oxidation in the cathode of proton exchange membrane fuel cell. Specifically, H2 O2 is in-situ generated on the nitric acid-treated carbon black (C-acid) via 2e- process of oxygen reduction reaction, and then transports to the Fe active sites of MIL-53 (Al, Fe) metal-organic frameworks for propane oxidation. Based on this strategy, the space-time yield of C3 oxygenated products of propane oxidation reaches 2.65 μmol h-1  cm-2 , which represents a new benchmark for electrochemical alkane oxidation in the fuel-cell-type electrolyzer. This study highlights the importance of multifunctional composite catalysts in the field of electrosynthesis.

Mechanism of Particle-Mediated Inhibition of Demetalation for Single-Atom Catalytic Sites in Acidic Electrochemical Environments

Demetalation, caused by the electrochemical dissolution of metal atoms, poses a significant challenge to the practical application of single-atom catalytic sites (SACSs) in proton exchange membrane-based energy technologies. One promising approach to inhibit SACS demetalation is the use of metallic particles to interact with SACSs. However, the mechanism underlying this stabilization remains unclear. In this study, we propose and validate a unified mechanism by which metal particles can inhibit the demetalation of Fe SACSs. Metal particles act as electron donors, decreasing the Fe oxidation state by increasing the electron density at the FeN₄ position, thereby strengthening the Fe-N bond, and inhibiting electrochemical Fe dissolution. Different types, forms, and contents of metal particles increase the Fe-N bond strength to varying extents. A linear correlation between the Fe oxidation state, Fe-N bond strength, and electrochemical Fe dissolution amount supports this mechanism. Our screening of a particle-assisted Fe SACS led to a 78% reduction in Fe dissolution, enabling continuous operation for up to 430 h in a fuel cell. These findings contribute to the development of stable SACSs for energy applications.

[The relationship between Zhu Kerou and the publication Medical History in the Past and Present]

Medical History in the Past and Present (Gu Jin Yi Shi), written by Wang Honghan, has been valued by historians since its discovery. Its publication was linked to Zhu Kerou but the relationship between the book and Zhu had been unclear for a long time. This paper examined medical books, medical notes, letters and local chronicles and other related materials. It was found that Zhu Kerou, also named Wengang and Yanyu, lived in Wu County, Jiangsu. He had studied under Miao Zunyi, a well-known doctor at that time, as his medical teacher for more than ten years. However, he did not maintain medicine as his career, but made a living with arts. He wrote Notes of Orchid (Di Yi Xiang Bi Ji) and had it published, collated and edited as part of the first seven volumes of Medical History in the Past and Present (Gu Jin Yi Shi). He also contributed to two additional volumes of this book.

Revealing the interfacial water structure on a p-nitrobenzoic acid specifically adsorbed Au(111) surface

The detailed structure of the water layer in the inner Helmholtz plane of a solid/aqueous solution interface is closely related to the electrochemical and catalytic performances of electrode materials. While the applied potential can have a great impact, specifically adsorbed species can also influence the interfacial water structure. With the specific adsorption of p-nitrobenzoic acid on the Au(111) surface, a protruding band above 3600 cm-1 appears in the electrochemical infrared spectra, indicating a distinct interfacial water structure as compared to that on bare metal surfaces, which displays a potential-dependent broad band in the range of 3400-3500 cm-1. Although three possible structures have been guessed for this protruding infrared band, the band assignment and interfacial water structure remain ambiguous in the past two decades. Herein, by combining surface-enhanced infrared absorption spectroscopy and our newly developed quantitative computational method for electrochemical infrared spectra, the protruding infrared band is clearly assigned to the surface-enhanced stretching mode of water molecules hydrogen-bonded to the adsorbed p-nitrobenzoate ions. Water molecules, meanwhile, are hydrogen-bonded with themselves to form chains of five-membered rings. Based on the reaction free energy diagram, we further demonstrate that both hydrogen-bonding interactions and coverages of specifically adsorbed p-nitrobenzoate play an important role in determining the structure of the water layer in the Au(111)/p-nitrobenzoic acid solution interface. Our work sheds light on structural studies of the inner Helmholtz plane under specific adsorptions, which advances the understanding of structure-property relationships in electrochemical and heterogeneous catalytic systems.

Mechanism of Cations Suppressing Proton Diffusion Kinetics for Electrocatalysis

Proton transfer is crucial for electrocatalysis. Accumulating cations at electrochemical interfaces can alter the proton transfer rate and then tune electrocatalytic performance. However, the mechanism for regulating proton transfer remains ambiguous. Here, we quantify the cation effect on proton diffusion in solution by hydrogen evolution on microelectrodes, revealing the rate can be suppressed by more than 10 times. Different from the prevalent opinions that proton transport is slowed down by modified electric field, we found water structure imposes a more evident effect on kinetics. FTIR test and path integral molecular dynamics simulation indicate that proton prefers to wander within the hydration shell of cations rather than to hop rapidly along water wires. Low connectivity of water networks disrupted by cations corrupts the fast-moving path in bulk water. This study highlights the promising way for regulating proton kinetics via a modified water structure.

[The prevalence and risk factors of diabetic peripheral artery disease in Chinese communities]

Objective: To investigate the prevalence and risk factors of diabetic peripheral artery disease (PAD) in patients with type 2 diabetes mellitus (T2DM) managed in primary health care in China. Methods: A total of 2 528 T2DM patients were selected using a two-stage cluster random sampling method based on the baseline survey of the "China Diabetic Foot Prevention Model Project." The study was conducted in 2015 among T2DM patients in 8 primary healthcare centers in Changshu county and Jiang'an district of Wuhan, China. Data collection methods included a questionnaire, body measurement, and blood glucose detection. The Ankle-Brachial Index (ABI) is the most widely used noninvasive vascular test. A binary logistic regression model was used to analyze the influence factors. Results: The prevalence of PAD was 11.2% among the diabetic patients managed in primary health care in the two cities. The prevalence of PAD under 55 years old, 55- years old, 65- years old, and ≥75 years old were 7.8%, 6.0%, 12.9% and 22.5%, respectively. Multivariate stepwise logistic regression identified influence factors included older age, higher education level, smoking, drinking, postprandial glucose uncontrol, and prior myocardial infarction or angina. Compared to age <55 years, the odds ratio for PAD were 0.74 for 55- years (95%CI: 0.43-1.28), 1.72 for 65- years (95%CI: 1.05-2.81), 3.56 for 75 years and above (95%CI: 2.07-6.11), respectively. Compared to patients with education in primary school and below, the odds ratio was 1.37 (95%CI: 0.97-1.94), 2.48 (95%CI: 1.73-3.55), 1.99 (95%CI: 1.26-3.13) for those with education levels of junior high school, senior high school, and college, respectively. Current smoking (OR=1.49, 95%CI: 1.02-2.17), current drinking (OR=0.45, 95%CI: 0.28-0.71), postprandial glucose uncontrol (2 h postprandial plasma glucose >10.0 mmol/L: OR=1.72, 95%CI: 1.22-2.43), and prior myocardial infarction or angina (OR=2.32, 95%CI: 1.50-3.61) were influencing factors of PAD. Conclusions: Despite the high prevalence of PAD in diabetes managed in primary health care; multiple risk factors are not effectively aware of and under control. It is urgent to promote ABI screening and standardized management for diabetes, especially in primary health care.

Constraints on Sub-GeV Dark Matter-Electron Scattering from the CDEX-10 Experiment

We present improved germanium-based constraints on sub-GeV dark matter via dark matter-electron (χ-e) scattering using the 205.4  kg·day dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted χ-e scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for m_{χ} larger than 80  MeV/c^{2} compared to previous germanium-based χ-e results. We also present the most stringent χ-e cross-section limit to date among experiments using solid-state detectors for m_{χ} larger than 90  MeV/c^{2} with heavy mediators and m_{χ} larger than 100  MeV/c^{2} with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new χ-e detection method with high-purity germanium detectors in ultralow radioactive background.

Exotic Dark Matter Search with the CDEX-10 Experiment at China's Jinping Underground Laboratory

A search for exotic dark matter (DM) in the sub-GeV mass range has been conducted using 205 kg day data taken from a p-type point contact germanium detector of the CDEX-10 experiment at China's Jinping underground laboratory. New low-mass dark matter searching channels, neutral current fermionic DM absorption (χ+A→ν+A) and DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), have been analyzed with an energy threshold of 160 eVee. No significant signal was found; thus new limits on the DM-nucleon interaction cross section are set for both models at the sub-GeV DM mass region. A cross section limit for the fermionic DM absorption is set to be 2.5×10^{-46}  cm^{2} (90% C.L.) at DM mass of 10  MeV/c^{2}. For the DM-nucleus 3→2 scattering scenario, limits are extended to DM mass of 5 and 14  MeV/c^{2} for the massless dark photon and bound DM final state, respectively.

Identification of the active triple-phase boundary of a non-Pt catalyst layer in fuel cells

The rational design of non-Pt oxygen reduction reaction (ORR) catalysts and catalyst layers in fuel cells is largely impeded by insufficient knowledge of triple-phase boundaries (TPBs) in the micropore and mesopore ranges. Here, we developed a size-sensitive molecular probe method to resolve the TPB of Fe/N/C catalyst layers in these size ranges. More than 70% of the ORR activity was found to be contributed by the 0.8- to 2.0-nanometer micropores of Fe/N/C catalysts, even at a low micropore area fraction of 29%. Acid-alkaline interactions at the catalyst-polyelectrolyte interface deactivate the active sites in mesopores and macropores, resulting in inactive TPBs, leaving micropores without the interaction as the active TPBs. The concept of active and inactive TPBs provides a previously unidentified design principle for non-Pt catalyst and catalyst layers in fuel cells.

Identification of a pyrone-type species as the active site for the oxygen reduction reaction

A bicyclic pyrone-type species on oxygen-doped carbon catalysts was identified as the active site for the oxygen reduction reaction in acidic solution. It has much higher activity than that of typical nitrogen-doped carbon catalysts (0.219 e s^-1 site^-1vs. 0.021-0.088 e s^-1 site^-1 at 0.6 V_RHE). The ortho-carbon atom in the carbonyl ring of the pyrone-type species was revealed as the reactive site by theoretical calculations.

General Carbon-Supporting Strategy to Boost the Oxygen Reduction Activity of Zeolitic-Imidazolate-Framework-Derived Fe/N/Carbon Catalysts in Proton Exchange Membrane Fuel Cells

The oxygen reduction reaction (ORR) activity of the Fe/N/Carbon catalysts derived from the pyrolysis of zeolitic-imidazolate-framework-8 (ZIF-8) has been still lower than that of commercial Pt-based catalysts utilized in the proton exchange membrane fuel cells (PEMFCs) due to low density of accessible active sites. In this study, an efficient carbon-supporting strategy is developed to enhance the ORR efficiency of the ZIF-derived Fe/N/Carbon catalysts by increasing the accessible active site density. The enhancement lies in (i) improving the accessibility of active sites via converting dodecahedral particles to graphene-like layered materials and (ii) enhancing the density of FeN_x active sites via suppressing the formation of nanoparticles as well as providing extra spaces to host active sites. The optimized and efficient Fe/N/Carbon catalyst shows a half-wave potential (E_1/2) of 0.834 V versus reversible hydrogen electrode in acidic media and produces a peak power density of 0.66 W cm^-2 in an air-fed PEMFC at 2 bar backpressure, outperforming most previously reported Pt-free ORR catalysts. Finally, the general applicability of the carbon-supporting strategy is confirmed using five different commercial carbon blacks. This work provides an effective route to derive Fe/N/Carbon catalysts exhibiting a higher power density in PEMFCs.

[Preconception reproductive health and birth outcome cohort in Chongqing: the cohort profile]

Birth cohort is an important platform to study the effect of early-life exposure on health outcome, but large cohorts to investigate the effect of preconception exposure, especially paternal exposure, on reproductive health and birth outcome are limited. The Preconception Reproductive Health and Birth Outcome Cohort (PREBIC) is a prospective birth cohort study which pays equal attention to the contribution of environmental, psychological, behavioral as well as other factors to reproductive health and adverse birth outcomes in both men and women in Chongqing, China. PREBIC started in 2019 and plans to recruit 20 800 reproductive-age couples with child-bearing willingness. Followed up was conducted to understand the conception status of the women within two years. Women in pregnancy would be visited at first, second, third trimesters and after delivery. The offspring would be monitored until 2 years old to understand the incidences of preterm birth, low birth weight, birth defects, neurodevelopmental disorders and other outcomes. Related information and biospecimen collections (including semen, peripheral blood, urine, placenta, umbilical cord, cord blood and oral swab) were scheduled in each period. By January 2022, PREBIC had recruited 8 698 participants from all 38 districts in Chongqing. The goal of PREBIC is to establish one of the largest prospective preconception birth cohorts covering both men and women, which might provide a unique insight to understand the effects of the full reproductive cycle on reproductive health and adverse outcomes, with especial emphasis on preconception exposures.

High CO-Tolerant Ru-Based Catalysts by Constructing an Oxide Blocking Layer

CO poisoning of Pt-group metal catalysts is a long-standing problem, particularly for hydrogen oxidation reaction in proton exchange membrane fuel cells. Here, we report a catalyst of Ru oxide-coated Ru supported on TiO₂ (Ru@RuO₂/TiO₂), which can tolerate 1-3% CO, enhanced by about 2 orders of magnitude over the classic PtRu/C catalyst, for hydrogen electrooxidation in a rotating disk electrode test. This catalyst can work stably in 1% CO/H₂ for 50 h. About 20% of active sites can survive even in a pure CO environment. The high CO tolerance is not via a traditional bifunctional mechanism, i.e., oxide promoting CO oxidation, but rather via hydrous metal oxide shell blocking CO adsorption. An ab initio molecular dynamics (AIMD) simulation indicates that water confined in grain boundaries of the Ru oxide layer and Ru surface can suppress the diffusion and adsorption of CO. This oxide blocking layer approach opens a promising avenue for the design of high CO-tolerant electrocatalysts for fuel cells.

Quasi-isentropic compression of LiH above 400 GPa using magnetocumulative generator

The knowledge of high-pressure behavior of LiH is significant for the validation of fundamental theoretical models and applications in thermonuclear materials and potential energy supplies. The compressibility of ⁷LiH under isentropic compression at high pressure was investigated experimentally and theoretically. The experimental technique for quasi-isentropic compression with low-density materials was developed using the magnetocumulative generator CJ-100 and x-ray flash radiography. The x-ray images and extracted interface of the sample target in dynamic flash radiography experiments were obtained. According to each interface size of the target both before and after compression, the compression ratio of ⁷LiH and reference material aluminum was obtained. The density of the reference and using its known isentropic curve provide the pressure in the reference. The pressure in ⁷LiH was deduced from the pressure in the reference and using the calculated gradient correction factor. The quasi-isentropic data point at 438 GPa was obtained experimentally. A semiempirical three-term complete equation of state was constructed and validated for ⁷LiH using the theory of Mie-Grüneisen-Debye with experimental data from the literature. The quasi-isentrope data point is reasonably consistent with the theoretical results. The quasi-isentropic experimental techniques and results broaden the existing research scope and are practical and helpful to further validate theoretical models in the future.

Impact of Pore Structure on Two-Electron Oxygen Reduction Reaction in Nitrogen-Doped Carbon Materials: Rotating Ring-Disk Electrode vs. Flow Cell

The impact of pore structure on the two-electron oxygen reduction reaction (ORR) in nitrogen-doped carbon materials is currently under debate, and previous studies are mainly limited to the rotating ring-disk electrode (RRDE) rather than the practical flow cell (FC) system. In this study, assisted by a group of reliable pore models, the impact of two pore structure parameters, that is, Brunauer-Emmett-Teller surface area (S_BET ) and micropore surface fraction (f_micro ), on ORR activity and selectivity are investigated in both RRDE and FC. The ORR mass activity correlates positively to the S_BET in the RRDE and FC because a higher S_BET can host more active sites. The H₂ O₂ selectivity is independent of f_micro in the RRDE but correlates negatively to f_micro in the FC. The inconsistency results from different states of the electrode in the RRDE and the FC. These insights will guide the design of carbon materials for H₂ O₂ synthesis.

Evolution of Cu single atom catalysts to nanoclusters during CO2 reduction to CO

We synthesized Cu single atoms embedded in a N-doped porous carbon catalyst with a high Faradaic efficiency of 93.5% at -0.50 V (vs. RHE) for CO₂ reduction to CO. The evolution of Cu single-atom sites to nanoclusters of about 1 nm was observed after CO₂ reduction at a potential lower than -0.30 V (vs. RHE). The DFT calculation indicates that Cu nanoclusters improve the CO₂ activation and the adsorption of intermediate *COOH, thus exhibiting higher catalytic activity than CuN_x sites. The structural instability observed in this study helps in understanding the actual active sites of Cu single atom catalysts for CO₂ reduction.

Accelerated interfacial proton transfer for promoting the electrocatalytic activity

Interfacial pH is critical to electrocatalytic reactions involving proton-coupled electron transfer (PCET) processes, and maintaining an optimal interfacial pH at the electrochemical interface is required to achieve high activity. However, the interfacial pH varies inevitably during the electrochemical reaction owing to slow proton transfer at the interfacial layer, even in buffer solutions. It is therefore necessary to find an effective and general way to promote proton transfer for regulating the interfacial pH. In this study, we propose that promoting proton transfer at the interfacial layer can be used to regulate the interfacial pH in order to enhance electrocatalytic activity. By adsorbing a bifunctional 4-mercaptopyridine (4MPy) molecule onto the catalyst surface via its thiol group, the pyridyl group can be tethered on the electrochemical interface. The pyridyl group acts as both a good proton acceptor and donor for promoting proton transfer at the interfacial layer. Furthermore, the pK_a of 4MPy can be modulated with the applied potentials to accommodate the large variation of interfacial pH under different current densities. By in situ electrochemical surface-enhanced Raman spectroscopy (in situ EC-SERS), we quantitatively demonstrate that proton transfer at the interfacial layer of the Pt catalyst coated with 4MPy (Pt@4MPy) remains ideally thermoneutral during the H⁺ releasing electrocatalytic oxidation reaction of formic acid (FAOR) at high current densities. Thus, the interfacial pH is controlled effectively. In this way, the FAOR apparent current measured from Pt@4MPy is twice that measured from a pristine Pt catalyst. This work establishes a general strategy for regulating interfacial pH to enhance the electrocatalytic activities.

Adsorbing 4MPy on Pt surface promotes proton transfer at the interfacial layer, maintaining an optimal interfacial pH and promotes electrocatalytic reactions involving proton-coupled electron transfer (PCET) processes.

Recent Advances in Electrocatalysts for Proton Exchange Membrane Fuel Cells and Alkaline Membrane Fuel Cells

The rapid progress of proton exchange membrane fuel cells (PEMFCs) and alkaline exchange membrane fuel cells (AMFCs) has boosted the hydrogen economy concept via diverse energy applications in the past decades. For a holistic understanding of the development status of PEMFCs and AMFCs, recent advancements in electrocatalyst design and catalyst layer optimization, along with cell performance in terms of activity and durability in PEMFCs and AMFCs, are summarized here. The activity, stability, and fuel cell performance of different types of electrocatalysts for both oxygen reduction reaction and hydrogen oxidation reaction are discussed and compared. Research directions on the further development of active, stable, and low-cost electrocatalysts to meet the ultimate commercialization of PEMFCs and AMFCs are also discussed.

[The cervical microbiota characteristics in patients with human papillomavirus infection]

Objective: To investigate the characteristics of cervical microbiota in patients with HPV (Human Papillomavirus) infection, and to analyze the associations of cervical microbiota and HPV infection or cervicitis. Methods: 300 samples underwent HPV nucleic acid testing was collected in this case-control study from June 2019 to April 2020 in the Zhujiang Hospital of Southern Medical University, there were 150 cases allocated in HPV infection group (HPV+), and 150 cases of negative nucleic acid test were non-infectious Group (HPV-). Next-generation sequencing was used to sequence the V4 region of the bacterial 16S rRNA gene, and QIIME pipeline was used to analysis the microbiota composition of the two groups. Wilcoxon rank sum test and Kruskal-Wallis test were used to statistically analysis the differences of the microbiota between groups; and the α diversity and β diversity of the flora between groups were statistically analyzed by Adonis multivariate analysis of variance and Wilcoxon rank sum test. Results: A total of 300 samples were analyzed in this study, of which 150 samples were HPV-positive and 150 samples were HPV-negative; among HPV-positive cases, 132 were infected by high-risk HPV (88.0%), and 18 were low-risk HPV infections (12.0%). The composition of the cervical microbiota were significantly different between the HPV+group and the HPV-group, which in the HPV+group, the α diversity of the cervical microbiota were significantly increased (Shannon index, W=8 174, P<0.000 1; PD whole tree, W=8 887, P=0.001 7). The β diversity of the two groups was significantly different (Binary Jaccard, F=2.325 4, P=0.042 0; Bray Curtis, F=2.136 44, P=0.044 0). The relative abundance of Lactobacillus spp. and L.iners in the HPV+group sample decreased significantly (W=7 730, P<0.000 1; W=8 979, P=0.002 5), accompanied by enriched Achromobacter, Stenotrophomonas, Methylobacterium, Sneathia and Dialister. There was no significant difference in the composition of the cervical microbiota between high-risk HPV infection and low-risk HPV infection (F=4.100 4, P>0.05). In addition, cervicitis is significantly related to HPV infection (χ²=19.78, P<0.000 1), the composition of cervical flora has similarity features in cervicitis and HPV infection samples. Compared with the normal group, the cervical microbiota of cervicitis with HPV infection is mainly enriched in Achromobacter, Aerococcaceae, Streptococcus, Fusobacteria, and Xanthomonadaceae. Conclusion: The cervical microbiota of patients with HPV infection has a significant dysbiosis, with increased diversity and significant depletion of lactobacillus, accompanied by an increase in the abundance of pathogenic bacteria such as Achromobacter.

[Grading of tumor budding in intestinal-type early gastric adenocarcinoma and its role in assessing the risk of lymph node metastasis]

Objective: To investigate the role of tumor budding (TB) in predicting lymph node metastasis of intestinal-type early gastric adenocarcinoma, and to determine the optimal cutoff value of TB number. Methods: A total of 202 patients with intestinal-type early gastric adenocarcinoma, who underwent surgical operation at the Affiliated Wuxi People's Hospital of Nanjing Medical University, Jiangsu, China from 2008 to 2018 were included. According to the International Tumor Budding Consensus Conference (ITBCC) criteria, the number of TB for each case was assessed. The receiver operating characteristic (ROC) curve was employed to determine the optimal cutoff value of TB number for predicting lymph node metastasis, and multivariate logistic regression was used to analyze whether a high TB number was an independent risk factor for lymph node metastasis. In addition, in the patients, who met the indications for endoscopic resection and developed lymph node metastasis, the association of a high number of TB with lymph node metastasis was examined. Results: TBs were observed in 63.4% (128/202) of intestinal-type early gastric adenocarcinomas. Using ROC curve, 4 TBs was found as the optimal cutoff value to predict lymph node metastasis (area under the curve 0.767; sensitivity 0.657; specificity 0.780). Therefore, the 202 cases were divided into two groups: the high-budding (≥4 TBs) group (n=60) and the low-budding (<4 TBs) group (n=142). The high-budding group exhibited a higher rate of lymph node metastasis than that of the low-budding group (41.7% vs 9.1%, P<0.01), and ≥4 TBs was associated with deeper invasion and lymph vessel invasion (P<0.01). The multivariate regression model showed that ≥4 TBs was an independent risk factor for lymph node metastasis (Hazard ratio=8.760, 95%CI 2.648-28.987; P<0.01). Meanwhile, 4 TBs as the cutoff value could better predict lymph node metastasis than the cutoff value advised by the ITBCC. In addition, 3 cases were found to have developed lymph node metastasis even that they met the expanded indications for endoscopic resection, and 2 of these 3 cases exhibited a higher TB number (≥4 TBs). Conclusions: More than 4 TBs are a useful indicator for predicting lymph node metastasis in intestinal-type early gastric adenocarcinoma. It may be used to as an endoscopic resection criterion for patients with a high risk of lymph node metastasis.

[The gender disparity and relevant factors of frailty in the elderly of communities in Beijing based on Fairlie decomposition analysis]

Objective: To analyze the gender disparity and relevant factors of frailty in the elderly of communities in Beijing. Methods: From November 2015 to January 2016, 1 557 participants aged 60 and older in four communities of Dongcheng district in Beijing were recruited by cluster sampling. The information of demographic characteristics, social support, economic status, health status, prevalence situation, cognitive function, emotion and comprehensive assessment of the elderly were collected by a self-made questionnaire. The frailty index (FI) model was used to evaluate the frailty of the elderly. Multivariate nonconditional logistic regression model and Fairlie decomposition method were applied to analyze the relevant factors and their contribution rate to the difference between males and females. Results: The age of subjects was (74.5±8.5) years old, ranging from 60-102 years old, among which 641 were males, accounting for 41.2%. The M (Q₁, Q₃) of FI was 0.09 (0.06, 0.14), among which the value in males was 0.08 (0.05, 0.13), lower than females [0.10 (0.06, 0.15)] (P<0.001).The frail proportion in female was 14.9% (137/916), higher than that of male [8.4% (54/641)] (P<0.001). Multivariate nonconditional logistic regression model analysis demonstrated that common relevant factors associated with frailty in older women and men include: age ≥80 years old, marital status as not married (unmarried, separated, divorced, or widowed), living alone increased the risk of frailty; participating in group activities ≥3 times/week and exercising regularly decreased the risk of frailty (all P<0.05). Fairlie decomposition method showed that the contribution rate of life style, family support, marital status and social support were 32.21%, 15.26%, 8.23% and 4.34%, respectively (all P<0.05). Conclusions: The frailty degree and frailty proportion of elderly women in communities in Beijing were higher than those of men of the same age. The frailty gender difference was related to lifestyle, family support, marital status and social support.

Shape transformations of Pt nanocrystals enclosed with high-index facets and low-index facets

Shape transformation between high-index faceted Pt nanocrystals and low-index faceted ones have been achieved by an electrochemical square-wave potential method.

[Efficacy and safety of pylorus-preserving gastrectomy for early gastric cancer located in the middle third of the stomach: a meta-analysis]

Objective: It is yet to be clarified whether pylorus-preserving gastrectomy (PPG) for early gastric cancer will bring the risk of radical tumor resection, whether it will increase the incidence of postoperative complications, and how much is the benefit of the quality of life for patients after surgery, these issues are not clear. This meta-analysis aims to evaluate the efficacy and safety of pylorus-preserving gastrectomy (PPG) for early middle gastric cancer. Methods: The Chinese and English literatures about PPG and distal gastrectomy (DG) for early gastric cancer were searched from PubMed, Embase, The Cochrane Library, Web of Science, CNKI net and Wanfang database. Literature inclusion criteria: (1) Prospective or retrospective cohort study of PPG and DG for early middle-third gastric cancer published publicly; (2) Patients with early middle-third gastric cancer; (3) The enrolled literatures include at least one of the following outcome indicators: the efficacy indicators include gallstone, residual gastritis, bile reflux, delayed gastric emptying, dumping syndrome, reflux esophagitis and overall complication; the long-term prognostic indicators include 5-year survival rate and 5-year tumor recurrence. Literature exclusion criteria: (1) Reviews, case reports, conference summaries and other non-control studies; (2) Repeated published studies, incomplete studies and unextractable studies; (3) The depth of tumor invasion exceeding submucosa. The search time ended in July 2020. The basic information and evaluation indicators included in the article were extracted. The retrospective study was evaluated using Newcastle-Ottawa literature quality evaluation scale. The prospective randomized controlled study was evaluated using Jadad modified scale. Meta-analysis was performed using Review Manager 5.3. Publication bias was assessed using funnel map. Publication bias was tested using Egger tools. Results: A total of 717 literatures were retrieved, and 17 literatures were enrolled finally, including 2 randomized controlled trials and 15 retrospective studies. A total of 2427 patients were enrolled, including 948 in PPG group and 1479 in DG group. The meta-analysis of the efficacy indicators showed that there were significant differences in gallstones incidence (OR=0.42, 95% CI: 0.28-0.65, P<0.001), residual gastritis incidence (OR=0.50, 95% CI: 0.32-0.77,P=0.002), bile reflux incidence (OR=0.30, 95% CI: 0.20-0.45, P<0.001), delayed gastric emptying incidence (OR=2.40, 95% CI:1.67-3.45, P<0.001), and postoperative dumping syndrome incidence (OR=0.28, 95% CI: 0.15-0.51, P<0.001), while there were no significant differences in postoperative overall complications (OR=0.97, 95% CI: 0.69-1.35, P=0.840), reflux esophagitis incidence (OR=0.79, 95% CI: 0.39-1.61, P=0.520) between the two groups. The meta-analysis of the long-term prognostic indicators showed that no significant differences of 5-year survival (OR=1.02, 95% CI: 0.61-1.71, P=0.940) or 5-year tumor recurrence (OR=0.77, 95% CI: 0.36-1.68, P=0.520) were observed between the two groups. Conclusion: The incidences of gallstone, residual gastritis, dumping syndrome, bile reflux are lower after PPG in early gastric cancer, while the postoperative overall complications and long-term survival are comparable between PPG and DG, indicating that PPG is quite safe and feasible.

Early Follow-Up of Arthroscopic Latarjet Procedure with Screw or Suture-Button Fixation for Recurrent Anterior Shoulder Instability

Objective

To evaluate the early clinical and radiographic results of arthroscopic Latarjet procedure using screw or suture‐button fixation in patients with recurrent anterior shoulder dislocation.

Methods

Twelve patients who underwent arthroscopic Latarjet procedure between January 2015 and December 2018 at our institution were retrospectively studied. Data of the patients' history, including age, gender, side of affected arm, body mass index (BMI), and the number of dislocations since fist dislocation were collected. Preoperative and postoperative clinical follow‐up data were evaluated using Walch–Duplay score, American Shoulder and Elbow Society (ASES) score, and modified Rowe score. Active external rotation and active internal rotation at 90° of abduction as well as active elevation were evaluated preoperatively and postoperatively. The position and healing condition of the transferred coracoid bony graft were also assessed using computed tomography (CT) and Mimics 19.0 software.

Results

Mean follow‐up was 24.9 months (range, 13 to 53 months) of all patients. At final follow‐up, the average ASES score (preoperative vs postoperative values) had improved from 68.9 ± 7.9 to 91.1 ± 6.1 in screw fixation group and 68.9 ± 8.9 to 87.5 ± 6.7 in suture‐button fixation group; the average Rowe score (preoperative vs postoperative values) had improved from 25.0 ± 8.4 to 92.5 ± 4.2 in screw fixation group and 21.7 ± 13.7 to 93.3 ± 4.1 in suture‐button fixation group; the average of Walch–Duplay score (preoperative vs postoperative values) had improved from 12.5 ± 15.1 to 91.7 ± 4.1 in screw fixation group and 18.3 ± 20.7 to 88.3 ± 7.5 in button fixation group. The forward flexion was 175.0° ± 8.4° preoperatively and 178.3° ± 4.1° postoperatively in screw fixation group while 174.8° ± 10.2° preoperatively and 175.0° ± 5.5° postoperatively in suture‐button fixation group. The active external rotation was 77.5° ± 5.2° preoperatively and 71.7° ± 4.1° postoperatively in screw fixation group while 72.5° ± 6.9° preoperatively and 68.3° ± 7.5° postoperatively in suture‐button fixation group. The average of active internal rotation was 66.7° ± 6.1° preoperatively and 67.5° ± 6.1° postoperatively in screw fixation group while 68.3° ± 11.3° preoperatively and 66.7° ± 7.5° postoperatively in suture‐button fixation group. In postoperative CT scan, 91.7% grafts midline center were located at or under the equator in the en face view; 75% of the bone blocks were flush to the glenoid face in the axial view, with only two grafts exhibiting slight medial placement in screw fixation group (33.3%) and one graft exhibiting slight lateral placement in suture‐button fixation group (16.7%). All grafts achieved bone union. Graft absorption mostly occurred outside of the “best‐fit” circle. The average bony absorption rates of the coracoid grafts were 25.2% and 10.18% in screw fixation group and suture‐button fixation group, respectively, at 6 months postoperative follow‐up.

Conclusion

Both suture‐button fixation and screw fixation techniques in arthroscopic Latarjet procedure revealed excellent clinical outcomes with low complication rates in the early follow‐up. The suture‐button fixation exhibited a flexible fixation pattern that allowed for self‐correction to some extent, even slight lateralization could finally remodel over time.

[Relationship between frailty status and risk of death in the elderly based on frailty index analysis]

Objective: To analyze the relationship between frailty status and the risk of death in the elderly based on the frailty index (FI). Methods: Data from a prospective cohort study conducted between 2005 and 2015 in elderly people of an urban community in Beijing were analyzed. The variables related to health and frailty status based on the 2005 baseline survey and death as outcome variables collected in 2015 were used. A FI model was used to evaluate the correlation between FI and mortality in the elderly people in different age groups was analyzed. Cox regression was applied to evaluate the influence of FI on the risk of death, and Kaplan-Meier curves was used to show the survival rate of different frailty levels in the elderly adults. Results: Of the 1 301 elderly people included in the analysis, 403 died during 2005-2015, with the 10-year mortality rate of 31.0%(403/1 301). The mortality rate of the elderly increased with the increase of FI, but, with the increase of FI value, the rate of mortality increased slowly. The limit value of FI causing death was around 0.70, indicating any new health problem might cause death at this value. Cox regression analysis showed that higher FI was associated with higher risk for death (HR=1.143, 95%CI: 1.034-1.248, P=0.000), and FI was more significantly associated with death than age (HR=1.143 vs. HR=1.048, t=5.827, P=0.000). With the increase of age, the effect of frailty on the risk of death decreased (HR=1.179 to HR=1.120). Kaplan-Meier curves showed that the survival rate of the elderly in all age groups decreased with the increase of frailty (Log-rank=317.812, 354.203, 247.258, all P=0.000). The survival time between different frailty levels in the elderly were significantly different, except for the elderly adults aged ≥80 years with severe frailty level (0.4≤FI<0.5, FI≥0.5, P=0.368). Conclusions: Compared with other evaluation tools of frailty, FI model can better reflect the frailty status of the elderly in communities in Beijing and has a high sensitivity in predicting adverse outcomes such as mortality. In the intervention of frailty in the elderly, focusing on relatively young elderly might be more effective in reducing the adverse outcomes caused by frailty.

[Risk assessment of occupational noise exposure in an automobile parts manufacturing enterprise]

Objective: To investigate the risk of occupational hearing loss caused by noise exposure in an automobile parts manufacturing enterprise. Methods: In June 2019, an automobile parts manufacturing enterprise in Huizhou City was selected to conduct occupational hygiene field investigation, and occupational health investigation and occupational hazards detection were carried out in the workplace. 395 workers with 8-hour working day equivalent sound level (L(ex·8 h)) ≥85 dB (a) were selected as the research objects. The occupational noise exposure risk assessment method was used to assess the noise exposure risk of L(ex·8 h)≥85 dB (a) , and the risk of high-frequency hearing loss and occupational noise deafness caused by noise exposure were evaluated when the working years were 10, 20, 30, 35 and 40. Results: When the exposure years were less than or equal to 30 years, the risk of high-frequency hearing loss of bearing pedestal final examiners was medium risk, and the risk of other positions was acceptable; the highest risk of noise deafness was the bearing pedestal final examiner, and the risk classification was higher, and the other types of work were negligible risk and acceptable risk. When the exposure years are more than 30 years, the risk classification of high-frequency hearing loss of bearing pedestal final inspection workers is high-risk, and the risk classification of other types of work is medium risk; the highest risk of noise deafness is the bearing pedestal final inspection workers, and the risk classification is higher risk, and the other types of work are medium risk. Conclusion: The enterprise should pay attention to the risk of occupational hearing loss caused by noise exposure, especially the bearing pedestal final inspection workers, and strengthen the hearing protection of noise exposed people.

Acetone, butanol, and ethanol production from puerariae slag hydrolysate through ultrasound-assisted dilute acid by Clostridium beijerinckii YBS3

In this study, puerariae slag (PS) was evaluated as a renewable raw material for acetone-butanol-ethanol (ABE) fermentation. To accelerate the hydrolysis of PS, the method of ultrasound-assisted dilute acid hydrolysis (UAAH) was used. With this effort, 0.69 g reducing sugar was obtained from 1 g raw material under the optimal pretreatment condition. Subsequently, the butanol and total solvent production of 8.79 ± 0.16 g/L and 12.32 ± 0.26 g/L were obtained from the non-detoxified diluted hydrolysate, and the yield and productivity of butanol were 0.19 g/g and 0.12 g/L/h, respectively. Additionally, the changes in the structure of PS after different pretreatment methods were observed using SEM and FT-IR. UAAH resulted in more severe and distinct damage to the dense structure of PS. This study suggests that the UAAH is an attainable but effective pretreatment method, thereby is a promising technique for lignocellulose hydrolysis and improve butanol production.

Porous Carbon Membrane-Supported Atomically Dispersed Pyrrole-Type FeN4 as Active Sites for Electrochemical Hydrazine Oxidation Reaction

The rational design of catalytically active sites in porous materials is essential in electrocatalysis. Herein, atomically dispersed Fe-N_x sites supported by hierarchically porous carbon membranes are designed to electrocatalyze the hydrazine oxidation reaction (HzOR), one of the key techniques in electrochemical nitrogen transformation. The high intrinsic catalytic activity of the Fe-N_x single-atom catalyst together with the uniquely mixed micro-/macroporous membrane support positions such an electrode among the best-known heteroatom-based carbon anodes for hydrazine fuel cells. Combined with advanced characterization techniques, electrochemical probe experiments, and density functional theory calculation, the pyrrole-type FeN₄ structure is identified as the real catalytic site in HzOR.

Hierarchically Porous Carbons Derived from Nonporous Coordination Polymers

Hierarchically porous carbons (HPCs) with multimodal pore systems exhibit great technological potentials, especially in the fields of heterogeneous catalysis, energy storage, and conversion. Here, we establish a simple and general approach to HPCs by carbonization of nonporous coordination polymers that are produced by mixing metal salts with polytopic ligands in alkaline aqueous solutions at room temperature. The proposed approach is applicable to a wide scope of ligand molecules (18 examples), thus affording the synthesized HPCs with high diversity in porosity, morphology, and composition. In particular, the prepared HPCs exhibit high specific surface areas (up to 2647 m² g^-1) and large pore volumes (up to 2.39 cm³ g^-1). The HPCs-supported atomically dispersed Fe-N_x catalysts show much-improved fuel cell cathode performance over the micropore-dominated carbon black-supported catalysts, demonstrating the structural superiority of the HPCs for enhancing the mass transport properties.

Direct Detection Constraints on Dark Photons with the CDEX-10 Experiment at the China Jinping Underground Laboratory

We report constraints on the dark photon effective kinetic mixing parameter (κ) with data taken from two p-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90% confidence level upper limits on κ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (m_{V}) from 10 to 300  eV/c^{2} in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90% confidence level with m_{V} from 0.1 to 4.0  keV/c^{2} are set from 449.6 kg-day data, with a minimum of κ=1.3×10^{-15} at m_{V}=200  eV/c^{2}.

[Prevalence and risk factors of diabetic peripheral neuropathy in Chinese communities]

Objective: To investigate the prevalence and risk factors of diabetic peripheral neuropathy in type 2 diabetic patients under community management programs. Methods: A cross-sectional study was conducted on T2DM patients in eight communities in Wuhan and Changshu cities. Data would included questionnaire, body measurement, blood testing and clinical examination. The criterion of diabetic peripheral neuropathy was under the combination of symptoms with five physical examinations. Binary logistic regression model was used to analyze the influential factors. Results: The overall prevalence of peripheral neuropathy was 71.2% among the diabetic patients who were managed in primary care health services in the two cities. The binary logistic regression method identified older age (≥60 years, OR=2.39, 95%CI:1.95-2.94), longer diabetic duration (≥10 years, OR=1.25, 95%CI: 1.02-1.54), and worse postprandial glucose control (2 h postprandial plasma glucose >10.0 mmol/L: OR=1.65, 95%CI:1.33-2.04) (all P<0.05) as risk factors for the presence of diabetic peripheral neuropathy, while higher education level was protective factor (compared to patients with education levels of primary school or below, OR=0.52, 95%CI: 0.41-0.66; OR=0.59, 95%CI: 0.44-0.79; OR=0.64, 95%CI: 0.44-0.94 for those with education levels of junior high school, senior high school, and college, respectively). Conclusions: High rates of diabetic peripheral neuropathy among T2DM patients suggested the urgent need for early screening and standardized management at the community levels. It is necessary to promote appropriate screening techniques and methods to identify the peripheral neuropathy, in the primary health service institutions.

Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory

We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2-yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (χ-N) spin-independent cross sections as function of WIMP mass (m_{χ}) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at >99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at m_{χ}<6  GeV/c^{2} among WIMP AM measurements to date.

Electrochemical CO2 reduction on Cu and Au electrodes studied using in situ sum frequency generation spectroscopy

As an important pathway for energy storage and a key reaction in the carbon cycle, the CO₂ electrochemical reduction reaction has recently gained significant interest. A variety of catalysts have been used to approach this topic experimentally and theoretically; however, the molecular level insight into the reaction mechanism is lacking due to the complexity of the surface processes and the challenges in probing the intermediate species. In this study, CO₂ reduction reactions on polycrystalline Cu and Au electrodes were investigated in 0.1 M CO₂-saturated NaHCO₃ solution. In situ sum frequency generation (SFG) spectroscopy has been adopted to access the intermediates and products on the metal electrodes. On the Au electrode, only linearly adsorbed CO could be detected, and the reduction produced no hydrocarbon species. On the Cu electrode, C-H stretching vibrations corresponding to surface-adsorbed ethoxy species were observed, but no CO vibrations can be detected with SFG. The results revealed that the CO randomly adsorbed on the Cu surface, and the multiple orientations of the adsorbed species may be the reason for the formation of C-C bonding. These results demonstrate direct molecular level evidence for different reaction pathways on the Cu and Au electrodes.