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3D human pose estimation has achieved rapid progress in virtual fashion shows. Loose clothing and personalized poses in virtual fashion shows often led to unclear body joint positions and frequent joint self-occlusion. Moreover, the current methods usually focus on salient features, ignoring multi-scale high-resolution features in virtual fashion shows. This paper proposes a residual semantic graph convolutional network (GCN) with high-resolution representation, which contains high-resolution driven 2D feature extraction and semantic guidance 3D pose regression, for 3D human pose estimation in virtual fashion shows. To obtain enough valuable 2D features, we design a multi-scale module to extract global semantic information and local semantic information from high-resolution and low-resolution data respectively. Meanwhile, the feature heat map is regressed into 2D joint coordinates by integral regression. For 3D pose regression, a residual semantic GCN with non-local module, which views the 2D joint coordinates as input, is devised to explore the neighbor relationship of body joints to further improve the vague joint positions and joint self-occlusion. In the above network, each local joint is given a learnable weight to learn local semantic information gradually. Subsequently, the local semantic information is extended to the global level and is blended with obtained global semantic information via non-local operation. The experiments on COCO2017, Human3.6 M, and joint occlusion datasets demonstrate the effectiveness of our method. [ABSTRACT FROM AUTHOR]

Energy evolution is of great significance for exposing the failure mechanism of coal reservoirs and evaluating the fracturing effect. This study conducted uniaxial compression experiments with bedding intersection angle (θ) as a variable, calculated the energy and analyzed their controlling effects on coal deformation, failure and brittleness. The results show that, with increase in θ, the failure mode of coal changes from tensile fracture to shear failure, and the strength, elastic energy (Ue) and total energy (U) of coal all show a trend of first decreasing and then increasing. Based on the comprehensive criteria of the elastic energy ratio (Ue/U) and stress–strain curve, a new division method of the compression stage is proposed, and the determination of the critical point between stages can avoid the influence of human subjective factors. The transformation of Ue and external loads jointly provides the energy source for the release of dissipated energy (Ud). Ue is the main energy type in the pre-peak stage, and a significant amount of energy is converted into Ud in the failure stage. A new brittleness index was constructed by utilizing the relationship between Ue and Ud. It was found that brittleness is negatively correlated with θ and positively correlated with Ue/U at the peak point. A model of the mechanical strength of coal with structured planes has been constructed and validated by experimental data, which can be used to analyze the effect of structural planes on coal strength. When the hydraulic fracturing direction is parallel or at a low angle to the bedding plane, it is favorable for the formation of extensive fractures. [ABSTRACT FROM AUTHOR]

Crop production is a large source of atmospheric ammonia (NH3), which poses risks to air quality, human health and ecosystems1–5. However, estimating global NH3 emissions from croplands is subject to uncertainties because of data limitations, thereby limiting the accurate identification of mitigation options and efficacy4,5. Here we develop a machine learning model for generating crop-specific and spatially explicit NH3 emission factors globally (5-arcmin resolution) based on a compiled dataset of field observations. We show that global NH3 emissions from rice, wheat and maize fields in 2018 were 4.3 ± 1.0 Tg N yr−1, lower than previous estimates that did not fully consider fertilizer management practices6–9. Furthermore, spatially optimizing fertilizer management, as guided by the machine learning model, has the potential to reduce the NH3 emissions by about 38% (1.6 ± 0.4 Tg N yr−1) without altering total fertilizer nitrogen inputs. Specifically, we estimate potential NH3 emissions reductions of 47% (44–56%) for rice, 27% (24–28%) for maize and 26% (20–28%) for wheat cultivation, respectively. Under future climate change scenarios, we estimate that NH3 emissions could increase by 4.0 ± 2.7% under SSP1–2.6 and 5.5 ± 5.7% under SSP5–8.5 by 2030–2060. However, targeted fertilizer management has the potential to mitigate these increases.A machine learning model for generating crop-specific and spatially explicit NH3 emission factors globally shows that global NH3 emissions in 2018 were lower than previous estimates that did not fully consider fertilizer management practices. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) sensing methods enable highly sensitive, fast response, and label-free analysis of biomolecular interactions. For SPR sensors, sensitivity and full width at half maximum (FWHM) are two incompatible performance parameters. We propose a refractive index (RI) sensor using a dual-core photonic crystal fiber (PCF) and SPR effects to achieve high sensitivity and a narrow FWHM simultaneously. The air holes of the sensor appear in a hexagonal arrangement, and polishing technology introduces two polishing planes into the cladding. A gold film is deposited on one side of the polished plane to form a highly sensitive RI sensing channel. Five gold nanowires are deposited on the other side of the polished plane to form a RI sensing channel with a narrow FWHM. We analyzed and optimized its structural parameters using the finite element method and determined the optimal structural parameters. The numerical results demonstrate that the maximum sensitivity of the sensor is 21,000 nm/RIU with the narrowest FWHM of 31 nm. Therefore, measuring the refractive index simultaneously with two sensing channels increases the detection accuracy of the measurement. In addition, the findings further indicate that variations in structural parameters do not significantly impact the sensing performance of the sensor, which makes the production of the sensor relatively simple. In conclusion, our work provides a new research method for realizing high sensitivity and a narrow FWHM simultaneously. [ABSTRACT FROM AUTHOR]

Coalbed methane (CBM) resources are abundant in eastern Yunnan and western Guizhou of China. However, despite the vast reserves, large-scale commercial development of CBM in these areas has not yet been realized. In this study, a comprehensive analysis of the productivity of CBM wells is conducted, leveraging geological and production data from a dataset comprising 19 wells. The investigation encompasses both geological and engineering perspectives, aiming to identify and assess the various factors that significantly influence CBM well productivity. The analysis of the results reveals that the well productivity is positively correlated with the proportion of Type I coal (PTIC), the ratio of critical desorption pressure to reservoir pressure (RCRP), the gas saturation (GS), the initial permeability after reservoir stimulation (IPRS) and the permeability before gas production (PBGP). The well productivity is negatively correlated with the burial depth of the coal seam floor (BDCF) and has a complex relationship with the span of the co-production coal seam. Moreover, to achieve commercial development of CBM wells, the PTIC and GS in co-production coal seam should exceed 60%, the BDCF is less than 800 m, and RCRP, IPRS and PBGP are greater than 0.6, 2.4 mD (Millidarcy. 1 mD = 0.9869233 × 10−15 m2), and 0.3 mD, respectively. The quantitative evaluation of the sensitivity of these influencing factors on CBM well productivity in eastern Yunnan and western Guizhou is accomplished using the gray relational analysis method. The study identifies GS and PBGP as the primary controlling factors impacting the productivity of CBM wells. Building upon these findings, the research presents high productive patterns for CBM wells that emphasize coordinated control of geological and engineering aspects. This research has significant implications for the exploration and development of natural gas resources, offering potential advancements in the field. [ABSTRACT FROM AUTHOR]

A negative curvature hollow core fiber (NCHCF) refractive index (RI) sensor based on localized surface plasmon resonance (LSPR) is proposed. The gold nanowires are deposited in four cladding tubes in the y-direction, with the core region serving as the analyte channel. The full vector finite element method (FEM) is used to analyze the influence of various structural parameters on this sensor, and the structural parameters are optimized and selected. Ultimately, an average sensitivity of 9356.59 nm/RIU is accomplished within a spacious refractive index detection scope of RI = 1.28–1.43. The sensor attained a maximum sensitivity of 10,220 nm/RIU at RI = 1.36. In the bargain, there is an excellent linear correlation between the resonance wavelength and the refractive index of the analyte, with a value of 0.99901 and a factor of merit (FOM) range of 119.9563–155.9432 RIU−1, achieving a resolution of 10−6 RIU. The sensor has potential applications in various fields such as environmental protection, food safety, and medical diagnostics due to its high sensitivity, spacious detection scope, and positive linear response. [ABSTRACT FROM AUTHOR]

Edible bird's nest (EBN) mainly made of saliva that secreted by a variety of swiftlets is a kind of precious traditional Chinese medicine. EBNs from different biological and geographical origins exhibit varieties in morphology, material composition, nutritive value and commercial value. Here, we collected four different EBN samples from Huaiji, China (Grass EBN), Nha Trang, Vietnam (Imperial EBN) and East Kalimantan, Indonesia (White EBN and Feather EBN) respectively, and applied label-free quantitative MS-based proteomics technique to identify its protein composition. First, phylogenetic analysis was performed based on cytb gene to identify its biological origin. Second, a total of 37 proteins of EBNs were identified, among which there were six common proteins that detected in all samples and exhibited relatively higher content. Gene ontology analysis revealed the possible function of EBN proteins, and principal component analysis and hierarchical clustering analysis based on 37 proteins were performed to compare the difference of various EBNs. In summary, our study deciphered the common and characteristic protein components of EBNs of different origins and described their possible functions by GO enrichment analysis, which helps to establish an objective and reliable quality evaluation system. [ABSTRACT FROM AUTHOR]

Regulating electron transport rate and ion concentrations in the local microenvironment of active site can overcome the slow kinetics and unfavorable thermodynamics of CO2 electroreduction. However, simultaneous optimization of both kinetics and thermodynamics is hindered by synthetic constraints and poor mechanistic understanding. Here we leverage laser-assisted manufacturing for synthesizing CuxO bipyramids with controlled tip angles and abundant nanograins, and elucidate the mechanism of the relationship between electron transport/ion concentrations and electrocatalytic performance. Potassium/OH− adsorption tests and finite element simulations corroborate the contributions from strong electric field at the sharp tip. In situ Fourier transform infrared spectrometry and differential electrochemical mass spectrometry unveil the dynamic evolution of critical *CO/*OCCOH intermediates and product profiles, complemented with theoretical calculations that elucidate the thermodynamic contributions from improved coupling at the Cu+/Cu2+ interfaces. Through modulating the electron transport and ion concentrations, we achieve high Faradaic efficiency of 81% at ~900 mA cm−2 for C2+ products via CO2RR. Similar enhancement is also observed for nitrate reduction reaction (NITRR), achieving 81.83 mg h−1 ammonia yield rate per milligram catalyst. Coupling the CO2RR and NITRR systems demonstrates the potential for valorizing flue gases and nitrate wastes, which suggests a practical approach for carbon-nitrogen cycling. Controlling the kinetics and thermodynamics of electrochemical processes is essential to achieve high-performance multielectron reduction. Here, the authors report laser-induced copper bipyramids with abundant nanograins and controlled tip angles for enhanced multielectron CO2 and nitrate reduction. [ABSTRACT FROM AUTHOR]

The flavor-changing neutral current (FCNC) decays of charmed hadrons with missing energy (Ɇ) can serve as potentially promising hunting grounds for hints of new physics, as the standard-model backgrounds are very suppressed. A few of such processes have been searched for in recent experiments, specifically D0→ Ɇ by Belle and D0→ π0Ɇ and Λ c + → pɆ by BESIII, resulting in upper bounds on their branching fractions. We consider them to illuminate the possible contributions of the quark transition c → uɆ with a couple of invisible spinless bosons carrying away the missing energy, assuming that they are not charge conjugates of each other and hence can have unequal masses. We find that these data are complementary in that they constrain different sets of the underlying operators and do not cover the same ranges of the bosons' masses, but there are regions not yet accessible. From the allowed parameter space, we show that other D-meson decays, such as D → ρɆ, and the charmed-baryon ones Ξc → (Σ, Λ)Ɇ can have sizable branching fractions and therefore may offer further probes of the new-physics interactions. We point out the importance of D0 → γɆ which are not yet searched for but could access parts of the parameter space beyond the reach of the other modes. In addition, we look at a scenario where the invisibles are instead fermionic, namely sterile neutrinos, and a scalar leptoquark mediates c → uɆ. We discuss the implications of the aforesaid bounds for this model. The predictions we make for the various charmed-hadron decays in the different scenarios may be testable in the near future by BESIII and Belle II. [ABSTRACT FROM AUTHOR]

Constructing anion-derived solid electrolyte interphase (SEI) by recruiting anions into the solvation sheath of Li+ is extremely conducive to restrain the dendrite growth of Li metal anode. However, the presence of anions in the solvation sheath of Li+ is severely hindered by the solvents with strong coordinating ability in conventional electrolyte. Herein, we boost the content of anions in the primary solvation sheath of Li+ by employing a solvent with low donor number, 2-methyltetrahydrofuran, inducing an anion-derived SEI. As a result, the Li∥Cu cells show a high average Coulombic efficiency (> 99%) over 500 cycles and the Li∥LiFePO4 cells under a low negative/positive capacity ratio of 2:1 exhibit an impressive capacity retention of 90% after 100 cycles. This work provides insights on constructing stable anion-derived SEI and offers guidance in designing electrolytes for stable Li metal batteries. [ABSTRACT FROM AUTHOR]

Pendrin (SLC26A4) is an anion exchanger expressed in the apical membranes of selected epithelia. Pendrin ablation causes Pendred syndrome, a genetic disorder associated with sensorineural hearing loss, hypothyroid goiter, and reduced blood pressure. However its molecular structure has remained unknown, limiting our understanding of the structural basis of transport. Here, we determine the cryo-electron microscopy structures of mouse pendrin with symmetric and asymmetric homodimer conformations. The asymmetric homodimer consists of one inward-facing protomer and the other outward-facing protomer, representing coincident uptake and secretion- a unique state of pendrin as an electroneutral exchanger. The multiple conformations presented here provide an inverted alternate-access mechanism for anion exchange. The structural and functional data presented here disclose the properties of an anion exchange cleft and help understand the importance of disease-associated variants, which will shed light on the pendrin exchange mechanism. Pendrin SLC26A4 plays an important role for anion balance. Here, authors resolve cryo-EM structures of pendrin performing co-incident uptake and secretion of anions, providing a structural basis of this anion exchange mechanism. [ABSTRACT FROM AUTHOR]

Iron deficiencies are the most common nonenteric syndromes observed in patients with inflammatory bowel disease, but little is known about their impacts on immune tolerance. Here we show that homeostasis of regulatory T cells in the intestine was dependent on high cellular iron levels, which were fostered by pentanoate, a short-chain fatty acid produced by intestinal microbiota. Iron deficiencies in Treg caused by the depletion of Transferrin receptor 1, a major iron transporter, result in the abrogation of Treg in the intestine and lethal autoimmune disease. Transferrin receptor 1 is required for differentiation of c-Maf+ Treg, major constituents of intestinal Treg. Mechanistically, iron enhances the translation of HIF-2α mRNA, and HIF-2α in turn induces c-Maf expression. Importantly, microbiota-produced pentanoate promotes iron uptake and Treg differentiation in the intestine. This subsequently restores immune tolerance and ameliorated iron deficiencies in mice with colitis. Our results thus reveal an association between nutrient uptake and immune tolerance in the intestine. Iron deficiencies are a common non intestinal symptom seen in patients with irritable bowel disease. Here the authors show an associative link between microbiota assisted uptake of nutrients including iron and the promotion of immune tolerance in the intestine. [ABSTRACT FROM AUTHOR]

Van der Waals stacking of two-dimensional crystals with rotation or mismatch in lattice constants gives rise to rich physical phenomena that are closely related to the strong correlations and band topology. Twisted graphene and silicene heterobilayers have been theoretically predicted to host a tunable transport gap due to the mismatch of Dirac cones in the graphene and silicene layers. However, experimental realization of such twisted structure is challenging. Here, we report the formation of twisted graphene/silicene bilayers on Ru (0001) crystal via intercalation. Different moiré patterns form as single-crystalline graphene grows over different grains of the Ru surface. After silicon intercalation, graphene/silicene bilayers are observed with different twisting angles on top of different grains of the Ru substrate. Our work provides a new pathway towards construction of graphene based twisted heterobilayers. [ABSTRACT FROM AUTHOR]

Objective: To determine if MR neurography of the common peroneal nerve (CPN) predicts a residual motor deficit at 12-month clinical follow-up in patients presenting with foot drop. Materials and methods: A retrospective search for MR neurography cases evaluating the CPN at the knee was performed. Patients were included if they had electrodiagnostic testing (EDX) within 3 months of imaging, ankle and/or forefoot dorsiflexion weakness at presentation, and at least 12-month follow-up. Two radiologists individually evaluated nerve size (enlarged/normal), nerve signal (T2 hyperintense/normal), muscle signal (T2 hyperintense/normal), muscle bulk (normal/Goutallier 1/Goutallier > 1), and nerve and muscle enhancement. Discrepancies were resolved via consensus review. Multivariable logistical regression was used to evaluate for association between each imaging finding and a residual motor deficit at 12-month follow-up. Results: Twenty-three 3 T MRIs in 22 patients (1 bilateral, mean age 52 years, 16 male) met inclusion criteria. Eighteen cases demonstrated common peroneal neuropathy on EDX, and median duration of symptoms was 5 months. Six cases demonstrated a residual motor deficit at 12-month follow-up. Fourteen cases underwent CPN decompression (1 bilateral) within 1 year of presentation. Three cases demonstrated Goutallier > 1 anterior compartment muscle bulk. Multivariable logistical regression did not show a statistically significant association between any of the imaging findings and a residual motor deficit at 12-month follow-up. Conclusion: MR neurography did not predict a residual motor deficit at 12-month follow-up in patients presenting with foot drop, though few patients demonstrated muscle atrophy in this study. [ABSTRACT FROM AUTHOR]

Cancer stem-like cells (CSCs) are believed to be responsible for cancer recurrence and metastasis. Therefore, a therapeutic approach is needed to eliminate both rapidly proliferating differentiated cancer cells and slow-growing drug-resistant CSCs. Using established ovarian cancer cells lines as well as ovarian cancer cells isolated from a patient with high-grade drug-resistant ovarian carcinoma, we demonstrate that ovarian CSCs consistently express lower levels of NKG2D ligands (MICA/B and ULBPs) on their surfaces, a mechanism by which they evade natural killer (NK) cells' surveillance. Here, we discovered that exposure of ovarian cancer (OC) cells to SN-38 followed by 5-FU not only acts synergistically to kill the OC cells, but also makes the CSCs vulnerable to NK92 cells through upregulation of NKG2D ligands. Since systemic administration of these two drugs is marred by intolerance and instability, we engineered and isolated an adipose-derived stem cell (ASC) clone, which stably expresses carboxylesterase-2 and yeast cytosine deaminase enzymes to convert irinotecan and 5-FC prodrugs into SN-38 and 5-FU cytotoxic drugs, respectively. Co-incubation of ASCs and prodrugs with drug-resistant OC cells not only led to the death of the drug-resistant OC cells but also made them significantly vulnerable to NK92 cells. This study provides proof of principle for a combined ASC-directed targeted chemotherapy with NK92-assisted immunotherapy to eradicate drug-resistant OC cells. [ABSTRACT FROM AUTHOR]

To understand the natural gas characteristics of multi-thin coal seam, this study selected the desorbed gas of coal seams in different layers of Well A in the Wujiu depression, Hailar Basin in northeast Inner Mongolia. The results show that the heavy hydrocarbon content of desorbed gas increases significantly with the increasing depth. Methane carbon (δ13C1) and ethane carbon (δ13C2) isotope values are vertically become heavier downwards, while the δ 13 C CO 2 values did not change significantly. The kerogen is close to the III−II mixed type with the source rocks mainly deposited in a shore/shallow lake or braided-river delta front, and the gas produced has certain characteristics of oil associated gas. However, the characteristics of oil associated gas produced by the organic formed in the shallow-water environment (braided-river delta plain) are not obvious. The sandstone pore and fracture systems interbedded with multi-thin coal seam are well developed. And it is conducive to the migration of methanogenic micro-organisms to coal seams via groundwater, making it easier to produce biogenic gas under this geological condition. During the burial evolution of coal-bearing strata in the study area, when the burial depth reaches the maximum, there are significant differences in the paleotemperature experienced by different vertical coal seams, caused by a high-paleogeothermal gradient, increasing the δ13C2 of desorbed gas with increasing depth. The above research indicates that there is less biogenic gas in the multi-thin coal seams with relatively developed mudstone, and the multi-thin coal seams with relatively developed sandstones have obvious biogenic gas characteristics. Therefore, for the exploration and development of biogenic gas in low-rank multi-thin coal seams, it is necessary to give priority to the layer with high sandstone content. [ABSTRACT FROM AUTHOR]

The rare incidence of mitral regurgitation (MR) caused by mitral valve prolapse in children lacks clinical management experience. In this study, we present our experience in surgical management and the difference between isolated anterior mitral leaflet (AML), posterior mitral leaflet (PML), and bileaflet prolapse in pediatric patients. Between January 2014 and February 2021, 52 pediatric patients, aged 7.04 ± 4.02 years (ranged from 0.17 to 14 years), were diagnosed as moderately severe (11, 21.2%) or severe (41, 78.8%) MR, of which, 34 (65.4%) were owing to AML prolapse, one (1.9%) was PML prolapse, and 17 (32.7%) caused by bileaflet prolapse. All had received mitral valve repair, and were divided into the group of AML prolapse and bileaflet prolapse. Demographic and clinical characteristics of all patients were retrospectively collected and analyzed. The left ventricular diameter in the bileaflet group was significantly larger than the AML group (4.04 ± 0.73 cm vs. 3.45 ± 0.75 cm, P = 0.026). The median follow-up time was 33 months (ranged from 6 to 88 months). The postoperative and follow-up results had no significant difference between two groups. And only 2 patients received reoperation due to posterior annuloplasty ring dehiscence. For pediatric patients, the majority of the patients had isolated AML prolapse instead of PML prolapse. There was no difference in recurrent regurgitation or reoperation between isolated AML and bileaflet prolapse after MV repair, and we suggest more aggressive surgical strategy should be considered in pediatric patients with bileaflet prolapse than AML prolapse. [ABSTRACT FROM AUTHOR]

Majorana zero modes (MZMs) obey non-Abelian statistics and are considered building blocks for constructing topological qubits1,2. Iron-based superconductors with topological bandstructures have emerged as promising hosting materials, because isolated candidate MZMs in the quantum limit have been observed inside the topological vortex cores3–9. However, these materials suffer from issues related to alloying induced disorder, uncontrolled vortex lattices10–13 and a low yield of topological vortices5–8. Here we report the formation of an ordered and tunable MZM lattice in naturally strained stoichiometric LiFeAs by scanning tunnelling microscopy/spectroscopy. We observe biaxial charge density wave (CDW) stripes along the Fe–Fe and As–As directions in the strained regions. The vortices are pinned on the CDW stripes in the As–As direction and form an ordered lattice. We detect that more than 90 per cent of the vortices are topological and possess the characteristics of isolated MZMs at the vortex centre, forming an ordered MZM lattice with the density and the geometry tunable by an external magnetic field. Notably, with decreasing the spacing of neighbouring vortices, the MZMs start to couple with each other. Our findings provide a pathway towards tunable and ordered MZM lattices as a platform for future topological quantum computation.An ordered Majorana-zero-mode lattice in naturally strained LiFeAs is reported, formed by vortices pinned to charge density wave stripes, and with density and geometry tunable by application of an external magnetic field. [ABSTRACT FROM AUTHOR]

In Weyl semimetals, charge density wave (CDW) order can spontaneously break the chiral symmetry, gap out the Weyl nodes, and drive the material into the axion insulating phase. Investigations have however been limited since CDWs are rarely seen in Weyl semimetals. Here, using scanning tunneling microscopy/spectroscopy (STM/S), we report the discovery of a novel unidirectional CDW order on the (001) surface of chiral crystal CoSi – a unique Weyl semimetal with unconventional chiral fermions. The CDW is incommensurate with both lattice momentum and crystalline symmetry directions, and exhibits an intra unit cell π phase shift in the layer stacking direction. The tunneling spectrum shows a particle-hole asymmetric V-shaped energy gap around the Fermi level that modulates spatially with the CDW wave vector. Combined with first-principle calculations, we identify that the CDW is locked to the crystal chirality and is related by a mirror reflection between the two enantiomers of the chiral crystal. Our findings reveal a novel correlated topological quantum state in chiral CoSi crystals and raise the potential for exploring the unprecedented physical behaviors of unconventional chiral fermions. The interplay between electron correlation and topological properties remains less understood. Here, the authors report a charge density wave (CDW) order on the (001) surface of a Weyl semimetal CoSi, where an energy gap modulates spatially with the CDW wave vector. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials with defects are desired for catalysis after the adsorption of monodispersed noble metal atoms. High-performance catalysts with the absolute value of Gibbs free energy (∣∆GH∣) close to zero, is one of the ultimate goals in the catalytic field. Here, we report the formation of monolayer titanium selenide (TiSe2) with line defects. The low-temperature scanning tunneling microscopy/spectroscopy (STM/S) measurements revealed the structure and electronic states of the line defect. Density functional theory (DFT) calculation results confirmed that the line defects were induced by selenium vacancies and the STM simulation was in good agreement with the experimental results. Further, DFT calculations show that monolayer TiSe2 with line defects have good catalytic activity for hydrogen evolution reaction (HER). If the defects are decorated with single Pt atom, the HER catalytic activity will be enhanced dramatically (∣∆GH∣ = 0.006 eV), which is much better than Pt metal (∣∆GH∣ = 0.09 eV). Line defects in monolayer TiSe2/Au(111) provide a wonderful platform for the design of high-performance catalysts. [ABSTRACT FROM AUTHOR]

Sodium salicylate is an anti-inflammatory medication with a side-effect of tinnitus. Here, we used mouse cochlear cultures to explore the effects of salicylate treatment on cochlear inner hair cells (IHCs). We found that IHCs showed significant damage after exposure to a high concentration of salicylate. Whole-cell patch clamp recordings showed that 1–5 mmol/L salicylate did not affect the exocytosis of IHCs, indicating that IHCs are not involved in tinnitus generation by enhancing their neuronal input. Instead, salicylate induced a larger peak amplitude, a more negative half-activation voltage, and a steeper slope factor of Ca2+ current. Using noise analysis of Ca2+ tail currents and qRT-PCR, we further found that salicylate increased the number of Ca2+ channels along with CaV1.3 expression. All these changes could act synergistically to enhance the Ca2+ influx into IHCs. Inhibition of intracellular Ca2+ overload significantly attenuated IHC death after 10 mmol/L salicylate treatment. These results implicate a cellular mechanism for tinnitus generation in the peripheral auditory system. [ABSTRACT FROM AUTHOR]

Androgenic alopecia (AGA) has a high incidence. Excess dihydrotestosterone in blood capillaries, which is converted from testosterone by 5α-reductase, is an AGA causative factor. We identified the inhibitory activity of four Polygonum multiflorum compounds against 5α-reductase via high-performance liquid chromatography, and the results showed that Physcion was a potent 5α-reductase inhibitor. Additionally, we found that through inhibiting 5α-reductase expression, Physcion could shorten the time of dorsal skin darkening and hair growth, improve hair follicle morphology, and significantly increase hair follicle count. Eventually, through molecular docking study, we found the binding energy and molecular interactions between Physcion and 5α-reductase type II. These results suggested that Physcion is a potent 5α-reductase inhibitor, as well as a new natural medicine for treating AGA. [ABSTRACT FROM AUTHOR]

The future sixth generation (6G) is going to face the significant challenges of massive connections and green communication. Recently, reconfigurable intelligent surfaces (RIS) and non-orthogonal multiple access (NOMA) have been proposed as two key technologies to solve the above problems. Motivated by this fact, we consider a downlink RIS-aided NOMA system, where the source aims to communicate with the two NOMA users via RIS. Considering future network supporting real-time service, we investigate the system performance with the view of effective capacity (EC), which is an important evaluation metric of delay sensitive systems. Specifically, we derive the analytical expressions of the EC of the near and far users. To obtain more useful insights, we deduce the analytical approximation expressions of the EC in the low signal-to-noise-ratio approximation by utilizing Taylor expansion. Moreover, we provide the results of orthogonal multiple access (OMA) for the purpose of comparison. It is found that (1) The number of RIS components and the transmission power of the source have important effects on the performance of the considered system; (2) Compared with OMA, NOMA system has higher EC due to the short transmission time. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of intravenous (IV) contrast on sensitivity, specificity, and accuracy of magnetic resonance (MR) neurography of the knee with attention to the common peroneal nerve (CPN) in identifying nerve lesions and active muscle denervation changes. Materials and methods: A retrospective search for contrast-enhanced MR neurography cases evaluating the CPN at the knee was performed. Patients with electrodiagnostic testing (EDX) within 3 months of imaging were included and those with relevant prior surgery were excluded. Two radiologists independently reviewed non-contrast sequences and then 4 weeks later evaluated non-contrast and contrast sequences. McNemar's tests were performed to detect a difference between non-contrast only and combined non-contrast and contrast sequences in identifying nerve lesions and active muscle denervation changes using EDX as the reference standard. Results: Forty-four exams in 42 patients (2 bilateral) were included. Twenty-eight cases had common peroneal neuropathy and 29, 21, and 9 cases had active denervation changes in the anterior, lateral, and posterior compartment/proximal muscles respectively on EDX. Sensitivity, specificity, and accuracy of non-contrast versus combined non-contrast and contrast sequences for common peroneal neuropathy were 50.0%, 56.2%, and 52.3% versus 50.0%, 56.2%, and 52.3% for reader 1 and 57.1%, 50.0%, and 54.5% versus 64.3%, 56.2%, and 61.4% for reader 2. Sensitivity, specificity, and accuracy of non-contrast and combined non-contrast and contrast sequences in identifying active denervation changes for anterior, lateral, and posterior compartment muscles were not significantly different. McNemar's tests were all negative. Conclusion: IV contrast does not improve the ability of MR neurography to detect CPN lesions or active muscle denervation changes. [ABSTRACT FROM AUTHOR]

In this study, the pore characteristics and the factors of maximum methane adsorption capacity (MAC) of mudstone in the early diagenetic stage (EDS) and the contribution rate of clay mineral (CM) adsorption were analyzed. In addition, the adsorption coupling effect of CM and organic matter (OM) was discussed. Studies have shown that pores of coal measure mudstone in the early diagenesis stage are mainly small pores with slanted platelike staggered and overlapped pores, with more pore opening directions. The main controlling factors of the maximum MAC of mudstone are OM and CM, and the direct expression is the pore surface area. In the EDS, the contribution rate of CM in mudstone is lower, while the contribution rate of OM to the MAC of mudstone is higher. There is an adsorption coupling effect of CM composition and OM. OM in mudstone is scattered, and the CMs have a supporting effect, which leads to OM in mudstone having a large contact area with the open space and has many effective pores. OM in coal is concentrated, and the surface area of OM per unit volume is small (compared with OM in mudstone). The compaction and deformation characteristics of CMs have a plugging/sealing effect on the pores of OM in the coal, which makes the effective pores of OM per unit volume in coal lower than those in mudstone. [ABSTRACT FROM AUTHOR]

The transition metal kagome lattice materials host frustrated, correlated and topological quantum states of matter1–9. Recently, a new family of vanadium-based kagome metals, AV3Sb5 (A = K, Rb or Cs), with topological band structures has been discovered10,11. These layered compounds are nonmagnetic and undergo charge density wave transitions before developing superconductivity at low temperatures11–19. Here we report the observation of unconventional superconductivity and a pair density wave (PDW) in CsV3Sb5 using scanning tunnelling microscope/spectroscopy and Josephson scanning tunnelling spectroscopy. We find that CsV3Sb5 exhibits a V-shaped pairing gap Δ ~ 0.5 meV and is a strong-coupling superconductor (2Δ/kBTc ~ 5) that coexists with 4a0 unidirectional and 2a0 × 2a0 charge order. Remarkably, we discover a 3Q PDW accompanied by bidirectional 4a0/3 spatial modulations of the superconducting gap, coherence peak and gap depth in the tunnelling conductance. We term this novel quantum state a roton PDW associated with an underlying vortex–antivortex lattice that can account for the observed conductance modulations. Probing the electronic states in the vortex halo in an applied magnetic field, in strong field that suppresses superconductivity and in zero field above Tc, reveals that the PDW is a primary state responsible for an emergent pseudogap and intertwined electronic order. Our findings show striking analogies and distinctions to the phenomenology of high-Tc cuprate superconductors, and provide groundwork for understanding the microscopic origin of correlated electronic states and superconductivity in vanadium-based kagome metals.A study reports unconventional superconductivity and a pair density wave in the kagome superconductor CsV3Sb5, and provides a basis for understanding the microscopic origin of correlated electronic states and superconductivity in vanadium-based kagome metals. [ABSTRACT FROM AUTHOR]

For iron-based superconductors, the phase diagrams under pressure or strain exhibit emergent phenomena between unconventional superconductivity and other electronic orders, varying in different systems. As a stoichiometric superconductor, LiFeAs has no structure phase transitions or entangled electronic states, which manifests an ideal platform to explore the pressure or strain effect on unconventional superconductivity. Here, we observe two types of superconducting states controlled by orientations of local wrinkles on the surface of LiFeAs. Using scanning tunneling microscopy/spectroscopy, we find type-I wrinkles enlarge the superconducting gaps and enhance the transition temperature, whereas type-II wrinkles significantly suppress the superconducting gaps. The vortices on wrinkles show a C2 symmetry, indicating the strain effects on the wrinkles. By statistics, we find that the two types of wrinkles are categorized by their orientations. Our results demonstrate that the local strain effect with different directions can tune the superconducting order parameter of LiFeAs very differently, suggesting that the band shifting induced by directional pressure may play an important role in iron-based superconductivity. The evolution of superconductivity in LiFeAs with respect to pressure or strain remains elusive. Here, the authors observe different response of superconducting states due to different orientations of local wrinkles on the surface of LiFeAs. [ABSTRACT FROM AUTHOR]

As a new type of iron-based superconductor, CaKFe4As4 has recently been demonstrated to be a promising platform for observing Majorana zero modes (MZMs). The surface of CaKFe4As4 plays an important role in realizing the MZM since it hosts superconducting topological surface states. However, due to the complicated crystal structure, the terminal surface of CaKFe4As4 has not been determined yet. Here, by using scanning tunneling microscopy/spectroscopy (STM/S), we find that there are two types of surface structure in CaKFe4As4. Bias-dependent atomic resolution images show an evolvement from 2 × 2 superstructure with respect to the As lattice into 1 × 1 when the tip is brought close to the surface, revealing the sublattice of missing As atoms. Together with the first-principles calculations, we show that the surface As layer has a buckled structure. Our findings provide insight to future surface study of CaKFe4As4 as well as other iron-pnictide superconductors. [ABSTRACT FROM AUTHOR]

An equity warrant allows warrant holders to buy stocks of listed companies at a certain price on a promissory day. Classified by the time of exercise right, there are two types of equity warrant, namely European equity warrants and American equity warrants. The European equity warrants allow the buyers to exercise their rights only on the expiring date. In contrast, American warrants enable the buyers to exercise their rights before or on the expiring date. Based on the assumption that the firm's value follows an uncertain exponential Ornstein–Uhlenbeck process instead of a stochastic process, this paper mainly solves the pricing problems of European and American equity warrants. The most significant advantage of this paper is offering the corresponding formulas to calculate equity warrants, which are not complicated compared with the classical stochastic financial theory. Besides, the minimum cover estimation method is applied to estimate the parameters in an uncertain exponential Ornstein–Uhlenbeck equation, and a simulation example is provided to show the effectiveness of the proposed pricing formulae. [ABSTRACT FROM AUTHOR]

Protein lysine acetylation (Kac) is an important post-translational modification in both animal and plant cells. Global Kac identification has been performed at the proteomic level in various species. However, the study of Kac in oil and resource plant species is relatively limited. Soybean is a globally important oil crop and resouce plant. In the present study, lysine acetylome analysis was performed in soybean leaves with proteomics techniques. Various bioinformatics analyses were performed to illustrate the structure and function of these Kac sites and proteins. Totally, 3148 acetylation sites in 1538 proteins were detected. Motif analysis of these Kac modified peptides extracted 17 conserved motifs. These Kac modified protein showed a wide subcellular location and functional distribution. Chloroplast is the primary subcellular location and cellular component where Kac proteins were localized. Function and pathways analyses indicated a plenty of biological processes and metabolism pathways potentially be influenced by Kac modification. Ribosome activity and protein biosynthesis, carbohydrate and energy metabolism, photosynthesis and fatty acid metabolism may be regulated by Kac modification in soybean leaves. Our study suggests Kac plays an important role in soybean physiology and biology, which is an available resource and reference of Kac function and structure characterization in oil crop and resource plant, as well as in plant kingdom. [ABSTRACT FROM AUTHOR]

In this study, the fibrous mesoporous silica F-SiO2 was functionalized with 3-aminopropyltriethoxysilane (APTES). The reversible thermochromic composites of fibrous mesoporous silica (F-SiO2) and amino group-modified fibrous mesoporous silica (F-SiO2-NH2) microspheres loaded with cresol red-boric acid (CR-BA) were termed as S2 (F-SiO2/CR-BA) and SN2 (F-SiO2-NH2/CR-BA), respectively. The materials obtained were characterized by infrared spectroscopy, transmission electron microscopy, scanning and transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. The fibrous morphology of this rigid carrier was maintained after loading with the CR-BA composite system. Owing to the APTES modification, the F-SiO2-NH2/CR-BA composites underwent more severe color changes than the F-SiO2/CR-BA composites. In addition, the F-SiO2-NH2/CR-BA composites can recover the original color in only 210 s, illustrating excellent reversibility. [ABSTRACT FROM AUTHOR]

Excessive inflammatory responses induced upon SARS-CoV-2 infection are associated with severe symptoms of COVID-19. Inflammasomes activated in response to SARS-CoV-2 infection are also associated with COVID-19 severity. Here, we show a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation. N protein facilitates maturation of proinflammatory cytokines and induces proinflammatory responses in cultured cells and mice. Mechanistically, N protein interacts directly with NLRP3 protein, promotes the binding of NLRP3 with ASC, and facilitates NLRP3 inflammasome assembly. More importantly, N protein aggravates lung injury, accelerates death in sepsis and acute inflammation mouse models, and promotes IL-1β and IL-6 activation in mice. Notably, N-induced lung injury and cytokine production are blocked by MCC950 (a specific inhibitor of NLRP3) and Ac-YVAD-cmk (an inhibitor of caspase-1). Therefore, this study reveals a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation and induces excessive inflammatory responses. SARS-CoV-2 infection has been shown to drive NLRP3 inflammasome activation and thereby cytokine storm, but how it does so is unclear. Here the authors show that the viral N protein can bind to NLRP3, resulting in enhanced interaction with ASC and thereby with the NLRP3 inflammasome. [ABSTRACT FROM AUTHOR]

The iron-based superconductor is emerging as a promising platform for Majorana zero mode, which can be used to implement topological quantum computation. One of the most significant advances of this platform is the appearance of large vortex level spacing that strongly protects Majorana zero mode from other low-lying quasiparticles. Despite the advantages in the context of physics research, the inhomogeneity of various aspects hampers the practical construction of topological qubits in the compounds studied so far. Here we show that the stoichiometric superconductor LiFeAs is a good candidate to overcome this obstacle. By using scanning tunneling microscopy, we discover that the Majorana zero modes, which are absent on the natural clean surface, can appear in vortices influenced by native impurities. Our detailed analysis reveals a new mechanism for the emergence of those Majorana zero modes, i.e. native tuning of bulk Dirac fermions. The discovery of Majorana zero modes in this homogeneous material, with a promise of tunability, offers an ideal material platform for manipulating and braiding Majorana zero modes, pushing one step forward towards topological quantum computation. Despite the discovery of Majorana zero modes (MZM) in iron-based superconductors, sample inhomogeneity may destroy MZMs during braiding. Here, authors observe MZM in impurity-assisted vortices due to tuning of the bulk Dirac fermions in a homogeneous superconductor LiFeAs. [ABSTRACT FROM AUTHOR]

In this paper, we study the FCNC decay processes of B and B c meson, in which one invisible particle is emitted. Both the spin-0 and spin-1 cases are considered. The model-independent effective Lagrangian is introduced to describe the coupling between the light invisible boson and quarks. The constraints of the coupling coefficients are extracted by experimental upper limits of the missing energy in B meson decays. The bounds are used to predict the upper limits of branching fractions of corresponding B c decays, which are of the order of 10 - 6 or 10 - 5 when final meson is pseudoscalar or vector, respectively. The maximum branch ratios are achieved when m χ ≈ 3.5 –4 GeV, where m χ is the mass of the invisible particle. [ABSTRACT FROM AUTHOR]

The objective of this work is to study the effect of strain gradient, electric field gradient, and magnetic field gradient on the potential and field distributions of multiferroic fibrous composites subjected to generalized anti-plane shear deformation. A detailed energy variational formulation with strain, strain gradient, electric field, electric field gradient, magnetic field, and magnetic field gradient as independent variables is provided, and the equilibrium equations with the complete boundary conditions are simultaneously determined. Three internal characteristic lengths of the underlying microstructure are introduced in the constitutive equations. The general solutions in cylindrical polar coordinates consisting of the modified Bessel functions of first and second kind are derived. One inclusion problem's solution is also obtained. The derived solutions are applied to a CoFe 2 O 4 -PZT-4 composite to demonstrate the effect of strain gradient, electric field gradient, and magnetic field gradient. Numerical results provide insights into the role of characteristic lengths on the potential and field distributions of a multiferroic fibrous composite. [ABSTRACT FROM AUTHOR]

The desorbed gas composition and δ13C(CH4) and δD(CH4) of five coal groups in Well DE-A of the Labudalin Basin in northeastern Inner Mongolia show that the δ13C(CH4) and δD(CH4) are heavy, and significantly heavier in some layers, whereas the overall δ13C(CO2) is abnormally light. Based on coalfield exploration data, this study analyzes the characteristics and control factors of methane isotope alienation of shallow-buried low-rank multiple coal seams in a small coal-bearing depression. The maximum buried depth of the coal seam in the Derbu coalfield is less than 600 m, and the coal rank is sub-bituminous coal. The carbon isotope composition (δ13C(CH4)) of CBM varies from − 56.3 to − 39.8‰, wherein the arithmetic average is − 48.72‰. Compared with coal seams of the same metamorphic degree, the δ13C(CH4) in Derbu is relatively heavy, wherein different coal groups and different coal seams of the same coal group have different characteristics, and the δ13C(CO2) is relatively light. Studies have shown that the existence of thermogenic gas, anaerobic oxidation of methane microorganisms, and desorption-fractionation of methane isotopes in Well DE-A are causes for the heavier δ13C(CH4) and δD(CH4). Note that the thermal cause is the basis for the heavier δ13C(CH4) of the gas sample, while the carbon isotope fractionation of methane and oxidation of microorganisms further aggravate the δ13C(CH4). The preservation conditions, such as lithofacies combination sequence and hydrogeological conditions, of different coal formations are also important factors influencing δ13C(CH4) differentiation, and the superposition and coupling of various reasons make this differentiation more obvious. By comparing the geological characteristics of Well DE-A with the vertical variation characteristics of carbon isotopes in the desorbed methane of the Surat Basin, it was concluded that the vertical variation of the desorbed gas sample in shallow-buried low-rank multiple coal seams has complex characteristics. In addition to maturity, local horizons are more obviously controlled by lithologic association and hydrological characteristics. Especially for small coal-bearing depressions or coal-bearing strata near outcrops with shallow-buried depth, the horizontal distance between the outcrop line of different coal formations and target well locations is obviously short. Thus, surface water and surface microorganisms can migrate along the short high permeability layers (coal seam or sandstone layer), and influence the coal-bearing seam. Meanwhile, different groundwater dynamic conditions also result in the transformation of desorbed gas in different coal groups, revealing variation in the methane carbon isotopes. [ABSTRACT FROM AUTHOR]

Braiding Majorana zero modes is essential for fault-tolerant topological quantum computing. Iron-based superconductors with nontrivial band topology have recently emerged as a surprisingly promising platform for creating distinct Majorana zero modes in magnetic vortices in a single material and at relatively high temperatures. The magnetic field-induced Abrikosov vortex lattice makes it difficult to braid a set of Majorana zero modes or to study the coupling of a Majorana doublet due to overlapping wave functions. Here we report the observation of the proposed quantum anomalous vortex with integer quantized vortex core states and the Majorana zero mode induced by magnetic Fe adatoms deposited on the surface. We observe its hybridization with a nearby field-induced Majorana vortex in iron-based superconductor FeTe0.55Se0.45. We also observe vortex-free Yu-Shiba-Rusinov bound states at the Fe adatoms with a weaker coupling to the substrate, and discover a reversible transition between Yu-Shiba-Rusinov states and Majorana zero mode by manipulating the exchange coupling strength. The dual origin of the Majorana zero modes, from magnetic adatoms and external magnetic field, provides a new single-material platform for studying their interactions and braiding in superconductors bearing topological band structures. Braiding Majorana modes is essential for topological quantum computing, but it remains difficult to find a suitable platform. Here, the authors report the evidence of hybridization between field-induced and magnetic adatom induced Majorana modes in an iron-based superconductor FeTe0.55Se0.45, providing a possible single-material platform for braiding Majorana modes. [ABSTRACT FROM AUTHOR]

Optimal pH conditions for efficient artificial photosynthesis, hydrogen/oxygen evolution reactions, and photoreduction of carbon dioxide are now successfully achievable with catalytic bipolar membranes-integrated water dissociation and in-situ acid-base generations. However, inefficiency and instability are severe issues in state-of-the-art membranes, which need to urgently resolve with systematic membrane designs and innovative, inexpensive junctional catalysts. Here we show a shielding and in-situ formation strategy of fully-interconnected earth-abundant goethite Fe+3O(OH) catalyst, which lowers the activation energy barrier from 5.15 to 1.06 eV per HO − H bond and fabricates energy-efficient, cost-effective, and durable shielded catalytic bipolar membranes. Small water dissociation voltages at limiting current density (ULCD: 0.8 V) and 100 mA cm−2 (U100: 1.1 V), outstanding cyclic stability at 637 mA cm−2, long-time electro-stability, and fast acid-base generations (H2SO4: 3.9 ± 0.19 and NaOH: 4.4 ± 0.21 M m−2 min−1 at 100 mA cm−2) infer confident potential use of the novel bipolar membranes in emerging sustainable technologies. Bipolar membranes integrated water dissociation and acid-base generations have great potential in emerging sustainable technologies but remains inefficient. Here, the authors circumvent this inefficiency and instability of the membranes by developing polyaniline shielded catalytic bipolar membranes. [ABSTRACT FROM AUTHOR]

Purpose: To determine the feasibility of ultra-short echo time (UTE) MRA for assessment of inferior vena cava (IVC) filters and evaluate the impact of different imaging protocols at 3.0 T, using conventional Cartesian MRA (cMRA) as the reference standard. Methods: Patients with IVC-filters were recruited for this prospective IRB-approved, HIPAA-compliant study. Subjects underwent contrast-enhanced breath-held and a free-breathing 3D radial acquisition UTE-MRA (bhUTE, fbUTE) at three different flip angles (FA: 10°, 15°, 20°) to optimize T1-weighted image quality. Two radiologists performed a direct comparison consensus reading to assess the optimal FA. Image quality (IQ) of both UTE techniques at the best FA was rated independently on a 4-point Likert scale (0 = non-diagnostic, 3 = excellent) and compared to 3D T1-weighted breath-held cMRA. Results: Nine subjects were recruited. Low FAs of 10° were rated best for both UTE techniques. fbUTE was excellent (3, IQR: 2; 3) and significantly better for IVC-filter depiction than cMRA (2, IQR: 0.75; 2, p = 0.001) and bhUTE (1.5, IQR: 0.75; 2, p < 0.001). Both UTE techniques showed significantly less filter-related artifacts (fbUTE: 28%, bhUTE: 33%) than cMRA (89%, p = 0.001 and p = 0.002, respectively). However, IQ of bhUTE was generally degraded due to high image noise and low image contrast. IQ of the IVC venogram was best with cMRA. Clinically relevant signal voids were only observed with the cage-shaped OptEase filter. Conclusion: UTE-MRA is feasible at 3.0 T for the assessment of IVC-filters, particularly using a free-breathing protocol. Larger studies are needed to investigate the clinical utility of free-breathing UTE-MRA for assessment of IVC-filter-related complications. [ABSTRACT FROM AUTHOR]

For efficient enantioseparation, eight organic–inorganic hybrid bead-type chiral packing materials (CPMs) with high organic contents have been developed using cellulose tris(3,5-dimethylphenylcarbamates) bearing small amount of 3-(triethoxysilyl)propyl groups and tetraethyl orthosilicate by a modified Stöber process in the basic condition. The hybrid beads could be formed more efficiently in the basic condition without using surfactant, compared to that in the acidic condition. The preparation conditions, including type and amount of catalyst, amount of water and temperature, significantly affected the organic contents and morphology of the hybrid CPMs. Their chiral recognition properties were then examined by high-performance liquid chromatography. The obtained hybrid CPMs with a higher organic content possessed better enantioseparation ability than the traditional CPMs and previous analogue derived from the acidic condition. For some racemates, the hybrid CPMs exhibited even higher enantioselectivity than the commercial Chiralpak IB N, which is one of the most powerful immobilized-type CPMs and prepared from cellulose tris(3,5-dimethylphenylcarbamate). [ABSTRACT FROM AUTHOR]

SurA is the major chaperone of outer membrane proteins (OMPs) in the periplasm. The molecular mechanism when SurA performs its chaperoning function is still unclear. Here, a purification-after-crosslinking (PAC) procedure was combined with single-molecule fluorescence resonance energy transfer (smFRET) to probe the conformations of SurA and OmpC in their complex. We found that SurA in the free state rearranges itself based on the crystal structure, except that the P2 domain moves towards the core domain with two major positions, forming a clamp-like conformation to accommodate OmpC. The obvious rearrangement of the P2 domain of SurA helps SurA to hold OmpC. OmpC attaches to SurA randomly and has the propensity to be near the middle part of the crevice. The noncollapsed and disordered conformations of OMPs provided by the OMPs·SurA complex are important to the subsequent delivery and folding process. [ABSTRACT FROM AUTHOR]

The geochemical information of produced water from coalbed methane (CBM) wells is abundant in geological significance. Based on the conventional ions, hydrogen and oxygen isotopes (δD and δ18O) and trace element tests of 27 produced water samples from CBM wells, the geochemical identification of the source and environment of produced water from CBM wells and its productivity significance have been analysed. The following conclusions have been drawn: CBM produced water can be divided into three categories, namely, polluted water from frac fluids, polluted surface water and formation water. The formation water has low Cl- concentration, low total dissolved solids (TDS) concentration, and light δD and δ18O. The water polluted by frac fluid has high Cl- and TDS concentrationt, and heavy δD and δ18O. The polluted surface water has high SO42- and light δD and δ18O. CBM groun dwate r environments can be divided into confined and unconfined systems. The confined system is characterized by low Na+/Cl- value, high (Cl- - Na+)/Mg2+ value, a general absence of SO42-, high Sr and Ba and low F. The unconfined system is characterized by high Na+/Cl- value, low (Cl- - Na+)/Mg2+ value, low SO42-, low Sr and Ba and high F. Constructing a cross plot with the new D drift index (d') value and Cl- concentration can further identify four types of source-water environments: an unconfined formation water system, an unconfined surface water system, a confined system heavily polluted by frac fluids, and a confined system only slightly polluted by frac fluids. The unconfined system often produces more formation water and has high CBM production. The confined system often produces water more heavily polluted by frac fluids and is low in CBM production. The fitting formulas of hydrochemical productivity have been established for daily CBM and water production of CBM wells. [ABSTRACT FROM AUTHOR]