Development and internal validation of a model for predicting cefoperazone/sulbactam-associated coagulation disorders in Chinese inpatients.

BACKGROUND AND AIM: The use of cefoperazone/sulbactam (CPZ/SAM) could commonly cause vitamin K-dependent coagulation disorders and even hemorrhage sometimes. However, there is a lack of prediction tools estimating the risk for this. This study aimed at developing and internally validating a model for predicting CPZ/SAM-associated coagulation disorders in Chinese inpatients. METHODS: A case-control study was conducted in 11,092 adult inpatients admitted to a Chinese general hospital between 2020 and 2021 and treated with CPZ/SAM. Patients with CPZ/SAM-associated coagulation disorders were identified through the Adverse Drug Events Active Surveillance and Assessment System-II and subsequent manual evaluation. Controls were selected from eligible patients who didn't develop coagulation disorders after CPZ/SAM therapy, with a 1:1 propensity score matching. The final predictors were obtained by univariable and multivariable logistic regression analyses. Internal validation and calibration for the model were performed using 1000 bootstrap resamplings. RESULTS: 258 patients were identified as CPZ/SAM-associated coagulation disorders in 2184 patients eligible for inclusions and exclusions and the incidence was 11.8%. A final population of 252 cases and 252 controls was included for model development and validation. Malnutrition (OR = 2.41 (1.56-3.77)), history of recent bleeding (OR = 1.95 (1.32-2.90)), treatment duration (OR = 1.10 (1.07-1.14)), combination with carbapenems (OR = 4.43 (1.85-11.88)), and serum creatinine (OR = 1.01 (1.00-1.01)) were identified as final predictors. The model showed good discrimination, calibration, and clinical practicality, with the validated area under the receiver operating characteristic curve being 0.723 (0.683-0.770). CONCLUSIONS: The model with good performance quantifies the risk for CPZ/SAM-associated coagulation disorders, and may support individual assessment and interventions to mitigate the risk after external validation.

Atomistic Modeling of Quaternized Chitosan Head Groups: Insights into Chemical Stability and Ion Transport for Anion Exchange Membrane Applications.

The chemical stability and ion transport properties of quaternized chitosan (QCS)-based anion exchange membranes (AEMs) were explored using Density Functional Theory (DFT) calculations and all-atom molecular dynamics (MD) simulations. DFT calculations of LUMO energies, reaction energies, and activation energies revealed an increasing stability trend among the head groups: propyl trimethyl ammonium chitosan (C) < oxy propyl trimethyl ammonium chitosan (B) < 2-hydroxy propyl trimethyl ammonium chitosan (A) at hydration levels (HLs) of 0 and 3. Subsequently, all-atom MD simulations evaluated the diffusion of hydroxide ions (OH-) through mean square displacement (MSD) versus time curves. The diffusion coefficients of OH- ions for the three types of QCS (A, B, and C) were observed to increase monotonically with HLs ranging from 3 to 15 and temperatures from 298 K to 350 K. Across different HLs and temperatures, the three QCS variants exhibited comparable diffusion coefficients, underlining their effectiveness in vehicular transport of OH- ions.

miRNAs: Primary modulators of plant drought tolerance.

Drought is a principal environmental factor that affects the growth and development of plants. Accordingly, plants have evolved adaptive mechanisms to cope with adverse environmental conditions. One of the mechanisms is gene regulation mediated by microRNAs (miRNAs). miRNAs are regarded as primary modulators of gene expression at the post-transcriptional level and have been shown to participate in drought stress response, including ABA response, auxin signaling, antioxidant defense, and osmotic regulation through downregulating the corresponding targets. miRNA-based genetic reconstructions have the potential to improve the tolerance of plants to drought. However, there are few precise classification and discussion of miRNAs in specific response behaviors to drought stress and their applications. This review summarized and discussed the specific response behaviors of miRNAs under drought stress and the role of miRNAs as regulators in the response of plants to drought and highlighted that the modification of miRNAs might effectively improve the tolerance of plants to drought.

Molecular dynamics simulation on regulation of liquid-liquid phase separation of repetitive peptides.

Understanding the intricate interactions governing protein and peptide behavior in liquid-liquid phase separation (LLPS) is crucial for unraveling biological functions and dysfunctions. This study employs a residue-leveled coarse-grained molecular dynamics approach to simulate the phase separation of repetitive polyproline and polyarginine peptides (poly PR) with varying lengths and sequences in solution, considering different concentrations and temperatures. Our findings highlight the crucial role of sequence order in promoting LLPS in peptides with identical lengths of repetitive sequences. Interestingly, repetitive peptides containing fewer than 10 polyarginine repeats exhibit no LLPS, even at salt concentrations up to 3 M. Notably, our simulations align with experimental observations, pinpointing a salt concentration of 2.7 M for PR25-induced LLPS. Utilizing the same methodology, we predict the required salt concentrations for LLPS induction as 1.2 M, 1.5 M, and 2.7 M for PR12, PR15, and PR35, respectively. These predictions demonstrate good agreement with experimental results. Extending our investigation to include the peptide glutamine and arginine (GR15) in DNA solution, our simulations mirror experimental observations of phase separation. To unveil the molecular forces steering peptide phase separation, we introduce a dielectric constant modifier and hydrophobicity disruptor into poly PR systems. Our coarse-grained analysis includes an examination of temperature effects, leading to the inference that both hydrophobic and electrostatic interactions drive phase separation in peptide systems.

Changes of cardiac function: cardiac adaptation in patients with hypothyroidism assessed by cardiac magnetic resonance-a meta-analysis.

Objective: The meta-analysis aimed to explore the cardiac adaptation in hypothyroidism patients by cardiac magnetic resonance. Research methods and procedures: Databases including PubMed, Cochrane Library, Embase, CNKI, and Sinomed for clinical studies of hypothyroidism on cardiac function changes. Databases were searched from the earliest data to 15 June 2023. Two authors retrieved studies and evaluated their quality. Review Manager 5.4.1 and Stata18 were used to analyze the data. This study is registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY), 202440114. Results: Six studies were selected for further analysis. Five of them reported differences in cardiac function measures between patients with hypothyroidism and healthy controls, and three studies reported cardiac function parameters after treatment in patients with hypothyroidism. The fixed-effect model combined WMD values for left ventricular ejection fraction (LVEF) had a pooled effect size of -1.98 (95% CI -3.50 to -0.44], P=0.01), implying that LVEF was lower in patients with hypothyroidism than in healthy people. Analysis of heterogeneity found moderate heterogeneity (P = 0.08, I² = 50%). WMD values for stroke volume (SV), cardiac index (CI), left ventricular end-diastolic volume index(LVEDVI), left ventricular end-systolic volume (LESVI), and left ventricular mass index(LVMI) were also analyzed, and pooled effect sizes showed the CI and LVEDVI of patients with hypothyroidism ware significantly decrease (WMD=-0.47, 95% CI [-0.93 to -0.00], P=0.05, WMD=-7.99, 95%CI [-14.01 to -1.96], P=0.009, respectively). Patients with hypothyroidism tended to recover cardiac function after treatment [LVEF (WMD = 6.37, 95%CI [2.05, 10.69], P=0.004), SV (WMD = 7.67, 95%CI [1.61, 13.74], P=0.01), CI (WMD = 0.40, 95%CI [0.01, 0.79], P=0.05)], and there was no difference from the healthy controls. Conclusion: Hypothyroidism could affect cardiac function, although this does not cause significant heart failure. It may be an adaptation of the heart to the hypothyroid state. There was a risk that this adaptation may turn into myocardial damage. Cardiac function could be restored after treatment in patients with hypothyroidism. Aggressive levothyroxine replacement therapy should be used to reverse cardiac function. Systematic review registration: https://inplasy.com, identifier (INPLASY202440114).

Short-Term Supraorbital Nerve Stimulation and Pain Relief for Acute and Subacute Ophthalmic Herpetic Neuralgia: A Randomized Controlled Crossover Trial.

BACKGROUND: Herpes zoster ophthalmicus (HZO) is a kind of refractory disease, and treating it is important for preventing postherpetic neuralgia (PHN). But the evidence surrounding the current treatment options for these conditions is controversial, so exploring reasonable clinical treatment strategies for HZO is necessary. Neuromodulation is an excellent modality for the treatment of various neuropathic pain conditions. This trial was designed to evaluate the effectiveness of short-term supraorbital nerve stimulation (SNS) and the supraorbital nerve block (SNB) for HZO. OBJECTIVES: To determine whether short-term SNS relieves acute and subacute ophthalmic herpetic neuralgia. STUDY DESIGN: This prospective randomized controlled crossover trial compared short-term SNS to SNB. SETTING: The operating room of a pain clinic. METHODS: Patients with acute or subacute ophthalmic herpetic neuralgia were recruited. The patients were randomly assigned to receive either SNS or SNB. The primary outcome being measured was each patient's Visual Analog Scale (VAS) score at 4 weeks. The secondary outcomes under measurement were the proportion of patients who achieved ≥ 50% pain relief, sleep quality, medicine consumption, and adverse events. Crossover after 4 weeks was permitted, and patients were followed up to 12 weeks. RESULTS: Overall, 50 patients were included (n = 25/group). At 4 weeks, the patients who received SNS achieved greater pain relief, as indicated by their significantly different VAS scores from those of the SNB group (mean difference: -1.4 [95% CI, -2.29 to -0.51], P < 0.05). Both groups showed a significant decrease in pain level from the baseline (all P < 0.05). Overall, 72% and 44% of the SNS and SNB patients experienced ≥ 50% pain relief, respectively (OR: 0.31 [95% CI, 0.09 to 0.99], P < 0.05), and 68% and 32% of SNS and SNB patients, respectively, had VAS scores < 3 (OR: 0.22 [95% CI, 0.07 to 0.73], P < 0.05). Compared to the SNB group, the SNS group had better sleep quality, lower ophthalmic neuralgia, a lower proportion of further treatment, and lower analgesic intake. Overall, 18 patients received SNS alone, and 16 patients crossed over from SNB to SNS. The VAS scores, sleep quality, ophthalmic neuralgia, and trend of medicine intake were not significantly different between the groups (all P > 0.05). No serious complications occurred. LIMITATIONS: This study was nonblind. CONCLUSIONS: Short-term SNS is effective for controlling acute or subacute ophthalmic herpetic neuralgia. Combining SNS with SNB yields no additional benefits.

Optical coherence tomography (OCT) - versus angiography-guided strategy for percutaneous coronary intervention: a meta-analysis of randomized trials.

BACKGROUND: Optical coherence tomography (OCT) guidance in percutaneous coronary intervention (PCI) has been shown to improve procedural outcomes. However, evidence supporting its superiority over angiography-guided PCI in terms of clinical outcomes is still emerging and limited. This study aimed to compare the efficacy and safety of OCT-guided PCI versus angiography-guided PCI in patients with coronary artery disease (CAD). METHODS: A systematic search of electronic databases was conducted to identify randomized control trials (RCTs) comparing the clinical outcomes of OCT-guided and angiography-guided PCI in patients with CAD. Clinical endpoints including all-cause mortality, myocardial infarction (MI), target lesion revascularization (TLR), stent thrombosis and major adverse cardiac events (MACE) were assessed. RESULTS: Eleven RCTs, comprising 2,699 patients in the OCT-guided group and 2,968 patients in the angiography-guided group met inclusion criteria. OCT-guided PCI was associated with significantly lower rates of cardiovascular death(RR 0.56; 95%CI: 0.32-0.98; p = 0.04; I2 = 0%), stent thrombosis(RR 0.56; 95%CI: 0.33-0.95; p = 0.03; I2 = 0%), and MACE (RR 0.79; 95%CI: 0.66-0.95; p = 0.01; I2 = 5%). The incidence of all-cause death (RR 0.71; 95%CI: 0.49-1.02; p = 0.06; I2 = 0%), myocardial infarction (RR 0.86; 95%CI: 0.67-1.10; p = 0.22; I2 = 0%) and TLR (RR 0.98; 95%CI: 0.73-1.33; p = 0.91; I2 = 0%) was non-significantly lower in the OCT-guided group. CONCLUSIONS: Among patients undergoing PCI, OCT-guided PCI was associated with lower incidences of cardiovascular death, stent thrombosis and MACE compared to angiography-guided PCI. TRIAL REGISTRATION: PROSPERO registration number: CRD42023484342.

The Bach1/HO-1 pathway regulates oxidative stress and contributes to ferroptosis in doxorubicin-induced cardiomyopathy in H9c2 cells and mice.

Doxorubicin (DOX) is one of the most frequently used chemotherapeutic drugs belonging to the class of anthracyclines. However, the cardiotoxic effects of anthracyclines limit their clinical use. Recent studies have suggested that ferroptosis is the main underlying pathogenetic mechanism of DOX-induced cardiomyopathy (DIC). BTB-and-CNC homology 1 (Bach1) acts as a key role in the regulation of ferroptosis. However, the mechanistic role of Bach1 in DIC remains unclear. Therefore, this study aimed to investigate the underlying mechanistic role of Bach1 in DOX-induced cardiotoxicity using the DIC mice in vivo (DOX at cumulative dose of 20 mg/kg) and the DOX-treated H9c2 cardiomyocytes in vitro (1 µM). Our results show a marked upregulation in the expression of Bach1 in the cardiac tissues of the DOX-treated mice and the DOX-treated cardiomyocytes. However, Bach1-/- mice exhibited reduced lipid peroxidation and less severe cardiomyopathy after DOX treatment. Bach1 knockdown protected against DOX-induced ferroptosis in both in vivo and in vitro models. Ferrostatin-1 (Fer-1), a potent inhibitor of ferroptosis, significantly alleviated DOX-induced cardiac damage. However, the cardioprotective effects of Bach1 knockdown were reversed by pre-treatment with Zinc Protoporphyrin (ZnPP), a selective inhibitor of heme oxygenase-1(HO-1). Taken together, these findings demonstrated that Bach1 promoted oxidative stress and ferroptosis through suppressing the expression of HO-1. Therefore, Bach1 may present as a promising new therapeutic target for the prevention and early intervention of DOX-induced cardiotoxicity.

Methane sink of subterranean space in an integrated atmosphere-soil-cave system.

CH4 serves as an important greenhouse gas, yet limited knowledge is available in global and regional CH4 cycling, particularly in widely distributed karst terrain. In this study, we investigated an upland in Puding Karst Ecosystem Research Station, and explored CH4 concentration and/or flux in atmosphere, soil and cave using a closed static chamber method and an eddy covariance system. Meanwhile, we monitored atmospheric temperature, precipitation, temperature and wind velocity in the cave entrance. The results demonstrated that atmospheric CH4 and actual soil CH4 fluxes in the source area of eddy covariance system were -0.19 ± 8.64 nmols-1m-2 and -0.16 nmols-1m-2 respectively. The CH4 concentrations in Shawan Cave exhibited 10 âˆ¼ 100-fold lower than that of the external atmosphere. CH4 oxidation rate dominated by methane-oxidizing bacteria was 1.98 nmols-1m-2 in Shawan Cave when it combined with temperature difference between cave and external atmosphere. Therefore, CH4 sink in global karst subterranean spaces was estimated at 106.2 Tg CH4 yr-1. We supplemented an understanding of CH4 cycling paths and fluxes in karst terrain, as well as CH4 sinks in karst subterranean space. Further works require to establish a karst ecosystem observation network to conduct long-term integrated studies on CH4 fluxes regarding atmosphere, soils, plants and caves.

Design of ultrahigh-Q silicon microring resonators based on free-form curves.

A design method for ultrahigh-Q microring resonators (MRRs) based on Bezier free-form curves was proposed and demonstrated. An MRR consisting of a specially designed 180° waveguide bend, a directional coupler, and two low-loss multi-mode strip waveguides was designed. The free-form curves were used to increase the degree of freedom in the design, shaping the waveguide bend with a gradient width and curvature. This design effectively reduced the propagation loss caused by the roughness of waveguide sidewalls and the mode mismatch loss caused by the excitation of high order modes. The small effective radius of only 20µm enabled the MRR to have a large free spectral range (FSR) and a compact and flexible structure. The MRR was manufactured using a standard process provided by foundry and measured to have an ultrahigh loaded Q factor of 1.86 × 106 and a FSR of about 1 nm.

A new technique of autologous bone grafting for open-wedge high tibial osteotomy.

Purpose: This study aimed to demonstrate the application of orthotopic bone flap transplantation with a fibula transplantation (OBFT-FT) in open-wedge high tibial osteotomy (OW-HTO) and to assess the effect of OBFT-FT on gap healing. Patients and methods: From January to July 2020, 18 patients who underwent OW-HTO with OBFT-FT were reviewed for this study. Demographics, postoperative complications, and radiological and clinical outcomes of patients were collected. Finally, the clinical outcomes of patients were analyzed. Results: A total of 14 patients were included in this study. The average age and body mass index were 59.6 ± 9.2 years and 28.1 ± 4.5 kg/m2, respectively. The average correction angle and gap width were 9.5 ± 1.8° and 10.2 ± 2.7 mm, respectively. The rates of radiological gap healing at sixth week, third month, and sixth month were 42.9%, 85.7%, and 100%, respectively. The mean Lysholm score, International Knee Documentation Committee score, and visual analog scale scores at sixth-month follow-up were significantly better than the preoperative scores (p < 0.001, p < 0.001, p = 0.001, respectively). And, no delayed union or non-union, collapse, loss of correction, or surgical site infection were found. Conclusions: As a new technique for autologous bone graft, the OBFT-FT could be successfully applied in the treatment of gap healing after OW-HTO, and excellent radiological and clinical outcomes could be seen on patients' short-term follow-up.

Electroreduction of unactivated alkenes using water as hydrogen source.

Herein, we report an electroreduction of unactivated alkyl alkenes enabled by [Fe]-H, which is provided through the combination of anodic iron salts and the silane generated in situ via cathodic reduction, using H2O as an H-source. The catalytic amounts of Si-additive work as an H-carrier from H2O to generate a highly active silane species in situ under continuous electrochemical conditions. This approach shows a broad substrate scope and good functional group compatibility. In addition to hydrogenation, the use of D2O instead of H2O provides the desired deuterated products in good yields with excellent D-incorporation (up to >99%). Further late-stage hydrogenation of complex molecules and drug derivatives demonstrate potential application in the pharmaceutical industry. Mechanistic studies are performed and provide support for the proposed mechanistic pathway.

Agaro-oligosaccharides mitigate deoxynivalenol-induced intestinal inflammation by regulating gut microbiota and enhancing intestinal barrier function in mice.

Agarose-derived agaro-oligosaccharides (AgaroS) have been extensively studied in terms of structures and bioactivities; they reportedly possess antioxidant and anti-inflammatory activities that maintain intestinal homeostasis and host health. However, the protective effects of AgaroS on deoxynivalenol (DON)-induced intestinal dysfunction remain unclear. We investigated the effects of AgaroS on DON-induced intestinal dysfunction in mice and explored the underlying protective mechanisms. In total, 32 mice were randomly allocated to four treatments (n = 8 each) for 28 days. From day 1 to day 21, the control (CON) and DON groups received oral phosphate-buffered saline (200 µL per day); the AgaroS and AgaroS + DON groups received 200 mg AgaroS per kg body weight once daily by orogastric gavage. Experimental intestinal injury was induced by adding DON (4.8 mg per kg body weight) via gavage from day 21 to day 28. Phosphate-buffered saline was administered once daily by gavage in the CON and AgaroS groups. Herein, AgaroS supplementation led to a higher final body weight and smaller body weight loss and a lower concentration of plasma inflammatory cytokines, compared with the DON group. The DON group showed a significantly reduced ileal villus height and villus height/crypt depth, compared with the CON and AgaroS + DON groups. However, AgaroS supplementation improved DON-induced intestinal injury in mice. Compared with the DON group, ileal and colonic protein expression levels of claudin, occludin, Ki67, and mucin2 were significantly higher in the AgaroS supplementation group. Colonic levels of the anti-inflammatory cytokine IL-1ß tended to be higher in the DON group than in the AgaroS + DON group. AgaroS altered the gut microbiota composition, accompanied by increased production of short-chain fatty acids in mice. In conclusion, our findings highlight a promising anti-mycotoxin approach whereby AgaroS alleviate DON-induced intestinal inflammation by modulating intestinal barrier functional integrity and gut microbiota in mice.

Peak ground acceleration prediction for on-site earthquake early warning with deep learning.

Rapid and accurate prediction of peak ground acceleration (PGA) is an important basis for determining seismic damage through on-site earthquake early warning (EEW). The current on-site EEW uses the feature parameters of the first arrival P-wave to predict PGA, but the selection of these feature parameters is limited by human experience, which limits the accuracy and timeliness of predicting peak ground acceleration (PGA). Therefore, an end-to-end deep learning model is proposed for predicting PGA (DLPGA) based on convolutional neural networks (CNNs). In DLPGA, the vertical initial arrival 3-6 s seismic wave from a single station is used as input, and PGA is used as output. Features are automatically extracted through a multilayer CNN to achieve rapid PGA prediction. The DLPGA is trained, verified, and tested using Japanese seismic records. It is shown that compared to the widely used peak displacement (Pd) method, the correlation coefficient of DLPGA for predicting PGA has increased by 12-23%, the standard deviation of error has decreased by 22-25%, and the error mean has decreased by 6.92-19.66% with the initial 3-6 s seismic waves. In particular, the accuracy of DLPGA for predicting PGA with the initial 3 s seismic wave is better than that of Pd for predicting PGA with the initial 6 s seismic wave. In addition, using the generalization test of Chilean seismic records, it is found that DLPGA has better generalization ability than Pd, and the accuracy of distinguishing ground motion destructiveness is improved by 35-150%. These results confirm that DLPGA has significant accuracy and timeliness advantages over artificially defined feature parameters in predicting PGA, which can greatly improve the effect of on-site EEW in judging the destructiveness of ground motion.

One-pot solvothermal synthesis of Cu-Fe-MOF for efficiently activating peroxymonosulfate to degrade organic pollutants in water:Effect of electron shuttle.

Persulfate-based advanced oxidation processes (PS-AOPs) show a bright prospect in sewage purification. The development of efficient catalysts with simple preparation process and eco-friendliness is the key for their applying in practical water treatment. Herein, a bimetallic Cu-Fe metal organic framework (MOF) was simply synthesized by using one-pot solvothermal methods and employed for activating peroxymonosulfate (PMS) to degrade organic pollutants in water. The Cu-Fe-MOF/PMS exhibited excellent degradation efficiencies (over 95% in 30 min) for a variety of pollutants, including phenol, bisphenol A, 2,4-dichlorophenol, methyl blue, rhodamine B, tetracycline and sulfamethoxazole. The degradation efficiency was impacted by dosages of Cu-Fe-MOF, PMS concentrations, reaction temperature, solution pH and anionic species. Phenol could be efficiently decomposed in a wide pH range of 5-9, with the highest degradation and mineralization efficiency of nearly 100% and 70%, respectively. Free radicals and non-free radicals participated in degrading of phenol at the same time, with dominantly free radical process, because sulfate radicals (SO4·-) and hydroxyl radicals (·OH) were the primary active substances by contribution calculation. Cu-Fe-MOF was acted as electron shuttle between molecules of phenol and PMS, and the cooperation effect of Fe and Cu on the Cu-Fe-MOF promoted the electron transfer, achieving the high degradation efficiency of phenol. Thus, Cu-Fe-MOF is an ideal catalyst for activating PMS, which is conducive to promote the applying of catalyst-activated PMS processes for practical wastewater treatments.

Development of a Multifaceted Perspective for Systematic Analysis, Assessment, and Performance for Environmental Standards of Contaminated Sites.

Contaminated soil and groundwater can pose significant risks to human health and ecological environments, making the remediation of contaminated sites a pressing and sustained challenge. It is significant to identify key performance indicators and advance environmental management standards of contaminated sites. The traditional study currently focuses on the inflexible collection of related files and displays configurable limitations regarding integrated assessment and in-depth analysis of published standards. In addition, there is a relative lack of research focusing on the analysis of different types of standard documents. Herein, we introduce a cross-systematic retrospective and review for the development of standards of the contaminated sites, including the comprehensive framework, multifaceted analysis, and improved suggestion of soil and groundwater standards related to the environment. The classification and structural characteristics of different types of files are systematically analyzed of over 300 national, trade, local, and group standards for the contaminated sites. It exhibits that trade standards are the main types and testing methods are the important format within numerical considerations of soil standards. The guide standard serves as a crucial component in environmental management for investigating, assessing, and remediating of contaminated sites. Future improvement plans and development directions are proposed for advancing robust technical support for effective soil contamination prevention and control. This multidimensional analysis and the accompanying suggestions can provide improved guidance for Chinese environmental management of contaminated sites and sparkle the application of standards in a wide range of countries.

The effect of cave ventilation on carbon and oxygen isotopic fractionation between calcite and drip water.

Rapid CO2 degassing and calcite precipitation driven by cave ventilation influence the speleothem δ18O and δ13C. However, the drivers of cave ventilation are not completely understood due to the lack of monitoring of multiple environmental factors. Furthermore, the understanding of isotope fractionation caused by the dissolution of speleothem in undersaturated drip water is limited during the cave air stagnation. In this study, we displayed four years of cave microenvironment monitoring in Shawan Cave, Southwestern China, and analyzed the δ13CDIC and δ18O of drip water, and calcite precipitation δ18O and δ13C. The results show that the ventilation process is attributed to buoyancy airflow between external atmosphere, fissure air, and cave air. This causes that the higher (lower) cave air pCO2 in the summer (winter) is associated with upward airflow mode (downward airflow mode). Furthermore, cave ventilation could control the isotopic fractionation. Specifically, when cave air pCO2 is lower, the carbon isotopic disequilibrium between calcite and dissolved inorganic carbon (DIC) is controlled by the degassing of CO2 associated with calcite precipitation. The disequilibrium fractionation in carbon isotopes is less pronounced at slower drip-rate sites. The oxygen isotope fractionation between calcite and the drip water is found to be close to equilibrium. However, the high cave air pCO2 (exceeding 10,000 ppm) may result in drip water undersaturation to drive the dissolution of speleothem calcite. The δ18O values of drip water are pulled away from their original values to disequilibrate to the calcite because the exchange time of oxygen in the dissolved carbonates with the oxygen in the water is sufficiently long. Hence, the dissolution of speleothems may be a new mechanism to explain the oxygen isotopic disequilibrium between the calcite and drip water during the cave air stagnation. The carbon isotope fractionation between calcite and drip water is close to equilibrium.

Introduction and An Analysis of Inter- and Intra-observer Validity to the Classification of Hoffa-Like Tibial Plateau Fractures.

OBJECTIVE: The posterior coronal shearing fractures of the tibial plateau are rare and can be easily missed or ignored. Our team defined these fractures as Hoffa-like fracture of the tibial plateau and conducted a series of studies. The aim of this study is to introduce the characteristics of the Hoffa-like fracture of the tibial plateau, propose a new classification system and evaluate its validity. METHODS: Sixty-one patients with Hoffa-like fractures of the tibial plateau were treated in five trauma centers (I-III) from 2017 to 2020. A new classification system was developed based on the morphological fracture patterns in CT and radiographic of the first 30 cases. Ten cases of suspected tibial plateau Hoffa-like fractures were supplemented additionally to the 61 cases to increase the accuracy. CT and radiographic images of the 71 cases were reviewed independently by four reviewers on two separate occasions and classified according to the new classification system. Cohen's kappa coefficient (κ) was used to analyze the reliability on separate observers at the same time and to analyze the classification made by same observer at different times (intra-observer), which measures inter-observer and intra-observer agreements. RESULTS: Out of the 61 patients, 46 (75.4%) isolated coronal fractures involving the medial condyle of tibial plateaus and 53 (86.9%) combined with intercondylar spine fractures. The κ-values were calculated for the new classification system (mean κ = 0.74 inter-observer, mean κ = 0.79 intra-observer, indicating substantial agreement). CONCLUSION: The novel classification lends insight into fracture morphology of the tibial plateau Hoffa-like fractures, has good inter- and intra-observer validity, and it aids in treatment.

Aluminum-incorporation activates vanadium carbide with electron-rich carbon sites for efficient pH-universal hydrogen evolution reaction.

Vanadium carbide (VC) is the greatest potential hydrogen evolution reaction (HER) catalyst because of its platinum-like property and abundant earth reserves. However, it exhibits insufficient catalytic performance due to the unfavorable interaction of reaction intermediates with catalysts. In this work, using NH4VO3 as the main raw material, the flow ratio of CH4 to Ar was accurately controlled, and a non-transition metal Al-doped into VC (100) nano-flowers with carbon hybrids on nickel foams (Al-VC@C/NF) was prepared for the first time as a high-efficiency HER catalyst by chemical vapor carbonization. The overpotential of Al-VC@C/NF catalysts in 0.5 M H2SO4 and 1 M KOH at a current density of 10 mA cm-2 are only 58 mV and 97 mV, respectively, which are the best HER performance among non-noble metal vanadium carbide based catalysts. Simultaneously, Al-VC@C/NF exhibits small Tafel slope (45 mV dec-1 and 73 mV dec-1) and excellent stability in acidic and alkaline media. Theoretical calculations demonstrate that doped Al atoms can induce electron redistribution on the vanadium carbide surface to form electron-rich carbon sites, which significantly reduces the energy barrier during the HER process. This work provides a new tactic to modulate vanadium-based carbons as efficient HER catalysts through non-transition metal doping.