Dose-Response Study of Phenylephrine for Preventing Spinal-Induced Hypotension During Cesarean Delivery with Combined Spinal-Epidural Anesthesia Under the Effect of Prophylactic Intravenous Ondansetron.

Background: Ondansetron reduces the median effective dose (ED50) of prophylactic phenylephrine to prevent spinal-induced hypotension (SIH) during cesarean delivery. However, the exact dose response of phenylephrine in combination with prophylactic ondansetron for preventing SIH is unknown. Therefore, this study aimed to determine the dose-response of phenylephrine to prevent SIH in cesarean delivery when 4 mg of ondansetron was used as a preventive method. Methods: A total of 80 parturients were enrolled and divided randomly into four groups (n = 20 in each group) who received either 0.2, 0.3, 0.4, or 0.5 µg/kg/min of prophylactic phenylephrine. Ten minutes before the initiation of spinal induction, 4 mg prophylactic ondansetron was administered. The effective dose of prophylactic phenylephrine was defined as the dose required to prevent hypotension after the period of intrathecal injection and up to neonatal delivery. The ED50 and ED90 of prophylactic phenylephrine and 95% confidence intervals (95% CI) were calculated using probit analysis. Results: The ED50 and ED90 for prophylactic phenylephrine to prevent SIH were 0.25 (95% CI, 0.15 to 0.30), and 0.45 (95% CI, 0.39 to 0.59) µg/kg/min, respectively. No significant differences were observed in the side effects and neonatal outcomes between the four groups. Conclusion: The administration of 4 mg of prophylactic ondansetron was associated with an ED50 of 0.25 (95% CI, 0.15~0.30) and ED90 of 0.45 (95% CI, 0.39~0.59) µg/kg/min for phenylephrine to prevent SIH.

Probucol mitigates high-fat diet-induced cognitive and social impairments by regulating brain redox and insulin resistance.

Probucol has been utilized as a cholesterol-lowering drug with antioxidative properties. However, the impact and fundamental mechanisms of probucol in obesity-related cognitive decline are unclear. In this study, male C57BL/6J mice were allocated to a normal chow diet (NCD) group or a high-fat diet (HFD) group, followed by administration of probucol to half of the mice on the HFD regimen. Subsequently, the mice were subjected to a series of behavioral assessments, alongside the measurement of metabolic and redox parameters. Notably, probucol treatment effectively alleviates cognitive and social impairments induced by HFD in mice, while exhibiting no discernible influence on mood-related behaviors. Notably, the beneficial effects of probucol arise independently of rectifying obesity or restoring systemic glucose and lipid homeostasis, as evidenced by the lack of changes in body weight, serum cholesterol levels, blood glucose, hyperinsulinemia, systemic insulin resistance, and oxidative stress. Instead, probucol could regulate the levels of nitric oxide and superoxide-generating proteins, and it could specifically alleviate HFD-induced hippocampal insulin resistance. These findings shed light on the potential role of probucol in modulating obesity-related cognitive decline and urge reevaluation of the underlying mechanisms by which probucol exerts its beneficial effects.

A comprehensive study on machine learning models combining with oversampling for bronchopulmonary dysplasia-associated pulmonary hypertension in very preterm infants.

BACKGROUND: Bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) remains a devastating clinical complication seriously affecting the therapeutic outcome of preterm infants. Hence, early prevention and timely diagnosis prior to pathological change is the key to reducing morbidity and improving prognosis. Our primary objective is to utilize machine learning techniques to build predictive models that could accurately identify BPD infants at risk of developing PH. METHODS: The data utilized in this study were collected from neonatology departments of four tertiary-level hospitals in China. To address the issue of imbalanced data, oversampling algorithms synthetic minority over-sampling technique (SMOTE) was applied to improve the model. RESULTS: Seven hundred sixty one clinical records were collected in our study. Following data pre-processing and feature selection, 5 of the 46 features were used to build models, including duration of invasive respiratory support (day), the severity of BPD, ventilator-associated pneumonia, pulmonary hemorrhage, and early-onset PH. Four machine learning models were applied to predictive learning, and after comprehensive selection a model was ultimately selected. The model achieved 93.8% sensitivity, 85.0% accuracy, and 0.933 AUC. A score of the logistic regression formula greater than 0 was identified as a warning sign of BPD-PH. CONCLUSIONS: We comprehensively compared different machine learning models and ultimately obtained a good prognosis model which was sufficient to support pediatric clinicians to make early diagnosis and formulate a better treatment plan for pediatric patients with BPD-PH.

Development and external validation of a transfer learning-based system for the pathological diagnosis of colorectal cancer: a large emulated prospective study.

Background: The progress in Colorectal cancer (CRC) screening and management has resulted in an unprecedented caseload for histopathological diagnosis. While artificial intelligence (AI) presents a potential solution, the predominant emphasis on slide-level aggregation performance without thorough verification of cancer in each location, impedes both explainability and transparency. Effectively addressing these challenges is crucial to ensuring the reliability and efficacy of AI in histology applications. Method: In this study, we created an innovative AI algorithm using transfer learning from a polyp segmentation model in endoscopy. The algorithm precisely localized CRC targets within 0.25 mm² grids from whole slide imaging (WSI). We assessed the CRC detection capabilities at this fine granularity and examined the influence of AI on the diagnostic behavior of pathologists. The evaluation utilized an extensive dataset comprising 858 consecutive patient cases with 1418 WSIs obtained from an external center. Results: Our results underscore a notable sensitivity of 90.25% and specificity of 96.60% at the grid level, accompanied by a commendable area under the curve (AUC) of 0.962. This translates to an impressive 99.39% sensitivity at the slide level, coupled with a negative likelihood ratio of <0.01, signifying the dependability of the AI system to preclude diagnostic considerations. The positive likelihood ratio of 26.54, surpassing 10 at the grid level, underscores the imperative for meticulous scrutiny of any AI-generated highlights. Consequently, all four participating pathologists demonstrated statistically significant diagnostic improvements with AI assistance. Conclusion: Our transfer learning approach has successfully yielded an algorithm that can be validated for CRC histological localizations in whole slide imaging. The outcome advocates for the integration of the AI system into histopathological diagnosis, serving either as a diagnostic exclusion application or a computer-aided detection (CADe) tool. This integration has the potential to alleviate the workload of pathologists and ultimately benefit patients.

A case of acute lung injury in a peripheral blood stem cell donor mobilized with pegylated recombinant human granulocyte colony-stimulating factor.

Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) has been introduced for the mobilization of peripheral blood stem cells (PBSCs). However, no cases of acute lung injury (ALI) in healthy donors have been reported, and the underlying mechanisms remain poorly understood. We first reported a case of ALI caused by PEG-rhG-CSF in a healthy Chinese donor, characterized by hemoptysis, hypoxemia, and patchy shadows. Ultimately, hormone administration, planned PBSC collection, leukocyte debridement, and planned PBSC collection resulted in active control of the donor's ALI. The donor's symptoms improved without any adverse effects, and the PBSC collection proceeded without incident. Over time, the lung lesion was gradually absorbed and eventually returned to normal. PEG-rhG-CSF may contribute to ALI in healthy donors via mechanisms involving neutrophil aggregation, adhesion, and the release of inflammatory mediators in the lung. This case report examines the clinical manifestations, treatment, and mechanism of lung injury induced by PEG-rhG-CSF-mobilized PBSCs.

Joint association of TyG index and high sensitivity C-reactive protein with cardiovascular disease: a national cohort study.

BACKGROUND: Both the triglyceride-glucose (TyG) index, as a surrogate marker of insulin resistance, and systemic inflammation are predictors of cardiovascular diseases; however, little is known about the coexposures and relative contributions of TyG index and inflammation to cardiovascular diseases. Using the nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS), we conducted longitudinal analyses to evaluate the joint and mutual associations of the TyG index and high-sensitivity C-reactive protein (hsCRP) with cardiovascular events in middle-aged and older Chinese population. METHODS: This study comprised 8 658 participants aged at least 45 years from the CHARLS 2011 who are free of cardiovascular diseases at baseline. The TyG index was calculated as Ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2]. Cardiovascular events were defined as the presence of physician-diagnosed heart disease and/or stroke followed until 2018.We performed adjusted Cox proportional hazards regression and mediation analyses. RESULTS: The mean age of the participants was 58.6 ± 9.0 years, and 3988 (46.1%) were females. During a maximum follow-up of 7.0 years, 2606 (30.1%) people developed cardiovascular diseases, including 2012 (23.2%) cases of heart diseases and 848 (9.8%) cases of stroke. Compared with people with a lower TyG index (< 8.6 [median level]) and hsCRP < 1 mg/L, those concurrently with a higher TyG and hsCRP had the highest risk of overall cardiovascular disease (adjusted hazard ratio [aHR], 1.300; 95% CI 1.155-1.462), coronary heart disease (aHR, 1.294; 95% CI 1.130-1.481) and stroke (aHR, 1.333; 95% CI 1.093-1.628), which were predominant among those aged 70 years or below. High hsCRP significantly mediated 13.4% of the association between the TyG index and cardiovascular disease, while TyG simultaneously mediated 7.9% of the association between hsCRP and cardiovascular risk. CONCLUSIONS: The findings highlight the coexposure effects and mutual mediation between the TyG index and hsCRP on cardiovascular diseases. Joint assessments of the TyG index and hsCRP should be underlined for the residual risk stratification and primary prevention of cardiovascular diseases, especially for middle-aged adults.

Crystal structure of the iron-sulfur cluster transfer protein ApbC from Escherichia coli.

Iron-sulfur (Fe-S) clusters are ubiquitous and are necessary to sustain basic life processes. The intracellular Fe-S clusters do not form spontaneously and many proteins are required for their biosynthesis and delivery. The bacterial P-loop NTPase family protein ApbC participates in Fe-S cluster assembly and transfers the cluster into apoproteins, with the Walker A motif and CxxC motif being essential for functionality of ApbC in Fe-S protein biogenesis. However, the structural basis underlying the ApbC activity and the motifs' role remains unclear. Here, we report the crystal structure of Escherichia coli ApbC at 2.8 Å resolution. The dimeric structure is in a W shape and the active site is located in the 2-fold center. The function of the motifs can be annotated by structural analyses. ApbC has an additional N-terminal domain that differs from other P-loop NTPases, possibly conferring its inherent specificity in vivo.

Multi-Instance Learning for Vocal Fold Leukoplakia Diagnosis Using White Light and Narrow-Band Imaging: A Multicenter Study.

OBJECTIVES: Vocal fold leukoplakia (VFL) is a precancerous lesion of laryngeal cancer, and its endoscopic diagnosis poses challenges. We aim to develop an artificial intelligence (AI) model using white light imaging (WLI) and narrow-band imaging (NBI) to distinguish benign from malignant VFL. METHODS: A total of 7057 images from 426 patients were used for model development and internal validation. Additionally, 1617 images from two other hospitals were used for model external validation. Modeling learning based on WLI and NBI modalities was conducted using deep learning combined with a multi-instance learning approach (MIL). Furthermore, 50 prospectively collected videos were used to evaluate real-time model performance. A human-machine comparison involving 100 patients and 12 laryngologists assessed the real-world effectiveness of the model. RESULTS: The model achieved the highest area under the receiver operating characteristic curve (AUC) values of 0.868 and 0.884 in the internal and external validation sets, respectively. AUC in the video validation set was 0.825 (95% CI: 0.704-0.946). In the human-machine comparison, AI significantly improved AUC and accuracy for all laryngologists (p < 0.05). With the assistance of AI, the diagnostic abilities and consistency of all laryngologists improved. CONCLUSIONS: Our multicenter study developed an effective AI model using MIL and fusion of WLI and NBI images for VFL diagnosis, particularly aiding junior laryngologists. However, further optimization and validation are necessary to fully assess its potential impact in clinical settings. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

The key role of muscle spindles in the pathogenesis of myofascial trigger points according to ramp-and-hold stretch and drug intervention in a rat model.

This study investigated whether abnormal peak inversion spontaneous potentials (PISPs) recorded at resting myofascial trigger points (MTrPs) stem from the discharge of muscle spindles. Forty-eight male Sprague-Dawley rats were randomly divided into six groups. Five groups underwent MTrP modeling intervention, whereas one group did not receive intervention and was duly designated as the blank control. After model construction, five rat models were randomly subjected to ramp-and-hold stretch tests, succinylcholine injection, eperisone hydrochloride injection, saline injection, and blank drug intervention. By contrast, the rats in the blank control group were subjected to ramp-and-hold stretch tests as a control. Frequencies and amplitudes of PISPs were recorded pre- and post-interventions and compared with those of the blank group. Stretch tests showed that the depolarization time and amplitude of PISPs ranged from 0.4 ms to 0.9 ms and from 80 uV to 140 µV, respectively. However, no PISPs were observed in the control rats. The frequency of PISPs in the ramp and hold phases and the first second after the hold phase was higher than that before stretching (p < 0.01). Succinylcholine and eperisone exerted excitatory and inhibitory effects on PISPs, respectively. In the group injected with 0.9% saline, no considerable differences of the PISPs were observed during the entire observation period. In conclusion, PISPs recorded at resting MTrPs are closely related to muscle spindles. The formation of MTrPs may be an important factor that regulate dysfunctional muscle spindles.

Carbonized polymer dots-based molecular imprinting: An adsorbent with enhanced selectivity for highly efficient recognition and removal of ceftiofur sodium from complex samples.

Highly selective removal of residual cephalosporin antibiotics from complex systems is crucial for human health and ecological environment protection. Herein, a newly molecularly imprinted polymer adsorbent (CPDs-NH2@MIP) with enhanced selectivity for ceftiofur sodium (CTFS) was developed by using the special carbonized polymer dots (CPDs-NH2) as functional monomer. The CPDs-NH2 has a nano-spherical structure and functionalized groups (CC, -NH2) via the incomplete carbonization polymerization of citric acid, acrylamide and ethylenediamine, which can accurately interact with CTFS by overcoming steric hindrance, resulting in more precisely imprinted sites and reducing non-imprinted regions in MIP. The presented CPDs-NH2@MIP exhibited excellent adsorption capacity for CTFS (68.62 mg g-1), achieving equilibrium within 10 min, and highly selectivity in mixed solution containing five coexisting substances, with an imprinted factor (5.61). Compared with commercial adsorbents and MIPs prepared with traditional chain functional monomers, the CPDs-NH2@MIP showed significant advantage in selective recognition and separation of target. Analysis of microstructure and mechanism proved that usage of the spherical functional monomer generated precise imprinting sites and dense structure in CPDs-NH2@MIP, which effectively enhanced the selectivity in complex system combined with hydrogen bonding interaction. The idea of designing and using spherical functional monomer will promote the practicality of molecularly imprinted polymer adsorbents.

A clinical nomogram for predicting occult lymph node metastasis in patients with non-small cell lung cancer≤2 cm.

OBJECTIVES: Sublobar resection has been shown to be feasible for non-small cell lung cancers less than 2 cm in size based on several prospective studies. However, the prognosis of clinical N0 patients who experience an N-stage upgrade after surgery (known as occult lymph node metastasis) may be worse. The ability of predict occult lymph node metastasis in patients eligible for sublobar resection remains a controversial issue. METHODS: Patients with non-small cell lung cancer ≤2 cm in diameter and containing a solid component who underwent surgical treatment at the Affiliated Hospital of Qingdao University were retrospectively enrolled, and 1:1 case matching was performed. The risk factors were identified through logistic regression analyses and theoretical criteria, followed by the development of a nomogram that was evaluated using 200 iterations of 10-fold cross-validation. RESULTS: After case matching, 130 pairs of patients were selected for modelling. According to the multivariable logistic regression analysis, the carcinoembryonic antigen level, consolidation tumour ratio, mean computed tomography number and tumour margin were included in the nomogram. The cross-validated average area under the receiver operating characteristic curve was found to be 0.86. Furthermore, calibration curve and decision curve analyses demonstrated the excellent predictive accuracy and clinical utility of the nomogram respectively. CONCLUSIONS: By utilizing accessible characteristics, we developed a nomogram that predicts the probability of occult lymph node metastasis in patients with NSCLC ≤2 cm with a solid component. Risk stratification with this nomogram could aid in surgical method decision-making.

Gastroretentive Raft Forming System for Enhancing Therapeutic Effect of Drug-Loaded Hollow Mesoporous Silica on Gastric Ulcers.

Gastric ulcers are characterized by damage to the stomach lining and are often triggered by substances such as ethanol and non-steroidal anti-inflammatory drugs. Patchouli alcohol (PA) has demonstrated effectiveness in treating gastric ulcers through antioxidative and anti-inflammatory effects. However, the water insolubility of PA and rapid gastric emptying cause low drug concentration and poor absorption in the stomach, resulting in limited treatment efficacy of PA. This study develops an oral gastroretentive raft forming system (GRFDDS) containing the aminated hollow mesoporous silica nanoparticles (NH2-HMSN) for PA delivery. The application of NH2-HMSN can enhance PA-loading capacity and water dispersibility, promoting bio-adhesion to the gastric mucosa and sustained drug release. The incorporation of PA-loaded NH2-HMSN (NH2-HMSN-PA) into GRFDDS can facilitate gastric drug retention and achieve long action, thereby improving therapeutic effects. The results reveal that NH2-HMSN-PA protects the gastric mucosa damage by inhibiting NLRP3-mediated pyroptosis. The GRFDDS, optimized through orthogonal design, demonstrates the gastric retention capacity and sustained drug release, exhibiting significant therapy efficacy in an ethanol-induced acute gastric ulcers model and an aspirin-induced chronic gastric ulcers model through antioxidation, anti-pyroptosis, and anti-inflammation. This study provides a potential strategy for enhancing druggability of insoluble natural compounds and therapeutic management of gastric ulcers.

Habitat differentiation and environmental adaptability contribute to leaf size variations globally in C3 and C4 grasses.

The grass family (Poaceae) dominates ~43 % of Earth's land area and contributes 33 % of terrestrial primary productivity that is critical to naturally regulating atmosphere CO2 concentration and global climate change. Currently grasses comprise ~11,780 species and ~50 % of them (~6000 species) utilize C4 photosynthetic pathway. Generally, grass species have smaller leaves under colder and drier environments, but it is unclear whether the primary drivers of leaf size differ between C3 and C4 grasses on a global scale. Here, we analyzed 33 environmental variables, such as latitude, elevation, mean annual temperature, mean annual precipitation, and solar radiation etc., through a comparatively comprehensive database of ~3.0 million occurrence records from 1380 C3 and 978 C4 grass species (2358 species in total). Results from this study confirm that C4 grasses have occupied habitats with lower latitudes and elevations, characterized by warmer, sunnier, drier and less fertile environmental conditions. Grass leaf size correlates positively with mean annual temperature and precipitation as expected. Our results also demonstrate that the mean temperature of the wettest quarter of the year is the primary control for C3 leaf size, whereas C4 leaf size is negatively correlated with the difference between summer and winter temperatures. For C4 grasses, phylogeny exerts a significant effect on leaf size but is less important than environmental factors. Our findings highlight the importance of evolutionarily contrasting variations in leaf size between C3 and C4 grasses for shaping their geographical distribution and habitat suitability at the global scale.

Linarin Ameliorates Restenosis After Vascular Injury in Type 2 Diabetes Mellitus via Regulating ADAM10-Mediated Notch Signaling Pathway.

Vascular lesions frequently arise as complication in patients diagnosed with diabetes mellitus (DM). Presently, percutaneous coronary intervention (PCI) and antithrombotic therapy serve as primary treatments. However, in-stent restenosis persists as a challenging clinical issue following PCI, lacking sustained and effective treatment. Linarin (LN) exhibits diverse pharmacological activities and is regarded as a potential drug for treating various diseases, including DM. But its specific role in restenosis after vascular injury in DM patients remains unclear. A rat model of diabetes-related restenosis was established to evaluate the role of LN on neointimal hyperplasia. Vascular smooth muscle cells (VSMCs) stimulated by high glucose (HG, 30 mM) underwent LN treatment. Additionally, an overexpression plasmid of A disintegrin and metalloproteinases (ADAM10) was constructed to transfect VSMCs. We employed CCK-8, Brdu, wound-healing scratch, and transwell migration assays to evaluate the proliferation and migration of VSMCs. Furthermore, western blot and immunofluorescence assays were utilized to investigate the expressions of ADAM10 and the downstream Notch signaling pathway in vivo and in vitro models. LN notably alleviated intimal hyperplasia after vascular injury in DM rats and reduced the protein expression of ADAM10, alongside its downstream Notch1 signaling pathway-related proteins (Notch1, NICD and Hes1) in rat carotid artery tissues. LN effectively suppressed the proliferation and migration of VSMCs induced by HG, downregulating the protein expression of ADAM10, Notch1, NICD and Hes1. Moreover, our findings indicated that ADAM10 overexpression significantly reversed LN's effects on proliferation, migration, and the expression of Notch1 signaling pathway-related proteins in HG-treated VSMCs. LN demonstrates potential therapeutic efficacy in addressing restenosis after diabetic-related vascular injury, with the ADAM10 mediated Notch signaling pathway playing a pivotal role.

Causal Association Between Diabetes, Body Mass Index and Lichen Sclerosus: A Bidirectional Two-Sample Mendelian Randomization Analysis.

Background: Previous observational studies have found that lichen sclerosus (LS) is associated with metabolic statuses, such as diabetes mellitus (DM) and body mass index (BMI). However, there are also some studies showing that LS is not related to DM and BMI. The mechanism behind observational results is still unclear. Therefore, the causality of this relationship remains unknown. In this study, a bidirectional two-sample Mendelian randomization (MR) was conducted to investigate the correlation between DM, BMI, and LS. Methods: The instrumental variables related to DM (including type 1 and type 2 diabetes), and BMI were identified from genome-wide association studies (GWAS) and a GWAS meta-analysis. The GWAS data for LS was from obtained the eighth edition of the FinnGen biological database released in 2022. Inverse variance weighted (IVW), weighted median, and MR-Egger methods were used to conduct a bidirectional two-sample MR analysis. Thereafter, the heterogeneity and horizontal pleiotropy were examined to determine whether the results were affected by a single-nucleotide polymorphism (SNP). Results: We found a lack of evidence for the causal association of DM, and BMI on LS in inverse variance weighted (type 1 diabetes, OR=0.97, 95% CI=0.91-1.04, p=0.429; type 2 diabetes, OR=0.91, 95% CI=0.82-1.00, p=0.0511; BMI, OR=0.92, 95% CI=0.73-1.15, p=0.4554). In the other direction, the results also showed that LS had no significant causal effect on DM and BMI. Conclusion: This MR analysis demonstrated no significant causal relationship between DM and BMI with LS in both directions, which contradicts previous observational studies reporting a positive association. Potential confounding factors may contribute to previously observed associations, and further research is necessary.

Role of tcaA, a potential target as a ceftobiprole resistance breaker, in MRSA ß-lactam resistance.

OBJECTIVES: Using a random forest algorithm, we previously found that teicoplanin-associated gene A (tcaA) might play a role in resistance of methicillin-resistant Staphylococcus aureus (MRSA) to ß-lactams, which we have investigated further here. METHODS: Representative MRSA strains of prevalent clones were selected to identify the role of tcaA in the MRSA response to ß-lactams. tcaA genes were deleted by homologous recombination in the selected MRSA strains, and antibiotic susceptibility tests were applied to evaluate the effect of tcaA on the minimum inhibitory concentrations (MICs) of glycopeptides and ß-lactams. Scanning electron microscopy, RNA sequencing, and quantitative reverse transcription-polymerase chain reaction were performed to explore the mechanism of tcaA in MRSA resistance to ß-lactams. RESULTS: The MIC of penicillin plus clavulanate decreased from 3 mg/L to 0.064 mg/L and that of oxacillin decreased from 16 to 0.5 mg/L when tcaA was knocked out in the LAC strain. Compared with wild-type MRSA isolates, when tcaA was deleted, all selected strains were more susceptible to ß-lactams. Susceptibility to ceftobiprole was restored in the ceftobiprole-resistant strain when tcaA was deleted. tcaA knockout caused "log-like" abnormal division of MRSA, and tcaA deficiency mediated low expression of mecA, ponA, and murA2. CONCLUSIONS: Machine learning is a reliable tool for identifying drug resistance-related genes. tcaA may be involved in S. aureus cell division and may affect mecA, ponA, and murA2 expression. Furthermore, tcaA is a potential resistance breaker target for ß-lactams, including ceftobiprole, in MRSA.

Partial root-zone drying irrigation improves intrinsic water-use efficiency and maintains high photosynthesis by uncoupling stomatal and mesophyll conductance in cotton leaves.

Partial root-zone drying irrigation (PRD) can improve water-use efficiency (WUE) without reductions in photosynthesis; however, the mechanism by which this is attained is unclear. To amend that, PRD conditions were simulated by polyethylene glycol 6000 in a root-splitting system and the effects of PRD on cotton growth were studied. Results showed that PRD decreased stomatal conductance (gs) but increased mesophyll conductance (gm). Due to the contrasting effects on gs and gm, net photosynthetic rate (AN) remained unaffected, while the enhanced gm/gs ratio facilitated a larger intrinsic WUE. Further analyses indicated that PRD-induced reduction of gs was related to decreased stomatal size and stomatal pore area in adaxial and abaxial surface which was ascribed to lower pore length and width. PRD-induced variation of gm was ascribed to the reduced liquid-phase resistance, due to increases in chloroplast area facing to intercellular airspaces and the ratio of chloroplast surface area to total mesophyll cell area exposed to intercellular airspaces, as well as to decreases in the distance between cell wall and chloroplast, and between adjacent chloroplasts. The above results demonstrate that PRD, through alterations to stomatal and mesophyll structures, decoupled gs and gm responses, which ultimately increased intrinsic WUE and maintained AN.

Stepwise structural evolution toward robust carboranealkynyl-protected copper nanocluster catalysts for nitrate electroreduction.

Atomically precise metal nanoclusters (NCs) are emerging as idealized model catalysts for imprecise metal nanoparticles to unveil their structure-activity relationship. However, the directional synthesis of robust metal NCs with accessible catalytic active sites remains a great challenge. In this work, we achieved bulky carboranealkynyl-protected copper NCs, the monomer Cu13·3PF6 and nido-carboranealkynyl bridged dimer Cu26·4PF6, with fair stability as well as accessible open metal sites step by step through external ligand shell modification and metal-core evolution. Both Cu13·3PF6 and Cu26·4PF6 demonstrate remarkable catalytic activity and selectivity in electrocatalytic nitrate (NO3-) reduction to NH3 reaction, with the dimer Cu26·4PF6 displaying superior performance. The mechanism of this catalytic reaction was elucidated through theoretical computations in conjunction with in situ FTIR spectra. This study not only provides strategies for accessing desired copper NC catalysts but also establishes a platform to uncover the structure-activity relationship of copper NCs.

Single-cell 3D genome structure reveals distinct human pluripotent states.

BACKGROUND: Pluripotent states of embryonic stem cells (ESCs) with distinct transcriptional profiles affect ESC differentiative capacity and therapeutic potential. Although single-cell RNA sequencing has revealed additional subpopulations and specific features of naive and primed human pluripotent stem cells (hPSCs), the underlying mechanisms that regulate their specific transcription and that control their pluripotent states remain elusive. RESULTS: By single-cell analysis of high-resolution, three-dimensional (3D) genomic structure, we herein demonstrate that remodeling of genomic structure is highly associated with the pluripotent states of human ESCs (hESCs). The naive pluripotent state is featured with specialized 3D genomic structures and clear chromatin compartmentalization that is distinct from the primed state. The naive pluripotent state is achieved by remodeling the active euchromatin compartment and reducing chromatin interactions at the nuclear center. This unique genomic organization is linked to enhanced chromatin accessibility on enhancers and elevated expression levels of naive pluripotent genes localized to this region. In contradistinction, the primed state exhibits intermingled genomic organization. Moreover, active euchromatin and primed pluripotent genes are distributed at the nuclear periphery, while repressive heterochromatin is densely concentrated at the nuclear center, reducing chromatin accessibility and the transcription of naive genes. CONCLUSIONS: Our data provide insights into the chromatin structure of ESCs in their naive and primed states, and we identify specific patterns of modifications in transcription and chromatin structure that might explain the genes that are differentially expressed between naive and primed hESCs. Thus, the inversion or relocation of heterochromatin to euchromatin via compartmentalization is related to the regulation of chromatin accessibility, thereby defining pluripotent states and cellular identity.

Co-occurrence of elevated arsenic and fluoride concentrations in Wuliangsu Lake: Implications for the genesis of poor-quality groundwater in the (paleo-)Huanghe (Yellow River) catchment, China.

The co-occurrence of high As and F concentrations in saline groundwater in arid and semi-arid regions has attracted considerable attention. However, the factors determining the elevated concentrations of the two elements in surface water in these regions have not been sufficiently studied, and their implications for the poor-quality of local groundwater (high levels of As, F, and salinity) are unknown. A total of 18 water samples were collected from Wuliangsu Lake, irrigation/drainage channels, and the Huanghe (i.e., Yellow River) in the Hetao Basin, China. The pH, concentrations of As and F as well as those of other major elements, and stable isotope (H and O) compositions were analyzed. The water samples had a high pH (7.85-9.01, mean 8.25) and high TDS (402-9778 mg/L, mean 1920 mg/L) values. In six of the 10 lake samples, As concentration was above 10 µg/L (maximum 69.1 µg/L) and, in one of them, F concentration was above 1.5 mg/L. Interestingly, the high As, F, and TDS values simultaneously detected in the lake water were similar to those previously reported in local groundwater, and all water samples showed a significant positive correlation between As and F concentrations (R2 = 0.96, p < 0.01), except for two samples with abnormally high Ca2+ levels. The results of stable isotope analysis and Cl/Br ratios suggested that the lake experienced strong evaporation, which is consistent with the high TDS values. Evaporative concentration is suggested as the main factor contributing to the elevated As and F concentrations in the lake water. In addition, the major ions (e.g., Na+, Cl-, HCO3-, and OH-) and pH in the lake water increased during evaporation, leading to desorption of As and F. Thus, the evaporation process, including evaporative concentration and desorption, was considered primarily responsible for the elevated As and F in the lake water. Based on the results of this study, we presume that the paleolakes in the study area have experienced intense evaporation process. As a result, As, F, and major elements accumulated in sediments (or residual lake water) and were buried in the fluvial basins; then, they were released into the groundwater through multiple (bio)hydrogeochemical processes. By combining the results of this study with those obtained from previous groundwater analyses, we propose a new hypothesis explaining the origin of elevated As and F concentrations in saline groundwater in arid and semi-arid regions.