Low barriers to internal rotation in the microwave spectrum of 2,5-dimethylfluorobenzene.

We investigated the rotational spectrum of 2,5-dimethylfluorobenzene containing coupled large amplitude motions of two methyl groups in the frequency range from 2 to 26.5 GHz using a pulsed molecular jet Fourier transform microwave spectrometer. The internal rotation of two inequivalent methyl groups with low torsional barriers (around 16 and 226 cm-1) causes splittings of all rotational transitions into quintets with separations of up to hundreds of MHz between the torsional components. Spectral analysis and modeling of the observed splittings were performed using the programs XIAM and BELGI-Cs-2Tops, whereby the latter achieved measurement accuracy. The methyl internal rotation can be used to examine the electronic and steric environments around the methyl group because they affect the methyl torsional barrier. Electronic properties play a particularly important role in aromatic molecules in the presence of a π-conjugated double bond system. The experimental results were compared with those of quantum chemistry. Benchmark calculations resulted in the conclusion that the B3LYP-D3BJ/6-311++G(d,p) level of theory can be recommended for predicting rotational constants to guide the microwave spectral assignment of dimethylfluorobenzenes in particular and toluene derivatives in general.

Quantifying soft degrees of freedom in volatile organic compounds: insight from quantum chemistry and focused single molecule experiments.

Sampling of the vast conformational landscape of organic compounds remains a challenging task in computational chemistry, especially when it comes to the characterization of soft-degrees of freedom and relatively small energy barriers between different local minima. Therefore, studying the intrinsic properties of isolated molecules using focused experiments such as high-resolution molecular spectroscopy provides a powerful approach to validate and improve available quantum chemical methods. Here, we report on the most abundant gas-phase structure of ethyl 2-methyl pentanoate under molecular jet conditions, which we used to benchmark several exchange-correlation functionals and ab initio methods at the quantum chemical level. The observed conformer of ethyl 2-methyl pentanoate in the gas-phase is of C1 symmetry and exhibits a large amplitude motion around the C-C bond in proximity to the carbonyl moiety, which, unlike in the case of its structural isomer ethyl 2-ethyl butyrate, is very sensitive to the applied quantum chemical method and basis set. Depending on the applied quantum chemical method, the dihedral angle of the lowest energy conformer is optimized to absolute values of ±20°. This is far above the usual convergence error of the theoretical methods and has a tremendous impact on the rotational constants of this conformer, which complicates the prediction of rotational spectra and the assignment of experimental data. We show that the loss of symmetry in the aliphatic chain bound to the carboxylic moiety of ethyl esters results in a shift of the dihedral angle value due to a flat potential well around the corresponding C-C bond. Our benchmark calculations further indicate the potential relevance of the wB97X-D functional for this ethyl pentanoate and other related ethyl esters.

Development and validation of a prediction model for suboptimal ovarian response in polycystic ovary syndrome (PCOS) patients undergoing GnRH-antagonist protocol in IVF/ICSI cycles.

BACKGROUND: PCOS patients with unexpectedly low oocyte yield following conventional ovarian stimulation are referred to as suboptimal responders. However, identifying suboptimal responders presents a significant challenge within reproductive medicine and limited research exists on the occurrence of suboptimal response. This analysis aimed to develop a predictive model of suboptimal response during in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatments in PCOS patients. METHODS: This retrospective study involved a cohort of 313 PCOS patients undergoing their first IVF/ICSI cycle from 2019 to 2022. Univariate logistic regression analyses, least absolute shrinkage, selection operator regression analysis, and recursive feature elimination were employed to identify relevant characteristics and construct predictive models. Moreover, a nomogram was constructed based on the best model. Receiver operating characteristic curves, decision curve analysis (DCA), and calibration curves were used to evaluate the model. RESULTS: The predictors included in the model were age, Anti-Mullerian hormone, antral follicle count, and basal follicle-stimulating hormone. The area under the receiver operating characteristic curve (AUC) was 0.7702 (95% confidence interval 0.7157-0.8191). The AUC, along with the DCA curve and calibration curve, demonstrated a satisfactory level of congruence and discrimination ability. CONCLUSION: The nomogram effectively predicted the probability of suboptimal response in PCOS patients undergoing gonadotropin-releasing hormone antagonist protocol during IVF/ICSI treatment.

Development and validation of a prediction model for unexpected poor ovarian response during IVF/ICSI.

Background: Identifying poor ovarian response (POR) among patients with good ovarian reserve poses a significant challenge within reproductive medicine. Currently, there is a lack of published data on the potential risk factors that could predict the occurrence of unexpected POR. The objective of this study was to develop a predictive model to assess the individual probability of unexpected POR during in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatments. Methods: The development of the nomogram involved a cohort of 10,404 patients with normal ovarian reserve [age, ≤40 years; antral follicle count (AFC), ≥5; and anti-Müllerian hormone (AMH), ≥1.2 ng/ml] from January 2019 to December 2022. Univariate regression analyses and least absolute shrinkage and selection operator regression analysis were employed to ascertain the characteristics associated with POR. Subsequently, the selected variables were utilized to construct the nomogram. Results: The predictors included in our model were body mass index, basal follicle-stimulating hormone, AMH, AFC, homeostasis model assessment of insulin resistance (HOMA-IR), protocol, and initial dose of gonadotropin. The area under the receiver operating characteristic curve (AUC) was 0.753 [95% confidence interval (CI) = 0.7257-0.7735]. The AUC, along with the Hosmer-Lemeshow test (p = 0.167), demonstrated a satisfactory level of congruence and discrimination ability of the developed model. Conclusion: The nomogram can anticipate the probability of unexpected POR in IVF/ICSI treatment, thereby assisting professionals in making appropriate clinical judgments and in helping patients to effectively manage expectations.

Genome-wide association studies reveal novel QTLs for agronomic traits in soybean.

Introduction: Soybean, as a globally significant crop, has garnered substantial attention due to its agricultural importance. The utilization of molecular approaches to enhance grain yield in soybean has gained popularity. Methods: In this study, we conducted a genome-wide association study (GWAS) using 156 Chinese soybean accessions over a two-year period. We employed the general linear model (GLM) and the mixed linear model (MLM) to analyze three agronomic traits: pod number, grain number, and grain weight. Results: Our findings revealed significant associations between qgPNpP-98, qgGNpP-89 and qgHGW-85 QTLs and pod number, grain number, and grain weight, respectively. These QTLs were identified on chromosome 16, a region spanning 413171bp exhibited associations with all three traits. Discussion: These QTL markers identified in this study hold potential for improving yield and agronomic traits through marker-assisted selection and genomic selection in breeding programs.

Application of topical pharyngeal anesthesia to reduce adverse reactions during painless gastroscopy: A prospective randomized study.

BACKGROUND: Studies have reported that certain adverse reactions can occur during painless gastroscopy examination. Knowing how to decrease the risks and incidence of adverse reactions is of great importance. OBJECTIVE: To investigate whether topical pharyngeal anesthesia combined with intravenous anesthesia is superior to intravenous anesthesia alone in patients undergoing painless gastroscopy and to determine whether this combined approach had any additional benefits. METHODS: Three hundred patients undergoing painless gastroscopy were randomly assigned to either the control group or the experimental group. In the control group, patients were anesthetized with propofol, while patients in the experimental group received propofol combined with 2% lidocaine spray for topical pharyngeal anesthesia. Hemodynamic parameters before and after the procedure, including the heart rate (HR), mean arterial pressure (MAP), and pulse oxygen saturation (SPO2) were recorded. Any adverse reactions experienced by the patient, including choking and respiratory depression, and the total dosage of propofol required during each procedure were also documented. RESULTS: Compared with pre-anesthetic data, the HR, MAP, and SPO2 were reduced after the completion of the painless gastroscopy procedure in both groups. However, the HR, MAP, and SPO2 measurements taken after the gastroscopy were significantly lower in the control group than those of the experimental group (P< 0.05); thus, the hemodynamic parameters of the experimental group were more stable. Compared with the control group, there was significant reduction in the total amount of propofol administered in the experimental group (P< 0.05). The incidence of adverse reactions, including choking and respiratory depression, was significantly lower in the experimental group (P< 0.05). CONCLUSION: The results demonstrated that the application of topical pharyngeal anesthesia in painless gastroscopy can significantly reduce the incidence of adverse reactions. Thus, the combination of topical pharyngeal and intravenous anesthesia is worthy of clinical application and promotion.

Observation of the application effect of low-volume polyethylene glycol electrolyte lavage solution (PEG-ELS) combined with ascorbic acid tablets in bowel preparation for colonoscopy in hospitalized patients.

Background: This study explored the effectiveness and safety of low-volume polyethylene glycol electrolyte lavage solution (PEG-ELS) combined with ascorbic acid tablets (PEG-ELS/Asc) in bowel preparation for a colonoscopy. Methods: A total of 240 hospitalized patients who underwent a colonoscopy in Wenzhou People's Hospital, Wenzhou Third Clinical College of Wenzhou Medical University from July 2020 to June 2022 were randomly divided into two groups, with 120 patients each. All of the participants were given a low-residue or residue-free diet one day before the examination and fasted after dinner (completed before 18:00) the day before the examination. The 2-L PEG-ELS/Asc group took 2-L PEG-ELS plus 10 g ascorbic acid tablets once orally, while the 3-L PEG-ELS group took 3-L PEG orally on several occasions. The primary endpoint was the achievement of preparation adequacy and an overall colon cleansing score of ≥6, both assessed by blinded investigators using the Boston Bowel Preparation Scale (BBPS). The bowel cleansing effect, polyp detection rate, adverse reaction rate, oral drug tolerance rate, renal function, and electrolyte level changes were also compared between the two patient groups. Results: There were no significant differences in the success rate of bowel preparation, the detection rate of polyps, or the adverse reaction rate between the two groups (P > 0.05). The tolerance rate of bowel preparation in the 2-L PEG-ELS/Asc group was significantly higher than that in the 3-L PEG-ELS group (93.3% vs. 80.23%) (P < 0.05). The levels of creatinine, serum potassium, serum sodium, and serum chlorine of the two groups before and after bowel preparation were within the normal range. In addition, the intestinal cleaning effect of the two preparation schemes for the hospitalized patients with diabetes and constipation is worse than that of those without these conditions (P < 0.05). Conclusion: The effectiveness and safety of using 2-L PEG-ELS/Asc in bowel preparation for a colonoscopy in hospitalized patients were not inferior to using 3-L PEG-ELS. For patients with diabetes and constipation, the cleansing effect of the two bowel preparation options was not very satisfactory, and further clinical research is needed in this regard.

Salt altered rhizosphere fungal community and induced soybean recruit specific species to ameliorate salt stress.

Different crop genotypes showed different adaptability to salt stress, which is partly attributable to the microorganisms in the rhizosphere. Yet, knowledge about how fungal communities of different genotypes in soybean respond to salt stress is limited. Here, qPCR and ITS sequencing were used to assess the response of rhizobial fungal communities of resistant and susceptible soybean to salt stress. Moreover, we isolated two fungal species recruited by resistant soybeans for validation. The assembly of fungal community structure might be strongly linked to alterations in fungal abundance and soil physicochemical properties. Salt stress derived structural differences in fungal communities of resistant and susceptible genotypes. The salt-resistant genotype appeared to recruit some fungal taxa to the rhizosphere to help mitigating salt stress. An increase of fungal taxa with predicted saprotrophic lifestyles might help promoting plant growth by increasing nutrient availability to the plants. Compared with the susceptible genotypes, the resistant genotypes had more stronger network structure of fungi. Lastly, we verified that recruited fungi, such as Penicillium and Aspergillus, can soybean adapt to salt stress. This study provided a promising approach for rhizospheric fungal community to enhance salt tolerance of soybean from the perspective of microbiology and ecology.

Effects of salt stress on soil enzyme activities and rhizosphere microbial structure in salt-tolerant and -sensitive soybean.

Salt is recognized as one of the most major factors that limits soybean yield in acidic soils. Soil enzyme activity and bacterial community have a critical function in improving the tolerance to soybean. Our aim was to assess the activities of soil enzyme, the structure of bacteria and their potential functions for salt resistance between Salt-tolerant (Salt-T) and -sensitive (Salt-S) soybean genotypes when subject to salt stress. Plant biomass, soil physicochemical properties, soil catalase, urease, sucrase, amylase, and acid phosphatase activities, and rhizosphere microbial characteristics were investigated in Salt-T and Salt-S soybean genotypes under salt stress with a pot experiment. Salt stress significantly decreased the soil enzyme activities and changed the rhizosphere microbial structure in a genotype-dependent manner. In addition, 46 ASVs which were enriched in the Salt-T geotype under the salt stress, such as ASV19 (Alicyclobacillus), ASV132 (Tumebacillus), ASV1760 (Mycobacterium) and ASV1357 (Bacillus), which may enhance the tolerance to soybean under salt stress. Moreover, the network structure of Salt-T soybean was simplified by salt stress, which may result in soil bacterial communities being susceptible to external factors. Salt stress altered the strength of soil enzyme activities and the assembly of microbial structure in Salt-T and Salt-S soybean genotypes. Na+, NO3--N, NH4+-N and Olsen-P were the most important driving factors in the structure of bacterial community in both genotypes. Salt-T genotypes enriched several microorganisms that contributed to enhance salt tolerance in soybeans, such as Alicyclobacillus, Tumebacillus, and Bacillus. Nevertheless, the simplified network structure of salt-T genotype due to salt stress may render its bacterial community structure unstable and susceptible.

Comprehensive analysis of circular RNA-associated competing endogenous RNA networks and immune infiltration in gastric cancer.

BACKGROUND: Circular RNA (circRNA) has been proved to be an important regulator of gastric cancer (GC). However, the role and regulatory mechanism of circrna related competitive endogenous RNA (ceRNA) in GC have not been established. METHODS: CircRNA data and clinical data were obtained from the GEO and TCGA databases. The ceRNA networks were constructed and a function enrichment analysis was completed. Additionally, correlations between hub genes expression, immune cell infiltration, and clinical phenotypes were determined. The differentially expressed circRNAs and their downstream microRNAs (miRNAs) were validated by quantitative real-time polymerase chain reaction, and the hub genes were validated by western blot analysis. The migration and invasion ability of overexpressed hsa_circ_0002504 was determined by a transwell assay. RESULTS: The ceRNA network contained 2 circRNAs, 3 miRNAs, and 55 messenger RNAs (mRNAs). 323 biological processes terms, 53 cellular components terms, 51 molecular functions terms, and 4 signaling pathways were revealed by the function enrichment analysis. The GSEA analysis revealed that the hub genes were positively correlated with the axon guidance and adhesion molecules pathways. The correlation analysis revealed that overexpressed EPHA4 and KCNA1 indicated poor tissue differentiation and were associated with clinically advanced stages of GC. The in vitro experiments showed that hsa_circ_0002504 was significantly down-regulated in GC cell lines. In addition, the overexpression of hsa_circ_0002504 led to a significant downregulation of hsa-miR-615-5p and hsa-miR-767-5p, as well as an upregulation of EPHA4, KCNA1, and NCAM1. Furthermore, it suppressed the migration and invasion ability of GC cells. CONCLUSIONS: Hsa_circ_0002504 is a potential diagnostic biomarker for GC. High expression of EPHA4 and KCNA1 may indicate poor prognosis.

Considering single-atom catalysts as photocatalysts from synthesis to application.

With the ever-increased greenhouse effect and energy crisis, developing novel photocatalysts to realize high-efficient solar-driven chemicals/fuel production is of great scientific and practical significance. Recently, single-atom photocatalysts (SAPs) are promising catalysts with maximized metal dispersion and tuneable coordination environments. SAPs exhibit boosted photocatalytic performance by enhancing optical response, facilitating charge carrier transfer behaviors or directly manipulating surface reaction processes. In this regard, this article systematically reviews the state-of-the-art progress in the development and application of SAPs, especially the mechanism and performance of SAPs on various reaction processes. Some future challenges and potential research directions over SAPs are outlined at the final stage.

Factors Affect the Eradication Rate of Helicobacter pylori by Modified Quadruple Therapy: A Prospective Cohort Study.

Objective: This study aimed to investigate related factors affecting the eradication rate of Helicobacter pylori (Hp) by modified quadruple therapy. Methods: Between September 2020 and March 2021, 341 patients who were diagnosed with Hp infection and whose infections were confirmed by gastroscopy, a histological examination, and a C13-UBT without culturing and antimicrobial susceptibility studies received a two-week anti-Hp treatment, a modified quadruple therapy, in our department. The result of C13-UBT was rechecked 4 weeks after the drug withdrawal, and the patients were divided into two groups-a success group and a failure group-according to the final breath result. The general clinical information and related laboratory indexes of each patient were collected, and the factors affecting the eradication rate were analyzed. Results: The total clinical eradication rate was 80.06% (273/341), and the failure rate was 19.94% (68/341), correspondingly. Univariate analysis identified statistically significant differences between the two groups in serum 25-hydroxyvitamin D levels, presence of oral diseases, positive cytotoxin-associated gene A (CagA), and medical compliance (P < 0.05). Meanwhile, the use of a proton pump inhibitor (PPIs) and antibiotics was statistically different (P < 0.05). Logistic regression analysis revealed that vitamin D level (<20 ng/mL) [OR = 98.56, 95% CI (29.01-334.83), P < 0.001] and medical compliance [OR = 148.18, 95% CI (37.64-583.33), P < 0.001] were independent effecting factors for eradication rate. Conclusion: Serum 25-hydroxyvitamin D level lower than 20 ng/mL may affect the success of eradication of Hp and is an independent risk factor for eradication failure.

In vivo detection of plaque erosion by intravascular optical coherence tomography using artificial intelligence.

Plaque erosion is one of the most common underlying mechanisms for acute coronary syndrome (ACS). Optical coherence tomography (OCT) allows in vivo diagnosis of plaque erosion. However, challenge remains due to high inter- and intra-observer variability. We developed an artificial intelligence method based on deep learning for fully automated detection of plaque erosion in vivo, which achieved a recall of 0.800 ± 0.175, a precision of 0.734 ± 0.254, and an area under the precision-recall curve (AUC) of 0.707. Our proposed method is in good agreement with physicians, and can help improve the clinical diagnosis of plaque erosion and develop individualized treatment strategies for optimal management of ACS patients.

Exogenous melatonin enhances cell wall response to salt stress in common bean (Phaseolus vulgaris) and the development of the associated predictive molecular markers.

Common bean (Phaseolus vulgaris) is an important food crop; however, its production is affected by salt stress. Salt stress can inhibit seed germination, promote senescence, and modify cell wall biosynthesis, assembly, and architecture. Melatonin, an indole heterocycle, has been demonstrated to greatly impact cell wall structure, composition, and regulation in plants under stress. However, the molecular basis for such assumptions is still unclear. In this study, a common bean variety, "Naihua" was treated with water (W), 70 mmol/L NaCl solution (S), and 100 µmol/L melatonin supplemented with salt solution (M+S) to determine the response of common bean to exogenous melatonin and explore regulatory mechanism of melatonin against salt stress. The results showed that exogenous melatonin treatment alleviated salt stress-induced growth inhibition of the common bean by increasing the length, surface area, volume, and diameter of common bean sprouts. Moreover, RNA sequencing (RNA-seq) and real-time quantitative PCR (qRT-PCR) indicated that the cell wall regulation pathway was involved in the salt stress tolerance of the common bean enhanced by melatonin. Screening of 120 germplasm resources revealed that melatonin treatment improved the salt tolerance of more than 65% of the common bean germplasm materials. Melatonin also up-regulated cell wall pathway genes by at least 46%. Furthermore, we analyzed the response of the common bean germplasm materials to melatonin treatment under salt stress using the key genes associated with the synthesis of the common bean cell wall as the molecular markers. The results showed that two pairs of markers were significantly associated with melatonin, and these could be used as candidate markers to predict whether common bean respond to exogenous melatonin and then enhance salt tolerance at the sprouting stage. This study shows that cell wall can respond to exogenous melatonin and enhance the salt tolerance of common bean. The makers identified in this study can be used to select common bean varieties that can respond to melatonin under stress. Overall, the study found that cell wall could response melatonin and enhance the salt tolerance and developed the makers for predicting varieties fit for melatonin under stress in common bean, which may be applied in the selection or development of common bean varieties with abiotic stress tolerance.

Molecular mechanisms of flavonoid accumulation in germinating common bean (Phaseolus vulgaris) under salt stress.

Flavonoids are important secondary metabolites, active biomolecules in germinating beans, and have prominent applications in food and medicine due to their antioxidant effects. Rutin is a plant flavonoid with a wide biological activity range. In this study, flavonoid (rutin) accumulation and its related molecular mechanisms in germinating common bean (Phaseolus vulgaris) were observed at different time points (0-120 h) under salt stress (NaCl). The rutin content increased from germination onset until 96 h, after which a reducing trend was observed. Metabolome analysis showed that salt stress alters flavonoid content by regulating phenylpropanoid (ko00940) and flavonoid (ko00941) biosynthesis pathways, as well as their enzyme activities, including cinnamyl-alcohol dehydrogenase (CAD), peroxidase (POD), chalcone isomerase (CHI), and flavonol synthase (FLS). The RNA-seq and quantitative real-time PCR (qRT-PCR) analyses also showed that these two pathways were linked to changes in flavonoid content following salt treatment. These results reveal that salt stress effectively enhanced rutin content accumulation in germinating beans, hence it could be employed to enhance the functional quality of germinating common beans.