ObjectiveTo verify the association between the Ddit3-Trib3-Akt signaling pathway and rat spermatogenesis by constructing an in vitro co-culture system of testis. MethodsTesticular tissue blocks from 20-25-day-old male rats were placed in an in vitro culture system， and the culture medium was replaced every 2 to 3 days. PCR was used to verify the expression of marker genes of various spermatogenic cells. RNA interference technology was employed to verify the correlation between the Ddit3-Trib3-Akt signaling pathway and rat spermatogenesis. ResultsThe co-culture system could be continuously cultured for more than 2.5 months in vitro. RT-PCR showed that specific marker genes of spermatogonia， spermatocyte and spermoblast were expressed. The RNA and protein expression of Trib3 and Akt changed after the knocking down of Ddit3 and Trib3， respectively. It demonstrated the existence of Ddit3-Trib3-Akt signaling pathway in rat spermatogenesis. ConclusionThe culture time of more than 2.5 months indicates that the culture system can temporarily maintain the proliferation and differentiation of stem cells， and simultaneously maintain and stabilize spermatogenesis in a simple system. The successful validation of the Ddit3-Trib3-Akt signaling pathway also confirms that this culture system can be used to study possible molecular mechanisms of spermatogenesis in vitro.

Objective To explore the causal relationship between immune cells and heart failure (HF), and the mediating role of serum metabolites, in order to identify potential biomarkers and therapeutic targets. Methods We employed a two-sample Mendelian randomization (MR) analysis method based on genome-wide association study (GWAS) data, analyzing the direct and indirect effects of 731 types of immune cells and 1 400 metabolites on HF. We selected valid instrumental variables and conducted statistical analyses using R software. The primary analysis was performed using the inverse variance weighted method, supplemented by MR-Egger analysis and weighted median method. The stability of the results was assessed through tests such as Cochran’s Q test. Results Our research found a negative causal relationship between PD-L1 on CD14−CD16+ and HF. Sensitivity analysis supported this result. The reverse MR analysis did not find an effect of HF on PD-L1 on CD14−CD16+, indicating that PD-L1 on CD14−CD16+ might play a unidirectional role in reducing the risk of HF. Further mediation MR analysis showed that PD-L1 on CD14−CD16+ might influence the risk of HF onset by regulating the levels of sphingomyelin (d17:1/14:0, d16:1/15:0), with a mediation effect ratio of 6.7%. Conclusion PD-L1 on CD14−CD16+ may reduce the risk of HF by elevating the levels of sphingomyelin (d17:1/14:0, d16:1/15:0), which provides a new perspective for understanding the pathogenesis of HF.

To conduct a bibliometric and keyword analysis on the domestic and international literature of medical artificial intelligence （AI） ethics， explore the research frontiers， hotspots， and development trends in this field， and provide references for promoting the construction of China’s ethical governance system on medical AI. Utilizing CiteSpace software， a comparative analysis was conducted between the reviewed domestic and international literature regarding their publication volume， author and institutional collaboration networks， as well as keyword co-occurrence， clustering， timeline graph， and burst， to explore the research hotspots and development trends in the field. A total of 2 393 Chinese and English publications were included. In recent years， research topics in medical AI ethics both domestically and internationally focused on three aspects， encompassing their theoretical research， emerging domains and their ethical risks， as well as the ethical governance and regulation of medical AI. International research hotspots included federated learning， computer-aided detection， informed consent， and other aspects， whereas domestic research hotspots were smart healthcare， responsibility ethics， ethical values， and other aspects. Internationally， greater attention was placed on ethical issues concerning population health and healthcare in the public health domain， whereas domestic research topics tended to focus more on theoretical discussions and the establishment of ethical principles. The ethical governance of medical AI represents a shared global challenge， necessitating enhanced research into both the variances and commonalities in this field.

Iodine speciations in aquatic environments are affected by dissolved oxygen,redox potential,microbial activity,organic matter decomposition,light reaction,etc.Accurate quantification of iodine speciation can not only help to understand the geochemical cycle of iodine,but also help to trace and study environmental processes.Based on the combination of ion chromatography(IC)and inductively coupled plasma mass spectrometry(ICP-MS),a rapid and sensitive method was established for determining the speciations of iodine in environmental water samples including seawater,river water,lake water,rainwater,groundwater,etc.The results presented here showed that IO3?and I?in seawater were quickly separated and measured within 120 s when using guard column AG22 and 8 mmol/L(NH4)2CO3 as the mobile phase.While for lake water,river water and precipitation samples with high soluble organically bond iodine(SOI),an AS22 separation column(250 mm×4 mm)connected with a guard column and using 50 mmol/L(NH4)2CO3 as mobile phase could effectively separate unknown SOI from IO3? to achieve accurate quantification of IO3?.For accurate correction of iodine measurement signal fluctuations,133Cs was directly added to the(NH4)2CO3 mobile phase as an internal standard.The SOI content was calculated by the total iodine concentrations minus the sum of IO3?and I?.The precision of the established iodine speciation analytical method was better than 3.5%,and the standard addition experiment showed that the analytical method was accurate.When the injection volume was 25 μL,the detection limits were 0.011?0.025 μg/L for IO3? and 0.023?0.031 μg/L for I?,respectively.The method was successfully used to analyze IO3?,SOI and I? in environmental water samples,such as seawater,river water,rainwater and groundwater.

Chrysophanol(Chr)and physcion(Phy)are primary active ingredients of a well-known traditional Chinese medicine namely rhubarb(Chinese name:Dahuang),and their glucuronides have been revealed as the dominant forms presenting in rats after oral administration.Either Chr or Phy has two glycosylation sites,resulting in a pair of positional isomers for glucuronides of either compound(CG1&CG2 and PG1&PG2).To confirmatively identify these glucuronides,energy-resolved mass spectrometry(ER-MS)was used to pursue the fragmentation trajectories of the targeted fragment ions,and the resultant breakdown graphs that were described by the optimal collision energy(OCE)were expected to exhibit the differences of glycosidic bond cleavage between the isomers.Quantum chemical calculation was thereafter conducted to produce the bond dissociation energy(BDE)of the glycosidic bonds.The isomers were unambiguously identified through applying the positive correlation rule between OCE and BDE.Fortunately,the glucuronides of Chr and Phy in vivo were observed through liver microsomes incubationin vitro.ER-MS was utilized to collect the Gaussian-shaped breakdown graphs in response to the neutral loss of 176 Da,and the absolute values of OCE were compared between positional isomers.The results revealed that CG1(-32.31 eV)>CG2(-31.61 eV),and nonetheless,PG1(-30.00 eV)Chr-8-GluA(-48.787 kJ/mol),and nonetheless,Phy-1-GluA(-48.672 kJ/mol)

The telomere structure in the cell nucleus is crucial for maintaining the stability and functions of chromosomes.Telomerase is a ribonucleoprotein reverse transcriptase,which catalyzes the elongation of telomeres using its own RNA as a template,thereby counteracting the shortening of telomeres caused by chromosome replication and cell division.Due to its overexpression in over 85％of malignant tumor cells,telomerase has emerged as a highly promising biomarker and a novel target for cancer therapy.In recent years,given the importance of precise quantification of telomerase activity in guiding medical diagnosis and treatment strategies,researchers have developed various high-performance telomerase detection techniques.Among these,electrochemical biosensing technique has cause much attention due to its high sensitivity,operational convenience,rapid response,and ease of miniaturization.This paper focused on the latest advances in electrochemical sensing technique for detection of telomerase activity,aiming to provide inspiration for designing novel telomerase activity detection strategies by elucidating three unique properties of telomerase primer extension products.

Nitrofurantoin(NFT)is a nitrofuran antibiotic commonly used as a veterinary drug to treat bacterial infections in animals.However,due to the low solubility and bioaccumulation properties,NFT is prone to leave excessive residues in animal-derived foods and water systems,posing serious threats to human health and ecosystems.Therefore,there is an urgent need to develop an efficient and rapid detection method for NFT.In this work,nitrogen-doped carbon nanomaterials with unique bowl-like structures(N-CNBs)were synthesized via a hydrothermal-carbonization method.The morphology,surface structure,and specific surface area of N-CNBs were characterized using transmission electron microscopy(TEM),scanning electron microscopy(SEM),and X-ray photoelectron spectroscopy(XPS).The N-CNB modified glassy carbon electrode(N-CNB/GCE)was prepared,and the electrochemical test revealed that the N-CNB/GCE exhibited higher conductivity and larger electrochemical active surface area compared to bare GCE and nitrogen-doped hollow carbon nanosphere-modified electrode(N-HCNS/GCE).Additionally,the N-CNB/GCE demonstrated superior electrocatalytic activity toward NFT.An NFT electrochemical sensor was constructed based on N-CNB/GCE.The detection conditions of the sensor were optimized,and differential pulse voltammetry(DPV)was employed for NFT detection under optimal experimental conditions.The established NFT electrochemical sensor had a wide linear range of 0.4-500 μmol/L,a low detection limit(S/N=3)of 0.015 μmol/L and high selectivity,with excellent stability and reproducibility.The practical feasibility of this sensor was confirmed by analysis of NFT in milk and tap water samples,with spiked recoveries ranging from 94.2%to 108.9%.

The cycling of iodine in the atmosphere and ocean plays a critical role in climate and environmental change.Ice cores and tree rings,as ideal climate archives,can provide essential data for paleoclimate reconstruction through accurate iodine analysis.However,iodine concentrations in ice core samples are as low as 0.01 μg/L,and as low as 0.01 μg/g in tree rings.Most currently reported analytical methods face challenges in accurately quantifying such low levels.In this study,a highly sensitive analytical method for trace iodine in environmental samples was developed based on inductively coupled plasma mass spectrometry(ICP-MS),incorporating a collision/reaction cell under the optimized collision/reaction gas conditions.Collision/reaction cell mode was employed to evaluate potential interferences in determination of trace iodine by ICP-MS.The results indicated that peak tailing from adjacent mass-to-charge ratios and polyatomic ion interferences could be considered negligible.However,residual iodine in ultrapure water constituted the major source of background,highlighting the need for strict control of sample pretreatment and procedural blanks in trace-level iodine analysis.By utilizing collision focusing effect of helium,the measurement sensitivity of iodine was enhanced to 3.5×105 cps(counts per second)/(μg/L),and the detection limit was reduced to 0.002 μg/L.The developed method exhibited a deviation of less than 2.3%in measurement of low-concentration standard solutions,indicating good accuracy.For actual samples and blanks,the precision of repeated measurements within 2 h was better than 1.6%,demonstrating excellent repeatability.No significant memory effect was observed during the measurements.The established method was successfully applied to determination of trace iodine in ice cores,tree rings,and other environmental samples,providing a robust technical foundation for investigating the role of iodine in climate and environmental change.

Objective To investigate the carrying status and drug resistance analysis of pathogenic bacteria in the gut of healthy population in Huadu District,Guangzhou,and provide reference for epidemiological re-search.Methods A total of 337 459 anal swabs were directly isolated and cultured from healthy individuals who underwent physical examinations from 2018 to 2023.600 anal swabs from 2022 were randomly selected for multi pathogen nucleic acid testing,direct isolation and culture,and enrichment culture.Identification of bacteria was conducted by using VITEK 2 Compact and VITEK MS,serological testing was used for determi-nation of type,and drug susceptibility testing of pathogenic bacteria was conducted.Results A total of 128 pathogenic bacteria were isolated from rectal swabs,including 52 strains of Salmonella,71 strains of Aero-monas,3 strains of Vibrio parahaemolyticus,and 2 strains of Shigella flexneri,with a total detection rate of 3.79/10 000.The detection rate of Salmonella in direct isolation and culture of 600 rectal swabs was 0.50％,the detection rate of enrichment culture was 1.00％,and the detection rate of multi-pathogen nucleic acid de-tection was 1.17％.52 strains of Salmonella were divided into 27 serotypes,and Salmonella Ⅰ 4,5,12:i:—was the dominant serotype.Aeromonas sobria was the dominant serotype in Aeromonas.The sensitivity of Salmonella to piperacillin/tazobactam,imipenem,cefepime,levofloxacin,and aztreonam was up to 92.00％or more,however,the phenomenon of multidrug resistance was severe,with a multidrug resistance rate as high as 40.38％.The resistance rate of Aeromonas to ampicillin and ampicillin/sulbactam was up to 85.00％or more,while Aeromonas was relatively sensitive to other antibiotics.Conclusion There are many species and types of intestinal pathogenic bacteria carried by healthy individuals in Huadu District,Guangzhou,with Aero-monas and Salmonella ranking first and second,and levofloxacin treatment could be preferred.The use of bac-terial culture and multi pathogen nucleic acid testing methods could improve the detection rate of intestinal pathogenic bacteria,and attention should be paid to the monitoring of intestinal pathogenic bacteria among rel-evant practitioners.

Objective To explore the effects of different methods on the culture results of Mycobacterium marinum,including direct inoculation,grinding followed by digestion,and digestion followed by grinding.Methods From June 2022 to March 2024,122 patients with suspected Mycobacterium marinum infection were collected from the Department of Dermatology in this hospital,including 44 cases with superficial skin type and 78 cases with subcutaneous tissue type.Direct inoculation,grinding followed by and digestion followed by grinding were used respectively to analyze the effects of these three methods on the positive detection rate and contamination rate of Mycobacterium marinum culture.Results The culture positive detection rate of Myco-bacterium marinum in superficial skin type and in subcutaneous tissue type were 47.7％(21/44)and 67.9％(53/78),respectively.The use of grinding combined with digestion method for processing skin or subcutane-ous tissue specimens results in a higher positive detection rate and a lower contamination rate compared with the direct inoculation method,with statistically significant differences(P＜0.05).For superficial skin type specimens,the grinding followed by digestion method had a higher positive detection and a lower contamina-tion rate than the digestion followed by grinding method,with statistically significant differences(P＜0.05).For subcutaneous tissue samples,the grinding followed by digestion method had a higher positive detection rate compared to the digestion followed by grinding method,but the difference was not statistically significant(P＞0.05).There were no significant differences in the primary culture time of Mycobacterium marinum a-mong the three pretreatment methods(P＞0.05).Conclusion The pretreatment of skin tissue samples with grinding followed by digestion,and the pretreatment of subcutaneous tissue samples with grinding followed by digestion or digestion followed by grinding can significantly improve the positive rate of Mycobacterium mari-num culture and reduce the contamination rate of miscellaneous bacteria.