Objective To evaluate the predictive value of different machine learning models constructed in a multicenter environment for potential organ donors and verify their clinical application feasibility. Methods The study included 2 000 inpatients admitted to five domestic tertiary hospitals from January 2020 to December 2023, who met the criteria for potential organ donation assessment. They were randomly divided into a training set and an internal validation set (7∶3). Another 300 similar patients admitted to the First Affiliated Hospital of Harbin Medical University from January 2024 to April 2025 were included as an external validation set. The area under the curve (AUC), sensitivity, specificity, accuracy and F1-score of three models were compared, and the consistency of the potential organ donor determination process was tested. Multivariate logistic regression analysis was used to identify predictive factors of potential organ donors. Decision curve analysis (DCA) was employed to verify the resource efficiency of each model, and the threshold interval and intervention balance point were assessed. Results Apart from age, there were no significant differences in other basic characteristics among the centers (all P>0.05). The consistency of the potential organ donor determination process among researchers in each center was good [all 95% confidence interval (CI) lower limits >0]. In the internal validation set, the XGBoost model had the best predictive performance (AUC=0.92, 95% CI 0.89-0.94) and the best calibration (P=0.441, Brier score 0.099). In the external validation set, the XGBoost model also had the best predictive performance (AUC=0.91, 95% CI 0.88-0.94), outperforming logistic regression and random forest models. Multivariate logistic regression showed that mechanical ventilation had the greatest impact (odds ratio=2.06, 95% CI 1.54-2.76, P<0.001). DCA indicated that the XGBoost model had the highest net benefit in the threshold interval of 0.2-0.6. The “treat all” strategy only had a slight advantage at extremely low thresholds. The recommended threshold interval, which balances intervention costs and clinical benefits, considers ≥50% positive predictive value (PPV) and ≤50 referrals per 100 high-risk patients. Conclusions The XGBoost model established in a multicenter environment is accurate and well-calibrated in predicting potential organ donors. Combined with DCA, it may effectively guide the timing of clinical interventions and resource allocation, providing new ideas for the assessment and management of organ donation after brain death.

Objective:To investigate the correlation between transabdominal bowel ultrasongraphy (TBUS) parameters and disease activity of ulcerative colitis (UC).Methods:The results of TBUS, endoscopy and laboratory tests of 68 UC patients (108 examinations) who visited the Department of Gastroenterology of the Second Hospital (Eastern Campus) of Hebei Medical University From January 2022 to February 2024 were retrospectively analyzed. According to Mayo endoscopic score (MES), there were 10 cases of remission (MES=0) and 98 cases of active phase (MES>0); patients in active phase further classified into 16 cases of mild (MES=1), 19 cases of moderate (MES=2), and 63 cases of severe (MES=3). The TAUS parameters were compared between patients in remission and active phases. Spearman rank correlation analysis was used to analyze the correlation between the TBUS parameters including bowel wall thickness (BWT), Limberg score, wall layer stratification, fat wrapping and endoscopic activity score, laboratory inflammatory indicators. Receiver operating characteristic curve (ROC) analysis was applied to evaluate the predictive efficacy of the TBUS parameters and laboratory inflammatory indicators in identifying remission under endoscopy. Independent sample t-test and Fisher′s exact probability method were used to compare the two groups. Results:The BWT of patients in remission was significantly thinner than that of patients in active phase ((2.99±0.41) mm vs. (5.66±1.57) mm, t=-5.34, P<0.001). The proportions of patients in remisson with Limberg score ≤2, normal wall layer stratification, and absence of fat wrapping were significantly higher than those of patients in active phase (10/10 vs. 34/98, 10/10 vs. 48/98, 10/10 vs. 41/98, Fisher′s exact test, P<0.001, =0.002, =0.001). BWT, Limberg score, wall layer stratification, and fat wrapping were positively correlated with MES ( r=0.676, 0.677, 0.441, and 0.493, all P<0.001). BWT and Limberg score were moderate positively correlated with C-hypersensitive reactive protein, erythrocyte sedimentation rate and fecal calprotectin (BWT: r=0.561, 0.420 and 0.458, all P<0.001; Limberg score: r=0.576, 0.469 and 0.403, all P<0.001), and were negatively correlated with serum albumin and hemoglobin (BWT: r=-0.604 and -0.453, both P<0.001; Limberg score: r=-0.573 and -0.532, both P<0.001). The results of ROC analysis showed that BWT achieved the best predictive efficacy in identifying endoscopic remission, and the best cut-off value was 3.45 mm (area under the curve was 0.972, 95% confidence interval: 0.944 to 1.000, P<0.001), with a sensitivity of 93.9% and specificity of 100.0%. Conclusions:TBUS parameters can accurately reflect disease activity in UC. It is a powerful tool for UC monitoring. The BWT<3.45 mm is the best cut-off value in prediction of endoscopic remission.

OBJECTIVE To provide scientific and reasonable recommendations for the identification of Anaerobio-spirillum succiniciproducens in clinical microbiology laboratories by comparing the effectiveness of biochemical methods,matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS),and 16S rRNA gene sequencing.METHODS Methodological evaluation was conducted.A strain of A.succiniciprodu-cens was isolated on Mar.27,2023 from a patient with sepsis caused by a dog bite,who was admitted to Guang-dong Nongken Central Hospital,and analyzed for the morphological characteristics,culture methods,and colony features.The identification of the isolated strain was conducted by the automated microbial identification and anal-ysis system(VITEK 2 Compact 2,bioMerieux),MALDI-TOF MS including VITEK MS,MALDI Biotyper,Au-tof ms 1000,and EX-Accuspec,as well as 16S ribosomal RNA(rRNA)gene sequencing.The performance of each method was evaluated.RESULTSA.succiniciproducens was a strictly anaerobic gram-negative spiral bacteri-um,characterized by slow growth,flat and colorless transparent colonies,and negative oxidase and catalase activ-ity.When using VITEK 2 Compact ANC card,it was not successfully recognized;however,through the identifi-cation by VITEK MS,MALDI Biotyper,Autof ms 1000 and EX-Accuspec,it was all confirmed as A.succinicip-roducens.Additionally,16S rRNA gene sequencing technology also identified it as A.succiniciproducens.CONCLUSIONS Current automated biochemical identification systems are unable to accurately identify A.succi-niciproducens.MALDI-TOF MS and 16S rRNA gene sequencing techniques can reliably confirm A.succinicipro-ducens.Clinical microbiologists should select the appropriate identification method based on their available re-sources.

Objective:To find out about the sentiment about the current physical training among Air Force pilots (cadets), propose methods for optimizing their programs of physical training, and to enhance the effectiveness of training in order to improve flight adaptability.Methods:A total of 1 135 pilots (cadets) were randomly selected as the subjects and divided into 3 groups according to types of aircraft and types of personnel: group A (pilots of fighters, bombers and advanced trainers), group B (pilots of fighter bombers, transporters, helicopters, special aircraft and junior trainers), and group C (flying cadets). A questionnaire survey was conducted to collect data on current physical training among pilots and flying cadets.Results:A total of 1 135 questionnaires were distributed, with 1 086 valid responses collected, yielding an effective response rate of 95.68%. Of the 1 086 participating pilots (cadets), 209 were in Group A, 499 in Group B, and 378 in Group C.There was statistically significant difference in the frequency and duration of weekly physical training between the 3 groups ( χ2=82.23, 61.56, both P<0.001). The proportion of participants engaging in >3 h weekly physical training sessions was significantly higher in group C (71.7%) than in group A (38.8%) and group B (44.9%). Significant differences were observed in weekly training durations between group C and group A (all P<0.05), as well as between group C and group B in the training durations of <3 h and 5-7 h (all P<0.05). The percentage of subjects who trained for 5-7 h per week was the highest in group C (41.5%). In groups A and B, pilots mostly trained for 3-<5 h per week (51.7% and 39.9%, respectively). The survey on the willingness to adjust training programs revealed statistically significant differences between the 3 groups in their willingness to engage in muscle strength training, coordination training, specific ability training, and adjustment of intensities of core training ( H=46.23, 16.12, 22.03, 60.68, all P<0.001). No significant difference was observed in their willingness to have aerobic training programs adjusted ( P>0.05). Group C was significantly different from groups A and B in their preference for adjustment in training programs related to muscle strength, coordination, specific abilities, and in core training programs (all P<0.01). Group C was mostly in favor of "increasing" muscle strength, coordination, and core training while opting for "no change" in aerobic training and specific ability training. Groups A and B preferred "no change". Regarding their willingness to have training intensities revised, statistically significant differences were observed between the 3 groups ( H=15.58, 19.08, 8.17, 58.01, P<0.001, <0.001, =0.017, <0.001), but no significant difference was found in their preference for adjustment of aerobic training intensities ( P>0.05). Group C showed much more preference for intensity adjustment related to muscle strength, coordination, specific abilities, and core training programs than groups A and B (all P<0.05 or 0.01). All the 3 groups predominantly favored "no change" in training intensities. Conclusions:Pilots of different aircraft types generally meet the requirements of the current physical training programs. However, the frequency of physical training for pilots (cadets) requires more rigorous supervision. Flying cadets can adaptively engage in targeted training programs. Pilots of fighters, fighter bombers and advanced trainers should care about the intensity of aerobic training while giving more weight to load resistance physical training. Pilots of other types of aircraft should devote more effort to core training programs.

Objective To develop an erythrocyte-based delivery system for butyrylcholinesterase(BChE)that is capable of prophylaxis against organophosphorus nerve agents.Methods Recombinant BChE was produced and analyzed for oligomerization via polyacrylamide gel electrophoresis(PAGE)and Western blotting.A modified hypotonic preswelling method was employed to prepare BChE-loaded erythrocytes.The drug loading capacity and encapsulation efficiency were quantified using enzyme-linked immunosorbent assay(ELISA).Catalytic activity was assessed in vitro with an activity detection kit.The system was characterized via scanning electron microscopy(SEM),flow cytometry and a hematology analyzer.Results Recombinant BChE predominantly existed as dimers(85％dimer,15％monomer).The optimized volume ratio of erythrocytes to hypotonic solution was determined as 1:7.Compared with native and empty erythrocytes,BChE-loaded erythrocytes exhibited significantly higher catalytic activity(P＜0.001).The mean corpuscular volume of BChE-loaded erythrocytes increased(P＜0.001),while the mean content of corpuscular hemoglobin and hemoglobin in erythrocytes per 100 mL decreased(P＜0.001).SEM revealed no morphological differences(biconcave disc shape).Hypotonic preswelling moderately increased erythrocyte apoptosis(P＜0.001),but no statistical difference was observed between BChE-loaded and hypotonic-treated erythrocytes(P＞0.05).CD47 expression remained unchanged compared to native erythrocytes(P＞0.05).Conclusion The modified hypotonic preswelling method can generate BChE-loaded erythrocytes that retain the characteristics of native erythrocytes while conferring catalytic activity,offering a novel strategy for clinical intervention against organophosphorus poisoning.

S-methyl-L-cysteine sulfoxide (SMCO) is a non-protein sulfur-containing amino acid with a variety of functions. There are few reports on the enzymes catalyzing the biosynthesis of SMCO from S-methyl-L-cysteine (SMC). In this study, the flavin-containing monooxygenase gene derived from Schizosaccharomyces pombe (spfmo) was heterologously expressed in Escherichia coli BL21(DE3) and the enzymatic properties of the expressed protein were analyzed. The optimum catalytic conditions of the recombinant SpFMO were 30 ℃ and pH 8.0, under which the enzyme activity reached 72.77 U/g. An appropriate amount of Mg²⁺ improved the enzyme activity. The enzyme kinetic analysis showed that the K_m and k_cat/K_m of SpFMO on the substrate SMC were 23.89 μmol/L and 61.71 L/(min·mmol), respectively. Under the optimal reaction conditions, the yield of SMCO synthesized from SMC catalyzed by SpFMO was 12.31% within 9 h. This study provides reference for the enzymatic synthesis of SMCO.
Schizosaccharomyces/genetics* ; Escherichia coli/metabolism* ; Recombinant Proteins/metabolism* ; Cysteine/biosynthesis* ; Mixed Function Oxygenases/metabolism* ; Schizosaccharomyces pombe Proteins/metabolism* ; Oxygenases/metabolism* ; Kinetics

Objective To investigate the feasibility of the spatiotemporal filtering model in analysis of reported schistosomiasis cases, so as to provide insights into analysis of complicated data pertaining to schistosomiasis control. Methods Demographic and epidemiological data of reported schistosomiasis cases in Anhui Province from 1997 to 2010 were collected from Anhui Provincial Center for Disease Control and Prevention, and the annual prevalence of Schistosoma japonicum human infections was calculated. The meteorological data were captured from meteorological stations in counties (cities, districts) of Anhui Province where schistosomiasis cases were reported from 1997 to 2010 at the National Meteorological Information Center, including monthly average air temperature and precipitation. Meteorological data were interpolated using the inverse-distance weighting method, and the annual average air temperature and annual precipitation were calculated in each county (city, district). The centroid of the county (city, district) where schistosomiasis cases were reported was extracted using the software ArcGIS 10.0, and the Euclidean distance from each centroid to the Yangtze River was calculated as the distance between that county (city, district) and the Yangtze River. The global Moran’s I of the prevalence of S. japonicum human infections in Anhui Province for each year from 1997 to 2010 were calculated to analyze the spatial autocorrelation. A spatial weight matrix was constructed using Rook adjacency, and a first-order temporal weight matrix was built to quantify the relationship between disease changes over time. Subsequently, a spatiotemporal structure matrix was constructed. A negative binomial model was built based on the spatiotemporal structure matrix and data pertaining to reported schistosomiasis cases, and a linear model was created between the residual of the model and candidate set feature vectors to determine the optimal subset composition of the spatiotemporal filter through stepwise regression. Then, a spatio-temporal filtering model was constructed using the negative binomial model. Negative binomial models, Bayesian spatial models, and Bayesian spatiotemporal models were constructed and compared with the spatiotemporal filtering model to validate the performance of the spatiotemporal filtering model, and cross-validation was conducted for each model. The goodness of fit was evaluated using the deviance information criterion (DIC) and Watanabe-Akaike information criterion (WAIC), and the effectiveness of model validation was assessed using mean squared error (MSE), while the accuracy of assessment results was assessed using coefficients and their 95% confidence intervals (CI), and the computational efficiency was assessed based on the running time of the model. The four feature vectors with the largest Moran’s I values were selected to identify regions with autocorrelation through their schematic diagrams to investigate the differences in spatiotemporal patterns of specific regions. Results Of all models created, the spatiotemporal filtering model exhibited the highest goodness of fit (DIC = 3 240.70, WAIC = 3 257.80), the best model validation effectiveness (MSE = 42 617.52), and the runtime was 3.18 s, exhibiting the optimal performance. Across all modeling results, the distance from the Yangtze River showed a negative correlation with the number of reported schistosomiasis cases (coefficient values = −4.93 to −3.78, none of the 95% CIs included 0), and annual average air temperature or average precipitation posed no significant effects on numbers of reported schistosomiasis cases (both of the 95% CIs included 0). Schematic diagrams of feature vectors showed that the transmission of schistosomiasis might be associated with water systems in Anhui Province, and localized clustering patterns were primarily concentrated in the northern and western parts of schistosomiasis-endemic areas in the province. Conclusion The spatiotemporal filtering model is an effective spatiotemporal analysis characterized by simple modeling, user-friendly operation, accurate results and good flexibility, which may serve as an efficient alternative to conventional complex spatiotemporal models for data analysis in schistosomiasis researches.

Objective To explore the effectiveness and safety of polyglycolic acid(PGA)and hydroxypropyl methylcellulose(HPMC)composite materials for suturing after canine sleeve gastrectomy.Methods A total of 36 healthy Beagle dogs were randomly divided into experimental group and control group in a 1∶1 male-to-female ratio.The experimental group underwent gastric sleeve resection with PGA+HPMC composite material for suture reinforcement,while the control group used NV-ET-M60E-2 suture material.Postoperative monitoring included survival status,food intake,and body temperature changes.Venous blood samples were collected before surgery,3 days after surgery,and before euthanasia for routine blood tests.At 2,4,and 8 weeks postoperatively,six dogs were euthanized at each time point for histological examination,hard tissue pathological evaluation,and safety assessment of the heart,liver,spleen,lungs,and kidneys.Results There were no significant differences in blood routine test results between the control group and the experimental group(P＞0.05).Before dissection,the percentage of basophils was significantly higher in the control group than in the experimental group(P=0.015).At 2 weeks after surgery,the severity of liver cell edema in the control group was higher than in the experimental group(P=0.036).However,the two groups did not significantly differ in the histological examination results of the heart,liver,spleen,lungs,or kidneys at other time points(P＞0.05).Hard tissue pathological slice results at 2,4,and 8 weeks after surgery showed no material residue in either group by the 8th week,and there were no significant differences in inflammation and necrosis scores or fibrosis/fat infiltration totals between the two groups(P＞0.05).Inflammation scores and fibrosis/fat infiltration totals at 8 weeks post-operation were significantly lower than those at 2 weeks post-operation(P＜0.05).During the experiment,no near-death phenomena occurred in either group,and no fever or refusal to eat was observed within 3 days after surgery.At dissection,the Beagle dogs appeared normal with glossy fur and no abnormal secretions.Conclusion PGA+HPMC composite materials can be effectively degraded and used as non-toxic suture fixation materials for wound suturing after sleeve gastrectomy,providing a theoretical basis for their clinical application.

Diabetic retinopathy (DR) has long been recognized as a primary microvasculopathy disease.However, more and more studies have proved that diabetic retinal neurodegeneration (DRN) occurs in the early stage of DR, and may precede microvascular disease.Nevertheless, the association between vasculopathy and neuropathy remains unclear.Reduced contrast sensitivity, localized deficits in visual field, electrophysiological changes and thinning of retinal thickness on optical coherence tomography can occur in the early stage of DRN, the main pathological changes for those abnormalities are increased apoptosis of ganglion cells and increased reactivity of glial cells.The imbalance between pro-apoptotic molecules (such as glutamate, angiotensin Ⅱ, etc.) and neuroprotective molecules (such as pigment epithelium-derived factor, somatostatin, etc.), inflammation, and oxidative stress in retinal neurons are important causes of DRN.Strategies for treating neurodegeneration include reducing the production of anti-apoptotic molecules, inhibiting the apoptosis pathway of nerve cells, and using antioxidants and neuroprotective factors.Studies on neurodegeneration have found that early intervention can effectively control the progression of neurodegeneration and prevent the progression of DR in animal models, but there are currently few drugs available for clinical trials.Further research is needed to discover the link between vascular dysfunction and DRN and to evaluate neuroprotective agents for retinal neurodegeneration to develop effective strategies for preventing DR and delaying its progression.This article reviews the clinical detection methods, pathological mechanisms, and intervention strategies of DRN.

Objective To explore the effectiveness and safety of polyglycolic acid(PGA)and hydroxypropyl methylcellulose(HPMC)composite materials for suturing after canine sleeve gastrectomy.Methods A total of 36 healthy Beagle dogs were randomly divided into experimental group and control group in a 1∶1 male-to-female ratio.The experimental group underwent gastric sleeve resection with PGA+HPMC composite material for suture reinforcement,while the control group used NV-ET-M60E-2 suture material.Postoperative monitoring included survival status,food intake,and body temperature changes.Venous blood samples were collected before surgery,3 days after surgery,and before euthanasia for routine blood tests.At 2,4,and 8 weeks postoperatively,six dogs were euthanized at each time point for histological examination,hard tissue pathological evaluation,and safety assessment of the heart,liver,spleen,lungs,and kidneys.Results There were no significant differences in blood routine test results between the control group and the experimental group(P＞0.05).Before dissection,the percentage of basophils was significantly higher in the control group than in the experimental group(P=0.015).At 2 weeks after surgery,the severity of liver cell edema in the control group was higher than in the experimental group(P=0.036).However,the two groups did not significantly differ in the histological examination results of the heart,liver,spleen,lungs,or kidneys at other time points(P＞0.05).Hard tissue pathological slice results at 2,4,and 8 weeks after surgery showed no material residue in either group by the 8th week,and there were no significant differences in inflammation and necrosis scores or fibrosis/fat infiltration totals between the two groups(P＞0.05).Inflammation scores and fibrosis/fat infiltration totals at 8 weeks post-operation were significantly lower than those at 2 weeks post-operation(P＜0.05).During the experiment,no near-death phenomena occurred in either group,and no fever or refusal to eat was observed within 3 days after surgery.At dissection,the Beagle dogs appeared normal with glossy fur and no abnormal secretions.Conclusion PGA+HPMC composite materials can be effectively degraded and used as non-toxic suture fixation materials for wound suturing after sleeve gastrectomy,providing a theoretical basis for their clinical application.