BACKGROUND:The most common complication of traumatic femoral neck fractures after internal fixation is femoral head necrosis.Currently,many studies have reported on the risk factors that affect the occurrence and development of postoperative femoral head necrosis,but there is still a lack of tools to predict the risk of femoral head necrosis after internal fixation of femoral neck fractures.OBJECTIVE:To develop a predictive model that estimates the risk of femoral head necrosis shortly after patients with femoral neck fractures receive cannulated screw internal fixation.METHODS:A retrospective analysis reviewed clinical records of 172 patients who underwent cannulated screw internal fixation for femoral neck fractures at Department of Orthopedics of Mianyang Central Hospital from January 2013 to June 2023.Patients were categorized into two groups based on the presence or absence of femoral head necrosis within one year post-operation:the necrosis group and the non-necrosis group.Univariate analysis,Lasso regression,and multivariate Logistic regression techniques were employed to identify the determinants of femoral head necrosis.A nomogram prediction model was constructed using R language's"rms"package,version 4.0.The receiver operating characteristic curve was used to evaluate the discriminatory ability of the model.The Hosmer-Lemeshow test was used to evaluate the goodness of fit of the model,and the decision curve analysis was used to determine its clinical application benefits.Internal validation of the study was conducted using the Bootstrap method,involving 1 000 repeated samplings.To delve deeper into the primary factors influencing femoral head necrosis post-internal fixation of the femoral neck,this paper employed the SHAP method for data set analysis.RESULTS AND CONCLUSION:(1)The risk factors leading to femoral head necrosis in the short term after cannulated screw fixation of femoral neck fractures include:smoking,diabetes,Garden classification,fracture line location,reduction quality,age,and operation time.(2)The prediction model demonstrated robust performance,evidenced by an area under the curve of 0.940(95％Confidence Interval:0.903 to 0.977),indicating a high level of prediction accuracy.The model achieved a sensitivity of 90.2％and a specificity of 87.6％,indicating that its diagnostic performance was stable.The Hosmer-Lemeshow goodness-of-fit test yielded a chi-square value of 6.593 with a P-value of 0.581,confirming that the model's predictions closely align with the observed outcomes.(3)The calibration curve of the model also performed well,and its overall trend was very close to the ideal curve,further proving the high accuracy of the model.(4)The internal validation was carried out by the Bootstrap method with 1 000 repeated samplings,and the area under the curve of the model internal validation was still as high as 0.939,proving that the model had good stability.(5)Through the decision curve,it is found that within the probability threshold range of 1％to 92％,the model can obtain the maximum net benefit value.(6)The SHAP analysis results show that among the risk factors analyzed in this study,the location of the fracture line serves as the most significant predictor of femoral head necrosis following internal fixation with cannulated screws in femoral neck fractures,and subcapital fractures are extremely prone to femoral head necrosis after surgery.(7)It is concluded that the validated prediction model demonstrates strong discriminative power and reliability,offering practical clinical utility.It serves as a useful reference tool for short-term risk assessment of femoral head necrosis following internal fixation of femoral neck fractures.

BACKGROUND:The most common complication of traumatic femoral neck fractures after internal fixation is femoral head necrosis.Currently,many studies have reported on the risk factors that affect the occurrence and development of postoperative femoral head necrosis,but there is still a lack of tools to predict the risk of femoral head necrosis after internal fixation of femoral neck fractures.OBJECTIVE:To develop a predictive model that estimates the risk of femoral head necrosis shortly after patients with femoral neck fractures receive cannulated screw internal fixation.METHODS:A retrospective analysis reviewed clinical records of 172 patients who underwent cannulated screw internal fixation for femoral neck fractures at Department of Orthopedics of Mianyang Central Hospital from January 2013 to June 2023.Patients were categorized into two groups based on the presence or absence of femoral head necrosis within one year post-operation:the necrosis group and the non-necrosis group.Univariate analysis,Lasso regression,and multivariate Logistic regression techniques were employed to identify the determinants of femoral head necrosis.A nomogram prediction model was constructed using R language's"rms"package,version 4.0.The receiver operating characteristic curve was used to evaluate the discriminatory ability of the model.The Hosmer-Lemeshow test was used to evaluate the goodness of fit of the model,and the decision curve analysis was used to determine its clinical application benefits.Internal validation of the study was conducted using the Bootstrap method,involving 1 000 repeated samplings.To delve deeper into the primary factors influencing femoral head necrosis post-internal fixation of the femoral neck,this paper employed the SHAP method for data set analysis.RESULTS AND CONCLUSION:(1)The risk factors leading to femoral head necrosis in the short term after cannulated screw fixation of femoral neck fractures include:smoking,diabetes,Garden classification,fracture line location,reduction quality,age,and operation time.(2)The prediction model demonstrated robust performance,evidenced by an area under the curve of 0.940(95％Confidence Interval:0.903 to 0.977),indicating a high level of prediction accuracy.The model achieved a sensitivity of 90.2％and a specificity of 87.6％,indicating that its diagnostic performance was stable.The Hosmer-Lemeshow goodness-of-fit test yielded a chi-square value of 6.593 with a P-value of 0.581,confirming that the model's predictions closely align with the observed outcomes.(3)The calibration curve of the model also performed well,and its overall trend was very close to the ideal curve,further proving the high accuracy of the model.(4)The internal validation was carried out by the Bootstrap method with 1 000 repeated samplings,and the area under the curve of the model internal validation was still as high as 0.939,proving that the model had good stability.(5)Through the decision curve,it is found that within the probability threshold range of 1％to 92％,the model can obtain the maximum net benefit value.(6)The SHAP analysis results show that among the risk factors analyzed in this study,the location of the fracture line serves as the most significant predictor of femoral head necrosis following internal fixation with cannulated screws in femoral neck fractures,and subcapital fractures are extremely prone to femoral head necrosis after surgery.(7)It is concluded that the validated prediction model demonstrates strong discriminative power and reliability,offering practical clinical utility.It serves as a useful reference tool for short-term risk assessment of femoral head necrosis following internal fixation of femoral neck fractures.

ObjectiveGastric hemorrhage is one of the most common and life-threatening emergencies of the upper digestive tract. Early identification and continuous monitoring are essential for reducing rebleeding rates and mortality, particularly within the critical early hours after onset. Although endoscopy and radiological imaging can accurately localize bleeding sites, these approaches are invasive, resource-intensive, and unsuitable for continuous bedside monitoring. Electrical impedance tomography (EIT), as a noninvasive and radiation-free functional imaging technique, offers real-time visualization of conductivity distribution and has the potential for detecting intragastric bleeding based on the electrical contrast between blood and surrounding gastric tissues. In this study, a three-dimensional gastric EIT (3D-gEIT) framework is proposed to achieve noninvasive, real-time, and dynamic monitoring of gastric hemorrhage, with emphasis on spatial localization and quantitative volume assessment. MethodsA three-dimensional upper-abdominal simulation model incorporating the stomach, gastric wall, gastric contents, and surrounding tissues was established. Three electrode configurations, namely the dual layer ring, the four layer staggered ring, and the opposed dual plane array, were designed and systematically compared to evaluate their influence on depth sensitivity and spatial resolution. Based on the Tikhonov-Noser hybrid regularization scheme, a region-clustering constraint was introduced to develop the TK-Noser-RCC algorithm. This approach aggregates spatially adjacent elements with similar conductivity variations, thereby enhancing structural continuity and suppressing isolated noise artifacts. To validate the proposed framework, an upper-abdominal physical phantom was constructed using agar to simulate background tissue conductivity. Hemispherical high-conductivity inclusions with volumes ranging from 10 ml to 50 ml were attached to the inner gastric wall to mimic localized bleeding under different gastric filling states. Boundary voltages were acquired under a 120 kHz excitation current and reconstructed using the TK-Noser-RCC algorithm. Furthermore, an in vivo animal experiment was performed using a porcine model with adult-scale abdominal dimensions. A total of 100 ml of autologous blood was injected incrementally into the stomach to simulate progressive gastric hemorrhage, and time-difference EIT reconstruction was conducted at each injection stage to assess the dynamic system response under physiological conditions. ResultsSimulation results demonstrated that the opposed dual-plane electrode array achieved superior depth sensitivity distribution and spatial resolution. For a 40 ml hemorrhage model, the average ICC and SSIM improved by 55.9% and 38.8% compared with the dual-layer ring configuration, and by 64.0% and 39.5% compared with the four-layer staggered configuration. The proposed region-clustering constraint significantly enhanced reconstruction stability. Under added Gaussian noise of 40 dB and 30 dB, ICC values remained approximately 0.85, indicating effective artifact suppression and preservation of boundary integrity. In physical phantom experiments, reconstructed hemorrhage volumes increased approximately linearly with the preset hemispherical volumes, and the reconstructed high-conductivity regions closely matched the actual bleeding locations. Both empty-stomach and full-stomach conditions were evaluated, demonstrating that the opposed dual-plane configuration maintained stable imaging performance across varying gastric contents. In the animal experiment, reconstructed low-impedance regions expanded progressively with increasing injected blood volume. The spatial localization of the hemorrhage remained stable throughout the procedure, and no significant artifacts were observed. Quantitative analysis showed that reconstructed volume and average conductivity variation exhibited an approximately linear growth trend with injected blood volume, confirming the sensitivity of the system to dynamic intragastric conductivity changes. ConclusionThe proposed 3D-gEIT framework enables quantitative reconstruction of gastric hemorrhage volume and spatial distribution with improved depth sensitivity, structural continuity, and noise robustness compared with conventional EIT approaches. By integrating optimized electrode configuration and a region-clustering-constrained reconstruction algorithm, the system provides stable dynamic monitoring under both controlled phantom conditions and in vivo physiological environments. This method offers a noninvasive, real-time, and low-cost imaging strategy for early diagnosis, postoperative monitoring, and bedside surveillance of gastric bleeding.

Objective To design a high altitude adaptive oxygen generator for the crews to alleviate their high altitude reaction in high altitude environment and meet their requirements for oxygen supply.Methods A high altitude adaptive oxygen generator based on the mature pressure swing adsorption oxygen production method was designed with the key technologies of discharge capacity compensation of air compression pump and airway fusion of molecular sieve tower,which had the components of molecular sieve tower,air compression pump,controller,cooling fan,cooler,solenoid valve,regulator,flow meter and etc.Trials were carried out at the simulated altitude and field plateau environment so as to verify the high altitude adaptive performance of the oxygen generator developed.Results The trial results showed the oxygen generator met the desired objectives and the requirements for oxygen volume fraction in GJB 2799-1996 General specification for medical oxygen generator using molecular sieve method.Conclusion The oxygen generartor provides oxygen supply effectively for vehicle operators in plateau environments or the ones rushing into the plateau.[Chinese Medical Equipment Journal,2025,46(4):29-34]

Objective To summarize the clinical features,treatment and prognosis of patients with primary central nervous system lymphoma(PCNSL)with clonal bone marrow B cells,and to explore the influence on clinical diagnosis and treatment.Methods PCNSL patients with clonal bone marrow B cells diagnosed by flow cytometry between Jan 2020 and Jul 2023 at Huashan Hospital of Fudan University were enrolled.The auxiliary examination data of these patients were collected,including complete blood count,routine biochemistry,bone marrow aspiration and biopsy,contrast-enhanced brain MRI,and whole-body PET-CT.Kaplan-Meier was used to draw the survival curve,and relevant literature was reviewed.Results A total of 223 newly diagnosed PCNSL patients were included,187 of whom completed bone marrow puncture and biopsy evaluation.We found clonal bone marrow B cells in 16 of 187 cases(8.56%)by flow cytometry.2 patients showed B lymphoma involving the bone marrow.All patients received a high-dose methotrexate based chemotherapy.The median progression free survival(PFS)of 16 patients with clonal bone marrow B cells was 11.1 months,and the median PFS of 171 patients with normal bone marrow was 12.6 months.There was no significant difference in the PFS between the two groups.Conclusion PCNSL with clonal bone marrow B cells had no specific clinical features,but bone marrow flow cytometry showed clonal B cells.High-dose methotrexate treatment regimen is effective.There was no significant difference in PFS for PCNSL patients with clonal B cells and normal findings in bone marrow.Clonal B cells in bone marrow may be caused by monoclonal B-cell lymphocytosis(MBL),lymphoma involves the bone marrow and the presence of common precursor cells.Bone marrow examination should be performed in the initial evaluation of suspected PCNSL.

A quadruplex RT-qPCR method was developed for rapid identification and diagnosis of transmissible gastroenteritis virus(TGEV)of swine,porcine epidemic diarrhea virus(PEDV),porcine deltacorona virus(PDCoV),and porcine rotavirus type A(PoRVA).The full-length sequences of PEDV(77 strains),TGEV(63 strains),PDCoV(17 strains)that are prevalent in China,as well as the 85 VP6 gene sequences of PoRVA,were downloaded from the NCBI database for homology analysis.Based on the relatively conserved sequences,the corresponding primers and probes for each virus were designed and used to establish the quadruplex RT-qPCR method.After optimization of the probes and the reaction conditions,the specificity,sensitivity,and repeatability were determined.Using the established method,109 clinical samples of diarrhea were tested and further compared with the results by standard method.The results showed that the quadruplex RT-qPCR method established in this experiment has good amplification effect,with the C,value linearly correlated with the copies of templates(R2＞0.99).Specificity assay demonstrated that the quadruplex RT-qPCR method can identify TGEV,PEDV,PDCoV,PRoVA strains,and do not de-tect African swine fever virus(ASFV),porcine circovirus type 2(PCV2),porcine reproductive and respiratory syndrome virus(PRRSV),classical swine fever virus(CSFV),pseudorabies virus(PRV)and other epidemic viruses.Sensitivity assay showed that the detection limits for TGEV,PEDV,PDCoV and PoRVA were 10,20,20 and 50 copies/μL,respectively.The method exhibits excellent reproducibility,with coefficients of variation(Cv)for both intra-and inter-assay repli-cates being less than 1％.Detection of 109 samples of diarrhea by this method yielded the coinci-dence rate of 100％with the industry standard,indicating high practical applicability.The devel-oped method possesses the advantages of strong strain compatibility,high sensitivity,strong speci-ficity,good repeatability and stability.It is suitable for virus diagnosis and large-scale clinical sam-ple testing,providing technical support for disease prevention and control as well as epidemiologi-cal investigation.

A quadruplex RT-qPCR method was developed for rapid identification and diagnosis of transmissible gastroenteritis virus(TGEV)of swine,porcine epidemic diarrhea virus(PEDV),porcine deltacorona virus(PDCoV),and porcine rotavirus type A(PoRVA).The full-length sequences of PEDV(77 strains),TGEV(63 strains),PDCoV(17 strains)that are prevalent in China,as well as the 85 VP6 gene sequences of PoRVA,were downloaded from the NCBI database for homology analysis.Based on the relatively conserved sequences,the corresponding primers and probes for each virus were designed and used to establish the quadruplex RT-qPCR method.After optimization of the probes and the reaction conditions,the specificity,sensitivity,and repeatability were determined.Using the established method,109 clinical samples of diarrhea were tested and further compared with the results by standard method.The results showed that the quadruplex RT-qPCR method established in this experiment has good amplification effect,with the C,value linearly correlated with the copies of templates(R2＞0.99).Specificity assay demonstrated that the quadruplex RT-qPCR method can identify TGEV,PEDV,PDCoV,PRoVA strains,and do not de-tect African swine fever virus(ASFV),porcine circovirus type 2(PCV2),porcine reproductive and respiratory syndrome virus(PRRSV),classical swine fever virus(CSFV),pseudorabies virus(PRV)and other epidemic viruses.Sensitivity assay showed that the detection limits for TGEV,PEDV,PDCoV and PoRVA were 10,20,20 and 50 copies/μL,respectively.The method exhibits excellent reproducibility,with coefficients of variation(Cv)for both intra-and inter-assay repli-cates being less than 1％.Detection of 109 samples of diarrhea by this method yielded the coinci-dence rate of 100％with the industry standard,indicating high practical applicability.The devel-oped method possesses the advantages of strong strain compatibility,high sensitivity,strong speci-ficity,good repeatability and stability.It is suitable for virus diagnosis and large-scale clinical sam-ple testing,providing technical support for disease prevention and control as well as epidemiologi-cal investigation.

Objective:To compare the safety, number of lymph nodes removed, rate of lymph node metastasis, and prognosis between proximal gastrectomy (PG) and total gastrectomy (TG) in patients with Siewert types II and III adenocarcinoma of the esophagogastric junction.Methods:In this retrospective cohort study, clinical data of patients diagnosed with adenocarcinoma of the esophagogastric junction at Changzhi People's Hospital, affiliated with Changzhi Medical College, between December 2019 and November 2022, were collected. Patients who had received neoadjuvant therapy, had multiple malignant lesions in the stomach, had concomitant malignancies in other organs, had incomplete clinical data, or had been lost to follow-up were excluded. The study cohort comprised 308 patients, 99 in the PG group and 209 in the TG group. To reduce confounding bias, propensity score matching was performed, matching patients for age, sex, body mass index, tumor diameter, and pathological stage in a 1:1 ratio, resulting in 73 patients in each group. The primary outcomes assessed were operative details, number of lymph nodes dissected, rate of lymph node metastasis, postoperative complications, duration of hospital stay, and follow-up and survival outcomes.Results:The PG group had a significantly shorter median operative time than did the TG group (250 vs. 280 minutes, Z = -4.970, P<0.001), with fewer cases of intraoperative blood loss >100 mL (30.1%[22/73] vs. 46.6%[34/73], χ2=4.171, P=0.041), and a smaller number of lymph nodes removed (median 33 vs. 46, Z =-4.774, P<0.001); all of these differences are statistically significant (all P<0.05). Differences between the two groups in postoperative hospital stay and postoperative complications were not statistically significant (both P>0.05). Furthermore, no statistically significant differences were found between the PG and TG groups in the number of lymph nodes dissected or the lymph node metastasis rates at stations No. 1, No. 2, No. 3, No. 4sa, No. 4sb, and No. 7 (all P> 0.05). Among the 209 patients in the TG group, analysis of risk factors for metastasis to distal perigastric lymph nodes (No.4d, No.5, and No.6) showed that patients with tumor diameters ≤4 cm and T1–T3 stage disease had significantly lower rates of metastasis to these lymph nodes than did patients with tumor diameters >4 cm and/or T4 stage disease (0/78 vs. 12/131 [9.2%]); these differences are statistically significant ( P=0.014). The median duration of follow-up for the entire cohort was 26 months. The 3-year overall survival rates for the PG and TG groups were 62.5% and 63.3%, respectively; this difference is not statistically significant (χ 2=0.330, P = 0.565). Multivariate analysis showed that older age ( P = 0.035) and advanced pathological stage ( P = 0.018) were significant independent risk factors that affected overall survival in patients with Siewert type II and III adenocarcinoma of the esophagogastric junction. Conclusions:PG is safe and feasible for patients with Siewert types II and III adenocarcinoma of the esophagogastric junction. The number of lymph nodes dissected and metastasis status were similar in the TG and PG groups.

The objective of this study was to develop a rapid and precise detection technique for por-cine Senecavirus A(SVA)employing reverse transcription recombinase polymerase amplification(RT-RAA)in conjunction with CRISPR Cas13a technology.Additionally,the study aimed to opti-mize the assay's reaction conditions to enhance amplification efficiency.Eight RT-RAA primer sets were designed based on the conserved gene sequence of porcine SVA,and a series of reaction condi-tions were evaluated to refine the RT-RAA reaction system.Subsequently,CRISPR-derived RNA(crRNA)sequences were developed and selected to construct the RT-RAA-CRISPR reaction sys-tem.The method's specificity was determined by examining six prevalent porcine pathogenic nucleic acids,while its sensitivity was assessed using SVA cRNA standards quantified by digital PCR.The method's stability and the consistency of clinical sample analysis were also evaluated.The findings revealed that the optimized RT-RAA and CRISPR reaction systems exhibited the highest amplifi-cation efficiency at a reaction temperature of 37 ℃.Among the eight crRNAs,five were identified as exhibiting the strongest detection signals.The formulated RT-RAA-CRISPR Cas13a method demonstrated exceptional specificity,showing no cross-reactivity with other common porcine disea-ses,including ASFV,PRRSV,PEDV,PCV2,CSFV,and PRV.The method achieved high sensitivi-ty,detecting as low as 0.86 copies/μL of SVA,and exhibited stable fluorescence output,robust re-producibility,and the ability to complete clinical sample analysis within 50 minutes.Consistency e-valuation with six positive and 58 negative samples indicated 100％agreement in outcomes.These results substantiate that the study successfully established a rapid and specific RT-RAA-CRISPR Cas13a detection method for the on-site identification of porcine Senecavirus A,demonstrating high specificity and sensitivity,and holds promise for application in SVA monitoring and control initia-tives.

Objective To design a high altitude adaptive oxygen generator for the crews to alleviate their high altitude reaction in high altitude environment and meet their requirements for oxygen supply.Methods A high altitude adaptive oxygen generator based on the mature pressure swing adsorption oxygen production method was designed with the key technologies of discharge capacity compensation of air compression pump and airway fusion of molecular sieve tower,which had the components of molecular sieve tower,air compression pump,controller,cooling fan,cooler,solenoid valve,regulator,flow meter and etc.Trials were carried out at the simulated altitude and field plateau environment so as to verify the high altitude adaptive performance of the oxygen generator developed.Results The trial results showed the oxygen generator met the desired objectives and the requirements for oxygen volume fraction in GJB 2799-1996 General specification for medical oxygen generator using molecular sieve method.Conclusion The oxygen generartor provides oxygen supply effectively for vehicle operators in plateau environments or the ones rushing into the plateau.[Chinese Medical Equipment Journal,2025,46(4):29-34]