The nuclear magnetic resonance (NMR) thermal control subsystem described in this paper is a newly developed platform-based thermal management solution. It presents critical challenges in system architecture design and core component selection. Therefore, it is necessary to carry out sufficient reliability design and verification work in the design and development stage to ensure its high quality and high reliability. Firstly, based on the statistical and analytical calculation of the client installation data of the benchmark product, the reliability metric of the new research subsystem is determined, and its usage and environmental profile are defined. Secondly, for the reliability metric to be verified, the test based on reliability growth and reliability demonstration is planned and implemented. A customized test platform is built, relevant reliability test parameters are designed, and a long-term test monitoring and recording mechanism is established to ensure the high-quality implementation of reliability tests. Finally, a detailed analysis is carried out on the design defects and failure modes exposed during the reliability test, and corresponding control measures are proposed to achieve the engineering goal of improving product robustness throughout its life cycle.
Equipment Design ; Magnetic Resonance Spectroscopy/instrumentation* ; Reproducibility of Results

Objective Exploring the diagnostic value of T-cell enzyme-linked immunospot assay(T-SPOT.TB)combined with rifampicin-resistant Mycobacterium tuberculosis real-time fluorescence quantitative nucleic acid ampli-fication detection(XpertMTB/RIF)in geriatric AIDS patients with Mycobacterium tuberculosis(MTB)infection.Methods From May 2022 to May 2024,86 elderly patients with AIDS suspected MTB in Hengshui Third People's Hospital were gathered and separated into AIDS complicated with MTB(research group)and AIDS without MTB(control group)according to the pathological examination results.MTB culture,T-SPOT.TB and XpertMTB/RIF were performed.Kappa analysis was applied to evaluate the consistency between T-SPOT.TB combined with Xpert-MTB/RIF and the gold standard for diagnosing MTB coinfection in AIDS patients.ROC curve and four grid table were plotted to analyze the value of the combination of T-SPOT.TB and XpertMTB/RIF in the diagnosis of AIDS complicated with MTB infection.Results The blood γ-interferon,the positive detection rates of T-SPOT.TB and XpertMTB/RIF in the research group were higher than those in the control group(P＜0.05).The AUC of T-SPOT.TB in diagnosing AIDS with MTB infection was 0.810,that of Xpert MTB/RIF in diagnosing AIDS with MTB infection was 0.835,and the AUC of the two in diagnosing AIDS with MTB infection was 0.910.The Kappa values of T-SPOT.TB,Xpert MTB/RIF and their combined diagnosis for AIDS with MTB infection were 0.624,0.674 and 0.825,respectively.The accuracy of T-SPOT.TB in the diagnosis of AIDS with MTB was 82.56%,the accuracy of XpertMTB/RIF in the diagnosis of AIDS with MTB was 84.88%,and the accuracy of the combined di-agnosis for AIDS with MTB was 91.86%.Conclusions T-SPOT.TB combined with XpertMTB/RIF can improve the accuracy of diagnosis of AIDS with MTB,and can be used as a clinical auxiliary diagnosis method for AIDS pa-tients complicated with MTB.

The monitoring unit used in the nuclear magnetic resonance system,as an important unit of the system,faces a high thermal risk during its entire life cycle.This paper ensures the high efficiency and reliability of the thermal design of the product module from the two dimensions of structural design and device derating design.In order to reduce the risk of thermal design of electronic modules and comprehensively verify the effectiveness of thermal design of electronic modules,the design verification is carried out by combining simulation and experiment.In the simulation process,by establishing a thermal simulation model at the circuit board level,the crustal temperature of the core device is numerically calculated,and the index is compared with the thermal design index value and the test value,on the one hand,to verify the correctness of the simulation model.On the other hand,the validity of thermal design is verified.In the testing process,a thermal test platform for product modules is built,and the thermal characteristics test values of the core components of the module under extreme electrical conditions are obtained,and the corresponding conversion methods are used to predict the thermal performance and thermal design margin of the product at different altitudes.The results show that the electronic module can meet the thermal design requirements in terms of structural design and derating design of core components,and can ensure that the product module can work safely and reliably during the entire life cycle of the NMR system.

Objective To construct nomogram models to predict the risk factors for early death in patients with metastatic melanoma(MM).Methods The study covered 2138 cases from the Surveillance,Epidemiology,and End Results Program(SEER)database and all these patients were diagnosed with MM between 2010 and 2015.Logistic regression was performed to identify independent risk factors affecting early death in MM patients.These risk factors were then used to construct nomograms of all-cause early death and cancer-specific early death.The efficacy of the model was assessed with receiver operating characteristic(ROC)curves,calibration curves,and decision curve analysis(DCA).In addition,external validation of the model was performed with clinicopathologic data of 105 patients diagnosed with MM at Sichuan Cancer Hospital between January 2015 and January 2020.Results According to the results of logistic regression,marital status,the primary site,N staging,surgery,chemotherapy,bone metastases,liver metastases,lung metastases,and brain metastases could be defined as independent predictive factors for early death.Based on these factors,2 nomograms were plotted to predict the risks of all-cause early death and cancer-specific early death,respectively.For the models for all-cause and cancer-specific early death,the areas under the curve(AUCs)for the training group were 0.751(95%confidence interval[CI]:0.726-0.776)and 0.740(95%CI:0.714-0.765),respectively.The AUCs for the internal validation group were 0.759(95%CI:0.722-0.797)and 0.757(95%CI:0.718-0.780),respectively,while the AUCs for the external validation group were 0.750(95%CI:0.649-0.850)and 0.741(95%CI:0.644-0.838),respectively.The calibration curves showed high agreement between the predicted and the observed probabilities.DCA analysis indicated high clinical application value of the models.Conclusion The nomogram models demonstrated good performance in predicting early death in MM patients and can be used to help clinical oncologists develop more individualized treatment strategies.

Objective: To investigate the mechanism of apoptosis of CD8⁺T lymphocyte in peripheral blood of patients with hepatocellular carcinoma (HCC). Methods: The proportion and apoptosis of peripheral blood CD8⁺T lymphocytes in 30 healthy controls, 30 patients with cirrhosis and 60 HCC patients were detected by Flow cytometry, and the expression of Fas on the surface of CD8⁺T lymphocytes was reported. The differences between groups were compared using independent sample t-test, and data of variance were tested with Mann-Whitney U non-parametric test, P < 0.05 was considered statistically significant. Results: The proportion of CD8⁺T lymphocytes in peripheral blood of patients with HCC was 26.4% ± 9.2%, higher than that of 24.5% ± 7.1% in cirrhosis (t = 0.783, P = 0.489), and and healthy control 19.7% ± 4.7% (t = 2.920, P = 0.004). The proportion of apoptotic CD8⁺T lymphocytes in peripheral blood of HCC patients was 25.3% ± 6.5%, of the total CD8⁺T lymphocytes, which was significantly higher than that of healthy controls 12.1%±6.5% (t = 7.555, P < 0.001) and cirrhotic 13.6% ± 5.8% (t = 5.213, P < 0.001), the differences were statistically significant. The proportion of Fas⁺CD8⁺T lymphocytes in the HCC group was 62.2% ± 18.5%, higher than that in the healthy control group 42.6%±16.5% (t = 4.127, P < 0.001) and 46.1% ± 14.5% (t = 2.561, P < 0.01)of the cirrhosis group, the differences were statistically significant. Fas expression was positively correlated with the apoptosis of CD8⁺T lymphocytes (r ² = 0.113, P < 0.05). Conclusion The proportion of CD8⁺T lymphocytes in peripheral blood of patients with HCC is higher than that of healthy controls, but the proportion of CD8⁺T lymphocyte apoptosis based on Fas/FasL pathway increased, which may be an important mechanism for tumor cell immune escape.

Objective To investigate the awareness rate of health knowledge,health behavior formation rate and psychological state before and after retirement intervention,analyse comprehensive psychological intervention and general psychological intervention to health behavior formation and improve the negative emotion in retired population.Methods By using cohort study method,206 retired people were randomly divided into comprehensive psychological intervention group (experimental group) and only given general psychological intervention group (control group),and each group included 103 cases.Comprehensive psychological intervention group were given health behavior and cognitive intervention,psychological intervention,psychological intervention in general family and social family care intervention,and the control group was given healthy behavior and cognitive intervention,psychological intervention.The staff were treated within 1 weeks of first assessment,2 weeks after the second assessment,4 weeks after the final.Health behavior was surveyed by Ministry of finance,the Ministry of health on public health subsidies special funds notice in city community health education pilot project in the questionnaire.Health status and quality of life were assessed with the family APGAR index (APGAR).Mental state evaluation and assessment of the treatment effect by using Hamilton Depression Scale (HAMD),MBI index method was assessed with activities of daily living.The effect of the two groups were compared before and after the intervention of health knowledge rate and formation rate of different intervention methods and psychological state of health behavior.Results The results showed that there were no significant differences between experimental group and control group in age,sex,level of education and other social,and there was no significant difference in HAMD,MBI and APGAR scores at baseline.Through the implementation of the comprehensive of psychological intervention,subjects have varying degrees of improving the awareness rate of health knowledge,and the intervention group was significantly higher than the control group (P ＜ 0.05).The two group of healthy behavior of subjects in the chopping board monitoring,physical fitness,blood pressure to separate raw and cooked on such projects had different degrees of improvement,at the same time,although no intervention,in the monitoring of blood pressure.The control group increased compared with the baseline significantly (P＜ 0.05).Intervention group had significant difference in APGAR score increased (P＜ 0.05).HAMD score and MBI score decreased and the differences were statistically significant (P＜ 0.01),while the control group had no significant difference before and after intervention.Conclusion Comprehensive psychological intervention can significantly improve the rate of formation from the awareness rate of health knowledge and health behavior of retirees,and improve the state of negative emotions from retiree.

Objective To study the effects of soybean isoflavone(SI) on lipid peroxidation and liver ultrastructure in ovariectomized rats. Methods Seventy female Sprague-Dawley(SD) rats were randomly divided into 7 groups according to the levels of total cholesterol(TC) in serum: hyper-lipoid group,estrogen group,low-dose SI group,middle-dose SI group,high-dose SI group,sham group and normal control group.After bilateral ovaries were extirpated except sham and normal control groups for a week,the estrogen,different doses of SI or deionized water were fed with intragastric administration for 12 weeks.The rat body weight was weighted once per week and blood samples were collected at the time of ovariectomization,the 4th and 8th weeks after administeration at the time of being killed.The serum TC,triglyceride(TG),high or low density lipoprotein-cholesterol(HDL-C,LDL-C),lipoprotein(a) and antioxygen enzyme were assayed. Results LDL-C levels in SI intervention groups were significantly lower than that in hyper-lipoid groups but higher than that in normal control group;the levels of lipoprotein(a) were changed;there was almost no effect on HDL-C in serum.SI could retain integrity and ultrastructure of hepatocyte;there was similar structure in high dose SI group and normal control group.An obvious damage was detected in hyper-lipoid group.Conclusion SI can improve lipoprotein(a) and lipid peroxidation in ovariectomized rats.A continuous intervention with high-SI can reduce LDL-C to normal lever and retain integrity and ultrastructure of hepatocyte.