In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model wi...In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model with freezing/melting phase changes is developed for the heat transfer analysis of the soil.Based on the numerical solution of the model,the variation trends of underground soil temperature of the SGSHPS operated in various alternate operation modes are discussed.The results indicate that,for the day-night and short-time interval alternate operation modes without solar energy,the operation time fraction of a solar heat source should be confined to from 50% to 58% when operated in an alternate period of 24 h.Meanwhile,the disadvantages of a natural resumption of soil temperature can be overcome effectively by solar energy filling,and an optimal operation effect can be achieved by integrating the mode of solar energy filling with other alternate modes.In addition,the accuracy of the presented model is verified by the experimental data of borehole wall temperatures.The conclusions can provide a reference for the optimization operation of the SGSHPS.展开更多
A novel high-κ~ A1203/HfO2/AI203 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibit...A novel high-κ~ A1203/HfO2/AI203 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibits excellent program-erasable characteristics. A large memory window of ~4 V, a small leakage current density of ~2 ×10-6 Acre-2 at a gate voltage of 7V, a high charge trapping density of 1.42 × 1013 cm-2 at a working vo]tage of 4-10 V and good retention characteristics are observed. Furthermore, the programming （△ VFB = 2.8 V at 10 V for 10μs） and erasing speeds （△VFB =-1.7 V at -10 V for 10μs） of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-κ Al2O3/HfO2/Al2O3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.展开更多
We propose and investigate a novel metal/SiO_2/Si_3N_4/SiO_2/SiGe charge trapping flash memory structure（named as MONOS）, utilizing Si Ge as the buried channel. The fabricated memory device demonstrates excellent pr...We propose and investigate a novel metal/SiO_2/Si_3N_4/SiO_2/SiGe charge trapping flash memory structure（named as MONOS）, utilizing Si Ge as the buried channel. The fabricated memory device demonstrates excellent programerasable characteristics attributed to the fact that more carriers are generated by the smaller bandgap of Si Ge during program/erase operations. A flat-band voltage shift 2.8 V can be obtained by programming at ＋11 V for 100 us. Meanwhile, the memory device exhibits a large memory window of ~7.17 V under ±12 V sweeping voltage, and a negligible charge loss of 18% after 104 s＇ retention. In addition, the leakage current density is lower than 2.52 × 10^（-7） A·cm^（-2） below a gate breakdown voltage of 12.5 V. Investigation of leakage current-voltage indicates that the Schottky emission is the predominant conduction mechanisms for leakage current. These desirable characteristics are ascribed to the higher trap density of the Si_3N_4 charge trapping layer and the better quality of the interface between the SiO_2 tunneling layer and the Si Ge buried channel. Therefore, the application of the Si Ge buried channel is very promising to construct 3 D charge trapping NAND flash devices with improved operation characteristics.展开更多
Loop heat pipes （LHPs） were designed for the alpha magnetic spectrometer （AMS-02） to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit （...Loop heat pipes （LHPs） were designed for the alpha magnetic spectrometer （AMS-02） to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit （-20℃） in cold environment. Extensive experiments were performed on operation characteristics of LHPs with the bypass valve for AMS-02 during thermal vacuum and thermal balance （TVTB） test. We found that the bypass valve can start up successfully in cold environment. With the bypass valve, the evaporator temperature is stable and can meet the requirement of the cryocooler. We analyzed three operating modes of the bypass valve. Set point temperature and regulation temperature shifts were observed and their relations with the bypass valve temperature were given.展开更多
This paper presents an experimental study including visualization on a flat plate closed loop pulsating heat pipes.It consists of a total of 40 channels with square cross section(2 mm×2 mm,165 mm long) machined d...This paper presents an experimental study including visualization on a flat plate closed loop pulsating heat pipes.It consists of a total of 40 channels with square cross section(2 mm×2 mm,165 mm long) machined directly on an aluminum plate(180 mm×120 mm×3 mm) covered by a transparent plate.The working fluid employed is ethanol.As a result,various flow patterns and their transitions are observed and found to be related to the fluid fill ratio,input heat load and the device orientation.Also the operational characteristics and working mechanism are discussed.展开更多
The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and therm...The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines.展开更多
The free-piston engine generator(FPEG)is regarded as the next generation of energy conversion system which may replace traditional engines in the future.The effect of key operational parameters like excess air ratio o...The free-piston engine generator(FPEG)is regarded as the next generation of energy conversion system which may replace traditional engines in the future.The effect of key operational parameters like excess air ratio of input mixture and ignition position on the engine performance of a dual-cylinder FPEG was investigated,and their sensitivity was analyzed in this paper.The operating compression ratio of the system is susceptible to changes in excess air ratio and ignition position.At the same time,it decreases from 15.8 to 6.6 when excess air ratio increases from 0.85 to 1.15,but it increases from 6.1 to 13.3 as ignition position increases from 15 mm to 20 mm.The operating frequency and indicated power are more sensitive to changes in excess air ratio than ignition position.But it is the opposite for the indicated thermal efficiency and friction loss.Excess air ratio and ignition position have a quite similar influence on heat transfer.Therefore,from the perspective of system operation and performance,it is preferable to keep excess air coefficient slightly below 1.0.In contrast,when selecting ignition position,it is of great importance to comprehensively consider the risk of structural damage caused by the increase in the compression ratio and in-cylinder gas pressure.展开更多
Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indice...Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease.展开更多
Background： To combine dinicopathological characteristics associated with lymph node metastasis for submucosal gastric cancer into a nomogram. Methods： We retrospectively analyzed 262 patients with submucosal gastri...Background： To combine dinicopathological characteristics associated with lymph node metastasis for submucosal gastric cancer into a nomogram. Methods： We retrospectively analyzed 262 patients with submucosal gastric cancer who underwent D2 gastrectomy between 1996 and 2012. The relationship between lymph node metastasis and clinicopathological features was statistically analyzed. With multivariate logistic regression analysis, we made a nomogram to predict the possibility of lymph node metastasis. Receiver operating characteristic （ROC） analysis was also performed to assess the predictive value of the model. Discrimination and calibration were performed using internal validation. Results： A total number of 48 （18.3%） patients with submucosal gastric cancer have pathologically lymph node metastasis. For submucosal gastric carcinoma, lymph node metastasis was associated with age, tumor location, macroscopic type, size, differentiation, histology, the existence of ulcer and lymphovascular invasion in univariate analysis （all P〈0.05）. The multivariate logistic old, macroscopic type III or mixed, undifferentiated type, regression analysis identified that age _〈50 years and presence of lymphovascular invasion were independent risk factors of lymph node metastasis in submucosal gastric cancer （all P〈0.05）. We constructed a predicting nomogram with all these factors for lymph node metastasis in submucosal gastric cancer with good discrimination [area under the curve （AUC） =0.844]. Internal validation demonstrated a good discrimination power that the actual probability corresponds closely with the predicted probability. Conclusions： We developed a nomogram to predict the rate of lymph node metastasis for submucosal gastric cancer. With good discrimination and internal validation, the nomogram improved individualized predictions for assisting clinicians to make appropriated treatment decision for submucosal gastric cancer patients.展开更多
The Low Frequency Synchromotor Drive Mine Hoist System fed by the cycloinverter has good features from the technological and economical point of view. According to the erating char acteristic of the mine hoist system,...The Low Frequency Synchromotor Drive Mine Hoist System fed by the cycloinverter has good features from the technological and economical point of view. According to the erating char acteristic of the mine hoist system, an advanced analysis is given to the construction, the operating characteristics and the harmonics of the magnetomotive force of the synchromotor fed by the cy cloinverter, and the beneficial suggestions are also given in this paper.展开更多
BACKGROUND ： Experimental animal models of intracerebral hemorrhag （ICH） are greatly needed, so the process of establishment should be ideal in hematoma formation and easy to operate. OBJECTIVE ： To construct mode...BACKGROUND ： Experimental animal models of intracerebral hemorrhag （ICH） are greatly needed, so the process of establishment should be ideal in hematoma formation and easy to operate. OBJECTIVE ： To construct model of ICH in rats with double injection of autologous blood taken from the cut tail cut and double withdrawal of the needle （shortened as two-step injection model）, and compare with those induced by single and double injections. DESIGN ： A randomized controlled tria SETTING： Department of Neurology, General Hospital of Military Area Command of Chinese PLA. MATERIALS： Thirty male Wistar rats of 10 to 12 months, weighing （400±25） g, provided by the Experimental Center of Medical Animals, General Hospital of Shenyang Military Area Command of Chinese PLA, were divided randomly into 3 groups with 10 rats in each group： two-step injection group, single injection group, double injection group. METHODS ： The experiment was carried out in the Department of Neurology, General Hospital of Military Area Command of Chinese PLA from March to June in 2004. Autologous blood ICH model in rats were established as follows： In the two-step injection group, 50 μL unclotted autologous blood was taken from the rat tail cut, then injected with microsyringe into the caudate nucleus, 10 μL injected at first, paused for 2 minutes, and then the rest 40 μL injected slowly and continuously within 2 minutes. After the injection, the needle was kept immovable for about 4 minutes, withdrawn 2.0 mm, again kept immovable for about 4 minute, and then removed wholly at a slow speed. In the single injection group, 50 μL unclotted tail blood was injected slowly and continuously all within 2 minutes and the needle was slowly removed;（4） In the double injection group, 10 mL blood was injected at first, paused for 2 minutes, the rest 40 μL injected evenly within 2 minutes, and then the needle was withdrawn slowly and uninterruptedly. Neurologic findings were scored in accordance with Longa＇s five-point scale （0-4 scores, the higher the score, the severer the neurological dysfunction）. The rats were killed to remove and sections were prepared, the morphological features of hematomas were grossly observed, the maximal diameter and size of hematomas in each slice were measured with the imaging analytical system, and the volume was calculated. Meanwhile, the conveniences of the techniques were compared. MAIN OUTCOME MEASURES： The morphological features and volume of hematomas, neurologic deficit score （NDS）, and the convenience of the techniques were compared. RESULTS： All the 30 rats were involved in the analysis of results without deletion. （1） Results of the morphological observation of volume of hematoma： In the two-step injection group, hematomas located in the right caudate nucleus area regularly in circular or analogously circular shape in each slice. The formation rate of hematomas in the single injection group and double injection group were lower than those in the two-step injection group [60% （6/10）, 80% （8/10）, 100% （10/10）, P〈 0.01, 0.05]. The volume of hematomas in the single injection group and double injection group were smaller than those in the two-step injection group [（28.5±14.8）, （33.4±7.4）, （41.6±3.9） mm3, P〈 0.01, 0.05]. （2） NDS results： The NDS scores in the single injection group and double injection group were smaller than that in the two-step injection group （0.90±0.83, 1.30±0.78, 1.90±0.57, P〈 0.05）. （3）Comparison of the convenience of the techniques： The double injection method allowed generating reproducible hematomas in rats with shortcomings that it needed autologous arterial blood from femoral artery, and precision instruments such as microinfusion pump. The two-step injection injected fresh unclotting blood taken directly from the tail cut with microsyringe into the rat brain, and it has the advantages of easy operation, no influence on the activity of thrombase, shorter duration for model establishment, and higher rate of hematoma formation, which could generate ideal and economical models of ICH. The two-step injection induced hemotoma regularly in circular or analogously circular shape in each slice, but those induced by single and double injections were mostly in strip or fusiform shapes and extending along the needle tracks or into the ventricle or subarachnoid space. CONCLUSION ： The autologous blood ICH model induced by the two-step injection method is a reproducible and reliable one in regular shape, which is better than those induced by double and single injections.展开更多
We present a conceptual configuration of a high-temperature superconducting（HTS）magnet made from REBCO（Re=Rare Earth,B=Barium,C=Copper,O=Oxide）annular plates,called a Bitter-like HTS magnet,which can operate in pe...We present a conceptual configuration of a high-temperature superconducting（HTS）magnet made from REBCO（Re=Rare Earth,B=Barium,C=Copper,O=Oxide）annular plates,called a Bitter-like HTS magnet,which can operate in persistent current mode without joint resistance and can be excited by a flux pump and without current leads and a persistent power supply.An REBCO annular magnet which can generate 1.5 T corresponding to the operating current density 80%of critical current density of the magnet at an operating temperature of65 K is conceptually designed.Then the thermal stability of the magnet is numerically simulated by Comsol software.Whein a piece of RBCO annular plate quenches,the maximum released energy is its stored energy because each REBCO annular plate in the Bitter-like magnet is in parallel.To calculate the stored energy in the REBCO annular plate,the inductance of every annular plate,including self-inductance and mutual inductance,is calculated.Compared with the minimum quench energy（MQE）and stored energy in one REBCO annular plate,the stored energy in one REBCO annular plate is always smaller than the MQE,and the REBCO annular plate will not be damaged even though the stored energy in the REBCO annular plate is fully released,which indicates that this 1.5 T Bitter-like magnet has the property of self-protection.展开更多
BACKGROUND Emerging evidence suggests that serum levels of pepsinogen(PG),gastrin-17(G17),carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA19-9),and CA72-4 may aid in distinguishing gastric cancer(GC)from gas...BACKGROUND Emerging evidence suggests that serum levels of pepsinogen(PG),gastrin-17(G17),carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA19-9),and CA72-4 may aid in distinguishing gastric cancer(GC)from gastric ulcer(GU).AIM To assess serum PG,G17,CEA,CA19-9,and CA72-4 in diagnosing GU and optimizing GC detection.METHODS A retrospective analysis was conducted from 263 patients treated at the Third People’s Hospital of Hefei,who were classified into three groups:Chronic non-atrophic gastritis(CG),GU,and GC.Fasting serum levels of PG,G17,CEA,CA19-9,and CA72-4 were measured and compared across the groups.RESULTS Serum levels of PGII and G17 were significantly elevated in both the GU and GC groups compared to the CG group(P<0.01),whereas the PGI/PGII ratio was markedly decreased(P<0.01).Levels of CEA,CA19-9,and CA72-4 were significantly higher in the GC group than in the CG and GU groups(P<0.01).Receiver operating characteristic curve analysis identified the optimal diagnostic cut-off values for GU and GC as follows:PGI(169.855 pmol/L),PGII(30.555μg/L),PGI/PGII ratio(16.529),G17(6.435 pmol/L),CEA(2.005 ng/mL),CA19-9(16.65 U/mL),and CA72-4(2.075 U/mL).The area under the curve for combined detection was 0.826(P<0.001),indicating good diagnostic performance.CONCLUSION Serological biomarkers effectively distinguish GC from GU,with combined detection of PGII,PGI/PGII ratio,G17,and tumor markers enhancing diagnostic accuracy.展开更多
Objectives:SocialNetworkAddiction(SNA)is becoming increasingly prevalent among college students;however,there remains a lack of consensus regarding the measurement tools and their optimal cutoff score.This study aims ...Objectives:SocialNetworkAddiction(SNA)is becoming increasingly prevalent among college students;however,there remains a lack of consensus regarding the measurement tools and their optimal cutoff score.This study aims to validate the 21-item SocialNetwork Addiction Scale-Chinese(SNAS-C)in its Chinese version and to determine its optimal cutoff score for identifying potential SNA cases within the college student population.Methods:A crosssectional survey was conducted,recruiting 3387 college students.Latent profile analysis(LPA)and receiver operating characteristic(ROC)curve analysis were employed to establish the optimal cutoff score for the validated 21-item SNAS-C.Results:Three profile models were selected based on multiple statistical criteria,classifying participants into low-risk,moderate-risk,and high-risk groups.The highest-risk group was defined as“positive”for SNA,while the remaining groups were considered“negative”,serving as the reference standard for ROC analysis.The optimal cutoff score was determined to be 72(sensitivity:98.2%,specificity:96.86%),with an overall classification accuracy of 97.0%.The“positive”group reported significantly higher frequency of social network usage,greater digitalmedia dependence scores,and a higher incidence of network addiction.Conclusion:This study identified the optimal cutoff score for the SNAS-C as≥72,demonstrating high sensitivity,specificity,and diagnostic accuracy.This threshold effectively distinguishes between high-risk and low-risk SNA.展开更多
A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment ...A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP.展开更多
BACKGROUND Contrast-enhanced ultrasonography(CEUS)is utilized to assess the therapeutic efficacy of interventional therapy in liver cancer patients,offering insights into tumor blood flow changes,angiogenesis,and tumo...BACKGROUND Contrast-enhanced ultrasonography(CEUS)is utilized to assess the therapeutic efficacy of interventional therapy in liver cancer patients,offering insights into tumor blood flow changes,angiogenesis,and tumor markers.AIM To evaluate the use of CEUS in examining the effectiveness of interventional therapy for liver cancer,we aim to investigate its diagnostic utility for tumor perfusion patterns,microvessel density,perfusion recovery,blood flow enhancement response,and alterations in tumor markers among patients receiving interventional therapy for liver cancer.METHODS The study involved 124 patients who underwent interventional therapy for liver cancer at Guangzhou First People’s Hospital from January 2022 to February 2024.All patients were examined using CEUS before treatment and at 1 month,3 months,and 6 months,and the concentrations of tumor markers were collected and statistically analyzed using Statistical Package for the Social Sciences 25.0.Receiver operating characteristic(ROC)curves were used to evaluate the diagnostic efficacy of CEUS and analyze its sensitivity,specificity,and correlation with clinical indicators.RESULTS Before treatment,tumor blood flow was primarily enhanced.After treatment,enhanced perfusion declined,while uniform and non-uniform perfusion increased,indicating reduced tumor activity.Enhanced perfusion decreased from 68.25%before treatment to 53.75%at 6 months post-treatment(F=6.123,P=0.016),indicating reduced tumor activity.The microvessel density of the tumors decreased significantly after treatment(P<0.05),and the proportion of low microvessel density increased.After treatment,perfusion recovery in the tumor area improved,the proportion of complete and partial responses gradually increased,and the proportion of stable lesions decreased(P<0.05).The levels of alphafetoprotein,carcinoembryonic antigen,and carbohydrate antigen 19-9 decreased by 68.7%,30.4%,and 41.6%,respectively,at 6 months post-treatment(P<0.05).CEUS showed a sensitivity of 85.72%,specificity of 92.31%,and area under the curve of 0.911(95%CI:0.883–0.939)for evaluating treatment response.ROC curve analysis showed that CEUS had high sensitivity and specificity and could effectively evaluate the efficacy of interventional therapy for liver cancer.CONCLUSION CEUS has high diagnostic value in evaluating therapeutic effects in patients with liver cancer following interventional therapy.It can reflect changes in tumor blood flow,angiogenesis,and tumor marker levels,providing an effective basis for real-time monitoring of treatment outcomes.展开更多
BACKGROUND With the increasing global incidence of mental illness,depression has become a serious problem among college students.AIM To investigate the relationship between depression and its correlates in Chinese ado...BACKGROUND With the increasing global incidence of mental illness,depression has become a serious problem among college students.AIM To investigate the relationship between depression and its correlates in Chinese adolescents and to identify diagnostic predictors of depression,examine the effects of binge eating,physical activity,and body dissatisfaction on depression among college students and to determine a diagnostic cutoff value for depression based on body dissatisfaction.METHODS We conducted a cross-sectional survey of 1286 college students in South China.Physical activity level,depressive symptoms,and binge eating behavior were assessed using the Physical Activity Scale-3,Zung Self-Rating Depression Scale,and Dutch Eating Behavior Questionnaire,respectively.The absolute difference between actual body mass index(BMI)and ideal BMI was used to indicate the level of body dissatisfaction.Structural equation modeling(SEM)and receiver operating characteristic(ROC)curve analysis were used to examine the relationships between these variables and depression.RESULTS The findings showed that female college students reported higher levels of depression.Physical activity,body dissatisfaction,and binge eating behavior were significantly associated with depression.SEM revealed that body dissatisfaction played a mediating role.A body dissatisfaction score of 1.73 was identified as the diagnostic cutoff value for predicting depression,with an area under the ROC curve of 70.0%,providing a basis for targeted interventions.CONCLUSION This study demonstrated a significant positive correlation between body dissatisfaction and depression.Low levels of physical activity and binge eating behaviors were found to heighten the risk of depression.Therefore,promoting physical activity and healthy eating habits among adolescents is essential.Additionally,the identification of a diagnostic threshold for body dissatisfaction represents a novel finding with important implications for early screening.Future longitudinal studies are recommended to further refine this diagnostic criterion.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is the most common pathological type of liver cancer and was the third leading cause of cancer-related deaths worldwide in 2020.AIM To evaluate the diagnostic potential of key t...BACKGROUND Hepatocellular carcinoma(HCC)is the most common pathological type of liver cancer and was the third leading cause of cancer-related deaths worldwide in 2020.AIM To evaluate the diagnostic potential of key tumor markers in serum,bile,and fecal samples for detecting HCC.METHODS Blood,bile,and fecal samples were collected from patients(n=265)with HCC and cholecystitis from Guangxi Medical University’s First Affiliated Hospital.Immunohistochemistry was performed on 69 HCC samples,and 16S ribosomal RNA sequencing was conducted on 166 fecal samples.Tumor marker cut-off values in bile and feces were determined using the Youden index,while serum biomarkers followed hospital standards.Diagnostic performance was evaluated using receiver operating characteristic analysis.RESULTS The areas under the curve(AUCs)for distinguishing HCC were 0.898,0.904,and 0.859 for serum alpha-fetoprotein(AFP),prothrombin induced by vitamin K absence-II(PIVKA-II),and bile AFP,respectively.Serum AFP had the highest diagnostic value(80%)for early-stage HCC.Combination analysis found that bile AFP and serum PIVKAII achieved the highest AUC of 0.965(P<0.001),suggesting that bile AFP may serve as a valuable complementary biomarker,particularly in cases where serum AFP is not significantly elevated.Additionally,bile AFP was positively correlated with Actinomyces,which plays a significant role in promoting tumorigenesis;and was negatively correlated with Faecalibacterium,which was associated with robust anticancer immune responses(P<0.05).These findings suggest the potential role of gut microbiota in modulating AFP levels and HCC progression.CONCLUSION Bile AFP improved the sensitivity of HCC detection,with the combination of bile AFP and PIVKA-II demonstrating the highest AUC for HCC diagnosis.AFP is associated with poorer clinical outcomes.展开更多
Background Electrocardiogram(ECG)analysis has emerged as a promising tool for detecting physiological changes linked to non-cardiac disorders.Given the close connection between cardiovascular and neurocognitive health...Background Electrocardiogram(ECG)analysis has emerged as a promising tool for detecting physiological changes linked to non-cardiac disorders.Given the close connection between cardiovascular and neurocognitive health,ECG abnormalities may be present in individuals with co-occurring neurocognitive conditions.This highlights the potential of ECG as a biomarker to improve detection,therapy monitoring and risk stratification in patients with neurocognitive disorders,an area that remains underexplored.Aims We aimed to demonstrate the feasibility of predicting neurocognitive disorders from ECG features across diverse patient populations.Methods ECG features and demographic data were used to predict neurocognitive disorders,as defined by the International Classification of Diseases 10th revision,focusing on dementia,delirium and Parkinson's disease.Internal and external validations were performed using the Medical Information Mart for Intensive CareⅣand ECG-View datasets.Predictive performance was assessed by the area under the receiver operating characteristic curve(AUROC)scores,and Shapley values were used to interpret feature contributions.Results Significant predictive performance was observed for several neurocognitive disorders.The highest predictive performance was observed for F03:dementia,with an internal AUROC of 0.848(95%confidence interval(CI)0.848 to 0.848)and an external AUROC of 0.865(95%CI 0.864 to 0.965),followed by G30:Alzheimer's disease,with an internal AUROC of 0.809(95%CI 0.808 to 0.810)and an external AUROC of 0.863(95%CI 0.863 to 0.864).Feature importance analysis revealed both established and novel ECG correlates.Conclusions These findings suggest that ECG holds promise as a non-invasive,explainable biomarker for selected neurocognitive disorders.This study demonstrates robust performance across cohorts and lays the groundwork for future clinical applications,including early detection and personalised monitoring.展开更多
BACKGROUND Syngeneic orthotopic tumor models offer an optimal functional tumor–immune interface for hepatocellular carcinoma research.Yet,unpredictable growth kinetics and spontaneous regression pose major obstacles....BACKGROUND Syngeneic orthotopic tumor models offer an optimal functional tumor–immune interface for hepatocellular carcinoma research.Yet,unpredictable growth kinetics and spontaneous regression pose major obstacles.Efficient induction protocols and continuous monitoring are therefore essential.Routine exploratory surgeries are ethically untenable,making non-invasive imaging modalities attractive alternatives.High-resolution magnetic resonance imaging and microcomputed tomography deliver detailed insights but incur substantial equipment costs,radiation risks,time demands,and require specialized expertise—challenges that limit their routine use.In contrast,ultrasound(US)imaging emerges as a cost-effective,radiation-free,and rapid approach,facilitating practical and ethical longitudinal assessment of tumor progression in preclinical studies.AIM To optimize the orthotopic hepatocellular carcinoma model and evaluate the potential of US imaging for accurate and cost-effective tumor monitoring.METHODS Hepatocellular carcinoma was induced in 28 Sprague Dawley rats by implanting 5×10^(6) N1S1 cells into the left lateral hepatic lobe.Tumor progression was monitored weekly via US.Upon reaching 100-150 mm^(3),an experimental group(n=14)received Sorafenib(40 mg/kg)orally on alternate days for 28 days;efficacy was compared to untreated controls.US accuracy was validated against micro-computed tomography,gross caliper measurements and histopathological analysis.Reliability and operator proficiency in US assessment were also evaluated.RESULTS US images procured 7-day post-surgery revealed a well-defined hypoechoic nodule at the left liver lobe tip,confirming successful tumor induction(mean volume 130±39 mm^(3)).Only three animals exhibited spontaneous regression by week 2,underscoring the model’s stability.Sorafenib treatment elicited a marked tumor reduction(678±103 mm^(3))vs untreated control(6005±1760 mm^(3)).US assessment demonstrated robust intra and interobserver reproducibility with high sensitivity and specificity for tumor detection.Moreover,US derived volumes correlated strongly with gross caliper measurements,histopathological analysis,and microcomputed tomography imaging,validating its reliability as a non-invasive monitoring tool in preclinical hepatocellular carcinoma studies.CONCLUSION The results demonstrate that US imaging is a reliable,cost-effective,and animal sparing approach with an easy tomaster protocol,enabling monitoring of tumor progression and therapeutic response in orthotopic liver tumor models.展开更多
基金The National Key Technology R&D Program of Chinaduring the 11th Five-Year Plan Period(No.2008BAJ12B04)China Postdoctoral Science Foundation(No.20090461050)+1 种基金the Project of Researchand Development of Ministry of Housing and Urban-Rural Development ofChina(No.2008-K1-26)the New Century Talent Project of Yangzhou University for Excellent Young Backbone Teacher(2008)
文摘In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model with freezing/melting phase changes is developed for the heat transfer analysis of the soil.Based on the numerical solution of the model,the variation trends of underground soil temperature of the SGSHPS operated in various alternate operation modes are discussed.The results indicate that,for the day-night and short-time interval alternate operation modes without solar energy,the operation time fraction of a solar heat source should be confined to from 50% to 58% when operated in an alternate period of 24 h.Meanwhile,the disadvantages of a natural resumption of soil temperature can be overcome effectively by solar energy filling,and an optimal operation effect can be achieved by integrating the mode of solar energy filling with other alternate modes.In addition,the accuracy of the presented model is verified by the experimental data of borehole wall temperatures.The conclusions can provide a reference for the optimization operation of the SGSHPS.
基金Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02303007the National Key Research and Development Program of China under Grant No 2016YFA0301701the Youth Innovation Promotion Association of the Chinese Academy of Sciences under Grant No 2016112
文摘A novel high-κ~ A1203/HfO2/AI203 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibits excellent program-erasable characteristics. A large memory window of ~4 V, a small leakage current density of ~2 ×10-6 Acre-2 at a gate voltage of 7V, a high charge trapping density of 1.42 × 1013 cm-2 at a working vo]tage of 4-10 V and good retention characteristics are observed. Furthermore, the programming （△ VFB = 2.8 V at 10 V for 10μs） and erasing speeds （△VFB =-1.7 V at -10 V for 10μs） of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-κ Al2O3/HfO2/Al2O3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.
基金Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02303007the National Key Research and Development Program of China under Grant No 2016YFA0301701the Youth Innovation Promotion Association of the Chinese Academy of Sciences under Grant No 2016112
文摘We propose and investigate a novel metal/SiO_2/Si_3N_4/SiO_2/SiGe charge trapping flash memory structure（named as MONOS）, utilizing Si Ge as the buried channel. The fabricated memory device demonstrates excellent programerasable characteristics attributed to the fact that more carriers are generated by the smaller bandgap of Si Ge during program/erase operations. A flat-band voltage shift 2.8 V can be obtained by programming at ＋11 V for 100 us. Meanwhile, the memory device exhibits a large memory window of ~7.17 V under ±12 V sweeping voltage, and a negligible charge loss of 18% after 104 s＇ retention. In addition, the leakage current density is lower than 2.52 × 10^（-7） A·cm^（-2） below a gate breakdown voltage of 12.5 V. Investigation of leakage current-voltage indicates that the Schottky emission is the predominant conduction mechanisms for leakage current. These desirable characteristics are ascribed to the higher trap density of the Si_3N_4 charge trapping layer and the better quality of the interface between the SiO_2 tunneling layer and the Si Ge buried channel. Therefore, the application of the Si Ge buried channel is very promising to construct 3 D charge trapping NAND flash devices with improved operation characteristics.
基金supported by the Major Project of Technology Transfer of Shandong Province (Grant No. 2009ZHZX1A1105)
文摘Loop heat pipes （LHPs） were designed for the alpha magnetic spectrometer （AMS-02） to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit （-20℃） in cold environment. Extensive experiments were performed on operation characteristics of LHPs with the bypass valve for AMS-02 during thermal vacuum and thermal balance （TVTB） test. We found that the bypass valve can start up successfully in cold environment. With the bypass valve, the evaporator temperature is stable and can meet the requirement of the cryocooler. We analyzed three operating modes of the bypass valve. Set point temperature and regulation temperature shifts were observed and their relations with the bypass valve temperature were given.
基金the Ger man National Science Foundation (GR-412/33-2)Shanghai Leading Academic Discipline Project (No.B604)
文摘This paper presents an experimental study including visualization on a flat plate closed loop pulsating heat pipes.It consists of a total of 40 channels with square cross section(2 mm×2 mm,165 mm long) machined directly on an aluminum plate(180 mm×120 mm×3 mm) covered by a transparent plate.The working fluid employed is ethanol.As a result,various flow patterns and their transitions are observed and found to be related to the fluid fill ratio,input heat load and the device orientation.Also the operational characteristics and working mechanism are discussed.
基金supported by Sichuan Science and Technology Program(No.24NSFSC4579)National Natural Science Foundation of China(No.12305193)+2 种基金Sichuan Science and Technology Program(No.23NSFSC6149)National Natural Science Foundation of China(No.12305194)Technology on Reactor System Design Technology Laboratory Stable support Funding(No.2023_JCJQ_LB_003).
文摘The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines.
基金Projects(51675043,52005038)supported by the National Natural Science Foundation of China。
文摘The free-piston engine generator(FPEG)is regarded as the next generation of energy conversion system which may replace traditional engines in the future.The effect of key operational parameters like excess air ratio of input mixture and ignition position on the engine performance of a dual-cylinder FPEG was investigated,and their sensitivity was analyzed in this paper.The operating compression ratio of the system is susceptible to changes in excess air ratio and ignition position.At the same time,it decreases from 15.8 to 6.6 when excess air ratio increases from 0.85 to 1.15,but it increases from 6.1 to 13.3 as ignition position increases from 15 mm to 20 mm.The operating frequency and indicated power are more sensitive to changes in excess air ratio than ignition position.But it is the opposite for the indicated thermal efficiency and friction loss.Excess air ratio and ignition position have a quite similar influence on heat transfer.Therefore,from the perspective of system operation and performance,it is preferable to keep excess air coefficient slightly below 1.0.In contrast,when selecting ignition position,it is of great importance to comprehensively consider the risk of structural damage caused by the increase in the compression ratio and in-cylinder gas pressure.
基金supported by the National Natural Science Foundation of China,No.82071909(to GF)the Natural Science Foundation of Liaoning Province,No.2023-MS-07(to HL)。
文摘Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease.
文摘Background： To combine dinicopathological characteristics associated with lymph node metastasis for submucosal gastric cancer into a nomogram. Methods： We retrospectively analyzed 262 patients with submucosal gastric cancer who underwent D2 gastrectomy between 1996 and 2012. The relationship between lymph node metastasis and clinicopathological features was statistically analyzed. With multivariate logistic regression analysis, we made a nomogram to predict the possibility of lymph node metastasis. Receiver operating characteristic （ROC） analysis was also performed to assess the predictive value of the model. Discrimination and calibration were performed using internal validation. Results： A total number of 48 （18.3%） patients with submucosal gastric cancer have pathologically lymph node metastasis. For submucosal gastric carcinoma, lymph node metastasis was associated with age, tumor location, macroscopic type, size, differentiation, histology, the existence of ulcer and lymphovascular invasion in univariate analysis （all P〈0.05）. The multivariate logistic old, macroscopic type III or mixed, undifferentiated type, regression analysis identified that age _〈50 years and presence of lymphovascular invasion were independent risk factors of lymph node metastasis in submucosal gastric cancer （all P〈0.05）. We constructed a predicting nomogram with all these factors for lymph node metastasis in submucosal gastric cancer with good discrimination [area under the curve （AUC） =0.844]. Internal validation demonstrated a good discrimination power that the actual probability corresponds closely with the predicted probability. Conclusions： We developed a nomogram to predict the rate of lymph node metastasis for submucosal gastric cancer. With good discrimination and internal validation, the nomogram improved individualized predictions for assisting clinicians to make appropriated treatment decision for submucosal gastric cancer patients.
文摘The Low Frequency Synchromotor Drive Mine Hoist System fed by the cycloinverter has good features from the technological and economical point of view. According to the erating char acteristic of the mine hoist system, an advanced analysis is given to the construction, the operating characteristics and the harmonics of the magnetomotive force of the synchromotor fed by the cy cloinverter, and the beneficial suggestions are also given in this paper.
文摘BACKGROUND ： Experimental animal models of intracerebral hemorrhag （ICH） are greatly needed, so the process of establishment should be ideal in hematoma formation and easy to operate. OBJECTIVE ： To construct model of ICH in rats with double injection of autologous blood taken from the cut tail cut and double withdrawal of the needle （shortened as two-step injection model）, and compare with those induced by single and double injections. DESIGN ： A randomized controlled tria SETTING： Department of Neurology, General Hospital of Military Area Command of Chinese PLA. MATERIALS： Thirty male Wistar rats of 10 to 12 months, weighing （400±25） g, provided by the Experimental Center of Medical Animals, General Hospital of Shenyang Military Area Command of Chinese PLA, were divided randomly into 3 groups with 10 rats in each group： two-step injection group, single injection group, double injection group. METHODS ： The experiment was carried out in the Department of Neurology, General Hospital of Military Area Command of Chinese PLA from March to June in 2004. Autologous blood ICH model in rats were established as follows： In the two-step injection group, 50 μL unclotted autologous blood was taken from the rat tail cut, then injected with microsyringe into the caudate nucleus, 10 μL injected at first, paused for 2 minutes, and then the rest 40 μL injected slowly and continuously within 2 minutes. After the injection, the needle was kept immovable for about 4 minutes, withdrawn 2.0 mm, again kept immovable for about 4 minute, and then removed wholly at a slow speed. In the single injection group, 50 μL unclotted tail blood was injected slowly and continuously all within 2 minutes and the needle was slowly removed;（4） In the double injection group, 10 mL blood was injected at first, paused for 2 minutes, the rest 40 μL injected evenly within 2 minutes, and then the needle was withdrawn slowly and uninterruptedly. Neurologic findings were scored in accordance with Longa＇s five-point scale （0-4 scores, the higher the score, the severer the neurological dysfunction）. The rats were killed to remove and sections were prepared, the morphological features of hematomas were grossly observed, the maximal diameter and size of hematomas in each slice were measured with the imaging analytical system, and the volume was calculated. Meanwhile, the conveniences of the techniques were compared. MAIN OUTCOME MEASURES： The morphological features and volume of hematomas, neurologic deficit score （NDS）, and the convenience of the techniques were compared. RESULTS： All the 30 rats were involved in the analysis of results without deletion. （1） Results of the morphological observation of volume of hematoma： In the two-step injection group, hematomas located in the right caudate nucleus area regularly in circular or analogously circular shape in each slice. The formation rate of hematomas in the single injection group and double injection group were lower than those in the two-step injection group [60% （6/10）, 80% （8/10）, 100% （10/10）, P〈 0.01, 0.05]. The volume of hematomas in the single injection group and double injection group were smaller than those in the two-step injection group [（28.5±14.8）, （33.4±7.4）, （41.6±3.9） mm3, P〈 0.01, 0.05]. （2） NDS results： The NDS scores in the single injection group and double injection group were smaller than that in the two-step injection group （0.90±0.83, 1.30±0.78, 1.90±0.57, P〈 0.05）. （3）Comparison of the convenience of the techniques： The double injection method allowed generating reproducible hematomas in rats with shortcomings that it needed autologous arterial blood from femoral artery, and precision instruments such as microinfusion pump. The two-step injection injected fresh unclotting blood taken directly from the tail cut with microsyringe into the rat brain, and it has the advantages of easy operation, no influence on the activity of thrombase, shorter duration for model establishment, and higher rate of hematoma formation, which could generate ideal and economical models of ICH. The two-step injection induced hemotoma regularly in circular or analogously circular shape in each slice, but those induced by single and double injections were mostly in strip or fusiform shapes and extending along the needle tracks or into the ventricle or subarachnoid space. CONCLUSION ： The autologous blood ICH model induced by the two-step injection method is a reproducible and reliable one in regular shape, which is better than those induced by double and single injections.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No 2018MS004
文摘We present a conceptual configuration of a high-temperature superconducting（HTS）magnet made from REBCO（Re=Rare Earth,B=Barium,C=Copper,O=Oxide）annular plates,called a Bitter-like HTS magnet,which can operate in persistent current mode without joint resistance and can be excited by a flux pump and without current leads and a persistent power supply.An REBCO annular magnet which can generate 1.5 T corresponding to the operating current density 80%of critical current density of the magnet at an operating temperature of65 K is conceptually designed.Then the thermal stability of the magnet is numerically simulated by Comsol software.Whein a piece of RBCO annular plate quenches,the maximum released energy is its stored energy because each REBCO annular plate in the Bitter-like magnet is in parallel.To calculate the stored energy in the REBCO annular plate,the inductance of every annular plate,including self-inductance and mutual inductance,is calculated.Compared with the minimum quench energy（MQE）and stored energy in one REBCO annular plate,the stored energy in one REBCO annular plate is always smaller than the MQE,and the REBCO annular plate will not be damaged even though the stored energy in the REBCO annular plate is fully released,which indicates that this 1.5 T Bitter-like magnet has the property of self-protection.
基金Supported by Chinese Medicine Research Project of Anhui Chinese Medicine Society,No.2024ZYYXH135.
文摘BACKGROUND Emerging evidence suggests that serum levels of pepsinogen(PG),gastrin-17(G17),carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA19-9),and CA72-4 may aid in distinguishing gastric cancer(GC)from gastric ulcer(GU).AIM To assess serum PG,G17,CEA,CA19-9,and CA72-4 in diagnosing GU and optimizing GC detection.METHODS A retrospective analysis was conducted from 263 patients treated at the Third People’s Hospital of Hefei,who were classified into three groups:Chronic non-atrophic gastritis(CG),GU,and GC.Fasting serum levels of PG,G17,CEA,CA19-9,and CA72-4 were measured and compared across the groups.RESULTS Serum levels of PGII and G17 were significantly elevated in both the GU and GC groups compared to the CG group(P<0.01),whereas the PGI/PGII ratio was markedly decreased(P<0.01).Levels of CEA,CA19-9,and CA72-4 were significantly higher in the GC group than in the CG and GU groups(P<0.01).Receiver operating characteristic curve analysis identified the optimal diagnostic cut-off values for GU and GC as follows:PGI(169.855 pmol/L),PGII(30.555μg/L),PGI/PGII ratio(16.529),G17(6.435 pmol/L),CEA(2.005 ng/mL),CA19-9(16.65 U/mL),and CA72-4(2.075 U/mL).The area under the curve for combined detection was 0.826(P<0.001),indicating good diagnostic performance.CONCLUSION Serological biomarkers effectively distinguish GC from GU,with combined detection of PGII,PGI/PGII ratio,G17,and tumor markers enhancing diagnostic accuracy.
基金supported by the National Natural Science Foundation of China(Grant No.72364006).
文摘Objectives:SocialNetworkAddiction(SNA)is becoming increasingly prevalent among college students;however,there remains a lack of consensus regarding the measurement tools and their optimal cutoff score.This study aims to validate the 21-item SocialNetwork Addiction Scale-Chinese(SNAS-C)in its Chinese version and to determine its optimal cutoff score for identifying potential SNA cases within the college student population.Methods:A crosssectional survey was conducted,recruiting 3387 college students.Latent profile analysis(LPA)and receiver operating characteristic(ROC)curve analysis were employed to establish the optimal cutoff score for the validated 21-item SNAS-C.Results:Three profile models were selected based on multiple statistical criteria,classifying participants into low-risk,moderate-risk,and high-risk groups.The highest-risk group was defined as“positive”for SNA,while the remaining groups were considered“negative”,serving as the reference standard for ROC analysis.The optimal cutoff score was determined to be 72(sensitivity:98.2%,specificity:96.86%),with an overall classification accuracy of 97.0%.The“positive”group reported significantly higher frequency of social network usage,greater digitalmedia dependence scores,and a higher incidence of network addiction.Conclusion:This study identified the optimal cutoff score for the SNAS-C as≥72,demonstrating high sensitivity,specificity,and diagnostic accuracy.This threshold effectively distinguishes between high-risk and low-risk SNA.
基金supported by the National Social Science Fund of China(Grand No.21XTJ001).
文摘A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP.
基金Supported by Science and Technology Program of Guangzhou,No.2024A03J1029Science and Technology Program of Chinese Medicine and Integrated Chinese and Western Medicine in Guangzhou,No.20252A010001.
文摘BACKGROUND Contrast-enhanced ultrasonography(CEUS)is utilized to assess the therapeutic efficacy of interventional therapy in liver cancer patients,offering insights into tumor blood flow changes,angiogenesis,and tumor markers.AIM To evaluate the use of CEUS in examining the effectiveness of interventional therapy for liver cancer,we aim to investigate its diagnostic utility for tumor perfusion patterns,microvessel density,perfusion recovery,blood flow enhancement response,and alterations in tumor markers among patients receiving interventional therapy for liver cancer.METHODS The study involved 124 patients who underwent interventional therapy for liver cancer at Guangzhou First People’s Hospital from January 2022 to February 2024.All patients were examined using CEUS before treatment and at 1 month,3 months,and 6 months,and the concentrations of tumor markers were collected and statistically analyzed using Statistical Package for the Social Sciences 25.0.Receiver operating characteristic(ROC)curves were used to evaluate the diagnostic efficacy of CEUS and analyze its sensitivity,specificity,and correlation with clinical indicators.RESULTS Before treatment,tumor blood flow was primarily enhanced.After treatment,enhanced perfusion declined,while uniform and non-uniform perfusion increased,indicating reduced tumor activity.Enhanced perfusion decreased from 68.25%before treatment to 53.75%at 6 months post-treatment(F=6.123,P=0.016),indicating reduced tumor activity.The microvessel density of the tumors decreased significantly after treatment(P<0.05),and the proportion of low microvessel density increased.After treatment,perfusion recovery in the tumor area improved,the proportion of complete and partial responses gradually increased,and the proportion of stable lesions decreased(P<0.05).The levels of alphafetoprotein,carcinoembryonic antigen,and carbohydrate antigen 19-9 decreased by 68.7%,30.4%,and 41.6%,respectively,at 6 months post-treatment(P<0.05).CEUS showed a sensitivity of 85.72%,specificity of 92.31%,and area under the curve of 0.911(95%CI:0.883–0.939)for evaluating treatment response.ROC curve analysis showed that CEUS had high sensitivity and specificity and could effectively evaluate the efficacy of interventional therapy for liver cancer.CONCLUSION CEUS has high diagnostic value in evaluating therapeutic effects in patients with liver cancer following interventional therapy.It can reflect changes in tumor blood flow,angiogenesis,and tumor marker levels,providing an effective basis for real-time monitoring of treatment outcomes.
基金Supported by Starting Research Fund from the Gannan Medical University,No.QD202121。
文摘BACKGROUND With the increasing global incidence of mental illness,depression has become a serious problem among college students.AIM To investigate the relationship between depression and its correlates in Chinese adolescents and to identify diagnostic predictors of depression,examine the effects of binge eating,physical activity,and body dissatisfaction on depression among college students and to determine a diagnostic cutoff value for depression based on body dissatisfaction.METHODS We conducted a cross-sectional survey of 1286 college students in South China.Physical activity level,depressive symptoms,and binge eating behavior were assessed using the Physical Activity Scale-3,Zung Self-Rating Depression Scale,and Dutch Eating Behavior Questionnaire,respectively.The absolute difference between actual body mass index(BMI)and ideal BMI was used to indicate the level of body dissatisfaction.Structural equation modeling(SEM)and receiver operating characteristic(ROC)curve analysis were used to examine the relationships between these variables and depression.RESULTS The findings showed that female college students reported higher levels of depression.Physical activity,body dissatisfaction,and binge eating behavior were significantly associated with depression.SEM revealed that body dissatisfaction played a mediating role.A body dissatisfaction score of 1.73 was identified as the diagnostic cutoff value for predicting depression,with an area under the ROC curve of 70.0%,providing a basis for targeted interventions.CONCLUSION This study demonstrated a significant positive correlation between body dissatisfaction and depression.Low levels of physical activity and binge eating behaviors were found to heighten the risk of depression.Therefore,promoting physical activity and healthy eating habits among adolescents is essential.Additionally,the identification of a diagnostic threshold for body dissatisfaction represents a novel finding with important implications for early screening.Future longitudinal studies are recommended to further refine this diagnostic criterion.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is the most common pathological type of liver cancer and was the third leading cause of cancer-related deaths worldwide in 2020.AIM To evaluate the diagnostic potential of key tumor markers in serum,bile,and fecal samples for detecting HCC.METHODS Blood,bile,and fecal samples were collected from patients(n=265)with HCC and cholecystitis from Guangxi Medical University’s First Affiliated Hospital.Immunohistochemistry was performed on 69 HCC samples,and 16S ribosomal RNA sequencing was conducted on 166 fecal samples.Tumor marker cut-off values in bile and feces were determined using the Youden index,while serum biomarkers followed hospital standards.Diagnostic performance was evaluated using receiver operating characteristic analysis.RESULTS The areas under the curve(AUCs)for distinguishing HCC were 0.898,0.904,and 0.859 for serum alpha-fetoprotein(AFP),prothrombin induced by vitamin K absence-II(PIVKA-II),and bile AFP,respectively.Serum AFP had the highest diagnostic value(80%)for early-stage HCC.Combination analysis found that bile AFP and serum PIVKAII achieved the highest AUC of 0.965(P<0.001),suggesting that bile AFP may serve as a valuable complementary biomarker,particularly in cases where serum AFP is not significantly elevated.Additionally,bile AFP was positively correlated with Actinomyces,which plays a significant role in promoting tumorigenesis;and was negatively correlated with Faecalibacterium,which was associated with robust anticancer immune responses(P<0.05).These findings suggest the potential role of gut microbiota in modulating AFP levels and HCC progression.CONCLUSION Bile AFP improved the sensitivity of HCC detection,with the combination of bile AFP and PIVKA-II demonstrating the highest AUC for HCC diagnosis.AFP is associated with poorer clinical outcomes.
文摘Background Electrocardiogram(ECG)analysis has emerged as a promising tool for detecting physiological changes linked to non-cardiac disorders.Given the close connection between cardiovascular and neurocognitive health,ECG abnormalities may be present in individuals with co-occurring neurocognitive conditions.This highlights the potential of ECG as a biomarker to improve detection,therapy monitoring and risk stratification in patients with neurocognitive disorders,an area that remains underexplored.Aims We aimed to demonstrate the feasibility of predicting neurocognitive disorders from ECG features across diverse patient populations.Methods ECG features and demographic data were used to predict neurocognitive disorders,as defined by the International Classification of Diseases 10th revision,focusing on dementia,delirium and Parkinson's disease.Internal and external validations were performed using the Medical Information Mart for Intensive CareⅣand ECG-View datasets.Predictive performance was assessed by the area under the receiver operating characteristic curve(AUROC)scores,and Shapley values were used to interpret feature contributions.Results Significant predictive performance was observed for several neurocognitive disorders.The highest predictive performance was observed for F03:dementia,with an internal AUROC of 0.848(95%confidence interval(CI)0.848 to 0.848)and an external AUROC of 0.865(95%CI 0.864 to 0.965),followed by G30:Alzheimer's disease,with an internal AUROC of 0.809(95%CI 0.808 to 0.810)and an external AUROC of 0.863(95%CI 0.863 to 0.864).Feature importance analysis revealed both established and novel ECG correlates.Conclusions These findings suggest that ECG holds promise as a non-invasive,explainable biomarker for selected neurocognitive disorders.This study demonstrates robust performance across cohorts and lays the groundwork for future clinical applications,including early detection and personalised monitoring.
基金Supported by Amrita Vishwa Vidyapeetham Seed Grant,No.K-PHAR-24-722DST INSPIRE Fellowship,No.IF190226.
文摘BACKGROUND Syngeneic orthotopic tumor models offer an optimal functional tumor–immune interface for hepatocellular carcinoma research.Yet,unpredictable growth kinetics and spontaneous regression pose major obstacles.Efficient induction protocols and continuous monitoring are therefore essential.Routine exploratory surgeries are ethically untenable,making non-invasive imaging modalities attractive alternatives.High-resolution magnetic resonance imaging and microcomputed tomography deliver detailed insights but incur substantial equipment costs,radiation risks,time demands,and require specialized expertise—challenges that limit their routine use.In contrast,ultrasound(US)imaging emerges as a cost-effective,radiation-free,and rapid approach,facilitating practical and ethical longitudinal assessment of tumor progression in preclinical studies.AIM To optimize the orthotopic hepatocellular carcinoma model and evaluate the potential of US imaging for accurate and cost-effective tumor monitoring.METHODS Hepatocellular carcinoma was induced in 28 Sprague Dawley rats by implanting 5×10^(6) N1S1 cells into the left lateral hepatic lobe.Tumor progression was monitored weekly via US.Upon reaching 100-150 mm^(3),an experimental group(n=14)received Sorafenib(40 mg/kg)orally on alternate days for 28 days;efficacy was compared to untreated controls.US accuracy was validated against micro-computed tomography,gross caliper measurements and histopathological analysis.Reliability and operator proficiency in US assessment were also evaluated.RESULTS US images procured 7-day post-surgery revealed a well-defined hypoechoic nodule at the left liver lobe tip,confirming successful tumor induction(mean volume 130±39 mm^(3)).Only three animals exhibited spontaneous regression by week 2,underscoring the model’s stability.Sorafenib treatment elicited a marked tumor reduction(678±103 mm^(3))vs untreated control(6005±1760 mm^(3)).US assessment demonstrated robust intra and interobserver reproducibility with high sensitivity and specificity for tumor detection.Moreover,US derived volumes correlated strongly with gross caliper measurements,histopathological analysis,and microcomputed tomography imaging,validating its reliability as a non-invasive monitoring tool in preclinical hepatocellular carcinoma studies.CONCLUSION The results demonstrate that US imaging is a reliable,cost-effective,and animal sparing approach with an easy tomaster protocol,enabling monitoring of tumor progression and therapeutic response in orthotopic liver tumor models.
