Objectives:To evaluate the safety and efficacy of implantation of subcutaneous implantable cardioverter defibrillator(S-ICD)after transvenous lead extraction(TLE)in ICD patients without pacing indications. Methods:All patients who underwent TLE at Peking University People's Hospital from June 2018 to October 2023 were consecutively included.TLE indication,S-ICD implantation indication,defibrillation threshold(DFT)test,complications and postoperative follow-up were collected and analyzed. Results:A total of 11 patients with TV-ICD underwent S-ICD implantation after TLE,eight patients were males and median age were 56(44,65)years.The indications for TLE were infection and lead dysfunction.Nine patients were implanted with S-ICD for secondary prevention,and the most common cause of implantation was ion channelopathies(5 cases).The operative time for S-ICD was 51(48,58)minutes and no perioperative complications were noted.Eight patients underwent DFT testing,and 100%were successful.During a median follow up of 30(9,39)months,a total of six appropriate treatments occurred in two patients,and no complications occurred,including inappropriate treatment,ineffective treatment,infection,lead malfunction and death. Conclusions:Our study provides evidence for S-ICD implantation as a replacement after TV-ICD removal.The S-ICD implantation after TLE is safe and effective.

Objective To propose a Q factor-based fatigue vibration evaluation method of the ultrasonic knife tip.Methods Firstly,an ultrasonic cutter fatigue testing table was established to realize repeated cutting,which was composed of a power supply module,a three-axis moving module,an ultrasonic cutter clamping module and a control module.Secondly,10 ultrasonic knives of some brand underwent fatigue testing with the table,during which non-contact measurement of the ultrasonic knife tip vibration was carried out and the Q factors were calculated at the five periods of the fatigue test,including the periods before cutting,after 500 times of cutting,after 1 000 times of cutting,after 2 000 times of cutting and after 3 000 times of cutting.Finally,the average cutting speed and burst pressure for coagulated vessels were computed at each period to validata the effectiveness of the method proposed.Results It's indicated that Q factor could effectively reflect the fatigue degradation of the ultrasonic knife tip,while the average cutting speed and burst pressure for coagulated vessels were difficult to efficiently evaluate the fatigue degradation level of the ultrasonic knife tip due to the uncertainty factors in the measurement process.Conclusion The proposed Q factor-based evaluation method can directly evaluate fatigue vibration of the ultrasonic knife tip in an accurate and quantitative manner.[Chinese Medical Equipment Journal,2024,45(6):17-22]

Objective To carry out accurate quantative evaluation of MRI scanning noise based on laser vibrometry technology.Methods Skull and spine MRI was performed with mute and conventional sequences.A laser vibrometry device was used to sample the surface vibration noise at the outer edge of the inspection hole of MRI system according to GB/T 16539-1996 Acoustics—Determination of sound power levels of noise sources using vibration velocity—Measurement for seal machinery,and the indicators of sound power level,sound pressure level and perceived noise level obtained by the three calculation methods(LPN1,LPN2 and LPN3)were analyzed with some dedicated MRI noise analysis software.Results The peak sound pressure levels for conventional and mute sequences of skull scanning were 81 and 63 dB(A),respectively,and mute sequence reduced the noise level significantly;the peak sound pressure levels for conventional and mute sequences of spine scanning were 79 and 75 dB(A),respectively,and the noise reduction level was significantly lower than that of skull scanning.Significant differences in noise reduction were not found in spine scanning sequences,while were found in skull scanning sequences.During spine and skull scanning LPN1,LPN2 and LPN3 obtained by the three calculation methods of conventional and mute sequences were all higher than the overall sound power and overall pressure levels obviously.Conclusion Mute sequence can not realize linear noise reduction for the whole frequency band,the perceived noise of the human ear during MRI scanning is related directly to the scanning sequence,and there may be some bias when only one physical indicator is involved in the noise evaluation of MRI system.[Chinese Medical Equipment Journal,2024,45(10):20-24]

Objective To prepare a core-shell electrostatically spun short fiber capable of sequential drug release and its suspen-sion for local injection use,and to observe the effects of the short fiber on human non-small cell lung cancer cell line A549 and its trans-planted tumor in nude mice.Methods The structure and drug release characteristics of different(SF-HD:shell hydroxycamptothecin,core adriamycin;SF-DH:shell adriamycin,core hydroxycamptothecin)staple fibers were observed.A549 cells were treated with each group of staple fibers,and real-time cellular analysis and flow technology were used to observe growth and apoptosis.Nude mice were in-oculated with A549 cells above the right hind limb,and after successful modeling,they were randomly divided into blank,control,SF-HD,and SF-DH groups,and injected with 200ul of saline,blank short fiber suspension,SF-DH suspension,and SF-HD suspension above the center of the tumor,respectively.The day of injection was 0 day,and the volume of the tumors and the weight of the mice were measured every two days and plotted as a curve.After 5,10 and 21 days of injection,tumor tissues were taken and observed by HE stai-ning.Results Compared with SF-DH,SF-HD had more obvious effects in inhibiting the growth and promoting the apoptosis of A549 cells and their transplanted tumors.Conclusion The SF-HD group had a better inhibitory effect on A549 cells and their transplanted tumors.The slow-release system of electrostatically spun short fibers prepared in this study can achieve the effect of slow controlled re-lease over time and is a promising drug delivery system for research.

Further evidence is needed to explore the impact of high-altitude environments on the neurologic function of neonates.Non-invasive techniques such as cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography can provide data on cerebral oxygenation and brain electrical activity.This study will conduct multiple cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography monitoring sessions at various time points within the first 3 days postpartum for healthy full-term neonates at different altitudes.The obtained data on cerebral oxygenation and brain electrical activity will be compared between different altitudes,and corresponding reference ranges will be established.The study involves 6 participating centers in the Chinese High Altitude Neonatal Medicine Alliance,with altitude gradients divided into 4 categories:800 m,1 900 m,2 400 m,and 3 500 m,with an anticipated sample size of 170 neonates per altitude gradient.This multicenter prospective cohort study aims to provide evidence supporting the impact of high-altitude environments on early brain function and metabolism in neonates.[Chinese Journal of Contemporary Pediatrics,2024,26(4):403-409]

With a global rise in morbidity rates， obesity has become a pressing public health issue. With increased adipocyte number and volume as the main characteristics， obesity is also manifested by metabolic disorders to varying degrees. At the same time， obesity is a risk factor for diabetes， hypertension， stroke， cancer， and cardiovascular diseases， imposing burdens on society and families. Influenced by lifestyle， environment， behavior， and genetics， obesity is caused by the interaction of many factors， and its pathological process is complex， involving inflammation， autophagy， and intestinal dysbiosis. The mitogen-activated protein kinase （MAPK） cascade reaction， a pivotal signaling pathway， plays a crucial role in cellular processes such as proliferation， differentiation， apoptosis， and stress responses. Both Chinese and international studies indicate that the MAPK signaling pathway can effectively regulate obesity through various pathways， including the modulation of adipocyte differentiation and apoptosis， appetite control， and inflammation improvement. Moreover， traditional Chinese medicine （TCM） has demonstrated significant efficacy in preventing and treating obesity， leveraging advantages such as multiple targets， diverse components， and minimal adverse effects. Research indicates that the MAPK signaling pathway is a primary focus of TCM regulation in this context， although a systematic review in this field is currently lacking. Therefore， this paper， by reviewing the latest Chinese and international research， provided a concise overview of the basic structure of the MAPK pathway， with a specific emphasis on recent progress in TCM interventions targeting the MAPK pathway for obesity treatment. The results indicate that regulating adipose tissue formation， differentiation， and thermogenesis， reducing inflammation and oxidative stress levels， and improving insulin sensitivity and metabolic disorders seem to be the main ways for TCM to regulate the MAPK pathway to prevent and treat obesity. However， it is necessary to find more research methods and explore potential mechanisms underlying TCM formulations based on the MAPK pathway for obesity prevention and treatment.

Objective To analyze the feasibility and efficacy of a deep convolutional neural network(DCNN)model based on chest CT images to evaluate bone mineral density(BMD).Methods A total of 1 048 health check subjects'2 096 central level images of lumbar 1 and 2 vertebral bodies were used for experiments and analysis in this retrospective study.According to the results of quanti-tative computed tomography(QCT)BMD measurement,the subjects were divided into three categories:normal,osteopenia,osteopo-rosis(OP).Herein,a DCNN segmentation model was constructed based on chest CT images[training set(n=1 096),tuning set(n=200),and test set(n=800)],the segmentation performance was evaluated using the Dice similarity coefficient(DSC)to com-pare the consistency with the manually sketched region of vertebral body.Then,the DCNN classification models 1(fusion feature construction of lumbar 1 and 2 vertebral bodies)and model 2(image feature construction of lumbar 1 alone)was developed based on the training set(n=530).Model performance was compared in a test set(n=418)by the receiver operating characteristic(ROC)curve analysis.Results When the number of images in the training set(n=300)was adopted,the DSC value was 0.950 in the test set.The results showed that the sensitivity,specificity and area under the curve(AUC)of model 1 and model 2 in diagno-sing osteopenia and OP were 0.716,0.960,0.952;0.941,0.948,0.980;0.638,0.954,0.940;0.843,0.959,0.978,respectively.The AUC value of normal model 1 was higher than that of model 2(0.990 vs 0.983,P=0.033),while there was no significant difference in AUC values between osteopenia and OP(P=0.210,0.546).Conclusion A DCNN may have the potential to evaluate bone mass based on chest CT images,which is expected to become an effective tool for OP screening.

Objective To investigate the attributable risk(AR)of Acinetobacter baumannii(AB)infection in criti-cally ill patients.Methods A multicenter retrospective cohort study was conducted among adult patients in inten-sive care unit(ICU).Patients with AB isolated from sterile body fluid and confirmed with AB infection in each cen-ter were selected as the infected group.According to the matching criteria that patients should be from the same pe-riod,in the same ICU,as well as with similar APACHE Ⅱ score(±5 points)and primary diagnosis,patients who did not infect with AB were selected as the non-infected group in a 1:2 ratio.The AR was calculated.Results The in-hospital mortality of patients with AB infection in sterile body fluid was 33.3％,and that of non-infected group was 23.1％,with no statistically significant difference between the two groups(P=0.069).The AR was 10.2％(95％CI:-2.3％-22.8％).There is no statistically significant difference in mortality between non-infected pa-tients and infected patients from whose blood,cerebrospinal fluid and other specimen sources AB were isolated(P＞0.05).After infected with AB,critically ill patients with the major diagnosis of pulmonary infection had the high-est AR.There was no statistically significant difference in mortality between patients in the infected and non-infec-ted groups(P＞0.05),or between other diagnostic classifications.Conclusion The prognosis of AB infection in critically ill patients is highly overestimated,but active healthcare-associated infection control for AB in the ICU should still be carried out.

Objective To analyze the atrioventricular synchronization rate after implantation of Micra AV leadless pacemaker,and the impact of postoperative programming optimization on atrioventricular synchronization rate.Methods A prospective cohort study was conducted to select patients with complete atrioventricular block who underwent Micra AV leadless pacemaker implantation at Beijing Anzhen Hospital from August 2022 to June 2023.Programming optimization were performed at 1 week,1 month,and 3 months postoperatively,and atrioventricular synchronization rate,electrical parameters,and echocardiography were recorded.Results A total of 68 patients with complete atrioventricular block implanted with Micra AV were selected,with an average age of(68.2±9.7)years,including 47 males(69.1％).All patients were successfully implanted with Micra AV,and there were no serious postoperative complications;The average threshold,sense,and impedance parameters were stable during 1 week,1 month,and 3 months after the procedure;There was no significant difference in the EF value of postoperative echocardiography(P=0.162);The average atrioventricular synchronization rates at 1 week,1 month,and 3 months postoperatively were(75.2％vs.83.8％vs.91.6％,P=0.001).Conclusions As an mechanical atrial sensing,Micra AV requires personalized adjustment of relevant parameters;Postoperative follow-up programming optimization plays an important role in the atrioventricular synchronization and comfort level in patients with complete atrioventricular block after implantation of Micra AV leadless pacemaker.

AIM To investigate the variation rules of main secondary metabolites in Hedysari Radix before and after rubbing strip.METHODS UPLC-MS/MS was adopted in the content determination of formononetin,ononin,calycosin,calycosin-7-glucoside,medicarpin,genistein,luteolin,liquiritigenin,isoliquiritigenin,vanillic acid,ferulic acid,γ-aminobutyric acid,adenosine and betaine,after which cluster analysis,principal component analysis and orthogonal partial least squares discriminant analysis were used for chemical pattern recognition to explore differential components.RESULTS After rubbing strip,formononetin,calycosin,liquiritigenin and γ-aminobutynic acid demonstrated increased contents,along with decreased contents of ononin,calycosin-7-glucoside and vanillic acid.The samples with and without rubbing strip were clustered into two types,calycosin-7-glucoside,formononetin,γ-aminobutynic acid,vanillic acid,calycosin-7-glucoside and formononetin were differential components.CONCLUSION This experiment clarifies the differences of chemical constituents in Hedysari Radix before and after rubbing strip,which can provide a reference for the research on rubbing strip mechanism of other medicinal materials.