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A spatiotemporal evolution model of a short-circuit arc to a secondary arc based on the improved charge simulation method
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作者 丛浩熹 王宇轩 +2 位作者 乔力盼 苏文晶 李庆民 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第1期62-73,共12页
The initial shape of the secondary arc considerably influences its subsequent shape.To establish the model for the arcing time of the secondary arc and modify the single-phase reclosing sequence,theoretical and experi... The initial shape of the secondary arc considerably influences its subsequent shape.To establish the model for the arcing time of the secondary arc and modify the single-phase reclosing sequence,theoretical and experimental analysis of the evolution process of the short-circuit arc to the secondary arc is critical.In this study,an improved charge simulation method was used to develop the internal-space electric-field model of the short-circuit arc.The intensity of the electric field was used as an independent variable to describe the initial shape of the secondary arc.A secondary arc evolution model was developed based on this model.Moreover,the accuracy of the model was evaluated by comparison with physical experimental results.When the secondary arc current increased,the arcing time and dispersion increased.There is an overall trend of increasing arc length with increasing arcing time.Nevertheless,there is a reduction in arc length during arc ignition due to short circuits between the arc columns.Furthermore,the arcing time decreased in the range of 0°-90°as the angle between the wind direction and the x-axis increased.This work investigated the method by which short-circuit arcs evolve into secondary arcs.The results can be used to develop the secondary arc evolution model and to provide both a technical and theoretical basis for secondary arc suppression. 展开更多
关键词 short-circuit arc secondary arc STOCHASTICITY improved charge simulation method arc time
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Challenging situation of coronary artery anomaly associated with ischemia and/or risk of sudden death
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作者 Shigenori Ito 《World Journal of Cardiology》 2024年第4期173-176,共4页
Coronary artery anomaly is known as one of the causes of angina pectoris and sudden death and is an important clinical entity that cannot be overlooked.The incidence of coronary artery anomalies is as low as 1%-2%of t... Coronary artery anomaly is known as one of the causes of angina pectoris and sudden death and is an important clinical entity that cannot be overlooked.The incidence of coronary artery anomalies is as low as 1%-2%of the general population,even when the various types are combined.Coronary anomalies are practically challenging when the left and right coronary ostium are not found around their normal positions during coronary angiography with a catheter.If there is atherosclerotic stenosis of the coronary artery with an anomaly and percutaneous coronary intervention(PCI)is required,the suitability of the guiding catheter at the entrance and the adequate back up force of the guiding catheter are issues.The level of PCI risk itself should also be considered on a caseby-case basis.In this case,emission computed tomography in the R-1 subtype single coronary artery proved that ischemia occurred in an area where the coronary artery was not visible to the naked eye.Meticulous follow-up would be crucial,because sudden death may occur in single coronary arteries.To prevent atherosclerosis with full efforts is also important,as the authors indicated admirably. 展开更多
关键词 Coronary artery anomaly Single coronary artery ISCHEMIA sudden death Percutaneous coronary intervention Coronary vessel anomalies Myocardial ischemia sudden cardiac death
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Analysis of gravity wave activity during stratospheric sudden warmings in the northern hemisphere
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作者 XuanYun Zeng Guang Zhong 《Earth and Planetary Physics》 EI CAS CSCD 2024年第2期415-422,共8页
Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The ... Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important issue.Using temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW events.During the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°W.During these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward extension.The E_(p)usually increased,while partially filtered by the eastward zonal winds.When zonal winds weakened or turned westward,E_(p)began to strengthen.After SSWs,the E_(p)usually decreased.These observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work. 展开更多
关键词 stratospheric sudden warming gravity wave wind filter
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Protocol of Investigation on Sudden Death at Autopsy, Including Molecular, Genetic and Toxicology Testing
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作者 Gaetano Thiene Donata Favretto 《World Journal of Cardiovascular Surgery》 2024年第6期78-86,共9页
The role of the autopsy: 1) Whether the death is ascribable to a natural or unnatural cause and when natural, if cardiac or extra-cardiac;2) The nosology of the cardiac diseases and the mechanism of cardiac death, whe... The role of the autopsy: 1) Whether the death is ascribable to a natural or unnatural cause and when natural, if cardiac or extra-cardiac;2) The nosology of the cardiac diseases and the mechanism of cardiac death, whether arrhythmic or mechanical;3) If the cardiac disease is inherited, screening and counselling of the next of kin is required. About 30% of sudden deaths is ascribable to genetically determined morbid entities, mostly transmissible with the autosomal dominant pattern of inheritance, so that 50% of the first degree relatives are genetically affected (“carriers”) and exposed at risk;4) If toxic or illicit drug abuse was involved. 展开更多
关键词 Family Screening GENETICS INHERITANCE Molecular Autopsy sudden Death TOXICOLOGY
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Optimization of short-circuit transition parameters of Q235B steel GMAW based on orthogonal gray relational analysis
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作者 陈昌荣 唐宝林 +2 位作者 叶宇杰 练国富 黄旭 《China Welding》 CAS 2024年第2期39-49,共11页
In gas metal arc welding(GMAW)process,the short-circuit transition was the most typical transition observed in molten metal droplets.This paper used orthogonal tests to explore the coupling effect law of welding proce... In gas metal arc welding(GMAW)process,the short-circuit transition was the most typical transition observed in molten metal droplets.This paper used orthogonal tests to explore the coupling effect law of welding process parameters on the quality of weld forming under short-circuit transition,the design of 3 factors and 3 levels of a total of 9 groups of orthogonal tests,welding current,welding voltage,welding speed as input parameters:effective area ratio,humps,actual linear power density,aspect ratio,Vickers hardness as output paramet-ers(response targets).Using range analysis and trend charts,we can visually depict the relationship between input parameters and a single output parameter,ultimately determining the optimal process parameters that impact the single output index.Then combined with gray the-ory to transform the three response targets into a single gray relational grade(GRG)for analysis,the optimal combination of the weld mor-phology parameters as follows:welding current 100 A,welding voltage 25 V,welding speed 30 cm/min.Finally,validation experiments were conducted,and the results showed that the error between the gray relational grade and the predicted value was 2.74%.It was observed that the effective area ratio of the response target significantly improved,validating the reliability of the orthogonal gray relational method. 展开更多
关键词 short-circuit transition orthogonal test gray relational forming quality
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Modified intratympanic steroid therapy for sudden sensorineural hearing loss via tympanic tube and gelfoam as a salvage treatment
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作者 Sichao Liang Yunshuo Li +6 位作者 Zhenping Guo Manlin Lu Xin Li Jia Xu Wenjing Chen Juanjuan Gao Haijin Yi 《Journal of Otology》 CAS CSCD 2024年第1期19-23,共5页
Background: Sudden sensorineural hearing loss(SSNHL) is a prevalent emergency in ear, nose, and throat practice. Previous studies have demonstrated that intratympanic steroid therapy(IST) can serve as a salvage treatm... Background: Sudden sensorineural hearing loss(SSNHL) is a prevalent emergency in ear, nose, and throat practice. Previous studies have demonstrated that intratympanic steroid therapy(IST) can serve as a salvage treatment for SSNHL after the failure of systemic steroid therapy(SST).Objective: This study aimed to analyze the efficacy of modified IST involving the insertion of a tympanic tube and gelfoam as a salvage treatment for patients with SSNHL, and to explore its associated factors.Methods: Totally, 74 patients who were aged 22–81 years with SSNHL were enrolled and allocated to either the control group(n = 25) or the treatment group(n = 49) based on their treatment modalities. All patients received SST lasting for at least 7 days. Subsequently, patients in the treatment group, after SST failure, underwent IST twice a week for 2–6 weeks, while the control group did not. Efficacy was assessed by the improvement in pure tone average at the affected frequency at the beginning and end of IST.Results: Hearing improvement in all patients after IST in the treatment group was 9.71 ± 14.84 dB, with significant improvement at affected frequencies(250-8000 Hz) compared with the control group(P < 0.05). The findings indicated the duration from the onset of SSNHL to the beginning of IST as an independent factor for pure tone average improvement after treatment(P = 0.002), whereas age, duration of SST, and time of IST were not(P > 0.05).Conclusion: The modified IST was demonstrated to be a safe and effective method as a salvage treatment for SSNHL. This study explored the efficacy of a modified IST approach, incorporating the utilization of tympanic tubes and gelfoam as key components. The findings underscore the advantages of gelfoam as a strategic drug carrier placed in the round window niche. By minimizing drug loss, extending action time, and increasing perilymph concentration, gelfoam enhances the therapeutic impact of IST, contributing to improved hearing outcomes in patients with SSNHL. 展开更多
关键词 Modified intratympanic steroid therapy sudden sensorineural hearing loss GELFOAM Tympanic tube
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The sudden ocean warming and its potential influences on earlyfrozen landfast ice in the Prydz Bay, East Antarctica
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作者 Haihan Hu Jiechen Zhao +4 位作者 Jingkai Ma Igor Bashmachnikov Natalia Gnatiuk Bo Xu Fengming Hui 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第5期65-77,共13页
The ocean conditions beneath the ice cover play a key role in understanding the sea ice mass balance in the polar regions.An integrated high-frequency ice-ocean observation system,including Acoustic Doppler Velocimete... The ocean conditions beneath the ice cover play a key role in understanding the sea ice mass balance in the polar regions.An integrated high-frequency ice-ocean observation system,including Acoustic Doppler Velocimeter,Conductivity-Temperature-Depth Sensor,and Sea Ice Mass Balance Array(SIMBA),was deployed in the landfast ice region close to the Chinese Zhongshan Station in Antarctica.A sudden ocean warming of 0.14℃(p<0.01)was observed beneath early-frozen landfast ice,from(−1.60±0.03)℃during April 16-19 to(−1.46±0.07)℃during April 20-23,2021,which is the only significant warming event in the nearly 8-month records.The sudden ocean warming brought a double rise in oceanic heat flux,from(21.7±11.1)W/m^(2) during April 16-19 to(44.8±21.3)W/m^(2) during April 20-23,2021,which shifted the original growth phase at the ice bottom,leading to a 2 cm melting,as shown from SIMBA and borehole observations.Simultaneously,the slowdown of ice bottom freezing decreased salt rejection,and the daily trend of observed ocean salinity changed from+0.02 d^(-1) during April 16-19,2021 to+0.003 d^(-1) during April 20-23,2021.The potential reasons are increased air temperature due to the transit cyclones and the weakened vertical ocean mixing due to the tide phase transformation from semi-diurnal to diurnal.The high-frequency observations within the ice-ocean boundary layer enhance the comprehensive investigation of the ocean’s influence on ice evolution at a daily scale. 展开更多
关键词 sudden ocean warming oceanic heat flux landfast ice Zhongshan Station in-situ observation
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Therapeutic efficacy of methylprednisolone sodium succinate via diverse administration routes for mid-to high-frequency sudden sensorineural hearing loss
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作者 Xiang-Da Meng Ting-Ting Li Li-Min Deng 《World Journal of Clinical Cases》 SCIE 2024年第18期3321-3331,共11页
BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use o... BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use of methylprednisolone sodium succinate(MPSS)via different administration routes,in combination with conventional medications,remains a topic of interest.AIM To compare the therapeutic efficacy of MPSS administered via different routes in combination with conventional drugs for the treatment of mid-to high-frequency SSNHL.METHODS The medical records of 109 patients with mid-to high-frequency SSNHL were analyzed.The patients were divided into three groups based on the route of administration:Group A[intratympanic(IT)injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection],Group B(intravenous injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection),and Group C(single IT injection of MPSS).The intervention effects were compared and analyzed.RESULTS The posttreatment auditory thresholds in Group A(21.23±3.34)were significantly lower than those in Groups B(28.52±3.36)and C(30.23±4.21;P<0.05).Group A also exhibited a significantly greater speech recognition rate(92.23±5.34)than Groups B and C.The disappearance time of tinnitus,time to hearing recovery,and disappearance time of vertigo in Group A were significantly shorter than those in Groups B and C(P<0.05).The total effective rate in Group A(97.56%)was significantly greater than that in Groups B and C(77.14%and 78.79%,χ^(2)=7.898,P=0.019).Moreover,the incidence of adverse reactions in Groups A and C was significantly lower than that in Group B(4.88%,3.03%vs 2.57%,χ^(2)=11.443,P=0.003),and the recurrence rate in Group A was significantly lower than that in Groups B and C(2.44%vs 20.00%vs 21.21%,χ^(2)=7.120,P=0.028).CONCLUSION IT injection of MPSS combined with conventional treatment demonstrates superior efficacy and safety compared to systemic administration via intravenous infusion and a single IT injection of MPSS.This approach effectively improves patients'hearing and reduces the risk of disease recurrence. 展开更多
关键词 sudden loss of hearing at middle-and high-frequency of the descending type Methylprednisolone sodium succinate Intratympanic injection Intravenous injection
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Clinical characteristics and analysis of vestibular-evoked myogenic potentials in patients with sudden sensorineural hearing loss in different ages
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作者 Yan-Zhuo Zhang Ya-Bo Wang +6 位作者 Jing-Lei Fang Yue-Tang Wang Gui-Fang Li Ran-Ran Liu Shu-Jing Shi Chun-Hua Wang Yong-Tao Tian 《World Journal of Clinical Cases》 SCIE 2024年第19期3760-3766,共7页
BACKGROUND Numerous studies have found that patients experiencing sudden sensorineural hearing loss(SSHL),with or without accompanying vertigo,often show impaired vestibular function.However,there is a dearth of studi... BACKGROUND Numerous studies have found that patients experiencing sudden sensorineural hearing loss(SSHL),with or without accompanying vertigo,often show impaired vestibular function.However,there is a dearth of studies analyzing vestibularevoked myogenic potentials(VEMPs)in SSHL patients across various age groups.AIM To investigate vestibular condition in SSHL patients across various age demographics.METHODS Clinical data of 84 SSHL patients were investigated retrospectively.Audiometry,cervical vestibular evoked myogenic potentials(c-VEMPs),and ocular vestibular evoked myogenic potentials(o-VEMPs)were conducted on these patients.Parameters assessed included the latencies of P1 and N1 waves,as well as the amplitudes of P1–N1 waves.Moreover,the study evaluated the influence of factors such as sex,affected side,configuration of hearing loss,and presence of accompanying vertigo.RESULTS Among the 84 SSHL patients,no significant differences were observed among the three groups in terms of gender,affected side,and the presence or absence of vertigo.Group II(aged 41–60 years)had the highest number of SSHL cases.The rates of absent o-VEMPs in the affected ears were 20.83%,31.58%,and 22.72%for the three age groups,respectively,with no statistically significant difference among them.The rates of absent c-VEMPs in the affected ears were 8.3%,34.21%,and 18.18%for the three age groups,respectively,with significant differences.In the unaffected ears,there were differences observed in the extraction rates of o-VEMPs in the unaffected ears among the age groups.In the three age groups,no significant differences were noted in the three age groups in the latencies of P1 and N1 waves or in the amplitude of N1–P1 waves for c-VEMPs and o-VEMPs,either on the affected side or on the unaffected side,across the three age groups.CONCLUSION The extraction rate of VEMPs is more valuable than parameters.Regardless of the presence of vertigo,vestibular organs are involved in SSHL.Notably,SSHL patients aged 41–60 appear more susceptible to damage to the inferior vestibular nerve and saccule. 展开更多
关键词 sudden sensorineural hearing loss Cervical vestibular evoked myogenic potential Ocular vestibular evoked myogenic potential VERTIGO Pure tone audiometry
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Stability analysis of CO_(2)gas shielded welding short-circuit transition process based on GMAW dynamic model 被引量:1
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作者 赵一帆 王莹 +4 位作者 刘瑞涛 孟令坤 宋白钰 赵津 王重阳 《China Welding》 CAS 2023年第4期55-68,共14页
Base on the arc phase and short-circuit phase and their relationship, the paper considers the changes of the extension of wire, the arc length, liquid bridge resistance and mass of liquid bridge, combines the improved... Base on the arc phase and short-circuit phase and their relationship, the paper considers the changes of the extension of wire, the arc length, liquid bridge resistance and mass of liquid bridge, combines the improved “mass-spring” model with the loop model of welding power system, puts forward the critical judgment condition of droplet transition, and establishes a more accurate dynamic model for describing the short-circuit transition process. The dynamic changes of short-circuit transfer frequency, welding current and voltage, contact droplet and residual droplet equivalent radius and droplet equivalent radius at different wire feeding speeds were calculated and analyzed, and compared with the experimental results. It shows that the fluctuation of droplet displacement, velocity and wire extension length at the optimal arc starting point is the smallest. The smaller the initial liquid bridge curvature radius is, the better the stability of short-circuit transfer is. 展开更多
关键词 short-circuit transition dynamic model STABILITY equivalent radius of droplet statistical distribution
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Awareness of the Importance of Cardiopulmonary Resuscitation Skills Following the Sudden Cardiac Arrest of Damar Hamlin during a Buffalo Bills Game
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作者 Puja Sengupta Mariana Adieb +1 位作者 Simona Maksimyan Maxim Crasta 《Journal of Biosciences and Medicines》 2023年第6期161-170,共10页
Background: Cardiopulmonary resuscitation (CPR) is a life-saving skill that is often overlooked until a tragic event occurs. A popular NFL player, Damar Hamlin, safety for the Buffalo Bills, suffered a cardiac arrest ... Background: Cardiopulmonary resuscitation (CPR) is a life-saving skill that is often overlooked until a tragic event occurs. A popular NFL player, Damar Hamlin, safety for the Buffalo Bills, suffered a cardiac arrest on January 2, 2023. Due to prompt intervention and CPR, Hamlin survived the arrest and is playing again. This research sought to understand how people respond to this event on the internet. It also seeks to understand how this response can be used to raise CPR awareness. Design and Methods: Using Google Trends and Twitter data, we searched, downloaded, and retrospectively analyzed search interests relative to Hamlin’s cardiac arrest for a one-year duration. We searched for related keywords in the United States from March 2022 to March 2023, including “Damar Hamlin”, “sudden cardiac death”, “heart attack”, and “CPR”. Results: There was a significant rise in post-event Google searches that combined the terms “Damar Hamlin” and “SCD” (M = -28898.88, SE = 1537.66;t = 1.62, p Conclusion: Based on the analytics of these platforms, it can be concluded that there were active discussions and an awareness of life-saving skills such as CPR along with Hamlin’s cardiac event by his fans, as demonstrated by the data gathered from these platforms. This can provide us with valuable insight into human behavior and help us leverage this knowledge to promote health. 展开更多
关键词 sudden Cardiac Death CPR Heart Attack Damar Hamlin
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Initial steps on the analysis of the underlying pharmacological mechanisms of Wendan decoction on sudden deafness using network pharmacology and molecular docking
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作者 SHIMING YE YUFENG ZHANG +4 位作者 TING LIU CONG WANG ZHENG YAN WANDONG SHE HAIBING HUA 《BIOCELL》 SCIE 2023年第9期1947-1964,共18页
Background:Despite its widespread therapeutic use and effectiveness,the underlying pharmacologic mechanisms of Wendan decoction(WDD)and how it works to treat sudden deafness(SD)remain unclear.In this study,the pharmac... Background:Despite its widespread therapeutic use and effectiveness,the underlying pharmacologic mechanisms of Wendan decoction(WDD)and how it works to treat sudden deafness(SD)remain unclear.In this study,the pharmacological mechanisms of WDD underlying SD were analyzed using network pharmacology and molecular docking.Methods:The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP)was employed to identify the active compounds and target genes of WDD,and genes associated with SD were screened on five databases.RGUI conducted Gene Ontology(GO)functional and the Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses.A compound-target network was established using Cytoscape,and the STRING database created a protein-protein interaction(PPI)network to identify the key compounds and targets.Subsequently,a network of crucial compound-target was generated for further molecular docking analysis.For molecular docking simulations of the macromolecular target proteins and their matching ligand molecules,AutoDock Vina and AutoDockTool were utilized.Results:TCMSP identified 162 active target genes and 36 active compounds for WDD.The active target genes were compared with the 2271 genes associated with SD to identify 70 intersecting active target genes linked to 34 active compounds.The GO functional enrichment and KEGG pathway enrichment analyses were undertaken,and compound–target,and PPI networks were built.The key compounds and protein targets were identified and integrated to form a key compound–target network.Eventually,molecular docking was performed to investigate the interactions of the protein targets with their respective compounds.Conclusion:This study highlights the mechanisms of multi-compounds,targets,and pathways of WDD acting on SD and provides further evidence of crucial compounds and their matching target proteins of WDD acting on SD. 展开更多
关键词 Wendan decoction sudden deafness Network pharmacology Molecular docking
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Sudden death in the southern region of Saudi Arabia:A retrospective study
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作者 Ahmed Mohamed Ahmed Al-Emam Abdulrahman Dajam +3 位作者 Mohammed Alrajhi Waleed Alfaifi Mubarak Al-Shraim Ahmed Mohamed Helaly 《World Journal of Clinical Cases》 SCIE 2023年第20期4843-4851,共9页
BACKGROUND Sudden death is unanticipated,non-violent death taking place within the first 24 h after the onset of symptoms.It is a major public health problem worldwide.Moreover,the effects of living at moderate altitu... BACKGROUND Sudden death is unanticipated,non-violent death taking place within the first 24 h after the onset of symptoms.It is a major public health problem worldwide.Moreover,the effects of living at moderate altitude on mortality are poorly understood.AIM To retrospectively report the frequency and the main causes of sudden deaths in relation to total deaths at Asir Central Hospital,2255 m above sea level,in the southern region of Saudi Arabia over a period of 4 years from 2013 to 2016.METHODS The medical records of 1821 deaths were examined and showed 353 cases(19.4%)of sudden death.RESULTS The highest incidence of sudden death was among the elderly(51%),whereas,the lowest was among children and adolescents(6.5%).With regard to gender,the incidence of sudden death was higher in males(54.4%)compared to 45.6% in females.In this study,we found that the most common direct causes of sudden death were cardiovascular diseases(29.2%),respiratory disease(22.7%),infectious disease(12.2%),cancer(9.4%)and hematological diseases(6.2%).With respect to seasonal variation,the highest incidence was during winter(31.32%)followed by summer(25.8%).CONCLUSION The results of this study will help emergency physicians and health care providers to exercise due care to reduce the incidence of sudden death and raise public awareness about the impact of sudden death. 展开更多
关键词 sudden death High altitude CARDIOVASCULAR Gender distribution Age Seasonal variation
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Research on Inter-turn Short-circuit Fault Diagnosis Method Based on High Frequency Voltage Residual for PMSM
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作者 Xiaobao Feng Bo Wang +2 位作者 Chaohui Liu Jiayun Zeng Zheng Wang 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第3期256-265,共10页
Inter-turn fault is a serious stator winding short-circuit fault of permanent magnet synchronous machine(PMSM). Once it occurs, it produces a huge short-circuit current that poses a great risk to the safe operation of... Inter-turn fault is a serious stator winding short-circuit fault of permanent magnet synchronous machine(PMSM). Once it occurs, it produces a huge short-circuit current that poses a great risk to the safe operation of PMSM. Thus, an inter-turn short-circuit fault(ITSCF) diagnosis method based on high frequency(HF) voltage residual is proposed in this paper with proper HF signal injection. First, the analytical models of PMSM after the ITSCF are deduced. Based on the model, the voltage residual at low frequency(LF) and HF can be obtained. It is revealed that the HF voltage residual has a stronger ITSCF detection capability compared to the LF voltage residual. To obtain optimal fault signature, a 3-phase symmetrical HF voltage is injected into the machine drive system, and the HF voltage residuals are extracted. The fault indicator is defined as the standard deviation of the 3-phase HF voltage residuals. The effectiveness of the proposed ITSCF diagnosis method is verified by experiments on a triple 3-phase PMSM. It is worth noting that no extra hardware equipment is required to implement the proposed method. 展开更多
关键词 Inter-turn short-circuit fault(ITSCF) Permanent magnet synchronous machine(PMSM) High frequency(HF)injection Voltage residual Fault diagnosis
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阀后管道突扩对控制阀门流阻特性的影响 被引量:1
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作者 王蛟 胡亚安 +1 位作者 陈亮 王召兵 《流体机械》 CSCD 北大核心 2024年第1期41-47,共7页
为准确地描述非均匀流条件下控制阀门阀后采用突扩管道后的流阻特性,针对典型控制阀门(活塞式调流阀与固定式锥形阀),采用物理模型试验与理论分析方法,基于阀后突扩管道内的流场结构及试验段压力特性,研究阀后管道突扩对典型控流调压阀... 为准确地描述非均匀流条件下控制阀门阀后采用突扩管道后的流阻特性,针对典型控制阀门(活塞式调流阀与固定式锥形阀),采用物理模型试验与理论分析方法,基于阀后突扩管道内的流场结构及试验段压力特性,研究阀后管道突扩对典型控流调压阀门流阻特性的影响规律。结果表明,不同阀型采用相同突扩体时的流阻特性变化程度不同,阀型的影响主要体现在改变了突扩体的入流、出流条件。在规范公式的基础上,考虑阀门出流流场结构(突扩体入流条件)与水流缩脉(突扩体出流条件)的影响,分析得到管道突扩比与阀门流量系数的定量关系,规范计算值与试验值的最大差异约为8%,优化公式计算值与试验值最大差异约为1%,说明改进后的突扩体流阻系数公式的计算精度较规范公式有所提高。研究结果可为高压差、大流量调流调压系统管路设计提供参考。 展开更多
关键词 控制阀门 突扩体 流量系数 流场结构 水流缩脉
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巴曲酶联合金纳多注射液治疗突发性耳聋伴眩晕患者的临床疗效观察
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作者 闫娟 拓明祥 +4 位作者 王宏 田青 杨红丽 安丽 石昊 《中国药师》 CAS 2024年第3期470-476,共7页
目的 探讨巴曲酶(BX)联合金纳多注射液(GIS)对突发性耳聋伴眩晕(SDV)患者的临床疗效。方法 回顾性选取2020年4月至2023年1月延安市人民医院收治的SDV患者为研究对象,依据患者治疗方案不同分为BX组(地塞米松联合BX)和GIS组(地塞米松联合B... 目的 探讨巴曲酶(BX)联合金纳多注射液(GIS)对突发性耳聋伴眩晕(SDV)患者的临床疗效。方法 回顾性选取2020年4月至2023年1月延安市人民医院收治的SDV患者为研究对象,依据患者治疗方案不同分为BX组(地塞米松联合BX)和GIS组(地塞米松联合BX和GIS)。比较两组患者治疗后临床疗效、听力恢复时间、耳鸣缓解时间、眩晕缓解时间。观察并比较治疗期间不良反应发生情况。比较两组患者治疗前后血清炎症因子[肿瘤坏死因子-α(TNF-α)、超敏C反应蛋白(HsCRP)、白细胞介素-6(IL-6)]水平。结果 研究共纳入90例SDV患者,GIS组和BX组分别为49例和41例。GIS组治疗总有效率显著高于BX组(P <0.05)。GIS组听力恢复时间、耳鸣缓解时间和眩晕缓解时间均显著短于BX组(P <0.05)。治疗前,两组血清TNF-α、Hs-CRP和IL-6差异无统计学意义(P> 0.05);治疗后,两组血清TNF-α、Hs-CRP和IL-6水平均较治疗前显著下降(P <0.05);且GIS组水平均低于BX组(P <0.05)。两组不良反应发生率差异无统计学意义(P> 0.05)。结论 GIS联合BX治疗SDV患者疗效显著,可缩短患者听力恢复、耳鸣缓解及眩晕缓解时间,其可能与GIS和BX降低机体炎症水平有关。 展开更多
关键词 突发性耳聋 金纳多注射液 巴曲酶 炎症因子 安全性
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面向突发性水污染事件的多传感器动态组网立体监测
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作者 申邵洪 姜莹 +3 位作者 陈希炽 向大享 陈喆 文雄飞 《长江科学院院报》 CSCD 北大核心 2024年第3期160-165,共6页
针对突发性水污染事件应急监测和智能模拟分析需求,研究了多传感器立体协同监测模型,建立了突发性水污染事件的时间、空间属性和传感器观测性能之间的相关关系,实现了卫星、无人机、地面、水上平台的动态、协同组网。在丹江口库区开展... 针对突发性水污染事件应急监测和智能模拟分析需求,研究了多传感器立体协同监测模型,建立了突发性水污染事件的时间、空间属性和传感器观测性能之间的相关关系,实现了卫星、无人机、地面、水上平台的动态、协同组网。在丹江口库区开展了突发性水污染事件动态组网立体监测实验分析,根据水污染事件发生时、动态演变过程中和事件后期3个阶段的不同观测需求,基于多传感器立体协同监测模型,深入开展了多传感器协同优化求解,确定了相应的观测平台及传感器。实验结果表明,协同、高效的“天空地一体化”立体感知网能够全面、精准、快速获取水污染事件监测信息,可以科学支撑突发性水污染事件的应急处置。 展开更多
关键词 突发性水污染事件 动态组网 立体监测 多传感器
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一起输入性猪繁殖与呼吸综合征疫情的紧急流行病学调查
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作者 吴雪军 张传亮 +1 位作者 刘俐君 李盛琼 《中国动物检疫》 CAS 2024年第5期20-24,共5页
自2023年6月4日开始,四川省金堂县某生猪代养场引进的仔猪陆续出现异常死亡情况。为确定病因,分析来源,评估传播风险,赴现场开展了紧急流行病学调查。该猪场于2023年5月20—30日分4批共引进仔猪2200头,截至7月14日,共有222头仔猪发病,12... 自2023年6月4日开始,四川省金堂县某生猪代养场引进的仔猪陆续出现异常死亡情况。为确定病因,分析来源,评估传播风险,赴现场开展了紧急流行病学调查。该猪场于2023年5月20—30日分4批共引进仔猪2200头,截至7月14日,共有222头仔猪发病,124头死亡,袭击率为10.09%,病死率为55.86%。经现场临床诊断、病死猪病理剖检、实验室检测及干预治疗效果印证,综合判定病因为猪繁殖与呼吸综合征病毒感染。经追踪调查,该发病猪场无生猪调出,与该猪场有流行病学关联的其他猪场未出现类似发病情况,因此判定疫情扩散风险较低。溯源调查发现发病仔猪的来源种猪场曾发生过猪繁殖与呼吸综合征疫情,现场调查发现该发病猪场生产管理规范,且周边养殖场未出现猪只异常死亡情况,因此综合判定疫情由引进带毒仔猪引起。本起疫情警示,养殖场在引种前应先确认种源场的疾病流行情况,同时加强引种检疫,尽可能避免输入性疫情发生。 展开更多
关键词 紧急流行病学调查 猪繁殖与呼吸综合征 仔猪 猝死
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内耳三维真实重建反转恢复成像与突发性聋预后
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作者 张呈辉 王伟韬 +2 位作者 任芳芳 冀少杰 周鼎坤 《中华耳科学杂志》 CSCD 北大核心 2024年第1期53-57,共5页
目的分析突发性聋(突聋)患者的内耳三维真实重建反转恢复(three dimensional real inversion recovery,3D Real IR)成像表现,探讨内耳不同信号强度与突聋预后的关系。方法选取2022年9月25日—2023年4月10日郑州大学第五附属医院耳鼻咽... 目的分析突发性聋(突聋)患者的内耳三维真实重建反转恢复(three dimensional real inversion recovery,3D Real IR)成像表现,探讨内耳不同信号强度与突聋预后的关系。方法选取2022年9月25日—2023年4月10日郑州大学第五附属医院耳鼻咽喉科住院治疗及门诊治疗的单侧突聋患者60例,按照听力曲线将患者分为低频下降型4例、高频下降型1例、平坦下降型34例和全聋型21例。由于平坦下降型和全聋型治疗方法一致,将平坦下降型和全聋型的55例患者按治疗有效与否分为无效组25例和有效组30例;按治疗前听力分级,分为轻度听力损失组11例、中度听力损失组7例、重度听力损失组16例和极重度听力损失组21例;根据听力下降与否分为患耳组55耳和健耳组55耳。比较患耳和健耳的耳蜗信号强度,并测量延髓信号强度,分别计算耳蜗/延髓(cochlea/medulla ratio,CM)比值,分析耳蜗信号强度与治疗结果之间关系。结果无效组CM比值明显高于治疗有效组,差异有统计学意义(P<0.001);患耳组与健耳组CM比值比较,差异有统计学意义(P<0.05)。轻度、中度、重度和极重度听力损失组患耳CM比值比较(2.57±3.02 vs 1.77±0.87 vs 2.04±1.98 vs 2.51±2.33),差异无统计学意义(F=0.304,P=0.823)。结论内耳3D Real IR可显示突聋患者血-迷路屏障通透性的改变,CM比值可以更精确了解突聋患者内耳受损的程度,CM比值大小与听力损失程度并不一致,可以单独作为一种判断突聋预后的因素。突聋患者CM比值高于1.58提示可能预后不良。 展开更多
关键词 突发性聋 内耳三维真实重建反转恢复成像 耳蜗/延髓比值 预后
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运动后心率恢复与心源性猝死风险的相关性:一项队列研究的Meta分析
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作者 王晨阳 徐鹏 +3 位作者 郭治荣 王冬颖 李俊峡 曹雪滨 《中国循证心血管医学杂志》 2024年第4期398-402,共5页
目的通过Meta分析,综合分析运动后心率恢复(HRR)与心源性猝死(SCD)之间的关系。方法基于PubMed、Embase和Web of Science数据库,进行截至2024年1月2日的文献检索。队列研究关注于HRR和SCD间的风险关系,通过风险比(HR)及95%可信区间(CI)... 目的通过Meta分析,综合分析运动后心率恢复(HRR)与心源性猝死(SCD)之间的关系。方法基于PubMed、Embase和Web of Science数据库,进行截至2024年1月2日的文献检索。队列研究关注于HRR和SCD间的风险关系,通过风险比(HR)及95%可信区间(CI)进行评估。统计学分析采用Stata 12.0软件。结果纳入6项研究。固定效应模型(I^(2)=41.8%,P=0.112)的汇总结果显示:与心率恢复慢相比,心率恢复快人群发生SCD风险更低(HR=0.74,95%CI:0.64~0.86,P<0.001)。大多数亚组分析中都观察到了持续结果。排除一项研究并不影响总体结果[HR(95%CI):0.66(0.55,0.79)~0.76(0.65,0.88)]。Egger检验未发现明显的发表偏倚(P=0.059)。结论心率恢复较慢会增加普通人群发生SCD的风险。因此,HRR可能是临床实践中预防SCD的一个潜在靶点。 展开更多
关键词 心源性猝死 运动后心率恢复 荟萃分析 风险相关性
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