Atmospheric pressure plasma jet deposition of TiO_(2)layer on alumina/epoxy to improve electrical properties

In gas-insulated lines,basin-insulators can accumulate charge under non-uniform electric fields,distorting the field distribution and potentially causing surface flashover,which threatens the stability of power systems.In this study,Atmospheric Pressure Plasma Jet(APPJ)technology was used to deposit TiO_(2)on the surface of alumina/epoxy(Al_(2)O_(3)/EP)composites.The impact of deposition of TiO_(2)layer on the surface morphology and chemical composition of Al_(2)O_(3)/EP was studied using testing methods such as Scanning Electron Microscope,X-ray photoelectron spectroscopy,Fourier Transform Infrared Spectrometer,and Energy Dispersive Spectrometer.It was found that APPJ creates a dense,rough Ti-O layer on the Al_(2)O_(3)/EP surface,which bonds tightly with the substrate.The efficacy of APPJ was found to depend on processing time,with optimal results observed at 3 min,DC and AC flashover voltages increased by 29.6% and 15.7%,respectively.TiO_(2)layer enhances the conductivity of the resin and shallows trap levels.Through the synergistic effects of various factors,surface charges are efficiently dissipated and evenly distributed.This study not only reveals the physicochemical process of TiO_(2)deposition via APPJ but also integrates surface characteristics with electrical performance.The findings offer a new strategy to enhance surface flashover voltage and ensure equipment safety.

Necroptosis contributes to non-alcoholic fatty liver disease pathoetiology with promising diagnostic and therapeutic functions

Nonalcoholic fatty liver disease(NAFLD)is the most prevalent type of chronic liver disease.However,the disease is underappreciated as a remarkable chronic disorder as there are rare managing strategies.Several studies have focused on determining NAFLD-caused hepatocyte death to elucidate the disease pathoe-tiology and suggest functional therapeutic and diagnostic options.Pyroptosis,ferroptosis,and necroptosis are the main subtypes of non-apoptotic regulated cell deaths(RCDs),each of which represents particular characteristics.Considering the complexity of the findings,the present study aimed to review these types of RCDs and their contribution to NAFLD progression,and subsequently discuss in detail the role of necroptosis in the pathoetiology,diagnosis,and treatment of the disease.The study revealed that necroptosis is involved in the occurrence of NAFLD and its progression towards steatohepatitis and cancer,hence it has potential in diagnostic and therapeutic approaches.Nevertheless,further studies are necessary.

阿柏西普治疗新生血管性年龄相关性黄斑变性的应用进展

阿柏西普是一种人重组融合蛋白,作为一种可溶性血管内皮生长因子(VEGF)家族诱饵受体,包括VEGF-A、VEGF-B和胎盘生长因子(PLGF),从而抑制这些受体介导的下游信号。与雷珠单抗和贝伐单抗相比,阿柏西普与VEGF-A的所有亚型均具有更高的亲和力。阿柏西普已被批准用于治疗新生血管性年龄相关性黄斑变性(nARMD),国外大量临床研究显示其能很好地改善患者最佳矫正视力,减轻黄斑水肿和降低并发症,成为治疗nARMD患者的另一个选择,然而国内大样本应用时间尚短,国内相关研究较少,本文对阿柏西普治疗nARMD的临床应用进行综述。

乙型肝炎病毒相关慢加急性肝衰竭评分模型及检验参数对诊断及预后影响的研究进展

乙肝相关慢加急性肝衰竭(hepatitis B virus relatedacute-on-chronic liver failure,HBV-ACLF)是肝衰竭的常见类型,可发生在慢性乙型病毒性肝炎或肝硬化代偿期或失代偿期的基础上,其病情进展快速,常合并肝、脑、心、肾、凝血等多器官功能衰竭的临床综合征,病死率极高.美国胃肠病学会(American Gastroenterological Association,ACG)将其定义为具有潜在可逆性疾病,早期诊断,规范治疗,将极大影响其预后.近年来,一些新的评分模型及生物标志物的临床应用,有效提高了对HBV-ACLF的诊断及预后判断.本文对目前临床应用较广的评分模型及检验参数进行了梳理,进一步探讨其对HBV-ACLF的诊断和预后影响的价值.

Combined effect of repetitive transcranial magnetic stimulation and physical exercise on cortical plasticity

Physical exercise can minimize dysfunction and optimize functional motor recovery after stroke by modulating cortical plasticity.However,the limitation of physical exercise is that large amounts of time and effort are necessary to significantly improve motor function,and even then,substantial exercise may not be sufficient to normalize the observed improvements.Thus,interventions that could be used to strengthen physical exercise-induced neuroplasticity may be valuable in treating hemiplegia after stroke.Repetitive transcranial magnetic stimulation seems to be a viable strategy for enhancing such plasticity.As a non-invasive cortical stimulation technique,repetitive transcranial magnetic stimulation is able to induce longterm plastic changes in the motor system.Recently,repetitive transcranial magnetic stimulation was found to optimize the plastic changes caused by motor training,thereby enhancing the long-term effects of physical exercise in stroke patients.Therefore,it is believed that the combination of repetitive transcranial magnetic stimulation and physical exercise may represent a superior method for restoring motor function after stroke.

Plasma exchange-centered artificial liver support system in hepatitis B virus-related acute-onchronic liver failure:a nationwide prospective multicenter study in China

BACKGROUND： Plasma exchange （PE）-centered artificial liver support system reduced the high mortality rate of hepa titis B virus （HBV）-related acute-on-chronic liver failure （ACLF）. But the data were diverse in different medical centers. The present prospective nationwide study was to evaluate the effects of PE on patients with HBV-ACLF at different stages.

Daclatasvir plus asunaprevir in treatment-na?ve patients with hepatitis C virus genotype 1b infection

AIM To assess daclatasvir plus asunaprevir(d UAL) in treatment-na?ve patients from China's Mainland, Russia and South Korea with hepatitis C virus(HCV) genotype 1 b infection. METHODS Patients were randomly assigned(3:1) to receive 24 wk of treatment with d UAL(daclatasvir 60 mg once daily and asunaprevir 100 mg twice daily) beginning on day 1 of the treatment period(immediate treatment arm) or following 12 wk of matching placebo(placebodeferred treatment arm). The primary endpoint was a comparison of sustained virologic response at posttreatment week 12(SVR12) compared with the historical SVR rate for peg-interferon plus ribavirin(70%) among patients in the immediate treatment arm. The first 12 wk of the study were blinded. Safety was assessed in d UAL-treated patients compared with placebo patients during the first 12 wk(doubleblind phase), and during 24 wk of d UAL in both arms combined.RESULTS In total, 207 patients were randomly assigned to immediate(n = 155) or placebo-deferred(n = 52) treatment. Most patients were Asian(86%), female(59%) and aged < 65 years(90%). Among them, 13% had cirrhosis, 32% had IL28 B non-CC genotypes and 53% had baseline HCV RNA levels of ≥ 6 million IU/m L. Among patients in the immediate treatment arm, SVR12 was achieved by 92%(95% confidence interval: 87.2-96.0), which was significantly higher than the historical comparator rate(70%). SVR12 was largely unaffected by cirrhosis(89%), age ≥ 65 years(92%), male sex(90%), baseline HCV RNA ≥ 6 million(89%) or IL28 B non-CC genotypes(96%), although SVR12 was higher among patients without(96%) than among those with(53%) baseline NS5 A resistanceassociated polymorphisms(at L31 or Y93 H). during the double-blind phase, aminotransferase elevations were more common among placebo recipients than among patients receiving d UAL. during 24 wk of d UAL therapy(combined arms), the most common adverse events(≥ 10%) were elevated alanine aminotransferase and upper respiratory tract infection; emergent grade 3-4 laboratory abnormalities were infrequently observed, and all grade 3-4 aminotransferase abnormalities(alanine aminotransferase, n = 9; aspartate transaminase, n = 6) reversed within 8-11 d. Two patients discontinued d UAL treatment; one due to aminotransferase elevations, nausea, and jaundice and the other due to a fatal adverse event unrelated to treatment. There were no treatment-related deaths.CONCLUSION d UAL was well-tolerated during this phase 3 study, and SVR12 with d UAL treatment(92%) exceeded thehistorical SVR rate for peg-interferon plus ribavirin of 70%.

Bacterial infection triggers and complicates acute-on-chronic liver failure in patients with hepatitis B virus-decompensated cirrhosis: A retrospective cohort study

BACKGROUND Reports on bacterial infection(BI)in decompensated cirrhosis(DC)is mainly from alcoholic cirrhosis.The role of BI as a trigger or complication of acute-onchronic liver failure(ACLF)in patients with hepatitis B virus decompensated cirrhosis(HBV-DC)remains to be investigated.AIM To investigate the impact of BI on the outcomes of the patients with HBV-DC admitted into the hospital with or without ACLF.METHODS This retrospective study included patients with HBV-DC admitted to two tertiary centers in China.In-hospital overall survival,90-d transplant-free survival,5-year post-discharge survival,and cumulative incidence of ACLF were evaluated.Risk factors for death were analyzed considering liver transplantation as a competing event.RESULTS A total of 1281 hospitalized HBV-DC patients were included;284 had ACLF at admission.The overall prevalence of BI was 28.1%.The patients with BI had a significantly lower in-hospital survival and transplant-free 90-d survival than those without,in both the patients admitted with and without ACLF.The presence of BI significantly increased the risk of developing ACLF[subdistribution hazard ratio(sHR)=2.52,95%CI:1.75-3.61,P<0.001]in the patients without ACLF.In the patients discharged alive,those who had an episode of BI had a significantly lower 5-year transplant-free survival.BI was an independent risk factor for death in the patients admitted without ACLF(sHR=3.28,95%CI:1.93-5.57),while in ACLF admissions,the presence of pneumonia,but not other type of BI,independently increased the risk of death(sHR=1.87,95%CI:1.24-2.82).CONCLUSION BI triggers ACLF in patients with HBV-DC and significantly impairs short-term survival.HBV-DC patients should be monitored carefully for the development of BI,especially pneumonia,to avoid an adverse outcome.

Serum soluble ST2 is a promising prognostic biomarker in HBV-related acute-on-chronic liver failure

BACKGROUND： The IL-33/ST2 axis is involved in the pathogenesis of many diseases such as autoimmune diseases, cancer,and heart failure. However, studies of the IL-33/ST2 pathway in HBV-related acute-on-chronic liver failure（HBV-ACLF） are lacking. The present study aimed to determine the prognostic role of serum IL-33/soluble ST2（s ST2） in HBV-ACLF.METHODS： Serum levels of IL-33 and sS T2 in healthy controls（HC, n=18）, chronic hepatitis B（CHB, n=27） and HBV-ACLF（n=51） patients at the 1st and 4th week after enrollment were detected using ELISA, and clinical data were collected. The follow-up of HBV-ACLF patients lasted for 6 months at least.RESULTS： There was no significant difference of serum IL-33 level among HC, CHB and HBV-ACLF patients at week 1.However, serum s ST2 level differed significantly among the three groups： highest in the HBV-ACLF group, moderate in the CHB group and lowest in the HC group. There was a reverse correlation between serum s ST2 level and the survival of HBV-ACLF patients. The level of serum s ST2 in HBV-ACLF survivors was significantly declined from week 1 to week 4 following the treatment, whereas that in HBV-ACLF nonsurvivors remained at a high level during the same period. Furthermore, serum sS T2 level was significantly correlated with laboratory parameters and the most updated prognostic scores（CLIF-C OF score, CLIF-C ACLF score and ACLF grades）. Thereceiver operating characteristics curves demonstrated that serum sS T2 level was a good diagnostic marker for predicting the 6-month mortality in HBV-ACLF patients, comparable to the most updated prognostic scores. Serum sS T2 cut-off points for predicting prognosis in HBV-ACLF patients were 76 ng/mL at week 1 or 53 ng/mL at week 4, respectively. HBV-ACLF patients with serum sS T2 level above the cut-off point often had a worse prognosis than those below the cut-off point.CONCLUSION： Serum s ST2 may act as a promising biomarker to assess severity and predict prognosis of patients with HBV-ACLF and help for the early identification and optimal treatment of HBV-ACLF patients at high risk of mortality.

抗VEGF治疗在眼科的临床意义及研究进展

目前许多抗血管内皮生长因子(VEGF)药物被用于治疗各种眼科疾病,尤其在血管增生性眼病的治疗中扮演着重要角色,这些药物能够明显抑制新生血管且减轻水肿提高患者视力,但其长期治疗效果需要更长远的随访和研究。本文就抗VEGF在眼科的应用及研究进展进行综述,为临床应用和深入研究提供参考。

Double-target neural circuit-magnetic stimulation improves motor function in spinal cord injury by attenuating astrocyte activation

Multi-target neural circuit-magnetic stimulation has been clinically shown to improve rehabilitation of lower limb motor function after spinal cord injury. However, the precise underlying mechanism remains unclear. In this study, we performed double-target neural circuit-magnetic stimulation on the left motor cortex and bilateral L5 nerve root for 3 successive weeks in a rat model of incomplete spinal cord injury caused by compression at T10. Results showed that in the injured spinal cord, the expression of the astrocyte marker glial fibrillary acidic protein and inflammatory factors interleukin 1β, interleukin-6, and tumor necrosis factor-α had decreased, whereas that of neuronal survival marker microtubule-associated protein 2 and synaptic plasticity markers postsynaptic densification protein 95 and synaptophysin protein had increased. Additionally, neural signaling of the descending corticospinal tract was markedly improved and rat locomotor function recovered significantly. These findings suggest that double-target neural circuit-magnetic stimulation improves rat motor function by attenuating astrocyte activation, thus providing a theoretical basis for application of double-target neural circuit-magnetic stimulation in the clinical treatment of spinal cord injury.

Response-guided treatment of cirrhotic chronic hepatitis B patients: Multicenter prospective study

AIM: To observe the effect of response-guided add-on therapy with adefovir(ADV) and lamivudine(LAM) in cirrhotic hepatitis B(CHB) patients.METHODS: A total of 100 patients with CHB and cirrhosis were divided into three arms according to hepatitis B virus(HBV) DNA level after 24 wk LAM monotherapy: Arm A(complete response, HBV DNA ≤ 60 IU/m L, n = 49), Arm B(partial response, HBV DNA: 60-2000 IU/m L, n = 31) and Arm C(inadequate response, HBV DNA > 2000 IU/m L, n = 20). ADV was added to LAM at week 48 in Arms A and B, but at week 24 in Arm C. Virological response, YMDD mutations, biochemical response, and liver function were evaluated.RESULTS: Comparison of the three arms demonstrated that early complete virologic response at week 24was associated with maintained viral suppression(undetectable rate of HBV DNA at week 144 was 95.96%, 66.67% and 35.29%, respectively, P = 0.000) and reduced YMDD mutations(mutation rate at week 144 was 0%, 3.23% and 15%, respectively, P = 0.015) after 144 wk treatment. For patients who failed to achieve complete virological response at week 24, switching to combination therapy further decreased HBV DNA level by 1 log10 IU/m L. All three arms obtained biochemical benefits including decline of alanine aminotransferase and elevation of albumin. In patients who developed HBV DNA breakthrough for YMDD mutations, ADV add-on therapy did not induce further multiple drug resistance to LAM or ADV.CONCLUSION: Optimized response-guided add-on therapy of ADV and LAM maintains long-term suppression of HBV DNA and improves liver function in CHB patients with compensated liver cirrhosis.

Safety and effectiveness of electromyography-induced rehabilitation treatment after epidural electrical stimulation for spinal cord injury:study protocol for a prospective,randomized,controlled trial

Epidural electrical stimulation is a new treatment method for spinal cord injury(SCI).Its efficacy and safety have previously been reported.Rehabilitation treatment after epidural electrical stimulation is important to ensure and improve the postoperative efficacy of epidural electrical stimulation in patients with SCI.Considering that electromyography(EMG)-induced rehabilitation treatment can accurately match the muscle contraction of patients with SCI,we designed a study protocol for a prospective,randomized controlled trial.In this trial,on the premise of adjusting the spinal cord electrical stimulator to obtain the maximum EMG signal of the target muscle,patients with SCI receiving epidural electrical stimulation will undergo EMG-induced rehabilitation treatment.Recovery of muscle strength of key muscles,quality of life,safety and therapeutic effects will be monitored.Twenty patients with SCI who are scheduled to undergo epidural electrical stimulation in Shanghai Ruijin Rehabilitation Hospital will be randomly divided into two groups with 10 patients per group.The control group will receive conventional rehabilitation treatment.The EMG-induced rehabilitation group will receive EMG-induced rehabilitation treatment of the target muscles of the upper and lower limbs based on conventional rehabilitation treatment.After rehabilitation treatment,follow up for all patients will occur at 2 weeks and 1,3 and 6 months.The primary outcome measure of this trial will be evaluation of target muscle recovery using the Manual Muscle Testing grading scale.Secondary outcome measures will include modified Barthel Index scores,integrated EMG values,the visual analogue scale,Spinal Cord Independence Measure scores,and modified Ashworth scale scores.The safety indicator will be the incidence of adverse events.This trial will collect data regarding the therapeutic effects of EMG-induced rehabilitation in patients with SCI receiving epidural electrical stimulation for 6 months after rehabilitation treatment.Findings from this trial will help develop rehabilitation methods in patients with SCI after epidural electrical stimulation.This study protocol was approved by Ethics Committee of Shanghai Ruijin Rehabilitation Hospital(Approval No.RKIRB2022-12)on February 15,2022 and was registered with Chinese Clinical Trial Registry(registration number:ChiCTR2200061674;date:June 30,2022).Study protocol version:1.0.

Resistin mediates the hepatic stellate cell phenotype

AIM: To describe the role of resistin in liver fibrosis. METHODS: For the in vivo animal study, Sprague Dawley rats were subjected to bile duct ligation (BDL) for 4 wk. Rat liver, adipose tissue (epididymal fat) and serum were analyzed for resistin expression. For the in vitro experiment, rat primary hepatic stellate cells (HSCs) and Kupffer cells (KCs) were used. HSCs were exposed to recombinant resistin, and collagenⅠ, transforming growth factor β1, α smooth muscle actin, tissue inhibitor of metalloproteinase 1 and connective tissue growth factor expression were analyzed. Resistin gene and protein expression was quantified as was the expression of pro-inflammatory cytokines including tumor necrosis factor α (TNFα), interleukin (IL)-1, IL-6, IL-8 and monocyte chemotactic protein-1 (MCP-1). The effects of resistin on HSC proliferation, migration and apoptosis were determined. The effects of resistin on KCs were also investigated. RESULTS: Following BDL, rat epididymal fat and serum rather than liver showed higher resistin expression compared to control rats. In liver, resistin was expressed in quiescent HSCs and KCs. Resistin treatment resulted in enhancement of TNFα , IL-6 , IL-8 and MCP-1 gene expression and increased IL-6 and MCP-1 protein in HSCs. Resistin activated HSC phospho-MAPK/p38, and p38 inhibition diminished IL-6 and MCP-1 expression. Furthermore, resistin facilitated HSC proliferation and migration, but decreased apoptosis which was via an IL-6 and MCP-1 mechanism. Finally, resistin-induced transforming growth factor β1 from KCs enhanced HSC collagenⅠexpression. CONCLUSION: Resistin directly and indirectly modulates HSC behavior towards a more pro-fibrogenic phenotype.

Hepatitis C virus cure with direct acting antivirals: Clinical,economic, societal and patient value for China

About 10 million people in China are infected with hepatitis C virus(HCV),with the seroprevalence of anti-HCV in the general population estimated at 0.6%.Delaying effective treatment of chronic hepatitis C(CHC)is associated with liver disease progression,cirrhosis,hepatocellular carcinoma,and liver-related mortality.The extrahepatic manifestations of CHC further add to the disease burden of patients.Managing CHC-related advanced liver diseases and systemic manifestations are costly for both the healthcare system and society.Loss of work productivity due to reduced well-being and quality of life in CHC patients further compounds the economic burden of the disease.Traditionally,pegylatedinterferon plus ribavirin(PR)was the standard of care.However,a substantial number of patients are ineligible for PR treatment,and only 40%–75%achieved sustained virologic response.Furthermore,PR is associated with impairment of patient-reported outcomes(PROs),high rates of adverse events,and poor adherence.With the advent of direct acting antivirals(DAAs),the treatment of CHC patients has been revolutionized.DAAs have broader eligible patient populations,higher efficacy,better PRO profiles,fewer adverse events,and better adherence rates,thereby making it possible to cure a large proportion of all CHC patients.This article aims to provide a comprehensive evaluation on the value of effective,curative hepatitis C treatment from the clinical,economic,societal,and patient experience perspectives,with a focus on recent data from China,supplemented with other Asian and international experiences where China data are not available.

Clinicopathological analysis of metaplastic meningioma: report of 15 cases in Huashan Hospital

Objective： Metaplastic meningioma is a rare subtype of benign meningiomas, classified as WHO grade I with well prognosis. Here we presented our experiences on 15 cases of metaplastic meningioma, to investigate the clinicopathological features, therapies and prognosis of these cases. Methods： 15 patients underwent surgical treatment for intracranial metaplastic meningioma between 2001 and 2010 at Neurosurgery Department of Huashan Hospital, Shanghai, China. The clinical data, radiological manifestation, treatment strategy, pathological findings and prognosis of all patients were analyzed retrospectively. Results： Among the 15 cases （10 males and 5 females）, the age ranged from 22 to 74 years old （the mean age was 50.67-year old）. The clinical manifestations include headache, dizziness, seizure attack, vision decrease, and weakness of bilateral lower limbs. All the patients received surgical treatment, combined with radiotherapy in some cases. In the follow-up period, recurrence occurred in 2 cases, of which 1 patient died of other system complications. Conclusions： Metaplastic meningiomas are characterized by focal or widespread mesenchymal differentiation with formation of bone, cartilage, fat, and xanthomatous tissue elements. Surgical removal is the optimal therapy, and the overall prognosis is well. But recurrence may occur in some cases, thus radiotherapy is necessary for such kind of patients.

Neural computational modeling reveals a major role of corticospinal gating of central oscillations in the generation of essential tremor

Essential tremor, also referred to as familial tremor, is an autosomal dominant genetic disease and the most common movement disorder. It typically involves a postural and motor tremor of the hands, head or other part of the body. Essential tremor is driven by a central oscillation signal in the brain. However, the corticospinal mechanisms involved in the generation of essential tremor are unclear. Therefore, in this study, we used a neural computational model that includes both monosynaptic and multisynaptic corticospinal pathways interacting with a propriospinal neuronal network. A virtual arm model is driven by the central oscillation signal to simulate tremor activity behavior. Cortical descending commands are classified as alpha or gamma through monosynaptic or multisynaptic corticospinal pathways, which converge respectively on alpha or gamma motoneurons in the spinal cord. Several scenarios are evaluated based on the central oscillation signal passing down to the spinal motoneurons via each descending pathway. The simulated behaviors are compared with clinical essential tremor characteristics to identify the corticospinal pathways responsible for transmitting the central oscillation signal. A propriospinal neuron with strong cortical inhibition performs a gating function in the generation of essential tremor. Our results indicate that the propriospinal neuronal network is essential for relaying the central oscillation signal and the production of essential tremor.

Improving the surface insulation of epoxy resin by plasma etching

Epoxy resin(EP)tends to accumulate a large amount of charge on its surface when exposed to a high-voltage DC electric field,which leads to a reduction in its insulative performance and an increase in potential safety risks in power systems.To suppress charge accumulation,improve the flashover voltage of the EP,and reduce the risk of gas insulated switchgear(GIS)/gas insulated transmission line(GIL)failure,we used two plasma-etching methods,i.e.,atmospheric-pressure dielectric barrier discharge(DBD)and the atmospheric-pressure plasma jet(APPJ),to modify the surface of the EP.The surface morphology and electrical properties of the modified materials were explored as a function of time.The results show that after DBD treatment,the roughness of the sample increases by 103.9 nm,the conductivity increases by3.9×10^(-18)S,and the flashover voltage increases by 14.4%;after APPJ treatment,the roughness of the sample increases by 223.5 nm,the conductivity increases by 3.4×10^(-17)S,and the flashover voltage increases by 18%.This shows that both plasma-etching methods can improve the insulation properties of materials by improving the surface-charge characteristics.The two methods are compared with each other:the APPJ treatment method is better at improving the surface roughness and electrical properties of materials,and this flexible treatment method has greater potential in industrial applications.

Effect of plasma step gradient modification on surface electrical properties of epoxy resin

In this paper,plasma fluorination is combined with plasma silicon deposition to achieve step gradient modification on an epoxy resin surface.The physicochemical characteristics of samples are investigated and the electrical performances measured.The obtained results show that compared with untreated and single treated samples,the samples treated by step gradient modification significantly improve the flashover performance.According to experiment and simulation,the mechanism explanations are summarized as follows.First,it is found that the step gradient conductivity can effectively optimize the electric field distribution of a needle-needle electrode.Then,step gradient modification suppresses the accumulation of surface charge at the triple junction and makes the charge distribution more uniform.Furthermore,it can accelerate the surface dissipation on a high electrical field region and control the dissipation rate on a low electrical field region.All these results can restrain surface discharge and increase the flashover voltage.The step gradient modification method proposed in this paper provides a new idea for improving the surface insulation performance.

Intraoperative ultrasound assistance in resection of intracranial meningiomas

Objective： Intracranial meningiomas, especially those located at anterior and middle skull base, are difficult to be completely resected due to their complicated anatomy structures and adjacent vessels. It＇s essential to locate the tumor and its vessels precisely during operation to reduce the risk of neurological deficits. The purpose of this study was to evaluate intraoperative ultrasonography in displaying intracranial meningioma and its surrounding arteries, and evaluate its potential to improve surgical precision and minimize surgical trauma. Methods： Between December 2011 and January 2013, 20 patients with anterior and middle skull base meningioma underwent surgery with the assistance of intraoperative ultrasonography in the Neurosurgery Department of Shanghai Huashan Hospital. There were 7 male and 13 female patients, aged from 31 to 66 years old. Their sonographic features were analyzed and the advantages of intraoperative ultrasonography were discussed. Results： The border of the rneningioma and its adjacent vessels could be exhibited on intraoperative ultrasonography. The sonographic visualization allowed the neurosurgeon to choose an appropriate approach before the operation. In addition, intraoperative ultrasonography could inform neurosurgeons about the location of the tumor, its relation to the surrounding arteries during the operation, thus these essential arteries could be protected carefully. Conclusions： Intraoperative ultrasonography is a useful intraoperative technique. When appropriately applied to assist surgical procedures for intracranial meningioma, it could offer very important intraoperative information （such as the tumor supplying vessels） that helps to improve surgical resection and therefore might reduce the postoperative morbidity.