不同载荷条件下三种内固定方式治疗PauwelsⅢ型股骨颈骨折的有限元分析

背景:治疗PauwelsⅢ型股骨颈骨折的最佳内固定方式仍未达成共识,既往相关有限元分析大多采用单一简化载荷条件,对于常用内固定装置的生物力学特性还需进一步探究。目的:通过有限元方法分析空心加压螺钉、动力髋螺钉和股骨颈系统治疗PauwelsⅢ型股骨颈骨折在单腿站立载荷及侧方跌倒载荷条件下的生物力学特性。方法:通过CT扫描获取健康成人股骨DICOM数据,导入Mimics 15.0软件,得到骨组织的粗糙模型,再通过Geomagics软件对Mimics导出的数据进行优化处理,然后根据空心加压螺钉、动力髋螺钉和股骨颈系统的临床应用参数采用Pro/E软件建立3种内固定模型并与股骨模型组装,最后导入Ansys软件进行加载、计算,分析3种内固定模型在单腿站立载荷及侧方跌倒载荷的不同工况下股骨和内固定的应力分布和位移情况,以及股骨距和Ward三角区的应力特点。结果与结论:(1)单腿站立载荷及侧方跌倒载荷下,3种内固定模型的股骨近端应力均主要分布在股骨颈骨折端内上方,3种内固定模型的股骨近端、骨折端、Ward三角以及股骨距的应力峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(2)单腿站立载荷及侧方跌倒载荷下,3种内固定模型的股骨近端位移峰值均位于股骨头顶端,且位移峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(3)3种内固定模型在单腿站立及侧方跌倒载荷条件下内固定的位移峰值均位于内固定装置上方顶端,且位移峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(4)3种内固定模型在单腿站立及侧方跌倒载荷条件下内固定的应力均主要集中在内固定装置的骨折端附近区域,且内固定应力峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(5)结果表明,股骨颈系统的机械稳定性最佳,但是可能存在对于骨折端和股骨距应力遮挡的风险;股骨颈系统的内固定装置应力更为分散,内固定断裂风险更低。

一种用于可见光通信信号调制格式识别的改进YOLOv5s算法

针对可见光通信信号在传输中易受信道环境和背景噪声干扰等因素影响调制格式识别精度的问题,提出一种用于可见光通信信号调制格式识别的改进YOLOv5s(You Only Look Once)算法。首先,通过YOLOv5s算法网络输入端引入Mixup数据增强方式,将其与原网络中的Mosaic数据增强方式相结合,提升网络的鲁棒性,并增强算法在不同调制格式信号间的泛化能力;其次,将自适应空间特征融合(ASFF)引入到Neck网络中,充分提取不同层次的特征,提高检测精度。实验结果表明,在混合信噪比条件下,所提改进算法的平均精度均值(mAP)达到了0.903,比原始YOLOv5s算法提升了0.7%,且在信噪比为20 dB时mAP高达0.993。

能源资源计量在线审查系统设计与应用

能源资源计量在线审查系统可实现网上填报和审查,方便用能单位信息填报,提升政府部门能源计量工作的质量和效率,是新形势下能源资源领域计量监管模式的智慧创新,可为推行能源计量“智慧化+信用化+网格化”监管提供技术支撑。

Drug-eluting bead transarterial chemoembolization as neoadjuvant therapy pre-liver transplantation for advanced-stage hepatocellular carcinoma

BACKGROUND The objectives of this study were to assess the safety and efficacy of drug-eluting bead transarterial chemoembolization(DEB-TACE)as neoadjuvant therapy before liver transplantation(LT)for advanced-stage hepatocellular carcinoma(HCC)and to analyze the prognostic factors.AIM To determine whether DEB-TACE before LT is superior to LT for advanced-stage HCC.METHODS A total of 99 individuals diagnosed with advanced HCC were studied retrospectively.The participants were categorized into the following two groups based on whether they had received DEB-TACE before LT:DEB-TACE group(n=45)and control group(n=54).The participants were further divided into two subgroups based on the presence or absence of segmental portal vein tumor thrombus(PVTT).The DEB-TACE group consisted of two subgroups:Group A(n=31)without PVTT and group B(n=14)with PVTT.The control group also had two subgroups:Group C(n=37)without PVTT and group D(n=17)with PVTT.Data on patient demographics,disease characteristics,therapy response,and adverse events(AEs)were collected.The overall survival(OS)and recurrence-free survival(RFS)rates were assessed using Kaplan-Meier curves.Univariate and multivariate Cox regression analyses were conducted to determine the parameters that were independently related to OS and RFS.RESULTS The DEB-TACE group exhibited an overall response rate of 86.6%.Following therapy,there was a significant decrease in the median alpha-fetoprotein(AFP)level(275.1 ng/mL vs 41.7 ng/mL,P<0.001).The main AE was post-embolization syndrome.The 2-year rates of RFS and OS were significantly higher in the DEB-TACE group than in the control group(68.9%vs 38.9%,P=0.003;86.7%vs 63.0%,P=0.008).Within the subgroups,group A had higher 2-year rates of RFS and OS compared to group C(71.0%vs 45.9%,P=0.038;83.8%vs 62.2%,P=0.047).The 2-year RFS rate of group B was markedly superior to that of group D(64.3%vs 23.5%,P=0.002).Results from multivariate analyses showed that pre-LT DEB-TACE[hazard ratio(HR)=2.73,95%confidence interval(CI):1.44-5.14,P=0.04],overall target tumor diameter≤7 cm(HR=1.98,95%CI:1.05-3.75,P=0.035),and AFP level≤400 ng/mL(HR=2.34;95%CI:1.30-4.19,P=0.009)were significant risk factors for RFS.Additionally,pre-LT DEBTACE(HR=3.15,95%CI:1.43-6.96,P=0.004)was identified as a significant risk factor for OS.CONCLUSION DEB-TACE is a safe and efficient therapy for advanced-stage HCC and also enhances patient survival after LT.

基于不同高度异常交叉约束反演的航空磁法探测遗煤火区

煤矿采空区遗煤自燃过程中产生化学作用合成了高磁性的铁磁性矿物,表现为高磁异常。针对采空区遗煤自燃区的分布,利用探测高度越高越能有效突出更大深度自燃区的特点,来揭示不同深度的自燃区特征。建立不同高度航空磁法立体探测技术,采用交叉约束,实现不同高度航磁数据联合反演,进而获取自燃区的三维分布结构;结合围岩物性资料,从而确定采空区遗煤自燃区的具体分布范围。该方法可以提升不同深度场源的分辨率,更加准确地揭示深部火区的分布,为采空区遗煤自燃区治理及煤矿安全提供重要保障。

基于双重差分模型的科普信息化政策效果研究

基于2008-2020年28个省区市面板数据,构建科普能力创新指数指标体系来测量区域科普能力,采用PSM-DID评价政策效果,评估科普信息化政策是否影响了试点省份科普能力的提升。研究发现:科普信息化政策力度的加强,会促进试点省份科普能力发展指数的发展,从而促进科普能力发展。此外,还通过传导机制发现影响科普能力的不同影响因素,且科普政策的实施对科普能力发展指数的影响存在区域差异,其中相较于西部地区,东中部地区对科普政策的实施对科普能力发展指数的发展有更显著的影响。

孔间电阻率监测在注浆效果检测的应用研究

华北型煤田煤层底板岩溶水害防治的主要技术手段是对含水岩层进行注浆改造,目前注浆效果检测的手段主要是对注浆前后岩性特征进行分析,缺少对注浆全过程的跟踪动态监测,很难对注浆效果进行准确评价。针对上述问题,引入孔间电阻率监测系统对注浆改造岩层的电阻率变化特征进行全过程监测,以实现浆液扩散范围的精准探测。首先,采用改进电极和线缆装置将电阻率监测系统置于煤层底板长定向钻孔内,实现孔间的电阻率监测;然后,构建浆液扩散的地质模型,采用三维电阻率反演对模拟数据进行处理解释;最后,在煤矿井下注浆层位开展注浆全过程的孔间电阻率监测工程试验。模拟结果表明:孔间电阻率监测能识别浆液异常的扩散范围,根据电阻率随时间的变化趋势可推测浆液扩散范围,随着浆液逐渐扩散,异常区范围逐渐变大,异常强度逐渐增强。工程试验结果表明:通过钻孔将电阻率监测系统布置于注浆层位进行动态监测,监测数据经三维反演成像后能成功捕捉到浆液扩散导致的注浆层位电阻率变化特征,为煤矿注浆效果检测提供一种可行的技术方案。

Fast and Stable Zinc Anode‑Based Electrochromic Displays Enabled by Bimetallically Doped Vanadate and Aqueous Zn^(2+)/Na^(+)Hybrid Electrolytes

Vanadates are a class of the most promising electrochromic materials for displays as their multicolor characteristics.However,the slow switching times and vanadate dissolution issues of recently reported vanadates significantly hinder their diverse practical applications.Herein,novel strategies are developed to design electrochemically stable vanadates having rapid switching times.We show that the interlayer spacing is greatly broadened by introducing sodium and lanthanum ions into V_(3)O_(8)interlayers,which facilitates the transportation of cations and enhances the electrochemical kinetics.In addition,a hybrid Zn^(2+)/Na^(+)electrolyte is designed to inhibit vanadate dissolution while significantly accelerating electrochemical kinetics.As a result,our electrochromic displays yield the most rapid switching times in comparison with any reported Zn-vanadate electrochromic displays.It is envisioned that stable vanadate-based electrochromic displays having video speed switching are appearing on the near horizon.

An overview of recent progress in the development of flexible electrochromic devices

Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,nonemissive displays,optical filters,among others.Although the current rigid electrochromic devices have shown emerging interest and developed rapidly,many applications(e.g.,wearable/deformable optoelectronics)are blocked due to their inflexible features.Herein,the adaption of rigid electrochromic devices to flexible ones is of particular interest for the new era of smart optoelectronics.In this review,the current state-of-the-art achievements of flexible electrochromic devices(FECDs)are highlighted,along with their design strategies and the choice of electrochromic materials.The recent research progress of FECDs is reviewed in detail,and the challenges and corresponding solutions for real-world applications of FECDs are discussed.Furthermore,we summarize the basic fabrication strategies of FECDs and their potential applications.In addition,the development trend,the perspectives,and the outlook of FECDs are discussed at the end of this Review,which may provide recommendations and potential directions to advance the practical applications of FECDs.

双向入路治疗下肢动脉远端流出道闭塞性病变

目的探讨膝下动脉逆行穿刺建立双向入路治疗下肢动脉远端流出道闭塞性病变的技术特点、安全性和有效性。方法回顾性分析2018年1月至2019年3月47例患者临床资料,均为顺行入路开通血管失败的腘动脉和远端膝下动脉闭塞,中转采用远端动脉逆行穿刺建立双通路开通血管。结果技术总成功率为100%(47/47)。无死亡、截肢等严重并发症发生,穿刺并发症发生率为12.8%。术后6、12个月累计通畅率分别为70.5%(31/44)、43.2%(19/44)。结论在远端血管解剖条件允许下,双向入路治疗下肢动脉远端流出道闭塞性病变能提高血管开通率,并发症发生率低,近期保肢率高。

环境光和邻牙对前牙接触式测色仪测色结果的影响

目的探讨外源性环境光和邻牙对接触式测色仪测量牙齿颜色结果的影响。方法将10颗离体上颌中切牙固定,MI-150光源从牙齿的唇面(切缘朝下)3点钟和12点钟上方45°入射,入射强度分别为0、50、75、100、125、150W,在有邻牙和无邻牙时分别测量10颗离体中切牙中1/3正中点的CIEL﹡a﹡b﹡值,测量结果采用SPSS11.5软件进行统计分析。结果不同强度和方向的入射光及邻牙存在与否对颜色测量结果均没有明显影响(P>0.05)。结论环境光源和邻牙对接触式测色仪的测色结果没有影响,临床上在牙椅外源辅助灯光下可以采用接触式测色仪直接测色。

装载硐室加固及数值模拟研究

针对崔家沟矿井底煤仓装载硐室围岩变形破坏及其主体悬挂给煤机的混凝土造成破坏特点,在原有结构基础上,提出壁后注浆、锚索加固、混凝土结构粘钢补强及下方支设钢管砼立柱相结合的方法来控制硐室围岩和梁的变形破坏,改善应力分布,提高混凝土结构的承载能力。并利用数值模拟软件分析了加固前后围岩及结构的应力和变形情况,论证了该加固方案的可行性。

水库下伏采空区覆岩裂隙探查与综合防治技术

以火石咀煤矿8712工作面采空区注浆充填治理工程为背景,基于开采沉陷理论,利用钻孔波速测试和压水试验,阐明了综放开采后上覆岩层裂隙发育特征。结果表明:综放开采后上覆岩层整体移动过程中,岩体完整性受到不同程度破坏,采空区边缘处形成呈带状分布水平宽度约60 m的张拉断裂带。采用"库底防渗、采空区充填注浆、影响区域残余变形监测"的综合防治技术,取得良好治理效果。

雷公藤红素对高糖诱导的H9C2细胞损伤的保护作用

目的:通过高糖条件培养大鼠心肌H9C2细胞模拟糖尿病心肌病(DCM)体外细胞模型,并探讨雷公藤红素对H9C2细胞的保护作用及机制。方法:实验设立低糖组(5.6 mmol/L低糖培养)、等渗组(甘露醇等渗培养)、高糖组(30 mmol/L高糖培养)和雷公藤红素组(高糖培养并加入10 ng/mL和100 ng/mL雷公藤红素干预)。采用MTT法分析高糖组和雷公藤红素组H9C2细胞的活力;应用活性氧簇荧光探针染色法和流式细胞术分析低糖组、等渗组、高糖组和100 ng/m L雷公藤红素组H9C2细胞中ROS产生水平;RT-PCR和Western blot实验技术分析低糖组、等渗组、高糖组和雷公藤红素组H9C2细胞中NF-κB、TGF-1β和IL-1β的mRNA和蛋白表达水平。结果:高糖组中高糖培养条件对H9C2细胞活力有抑制作用,与低糖组和等渗组比差异有统计学意义(P<0.05),雷公藤红素干预可以降低高糖培养对H9C2细胞的生长抑制作用;高糖组细胞内的ROS水平明显高于低糖组和等渗组(P<0.05),100 ng/m L雷公藤红素可抑制细胞内ROS产生;RT-PCR和Western blot结果显示,与低糖组和等渗组相比,高糖组细胞中NF-κB、TGF-1β和IL-1βm RNA和蛋白表达上调,差异有统计学意义(P<0.05);与高糖组相比,10 ng/mL和100 ng/mL雷公藤红素组细胞中的NF-κB、TGF-1β和IL-1β基因mRNA和蛋白表达水平均出现下调,差异有统计学意义(P<0.05)。结论:雷公藤红素可以明显抑制H9C2细胞在高糖培养条件下ROS的产生水平并降低高糖培养对细胞的生长抑制作用,发挥对心肌细胞的保护作用,其机制可能与抑制炎症因子相关基因的表达有关。

Effect of orthodontic force on inflammatory periodontal tissue remodeling and expression of IL-6 and IL-8 in rats

Objective:To investigate effect of orthodontic force on inflammatory periodontal tissue remodeling and expression of IL-6 and IL-8 in rats.Methods:Eighty SD rats were randomly divided into 4 groups,blank control group(group A)with 5 rats,treatment normal group(group B)with 25 rats,inflammation control group(group(group C)with 25 rats,inflammation treatment group(group D)with 25 rats.Immunohistochemistry and histomorphometric analysis was performed to measure the expression of IL-6,IL-8 and the firet molar to the recent movement in the distance.Results:The expression of IL-8 reached a maximum on day 5 and declined thereafter in group B;the expression of IL-6 reached a maximum on day 5 in group B.The expression of IL-6 and IL-8 was gradually weakened with time in group C.The expression of IL-6 and IL-8 were high,and reached a maximum on day 5 and declined thereafter in group D.AD of positive cells in group D were higher than group B at each time point(P<0.05).The time which 0.49 N orthodontic force was loaded was longer,orthodontic tooth movement distance was greater.Movement distance in group D were longer than group B(P<0.05).Conclusions:Orthodontic force as well as inflammatory stimulus can evoke the expression of IL-6 and IL-8.Under the combined effects of inflammation and orthodontic force,the expression of IL-6,IL-8will increase.

Hangzhou criteria as downstaging criteria in hepatocellular ca

Background:The downstaging of hepatocellular carcinoma(HCC)has been confirmed to benefit liver transplantation(LT)patients whose tumors are beyond the transplantation criteria.Milan criteria(MC),a tumor size and number-based assessment,is currently used as the endpoint in these patients.However,many studies believe that tumor biological behavior should be added to the evaluation criteria for downstaging efficacy.Hence,this study aimed to explore the feasibility of Hangzhou criteria(HC),which introduced tumor grading and alpha-fetoprotein in addition to tumor size and number,as an endpoint of downstaging.Methods:We performed a multicenter and retrospective study of 206 patients accepted locoregional therapy(LRT)as downstaging/bridge treatment prior to LT in three centers of China.Results:Recipients were divided into four groups:failed downstaging to the HC(group A,n=46),successful downstaging to the HC(group B,n=30),remained within the HC all the time(group C,n=113),and tumor progressed(group D,n=17).The 3-year HCC recurrence probabilities of groups B and C were not significantly different(10.3%vs.11.6%,P=0.87).The HCC recurrent rate was significantly higher in group A(52.3%)compared with that in group B/C(P<0.05).Seven patients(7/76,9.2%)whose tumor exceeded the the HC were successfully downstaged to the MC,and 39.5%(30/76)to the the HC.In group B,23 patients remained beyond the MC and their survivals were as well as those of patients within the MC.Conclusions:Compared to the MC,HC downstaging criteria can give more HCC patients access to LT and furthermore,the outcome of these patients is the same as those matching MC downstaging criteria.Hangzhou downstaging criteria therefore is applicable in clinical practice.

Safety and efficacy of an integrated endovascular treatment strategy for early hepatic artery occlusion after liver transplantation

Background:Hepatic artery occlusion(HAO)after liver transplantation(LT)is typically comprised of hepatic artery thrombosis(HAT)and stenosis(HAS),both of which are severe complications that coexist and interdependent.This study aimed to evaluate an integrated endovascular treatment(EVT)strategy for the resolution of early HAO and identify the risk factors associated with early HAO as well as the procedural challenge encountered in the treatment strategy.Methods:Consecutive orthotopic LT recipients(n=366)who underwent transplantation between June 2017 and December 2018 were retrospectively investigated.EVT was performed using an integrated strategy that involved thrombolytic therapy,shunt artery embolization plus vasodilator therapy,percutaneous transluminal angioplasty,and/or stent placement.Simple EVT was defined as the clinical resolution of HAO by one round of EVT with thrombolytic therapy and/or shunt artery embolization plus vasodilator therapy.Otherwise,it was defined as complex EVT.Results:Twenty-six patients(median age 52 years)underwent EVT for early HAO that occurred within 30 days post-LT.The median interval from LT to EVT was 7(6–16)days.Revascularization time(OR=1.027;95%CI:1.005–1.050;P=0.018)and the need for conduit(OR=3.558;95%CI:1.241–10.203,P=0.018)were independent predictors for early HAO.HAT was diagnosed in eight patients,and four out of those presented with concomitant HAS.We achieved 100%technical success and recanalization by performing simple EVT in 19 patients(3 HAT+/HAS-and 16 HAT-/HAS+)and by performing complex EVT in seven patients(1 HAT+/HAS-,4 HAT+/HAS+,and 2 HAT-/HAS+),without major complications.The primary assisted patency rates at 1,6,and 12 months were all 100%.The cumulative overall survival rates at 1,6,and 12 months were 88.5%,88.5%,and 80.8%,respectively.Autologous transfusion<600 mL(94.74%vs.42.86%,P=0.010)and interrupted suture for hepatic artery anastomosis(78.95%vs.14.29%,P=0.005)were more prevalent in simple EVT.Conclusions:The integrated EVT strategy was a feasible approach providing effective resolution with excellent safety for early HAO after LT.Appropriate autologous transfusion and interrupted suture technique helped simplify EVT.

基于Rhino^(3D)-FLAC^(3D)耦合技术的库区下伏综放采煤沉陷区稳定性分析

为了定性、定量地分析库区水体荷载对综放采煤沉陷区稳定性的影响程度,以红岩河水库下伏采煤沉陷区为研究对象,通过Rhino^(3D)-FLAC^(3D)耦合技术快速构建三维数值模型,结合现场试验,研究了综放采煤沉陷区覆岩裂隙发育特征及库区水体荷载对采煤沉陷区覆岩稳定性的影响。结果表明:8712综放采煤沉陷区覆岩导水断裂带整体呈"马鞍"状,最大发育高度为138.24 m;库区水体荷载作用下采煤沉陷区地表垂向位移增加334.7 mm,导水断裂带发育高度增加3.76 m。

工作面采动影响下底板破坏深度微震规律

采用KJ959微震监测系统对朱庄煤矿Ⅲ633工作面回采期间煤岩活动和导水裂隙带发育情况进行监测,分析了微震活动能量、时间分布、发育高度以及空间分布规律,结果表明:微震事件数量和能量与开采活动密切相关;回采期间微震事件以顶板事件为主;底板最大破坏深度为25~30m,未波及到主要含水层,顶板裂隙发育高度为顶板上37m范围内,裂采比约为13.2。研究结果可为后续采煤和进一步制定矿井防治水方案提供参考。

Manufacture and Cytotoxicity of a Lead-free Piezoelectric Ceramic as a Bone Substitute—Consolidation of Porous Lithium Sodium Potassium Niobate by Cold Isostatic Pressing

Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing （CIP） was applied to fabricate porous lithium sodium potassium niobate （Li0.06Na0.5K0.44） NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague- Dawley rats were examined by a scanning electron microscopy （SEM） and metbylthiazol tetrazolium （MTT） assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute.