不同固定方案的腰椎后路椎间融合术生物力学有限元分析

腰椎后路椎间融合术结合内固定系统已被广泛用于治疗腰椎滑脱等疾病。不同的内固定方案会使内固定系统和腰椎产生不同的力学响应,其结果会影响到内固定方案的选择。针对腰椎L5-S1骶骨节段轻度滑脱完全复位状态,在1例健康成年人腰椎模型的基础上,设计了3种不同节段的内固定手术方案:A组L5-S1融合固定、B组L4-L5-S1融合固定、C组L5-S1-S2融合固定,并建立相应的有限元模型。固定骶髂关节的耳状面,在L1椎体上表面施加垂直向下400 N的载荷和不同方向的7.5 N·m力矩,模拟脊柱前屈、后伸、侧弯和旋转等生理活动,比较不同方案模型中固定节段的钉棒应力情况、相邻近节段的椎间盘应力情况和各节段活动度的差异。结果表明,相比于A组模型,B组和C组模型的椎弓根螺钉和连接棒最大应力值较大;B组和C组椎间盘的应力最大值的集中区域明显大于A组;A组、B组和C组模型的腰椎活动总量较完整模型均有所减少。实验结果表明,采用A组L5-S1融合固定的方案可以降低内固定系统断裂的发生率,减少邻近节段椎间盘退变的发生率,在完成复位的情况下仍然可以保持一定的腰椎活动度,且A组方案的手术时间短、术中出血量少,是一种更优的内固定方案。

参数化腰骶有限元模型设计与验证

人体腰骶椎是承受载荷较大的部位,也是进行生物力学仿真研究的主要部位。为了提升腰骶椎部分建模的效率与灵活性,提出参数化腰骶有限元模型的建立方法。在CT图像中测取椎体的特征尺寸,并在工程建模软件中构建具有14个控制参数的L3-S1腰骶模型;同时通过三维重建法建立基于同一CT样本的腰骶重建模型。对两种模型施加相同的载荷并进行有限元分析,将仿真结果与文献报道的体外实验数据进行对比,验证了模型的有效性。基于有限元分析结果,比较了参数化模型和重建模型的椎间活动度、髓核最大应力等力学指标,结果表明,两种模型的力学指标均与文献中的实验或仿真数据接近,变化趋势与文献数据相似,即两种模型都是有效的;两种模型的椎间活动度、最大髓核内应力以及活动度随载荷大小的变化趋势等方面基本一致。以上结果说明所设计的参数化腰骶有限元模型能有效提升腰骶有限元建模与分析效率,在有限元分析中可替代重建模型。

基于无线Mesh的电力通信规划关键技术研究

本文旨在探索基于无线Mesh的电力通信规划关键技术。通过深入研究无线Mesh网技术特点、电力通信网络规划要点以及关键技术类别,提出了网络拓扑设计、通信质量保障、网络资源优化分配等创新方案。在应用方面,移动通信技术融合、电力通信规划智能创新和电力物联网场景规划创新,为系统提供了多层次的创新路径。研究结果显示,这些创新将使电力通信系统更智能、高效、可靠,从而促进电力系统在数字时代的快速发展。

Rapid instrument exchanging system for the Cassegrain focus of the Lijiang 2.4-m Telescope

As a facility used for astronomical research, the Lijiang 2.4-m telescope of Yunnan Astronomical Observatories, requires the ability to change one auxiliary instrument with another in as short a time as possible. This arises from the need to quickly respond to scientific programs （e.g. transient observation, time domain studies） and changes in observation conditions （e.g. seeing and weather conditions）. In this paper, we describe the design, construction and test of hardware and software in the rapid instrument exchange system （RIES） for the Cassegrain focal station of this telescope, which enables instruments to be quickly changed at night without much loss of observing time. Tests in the laboratory and at the telescope show that the image quality and pointing accuracy of RIES are satisfactory. With RIES, we observed the same Landolt standard stars almost at the same time with the Princeton Instruments VersArray 1300B Camera （PICCD） and the Yunnan Faint Object Spectrograph and Camera （YFOSC）, while both were mounted at the Cassegrain focus. A quasi-simultaneous comparison shows that the image quality of the optical system inside the YFOSC is comparable with that provided by the PICCD.

Response of glacier area variation to climate change in the Kaidu-Kongque river basin,Southern Tianshan Mountains during the last 20 years

Glaciers are crucial water resources for arid inland rivers in Northwest China.In recent decades,glaciers are largely experiencing shrinkage under the climate-warming scenario,thereby exerting tremendous influences on regional water resources.The primary role of understudying watershed scale glacier changes under changing climatic conditions is to ensure sustainable utilization of regional water resources,to prevent and mitigate glacier-related disasters.This study maps the current(2020)distribution of glacier boundaries across the Kaidu-Kongque river basin,south slope of Tianshan Mountains,and monitors the spatial evolution of glaciers over five time periods from 2000-2020 through thresholded band ratios approach,using 25 Landsat images at 30 m resolution.In addition,this study attempts to understand the role of climate characteristics for variable response of glacier area.The results show that the total area of glaciers was 398.21 km^(2)in 2020.The glaciers retreated by about 1.17 km^(2)/a(0.26%/a)from 2000 to 2020.The glaciers were reducing at a significantly rapid rate between 2000 and 2005,a slow rate from 2005 to 2015,and an accelerated rate during 2015-2020.The meteorological data shows slight increasing trends of mean annual temperature(0.02℃/a)and annual precipitation(2.07 mm/a).The correlation analysis demonstrates that the role of temperature presents more significant correlation with glacier recession than precipitation.There is a temporal hysteresis in the response of glacier change to climate change.Increasing trend of temperature in summer proves to be the driving force behind the Kaidu-Kongque basin glacier recession during the recent 20 years.

lncRNA和miRNA在肾脏纤维化中的作用

肾脏纤维化(renal fibrosis,RF)是导致慢性肾脏病终末期肾功能衰竭的一般病理过程,其分子机制复杂。长链非编码RNA(long non-coding RNA,lncRNA)及微小RNA(microRNA,miRNA)是主要的非编码RNA,可通过多种机制影响疾病进程、细胞内稳态和发育等。越来越多的研究显示lncRNA及miRNA对RF具有较高的应用价值,包括基于其开发RF的治疗方案,以及作为生物标志物用于RF的早期检测等。本文就lncRNA、miRNA及二者相互作用在RF中的研究进展进行综述。

Assessment of prediction model of the CPUE of neon flying squid with different sources of remote sensing data

Accurately building the relationship between the oceanographic environment and the distribution of neon flying squid(Ommastrephes bartramii)is very important to understand the potential habitat pattern of O.bartramii.However,when building the prediction model of O.bartramii with traditional oceanographic variables(e.g.,chlorophyll a concentration(Chl a)and sea surface temperature(SST))from space-borne observations,part of the important spectrum characteristics of the oceanic surface could be masked by using the satellite data products directly.In this study,the neglected remote sensing information(i.e.,spectral remote sensing reflectance(Rrs)and brightness temperature(BT))is firstly incorporated to build the prediction model of catch per unit effort(CPUE)of O.bartramii from July to December during 2014–2018 in the Northwest Pacific Ocean.Results show that both the conventional oceanographic variables and the neglected remote sensing data are suitable for building the prediction model,whereas the overall root mean square error(RMSE)of the predicted CPUE of O.bartramii with the former is typically less accurate than that with the latter.Hence,the Rrs and BT could be a more suitable data source than the Chl a and SST to predict the distribution of O.bartramii,highlighting that the potential value of the neglected variables in understanding the habitat suitability of O.bartramii.

An Exposure Meter of Lijiang Fiber-fed High-Resolution Spectrograph

In 2016,an exposure meter was installed on the Lijiang Fiber-fed High-Resolution Spectrograph to monitor the coupling of starlight to the science fiber during observations.Based on it,we investigated a method to estimate the exposure flux of the CCD in real time by using the counts of the photomultiplier tubes(PMT)of the exposure meter,and developed a piece of software to optimize the control of the exposure time.First,by using flat-field lamp observations,we determined that there is a linear and proportional relationship between the total counts of the PMT and the exposure flux of the CCD.Second,using historical observations of different spectral types,the corresponding relational conversion factors were determined and obtained separately.Third,the method was validated using actual observation data,which showed that all values of the coefficient of determination were greater than 0.92.Finally,software was developed to display the counts of the PMT and the estimated exposure flux of the CCD in real-time during the observation,providing a visual reference for optimizing the exposure time control.

多智能体模态逻辑系统K_n中的知识遗忘

如何让智能体像人一样具备遗忘的能力,目前仍然是人工智能所面临的最大挑战之一。遗忘在基于符号逻辑的知识表示与推理领域和基于统计的机器学习领域都有研究。特别在知识表示与推理领域,遗忘扮演着非常重要的角色。在命题逻辑、一阶谓词逻辑、模态逻辑、描述逻辑、回答集逻辑程序设计,以及情景演算等逻辑语言中都有大量的研究。模态逻辑适用于智能体的知识表示与推理。在模态逻辑中,知识遗忘首先在单智能体场景中被提出。随着多智能体系统研究的发展,多智能体模态逻辑中知识遗忘的研究也开始被关注。到目前为止,多智能体模态逻辑系统中的知识遗忘还无法有效计算。本文在多智能体模态逻辑系统K_n中对知识遗忘进一步展开研究。采用知识编译的思想,提出一种新的多智能体模态逻辑范式K_n-DNF。基于K_n-DNF,我们给出K_n中计算知识遗忘的有效算法,其时间复杂度是K_n-DNF公式长度的多项式时间。

乳腺X线和超声对乳腺结构扭曲征象诊断效能对比分析

目的:探讨乳腺X线摄影、超声对于结构扭曲征象的诊断价值。方法:选择我院2015年1月—2018年8月在乳腺X线摄影中发现结构扭曲(AD),并在1月内行术前乳腺超声检查,且有病理结果的276例患者进行回顾性分析。以病理结果为金标准,分析乳腺X线摄影、超声对于结构扭曲征象的诊断效能,P<0.05为差异有统计学意义。结果:276例病例中,179例恶性,97例良性。乳腺X线摄影联合超声与单独乳腺X线摄影、超声相比可以提高诊断的敏感度、假阳性率,减低特异性、假阴性率。乳腺X线摄影对星芒状AD、边缘回缩状AD、鱼骨刺状AD、单纯的AD及AD伴其他征象的ROC曲线下面积分别为0.620、0.677、0.721、0.643、0.618,乳腺X线联合超声诊断AD的ROC曲线下面积分别为0.630、0.689、0.712、0.699、0.606,无统计学意义(P>0.05),乳腺X线联合超声对其诊断效能无明显提高。结论:乳腺X线联合超声可以提高乳腺AD征象的诊断效能,但不能提高对AD三种影像表现形态及AD伴其他征象的诊断效能。

基于变论域模糊PID的航空转台控制系统研究

航空转台是进行地面仿真的关键设备,其控制系统的随动性对地面仿真结果有很大影响。围绕航空转台的控制结构和算法策略,提出使用粒子群优化算法迭代寻优以保证论域最佳的变论域模糊比例积分微分(proportion integral differential, PID)控制策略。以MATLAB作为仿真环境,分析本文所提算法策略的优化效果,仿真结果表明该控制策略相较于常规PID的时间乘绝对误差积分准则(ITAE)指标有显著提升。搭建以可编程多轴运动控制卡(programmable multi-axes controller, PMAC)控制器为核心的航空转台实物测试系统进行算法验证,实验结果表明,基于变论域模糊PID的航空转台控制系统可使航空转台的控制精度得以显著提升,超调量更小,调节时间更短,同时具备实用性,极大地提高了航空转台控制系统的随动性。

经尿道激光与电切术治疗非肌层浸润性膀胱癌效果及安全性比较的Meta分析

目的对比分析经尿道激光与经尿道电切手术对非肌层浸润性膀胱尿路上皮癌(non-muscle invasive bladder cancer, NMIBC)的疗效及安全性。方法在PubMed、Cochrane图书馆、Medline、Embase、Web of science、社会科学引文索引、中国期刊网全文数据库(CNKI)、中国生物医学文献数据库、维普医学数据库、万方数据库中,检索NMIBC使用经尿道激光与经尿道电切手术治疗的随机对照研究、半随机对照研究(队列研究和病例对照研究)文献,并使用RevMan 5.3软件对数据进行荟萃分析。结果共纳入16篇文献,病例2 570例。对比结果如下:手术时间(MD=-0.70;95%CI:-2.78~1.38;P=0.51)及术后尿道狭窄发生率(OR=0.70;95%CI:0.24~2.06;P=0.52)差异无统计学意义;术中闭孔神经反射(OR=0.05;95%CI:0.02~0.10;P<0.001)、膀胱穿孔发生率(OR=0.11;95%CI:0.04~0.29;P<0.001)、术后导尿时间(MD=-1.08;95%CI:-1.46^-0.71;P<0.001)、住院时间(MD=-1.00;95%CI:-1.66^-0.34;P=0.003)、膀胱冲洗(OR=0.21;95%CI:0.13~0.35;P<0.001)、12个月复发率(OR=0.67;95%CI:0.48~0.93;P=0.02)及24个月复发率(OR=0.60;95%CI:0.41~0.86;P=0.005)上激光优于电切。结论经尿道激光手术治疗NMIBC术中并发症(闭孔神经反射、膀胱穿孔)发生率、术后复发率低,恢复较快,较经尿道电切术具有一定优势。

数字乳腺X线与断层摄影对乳腺“结构扭曲”样病变的诊断效能分析

目的:探讨分析数字乳腺X线摄影与数字乳腺断层摄影(Digital breast tomosynthesis,DBT)对乳腺"结构扭曲"(AD)样病变的诊断效能。方法:采用回顾性研究方法,搜集选取2015年8月-2019年10月我院行数字乳腺X线摄影及DBT的女性患者,其主要影像学征象表现为AD,同时具有病理结果,并且除外具有外伤史、手术史及放化疗病史,共81例。运用SPSS 22.0统计软件对数据进行统计分析,以病理结果为"金标准",分析其灵敏度、特异度,采用配对χ2检验进行比较,认为P<0.05差异具有统计学意义。根据计算公式(灵敏度+特异度-1)计算约登指数。结果:以病理结果为"金标准",数字乳腺X线摄影、DBT对乳腺AD样病变诊断的灵敏度分别为68.2%、88.6%,根据配对卡方检验,P=0.049(P<0.05),二者差异具有统计学意义。联合诊断对乳腺AD样病变诊断的灵敏度为97.7%,与单独数字乳腺X线摄影(68.2%)比较,根据配对卡方检验,P=0.001(P<0.05),二者差异具有统计学意义;与单独DBT(88.6%)比较,根据配对卡方检验,P=0.219(P>0.05),二者差异无统计学意义。数字乳腺X线摄影、DBT对乳腺AD样病变诊断的特异度分别为67.6%、56.8%,根据配对卡方检验,P=0.388(P>0.05),二者差异无统计学意义。联合诊断对乳腺AD样病变诊断的特异度为32.8%,与单独数字乳腺X线摄影(67.6%)比较,根据配对卡方检验,P<0.001,二者差异具有统计学意义;与单独DBT(56.8%)比较,根据配对卡方检验,P=0.039(P<0.05),二者差异具有统计学意义。数字乳腺X线摄影、DBT及联合诊断的约登指数分别为35.8%、45.4%、32.8%。结论:DBT对乳腺AD样病变的诊断效能总体优于数字乳腺X线摄影。联合诊断与数字乳腺X线摄影相比也可以提高病灶的检出率,但与DBT无明显差异。

不同影像检查在乳腺结构扭曲中的研究进展

我国乳腺癌的发病率占女性恶性肿瘤疾病的首位,结构扭曲病变(architectural distortion,AD)作为触诊阴性乳腺癌的第三最常见影像学表现,也是乳腺癌最早出现的征象,具有重要的临床价值。AD具有较高的漏诊率及假阳性率。本文通过查阅文献,针对超声、乳腺X线摄影、乳腺数字三维断层摄影技术及核磁共振成像技术在乳腺结构扭曲病变中的研究进展及优缺点进行分析,进一步指导科学研究及临床工作。

基于负荷实测的内丘县配电网线损分析及降损措施研究

文中基于负荷实测开展对内丘县配电网节能降损措施的研究,通过对该县配电网线损率概况、线损率分电压等级占比情况、线损率分元件占比情况的分析,查找该县配电网当前存在的问题与造成线损的原因,提出节能降损措施方案并应用于配电网改造。

Calpain mediated cisplatin-induced ototoxicity in mice

Ototoxic drug-induced apoptosis of inner ear cells has been shown to be associated with calpain expression. Cisplatin has severe ototoxicity, and can induce cochlear cell apoptosis. This study assumed that cisplatin activated calpain expression in apoptotic cochlear cells. A mouse model of cisplatin-induced ototoxicity was established by intraperitoneal injection with cisplatin （2.5, 3.5, 4.5, 5.5 mg/kg）. Immunofluorescence staining, image analysis and western blotting were used to detect the expression of calpain 1 and calpain 2 in the mouse cochlea. At the same time, the auditory brainstem response was measured to observe the change in hearing. Results revealed that after intraperitoneal injection with cisplatin for 5 days, the auditory brainstem response threshold shifts increased in mice. Calpain 1 and calpain 2 expression significantly increased in outer hair cells, the spiral ganglion and stria vascularis. Calpain 2 protein expression markedly increased with an increased dose of cisplatin. Results suggested that calpain 1 and calpain 2 mediated cisplatin-induced ototoxicity in BALB/c mice. During this process, calpain 2 plays a leading role.

Lijiang 2.4-meter Telescope and its instruments

The Lijiang 2.4-meter Telescope(LJT), the largest common-purpose optical telescope in China,has been available to the worldwide astronomical community since 2008. It is located at the Gaomeigu site,Lijiang Observatory(LJO), in the southwest of China. The site has very good observational conditions.During its 10-year operation, several instruments have been equipped on the LJT. Astronomers can perform both photometric and spectral observations. The main scientific goals of LJT include recording photometric and spectral evolution of supernovae, reverberation mapping of active galactic nuclei, investigating the physical properties of binary stars and near-earth objects(comets and asteroids), and identification of exoplanets and all kinds of transients. Until now, the masses of 41 high accretion rate black holes have been measured, and more than 168 supernovae have been identified by the LJT. More than 190 papers related to the LJT have been published. In this paper, the general observation conditions of the Gaomeigu site is introduced at first. Then, the structure of the LJT is described in detail, including the optical, mechanical, motion and control system. The specification of all the instruments and some detailed parameters of the YFOSC is also presented. Finally, some important scientific results and future expectations are summarized.

Fundamental study and utilization on supercritical CO_(2) fracturing developing unconventional resources:Current status,challenge and future perspectives

Under the fact that considerable explo ration and production of unconventional re sources and wo rsening global climate,reducing carbon emission and rationally utilizing carbon resources have been drawn increasing attention.Supercritical CO_(2)(SC-CO_(2)) has been proposed as anhydrous fracturing fluid to develop unconventional reservoirs,since its advantages of reducing water consumption,reservoir contamination etc.Well understanding of SC-CO_(2)fracturing mechanism and key influencing factors will exert significant impact on the application of this technology in the field.In this paper,the fundamental studies on SC-CO_(2)fracturing from the aspects of laboratory experiment and simulation are reviewed.The fracturing experimental setups,fracture monitoring and characterizing methods,unconventional formation categories,numerical simulation approaches,fracturing mechanism and field application etc.,are analyzed.The fundamental study results indicate that compared with conventional hydraulic fracturing,SC-CO_(2)fracturing can reduce fracture initiation pressure and easily induce complex fracture networks with multiple branches.The field test further verifies the application prospect and the possibility of carbon storage.However,due to the limitation of reservoir complexity and attributes of SC-CO_(2),massive challenges will be encountered in SC-CO_(2)fracturing.According to the current research status,the limitations in basic research and field application are summarized,and the future development direction of this technology and relevant suggestions are proposed.

Astronomical Site Monitoring System at Lijiang Observatory

We installed two sets of Astronomical Site Monitoring Systems(ASMSs)at Lijiang Observatory(GMG),for the running of the 2.4-meter Lijiang optical telescope(LJT)and the 1.6-meter Multi-channel Photometric Survey Telescope(Mephisto).The Mephisto is under construction.The ASMS has been running on robotic mode since 2017.The core instruments:Cloud Sensor,All-Sky Camera and AutonomousDIMM that are developed by our group,together with the commercial Meteorological Station and Sky Quality Meter,are combined into the astronomical optical site monitoring system.The new Cloud Sensor's Cloud-Clear Relationship is presented for the first time,which is used to calculate the All-Sky cloud cover.We designed the Autonomous-DIMM located on a tower,with the same height as LJT.The seeing data have been observed for a full year.ASMS's data for the year 2019 are also analysed in detail,which are valuable to observers.