肺炎克雷伯菌尿路感染167例碳青霉烯耐药风险列线图预测模型的构建

目的 构建肺炎克雷伯菌尿路感染碳青霉烯耐药风险列线图预测模型。方法 回顾性分析2018年1月至2020年12月在秦皇岛市第一医院确诊为肺炎克雷伯菌尿路感染的成人住院病人167例临床资料,将尿液标本中检出耐碳青霉烯类肺炎克雷伯菌(CRKP)的62例病人设为CRKP组,非CRKP的105例病人设为非CRKP组。采用logistic回归分析发生CRKP尿路感染的独立危险因素,并将167例病人按照分层随机抽样以7∶3比例分为训练集(118例)和验证集(49例),然后使用训练集根据独立危险因素建立CRKP尿路感染列线图风险预测模型。采用校准曲线和受试者操作特征曲线(ROC曲线)评估列线图预测模型的准确度和区分度。结果 CRKP组肺炎克雷伯菌对头孢呋辛、哌拉西林/他唑巴坦、美罗培南、阿米卡星耐药性分别为100%(62/62)、100%(62/62)、98.4%(61/62)、51.6%(32/62),明显高于非CRKP组的42.9%(45/105)、8.6%(9/105)、1.0%(1/105)、3.8%(4/105)。多因素logistic回归分析显示,入住重症监护室、两周内使用碳青霉烯和酶抑制剂为CRKP尿路感染的独立危险因素(OR=8.95、5.52、6.12,P<0.05)。训练集、验证集一致性指数(C-index)分别为0.88,0.90。ROC曲线下面积为0.88。校准曲线和ROC曲线提示模型准确度、区分度良好。结论 通过分析CRKP尿路感染的危险因素构建风险列线图预测模型,模型具有良好的准确度和区分度,可有效预测肺炎克雷伯菌尿路感染碳青霉烯耐药发生风险,并可依此实施更有针对性的防护措施和制定合理的药物治疗方案。

2018~2021年医院尿培养病原菌及菌株耐药性变迁

目的 分析秦皇岛市第一医院4年间尿培养病原菌分布情况及耐药菌株变迁情况,为尿路感染临床诊疗提供参考依据。方法 采用回顾性分析,以2018年1月~2021年12月期间收集的2 782株菌株为研究对象,菌株的鉴定和药敏试验采用Vitek2 Compact全自动微生物鉴定及药敏系统,用SPSS软件对数据进行分析。结果 2018~2019年共收集菌株1 179株,其中位于前3位的是大肠埃希菌420株(35.6%)、屎肠球菌167株(14.2%)、肺炎克雷伯菌126株(10.7%)。1 603株来自2020~2021年,大肠埃希菌(479株,29.9%)、肺炎克雷伯菌(282株,17.6%)和屎肠球菌(161株,10.0%)位于前3位。与2018~2019年相比,2020~2021年肺炎克雷伯菌的耐药率趋于稳定或有明显下降,但对第二代头孢菌素和氟喹诺酮类持续呈现较高的耐药率(>50%)。大肠埃希菌对大多数抗菌药物的耐药率呈明显下降趋势,但对环丙沙星和美罗培南的耐药率分别从73.8%、2.6%上升至76.6%、9.2%。屎肠球菌对喹诺酮类的耐药率持续高于95%,利奈唑胺耐药屎肠球菌检出率从1.8%显著增加至24.8%。结论 4年间该院尿路感染细菌谱和耐药性发生了变迁,应结合该院细菌耐药监测结果,合理使用抗菌药物。

医院念珠菌尿路感染菌株分布及耐药性分析

目的探讨医院念珠菌尿路感染的菌群分布及耐药性情况,为抗菌药物选择提供参考。方法回顾性分析2018年1月—2020年12月我院念珠菌泌尿系感染患者的中段尿培养阳性结果(菌株鉴定和药敏试验)及临床资料。结果212例患者中共分离出念珠菌256株,其中男性102例,女性110例,平均年龄为71.7±14.2岁。其中白念珠菌101株、热带念珠菌76株、光滑念珠菌31株占分离株的前3位,前3种念珠菌占总分离菌的81.2%。内科检出的菌株中以白念珠菌为主,菌株外科检出中以热带念珠菌为主,差异具有统计学意义(P<0.05)。所有菌株对两性霉素B和氟胞嘧啶敏感,非白念珠菌对唑类抗真菌药敏感性较差,其中近平滑念珠菌、热带念珠菌在外科及ICU的耐药问题更为严重,差异具有统计学意义(P<0.05)。结论我院念珠菌尿路感染内科、外科主要菌株不同,内科以白念珠菌为主,外科以热带念珠菌为主。热带念珠菌对唑类敏感性最低,且对氟康唑及伏立康唑的耐药性在外科病房和重症监护病房表现得更为严重。临床上内科经验性治疗可首选氟康唑,对于外科及重症患者建议应考虑首选两性霉素B和/或氟胞嘧啶进行治疗。

基于FPGA的控制算法定点化设计

运动控制算法在现场可编程逻辑门阵列(Field Programmable Gate Array,FPGA)上实现过程中,当数据类型由浮点转定点时,存在无法保证高精度的问题。为此使用simulink中的定点工具(Fixed-Point Tool)对算法内部各信号数据的范围进行分析,然后人为地对Fixed-Point Tool给出的建议位宽进行修正,从而使算法在保证较高精度的同时,也解决了采用统一较长位宽在FPGA上实现时造成的资源浪费问题。与传统的人为定义数据位宽相比,使用Fixed-Point Tool设置数据位宽,在输入数据范围发生变化时,能够更加灵活、动态地调整算法内部数据位宽。

232株热带念珠菌感染的临床特点及菌株耐药性分析

目的 研究与分析我院热带念珠菌的临床分布及耐药性特点等,为临床预防和治疗热带念珠菌感染提供参考依据。方法 回顾性分析2018年1月—2021年12月间秦皇岛市第一医院分离出热带念珠菌的患者的临床资料。结果 共收集到热带念珠菌232株,其标本来源主要为尿液标本(134株占57.8%),其中男性156例,女性76例,平均年龄为(68.5±16.5)岁。科室来源主要为ICU (102株)、呼吸内科(39株)、肾脏内科(14株),这前3位科室占热带念珠菌总株数的66.8%。药敏试验结果表明,分离出的热带念珠菌菌株对5-氟胞嘧啶和两性霉素B完全敏感,对氟康唑、伊曲康唑和伏立康唑的耐药率均较高,分别为41.3%、44.9%和42.7%,对伊曲康唑的敏感率最低为30.7%。且对伏立康唑的耐药性在外科病房和ICU表现得最为显著。从对临床常用抗生素耐药性变化趋势的统计发现,2018年—2020年热带念珠菌对氟康唑、伊曲康唑和伏立康唑的耐药率一直很高,2021年耐药率显著降低。结论 我院的热带念珠菌耐药现象从2021年开始有明显好转,这与医院加强临床科室对抗生素使用的管控密切相关,因此为减少或延缓耐药菌株的出现,防止耐药菌感染的爆发,应继续加强管控力度。

Active Damping of Milling Vibration Using Operational Amplifier Circuit

The problem of chatter vibration is associated with adverse consequences that often lead to tool impairment and poor surface finished in a workpiece, and thus, controlling or suppressing chatter vibrations is of great significance to improve machining quality. In this paper, a workpiece and an actuator dynamics are considered in modeling and controller design. A proportional-integral controller(PI) is presented to control and actively damp the chatter vibration of a workpiece in the milling process. The controller is chosen on the basis of its highly stable output and a smaller amount of steady-state error. The controller is realized using analog operational amplifier circuit. The work has contributed to planning a novel approach that addresses the problem of chatter vibration in spite of technical hitches in modeling and controller design. The method can also lead to considerable reduction in vibrations and can be beneficial in industries in term of cost reduction and energy saving. The application of this method is verified using active damping device actuator(ADD) in the milling of steel.

2812株肺炎克雷伯菌临床特点及耐药性比较

目的 了解秦皇岛市第一医院肺炎克雷伯菌的临床分布特点及耐药情况。方法 对2018年1月—2021年12月分离培养的肺炎克雷伯菌进行标本分布、科室分布及耐药性调查分析。结果 4年来共分离肺炎克雷伯菌2 812株,其中标本来源构成比居前3位为痰液、血液和尿液,分别占62.5%、12.3%和9.4%。分离株主要来源科室分别为ICU、呼吸科和神经外科。非碳青霉烯耐药肺炎克雷伯菌对临床常用的15种抗菌药物普遍敏感。碳青霉烯耐药肺炎克雷伯菌株对头孢菌素类、氟喹诺酮类、碳青霉烯类、青霉素复方制剂的耐药率均超过85%。除复方新诺明外,尿液标本比血液、痰液标本的耐药性更为严重。结论 肺炎克雷伯菌分布与抗菌药物使用相关,碳青霉烯耐药肺炎克雷伯菌的耐药现象比较严重。

Design of a tunable mass damper for mitigating vibrations in milling of cylindrical parts

Milling the free-end of cylindrical parts, which are vertically fixed on the machine table,often suffers from large chatter vibrations. This kind of phenomenon is harmful to the cutting process. Therefore, it is of great importance to develop means to suppress these undesirable chatters.This paper proposes a new idea for designing a tunable mass damper(TMD) to reduce vibrations in milling of cylindrical parts. Frequency response function(FRF) of the milling system is derived to comprehensively reveal the influence of both the dynamic response of the machine tools and the TMD. Critical axial depth of cut, which is usually used to characterize the process stability, is formulated by considering the FRFs of both the milling system itself and the TMD. Maximization of critical axial depth of cut is taken as objective function, while kernel dynamic parameters of TMD,which are involved in the derived expression of critical axial depth of cut, are extracted as designable variables. Optimization procedure is carried out to adjust the parameters of TMD by using sequential quadratic programming algorithm. A series of experiments with a designed passive TMD validate that the design has a good performance in reducing vibrations and improving stability of milling process.

Recent Advances in C_(2) Gases Separation and Purification by Metal-Organic Frameworks

Separation of C_(2) gases(C_(2)H_(2)/C_(2)H_(4),C_(2)H_(6)/C_(2)H_(4) and C_(2)H_(2)/CO_(2))mixtures is one of the most important and energy-demanding processes in chemical industry.Traditional separation methods(fine distillation separation and selective catalytic hydrogenation separation)have the shortages of high energy consumption and inefficient use of resources,affecting the achievement of peak carbon dioxide emissions and carbon neutrality targets.Separation based on adsorption is considered as one of the best ways to achieve low-energy separations.Therefore,it is of great importance to synthesize materials that enable the effective separation and purification of C_(2) gases under mild conditions.As an emerging class of porous materials,metal-organic frameworks(MOFs)show great promise in the field of gas separation and purification due to their ultra-high specific surface area,easily modifiable pore surfaces,structural designability and functionalization.Herein,we summarize recent research advances by use of MOFs sorbents for the separation and purification of C_(2) gases,including C_(2)H_(2)/C_(2)H_(4),C_(2)H_(6)/C_(2)H_(4) and C_(2)H_(2)/CO_(2).Relationship between structures and separation mechanism is also explored.Furthermore,challenges and possible research directions related to the further exploration are also discussed.

Determination of optimal geometrical parameters of peripheral mills to achieve good process stability

This paper focuses on optimization of the geo-metrical parameters of peripheral milling tools by takinginto account the dynamic effect. A substructure synthesistechnique is used to calculate the frequency responsefunction of the tool point, which is adopted to determinethe stability lobe diagram. Based on the Taguchi designmethod, simulations are first conducted for varying com-binations of tool overhang length, helix angle, and teethnumber. The optimal geometrical parameters of the tool aredetermined through an orthogonal analysis of the maxi-mum axial depth of cut, which is obtained from the pre-dicted stability lobe diagram. It was found that thesequence of every factor used to determine the optimal toolgeometrical parameters was the tool overhang length, teethnumber, and helix angle. Finally, a series of experimentswere carried out as a parameter study to determine theinfluence of the tool overhang length, helix angle, and teethnumber on the cutting stability of a mill. The same con-clusion as that obtained through the simulation wasobserved.

High-efficiency technique based on dielectrophoresis for assembling metal,semiconductor,and polymer nanorods

This paper presents a high-efficiency technique based on dielectrophoresis (DEP) for assembling metal, semiconductor, and polymer nanorods, which are synthesized by electrochemical deposition (ECD). The assembly patterns of these nanorods (width: 20 nm; length: 7 μm) were designed using a finite element method (FEM) simulation tool. Further, these nanorods were used in our experiment after their assembly patterns were fabricated. The assembly yield was found to be approximately 70% at an AC voltage of 30 Vp-p and at frequencies of 20 and 30 kHz, and the DC voltage prevented the random alignment of the nanorods at the edge of the assembly pattern. Moreover, the above-mentioned nanorods, which had different permittivities, were found to have similar assembly yields. The proposed method can be improved and applied to nanostructure device fabrication.