钙预适应对膨胀离体大鼠心室所致心律失常的影响

为了证实钙预适应对膨胀离体大鼠心室所诱发的心律失常具有抑制作用 ,采用Langendorff方法灌流离体大鼠心脏。用正常灌流液灌流平衡后 ,离体心被随机分为 4组 :牵张对照组 ,钙预适应组 ,钙预适应 +维拉帕米组和钙预适应 +格列本脲组。维拉帕米和格列本脲在灌流液中的浓度分别为 1μmol/L和 10 μmol/L ,对钙预适应进行干预后及时用正常灌流液将他们从离体心洗脱。将可充灌液体的乳胶球囊通过左房及二尖瓣置于左室 ,通过向乳胶球囊注射液体对左室进行膨胀 ,记录膨胀前和膨胀过程中左室心电图和左室压力、冠脉流量和心率 ,观察心电图ST段和T波的变化 ,并计算对照组和各实验组由膨胀诱发心律失常的发生率和持续时间。结果 :通过乳胶球囊膨胀左室 ,使左室舒张末压增加相同的情况下 ,对照组心律失常总发生率达 10 0 % ,持续时间为 2 .5 6± 0 .4 6s ;钙预适应组较对照组心律失常总发生率明显降低 (40 % ) ,持续时间缩短到 1.6 7± 0 .6 1s(P均 <0 .0 5 ) ;用维拉帕米对钙预适应进行干预后 ,心律失常总发生率较钙预适应组增高 (90 % ) ,持续时间延长 (2 .5 0± 0 .4 6s) ;钙预适应 +格列本脲组心律失常发生情况和钙预适应组相似。各组离体心在膨胀前后冠脉流量和心率、心电图ST段和T波均未见明显变化。结论 :?     

Multi-Parameter Characteristics of Electric Arc Furnace Melting

The article presents the results of analyses of numerical modelling of selected factors in electric arc furnace melts. The aim of the study was to optimise the melting process in an electric arc furnace using statistical-thermodynamic modelling based on, among other things, multiple linear regression (MLR). The article presents tools and methods which make it possible to identify the most significant indicators of the process carried out on the analysed unit from the point of view of improvement. The article presents the characteristics of the process and creation of the MLR model and, by applying its numerical analyses and results of calculations and simulations for selected variables and indicator, identifying the operation of a selected furnace. Developed model to demand of electric energy identification was used for calculations of energy balances, the distribution of the energy used in the furnace was presented.     

Direct measurement of the viscoelectric effect in water

The viscoelectric effect concerns the increase in viscosity of a polar liquid in an electric field due to its interaction with the dipolar molecules and was first determined for polar organic liquids more than 80 y ago. For the case of water, however, the most common polar liquid, direct measurement of the viscoelectric effect is challenging and has not to date been carried out, despite its importance in a wide range of electrokinetic and flow effects. In consequence, estimates of its magnitude for water vary by more than three orders of magnitude. Here, we measure the viscoelectric effect in water directly using a surface force balance by measuring the dynamic approach of two molecularly smooth surfaces with a controlled, uniform electric field between them across highly purified water. As the water is squeezed out of the gap between the approaching surfaces, viscous damping dominates the approach dynamics; this is modulated by the viscoelectric effect under the uniform transverse electric field across the water, enabling its magnitude to be directly determined as a function of the field. We measured a value for this magnitude, which differs by one and by two orders of magnitude, respectively, from its highest and lowest previously estimated values.

The viscoelectric effect concerns the change in the viscosity of polar liquids in the presence of an electric field (1–3). It arises from the interaction of the field with the dipolar molecules, and while its molecular origins are still not well understood (4–6), it has considerable relevance in areas ranging from surface potential measurements (7–9) and boundary lubrication (10) to nanofluidics and its applications (11–13). Knowing the magnitude of the viscoelectric effect is thus of clear importance. It was first measured by Andrade and Dodd (1–3) for a range of polar organic liquids, by monitoring their flow in a narrow channel between metal electrodes across which a known electric field E was applied, and quantified via a viscoelectric coefficient f using an empirical relation based on their results:η(E)= η0(1 + f∣E∣2),[1]a simplified analysis leading to such a relation is given in Ref. (8). Here, η₀ is the unperturbed bulk liquid viscosity (i.e., in the absence of any field). For the case of water, however, the most ubiquitous and important polar liquid, measurement of its viscosity in the presence of a strong, uniform field presents a strong challenge (as discussed later in this section), and to our knowledge no such direct measurements have been reported. Over the past six decades, therefore, the magnitude of the viscoelectric effect in water has been only indirectly estimated by extrapolation from its values for organic liquids (8), from estimates of its effect on electrokinetic phenomena (11, 14–19), or by other approaches (7, 12, 20, 21). These estimated values, as expressed in the viscoelectric coefficient f, vary over more than three orders of magnitude, ranging from f ∼10⁻¹⁷–2.5 × 10⁻¹⁴ (V/m)² (SI Appendix, Section 7). For completeness, we note that results contradictory to the viscoelectric model have also been reported (22) (i.e., suggesting a decreased water viscosity in an electric field). The reasons for the large span of these estimated f values were attributed to various factors such as solid/liquid coupling, varying ionic sizes, and varying water permittivity (12, 19); however, while these factors may play some role, there is no evidence that they could lead to such large discrepancies.We believe, rather, that the origin of the large variance in the estimated magnitude of the viscoelectric effect arises because none of the experimental studies on water to date in which the f values were estimated was direct, in the sense of probing how the water viscosity varied with field in a uniform electric field. In all cases, viscosity changes were assumed to occur only in the nonuniform, rapidly decaying electrostatic potential near charged surfaces immersed in water. Changes in electrophoretic mobility, electro-osmosis, or hydrodynamic dissipation or water mobility between similarly charged solid surfaces were then attributed to some mean viscosity increase in these thin surface-adjacent layers (7, 11, 12, 14–21). In practice, however, the effect on these electrokinetic phenomena of viscosity or water mobility changes in the thin layers where such nonuniform, rapidly decaying fields are present is not easy to quantify reliably, especially in the presence of salt ions (12). At the same time, measuring the viscosity of water in a uniform electric field between two surfaces at different potentials, as was done for the polar organic solvents (2, 3) and which would provide a direct determination of its viscoelectric effect, presents a considerable difficulty. This is due to two main factors and arises because, in contrast to organic solvents, water may self-dissociate. Firstly, the potential difference that may be applied between the surfaces across water is limited, if electrolysis is to be avoided (23, 24), and secondly, electrostatic screening implies that the field decays strongly (within a Debye screening length) away from the surfaces (25–27). Even in purified water with no added salt (as in the present study), the potential decays rapidly away from a charged surface (see, e.g., Fig. 1C), so that to measure viscosity in a uniform field between two surfaces, one would require flow channels of width of order some tens of nanometers or less, presenting a major challenge.Open in a separate windowFig. 1.Numerical solution to the nonlinearized PB equation with σ_mica = −8.1 mC/m², ψ_gold = 0.07 V, and ion concentration c_b = 8 × 10⁻⁵ M, corresponding to the conditions of Fig. 4A. (A) Surface potential on the mica surface and surface charge on the gold surface as a function of separation D. (B) Average electric field approximated as (|ψ_gold − ψ_mica|/D). (C) Local potential ψ as a function of distance d from the mica surface for different separations D. Dashed line in larger-scale inset is an eye guide of a linear approximation.In the present study, we overcome this by directly probing the viscosity of purified water across which a uniform electric field acts while it is confined between two surfaces in a surface force balance (SFB). In our experiments, a molecularly smooth gold surface at a controlled (positive) surface potential approaches an atomically smooth mica surface at constant surface (negative) charge density, so that a known electric field acts across the water-filled gap of width D between them; moreover, this field is very close to uniform at the most relevant surface separations (D ≲ 30 nm, Fig. 1C). The dynamics of approach is strongly modulated by the viscous damping due to squeeze-out of the water as D decreases, and hence by its viscosity in the uniform electric field; by monitoring the approach rate of the surfaces at high temporal (millisecond) and spatial (approximately angstrom) resolutions, we are able therefore to directly evaluate the magnitude of the viscoelectric effect (the value of f).     

菊淀粉型巴戟天寡糖抗创伤后应激障碍行为学评价

目的 用大鼠和小鼠创伤后应激障碍(PTSD)模型评价菊淀粉型巴戟天寡糖(IOMO)对场景恐惧行为和焦虑行为的影响.方法 建立大鼠单次延长应激(SPS)模型和小鼠不可逃避足底电击(FS)模型,实验分组均为正常对照组、模型组、模型+舍曲林(Ser)组和模型+不同剂量IOMO组.在大鼠SPS模型中,于造模后每天1次ig给予I...     

腹腔镜手术使用超声刀对手术室二氧化碳浓度影响研究

将行经腹腔镜胆囊切除术患者80例,随机分为超声刀组(A组),高频电刀组(B组)。分别于手术开始前15min、手术开始后15 min、手术开始后30 min监测手术室内CO2浓度。与手术开始前15 min比较,两组手术室内CO2浓度均升高(P0.05);手术开始后15 min及30 min,A组室内CO2浓度较B组低(P0.05)。腹腔镜手术中使用超声刀可明显降低手术室内CO2浓度。     

The Gallbladder of the Electric Ray Torpedo Marmorata Risso Displays Excrescent Cholecystocytes with Merocrine and Apocrine‐Like Secretions

The gallbladder of Torpedo marmorata exhibits a mucosal surface layer of simple columnar epithelium with very tall cholecystocytes. The apical domain of each cell has few microvilli, but many mucous vesicles that are secreted by exocytosis at the cell apices. The apical regions may also elongate and undergo self‐excision while shedding mucus and cell debris into the gallbladder lumen in a manner similar to that described in mammals as a result of sex steroid treatment to induce gallstones and to that found in the cholecystitis associated with cholelithiasis. Numerous small mitochondria, spherical to elongated, are distributed throughout the cells, while the nuclei are often located in the lower third of each cell. In the lower part of the cholecystocytes, large and very densely contrasted lysosomes can be found. All cells are tightly joined by junctional complexes, including long, highly contrasted desmosomes. The fibromuscular layer is made of a loose stroma with a limited muscular component and a poor blood supply. Large diameter blood vessels can only be found in the subserosal layer. It is hypothesized that the obligatorily carnivorous diet of this ureotelic fish has resulted in the evolution of a gallbladder ultrastructure resembling that found in cholecystitis but without the associated cholelithiasis. Anat Rec, 2013. © 2012 Wiley Periodicals, Inc.     

强电脉冲治疗肿瘤提高抗癌药物疗效的研究

报道了用强电脉冲结合抗癌药物环磷酰胺作用于昆明小鼠S-180肉瘤。实验结果表明，电场 药物组的治疗效果最佳，与对照组相比，呈显著差异。同时观察到电场的作用可以抑制肿瘤的微血管形成，这样就减少了对癌细胞的营养供应、降低其新陈代谢，从而抑制了肿瘤的生长。     

常规康复治疗结合神经肌肉电刺激对脑卒中患者的疗效观察

目的:观察常规康复治疗结合神经肌肉电刺激治疗对脑卒中患者认知功能和日常生活活动能力的影响。方法:在常规康复治疗的基础上结合神经肌肉电刺激治疗对40例脑卒中患者进行治疗前后的比较,观察其疗效。运用简易精神状态评定量表(MMES)评定患者的认知功能,运用Barthel指数评定患者的日常生活活动(ADL)能力。结果:40例脑卒中患者经过8周的治疗,治疗前后相比,脑卒中患者MMES评定有显著性差异(P<0.05),Barthel指数评定治疗前后相比有非常显著性差异(P<0.01)。结论:常规康复治疗结合神经肌肉电刺激治疗对脑卒中患者的日常生活活动能力和认知能力的恢复具有一定促进作用,发病后的早期康复治疗比后期康复治疗效果更明显。     

水泵试验台液压夹紧装置设计

从系统机构设计、夹紧力分析、液压系统设计和电气控制原理等方面,阐述了水泵试验台液压夹紧装置的设计构造过程.为了保证试验时不发生泄漏现象,在管道联接端面采用抠槽密封处理技术,并对液压夹紧力进行计算与分析,得出在6.4 MPa的压力下,液压夹紧力约为88.238 kN,液压缸提供的最小工作压力为17.563 MPa.现场试验结果表明:与传统法兰联接方式相比,在规定试验压力下,该夹紧装置无泄漏现象,联接端面水力损失减小约0.156%,自动化程度高,水泵出厂检测台数增加约1.5倍,大幅度改善了水泵出厂检测的效率.