论非实验性因素对实验动物的影响

实验动物是生命科学研究和发展的重要支撑条件 ,在生命科学研究中影响动物实验结果的非实验性因素很多。本文探讨了物理、化学和微生物性因素对实验动物的影响 。

我国非实验性护理研究发展状况分析

目的:描述我国非实验性护理研究的发展状况。方法:该研究采用内容分析法,手工检索1990-2006年的《中华护理杂志》及《实用护理杂志》(于2003年更名为《中国实用护理杂志》)刊载的2547篇非实验性护理研究论文,进行全文逐篇分析。结果:我国非实验性护理研究论文数量不多,且以描述性研究为主;其占期刊载文量的比例较低,但随时间推进逐渐增加;研究的范围日益扩大,科学性日益增强,但在科研设计、资料收集及分析方面还存在着一些问题。结论:我国非实验性护理研究论文数量自20世纪90年代以来逐渐增加,但在研究的各个方面还存在不足,研究者的科研水平有待提高。

非实验性药物流行病学研究数据缺失的预防、检查和处理

与精心开展的随机化临床试验相比,非实验性研究中的缺失数据会对有效性形成更大的威胁。然而,非实验性真实世界研究可以更加准确地描述医疗干预措施在实际情境中对不同的患者群体的作用,从而补偿这些限制条件。如果研究者认识到缺失一定数量的数据(无论关于暴露、结局还是混杂因素)不可避免,就应该在研究开始时针对缺失数据制定计划,尽可能防止缺失数据,同时为处理重要变量的缺失数据制定规划。如不能获得所有患者的全部数据元素,就必须认真检查和处理缺失数据。可采用多重填补等统计技术填补空缺。这些方法都需要尽可能了解导致数据缺失的因素的相关假设及其与研究结果的关联。此文描述了预防缺失数据的策略和处理非实验性真实世界研究中缺失数据的分析方法,并加入了例证说明。

Mechanical heterogeneity characterization of coal materials based on nano-indentation experiments

To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experiments were conducted under both dynamic and static loading conditions,allowing us to gather the micro-mechanical parameters of coal for further analysis of its micro-mechanical heterogeneity using the box counting statistical method and the Weibull model.The research findings indicate that the load–displacement curves of the coal mass under the two different loading modes exhibit noticeable discreteness.This can be attributed to the stress concentration phenomenon caused by variations in the mechanical properties of the micro-units during the loading process of the coal mass.Consequently,there are significant fluctuations in the micro-mechanical parameters of the coal mass.Moreover,the mechanical heterogeneity of the coal at the nanoscale was confirmed based on the calculation results of the standard deviation coefficient and Weibull modulus of the coal body’s micromechanical parameters.These results reveal the influence of microstructural defects and minerals on the uniformity of the stress field distribution within the loaded coal body,as well as on the ductility characteristics of the micro-defect structure.Furthermore,there is a pronounced heterogeneity in the micromechanical parameters.Furthermore,we have established a relationship between the macro and micro elastic modulus of coal by applying the Mori-Tanaka homogenization method.This relationship holds great significance for revealing the micro-mechanical failure mechanism of coal.

药理研究中大环境因素对实验动物的影响分析

实验动物的生活体质及生理水平影响着实验动物自身的生长发育、生产繁殖及子孙后代的健康,也影响实验结果准确性的关键。本文通过探讨非实验性因素中大环境如温度、湿度、通风及气流等因素对实验动物居住的舒适度、体质健康、成长繁殖等影响,提示在实验动物饲养过程中大环境的重要性,尽量去避免非实验因素及人为因素的干扰,提高动物生活质量及体质,从而大大提升实验结果的准确性和可靠性。此外,还可为大因素应用于实验干预提供依据。

超声检测在非酒精性脂肪性肝病动物模型中的应用

目前非酒精性脂肪性肝病(NAFLD)在全球的高发病率不容忽视,其疾病谱涵盖广、早期不易被发现的特点对合适的诊断方法提出了迫切的需求。在临床上超声诊断NAFLD因其花费低、辐射小、依从性好等特点而被广泛应用。在动物模型的研究中,近年来也有多种超声检测方法可用于无创检测动物NAFLD的病变程度。本文从定性检测和半定量检测两个方面概述了不同超声检测方法检测动物NAFLD的原理,探讨了不同检测方法在NAFLD各阶段动物模型中的应用,以期在不同阶段NAFLD动物模型中选择最合适的超声诊断方法,从而提高动物模型病变程度和药物治疗效果评价的便捷性、准确性及可靠性。

Comparative study on three dynamic modulus of elasticity and static modulus of elasticity for Lodgepole pine lumber

The dynamic and static modulus of elasticity （MOE） between bluestained and non-bluestained lumber of Lodgepole pine were tested and analyzed by using three methods of Non-destructive testing （NDT）, Portable Ultrasonic Non-destructive Digital Indicating Testing （Pundit）, Metriguard and Fast Fourier Transform （FFT） and the normal bending method. Results showed that the dynamic and static MOE of bluestained wood were higher than those of non-bluestained wood. The significant differences in dynamic MOE and static MOE were found between bulestained and non-bluestained wood, of which, the difference in each of three dynamic MOE （Ep. the ultrasonic wave modulus of elasticity, Ems, the stress wave modulus of elasticity and El, the longitudinal wave modulus of elasticity） between bulestained and non-bluestained wood arrived at the 0.01 significance level, whereas that in the static MOE at the 0.05 significance level. The differences in MOE between bulestained and non-bluestained wood were induced by the variation between sapwood and heartwood and the different densities of bulestained and non-bluestained wood. The correlation between dynamic MOE and static MOE was statistically significant at the 0.01 significance level. Although the dynamic MOE values of Ep, Em, Er were significantly different, there exists a close relationship between them （arriving at the 0.01 correlation level）. Comparative analysis among the three techniques indicated that the accurateness of FFT was higher than that of Pundit and Metriguard. Effect of tree knots on MOE was also investigated. Result showed that the dynamic and static MOE gradually decreased with the increase of knot number, indicating that knot number had significant effect on MOE value.

Influence of the Pseudogap on the Inelastic Neutron Scattering Spectra of the Underdoped Lanthanum Cuprate

The influence of pseudogap on the inelastic neutron scattering spectra of the underdoped lanthanum cuprate is studied on the basis of the model which incorporates both the superconducting state and pseudogap state. It is found that the striking effects of the influence of the pseudogap on the incommensurability of the spin excitation spectrum are that in the superconducting state the pseudogap makes the intensity of the incommensurate peak increase, in the normal state the pseudogap not only makes the intensity of the incommensurate peak increase, but also sharpens the incommensurate peak and increases incommensurability.

Federal extended Kalman filter based on reconstructed observation in incomplete observations

In the estimation and identification of nonlinear system state,aiming at the adverse effect of observation missing randomly caused by detection probability of used sensor which is less than 1,a novel federal extended Kalman filter( FEKF) based on reconstructed observation in incomplete observations( ROIO) is proposed in this paper. On the basis of multi-sensor observation sets,the observation is exchanged at different times to construct a new observation set. Based on each observation set,an extended Kalman filter algorithm is used to estimate the state of the target,and then the federal filtering algorithm is used to solve the state estimation based on the multi-sensor observation data. The effect of the sensor probing probability on the filtering result and the effect of the number of sensors on the filtering result are obtained by the simulation experiment,respectively. The simulation results demonstrate effectiveness of the proposed algorithm.

Viscoelasto-plastic rheological experiment under circular increment step load and unload and nonlinear creep model of soft rocks

The viscoelastic-plastic creep experiments on soft ore-rock in Jinchuan Mine III were performed under circular increment step load and unload. The experimental data were analyzed according to instantaneous elastic strain, visco-elastic strain, instantaneous plastic strain and visco-plastic strain. The result shows that instantaneous deformation modulus tends to increase with the increase of creep stress; soft rocks enhance the ability to resist instantaneous elastic deformation and instantaneous plastic deformation during the multi-level of load and unload in the cyclic process. In respect of specimen JC1099, the ratio of visco-elastic strain to visco-plastic strain varies from 3.15 to 6.58, and the ratio has decreasing tendency with stress increase as a whole; creep deformation tends to be a steady state at low stress level; soft rocks creep usually embodies accelerated creep properties at high stress level. With the damaging variable and the hardening function introduced, a nonlinear creep model of soft rocks is established, in which the decay creep is described by the nonlinear hardening function H of viscidity coefficient. The model can describe the accelerated creep of soft rocks since the nonlinear damaging evolvement variable D of deformation parameter of rocks is introduced. Three stages of soft rocks creep can be described with the uniform creep equation in the nonlinear creep model. With this nonlinear creep model applied to the creep experiments of the ore-rock of Jinchuan Mine III, the nonlinear creep model＇s curves are in good agreement with experimental data.

Research on suppress vibration of rotor misalignment with shear viscous damper

A new type of shear viscous damper for rotating machinery is designed. The new damper with good stability and reliability can inhibit all kinds of frequency multiplication vibration caused by misalignment in the condition of nonstop machine. It analyzes and discusses the use of the shear viscous damper for misalignment vibration response inhibition with a finite element method, and experi ments are extensively carried out with a laboratory test rig. Both the simulation and experimental re suits basically agree well in that, the damper can effectively control the misalignment vibration of the rotor system and improves the stability of the plitude of one time running speed component bration has been basically eliminated. entire rotor system. Experimental results show the am decreases by 30% , and the two time running speed vibration has been basically eliminated.

A Fully Flexible Potential Model for Carbon Dioxide

A fully flexible potential model for carbon dioxide has been developed to predict the vapor-liquid coexistence properties using the NVT-Gibbs ensemble Monte Carlo technique(GEMC).The average absolute deviation between our simulation and the literature experimental data for saturated liquid and vapor densities is 0.3% and 2.0%,respectively.Compared with the experimental data,our calculated results of critical properties(7.39 MPa,304.04 K,and 0.4679 g?cm-3) are acceptable and are better than those from the rescaling the potential parameters of elementary physical model(EPM2).The agreement of our simulated densities of supercritical carbon dioxide with the experimental data is acceptable in a wide range of pressure and temperature.The radial distribution function estimated at the supercritical conditions suggests that the carbon dioxide is a nonlinear molecule with the C O bond length of 0.117 nm and the O C O bond angle of 176.4°,which are consistent with Car-Parrinello molecular-dynamics(CPMD),whereas the EPM2 model shows large deviation at supercritical state.The predicted self-diffusion coefficients are in agreement with the experiments.

Improving oil recovery in the CO2 flooding process by utilizing nonpolar chemical modifiers

By means of experiments of C02 miscibility with crude oil, four nonpolar chemicals were evaluated in order to enhance the miscibility of C02 with crude oil. Through pre-slug injection and joint injection of toluene in CO2, crude oil displacement experiments in the slim-tube were conducted to investigate effects of the toluene- enhanced C02 flooding under simulated subterranean reservoir conditions. Experimental results showed that toluene can enhance extraction of oil into C02 and dissolution of C02 into oil with the increment of 251% and 64% respectively. Addition of toluene can obviously improve the oil recovery in either pre-slug injection or joint injection, and the crude oil recovery increased with the increase of the toluene concentration. The oil recov- ery can increase by 22.5% in pre-slug injection with the high toluene concentration. Pre-slug injection was recom- mended because it can consume less toluene than joint injection. This work could be useful to development and application of the CO） flooding in the oil recoverv as well as CO2 emission reduction.

Upper bound solutions for supporting pressures of shallow tunnels with nonlinear failure criterion

Linear failure criterion is widely used in calculation of earth pressure acting on shallow tunnels. However, experimental evidence shows that nonlinear failure criterion is able to represent fairly well the failure of almost all types of rocks, A nonlinear Hock-Brown failure criterion is employed to estimate the supporting pressures of shallow tunnels in limit analysis framework. Two failure mechanisms are proposed for calculating the work rate of extemal force and the internal energy dissipation. A tangential line to the nonlinear failure criterion is used to formulate the supporting pressure problem as a nonlinear programming problem. The objective function formulated in this way is minimized with respect to the failure mechanism and the location of tangency point. In order to assess the validity, the supporting pressures for the proposed failure mechanisms are calculated and compared with each other, and the present results are compared with previously published solutions when the nonlinear criterion is reduced to linear criterion. The agreement supports the validity of the proposed failure mechanisms. An experiment is conducted to investigate the influences of the nonlinear criterion on collapse shape and supporting pressures of shallow tunnels.

Realization of Bipartite Positive-Operator-Value Measurements of Two-Photon Polarization States

In this letter, we propose a scheme of a special quantum optical Fredkin gate assisted by optical manip- ulations and postselection from the coincidence measurements, and then modify it with cross-Kerr nonlinearities to be suitable for the realization of all possible positive operator-valued measurements of bipartite polarization states. This scheme is feasible in the lab with the current experimental technology.

Polar Vortex Response to Pacific Ocean Warming and Its Additive Nonlinearity with the Indian Ocean

A previous modeling study about Pacific Ocean warming derived polar vortex response signals, by subtracting those in the Indian Ocean warming experiments from those in the Indo-Pacific. This approach questions the resemblance of such an indirectly derived response to one directly forced by Pacific Ocean warming. This is relevant to the additive nonlinearity of atmospheric responses to separated Indian and Pacific Ocean forcing. In the present study, an additional set of ensemble experiments are performed by prescribing isolated SST forcing in the tropical Pacific Ocean to address this issue. The results suggest a qualitative resemblance between responses in the derived and additional experiments. Thus, previous findings about the impact of Indian and Pacific Ocean wanning are robust. This study has important implications for future climate change projections, considering the non-unanimous warming rates in tropical oceans in the 21st century. Nevertheless, a comparison of present direct-forced experiments with previous indirect-forced experiments suggests a significant additive nonlinearity between the Indian and Pacific Ocean warmings. Further diagnosis suggests that the nonlinearity may originate from the thermodynamic processes over the tropics.

x_F(or y)-Dependence of Nuclecir Absorption and Energy Loss Effects on J/ψ Production

By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the J/ψ ＂normal nuclear absorption＂ and energy loss effects are studied in a GIauber formalism at HERA and RHIC energies. Assuming that the absorption cross section σabs increases with the charmonium-nucleon center of mass energy, the results reveal a significant dependence of the aabs on rapidity g at RHIC energies. The initial-state energy loss effect, which is found important only at HERA energies, is also considered, and its influence should be eliminated when we studied the absorption effect at low collision energies. Finally, we also present the theoretical prediction for LHC.

Verification of Seismic Performance of Pile Foundation in Composite Ground through Experimental and Numerical Methods

A new construction method of pile foundation in composite ground, in which, prior to installing piles, the ground is improved around the heads of the piles in soft ground or ground subject to liquefaction, which is introduced in this paper. This construction method uses a combination of pile foundation construction together with common ground improvement methods, including deep mixing, preloading and sand compaction piling, and it is referred to as the composite ground pile method. Since an artificial ground with relatively high rigidity comparing with that of the original ground was formed around the pile in this method, and the seismic performance has not been made clear, thus the seismic performance of piles in composite ground was systematically analyzed through a series of centrifuge model tests and numerical analyses by using dynamic nonlinear finite element method, and a verification method for the seismic performance of piles in composite ground was proposed on the basis of the experimental and numerical results.

Modified Equation of State for Pure Compounds

Proposed new cubic equation of state is more accurate than others in result and simple in form. The equation has been tried with 23 pure compounds including both polar and non-polar compounds. Experimental values of these compounds collected from various journals were compared with proposed model and found to be more accurate than other widely used cubic equations of state like SRK and Peng Robinson. The form of current EOS best suits to PVT data and total error is almost halved for a set of experimental data in the most cases.