Determination of fibrin and fibrinogen split products by their anticoagulant activity

A new diagnostic method to determine fibrinogen and fibrin splitting products is based on the fact that high-molecular fragments acting as specific inhibitors of fibrin self-assembly compose these products. Fibrinogen and fibrin splitting products are detected and determined quantitatively by prolongation of coagulation time in the test with the standard monomeric fibrin. The number of units of anticoagulating activity in the studied urine are the results of the determinations. Sensitivity of the method if necessary may be increased by adding of a certain amount of the fibrinogen and fibrin splitting products to the test that makes a favourable background for the action of the products. The method is rather sensitive, reliable and simple. It may be used in ordinary clinical laboratories. The method proved to be quite satisfactory when testing renal diseases at the clinic. It is of great significance for early detection of the transplanted kidney rejection. The new method is compared with the known immunological method which consist in determination of the inhibitory effect of the fibrinogen and fibrin splitting products on agglutination of erythrocytes of specific antibodies; the erythrocytes being subjected to "tanning" and "loading" with fibrinogen. A satisfactory correlation is found between the results of two methods.     

Stability analysis of PWM feedback control systems with PID regulators

Stability analysis is of great significance in those feedback control systems in which the power amplifier is operated as a pulse-modulator device, since under these circumstances the whole control system is highly non-linear. Stability in PWM feedback control systems with a proportional type regulator has been amply described in the literature. Only recently, however, have such studies been extended to include systems with a proportional-plus-integral regulator. In this paper the problem is considered for the case involving a PWM control system, where the regulator is a proportional-plus-integral-plus-derivative, the PWM modulator is of a very general type and the controlled process is of arbitrary order. The stability of the system is analysed by means of a discrete version of the second Lyapunov method ; this method in turn leads to an investigation of the positivity region of a quadratic form defined in the parameter space of the regulator. To improve the stability region obtained, a procedure is investigated whereby only a few parameters of the quadratic Lyapunov function need to be varied. The method proposed has proved extremely simple and flexible to apply, even in cases where the system is of arbitrary order.     

APPLICATION OF A PERTURBATION THEORY FOR EVALUATION ALGORITHMS FOR IDENTIFICATION OF A CONTINUOUS PLANT FROM DISCRETE DATA

Abstract

A perturbation theory for evaluation algorithms of arithmetic expressions is applied to the generalized least-squares identification of the continuous parameters by using nonperiodic discrete data. The sampling instants are distributed in such a way that a sequence of the elemental arithmetic expressions of the identification algorithm are suboptimized according to bang-bang rules on the extrema of appropriate variation intervals. The weighting scalars in the generalized least-squares method are updated with the same purpose.     

铅锌尾矿重金属释放影响因素的探讨

铅锌尾矿废渣若不经过处理,会通过风蚀、径流对环境造成重金属污染,对尾矿废渣污染的研究一直是大家关注的方向。多年来,pH被证实是影响重金属释放的重要因素。本文通过实验,研究了浸提方法、pH和盐度对铅锌尾矿废渣重金属元素释放的影响。结果表明,Pb、Zn、Cd、As在pH值呈酸性和碱性时浸出率都较高,Cu、Ni则在pH值为碱性时浸出率更高,盐度对Pb的释放影响效果更为明显。     

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

The aim of this work is to make progress towards the development of 3D reconstruction as a legitimate alternative to traditional 2D characterization of soot. Time constraints are the greatest opposition to its implementation, as currently reconstruction of a single soot particle takes around 5–6 h to complete. As such, the accuracy and detail gains are currently insufficient to challenge 2D characterization of a representative sample (e.g. 200 particles). This work is a consideration of the optimization of the steps included within the computational reconstruction and manual segmentation of soot particles. Our optimal process reduced the time required by over 70% in comparison to a typical procedure, whilst producing models with no appreciable decrease in quality.     

Stability of composite systems with an asymptotically hyperstable subsystem

In this note, it is proved that stability of composite systems including parallel subsystems can be achieved for certain sets of initial conditions and additional stability assumptions for the non-hyperstable subsystems. It is required that at least one subsystem be asymptotically hyperstable.     

关于定量界定设备修理周期若干问题的研究

本文通过对确定设备修理周期经验公式的讨论,指出了两点不足。对此笔者提出了:在生产过程中运用单位产品维修成本与产量的量化模型,从经济效益的角度动态界定最佳修理周期的设想,以期在设备维修管理方面,为企业提供最佳经济效益。并由此得出了几点有益的启示。     

Determinant spreading associated with demyelination in a nonhuman primate model of multiple sclerosis

Definition of the immune process that causes demyelination in multiple sclerosis is essential to determine the feasibility of Ag-directed immunotherapy. Using the nonhuman primate, Callithrix jacchus jacchus (common marmoset), we show that immunization with myelin basic protein and proteolipid protein determinants results in clinical disease with significant demyelination. Demyelination was associated with spreading to myelin oligodendrocyte glycoprotein (MOG) determinants that generated anti-MOG serum Abs and Ig deposition in central nervous system white matter lesions. These data associate intermolecular "determinant spreading" with clinical autoimmune disease in primates and raise important issues for the pathogenesis and treatment of multiple sclerosis.     

Hypotension following acute hypovolaemia depends on the caudal midline medulla

Acute hypovolaemia evokes abrupt, life-threatening hypotension and bradycardia. Hypotension can be evoked also by excitation of the caudal midline medulla (CMM). This study investigated the possible contribution of the CMM depressor area to hypotension evoked by acute hypovolaemia. Inactivation of the CMM, with either lignocaine or cobalt chloride did not alter resting arterial pressure. However lignocaine injections blocked the fall in arterial pressure, and cobalt chloride injections delayed the onset and significantly attenuated the size of hypovolaemic-evoked hypotension. These findings suggest that the CMM is a key region triggering hypotension after blood loss, and that the brain areas mediating cardiovascular response to challenges such as acute hypovolaemia are not the same areas that regulate resting arterial pressure.