浅谈再生污水地下回灌的健康危害风险

针对目前污水再生利用越来越广泛的现状,探讨了再生污水的健康危害风险评价方法,分析了非饮用回用及饮用回用时要注意的问题和对策。并对北京高碑店污水处理厂二级生化出水经深度处理地下回灌后用作饮用回用的健康危害风险进行了实例分析评价。     

Demographic aspects in indigenous communities of 3 regions of Colombia]

Venous compliance reflects the mechanical properties of the vein wall. Clinical methods of measurement have not been validated by comparison with the accepted in vitro measurement. Despite this, clinical assessment of vein compliance may have a series of useful applications: (1) to assess the progression of chronic venous insufficiency and the related hemodynamic forces acting on the saphenous vein wall; (2) to determine the suitability of the saphenous vein for replacement of an arterial conduit by testing its mechanical properties; and (3) to select the saphenous vein with preferable mechanical performance for coronary artery bypass. The aim of this study is to assess the relationship between in vitro and two in vivo methods of compliance measurement. Compliance of the saphenous vein was determined in 20 patients, using both an invasive and a noninvasive (A and B, respectively) method. Duplex scanning was used for diameter measurement. Venous pressure was derived either intravenously with a needle transducer, or noninvasively with limb length measurement. Patients underwent saphenous excision with further in vitro compliance measurement of the same vein segment (method C). The compliance values obtained with the three methods showed different degrees of correlation (r= 0.516, p = 0.0001 for method A versus method C; r = 0.658, p = 0.0001 for method B versus method C; r = 0.993, p = 0.0001 for method A versus method B). The relationships with the in vitro measurements that were determined validate both in vivo methods for assessment of saphenous vein compliance. Due to its completely noninvasive design, method B appears to have potential use for clinical assessment of saphenous vein wall properties.     

Drug clinics. How I treat a cutaneous ulcer in outpatients

A case of angiolymphoid hyperplasia with eosinophilia arising on the face of a woman is reported. Histologically, the uniqueness of this case is the presence of multinucleated cells (MNCs), besides the conventional dermal changes. Electron microscopy showed that some of the apparent MNCs are clusters of endothelial cells forming immature vascular lumens with numerous microvilli, and the other MNCs displayed the recognized features of fibrohistiocytic or myofibroblastic cells. Immunohistochemically, some MNCs were positive for Ulex europaeus agglutinin and Factor VIII-related antigen. From these findings, some of the MNCs are histologically endothelial sprouts, and the others are fibrohistiocytic cells in the present case.     

The relativity and geodiversity of medico-economic realities

The economic gestion of health care is difficult to handle. It covers several aspects which cannot pride to be accurate sciences. It strikes difficulties such as the geodiversity of problems to be solved and the nuances in the application of principles of social equity and medical ethics. The health-care analysis is also exposed to some politician interpretations biased by doctrinal a priori. Most often, a confrontation ensues between the political cenacle and the professionals directly involved in health-care.     

Highly branched melamine-phenolic novolaks

Summary A convenient synthesis of highly branched melamine-formaldehyde-phenolic oligomers, which can be applied as precursors for dendritic macromolecules, is described. The synthesis comprises the condensation of methylolated melamines with phenol in the presence of stoichiometric amounts of hydrochloric acid (similarly to the Mannich's reaction conditions). A mixture of hydroxyphenylmethylmelamines was obtained of an average content corresponding to the five substituted melamine ring. NMR and mass spectrometry (LSIMS/FAB) analysis showed the products to be almost free of neat melamine-formaldehyde and phenol-formaldehyde condensates. Received: 26 October 2001/Revised version: 8 March 2002/ Accepted: 25 March 2002     

Magnetic Specific Heat of Heavily p-Type Doped (Zn,Mn)Te:P

The magnetic contribution to the specific heat of bulk crystals of Zn_1?x Mn _x Te ( x = 0.03) heavily (up to 10¹⁹ cm^?3) p-type doped with P is studied over the temperature range 0.5–15 K and magnetic field range 0–3 T. The magnetic specific heat observed at zero magnetic field indicates that a substantial part of the magnetic ions has the degeneracy of their magnetic ground state lifted by d–d and p–d exchange interactions. The effect increases for doped and annealed samples with higher concentration of conducting holes. We have also carried out a theoretical analysis that takes into account the contributions due to small magnetic clusters, single magnetic ions in crystal field of distorted crystal lattice, and low energy excitations of the p–d exchange-coupled system of local moments and carriers.     

一种实用的电子线路参数优化算法

由于电子产品的设计周期越来越短，而对其降低成本和提高质量的要求却越来越高，电子线路的优化设计日益受到人们的关注。本文提出了一种实用的电子线路参数优化算法－均匀设计多项式拟合遗传优化算法。其主要思想是采用拟合的多元多项式代替电路仿真以指导遗传算法进行搜索，以便减少电路的仿真次数。并在数据采集过程中运用均匀设计方法，不仅能减少数据采样的数目，而且能使初始群体包含丰富的信息，更利于其收敛。电路优化实例表明，本算法对设计目标复杂以及参数较多电路的优化是有效的。