The degradation and local tissue effects of collagen hydrogel and sponge implants in muscle

Collagen products will degrade and evoke certain local tissue reaction after being implanted. ISO 10993.6 is the international standard to evaluate local tissue reaction for biomaterials. However, even in the present version, it does not define the specific view fields for scoring local tissue reaction in the sections, which may influence the fair evaluation for the degradable polymer, such as collagen. In this study, 4 kinds of collagens and 2 kinds of bio-inert products were implanted into the rabbit muscle for 26 weeks, and two different scoring methods (uniform distribution scoring method and area locating scoring method) were applied to evaluate the local tissue reaction for each implant. The results showed that the tissue reaction on the interface was active, but the various scores in the implant and surrounding areas could help us to understand the differences of the degradation process. An area locating scoring method which selected the fields in the implant, interface and surroundings respectively showed a higher total score and offered more detailed information compared to the uniform distribution scoring method. Since the degradation and tissue reaction degree in the different areas are ever changing for the degradable implants, this area locating scoring method is sensitive, effective and applicable for the semi-quantitative evaluating system of ISO 10993.6.     

How instrument manufactures help with accreditation and ISO certification

 To help users of laboratory instrumentation to obtain laboratory accreditation and International Organization of Standardization certification, instrument manufactures should develop a comprehensive compliance programme for their products that includes product features, documentation and services for equipment validation and qualification. Received: 5 October 1998 · Accepted: 20 October 1998     

实施ISO9000标准,提高企业竞争力

ISO9000标准是一种国际认可的质量管理制度。文中通过对企业实施ISO9000标准的调查分析,阐明了ISO9000标准对提高企业管理水平的作用,对企业实施ISO9000标准过程中存在的问题进行深入剖析并提出解决办法和思路,强调持续改进的主导思想,将有助于企业不断提高业绩,增强市场竞争能力。     

A Note on the Multivariate Normal Hazard

The ISO* property of noncentrality parameters is derived for the expected value of an ISO* function of independent nonnegative two-parameter compound Poisson random variables and is then applied to unbiasedness of tests and monotonicity of power functions of tests in an order-restricted hypothesis testing problem for the noncentrality parameter. The ISO* property and the Schur convexity are also studied for a class of two-parameter distributions which has the additive property (i.e., is closed under convolution) and contains the one-parameter family with the semigroup property as a special case.     

ISO/REMCO近期活动

介绍ISO/REMCO 2007年已开展的和2008年将要开展的工作.重点介绍ISO/REMCO与标准物质相关的文件制定等一系列工作.     

水中氟化物国际标准检验方法的验证及其比较

介绍水中氟化物国际标准检验方法的验证结果,其中包括了干扰实验、标准曲线、准确度、精密度、检出限等.并将本方法测定结果与国标同类方法进行了比较.结果表明,该方法抗干扰性好,测量精度高,其标准曲线范围宽,点数设计合理,优于国标中的同类方法.应加以采纳和推广.     

A Low-Temperature Approach for the Phase-Pure Synthesis of MIL-140 Structured Metal–Organic Frameworks

In a systematic investigation, the synthesis of metal–organic frameworks (MOFs) with MIL-140 structure was studied. The precursors of this family of MOFs are the same as for the formation of the well-known UiO-type MOFs although the synthesis temperature for MIL-140 is significantly higher. This study is focused on the formation of Zr-based MIL-140 MOFs with terephthalic acid (H₂bdc), biphenyl-4,4′-dicarboxylic acid (H₂bpdc), and 4,4′-stilbenedicarboxylic acid (H₂sdc) and the introduction of synthesis field diagrams to discover parameters for phase-pure products. In this context, a MIL-140 network with H₂sdc as linker molecule is first reported. Additionally, an important aspect is the reduction of the synthesis temperature to make MIL-140 MOFs more accessible even though linkers with a more delicate nature are used. The solvothermal syntheses were conducted in highly concentrated reaction mixtures whereby a targeted synthesis to yield the MIL-140 phase is possible. Furthermore, the effect of the often-used modulator approach is examined for these systems. Finally, the characteristics of the synthesized MOFs are compared with physisorption measurements, thermogravimetric analyses, and scanning electron microscopy.     

Optimization of a Production Line of Porous (Aerated) Concrete

A process optimization of large-scale production plant for the manufacture of aereted concrete was realized by means of tracer techniques. The behaviour of all components which were labelled with short-lived radionclides such as ¹⁸F, ²¹Na, ⁴²K, ⁴³Sc and ¹¹⁰La were investigated both in a 3-chamber ball mill and in a wet mixer. The optimization of the, process led to new technological developments.     

Die Dynamik der festen Phase im Drehrohrofen

Mit Hilfe von Leitisotopen wurden in einem Drehrohrofen zur Keramsitherstellung die Durchlaufgeschwindigkeit des festen Phase und der axiale Mischungskoeffizient bestimmt. Zur Auswertung der experimentellen Daten wurde eine vereinfachte Methode zur Bestimmung der mittleren Verweilzeit des Einsatzes am Meβpunkt sowie der Varianz der Aktivitātskurven angewendet. Auf Grund der durchgeführten Untersuchungen konnte festgestellt werden, daβ die Durchlaufgeschwindigkeit des Einsatzes in Richtung der Ofenachse oszillierenden Schwankungen unterliegt, wobei der Feuchtigkeitsgehalt der festen Phase einen groβen Einfluβ auf die Durchlaufgeschwindigkeit hat. Der experimentall ermittelte axiale Mischungskoeffizient der festen Phase unterliegt ebenfalls Änderungen und erreicht den höchsten Wert in der Erwärmungszone.