Stress-optical behaviour of trans-1,5-polypentenamer

The stress-optical behaviour of crosslinked trans-1,5-polypentenamer (TPR) in the unswollen and the swollen state was investigated and the results were compared with the data for other elastomers. The optical anisotropy of the statistical segment was found to be 5.6 × 10^?24 cm³ at 50°C. The number of chemical bonds in the main chain per statistical segment, a measure of the chain stiffness, was 5.6. From the comparison of the data in the unswollen and swollen state an estimate for the short range orientational order in the bulk polymer was made. The mean aggregate size of 1.6 at 50°C is relatively high compared to natural rubber.     

Numerical Study on Mould Powder Entrapment Caused by Vortexing in a Continuous Casting Process

Unsteady three‐dimensional turbulent flow phenomena are seen to have a major impact on steel quality in the continuous casting process. Usually steel mould powder is placed on top of the mould in order to use it as a lubricant between the solidifying steel and the mould and to prevent heat losses from the molten steel. It is well known that mould powder entrapment into the molten steel lowers the quality of the final steel products significantly. This can be caused by a vortexing flow at the interface between mould powder and molten steel near the submerged entry nozzle (SEN). The paper describes a study which was performed to analyse if commercial Computational Fluid Dynamics (CFD) software is capable of predicting the transient build‐up of vertical structures in the casting mould. Two‐phase‐flow phenomena have been modelled by using the Volume Of Fluid (VOF) method. The influence of different turbulence models, mesh densities and initial as well as boundary conditions on the resulting flow field was investigated. Due to the size and complexity of the problems the simulations partially had to be performed in parallel mode on a Linux‐cluster computing environment.     

Microstructural and micromechanical characterisation of TiAl alloys using atomic force microscopy and nanoindentation

Different microstructures were generated in the Ti–45Al–4.6Nb–0.2B–0.2C and Ti–45Al–1Cr alloys (at.%) by heat treatment. The microstructures were investigated using nanoindentation and atomic force microscopy which was compared with transmission electron microscopy. Topographic contrast is usually used for phase identification in the atomic force microscope. However, it was found that the topographic order of the phases changes with different microstructures and specimen preparations. Nanoindentation measurements provided local hardness values not obtainable by other methods and enabled clear distinction of the phases. The hardness values can give information on surrounding microstructure and solid solution hardening. The mean lamellar spacing of the colonies was measured using both atomic force microscopy and transmission electron microscopy. Atomic force microscopy was found to be suitable to determine the spacing between α₂/γ-interfaces offering the advantages of easier sample preparation and fewer specimens compared to evaluation by TEM analysis.     

Galvanic corrosion of polyacrylnitrile (PAN) and pitch based short carbon fibres in polyetheretherketone (PEEK) composites

When an electric current is conducted through a short fibre reinforced polyetheretherketone composite, being in contact with a stainless steel electrode, carbon fibre corrosion occurs. Surface analysis shows that structural defects range from debonding events and fibre cracking in the early stage of the corrosion process to the final disintegration of the fibre. The extent of fibre corrosion is quantified by atomic force microscopy, and the influence of fibre type, fibre volume content and the aqueous medium on the fibre corrosion is reported. Overall, polyacrylnitrile based fibres have a higher corrosion resistance than pitch based ones.     

Virtual Internet broadcasting

This article describes the design and first implementation of a virtual broadcast system whereby a multimedia content program can be edited, produced, and streamed from different locations. Data are stored and distributed decentrally, allowing multiple combinations of program objects to new programs. The virtual broadcast station is the network. This concept additionally offers the clients the opportunity to obtain an individual (personalized) program, still using bandwidth-economic multicast technologies. This is achieved by dividing multimedia streams into temporal chunks (chunk streams), streamed over different multicast host groups (distributed multicasting), using existing Internet session control protocols (SDP) and Internet transport protocols (RTP). A client application assembles the transmitted chunks to form an individual program. This technique can also be used to insert personal/local advertisements into broadcast-like services     

Increased Presence of Complement Factors and Mast Cells in Alveolar Bone and Tooth Resorption

Periodontitis is the inflammatory destruction of the tooth-surrounding and -supporting tissue, resulting at worst in tooth loss. Another locally aggressive disease of the oral cavity is tooth resorption (TR). This is associated with the destruction of the dental mineralized tissue. However, the underlying pathomechanisms remain unknown. The complement system, as well as mast cells (MCs), are known to be involved in osteoclastogenesis and bone loss. The complement factors C3 and C5 were previously identified as key players in periodontal disease. Therefore, we hypothesize that complement factors and MCs might play a role in alveolar bone and tooth resorption. To investigate this, we used the cat as a model because of the naturally occurring high prevalence of both these disorders in this species. Teeth, gingiva samples and serum were collected from domestic cats, which had an appointment for dental treatment under anesthesia, as well as from healthy cats. Histological analyses, immunohistochemical staining and the CH-50 and AH-50 assays revealed increased numbers of osteoclasts and MCs, as well as complement activity in cats with TR. Calcifications score in the gingiva was highest in animals that suffer from TR. This indicates that MCs and the complement system are involved in the destruction of the mineralized tissue in this condition.     

The TUM Accessibility Atlas: Visualizing Spatial and Socioeconomic Disparities in Accessibility to Support Regional Land-Use and Transport Planning

In recent years, the city of Munich has become more crowded due to its strong job market and its popularity as a tourist destination, resulting in a shortage of affordable housing and a strained transport network. It became evident that the city of Munich could not solve these problems alone, and would need close cooperation with neighboring municipalities that considered the various stakeholders. In 2007, this resulted in the formation of the Metropolitan Region of Munich, home to nearly six million people from 27 counties and 6 large cities, and includes 158 participating institutions. In 2009, the TUM Accessibility Atlas was developed for this newly formed region after numerous discussions with a variety of regional stakeholders who described their needs in assessing land-use and transport measures. The major task of this tool was to meet these needs and support this diverse region find a common regional identity.     

Household expenditure and tuberculosis prevalence in Viet Nam: prediction by a set of household indicators

目的:使用9项家庭特征,在越南全国结核病患病率调查过程研究结核病与家庭支出之间的关系.方法:为评估越南的结核病患病情况,于2006-2007年开展了全国分层整群抽样调查.在第二次越南生活水平调查中采用的9项家庭特征均以户为单位给予了评分.在越南生活水平调查数据库中,我们对这9项特征按人均家庭支出进行了回归分析；在我们的调查中,以系数来预测家庭支出水平(5分位级别),并评估其与结核病患病率的关系.结果:15岁以上人群的细菌学确诊结核病患病率为307/10万(95％可信区间为249～366).经过对干扰因素的调整,发现结核病患病率与家庭支出水平相关:五分位为最低家庭支出水平人群的患病率比五分位为最高家庭支出水平人群高2.5倍(95％可信区间为1.6～3.9).结论:通过9项家庭特征,我们能够非常准确地预测家庭支出水平.结核病患病率与估算的家庭支出水平之间存在显著相关性,提示在越南结核病与贫困相关.     

Allopurinol reduces bacterial translocation, intestinal mucosal lipid peroxidation, and neutrophil-derived myeloperoxidase activity in chronic portal hypertensive and common bile duct-ligated growing rats

The Chinese population in Hong Kong has a low incidence of invasive Haemophilus influenzae type b(Hib) disease, as well as carriage of the microorganism. Likely stimuli for the natural antibodies to Hib, which might protect against Hib infection, are cross-reactive antigens of bacteria like Escherichia coli K 100. Our aim was to determine the isotype and idiotype distribution and cross-reactivity of natural antibodies against Hib capsular polysaccharide (CP) in healthy Hong Kong Chinese. Titration of 20 sera by ELISA showed IgG antibodies reacting with Hib CP in all individuals. The antibodies were mainly IgG2, and their avidity index ranged widely. Isoelectric focusing (IEF) combined with immunoblotting showed patterns of IgG2 antibody clones against the CP of Hib and E. coli K 100 which were similar in 10 cases. Absorption with Hib CP only eliminated some bands in two sera. Absorption with K 100 CP did not remove any anti-Hib CP bands. In three sera additional clones of antibodies reacting to K 100 CP only, disappeared after absorption with this CP. Spectrotypic analyses of IgG antibodies reacting with anti-Hib idiotype 1 (Id-1) revealed stronger IEF patterns with bands in differing locations compared with anti-Hib CP antibodies. The strong reactivity of serum IgG, IgA and IgM antibodies with monoclonal anti-Hib Id-1 was confirmed by ELISA. This reactivity was not abolished after absorption of the sera with either Hib CP, or K 100 CP. The data indicate a high prevalence of Id-1 among Hong Kong Chinese. However, only one individual had Id-1 antibodies specific for Hib CP, judging from absorption experiments. Others had much lower activity of Id-1 anti-Hib CP antibodies compared with the total IgG Id-1, suggesting that Hong Kong subjects have Id-1-positive antibodies in their serum which are not specific for Hib CP. This is consistent with the nature of Id-1, which is a marker of A2VL region usage rather than a marker of a Hib CP paratope. We suggest that natural antibodies reacting with Hib CP in healthy Hong Kong Chinese are the product of exposure to some cross-reactive antigen(s), different from both Hib and E. coli K 100 CP.