Microstructural characteristics in Ni/zirconia bonding

Zirconia with various dopants of Y₂O₃ and CeO₂ was employed in the solid state bonding of an Ni/ceramic assembly. The interfacial microstructure of the bonding assembly was examined by electron microscopy and X-ray diffraction and the bonding strength was evaluated with a tensile test under constant pressure. An intermediate layer was observed in the interface of the 3Y₂O₃-10CeO₂-ZrO₂/Ni bonding assembly which revealed that the solid state bonding of Ni/zirconia required the formation of a thin oxide layer to wet the ceramics. In the Ni/zirconia bonding, the growth of NiO was influenced by the dopants in the zirconia. This would, in turn, result in different bonding strengths between ZrO₂ and nickel. The highest bonding strength occurred in the 12CeO₂-ZrO₂/Ni assembly.     

Does smoking protect from Alzheimer's disease? Alzheimer-type changes in 301 unselected brains from patients with known smoking history

The objective of this report is to investigate whether smoking exerts any influence on the number of senile plaques and Alzheimer neurofibrillary tangles. A retrospective study was based on unselected consecutive autopsy findings on the brains of 301 patients aged 65 years or older examined at the Institute of Pathology, Basel. Brains were investigated according to a fixed protocol. Histological examination was performed on 15 paraffin-embedded tissue blocks per brain using staining with silver impregnation specific for Alzheimer neurofibrillary tangles and for senile plaques, and Alzheimer-type changes were quantified. Retrospective assessment of smoking history was also based on a fixed protocol. Statistical analysis of the relationship between the smoking habits and the amount of Alzheimer-type changes was performed and included analysis of 72 age- and sex-matched smoker-nonsmoker pairs from within the total of 301 cases to compensate for variations in these changes due to age/sex alone. The influence of smoking on the total of 301 cases cannot be proven statistically. But a protective action against senile plaque formation could be demonstrated in 28 age matched pairs of smoking-nonsmoking women. Furthermore a positive correlation between the amount of smoking and the neurofibrillary changes as expressed in Braak stages in smokers of both sexes was present. Thus, there seems to be an influence of nicotine on the structural alterations of Alzheimer's disease which can exert itself in opposite directions.     

Hepatitis G virus infection in hemodialysis patients and the effects of interferon treatment

OBJECTIVE: To characterize the nature of hepatitis G virus (HGV) infections in hemodialysis patients and to determine the responsiveness of HGV to antiviral therapy in these patients. METHODS: HGV, a recently identified flavivirus, is associated with non-A-E viral hepatitis infections. We studied HGV infections in hepatitis C virus (HCV)-infected hemodialysis patients over a 1-yr period, using two independent PCR assays and nucleic acid sequencing. Thirty-four of 63 study patients were treated with interferon. RESULTS: We observed a 27% prevalence (17/63 patients) and a 4% annual incidence of HGV infections in the study population. HGV was not detected in any of the 10 HGV-infected patients immediately after interferon therapy. Although seven of these 10 patients developed HGV relapses, three had long-term responses. The interferon responsiveness of HGV and HCV appeared to be unrelated. In contrast, all seven untreated HGV-infected patients remained viremic. Sequence analyses of the different HGV isolates revealed only very limited genetic variability in the polymerase chain reaction-amplified regions of HGV during 1 yr of observation. CONCLUSIONS: Our data suggest that HCV-infected hemodialysis patients are at substantial risk of acquiring HGV infection and that HGV infections are prevalent in this population. In addition, HGV infections become chronic but are responsive to interferon treatment.     

Metallothionein and Fas (CD95) are expressed in squamous cell carcinoma of the tongue

Metallothionein (MT) is a chelator present in myoepithelial cells, whilst the Fas-receptor (APO-1, CD95) has been described primarily in human T Jurkat cells. 20 cases of carcinoma of the tongue were investigated immunocytochemically with regard to MT, Fas and Bcl-2. In normal oral squamous epithelium, MT is located in the basal/parabasal dividing cells only. In well-differentiated nests of carcinomas, MT is observed almost entirely in peripherally located cells. In situ end-labelling indicates apoptosis in the centre of these nests, but not in the peripheral areas. Less-differentiated areas show more general MT-positivity, but little apoptosis. All 24 tumours are Fas-positive, but normal epithelia are mainly negative (P < 0.0001). Bcl-2 protein was sparse in the tumours compared with MT and Fas (P < 0.0001). We thus suggest that MT, possibly due to its chelating properties, may contribute to delaying cells entering apoptosis, both in normal epithelium near the base and in less-differentiated regions of carcinoma. Moreover, Fas may be present in cells of human malignancies, as well as those of established malignant cell lines.     

Pattern and process of growth of the abnormal human fetus

Identifying patterns of fetal growth alteration benefits both the clinician and the researcher. Twenty-four measurements in three variable sets (anthropometric measures, organ weights, and long-bone measures from radiographs) were taken on fetuses both with and without pathological conditions that are suspected to result in growth alteration. In addition, radiographs of each case were examined for the presence or absence of ossification centers. Based on least-squares regressions of the normal group, we calculated standardized residuals for the affected group to identify patterns of growth alteration. A large sample of fetuses between 15 and 42 weeks of gestational age with a variety of pathological conditions is described and evaluated for growth alterations. Symmetric and asymmetric growth alteration was detected in a small part of the sample and was predominantly isolated to fetuses in the late third trimester. Although patterns of growth alteration have been suggested as a means for noninvasive diagnoses of syndromes (such as trisomy 21), no consistent patterns are discernible in the current group. The sample provides a unique opportunity to evaluate fetal growth in terms of the interaction between genetic and environmental influences.     

The influence of firing profile and additives on the PTCR effect and microstructure of BaTiO3 ceramics

Nonstoichiometric BaTiO₃ PTCR type materials are investigated with various amounts of MnO₂, Sb₂O₃ and MgO dopants. Specimens fired with a nonisothermal rate-controlled sintering profile exhibit a rather fine and uniform microstructure as compared to those processed by conventional sintering techniques. The temperature at which the resistivity anomaly begins is observed to decrease with Sb₂O₃ and MgO contents. The Curie point of BaTiO₃-based ceramics can be altered by addition of Sb₂O₃, and the dielectric peak is maintained by the presence of MgO additive. Magnesium ions act as acceptors in the BaTiO₂ lattice, while antimony ions as donors. The presence of magnesium compensates some of the antimony, hence the doped-BaTiO₃ seminonductive region is pushed to higher contents.     

Fabrication, thermal stability and microhardness of sputtered Ni–P–W coating

Ternary Ni–P–W alloy coating was fabricated by the RF magnetron sputtering technique with dual targets of electroless nickel alloy and tungsten metal. The composition of both the alloy deposited and the sputtered targets were evaluated by electron probe microanalysis. The homogeneity of Ni–P targets fabricated by electroless nickel plating on copper plates was revealed from cross-sectional line profile analysis. Transitions in microstructure, in terms of the tungsten content in the as-deposited alloy deposit, were discussed using X-ray diffraction analysis. Results of microhardness tests showed that the surface hardness could be engineered by controlling the composition and microstructure in the Ni–P–W coating. A relatively high microhardness of approximately 1900 HK was observed for the ternary coating with high tungsten contents of 65 wt.%. The thermal stability could be enhanced by addition of tungsten into the deposit compared to the binary Ni–P sputtered coating.     

Nano‐to‐Microdesign of Marimo‐Like Carbon Nanotubes Supported Frameworks via In‐spaced Polymerization for High Performance Silicon Lithium Ion Battery Anodes

Silicon (Si) has been perceived as a promising anode material for lithium‐ion batteries for decades due to its superior theoretical capacity, environmental benignity, and earth abundance. To accommodate the drastic volume expansion during lithiation, which is the primary drawback leading to poor cycling life, a novel structural design via fabricating the Marimo‐like carbon nanotubes frameworks with silicon nanoparticle (SiNP) filling in internal space has been developed. This facile fabrication procedure involves an in‐spaced polymerization process through ex situ polymerization, using pyrrole monomers with a soft organic template in which well‐dispersed SiNPs are present. Carbonization post‐treatment is then performed to construct rigid conductive networks. The thus‐fabricated 3D Marimo‐like hybrid structure exhibits a remarkably improved electrochemical performance compared with that of the simple ball‐milling method, which mainly originates from their structural advantages, including the built‐in buffer spaces and the robust line‐to‐line contact mode between the components. The state‐of‐the‐art structure exhibits an optimal high‐rate capability (422 mAh g^?1 at a current rate of 2 A g^?1) and long cycling stability (916 mAh g^?1 for 200th cycles at a current rate of 0.2 A g^?1) and achieves the requirements for industrial production with the facile and cost‐effective synthetic approach.     

Development of a multi-pathway probabilistic health risk assessment model for swimmers exposed to chloroform in indoor swimming pools

For swimmers, exposure to chloroform, a probable carcinogen, in indoor swimming pools can be through different pathways such as ingestion, dermal absorption, inhalation during swimming, and inhalation during resting. In order to evaluate health risk results from excessive exposure to chloroform, concentrations of chloroform in pool water were first collected and analyzed. Then, a two-layer model is used, which is capable of estimating the concentrations of chloroform in the boundary layer adjacent to the water surface and the concentrations of chloroform in indoor swimming pool air. The use of stratification model is important for estimating the risks for swimmers since they are exposed to these kinds of situations while performing swimming and resting in indoor swimming pools environment. The incremental lifetime cancer risk (ILCR) was then estimated using the multi-pathway exposure model. The results showed that the 95th percentile of ILCRs calculated for male and female swimmers were 2.80 × 10(-4) and 2.47 × 10(-4), respectively. The major exposure routes were found to be inhalation during swimming which contributes to more than 99% of the total health risk. Our study suggested that to protect swimmers from excessive exposure to chloroform, alternative methods or processes of disinfection should be considered for swimming pool managers.