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71.
72.
Scope: Furan, a food contaminant formed during heat processing, induces hepatocellular tumors in rodents and high incidences of cholangiocarcinomas in rats even at the lowest dose (2 mg/kg b.w.) administered. Initial estimates suggested that human intake of furan may be as high as 3.5 μg/kg b.w./day, indicating a relatively narrow margin of exposure. The aim of this study was to establish dose–response data for cytotoxicity, regenerative cell proliferation and secondary oxidative DNA damage in livers of male F344 rats treated with furan at doses ≤2 mg/kg b.w. for 28 days. Methods and results: No significant signs of hepatotoxicity other than a mild, dose‐dependent increase in serum cholesterol and unconjugated bile acids, and no evidence of oxidative DNA damage were seen. Histopathological alterations and proliferative changes were restricted to subcapsular areas of the left and caudate liver lobes. Conclusion: Although statistically significant effects were only seen at the 2 mg/kg b.w. dose during the course of our study, a ~two and ~threefold increase in 5‐bromo‐2′‐deoxyuridine labeling index was observed at 0.1 and 0.5 mg/kg b.w., respectively, suggesting that chronic exposure to doses even below 2 mg/kg b.w. may cause proliferative changes in rat liver and highlighting the need to assess furan carcinogenicity at lower doses.  相似文献   
73.
Isotopically enriched 10boron for use in pillar-structured neutron detectors was successfully etched in an electron cyclotron resonance (ECR) plasma using SF6-based plasmas. The effects of radio frequency (RF) power, ECR power, gas flow rate, H2 and O2 incorporation into the plasma, and gas mixture ratios were examined. Etch rates up to approximately 1.35 μm/min were realized. In addition, etch morphology was examined, and the final shape of 10boron-coated pillars could be controlled through the etch gas mixture utilized. Selectivity to the underlying Si structure was apparent from scanning electron microscopy (SEM) micrographs of completed etches.  相似文献   
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X Chen  X Li  F Ding  W Xu  J Xiao  Y Cao  P Meduri  J Liu  GL Graff  JG Zhang 《Nano letters》2012,12(8):4124-4130
A cost-effective and scalable method is developed to prepare a core-shell structured Si/B(4)C composite with graphite coating with high efficiency, exceptional rate performance, and long-term stability. In this material, conductive B(4)C with a high Mohs hardness serves not only as micro/nano-millers in the ball-milling process to break down micron-sized Si but also as the conductive rigid skeleton to support the in situ formed sub-10 nm Si particles to alleviate the volume expansion during charge/discharge. The Si/B(4)C composite is coated with a few graphitic layers to further improve the conductivity and stability of the composite. The Si/B(4)C/graphite (SBG) composite anode shows excellent cyclability with a specific capacity of ~822 mAh·g(-1) (based on the weight of the entire electrode, including binder and conductive carbon) and ~94% capacity retention over 100 cycles at 0.3 C rate. This new structure has the potential to provide adequate storage capacity and stability for practical applications and a good opportunity for large-scale manufacturing using commercially available materials and technologies.  相似文献   
76.
Without clean power, petroleum and petrochemical equipment is subject to possible upset or catastrophic failure. To cost-effectively eliminate power disturbances due to lightning, fast ringing transients and electrical noise, the use of surge protection devices at building entrance feeders, key branch panels, critical loads and communication lines is recommended. Their use improves the operating reliability of electronic equipment  相似文献   
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Infection of Shiga toxin (Stx)-producing Escherichia coli induces hemolytic uremic syndrome (HUS) in 10 to 15% of cases in infants and young children. Although the endothelial cell damage induced by Stx is widely believed to be a primary event of renal dysfunction in HUS, the precise mechanism remains to be elucidated. We were able to examine the kidney obtained at autopsy of a child who died after HUS associated with Stx-producing Escherichia coli O157:H7 infection, and immunohistochemistry indicated the deposition of Stxl and Stx2 in a portion of the distal tubular epithelia. To our knowledge, this is the first report to show the presence of Stx in human tissue of a patient with HUS, and the results obtained in this study provide evidence that Stx indeed migrates into the kidney and binds to renal tubules during Stx-producing Escherichia coli infection.  相似文献   
79.
Titanium oxide (TiO2) thin films have been deposited on silicon, glass, and plastic substrates by destabilization of an aqueous titanium lactate solution at low temperatures (<100°C). The process uses a commercially available, low-cost precursor and is simple to perform; it involves only control of pH in aqueous, chelated titanium solutions. With this solution technique, high deposition rates (>50 nm/min), film thickness (>100 nm), and excellent film uniformity have been obtained. Uniform coatings can be applied on complex-shaped polymeric substrates and porous membranes. Films can be formed on both sulfonated and untreated polymeric surfaces. As-deposited films on plastic substrates consist of amorphous, hydrated TiO2. On sulfonated self-assembled monolayers on silicon substrates, nanocrystalline TiO2 films have been formed. The deposited films exhibit strong ultraviolet (UV) absorption with excellent transmission in the visible wavelength range, which indicates that the coatings may be useful as protective UV blockers for polymeric materials.  相似文献   
80.
We studied seizures that occur during the acute phase of aseptic and bacterial meningitis in childhood. Of the 108 children with aseptic meningitis, five had seizures (4.7%). Four patients developed them within 24 hours of the onset of the initial symptom (fever in 3 cases), and three had repeated seizures on the first day. One case had SIADH complication, but another neurologic abnormalities were not observed. On the 18 children with bacterial meningitis, three cases (16.7%) had seizure, which occurred on the second day of illness. Disturbance of consciousness and cerebral hypertension were observed in 2 cases each, and abnormal cerebral CT findings in all the three. The NSE level in the cerebrospinal fluid was elevated in 2 cases. Thus, seizures occurring in the acute phase of aseptic meningitis may reflect transient cerebral functional abnormality accompanying fever or SIADH, whereas those in bacterial meningitis may result from neural tissue damage due to encephalopathy or angitis. In aseptic and bacterial meningitis, the presence of seizures in the acute phase was not correlated with the neurological outcome.  相似文献   
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