The Large Electrochemical Capacitance of Microporous Doped Carbon Obtained by Using a Zeolite Template

A novel microporous templated carbon material doped with nitrogen is synthesized by using a two‐step nanocasting process using acrylonitrile (AN) and propylene as precursors, and Na–Y zeolite as a scaffold. Liquid‐phase impregnation and in situ polymerization of the nitrogenated precursor inside the nanochannels of the inorganic scaffold, followed by gas‐phase impregnation with propylene, enables pore‐size control and functionality tuning of the resulting carbon material. The material thereby obtained has a narrow pore‐size distribution (PSD), within the micropore range, and a large amount of heteroatoms (i.e., oxygen and nitrogen). In addition, the carbon material inherits the ordered structure of the inorganic host. Such features simultaneously present in the carbon result in it being ideal for use as an electrode in a supercapacitor. Although presenting a moderately developed specific surface area (S_BET = 1680 m² g^–1), the templated carbon material displays a large gravimetric capacitance (340 F g^–1) in aqueous media because of the combined electrochemical activity of the heteroatoms and the accessible porosity. This material can operate at 1.2 V in an aqueous medium with good cycleability—‐beyond 10 000 cycles—and is extremely promising for use in the development of high‐energy‐density supercapacitors.     

Determining suitability of a fly ash for silica extraction and zeolite synthesis

Zeolitic material is obtained from fly ash both by direct conversion of the ash or from SiO₂ extracts obtained from fly ash. This study focuses on determining the suitability of a fly ash for SiO₂ extraction and for zeolite synthesis by direct conversion. The SiO₂ extraction experiments from different fly ashes show that the main parameters governing the SiO₂ extraction are: (a) a high bulk SiO₂ content (>52%, for obtaining an extraction yield of 100 g SiO₂ kg^?1) in the starting fly ash, (b) a high proportion (>55%) of the bulk SiO₂ present in the degradable glass matrix and the highly soluble opaline fraction, and (c) a high bulk SiO₂/Al₂O₃ ratio (>2.0) of the fly ash. The results from experiments of zeolite synthesis by direct conversion demonstrate that the most important criteria for the selection of a fly ash for this process are: (a) a high content of Al₂O₃ and SiO₂(>65%) (b) a high glass content (>63%) and (c) relatively low SiO₂/Al₂O₃ ratio (<2.0). Multivariate analysis confirms the importance of the above‐mentioned variables and shows some additional variables that have influence on ash behaviour under alkaline conditions. It quantifies the use of those variables for determining the suitability of ashes for SiO₂ extraction and zeolite synthesis and is able to distinguish between the two. Copyright © 2004 Society of Chemical Industry     

Regulation of BRCA1 and BRCA2 expression in human breast cancer cells by DNA-damaging agents

Germline mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 have been linked to the development of breast cancer, ovarian cancer, and other malignancies. Recent studies suggest that the BRCA1 and BRCA2 gene products may function in the sensing and/or repair of DNA damage. To investigate this possibility, we determined the effects of various DNA-damaging agents and other cytotoxic agents on the mRNA levels of BRCA1 and BRCA2 in the MCF-7 and other human breast cancer cell lines. We found that several agents, including adriamycin (a DNA intercalator and inhibitor of topoisomerase II), camptothecin (a topoisomerase I inhibitor), and ultraviolet radiation induced significant decreases in BRCA1 and BRCA2 mRNA levels. Decreased levels of BRCA1 and BRCA2 mRNAs were observed within 6-12 h after treatment with adriamycin and persisted for at least 72 h. Adriamycin also induced decreases in BRCA1 protein levels; but these decreases required several days. U.V. radiation induced dose-dependent down-regulation of BRCA1 and BRCA2 mRNAs, with significant decreases in both mRNAs at doses as low as 2.5 J/m2, a dose that yielded very little cytotoxicity. Adriamycin-induced down-regulation of BRCA1 and BRCA2 mRNAs was first observed at doses that yielded relatively little cytotoxicity and little or no apoptotic DNA fragmentation. Adriamycin and U.V. radiation induced distinct dose- and time-dependent alterations in the cell cycle distribution; but these alterations did not correlate well with corresponding changes in BRCA1 and BRCA2 mRNA levels. However, the adriamycin-induced reduction in BRCA1 and BRCA2 mRNA levels was correlated with p53 functional status. MCF-7 cells transfected with a dominant negative mutant p53 (143 val-->ala) required at least tenfold higher doses of adriamycin to down-regulate BRCA1 and BRCA2 mRNAs than did parental MCF-7 cells or control-transfected MCF-7 clones. These results suggest that BRCA1 and BRCA2 may play roles in the cellular response to DNA-damaging agents and that there may be a p53-sensitive component to the regulation of BRCA1 and BRCA2 mRNA expression.     

Application of the Repeated Measures (Split-Plot) Design to the Development of Processes for Drug Substances

A case study from the chemical and pharmaceutical industries is used to show the value of the repeated measures design in developing processes for drug substances. This article advocates the use of the repeated measures design in situations that commonly arise in the chemical and pharmaceutical industries when repeated measurements are taken on the same experimental unit, instead of the common practice of comparing only individual conditions, a procedure that is inappropriate in many cases. One of the most important advantages of applying the repeated measures design is the abundance of data that can be obtained by taking into account the entire response curve instead of only isolated individual points on it.     

Beneficial effect on serum apo AI, apo B and Lp AI levels of Ramadan fasting

To investigate the developmental distribution of cochlear nucleus (CN) astrocytes, we used immunocytochemical localization of glial fibrillary acidic protein (GFAP) and S100beta in rats at 0, 5, 10, 15, 21, 30 postnatal days plus the adult. Differential developmental trends were observed for both proteins. The spatial distribution showed a progressive increase of the number of GFAP-immunoreactive (GFAP-IR) astrocytes during development. GFAP positive cells occurred first in the granule cell domain of the ventral CN and in the molecular cell layer of the dorsal CN, then followed an outside to inside pattern of progression. The GFAP-IR reached an adult distribution 1 month after birth. By contrast with GFAP, the apparition of S100beta-immunoreactivity (S100beta-IR) was abrupt (between 0 and 5 days) followed by a rapid stabilization of density and distribution of IR cells (between 15 and 21 days). The developmental distribution of S100beta-IR cells occurred from the posterodorsal region and progressed toward a rostroventral direction. With contrast to GFAP-IR astrocytes, S100beta-positive cells were mainly restricted to the central part of the CN, while only few IR astrocytes were observed in the granule cell domain of the ventral CN or in the molecular cell layer of the dorsal CN. This differential distribution suggests that both antigens were expressed by two different cell populations at least, it is obvious during the first postnatal week. The gradual expression of GFAP and S100beta is interpreted as reflecting the time course of astrocytic maturation. These data suggest that the maturation of CN astrocytes may be linked to the final maturation of CN neurons.     

Relationship of the polymerase chain reaction for cytomegalovirus to the development of hepatitis in liver transplant recipients

In a pilot study, the polymerase chain reaction was found to be more sensitive than standard viral culture methods for the detection of cytomegalovirus, particularly from blood and tissues. We therefore applied this technique to 71 serially collected liver biopsies from 16 orthotopic liver transplant patients. All patients were CMV-seropositive (n = 15) or seroconverted (n = 1). Seven patients (9 biopsies) had histologically proved CMV hepatitis, and all these biopsies were CMV PCR-positive. Six of these 7 patients had a prior liver biopsy that was CMV PCR-positive, but culture and histology-negative, an average of 13.2 +/- 6.9 days before the histologically positive biopsy. The 7th patient was not biopsied prior to the diagnostic biopsy. Three patients had 7 liver biopsies that were CMV PCR-positive, but histologically negative for CMV hepatitis. Two of these three had CMV infection confirmed by viral culture of blood or liver biopsy. The remaining 6 patients had a total of 26 liver biopsies that were negative for CMV by PCR, culture, and histology. Among liver transplant patients, CMV PCR performed on liver biopsy specimens correctly identified all histologically proven cases of CMV hepatitis. CMV PCR positivity in liver tissue did not correlate with latent infection and preceded the development of CMV hepatitis or other meaningful CMV infection in 8 of 10 patients.     

Separation of minerals in electric field by ponderomotive forces (classification in high-voltage vertical capacitor)

A three-electrode capacitor, designed for an alternating electric field, was used to effect the dry separation of materials according to permittivity.A stable fall regime was secured through a isodynamic field of the ponderomotive forces. The solid fractions were arranged in concentric circles about the capacitor axis.Numerical examples were worked out for two-component mixtures of gold and quartz, copper and aluminum, and glass and aluminum.The required voltage on the capacitor plates and the fall distance were determined.