Optical properties of graphite-like carbon films

A model of the electronic structure of graphite-like carbon films, describing the semiconductor properties of this material, is presented. Spectra of optical constants of microcrystalline carbon films in the region λ = 0.4–8.0 μm were studied by the spectral ellipsometry and IR reflection methods. A number of distinctive features of the spectra, associated with both the appearance of C---C- and C---H_n-type bonds and direct energy gaps, were found. Analysis of the optical data using the proposed model makes possible a common interpretation of our results and literature data. Values of a parameter Θ, which is an averaged qualitative parameter of structural distortions within carbon microcrystallites as compared with crystalline graphite, are determined from comparison of theoretical results and experimental data.     

Expression of bovine beta-lactoglobulin/human erythropoietin fusion protein in the milk of transgenic mice and rabbits

We have generated several transgenic mouse lines and rabbits expressing efficiently (up to 0.3 mg/ml in mice and up to 0.5 mg/ml in rabbits) human erythropoietin in their milk as bovine beta-lactoglobulin fusion protein. Human erythropoietin cDNA was inserted in frame into exon 5 of the bovine beta-lactoglobulin gene with a linker oligonucleotide encoding the cleavage site for bacterial IgA protease. RNA analysis performed on one lactating transgenic mouse and one transgenic rabbit revealed that the fusion gene was expressed almost exlusively in the mammary gland, although low amounts of transgene-derived RNA were detectable in salivary glands and uterus or in the kidney. The fusion protein was specifically cleaved with IgA protease. The erythropoietin part obtained upon digestion had a lower molecular mass than recombinant erythropoietin produced in Chinese hamster ovary cells. By deglycosylation analysis it was shown that the difference in size was due to a different type of glycosylation. Biological activity of the fusion protein, as determined by growth stimulation of TF-1 erythroleukemia cells, was less than 15% of that of human recombinant erythropoietin. Upon digestion of the fusion protein with IgA protease, biological activity comparable to that of the recombinant erythropoietin was recovered. Transgenic males and virgin females did not show signs of enhanced erythropoiesis, but lactating females expressing the transgene displayed transient increases in their hematocrit values.     

Expression of matrix metalloproteinases and their inhibitors in aneurysms and normal aorta

BACKGROUND: Abdominal aortic aneurysms (AAAs) are characterized by degradation of collagen and elastin resulting from increases in matrix metalloproteinase (MMP) activity. Previous authors have identified isolated increases in expression of specific MMPs in AAAs, but none have compared relative levels of expression of particular MMPs to one another or to those of their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). This study proposes to quantify relative mRNA levels for interstitial collagenase (MMP-1), 72 kd type IV collagenase (MMP-2), 92 kd type IV collagenase (MMP-9), TIMP-1, and TIMP-2 in normal aorta (NA) and AAA to provide insight as to the relative importance of each in aneurysm formation. METHODS: Competitive polymerase chain reactions (PCRs) with gene-specific external standards and cDNA derived from AAAs (n = 8; mean age, 67.4 years) and NA (n = 5; mean age, 40.6 years) were used to quantify mRNA levels. Results were normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA levels, determined by means of competitive PCR, and compared by means of Mann-Whitney statistics. RESULTS: Significant increases in MMP mRNA expression in AAA over NA were observed for MMP-1 (3.64 versus 0.3, p = 0.007), MMP-9 (78.03 versus 3.35, p = 0.003), TIMP-1 (835.32 versus 477.2, p = 0.027), and TIMP-2 (18.09 versus 4.14, p = 0.003). The ratio of MMP to TIMP mRNA levels was higher in AAA than NA (0.135 versus 0.045, p = 0.018). CONCLUSIONS: Increases in expression of MMP-1, MMP-9, and MMP/TIMP ratios may result in increased proteolysis and matrix degradation, which characterize AAAs. MMP-9 appears to be the predominant metalloproteinase expressed in AAA, because its mRNA levels were more than 20 times and 2 times higher than those of MMP-1 and MMP-2, respectively. TIMP-1 mRNA levels were in molar excess to those of any of the metalloproteinases studied.     

Activation energy of electron-stimulated quenching of the photoluminescence of n-type porous silicon

The degradation of photoluminescence of porous silicon by kilovolt electrons and the mechanism and activation energy of this process have been investigated. Quantitative relations between the integral intensity of the photoluminescence and the irradiation dose and substrate temperature are obtained. The mechanism of the process is discussed and its activation energy is determined. Pis’ma Zh. Tekh. Fiz. 23, 44–50 (September 26, 1997)     

Methods to compare dissolution profiles and a rationale for wide dissolution specifications for metoprolol tartrate tablets

The objectives of this work were to apply several profile comparison approaches to dissolution data of four different but bioequivalent metoprolol tartrate tablet formulations to (1) identify the advantages and disadvantages of each approach, (2) quantify the metric for comparing dissolution profiles of each method, (3) determine metric limits that are consistent with the observed bioequivalence, and (4) rationalize the observed metric limits with respect to the role of dissolution in overall metoprolol absorption. Dissolution was performed by the USP monograph method on four formulations of metoprolol tartrate tablets (Lopressor plus fast, medium, and slow dissolving test formulations). Three general approaches to compare dissolution profiles were examined; they were ANOVA-based, model-independent, and model-dependent approaches. It is concluded that model-independent approaches and several model-dependent approaches yielded numerical results that can serve as objective and quantitative metrics for comparing entire dissolution profiles of the four metoprolol tartrate formulations. However, these methods presented complications. Some metrics were dependent on the length of the dissolution profile and the sampling scheme. Results from the pairwise procedures also depended on the pairing assignment of individual profiles. In spite of complications, these methods suggested wide dissolution specification limits. Wide dissolution specifications were rationalized through an analysis of in vitro-in vivo relationships, which indicated metoprolol dissolution from these formulations was not the rate-limiting step; hence, a range of dissolution profiles can be expected to yield equivalent plasma profiles.     

Oxygenation in the rabbit myocardium: assessment with susceptibility-dependent MR imaging

PURPOSE: To determine the feasibility of using hemoglobin (Hb) desaturation as an indicator of myocardial oxygenation. MATERIALS AND METHODS: High-resolution gradient-echo nuclear magnetic resonance (MR) images of isolated, blood-perfused rabbit hearts were obtained at various blood oxygenation levels. The hearts were perfused at 37 degrees C with a Langendorff apparatus modified for nuclear MR imaging. The perfusate contained bovine red blood cells in a cardioplegic solution that eliminated motion artifacts and minimized arteriovenous oxygenation differences. Hb saturation was varied (7%-100%) randomly. Perfusion pressure was continuously monitored, and blood samples were obtained. RESULTS: There was a substantial correlation between image signal intensity in the myocardium and Hb saturation in the blood, believed to be due to susceptibility effects of the paramagnetic species deoxyhemoglobin. CONCLUSION: Direct and noninvasive determination of regional Hb saturation with susceptibility-dependent MR imaging may provide information regarding regional myocardial O2 content.     

A functional model of the electrical potential of skin

A model of the skin electrical potential has been developed. It contains electrical and functional parameters of the sweating and their dependence on efferent innervation. The analytical expression of the skin electrical potential which explains basic experimental results has been constructed.     

Necrotizing fasciitis of the face

Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with high morbidity and mortality rates. Its occurrence in the head and neck region is uncommon, the majority of reported cases being limited to involvement of the neck, usually from infections of dental or pharyngeal origin. Involvement of the face from NF is rare; only 35 such cases have been reported in the literature since 1960. It is not only associated with a high mortality but can also result in severe disfigurement of the face, posing challenging reconstructive problems. Successful management of facial NF requires early diagnosis, prompt institution of broad spectrum antibiotics, aggressive surgical debridement to control the infection, and reconstruction of the resultant soft tissue defects. This report describes four additional cases of facial necrotizing fasciitis. One of the four patients died as a result of sepsis and multi-organ system failure. Two of the three surviving patients had significant facial disfigurement. A comprehensive review of the facial NF cases reported in the literature is also provided. Based on our experience with facial NF and the results of all previous case reports, the clinical manifestations, pathogenesis, and management of this disease are discussed.     

Dual-purpose technologies in view of diversification of the military-industrial complex of Russia

Current problems in scientific-information support of the process of diversification of the military-industrial complex (or defense-industrial complex, DIC) of Russia are considered, which can facilitate the effective usage of dual-purpose technologies in various civilian fields of the national economy. In this context, the program of the 7th Specialized Exhibition “Dual-Purpose Products and Technologies: DIC Diversification,” which was held in Moscow in October 2006, is analyzed.