223 research outputs found

    Development of Transparent LSCO and LSCNO Conductors for Optical Shutter Systems

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    We have prepared lanthanum strontium cobalt oxide (La0.50Sr0.50CoO3; LSCO 50/50) and lanthanum strontium cobalt nickel oxide (La0.50Sr0.50Co0.50Ni0.50O3; LSCNO) as candidate transparent electrodes for use in a shutter-based infrared sensor protection device. The shutter device requires that the electrode be transparent (80% transmission) and have moderate sheet resistance (300 Ω/sq.). Because of the effects of film thickness on intrinsic material properties, such as resistivity and extinction coefficient, and simple engineering issues (i.e., the relationship between film thickness, resistance and transmission), films of various thicknesses were prepared to achieve an optimal balance of electrical and optical performance. van der Pauw measurements and FTIR spectroscopy were used to study thin film properties. The best LSCO films prepared demonstrated electrical (438 Ω/sq.) and optical (68% transmission at 8 μm) properties that did not meet the target property goals for this application. However, the LSCNO films (of optimal thickness) offered performance (323 Ω/sq. and 73% transmission) close to the device requirements

    Исследование вариантов объединения на параллельную работу Иркутской и Якутской энергосистем

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    Объектом исследования является параллельна работа Иркутской и Якутской энергосистем. Цель работы – анализ электрических режимов Иркутской и западного района Якутской энергосистем и выбор возможных вариантов их объединения на параллельную работу. В процессе исследования моделировалась рабочая схема при объединение Иркутской и Якутской энергосистем, а также определение МДП и АДП по контролируемому сечению ВЛ 220 кВ ПС Усть-Кут – ПС Бобровка и проверялась динамическая устойчивость при нормативных возмущениях. Произведена оценка различных вариантов объединения двух энергосистем В результате исследования были выявленные наиболее эффективные способы объединения энергосистем.The object of the research is parallel to the work of the Irkutsk and Yakutsk energy systems. Purpose – analysis of electric modes of Irkutsk and Yakutsk western district energy systems and a choice of options for combining them in parallel. The study simulated the working circuit when the union of Irkutsk and Yakutsk energy systems, as well as determining мaximum allowed power flow and emergency power transfer limit on controlled sections line of 220 kV Ust-Kut – Bobrovka and tested the dynamic stability of the regulatory disturbances. An assessment of the different options for combining the two power systems As a result of the study were to identify the most effective ways of interconnection

    Peripheral capillary non-perfusion in asymptomatic Waldenström's macroglobulinemia

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    <p>Abstract</p> <p>Background</p> <p>To report the rare association of peripheral retinal ischemia in a patient with Waldenström's macroglobulinemia.</p> <p>Case Presentation</p> <p>A 39-year old man with a recent diagnosis of asymptomatic Waldenström's macroglobulinemia (WM) was referred from his physician for ocular evaluation. The fundus examination in his right eye (RE) revealed very mild central vein dilation, while retinal hemorrhages associated with microaneurismal alterations of the vascular plexus were detected at the temporal periphery. Fluoroscein angiography of his RE revealed an extended area of capillary dropout distal to the microaneurismal lesions. In our patient with WM an extensive area of capillary non-perfusion, in the absence of severe involvement of the posterior pole was documented; this association to the best of our knowledge has never been reported before.</p> <p>Conclusion</p> <p>Although the incidence of the disease is rare, meticulous examination of the retinal periphery should be performed in all patients with WM and vice versa the differential diagnosis of peripheral retinal ischemia of unknown origin should include an investigation to rule out asymptomatic Waldenström's macroglobulinemia.</p

    Transport of Proteins into Mitochondria

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    The mitochondrial ADP/ATP carrier is an integral transmembrane protein of the inner membrane. It is synthesized on cytoplasmic ribosomes. Kinetic data suggested that this protein is transferred into mitochondria in a posttranslational manner. The following results provide further evidence for such a mechanism and provide information on its details. 1. In homologous and heterologous translation systems the newly synthesized ADP/ATP carrier protein is present in the postribosomal supernatant. 2. Analysis by density gradient centrifugation and gel filtration shows, that the ADP/ATP carrier molecules in the postribosomal fraction are present as soluble complexes with apparent molecular weights of about 120000 and 500000 or larger. The carrier binds detergents such as Triton X-100 and deoxycholate forming mixed micelles with molecular weights of about 200000–400000. 3. Incubation of a postribosomal supernatant of a reticulocyte lysate containing newly synthesized ADP/ATP carrier with mitochondria isolated from Neurospora spheroplasts results in efficient transfer of the carrier into mitochondria. About 20–30% of the transferred carrier are resistant to proteinase in whole mitochondria. The authentic mature protein is also largely resistant to proteinase in whole mitochondria and sensitive after lysis of mitochondria with detergent. Integrity of mitochondria is a prerequisite for translocation into proteinase resistant position. 4. The transfer in vitro into a proteinase-resistant form is inhibited by the uncoupler carbonyl-cyanide m-chlorophenylhydrazone but not the proteinase-sensitive binding. These observations suggest that the posttranslational transfer of ADP/ATP carrier occurs via the cytosolic space through a soluble oligomeric precursor form. This precursor is taken up by intact mitochondria into an integral position in the membrane. These findings are considered to be of general importance for the intracellular transfer of insoluble membrane proteins. They support the view that such proteins can exist in a water-soluble form its precursors and upon integration into the membrane undergo a conformational change. Uptake into the membrane may involve the cleavage of an additional sequence in some proteins, but this appears not to be a prerequisite as demonstrated by the ADP/ATP carrier protein

    Transport of Cytoplasmically Synthesized Proteins into the Mitochondria in a Cell Free System from Neurospora crassa

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    Synthesis and transport of mitochondrial proteins were followed in a cell-free homogenate of Neurospora crassa in which mitochondrial translation was inhibited. Proteins synthesized on cytoplasmic ribosomes are transferred into the mitochondrial fraction. The relative amounts of proteins which are transferred in vitro are comparable to those transferred in whole cells. Cycloheximide and puromycin inhibit the synthesis of mitochondrial proteins but not their transfer into mitochondria. The transfer of immunoprecipitable mitochondrial proteins was demonstrated for matrix proteins, carboxyatractyloside-binding protein and cytochrome c. Import of proteins into mitochondria exhibits a degree of specificity. The transport mechanism differentiates between newly synthesized proteins and preexistent mitochondrial proteins, at least in the case of matrix proteins. In the cell-free homogenate membrane-bound ribosomes are more active in the synthesis of mitochondrial proteins than are free ribosomes. The finished translation products appear to be released from the membrane-bound ribosomes into the cytosol rather than into the membrane vesicles. The results suggest that the transport of cytoplasmically synthesized mitochondrial proteins is essentially independent of cytoplasmic translation; that cytoplasmically synthesized mitochondrial proteins exist in an extramitochondrial pool prior to import; that the site of this pool is the cytosol for at least some of the mitochondrial proteins; and that the precursors in the extramitochondrial pool differ in structure or conformation from the functional proteins in the mitochondria

    Оценка конкурентоспособности организации

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    Цель работы: обозначить пути повышения конкурентоспособности предприятия-производителя электротехнической продукции ООО «СИБАР ГРУПП» В процессе исследования проводились: анализ финансово-хозяйственной деятельности, анализ ассортимента предприятия, выделены основные финансовые показатели деятельности предприятия, проведен анализ конкурентной среды предприятия В результате исследования выявлены слабые места предприятия, рекомендованы меры по повышению конкурентоспособности предприятия на рынке электротехнического оборудования Экономическая эффективность/значимость работы: исполнение рекомендаций для повышения конкурентоспособности В будущем планируется: дальнейшее повышение конкурентоспособности.A research object is LTD "SIBAR GROUP" plant of electrical engineering equipment. Aim of work : to designate the ways of increase of competitiveness of enterprise on the example of enterprise LTD "SIBAR GROUP". In the process of research conducted: analysis of financially-economic activity, analysis of assortment of enterprise, basic financial performance of enterprise indicators are distinguished, the analysis of competition environment of enterprise is conducted. As a result of research the weak points of enterprise are educed, measures are recommended on their strengthening. Basic structural, technological and operating descriptions. Economic efficiency/ is meaningfulness of work : execution of recommendations for the increase of competitiveness

    Is amino acid racemization a useful tool for screening for ancient DNA in bone?

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    Many rare and valuable ancient specimens now carry the scars of ancient DNA research, as questions of population genetics and phylogeography require larger sample sets. This fuels the demand for reliable techniques to screen for DNA preservation prior to destructive sampling. Only one such technique has been widely adopted: the extent of aspartic acid racemization (AAR). The kinetics of AAR are believed to be similar to the rate of DNA depurination and therefore a good measure of the likelihood of DNA survival. Moreover, AAR analysis is only minimally destructive. We report the first comprehensive test of AAR using 91 bone and teeth samples from temperate and high-latitude sites that were analysed for DNA. While the AAR range of all specimens was low (0.02 -0.17), no correlation was found between the extent of AAR and DNA amplification success. Additional heating experiments and surveys of the literature indicated that D/L Asx is low in bones until almost all the collagen is lost. This is because aspartic acid is retained in the bone within the constrained environment of the collagen triple helix, where it cannot racemize for steric reasons. Only if the helix denatures to soluble gelatin can Asx racemize readily, but this soluble gelatine is readily lost in most burial environments. We conclude that Asx D/L is not a useful screening technique for ancient DNA from bone

    The effects of demineralisation and sampling point variability on the measurement of glutamine deamidation in type I collagen extracted from bone

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    The level of glutamine (Gln) deamidation in bone collagen provides information on the diagenetic history of bone but, in order to accurately assess the extent of Gln deamidation, it is important to minimise the conditions that may induce deamidation during the sample preparation. Here we report the results of a preliminary investigation of the variability in glutamine deamidation levels in an archaeological bone due to: a) sampling location within a bone; b) localised diagenesis; and c) sample preparation methods. We then investigate the effects of pre-treatment on three bone samples: one modern, one Medieval and one Pleistocene. The treatment of bone with acidic solutions was found to both induce deamidation and break down the collagen fibril structure. This is particularly evident in the Pleistocene material (∼80,000 years BP) considered in this study. We show that ethylenediaminetetraacetic acid (EDTA), when used as an alternative to hydrochloric acid (HCl) demineralisation, induces minimal levels of deamidation and maintains the collagen fibril structure. Areas of bone exhibiting localised degradation are shown to be correlated with an increase in the levels of Gln deamidation. This indicates that the extent of Gln deamidation could provide a marker for diagenesis but that sampling is important, and that, whenever possible, subsamples should be taken from areas of the bone that are visually representative of the bone as a whole. Although validation of our observations will require analysis of a larger sample set, deamidation measurements could be a valuable screening tool to evaluate the suitability of bone for further destructive collagen analyses such as isotopic or DNA analysis, as well as assessing the overall preservation of bone material at a site. The measure of bone preservation may be useful to help conservators identify bones that may require special long-term storage conditions
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