Brillouin Scattering Studies of La_{0.77}Ca_{0.23}MnO_3 Across Metal-Insulator Transition

Temperature-dependent Brillouin scattering studies have been carried out on La_{0.77}Ca_{0.23}MnO_3 across the paramagnetic insulator - ferromagnetic metal (I-M) transition. The spectra show a surface Rayleigh wave (SRW) and a high velocity pseudo surface acoustic wave (HVPSAW) besides bulk acoustic waves (BAW). The Brillouin shifts associated with SRW and HVPSAW show blue-shifts, where as the frequencies of the BAW decrease below the I-M transition temperature (T_C) of 230 K. These results can be understood based on the temperature dependence of the elastic constants. We also observe a central peak whose width is maximum at T_C.Comment: 7 pages, 8 figure

Relationship of lithogenesis and oxidative damage in experimental nephrolithiasis

Introduction: Modern literature indicates that tissue damage in the kidneys is an important factor in the formation of urinary stones. It is recognized that the deposits of calcium salts are capable of inducing tissue reactions in the epithelium of the distal tubules and collecting tubules, particularly activating the process of free radical oxidation. Material and Methods: The morphological study of 60 rat kidneys with experimental oxalate nephrolithiasis was conducted. To identify the calcium deposited, silver impregnation by von Kossas method was used. Using immunohistochemistry, the expression of the severity indices of oxidative damage (malondialdehyde - MDA) and antioxidant defenses (mitochondrial superoxide dismutase - SOD-2) were determined. Results: After 3 weeks of the nephrolithiasis modeling in the epithelium of the collecting tubules, in the interstitium of the medulla substance, in the lumen of collecting tubules numerous calcium deposits were found (mean 21.4±3.40 in the field of view). The average size of the deposits was observed to be 16.510.60 mm. In 10% relatively large microlites (up to 30-35 pm) were found with obturation of the lumen of the collecting tubules. Noted decreased expression (1+) of SOD-2 in epitheliocytes. The weakening expression of the antioxidant enzyme was accompanied by a statistically significant elevation of lipid peroxidation products (2+).With using of a-tocopherol in the experiment, a much smaller intensity of histopathological kidney restructuring was determined. The moderate amount (up to 17.612.39 in the field of view) of calcium compounds were small, averaging 5.4010.28 mm in size. Large compounds of calcium, obturation clearance tubules and collecting tubules, or inlays their epithelium were not detected. Immunohistochemical study of the rat kidney during treatment with a-tocopherol showed moderate (2 i) expression of the SOD-2 in epitheliocytes of the collecting tubules, comparable to the intact group and significantly (12.5%) higher than in animals with an experimental model oxalate nephrolithiasis. The intensity of the expression of MDA was similar to that in the intact group and significantly lower in animals with the experimental oxalate nephrolithiasis. Conclusion: During the simulation of the experimental oxalate nephrolithiasis in the rat kidney, marked morphological signs of oxidative damage activation in the tissues and cells and a weakening of the enzymatic antioxidant defense system, accompanied by an acceleration lithogenesis were noted. The usage of antioxidants has beneficial effects on the renal morphologic reorganization, as it reduces the degree of oxidative damage to the cells and tissues, while it helps to reduce the number and size of the calcium deposits formed

Brillouin scattering studies in Fe3_3O4_4 across the Verwey transition

Brillouin scattering studies have been carried out on high quality single crystals of Fe$_3$O$_4$ with [100] and [110] faces in the temperature range of 300 to 30 K. The room temperature spectrum shows a surface Rayleigh wave (SRW) mode at 8 GHz and a longitudinal acoustic (LA) mode at 60 GHz. The SRW mode frequency shows a minimum at the Verwey transition temperature $T_V$ of 123 K. The softening of the SRW mode frequency from about 250 K to $T_V$ can be quantitatively understood as a result of a decrease in the shear elastic constant C$_{44}$, arising from the coupling of shear strain to charge fluctuations. On the other hand, the LA mode frequency does not show any significant change around $T_V$, but shows a large change in its intensity. The latter shows a maximum at around 120 K in the cooling run and at 165 K in the heating run, exhibiting a large hysteresis of 45 K. This significant change in intensity may be related to the presence of stress-induced ordering of Fe$^{3+}$ and Fe$^{2+}$ at the octahedral sites, as well as to stress-induced domain wall motion.Comment: 14 pages, 3 figures, accepted in Physical Review B 200

Effect of substrate roughness on growth of diamond by hot filament CVD

Polycrystalline diamond coatings are grown on Si (100) substrate by hot filament CVD technique. We investigate here the effect of substrate roughening on the substrate temperature and methane concentration required to maintain high quality, high growth rate and faceted morphology of the diamond coatings. It has been shown that as we increase the substrate roughness from 0.05 μm to 0.91 μm (Centre Line Average or CLA) there is enhancement in deposited film quality (Raman peak intensity ratio of sp 3 to non-sp 3 content increases from 1.65 to 7.13) and the substrate temperature can be brought down to 640°C without any additional substrate heating. The coatings grown at adverse conditions for sp 3 deposition has cauliflower morphology with nanocrystalline grains and coatings grown under favourable sp 3 condition gives clear faceted grains

Renal structure reorganisation early in the development of experimental nephrolithiasis model

The results of kidney medulla morphological study from Wistar rats with ethylenglycol oxalate nephrolithiasis model are analyzed. Alteration of internal and external medulla, calcium deposits allocation characteristics are evaluated

Morphological characteristic during third week experimental nephrolithiasis model

The results of kidney medulla morphological study from Wistar rats with ethylenglycol oxalate nephrolithiasis model are analyzed. Alteration of internal and external medulla, microliths allocation characteristics are evaluated

Политическая аккомодация культурных различий в индустриально развитых обществах

The notion of "political accommodation" applied to the theory and practice of managing cultural diversity could enrich the Russian academic dictionary. Liberal democratic states invented specific mechanisms for political accommodation of cultural differences. Thanks to these mechanisms, the part of the population of a democratic state that is not ready to dissolve into the ethnocultural majority is more or less protected. The law not only prohibits forced assimilation, but also contains a number of norms that allow ethnocultural minorities to maintain their distinctiveness by passing it on from generation to generation. However, this is the case in liberal democracies with a long history. In states that emerged as a result of the collapse of two multinational policies - Yugoslavia and the USSR - the situation sometimes looks quite specific. They take more active measures for cultural homogenization than in previous years. As for Russia, in recent years there have been symptomatic changes in the sphere of ethno-cultural policy, which, although with a number of reservations, can be described in terms of "nationalization"

Морфоструктурные варианты клеточно-стромальных взаимодействий в очаге деструкции при острых абсцессах и гангрене легкого в связи с процессами фибринообразования и фибриностабилизации

Purulent and destructive lung diseases are often complicated by loss of anatomic structure of lung tissue, development of lung cirrhosis with subsequent respiratory and heart failure. We performed pathomorphological examination of operational and post mortem lung tissue specimens from 116 inpatients of 25 to 78 years of age with acute lung abscess or lung gangrene who was treated at a pulmonology center from 1999 to 2005. Acute lung inflammation tending to suppuration was characterized by pronounced cell reaction with no "fibrin blockage" and resulted in extended histolysis and abscess formation. "Young" fibrin was often found. Microvessels were fully passable, full-blooded with no fibrin into lumen. At subacute stage, fibrin was "maturing" with subsequent organization and growth of granulated tissue. Clinically, there were sequestered lung abscesses. Massive deposits of "young" and "maturing" fibrin formed "fibrin cocoon" with macrophages and neutrophils bricked up inside. Cell reaction was weak. There were swelling and desquamation of endothelium of microvessels, massive fibrin deposits into vessel lumen and prominent perivascular impregnation with fibrin. This pathological variant could lead to formation of abscess or pulmonary fibrosis with carnification. In cases of massive subtotal or total, often bilateral lung injury with weak delimiting of purulent and destructive process massive destructive zones with resting lung parenchyma faintly impregnated with fibrin were seen. There were no features of fibrin deposition inside microvessels. Functional activity of neutrophils and macrophages was greatly decreased. Therefore, the most favourable pathohistological variant appears to be formation of fibrin blockage consisted of "young" fibrin deposits; prominent cell reaction and absence of microcirculatory block. Structural changes of cells and stroma should be considered during pathological examination in order to provide optimal treatment strategy.Разрешение гнойно-деструктивных процессов в легочной ткани нередко сопровождается потерей анатомических структур с формированием пневмоцирроза и развитием легочно-сердечной недостаточности. Проведено патоморфологическое исследование операционного и секционного материала легких 116 пациентов в возрасте от 25 до 78 лет с острыми абсцессами и гангреной легких, находившихся на стационарном лечении в пульмонологическом центре с 1999 г. по 2005 г. При остром воспалении с тенденцией к нагноению в очаге повреждения легочной ткани определялось большое количество клеточных популяций без образования "фибринового блока", что вело к распространенному гистолизу с формированием абсцесса. Часто определялся очень "молодой" фибрин. Сосуды микроциркуляторного русла были проходимы практически на всем протяжении и характеризовались полнокровием без признаков фибринообразования. В подострый период развития патологического процесса происходило "созревание" фибрина с последующей организацией и разрастанием грануляционной ткани. Клинически у больных выявлялись абсцессы легкого с секвестрацией. Массивные отложения "молодого" и "созревающего" фибрина формировали своеобразный "фибриновый кокон" с "вмонтированными" внутрь макрофагами и нейрофилами и сниженной клеточной реакцией. В сосудах микроциркуляторного русла отмечалось набухание и слущивание эндотелия, массивное отложение фибрина с нарушением проходимости сосудов на фоне выраженной периваскулярной фибринации тканей. В подобном случае возможно развитие как абсцесса, так и пневмофиброза с тенденцией к карнификации. При обширном субтотальном и тотальном, часто двустороннем, поражении легочной ткани со слабо выраженной тенденцией к отграничению гнойно-деструктивного процесса выявлялись обширные зоны деструкции с остатками слабо фибринизированной легочной паренхимы без признаков фибринообразования в сосудах микроциркуляторного русла; функциональная активность нейтрофилов и макрофагов была значительно снижена. Таким образом, наиболее благоприятными вариантами патогистологических изменений следует считать формирование фибринового блока из "молодых" фибриновых депозитов, выраженную клеточную реакцию и отсутствие блокады микроциркуляции. Структурные закономерности клеточно-стромальных преобразований должны учитываться при морфологическом исследовании для выбора правильной тактики лечения данной патологии