Simple Metals at High Pressure

In this lecture we review high-pressure phase transition sequences exhibited by simple elements, looking at the examples of the main group I, II, IV, V, and VI elements. General trends are established by analyzing the changes in coordination number on compression. Experimentally found phase transitions and crystal structures are discussed with a brief description of the present theoretical picture.Comment: 22 pages, 4 figures, lecture notes for the lecture given at the Erice course on High-Pressure Crystallography in June 2009, Sicily, Ital

Effect of pressure on the Raman modes of antimony

The effect of pressure on the zone-center optical phonon modes of antimony in the A7 structure has been investigated by Raman spectroscopy. The A_g and E_g frequencies exhibit a pronounced softening with increasing pressure, the effect being related to a gradual suppression of the Peierls-like distortion of the A7 phase relative to a cubic primitive lattice. Also, both Raman modes broaden significantly under pressure. Spectra taken at low temperature indicate that the broadening is at least partly caused by phonon-phonon interactions. We also report results of ab initio frozen-phonon calculations of the A_g and E_g mode frequencies. Presence of strong anharmonicity is clearly apparent in calculated total energy versus atom displacement relations. Pronounced nonlinearities in the force versus displacement relations are observed. Structural instabilities of the Sb-A7 phase are briefly addressed in the Appendix.Comment: 10 pages, 8 figure

BCG-INDUCED PRO-INFLAMMATORY PHENOTYPE OF MESENCHYMAL STEM CELLS: EFFECT OF IMMUNE MODULATORS

In case of mycobacterial infection the granulomatous infiltration foci contain the significant amount of mesenchymal stem cells (MSC), which functional phenotype and respective function in anti-tuberculosis immune defense remain unknown.Goal of the study: to characterize the MSC phenotype, formed by their interaction with BCG of M. bovis and to evaluate the changes in this phenotype caused by the action of inhibitors and stimulants of immune regulatory action.Materials and methods: MSC retrieved from bone marrow of mice were cultured with the presence and absence of BCG of M. bovis and/or poludanum TLR3 agonist; and the effect of two latter on the production of pro- and anti-inflammatory cytokines was evaluated by enzyme multiplied immunoassay. Flow cytometry and radioactive testing were used to evaluate the impact of cultured BCG fluid and poludanum-conditioned MSC on the proliferative and apoptotic activity of splenocytes. The inhibitors of indoleamine 2,3-dioxygenase (IDO), cyclooxygenase-2 (COG-2) or NO synthase were added to certain cultures alone with BCG and poludanum, and the contributions of IDO, COG-2 and NO to BCG and poludanum-induced response were assessed.Results. Pro-inflammatory polarization of MSC under the action of BCG and poludanum was demonstrated. Pro-inflammatory MSC phenotype correlated to their anti-apoptogenic and growth-stimulating actions on the splenocytes. It was demonstrated that IDO and NO restrained BCG-induced polarization and conversely COG-2 promoted BCG-induced pro-inflammatory polarization of MSC.Conclusions. 1. MSC actively participate in the formation of immunologic anti-mycobacterial resistance. 2. Targeted regulation of IDO and NO production can be feasibly applied for formation of anti-tuberculous vaccinal immunity and control mycobacterial infection

Structural and chemical embrittlement of grain boundaries by impurities: a general theory and first principles calculations for copper

First principles calculations of the Sigma 5 (310)[001] symmetric tilt grain boundary in Cu with Bi, Na, and Ag substitutional impurities provide evidence that in the phenomenon of Bi embrittlement of Cu grain boundaries electronic effects do not play a major role; on the contrary, the embrittlement is mostly a structural or "size" effect. Na is predicted to be nearly as good an embrittler as Bi, whereas Ag does not embrittle the boundary in agreement with experiment. While we reject the prevailing view that "electronic" effects (i.e., charge transfer) are responsible for embrittlement, we do not exclude the role of chemistry. However numerical results show a striking equivalence between the alkali metal Na and the semi metal Bi, small differences being accounted for by their contrasting "size" and "softness" (defined here). In order to separate structural and chemical effects unambiguously if not uniquely, we model the embrittlement process by taking the system of grain boundary and free surfaces through a sequence of precisely defined gedanken processes; each of these representing a putative mechanism. We thereby identify three mechanisms of embrittlement by substitutional impurities, two of which survive in the case of embrittlement or cohesion enhancement by interstitials. Two of the three are purely structural and the third contains both structural and chemical elements that by their very nature cannot be further unravelled. We are able to take the systems we study through each of these stages by explicit computer simulations and assess the contribution of each to the nett reduction in intergranular cohesion. The conclusion we reach is that embrittlement by both Bi and Na is almost exclusively structural in origin; that is, the embrittlement is a size effect.Comment: 13 pages, 5 figures; Accepted in Phys. Rev.

ДИФФУЗИОННО-ТЕНЗОРНАЯ МРТ ПРИ ТРИГЕМИНАЛЬНОЙ НЕВРАЛГИИ, ВЫЗВАННОЙ ВАЗОНЕВРАЛЬНЫМ КОНФЛИКТОМ

Diffusion-tensor imaging in modern MR units is perspective tool for creation of tracts of brain white matter. Most often reason for trigeminal neuralgia (TN) is vascular compression. Very important part in pain pathogenesis is played by structural changes, due to demyelination of trigeminal nerve root, caused by compression. Studying of structural changes of trigeminal nerve root in trigeminal neuralgia with DTI could clear influence of vascular compression for development of TN. The aim of this study was to estimate fractional anisotropy changes in trigeminal nerve root. Study included 33 patients with TN, who underwent microvascular decompression. Some of patients also had manipulation on trigeminal nerve root in anamnesis. It was revealed that fractional anisotropy (FA) is linked with compression degree and TN type — the less FA the higher the degree. After estimation of DTI it was revealed that FA is the less when patient had on trigeminal nerve root in anamnesis. Obtained data show changes that DTI could be helpful in choice of treatment tactics, allowing to demonstrate link of trigeminal root changes with compression. Диффузионно-тензорная визуализация (DTI) на современных МР-томографах стала перспективным инструментом для построения и оценки ориентации трактов в белом веществе мозга. Наиболее частой причиной развития тригеминальной невралгии (ТН) является контакт между сосудистыми и нервными структурами с их компрессией. Важное место в патогенезе боли занимают структурные изменения, связанные с демиелинизацией нервных волокон вследствие компрессии. Изучение структурных изменений корешка тройничного нерва (КТН) при три- геминальной невралгии, обусловленной нейроваскулярным конфликтом, может прояснить влияние компрессии в  патогенезе ТН. Цель данного исследования  — оценка изменений фракционной анизотропии в  тройничном нерве при сосудистой компрессии. В исследование были включены 33 пациента с тройничной невралгией, часть из которых имела предшествующие манипуляции на больной стороне на нерве в анамнезе. Всем больным выполнена микроваскулярная декомпрессия. При оценке однородности структуры КТН по данным DTI выявлено, что степень снижения анизотропии связана со степенью компрессии нерва сосудом. В группе пациентов с вмешательствами на КТН и/или гассеровом узле в анамнезе наблюдалось более значимое снижение ФА на пораженной стороне. Полученные данные позволяют говорить о том, что DTI может помочь при выборе тактики лечения, позволяя связать изменения в нерве с сосудистой компрессией и степенью ее выраженности.

БЦЖ-ИНДУЦИРОВАННЫЙ ПРОВОСПАЛИТЕЛЬНЫЙ ФЕНОТИП МЕЗЕНХИМАЛЬНЫХ СТВОЛОВЫХ КЛЕТОК: ВЛИЯНИЕ ИММУНОМОДУЛЯТОРОВ

In case of mycobacterial infection the granulomatous infiltration foci contain the significant amount of mesenchymal stem cells (MSC), which functional phenotype and respective function in anti-tuberculosis immune defense remain unknown.Goal of the study: to characterize the MSC phenotype, formed by their interaction with BCG of M. bovis and to evaluate the changes in this phenotype caused by the action of inhibitors and stimulants of immune regulatory action.Materials and methods: MSC retrieved from bone marrow of mice were cultured with the presence and absence of BCG of M. bovis and/or poludanum TLR3 agonist; and the effect of two latter on the production of pro- and anti-inflammatory cytokines was evaluated by enzyme multiplied immunoassay. Flow cytometry and radioactive testing were used to evaluate the impact of cultured BCG fluid and poludanum-conditioned MSC on the proliferative and apoptotic activity of splenocytes. The inhibitors of indoleamine 2,3-dioxygenase (IDO), cyclooxygenase-2 (COG-2) or NO synthase were added to certain cultures alone with BCG and poludanum, and the contributions of IDO, COG-2 and NO to BCG and poludanum-induced response were assessed.Results. Pro-inflammatory polarization of MSC under the action of BCG and poludanum was demonstrated. Pro-inflammatory MSC phenotype correlated to their anti-apoptogenic and growth-stimulating actions on the splenocytes. It was demonstrated that IDO and NO restrained BCG-induced polarization and conversely COG-2 promoted BCG-induced pro-inflammatory polarization of MSC.Conclusions. 1. MSC actively participate in the formation of immunologic anti-mycobacterial resistance. 2. Targeted regulation of IDO and NO production can be feasibly applied for formation of anti-tuberculous vaccinal immunity and control mycobacterial infection. При микобактериальной инфекции в очагах гранулематозной инфильтрации содержится большое количество мезенхимальных стволовых клеток (МСК), функциональный фенотип которых и, соответственно, функция в противотуберкулезном иммунитете неизвестны.Цель исследования: охарактеризовать фенотип МСК, формирующийся при их взаимодействии с M. bovis БЦЖ, и оценить изменения этого фенотипа под действием ингибиторов и стимуляторов иммунорегуляторной активности.Материалы и методы: МСК, полученные из костного мозга мышей, культивировали в присутствии или отсутствии M. bovis БЦЖ и/или агониста TLR3 полудана и методами иммуноферментного анализа оценивали влияние последних на продукцию про- и антивоспалительных цитокинов. Методами проточной цитометрии и радиоактивного анализа оценивали влияние культуральной жидкости БЦЖ- и полудан-кондиционированных МСК на пролиферативную и апоптотическую активность спленоцитов. В часть культур вместе с БЦЖ или полуданом добавляли ингибиторы индоламин-2,3-диоксигеназы (ИДО), циклооксигеназы-2 (ЦОГ-2) или NO синтазы и оценивали вклад ИДО, ЦОГ-2 и NO в БЦЖ- и полудан-индуцированный ответ.Результаты. Показана провоспалительная поляризация МСК под действием БЦЖ и полудана. Провоспалительный фенотип МСК коррелировал с их антиапоптогенной и ростостимулирующей активностью по отношению к спленоцитам. Продемонстрировано, что ИДО и NO сдерживают БЦЖ-индуцированную поляризацию, а активность ЦОГ-2, наоборот, способствует БЦЖ-индуцированной провоспалительной поляризации МСК.Выводы. 1. МСК являются активными участники формирования иммунологической антимикобактериальной резистентности. 2. Таргетное регулирование продукции ИДО и оксида азота может быть целесообразно для формирования противотуберкулезного вакцинального иммунитета и для борьбы с микобактериальной инфекцией

ВОЗМОЖНОСТИ СОВРЕМЕННОЙ ДИАГНОСТИКИ ГЕРПЕСВИРУСНЫХ ИНФЕКЦИЙ У ДЕТЕЙ

Medical history, clinical and laboratory data were studied in 828 children aged from 2 months to 14 years. All of them had different clinical forms of herpesvirus infections (HVI). The combination of the information allows to form the etiologic diagnosis timely and to evaluate the activity of the current infection. Given the polymorphism of clinical symptoms of HVI, it was very important to determine herpesvirus genomes in three media (blood, saliva, urine) by PCR, and high titers of G-antibodies (439 u for CMV and 212.3 u for HHV-6). У 828 детей в возрасте от 2 месяцев до 14 лет с различными клиническими формами герпесвирусных инфекций (ГВИ) были исследованы анамнестические, клинические и лабораторные данные, сочетание которых позволяет своевременно ставить этиологический диагноз и оценивать активность текущего инфекционного процесса. Учитывая полиморфизм клинических симптомов ГВИ, была показана высокая диагностическая значимость определения геномов герпесвирусов в трех средах (кровь, слюна, моча) методом ПЦР и высоких титров G-антител (439 ед. для ЦМВ и 212,3 ед. для ВГЧ-6).

Subchronic systemic toxicity and bioaccumulation of Fe3O 4 nano- and microparticles following repeated intraperitoneal administration to rats

Aqueous suspensions of 10 nm, 50 nm, or 1 μm Fe3O4 particles were injected intraperitoneally (ip) to rats at a dose of 500 mg/kg in 4 mL of sterile deionized water 3 times a week for 5 weeks. Following exposure, functional and biochemical indices and histopathological examinations of spleen and liver tissues of exposed rats were evaluated for signs of toxicity. The iron content of the blood was measured photometrically, and that of the liver and the spleen by atomic adsorption spectroscopy (AAS) and electron paramagnetic resonance (EPR) methods. It was found that, given equal mass doses, Fe3O4 nanoparticles possess considerably higher systemic toxicity than microparticles, but within the nanometric range the relationship between particle size and resorptive toxicity is intricate and nonunique. The latter fact may be attributed to differences in different nanoparticles' toxicokinetics, which are controlled by both more or less substantial direct penetration of nanoparticles through biological barriers and their unequal solubility. © The Author(s) 2011.The author(s) disclosed receipt of the following financial support for the research and/or authorship of this article: Financial support provided by Russian Federal Agency of Science and Innovations

Lattice dynamics study of HgGa2Se4 at high pressures

We report on Raman scattering measurements in mercury digallium selenide (HgGa2Se4) up to 25 GPa. We also performed, for the low-pressure defect-chalcopyrite structure, lattice-dynamics ab initio calculations at high pressures which agree with experiments. Measurements evidence that the semiconductor HgGa2Se4 exhibits a pressure-induced phase transition above 19 GPa to a previously undetected structure. This transition is followed by a transformation to a Raman-inactive phase above 23.4 GPa. On downstroke from 25 GPa until 2.5 GPa, a broad Raman spectrum was observed, which has been attributed to a fourth phase, and whose pressure dependence was followed during a second upstroke. Candidate structures for the three phases detected under compression are proposed. Finally, we also report and discuss the decomposition of the sample by laser heating at pressures close to 19 GPa. As possible products of decomposition, we have identified at least the formation of trigonal selenium nanoclusters and cinnabar-type HgSe.This study was supported by the Spanish government MEC under Grant No. MAT2010-21270-004-01/03/04, by MALTA Consolider Ingenio 2010 project (CSD2007-00045), by Generalitat Valenciana through project GVA-ACOMP-2013-012, and by the Vicerrectorado de Investigacion y Desarrollo of the Universidad Politecnica de Valencia (UPV2011-0966 and UPV2011-0914). E.P.-G., J.L.-S., A.M., and P.R.-H. acknowledge computing time provided by Red Espanola de Super-computacion (RES) and MALTA-Cluster.Vilaplana Cerda, RI.; Gomis Hilario, O.; Manjón Herrera, FJ.; Ortiz, HM.; Pérez González, E.; López Solano, J.; Rodríguez Hernández, P.... (2013). Lattice dynamics study of HgGa2Se4 at high pressures. Journal of Physical Chemistry C. 117(30):15773-15781. https://doi.org/10.1021/jp402493rS15773157811173

Диагностическая ценность прокальцитонина и С-реактивного белка при врожденных инфекциях у детей с экстремально низкой и очень низкой массой тела при рождении

The high frequency of infectious complications in the early neonatal period of adaptation in infants with extremely low (ELBW) and very low birth weight (VLBW) attracts particular attention. The aim of our study was to evaluate the sensitivity (Se) and specificity (Sp) of C-reactive protein and procalcitonin in congenital pneumonia and congenital sepsis in newborn infants with extremely low and very low birth weight.Methods. In 160 preterm newborns that were included in our prospective study, 33 had early neonatal sepsis, 42 children had congenital pneumonia, and 85 infants were without neonatal infection. A comprehensive clinical and laboratoryinstrumental examination of the newborn was done, including determining the concentration of C-reactive protein and procalcitonin at the age of 48–72 hours of life. Results. Low sensitivity of CRP at the age of 48–72 hours of life in congenital sepsis and congenital pneumonia was observed. However, under these pathological conditions CRP and PCT are characterized by high specificity. It should also be noted that PCT has a high sensitivity in children with congenital sepsis aged 48–72 hours. Moreover, PCT also has a high specificity (Sp 80,6%), which determines its advantage in the use of sepsis diagnosis in extremely premature infants compared to CRP.Conclusion. Maximum specificity reaches 100%, co-located with the assessment of CRP and PCT, which determines the feasibility of using this combination for verification of congenital infectious conditions such as sepsis and pneumonia in children ELBW and VLBW aged 48–72 hours.Актуальность. Высокая частота инфекционных осложнений в раннем неонатальном периоде у новорожденных с экстремально низкой (ЭНМТ) и очень низкой массой тела (ОНМТ) при рождении обусловливает необходимость ранней диагностики для уменьшения количества осложнений. Цель: оценка чувствительности и специфичности С-реактивного белка (СРБ) и прокальцитонина (ПКТ) при врожденной пневмонии и врожденном сепсисе у новорожденных детей с ЭНМТ и ОНМТ. Пациенты и методы. В проспективное когортное исследование включено 160 новорожденных с ЭНМТ и ОНМТ, из них 33 с врожденным сепсисом, 42 с врожденной пневмонией, 85 с основным диагнозом респираторного дистресс-синдрома. В первые 48–72 ч жизни новорожденным проводилось комплексное клиническое и лабораторно-инструментальное обследование, включающее определение концентрации СРБ и ПКТ.Результаты. Отмечена невысокая чувствительность СРБ в первые 48–72 ч жизни при врожденном сепсисе и врожденной пневмонии. Однако, при данных патологических состояниях и СРБ, и ПКТ характеризуются высокой специфичностью. Следует также отметить, что ПКТ обладает высокой чувствительностью в первые 48–72 ч жизни у детей с врожденным сепсисом. Кроме того, данный показатель имеет также высокую специфичность (80,6%), что определяет преимущество его изолированного использования по сравнению с СРБ при диагностике врожденного сепсиса у глубоконедоношенных детей. Заключение. Максимальная специфичность, достигающая 100%, выявлена при сочетанной оценке СРБ и ПКТ, что определяет целесообразность использования данной комбинации для верификации таких врожденных инфекционных состояний, как сепсис и пневмония, у детей с ЭНМТ и ОНМТ в возрасте 48–72 ч