64 research outputs found

    Inhomogeneous charged pion condensation phenomenon in the NJL2_2 model with quark number and isospin chemical potentials

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    The properties of two-flavored massive Nambu--Jona-Lasinio model in (1+1)-dimensional spacetime are investigated in the presence of isospin and quark number chemical potentials. The consideration is performed in the large-NcN_c limit, where NcN_c is the number of colored quarks. It is shown in the framework of this model that charged pion condensation phenomenon of dense quark/hadron isotopically asymmetric matter is rather a spatially inhomogeneous than a homogeneous one.Comment: 11 pages, 8 figures; version accepted for publication in PRD. arXiv admin note: text overlap with arXiv:1106.2928, arXiv:1102.407

    Chiral density waves in the NJL2_2 model with quark number and isospin chemical potentials

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    We investigate the phase portrait of the (1+1)-dimensional massless two-flavored NJL2_2 model containing a quark number chemical potential μ\mu and an isospin chemical potential μI\mu_I in the limit of a large number of colors NcN_c\to\infty. Particular attention is paid to the question to what extent the inclusion of an isospin asymmetry affects chiral condensates to have a spatial inhomogeneity in the form of the so-called chiral density waves (CDW) (chiral spirals). It is shown that at zero temperature and comparatively small values of μ\mu, i.e. at μ<μc0.68M0\mu<\mu_c\approx 0.68M_0 (M0M_0 is the dynamical quark mass in the vacuum) only the homogeneous charged pion condensation phase is realized for arbitrary nonzero values of μI\mu_I. Contrary to this, for large values of μ>μc\mu>\mu_c, two CDW phases appear in the (μI,μ)(\mu_I,\mu)-phase diagram of the model. In the first phase, CDWs are clockwise twisted chiral spirals and in the second phase they are counterclockwise. The influence of nonzero temperature on the formation of the CDW phases is also investigated.Comment: 14 pages, 9 figures; typos corrected; one reference adde

    Thermal stability, sorption properties and morphology of films of dipeptide and tripeptide based on L-glycine

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    The effect of the number of amino acid residues in L-glycyl-L-glycine and L-glycyl-L-glycyl-L-glycine on thermal stability of powders, the sorption properties and surface morphology of thin films has been found. Dipeptide forms the film coated with disk-shaped nano-objects on the hydrophilic substrate, while tripeptide self-organizes to the film coated with nano-crystals on the hydrophobic substrate. Replacement of substrates (hydrophilic→hydrophobic) leads to the formation of smooth films of studied oligopeptides. Powders of oligopeptides do not form stable clathrates with water and organic compounds at room temperature. But their thin films are capable to bind organic or water vapors with high thermodynamic activity. Surprising difference in sorption selectivity of dipeptide and tripeptide has been observed. L-glycyl-L-glycine predominantly binds organic H-donors, while L-glycyl-L-glycyl-L-glycine is more selective to H-aceptors

    AFM study of thin films of oligopeptide L-valyl-L-valine before and after interaction with vapors

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    © 2016, Pleiades Publishing, Ltd.The effect of the substrate type, ambient relative humidity, water vapor and vapors of organic compounds on the surface morphology of films based on dipeptide L-valyl-L-valine are studied using atomicforce microscopy. It is found that at a low relative humidity the dipeptide is crystallized on a hydrophobic substrate with the formation of pyramidal structures, while at a high relative humidity hollow truncated cones are observed. A dipeptide film coated with irregularly shaped objects is observed on hydrophilic substrates. After saturation of the L-valyl-L-valine film with the vapors of proton-donor solvents the formation of new objects on its surface or the destruction of initial objects can occur, while water vapor does not affect the surface morphology. For proton acceptors the major factor affecting the surface morphology of dipeptide film is their energy of the hydrogen bond with proton donors. It is shown that the effect of organic vapors on the film morphology depends on the substrate type

    Interaction of l-alanyl-l-valine and l-valyl-l-alanine with organic vapors: Thermal stability of clathrates, sorption capacity and the change in the morphology of dipeptide films

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    © 2015 the Owner Societies. The strong effect of the amino acid sequence in l-alanyl-l-valine and l-valyl-l-alanine on their sorption properties toward organic compounds and water, and the thermal stability of the inclusion compounds of these dipeptides have been found. Generally, l-valyl-l-alanine has a greater sorption capacity for the studied compounds, but the thermal stability of the l-alanyl-l-valine clathrates is higher. Unusual selectivity of l-valyl-l-alanine for vapors of few chloroalkanes was observed. The correlation between the change in the surface morphology of thin film of dipeptides and stoichiometry of their clathrates with organic compounds was found. This discovery may be used to predict the influence of vapors on the morphology of films of short-chain oligopeptides

    Thermally induced diphenylalanine cyclization in solid phase

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    © 2016, Akadémiai Kiadó, Budapest, Hungary.The reaction of cyclization of diphenylalanine in solid phase under heating was studied, which is a stage in formation of various nanostructures from this dipeptide. The temperature ranges of the reaction as well as of dehydration of clathrate of diphenylalanine with water were determined. Kinetic parameters of cyclization were estimated within the approaches of the non-isothermal kinetics (“model-free” kinetics and linear regression methods for detection of topochemical equation). The product of diphenylalanine cyclization was characterized by X-ray powder diffractometry, FTIR spectroscopy and TG/DSC analysis. Crystallization of diphenylalanine and cyclo(diphenylalanine) from methanol solutions was studied using atomic force microscopy. The results obtained may be useful for the design of new nanomaterials based on diphenylalanine at high temperatures

    Assessment of the antifungal activity of the violacein-forming strain Janthinobacterium sp. B-3515 against the mould fungus Alternaria brassicicola F-1864

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    A study of antifungal properties of violacein-forming strain Janthinobacterium sp. B-3515 as well as its secondary metabolite, violacein, against Alternaria brassicicola F-1864 is presented. Regardless of the presence of bacteria, mycelium growth in the first two days proceeded at the same rate. The effect of the bacterial strain was manifested after the third day of incubation. In general, during co-culture, the bacterial strain statistically significantly reduced the average growth of the mycelium of the mould fungus by 10

    Complex-formation properties of orginal and generic fluoroquinolon drugs with respect to magnesium ions dependent of dissolution pH

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    The article deals with the influence of the dissolution medium’s pH value on the complexing properties of generic fluoroquinolones with respect to magnesium ions in vitro.В статье рассмотрено влияние значения pH среды растворения на комплексообразующие свойства воспроизведённых препаратов фторхинолонов по отношению к ионам магния in vitro

    Результаты игловой биопсии плевры в диагностике экссудативных плевритов

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    Summary. In this study, diagnostic value of pleural needle biopsy has been estimated. Biopsy specimens were obtained from 226 patients with pleural exudates of different etiologies. A high diagnostic sensitivity of this procedure was estimated under the lowest rate of complications. Резюме. Целью исследования являлось определение диагностической ценности игловой биопсии плевры (ИБП) при плевральной патологии. С марта 2006 по январь 2011 г. было выполнено 226 ИБП. Возраст пациентов, среди которых мужчин было 160 (70,8 %), женщин – 66 (29,2 %), варьировался от 18–84 лет. В 39,8 % случаев (у 90 больных) биопсия проводилась по поводу изолированного плеврита, в 60,2 % (у 136) – при плеврите, осложнившем основной процесс в легком или другом экстраторакальном органе. Проведенное исследование показало, что ИБП является высокоинформативным методом диагностики, а его чувствительность при выявлении туберкулезного плеврита составляет 70,2 %

    The experience of using epidural blood patch method for patients with spontaneous intracranial hypotension associated with appearance of cerebrospinal fluid leaks

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    The article presents analysis of evaluation of epidural blood patch method proficiency towards to treatment of spontaneous intracranial hypotension associated with appearance of cerebrospinal fluid (CSF) leaks. The analysis include 18 cases of applying this procedure in patient with verified CSF leaks, also there is the description of hte operation and clinical diagnostic criteria.В статье представлен анализ результатов оценки эффективности методики epidural blood patch в отношении лечения спонтанной ликворной гипотензии, развившейся на фоне наличия спинальных ликворных фистул. Проведен анализ 18 случаев применения методики epidural blood patch у пациентов с верифицированными ликворными фистулами, представлено описание методики, а также основные клинические критерии постановки диагноза
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