107 research outputs found

    Spatial Distribution of Chemical and Organic Compounds in the Water of Oligotrophic Peatland of Tomsk Region (Western Siberia)

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    In the central part of Western Siberia a study of the chemical and organic compounds spatial distribution in the water of oligotrophic peatland has been carried out. It was shown that marsh water generally contains exceptionally low total dissolved salinity (TDS), low pH value, high content of organic matter and NH4, increased content of Fe. The composition of organic matter is characterized by pronounced predominance of organic compounds and the presence of hydrocarbon and oxygen-containing compounds. Features of ionic and organic distribution in water and its ground were investigated

    Scanning-probe spectroscopy of semiconductor donor molecules

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    Semiconductor devices continue to press into the nanoscale regime, and new applications have emerged for which the quantum properties of dopant atoms act as the functional part of the device, underscoring the necessity to probe the quantum structure of small numbers of dopant atoms in semiconductors[1-3]. Although dopant properties are well-understood with respect to bulk semiconductors, new questions arise in nanosystems. For example, the quantum energy levels of dopants will be affected by the proximity of nanometer-scale electrodes. Moreover, because shallow donors and acceptors are analogous to hydrogen atoms, experiments on small numbers of dopants have the potential to be a testing ground for fundamental questions of atomic and molecular physics, such as the maximum negative ionization of a molecule with a given number of positive ions[4,5]. Electron tunneling spectroscopy through isolated dopants has been observed in transport studies[6,7]. In addition, Geim and coworkers identified resonances due to two closely spaced donors, effectively forming donor molecules[8]. Here we present capacitance spectroscopy measurements of silicon donors in a gallium-arsenide heterostructure using a scanning probe technique[9,10]. In contrast to the work of Geim et al., our data show discernible peaks attributed to successive electrons entering the molecules. Hence this work represents the first addition spectrum measurement of dopant molecules. More generally, to the best of our knowledge, this study is the first example of single-electron capacitance spectroscopy performed directly with a scanning probe tip[9].Comment: In press, Nature Physics. Original manuscript posted here; 16 pages, 3 figures, 5 supplementary figure

    Peripheral blood T helper cell subsets in Löfgren’s and non-Löfgren’s syndrome patients

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    Sarcoidosis is a multisystemic granulomatous disorder of unknown cause, characterized by formation of immune granulomas in various organs, mainly in lungs. Currently, two main phenotypes of pulmonary sarcoidosis are described, i.e., Lofgren’s syndrome (LS) is an acute form with favorable outcome, and non-Lofgren’s syndrome (nLS) is a chronic type of disease with a high risk of pulmonary fibrosis. Our study was aimed to investigate the balance of main “polarized” CD4+ central and effector memory T cells from treatment-naive patients with pulmonary sarcoidosis (LS (n = 19) and nLS (n = 63)) compared to healthy volunteers (HC, n = 48). This marker might be used as immunological markers for predicting severity of this disorder. Multicolor flow cytometry analysis demonstrated that the patients with nLS showed significantly low levels of relative and absolute numbers of CD3+CD4+ lymphocytes if compared to patients with LS and control group (38.94% (31.33-44.24) versus 48.96% (43.34-53.54) and 47.63% (43.82-52.73), p < 0.001 in both cases). Moreover, patients with nLS had reduced frequencies and absolute numbers of “naive”, CM and EM Th cells if compared with healthy controls. Furthermore, the patients with LS showed increased relative and absolute numbers of peripheral blood EM Th cells, capable for migration to peripheral inflamed tissues, when compared with nLS. Finally, patients with LS had increased frequencies and absolute numbers of effector TEMRA Th cells as compared to HC and nLS. Next, significant differences Th1 and Th2 cells frequencies were shown between the patients with nLS and HC (9.64% (7.06-13.65) versus 13.80% (11.24-18.03) with p < 0.001, and 11.96% (9.86-14.78) versus 10.67% (9.13-12.98) with p = 0.048, respectively). But there were no significant differences in the relative numbers of CXCR5-CCR6+Th17 and CXCR5+ follicular T helper cells (Tfh) between the groups. Finally, both groups of patients with pulmonary sarcoidosis contained low proportions of “non-classical” Th17 and DN Th17 cell, but increased levels of DP Th17 cells within total CXCR5-CCR6+ CM Th if compared with HC. Nevertheless, patients with nLS had increased frequency of “classical” Th17 in comparison with healthy controls. A very similar imbalance between different Th17 cell subsets was observed within total CXCR5CCR6+ effector memory Th, that were able to migrate from the bloodstream to the sites of infection, or tissue injury. Taken together, the data suggest that the proportions of Th17 cell subsets in pulmonary sarcoidosis can be evaluated as a diagnostic and/or prognostic marker in clinical practice and these cells could serve as a new therapeutic target

    Peripheral blood B cell subsets from patients with various activity of chronic sarcoidosis

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    Sarcoidosis is an inflammatory disease of unknown etiology, characterized by development of necrosis-free epithelioid cell granulomas, resulting in hyperactivation of various cells of the immune system. The role of humoral mechanisms in the pathogenesis of sarcoidosis is less studied than cell-mediated. It is necessary to study the role of activation or the anergy of the B cell development of immunity in sarcoidosis, the degree of its activity and the characteristics of the clinical course of the disease. Our study was aimed at investigating the characteristics of the B cells subsets in the peripheral blood of patients with chronic sarcoidosis (n = 41), depending on the activity of the disease. The control was peripheral blood samples from healthy volunteers (n = 43). Objective clinical and instrumental criteria, angiotensin converting enzyme (ACE) were used to determine the activity of the disease. Using flow cytometry analysis of peripheral blood cell B cells were determined based on two approaches: expression of IgD/CD38 (“Bm1-Bm5” classification) and IgD/CD27. In patients with sarcoidosis there was a significantly higher relative number of Bm2 "activated" naive cells" (IgD+CD38+) than in conditionally healthy volunteers, 65.38% versus 55,66% (p < 0.001). The relative and absolute contents of eBm5 (IgD-CD38+) and Bm5 (IgD-CD38+) memory cells were significantly lower in the group of patients with sarcoidosis relative to the control group. Relative values: 6.59% versus 13.31%, (p < 0.001), and 3.43% versus 8.49%, (p < 0.001), respectively. It was shown that with an increased level of ACE in the peripheral blood of patients, the number of naive Bm1 cells (IgD+CD38-) was significantly reduced, r = -0.557, p < 0.001. The relative content of memory B cells that did not switch the class of synthesized antibodies (IgD+CD27+) in the group of patients was reduced to 6,25%, and in the control group — 12,95% (p<0.001). The number of memory cells that switched the class of synthesized antibodies (IgD-CD27+) was also significantly reduced in patients with sarcoidosis and amounted to 6.75% versus 16.50% in the control group (p < 0.001). In patients with high levels of ACE, there was an increase in the relative content of naive B cells (IgD+CD27-), r = 0.532, p < 0.001. An inverse relationship was established between the number of memory B cells (IgD+CD27+) and ACE levels, r = -0.565, p < 0.001. These results indicate the important role of the B cell immune response in the pathogenesis of sarcoidosis and make it possible to evaluate the characteristics of the humoral response with various degrees of disease activity

    MHD models of Pulsar Wind Nebulae

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    Pulsar Wind Nebulae (PWNe) are bubbles or relativistic plasma that form when the pulsar wind is confined by the SNR or the ISM. Recent observations have shown a richness of emission features that has driven a renewed interest in the theoretical modeling of these objects. In recent years a MHD paradigm has been developed, capable of reproducing almost all of the observed properties of PWNe, shedding new light on many old issues. Given that PWNe are perhaps the nearest systems where processes related to relativistic dynamics can be investigated with high accuracy, a reliable model of their behavior is paramount for a correct understanding of high energy astrophysics in general. I will review the present status of MHD models: what are the key ingredients, their successes, and open questions that still need further investigation.Comment: 18 pages, 5 figures, Invited Review, Proceedings of the "ICREA Workshop on The High-Energy Emission from Pulsars and their Systems", Sant Cugat, Spain, April 12-16, 201

    Sarcoidosis clinical picture governs alterations in type 17 T helper cell subset composition and cytokine profile

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    Immune cell hyperactivation along with cytokines they overproduce plays an important role in sarcoidosis and related disease pathogenesis. A central place in the immunopathogenesis of sarcoidosis is held by diverse cell-mediated reactions governed by T helper (Th) cell populations including Th17 subsets and relevant signature cytokines. We studied peripheral blood plasma samples of the patients with sarcoidosis (n = 123): 18% with acute and 82% with chronic course. The control group — samples from healthy volunteers (n = 43). T cell subset composition was assessed by flow cytometry. Cytokine concentrations (pg/mL) were measured by multiplex analysis using xMAP technology (Luminex). The level of “classical” Th17 turned out to be significantly reduced in acute vs chronic sarcoidosis: 28.3% vs 33.3% (p = 0.046). The level of “double-positive” Th17 (DP Th17) was significantly increased in chronic and acute vs control group: 31.7% and 34.2% vs 26.2% (p < 0.001 in both cases), without differences patient inter-group; “non-classical” Th17.1 were shown to have significantly reduced level only in chronic vs healthy subjects: 27.9% and 35.9% (p < 0.001). Clinical and laboratory diagnostic characteristics for blood DP Th17 levels in CD45RA-negative Th effector memory cells in sarcoidosis: in acute sarcoidosis vs healthy subjects, they were characterized by sensitivity — 82%; specificity — 71%, whereas in chronic: 67% and 56%, respectively. In patients with sarcoidosis vs healthy subjects were found to have significantly increased level of IL-12 (p70) — 1.3 vs 0.56, p = 0.028; IL-17A — 1.5 vs 0.43, p < 0.001; IFNγ — 4.1 vs 1.1, p < 0.001; TNFα — 21.7 vs 6.7, p < 0.001. Thus, CCR6+ Th17 and DP Th17 subsets and relevant signature cytokines are important in diagnostics of sarcoidosis of varying clinical course: a direct correlation was shown between the level of angiotensin-converting enzyme activity and percentage of memory DP Th17; disease progression vs regression had significantly reduced absolute number of total CD45RA- memory and CM Th17; extrapulmonary manifestations had a significantly increased percentage of DP Th17 CD45RA- and EM DP Th17; in chronic sarcoidosis are significantly increased concentration of IL-17A, IFNγ, IL-12 and positively correlation between IFNγ and the activity of angiotensin-converting enzyme

    Regulation of the vapBC-1 Toxin-Antitoxin Locus in Nontypeable Haemophilus influenzae

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    Nontypeable Haemophilus influenzae (NTHi) are human-adapted commensal bacteria that can cause a number of chronic mucosal infections, including otitis media and bronchitis. One way for these organisms to survive antibiotic therapy and cause recurrent disease is to stop replicating, as most antimicrobials target essential biosynthetic pathways. Toxin-antitoxin (TA) gene pairs have been shown to facilitate entry into a reversible bacteriostatic state. Characteristically, these operons encode a protein toxin and an antitoxin that associate following translation to form a nontoxic complex, which then binds to and regulates the cognate TA promoter. Under stressful conditions, the labile antitoxin is degraded and the complex disintegrates, freeing the stable toxin to facilitate growth arrest. How these events affected the regulation of the TA locus, as well as how the transcription of the operon was subsequently returned to its normal state upon resumption of growth, was not fully understood. Here we show that expression of the NTHi vapBC-1 TA locus is repressed by a complex of VapB-1 and VapC-1 under conditions favorable for growth, and activated by the global transactivator Factor for Inversion Stimulation (Fis) upon nutrient upshift from stationary phase. Further, we demonstrate for the first time that the VapC-1 toxin alone can bind to its cognate TA locus control region and that the presence of VapB-1 directs the binding of the VapBC-1 complex in the transcriptional regulation of vapBC-1

    Epidemiologic approaches to assessing human cancer risk from consuming aquatic food resources from chemically contaminated water.

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    Epidemiologic approaches to assessing human cancer risk from consuming fish from contaminated waters must confront the problems of long latency and rarity of the end point (cancer). The latency problem makes determination of diet history more difficult, while the low frequency of cancer as an end point reduces the statistical power of the study. These factors are discussed in relation to the study designs most commonly employed in epidemiology. It is suggested that the use of biomarkers for persistent chemicals may be useful to mitigate the difficulty of determining exposure, while the use of more prevalent and timely end points, such as carcinogen-DNA adducts or oncogene proteins, may make the latency and rarity problems more tractable

    Эффективность терапии N-ацетилцистеином (Флуимуцил Zambón Group) бронхообсруктивного синдрома при муковисцидоз

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    This article demonstrates high clinical efficacy of long-term treatment of bronchial obstructive syndrome in cystic fibrosis (CF) patients with N-acetylcysteine (Fluimucil, Zambon Group). Lung function parameters, oxygen saturation, sputum viscosity, biochemical parameters of inflammation activity in sputum (elastase, sialic acid and α1-antitripsin concentrations) were evaluated. Oral Fliumucil was combined with inhaled N-acetyl-Lcysteine. The therapy resulted in reduction of the sputum viscosity, recovering of the mucociliary clearance, improvement in the lung function, antiinflammatory and antioxidative effects of Fliumucil. This allows to recommend the drug for the long-term basic therapy of bronchoobstructive syndrome in CF patients.В статье показана высокая эффективность длительной терапии N-ацетилцистеином (флуимуцил, "Zambon Group") при лечении бронхообструктивного синдрома у больных муковисцидозом. Оценивались функциональное состояние легких, сатурация кислорода, вязкоэластические свойства мокроты; биохимические показатели активности воспалительного процесса в бронхиальном секрете (концентрация эластазы, сиаловых кислот, α1-антитрипсина). Прием флуимуцила внутрь сочетали с назначением ингаляций N-ацетил-L-цистеина. Показана нормализация вязкоэластических свойств мокроты, восстановление мукоцилиарного клиренса, улучшение дыхательной функции, противовоспалительное и антиоксидантное действие флуимуцила, что позволяет рекомендовать препарат для длительной базисной терапии бронхообструктивного синдрома у больных муковисцидозом
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