238 research outputs found

    Protein Dynamics Control of Electron Transfer in Photosynthetic Reaction Centers from Rps. Sulfoviridis

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    In the cycle of photosynthetic reaction centers, the initially oxidized special pair of bacteriochlorophyll molecules is subsequently reduced by an electron transferred over a chain of four hemes of the complex. Here, we examine the kinetics of electron transfer between the proximal heme c-559 of the chain and the oxidized special pair in the reaction center from Rps. sulfoviridis in the range of temperatures from 294 to 40 K. The experimental data were obtained for three redox states of the reaction center, in which one, two, or three nearest hemes of the chain are reduced prior to special pair oxidation. The experimental kinetic data are analyzed in terms of a Sumi–Marcus-type model developed in our previous paper,1 in which similar measurements were reported on the reaction centers from Rps. viridis. The model allows us to establish a connection between the observed nonexponential electron-transfer kinetics and the local structural relaxation dynamics of the reaction center protein on the microsecond time scale. The activation energy for relaxation dynamics of the protein medium has been found to be around 0.1 eV for all three redox states, which is in contrast to a value around 0.4–0.6 eV in Rps. viridis.1 The possible nature of the difference between the reaction centers from Rps. viridis and Rps. sulfoviridis, which are believed to be very similar, is discussed. The role of the protein glass transition at low temperatures and that of internal water molecules in the process are analyzed.España, Ministerio de Educación y Ciencia BFU2004-04914-C02-01/BMCJunta de Andalucía PAI CVI-26

    Strongly localized polaritons in an array of trapped two-level atoms interacting with a light field

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    We propose a new type of spatially periodic structure, i.e. polaritonic crystal (PolC), to observe a "slow"/"stopped" light phenomenon due to coupled atom-field states (polaritons) in a lattice. Under the tightbinding approximation, such a system realizes an array of weakly coupled trapped two-component atomic ensembles interacting with optical field in a tunnel-coupled one dimensional cavity array. We have shown that the phase transition to the superfluid Bardeen-Cooper-Schrieffer state, a so-called (BCS)-type state of low branch polaritons, occurs under the strong coupling condition. Such a transition results in the appearance of a macroscopic polarization of the atomic medium at non-zero frequency. The principal result is that the group velocity of polaritons depends essentially on the order parameter of the system, i.e. on the average photon number in the cavity array.Comment: 16 pages, 6 figure

    NOVEL APPROACHES TO TREATING NONSPECIFIC LOW BACK PAIN

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    Objective: to evaluate the impact of therapy with chondroitin sulfate (CS) and glucosamine (GA) on the clinical manifestations of low back pain (LBP).Subjects and methods. A multicenter open-label observational prospective study was conducted in 22 cities of Russia (46 centers) to investigate the efficacy of a combination of CS and GA in the outpatient treatment of nonspecific LBP. A total of 9761 patients were enrolled in the study that was completed by 8546 patients. Therapeutic efficiency was evaluated from changes in pain intensity during movement and at rest, by using the visual analogue scale. The Oswestry disability index, an global physician and patient assessment of therapeutic efficiency, and a daily need for nonsteroidal anti-inflammatory drugs (NSAIDs) were taken into account as additional criteria for efficiency evaluation.Results and discussion. The multicenter open-label observational study established the efficacy of a combination of CS and GA in treating nonspecific LBP: relief in pain during movement and at rest, functional improvement, and a reduction in the daily need for NSAIDs. The patients and physicians highly assessed therapeutic efficiency. The combination of CS and GA was also noted to be well tolerated. The findings may suggest that this combination may be a promising tool to treat LBP and gives proof to the expediency of its use in randomized placebo-controlled studies

    IMMUNOLOGIC MARKER OF INTRANATAL INFECTIONS

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    The results of the research established determination of immunologic marker for prognosis of intranatal infection. The authors performed a comparative study of the immunity values of women in a risk group for prenatal infection. As it was shown when prenatal infection develops, there is an increase in the content of proinflammatory cytokines in the pregnant woman serum and activation of the ingestion rate. Account the results to devise an algorithm the pregnant woman care

    5-YEAR SURVIVAL OF PATIENTS WITH STAGE II UTERINE CANCER DEPENDING ON MORPHOLOGIC FEATURES OF TUMOR

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    Retrospective data of treatment results of 109 patients with rarely observed stage II uterine cancer, admitted to N.N. Blokhin Russian Cancer Research Center from 1980 to 2000 is analyzed. Correlation of overall 5-year survival rates of stage IIA and IIB uterine can- cer patients with a number of tumor morphologic features is studied. The influence of some non-elucidated morphologic features of stage IIA and IIB uterine cancer such as the degree of cellular anaplasia, the depth of tumor invasion into the uterine neck, lymho- vascular invasion into the myometrium and uterine neck, microscopic vessels density in the area of the most extensive invasion, the presence of necrotic areas in the tumor tissue on long-term treatment results are analyzed

    CLINICAL CHARACTERISTICS OF OVARIAN CLEAR CELL CANCER

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    The research has enrolled 96 patients with rare ovarian clear cell cancer treated at N.N. Blokhin Russian Cancer Research Center from 1978 to 2000. A necessity to divide patients into two groups has emerged after histopathological slide review. The first group included 71 patients with ovarian clear cell carcinoma (OCCC). Twenty five patients with mixed malignant epithelial ovarian tumor (MMEOT) with mandatory presence of clear cell component were included into the second group. Clinical par- ticularities of clear cell ovarian cancer were studied. We performed a comparative study of clinical course of OCCC and MMEOT. Our data suggest that clear cell ovarian cancer has a number of typical clinical and biological particularities both in OCCC and MMEOT

    The role of obstetric pessary and micronized progesteron in early preterm birth prevention in patients with multiple pregnancy

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    Background. Multiple pregnancy is a well-established risk factor for preterm birth. Prevention of early termination of pregnancy is a priority problem in obstetric practice.The aim. To evaluate the role of an obstetric pessary and micronized progesterone in the prevention of early preterm labor in patients with multiple pregnancies.Materials and methods. A prospective controlled study was conducted with the inclusion of 146 pregnant women with multiple pregnancies, which, depending on the methods of treatment, were divided into three groups: Group I (n = 67) – pregnant women who received micronized progesterone in combination with an obstetric pessary; Group II (n = 57) included women who received micronized progesterone; Group III (n = 22) consisted of patients with multiple pregnancies without therapy.Results. In Group I, the complex of an obstetric pessary and micronized progesterone allowed to reduce the frequency of preterm birth by 2.3 times (p = 0.008) in comparison with Group III, the frequency of births at gestational age ≤ 34 weeks – by 8.1 times (p = 0.005) in compared with Group III and 2.7 times (p < 0.01) compared with Group II. In 70.4 % of pregnant women, the use of a complex of an obstetric pessary with micronized progesterone made it possible to prevent the formation of isthmiccervical insufficiency, which, according to sonography, was expressed in the dynamics of the utero-cervical angle towards a more obtuse one.Conclusion. The use of an obstetric pessary with micronized progesterone made it possible to reduce the risks of isthmic-cervical insufficiency by 7.7 % compared with patients who received only micronized progesterone therapy, and by 17.1 % compared with pregnant women who did not receive therapy

    Archaeological sites as markers of Neopleistocene-Holocene hydrological system transformation in the Kurai and Chuya basins, Southeastern Altai: Results of geomorphological and geoarchaeological studies

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    Multidisciplinary studies using geomorphological, geoarchaeological, and geochronological approaches indicate contrasting environmental changes in Southeastern Altai, beginning in the Late Pleistocene. 29 new radiocarbon dates from the subaerial complex overlying Late Neopleistocene sediments in the high-altitude Kurai and Chuya basins confirm the degradation of a single ice-dammed reservoir in that area before the Early Holocene. In the first half of the Holocene, those basins were filled with isolated lakes. At the mouth of the Baratal River in the western Kurai basin, a reservoir with a water-level of at least 1480 m a.s.l. emerged ca 10–6.5 ka cal BP; whereas in the Chuya depression, numerous residual lakes existed at least 8 ka cal BP. Landslide- and moraine-dammed lakes between the depressions in the Chuya River valley existed until 7–3 ka cal BP, when they drained away. The state of preservation of in situ archaeological sites, their cultural affiliation, and their locations within the depressions and along the main Chuya valley attest to spatial and temporal changes in the hydrological system. This evolution in the second half of the Holocene did not entail major consequences for humans. All cataclysmic flood events took place (occurred) before 10–8 ka cal BP. © 2016 A.R. Agatova, R.K. Nepop, I.Y. Slyusarenko, V.S. Myglan, V.V. Barinov.Geomorphological studies, including radiocarbon dating, were supported by the Russian Foundation for Basic Research (Projects No. 15-05-06028 and 16-05-01035); archaeological and dendrochronological studies were supported by the Russian Science Foundation (Projects No. 14-50-00036 and 15-14-30011 respectively)

    Why a pregnant age can be the risk factor in chronic obstructive pyelonephritis?

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    The aim of the study was to identify possible mechanisms that could reproduce the recurrence of CVD in older men against the background of non-steroidal anti-inflammatory drugs and antibiotics, thereby justifying why age and sex may be risk factors for acute pyelonephritis in urolithiasis. Material and methods. The results of a study of 88 men with chronic obstructive pulmonary disease, including 45 patients over 65 years of age (mean age 74.0 ± 1.3 years) and 43 patients in the age range of 55-65 years (mean age of patients 61.0 ± 0, 8 year). In the phase of remission of CVD, 48 patients were examined and in the phase of relapse-40 patients. The study included patients who took non-steroidal anti-inflammatory drugs (NSAIDs) and antibiotics in a standard dose of at least 5-10 days before hospitalization. From the peripheral blood by centrifugation, plasma-enriched plasma was isolated. Platelet content in 1 μl was 200,000 ± 20,000. To stimulate platelets, adrenaline and ADP (Sigma, USA) were used at an effective concentration (EC50) of 5 μM, which caused platelet aggregation (ATC) in healthy individuals (10 donors) at the level of 50 ± 5%. The aggregation of Tc was evaluated on a Chrono log analyzer (USA). The formation of platelet-leukocyte aggregates (TPA) was modeled in vitro by incubation of stimulated platelets (epinephrine at a concentration of EC50) and intact leukocytes isolated from the peripheral blood of patients with CVD. The number of intact TL was assessed after the color of blood smears according to the Romanovsky-Giemsa method. Results. In the phase of remission of CVD on the background of the appointment of NSAIDs and antibiotics, in patients of the two age groups studied, it was not possible to detect differences in the response of leukocytes. Recurrence of CVD in patients age range 55-65 years was characterized by leukocytosis, neutrophilocytosis, increased ESR (
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