769 research outputs found

    Properties of dwarf stars in Cygnus OB2

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    We present the results of investigation of five stars, originally classified as dwarfs, belonging to Cyg OB2 association, their stellar and wind properties. Using both TLUSTY and CMFGEN codes we derived effective temperatures, surface gravities, chemical abundances, mass-loss rates and projected rotation velocities. Due to the fact that distance to the stars is well known, we were able to estimate their luminosities. Using evolutionary models we estimated the ages of these sample stars and find that lower mass ones - MT282 and MT343 - belong to older population of the association. Their ages are greater than 10 Myr. The ages of three other stars - MT317, MT299, MT259 - are between 4-6 Myr.Comment: 16 pages, 10 figures, accepted for publication in PAS

    Thermoelectric performance of weakly coupled granular materials

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    We study thermoelectric properties of inhomogeneous nanogranular materials for weak tunneling conductance between the grains, g_t < 1. We calculate the thermopower and figure of merit taking into account the shift of the chemical potential and the asymmetry of the density of states in the vicinity of the Fermi surface. We show that the weak coupling between the grains leads to a high thermopower and low thermal conductivity resulting in relatively high values of the figure of merit on the order of one. We estimate the temperature at which the figure of merit has its maximum value for two- and three-dimensional samples. Our results are applicable for many emerging materials, including artificially self-assembled nanoparticle arrays.Comment: 4 pages, 3 figure

    Regression in the Symptoms and Discal Hernia in Case of Lumbar Radiculopathy

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    BACKGROUND: Discogenic lumbar radiculopathy has a favorable potential for survival; the regression of clinical symptoms may outpace the subsidence of discal hernia. AIM: The objective of the study is comparing the clinical data and the results of magnetic resonance imaging (MRI) in patients with discogenic lumbar radiculopathy over 1 year of observation. MATERIALS AND METHODS: Thirty-two patients (13 males at the average age of 39.1 ± 11.8 years) with discogenic lumbar radiculopathy confirmed by MRI were examined in the study. The intensity of pain condition was assessed using the numerical rating scale; disability was assessed using the Oswestry disability index. Sixteen patients were subjected to repeated MRI. RESULTS: Statistically significant (p &lt; 0.01) reduction of the average pain intensity and intensity of disability more than 2 times was observed as early as in the first 2 weeks. Gradual reduction of pain and disability was observed during the year. Reduction of discal hernia by more than 50% was observed on average after 8.7 ± 4.7 months. CONCLUSION: In the case of discogenic radiculopathy, the reduction of pain and related disability far outstrips the regression of the herniation of intervertebral disk

    Outpatient management of patients with dyscirculatory encephalopathy

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    There is outpatient hyperdiagnosis of dyscirculatory encephalopathy (DE) frequently masked by other diseases. Objective: to improve the differential diagnosis of DE on the basis of a comprehensive patient examination, including neuropsychological testing. Patients and methods. Fifty patients, including 10 men and 40 women, aged 45 to 75 years (mean age 68.8±9.0 years), who had been followed up at the polyclinic with a diagnosis of DE for an average of 1.5 years, were examined. All the patients underwent evaluations of cognitive functions and emotional status and otoneurological examination (in case of headache); a psychiatrist consulted patients with anxiety and/or depressive disorders. Results and discussion. Only 9 (18%) patients were found to have vascular cognitive impairments (CIs) and signs of cerebrovascular lesions, as shown by neuroimaging, which may be regarded as DE. Five (10%) patients had CIs and neuroimaging changes that were more characteristic of Alzheimer’s disease (AD) than those of DE. The remaining 36 (72%) patients were established to have other diseases (primary headache, peripheral vestibulopathy, primary anxiety and depressive disorders, etc.), in which CIs were not detected. The diagnosis and effective treatment of these diseases yielded a rapid positive result in most cases. The management of patients with DE and AD was aimed at preventing stroke and improving cognitive functions; moreover, akatinol memantine was noted to be effective in the combination therapy of both DE and AD

    Treatment for chronic daily headache by using auxiliary and alternative methods

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    Chronic daily headache (CDH) is one of the top 10 causes of adult disability and one of the 5 most common causes of female disability. To treat patients with CDH is one of the most difficult tasks in neurological practice. Difficulties in managing patients with CHD are associated with the high prevalence of comorbid mental disorders, analgesic abuse, pain syndromes at another site, and misconceptions of a patient about his/her disease. A combination of drug and non-drug therapies is the mainstay of the current approach to treating patients with CDH. Standard, alternative, and auxiliary therapies are identified. The paper describes different types of current auxiliary and alternative therapy used in the world’s leading headache centers and clinics. It describes experience with cerebrolysin used as auxiliary and alternative pharmacotherapies for CDH

    Management of patients with neck pain

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    Neck pain (cervicalgia) occupies one of the leading places among the reasons for outpatient visits, 75% of people have experienced neck pain at least once in their lives. In most cases, neck pain regresses; however, it recurs in almost one half of patients. The paper gives data on the risk factors, mechanisms, course, and prognosis of cervicalgia. It discusses the issues of differential diagnosis, examination, and approaches to treating this condition in these patients. Nonsteroidal anti-inflammatory drugs are most effective in treating patients with acute cervicalgia. Therapeutic exercises and manual therapy are indicated in patients with chronic cervicalgia. There is evidence on the efficacy and safety of meloxicam for the management of acute and chronic cervicalgia
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