249 research outputs found
On the Thermal Instability in a Contracting Gas Cloud and Formation of a Bound Cluster
We perform linear analysis of thermal instability in a contracting large
cloud filled with warm HI gas and investigate the effect of metallicity and
radiation flux. When the cloud reaches critical density n_f, the cloud
fragments into cool, dense condensations because of thermal instability. For a
lower metallicity gas cloud, the value of n_f is high. Collision between
condensations will produce self-gravitating clumps and stars thereafter. From
the result of calculation, we suggest that high star formation efficiency and
bound cluster formation are realized in low-metallicity and/or strong-radiation
environments.Comment: 7 pages, including 7 figures, LaTeX2e(emulateapj5.sty) To appear in
ApJ, Jun 10, 200
Nonwoven PTFE Membranes Fabricated by Electrospinning Method: Preparation and Characterization
Polytetrafluoroethylene (PTFE) is one of the promising materials for the purposes of tissue engineering and chemical technology because of its excellent physico-chemical properties and mechanical characteristics. However, conventional methods of PTFE porous membranes production have several disadvantages which limit the number of potential application areas by reason of a insufficient surface-to-volume ratio and poor porosity at small thickness. In the paper the results of using PTFE water suspension with a solution of water-soluble polymer for preparation of porous membranes by electrospinning are reported. The physico-chemical characteristics of membranes were investigated depending on the content of PTFE dispersion in spinning solution. There were found high hydrophobicity and lyophilicity of PTFE electrospun membranes. Main reasons of poor mechanical properties of porous membranes at high content of PTFE suspension in spinning solution are discovered. The ways of mechanical properties improvement and areas of possible applications are proposed
Link of apoptosis level in the primary tumor at early stages of non-small cell lung cancer with efficacy of adjuvant polychemotherapy.
One of the important questions in modern oncology is treatment of patients with early stages of non-small cell lung cancer (NSCLC). Adjuvant polychemotherapy (APCT) can help to improve prognosis after operation. In modern literature there is no unified opinion as for patients in need of adjuvant chemotherapy. However, now investigators indicate to necessity to use molecular markers for individualization of APCT. The aim of our study was to assess correlation between apoptos level in primary tumor in patients with early stages of NSCLC with effectiveness of APCT. Study was conducted by the chair of oncology of Zaporozhye state medical university since June 2008 to Dec 2012. 254 patients with I-II stages of non-small cell lung cancer were included in the study. Expression of p53 was evaluated as percent of positively stained nucleus tumor cells in general population. More than 25% of positively stained nucleus tumor cells meant high p53 expression. Results: We performed assessment of apoptosis level with the help of p53 expression in 220 patients. No prognostic significance of p53 level expression in patients with early stages of non-small cell lung cancer (р=0,65) was revealed. There was significant correlation between age (р=0,039), sex (р=0,009) and apoptosis level in primary tumor in patients with early stages of NSCLC. Worse survival was noted in group of patients with low p53 expressions after adjuvant chemotherapy (р=0,009). But in patients with high level of p53 expression adjuvant chemotherapy significantly increased survival (p<0,001). So, adjuvant chemotherapy in patients with I-II stages of NSCLC is necessary to be carried out in cases of high p53 expression level
Pathogenetic aspects of retroviral infections
Bovine leukemia and equine infectious anemia are registered in most regions of Ukraine and in many countries worldwide. This is accompanied by economic losses and reduced quality of livestock products, which determines the relevance of the study of retroviral infections, their diagnosis, and pathogenesis. The goal of our research was to find and improve the methodological foundations of the development of the pathological process for a more in-depth study of the etiology, pathogenesis, treatment, and prevention of retroviral infections. The object of the study was blood, lymph nodes, spleen, heart, lungs, liver, and kidneys for bovine leukemia and equine infectious anemia. Hematological, anatomical, histological, histochemical, morphometric, and statistical research methods were used for their study. The research group included 304 cattle aged 4–9 years and 42 horses, of which 25 were infected with the virus, and 17 were in the control group. It has been established that bovine leukemia and infectious anemia of horses is an irreversible pathological process characterized by slow progression, the presence of a latent or persistent form, with damage to cells, organs, and systems of the body, which leads to death. Infectious anemia of horses differs from leukemia of cattle by the hidden course of the pathological process. The pathogenesis of leukemia occurs in six stages, which we have identified and conventionally named
Clinical case of chemoresistant tuberculosis in the patient with tuberous sclerosis: difficulties of diagnosis, features of the course and treatment.
In the practical activities of a modern doctor, significant difficulties are noted in the diagnostics and proper management of patients with hereditary diseases due to the limited coverage of the population by genetic researches. For a long time, the patients with a variety of complaints are observed by doctors of various specialties, and the therapy often has little effect due to a lack of understanding of the true causes of pathological changes. The situation is complicated by case of a combined course of a hereditarily caused disease and some other disease of an infectious, non-infectious or tumor nature. The aim of the research was to study the characteristics of clinical manifestations, course of tuberculosis with resistance to anti-TB drugs in a patient with a rare hereditary disease from the group of phacomotoses - Bourneville-Pringle disease or tuberous sclerosis. This disease has a wide range of clinical manifestations, accompanied with the development of benign neoplasms in various organs and systems, damages to the skin, brain, organs of vision, lungs, kidneys, heart, as well as the musculoskeletal and endocrine system. It leads to development of various infectious and non-infectious pathologies in these organs. The article covers a 4-year period of observation of a young patient with late diagnosed tuberous sclerosis, suffering from pulmonary tuberculosis and tuberculosis of urinary system, includes the initial diagnosis of a specific disease, the course, the dynamics against received treatment and the development of relapse with the formation of resistance to anti-TB drugs. The difficulties in the management of tuberculosis in this patient were in the detection of numerous neoplasms and changes in the internal organs, in particular in the kidneys and lungs, which characterized tuberous sclerosis, on the one hand this contributed to untimely diagnosis of tuberculosis, and on the other hand – worsening the course and the progression of a specific process, as well as an unfavourable prognosis for recovery
Prognosis of recurrent myocardial infarction based on shortliffe fuzzy models using the electrical characteristics of biologically active points
This report discusses the employment of the electrical characteristics of biologically active points (BAP) in the meridian of the heart to solve the task of prognosticating recurrence of myocardial infarctions during the rehabilitation period using fuzzy decision rule
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