182 research outputs found

    Action of a heat source and influence of initial condition on the plane state of temperature

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    The work takes an advantage of the temperature component method for some heat conduction problems. Simplifications of the method for 2D problems are considered. Some examples of calculations are quoted

    Hybrid Material Based on the Lindquist Polyoxometalate [W6O19]2− and the organosulfur donor o-Me2TTF: A Combined Structural and Spectroscopic Study

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    International audienceThe synthesis, crystal structure and spectroscopic properties of the hybrid radical cation salt containing oxidized o-3,4-dimethyltetrathiafulvalene (o-Me2TTF) and the Lindquist polyoxometalate anion [W6O19]2− are reported. The title salt represents the first time a Lindquist polyoxometalate has been utilized as the counter anion with this unsymmetrical member of the TTF family of derivatives. The salt crystallizes in the triclinic space group P1¯ with a = 7.6211(7) Å, b = 9.5231(9) Å, c = 12.2148(11) Å, α = 105.5870(10)°, β = 106.8340(10)° and γ = 95.6950(10)°. Resolution of the solid state structure revealed that the o-Me2TTF radical cations aggregate as isolated face-to-face dimers with intradimer interactions between neighboring sulfur atoms at distances <3.6 Å. Hydrogen bonding was also observed between hydrogen atoms bound to sp 2-hybridized carbon atoms of o-Me2TTF and bridging oxygen atoms of [W6O19]2−. Single crystal IR and Raman spectra were also collected and provide further evidence that the o-Me2TTF donors have been oxidized to their corresponding radical cationic states

    Leczenie chirurgiczne objawowych) naczyniaków kręgosłupa

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    Background and purpose Vertebral haemangiomas are relatively common, benign vascular lesions; symptomatic ones that cause spinal cord compression are rare, however. Only 0.9–1.2% of all vertebral haemangiomas are symptomatic. The aim of the paper is to present indications, operative techniques and stabilization methods in patients with symptomatic vertebral haemangiomas. Material and methods Clinical analysis included 7 patients treated between 1995 and 2007. There were 4 females and 3 males, aged 24 to 63 yrs (average age 44 yrs). Symptomatic vertebral haemangiomas were diagnosed on the basis of neuroradiological studies. Surgery was applied in all cases. Implantation of internal stabilization followed vertebral haemangioma resection. Results Localization of vertebral haemangiomas included 1 case in the cervical, 5 cases in the thoracic and 1 case in the lumbar segment of the vertebral column. Symptoms of medulla compression were observed in 7 patients. Neurological symptoms were caused usually by hypertrophy or ballooning of the posterior cortex of the vertebral body into the vertebral canal. The anterior surgical approach was carried out in 2 cases, posterolateral in 3 cases and posterior in 2 cases. Spinal stability was secured by various implant systems and autogenic bone grafts. Bone defects in the vertebral body were filled with acrylic cement in 4 patients. In histological examinations, cavernous types were found in all patients. Neurological condition improved after the treatment in 5 patients. Conclusions No standard therapy exists for symptomatic thoracic vertebral haemangiomas. However, immediate surgical intervention is necessary in cases with acute compressive myelopathy before the symptoms become irreversible.Wstęp i cel pracy Naczyniak kręgosłupa jest najczęstszym pierwotnym guzem kostnym kręgosłupa. Tylko 0,9—1,2% naczyniaków powoduje neurologiczne objawy ubytkowe. W pracy przedstawiono wskazania, techniki operacyjne i sposoby stabilizacji u chorych leczonych z powodu objawowych naczyniaków kręgosłupa. Materiał i metody Analizą kliniczną objęto 7 chorych leczonych w latach 1995—2007, w tym 4 kobiety i 3 mężczyzn w wieku od 24 do 63 lat (średnia wieku wynosiła 44 lata). Diagnostyka opierała się na badaniach neuroradiologicznych. Wszyscy chorzy byli leczeni chirurgicznie. Po usunięciu naczyniaka przeprowadzano stabilizację wewnętrzną kręgosłupa metalowymi implantami i autogennym przeszczepem kostnym. Ubytek w trzonie kręgu w 4 przypadkach został wypełniony cementem akrylowym. Wyniki Naczyniaki kręgosłupa występowały najczęściej w odcinku piersiowym — 5 przypadków, w odcinkach szyjnym i lędźwiowym — po 1 przypadku. Objawy kliniczne ucisku rdzenia kręgowego stwierdzono u wszystkich chorych. Naczyniaki powodowały ucisk rdzenia kręgowego przez przerost i balonowate uwypuklenie zwykle tylnej ściany trzonu kręgowego. Przednie dojście operacyjne wykonano w 2 przypadkach, tylno-boczne w 3 przypadkach, a tylne w 2 przypadkach. W badaniu histologicznym u wszystkich chorych stwierdzono naczyniaki jamiste. Poprawę stanu neurologicznego obserwowano u 5 pacjentów. Wnioski Nie ma ustalonych standardów leczenia u chorych z objawowymi naczyniakami kręgosłupa. Interwencja chirurgiczna polegająca na uwolnieniu rdzenia kręgowego z ucisku jest konieczna w przypadkach narastających neurologicznych objawów ubytkowych

    Electron-molecular vibration coupling in (DMtTTF)Br and (o-DMTTF)2[W6O19] salts studied by vibrational spectroscopy

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    International audienceA novel 1:1 salt encompassing radical cations of DMtTTF (DMtTTF = dimethyltrimethylene-tetrathiafulvalene) and the Br−anion has been synthesized. Close inspection of the salt's solid state structure revealed the presence of quasi-isolated dimers containing DMtTTF radical cations, a specific arrangement whereby the microscopic parameters of DMtTTFradical dot+ might be studied. Analysis of the corresponding single crystal IR and Raman spectra of (DMtTTF)Br allowed us to study the material's electronic and vibrational structure and to evaluate the electron-molecular coupling constants via the isolated dimer model. Additionally, using previously published IR data, analogous calculations were performed on the salt (o-DMTTF)2[W6O19] (o-DMTTF = o-3,4-dimethyltetrathiafulvalene), which also contains well isolated dimers of o-DMTTF radical cations. These calculations revealed that the coupling constants for the unsymmetrical donors studied herein are comparable to those for symmetric TTF derivatives

    Occupational risks for SARS-CoV-2 infection : the Polish experience

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    The disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), termed COVID-19, is asymptomatic or mild in most cases. These patients do not need treatment in hospital and can be isolated at home. To date, most studies have been conducted among inpatients with severe COVID-19. In this study, the authors surveyed patients with mild COVID-19 who remained in home isolation, and analyzed the sources and occupational risk factors for SARS-CoV-2 infections. Material and Methods: This cross-sectional study was carried out on April 17-18, 2020, among patients infected with SARS-CoV-2 who remained in home isolation in Poland. Data were acquired through a structured interview that included questions about the isolation course, symptoms, comorbidities, infection source, household characteristics, occupation, and workplace. Data were presented with descriptive statistics. Results: Of the 4878 patients in home isolation, the authors were able to contact 3313. Of them, 1191 patients declined their invitation, and 2122 agreed to take part. The median age of the patients included in the study was 50 years; 59% were female. Most patients (92%) had not been abroad before the infection. More than half (55%) knew how they became infected; of them, 75% became infected at work. Of all patients, 70% were occupationally active. Nearly half of the occupationally active patients (48%) worked in healthcare, 3% worked in public administration or defense, 3% worked in transportation, and 2% worked in education. Sixty-five percent of the occupationally active patients worked in companies with >100 employees. Conclusions: Most of the patients with COVID-19 in home isolation in Poland were occupationally active, wherein the majority of people who were aware of the source of SARS-CoV-2 infection worked in healthcare. As most of the infected patients worked in companies with >100 employees, which is not a Polish employment pattern, the authors expect that smaller companies may have a lower risk of SARS-CoV-2 infections

    Cardiovascular risk management in type 2 diabetes of more than 10-year duration: Results of Polish ARETAEUS2-Grupa Study

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    Background: ARETAEUS 1 study showed that a great majority of patients with type 2 dia­betes mellitus (T2DM) of short duration did not meet all of the treatment goals. Since then the treatment goals in T2DM have been changed. The aim of the ARETAEUS 2-Grupa Study was to assess cardiovascular (CV) risk management and meeting treatment goals in the population of T2DM of more than 10-year duration. Methods: ARETAEUS2-Grupa was a cross-sectional questionnaire-based study conducted in Poland in 2012. Randomly selected physicians recruited 1,740 patients with T2DM diag­nosed more than 10 years before the study. Results: Lipid treatment goals were met respectively: for total cholesterol in 34.5% of all patients, triglycerides in 53.8%, low density lipoprotein cholesterol (LDL-C) in 26.5% and high density lipoprotein cholesterol (HDL-C) in 38.2%. Most of patients with and without coronary artery disease were receiving aspirin (90.3% and 60%, respectively) and statins (84.4% and 67.7%, respectively). The current blood pressure (BP) goal (140/90 mm Hg) was met in 43.5% of pa­tients and the previous goal (&lt; 130/80 mm Hg) in 12.4%. The patients were mainly treated with ≥ 3 antihypertensive drugs. All treatment goals (for HbA1c, BP and LDL-C) were reached only by 8.2% of patients, any two goals by 26.3% of patients, one goal by 39.8% of patients, none by 25.6% of patients. Conclusions: The new less restrictive treatment goals are reached more frequently but still much is to be done in the field of clinical practice guidelines implementation and CV prevention in T2DM population
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