25 research outputs found

    Far-infrared spectroscopy of PbTe doped with iron

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    Far infrared reflection spectra, at room and liquid nitrogen temperature, of PbTe single crystals doped with iron are presented. Plasma minima were observed at about 160 cmā€“1 and 180 cmā€“1 for room and liquid nitrogen temperature, respectively. Using the reflectivity diagrams and their minima the values of the hole concentrations and their mobility at both temperatures were calculated and compared with galvanomagnetic measurements. All these results indicated that when PbTe is doped with a small concentration of Fe, the hole concentration is reduced by one order of magnitude and the free carrier mobility is larger when compared to pure PbTe

    The Design and Simulation of an Astronomical Clock

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    This paper describes and explains the synthesis of an astronomical clock mechanism which displays the mean position of the Sun, the Moon, the lunar node and zodiac circle as well as the Moon phases and their motion during the year as seen from the Earth. The clock face represents the stereographic projection of the celestial equator, celestial tropics, zodiac circle (ecliptic) and horizon for the latitude of Belgrade from the north celestial pole to the equator plane. The observed motions of celestial objects are realized by a set of clock gear trains with properly calculated gear ratios. The method of continued fraction is applied in the computation of proper and practically applicable gear ratios of the clock gear trains. The fully operational 3D model of the astronomical clock is created and the motion study of its operation is accomplished by using the SolidWorks 2016 application. The simulation results are compared with the ephemeris data and the detected differences are used to evaluate the long-term accuracy of the astronomical clock operation. The presented methods of the clock mechanism synthesis can be useful for the design, maintenance and conservation of large-scale city astronomical clocks since these clocks represent a precious historical and cultural heritage of European civilization

    The Design and Simulation of an Astronomical Clock

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    This paper describes and explains the synthesis of an astronomical clock mechanism which displays the mean position of the Sun, the Moon, the lunar node and zodiac circle as well as the Moon phases and their motion during the year as seen from the Earth. The clock face represents the stereographic projection of the celestial equator, celestial tropics, zodiac circle (ecliptic) and horizon for the latitude of Belgrade from the north celestial pole to the equator plane. The observed motions of celestial objects are realized by a set of clock gear trains with properly calculated gear ratios. The method of continued fraction is applied in the computation of proper and practically applicable gear ratios of the clock gear trains. The fully operational 3D model of the astronomical clock is created and the motion study of its operation is accomplished by using the SolidWorks 2016 application. The simulation results are compared with the ephemeris data and the detected differences are used to evaluate the long-term accuracy of the astronomical clock operation. The presented methods of the clock mechanism synthesis can be useful for the design, maintenance and conservation of large-scale city astronomical clocks since these clocks represent a precious historical and cultural heritage of European civilization

    Semantic Search Engine as tool for clinical decision support in Register for Acute Coronary Syndrome

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    This paper presents the implementation and use of Semantic Search Engine (SSE) as part of knowledge management system functionalities in Register for Acute Coronary Syndrome (REACS). REACS SSE is part of a clinical decision support system and is used as an aid in decision making in clinical processes related to the care and treatment of patients with Acute Coronary Syndrome (ACS)

    Characteristics, outcome and predictors of one year mortality rate in patients with acute heart failure

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    Background/Aim. Acute heart failure (AHF) is one of the most common diseases in emergency medicine, associated with poor prognosis and high in-hospital and longterm mortality. The aim of this study was to investigate characteristics, outcomes and one year mortality of patients with AHF in the local population. Methods. This prospective study consisted of 64 consecutive unselected patients treated in the Coronary Care Unit of the Emergency Centre (Clinical Center of Serbia, Belgrade) and were followed for one year after the discharge. Results. Mean age of the patients was 63.6 Ā± 12.6 years and 59.4% were males. Acute congestion (43.8%) and pulmonary edema (39.1%) were the most common presentations of AHF. Mean left ventricular ejection fraction (LVEF) was 39.7% Ā± 9.25%, while 44.4% of the patients had LVEF ā‰„ 50%. At discharge, 55.9% of the patients received therapy with Ī²-blockers, 94.9% diuretics, out of which 47.7% spironolactone, 94.9% patients were given ACE-inhibitors or angiotensin receptor blokcers (ARB). The 12-month all-cause mortality was 26.5%. Independent predictors of one year mortality were previous hospitalization due to heart disease, reduced LVEF, reduced fraction of shortening (FS) and a higher tricuspid velocity. Conclusion. One year mortality of our patients with AHF was high, similar to the known European studies. Independent predictors of one year mortality were previous hospitalization due to heart disease, reduced LVEF and LVFS and a higher tricuspid velocity

    Risks for First Nonfatal Myocardial Infarction in Belgrade

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    The aim of this study was to investigate which one among possible risk factors are independently related to first nonfatal myocardial infarction (MI) in Belgrade population. Case-control study was conducted in Belgrade during the period 2005ā€“2006. Case group comprised 100 subjects 35ā€“80 years old who were hospitalized because of first nonfatal MI at the coronary care unit in Urgent Center, Belgrade. Control group consisted of 100 persons chosen among patients treated during the same period at the Institute of Rheumatology, Institute for Gastroenterology, and Clinic for Orthopedics, Belgrade, Serbia. Cases and controls were individually matched by sex, age (Ā±2 years) and place of residence (urban/ rural communities of Belgrade). According to the multivariate analysis risk factors for MI occurrence were Ā»goodĀ« socioeconomic conditions (OR=2.76), total alcohol consumption (OR=2.62) and consumption of brandy (OR=6.73), stressful life events taken together (OR=3.13) and stress because of close relative Ns death (OR=3.35), great financial problems (OR=31.64) and small financial problems (OR=8.47), hypertension (OR=2.39), MI among all relatives (OR=3.66), MI in father (OR=6.24), and low level of high density lipoprotein cholesterol (OR=152.41). Amateur sport activity in the past was negatively associated with MI development. The results obtained are mainly in accordance with other studies results and can be of help in development of strategy for coronary heart disease prevention in Serbia

    PostmarketinŔka studija efikasnosti i bezbednosti primene losartana u lečenju bolesnika s umerenom i blagom arterijskom hipertenzijom - studija Lotnar

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    Introduction. Losartan, the angiotensin type 1 receptor blocker (ARB) exercises its main antihypertensive effect by vasodilatation of peripheral arteries. Objective. The aim of this study was to evaluate the antihypertensive effect and safety of losartan in patients with mild and moderate arterial hypertension (AH). Methods. This was an open post-marketing study with losartan as monotherapy in previously treated or untreated patients with AH. Primary efficacy parameter was the percentage of patients that achieved target blood pressure after 8-week treatment with a single daily dose of losartan of 50-100 mg. Safety parameters were assessed according to the percentage of adverse events and metabolic effects of therapy. Results. The study included 550 patients with AH (59% female and 41% male), mean age 56.8Ā±11.4 years, BMI=27Ā±4 kg/m2. Losartan was applied in 31% of untreated and 69% of previously treatment-resistant patients After 8 weeks target blood pressure was achieved in 67.8% (SBP) and in 81.1% (DBP) of patients, respectively. The mean decrease was 21.8% for SBP and 21.1% for DBP (p lt 0.001). Out of all, 65% of patients achieved both target SBP and DBP values. Hydrochlorothiazide was added to the therapy in 11.6% of patients. There were no significant differences in drug efficacy between the entire group and subgroups of patients with diabetes mellitus and impaired renal function (p=ns). Adverse events were rare and metabolic effect was favorable. Conclusion. Monotherapy with losartan in a dosage of 50-100 mg applied during 8 weeks resulted in achieving target values of blood pressure in 65% of patient with mild and moderate hypertension, also including the patients with diabetes mellitus and impaired renal function. Losartan is a safe and metabolically neutral medication.Uvod. Losartan, blokator angiotenzinskog receptora tip 1 (ARB), antihipertenzivni efekat ostvaruje vazodilatacijom perifernih arterija. Cilj rada. Cilj studije je bio da se procene efikasnost i bezbednost primene losartana kod bolesnika s arterijskom hipertenzijom blagog i umerenog stepena. Metode rada. U otvorenoj postmarketinÅ”koj studiji losartan je primenjen kao monoterapija kod bolesnika s prethodno lečenom ili nelečenom umerenom i blagom hipertenzijom tokom osam nedelja u dozi od 50 mg i 100 mg jednom dnevno, uz posmatranje promene procenta bolesnika kod kojih su dostignute ciljne vrednosti sistolnog (SAP) i dijastolnog arterijskog krvnog pritiska (DAP). Bezbednost primene leka procenjena je prema procentu neželjenih dejstava i metaboličkim efektima terapije. Rezultati. U studiju je uključeno 550 bolesnika (59% žena i 41% muÅ”karaca) prosečne starosti od 56,8Ā±11,4 godine i prosečnog indeksa telesne mase (BMI) od 27Ā±4 kg/m2. Losartan je primenjen kod 31% nelečenih i 69% prethodno lečenih bolesnika ali s neregulisanom hipertenzijom. Posle osam nedelja ciljne vrednosti SAP su postignute kod 67,8% bolesnika, a DAP kod 81,1% (i SAP i DAP kod 65% bolesnika), s prosečnim smanjenjem SAP od 21,8% i DAP od 21,1% (p lt 0,001). Hidrohlorotijazid je dodat terapiji kod samo 11,6% bolesnika. Terapijski efekti se nisu statistički značajno razlikovali između svih bolesnika i podgrupa ispitanika sa dijabetes melitusom (DM) i smanjenom funkcijom bubrega. Neželjena dejstva leka su bila retka, a metabolički efekat bio je povoljan. Zaključak. Monoterapija losartanom dovodi do postizanja ciljnih vrednosti krvnog pritiska kod 65% bolesnika sa blagom i umerenom hipertenzijom tokom osam nedelja primene, uključujući i bolesnike sa DM i sa smanjenom funkcijom bubrega. Losartan je siguran i metabolički neutralan lek

    Obstacles in the Diagnostics and Therapy of Heparin-Induced Thrombocytopenia

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    An immune-mediated, severe, acquired prothrombotic disorder, heparin-induced thrombocytopenia type II (HIT II) occurs in 0.5-5% of patients exposed to unfractionated heparin longer than 5-7 days. Arterial and venous thromboses are induced by HIT II in about 35-50% of patients. Typical death rate for HIT is about 29%, while 21% of HIT patients result in amputation of a limb. The trend towards the occurrence of HIT due to the administration of low molecular weight heparins (LMWH) taking ever conspicuous place in the standard venous thromboembolism (VTE) prophylaxis has been more frequently observed recently. It is considered that LMWH may cause HIT II in about 0.25-1%. The need for further modification of HIPA assays with LMWH has been imposed in the HIT laboratory diagnostics, heretofore overburdened with complexity. There are several constantly opposing problems arising in HIT laboratory diagnostics, one of which is that in a certain number of patients immunologic assays detect nonpathogenic antibodies (mainly IgM or IgA heparin-PF4 antibodies) while, on the other hand, the occurrence of HIT pathogenetically mediated by minor antigens (neutrophil-activating peptide 2 or interleukin 8) may be neglected in certain cases. The following factors play an important role in the interpretation of each laboratory HIT assays performed: 1. correlation with HIT clinical probability test, the best known of which is 4T'score, 2. the interpretation of the laboratory findings dependent on the time of the thrombocytopenia onset, as well as 3. the sensitivity and specificity of each test respectively. The HIT diagnostics in the presence of other comorbid states which may also induce thrombocytopenia, more precisely known as pseudo HIT (cancer, sepsis, disseminated intravascular coagulation, pulmonary embolism, antiphospholipid syndrome, etc), represents a specific clinical problem

    Incidence of hyperhomocysteinemia and Mthfr C677T polymorphism among young patients with acute myocardial infarction

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    Hyperhomocysteinemia is considered an independent risk factor for premature cardiovascular disease. Mutation MTHFR C677T reduces the activity of methylenetetra-hydrofolatereductase and may cause hyperhomocysteinemia. Incidence of hyperhomocysteinemia (homocysteine above 12 mu mol/L), homocysteine level, and distribution of MTHFR C677T genotypes (C/C, C/T and T/T) are T/T) are compared between young patients with acute myocardial infarction and healthy persons, matched by age. Study involved 86 patients younger than 45 years (77 men and 9 women) and 35 controls. Homocysteine was measured by an HPLC method and the MTHFR C677T genotype determined using PCR amplification and digestion with Hinf I. Statistical analyses included chisquare and Mann-Whitney U tests. Hyperhomocysteinemia was present in 32.6% patients and 14.3% controls, revealing a significant difference (P = 0.038). Median homocysteine levels in patients (10.4 mu mol/L) and controls (9.6 mu mol/L) were significantly different (P=0.035). Among patients, 50.0% had C/C, 41.9% C/T and 8.1% T/T genotype, and the genotype had no influence on hyperhomocysteinemia incidence and homocysteine level. Genotype distribution in patients was not significantly different from the observed in controls. The conclusion is that young patients with acute myocardial infarction have higher incidence of hyperhomocysteinemia and higher homocysteine levels than healthy young adults, while there is no significant difference in the distribution of MTHFR C677T genotypes

    Specijalni alat za interni transport strukturnih elemenata Ŕinskih vozila - SPECIAL TOOL FOR INTERNAL TRANSPORT OF STRUCTURAL ELEMENTS OF RAIL VEHICLES

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    Pronalazak u Å”irem smislu pripada uređajima za rukovanje i transport, a u užem smislu pronalazak se odnosi na uređaje za prihvatanje tereta koji se koriste na uređajima za rukovanje, podizanje i interni transport aluminijumskih elemenata, podsklopova i sklopova nosećih struktura različitih vrsta Å”inskih vozila, koji se koriste u industriji Å”inskih vozila
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