Uticaj endotelina i L-NAME na koncentraciju mokraćne kiseline i uree u plazmi kod Wistar pacova

Effects of endothelins, which include vasoconstriction and vasodilatation are possible by different molecular mechanisms. Endothelins induce increased synthesis of nitric oxide which in turn inhibits the synthesis of endothelin. Changes in biochemical parameters connected with the increased and decreased synthesis of nitric oxide are not thoroughly examined yet. In a series of experiments we compared the effects of endothelin (ET-1) on the inhibition of nitric oxide synthase (NOS), as well as the effects of L-nitro arginin metal estar (L-NAME) on plasma urea and uric acid concentration. Experiments were performed on anesthetized female adult Wistar rats. The experimental groups received an i. v. bolus of ET-1, L-NAME or saline. All parameters, heamodynamic and biochemical, were measured before the animals were sacrificed. L-NAME increased the mean arterial pressure, decreased renal blood flow and increased vascular resistance in carotid and renal arteries and increased in plasma uric acid and urea concentrations. ET- 1 significantly decreased uric acid concentration in the plasma but did not effect plasma urea concentration compared to the control group. These differences show complex relations of nitric oxide with cellular signalization compared to the basic NO-cGMP pathway.Efekti endotelina koji uključuju vazokonstrikciju I vazodilataciju ostvaruju se različitim molekularnim mehanizmima. Endotelin indukuje povećanu sintezu azotnog oksida za koji se smatra da povratno inhibira sintezu endotelina. Promene biohemijskih parametara vezanih za povećanu i smanjenu sintezu NO nisu dovoljno proučene. U ovom radu su upoređeni efekti endotelina (ET-1) i inhibitora NOS-a, L-NAME na koncentraciju mokraćne kiseline i uree u plazmi. Eksperimenti su izvedeni na anesteziranim odraslim NW pacovima, ženskog pola. Eksperimentalne životinje su u i.v. bolusu primale ET-1, L-NAME ili fiziološki rastvor. Svi hemodinamski i biohemijski parametri su mereni pre žrtvovanja. L-NAME dovodi do povećanja srednjeg arterijskog pritiska smanjenja renalnog protoka i povećanja vaskularnog otpora u karotidnoj i renalnoj arteriji i povećanja koncentracije mokraćne kiseline i uree u plazmi. ET-1 značajno smanjuje koncentraciju mokraćne kiseline u plazmi ali ne utiče na koncentraciju uree u odnosu na kontrolu. Ove razlike pokazuju kompleksnije relacije NO-a sa ćelijskom signalizacijom u odnosu na osnovni NO-cGMP put

Intelligent thermopile-based vacuum sensor

We report here the development of a simple and low-cost intelligent vacuum sensor based on multipurpose thermopile MEMS chips. Our devices have a p(+)Si heater and two thermopiles with 30 p(+)Si/Al thermocouples each. Thermal and electrical isolation is provided by a sandwich membrane (residual n-Si and sputtered oxide). The sensor utilizes for its intelligent mode of operation a modified version of an existing processing module we developed for our piezoresistive sensors

Electronic structure of the substitutional vacancy in graphene: density-functional and Greens function studies (vol 14, 083004, 2012)

Link to the corrected article: [https://vinar.vin.bg.ac.rs/handle/123456789/4991

Prognostic Value of RV Function Before and After Lung Transplantation

AbstractObjectivesWe investigated the effects of lung transplantation on right ventricular (RV) function as well as the prognostic value of pre- and post-transplantation RV function.BackgroundAlthough lung transplantation success has improved over recent decades, outcomes remain a challenge. Identifying predictors of mortality in lung transplant recipients may lead to improved long-term outcomes after lung transplantation.MethodsEighty-nine (age 60 ± 6 years, 58 men) consecutive patients who underwent single or double lung transplantation and had pre- and post-transplantation echocardiograms between July 2001 and August 2012 were evaluated. Echocardiographic measurements were performed before and after lung transplantation. Left ventricular (LV) and RV longitudinal strains were analyzed using velocity vector imaging. Cox proportional prognostic hazard models predicting all-cause death were built.ResultsThere were 46 all-cause (52%) and 17 cardiac (19%) deaths during 43 ± 33 months of follow-up. After lung transplantation, echocardiography showed improved systolic pulmonary artery pressure (SPAP) (50 ± 19 mm Hg to 40 ± 13 mm Hg) and RV strain (−17 ± 5% to −18 ± 4%). No pre-transplantation RV parameter predicted all-cause mortality. After adjustment for age, sex, surgery type, and etiology of lung disease in a Cox proportional hazards model, both post-transplantation RV strain (hazard ratio: 1.13, 95% confidence interval: 1.04 to 1.23, p = 0.005), and post-transplantation SPAP (hazard ratio: 1.03, 95% confidence interval: 1.01 to 1.05, p = 0.011) were independent predictors of all-cause mortality. When post-transplantation RV strain and post-transplantation SPAP were added the clinical predictive model based on age, sex, surgery type, and etiology, the C-statistic improves from 0.60 to 0.80 (p = 0.002).ConclusionsAlterations of RV function and pulmonary artery pressure normalize, and post-transplantation RV function may provide prognostic data in patients after lung transplantation. Our study is based on a highly and retrospectively selected group. We believe that larger prospective studies are warranted to confirm this result

Application of the modeling method to the calculation of the probability of hitting a stationary target during the fire action of a tank squad in defense

Introduction/purpose: The theory of direct firing of armored units deals with the calculation of the probability of hitting the target depending on the number of projectiles fired, in certain combat circumstances as well as under certain meteorological conditions. Successful performance of the combat task of armored units in defensive actions against stationary targets depends to the greatest extent on the effectiveness of fire of tank weapons. Under the tactical assumptions that define real combat conditions, i.e., that the attacking formation opens fire from small arms and anti-tank weapons, that the defense is organized in a timely manner on maneuvering ground and in optimal meteorological conditions, and that the tank squad opens fire while stationary, the scientific goal of the research is to determine the probability of hitting and destroying the target as closely as possible depending on the method of determining the distance to the target and the number of projectiles fired. Methods: Mainly applying the method of situation modeling in scientific research, the authors try to determine, as precisely as possible, the percentage of the probability of hitting (destroying) a stationary target, with the first, second, or third projectile. Results: The main scientific contribution of the research would be the determination of various quantitative indicators as significant parameters necessary for a successful design of defense operations of ground army units. Conclusion: By creating an appropriate model for a specific situation in order to solve a problem (combat task), it is possible to precisely determine the probability of hitting and the probability of destroying the target in relation to the number of projectiles fired, as well as the expected consumption of ammunition

The effect of antioxidant status on overall survival in renal cell carcinoma

Introduction The oxidative stress contributes to all three phases of carcinogenesis and represents a concomitant condition in renal cell carcinoma (RCC). RCC is the most common type of neoplasm of the kidney, and despite numerous studies the set of predictive and prognostic markers of survival are still unknown. The aim of our study was to examine the relation between antioxidant (AO) status and overall survival (OS) in RCC patients. Material and methods Our study included 95 patients with RCC, who underwent radical nephrectomy. We analysed the prognostic role of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, glutathione, and malondialde-hyde) and other clinicopathological factors (size, grade, stage, and histological subtype) on the OS of RCC patients. Results The 5-year OS was 54.6%. The survival analysis related to AO parameters showed no significant difference in survival of RCC patients. The concentration of malondialdehyde, an indicator of lipid peroxidation, also had no significant effect on the survival rate of RCC pa-tients. Univariate and multivariate analysis confirmed the significance of clinicopathological parameters (size, p < 0.001; Fuhrman grade, p = 0.001, and stage, p < 0.001) for patients’ survival. Conclusions In our cohort of patients, different antioxidant parameters were not found to be predictors for OS of patients with RCC, who underwent radical nephrectomy

Effect of Fe2+ (Fe3+) Doping on Structural Properties of CeO2 Nanocrystals

We have measured the Raman scattering and magnetization of pure and Fe2+(Fe3+) doped CeO2 nanopowders at room temperature. The Raman scattering spectra revealed the existence of CeO2 fluorite cubic structure for all investigated samples. The Raman active mode at about 600 cm(-1), seen in all samples, can be ascribed to the CeO2 intrinsic oxygen vacancies. Additional Raman modes at 720 cm(-1), 1320 cm(-1) and 1600 cm(-1), which appear in the spectra of doped samples, can be assigned to maghemite (gamma-Fe2O3) cation deficient structure, to 2 omega(LO) IR-allowed overtone and two magnon structure, respectively. This implies that our powders are composed of mixed valence states and have defective structure. Presence of oxygen defect states and magnetic ions can be responsible for the observed ferromagnetism at room temperature in both pure and Fe doped samples.Symposium on Raman Scattering in Materials Science, Sep 15-19, 2008, Warsaw, Polan

Hydrothermal Synthesis of CeO2 and Ce0.9Fe0.1O2 Nanocrystals

Pure and 10 mol% Fe3+ doped CeO2 nanocrystals were synthesized by hydrothermal method using two different basic solutions (NH4OH and NaOH). All the samples were calcinated at 140 degrees C and 200 degrees C. The characterization of crystalline structure, vibrational and optical properties was performed using X-ray diffraction, Raman spectroscopy and spectroscopic ellipsometry. The obtained results showed that the Fe-doped samples are solid solutions with different size of nanocrystals, very dependent on the synthesis temperature and type of basic solution. The Raman measurements demonstrated electron molecular vibrational coupling and increase of oxygen vacancy concentration whereas doping provokes a small decrease of optical absorption edge in comparison with pure ceria.International School and Conference on Photonics (PHOTONICA09), Aug 24-28, 2009, Belgrade, Serbi