O Brocardovim točkama harmoničnog četverokuta u izotropnoj ravnini

In this paper we present some new results on Brocard points of a harmonic quadrangle in isotropic plane. We construct new harmonic quadrangles associated to the given one and study their properties dealing with Brocard points.U radu se prikazuju neki novi rezultati o Brocardovim točkama harmoničnog četverokuta u izotropnoj ravnini. Konstruiraju se novi harmonični četverokuti pridruženi danom četverokutu, te se proučavaju njihova svojstva vezana uz Brocardove točke

Parabolas in the isotropic plane

In this paper we study the properties of a parabola in an isotropic plane and compare the results obtained with their Euclidean analogues

A Complete Quadrilateral in Rectangular Coordinates

U radu proučavamo potpuni četverostran u euklidskoj ravnini. Poput trokuta i potpuni četverostran ima mnogo zanimljivih svojstava te pridruženih točaka, pravaca i konika. Ovdje je proučavanje provedeno korištenjem pravokutnih koordinata, simetrično po sve četiri stranice četverostrana s četiri parametra a, b, c, d. Proučavamo svojstva točaka, pravaca i kružnica pridruženih četverostranu. Gotovo sve tvrdnje prikazane u ovom radu su dobro poznate, ali su se ipak ponegdje usput pojavili i neki novi rezultati.A complete quadrilateral in the Euclidean plane is studied. The geometry of such quadrilateral is almost as rich as the geometry of a triangle, so there are lot of associated points, lines and conics. Hereby, the study was performed in the rectangular coordinates, symmetrically on all four sides of the quadrilateral with four parameters a, b, c, d. In this paper we will study the properties of some points, lines and circles associated to the quadrilateral. All these properties are well known, but here they are all proved by the same method. During this process, still some new results have appeared

Covertex trokuti upisani paraboli u izotropnoj ravnini

In the paper the concept of a covertex inscribed triangle of a parabola in an isotropic plane is introduced. It is a triangle inscribed to the parabola that has the centroid on the axis of parabola, i.e. whose circumcircle passes through the vertex of the parabola. We determine the coordinates of the triangle centers, and the equations of the lines, circles and conics related to the triangle.U radu se uvodi pojam covertex trokuta upisanog paraboli u izotropnoj ravnini. To je trokut upisan paraboli čije težište leži na osi parabole, tj. čija opisana kružnica prolazi tjemenom parabole. Određuju se koordinate točaka te jednadžbe pravaca, kružnica i konika povezanih s tim trokutom

The distance-based approach to the quantification of the world convergences and imbalances - comparisons across countries and factors

The paper presents a general empirical method of distance-based multifaceted systematic identifying of the positions of countries in relation to inequalities and imbalances. In order to understand the world economic relations in their entirety, we decided to analyze twelve most populous countries and eleven macroeconomic, environmental and demographic indicators relevant to them. Our analysis covering the period 1992-2008 attempts to identify core parts of the global economic system and countries that pose a potential risk of instability

Cooperation between STAT3 and c-Jun Suppresses Fas Transcription

Decreased Fas expression during tumor progression often results in a loss of Fas-ligand (FasL)-mediated apoptosis. Human and mouse melanoma exhibit an inverse correlation between the degree of Fas cell surface expression, tumorigenicity, and metastatic capacity. The expression of dominant negative Stat3 or c-Jun in melanoma cells efficiently increased Fas expression and sensitized cells to FasL-induced apoptosis. Stat3+/− as well as c-Jun−/− cells exhibited increased Fas cell surface expression and higher sensitivity to FasL-mediated apoptosis. Suppression of Fas expression by Stat3 and c-Jun is uncoupled from Stat3-mediated transcriptional activation. Our findings indicate that Stat3 oncogenic activities could also be mediated through its cooperation with c-Jun, resulting in downregulation of Fas surface expression, which is implicated in the tumor's ability to resist therapy and metastasize

Prevalence of donor-transmitted atherosclerosis—Clinical utility of intracoronary ultrasound early after heart transplantation. A single-center study

AbstractIntroductionCoronary allograft vasculopathy (CAV) is one of the main factors limiting long-term survival following orthotopic heart transplantation (HTx). Whether or not and, if so, how donor-transmitted atherosclerosis (DCA) affects the post-transplant course of the allograft recipient is still unclear. Conventional coronary angiography is a moderately accurate technique for DCA detection as it will reveal only the more gross morphological lesions. By contrast, intravascular ultrasound (IVUS) has been shown to be a much more sensitive technique for CAV and DCA detection. In our study we sought to determine the prevalence of DCA in our HTx patient population and identify main risk factors of DCA based on donor characteristics.Patients and methodsWe performed a retrospective analysis of data of 119 patients (92 men, 27 women) undergoing transplantation in our center from August 2006 through September 2012, who had survived their first post-transplant month and had coronary angiography and IVUS.ResultsDCA was present in 39 patients, and not documented in 80 patients. The main risk factors for DCA included donor age, cigarette smoking, and hypertension; the other parameters were not shown to be statistically significant. In-hospital mortality was low in both groups (DCA positive and DCA negative), with one patient dying in either group. One-year mortality rates post-HTx were likewise almost identical in both groups (15.4% and 15% in DCA positive and negative, respectively).ConclusionThe prevalence of DCA in our patients was 32.8%, with major risk factors for DCA including donor age, cigarette smoking, and hypertension. As age seems to be the strongest predictor, coronary angiography should be a routine examination in individuals aged over 40 years; the examination should be considered in younger individuals with a cluster of several of risk factors. The 1-year survival in this selected patient population was identical in both groups, the implication being that the diagnosis of DCA had no effect on 1-year survival post-HTx

Influence of anodization voltage on photocatalztic activity of TiO2 nanotubes

TiO2 under UV light generates charge carriers (electrons and holes) that take part in the process of decomposition of pollutants, which is a well-known fact for the past few decades. For this reason, TiO2 is used for photocatalytic purification water and air. Photoactivity of TiO2 depends on the amount of generated charge carriers, and one part of those carriers are lost through the process of recombination. In order to improve photoactivity, it is necessary to speed up transport of electrons and holes. For better and faster charge carrier transport a unidirectional path is desired, which can be obtained by synthesizing 1D morphology. Anodization of titanium foil is a good way to obtain perpendicular nanotubular morphology onto a substrate. Nanotubular morphology can be optimized via operative conditions of anodization: applied voltage, anodization time and type of electrolyte. In this work, TiO2 nanotube arrays were synthesized by anodization of titanium foil at different voltages: 10 V, 15 V, 20 V and 25 V. Based on FESEM (Field Emission Scanning Electron Microscopy) micrographs, the microstructure of nanotubes was analysed and data concerning wall thickness, outer diameter of nanotubes and active surface were considered. Also, the influence of nanotube morphology on optical properties was determined. Results of our research show that the increasement in anodization voltage influenced on the appearance of redshift in the absorption spectrum. The sample synthesized at 20 V showed the highest photocatalytic activity due to the optimal nanotube length and nanotube diameter