National culture and the entrepreneurial intentions of students in Serbia

The paper presents the results of research into the influence of national culture on the enterprise potential, individual entrepreneurial orientation and entrepreneurial intentions of students in Serbia. The moderating and mediating effects of the possession of finance for opening one’s own company item on the observed relations were examined. National culture has a positive influence on entrepreneurship in cases where young people want to overcome the unfavourable circumstances in society and engage in entrepreneurship in order to become independent. In the case of a poor financial situation a stable environment is what can encourage the launch of one's own business.

Pd(II) complexes with N-heteroaromatic hydrazone ligands: Anticancer activity, in silico and experimental target identification

Anticancer activity of Pd complexes 1-5 with bidentate N-heteroaromatic hydrazone ligands was investigated on human acute monocytic leukemia (THP-1; cells in a suspension) and human mammary adenocarcinoma (MCF-7; two-dimensional layer and three-dimensional spheroid tumor model) cell lines. For the Pd(II) complexes with condensation products of ethyl hydrazainoacetate and quinoline-8-carboxaldehyde (complex 1) and 2-formylpyridine (complex 3), for which apoptosis was determined as a mechanism of anticancer activity, further investigation revealed that they arrest the cell cycle in G0/G1 phase, induce generation of reactive oxygen species and inhibit Topoisomerase I in vitro. In silico studies corroborate experimental findings that these complexes show topoisomerase inhibition activity in the micromolar range and indicate binding to a DNA's minor groove as another potential target. Based on the results obtained by circular dichroism and fluorescence spectroscopy measurements, the most active complexes are suitable to be delivered to a blood stream via human serum albumin.

Characterisation and the effects of bilirubin binding to human fibrinogen

Fibrinogen, a protein involved in blood coagulation, is very susceptible to oxidation. Oxidation alters its function and usually makes it more thrombogenic. Bilirubin, an end-product of the haem degradation in vertebrates, is known for its antioxidant properties. The present paper describes interaction between fibrinogen and bilirubin, and the influence of bilirubin on the formation of fibrin and protection against oxidation. The binding constant of 4.5 × 10⁴ M^-1 was determined for the fibrinogen/bilirubin complex at 37 °C. There is no change in secondary and tertiary structure of fibrinogen or its thermal stability upon bilirubin binding. The binding site of fibrinogen is not stereospecific for bilirubin and is able to accommodate both bilirubin conformers. A change in absorption maximum of bilirubin occurs upon its interaction with fibrinogen, suggesting an alteration in the conformation of bilirubin to the more cyclic one. Bilirubin exerts antioxidant effect on fibrinogen, preventing its carbonylation and aggregation. The presence of bilirubin induces the formation of fibrin with thicker fibres, as assessed by the coagulation assay. Fibrinogen and bilirubin interact at physiological concentrations, bilirubin may act as an antioxidant for fibrinogen and may modulate an important event in haemostasis, which altogether suggests possible physiological relevance of this interaction.

Effect of ZnO on Mechanical and Electrical Properties of Peroxide Cured EPDM

This paper presents reduction of ZnO in EPDM formulations and its influence on efficiency of cable isolation by measuring cure behavior, electrical and mechanical properties before and after ageing. These experiments were performed on EPDM formulations by changing three key variables in formulation (concentration of ZnO, type of peroxide and content of ethylene in EPDM). The rheological characterization showed that replacing ZnO in EPDM with proper ethylene content (75 %) with the lower content of ZnO (5 phr) in the recipes, resulted in lower cure time and higher scorch time and higher crosslinking density, which was further supported by Fourier transform infrared spectroscopy (FTIR). Mechanical properties before aging (elongation at break, tensile strength, and hardness) are greater with smaller content of ZnO. The value of percentage change of the properties after aging at 135 °C for 7 days, indicates that recipe D (Perkadox 14/40 (Di (tert-butyl peroxy isopropyl) benzene (DTBPIB)) peroxide cured EPDM has the best performance at tensile strength, and elongation at break. What is more, recipe D, containing 5 phr of ZnO exhibits the desired electrical performance. The paper provides sufficient experimental background to indentify the key physical aspects associated with each of the instabilities that occur at higher amounts of ZnO in formulation, and this in turns provides insight into different occurrences of each instability and how they can be minimized by reduction of ZnO in EPDM mixture.

Clozapine, ziprasidone, and sertindole-induced morphological changes in the rat heart and their relationship to antioxidant enzymes function

Atypical antipsychotics produce severe side effects including myocarditis that may be attributed to oxidative stress. The aim of this study was to investigate the influence of clozapine, ziprasidone, and sertindole on rat heart morphology and determine whether redox imbalane plays a role in development of histopathological changes. Adult 3-month-old male Wistar rats were treated with recommended daily dose for selected drugs. After 4 week treatment histopathological analysis of the heart was performed and expression and activity of antioxidant enzymes determined. All examined drugs induced histopathological changes that were characterized as toxic myocarditis. Degenerative changes in cardiomyocytes were accompanied by lymphocytic infiltration as well as pericardial histopathological alterations in all treated groups. The least prominent changes were observed in sertindole-treated animals, and most severe with clozapine. Clozapine increased superoxide dismutase 1 (SOD1) activity while ziprasidone reduced glutathione reductase (GR) activity. Sertindole exerted no marked effect on antioxidant enzyme function in the heart even though myocardial degeneration was noted. In conclusion, treatment with clozapine or ziprasidone induced pathophysiological alterations in rat heart, which appeared to be associated disturbances in antioxidant capacity. Abbreviation: AAP, Atypical antipsychotics; ROS, reactive oxygen species; SOD1, Copper-zinc superoxide dismutase; SOD2, Manganese superoxide dismutase; CAT, Catalase; GPx, Glutathione peroxidase; GR, Glutathione reductase; H&E, hematoxylin and eosin stain; TNF- α, tumor necrosis factor alpha.

Selenazolyl-hydrazones as Novel Selective MAO Inhibitors With Antiproliferative and Antioxidant Activities: Experimental and In-silico Studies

The novel approach in the treatment of complex multifactorial diseases, such as neurodegenerative disorders and cancer, requires a development of efficient multi-targeting oriented drugs. Since oxidative stress significantly contributes to the pathogenesis of cancer and neurodegenerative disorders, potential drug candidates should possess good antioxidant properties. Due to promising biological activities shown for structurally related (1,3-thiazol-2-yl)hydrazones, a focused library of 12 structurally related benzylidene-based (1,3-selenazol-2-yl)hydrazones was designed as potential multi-targeting compounds. Monoamine oxidases (MAO) A/B inhibition properties of this class of compounds have been investigated. Surprisingly, the p-nitrophenyl-substituted (1,3-selenazol-2-yl)hydrazone 4 showed MAO B inhibition in a nanomolar concentration range (IC₅₀ = 73 nM). Excellent antioxidant properties were confirmed in a number of different in vitro assays. Antiproliferative activity screening on a panel of six human solid tumor cell lines showed that potencies of some of the investigated compounds was comparable or even better than that of the positive control 5-fluorouracil. In-silico calculations of ADME properties pointed to promising good pharmacokinetic profiles of investigated compounds. Docking studies suggest that some compounds, compared to positive controls, have the ability to strongly interact with targets relevant to cancer such as 5′-nucleotidase, and to neurodegenerative diseases such as the small conductance calcium-activated potassium channel protein 1, in addition to confirmation of inhibitory binding at MAO B.

Effects of antipsychotic drug administration on antioxidative defense enzymes in male rat kidney

The use of atypical antipsychotic drugs (APD) was reported to be associated with adverse effects on the kidneys. Thus, the aim of this study was to examine whether APD exerted their adverse effects by interfering with the renal antioxidant defense system. Male 3-mo-old Wistar rats were treated for 28 d with ziprasidone (ZIP), clozapine (CLO), or sertindole (SER) using a daily dose recommended for antipsychotic drug therapy. The expression and activities of antioxidant enzymes superoxide dismutase (SOD) type 1 and type 2, catalase (CAT), glutathione reductase (GR), and glutathione S-transferases (GSTs) activity were measured in the kidneys. Changes in the kidneys were also evaluated histologically. Ziprasidone, CLO, and SER reduced renal SOD type 1 and type 2 activities. Decreased CAT activity was observed only in SER-treated rats. An inhibition in GR activity and increased activity of GST was found only after treatment with CLO. Histological analysis showed dilatation of proximal tubules in kidneys with all three drugs. In conclusion, data indicate that redox disturbances may contribute to renal morphologic alterations in proximal tubules in rats treated with all APD.

[APPROACH TO PATIENTS WITH GASTROINTESTINAL BLEEDING]

In the developed Western countries, despite the accumulation of knowledge about the causes and treatment of gastrointestinal bleeding, as well as the experience of gastroenterologists-endoscopists using sophisticated endoscopic devices, the number of hospitalizations and mortality rates has not declined as expected. The most likely explanations are the following: aging population, increased prevalence of alcoholic liver cirrhosis, gastroesophageal reflux disease and obesity, Helicobacter pylori antibiotic resistance, using dual anti-aggregation therapy, anticoagulants, and excessive use of nonsteroidal anti-inflammatory drugs. The aim of this paper is to show the incidence and the most common signs and symptoms of gastrointestinal bleeding. The aim is also to present initial clinical evaluation, diagnostic methods, the main causes of gastrointestinal bleeding, endoscopic hemostatic modalities and treatment of bleeding from the upper and lower gastrointestinal tract. Using the MEDLINE and Ovid databases, we searched the meta-analyses and systematic reviews published in English during the 2005-2015 period. Meta-analyses included results of randomized, double-blind studies on adults treated for gastrointestinal bleeding. Included were guidelines of the European and American Society of Gastroenterological Endoscopy, as well as recent expert work. In this review, we bring the state-of-the-art on gastrointestinal bleeding, new classification of gastrointestinal bleeding from the upper, mid and lower gut, controversy of nasogastric tube placement, use of prokinetic agents and inhibitor proton pumps in acute gastrointestinal bleeding from the upper tract, restrictive transfusion strategy, useful clinical stratification of the severity of bleeding, indications for hospitalization and outcome of using the clinical bleeding score, proper use of gastroprotection in patients at a high risk of peptic ulcer, the need of initial endoscopy, variceal assessment in newly diagnosed liver cirrhosis, primary and secondary prophylaxis of variceal bleeding, new endoscopic hemostatic modality, and radiological and surgical treatment of gastrointestinal bleeding. The educational nature of this review could serve for establishing Croatian guideline for the management of gastrointestinal bleeding.

Multiple signal classification for self-mixing flowmetry

For the first time to our knowledge, we apply the multiple signal classification (MUSIC) algorithm to signals obtained from a self-mixing flow sensor. We find that MUSIC accurately extracts the fluid velocity and exhibits a markedly better signal-to-noise ratio (SNR) than the commonly used fast Fourier transform (FFT) method. We compare the performance of the MUSIC and FFT methods for three decades of scatterer concentration and fluid velocities from 0.5 to 50 mm/s. MUSIC provided better linearity than the FFT and was able to accurately function over a wider range of algorithm parameters. MUSIC exhibited excellent linearity and SNR even at low scatterer concentration, at which the FFT's SNR decreased to impractical levels. This makes MUSIC a particularly attractive method for flow measurement systems with a low density of scatterers such as microfluidic and nanofluidic systems and blood flow in capillaries.

Effect of the optical system on the Doppler spectrum in laser-feedback interferometry

We present a comprehensive analysis of factors influencing the morphology of the Doppler spectrum obtained from a laser-feedback interferometer. We explore the effect of optical system parameters on three spectral characteristics: central Doppler frequency, broadening, and signal-to-noise ratio. We perform four sets of experiments and replicate the results using a Monte Carlo simulation calibrated to the backscattering profile of the target. We classify the optical system parameters as having a strong or weak influence on the Doppler spectrum. The calibrated Monte Carlo approach accurately reproduces experimental results, and allows one to investigate the detailed contribution of system parameters to the Doppler spectrum, which are difficult to isolate in experiment.

RELACIJE IZMEĐU GLOBE DIMENZIJA ORGANIZACIONE KULTURE I EMOCIONALNE INTELIGENCIJE ZAPOSLENIH U SRPSKIM ORGANIZACIJAMA

Jedna od karakteristika savremenih organizacija je stalna potrebaza promenama njihove organizacione kulture kao odgovor nadinamično organizaciono okruženje. Ova potreba je posebnoizražena u zemljama u tranziciji koje nisu bile pripremljene na oštrutržišnu utakmicu. Stoga brojni istraživači ispituju antecedentespremnosti na promene posebno menadžera u organizacijamakoji u najvećoj meri kreiraju organizacionu kulturu. Istraživanjaorganizacione kulture u zemljama u tranziciji zasnovana naprojektu GLOBE-a ukazala su na postojanje takozvanog„pendulum efekta” odnosno statistički značajne razlike izmeđupercipirane organizacione kulture i poželjne organizacione kulturemenadžera u organizacijama. Ovi rezultati ukazuju na „loše”fitovanje ličnosti i organizacije u tranzicionim zemljama uzimajućiu obzir činjenicu da su organizacione vrednosti, izražene krozpoželjnu organizacionu kulturu, važan deo ukupnog vrednosnogsistema menadžera. Prisustvo diskrepancije između percipiranei poželjne organizacione kulture smanjuje zadovoljstvoposlom, kvalitet radnih performansi i organizacionu privrženosta povećava verovatnoću da najbolji menadžeri napusteorganizaciju. Istraživanja su pokazala da su emocionalnointeligentni menadžeri najbolji „agenti” organizacionih promenai stoga je od naučnog i praktičnog interesa istražiti u kojoj jemeri emocionalna inteligencija prediktor željene organizacionekulture. Osnovni cilj našeg istraživanja je da se utvrdi u kojojmeri je emocionalna inteligencija prediktor željene organizacionekulture prema modelu GLOBE-ovog projekta. Projekat GLOBE(Globalno liderstvo i efektivnost organizacionog ponašanja) jedvadesetogodišnji projekat koji je okupio istraživače iz 62 zemljea istraživanje je obuhvatilo 18000 menadžera. Srbija nije bilauključena u ovaj projekat i ovo je jedno od prvih istraživanja unašoj zemlji koje treba da popuni ovu prazninu. Višegodišnjim istraživanjem učesnika u projektu GLOBE je identifikovano 9dimenzija organizacione kulture, među kojima su i one koje uodređenoj meri uopštavaju poznate dimenzije organizacionekulture uvedene od strane Hofstedea. Uzorak našeg istraživanjačini 224 srednjih menadžera iz 131 organizacije u Srbiji a rezultatipokazuju da ovi menadžeri preferiraju niži stepen distance moćii viši stepen orijentacije ka performansama, ka ljudima, kabudućnosti, izbegavanja neizvesnosti i institucionalnog i grupnogkolektivizma. Hijerarhijska regresiona analiza je pokazalada je upravljanje emocijama najbolji prediktor izbegavanjaneizvesnosti, samomotivacija je najbolji prediktor orijentacije kabudućnosti, upravljanje emocijama i samomotivacija su najboljiprediktori institucionalnog kolektivizma, empatija i samosvestsu najbolji prediktori performansne orijentacije, pol, samosvesti socijalne sposobnosti su najbolji prediktori organizacioneravnopravnosti polova a samomotivacija je najbolji prediktorasertivnosti. Dobijeni rezultati mogu biti korišćeni prilikomorganizacionih promena koje treba da pomognu u zadržavanjuemocionalno inteligentnih menadžera i razvoju njihove karijere,kao i prilikom selekcije menadžera.

Solving self-mixing equations for arbitrary feedback levels: a concise algorithm

Self-mixing laser sensors show promise for a wide range of sensing applications, including displacement, velocimetry, and fluid flow measurements. Several techniques have been developed to simulate self-mixing signals; however, a complete and succinct process for synthesizing self-mixing signals has so far been absent in the open literature. This article provides a systematic numerical approach for the analysis of self-mixing sensors using the steady-state solution to the Lang and Kobayashi model. Examples are given to show how this method can be used to synthesize self-mixing signals for arbitrary feedback levels and for displacement, distance, and velocity measurement. We examine these applications with a deterministic stimulus and discuss the velocity measurement of a rough surface, which necessitates the inclusion of a random stimulus.

Self-mixing laser Doppler flow sensor: an optofluidic implementation

We present the miniaturization of self-mixing interferometry (SMI) into a microfluidic circuit using an optical fiber, forming an optofluidic device that can be used as a component in lab on a chip systems. We characterize the performance of the device as a fluid velocity (and hence flow) sensor, showing it to produce good accuracy and correlation with theory over a range of velocities from 0.5 to 60  mm/s and almost four decades of scatterer concentration. SMI in an optofluidic system has the advantage that only a single path to the optical inspection point is needed, as the laser source is also the receiver of light. In addition, the same system that is used for measuring fluid velocity can be used to measure other quantities such as particle size. The configuration presented is inherently easy to optically align due to the self-aligned property of SMI and divergent nature of light exiting the embedded optical fiber, providing for low-cost manufacturing.

Approach to frequency estimation in self-mixing interferometry: multiple signal classification

Based on the nature of self-mixing signals, we propose the use of the multiple signal classification (MUSIC) algorithm in place of the fast Fourier transform (FFT) for processing signals obtained from self-mixing interferometry (SMI). We apply this algorithm to two representative SMI measurement techniques: range finding and velocimetry. Applying MUSIC to SMI range finding, we find its signal-to-noise ratio performance to be significantly better than that of the FFT, allowing for more robust, longer-range measurement systems. We further demonstrate that MUSIC enables a fundamental change in how SMI Doppler velocity measurement is approached, letting one discard the complex fitting procedure and allowing for a real-time frequency estimation process.

Effect of atypical antipsychotics on antioxidant enzyme activities in human erythrocytes (in vitro study)

OBJECTIVE

This study was set out to examine the impact of atypical antipsychotic drugs: aripiprazole, clozapine, ziprasidone, olanzapine, quetiapine, sertindole and amisulpride on the activity of antioxidant defence enzymes in human erythrocytes in vitro.

METHODS

Cu,Zn-superoxide dismutase (SOD1), catalase (CAT), selenium-dependent glutathione peroxidase and glutathione reductase activities were determined after drugs incubation with blood of 15 apparently healthy non-smoking male volunteers (ages 23-39) for 1 h at 37 °C.

RESULTS

A statistically significant increase in SOD1 activity was found in samples incubated with aripiprazole (p < 0.01) and quetiapine (p < 0.05) compared with incubated control. SOD1 activity profile following native polyacrylamide gel electrophoresis indicates that aripiprazole and quetiapine protect enzyme activity from inhibition with hydrogen peroxide. Our results showed that sertindole decreases activity of CAT comparing with control non-treated erythrocytes. Moreover, in sertindole treated erythrocytes, negative correlation between SOD1 and glutathione peroxidase activities was found. Increased amount of hydrogen peroxide in such situation may leave erythrocytes and transform their role in circulation from anti-oxidative to pro-oxidative.

CONCLUSIONS

Our results indicate that mechanism through sertindole could express its in vivo toxic effects and point toward possible (neuro)protective effects of aripiprazole and quetiapine.