Photoactivation mechanism of DNA photolyase

This presentation is on the theoretical computational study of the DNA photolyase from E. coli. Continuum electrostatic method [4] is employed to get a full insight into the photoactivation mechanism of the enzyme. Protonation state of titratable residues, the redox potentials of tryptophan triad, energetics and the reaction rates are calculated and compared with available experimental data. The free energies of all potentially relevant states for the radical transfer during the photoactivation process are evaluated

Energetics of the steps in proton pumping mechanism and preventing of backflow reactions in cytochrome c oxidase

Cytochrome c oxidase (CcO) is the terminal enzyme of aerobic respiration, which is responsible for processing most of the biological oxygen and generating electrochemical proton gradient in aerobic cells [1]. The energy released from the reduction of molecular oxygen to water is used to pump protons across the mitochondrial or bacterial membrane. The structure of the enzyme has been solved for several organisms; however details of its molecular mechanism of proton pumping still remain elusive. Recent time-resolved optical and electrometric experiments on the O E transition have suggested a sequence of reaction steps for the proton-translocation mechanism of CcO [2]. The pump function introduces a mechanistic requirement of a valve that prevents protons from flowing backwards during the process. It was recently found that Glu242, a key amino acid in transferring protons to be pumped across the membrane and to the site of oxygen reduction, fulfills the function of such a valve by preventing simultaneous contact to the pump site and to the proton-conducting D-channel [3, 4]. Here we have included the conformational gating by Glu242 into the framework of the proposed His291 pumping model [5]. DFT/electrostatic calculations are employed to obtain energetics of proton and electron transfer reaction steps during the O E transition, while transition state theory is used for estimating activation energies and kinetic barriers from the rate constant of transitions. The energy profile of the reaction mechanism is studied by exploring how the redox state of the adjacent metal centers, dielectric effects, and membrane potential gradient, affect the energy levels and the leaks of the Glu-valve. Special emphasis is made on side-reactions that may short-circuit the pump, and the means by which these may be avoided. The state with the proton on the pump site (His291) is especially vulnerable to leak back to Glu instead of being released to the P- side of the membrane, what would result in a loss of proton-pumping. Obviously, there are more different control mechanisms and gating situations employed by the enzyme to ensure the unidirectionality of the proton translocation and to prevent proton leak in the opposite direction

Mission critical ICT

In this paper, three technologies intended to be implemented in Private Mobile Radio systems are analyzed and compared: TETRA (Terrestrial Trunked Radio), LTE (Long Term Evolution) and DMR (Digital Mobile Radio). Characteristics of these networks are collected and compared in one SWOT table. Based on this analysis, appropriate recommendations are made, which should be taken into account when choosing a specific solution for specific uses in Critical Communications systems

Vreli dalmatinski srpanj 1989.

U radu se analiziraju događaji iz srpnja/jula 1989. u Dalmaciji, koji su imali veliki uticaj na srpsko-hrvatske odnose (i posledično na celu Jugoslaviju). Rad će pokazati kako se u samo jednom mesecu jasno uočavaju: pravci razvoja jugoslovenske krize, lančana reakcija do koje dovodi eksplozija srpskog nacionalizma krajem 1980-ih, rušenje tzv. hrvatske šutnje i promena u medijskom izveštavanju važnog regionalnog lista – Slobodne Dalmacije. Dalmacija će tog meseca, nakon svojevrsnog nastavka gazimestanskog skupa na dalmatinskom Kosovu, postati poprište desetina incidenata na nacionalnoj osnovi koji će biti korišćeni od strane srpskih i hrvatskih nacionalista da se zavrti spirala mržnje i da se osvoji, tj. učvrsti vlast političkih elita u Zagrebu i Beogradu. Protagonisti “hrvatske šutnje” počišćeni su sa političke scene, a posebna sednica CK SKJ posvećena nacionalnim odnosima, održana krajem istog meseca, i simbolički je označila kraj iluzije o moći savezne partije da stane na put razbuktalom nacionalizmu. Sve je bilo spremno da nastupe 1990-e

Прилог убикације Батоновог логора

Angaben aus schriftlichen Quellen und archäologischen Forschungen auf Mala und Velika Gradina bei Lezimir lassen die Möglichkeit der Ubikation von Batons Lager an diesem Ort zu. Die Stratigraphie und die Rettungsausgrabungen zeigen, daß das Leben auf Gradina trotz der Monumentalität der Fortifikation von kurzer Dauer war. Die, der Zahl nach bescheidenen, keramischen Funde gehören dem Ende der älteren Eisenzeit (Bosut III c) an. der Zeit also, als in diesen Regionen die Stämme der Amantinen und Breucen lebten

Protein environment – cofactor interactions in redox protein systems

The interactions between the enclosed protein environment and cofactors are crucial in understanding redox protein systems. The redox potential (Em) is a key parameter of all redox active proteins and is easily accessible in experimental and computational studies. By advanced computational methods, this research examined in-depth the complex relationship between a confined protein system and its cofactor within a bioinspired protein scaffold and found multiple contributing factors. The Em values were dissected to identify interactions in heme proteins that contribute to various energy terms.Invited talk, lecture L

Purification of waters and elimination of organochloric insecticides by means of active coal

Pollution of water and the determination of the degree of its pollution with numerous physical, chemical and biological polluters have become general, ever increasing social and health related problems. Within this study, the concentrations of some most frequently used organochloric insecticides (OCI): a-hexachlorocyclohexane (a-HCH), γ-hexachlorocyclohexane (lindane), heptachlor, aldrin, dieldrin, endrin, dichlorodiphenyl trichlorethane (DDT) were investigated. OCI are highly toxic substances for the human population and their effective elimination from the environment is of paramount interest. To determine the OCI concentration in water samples, the EPA–608 method and the liquid–liquid extraction principle were applied. A procedure for OCI elimination was realized by passing the water over four columns filled with various active coals: KRF, K-81/B, NORIT ROW-0.8 and AQUA SORB CS. These active coals are carbonized coconut shells activated by different procedures. The obtained results indicated that best purification of potable and waste water achieved using a column with Norit Row-0.8 filling. Research proved that small quantities of OCI can also be effectively removed using a Norit Row-0.8 active coal filled column, without altering the organoleptic properties of the water, which meets the requirements of water purification processes

Megaendoprosthesis in the treatment of bone tumors in the knee and hip region

Background/Aim. For almost two decades extremity amputation has not been the only viable option for patients with from bone cancer in the region of the hip and knee. Remarkable advances in implant technology, surgical reconstructive technique and adoption of new chemotherapy protocols provide a new option for surgeons who diagnose and treat bone tumors. Megaendoprosthesis has become widely accepted alternative in limb salvage surgery of the extremities. The aim of this study was to present an outcome of the treatment of bone tumors in the knee and hip region by the use of custom made megaendoprothesis. Methods. In the period 2006-2008 we adopted new clinical practice protocols for preoperative management in candidates for tumor megaprostheses of the hip and knee including: surgical tumor staging, histopathological verification, determinants of anatomical-mechanical defect, status of soft tissues, CT evaluation of the referent measures of pelvis, femur and tibia necessary for creation of custom made endoprosthesis and surgery plan, as well as modern, less invasive surgical approach. The patients were monitored during ≥ 24 months after the surgery for detecting possible complications. Results. All procedures were performed without complications during and immediately after the surgery. During the follow-up period not less than 24 months we failed to record any significant complications. Conclusion. Custom made megaendoprosthesis are the method of choice in the treatment of bone tumors in the region of the hip and knee at the Orthopedics and Traumatology Clinic, Military Medical Academy, Belgrade. The greatest challenge - ensuring longevity of a prosthesis can be achieved not only by prevention of common complications of arthroplasty procedures but, certainly, with the introduction of new methods for preoperative planning - computer-assisted technique of measuring referent sizes and software solutions for the selection and design of custom-made components of an endoprosthesis

The model of the life insurance process quality improvement

Osnovni cilj istraživanja u ovoj doktorskoj disertaciji je da se analizom stanja na tržištu osiguranja, stavova potencijalnih korisnika životnog osiguranja i menadžmenta osiguravajućih kompanija, kao i studijom slučaja konkretne, složene osiguravajuće kompanije, razvije model unapređenja kvaliteta procesa životnog osiguranja i razrade osnovni strateški elementi, a odnose se na planiranje, organizaciju i upravljanje sistemima koji pružaju usluge životnog osiguranja. Primjenom metoda ankete i intervjua i modela Balanced Scorecard, uočeni su kritični elementi poslovnih procesa i predložene mjere unapređenja. Razvijen je model kompanije koja posluje u oblasti životnog osiguranja koji obezbjeđuje njenu samostalnost, uključuje aktuelna ograničenja na evropskom tržištu osiguranja i povišenu efektivnost njenih poslovnih procesa.The main goal of this doctoral dissertation is to develop a model for improving the quality of life insurance process and to elaborate basic strategic elements such as planning, organization and management of institutions that provide life insurance services. This is achieved through analysis of the life insurance market, attitudes of potential customers and the management of insurance companies, as well as a case study of concrete, complex life insurance company. Through application of the survey method, interview, as well as balanced scorecard, the critical business process elements were noted and improvement measures were proposed. As a result, a model which ensures the independence of the life insurance company, includes current restrictions at the European insurance market and enables increased efficiency of its business processes, was developed