Elektronų paramagnetinio rezonanso metodo taikymas.

The article describes the results of the original investigations of the gravel mine detection using the modern analysis method - electron paramagnetic resonance (EPR). In the investigation of the criminal offences the problem of the detection of the substances source of different objects is faced. Very often such substances could be an intermediate link between the crime scene investigated and a suspect or some kind of tools, transport means or other objects. The investigations executed broaden the investigation possibilities of gravel (sand) and the similar objects. This could be the basis for a new expertise investigation method and to serve for the forensic geology. The gravel EPR spectrum is modeled using the limestone and dolomite parts mixture. The lines of this spectrum are given by manganese, which got in to the limestone and dolomite grating as a natural impurity in the process of their formation. EPR spectrum depends not only on manganese (as impurity) but also how manganese ions interact with magnesium and calcium. Having admixed gravel with manganese salt a new EPR line is made (wide and in other magnetic field sphere) and former lines, which are given by magnesium being in the gravel do not change. To remove magnesium from the grating is possible only during the chemical reactions. The mathematic methodology is prepared which is suitable to determine from which mine (quarry) the unknown gravel was taken. The methodology is based on the countering of euclid distance between the appropriate EPR spectrum components. For the investigation is enough to have 50-100 mg of the substance (eliminating bigger than 2 mm of diameter parts). [...]Straipsnyje pateikti žvyro telkinio nustatymo taikant šiuolaikinį analizės metodą - elektronų paramagnetinį rezonansą (EPR) - originalių tyrimų rezultatai. Tiriant nusikalstamas veikas susiduriama su įvairių objektų, medžiagų šaltinio nustatymo problema. Tokios medžiagos neretai gali būti tarpinė grandie tarp tiriamos įvykio vietos ir įtariamojo arba tam tikrų įrankių, transporto priemonių ir kitų objektų. Mūsų atlikti tyrimai išplečia žvyro (smėlio) ir kitų panašių objektų tyrimo galimybes. Tai gali tapti naujos ekspertinės tyrimo metodikos pagrindu ir gali būti naudojama teismo geologijoje. Žvyro EPR spektras sumodeliuotas naudojant klinčių ir dolomitų dalelių mišinį. šio spektro linijas rodo manganas, kuris j klinčių ir dolomitų gardeles pateko kaip natūrali priemaiša šiems mineralams formuojantis. EPR spektras priklauso ne tik nuo mangano (kaip priemaišos) kiekio, bet ir nuo to, kaip mangano jonai sąveikauja su magniu ir kalciu. Primaišius į žvyrą mangano druskos gaunama nauja (plati ir kitoje magnetinio lauko srityje) EPR linija, o buvusios linijos, kurias rodo manganas, esantis gardelėje, nepasikeičia. Pašalinti manganą iš gardelės galima tik cheminių reakcijų metu. Parengta matematinė metodika tinkama nustatyti, iš kurio telkinio (karjero) buvo paimtas nežinomu tapęs žvyras. Metodika pagrįsta euklidinių nuotolių skaičiavimu tarp atitinkamų EPR spektro komponenčių. Tyrimui užtenka (atmetus didesnes kaip 2 mm skersmens daleles) apie 50-100 mg medžiagos. [...

Hypothesis: bacterial clamp loader ATPase activation through DNA-dependent repositioning of the catalytic base and of a trans-acting catalytic threonine

The prokaryotic DNA polymerase III clamp loader complex loads the β clamp onto DNA to link the replication complex to DNA during processive synthesis and unloads it again once synthesis is complete. This minimal complex consists of one δ, one δ′ and three γ subunits, all of which possess an AAA+ module—though only the γ subunit exhibits ATPase activity. Here clues to underlying clamp loader mechanisms are obtained through Bayesian inference of various categories of selective constraints imposed on the γ and δ′ subunits. It is proposed that a conserved histidine is ionized via electron transfer involving structurally adjacent residues within the sensor 1 region of γ's AAA+ module. The resultant positive charge on this histidine inhibits ATPase activity by drawing the negatively charged catalytic base away from the active site. It is also proposed that this arrangement is disrupted upon interaction of DNA with basic residues in γ implicated previously in DNA binding, regarding which a lysine that is near the sensor 1 region and that is highly conserved both in bacterial and in eukaryotic clamp loader ATPases appears to play a critical role. γ ATPases also appear to utilize a trans-acting threonine that is donated by helix 6 of an adjacent γ or δ′ subunit and that assists in the activation of a water molecule for nucleophilic attack on the γ phosphorous atom of ATP. As eukaryotic and archaeal clamp loaders lack most of these key residues, it appears that eubacteria utilize a fundamentally different mechanism for clamp loader activation than do these other organisms

A trimeric DNA polymerase complex increases the native replication processivity

DNA polymerases are essential enzymes in all domains of life for both DNA replication and repair. The primary DNA replication polymerase from Sulfolobus solfataricus (SsoDpo1) has been shown previously to provide the necessary polymerization speed and exonuclease activity to replicate the genome accurately. We find that this polymerase is able to physically associate with itself to form a trimer and that this complex is stabilized in the presence of DNA. Analytical gel filtration and electrophoretic mobility shift assays establish that initially a single DNA polymerase binds to DNA followed by the cooperative binding of two additional molecules of the polymerase at higher concentrations of the enzyme. Protein chemical crosslinking experiments show that these are specific polymerase–polymerase interactions and not just separate binding events along DNA. Isothermal titration calorimetry and fluorescence anisotropy experiments corroborate these findings and show a stoichiometry where three polymerases are bound to a single DNA substrate. The trimeric polymerase complex significantly increases both the DNA synthesis rate and the processivity of SsoDpo1. Taken together, these results suggest the presence of a trimeric DNA polymerase complex that is able to synthesize long DNA strands more efficiently than the monomeric form

The unstructured C-terminus of the τ subunit of Escherichia coli DNA polymerase III holoenzyme is the site of interaction with the α subunit

The τ subunit of Escherichia coli DNA polymerase III holoenzyme interacts with the α subunit through its C-terminal Domain V, τC16. We show that the extreme C-terminal region of τC16 constitutes the site of interaction with α. The τC16 domain, but not a derivative of it with a C-terminal deletion of seven residues (τC16Δ7), forms an isolable complex with α. Surface plasmon resonance measurements were used to determine the dissociation constant (KD) of the α−τC16 complex to be ∼260 pM. Competition with immobilized τC16 by τC16 derivatives for binding to α gave values of KD of 7 μM for the α−τC16Δ7 complex. Low-level expression of the genes encoding τC16 and τC16▵7, but not τC16Δ11, is lethal to E. coli. Suppression of this lethal phenotype enabled selection of mutations in the 3′ end of the τC16 gene, that led to defects in α binding. The data suggest that the unstructured C-terminus of τ becomes folded into a helix–loop–helix in its complex with α. An N-terminally extended construct, τC24, was found to bind DNA in a salt-sensitive manner while no binding was observed for τC16, suggesting that the processivity switch of the replisome functionally involves Domain IV of τ

Conserved residues in the δ subunit help the E. coli clamp loader, γ complex, target primer-template DNA for clamp assembly

The Escherichia coli clamp loader, γ complex (γ3δδ′λψ), catalyzes ATP-driven assembly of β clamps onto primer-template DNA (p/tDNA), enabling processive replication. The mechanism by which γ complex targets p/tDNA for clamp assembly is not resolved. According to previous studies, charged/polar amino acids inside the clamp loader chamber interact with the double-stranded (ds) portion of p/tDNA. We find that dsDNA, not ssDNA, can trigger a burst of ATP hydrolysis by γ complex and clamp assembly, but only at far higher concentrations than p/tDNA. Thus, contact between γ complex and dsDNA is necessary and sufficient, but not optimal, for the reaction, and additional contacts with p/tDNA likely facilitate its selection as the optimal substrate for clamp assembly. We investigated whether a conserved sequence—HRVW279QNRR—in δ subunit contributes to such interactions, since Tryptophan-279 specifically cross-links to the primer-template junction. Mutation of δ-W279 weakens γ complex binding to p/tDNA, hampering its ability to load clamps and promote proccessive DNA replication, and additional mutations in the sequence (δ-R277, δ-R283) worsen the interaction. These data reveal a novel location in the C-terminal domain of the E. coli clamp loader that contributes to DNA binding and helps define p/tDNA as the preferred substrate for the reaction

Clamp loader ATPases and the evolution of DNA replication machinery

Clamp loaders are pentameric ATPases of the AAA+ family that operate to ensure processive DNA replication. They do so by loading onto DNA the ring-shaped sliding clamps that tether the polymerase to the DNA. Structural and biochemical analysis of clamp loaders has shown how, despite differences in composition across different branches of life, all clamp loaders undergo the same concerted conformational transformations, which generate a binding surface for the open clamp and an internal spiral chamber into which the DNA at the replication fork can slide, triggering ATP hydrolysis, release of the clamp loader, and closure of the clamp round the DNA. We review here the current understanding of the clamp loader mechanism and discuss the implications of the differences between clamp loaders from the different branches of life

Recreational needs of businessmen during business travel

This work focuses on one type of tourism – business travel. The tourism sector plays an important role in the development of each country’s economy and is actively promoting its integration into the global market. 1998 – 2008 year is the fastest growing business travel markets period. The situation changed in the economic and tourism sector in 2008. In the final work analise the main concepts and classification of business travel, focus on recreational needs of business travelers. The object of this master is the recreatiniol needs of the business travelers. The main purpose – to analize the recreational needs of business travelers. The targets of this thesis are following: 1. To describe the conception, structure and trends of the business tourism. 2. To exclude recreational opportunities during business travel. 3. To find out the recreation needs of business travelers in “Trasalis - Trakai Resort & SPA” Center. The work consists of four main parts: the analysis of literature, the research and its results, recommendations and conclusion. Literature analysis presents the main concepts of business travel and recreation. It was done by analyzing foreign and Lithuanian authors studies and researches. After the literature analysis the author has made the research. In this research raised three hipothesis: H.1: Business travelers are in fact potential consumers of recreational services. H.2: The better organized a business traveler‘s leisure time, the better is his work during the trip. H.3: All recreational activities are relatively attractive to business travelers. In the work used the questionnaire survey method. The research problem is business traveler’s recreational needs. The questionnaire survey made in 2010 January – March in “Trasalis - Trakai Resort & SPA Center”. The respondents was this center conference participants used the hotel's services. The study distributed 110 questionnaires, of which - 94 were completed and returned (the return of questionnaires - 85 percent). The data is processing with the typical quantative data processing method Excel'2000 MS program. The results are presented in charts, tables, figures and percentage terms. The last part of thesis, Conclusions and Recommendations, summarize the results of the performed research. The results show that business travelers often quite enjoy recreational services during business travel. So business travelers understand the importance of recreation and agree that it is necessary to organize the rest - the time for recreation. The results showed that a large number of travelers do not focus on recreation opportunities in organizing a business trip. The recreational use may influence the stressful working agenda. And the current market it is important to plan not only working time, but also rest. Business travelers recreational needs the greatest influence do time and financial resources – there is factors thet influencing consumer behavior. Consumers are influenced by many factors such as: impact on the group, social class, culture. Consumer’s behavior depends on the things connected with his personality, occupation, lifestyle, social and cultural events. So most popular answer about the recreation type was nature and hobby; sport as recreational activities was chosen at least

Improving the quality of services at Dojus Agro company

Final work of master thesis consists of 60 pages, 5 tables, 25 references, 2 appendixes. Work is in Lithuanian language. Key words - service quality, storage service, quality improvement directions, servqual questionnaire. The object of the research is quality of services of DOJUS agro company. The aim of the research is to analyze the theoretical aspects of the improvement of service quality, to provide directions of improvement of the quality of services of DOJUS agro. Tasks of the master's thesis: To reveal the theoretical concept of service quality; Analyze the variety of service quality models and discuss the most appropriate models for evaluating the quality of the services of a company selling agricultural machinery; To investigate the quality of services of DOJUS agro; To provide quality improvement services for DOJUS agro UAB, which ensure development of the company's service spectrum. The research problem is the compliance of the expectations of the users of the services of UAB DOJUS agro with the quality of the services provided to them, evaluating the introduction of new services into the company's service package. Methods of research: Methods of systematic analysis and review of applied literature to reveal the theoretical part; in the analytical part the empirical method was used for the quantitative research - questionnaire survey according to SERVQUAL questionnaire; analysis of empirical research results. A mathematical method was used for statistical data processing. The results of the research: The situation in the analytical part of the work "Practical analysis of the situation" presents the company's activities, presents the internal and external environment of the company, discloses the service system, and examines the practical problem in full. The methodological part discusses the conceptions and development of the quality of the services, the models of service quality and the quality of the services are improved. There is also a detailed research stream and methodology. In the result part of the project part we describe the results of empirical research. Conclusions and suggestions are provided at the end of the work. The research found that the main practical problem is the too narrow attitude of the company's employees towards communication with clients (including potential clients), communication is not regular, targeted, oriented to the formation of clients' preliminary (preliminary) needs. The results of the master's thesis may have practical benefits, i.e. The direction of improvement of the services of DOJUS agro UAB can be applied in practical activities, not only by increasing the quality of the provided services, but also by involving new types of activities, the implementation of which would lead to the improvement of the quality of already performed services and at the same time increase of the company's income. On the basis of the results of the master's thesis, a report was prepared and presented at the scientific conference “Young Scientist”, 2019. April 11 at VDU Academy.Tyrimo objektas yra DOJUS žemės ūkio įmonės paslaugų kokybė. Tyrimo tikslas - išanalizuoti teorinius paslaugų kokybės gerinimo aspektus, teikti DOJUS agro paslaugų kokybės gerinimo kryptis. Magistro baigiamojo darbo užduotys: atskleisti teorinę paslaugų kokybės koncepciją; Išanalizuoti paslaugų kokybės modelių įvairovę ir aptarti tinkamiausius modelius, skirtus įvertinti žemės ūkio mašinų pardavimo įmonės paslaugų kokybę; Ištirti DOJUS agro paslaugų kokybę; Teikti DOJUS agro UAB kokybės gerinimo paslaugas, užtikrinančias įmonės paslaugų spektro plėtrą. Tyrimo problema - UAB „DOJUS“ paslaugų naudotojų lūkesčių atitikimas jiems teikiamų paslaugų kokybei, naujų paslaugų diegimo į bendrovės paslaugų paketą įvertinimas. Tyrimo metodai: sisteminės taikomosios literatūros analizės ir peržiūros metodai, atskleidžiantys teorinę dalį; analitinėje dalyje kiekybiniam tyrimui buvo naudojamas empirinis metodas - anketinė apklausa pagal SERVQUAL klausimyną; empirinių tyrimų rezultatų analizė. Statistiniam duomenų apdorojimui buvo naudojamas matematinis metodas. Tyrimo rezultatai: situacijos analizės dalyje „Praktinė situacijos analizė“ pateikiama įmonės veikla, pristatoma įmonės vidinė ir išorinė aplinka, atskleidžiama paslaugų sistema ir nagrinėjama visa praktinė problema. Metodologinėje dalyje aptariamos paslaugų kokybės koncepcijos ir plėtra, paslaugų kokybės modeliai ir paslaugų kokybė. Taip pat yra išsamus tyrimų srautas ir metodika. Projekto dalies rezultato dalyje aprašome empirinio tyrimo rezultatus. Darbo pabaigoje pateikiamos išvados ir pasiūlymai. Tyrimas parodė, kad pagrindinė praktinė problema yra pernelyg siauras įmonės darbuotojų požiūris į bendravimą su klientais (įskaitant potencialius klientus), komunikacija nėra reguliari, tikslinga, orientuota į klientų preliminarių (preliminarių) poreikių formavimą. Magistro baigiamojo darbo rezultatai gali turėti praktinės naudos, t. Y. DOJUS agro UAB paslaugų tobulinimo kryptis galima taikyti praktinėje veikloje ne tik didinant teikiamų paslaugų kokybę, bet ir įtraukiant naujų rūšių veiklą, kurios įgyvendinimas pagerintų kokybės lygį. jau atliktų paslaugų ir tuo pačiu metu didinant bendrovės pajamas. Remiantis magistro baigiamojo darbo rezultatais, parengta ir pristatyta mokslinė konferencija „Jaunoji mokslininkė“, 2019 m. Balandžio 11 d. VDU akademijoje.Bioekonomikos plėtros fakultetasVerslo ir kaimo vystymosi tyrimų instituta