Theory of Exciton Migration and Field-Induced Dissociation in Conjugated Polymers

The interplay of migration, recombination, and dissociation of excitons in disordered media is studied theoretically in the low temperature regime. An exact expression for the photoluminescence spectrum is obtained. The theory is applied to describe the electric field-induced photoluminescence-quenching experiments by Kersting et al. [Phys. Rev. Lett. 73, 1440 (1994)] and Deussen et al. [Synth. Met. 73, 123 (1995)] on conjugated polymer systems. Good agreement with experiment is obtained using an on-chain dissociation mechanism, which implies a separation of the electron-hole pair along the polymer chain.Comment: 4 pages, RevTeX, 2 Postscript figure

Theory of Electric Field-Induced Photoluminescence Quenching in Disordered Molecular Solids

The dynamics of excitons in disordered molecular solids is studied theoretically, taking into account migration between different sites, recombination, and dissociation into free charge carriers in the presence of an electric field. The theory is applied to interpret the results of electric field-induced photoluminescence (PL) quenching experiments on molecularly doped polymers by Deussen et al. [Chem. Phys. 207, 147 (1996)]. Using an intermolecular dissociation mechanism, the dependence of the PL quenching on the electric field strength and the dopant concentration, and the time evolution of the transient PL quenching can be well described. The results constitute additional proof of the distinct exciton dissociation mechanisms in conjugated polymer blends and molecularly doped polymers.Comment: 4 pages RevTeX, 3 Postscript figure

Functional, morphologic, and molecular characterization of cold storage injury

ObjectiveCold storage is used to preserve tissue for later transplantation. There is particular interest in prolonging cold storage time for transplantation purposes. To date, the mechanisms that contribute to vascular dysfunction in response to cold storage are poorly understood. The present study aims to characterize cold storage injury of blood vessels on functional and molecular levels.MethodsTo assess vessel function of mouse aorta, isometric force measurements were performed in a Mulvany myograph after cold storage at 4°C for various intervals. Morphologic changes were judged by histologic analysis of aortic cross-sections. To characterize cold storage-induced alterations on RNA levels, microarray analysis with subsequent polymerase chain reaction analysis was performed.ResultsCold storage for 2 days revealed significant impairment of vessel function with respect to potassium-induced vessel tone development and acetylcholine-induced vessel relaxation. Detailed analysis of acetylcholine-mediated vascular response using specific pharmacologic blockers revealed that calcium-activated potassium channels seem to be impaired after 2 days of cold storage. At this point, no severe histologic changes (eg, elastic fiber disruption) were visible. RNA expression of 24 genes was significantly changed due to cold storage even after 2 hours. These include genes associated with vessel tone development (prostaglandin E3 receptor), cardiovascular function (adiponectin), electron transport chain (uncoupling protein 1), or calcium signaling (protein kinase A regulatory subunit 2b).ConclusionsLong-term cold storage impairs vascular function, especially with respect to potassium signaling by calcium-dependent potassium channels. Microarray analysis confirmed impairment of pathways that are involved in calcium signaling and vascular function. Furthermore, various genes were significantly altered even after 2 hours, significantly before functional impairment was observed.Clinical RelevanceIn bypass surgery, vessels are stored ex situ for <2 hours and for vessel banking for up to 48 hours during decontamination before cryopreservation. We investigated the onset of storage-induced alterations. The experiments reveal various genes were altered significantly, even within the first 2 hours of cold storage. This is of major importance, because of the time delay between regulation of messenger RNA and protein level and functional consequences. The alterations described here on the molecular level occur before any alterations on morphologic or functional levels are obvious. These molecular alterations, however, may affect later graft function

Metformin and dietary advice to improve insulin sensitivity and promote gestational restriction of weight among pregnant women who are overweight or obese: the GRoW Randomised Trial

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background Obesity is a significant global health problem, with approximately 50% of women entering pregnancy having a body mass index greater than or equal to 25 kg/m2. Obesity during pregnancy is associated with a well-recognised increased risk of adverse health outcomes both for the woman and her infant. Currently available data from large scale randomised trials and systematic reviews highlight only modest effects of antenatal dietary and lifestyle interventions in limiting gestational weight gain, with little impact on clinically relevant pregnancy outcomes. Further information evaluating alternative strategies is required. The aims of this randomised controlled trial are to assess whether the use of metformin as an adjunct therapy to dietary and lifestyle advice for overweight and obese women during pregnancy is effective in improving maternal, fetal and infant health outcomes. Methods Design: Multicentre randomised, controlled trial. Inclusion Criteria: Women with a singleton, live gestation between 10+0-20+0 weeks who are obese or overweight (defined as body mass index greater than or equal to 25 kg/m2), at the first antenatal visit. Trial Entry & Randomisation: Eligible, consenting women will be randomised between 10+0 and 20+0 weeks gestation using an online computer randomisation system, and randomisation schedule prepared by non-clinical research staff with balanced variable blocks. Stratification will be according to maternal BMI at trial entry, parity, and centre where planned to give birth. Treatment Schedules: Women randomised to the Metformin Group will receive a supply of 500 mg oral metformin tablets. Women randomised to the Placebo Group will receive a supply of identical appearing and tasting placebo tablets. Women will be instructed to commence taking one tablet daily for a period of one week, increasing to a maximum of two tablets twice daily over four weeks and then continuing until birth. Women, clinicians, researchers and outcome assessors will be blinded to the allocated treatment group. All women will receive three face-to-face sessions (two with a research dietitian and one with a trained research assistant), and three telephone calls over the course of their pregnancy, in which they will be provided with dietary and lifestyle advice, and encouraged to make change utilising a SMART goals approach. Primary Study Outcome: infant birth weight >4000 grams. Sample Size: 524 women to detect a difference from 15.5% to 7.35% reduction in infants with birth weight >4000 grams (p = 0.05, 80% power, two-tailed). Discussion This is a protocol for a randomised trial. The findings will contribute to the development of evidence based clinical practice guidelines

Features of adenosine metabolism of mouse heart

Adenosine metabolism and transport were evaluated in the isolated perfused mouse heart and compared with the well-established model of isolated perfused guinea pig heart. Coronary venous release of adenosine under well-oxygenated conditions in the mouse exceeds that in the guinea pig threefold when related to tissue mass. Total myocardial adenosine production rate under this condition was approximately 2 nmol/min per gramme and similar in both species. Coronary resistance vessels of mice are highly sensitive to exogenous adenosine, and the threshold for adenosine-induced vasodilation is approximately 30 nmol/l. Adenosine membrane transport was largely insensitive to nitrobenzyl-thioinosine (NBTI) in mouse heart, which is in contrast to guinea pig and several other species. This indicates the dominance of NBTI-insensitive transporters in mouse heart. For future studies, the assessment of cytosolic and extracellular adenosine metabolism and its relationship with coronary flow will require the use of more effective membrane transport blockers

Анализ современных технологий заводнения при разработке нефтяных месторождений

Объектом исследования являются системы заводнения применяемые на месторождениях России Цель работы – анализ современных технологий заводнения при разработке нефтяных месторождений, а также обоснование применения технологий заводнения с целью увеличения темпов отбора, коэффициента нефтеизвлечения, технико-экономических показателей. В выпускной квалификационной работе приведены сведения о современных технологиях заводнения, применяемых на месторождениях России. Проведены расчеты экономической эффективности при внедрении нестационарного метода заводнения. Проанализирован процесс работы методов заводнения в условиях месторождений России. Бакалаврская работа выполнена в текстовом редакторе Microsoft Word, и Microsoft Excel.The object of the study are the waterflooding systems used in the fields of Russia The aim of the work is the analysis of modern flooding technologies in the development of oil fields, as well as the rationale for using flooding technologies to increase the rate of selection, the oil recovery factor, and the technical and economic indicators. In the final qualification work information on modern water flooding technologies used in the fields of Russia is given. Calculations of economic efficiency are implemented in the introduction of the non-stationary flooding method. The process of work of flooding methods in the conditions of Russian deposits is analyzed. Bachelor's work is executed in the text editor Microsoft Word, and Microsoft Excel

Evelopment of the model of diagnosis of the risk of bankruptcy

The article presents an overview of foreign and domestic models for the diagnosis of bankruptcy risk, and gives a brief description of them. Also considered the development of our own model of bankruptcy risk diagnostics for Russian enterprise

Modeling and generating moving trees from video

We present a probabilistic approach for the automatic production of tree models with convincing 3D appearance and motion. The only input is a video of a moving tree that provides us an initial dynamic tree model, which is used to generate new individual trees of the same type. Our approach combines global and local constraints to construct a dynamic 3D tree model from a 2D skeleton. Our modeling takes into account factors such as the shape of branches, the overall shape of the tree, and physically plausible motion. Furthermore, we provide a generative model that creates multiple trees in 3D, given a single example model. This means that users no longer have to make each tree individually, or specify rules to make new trees. Results with different species are presented and compared to both reference input data and state of the art alternatives

Технологические решения для реконструкции добывающей скважины глубиной 2170 метров методом зарезки бокового ствола на нефтяном месторождении Томской области

Обоснование технологических решений для реконструкции добывающей скважины глубиной 2170 метров методом зарезки бокового ствола на нефтяном месторождении Томской области. В процессе исследования проводился анализ предоставленных геологических данных для принятия решений при разработке проекта. В результате исследования представлен комплекс технологических решений для строительства бокового ствола. Основные конструктивные, технологические и технико-эксплуатационные характеристики: обоснование и расчет профиля бокового ствола, расчет процессов углубления и заканчивания скважины, определение времени и стоимости проведения работ. Область применения: работа может быть использованы при составлении проектов на скважины, а данные из специальной части – при разработке состава эластомера ВЗД.Substantiation of technological solutions for reconstruction of a production well with a depth of 2,170 meters by the method of sidetracking at an oil field in the Tomsk region. In the course of the study, the analysis of the provided geological data for decision making during project development was carried out. As a result of the research, a set of technological solutions for the construction of the lateral trunk is presented. The main design, technological and technical and operational characteristics: justification and calculation of the sidetrack profile, calculation of the deepening and completion of the well, determination of the time and cost of work. Scope: the work can be used in the design of wells, and data from a special part - when developing the composition of an elastomer