Linear-fractional combinatorial optimization problems: model and solving

Euclidean problems of linear-fractional combinatorial optimization on arrangements are discussed. Authors propose the model of practical problem. Also the polynomial algorithm for solving linear-fractional combinatorial optimization problems on arrangements is discussed

About properties of linear stochastic optimization problems on arrangements

Abstract – The article deals with the properties of linear combinatorial optimization problems on a set of arrangements under probabilistic uncertainty. The statement of the problem, considering the possibility of stochastic uncertainty of the initial data, is considered. The properties of the formulated stochastic problems are explored

Linear-fractional combinatorial optimization problems: model and solving

Euclidean problems of linear-fractional combinatorial optimization on arrangements are discussed. Authors propose the model of practical problem. Also the polynomial algorithm for solving linear-fractional combinatorial optimization problems on arrangements is discussed

Линейные оптимизационные задачи на размещениях с вероятностной неопределенностью: свойства и решение

Досліджено властивості лінійних задач оптимізації на розміщеннях з імовірнісною невизначеністю, постановку яких здійснено на основі введення лінійного порядку на множині дискретних випадкових величин. Установлено властивості безумовної задачі, у якій коефіцієнти цільової функції або елементи мультимножини (але не те й те одночасно) є дискретними випадковими величинами. Ґрунтуючись на властивостях розв’язку безумовної задачі з детермінованими коефіцієнтами цільової функції, доведено властивості розв’язку для задачі, у якій коефіцієнти цільової функції є випадковими величинами. Запропоновано схему методу гілок і меж для розв’язання лінійних задач оптимізації на розміщеннях з імовірнісною невизначеністю, у якій також запропоновано правила галуження та відсікання множин.Authors study properties of linear optimization problems under probabilistic uncertainty while defining a problem based on the linear order on the set of discrete random variables. Properties of unconditional problem are established whose coefficients of the goal function or multiset’s elements (but not both simultaneously) are discrete random variables. Based on properties of the solution of an unconditional problem with deterministic coefficients, we prove solution’s properties for the problem with the goal function’s coefficients as discrete random variables. The scheme of the branch and bound method for solving the linear optimization problems on permutations under probabilistic uncertainty is proposed as well as rules of branching and truncation of sets.Исследуются свойства линейных задач оптимизации на размещениях с вероятностной неопределенностью, постановка которых осуществлена на основе введения линейного порядка на множестве дискретных случайных величин. Установлены свойства безусловной задачи, у которой коэффициенты целевой функции или элементы мультимножества (но не то и другое одновременно) являются дискретными случайными величинами. Основываясь на свойствах решения безусловной задачи с детерминированными коэффициентами целевой функции, доказаны свойства решения для задачи, в которой коэффициенты целевой функции являются случайными величинами. Предложена схема метода ветвей и границ для решения линейных задач оптимизации на размещениях с вероятностной неопределенностью, в которой также предложены правила ветвления и отсечения множеств

TRAP binding to the Bacillus subtilis trp leader region RNA causes efficient transcription termination at a weak intrinsic terminator

The Bacillus subtilis trpEDCFBA operon is regulated by a transcription attenuation mechanism controlled by the trp RNA-binding attenuation protein (TRAP). TRAP binds to 11 (G/U)AG repeats in the trp leader transcript and prevents formation of an antiterminator, which allows formation of an intrinsic terminator (attenuator). Previously, formation of the attenuator RNA structure was believed to be solely responsible for signaling RNA polymerase (RNAP) to halt transcription. However, base substitutions that prevent formation of the antiterminator, and thus allow the attenuator structure to form constitutively, do not result in efficient transcription termination. The observation that the attenuator requires the presence of TRAP bound to the nascent RNA to cause efficient transcription termination suggests TRAP has an additional role in causing termination at the attenuator. We show that the trp attenuator is a weak intrinsic terminator due to low GC content of the hairpin stem and interruptions in the U-stretch following the hairpin. We also provide evidence that termination at the trp attenuator requires forward translocation of RNA polymerase and that TRAP binding to the nascent transcript can induce this activity

In vivo tumor growth of high-grade serous ovarian cancer cell lines

OBJECTIVE: Genomic studies of ovarian cancer (OC) cell lines frequently used in research revealed that these cells do not fully represent high-grade serous ovarian cancer (HGSOC), the most common OC histologic type. However, OC lines that appear to genomically resemble HGSOC have not been extensively used and their growth characteristics in murine xenografts are essentially unknown. METHODS: To better understand growth patterns and characteristics of HGSOC cell lines in vivo, CAOV3, COV362, KURAMOCHI, NIH-OVCAR3, OVCAR4, OVCAR5, OVCAR8, OVSAHO, OVKATE, SNU119 and UWB1.289 cells were assessed for tumor formation in nude mice. Cells were injected intraperitoneally (i.p.) or subcutaneously (s.c.) in female athymic nude mice and allowed to grow (maximum of 90 days) and tumor formation was analyzed. All tumors were sectioned and assessed using H&E staining and immunohistochemistry for p53, PAX8 and WT1 expression. RESULTS: Six lines (OVCAR3, OVCAR4, OVCAR5, OVCAR8, CAOV3, and OVSAHO) formed i.p xenografts with HGSOC histology. OVKATE and COV362 formed s.c. tumors only. Rapid tumor formation was observed for OVCAR3, OVCAR5 and OVCAR8, but only OVCAR8 reliably formed ascites. Tumors derived from OVCAR3, OVCAR4, and OVKATE displayed papillary features. Of the 11 lines examined, three (Kuramochi, SNU119 and UWB1.289) were non-tumorigenic. CONCLUSIONS: Our findings help further define which HGSOC cell models reliably generate tumors and/or ascites, critical information for preclinical drug development, validating in vitro findings, imaging and prevention studies by the OC research community

Insights into anti-termination regulation of the hut operon in Bacillus subtilis: importance of the dual RNA-binding surfaces of HutP

The anti-termination protein, HutP, regulates the gene expression of the hut (histidine utilization) operon of Bacillus subtilis, by destabilizing the hut terminator RNA located upstream of the coding region encoding l-histidine degradation enzymes. On the basis of biochemical, in vivo and X-ray structural analyses, we now report that HutP uses its dual RNA-binding surfaces to access two XAG-rich regions (sites I and II) within the terminator RNA to mediate the destabilization process. In this process, HutP initiates destabilization at the 5′-end of its mRNA by binding to the first XAG-rich region (site I) and then accesses the second XAG-rich region (site II), located downstream of the stable G-C-rich segment of the terminator stem. By this action, HutP appears to disrupt the G-C-rich terminator stem, and thus prevents premature termination of transcription in the RNA segment preceding the regions encoding for the histidine degradation enzymes

Photo-induced antibacterial activity of four graphene based nanomaterials on a wide range of bacteria

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae