756 research outputs found
Molecular phylogeny based on its sequences of nrDNA of some species belonging to dodder (Cuscuta L.) genus from various ecological sites of Turkey
Nuclear ribosomal DNA (nrDNA) sequence data of the Cuscuta genus, which have been considered as one of the most popular sequences for phylogenetic inference in plants, have been studied from a phylogenetic perspective in agricultural and non-agricultural lands of Turkey. The samples of Cuscuta spp. were collected from different geographical regions of Turkey between the years of 2013-2015. Some other species, not available locally, were taken from the herbarium samples of some research units. In order to study the phylogenetic relations of collected species, DNA isolations were made from body tissue samples. Conserved regions on ribosomal DNA (rDNA) were amplified by universal primers via PCR method and cloned into a proper cloning vector. The cloned DNA fragments were sequenced and analysed by web-based and computer programs. DNA sequences of certain species were recorded to the National Center for Biotechnology Information (NCBI) database. Based on the morphological examination and molecular analyses of fresh and the herbarium specimen, 8 species were identified. The identified species were C. hyalina (Gene bank accession no. KY020420), C. monogyna (KY020421), C. europaea (KY020422), C. palaestina (KY020423), C. approximata (KY020424), C. kurdica (KY020427), C. kotschyana (KY020430) and C. babylonica (KY020431). The ITS (Internal Transcribed Spacer) region contains several indels in identified Cuscuta species with the length varying from 668 to 730 bp. Sequence divergence ranges from 1.00% to 8.00% within Cuscuta spp. Based on our findings, the ITS sequences provided phylogenetically informative results in combination with the secondary structures
Length-dependent translocation of polymers through nanochannels
We consider the flow-driven translocation of single polymer chains through
nanochannels. Using analytical calculations based on the de Gennes blob model
and mesoscopic numerical simulations, we estimate the threshold flux for the
translocation of chains of different number of monomers. The translocation of
the chains is controlled by the competition between entropic and hydrodynamic
effects, which set a critical penetration length for the chain before it can
translocate through the channel. We demonstrate that the polymers show two
different translocation regimes depending on how their length under confinement
compares to the critical penetration length. For polymer chains longer than the
threshold, the translocation process is insensitive to the number of monomers
in the chain as predicted in Sakaue {\it et al.}, {\it Euro. Phys. Lett.}, {\bf
72} 83 (2005). However, for chains shorter than the critical length we show
that the translocation process is strongly dependent on the length of the
chain. We discuss the possible relevance of our results to biological
transport.Comment: To appear in Soft Matter. 10 pages 9 Figure
Extended mixed integer quadratic programming for simultaneous distributed generation location and network reconfiguration
Introduction. To minimise power loss, maintain the voltage within the acceptable range, and improve power quality in power distribution networks, reconfiguration and optimal distributed generation placement are presented. Power flow analysis and advanced optimization techniques that can handle significant combinatorial problems must be used in distribution network reconfiguration investigations. The optimization approach to be used depends on the size of the distribution network. Our methodology simultaneously addresses two nonlinear discrete optimization problems to construct an intelligent algorithm to identify the best solution. The proposed work is novel in that it the Extended Mixed-Integer Quadratic Programming (EMIQP) technique, a deterministic approach for determining the topology that will effectively minimize power losses in the distribution system by strategically sizing and positioning Distributed Generation (DG) while taking network reconfiguration into account. Using an efficient Quadratic Mixed Integer Programming (QMIP) solver (IBM ®), the resulting optimization problem has a quadratic form. To ascertain the range and impact of various variables, our methodology outperforms cutting-edge algorithms described in the literature in terms of the obtained power loss reduction, according to extensive numerical validation carried out on typical IEEE 33- and 69-bus systems at three different load factors. Practical value. Examining the effectiveness of concurrent reconfiguration and DG allocation versus sole reconfiguration is done using test cases. According to the findings, network reconfiguration along with the installation of a distributed generator in the proper location, at the proper size, with the proper loss level, and with a higher profile, is effective.
Вступ. Для мінімізації втрат потужності, підтримки напруги в допустимому діапазоні та покращення якості електроенергії у розподільчих мережах представлена реконфігурація та оптимальне розміщення розподіленої генерації. При дослідженнях реконфігурації розподільної мережі необхідно використовувати аналіз потоку потужності та передові методи оптимізації, які можуть вирішувати серйозні комбінаторні проблеми. Підхід до оптимізації, що використовується, залежить від розміру розподільної мережі. Наша методологія одночасно вирішує дві задачі нелінійної дискретної оптимізації, щоби побудувати інтелектуальний алгоритм для визначення найкращого рішення. Пропонована робота є новою, оскільки вона використовує метод розширеного змішано-цілочисельного квадратичного програмування (EMIQP), детермінований підхід до визначення топології, що ефективно мінімізує втрати потужності в системі розподілу за рахунок стратегічного визначення розмірів та позиціонування розподіленої генерації (DG) з урахуванням реконфігурації мережі. При використанні ефективного солвера Quadratic Mixed Integer Programming (QMIP) (IBM®) результуюча задача оптимізації має квадратичну форму. Щоб з'ясувати діапазон та вплив різних змінних, наша методологія перевершує передові алгоритми, описані в літературі, з точки зору одержаного зниження втрат потужності, згідно з великою числовою перевіркою, проведеною на типових системах з шинами IEEE 33 і 69 при трьох різних коефіцієнтах навантаження. Практична цінність. Вивчення ефективності одночасної реконфігурації та розподілу DG у порівнянні з єдиною реконфігурацією проводиться з використанням тестових прикладів. Відповідно до результатів, реконфігурація мережі разом із установкою розподіленого генератора в потрібному місці, належного розміру, з належним рівнем втрат і з більш високим профілем є ефективною
PHYTOCHEMICAL STUDY AND THE ANTIPROLIFERATIVE ACTIVITY OF INULA VULGARIS SPECIES GROWN IN LEBANON
Objective: Cancer represents the second leading cause of death after stroke and heart diseases. Plant extracts have long been used in traditional medicine for the prevention and treatment of many illnesses, including some types of cancer. The aim of this study was to evaluate the antiproliferative effects of ethyl acetate fractions of two Lebanese herbs: Inula viscosa (I. vis) and Inula vulgaris (I. vul).Methods: Plants were extracted with ethanol followed by ethyl acetate, then dried and tested on three cell lines including CaCO2, HepG2, and MCF7, to check for their viability and antiproliferative activity, using trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Proton (1H) and carbon (13C) nuclear magnetic resonance spectrometry (NMR) were used to identify the compounds that have been isolated from both Inula species.Results: The current findings were consistent for both trypan blue and MTT assays. The results showed that the most potent effect for I. vul was HepG2 (IC50 20 µg/ml, 27 µg/ml), and for I. vis on MCF7 (9 µg/ml, 15 µg/ml) and CaCO2 (12 µg/ml, 22 µg/ml) in the two mentioned assays respectively. However, insignificant differences were observed among the studied plants for each of the evaluated cells indicating comparable potencies. Quercetin, quercetin glycoside, and epicatechin derivatives were isolated by fractionation on column chromatography and identified using NMR spectroscopy.Conclusion: The antiproliferative activities of the two plants could be related to their content that is significant for high levels of secondary metabolites. The identification of those compounds is necessary to establish a relationship between their chemical structures and their activities
Studies on Parameters Influencing the Performance of Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) in Detecting Prunus Necrotic Ringpot Virus (PNRSV)
In order to have a more detailed understanding of the various factors influencing a reverse transcriptase
polymerase chain reaction (RT-PCR), a number of important parameters such as Mg+2, primer, enzyme concentration
and others were optimized for the detection of Prunus necrotic ringspot virus (PNRSV). Using a PNRSV isolate with
a pair of primers, complementary DNA of viral genome as template, and an appropriate enzyme together with magnesium
chloride, the following optimal conditions were identified: primer concentration between 0.2 and 0.0002 pmol
µl-1 and 0.06–2 units µl-1 for Taq DNA polymerase enzyme for a 50 µl reaction volume when other parameters were
optimum; magnesium chloride concentration less than 2.5 mM; dNTP concentration between 1 and 10 mM. The
optimum cDNA amount should be ~360 ng for a 50 µl reaction mixture. When these optimized concentrations and/or
values of the main PCR parameters were brought together for a new RT-PCR, a clear and a reliable PNRSV detection
having no background was performed from both growth-chamber and field-grown PNRSV-infected plants
Characterization of a ballistic supermirror neutron guide
We describe the beam characteristics of the first ballistic supermirror
neutron guide H113 that feeds the neutron user facility for particle physics
PF1B of the Institute Laue-Langevin, Grenoble (ILL). At present, the neutron
capture flux density of H113 at its 20x6cm2 exit window is 1.35x10^10/cm^2/s,
and will soon be raised to above 2x10^10/cm^2/s. Beam divergence is no larger
than beam divergence from a conventional Ni coated guide. A model is developed
that permits rapid calculation of beam profiles and absolute event rates from
such a beam. We propose a procedure that permits inter-comparability of the
main features of beams emitted from ballistic or conventional neutron guides.Comment: 15 pages, 11 figures, to be submitted to Nuclear Instruments and
Methods
TOPRAKLARDA BOR ADSORPSİYONU
Bu araştırma farklı özelliklere sahip topraklar ın bor adsorpsiyon izotermlerini incelemek üzere yürütülmüştür. Langmuir ve Freundlich adsorpsiyon izotermi modellerine göre değerlendirilen B adsorpsiyonunda, Langmuir modelinin düşük B konsantrasyonlan için geçerli oldu ğu, Freundlich modelinin ise hem düşük, hem de yüksek konsantrasyonlarda geçerli oldu ğu saptanmıştır. Langmuir b ve Freundlich k sabitleri ile kil kapsam ı ve kalyon değişim kapasitesi aras ında sırasıyla; % 1 ve % 5 düzeyinde önemli bir ili şki bulunmuştur. Langmuir K sabiti ile organik madde aras ında % 1 düzeyinde önemli bir ilişki tespit edilmiştir. Langmuir b ve Freundlich k de ğerleri ile pH arasında % 1, Langmuir K değeri ile ise % 5 düzeyinde negatif bir ilişki olduğu belirlenmiştir
Coaxial Jets with Disparate Viscosity: Mixing and Laminarization Characteristics
Mixing of fluids in a coaxial jet is studied under four distinct viscosity ratios, m = 1, 10, 20 and 40, using highly resolved large-eddy simulations (LES), particle image velocimetry and planar laser-induced fluorescence. The accuracy of predictions is tested against data obtained by the simultaneous experimental measurements of velocity and concentration fields. For the highest and lowest viscosity ratios, standard RANS models with unclosed terms pertaining to viscosity variations are employed. We show that the standard Reynolds-averaged Navier-Stokes (RANS) approach with no explicit modelling for variable-viscosity terms is not applicable whereas dynamic LES models provide high-quality agreement with the measurements. To identify the underlying mixing physics and sources of discrepancy in RANS predictions, two distinct mixing modes are defined based on the viscosity ratio. Then, for each mode, the evolution of mixing structures, momentum budget analysis with emphasis on variable-viscosity terms, analysis of the turbulent activity and decay of turbulence are investigated using highly resolved LES data. The mixing dynamics is found to be quite distinct in each mixing mode. Variable viscosity manifests multiple effects that are working against each other. Viscosity gradients induce additional instabilities while increasing overall viscosity decreases the effective Reynolds number leading to laminarization of the turbulent jet, explaining the lack of dispersion and turbulent diffusion. Momentum budget analysis reveals that variable-viscosity terms are significant to be neglected. The scaling of the energy spectrum cascade suggests that in the TLL mode the unsteady laminar shedding is responsible for the eddies observed
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