Measurements of Extended Magnetic Fields in Laser-Solid Interaction

Magnetic fields generated from a laser-foil interaction are measured with high fidelity using a proton radiography scheme with in situ x-ray fiducials. In contrast to prior findings under similar experimental conditions, this technique reveals the self-generated, Biermann-battery fields extend beyond the edge of the expanding plasma plume to a radius of over 3.5 mm by t=+1.4 ns, a result not captured in state-of-the-art magneto-hydrodynamics simulations. An analysis of two mono-energetic proton populations confirms that proton deflection is dominated by magnetic fields far from the interaction (>2 mm) and electric fields are insignificant. Comparisons to prior work suggest a new physics mechanism for the magnetic field generation and transport in laser-solid interactions.Comment: 9 pages, 8 figure

CLINICALLY RELEVANT MINOR HISTOCOMPATIBILITY ANTIGENS FOR RUSSIAN PATIENTS UNDERGOING HEMATOPOIETIC STEM CELL TRANSPLANTATION

Hematopoietic stem cell transplantation (HSCT) from healthy donors is used for blood cancer treatment. Alloreactive graft-versus-host disease (GvHD) is one of the post-transplant detrimental side effects, and the main reason for GVHD after HSCT fully matched for human leukocyte peptide antigens (HLA) presented by HLA molecules on cell surface. These polymorphic peptides, minor histocompatibility antigens (MiHA), arise from any genes, including those expressed at hematopoietic tissues. The latter may lead to the s.c. graft-versus-leukemia effect (GvL), thus preventing relapse of a malignancy. A*02:01 is one of the most frequent HLA alleles for European part of Russia. We assessed frequencies for 20 MiHA-encoded genetic polymorphisms, presented via A*02:01 allele, for plausible bone marrow donors, or hematopoietic stem cells (HSC) from the Donor Registry at Russian National Research Center for Hematology, we have also determined a number of immunogenic mismatches for these 20 MiHA in real donor – recipient pairs. A total of 608 potential donors, 90 donors and 92 recipients were genotyped. Using public data, we have shown that frequencies for MiHA coding genes are most close to appropriate frequencies among the European population. We have calculated probability of MiHA-specific alloimmune response after HSCT: there are chances of 33 and 75% for three or more immunogenic mismatches (IM) for related and unrelated HSCTs, respectively. Real frequencies for immune mismatch in 20 related and 20 unrelated donor – recipient pairs are in accordance with estimated theoretical probabilities. As based on the calculated frequencies, we suggest the LB-NDC80- 1P/A, LB-CCL4- 1T, and HA-1 MiHA to be the most promising minor antigens for targeted cell therapies of hematopoietic tissue malignancies. The data obtained could be used for planning allo-HSCTs in Russian patients

Расчетное исследование выхода твердых продуктов пиролиза древесины при повышенном давлении

The kinetic model of wood pyrolysis under pressure is discussed in the present paper taking into account the diffusion of the resulting gas-phase products (i.e. heavy hydrocarbons) and their decomposition reactions. This model is based on a simplified mechanism of wood pyrolysis, including two parallel chemical reactions, viz. the primary decomposition reaction of  wood biomass with the formation of solid and gaseous components and the thermal decomposition reaction in the biomass pores of hydrocarbons formed in the primary process. The model takes into account the diffusion processes of the primary pyrolysis products from the resulting pores and thermal decomposition in the pores of these products. Based on the developed model, a computer program for calculating the main parameters of the pyrolysis process under pressure was created and the mass yield of solid pyrolysis products under various conditions was calculated. The calculation took into account the main parameters that affect the yield of solid wood biomass products, viz. temperature and pyrolysis pressure, particle sizes, porosity, etc. The calculations demonstrated that the increase of the pressure at which the pyrolysis of wood biomass is carried out causes an increase of the formation of the amount of solid products, which corresponds to the available experimental data. It was established that at a pressure of 1 atm when a sample size is of 0.025 m, the maximum yield of solid products is observed at the temperature of 600 °C. As the pressure increases the maximum yield increases, while the temperature at which the maximum is reached decreases. So, at a pressure of 10 atm when a particle size is of 0.025 m, the maximum yield of solid products is observed at the temperature of about 500 °C, and it is higher than that at 1 atm by 1.18 times. It was also determined that the temperature of the maximum yield of charcoal decreases with increasing sizes of pyrolyzable samples. Thus, when a sample size is of 0.5 m, this temperature is about 400 °C at 10 atm.. В статье представлена кинетическая модель пиролиза древесины под давлением с учетом диффузии образующихся газофазных продуктов (тяжелых углеводородов) и реакций их разложения. В основу модели положен упрощенный механизм пиролиза древесины, включающий две последовательные химические реакции: первичную реакцию разложения древесной биомассы с образованием твердых и газообразных компонентов и реакцию термического разложения в порах биомассы углеводородов, образовавшихся в первичном процессе. Модель учитывает диффузию первичных продуктов пиролиза из образовавшихся пор и термическое разложение их в порах. На основании разработанной модели создана компьютерная программа расчета основных параметров процесса пиролиза под давлением, проведены вычисления массового выхода твердых продуктов пиролиза в различных условиях. При расчете учитывались основные параметры, влияющие на выход твердых продуктов древесной биомассы: температура и давление пиролиза, размеры частиц, пористость и др. Установлено, что повышение давления, при котором осуществляется пиролиз древесной биомассы, приводит к увеличению образования количества твердых продуктов, что соответствовало экспериментальным данным. При давлении 1 атм и размере частицы 0,025 м максимальный выход твердых продуктов наблюдается при температуре 600 °С. С ростом давления значение максимального выхода возрастает, при этом температура, при которой достигается максимум, снижается. При давлении 10 атм и размере частицы 0,025 м максимальный выход твердых продуктов наблюдается при температуре около 500 °С – в 1,18 раза больше, чем при 1 атм. Отмечено, что температура максимального выхода древесного угля снижается с увеличением размеров пиролизуемых частиц. Так, при размере частицы 0,5 м эта температура составляет порядка 400 °С при 10 атм

Применимость соединений на основе никеля в качестве катализаторов термоконверсии первичных продуктов пиролиза биомассы

The paper discusses the results of an experimental study of the thermal decomposition of pyrolytic tar carried out in isothermal conditions at temperatures of 300, 350 and 400 °C. It was found that the kinetics of this process can be described using the Avrami–Erofeev equation with a variable parameter n. Analysis of the established data showed that the area of variation of this index included values from 0.415 to 1.238. The mean value of the n parameter calculated for all variants of the study was 0.694 (95 % CI from 0.605 to 0.783), and the median value was 0.639. As is known, the Avrami–Erofeev equation describes the kinetics of thermal decomposition of matter in the condensed state, determined by the nucleation process. This suggests that in the case of thermal decomposition of pyrolytic tar in the temperature range 300–400 °С this process is the limiting stage of the total process. The pyrolytic tarn decomposition rate was found to increase in the case of introduction of particles of nickel catalyst developed at the Physical and Technical Institute of the National Academy of Sciences of Belarus into the reaction zone. However, only with respect to one sample, it can be confidently stated that this is the result of the catalytic effect of applied nickel catalyst. Based on the established data, it was concluded that it is promising to use a nickel-containing catalyst in the processes of thermal decomposition of heavy hydrocarbons formed in the processes of thermochemical conversion of biomass.Обсуждаются результаты экспериментального исследования термического разложения пиролитической смолы, выполненного в изотермических условиях при температурах 300, 350 и 400 °С с использованием никельсодержащих катализаторов системы Ni–Fe–Mo. Показано, что кинетику этого процесса можно описать с помощью уравнения Аврами–Ерофеева с переменным показателем n, при этом область изменения этого показателя составляет от 0,415 до 1,238. Среднее значение показателя n, рассчитанное по всем вариантам исследования, равно 0,694 (95 % ДИ от 0,605 до 0,783), а медианное значение – 0,639. Как известно, уравнение Аврами–Ерофеева описывает кинетику термического разложения вещества в конденсированном состоянии, которая определяется процессом зародышеобразования. Высказано предположение, что в случае термического разложения пиролитической смолы в интервале температур 300–400 °С данный процесс является лимитирующей стадией суммарного процесса. Обнаружено, что скорость разложения пиролитической смолы возрастает в случае внесения в реакционную зону частиц никельсодержащего катализатора, разработанного специалистами Физико-технического института Национальной академии наук Беларуси. На основании установленных данных сделан вывод о перспективности использования никельсодержащего катализатора в процессах термического разложения тяжелых углеводородов, образующихся в процессах термохимической конверсии биомассы

Effect of pathology type and severity on the distribution of MRI signal intensities within the degenerated nucleus pulposus: application to idiopathic scoliosis and spondylolisthesis

<p>Abstract</p> <p>Background</p> <p>Disc degeneration is characterized by a loss of cellularity, degradation of the extracellular matrix, and, as a result, morphological changes and biomechanical alterations. We hypothesized that the distribution of the MR signal intensity within the nucleus zone of the intervertebral disc was modified according to the pathology and the severity of the pathology. The objective of this study was to propose new parameters characterizing the distribution of the signal intensity within the nucleus zone of lumbar intervertebral discs, and to quantify these changes in patients suffering from spondylolisthesis or idiopathic scoliosis.</p> <p>Methods</p> <p>A retrospective study had been performed on T2-weighted MR images of twenty nine patients suffering from spondylolisthesis and/or scoliosis. The high intensity zone of the nucleus pulposus was semi-automatically detected. The distance "DX" between the center weighted by the signal intensity and the geometrical center was quantified. The sum of the signal intensity on the axis perpendicular to the longitudinal axis of the disc was plotted for each position of the longitudinal axis allowing defining the maximum sum "SM" and its position "PSM".</p> <p>Results</p> <p>"SM" was clearly higher and "PSM" was more shifted for scoliosis than for spondylolisthesis. A two-way analysis of variance showed that the differences observed on "DX" were not attributed to the pathology nor its severity, the differences observed on "SM" were attributed to the pathology but not to its severity, and the differences observed on "PSM" were attributed to both the pathology and its severity.</p> <p>Conclusions</p> <p>The technique proposed in this study showed significant differences in the distribution of the MR signal intensity within the nucleus zone of intervertebral discs due to the pathology and its severity. The dependence of the "PSM" parameter to the severity of the pathology suggests this parameter as a predictive factor of the pathology progression. This new technique should be useful for the early diagnosis of intervertebral disc pathologies as it highlights abnormal patterns in the MRI signal for low severity of the pathology.</p

Continuous-wave biexciton lasing at room temperature using solution-processed quantum wells

Solution-processed inorganic and organic materials have been pursued for more than a decade as low-threshold, high-gain lasing media, motivated in large part by their tunable optoelectronic properties and ease of synthesis and processing. Although both have demonstrated stimulated emission and lasing, they have not yet approached the continuous-wave pumping regime. Two-dimensional CdSe colloidal nanosheets combine the advantage of solution synthesis with the optoelectronic properties of epitaxial two-dimensional quantum wells. Here, we show that these colloidal quantum wells possess large exciton and biexciton binding energies of 132 meV and 30 meV, respectively, giving rise to stimulated emission from biexcitons at room temperature. Under femtosecond pulsed excitation, close-packed thin films yield an ultralow stimulated emission threshold of 6 μJ cm(-2), sufficient to achieve continuous-wave pumped stimulated emission, and lasing when these layers are embedded in surface-emitting microcavities

A General Definition and Nomenclature for Alternative Splicing Events

Understanding the molecular mechanisms responsible for the regulation of the transcriptome present in eukaryotic cells is one of the most challenging tasks in the postgenomic era. In this regard, alternative splicing (AS) is a key phenomenon contributing to the production of different mature transcripts from the same primary RNA sequence. As a plethora of different transcript forms is available in databases, a first step to uncover the biology that drives AS is to identify the different types of reflected splicing variation. In this work, we present a general definition of the AS event along with a notation system that involves the relative positions of the splice sites. This nomenclature univocally and dynamically assigns a specific “AS code” to every possible pattern of splicing variation. On the basis of this definition and the corresponding codes, we have developed a computational tool (AStalavista) that automatically characterizes the complete landscape of AS events in a given transcript annotation of a genome, thus providing a platform to investigate the transcriptome diversity across genes, chromosomes, and species. Our analysis reveals that a substantial part—in human more than a quarter—of the observed splicing variations are ignored in common classification pipelines. We have used AStalavista to investigate and to compare the AS landscape of different reference annotation sets in human and in other metazoan species and found that proportions of AS events change substantially depending on the annotation protocol, species-specific attributes, and coding constraints acting on the transcripts. The AStalavista system therefore provides a general framework to conduct specific studies investigating the occurrence, impact, and regulation of AS

Charged excitons in modulation-doped quantum wires

We report on the observation of negatively- and positively-charged excitons in the photoluminescence spectra of V-groove quantum wires. The. charged exciton binding energy increases with the strength of the quantum confinement. We demonstrate that fluctuations of the confinement potential cause the localization of the exciton and of the charged exitons on the same location. We discover that a large fraction of the enhancement of the charged exciton "binding energies" has a kinetic origin associated with the recoil energy transferred to the remaining carrier during the emission process

Table_1_Comparative Genomic Analysis of Holospora spp., Intranuclear Symbionts of Paramecia.xlsx

<p>While most endosymbiotic bacteria are transmitted only vertically, Holospora spp., an alphaproteobacterium from the Rickettsiales order, can desert its host and invade a new one. All bacteria from the genus Holospora are intranuclear symbionts of ciliates Paramecium spp. with strict species and nuclear specificity. Comparative metabolic reconstruction based on the newly sequenced genome of Holospora curviuscula, a macronuclear symbiont of Paramecium bursaria, and known genomes of other Holospora species shows that even though all Holospora spp. can persist outside the host, they cannot synthesize most of the essential small molecules, such as amino acids, and lack some central energy metabolic pathways, including glycolysis and the citric acid cycle. As the main energy source, Holospora spp. likely rely on nucleotides pirated from the host. Holospora-specific genes absent from other Rickettsiales are possibly involved in the lifestyle switch from the infectious to the reproductive form and in cell invasion.</p