1,601 research outputs found

    Multi-GeV wakefield acceleration in a plasma-modulated plasma accelerator

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    We investigate the accelerator stage of a plasma-modulated plasma accelerator (P-MoPA) [Jakobsson et al., Phys. Rev. Lett. 127, 184801 (2021)] using both the paraxial wave equation and particle-in-cell (PIC) simulations. We show that adjusting the laser and plasma parameters of the modulator stage of a P-MoPA allows the temporal profile of pulses within the pulse train to be controlled, which in turn allows the wake amplitude in the accelerator stage to be as much as 72% larger than that generated by a plasma beat-wave accelerator with the same total drive laser energy. Our analysis shows that Rosenbluth-Liu detuning is unimportant in a P-MoPA if the number of pulses in the train is less than ∼30, and that this detuning is also partially counteracted by increased red-shifting, and hence increased pulse spacing, towards the back of the train. An analysis of transverse mode oscillations of the driving pulse train is found to be in good agreement with 2D (Cartesian) PIC simulations. PIC simulations demonstrating energy gains of ∼1.5GeV (∼2.5GeV) for drive pulse energies of 2.4J (5.0J) are presented. Our results suggest that P-MoPAs driven by few-joule, picosecond pulses, such as those provided by high-repetition-rate thin-disk lasers, could accelerate electron bunches to multi-GeV energies at pulse repetition rates in the kilohertz range

    Negative regulation of urokinase receptor activity by a GPI-specific phospholipase C in breast cancer cells.

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    The urokinase receptor (uPAR) is a glycosylphosphatidylinositol (GPI)-anchored protein that promotes tissue remodeling, tumor cell adhesion, migration and invasion. uPAR mediates degradation of the extracellular matrix through protease recruitment and enhances cell adhesion, migration and signaling through vitronectin binding and interactions with integrins. Full-length uPAR is released from the cell surface, but the mechanism and significance of uPAR shedding remain obscure. Here we identify transmembrane glycerophosphodiesterase GDE3 as a GPI-specific phospholipase C that cleaves and releases uPAR with consequent loss of function, whereas its homologue GDE2 fails to attack uPAR. GDE3 overexpression depletes uPAR from distinct basolateral membrane domains in breast cancer cells, resulting in a less transformed phenotype, it slows tumor growth in a xenograft model and correlates with prolonged survival in patients. Our results establish GDE3 as a negative regulator of the uPAR signaling network and, furthermore, highlight GPI-anchor hydrolysis as a cell-intrinsic mechanism to alter cell behavior

    “Зізнання авантюриста Фелікса Крулля” Томаса Манна як пародія на велику автобіографію

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    Статтю присвячено розгляду рецепції та відображення “Поезії і правди” Й.-В. Гете в романі Т. Манна “Зізнання авантюриста Фелікса Крулля”. Представлена розвідка продовжує ряд наукових досліджень, присвячених вивченню особливостей рецепції автобіографії Й.-В. Гете, зокрема в німецькомовному літературному просторі. При дослідженні особливостей наявного в аналізованому нами романі пародійного наслідування Й.-В. Гете основна увага зосереджується автором на його стилістичному та тематичному рівнях.Статья посвящена рассмотрению рецепции и отражения “Поэзии и правды” Й.-В. Гете в романе Т. Манна “Признания авантюриста Феликса Крулля”. Представленная статья продолжает ряд научных исследований, посвященных изучению особенностей рецепции автобиографии Й.-В. Гете в частности в немецкоязычном литературном пространстве. При изучении особенностей имеющихся в анализированном нами романе пародийного подражания Й.-В. Гете основное внимание автор сосредотачивает на его стилистическом и тематическом уровнях.The article focuses on the reception of Goethe’s “Poetry and Truth” and its reflection in T. Mann’s novel “The Confession of adventurer Felix Crool”. The given article extends the series of scientific investigations that deal with the peculiarities of Goethe’s reception in German literature. Studying the parody imitation peculiarities of Goethe in the analysed novel, the main attention is paid to the stylistic and theme levels

    Efficient Double Fragmentation ChIP-seq Provides Nucleotide Resolution Protein-DNA Binding Profiles

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    Immunoprecipitated crosslinked protein-DNA fragments typically range in size from several hundred to several thousand base pairs, with a significant part of chromatin being much longer than the optimal length for next-generation sequencing (NGS) procedures. Because these larger fragments may be non-random and represent relevant biology that may otherwise be missed, but also because they represent a significant fraction of the immunoprecipitated material, we designed a double-fragmentation ChIP-seq procedure. After conventional crosslinking and immunoprecipitation, chromatin is de-crosslinked and sheared a second time to concentrate fragments in the optimal size range for NGS. Besides the benefits of increased chromatin yields, the procedure also eliminates a laborious size-selection step. We show that the double-fragmentation ChIP-seq approach allows for the generation of biologically relevant genome-wide protein-DNA binding profiles from sub-nanogram amounts of TCF7L2/TCF4, TBP and H3K4me3 immunoprecipitated material. Although optimized for the AB/SOLiD platform, the same approach may be applied to other platforms

    Gauss Law Constraints in Chern-Simons Theory From BRST Quantization

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    The physical state condition in the BRST quantization of Chern-Simons field theory is used to derive Gauss law constraints in the presence of Wilson loops, which play an important role in explicitly establishing the connection of Chern-Simons field theory with 2-dimensional conformal field theory.Comment: Some typetwritten errors have been corrected. A few formulas have been modified to make the arguments clear. A little English have been re-edite

    Impact of Extraction Time during Donation after Circulatory Death Organ Procurement on Kidney Function after Transplantation in the Netherlands

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    Background:In The Netherlands, 60% of deceased-donor kidney offers are after donation after circulatory death. Cold and warm ischemia times are known risk factors for delayed graft function (DGF) and inferior allograft survival. Extraction time is a relatively new ischemia time. During procurement, cooling of the kidneys is suboptimal with ongoing ischemia. However, evidence is lacking on whether extraction time has an impact on DGF if all ischemic periods are included.Methods:Between 2012 and 2018, 1524 donation after circulatory death kidneys were procured and transplanted in The Netherlands. Donation and transplantation-related data were obtained from the database of the Dutch Transplant Foundation. The primary outcome parameter was the incidence of DGF. Results:In our cohort, extraction time ranged from 14 to 237 min, with a mean of 62 min (SD 32). In multivariate logistic regression analysis, extraction time was an independent risk factor for incidence of DGF (odds ratio per minute increase 1.008; 95% confidence interval, 1.003-1.013; P = 0.001). The agonal phase, hypoperfusion time, and anastomosis time were not independent risk factors for incidence of DGF. Conclusions:Considering all known ischemic periods during the donation after the circulatory death process, prolonged kidney extraction time increased the risk of DGF after kidney transplantation.</p
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