10,329 research outputs found
Temporal and Spatial Expression Patterns of miR-302 and miR-367 During Early Embryonic Chick Development
published_or_final_versio
Inorganic-ligand exchanging time effect in PbS quantum dot solar cell
We investigate time-dependent inorganic ligand exchanging effect and photovoltaic performance of lead sulfide (PbS) nanocrystal films. With optimal processing time, volume shrinkage induced by residual oleic acid of the PbS colloidal quantum dot (CQD) was minimized and a crack-free film was obtained with improved flatness. Furthermore, sufficient surface passivation significantly increased the packing density by replacing from long oleic acid to a short iodide molecule. It thus facilities exciton dissociation via enhanced charge carrier transport in PbS CQD films, resulting in the improved power conversion efficiency from 3.39% to 6.62%. We also found that excess iodine ions on the PbS surface rather hinder high photovoltaic performance of the CQD solar cell
Crystal Structure of the Rad3/XPD regulatory domain of Ssl1/p44
The Ssl1/p44 subunit is a core component of the yeast/mammalian general transcription factor TFIIH, which is involved in transcription and DNA repair. Ssl1/p44 binds to and stimulates the Rad3/XPD helicase activity of TFIIH. To understand the helicase stimulatory mechanism of Ssl1/p44, we determined the crystal structure of the N-terminal regulatory domain of Ssl1 from Saccharomyces cerevisiae. Ssl1 forms a von Willebrand factor A fold in which a central six-stranded beta-sheet is sandwiched between three alpha helices on both sides. Structural and biochemical analyses of Ssl1/p44 revealed that the beta 4-alpha 5 loop, which is frequently found at the interface between von Willebrand factor A family proteins and cellular counterparts, is critical for the stimulation of Rad3/XPD. Yeast genetics analyses showed that double mutation of Leu-239 and Ser-240 in the beta 4-alpha 5 loop of Ssl1 leads to lethality of a yeast strain, demonstrating the importance of the Rad3-Ssl1 interactions to cell viability. Here, we provide a structural model for the Rad3/XPD-Ssl1/p44 complex and insights into how the binding of Ssl1/p44 contributes to the helicase activity of Rad3/XPD and cell viability.X1165Ysciescopu
SCORE and SCORE2 in East Asian Population: A Performance Comparison
BACKGROUND: Systematic COronary Risk Evaluation 2 (SCORE2) and SCORE2-Older Persons (OP) models have been proposed as new cardiovascular risk evaluation tools. OBJECTIVES: Systematic COronary Risk Evaluation 2 (SCORE2) and SCORE2-Older Persons (OP) models have been proposed as new cardiovascular risk evaluation tools. METHODS: A total of 324,384 NHIS examinees from 2004 to 2005 were divided into 5 age groups: 40-49 years, 50-59 years, 60-69 years,70-79 years, and more than 80 years. The examinees had their predicted cardiovascular disease risks calculated by using SCORE, SCORE2, SCORE-OP, and SCORE2-OP models. The low-risk model was applied on the basis of the cohort’s observed event rates. The observed and predicted cardiovascular risks were compared. RESULTS: A total of 324,384 subjects were included (mean age 51.4 ± 7.3 years; women, 37.9% for the SCORE/SCORE2 group and mean age 73.0 ± 2.8 years; women, 47.5% for the SCORE/SCORE2-OP group). Over a median follow-up of 9 years, cardiovascular events occurred in 15.0% and 28.9% in SCORE/SCORE2 and SCORE/SCORE2-OP groups, respectively. The SCORE/SCORE-OP model underestimated cardiovascular disease risk in young men (aged 40-49 years) and women (aged 40-59 years) and overestimated it in older age groups. In contrast, SCORE2/SCORE2-OP invariably overestimated the risk in all age groups and sexes. SCORE2/SCORE2-OP showed no improvement in Harrell’s concordance index (C-index) compared with SCORE/SCORE-OP. Calibration plots favored SCORE2 over SCORE but not SCORE2-OP over SCORE-OP. CONCLUSIONS: Both SCORE2/SCORE2-OP and SCORE/SCORE-OP overestimated cardiovascular disease risk with low performance. SCORE2/SCORE2-OP showed slight improvement over older versions, but modifications are necessary for the East Asian population
Optimal design of multi-channel microreactor for uniform residence time distribution
Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow
Spin Discrimination in Three-Body Decays
The identification of the correct model for physics beyond the Standard Model
requires the determination of the spin of new particles. We investigate to
which extent the spin of a new particle can be identified in scenarios
where it decays dominantly in three-body decays . Here we
assume that is a candidate for dark matter and escapes direct detection at
a high energy collider such as the LHC. We show that in the case that all
intermediate particles are heavy, one can get information on the spins of
and at the LHC by exploiting the invariant mass distribution of the two
standard model fermions. We develop a model-independent strategy to determine
the spins without prior knowledge of the unknown couplings and test it in a
series of Monte Carlo studies.Comment: 31+1 pages, 4 figures, 8 tables, JHEP.cls include
High-yield isolation of extracellular vesicles using aqueous two-phase system
Extracellular vesicles (EVs) such as exosomes and microvesicles released from cells are potential biomarkers for blood-based diagnostic applications. To exploit EVs as diagnostic biomarkers, an effective pre-analytical process is necessary. However, recent studies performed with blood-borne EVs have been hindered by the lack of effective purification strategies. In this study, an efficient EV isolation method was developed by using polyethylene glycol/dextran aqueous two phase system (ATPS). This method provides high EV recovery efficiency (similar to 70%) in a short time (similar to 15 min). Consequently, it can significantly increase the diagnostic applicability of EVs.113219Ysciescopu
The Escherichia coli transcriptome mostly consists of independently regulated modules
Underlying cellular responses is a transcriptional regulatory network (TRN) that modulates gene expression. A useful description of the TRN would decompose the transcriptome into targeted effects of individual transcriptional regulators. Here, we apply unsupervised machine learning to a diverse compendium of over 250 high-quality Escherichia coli RNA-seq datasets to identify 92 statistically independent signals that modulate the expression of specific gene sets. We show that 61 of these transcriptomic signals represent the effects of currently characterized transcriptional regulators. Condition-specific activation of signals is validated by exposure of E. coli to new environmental conditions. The resulting decomposition of the transcriptome provides: a mechanistic, systems-level, network-based explanation of responses to environmental and genetic perturbations; a guide to gene and regulator function discovery; and a basis for characterizing transcriptomic differences in multiple strains. Taken together, our results show that signal summation describes the composition of a model prokaryotic transcriptome
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