322 research outputs found
Octet Quark Contents from SU(3) Flavor Symmetry
With the parametrization of parton distribution functions (PDFs) of the
proton by Soffer \textit{et al.}, we extend the valence quark contents to other
octet baryons by utilizing SU(3) flavor symmetry. We find the method
practically useful. Fragmentation functions (FFs) are further obtained through
the phenomenological Gribov-Lipatov relation at the region. Our
results are compared with different models, and these different predictions can
be discriminated by upcoming experiments.Comment: 6 pages, 5 figures, final version for journal publicatio
Electrolyzer Design for Flexible Decoupled Water Splitting and Organic Upgrading with Electron Reservoirs
The Bigger Picture Electrocatalytic water splitting is a green approach to producing clean H2 fuel, especially when it is driven by renewable energy sources. Conventional water electrolysis always produces H2 and O2 simultaneously under corrosive acidic or alkaline conditions with large voltage inputs, posing safety concerns of H2/O2 mixing. Therefore, it is desirable to develop a new electrolyzer design for decoupled water splitting in an eco-friendly neutral solution with small voltage inputs to enable separated H2 and O2 evolution. Herein, we report (ferrocenylmethyl)trimethylammonium chloride and Na4[Fe(CN)6] as proton-independent electron reservoirs for achieving separated H2 and O2 evolution in near-neutral solution driven by electricity or solar cells under sunlight irradiation. Na4[Fe(CN)6] can also integrate H2 evolution with organic oxidation to yield H2 and high-value organic products. This work offers promising economic and safety advantages for sustainable H2 production and organic transformation
Species richness, functional traits and climate interactively affect tree survival in a large forest biodiversity experiment
1. Tree survival affects forest biodiversity, structure and functioning. However, little is known about feedback effects of biodiversity on survival and its dependence on functional traits and interannual climatic variability.
2. With an individual-based dataset from a large subtropical forest biodiversity experiment, we evaluated how species richness, functional traits and time-dependent covariates affected annual tree survival rates from age 3β12 (years) after planting 39 species across a diversity gradient from 1 to 2, 4, 8 and 16 tree species.
3. We found that overall survival rates marginally increased with diversity at the plot level, with large variation among plots within diversity levels. Significant variation among species in survival responses to diversity and changes in
these responses with age were related to species functional traits and climatic conditions. Generally, survival rates of conservative species (evergreen, late-successional species with thick leaves and high carbon to nitrogen ratio but low
specific leaf area, leaf phosphorus and hydraulic conductivity) increased with diversity, age and yearly precipitation, whereas acquisitive species showed opposite responses.
4. Synthesis. Our results indicate that interactions between diversity, species functional traits and yearly climatic conditions can balance survival among species in diverse forests. Planting mixtures of species that differ in functional traits in afforestation projects may lead to a positive feedback loop where biodiversit
PP1A-Mediated Dephosphorylation Positively Regulates YAP2 Activity
Background: The Hippo/MST1 signaling pathway plays an important role in the regulation of cell proliferation and apoptosis. As a major downstream target of the Hippo/MST1 pathway, YAP2 (Yes-associated protein 2) functions as a transcriptional cofactor that has been implicated in many biological processes, including organ size control and cancer development. MST1/Lats kinase inhibits YAP2βs nuclear accumulation and transcriptional activity through inducing the phosphorylation at serine 127 and the sequential association with 14-3-3 proteins. However, the dephosphorylation of YAP2 is not fully appreciated. Methodology/Principal Findings: In the present study, we demonstrate that PP1A (catalytic subunit of protein phosphatase-1) interacts with and dephosphorylates YAP2 in vitro and in vivo, and PP1A-mediated dephosphorylation induces the nuclear accumulation and transcriptional activation of YAP2. Inhibition of PP1 by okadiac acid (OA) increases the phosphorylation at serine 127 and cytoplasmic translocation of YAP2 proteins, thereby mitigating its transcription activity. PP1A expression enhances YAP2βs pro-survival capability and YAP2 knockdown sensitizes ovarian cancer cells to cisplatin treatment. Conclusions/Significance: Our findings define a novel molecular mechanism that YAP2 is positively regulated by PP1mediate
Biochemical systems identification by a random drift particle swarm optimization approach
BACKGROUND: Finding an efficient method to solve the parameter estimation problem (inverse problem) for nonlinear biochemical dynamical systems could help promote the functional understanding at the system level for signalling pathways. The problem is stated as a data-driven nonlinear regression problem, which is converted into a nonlinear programming problem with many nonlinear differential and algebraic constraints. Due to the typical ill conditioning and multimodality nature of the problem, it is in general difficult for gradient-based local optimization methods to obtain satisfactory solutions. To surmount this limitation, many stochastic optimization methods have been employed to find the global solution of the problem. RESULTS: This paper presents an effective search strategy for a particle swarm optimization (PSO) algorithm that enhances the ability of the algorithm for estimating the parameters of complex dynamic biochemical pathways. The proposed algorithm is a new variant of random drift particle swarm optimization (RDPSO), which is used to solve the above mentioned inverse problem and compared with other well known stochastic optimization methods. Two case studies on estimating the parameters of two nonlinear biochemical dynamic models have been taken as benchmarks, under both the noise-free and noisy simulation data scenarios. CONCLUSIONS: The experimental results show that the novel variant of RDPSO algorithm is able to successfully solve the problem and obtain solutions of better quality than other global optimization methods used for finding the solution to the inverse problems in this study
Improved self-management skills in Chinese diabetes patients through a comprehensive health literacy strategy: study protocol of a cluster randomized controlled trial
Molecular epidemiology of measles viruses in China, 1995β2003
This report describes the genetic characterization of 297 wild-type measles viruses that were isolated in 24 provinces of China between 1995 and 2003. Phylogenetic analysis of the N gene sequences showed that all of the isolates belonged to genotype H1 except 3 isolates, which were genotype A. The nucleotide sequence and predicted amino acid homologies of the 294-genotype H1 strains were 94.7%β100% and 93.3%β100%, respectively. The genotype H1 isolates were divided into 2 clusters, which differed by approximately 2.9% at the nucleotide level. Viruses from both clusters were distributed throughout China with no apparent geographic restriction and multiple co-circulating lineages were present in many provinces. Even though other measles genotypes have been detected in countries that border China, this report shows that genotype H1 is widely distributed throughout the country and that China has a single, endemic genotype. This important baseline data will help to monitor the progress of measles control in China
Two Lysines in the Forkhead Domain of Foxp3 Are Key to T Regulatory Cell Function
Background: The forkhead box transcription factor, Foxp3, is master regulator of the development and function of CD4+CD25+ T regulatory (Treg) cells that limit autoimmunity and maintain immune homeostasis. The carboxyl-terminal forkhead (FKH) domain is required for the nuclear localization and DNA binding of Foxp3. We assessed how individual FKH lysines contribute to the functions of Foxp3 in Treg cells. Methodology/Principal Findings: We found that mutation of FKH lysines at position 382 (K17) and at position 393 (K18) impaired Foxp3 DNA binding and inhibited Treg suppressive function in vivo and in vitro. These lysine mutations did not affect the level of expression of Foxp3 but inhibited IL-2 promoter remodeling and had important and differing effects on Treg-associated gene expression. Conclusions/Significance: These data point to complex effects of post-translational modifications at individual lysines within the Foxp3 FKH domain that affect Treg function. Modulation of these events using small molecule inhibitors ma
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