766 research outputs found
Rigidity properties of a three-way prestressed segmented ceramic plate
Rigidity properties of three way prestressed segmented ceramic plat
Bending-stiffness Properties of a Prestressed Segmented Ceramic Plate
Bending, twisting, and Poisson stiffness of prestressed segmented ceramic plat
Precise Switching of Flagellar Gene Expression in Escherichia Coli by the FlgM–FliA Regulatory Network
A remarkable feature of flagellar synthesis in Escherichia coli is that gene expression is sequential and
coupled to the assembly process. The interaction of two key proteins, the flagellar sigma factor FliA and
its anti-sigma factor FlgM serves as a major checkpoint in the assembly process that temporally separates
middle and late gene expression. While the sequential nature within each gene class has been studied
using large-scale transcriptional data, much less is known about the timing controlled by the checkpoint
mechanism. In this article, we analyze timing, sensitivity and robustness of the FlgM–FliA core regulatory
mechanism based on quantitative molecule data and a detailed stochastic as well as reduced deterministic
reaction kinetics model. We find that the pool of free anti-sigma factor FlgM, accumulated during middle
gene expression, acts as a molecular timer that determines the delay between successful completion of the
hook basal body subunit and the start of expression of flagellar filament proteins. Furthermore, we find
that the number of free FliA molecules needs to be tightly controlled for a precise switch from middle
to late gene expression. A sensitivity analysis based on the reduced reaction kinetics model reveals that
the checkpoint mechanism is very sensitive to changes in levels of competing sigma factors, allowing the
bacterium to rapidly adapt to a changing environment. In addition, we find that the reduced model also
shows a high sensitivity to the effective synthesis rates of FliA and FlgM. However, this high sensitivity
does not generally carry over to the original parameters of transcriptional and translational processes
in the detailed model. As a consequence, care has to be taken whenever interpreting results from the
robustness analysis of reaction kinetic models comprising lumped or effective parameters
Sloan/Johnson-Cousins/2MASS Color Transformations for Cool-Stars
We present multi-color transformations and photometric parallaxes for a
sample of 40 low mass dwarfs selected from the Sloan Digital Sky Survey (SDSS)
and the General Catalog of Trigonometric Stellar Parallaxes. Our sample was
re-observed at the Manastash Ridge Observatory (MRO) using both Sloan and
Johnson-Cousin filters and color transformations between the two photometric
systems were derived. A subset of the sample had previously measured
Johnson-Cousins photometry and parallaxes as well as 2MASS photometry. We
observed these stars at MRO using Sloan filters and used these data to derive
photometric parallax relations as well as SDSS/Johnson-Cousins/2MASS color
transformations. We present the data and derived transformations for use in
future low mass star studies.Comment: 7 pages, Accepted for publication in PAS
A Method for Combining Isolates of Phytophthora sojae to Screen for Novel Sources of Resistance to Phytophthora Stem and Root Rot in Soybean
Soybean cultivars with specific single resistance genes (Rps) are grown to reduce yield loss due to Phytophthora stem and root rot caused by the oomycete pathogen Phytophthora sojae. To identify novel Rps loci, soybean lines are often screened several times, each time with an isolate of P. sojae that differs in virulence on various Rps genes. The goal of this study was to determine whether several isolates of P. sojae that differ in virulence on Rpsgenes could be combined into a single source of inoculum and used to screen soybean lines for novel Rps genes. A set of 14 soybean differential lines, each carrying a specific Rps gene, was inoculated with three isolates of P. sojae, which differed in virulence on 6 to 10 Rps genes, individually or in a 1:1:1 mixture. Inoculum containing the 1:1:1 mixture of isolates was virulent on 13 Rps genes. The mixed-inoculum method was used to screen 1,019 soybean accessions in a blind assay for novel sources of resistance. In all, 17% of Glycine max accessions and 11% of G. soja accessions were resistant (≤30% dead plants), suggesting that these accessions may carry a novel Rps gene or genes. Advantages of combining isolates into a single source of inoculum include reduced cost, ability to screen soybean germplasm with inoculum virulent on all known Rps genes, and ease of identifying novel sources of resistance. This study is a precursor to identifying novel sources of resistance to P. sojae in soybean using RXLR effectors
Assessment of a Large-Scale Unbiased Malignant Pleural Effusion Proteomics Study of a Real-Life Cohort
Background: Pleural effusion (PE) is common in advanced-stage lung cancer patients
and is related to poor prognosis. Identification of cancer cells is the standard method for the
diagnosis of a malignant PE (MPE). However, it only has moderate sensitivity. Thus, more sensitive
diagnostic tools are urgently needed. Methods: The present study aimed to discover potential protein
targets to distinguish malignant pleural effusion (MPE) from other non-malignant pathologies. We
have collected PE from 97 patients to explore PE proteomes by applying state-of-the-art liquid
chromatography-mass spectrometry (LC-MS) to identify potential biomarkers that correlate with
immunohistochemistry assessment of tumor biopsy or with survival data. Functional analyses
were performed to elucidate functional differences in PE proteins in malignant and benign samples.
Results were integrated into a clinical risk prediction model to identify likely malignant cases.
Sensitivity, specificity, and negative predictive value were calculated. Results: In total, 1689 individual
proteins were identified by MS-based proteomics analysis of the 97 PE samples, of which 35 were
diagnosed as malignant. A comparison between MPE and benign PE (BPE) identified 58 differential
regulated proteins after correction of the p-values for multiple testing. Furthermore, functional
analysis revealed an up-regulation of matrix intermediate filaments and cellular movement-related
proteins. Additionally, gene ontology analysis identified the involvement of metabolic pathways
such as glycolysis/gluconeogenesis, pyruvate metabolism and cysteine and methionine metabolism.
Conclusion: This study demonstrated a partial least squares regression model with an area under the
curve of 98 and an accuracy of 0.92 when evaluated on the holdout test data set. Furthermore, highly
significant survival markers were identified (e.g., PSME1 with a log-rank of 1.68 × 10−6
).info:eu-repo/semantics/publishedVersio
Direct photonic coupling of a semiconductor quantum dot and a trapped ion.
Coupling individual quantum systems lies at the heart of building scalable quantum networks. Here, we report the first direct photonic coupling between a semiconductor quantum dot and a trapped ion and we demonstrate that single photons generated by a quantum dot controllably change the internal state of a Yb^{+} ion. We ameliorate the effect of the 60-fold mismatch of the radiative linewidths with coherent photon generation and a high-finesse fiber-based optical cavity enhancing the coupling between the single photon and the ion. The transfer of information presented here via the classical correlations between the σ_{z} projection of the quantum-dot spin and the internal state of the ion provides a promising step towards quantum-state transfer in a hybrid photonic network.We acknowledge support by the University of Cambridge,
the Alexander-von-Humboldt Stiftung, EPSRC
(EP/H005676/1), the European Research Council (Grant
numbers 240335 and 617985), EU-FP7 Marie Curie Initial
Training Networks COMIQ and S3NANO.This is the accepted manuscript. The final version is available at http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.123001
Qualitative Modelling in Embodiment Design - Investigating the Contact and Channel Approach Through Analysis of Projects
Purposeful qualitative modelling of embodiment function relations is a challenge in embodiment design. This contribution investigates the applicability and usefulness of the Contact and Channel Approach as a qualitative modelling approach in a survey study. From 23 development and research projects, advantages and challenges regarding applicability and usefulness are identified. A further result is that many different models are used additionally to the Contact and Channel Approach. Based on the findings, research potential for optimization and development of links to other models emerges
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