1,758 research outputs found
A three-dimensional particle method for violent sloshing under regular and irregular excitations
A three-dimensional (3D) numerical model is presented in the framework of Consistent Particle Method (CPM). The 3D gradient and Laplacian operators are derived based on Taylor series expansion, achieving good accuracy and largely alleviating the problem of spurious pressure fluctuation. An accurate boundary recognition scheme is introduced to determine the highly deformed free surface. Validated by our experimental studies of water sloshing under translational and rotational excitations, this model is shown to be robust and accurate in long time simulation of violent free surface flows which involve fluid merging and splitting. Using the validated numerical model, liquefied natural gas sloshing in a real ship under sea excitations is investigated. It is found that the sloshing waves in the beam sea sailing condition is the most violent and seriously affects the stability of ship motion. Various wave patterns under different excitations are discussed
Sequencing Pigeonpea Genome
Availability of draft genome has brought quantum jump in pigeonpea status and facilitated to move it to the league of genomic resource rich crops. It is important to mention that pigeonpea became the first orphan and non-industrial grain legume in 2012 to have the draft genome sequence. An elite pigeonpea genotype Asha (ICPL 87119) was used to develop the draft genome in two different sequencing efforts. The pigeonpea genome sequence effort led by International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) used Illumina Genome Analyzer and HiSeq 2000 NGS platform, and a total of 237.2 Gb of sequence was generated. De-novo genome assembly combined with Sanger-based bacterial artificial chromosome end sequences and a genetic map was used to assemble raw reads into scaffolds representing 72.7% (605.78 Mb) of the 833.07 Mb pigeonpea genome. Genome analysis predicted 48,680 genes with an average transcript length of 2348 bp, coding-sequence size of 959.35 bp and 3.59 exons per gene. Analysis of genome assembly for repetitive DNA showed presence of transposable elements (TEs) in 49.61% of assembled genome. The pigeonpea genome sequencing led by National Research Centre on Plant Biotechnology (NRCPB) used 454 GS-FLX sequencing chemistry, with mean read lengths of >550 bp and >10-fold genome coverage, was used to assemble ~511 Mb sequence data. In this study, 47,004 protein-coding genes were predicted. This study also reported 1213 disease resistance/defense response genes and 152 abiotic stress tolerance genes. The available pigeonpea draft genome information is expected to facilitate genomics-assisted breeding for the targeted traits that could improve food security in many developing countries
A biophysical model of the early olfactory system of honeybees
Experimental measurements often can only provide limited data from an animalβs sensory system. In addition, they exhibit large trial-to-trial and animal-to-animal variability. These limitations pose challenges to building mathematical models intended to make biologically relevant predictions. Here, we present a mathematical model of the early olfactory system of honeybees aiming to overcome these limitations. The model generates olfactory response patterns which conform to the statistics derived from experimental data for a variety of their properties. This allows considering the full dimensionality of the sensory input space as well as avoiding overfitting the underlying data sets. Several known biological mechanisms, including processes of chemical binding and activation of receptors, and spike generation and transmission in the antennal lobe network, are incorporated in the model at a minimal level. It can therefore be used to study how experimentally observed phenomena are shaped by these underlying biophysical processes. We verified that our model can replicate some key experimental findings that were not used when building it. Given appropriate data, our model can be generalized to the early olfactory systems of other insects. It hence provides a possible framework for future numerical and analytical studies of olfactory processing in insects
On single and double soft behaviors in NLSM
In this paper, we study the single and double soft behaviors of tree level
off-shell currents and on-shell amplitudes in nonlinear sigma model(NLSM). We
first propose and prove the leading soft behavior of the tree level currents
with a single soft particle. In the on-shell limit, this single soft emission
becomes the Adler's zero. Then we establish the leading and sub-leading soft
behaviors of tree level currents with two adjacent soft particles. With a
careful analysis of the on-shell limit, we obtain the double soft behaviors of
on-shell amplitudes where the two soft particles are adjacent to each other. By
applying Kleiss-Kuijf (KK) relation, we further obtain the leading and
sub-leading behaviors of amplitudes with two nonadjacent soft particles.Comment: 41 pages, 6 tables, 9 figures, minor revised, more content about
nonadjacent double soft limit, update the reference
A Nonaqueous Approach to the Preparation of Iron Phosphide Nanowires
Previous preparation of iron phosphide nanowires usually employed toxic and unstable iron carbonyl compounds as precursor. In this study, we demonstrate that iron phosphide nanowires can be synthesized via a facile nonaqueous chemical route that utilizes a commonly available iron precursor, iron (III) acetylacetonate. In the synthesis, trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) have been used as surfactants, and oleylamine has been used as solvent. The crystalline structure and morphology of the as-synthesized products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained iron phosphide nanowires have a typical width of ~16 nm and a length of several hundred nanometers. Structural and compositional characterization reveals a hexagonal Fe2P crystalline phase. The morphology of as-synthesized products is greatly influenced by the ratio of TOP/TOPO. The presence of TOPO has been found to be essential for the growth of high-quality iron phosphide nanowires. Magnetic measurements reveal ferromagnetic characteristics, and hysteresis behaviors below the blocking temperature have been observed
Regulation of HSP27 on NF-ΞΊB pathway activation may be involved in metastatic hepatocellular carcinoma cells apoptosis
<p>Abstract</p> <p>Background</p> <p>During the process of metastasis, cells are subjected to various apoptotic stimuli. Aberrant expression of apoptotic regulators often contribute to cell metastasis. Heat shock protein 27(HSP27) is confirmed as an apoptosis regulator, but its antiapoptotic mechanism in metastatic hepatocellular carcinoma (HCC) cells remains unclear.</p> <p>Methods</p> <p>Levels of HSP27 protein and its phosphorylation in Hep3B, MHCC97L to MHCC97H cells with different metastatic potentials were determined by western blot analysis. MHCC97H cells were transfected with specific small interference RNA (siRNA) against HSP27. The <it>in vitro </it>migration and invasion potentials of cells were evaluated by Transwell assay. The apoptosis ratio of MHCC97H cells was analyzed by TUNEL staining and Flow Cytometry. Alteration of signal transduction pathway after HSP27 knockdown in MHCC97H cells was evaluated through a Human Q Series Signal Transduction in Cancer Gene Array analysis. Nuclear NF-ΞΊB contentration and endogenous IKK activity were demonstrated by ELISA assay. The association of IKKΞ±, IKKΞ², IΞΊBΞ± with HSP27 and the association between IKKΞ² and IKKΞ± in MHCC97H cells were determined by co-immunoprecipitation assay followed by western blot analysis.</p> <p>Results</p> <p>HSP27 protein and its phosphorylation increased in parallel with enhanced metastatic potentials of HCC cells. siRNA-mediated HSP27 knockdown in MHCC97H significantly suppressed cells migration and invasion <it>in vitro </it>and induced cell apoptosis; the prominently altered signal transduction pathway was NF-ΞΊB pathway after HSP27 knockdown in MHCC97H cells. Furthermore, inhibition of HSP27 expression led to a significant decrease of nuclear NF-ΞΊB contentration and endogenous IKK activity. In addition, HSP27 was associated with IKKΞ±, IKKΞ², IΞΊBΞ± in three HCC cells above. ELISA assay and western blot analysis also showed a decrease of the association between IKKΞ² and IKKΞ±, the association between phosphor-HSP27 and IKK complex, and an increase of total IΞΊBΞ± but reducing tendency of phosphor-IΞΊBΞ± when HSP27 expression was efficiently knocked down in MHCC97H cells.</p> <p>Conclusion</p> <p>Altogether, these findings revealed a possible effect of HSP27 on apoptosis in metastatic HCC cells, in which HSP27 may regulate NF-kB pathway activation.</p
Development and evaluation of a hand held computer based on-call pack for health protection out of hours duty: A pilot study
BACKGROUND: The on call service for health protection in most parts of the UK is provided by general public health consultants, registrars and nurses as the first tier of response backed up by medical consultants in health protection. The first tier responder usually carries a large bag of papers containing both local and national guidance on the management of common cases/incidents. An electronic on call pack may provide a suitable practical alternative to large paper based systems and help professionals deliver out of hours health protection advice and response to incidents. METHODS: We developed and piloted an electronic on call pack in Hertfordshire for use at the health protection unit level containing key local and national guidelines, contact information and useful references. The on-call pack was initially piloted using a laptop and more recently using a personal digital assistant (PDA). The use of the on-call pack was evaluated. RESULTS: Key advantages of the electronic system include reduced size, faster access to information that is clearly indexed and the relative ease of updating information. As part of the pilot, the electronic on call pack was presented to a local and regional training meeting with good response from participants using qualitative and quantitative methods. CONCLUSION: It is anticipated that with suitable evaluation this system can be adapted and utilised by other health protection practitioners. This system provides a fast, reliable and easily maintained source of information for the public health on-call team
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
Improvement of the liquid-chromatographic analysis of protein tryptic digests by the use of long-capillary monolithic columns with UV and MS detection
Optimisation of peak capacity is an important strategy in gradient liquid chromatography (LC). This can be achieved by using either long columns or columns packed with small particles. Monolithic columns allow the use of long columns at relatively low back-pressure. The gain in peak capacity using long columns was evaluated by the separation of a tryptic bovine serum albumin digest with an LCβUVβmass spectrometry (MS) system and monolithic columns of different length (150 and 750Β mm). Peak capacities were determined from UV chromatograms and MS/MS data were used for Mascot database searching. Analyses with a similar gradient slope for the two columns produced ratios of the peak capacities that were close to the expected value of the square root of the column length ratio. Peak capacities of the short column were 12.6 and 25.0 with 3 and 15Β min gradients, respectively, and 29.7 and 41.0 for the long column with 15 and 75Β min gradients, respectively. Protein identification scores were also higher for the long column, 641 and 750 for the 3- and 15-min gradients with the short column and 1,376 and 993 for the 15- and 75-min gradients with the long column. Thus, the use of long monolithic columns provides improved peptide separation and increased reliability of protein identification
Graphene Photonics and Optoelectronics
The richness of optical and electronic properties of graphene attracts
enormous interest. Graphene has high mobility and optical transparency, in
addition to flexibility, robustness and environmental stability. So far, the
main focus has been on fundamental physics and electronic devices. However, we
believe its true potential to be in photonics and optoelectronics, where the
combination of its unique optical and electronic properties can be fully
exploited, even in the absence of a bandgap, and the linear dispersion of the
Dirac electrons enables ultra-wide-band tunability. The rise of graphene in
photonics and optoelectronics is shown by several recent results, ranging from
solar cells and light emitting devices, to touch screens, photodetectors and
ultrafast lasers. Here we review the state of the art in this emerging field.Comment: Review Nature Photonics, in pres
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