2,441,533 research outputs found
Erythrocyte signal transduction pathways and their possible functions
No full textHuman erythrocytes are equipped with a diversity of receptors and effectors that mediate well-characterized signal transduction pathways in nonerythroid cells. Some of these erythrocyte components may be vestiges of signaling pathways critical to the functions of the erythrocyte's precursors but no longer needed in the mature erythrocyte. Other signaling elements, however, are likely involved in enabling the erythrocyte to detect and respond to the needs of other hematopoietic and endothelial cells with which it comes in contact
A multi-filter system for speech enhancement under low signal-to-noise ratios
No full textIn this paper, the problem of deteriorating performance of speech recognition under very low signal-to-noise ratios (SNR) is considered. In particular, for a given pre-trained speech recognizer and for a finite set of speech commands, we show that popular noise reduction methods have a mixed performance in speech recognition accuracy under very low SNR. Although most noise reduction methods are attempting to reduce speech distortion or to increase noise suppression, it does not necessarily improve speech recognition accuracy very much due to the complexity of the recognizer. We propose a new hybrid algorithm to optimize on the speech recognition accuracy directly by mixing different noise reduction methods together. We show that this method can indeed improve the accuracy significantl
The met and unmet needs of young people who have had a stroke [In: Proceedings of SRR p. 573]
No full textA 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Microbial biomass P dynamics and sequential P fractionation in high and low P fixing Kenyan soils
No full textWe tested how the incorporation of farmyard manure (FYM) and inorganic phosphorus (P), KH2PO4 fertilizer changed soil microbial biomass phosphorus (biomass Po and inorganic and organic P fractions) in high and low P fixing Kenyan soils. Four soil treatments were compared during 32 weeks of laboratory incubation: (i) Nil; (ii) FYM (10 g kg−1); (iii) KH2PO4 (2.5 g kg−1) (P); and (iv) FYM (10 g kg−1) + KH2PO4 (2.5 g P kg−1). Biomass P was determined by fumigation-extraction followed by resin extraction, and P availability determined using a modified Hedley P fractionation method. The addition of FYM + KH2PO4 only increased biomass P in the high P fixing soil. From a maximum of about 22.5 μg P g−1 soil (week 1), biomass P declined to 4.8 (week 2), increased steadily to week 16 (15.2), and then decreased to 9.7 μg P g−1 soil (week 32). Biomass P in the low P fixing soil, with higher fertility, resin P and organic matter concentrations did not show any significant change. The P fractions that changed the most relative to the control, were the resin, Po–HCO3 and P–OH (week 1 and 16). This difference was enhanced in the high P fixing soil but resin P was the same in that soil at week 16, and the reduction in Po–OH in the FYM + KH2PO4 treatment (162.4 μg P g−1) compared to the control (242.2 μg P g−1) was more pronounced. This indicates an enhancement of microbial activity in the high P fixing soil
Use of Fourier-Transform Infrared Spectroscopy for the Diagnosis of Failure of Transfer of Passive Immunity and Measurement of Immunoglobulin Concentrations in Horses
No full textBackground: The economic, accurate, and rapid screening of foals for failure of transfer of passive immunity (FPT) is essential to ensure timely intervention. Hypothesis: Infrared (IR) spectroscopy of foal sera and pattern recognition may be used to diagnose FPT and quantify serum IgG. Samples: Sera from 194 foals (24–72 hours) with serum immunoglobulin G (IgG) concentrations determined previously by radial immunodiffusion assay (RID) were used. Methods: IR spectra were recorded for the serum samples, and the data were randomly divided into training and independent test sets, each containing both FPT-positive (IgG <400 mg/dL) and non-FPT samples. A genetic optimal region selection algorithm and linear discriminant analysis were used to partition the training spectra, and the resulting classifier was then validated by comparing the IR-predicted FPT status for each of the test samples to that provided by the RID IgG assay. A quantitative IR-based assay for IgG was developed using partial least squares (PLS) and validated by testing its ability to predict IgG concentrations. Results: Specificity, sensitivity, and accuracy for the combined data were 92.5, 96.8, and 95.9%, respectively. Corresponding positive (88.1%) and negative predictive (98.0%) values determined a success rate of 95–97% as compared to RID-based IgG concentrations. The IR-based quantitative assay yielded correlation coefficients for IR spectroscopy versus RID-based IgG concentrations of 0.90 and 0.86 for the training and test sets, respectively. Conclusions and Clinical Importance: The overall performance of the IR-based test was similar to that of the colorimetric assay and was superior and more economic than other available tests.Christopher B. Riley, J.T. McClure, Sarah Low-Ying, and R. Anthony Sha
Measurement of prompt hadron production ratios in collisions at 0.9 and 7 TeV
No full textThe charged-particle production ratios pˉ/p , K −/K +, π −/π +, (p+pˉ)/(π++π−) , (K ++K −)/(π ++π −) and (p+pˉ)/(K++K−) are measured with the LHCb detector using 0.3 nb−1 of pp collisions delivered by the LHC at s√=0.9 TeV and 1.8 nb−1 at s√=7 TeV . The measurements are performed as a function of transverse momentum p T and pseudorapidity η. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio pˉ/p is also considered as a function of rapidity loss, Δy≡y beam−y, and is used to constrain models of baryon transport
The construct validity of the Subjective Index of Physical and Social Outcome (SIPSO) [In: Proceedings of SRR, p. 931]
No full textLow densities of epiphytic bacteria from the marine alga ulva australis inhibit settlement of fouling organisms
No full textBacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. However, the number of bacterial cells necessary to defend against fouling on the plant surface is not known. Pseudoalteromonas tunicata and Phaeobacter sp. strain 2.10 (formerly Roseobacter gallaeciensis) are marine bacteria often found in association with the alga Ulva australis and produce a range of extracellular inhibitory compounds against common fouling organisms. P. tunicata and Phaeobacter sp. strain 2.10 biofilms with cell densities ranging from 102 to 108 cells cm–2 were established on polystyrene petri dishes. Attachment and settlement assays were performed with marine fungi (uncharacterized isolates from U. australis), marine bacteria (Pseudoalteromonas gracilis, Alteromonas sp., and Cellulophaga fucicola), invertebrate larvae (Bugula neritina), and algal spores (Polysiphonia sp.) and gametes (U. australis). Remarkably low cell densities (102 to 103 cells cm–2) of P. tunicata were effective in preventing settlement of algal spores and marine fungi in petri dishes. P. tunicata also prevented settlement of invertebrate larvae at densities of 104 to 105 cells cm–2. Similarly, low cell densities (103 to 104cells cm–2) of Phaeobacter sp. strain 2.10 had antilarval and antibacterial activity. Previously, it has been shown that abundance of P. tunicata on marine eukaryotic hosts is low (<1 x 103 cells cm–2) (T. L. Skovhus et al., Appl. Environ. Microbiol. 70:2373-2382, 2004). Despite such low numbers of P. tunicata on U. australis in situ, our data suggest that P. tunicata and Phaeobacter sp. strain 2.10 are present in sufficient quantities on the plant to inhibit fouling organisms. This strongly supports the hypothesis that P. tunicata and Phaeobacter sp. strain 2.10 can play a role in defense against fouling on U. australis at cell densities that commonly occur in sit
Low Spring Constant Regulates P-Selectin-PSGL-1 Bond Rupture
No full textAbstractForced dissociation of selectin-ligand bonds is crucial to such biological processes as leukocyte recruitment, thrombosis formation, and tumor metastasis. Although the bond rupture has been well known at high loading rate rf (≥102pN/s), defined as the product of spring constant k and retract velocity v, how the low rf (<102pN/s) or the low k regulates the bond dissociation remains unclear. Here an optical trap assay was used to quantify the bond rupture at rf≤20pN/s with low k (∼10−3–10−2pN/nm) when P-selectin and P-selectin glycoprotein ligand 1 (PSGL-1) were respectively coupled onto two glass microbeads. Our data indicated that the bond rupture force f retained the similar values when rf increased up to 20pN/s. It was also found that f varied with different combinations of k and v even at the same rf. The most probable force, f*, was enhanced with the spring constant when k<47.0×10−3pN/nm, indicating that the bond dissociation at low rf was spring constant dependent and that bond rupture force depended on both the loading rate and the mechanical compliance of force transducer. These results provide new insights into understanding the P-selectin glycoprotein ligand 1 bond dissociation at low rf or k
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