oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 30 )

2018 ( 30 )

2017 ( 38 )

2016 ( 39 )

Custom range...

Search Results: 1 - 10 of 14077 matches for " William Grosvenor "
All listed articles are free for downloading (OA Articles)
Page 1 /14077
Display every page Item
Biochemical enrichment and biophysical characterization of a taste receptor for L-arginine from the catfish, Ictalurus puntatus
William Grosvenor, Yuri Kaulin, Andrew I Spielman, Douglas L Bayley, D Lynn Kalinoski, John H Teeter, Joseph G Brand
BMC Neuroscience , 2004, DOI: 10.1186/1471-2202-5-25
Abstract: Both PHA-E and RCA-I almost exclusively labeled an 82–84 kDa protein band of an SDS-PAGE of solubilized barbel taste epithelial membranes. Further, both rhodamine-conjugated RCA-I and polyclonal antibodies raised to the 82–84 kDa electroeluted peptides labeled the apical region of catfish taste buds. Because of the specificity shown by RCA-I, lectin affinity was chosen as the first of a three-step procedure designed to enrich the presumed LGICR for L-Arg. Purified and CHAPS-solubilized taste epithelial membrane proteins were subjected successively to (1), lectin (RCA-I) affinity; (2), gel filtration (Sephacryl S-300HR); and (3), ion exchange chromatography. All fractions from each chromatography step were evaluated for L-Arg-induced ion channel activity by reconstituting each fraction into a lipid bilayer. Active fractions demonstrated L-Arg-induced channel activity that was inhibited by D-arginine (D-Arg) with kinetics nearly identical to those reported earlier for L-Arg-stimulated ion channels of native barbel membranes reconstituted into lipid bilayers. After the final enrichment step, SDS-PAGE of the active ion channel protein fraction revealed a single band at 82–84 kDa which may be interpreted as a component of a multimeric receptor/channel complex.The data are consistent with the supposition that the L-Arg receptor is a LGICR. This taste receptor remains active during biochemical enrichment procedures. This is the first report of enrichment of an active LGICR from the taste system of vertebrata.The initial event in taste transduction involves recognition of taste stimuli by plasma membrane-associated receptor proteins. These proteins are concentrated at the apical end of specialized neuro-epithelial cells (taste cells) found within multicellular end-organs known as taste buds [1,2]. The recognition binding sites for most taste stimuli face the exterior environment. The interaction of a taste stimulus with this recognition site triggers a chain of metabolic an
Determination and Validation of Markers for Heat-Induced Damage in Wool Proteins  [PDF]
Anita J. Grosvenor, James D. Morton, Jolon M. Dyer
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.36056
Abstract: Protein-based animal fibres of commercial importance are frequently exposed to elevated temperatures during processing treatments. Hydrothermal processes cause protein deterioration, impacting negatively on the value or condition of these materials. This study was designed to investigate hydrothermal damage in wool proteins at the molecular level. The effect of hydrothermal damage on Type I and II intermediate filament proteins (keratins) extracted from wool was characterised using advanced quantitative techniques based on isobaric iTRAQ labelling and mass spectrometry. Many native peptides were observed to be degraded and modified. Amongst these, twenty keratin peptides were observed to consistently degrade during hydrothermal exposure. These peptides acted as molecular markers of damage – specific indicators of the extent of heat-induced protein damage. This technology will be of value in assessing the severity of damage imparted after high temperature exposure of protein-based animal fibres such as wool and cashmere during processes such as dyeing and carbonising, or even after high temperature human hair treatments. The identification of molecular damage markers identified within wool and other materials provides a new route to sensitive and specific evaluation of the effects of protein deterioration. It is anticipated that the utilisation of such markers will facilitate the development of targeted approaches to minimising processing damage to high-value fibres and protein-based biomaterials.
Microcontroller-Based Process Monitoring Using Petri-Nets
Frankowiak MarcosR,Grosvenor RogerI,Prickett PaulW
EURASIP Journal on Embedded Systems , 2009,
Abstract: This paper considers the development of a Petri-net-based modelling tool as a mechanism for process and system monitoring. The use of Petri-nets, which has previously been largely based in the areas of systems modelling and simulation, is shown here to have great potential for deployment as a process monitoring and management application. Interfacing with real-world processes has been achieved in part by introducing a specific set of extensions to the original Petri-net concept. This work has resulted in the engineering of a tool that can be embedded within the process using a microcontroller platform. The potential for such systems to provide low cost, yet powerful process management tools, is becoming increasingly evident, particularly given the ever-improving capabilities of microcontrollers.
A study of the effect of overshooting deep convection on the water content of the TTL and lower stratosphere from Cloud Resolving Model simulations
D. P. Grosvenor, T. W. Choularton, H. Coe,G. Held
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2007,
Abstract: Simulations of overshooting, tropical deep convection using a Cloud Resolving Model with bulk microphysics are presented in order to examine the effect on the water content of the TTL (Tropical Tropopause Layer) and lower stratosphere. This case study is a subproject of the HIBISCUS (Impact of tropical convection on the upper troposphere and lower stratosphere at global scale) campaign, which took place in Bauru, Brazil (22° S, 49° W), from the end of January to early March 2004. Comparisons between 2-D and 3-D simulations suggest that the use of 3-D dynamics is vital in order to capture the mixing between the overshoot and the stratospheric air, which caused evaporation of ice and resulted in an overall moistening of the lower stratosphere. In contrast, a dehydrating effect was predicted by the 2-D simulation due to the extra time, allowed by the lack of mixing, for the ice transported to the region to precipitate out of the overshoot air. Three different strengths of convection are simulated in 3-D by applying successively lower heating rates (used to initiate the convection) in the boundary layer. Moistening is produced in all cases, indicating that convective vigour is not a factor in whether moistening or dehydration is produced by clouds that penetrate the tropopause, since the weakest case only just did so. An estimate of the moistening effect of these clouds on an air parcel traversing a convective region is made based on the domain mean simulated moistening and the frequency of convective events observed by the IPMet (Instituto de Pesquisas Meteorológicas, Universidade Estadual Paulista) radar (S-band type at 2.8 Ghz) to have the same 10 dBZ echo top height as those simulated. These suggest a fairly significant mean moistening of 0.26, 0.13 and 0.05 ppmv in the strongest, medium and weakest cases, respectively, for heights between 16 and 17 km. Since the cold point and WMO (World Meteorological Organization) tropopause in this region lies at ~15.9 km, this is likely to represent direct stratospheric moistening. Much more moistening is predicted for the 15–16 km height range with increases of 0.85–2.8 ppmv predicted. However, it would be required that this air is lofted through the tropopause via the Brewer Dobson circulation in order for it to have a stratospheric effect. Whether this is likely is uncertain and, in addition, the dehydration of air as it passes through the cold trap and the number of times that trajectories sample convective regions needs to be taken into account to gauge the overall stratospheric effect. Nevertheless, the results suggest a potentially significant role for convection in determining the stratospheric water content. Sensitivity tests exploring the impact of increased aerosol numbers in the boundary layer suggest that a corresponding rise in cloud droplet numbers at cloud base would increase the number concentrations of the ice crystals transported to the TTL, which had the effect of reducing the fall speeds
A study of the effect of overshooting deep convection on the water content of the TTL and lower stratosphere from Cloud Resolving Model simulations
D. P. Grosvenor,T. W. Choularton,H. Coe,G. Held
Atmospheric Chemistry and Physics Discussions , 2007,
Abstract: Simulations of overshooting, tropical deep convection using a Cloud Resolving Model with bulk microphysics are presented in order to examine the effect on the water content of the TTL (Tropical Tropopause Layer) and lower stratosphere. This case study is a subproject of the HIBISUCS (Impact of tropical convection on the upper troposphere and lower stratosphere at global scale) campaign, which took place in Bauru, Brazil (22° S), from the end of January to early March 2004. Comparisons between 2-D and 3-D simulations suggest that the use of 3-D dynamics is vital in order to capture the mixing between the overshoot and the stratospheric air, which caused evaporation of ice and resulted in an overall moistening of the lower stratosphere. In contrast, a dehydrating effect was predicted by the 2-D simulation due to the extra time, allowed by the lack of mixing, for the ice transported to the region to precipitate out of the overshoot air. Three different strengths of convection are simulated in 3-D by applying successively lower heating rates (used to initiate the convection) in the boundary layer. Moistening is produced in all cases, indicating that convective vigour is not a factor in whether moistening or dehydration is predicted, since the weakest case only just penetrated the tropopause. An estimate of the moistening effect of these clouds on an air parcel traversing a convective region is made based on the domain mean simulated moistening and the frequency of convective events observed by the IPMet (Instituto de Pesquisas Meteorológicas, Universidade Estadual Paulista) radar to have the same 10 dBZ echo top height as those simulated. These suggest a fairly significant mean moistening of 0.26, 0.13 and 0.05 ppmv in the strongest, medium and weakest cases, respectively, for heights between 16 and 17 km. Since the tropopause in this region is thought to lie at ~15.9 km, this is likely to represent direct stratospheric moistening. Much more moistening is predicted for the 15–16 km height range with increases of 0.85–2.8 ppmv predicted. However, it would be required that this air is lofted through the tropopause via the Brewer Dobson circulation in order for it to have a stratospheric effect. Whether this is likely is uncertain and, in addition, the dehydration of air as it passes through the cold trap and the number of times that trajectories sample convective regions needs to be taken into account to gauge the overall stratospheric effect. Nevertheless, the results suggest a potentially significant role for convection in determining the stratospheric wate
Microcontroller-Based Process Monitoring Using Petri-Nets
Marcos R. Frankowiak,Roger I. Grosvenor,Paul W. Prickett
EURASIP Journal on Embedded Systems , 2009, DOI: 10.1155/2009/282708
Abstract: This paper considers the development of a Petri-net-based modelling tool as a mechanism for process and system monitoring. The use of Petri-nets, which has previously been largely based in the areas of systems modelling and simulation, is shown here to have great potential for deployment as a process monitoring and management application. Interfacing with real-world processes has been achieved in part by introducing a specific set of extensions to the original Petri-net concept. This work has resulted in the engineering of a tool that can be embedded within the process using a microcontroller platform. The potential for such systems to provide low cost, yet powerful process management tools, is becoming increasingly evident, particularly given the ever-improving capabilities of microcontrollers.
Multicritical Symmetry Breaking and Naturalness of Slow Nambu-Goldstone Bosons
Tom Griffin,Kevin T. Grosvenor,Petr Horava,Ziqi Yan
Physics , 2013, DOI: 10.1103/PhysRevD.88.101701
Abstract: We investigate spontaneous global symmetry breaking in the absence of Lorentz invariance, and study technical Naturalness of Nambu-Goldstone (NG) modes whose dispersion relation exhibits a hierarchy of multicritical phenomena with Lifshitz scaling and dynamical exponents $z>1$. For example, we find NG modes with a technically natural quadratic dispersion relation which do not break time reversal symmetry and are associated with a single broken symmetry generator, not a pair. The mechanism is protected by an enhanced `polynomial shift' symmetry in the free-field limit.
Cascading Multicriticality in Nonrelativistic Spontaneous Symmetry Breaking
Tom Griffin,Kevin T. Grosvenor,Petr Horava,Ziqi Yan
Physics , 2015, DOI: 10.1103/PhysRevLett.115.241601
Abstract: Without Lorentz invariance, spontaneous global symmetry breaking can lead to multicritical Nambu-Goldstone modes with a higher-order low-energy dispersion $\omega\sim k^n$ ($n=2,3,\ldots$), whose naturalness is protected by polynomial shift symmetries. Here we investigate the role of infrared divergences and the nonrelativistic generalization of the Coleman-Hohenberg-Mermin-Wagner (CHMW) theorem. We find novel cascading phenomena with large hierarchies between the scales at which the value of $n$ changes, leading to an evasion of the "no-go" consequences of the relativistic CHMW theorem.
Scalar Field Theories with Polynomial Shift Symmetries
Tom Griffin,Kevin T. Grosvenor,Petr Horava,Ziqi Yan
Mathematics , 2014, DOI: 10.1007/s00220-015-2461-2
Abstract: We continue our study of naturalness in nonrelativistic QFTs of the Lifshitz type, focusing on scalar fields that can play the role of Nambu-Goldstone (NG) modes associated with spontaneous symmetry breaking. Such systems allow for an extension of the constant shift symmetry to a shift by a polynomial of degree $P$ in spatial coordinates. These "polynomial shift symmetries" in turn protect the technical naturalness of modes with a higher-order dispersion relation, and lead to a refinement of the proposed classification of infrared Gaussian fixed points available to describe NG modes in nonrelativistic theories. Generic interactions in such theories break the polynomial shift symmetry explicitly to the constant shift. It is thus natural to ask: Given a Gaussian fixed point with polynomial shift symmetry of degree $P$, what are the lowest-dimension operators that preserve this symmetry, and deform the theory into a self-interacting scalar field theory with the shift symmetry of degree $P$? To answer this (essentially cohomological) question, we develop a new graph-theoretical technique, and use it to prove several classification theorems. First, in the special case of $P=1$ (essentially equivalent to Galileons), we reproduce the known Galileon $N$-point invariants, and find their novel interpretation in terms of graph theory, as an equal-weight sum over all labeled trees with $N$ vertices. Then we extend the classification to $P>1$ and find a whole host of new invariants, including those that represent the most relevant (or least irrelevant) deformations of the corresponding Gaussian fixed points, and we study their uniqueness.
Does breast magnetic resonance imaging measurement correlate with pathology in assessment of primary breast cancer?
AN Khan, M Hoosein, H Khan, L Grosvenor, M Al-Attar
Breast Cancer Research , 2009, DOI: 10.1186/bcr2373
Abstract: Retrospectively, patients with breast cancer who underwent MRI of the breast between 2006 and 2009 were identified from the Radiology Information System database. The maximum dimension of breast lesion on MRI was recorded by two breast radiologists and all lesions were 'T' staged. Correlation between MRI and histological measurement was performed using SPSS version 14.0. Measurement agreement by MRI and histology was analysed using the Bland and Altman (B&A) plot.This study included 98 patients. The mean size on MRI was 27 mm and that on histology was 28.87 mm. On the basis of MRI, 43 cases were classified as T1, 48 as T2 and 7 as T3. There was significant correlation between the MRI and histological measurements, with a correlation coefficient of 0.770 (P = 0.0001) and R2 value of 0.594. On B&A analysis the arithmetic mean difference (AMD) between MRI and histological measurements was 1.86 mm but the limits of agreement (LOA) were -24.5 to 28 mm. T stage comparison on B&A plot showed an AMD of -4.6 mm (LOA -28 to 18.9 mm) for T1, 1.25 mm (LOA -22.9 to 25.4 mm) for T2 and -6.42 mm (LOA -53 to 40 mm) for T3.A high degree of correlation exists between breast MRI and histological measurement using correlation coefficients. However, on B&A plot there is significant over and underestimation of T stage by MRI.
Page 1 /14077
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.