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71.
Comparison of the effects of concentration, pH and anion species on astringency and sourness of organic acids 总被引:4,自引:1,他引:3
The separate effects of concentration, pH and anion species on intensity of
sourness and astringency of organic acids were evaluated. Judges rated
sourness and astringency intensity of lactic, malic, tartaric and citric
acid solutions at three levels of constant pH varying in normality and at
three levels of constant concentration varying in pH. To assess the
comparative sourness and astringency of the organic acid anions of study,
binary acid solutions matched in pH and titratable acidity were also rated.
As pH was decreased in equinormal solutions, both sourness and astringency
increased significantly (P < 0.001). By contrast, as the normality of
the equi-pH solutions was increased, only sourness demonstrated significant
increases (P < 0.001) while astringency remained constant or decreased
slightly. At the lowest normality tested, all solutions were more
astringent than sour (P < 0.05). Although lactic acid was found to be
significantly more sour than citric acid (P < 0.05), no other sourness
or astringency differences among the organic acid anions were noted. This
study demonstrates for the first time that astringency elicited by acids is
a function of pH and not concentration or anion species, and confirms that
sourness is independently influenced by concentration, pH and anion species
of the acid.
相似文献
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Willeke MC van Roon-Mom Barry A Pepers Peter AC 't Hoen Carola ACM Verwijmeren Johan T den Dunnen Josephine C Dorsman GertJan B van Ommen 《BMC molecular biology》2008,9(1):84
Background
Huntington's disease is a progressive autosomal dominant neurodegenerative disorder that is caused by a CAG repeat expansion in the HD or Huntington's disease gene. Although micro array studies on patient and animal tissue provide valuable information, the primary effect of mutant huntingtin will inevitably be masked by secondary processes in advanced stages of the disease. Thus, cell models are instrumental to study early, direct effects of mutant huntingtin. mRNA changes were studied in an inducible PC12 model of Huntington's disease, before and after aggregates became visible, to identify groups of genes that could play a role in the early pathology of Huntington's disease. 相似文献75.
The sugar binding activity of MR60, a mannose-specific shuttling lectin, requires a dimeric state 总被引:1,自引:0,他引:1
MR60 is an intracellular membrane protein which has been shown to act as a
mannoside specific lectin and to be identical to ERGIC-53, a protein
characteristic of the endoplasmic reticulum-Golgi apparatus- intermediate
compartment, acting as a shuttle. According to its primary sequence, this
MR60/ERGIC-53 protein contains a luminal domain including the carbohydrate
recognition domain, a stem, a transmembrane segment and a cytosolic domain.
The endogenous MR60/ERGIC-53 protein is spontaneously oligomeric, (dimers
and hexamers). In this paper, we study the relationship between the
oligomerization state and the sugar binding capacity by using recombinant
proteins. The expression of the recombinant proteins was evidenced by
immunocytochemistry and by immunoprecipitation followed by SDS-PAGE
analysis. The full size recombinant protein binds mannosides and is
oligomeric, up to the hexameric form. Two truncated proteins lacking the
transmembrane and the cytosolic domains were prepared and characterized. A
long one, containing the cysteine 466 close to the C-terminal end of the
recombinant protein but lacking the cysteine 475, close to the C- terminal
end of the native protein, does bind mannosides and forms dimers but no
higher oligomeric forms. A shorter one, lacking both the cysteines 466 and
475, does not bind mannosides and does not form dimers or higher polymers.
The two cysteines in the carbohydrate recognition domain (C190 and C230)
are not involved in the stabilization of oligomers. In conclusion, this
study shows that the luminal moiety of MR60/ERGIC-53 contains a device
allowing both its oligomeric pattern and its sugar binding capability.
相似文献
76.
C Melzer AC Borges F Knebel WS Richter W Combs G Baumann H Theres 《Cardiovascular ultrasound》2004,2(1):1-7
Background
Power Doppler (PD) has improved diagnostic capabilities of vascular sonography, mainly because it is independent from the angle of insonation. We evaluated this technique in a prospective comparison with conventional imaging, consisting in Duplex and Color Doppler, for the evaluation of Renal Artery (RA) stenosis.Methods
Sensitivity, specificity and predictive values of PD and conventional imaging were assessed in a blinded fashion on eighteen patients, 9 with angiographic evidence of unilateral RA stenosis (hypertensive patients) and 9 with angiographically normal arteries (control group). PD images were interpreted with an angiography-like criteria.Results
In the control group both techniques allowed correct visualization of 16 out of the 18 normal arteries (93% specificity). Only in five hypertensive patients RA stenosis was correctly identified with conventional technique (56% sensitivity and 86% negative predictive value); PD was successful in all hypertensive patients (100% sensitivity and negative predictive value), since the operators could obtain in each case of RA stenosis a sharp color signal of the whole vessel with a clear "minus" at the point of narrowing of the lumen. All results were statistically significant (p < 0.01).Conclusions
This study demonstrates that PD is superior to conventional imaging, in terms of sensitivity and specificity, for the diagnosis of RA stenosis, because it allows a clear visualization of the whole stenotic vascular lumen. Especially if it is used in concert with the other sonographic techniques, PD can enable a more accurate imaging of renovascular disease with results that seem comparable to selective angiography. 相似文献77.
Copper sulfate can cause different pathologies in different organ systems during development. We determined the effects of toxic levels of copper sulfate on brain development in term Hubbard broiler chicks using stereological and biochemical analyses. Hubbard broiler chicken eggs were divided into three groups: controls with no treatment, sham-treated animals and an experimental group. On day 1, 0.1 ml saline was injected into the air chambers of the sham and experimental groups. The experimental group received also 50 μg copper sulfate. At term (day 21), all chick brains were removed and their volumes were determined using the Cavalieri volume estimation. Parallel biochemical analyses were carried out for glutathione and malondialdehyde levels in the brain tissues as indicators of oxidative damage. With copper treatment, the mean brain volume (8079 μm3) was significantly decreased compared to both the control (10075 μm3) and sham (9547 μm3) groups. Copper treatment (143.8 nmol/g tissue) showed significantly decreased malondialdehyde levels compared to the control (293.6 nmol/g tissue) and sham groups (268.8 nmol/g tissue). Copper treatment (404.5 nmol/g tissue) showed significantly increased malondialdehyde levels compared to the control (158.6 nmol/g tissue) and sham (142.8 nmol/g tissue) groups. The morphological and biochemical parameters we measured demonstrated that in term Hubbard broiler chicks, toxic levels of copper sulfate cause developmental and oxidative brain damage. 相似文献
78.
Background
In microarray data analysis, factors such as data quality, biological variation, and the increasingly multi-layered nature of more complex biological systems complicates the modelling of regulatory networks that can represent and capture the interactions among genes. We believe that the use of multiple datasets derived from related biological systems leads to more robust models. Therefore, we developed a novel framework for modelling regulatory networks that involves training and evaluation on independent datasets. Our approach includes the following steps: (1) ordering the datasets based on their level of noise and informativeness; (2) selection of a Bayesian classifier with an appropriate level of complexity by evaluation of predictive performance on independent data sets; (3) comparing the different gene selections and the influence of increasing the model complexity; (4) functional analysis of the informative genes. 相似文献79.
Yasuyuki Kobayashi Jon T Giles Masaharu Hirano Isamu Yokoe Yasuo Nakajima Joan M Bathon Joao AC Lima Hitomi Kobayashi 《Arthritis research & therapy》2010,12(5):R171
Introduction
Rheumatoid arthritis (RA) is a multi-organ inflammatory disorder associated with high cardiovascular morbidity and mortality. We sought to assess cardiac involvement using a comprehensive cardiac magnetic resonance imaging (cMRI) approach and to determine its association with disease characteristics in RA patients without symptomatic cardiac disease. 相似文献80.
Timm Konold Yoon Hee Lee Michael J Stack Claire Horrocks Robert B Green Melanie Chaplin Marion M Simmons Steve AC Hawkins Richard Lockey John Spiropoulos John W Wilesmith Gerald AH Wells 《BMC veterinary research》2006,2(1):1-20