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排序方式: 共有423条查询结果,搜索用时 31 毫秒
411.
Insulin administration can increase muscle glycogen by utilising hyperinsulinaemic clamps prior to sports events or during the recovery phases, and increase muscle size by its chalonic action to inhibit protein breakdown. In order to control insulin abuse in equine sports, a method to detect effectively the use of insulins in horses would be required. Besides the readily available human insulin and its synthetic analogues, structurally similar insulins from other species can also be used as doping agents. This study describes a method for the simultaneous detection of bovine, porcine and human insulins, as well as the synthetic analogues Humalog (Lilly) and Novolog (Novo Nordisk) in equine plasma. Insulins were isolated from equine plasma by immunoaffinity purification, followed by centrifugal filtration, and analysed by nano-liquid chromatography-tandem mass spectrometry (LC/MS/MS). Insulin and analogues were detected and confirmed by comparing their retention times and major product ions. All five insulins (human insulin, Humalog, Novolog, bovine insulin and porcine insulin), which are exogenous in the horse, could be detected and confirmed at 0.05ng/mL. This method was successful in confirming the presence of human insulin in plasma collected from horses up to 4h after having been administered a single low dose of recombinant human insulin (Humulin R, Eli Lilly). To our knowledge, this is the first identification of exogenous insulin from post-administration horse plasma samples. 相似文献
412.
Marília A.R. Buzalaf Aline L. Leite Maria H.C. Rodrigues Daniela B. Niconielo Vanessa E.S. Cardoso 《Journal of fluorine chemistry》2008,129(8):691-694
A double-bind cross-over study was conducted on four healthy subjects, aged 19-29 years, in order to determine the relative bioavailability and other pharmacokinetics features of fluoride (F) after single oral administration in fasting conditions of 2 mg F as sodium F (NaF) or sodium monofluorophosphate (MFP). The bioavailability was evaluated on the basis of the plasma levels and of the urinary excretion of F. Blood was sampled before and during the 8 h after the administration of the test solutions. For F excretion urine was sampled 12 h before the study and over the 8 h after the administration. Data were tested for statistically significant differences by ANOVA and Tukey's post hoc tests, and also by Student's t-test (p < 0.05). For the two formulations, the pharmacokinetics of F in plasma was characterized by a rapid absorption and by a peak (Cmax = 0.1 μg/mL) which was reached 20 min after administration, followed by a biphasic elimination. In the 8 h following the administration the urinary excretion of F accounted for 35-41% of the administered dose, without significant differences between the two formulations. The AUCs (±S.D.) for NaF and MFP were 21.15 (±0.58) and 19.04 (±1.75) min μg mL−1, respectively, and were not significantly different (p = 0.079). Based on the AUC and Cmax of F in plasma and on the urinary excretion of F during the 8 h following administration, the relative bioavailabilities of the two F formulations were equivalent. 相似文献
413.
In this work, an amperometric sensor for nitrite detection based on a glassy carbon electrode modified with copper tetrasulphonated phthalocyanine immobilized by polycationic poly-L-lysine film is presented. The modified electrode showed an excellent catalytic activity toward nitrite oxidation. A linear response range from 0.12 up to 12.20 micromol L(-1) was obtained with a sensitivity of 0.83 microA L micromol(-1). The detection limit for nitrite was 36 nmol L(-1). The repeatability of the proposed sensor, evaluated in terms of relative standard deviation, was 1% for 10 measurements of 10 micromol L(-1) nitrite solution. Finally, the developed sensor was applied for nitrite determination in water samples and the results were in agreement to the comparative method. The average recovery for the samples was 101 (+/-4)%. 相似文献
414.
Meermann B Bockx M Laenen A Van Looveren C Cuyckens F Vanhaecke F 《Analytical and bioanalytical chemistry》2012,402(1):439-448
The aim of this work was speciation analysis of metabolites in feces samples collected within a clinical study during which
a bromine-containing anti-tuberculosis drug (TMC207) was administered to patients with multi-drug resistant tuberculosis infection.
Owing to slow elimination of the drug, no 14C label was used within this study. Quantification of the bromine species was accomplished using high performance liquid chromatography
coupled to inductively coupled plasma–mass spectrometry (HPLC/ICP-MS) in combination with on-line isotope dilution (on-line
ID), while structural elucidation of the species was performed using HPLC coupled to electrospray ionization–mass spectrometry.
The ICP-MS-based method developed shows a good intra- and inter-day reproducibility (relative standard deviation = 3.5%, N = 9); the limit of detection (1.5 mg TMC207 L−1) is of the same order of magnitude as that for HPLC/radiodetection; the dynamic range of the method covers more than two
orders of magnitude. Furthermore, the column recovery was demonstrated to be quantitative (recoveries between 90.6% and 99.5%).
Based on the excellent figures of merit, the “cold” HPLC/ICP-MS approach could be deployed for the actual human in vivo metabolism study, such that exposure of the human volunteers to the 14C radiolabel was avoided. 相似文献
415.
Protein adsorption onto capillary wall often hampers CE separations, particularly in the CZE mode. Electrostatic interactions are not the only factors affecting adsorption, as hydrophobic interactions and/or protein conformational changes are also involved in the adsorption phenomenon. Numerous methods can be used to reduce or avoid adsorption, such as (i) addition of low molecular weight molecules in the BGE, (ii) use of surfactants, or (iii) capillary coatings. However, most of these methods are not MS-compatible. In this study, we evaluated the addition of organic solvent as an alternative MS-compatible method to decrease protein adsorption. The effect of the solvent addition was emphasized using classical methods for estimating reversible and irreversible adsorption. In many cases, organic solvents were effective at decreasing adsorption. However, the influence of the organic solvent on protein adsorption should be evaluated case-by-case in CE method development. 相似文献
416.
Aline Mara B. Pires Silvia Y. Eguchi Maria Helena Andrade Santana 《Applied biochemistry and biotechnology》2010,162(8):2125-2135
This study aimed to evaluate the influence of the culture medium supplementation with mineral ions, focusing on the growth
of Streptococcus zooepidemicus as well as on the production and average molecular weight (MW) of hyaluronic acid (HA). The ions were investigated in terms
of individual absence from the totally supplemented medium (C+) or individual presence in the non-supplemented medium (C−),
where C+ and C− were used as controls. Differences between the effects were analyzed using the Tukey's test at p < 0.05. The adopted criteria considered required the ions, whose individual absence attained at 80% or less of the C+ and
their individual presence was 20% or more than the C−. The supplementation was either inhibitory or acted in synergy with
other ions, when the individual absence or presence was 20% higher than C+ or 20% lower than C−, respectively. Results showed
that the effects of C+ or C− were equal for both the production of HA and its yield from glucose. However, C+ showed to be
beneficial to cell growth while the individual absence of Na+ was beneficial to the production of HA. The highest MW of HA (7.4 × 107 Da) was observed in the individual presence of Na+ in spite of the lowest HA concentration (0.65 g.L−1). These results suggest that the quality of HA can be modulated through the mineral ion supplementation. 相似文献
417.
Aline Gégout Dr. Jean‐François Nierengarten Prof. Dr. Béatrice Delavaux‐Nicot Dr. Carine Duhayon Dr. Alix Saquet Dr. Andrea Listorti Dr. Abdelhalim Belbakra Claudio Chiorboli Dr. Nicola Armaroli Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(35):8825-8833
Diethylamino‐substituted oligophenylenevinylene (OPV) building blocks have been prepared and used for the synthesis of two [60]fullerene–OPV dyads, F‐D1 and F‐D2 , which exhibit different conjugation length of the OPV fragments. The electrochemical properties of these acceptor–donor dyads have been studied by cyclic voltammetry. The first reduction is always assigned to the fullerene moiety and the first oxidation centered on the diethylaniline groups of the OPV rods, thus making these systems suitable candidates for photoinduced electron transfer. Both the OPV and the fullerene‐centered fluorescence bands are quenched in toluene and benzonitrile, which suggests the occurrence of photoinduced electron transfer from the amino‐substituted OPVs to the carbon sphere in the dyads in both solvents. By means of bimolecular quenching experiments, transient absorption spectral fingerprints of the radical cationic species are detected in the visible (670 nm) and near‐IR (1300–1500 nm) regions, along with the much weaker fullerene anion band at λmax=1030 nm. Definitive evidence for photoinduced electron transfer in F‐D1 and F‐D2 comes from transient absorption measurements. A charge‐separated state is formed within 100 ps and decays in less than 5 ns. 相似文献
418.
For a prime number p let G be a profinite p-PD
n
group with a closed normal subgroup N such that G/N is a profinite p-PD
m
group and that H
i
(V, $
\mathbb{F}
$
\mathbb{F}
p
) is finite for every open subgroup V of N and all i ≤ [n/2]. Generalising [12, Thm. 3.7.4] we show that m ≤ n and N is a profinite p-PD
n − m
group.
In case that G is a pro-p
PD
n
group of Euler characteristic 0 with a closed normal subgroup N of type FP
[n−1 / 2] such that G/N is soluble-by-finite pro-p group of finite rank, we show that N is a pro-p
PD
n − m
group, where m = vcd
p
(G/N). As a corollary we obtain that a pro-p
PD
3 group with infinite abelianization is either soluble or contains a free nonprocyclic pro-p subgroup. 相似文献
419.
Aline M. F. Lima Anthony W. Musumeci Hong-Wei Liu Eric R. Waclawik Glaura G. Silva 《Journal of Thermal Analysis and Calorimetry》2009,97(1):257-263
High resolution thermogravimetry has been used to evaluate the carbonaceous content in a commercial sample of single-walled
carbon nanotube (SWNT). The content of SWNTs in the sample was found to be at least 77 mass% which was supported by images
obtained with scanning and transmission electron microscopies (SEM and TEM). Furthermore, the influence of SWNT addition on
the thermal stability of graphite in mixtures of SWNT/graphite at different proportions was investigated. The graphite stability
decreased with the increased of SWNT content in the overall range of composition. This behavior could be due to the close
contact between these carbonaceous species as determined by SEM analysis. 相似文献
420.
AT Toci P Crupi G Gambacorta T Dipalmo D Antonacci A Coletta 《Journal of mass spectrometry : JMS》2012,47(9):1104-1112
Negroamaro is an autochthonous wine grape variety of Southern Italy, which is becoming very important for the Italian wine market. The wine aroma is primary affected by the chemical composition of grapes, which can be influenced also by agronomic practices such as soil management. In this study, the free and bound aroma characterization was performed by gas chromatography-mass spectrometry analyses, and the influence of two soil managements (cover cropping and soil tillage) was evaluated. A total of 40 volatile compounds were observed in the wine samples. Alcohols (55.7?mg/L), fatty acids (7.0?mg/L) and esters (6.6?mg/L) were found as the main classes in Negroamaro wine. The results showed that the aroma composition of Negroamaro wine was positively affected by soil tillage probably because of the higher water stress (ψ(s) ) recorded in the vines from this treatment. Indeed, among the free volatile compounds, higher contents of esters, carboxylic acids, alcohols, phenolics and acetamides together with lower contents of sulfurs compounds were found in soil tillage wine. Conversely, no difference was observed in glycoside volatile compounds. Copyright ? 2012 John Wiley & Sons, Ltd. 相似文献