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391.
David M. G. Anderson Vikki A. Carolan Susan Crosland Kate R. Sharples Malcolm R. Clench 《Rapid communications in mass spectrometry : RCM》2009,23(9):1321-1327
Matrix‐assisted laser desorption/ionisation mass spectrometry imaging (MALDI‐MSI) has been used to image the distribution of the pesticide nicosulfuron (2‐[[(4,6‐dimethoxypyrimidin‐2‐yl)aminocarbonyl]aminosulfonyl]‐N,N‐dimethyl‐3‐pyridinecarboxamide) in plant tissue using direct tissue imaging following root and foliar uptake. Sunflower plants inoculated with nicosulfuron were horizontally sectioned at varying distances along the stem in order to asses the extent of translocation; uptake via the leaves following foliar application to the leaves and uptake via the roots from a hydroponics system were compared. An improved sample preparation methodology, encasing samples in ice, allowed sections from along the whole of the plant stem from the root bundle to the growing tip to be taken. Images of fragment ions and alkali metal adducts have been generated that show the distribution of the parent compound and a phase 1 metabolite in the plant. Positive and negative controls have been included in the images to confirm ion origin and prevent false‐positive results which could originate from endogenous compounds present within the plant tissue. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
392.
Paul N. Carding Sue Roulstone Kate Northstone ALSPAC Study Team 《Journal of voice》2006,20(4):623-630
There is only very limited information on the prevalence of voice disorders, particularly for the pediatric population. This study examined the prevalence of dysphonia in a large cohort of children (n = 7389) at 8 years of age. Data were collected within a large prospective epidemiological study and included a formal assessment by one of five research speech and language therapists as well as a parental report of their child's voice. Common risk factors that were also analyzed included sex, sibling numbers, asthma, regular conductive hearing loss, and frequent upper respiratory infection. The research clinicians identified a dysphonia prevalence of 6% compared with a parental report of 11%. Both measures suggested a significant risk of dysphonia for children with older siblings. Other measures were not in agreement between clinician and parental reports. The clinician judgments also suggested significant risk factors for sex (male) but not for any common respiratory or otolaryngological conditions that were analyzed. Parental report suggested significant risk factors with respect to asthma and tonsillectomy. These results are discussed in detail. 相似文献
393.
Kate McLeod Roger St.C. Smart Nicolas H. Voelcker Ron Sekel 《Applied Surface Science》2006,253(5):2644-2651
This paper reports the use of X-ray photoelectron spectroscopy (XPS) to investigate bisphosphonate (BP) adsorption onto plasma sprayed hydroxyapatite (HA) coatings commonly used for orthopaedic implants. BPs exhibit high binding affinity for the calcium present in HA and hence can be adsorbed onto HA-coated implants to exploit their beneficial properties for improved bone growth at the implant interface. A rigorous XPS analysis of pamidronate, a commonly used nitrogenous BP, adsorbed onto plasma sprayed HA-coated cobalt-chromium substrates has been carried out, aimed at: (a) confirming the adsorption of this BP onto HA; (b) studying the BP diffusion profile in the HA coating by employing the technique of XPS depth profiling; (c) confirming the bioactivity of the adsorbed BP. XPS spectra of plasma sprayed HA-coated discs exposed to a 10 mM aqueous BP solution (pamidronate) for periods of 1, 2 and 24 h showed nitrogen and phosphorous photoelectron signals corresponding to the BP, confirming its adsorption onto the HA substrate. XPS depth profiling of the 2 h BP-exposed HA discs showed penetration of the BP into the HA matrix to depths of at least 260 nm. The bioactivity of the adsorbed BP was confirmed by the observed inhibition of osteoclast (bone resorbing) cell activity. In comparison to the HA sample, the HA sample with adsorbed BP exhibited a 25-fold decrease in primary osteoclast cells. 相似文献
394.
Kateřina Galejová Lucie Obalová Květuše Jirátová Kateřina Pacultová František Kovanda 《Chemical Papers》2009,63(2):172-179
The effect of pelleting pressure (0–10 MPa) during the preparation of Co-Mn-Al mixed oxide catalyst on its texture and activity
for N2O catalytic decomposition was examined for small grain sizes used in laboratory experiments, and for model industry catalyst
particles. Adsorption/desorption measurements of nitrogen, mercury porosimetry and helium pycnometry were used for detail
characterization of porous structure. A volume of micropores of about 20 mm3 g−1 was evaluated using modified BET equation. This value did practically not change with the increasing pelletization pressure
except that of the sample formed at the pressure of 10 MPa. Although an increase of pelleting pressure caused an increase
in bulk density and a decrease in pore size and pore volume of the prepared catalyst (resulting in lower values of N2O effective diffusion coefficient), no direct correlation between pelleting pressure used and catalyst activity has been found.
In contrary, estimation of the internal diffusion limitation according to the Weisz-Prater criterion indicated that even laboratory
experimental data obtained for catalyst grains with particle size lower than 0.315 mm pelletized at higher pressures could
be influenced by internal diffusion. Estimation of the internal mass transfer limitation in industrial catalyst particles
described by the effectiveness factor showed that effectiveness factor of about 0.07 and 0.2 can be obtained for spheres with
the radius of 1.5 mm and 0.5 mm, respectively, if pelleting pressure of about 6 MPa was used for the catalyst preparation.
Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May
2008. 相似文献
395.
G. Klein A. Rippel D. N. Prjanischnikow A. A. Schmuck W. Sutthoff H. Klienmann K. G. Stern Frhr v. Falkenhausen C. Neuberg E. Simon A. Winterstein H. P. Kaufmann E. H. Winterstein O. Dalmer H. Pringsheim Deodata Krüger J. Leibowitz W. Nathusius H. Nelson A. L. Winton Kate B. Winton R. Weidenhagen K. Bernhauer E. Glanzmann und T. Gordonoff 《Fresenius' Journal of Analytical Chemistry》1932,89(5-6):228-230
Ohne Zusammenfassung 相似文献
396.
Rodjana Burakham Supunnee Duangthong Lop Patimapornlert Narong Lenghor Suphaphorn Kasiwad Lalida Srivichai Somchai Lapanantnoppakhun Jaroon Jakmunee Kate Grudpan 《Analytical sciences》2004,20(5):837-840
A simple FI and two different SI systems have been investigated for the determination of paracetamol by employing a simple reagent for a nitrosation reaction. It is based on the on-line nitrosation of paracetamol with sodium nitrite in an acidic medium. The formed nitroso derivative species reacts further with sodium hydroxide to convert it to a more stable compound. The yellow product is continuously monitored at 430 nm. The FI system is very simple and cost effective for fast manual operation (60 injections/h; y = 0.268x + 44.314, r2 = 0.9910 for 400 - 1000 mg/l and y = 0.1687x + 145.72, r2 = 0.9970 for 1000 - 2500 mg/l). The two SI systems with different components and configurations are automated and optimized for the conditions for which no extra dilution is to be required for sample handling: one with a syringe pump and two selection valves (60 samples/h; y = 0.1488x - 4.7297, r2 = 0.9946 for 400 - 1000 mg/l and y = 0.0858x + 63.933, r2 = 0.9849 for 1000 - 2500 mg/l); the other is simpler and more cost-effective, with an autoburette and only one selection valve (15 samples/h; y = 0.0072x + 1.1467, r2 = 0.9977 for 200 - 1000 mg/l and y = 0.0028x + 5.4699, r2 = 0.9879 for 1000 - 2500 mg/l). They have all been applied to assay paracetamol in pharmaceutical preparations. The obtained results agree with those by the US Pharmacopeia method. 相似文献
397.
398.
Martin Pavlačka Petra Bajerová Kateřina Kortánková Jiří Bláha Michal Zástěra Roman Mázl Karel Ventura 《International Journal for Ion Mobility Spectrometry》2016,19(1):31-39
Characterization of ions from eight explosives (2,4,6-trinitrotoluene, pentaerythritol tetranitrate, 2,4,6-trinitrophenol, 2,4-dinitrotoluene, erythritol tetranitrate, hexamethylene triperoxide diamine, 2,4,6-trinitrophenylmethylnitramine and 1,3,5-trinitro-perhydro-1,3,5-triazine) using differential mobility spectrometry (DMS) with 63Ni as an ionization source was performed. Presented results of explosive analysis have been evaluated by use of special software tool which communicates with DMS in real time. This tool was developed for visualization, identification and comparison of measured data. Each explosive provides characteristic signal at a specific compensation voltage under a fixed dispersion field. Peaks in DMS spectra for these ions were confined to a range of compensation voltages between ?1.61 to +1.71 V at RF = 1060 V. We calculated specific alpha coefficients (α2 and α4) to obtain a nonlinear function of explosives, based on their DMS spectra. Dependence of mobility for measured explosives ions in electric field at E/N values between 0 to 120 Td were used to inspectional graphical differentiation of explosives. 相似文献
399.
The paper deals with the displacement washing of unbleached pulp cooked from rapeseed straw by soda pulping under laboratory conditions. Pulp fibres were characterised by their average length, as well as by effective specific volume and surface. Using the step function input change method, the washing breakthrough curves measured for alkali lignin as a tracer were described by the dispersed plug flow model containing a dimensionless criterion, the Péclet number. Besides the wash yield, the dispersion coefficient as well as the mean residence time and space time were evaluated. Preliminary results obtained for soda rapeseed pulp were compared with those for kraft hardwood (beech) and softwood (spruce, pine) pulps published earlier. The wash yield measured for soda pulp was found to be lower than that for hardwood and softwood pulps which manifested lower hydraulic resistance. The presence of silique valves in rapeseed straw resulted in lower mean residence time of lignin removed from the pulp bed in comparison with pulp manufactured from stalks only. 相似文献
400.
Verheij JB Wildhagen MF Hofstra RM Pals G Habbema JD ten Kate LP 《Community genetics》1999,2(2-3):74-81
OBJECTIVE: The aim of this study was to perform a prospective evaluation of the effects, costs and savings of a preconceptional screening programme of couples for carriers of cystic fibrosis (CF). METHODS: A decision model for both single-entry two-step (SETS) and double-entry two-step (DETS) couple screening was constructed. Two mutation detection methods were considered: allele-specific oligonucleotide (ASO) hybridisation screening of 32 mutations, with a sensitivity of 90%, and denaturing gradient gel electrophoresis (DGGE), with a sensitivity of 98%. In our model, the following combinations were used: (1) ASO for both steps; (2) DGGE for both steps, and (3) ASO for the first step and DGGE for the second step. The model is demonstrated using figures from the Netherlands, where there is a carrier frequency of 1:30. We estimated the value of different choices and probabilities in a decision tree and determined the costs of screening for CF and the costs of the illness itself. RESULTS: We found that with most of the combinations of mutation detection methods, SETS couple screening could offer positive net savings in the Netherlands. The ASO/DGGE combination resulted in the highest net savings. DETS couple screening for all combinations, including testing with DGGE in both steps, did not show a positive cost-savings balance at all, not even with an uptake rate of 100%. The maximum number of carrier couples identified when screening 100,000 couples with the ASO/DGGE combination was 98 (SETS). This could result in about 25 fewer children born with CF each year in the Netherlands, under the following assumptions: (1) each couple has two children and 10% of couples are unable to have children; (2) of detected carrier couples, 15% decide not to have children and 85% make use of prenatal diagnosis; (3) of those fetuses diagnosed with CF, 80% are aborted, and (4) prenatal diagnosis carries a 0.75% risk of iatrogenic abortion. CONCLUSIONS: The results of this evaluation show that there are no financial objections to the preconceptional screening of couples in the Netherlands when the above-mentioned assumptions apply; thus, further evaluation can concentrate on the balance of the non-economic consequences of screening for participants and for society. 相似文献