A slightly modified procedure of direct substoichiometric isotope dilution analysis is theoretically treated and its advantages are stated. The precision of one case of reverse isotope dilution is...
1. Standard radioisotope dilution techniques employing [3H]water and [22Na]sodium chloride have been used to determine the total body water and total exchangeable sodium of 20 male and 10 female normal Ghanaians (Africans) aged 19-25 years.. 2. Lean body mass and total body fat are calculated as a percentage of body weight; the total exchangeable sodium values have been expressed in relation to lean body mass.. 3. Comparison of the data for Ghanaian subjects with published figures for Caucasian subjects of similar age shows that the Ghanaian men have much less total body fat and the women a little less total body fat than their Caucasian counterparts.. 4. Total exchangeable sodium expressed in terms of lean body mass shows close agreement in both men and women. ...
Mercury speciation in solid sample matrices has been investigated using high performance liquid chromatography (HPLC) coupled with multicollector sector field (MCSF) and quadrupole (Q) inductively coupled plasma mass spectrometry (ICP-MS) for species specific isotope dilution mass spectrometry (IDMS). 199Hg enriched methylmercurychloride has been synthesised and recovered in the solid form for use as a spike material. The stability of methylmercury during the IDMS procedure was investigated using 199Hg and 13C labelled methylmercury isotopomers and ¹H Nuclear Magnetic Resonance spectroscopy. IntermoIecuJar exchange of the methylmercury halide counter ion was observed, the halide counter ion order of preference was l,Br,Cl. No evidence was found for the decomposition, or formation, of methylmercury during equilibration with soil (NIST2710 SRM) or dogfish muscle (DORM-2 CRM), or during chromatographic separation. The extent of equilibration between the spike and the particulate bound mercury ...
The measurement of total folate in clinical material became possible with the introduction of the Lactobacillus casei assay some 50 years ago. The use of lactoglobulin as a folate binding agent to measure folate by radioisotope dilution, later fluorimetry, is more user friendly but gives largely similar results.. The principal folate … ...
Science shouldnt be a term used loosely. It should, at minimum, be indicative of using a definitive method which includes observation, ask a question, form a hypothesis, analyze results, control groups, statistical methods, case study, and/or other avenues to come. ...
Isotope Dilution Mass Spectrometry (IDMS) has become an essential tool in research laboratories and is increasingly used in routine analysis labs (including environmental, food safety and clinical applications). This is the first textbook to present a comprehensive and instructive view of the theory and applications of this growing technique.The main objective of this book is to cover the theory and applications of Isotope Dilution in Analytical Chemistry. The scope is comprehensive to include elemental analysis, speciation analysis, organic analysis and biochemical and clinical analysis together with applications in metabolism studies and traceability of goods. Until now there have been no books published with the same general scope (only book chapters on particular applications). This is a textbook focused at post-graduate level covering the basic knowledge required for doctoral studies in this field. Isotope Dilution Mass Spectrometry will also outline practical applications of interest for routine
Isotope dilution analysis is a method of determining the quantity of chemical substances. In its most simple conception, the method of isotope dilution comprises the addition of known amounts of isotopically-enriched substance to the analyzed sample. Mixing of the isotopic standard with the sample effectively "dilutes" the isotopic enrichment of the standard and this forms the basis for the isotope dilution method. Isotope dilution is classified as a method of internal standardisation, because the standard (isotopically-enriched form of analyte) is added directly to the sample. In addition, unlike traditional analytical methods which rely on signal intensity, isotope dilution employs signal ratios. Owing to both of these advantages, the method of isotope dilution is regarded among chemistry measurement methods of the highest metrological standing. Analytical application of the radiotracer method is forerunner of isotope dilution. This method was developed in the early 20th century by George de ...
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Crivellari, Stefano; Chiessi, Cristiano Mazur; Kuhnert, Henning; Häggi, Christoph; Portilho-Ramos, Rodrigo Costa; Zeng, Jing-Ying; Zhang, Yancheng; Schefuß, Enno; Mollenhauer, Gesine; Hefter, Jens; Alexandre, Felipe; Mulitza, Stefan; Sampaio, Gilvan (2018): HS1 records bases on isotope, inorganic and organic geochemistry of sediment cores GeoB16224-1 and GeoB16212-2. PANGAEA, https://doi.org/10.1594/PANGAEA.887797, Supplement to: Crivellari, S et al. (2018): Increased Amazon freshwater discharge during late Heinrich Stadial 1. Quaternary Science Reviews, 181, 144-155, https://doi.org/10.1016/j.quascirev.2017.12.005
Callaghan, D. (1969). Some investigations of intramolecular screening effects on 1H and 19F N.M.R. chemical shifts. PHD thesis, Aston University. Cliffe, K.R. (1969). Studies of deposition on cooled tubes with special reference to coal-fired boilers. PHD thesis, Aston University. Cole, I.M. (1969). An investigation of the rolling of cylindrical tube by grooved roll. PHD thesis, Aston University. Conceicao, P.H. (1969). A study of stray load losses in core clamp plates of salient pole synchronous machines. Masters thesis, Aston University. Cooksey, B.G. (1969). Substoichiometry in isotope dilution analysis:automation of the process with reference to mercury. PHD thesis, Aston University. Costello, J. (1969). Flow and transfer processes at abrupt expansions. PHD thesis, Aston University. ...
A method for measuring local venous flow by a constant indicator dilution technique is described. The optimal conditions have been outlined and the accuracy tested in vitro and found to be within ±3%. When compared with direct measurements of venous flow in dogs, its accuracy was within ±5%. The method is safe, easy to perform and, with the catheters described, flow can be measured over ranges of 20 to 5,700 ml/min in any vein greater than 4 mm inner diameter in which the catheter tips can be introduced.. ...
NEW ZEALAND - A researcher at the Geological and Nuclear Sciences (GNS) National Isotope Centre has developed a test based on isotope analysis to distinguish between battery (cage) barn, free-range and organic eggs based on the hens diet.
Mass spectroscopy is increasingly used for measuring the presence and amounts of substances in samples, with applications in food, security, health and safety industries and is considered an excellent measurement tool. One of the methods used to identify multiple compounds in a sample is isotope dilution. However, this method does not account for the sample changes during the analysis and composition changes must be determined mathematically or by conducting multiple experiments. Due to this complexity, uptake of this advanced calibration approach is slow. Current algorithms to address simultaneous compound formation and degradation using multiple spiking isotope dilution mass spectrometry are extremely complex and do not result in explicit results nor reliable estimates of uncertainty in those results. Many algorithms give identical numerical results for the initial amount of substances in the sample, but the coefficients that describe the changes during the analysis differ.. There is a demand ...
Corrinoids from various ovine tissue samples (liver, blood, small intestinal fluid and faeces) were analysed using a combination of high-performance liquid chromatography (HPLC) and a radioisotope dilution assay (RIDA) to estimate the distribution of corrinoids - the cobalamins hydroxocobalamin (OH-cbl), methylcobalamin (me-cbl) and 5-deoxyadenosylcobalamin (ado-cbl), and cobalamin analogues - in these tissues. Samples were taken from either cobalt-deficient or cobalt-replete ewes, and ruminant and pre-ruminant lambs. In liver, ado-cbl predominated, followed by analogues, OH-cbl and me-cbl. Supplementation with either cobalt (ruminant) or vitamin B12 injections (pre-ruminant) increased the amount of ado-cbl and decreased analogues. In blood, OH-cbl predominated, followed by ado-cbl, analogues and me-cbl, respectively. In small intestinal fluid, the distribution from largest to smallest percentage was analogues, ado-cbl, OH-cbl and me-cbl. In faeces, analogues constituted the greatest proportion,
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1. Rat thymus cells were incubated in homologous serum (10%) and medium 199. The effects of various quantities of thymidine or deoxycytidine (0-30μm) on the radioactive labelling of cells with the corresponding radioactive deoxynucleoside were examined. From plots of the reciprocal of the radioactivity incorporated against the total deoxynucleoside concentration (`isotope-dilution plots), values were obtained for (a) the Vmax. of the rate-limiting step governing incorporation of the deoxynucleoside, and (b) the concentration of the pool of compounds competing with the radioactive deoxynucleoside at that rate-limiting step. From changes in these values under different experimental conditions inferences were drawn on the position and control of the rate-limiting step within intact cells. 2. Isotope-dilution plots for deoxycytidine were linear, whereas plots for thymidine were bimodal, indicating an abrupt increase in both the Vmax. and pool concentration at a critical thymidine concentration ...
Tracking cardiac output by a saline dilution technique using esophageal catheter electrodes.: This paper presents preliminary results of a study in which saline
Pleasure Convenient" is a clever smash-up of styles. At just over two minutes the track is primarily interested in an old-school d-beat attack with plenty of "playing Guitar Hero on expert level" drum fills. But no track on Isotope is merely how it begins. Like most of the compositions across this record, subtle complexity pops up like Punxsutawney Phil trying not to see his shadow after a long night of consuming way too much sweet vermouth on the rocks with a twist. As the track decays into a marching rhythm, heavy on the snare, a syncopated rhythm needles through the fracas to take center stage. Although brief, its a revealing look into the sheer breadth of influences that ended up being honored in a band that started out with the goal of sounding like ultimate Japanese old school band Bastard.. Rolling out with all the groove and authority of a Tragedy track, "Bloody Dove of Peace" represents a convergence of styles. The rhythm section bursts forward, coming off a roll on the toms to end the ...
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P32 and other tracer studies of eye information including symptoms, causes, diseases, symptoms, treatments, and other medical and health issues.
The study of blood-tissue exchange by the multiple indicator dilution technique often needs frequent sampling in the blood of the indicator dilution curves (IDC). Usually, this requires the use of a catheter supported by a pump. This causes a distortion in the IDC, which must be removed for proper interpretation of the data. A deconvolution-based methodology to remove IDC distortion is presented. First, the catheter impulse response is modelled by means of data obtained from a suitable experiment. Then the reconstruction of the blood IDC is tackled by a new nonparametric deconvolution algorithm, which provides (quasi) time-continuous signals and exploits statistically based criteria for the choice of the regularisation parameter. The methodology is applied to the removal of cathether distortion in studies of glucose blood-tissue exchange in the human forearm and myocardium.. ...
Strong distinctions in metabolite concentrations were found with the quantification strategies applied. For dilutions ranging from 1:2 to 1:20 internal calibration and isotope dilution mass spectrometry were found to be most suitable for the compensation of matrix effects. Further more, the results showed that U13C4-aspartate as internal standard could be used for various amino acids in the chromatographic run. Using isotope dilution, where each metabolite has its own labelled analogue, the linear range of the calibration curve and the coefficient of correlation (up to 0.9999) were improved. The procedure of standard addition was only necessary for very low concentrated metabolites. To avoid this time consuming procedure, samples can as well be concentrated and measured via internal calibration instead. External calibration was sufficient for biological samples in dilutions of 1:20 or higher, because the measurements were hardly influenced by matrix effects. ...
... ,12(S)-HETE-d8 is used as an internal standard for the quantification of 12(S)-HETE by stable isotope dilution mass spectrometry.,biological,biology supply,biology supplies,biology product
Converts the newer IDMS (isotope dilution mass spectrometry) serum creatinine assay to the older, conventional assay (eg, alkaline picrate).
Mangerich A., Veith S., Popp O., Fahrer J., Martello R., Bohr V.A., Bürkle A. (2012) Quantitative analysis of WRN exonuclease activity by isotope dilution mass spectrometry, Mechanisms of Ageing and Development, 133, 575-579 Nikolova T., Hennekes F., Bhatti A., Kaina B. (2012) Chloroethylnitrosourea-induced cell death and genotoxicity: cell cycle dependence and the role of DNA double-strand breaks, HR and NHEJ, Cell Cycle, 11, 2606-2619 Lillich M., Che X., Weil T., Barth H., Fahrer J. (2012) Streptavidin-conjugated C3 protein mediates the delivery of mono-biotinylated RNAse A into macrophages, Bioconjugate Chemistry, 23, 1426-1436 Meise R., Tomicic M.T., Kaina B., Christmann M. (2012) The chloroethylating anticancer drug ACNU induces FRA1 that is involved in drug resistance of glioma cells, Biochimica et Biophysica Acta, 1823, 1199-1207 Bauer M., Goldstein M., Heylmann D., Kaina B. (2012) Human monocytes undergo excessive apoptosis following temozolomide activating the ATM/ATR pathway while ...
Corcho Alvarado, J. A., R. Purtschert, J. Rüedi, H. H. Loosli, C. Chabault, F. Barbecot, L. Dever, W. Aeschbach-Hertig, R. Kipfer, 2003. Origin and temporal evolution of the groundwater in the Fontainebleau Sands Aquifer (France) investigated using 3H, 85Kr, 39Ar, 14C and stable noble gases. International Symposium on Isotope Hydrology and Integrated Water Resources Management, IAEA, Vienna, IAEA-CN-104/92: 105-106. ...
An important additional and evolving use of radioisotopes is in the treatment of disease.. There is a fundamental belief that cancer, leukemia, heart disease, Parkinsons disease, and more can be treated-and possibly cured-through the use of molecules that seek and attach radioisotopes to tumors and cancerous growths. Through this process, radioactivity can be delivered directly to the cells that require treatment, with minimal damage to nearby tissue.. NorthStar is well-positioned to meet the challenges ahead.. ...
Aridity and seasonality of precipitation are characteristics of the highland region in Bolivia. Groundwater becomes an important and safe source of water when surficial bodies are intermittent and affected by natural and anthropogenic contamination. Decades of exploitation of the Challapampa aquifer, combined with lack of information required to understand the groundwater circulation, represent a challenge for reservoir management. This study analyzes isotopic compositions of deuterium and oxygen-18 in different stages in the hydrologic cycle to assess flow patterns in the aquifer, especially in the alluvial fan of River Paria, where records are more extensive in space and time. Interpretations are based on existing and new data. Some implications, such as the age of water, the evaporation effect in groundwater and some thermal intrusions are supported by stable isotopes, tritium, radiocarbon, and electrical conductivity records. New results confirm that modern precipitation over the mountains
In most current designs of D-T fusion reactor blankets employing ceramic breeder materials, the use of a helium sweep gas containing 0.1 % of hydrogen is contemplated to extract tritium efficiently via isotopic exchange reactions. However, the isotope exchange reaction proceeds fast only at the more elevated temperatures, so that the rate of isotope exchange reactions is considerably low at lower temperatures. Taking into consideration that there is a broad temperature distribution within a blanket module, it is anticipated that the tritium bred in regions of lower temperatures will be poorly recovered. For this reason, there is still a need to develop techniques that contribute to the acceleration of the recovery of bred tritium at lower temperatures. In our previous works, the effect of catalytic active metal additives, such as Pt and Pd, on the heterogeneous isotope exchange reactions at the breeder-sweep gas interface was examined. The results indicate that the exchange reactions were ...
New strategies are needed to address the current and future shortages of radioisotopes that threaten medical research and treatment.
Keywords: Gross N biotransformation, soil microbial biomass, nitrogen availability, mineralisation, C:N ratios.. Summary:. Understanding the factors that govern microbial activities in soils is important, because the heterotrophic soil microbial biomass is driving the carbon (C) and nitrogen (N) cycling, and the net availability of N for plant uptake or losses. The processes by which C and N interact during decomposition of organic matter in soil, and the mineralisation-immobilisation turnover are well known but still difficult to predict, due to the complex interactions between soil micro-organisms and their substrates. The 15N isotope dilution techniques that allow rates of N transformations to be quantified accurately and simultaneously help the understanding of the effects of soil, crop and management conditions on microbial activities. The quantification of the relative importance of gross mineralisation, immobilisation and nitrification is also a key for understanding the competition ...
Keywords: Gross N biotransformation, soil microbial biomass, nitrogen availability, mineralisation, C:N ratios.. Summary:. Understanding the factors that govern microbial activities in soils is important, because the heterotrophic soil microbial biomass is driving the carbon (C) and nitrogen (N) cycling, and the net availability of N for plant uptake or losses. The processes by which C and N interact during decomposition of organic matter in soil, and the mineralisation-immobilisation turnover are well known but still difficult to predict, due to the complex interactions between soil micro-organisms and their substrates. The 15N isotope dilution techniques that allow rates of N transformations to be quantified accurately and simultaneously help the understanding of the effects of soil, crop and management conditions on microbial activities. The quantification of the relative importance of gross mineralisation, immobilisation and nitrification is also a key for understanding the competition ...
Iron is an essential element for the living organisms but free iron can be toxic. Iron metabolism disorders affect a large portion of human population. There exists a need for development of a reference technique to measure body iron stores. The ideal technique for determination of body iron stores would to measure ferritin concentration along with ferritin iron saturation. This study uses the principle of Isotope Dilution Mass Spectrometry (IDMS) to measure serum ferritin bound iron. IDMS requires the biosynthesis of a ferritin spike with isotopically enriched iron and sulphur. The aim of this project was to synthesize a ferritin spike for serum ferritin and ferritin bound iron quantification for development of a reference technique to determine body iron stores. This study involved the biosynthesis of a ferritin spike labelled with isotopic iron and sulphur ...
BioAssay record AID 772012 submitted by ChEMBL: Antifungal activity against Candida albicans NRRL Y-477 after 48 hrs by two-fold serial dilution technique.
A multi-point method of determining a time-zero blood volume by the tracer dilution technique. A tracer is injected into the blood stream of a living being, and a plurality of mixed samples of blood and tracer are removed from the blood stream at a corresponding plurality of measured time intervals subsequent to the injecting step. A blood portion volume corresponding to each time interval is automatically determined from the tracer level in the mixed samples, and a time-zero blood portion volume is automatically calculated from the determined blood portion volumes and time intervals.
Gelatin Finings are used to clear beer before kegging or bottling. Gelatin is the most powerful organic fining agent available in brewing.. Note: Gelatin is not vegetarian. If you plan to serve your beer to vegetarian friends, do not use Gelatin finings!. Across the Internet on the various brewing forums there is a massive amount of conflicting opinion on the correct way to use gelatin finings. One of the main things that people get wrong, is they boil the gelatin before adding it to the beer. Boiling gelatin will render it useless; do NOT boil the gelatin finings before adding them to the beer! I hope to clear things up here with a definitive method to using gelatin finings to clear a 5 gallon batch of beer. This is a tried and tested method which I have used for many brews with great success.. ...
Learning Outcomes : At the end of this lesson, a student is able to : i. define radioisotopes ii. name examples of radioisotopes iii. describe applications of radioisotopes [ Click Radioisotopes to download powerpoint show]
The SNMMI Targeted Radioisotope Therapy (TRT) Working Group is very pleased to present their first webinar series on targeted radioisotope therapies for non-nuclear medicine physicians. This webinar series consists of 6 webinars, each focused on a specific disease area. Each webinar offers participants free CME.. ...
TO ANALYSE MATERIALS AND ARTICLES IN CONTACT WITH FOOD USING THE TECHNIQUE OF ISOTOPE DILUTION GC-MS AND TO ANALYSE THE FOOD IN CONTACT WITH THESE MATERIALS TO ASSESS THE MIGRATION OF BENZENE INTO FOOD ...
Use of radioisotopes in dating. To be able to distinguish the relative ages of rocks from such old material, and to get a better time resolution than that available from long-lived isotopes, short-lived isotopes that are no longer present in the rock can be used.
Canine left ventricular wall metabolites (ATP, creatine phosphate, glycogen, glucose, glucose-6-phosphate, and lactate) were assessed in the ischemic region of the wall after 17 minutes of ligation of the left anterior descending coronary artery at its midlevel. Variations in the degree of lactate accumulation were found between different sites in the same ischemic region and between the outer and the inner left ventricular wall at the same site. High levels of lactate were associated with S-T segment elevation in the epicardial electrocardiogram, but no lactate accumulation or only mild lactate accumulation was found at isoelectric sites. Lactate accumulation at isoelectric sites was higher in the outer wall than it was in the inner wall; the opposite tendency was observed at sites of S-T segment elevation. In addition to high lactate levels, sites of S-T segment elevation demonstrated a more pronounced depletion of ATP and creatine phosphate, indicating not only a marked anaerobic glycolysis ...
This graph shows the total number of publications written about "Fluorine Radioisotopes" by people in this website by year, and whether "Fluorine Radioisotopes" was a major or minor topic of these publications ...
View Notes - Ch5AffinityChromatography from S 117 at Indiana. 5-1 Ch. 5 Affinity Chromatography for the Isolation of LDHObjectives Develop pipeting skills and practice dilution techniques Separate
Radionuclides also termed as radioisotopes are elements that possess radioactivity. It means upon decay they emit radiations like alpha, beta or gamma particles and trans..
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Radioisotope dating conveys an aura of reliability both to the general public and professional scientists. But is the method all its cracked up to be?. ...
Farming was deep in my roots on both sides of my family. "Itll be easy", I thought. "You just plant some seeds, and watch them grow." Was I in for a big surprise. No one ever told me about bugs, and pests, and plant diseases. No one ever told me about the weeds, and how weeding will cause you to go gray before your time. Oh, and the animals. Other than a dog, I had never … [Read more...] ...
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TY - JOUR. T1 - Positional isotope exchange analysis of the Mycobacterium smegmatis cysteine ligase (MshC). AU - Williams, La Kenya. AU - Fan, Fan. AU - Blanchard, John S.. AU - Raushel, Frank M.. PY - 2008/4/22. Y1 - 2008/4/22. N2 - MshC catalyzes the ATP-dependent condensation of GlcN-Ins and cysteine to form Cys-GlcN-Ins, which is an intermediate in the biosynthetic pathway of mycothiol, i.e., 1-D-myo-inosityl-2-(N-acetyl-L-cysteinyl)amido-2-deoxy-α- D-glucopyranoside (MSH or AcCys-GlcN-Ins). MSH is produced by Mycobacterium tuberculosis, members of the Actinomycetes family, to maintain an intracellular reducing environment and protect against oxidative and antibiotic induced stress. The biosynthesis of MSH is essential for cell growth, and therefore, the MSH biosynthetic enzymes present potential targets for inhibitor design. The formation of kinetically competent adenylated intermediates was suggested by the observation of positional isotope exchange (PIX) reaction using [βγ-18O6]-ATP in ...
The validity of the indicator dilution method for measuring the capillary diffusion capacity for 51Cr-EDTA in hyperaemic skeletal muscle ...