Search results for "dilution"

On the applicability of density dependent effective interactions in cluster-forming systems

2016

We systematically studied the validity and transferability of effective, coarse-grained, pair potentials in ultrasoft colloidal systems. We focused on amphiphilic dendrimers, macromolecules which can aggregate into clusters of overlapping particles to minimize the contact area with the surrounding (implicit) solvent. Simulations were performed for both the monomeric and coarse-grained model in the liquid phase at densities ranging from infinite dilution up to values close to the freezing point. For every state point, each macromolecule was mapped onto a single interaction site and the effective pair potential was computed using a coarse-graining technique based on force-matching. We found e…

Iodine determination in food samples using inductively coupled plasma isotope dilution mass spectrometry.

1998

Two different sample treatment methods are used in connection with inductively coupled plasma isotope dilution mass spectrometry for accurate and precise determinations of iodine traces in food samples. 129I-enriched iodate is applied as a spike compound for the isotope dilution step. Extraction of iodine by tetramethylammonium hydroxide (TMAH) solution at high temperatures in a closed vessel is one of the sample treatment methods. The other one is a complete decomposition of the sample with a mixture of perchloric acid and nitric acid using microwave assistance. By analyzing different certified reference materials (three milk powders with different iodine levels, BCR CRM 63, 150, and 151; …

Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinatio…

2000

An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes 194Pt, 108Pd, 99Ru, and 191Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng x g(-1), 0.075 ng x g(-1), and 0.015 ng x g(-1) were achieved for Pt,…

The Influence of Diffusion of Inert Gases on the Determination of Blood Flow by the Clearance Method

1968

Critical evaluation of two commonly used techniques for the treatment of data from extract dilution sniffing analysis

1993

The data from the extract dilution sniffing analysis of beer samples have been treated by two methods of analysis to give either «charm» or «FD» values. The results obtained from these two methods were compared and demonstrated that the rank order of intensity of the odor-active regions was different for most panelists when the data were presented as charm rather than FD values. Points of uncertainty observed while using this method such as between- and within-individual reproducibility and gaps in the coincident response five also been discussed

SALMO and S3M: A Saliva Model and a Single Saliva Salt Model for Equilibrium Studies.

2014

A model of synthetic saliva (SALMO, SALiva MOdel) is proposed for its use as standard medium inin vitroequilibrium and speciation studies of real saliva. The concentrations come out from the literature analysis of the composition of both real saliva and synthetic saliva. The chief interactions of main inorganic components of saliva, as well as urea and amino acids, are taken into account on the basis of a complex formation model, which also considers the dependence of the stability constants of these species on ionic strength and temperature. These last features allow the modelling of the speciation of saliva in different physiological conditions deriving from processes like dilution, pH, a…

A microplate version of the SOS/umu-test for rapid detection of genotoxins and genotoxic potentials of environmental samples

1991

Abstract The umu-microtest is a miniaturized automated short-term test version proposed for screening of umuC-dependent mutagenic potentials of chemicals relevant to environmental pollution, river water and industrial waste water. The test is based on the SOS/umu-test and has been modified in order to allow extensive testing of environmental samples. Genetically engineered Salmonella typhimurium (TA1535/pSK1002) are incubated on a microplate rotor in a sloping position for 2 h with the test samples, followed by addition of fresh culture medium to reach a 10-fold dilution of the incubation medium. 2 h later, the activity of the β-galactosidase, which reflects umuC induction, is determined co…

Dissection of C1q Capability of Interacting with IgG

1997

Abstract C1q-bearing immune complexes have been observed in diseases such as rheumatoid arthritis and human immunodeficiency virus infection-associated neuropathy. For the purpose of understanding better the phenomenon of C1q-bearing immune complexes, we investigated the constancy of the C1q-IgG interaction. An enzyme-linked immunosorbent assay was developed in which wells were coated with IgG to mimic antigen-complexed IgG. Serial dilutions of C1q were applied for distinct time intervals, and bound C1q was detected either directly or after exposure to one of several elution buffers. Our results show that a part of C1q attached to IgG forms a tight association that is not reversible under t…

Simultaneous detection of the seven main tomato-infecting RNA viruses by two multiplex reverse transcription polymerase chain reactions

2012

Cucumber mosaic virus, Tomato spotted wilt virus, Tomato mosaic virus, Tomato chlorosis virus, Pepino mosaic virus, Torrado tomato virus and Tomato infectious chlorosis virus cause serious damage and significant economic losses in tomato crops worldwide. The early detection of these pathogens is essential for preventing the viruses from spreading and improving their control. In this study, a procedure based on two multiplex RT-PCRs was developed for the sensitive and reliable detection of these seven viruses. Serial dilutions of positive controls were analysed by this methodology, and the results were compared with those obtained by ELISA and singleplex versions of RT-PCR. The multiplex and…

Horizontal and vertical food web structure drives trace element trophic transfer in Terra Nova Bay, Antarctica

2019

Abstract Despite a vast amount of literature has focused on trace element (TE) contamination in Antarctica during the last decades, the assessment of the main pathways driving TE transfer to the biota is still an overlooked issue. This limits the ability to predict how variations in sea-ice dynamics and productivity due to climate change will affect TE allocation in the food web. Here, food web structure of Tethys Bay (Terra Nova Bay, Ross Sea, Antarctica) was first characterised by analysing carbon and nitrogen stable isotopes (δ13C, δ15N) in organic matter sources (sediment and planktonic, benthic and sympagic primary producers) and consumers (zooplankton, benthic invertebrates, fish and …