Rapid Chemical Method Research Articles

Toxicity enhancement of an aliphatic petrogenic unresolved complex mixture (UCM) by chemical oxidation

The effect of a lubricating oil saturated hydrocarbon feed stock, and its chemical oxidation products, on the feeding rate of mussels ( Mytilus edulis), was investigated. The saturated hydrocarbons had no effect, whilst oxidation resulted in an increase in toxicity. The relatively non-toxic nature of the hydrocarbons was attributed to the low aqueous solubility. Oxidation resulted in the formation of products with a greater solubility, which were sufficiently hydrophobic to be narcotic toxicants. The rapid chemical oxidation method may thus provide a “model” for assessing the toxic potential of unresolved complex mixtures (UCMs) in the environment, since it produces compounds similar to those reported to be formed by natural oxidation in the environment and by oxidation of oils in engines, namely carboxylic acids and ketones

Decay of152Nd

The decay of 11.6 min 152 Nd to levels of odd-odd 152 Pm has been studied with HpGe, Ge(Li) detectors, LEPS, and a plastic scintillation detector by γ-ray singles, time dependent γ-ray singles, γ-γ coincidence and β-γ delayed coincidence measurements. Sources were prepared by a rapid chemical separation method from the fission products of 235 U. Ten γ-rays were observed and five of them are newly observed (19.5, 25.0, 44.4, 545.6 and 570.7 keV). Half-lives of the 16.1 and 28.5 keV transitions were measured to be 2.1±1.0 ns and ≤1.0 ns, respectively. A decay scheme of 152 Nd involving 2 new levels at 25.0 and 570.7 keV in 152 Pm and spin-parities are proposed. The Nilsson configurations of excited states in 152 Pm are discussed.

Analysis and purification of toxic peptides from cyanobacteria by reversed-phase high-performance liquid chromatography

A simple, rapid and reliable chemical analysis method for microcystins (cyanoginosins) has been studied. Three different mobile phases for high-performance liquid chromatography were selected and optimized. Also the adsorptive powers of three commercially available C 18 cartridges were compared and the results successfully applied to the clean up of three of the toxins. Finally a total system for the analysis and isolation of microcystins was established.

A chemical method for the deglycosylation of proteins

A simple and rapid chemical method for the deglycosylation of glycoproteins has been developed. The method involves the incubation of protein with trifluoromethanesulfonic acid at 0 °C from 0.5 to 2 h followed by the neutralization of the acid with aqueous pyridine at −20 °C. The method has been applied effectively to fetuin, ovine submaxillary mucin, ovine lutropin, and human choriogonadotropin. In 1 h almost all of N- and O-linked carbohydrates from ovine lutropin and human choriogonadotropin, with the exception of the linkage N-acetylglucomsamine or N-acetylgalactosamine, were removed. Similarly, in 1 h all N-linked carbohydrates, excepting again the linkage sugar, in fetuin were degraded. Longer reaction times up to 2 h completely removed the O-linked carbohydrate chains from fetuin and ovine submaxillary mucin. The deglycosylated hormones thus prepared retained their immunological and biological activities.

A rapid and efficient physiologic chemical method of labeling plasma proteins with indium-111

A rapid physiologic chemical method had been developed for labeling plasma proteins with 111In. Human serum albumin, IgG, fibrinogen, transferrin, lactoferrin and the enzyme bovine thrombin had been successfully labeled with exceptionally high labeling yields of greater than 98%. In vitro bioassays confirmed that 111In-fibrinogen and 111In-thrombin retained 96–99% of their biochemical activities after labeling with the radionuclide. All radiolabeled proteins were stable at 2–8°C in excess of 3 week periods without elution of the “label” or any significant loss of biological activity.

Determination of cell wall teichoic acid structure of staphylococci by rapid chemical and serological screening methods

Investigations of cell wall teichoic acid structures of various staphylococci were carried out by a rapid method based on the gas-liquid chromatographic separation of products obtained after treatment of phenol-extracted cells with 70% hydrofluoric acid. In most of the strains teichoic acids of the poly(glycerolphosphate) and/or poly(ribitol-phosphate) type were found. Teichoic acids of the poly(glycerolphosphate-N-acetylglucosaminephosphate) type and polymers consisting of N-acetylglucosaminephosphate were present in few strains. The results obtained by the rapid chemical screening method were compared with data obtained by serological analysis of teichoic acid structures using specific antisera and the lectin wheat germ agglutinin. Teichoic acid components occurring in low concentrations could only be detected with the chemical and not with the serological method. A number of strains of species of the genus Staphylococcus have been studied using these rapid methods. With a few exceptions, the teichoic acid structure proved to be a constant marker within a given species.

An evaluation of the phylogenetic position of the dinoflagellate Crypthecodinium cohnii based on 5S rRNA characterization.

Partial nucleotide sequences for the 5S and 5.8S rRNAs from the dinoflagellate Crypthecodinium cohnii have been determined, using a rapid chemical sequencing method, for the purpose of studying dinoflagellate phylogeny. The 5S RNA sequence shows the most homology (75%) with the 5S sequences of higher animals and the least homology (less than 60%) with prokaryotic sequences. In addition, it lacks certain residues which are highly conserved in prokaryotic molecules but are generally missing in eukaryotes. These findings suggest a distant relationship between dinoflagellates and the prokaryotes. Using two different sequence alignments and several different methods for selecting an optimum phylogenetic tree for selecting an optimum phylogenetic tree for a collection of 5S sequences including higher plants and animals, fungi, and bacteria in addition to the C. cohnii sequence, the dinoflagellate lineage was joined to the tree at the point of the plant-animal divergence well above the branching point of the fungi. This result is of interest because it implies that the well-documented absence in dinoflagellates of histones and the typical nucleosomal subunit structure of eukaryotic chromatin is the result of secondary loss, and not an indication of an extremely primitive state, as was previously suggested. Computer simulations of 5S RNA evolution have been carried out in order to demonstrate that the above-mentioned phylogenetic placement is not likely to be the result of random sequence convergence. We have also constructed a phylogeny for 5.8S RNA sequences in which plants, animals, fungi and the dinoflagellates are again represented. While the order of branching on this tree is the same as in the 5S tree for the organisms represented, because it lacks prokaryotes, the 5.8S tree cannot be considered a strong independent confirmation of the 5S result. Moreover, 5.8S RNA appears to have experienced very different rates of evolution in different lineages indicating that it may not be the best indicator of evolutionary relationships. We have also considered the existing biological data regarding dinoflagellate evolution in relation to our molecular phylogenetic evidence.

Production of Carrier-free 38K by means of photonuclear reactions

The simultaneous 40 Ca(γ, pn) 38 K and the 40 Ca(γ, 2n) 38 Ca ⇀ 38 K reactions have proved to be useful for the production of carrier-free 38K. The production rates of 38K and contaminant were determined as a function of the maximum bremsstrahlung energies between 30 and 60 MeV. As a result, the production rate of 38K at an electron energy of 60 MeV was found to be 840 μCi μAh −1 g −1 of Ca. In addition, the rapid chemical separation method of carrier-free 38K was studied in detail by using 43K and 47Ca tracers. Carrier-free 38K for medical uses was separated with a 70% yield within 8 min of the end of irradiation.

Rapid Chemical Confirmation Method for Aflatoxins B1 and G1 by Direct Acetylation on a Thin Layer Plate Before Chromatography

Abstract A method of acetylation of aflatoxins Bx and G1 before thin layer chromatographic (TLC) identification is described. Extracts containing anatoxin B1 and/or G1 are spotted on a silica gel TLC plate and overspotted with acetic anhydride and HCL. After reaction, the plate is developed and the Rf values of reacted anatoxin B1 and/or G1 are compared with those of authentic standards treated similarly.

A rapid chemical method of labeling human plasma proteins with 99 mTc-pertechnetate at pH 7.4

A successful method for labeling human plasma proteins with 99 m Tc-pertechnetate by chemical means is described. The labeling methodology involves the production of 99 m Tc-(Sn)citrate complex species with high protein binding capacity at pH 7.4 condition following initial chemical reduction of sodium 99 m Tc-pertechnetate by stannous chloride. A combined labeling efficiency range of 95–99% for 99 m Tc-labeled fibrinogen, immune gamma globulin and serum albumin is achieved. The actual amount of labeled protein content in the product is found to be 85–95% when assayed by ITLC and 74–85% by TCAA protein precipitation. In vitro experimental data indicate that 99 m Tc-fibrinogen contains an average of 85% clottable protein with an average clottability of 95%. This strongly suggests that the radioactive proteins retain much of their biological and physiological activities after the labeling process.

Introductory class exercises in experimental embryology usingXenopus laevis

Abstract This paper describes classical experiments of experimental embryology which may be repeated at class level using the early embryos of Xenopus laevis. The experiments demonstrate the effects of lithium on the early development of the nervous system, and the use of hypertonic salt solutions to produce exogastrulation. Both experiments involve the removal of the jelly coats around the embryo, and for this purpose a rapid chemical method using a cysteine hydrochloride/papain solution is described. Both experiments are theoretically important: the effects of lithium are used as evidence for the existence of an anterior-posterior gradient in the early embryo, while exogastrulation provides a convenient system for interfering with the primary inductive effect of the chordo-mesoderm, necessary for ectodermal neuralization. The procedure for obtaining fertile eggs from mature Xenopus specimens by injection of mammalian chorionic gonadotrophin is described.

Estudo de processo químico para determinação do valor calórico, em plantas forrageiras

The authors tried to study a rapid and precise chemical method for determining the caloric value in pasture plants this method showld be less onerous and substitute the traditional method (calorimetric pump) which takes too much time because in it is impossible to work many samples simultaneously. The alterations suggest are largely applied to determine the caloric value in forage plants and the reduction of volumes employed brings a low price of determination without prejudice in the exactness of the results.

Chemical etching and fabrication of ridge waveguides on Bi12GeO20 single crystals

Chemical etching of Bi12GeO20 was investigated, and the developed technology was applied to the fabrication of ridge waveguides by an easy and rapid chemical etching method. The etching solution was prepared by mixing concentrated HCl, concentrated H2O2, and 5M NH4Cl. Ridge waveguides (0.3 mm to a few microns in size) prepared on the (110) surface had a trapezoidal cross section, and for a higher volume ratio of HCl and a longer etching time the cross section was triangular. Rectangular ridge guides were also prepared on the (100) surface, but this application is limited to small-size (several microns) ridges because with deep etching the surface is covered with etch pits and becomes rough.

Reactions of Coordinated Molecules : I. The oxidation of transition metal carbenoid complexes by iodosobenzene; a comparative study

The reaction of transition metal carbenoid complexes with oxidizing agents results in the oxidation of the carbenoid ligand forming the corresponding carboxylic acid derivative. A study of this reaction using pyridine- N-oxide, ceric ammonium nitrate and iodosobenzene as the oxidants reveals that the yield of the carboxylic acid derivative is affected significantly by the solvent medium. Oxidations using pyridine- N-oxide in tetrahydrofuran solution generally afford the organic acid derivatives in good to excellent yields. Iodosobenzene is a selective oxidant affording the greatest yield of ethylene carbonate and it is the first oxidant reported to oxidize an amino-carbenoid complex to the corresponding amide. This oxidation reaction represents a convenient and rapid chemical method for the characterization of carbenoid complexes.

Spectrofluorometric Determination of Lasalocid Sodium in Finished Feeds and Premixes

Abstract A simple, rapid, and sensitive chemical method is described for determining lasalocid sodium in finished poultry feeds and premixes. The drug is extracted with ethyl acetate directly from premixes and after a brief treatment with pH 4.7 buffer from finished feeds. Lasalocid sodium concentration is measured spectrofluorometrically and a correction for nonspecific fluorescence is determined after formation of a lasalocid- boric acid complex. Replicate assays of typical poultry mashes and pellets containing about 0.0075% lasalocid sodium yielded coefficients of variation of 2.8 to 5.0%. Average recovery of lasalocid sodium added in the laboratory at 0.0037, 0.0075, and 0.0112% was 90% with a pooled standard deviation of ±1.86%.

Chemical Determination of Component Ratio and Potency of Gentamicin Complex

A rapid chemical method for estimating the total gentamicin potency as well as for quantitating the individual components in one step by direct densitometry after resolution on TLC is described. Because the amount of each component is read directly from the plate after separation of impurities and the values are interpolated from standards treated in an identical manner, this method is more accurate for estimating total potency than the official microbiological assay in which biologically active impurities may interfere.

Chlorophyll Analysis as a Method of Evaluating the Standing Crop Phytoplankton and Primary Productivity

of plant production and the standing crop in the aquatic environment (Goldman, 1965). The measurement of plant pigments, especially chlorophyll a, is the only current rapid chemical method available to estimate the amount of living particulate plant matter. Attention in this paper will be given mainly to analytical methods of chlorophyll analysis, field sampling, chlorophyll-standing crop estimates, and interpretation of the relationship of photosynthesis to chlorophyll.

Rapid chemical method for determining sulfur in glass

Rapid chemical method for determining sulfur in glass

Gonadotropin Therapy

The individual patient response to menotropins therapy was found to be extremely variable. Failure to appreciate this variability can lead to ovarian overstimulation. Overstimulation was found to be associated with abnormally high excretion levels of total estrogen. The author concluded that daily monitoring of estrogen excretion by a rapid chemical method was necessary to determine the optimum time for the administration of chorionic gonadotropin and, at the present time, provided the best method for preventing ovarian overstimulation.

Determination of Lead in Gasoline by X-Ray Fluorescence Using an Internal Intensity Reference

The determination of lead additive in blended gasoline is one of several process control tests which is routinely required to determine that the finished product meets the specification which has been set up for the particular fuel. Chemical procedures traditionally have been used as methods of test for determining the lead content of blended gasolines. Such tests inherently require a significant amount of effort and time. Furthermore, if a more rapid shortcut chemical method is applied, it may prove unsuccessful for recovering and measuring total lead where the lead occurs in combination with certain alkyl radicals. An instrumental method in which lead is determined by its x-ray fluorescence property is independent of the type of alkyl combination. It also has advantages in speed and simplicity over a chemical method since the analysis is made directly on the gasoline sample with no preliminary separation steps being required.