Physiological and pathological factors influencing bovine alpha-lactalbumin and beta-lactoglobulin concentrations in milk

Bovine alpha-lactalbumin and beta-lactoglobulin concentrations were determined by radial immunodiffusion in 354 milk samples from uninfected and 98 samples from infected quarters from 42 Holstein-Friesian cows taken at 30, 150, and 270 days of lactation. alpha-Lactalbumin and beta-lactoglobulin concentrations were not affected by quarter location. The alpha-lactalbumin decreased at the end of lactation and in samples collected beyond second lactation. The beta-lactoglobulin concentration increased with stage of lactation. There was a positive correlation between alpha-lactalbumin and beta lactoglobulin (r = .12). Milk from uninfected quarters had mean alpha-lactalbumin and beta-lactoglobulin concentrations of 1.47 and 4.6 mg/ml, respectively. Milk from quarters infected by major pathogens or Corynebacterium bovis had less alpha-lactalbumin. Milk from quarters infected by minor pathogens had less beta-lactoglobulin. There was a negative correlation between alpha-lactalbumin concentration and somatic cell count (r = .31), which was amplified by infection status of quarters. No correlation was noted between somatic cell count and beta-lactoglobulin concentration when considered over the whole sampling period, but the correlation became negative in quarters infected by major pathogens.     

Optimizing the design of railway tank cars to minimize accident-caused releases

The design of vehicles transporting hazardous materials has important public safety and economic implications. Conventional wisdom among industry and government has held that a thicker tank on railroad tank cars and trucks reduces risk. However, a thicker tank increases vehicle weight and thus leads to an increase in the number of shipments required to transport the same amount of product and consequently greater exposure to accidents. In this research we develop a model that analyzes the tradeoff between increased damage resistance and greater exposure to accidents in which the objective function is minimization of the probability of release. The model accounts for the reduction in tank car release probability as a function of tank thickness, and the increased exposure to accidents that occurs due to the increased number of shipments needed for the heavier car. Three variables affecting this optimal thickness are considered in this paper: the volumetric capacity of the tank, the probability of release from other, non-tank sources, and the weight capacity of the car. Sensitivity analyses using the model indicate that for any particular configuration of tank car there is an optimal thickness. This optimal thickness is affected by several factors and there is no single optimum for all tank cars.     

Verf?rbung grau und wei? pigmentierter Beschichtungen auf Acrylharzbasis auf Tropenh?lzern

Ohne Zusammenfassung     

Water-soluble copolymers: 22. Copolymers of acrylamide with 2-acrylamido-2-methylpropanedimethylammonium chloride: Aqueous solution properties of a polycation

The viscometric, turbidimetric and potentiometric properties of copolymers of acrylamide (AM) with 2-acrylamido-2-methylpropanedimethylammonium chloride (AMPDAC) were studied in aqueous solutions. The AMPDAC polymers exhibit poor salt tolerance and large, negative viscosity/temperature coefficients. Furthermore, the polymers were found to be sensitive to changes in pH. The AMPDAC polymers undergo phase separation in the presence of dianions as a function of temperature and AMPDAC composition.     

Mutagenicity of three agricultural soils

A chemical and biological testing protocol was employed to evaluate the mutagenic potential of the organic compounds extracted from three agricultural soils. The analytical procedures used included bioassays with Salmonella typhimurium and Aspergillus nidulans for the detection of point mutations and a gas chromatography/mass spectrometry/computer system to identify major organic constituents. The extracts of all three soils exhibited mutagenic response in the bioassays. At a dose level of 1000 micrograms per plate, the organic extract of the Bastrop clay induced 434 net revertants; while at the same dose level the Norwood sandy clay and the Sassafrass sandy loam induced 35 and 178 net revertants, respectively, in the Salmonella assay with metabolic activation. In the Aspergillus assay, the extract of the Norwood and Bastrop soils induced a positive response without metabolic activation; this effect was reduced or eliminated in the presence of metabolic activation. Chemical analysis identified a variety of initiators, promotors, inhibitors, and cocarcinogens; however, there were no mutagenic compounds identified in any of the soil extracts. The results of this combined testing protocol indicate that the agricultural soils tested had an inherent level of mutagenic activity, which was not detected by GC/MS analysis alone, and this activity may be related to the past history of agricultural practices, including biocide applications, fertilization, and cultivation.     

Influence of Hydroxypropyl Methylcellulose and of Manufacturing Technique on in Vitro Performance of Selected Antacids

Factors affecting the performance of antacids F-MA 11, dihydroxy aluminum aminoacetate, magaldrate and magnesium hydroxide were studied in vitro using Schaub's acid neutralization test, a modified Reheis reaction velocity test and the USP test. From the results obtained it was evident that type and combination of antacid, the adjuvants and formulation techniques used in preparation of antacids affect their performance. The USP preliminary antacid test and acid neutralization test are not optimal in vitro tests to evaluate in vitro onset and duration of action of antacids.