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At least 55 records · Page 3Linked to original sources
PubMed2000

Centrifugal precipitation chromatography: principle, apparatus, and optimization of key parameters for protein fractionation by ammonium sulfate precipitation.

A novel chromatographic system introduced here internally generates a concentration gradient of ammonium sulfate (AS) through a long separation channel under a centrifugal force field. Protein samples are exposed to a gradually increasing AS concentration and precipitated along the channel. Then, chromatographic elution is initiated by gradually decreasing the AS concentration in the gradient which causes the proteins to repeat dissolution and precipitation through the channel. Consequently, they are eluted out in the order of their solubility in the AS solution. The separation column consists of a pair of disks equipped with mutually mirror-imaged spiral grooves. A dialysis membrane is sandwiched between the disks to form two identical channels partitioned by the membrane. The disk assembly is mounted on the sealless continuous-flow centrifuge. When a concentrated AS solution is eluted through one channel and water through the other channel in an opposite direction, an exponential AS gradient is formed through the water channel. A series of basic experiments was performed to study the rates of AS transfer and osmosis through the membrane, and the operational parameters including elution time, revolution speed, inclination of gradient, and sample size were optimized using stable protein samples. Preliminary applications were successful in purification of monoclonal antibody from cell culture supernatant and an affinity separation of recombinant ketosteroid isomerase from a crude Escherichia coli lysate.

Ammonium Sulfate↗
PubMed2005

Precipitation of hydroxyapatite nanoparticles: effects of precipitation method on electrophoretic deposition.

Electrophoretic deposition is a low-cost, simple, and flexible coating method for producing hydroxyapatite (HA) coatings on metal implants with a broad range of thicknesses, from < 1 microm to > 500 microm. As for many other HA coating techniques, densification of electrophoretically deposited coatings involves heating the coated metal to temperatures above 1000 degrees C. Metal substrates tend to react with HA coatings at such temperatures inducing decomposition at temperatures below 1050 degrees C (decomposition for pure HA normally occurs above 1300 degrees C). Therefore, densification of these coatings needs to be conducted at temperatures lower than 1050 degrees C, and this necessitates the use of high-surface-area HA nano-precipitates, rather than commercially available pre-calcined powders, which densify at temperatures typically higher than 1200 degrees C. HA nano-precipitates were prepared by three methods and deposited on metal substrates by electrophoresis: (1) the acid base method, which produced plate-like nano-particles with a 2.5:1 aspect ratio, and severely cracked coatings; (2) the calcium acetate method, which produced needle-like nano-particles with a 10:1 aspect ratio, and slightly cracked coatings; (3) the metathesis method, which produced rounded nano-particles with a 2:1 aspect ratio, and high-quality crack-free coatings. The results suggested that the less equiaxed the nano-particles, the more cracked the coatings obtained by the electrophoretic deposition technique.

Acetates↗
PubMed1989

Purification of IgG from serum with caprylic acid and ammonium sulphate precipitation is not superior to ammonium sulphate precipitation alone.

Immunoglobulin G (IgG) from bovine serum raised against Aeromonas Salmonicida was purified by ammonium sulphate precipitation (ASP) or caprylic acid treatment followed by ammonium sulphate precipitation (CAAS). Purity of IgG samples prepared by both methods were examined by High Performance Gel Permeation Chromatography, electrophoresis and antibody activity assay. Results suggest that IgG prepared by ASP is better than that obtained by CAAS method in terms of the yield of the IgG monomers and the recovery of the antibody activity.

Aeromonas↗
PubMed1997

Methanol-precipitated, detergent-treated Newcastle disease virus as an agar-gel precipitation test antigen.

Methanol-precipitated, detergent-treated (Triton X-100) Newcastle disease virus (NDV) was found suitable as an agar gel precipitation test (AGPT) antigen. One hundred and twenty sera were tested by the haemagglutination-inhibition (HI) test and AGPT against NDV. There was a very significant increase in the proportion of AGPT positive samples with increase in HI titre. Hence AGPT can be recommended as a field based test for seromonitoring following vaccinations against ND where laboratory facilities are inadequate.

Agar↗
PubMed2005

Preparation and characterization of uniform nanosized cephradine by combination of reactive precipitation and liquid anti-solvent precipitation under high gravity environment.

In this work, a novel direct method, which was combined with reactive precipitation and liquid anti-solvent precipitation under high gravity environment, had been developed to prepare nanosized cephradine with narrow particle size distribution. Compared with commercial crude cephradine, the prepared cephradine showed a significant decrease in particle size, a significant increase in the specific surface area and shorter dissolving time when used for injection. The characteristic particle size was between 200-400 nm. The specific surface area increased from 2.95 to 10.87 m2/g after micronization. When the amount of L-arginin decreased from 0.25 to 0.18 g, the mixture of nanosized cephradine and L-arginine could still dissolve in 1 min. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the physical characteristics and molecular states remained unchanged after the recrystallization process. This method had potential application in industrial fields because of its low cost, efficient processing and the ease of scaling-up.

Cephalosporins↗
PubMed2001

A statistical assessment of changes in precipitation chemistry at CAPMoN sites, Canada. Canadian Air and Precipitation Monitoring Network.

The objective of this study is to decide if chemical concentrations measured during 1988-1997 in precipitation by the Canadian Air and Precipitation Monitoring Network (CAPMoN) indicate changes in the annual patterns. The inference is based on SO4, NO3, Cl, NH4, Na, Ca and K concentrations monitored daily with the rain water acidity pH. By pattern is understood the probability distribution of the annual sample at a particular location. Most of the annual data can be well described by means of a linear regression model with second order polynomial trend and autocorrelated noise. Statistical analysis based on the model shows luck of systematic significant year to year increases or declines of the concentrations.

Air Pollutants↗
PubMed1996

Composition of the intra-erythroblastic precipitates in thalassaemia and congenital dyserythropoietic anaemia (CDA): identification of a new type of CDA with intra-erythroblastic precipitates not reacting with monoclonal antibodies to alpha- and beta-globin chains.

Ultrathin sections of bone marrow cells from two patients with homozygous beta-thalassaemia, two patients with haemoglobin H (HbH) disease, a patient with congenital dyserythropoietic anaemia (CDA) type III and two patients with severe congenital dyserythropoietic anaemia of an unusual type were reacted with mouse monoclonal antibodies against various globin chains and the reaction visualized using a gold-labelled goat antibody against mouse IgG. The multiple rounded intra-erythroblastic inclusions found in homozygous beta-thalassaemia reacted with the monoclonal antibody against alpha-globin chains but not beta-globin chains, thus confirming that they consisted of precipitated alpha-globin chains. The branching intra-erythroblastic inclusions found in HbH disease and CDA type III reacted with the monoclonal antibody against beta-globin chains but not alpha-globin chains, indicating that they consisted of precipitated beta-globin chains. The two patients with severe CDA had been transfusion-dependent since infancy, had a normal alpha:beta globin chain synthesis ratio or parents with normal red cell indices, displayed prominent dysplastic changes in their erythroblasts, and had intra-erythroblastic inclusions resembling those seen in homozygous beta-thalassaemia. However, unlike those in beta-thalassaemia, the inclusions in these two patients did not react with the monoclonal antibody against either alpha- or beta-globin chains. The inclusions reacted with antibody against zeta-globin chains, but detailed studies in one of the patients indicated that the antigen involved was not zeta-globin. These patients have features not reported in the condition known as dominantly inherited inclusion body beta-thalassaemia and appear to suffer from a novel type of CDA in which the intra-erythroblastic inclusions may consist of some non-globin protein or structurally-abnormal alpha-globin chains.

Anemia, Dyserythropoietic, Congenital↗
PubMed1982

Chronic paroxysmal hemicrania. VI. Precipitation of attacks. Further studies on the precipitation mechanism.

In four of the approximately 40 cases of chronic paroxysmal hemicrania (CPH) that are known so far, attacks that are similar to the spontaneous ones may be precipitated by head movements or pressure against certain points in the neck. Head flexion was used as the precipitation procedure in a 34-year-old female who was studied several times in the course of five years. Attacks occur within 5-40 sec, and the pain is preceded by tearing and conjunctival injection. External rubbing or external compression of the common and internal carotid arteries on the symptomatic side did not produce attacks. The combination of head flexion and external compression of the common or internal carotid arteries on the symptomatic side invariably produced an attack of usual severity and within the usual time. This investigation would seem to render unlikely the possibility of a primary vascular mediation of the signal from the neck to the ocular region. Sympathetic fibres are the likely mediators of the impulses from the neck to the ocular area.

Adult↗
PubMed1976

[Precipitation reaction and hemagglutination-hemolysis reaction in tuberculosis. I. Precipitation reaction (author's transl)].

Sera of patients, blood donors and cattle sera were examined by means of diffusion--in--gel technique using self produced antigens, prepared from H 37 Ra, one fresh isolated strain of M. tbc and BCG Jena. 38.2% of 421 patients with pulmonary tuberculosis reacted positive. Positive reactions were observed in 55.7% of 199 patients suffering from another infectious disease and in 31;7% of normal sera. Most precipitation lines were found with the antigen prepared from H37 Ra after incubation for 7 months. In human sera as well as in cattle a dependence of reactions upon mode of antigen production was evident.

Animals↗
PubMed1978

The comparison of viral antibody titers of acid-precipitated and non-precipitated mouse ascitic fluids.

Mouse immune ascitic fluid has become a primary source of antibody for diagnostic, reference, and research work in many virus laboratories. The inherent disadvantage of ascitic fluid is that it repeatedly forms clots and subsequently loses volume. The acid-precipitation method of Chiewsilp and McCown eliminates the clot formation and does not appreciably alter the antibody titers for several arboviruses, varicella, rabies and influenza viruses.

Acids↗