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PubMed2006

Effect of seeding materials and mixing strength on struvite precipitation.

Struvite precipitation has increasing interest as a technology for removing and recovering phosphorus from wastewater streams. Many chemical factors have been studied, such as optimum pH values and component-ion molar ratios, yet, understanding of physical aspects is lacking. Two physical parameters were tested: (1) seeding material addition and (2) mixing. Objectives were to evaluate three seeding materials and to optimize mixing conditions for struvite-crystal precipitation, growth, and subsequent sedimentation. Results confirm that mixing strength and proper seeding materials increase crystal size and improve settleability. For unseeded solutions, optimum phosphorus removal was achieved at a mixing strength of G = 76 s(-1). Struvite crystals that were added as the seeding material provided the best performance with respect to phosphorus removal and crystal-size distribution. Overall, this study provided information to improve the practical application of struvite precipitation as a phosphorous-treatment technology for wastewaters, while generating a marketable slow-release fertilizer as a product.

Animals↗
PubMed1988

Sensitive assay for thyroglobulin autoantibodies in serum employing polyethylene glycol for precipitation.

A sensitive assay for thyroglobulin autoantibodies (Tg-ab) is described. The assay is based on prolonged incubation of [125I]Tg with serum followed by precipitation of antibody bound [125I]Tg by polyethylene glycol (PEG). The PEG concentration was chosen to give a low precipitation of free [125I]Tg while effectively precipitating Tg-ab-bound [125I]Tg. The lowest reference employed contained 19.5 MRC U/l Tg-ab. This was always different from an incubate without Tg-ab. Tg standard added to samples interfered in the assay giving spuriously low Tg-ab values as in other Tg-ab assays. Tg-ab added to samples was recovered quantitatively. The interassay coefficient of variation was 19.8% and the intra-assay coefficient of variation 11.3%. Only eight of 66 serum samples with various amounts of Tg-ab, measured with the new assay, had levels of Tg-ab detectable by the passive haemagglutination test.

Autoantibodies↗
PubMed1993

Total protein in common duct bile measured by acetonitrile precipitation and a micro bicinchoninic acid (BCA) method.

Bile protein assays are complicated due to interference by other bile substances. In the present study we describe a microtiter plate method for the purification and quantification of bile proteins. The method is based on addition of acetonitrile in three steps to reconstituted freeze-dried bile, followed by ethanol washing of the precipitated proteins. Finally, protein in the precipitate is quantitated by two-point colour development using micro BCA reagents. Overall recoveries of protein in reconstituted bile spiked with exogenous protein (Seronorm) ranged from 91.0% (coefficient of variation; CV = 7.0%) to 97.1% (CV = 2.4%) by recoveries of 125I-Fibrinogen and 125I-Albumin. Bile pigments were largely removed during precipitation and washing, as verified by high pressure liquid chromatography (HPLC). Preferably the samples should be freeze-dried initially, as this lowered the blank readings. Two-point colour development with the BCA reagents were identical for standards assayed directly and standards added to protein depleted bile, and processed through all steps. Hence, no interference by either residual bile constituents nor the reagents upon the BCA protein assay could be detected. Standard curves ranged from 0.05 to 5.0 gl-1 (r > 0.98). Within day reproducibility (n = 15) was 7.8% (CV) and day to day (n = 10) was 12.1% (CV). Mean protein concentration in common duct bile from 30 patients was 1.20 gl-1 (range 0.34-3.87 gl-1). The method appears suitable for assay of bile protein, requires only limited sample volumes and allows processing of many samples within a short time.

Acetonitriles↗
PubMed1993

A high sensitivity dot-blot assay for proteoglycans by cuprolinic blue precipitation.

A highly sensitive blot-assay was developed for glycosaminoglycans (GAGs) and proteoglycans (PGs) utilizing a precipitation reaction by a cationic dye Cuprolinic Blue. The precipitates were deposited into 1-2 mm2 spots on nitrocellulose membrane by using a 96-well filtration apparatus. The dried sheet was digitized by a flat bed scanner and the intensity of the dots was quantitated by an image analysis software. The working range for chondroitin sulfate was 10-300 ng. The response of various GAGs differed according to the number of anionic groups, both sulphate and carboxyl groups being able to bind the dye. The sensitivity of the assay was decreased by high concentrations of GuC, CsC and protein, but not by nonionic detergents, common buffers and 8 M urea. Contact exposure to autoradiography film enabled quantitation of 25-250 DPM, and 1-10 DPM, of 35SO4-radioactivity in precipitated PGs after overnight and 14 days' exposures, respectively.

Animals↗
PubMed1982

Affinity diffusion. I. Method for measuring dissociation constants of precipitating antibodies.

Dissociation constant (Kd) of antigen-antibody reactions can be obtained from the rates (measured by the progression of the precipitate vs. time) with which antigens diffuse into antibody-containing gels, as a function of antibody-concentration. A bovine serum albumin vs. rabbit anti-bovine serum albumin system was studied with whole antiserum and with its purified IgG fraction. A value was found for Kd of approximately 1.0 x 10-5 moles per liter. It is note- worthy that in monodimensional single diffusion gel precipitation systems of this type, the rate of progression of the precipitate front is significantly faster than the molecular diffusion coefficient of the antigen.

Antibody Affinity↗
PubMed1978

Methods for removing uranyl acetate precipitate from ultrathin sections.

Precipitate resulting from en bloc staining with uranyl acetate was removed by treating sections with 15% oxalic acid in 50% methanol for 30 minutes at 40 C. Precipitate resulting from poststaining sections with hot uranyl acetate was removed by rinsing sections in 0.25-0.50% aqueous oxalic acid for 10-15 seconds at room temperature. Rinsing sections for longer than 30 seconds removed uranyl precipitate and also destained the sections. These procedures did not damage the embedding medium or cellular detail.

Aedes↗
PubMed1999

Precipitation of calcium oxalate monohydrate at phospholipid monolayers.

Studies of calcium oxalate monohydrate (COM) precipitation at Langmuir monolayers of the phospholipids dipalmitoylphosphatidylglycerol (DPPG), dipalmitoylphosphatidylcholine (DPPC), and dipalmitoylphosphatidylserine (DPPS) are reported. The precipitation is heterogeneous and selective, with a majority of crystals orienting with the COM (101) face toward the monolayer interface for each phospholipid. The number density of COM crystals depends on the identity of the phospholipid monolayer, decreasing in the order DPPG > DPPS > DPPC. It was also found that COM precipitation increases as the surface pressure of the monolayer is lowered and with the addition of low levels (<0.1%) of cholesterol. The possibility that changes in monolayer fluidity influence COM attachment is discussed.

Calcium Oxalate↗
PubMed1976

Precipitation hardening in gold-cobalt alloys.

The precipitation hardening in gold-cobalt alloys containing less than 5 wt.%Co was studied by means of resistivity, hardness, X-ray diffraction, and optical microscopic examination. The hardness curves showed two hardness peaks after isothermal ageing below the temperature of 250 or 300 degrees C. It was considered that the first peak was due to the formation of G.P. zone which was confirmed by reversion phenomenon. The second peak was due to the growth of metastable cobalt-rich precipitate, and this stage was found to make a major contribution to the age-hardening in the present alloys. The nodular products at grain boundary do not play an important role in age-hardening. Acitvation energies, order of the reaction involved, and the rate constant for the growth process were established. The difference in growth mechanism of the metastable precipitate was deduced from the kinetics data.

Chemical Precipitation↗
PubMed1998

[Isotope tracer combined with trichloroacetic acid precipitation method for determination of nerve growth factor concentration in mouse plasma].

OBJECTIVE: To establish the radioisotope (125I) tracer method combined with trichloroacetic acid (TCA) precipitation for the determination of nerve growth factor (NGF) in mouse plasma. METHODS: Radioisotope tracer labelling method combined with TCA precipitation was used to determine NGF in mouse plasma. RESULTS: The detection limit of the method for NGF in plasma was 2.0 ng/ml. The intra-assay cv (CV) and the inter-assay CV were all less than 10%. The assay linearity was determined over the range of 12.5-400 ng/ml in plasma and the correlation coefficient was 0.9990. The average recovery of the method for NGF was 95.21%. CONCLUSIONS: The radioisotope tracer method combined with TCA precipitation is stable, sensitive and reliable. It is suitable for the determination of NGF concentration in mouse plasma.

Animals↗
PubMedDate not supplied

Contrast medium precipitation in the stomach between contiguous plain and contrast CT scans.

Precipitation of diluted Gastrografin (meglumine sodium amidotrizoate) occurred in the stomach during computed tomography (CT) examination in a 43-year-old man with fasting. Precipitation was not observed on the initial plain CT scan, but was demonstrated on the contrast-enhanced CT scan following the plain CT. Hyperacidity in the stomach might be promoted during CT examination and cause precipitation between scans.

Adult↗
PubMed2000

[Impact of precipitation and underground water level in the edge of oases on growth and decline of Nitraria tangugtorum community].

Based on the data from underground water monitoring, meterological measuring and fixed sample square investigating in successive years at the edge of the oasis in Minqin, Gansu, the impact of precipitation and underground water on the growth and decline of Nitraria tangutorum community was studied. The result showed that the desiccated environment in oases driven by the decline of underground water level was favorable for the growth and develoment of N. tangutorum community, and made this species more xerophilous. This declining underground water level was not a limiting factor for N. tangutorum growth in late years. These N. tangutorum-dominated communities were predicted to survive comparatively longer, and to function as sand fixer and wind breaker at oasis edge in Minqin. When average annual precipitation was about 110 mm, N. tangutorum would maintain its normal growth, but the community couldn't spread freely. Only when the annual precipitation was up 140 mm in two years running, could its growth be improved.

Chemical Precipitation↗
PubMed2002

Precipitating factors for diabetic ketoacidosis.

OBJECTIVE: The aim of this study is to identify the precipitating factors from a medical and social point of view, in addition to discussing some clinical and laboratory aspects of diabetic ketoacidosis. METHODS: Sixty-eight patients were admitted to King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia, over a 2 year period, (April 1999 through to April 2001). Diagnosis of diabetic ketoacidosis was based on: clinical features, serum sugar >12 mmol/L with ketonuria, bicarbonate and base deficit. RESULTS: The mean age was 22.5 years (0.5-87) years with a male to female ratio of 1.4:1. Poor compliance to continue the treatment and infection were the most common precipitating factors being responsible for 54.4% and 28% cases. A low mortality rate of 2.9% in our study compared favorably with other studies, which contributed to a high level of medical care in King Abdulaziz University Hospital. CONCLUSION: Diabetic ketoacidosis is a fatal complication among our diabetic patients. Implementing a patient education program to increase awareness of the disease is the most important step in the prevention of this complication. The authorities should ensure availability of insulin to all patients, either free or at lower prices. The role of cultured and socioeconomic factors in aggravating or precipitating diabetic ketoacidosis should always be considered and where possible, eliminated

Adolescent↗
PubMed2002

Comparison of two direct methods for HDL cholesterol measurement with an indirect precipitation method in diabetic patients.

The conventional precipitation method for measuring HDL cholesterol involves a centrifugation step which prevents automation of the method. Several methods have been introduced for measuring HDL cholesterol without the need for a centrifugation step. These new methods are therefore automatable and can process a large number of samples in a short period of time. Measuring HDL cholesterol is an important aspect of management of diabetes mellitus. In this study, we compared 2 direct methods for measuring HDL cholesterol with a conventional precipitation technique in 63 patients with either Type 1 or Type 2 diabetes mellitus. Both direct methods showed acceptable precision but they both showed positive bias compared to the conventional precipitation method. The greatest degree of bias occurs at low HDL cholesterol levels, which are more important for Type 2 patients. Such differences may affect cardiovascular risk calculation in patients with diabetes. Further studies are required to investigate if a correction factor needs to be introduced when these direct assays are used to measure HDL cholesterol in patients with Type 2 diabetes mellitus.

Antibodies↗
PubMed1999

[Studies on precipitate of Huanglian-Huangqin couples in decoction].

OBJECTIVE: Chemical composition of precipitate was researched when Huanglian-Huangqin was decocted. METHOD: Ployamide column chromatography, TLC and TOF-MS were used. RESULT: The precipitate contains berberine, palmatine, jalrorrhizing, epiberberine, copticine, baicaling and wogonoside. CONCLUSION: The precipitate is effective composition in Chinese medical decoction. The research provides new data on medical effects of Huanglian-Huangqin couples.

Alkaloids↗
PubMed2002

Calcium phosphate precipitation method for the treatment of dentin hypersensitivity.

PURPOSE: To evaluate the feasibility of the calcium phosphate precipitation (CPP) method as a treatment for dentin hypersensitivity using vital teeth of beagle dogs. Also, gingival tissue response to two types of CPP methods was examined histologically. MATERIALS AND METHODS: Dentin tubules of the dogs' vital teeth were exposed by shallow cavity preparation followed by etching with 50% citric acid to simulate the condition of hypersensitive dentin. After CPP treatment was applied to the vital tooth, the dentin surface and longitudinal sections were observed by SEM to evaluate the occluding ability of the CPP method. The precipitate was also analyzed by energy-dispersive X-ray microanalysis to obtain compositional information. The gingival tissue before and after CPP method was examined histologically with light microscopy. RESULTS: Dentin tubules were occluded homogeneously and completely with an apatitic mineral after application of the CPP treatment in vital teeth. However, the depth of the precipitate in dentin tubules from the dentin surface was approximately half that seen in extracted teeth. No histological change was observed in gingival tissues when NaHCO3 was used as a post-treatment solution of the CPP method, whereas another CPP method using NaOH solution resulted in atrophy and degeneration of the epithelium of gingival tissue.

Analysis of Variance↗
PubMed1976

Specificity and reproducibility of acetone precipitation in identifying surface-active phosphatidylcholine in amniotic fluid.

We show the thoretical and actual variability in the amount of surface-active lecithin precipitated in the acetone-precipitation step of determining lecithin/sphingomyelin (L/S) ratios in the clinical laboratory. Lecithins precipitated may range from 60 to 90% of the total surface-active lecithins present. The range is sufficient to account for the occasional "immature" L/S ratios (less than 2/1) found in amniotic fluid from women bearing mature fetuses.

Acetone↗
PubMed2003

Optimization of phosphorus precipitation from swine manure slurries to enhance recovery.

Laboratory experiments were conducted using magnesium chloride (MgCl2 x 6H2O, 64% solution) to force the precipitation of phosphorus and reduce the concentration of soluble phosphorus (PO4(3-)) in two swine wastes. One of the swine wastes tested contained a high concentration of PO4(3-) (initially approximately 1,000 mg/L), and the other swine waste tested contained a low concentration of PO4(3-) (initially approximately 230 mg/L). The precipitation reactions were performed to determine the required reaction time, pH, magnesium addition rate and seed material for future precipitate recovery work. For the high and low concentration waste, a 10-minute reaction time at a pH of 8.6 was sufficient to remove 98 and 96% of the PO4(3-) from solution. A molar ratio of Mg2+:PO4(3-) of 1.6:1 was determined to be effective for PO4(3-) removal from both the low and high strength wastes. At a molar ratio of 1.6:1, the PO3- in the high concentration waste was reduced from 590 to 12 mg/L. In the low concentration waste, the PO4(3-) concentration was reduced from 157 to 15 mg/L. Seeding the reaction did not significantly enhance the recovery process.

Animals↗
PubMed2004

[Determination of contents of lipid peroxidation products in lipoproteins by using precipitation systems].

The impacts exerted by three different systems of precipitation of apo-B-containing lipoproteins, i.e. phosphotungstic acid-Mg2+ heparin-Mn2+ and heparin-Ca2+, on the lipid peroxidation (LPO) parameters in the fraction of high-density lipoproteins (HDLP) and in the aggregate fraction of low and very low density lipoproteins (LDLP, VLDLP) were comparatively analyzed. The systems of phosphotungstic acid-Mg2+ and of heparin-Ca2+ were found to have the comparable results related with the content of LDLP and VLDLP. While, the use of the precipitation system based on heparin-Mn2+ entails overstated LPO parameters in both lipoprotein fractions. It was demonstrated on the basis of all studied precipitation systems that the aggregate LDLP and VLDLP fraction had the highest content of isopropanol-soluble LPO products. The highest indices for the LPO heptane-soluble products were registered in the HDLP.

Apolipoproteins B↗