Physical Separation Techniques Research Articles

リサイクリング 物理選別技術 比重選別・重選

リサイクリング 物理選別技術 比重選別・重選

リサイクリング 物理選別技術 電気的選別

リサイクリング 物理選別技術 電気的選別

リサイクリング 物理選別技術 破砕・粉砕

リサイクリング 物理選別技術 破砕・粉砕

18] Purification, isoform characterization, and quantitation of human apolipoprotein A-IV

Publisher Summary Apolipoprotein A-IV (apoA-IV) is a 46,000-dalton plasma protein that has several distinctive biological characteristics. Apolipoprotein A-IV is synthesized in enterocytes of the small intestine and is initially incorporated onto the surface of nascent chylomicrons. Although the specific function of apoA-IV in human lipid metabolism has not been determined, a growing body of evidence suggests that apoA-IV may play a role in the metabolism of high-density lipoproteins (HDL). The signature biophysical property of human apoA-IV is its labile interaction with the lipid surfaces. Apolipoprotein A-IV is an extremely hydrophilic apolipoprotein, TM and its affinity for lipid surfaces is considerably weaker than other apolipoproteins; consequently, it is easily displaced from lipoproteins by other apolipoproteins and by physical separation techniques. Apolipoprotein A-IV is purified from thoracic duct chylomicrons, chylous effusions, hypertriglyceridemic serum, and the urine of patients with chyluria. It has been found that the adsorption of apoA-IV from lipoprotein-depleted plasma to a triglyceride-phospholipid emulsion affords a convenient and rapid method for the initial purification of this apolipoprotein. This chapter describes the effective methods for the preparation, isoform characterization, and quantitation of human apoA-IV.

Phosphorus removal by dispersed air oxidation

Researchers at The University of Alabama have recently developed a two-step method for the treatment of phosphorus sludge. The process includes the bulk removal of phosphorus by physical separation techniques followed by the remediation of the residual P4 in the sludge using a novel, wet, air-oxidation technique known as “HSAD.” Tests made on electric-furnace, phosphorus sludge samples have demonstrated that an essentially complete and fast removal of the contained P4 can be achieved by the HSAD wet oxidation treatment. Further studies were made to determine the applicability of the two-step process to sludges of different origins, pretreatments, storage conditions and P4 contents. The present work, discusses the mechanisms and factors controlling the HSAD, wet, air-oxidation remediation approach.

Applications of nuclear analytical techniques in environmental research. Plenary lecture.

Among nuclear analytical techniques, neutron activation analysis (NAA) is particularly useful for environmental studies. It affords low detection limits for many elements, high specificity and few sources of systematic error, which means that high accuracy is attainable. Neutron activation analysis is particularly useful for trace and ultra-trace analysis of environmental samples (water, soils, rocks and biological material). In trace element work associated with pollution, instrumental NAA is a powerful technique for multi-element surveys, in particular when combined with other spectroscopic techniques. Nuclear techniques, as with most analytical techniques, cannot be used to distinguish between different physico-chemical forms of an element per se. When used in combination with appropriate separation techniques, however, nuclear techniques can provide valuable information about trace element speciation in environmental and biological systems. From dynamic tracer experiments, i.e., addition of chemically well defined labelled compounds to environmental systems, valuable information can be obtained on the distribution of species and on microchemical processes influencing the physico-chemical forms. In these laboratories, speciation studies on trace elements in natural waters have been carried out by using instrumental NAA in combination with physical separation techniques, such as dialysis and ultrafiltration, in situ and in the laboratory. Dynamic radiotracer experiments have provided important information about processes influencing the speciation of trace elements in aquatic systems. Sequential extraction techniques have proved to be useful in studies on sediments and soils when combined with NAA. Sequential extractions also provide significant information about the physico-chemical behaviour of radionuclides supplied to natural soils from the Chernobyl accident.

New methods for the quantitation of microbial nucleic acids

Abstract

Electrostatic separators for insulating fluids

Electrostatic separators have been used in purifying hydraulic fluids, fuels, petroleum refining and coal liquefaction streams, lubricating oils, and other insulating liquids. The designs, applications, and separation efficiencies of these separators are discussed. The separators are categorized as employing either spatially uniform or nonuniform electrical fields, or electrical fields in conjunction with other physical separation techniques. They require low inlet pressures, draw low current, and are resistant to plugging. They are rugged, allowing use in high-temperature and -pressure applications. Many designs allow continuous or semicontinuous operation. Electrostatic separators can separate particles of similar density, shape and size by differences in electrical properties. >

Kinetics of vanadate dissociation: Estimation of the rate by inhibitor inactivation

Vanadate (+5) is a potent inhibitor of a variety of ATPases including dynein ATPase. We describe a method useful for estimating the functional dissociation rate of vanadate from the active site which does not rely on classical physical separation techniques. The method involves spectrophotometrically monitoring the enzymatic activity as the inhibitor dissociates from the enzyme and is inactivated by norepinephrine. Norepinephrine effectively reverses vanadate inhibition by reducing vanadate (+5) to oxovanadium (+4). This reduction by norepinephrine is sufficiently fast for these purposes—addition of vanadate after norepinephrine shows no inhibition of ATPase activity. The mathematical estimation procedure is generally useful for estimation of dissociation rates of other reversible inhibitors which can be quickly inactivated after dissociation from the enzyme. The rate of dissociation of vanadate from dynein with ATP and 2-N 3ATP as substrates using this method was estimated to be in the ranges 0.0023–0.0042 and 0.0057–0.0075 s −1, respectively. These rates permit estimation of the rates of vanadate association with dynein by using the reported dissociation constant for vanadate. The results are consistent with the very fast and potent inhibition of dynein ATPase activity observed.

Monoclonal antibody isolation of type II pneumocytes.

A monoclonal antibody that identifies a membrane molecule unique in rat lung for type II alveolar epithelial cells was used to isolate these cells from enzymatically dispersed lung cells by fluorescence-activated cell sorting. Although multistep physical separation techniques have permitted the isolation of large quantities of these cells and flow cytometry has been used by others to isolate lamellar body-containing cells, the application of this antibody-directed sorting has distinct advantages. Because the marker molecule is expressed on immature type II cells prior to the development of lamellar bodies, the antibody will also permit their isolation and study.

Pre- versus postsynaptic localization of benzodiazepine and beta-carboline binding sites.

[3H]Flunitrazepam (FNP) and [3H]methyl beta-carboline-3-carboxylate (MCC) binding was examined in soluble and particulate fractions from membranes solubilized with Triton X-100 or in subfractions of synaptosomal membranes obtained by a physical separation technique. Results using both methods demonstrate that benzodiazepine and beta-carboline sites reside on both pre- and postsynaptic membranes. Further, subfractionation experiments indicate that the binding sites for both ligands are unequally distributed within the synapse and among brain regions. For example, in cerebral cortical presynaptic membranes there are twice as many FNP as MCC sites whereas in postsynaptic membranes this ratio is reversed. The number of FNP and MCC sites are equal in the presynaptic fraction from cerebellum. The postsynaptic membranes derived from cerebellum have three times the number of FNP compared to MCC sites. In hippocampus this ratio varies between 1.5 and 2.8 in each subfraction. These results support the idea that benzodiazepine and beta-carboline binding sites represent different recognition sites.

Chemical methods in association with physical methods in drug analysis

Physical methods, namely spectroscopy and separation techniques such as high-performance liquid chromatography, in which the analyte is not chemically changed during analysis, have gained increasing popularity in the field of pharmaceutical analysis. Nevertheless, chemical manipulation in combination with such methods will continue to play a vital role, as will be demonstrated with examples selected from methods developed for two new, cardioactive drugs, nadolol and captopril, and from other recent literature references.

Removal of mineral matter from bituminous coals by aqueous chemical leaching

Most of the ash-forming minerals in bituminous coals are insoluble in water or acids, but a high proportion (more than 90%) can be extracted with aqueous sodium hydroxide solutions at 200–300°C under pressure. The major minerals extracted —silica and kaolin — are converted into sodium alumino-silicates (sodalites) which form a separate insoluble phase in contact with water or alkali, but which are readily soluble in aqueous acids. Minor mineral components are also partly removed. The spent leachants can be regenerated for recycling; the extracted minerals form a solid by-product. The chemical extraction steps may be coordinated with conventional coal-cleaning procedures which use physical separation techniques. Experiments with three Australian coals from the Liddell and Lithgow seams (NSW) and the Theodore seam (Queensland), and a vitrinite concentrate from Liddell, gave beneficiated products with ash yields of 0.25–0.75%. Demineralized coal may have applications as a low-ash fuel or carbonaceous raw material.

Separation of immunoreactive lymphocytes from human pluripotent stem cells (CFU-GEMM) by means of counterflow centrifugation.

Counterflow centrifugation with continuous monitoring of the output for cell number and cell scatter was used to separate low density (d less than 1.070 g/ml) human bone marrow cells in two fractions: one containing the majority of small size lymphocytes and the other the majority of the larger sized committed progenitor cells. The recovery of the pluripotent stem cells (CFU-GEMM) in the large cell fraction was complete. The mitogenic reactivity of this putative stem cell fraction had decreased to 6% and 11%, of the original value as measured with phytohemagglutinin stimulation and one way mixed lymphocytic culture respectively. Counterflow centrifugation offers a physical separation technique, by which the majority of the immunoreactive cells can be separated from the pluripotent hematopoietic stem cells.

Ethanol Fraction of Lacustrine Colloidal Fibrils

Ethanol fractionation of colloidal organic fibrils can provide a highly purified fraction in appropriate quantities for standard chemical analyses of fibril structure and function. Using a sequential ethanol precipitation procedure, applied to lacustrine fibrils isolated and concentrated by physical separation techniques, we obtained a fibril fraction (approximately 60% yield). Its characteristics were as follows: (1) absence of any major category of colloidal impurity detectable by transmission electron microscopy, (2) relative freedom from fibrils of atypical morphology, (3) relative freedom from a class of small granules, typically associated with lacustrine fibrils and with some other kinds of polyanionic fibrillar colloids found in nature, (4) freedom from derivatization reactions, and (5) freedom from an undesirable exposure to caustic reagents. Our objective was to arrive at a nondegradative fractionation procedure that yielded a fraction relatively free of other colloidal components found in lake water. This fraction would then be appropriate for assays of heavy metal binding and bioavailability.

Autologous bone marrow transplantation in leukemia.

In patients without HLA-identical donors autologous bone marrow transplantation should be considered as an alternative to conservative treatment of recurrent malignancies. Any patient in complete remission is suitable for an autologous bone marrow transplantation. Bone marrow is aspirated from the patient during complete remission, frozen, and stored at -196 degrees C, and it can be used for hematopoietic reconstitution after high-dose chemotherapy and radiotherapy of the patient. In patients with solid malignant tumors or leukemia the elimination of clonogenic tumor cells from the graft by means of physical separation techniques has not been successful. However, studies in mice and more recently in patients indicate that antibodies destroy residual leukemic cells of the bone marrow transplant without jeopardizing the capacity for regeneration. During our first study in children with acute lymphoblastic leukemia, bone marrow was taken from 50 patients in remission and cryopreserved. Preservation time ranged from 1 to 60 months and the mean number of aspirated nucleated bone marrow cells was 4 X 10(8)/kg body weight (1.9 - 7.4 X 10(8)/kg). After cryopreservation the stem cell viability of the standard samples was 80% - 100%. Autologous bone marrow was transplanted in five patients with common ALL (cALL). The transplant was prepared by incubation with specific antisera of high cytotoxic, selective activity against cALL cells. Our preliminary results show that bone marrow cells aspirated in remission and prepared with antileukemic antisera stimulate repopulation of the recipient's bone marrow and effect hematopoietic regeneration.

Isolation of Colloidal Fibrils from Lake Water by Physical Separation Techniques

A colloid fraction, highly enriched for organic fibrils, can be isolated routinely by physical means. The physical isolation scheme used here provides gram quantities of un-denatured samples in a short time from the epilimnion of a small mesotrophic lake. The total scheme is described in detail and is accompanied by an assessment of yield and contamination at each individual step using a transmission electron microscope as a monitor. The potential importance of organic fibrils is emphasized by a 1980 summer measure showing a fibril fraction to contain three times more carbon than the conventional particulate organic carbon fraction (POC) and 33% of the total dissolved organic carbon (DOC).Key words: colloids, hollow-fiber ultrafiltration, dissolved organic carbon

The use of physical separation techniques in trace metal speciation studies

Size fractionation techniques used in speciation studies of trace metals in natural waters have been reviewed. Centrifugation, filtration, ultrafiltration (UF), dialysis and gel filtration chromatography (GFC) have been considered with respect to trace metal contamination, adsorption effects and size selectivity. Size differentiation during centrifugation is impeded due to density effects on particle settling rates. Filtration is the most commonly used method to fractionate trace metal species, but often only “issolved” and “particulate” fractions are identified. Filters may be decontaminated with dilute nitric acid and adsorption effects may be minimised by preconditioning with a dilute calcium nitrate solution. Several studies concerning the size selectivity of filters indicate that at present only Nuclepore polycarbonate filters are suitable for size spectrum investigations. Those difficulties outlined above are also experienced with UF methods but generally have not been so well resolved. particularly with respect to adsorption. Adsorption during UF causes an overestimation of the molecular size of metal complexes. Dialysis techniques have been utilized with some success in order to isolate trace metal species in true solution but have seen only limited applications in comprehensive speciation schemes. GFC offers considerable potential in physicochemical speciation studies. The major advantage lies with the ability to determine metal concentrations over a continuous size spectrum rather than at discrete size ranges. In contrast to other methods, adsorption during GFC will cause the molecular weight of organometallic complexes to be underestimated. Several examples of the environmental application of each technique have been considered, thereby illustrating the value of examining the size distribution of metal species in natural waters.

Delivery of 14C-lignocaine and blood flow to canine organs after coronary occlusion: a physical separation technique to measure drug concentration and microsphere blood flow in the same tissue sample.

The purpose of this study is to characterise the distribution of lignocaine relative to blood flow in several organs after coronary occlusion in the dog. To achieve this, it was necessary to develop a convenient, new technique to measure microsphere blood flow and l4C-lignocaine in the same small tissue sample. Seven anaesthetised, open-chest dogs were studied after coronary occlusion. Two minutes after occlusion 14C-lignocaine was injected, 75 mg (150 μ Ci) iv in four dogs (Group II). Three minutes after coronary occlusion radioactive microspheres were injected into the left atrium in order to measure tissue blood flow. Each animal was sacrificed 12 min after coronary occlusion, and samples were removed rapidly from heart, brain, abdominal wall muscle, liver and kidney. After counting each tissue sample in a gamma well counter for microsphere activity, we then dissolved each tissue sample completely. The supernatant contained 14C-lignocaine but not microsphere gamma activity because microspheres settled to the bottom of the tube according to their specific gravity of 1.28. Thus, the supernatant could be used to measure 14C-lignocaine by liquid scintillation counting. Group I dogs received gamma-labelled microspheres but no 14C-lignocaine and showed no 14C activity when the “supernatants” of their samples were counted in the liquid scintillation counter. Tissue blood flow was highest in kidney and lowest in skeletal muscle, while 14C-lignocaine concentration was highest in liver and lowest in muscle. Although lignocaine concentration correlated significantly with organ blood flow (r = 0.46, P<0.05), the correlation was not strong because cumulative tissue uptake (estimated by the index, lignocaine/blood flow) was increasing as blood flow decreased below 0.50 cm3·min−1·g−1. We conclude that this convenient technique should improve the design of experiments by measuring blood flow and 14C drug concentration in the same small tissue sample, using widely available instrumentation. These measurements may clarify the mechanisms of the therapeutic and toxic effects of drugs, hormones and other physiological mediators, particularly in situations where regional blood flow distribution might be abnormal.

A partial characterization of the cyclic nucleotide phosphodiesterases of Drosophila melanogaster

The cyclic nucleotide phosphodiesterases in crude homogenate, soluble material, and particulate preparations of adult Drosophila melanogaster flies, hydrolyze cyclic AMP with nonlinear kinetics. Cyclic GMP is hydrolyzed by the phosphodiesterases in crude homogenate and soluble material with linear kinetics. Physical separation techniques of gel filtration, velocity sedimentation, and ion-exchange chromatography reveal that Drosophila soluble fraction contains two major forms of cyclic nucleotide phosphodiesterase. Form I hydrolyzes both cyclic AMP and cyclic GMP. Inhibition experiments suggest that the hydrolysis of both cyclic nucleotides by Form I occurs at a single active site. The K m 's for hydrolysis of both substrates are about 4 μ m. This form has a molecular weight of about 168,000 as estimated by gel nitration. Form II cyclic nucleotide phosphodiesterase is specific for cyclic AMP as substrate. Gel filtration indicates that this form has a molecular weight of about 68,000. The K m for cyclic AMP is about 2 μ m.