Magnetic Separation Technique Research Articles

Sperm ubiquitination in epididymal feline semen

Ubiquitin is a 8.5-kDa peptide that tags other proteins for proteasomal degradation. It has been proposed that ubiquitination might be responsible for the elimination of defective spermatozoa during transit through the epididymis in humans and cattle, but its exact biological function in seminal plasma has not yet been clarified. In the domestic cat (Felis catus), the percentage of immature, unviable, and abnormal spermatozoa decreases during the epididymal transit, indicating the existence of a mechanism that removes defective spermatozoa. Magnetic cell separation techniques, based on the use of magnetic beads coated with anti-ubiquitin antibodies, may allow the selective capture of ubiquitinated spermatozoa from semen, thus contributing to the identification of a potential correlation between semen quality and ubiquitination process. Moreover, the selective identification of all the ubiquitinated proteins in different epididymal regions could give a better understanding of the ubiquitin role in feline sperm maturation. The aims of this study were as follows: (1) to verify the possibility of separating ubiquitinated spermatozoa with magnetic ubiquitin beads and identify the morphological and acrosomal differences between whole sample and unbound gametes, (2) to characterize all the ubiquitinated proteins in spermatozoa retrieved in the three epididymal regions by a proteomic approach. The data indicated the presence of ubiquitinated proteins in cat epididymal semen. However, a correlation between abnormal and ubiquitinated spermatozoa has not been found, and ubiquitin cannot be considered as a biomarker of quality of epididymal feline spermatozoa. To the author's knowledge, this is the first identification of all the ubiquitinated proteins of cat spermatozoa collected from different epididymal regions. The proteomic pattern allows a further characterization of cat epididymal semen and represents a contribute to a better understanding of the ubiquitin role in feline sperm maturation.

Identifying sources and controlling factors of arsenic release in saline groundwater aquifers

Abstract. An integrated hydrogeochemical study was carried out to realize the occurrence of arsenic (As) in a saline aquifer. Saline groundwater was mostly concentrated in the uppermost aquifer, and non-saline water was in the lower aquifer in the study area. High As concentrations were found in both the uppermost and lower aquifers. No correlation among salinity, well depth and As concentration was observed. Various forms of Fe oxyhydroxides were identified in the magnetic fractions, which were concentrated by high gradient magnetic separation (HGMS) technique, revealing that the redox cycling of Fe occurred in the subsurface. High levels of Fe, HCO3-, DOC and NH4+ concentrations accompanying alkaline pH in the As-rich groundwater were consistent with the mechanism triggered by the microbially mediated reductive dissolution of Fe oxyhydroxides. A proposed threshold value of 50μg L-1 As concentration was used as an indicator for identification of active proceeding reductive dissolution of As-bearing Fe oxyhydroxides in the saline aquifer. Desorption behaviors of As were relevant to its valence in the sediments and the co-existence of anions. Experimental and numerical results showed that additions of Cl- and SO42-, which represent the main anions of saline water, had minor effect on leaching sedimentary As. Although bicarbonate addition resulted in less As desorption than that of phosphate on a molar basis, the contribution of bicarbonate to the total release of As was greater than phosphate due to the much higher concentration of bicarbonate in shallow groundwater and the associated microbial mediation. Collectively, the chemical effect of saline water on the As release to groundwater is mild in the coastal aquifer.

Characterization and Beneficiation of an Egyptian Nepheline Syenite Ore

Nepheline syenite ore is an essential constituent in ceramics and glass raw material meals, as a flux and as a source of alumina. The natural nepheline syenite rocks contain some undesired minerals, which are usually eliminated or reduced to the allowable limits by beneficiation. The present paper is concerned with characterization and beneficiation of an Egyptian nepheline syenite rock, at Abu Khruq locality, Eastern Desert, Egypt. The ore is exceptionally hard, with high crushing strength of 875 kg/cm2, and iron oxide content of about 6.5%. The grain size of the constituents is relatively large. In some samples, the iron oxides are disseminated within the feldspars and nepheline syenite crystals, or in cracks and fissures within the feldspars crystals. The rock contains some environmental hazardous elements such as uranium, thorium, and radon. Magnetic separation and flotation techniques were applied, separately or in combination. Under optimum operating conditions, magnetic separation followed by reverse anionic flotation gave a concentrate assaying 0.2% Fe2O3 and about 24% Al2O3 at alumina recovery of about 80%. The radioactive elements were reduced in the concentrate to lower levels than their levels in the original rock.

The influence of pH on manganese removal by magnetic microparticles in solution

An extensive experimental work is reported that aims to assess the efficiency in manganese (Mn) removal from aqueous solution by carbonyl iron microparticles using magnetic separation techniques. A set of batch experiments are performed to explore the effect of pH, adsorbent concentration, surface coating and contact time for achieving the highest Mn removal efficiency. Mn removal efficiency is extremely high (>98%) for pH values larger than 9 as a result of the chemisorption of Mn oxides onto magnetic microparticles. In contrast, Mn removal efficiency for pH < 9 was significantly reduced as Mn remains as a soluble cation. In this manuscript we demonstrate that the efficiency clearly increases when increasing the adsorbent concentration and when using MnOx(s) coated magnetic particles instead of bare particles. Desorption rates from Mn-loaded magnetic particles at different pHs were always lower than 15%. Furthermore, Mn removal efficiency remained at a very high value (>95%) when reused particles were employed in the adsorption process.

Magnetic imprinted surface enhanced Raman scattering (MI-SERS) based ultrasensitive detection of ciprofloxacin from a mixed sample

A new method for fast extraction and ultra-sensitive detection of ciprofloxacin based on magnetic imprinted surface-enhanced Raman scattering (MI-SERS) has been developed in this paper. This method is a combination of three techniques, which are a magnetic separation technique, a molecular imprinting technique and a surface-enhanced Raman scattering technique. We designed and fabricated core–shell structured magnetic molecularly imprinted polymers (MIPs) which can be applied to specifically recognise ciprofloxacin and extract it from a mixed system. The whole extraction and clean-up procedures are assisted by a magnetic field, which makes it much easier than traditional centrifugal separation. In addition to this, surface-enhanced Raman scattering (SERS) was applied as the detection tool, which makes the detection limit for ciprofloxacin by this method as low as 10−9 mol L−1. Furthermore, we integrated these core–shelled magnetic-MIPs on a magnet chip and detected ciprofloxacin from fetal bovine serum. The whole detection process can be finished within ten minutes and the limit of detection by this chip can reach 10−7 mol L−1.

Magnetic Separation Technique Using High Temperature Superconducting Bulk Magnets and Application to Plating Liquid Waste Treatment

Magnetic Separation Technique Using High Temperature Superconducting Bulk Magnets and Application to Plating Liquid Waste Treatment

Magnetic nanomaterials in catalysis: advanced catalysts for magnetic separation and beyond

While magnetic separation techniques have long been in use, intensive research into superparamagnetic nanomaterials has accelerated the development of magnetically recoverable catalysts. Preparation techniques are currently undergoing rapid development and magnetic separation has been studied to facilitate the handling and recovery of enzyme, organo-, metal complex-, and nanoparticle-catalysts. In this article, we emphasize the preparation of support materials, because the choice of the correct support and the immobilization strategy are of primary importance in the development of high-quality magnetically recoverable catalysts. We summarize the representative methods for the synthesis of well-defined uncoated and coated magnetic nanomaterials. Recent scientific progress on the preparation of surface-modified magnetic nanomaterials and the most common synthetic approaches to attach or immobilize non-magnetic catalytic active phases onto magnetic nanomaterials were discussed. Moreover, better control and understanding of the magnetic properties is now an essential tool not only in selecting the best preparation route for recoverable catalysts, but also for designing reactors (e.g., magnetic fluidized-bed reactors) and for developing magnetic field-driven technologies (e.g., changes in the catalytic output operating under an applied magnetic field).

The Development of the Separation Apparatus of Phosphor by Controlling the Magnetic Force

The phosphor wastes contain the multiple kinds of rare-earth phosphors with high market value. Because of increasing demand for rare-earth, the technique to recover and reuse the rare-earth in the phosphor wastes is required.In this study, we focused on the difference of physical property such as magnetic susceptibility and density for each type of phosphor and tried to separate and recover the phosphors by using the magnetic separation technique utilizing the difference of the traction force to the magnet acting on the particles. Magneto-Archimedes method is method separation technique utilizi g the difference of magnetic susceptibility and density. We developed the magnetic separation apparatus by applying this technique.To develop the practical separation apparatus, the continuous process is required. Hence the fundamental experiment utilizing High Temperature Superconducting (HTS) Bulk Magnet which can generate the strong magnetic force was conducted. As a result, we succeeded the continuous separation of the phosphor wastes.

Recovery of high grade iron compounds from LD slag by enhanced magnetic separation techniques

A representative sample of LD slag provided from French steel industry was treated by different physical separation techniques especially used in mineral processing. The results of characterisation study show that the LD slag may contain up to 35% of iron compounds. The X-ray diffraction reveals the presence of the following crystallized mineral phases: CaO, MgO, Al2O3, SiO2, MnO, and P2O5. Larnite (Ca2SiO4), di-calcium aluminoferrite (brownmillerite: Ca2Fe2−xAlxO5 with x=0.6) and a solid solution (Fe, Mn, Mg)O structurally close to the wüstite (FeO) and some residual lime (CaO).The results of grinding tests show that the manner of grinding is very important. Soft Grinding (SG) or sequential grinding is most suitable to reduce the particle size of LD slag avoiding the overproduction of fine particles, which hinder the effectiveness of magnetic separation techniques. The combination of Low and High Intensity Magnetic Separation (LIMS and HIMS) of ground LD slag at 63μm in wet process may recover ferromagnetic particles (iron oxides) at LIMS and paramagnetic particles at HIMS, while the non-magnetic fraction contains mostly calcium silicates.From this investigation, two flow-sheets of treatment of LD slag are suggested to recover high grade iron material for recycling in metallurgical processes. Calcium and silicon oxide rich product will be directed to the cement industry.

Processing a rare earth mineral deposit using gravity and magnetic separation

Rare earth (RE) mineral deposits are typically processed using several different unit operations including flotation, gravity, magnetic and electrostatic separation techniques. Two of the most important beneficiation techniques for RE minerals are gravity and magnetic separation. Many RE minerals are found alongside low specific gravity gangue minerals thereby permitting the use of gravity separations to concentrate the heavy value RE minerals. Magnetic separation is used primarily to remove ferromagnetic gangue minerals as well as to separate individual paramagnetic rare earth minerals.This work investigated the use of a wet high intensity magnetic separation (WHIMS) in conjunction with gravity pre-concentration steps (Knelson and Falcon centrifugal concentrators) to beneficiate a rare earth ore. The results of these separation steps are related to the magnetic properties of RE minerals, based on literature and measurements conducted using a vibrating sample magnetometer (VSM).

On-chip magnetophoretic isolation of CD4 + T cells from blood

This paper presents the design, fabrication, and testing of a magnetophoretic bioseparation chip for the rapid isolation and concentration of CD4 + T cells from the peripheral blood. In a departure from conventional magnetic separation techniques, this microfluidic-based bioseperation device has several unique features, including locally engineered magnetic field gradients and a continuous flow with a buffer switching scheme to improve the performance of the separation process. Additionally, the chip is capable of processing significantly smaller sample volumes than conventional methods and sample losses are eliminated due to decreased handling. Furthermore, the possibility of sample-to-sample contamination is reduced with the disposable format. The overall dimensions of the device were 22 mm by 60 mm by 1 mm, approximately the size of a standard microscope slide. The results indicate a cell purity of greater than 95% at a sample flow rate of 50 ml/h and a cell recovery of 81% at a sample flow rate of 10 ml/h. The cell purity was found to increase with increasing the sample flow rate. However, the cell recovery decreases with an increase in the flow rate. A parametric study was also performed to investigate the effects of channel height, substrate thickness, magnetic bead size, and number of beads per cell on the cell separation performance.

Magnetic separation technique on binary mixtures of sorbitol and sucrose

We separated binary mixtures of sucrose (disaccharide) and sorbitol (monosaccharide) by the effect of magneto-Archimedes levitation as a first step in proposing a new separation technique in food processing. In this technique, the mixtures are levitated at a specific position in a superconducting magnet, and the separation is realized by controlling the magnitude of magnetic force. Owing to the differences in their magnetic susceptibility, the levitating position of the components in the mixtures is uniquely identifiable. The aggregates of sorbitol were levitated upwards and those of sucrose were levitated downward. As the magnitude of the magnetic force was reduced, the sucrose and then the sorbitol fell in that order, and therefore they could be collected separately. The mechanism of this effect is attributed to the 8.2% difference in the volumetric magnetic susceptibilities of sucrose and sorbitol and the compressed oxygen gas. In the separation process, the falling particulates were distributed in an hourglass shape. This phenomenon was induced by the horizontal component of the magnetic force. The curvilinear surface was in good agreement with a numerical simulation.

Developing of A Novel Clinical Kit for Assaying of Alpha-fetoprotein Based on Luminescent and Magnetic Nanoparticles

Alpha-fetoprotein (α-FP, AFP) was the only serological marker currently available for the detection of hepatocellular carcinoma (HCC). As a novel biological luminescent label, the favorable properties of water-soluble CdTe quantum dots (QDs) have advantages over conventional fluorescent materials. Meantime, the magnetic separation technique has widely been applied to various aspects in biotechnology in recent years. In this paper, CdTe QDs and dextran–Fe3O4 magnetic nanoparticles were both applied on immunoassay for the determination of AFP concentration. Firstly, a mouse anti-human AFP antibody (primary antibody) was immobilized on magnetic nanoparticles, which were used as solid support. Secondly, another mouse anti-human AFP antibody (secondary antibody) was attached to the surface of the CdTe QDs via electrostatic interaction. It was found that when the pH value was 6.0, the volume ratio of CdTe (3×10-4 mol/L) to antibody (2 mg/mL) was 50:3, and the reaction time was more than 10 min, the complex of the secondary antibody and CdTe was formed and the strongest PL intensity was obtained. Thirdly, the above two complexes were conjugated with a serial of AFP concentrations. Then the relationship between the PL intensity and the AFP concentration was determined and the calibration equation— Y=k(X-9.31)/V—was obtained. Finally, ten samples of human serum were tested based on this equation. The results, to a large extent, were consistent with those obtained by Time-resolved Fluorescence. More importantly, the current method could be applied in many other antibody-antigen systems.

Development of a novel phage-mediated immunoassay for the rapid detection of viable Mycobacterium avium subsp. paratuberculosis

The objective of this study was to develop a novel screening method for detection of viable Mycobacterium avium subsp. paratuberculosis (Map) in milk and faeces, as a rapid alternative to Map culture. The new method couples Map-specific peptide-mediated magnetic separation technique with an optimized phage amplification assay followed by detection of released progeny phage by ELISA in a competition assay format using polyclonal antibody produced against the D29 mycobacteriophage involved in the phage assay. Sample matrices were found not to interfere with the developed method, and the dynamic range of the assay was 3×10(2) -6×10(8) phageml(-1) . When low numbers of Map were present (10(2) CFUml(-1) ), the burst size of a single host Map cell was maximal (10(3) phage per cell) resulting in a highly sensitive screening assay. A rapid, sensitive immuno-based screening method suitable for the detection of viable Map in milk and faeces was developed. The novel PMS-phage-ELISA permits sensitive, qualitative detection of viable Map in milk or faeces samples within 48h, representing a substantial decrease in time to detection compared with current culture methods for Map.

ChemInform Abstract: Nano‐Magnetite (Fe3O4) as a Support for Recyclable Catalysts in the Development of Sustainable Methodologies

AbstractReview: 189 refs.

Role of ore mineralogy in selecting beneficiation route for magnesite-dolomite separation

Characterization and beneficiation of magnesite-dolomite sample were performed. The role of ore mineralogy in selecting the most adequate concentration method for magnesite-dolomite separation was found to be detrimental. The microscopic analysis showed that dolomite is stained with goethite and lepidocrocite (weakly magnetic minerals), while magnesite is stained with hematite and magnetite (highly magnetic mineral). A dry magnetic separation technique was used to separate dolomite from magnesite. The magnetic separation of the sample resulted in a magnesite concentrate product assaying 1.12% CaO with 46.02% recovery and CaO/SiO2 molar ratio = 1.62. This magnesite product is suitable for basic refractory. Besides, middling fraction was produced, containing 44.63% magnesite and 10.95% dolomite. This product is suitable for making low-loss forsterite dielectrics.

Adsorptive removal of emerging contaminants from water using superparamagnetic Fe3O4 nanoparticles bearing aminated β-cyclodextrin

Concern is growing over the contamination of the aquatic environment with pharmaceutically active compounds (PhACs) and endocrine disrupting compounds (EDCs) because of their adverse effects on health and environment. In this study, the removal of two PhACs, naproxen and carbamazepine and one EDC, bisphenol A from aqueous solutions was examined by batch adsorption experiments onto 6-Deoxy-6-ethylenediamino-β-cyclodextrin (β-CDen) grafted thiodiglycolic acid (TDGA) modified magnetic nanoparticles (CDen-MNPs).β-CDen being grafted on TDGA-coated Fe3O4 nanoparticle contributed to an enhancement of adsorption capacities because of the inclusion abilities of its hydrophobic cavity with organic contaminants through host–guest interactions. The effect of solution pH on adsorption of contaminants was investigated over the range of pH 3–11. Results show that physicochemical properties of each organic pollutant (pKa, hydrophobicity etc.) were important factors in adsorption process. Bisphenol A (logKow 3.3) was least adsorbed, whereas carbamazepine (logKow 2.45) was most adsorbable. The interactions of these pollutants with MNPs bearing cyclodextrin moieties followed the well-established Freundlich isotherm model and pseudo-second-order kinetic model. Kinetic studies also indicate that molecular size and structure of the contaminant influenced the rate of adsorption process. Furthermore, residue of inclusion complexes among the contaminants and β-CDen were scrutinized using FTIR spectroscopy and van der Waal's interaction was found to be dominant. Our results suggest that CDen-MNPs would provide a new platform for removing of PhACs and EDCs using magnetic separation technique.

Synthesis and characterization of magnetic adsorbent prepared by magnetite nanoparticles and zeolite from coal fly ash

Magnetite nanoparticles were prepared by partial oxidation of Fe(II) ions of an aqueous suspension of hydroxysulfate green rust which was obtained by precipitation of Fe(II) ions. This magnetite was mixed with zeolite synthesized from coal fly ash to obtain the magnetic adsorbent and the final product characterization was made. By analysis of scanning electron microscopy and X-ray diffraction, images of clusters of magnetite nanoparticles were observed and crystallite sizes of 17 nm were determined, respectively. In thermal analysis, the weight ratio of 1:3 for magnetite-zeolite in the magnetic adsorbent was measured and a non-magnetic product at 974 °C was found in both magnetite and magnetic adsorbent. Magnetization measurements described small hysteresis from the clusters of magnetite nanoparticles. Fourier Transform Infrared spectroscopy analysis indicated that the synthesized zeolite is a hydroxy sodalite and evidences of formation of the magnetic adsorbent were observed. The performance of magnetic separation technique was evaluated and it was comparable to the centrifugation process. The magnetic adsorbent indicated a potential application for adsorption of dye Reactive Orange 16 from aqueous solution.

Concentration of 238U and 232Th among constituent minerals of two igneous plutonic rocks exhibiting elevated natural radioactivity levels

The concentrations of 238U and 232Th of the constituent minerals in two plutonic rock samples, from N. Greece, exhibiting elevated levels of bulk rock natural radioactivity were determined by using LA-ICP-MS. The available data of whole rock 238U and 232Th concentrations were also used. The minerals were separated using a combination of heavy liquids of various densities, shaking table and magnetic separation techniques. The great variation in the concentrations of 238U and 232Th is probably indicative of the different distribution of U and Th within the same rock, as well as to secondary post-magmatic processes that were responsible for the redistribution of U and Th. An estimation of the contribution of each mineral constituent to the natural radioactivity levels of the bulk rock is attempted. Thorite and zircon contribute the most to the whole rock 238U and 232Th content, while the contribution of apatite is moderate. The contribution of the rest of the minerals examined (fluorite, quartz, plagioclase, K-feldspar, amphibole, pyroxene, magnetite and biotite) is not important.

Collection of Ni-bearing material from electroless plating waste by magnetic separation with HTS bulk magnet

The magnetic separation experiment to collect the Ni compounds from the waste liquid of electroless plating processes was conducted in the open-gradient magnetic separation process with the high temperature superconducting bulk magnet system. The magnetic pole containing Gd-based bulk superconductors was activated to 3.45T at 35K in the static magnetic field of 5T with use of a superconducting solenoid magnet. The coarse Ni-sulfate crystals were formed by adding the concentrated sulfuric acid to the Ni-phosphite precipitates which yielded from the plating waste liquid by controlling the temperature and the pH value. The open-gradient magnetic separation technique was employed to separate the Ni-sulfate crystals from the mixture of the Ni-sulfate and Ni-phosphite compounds by the difference between their magnetic properties. And we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite by attracting them to the magnetic pole soon after the Ni-sulfate crystals began to grow.