Paramagnetic Particles Research Articles

Detection of urea using urease and paramagnetic Fe3O4 particles incorporated into polyelectrolyte microcapsules

The enzyme urease and paramagnetic Fe3O4 particles were incorporated into microcapsules (3–4μm in size) formed using sodium polystyrene sulfonate and polyallylamine hydrochloride polyelectrolytes. Microcapsules were attracted to the gate of a pH-sensitive field effect transistor by a permanent magnetic field to form a bioreceptor on its surface. The immobilization technique used required no chemical reagents to activate and regenerate transistor’s surface. The volume of the measured sample was 3μl; the total reaction volume, 30μl. Biosensor signals developed over a time of the order of 30–150s. The biosensor enabled the detection of urea within the concentration range of 0.03 up to 100mM. The enzyme activity and signal values of the biosensor did not decrease within 30 days. Measurements of real blood samples yielded a satisfactory correlation of biosensor data and clinical data (correlation coefficient, 0.78).

Preliminary evaluation of a highly automated instrument for the selection of CD34+ cells from mobilized peripheral blood stem cell concentrates

Cell selection is an important part of manufacturing cellular therapies. A new highly automated instrument, the CliniMACS Prodigy (Miltenyi Biotec), was evaluated for the selection of CD34+ cells from mobilized peripheral blood stem cell (PBSC) concentrates using monoclonal antibodies conjugated to paramagnetic particles. PBSCs were collected by apheresis from 36 healthy subjects given granulocyte-colony-stimulating factor (G-CSF) or G-CSF plus plerixafor. CD34+ cells from 11 PBSC concentrates were isolated with the automated CliniMACS Prodigy and 25 with the semiautomated CliniMACS Plus Instrument. The proportion of CD34+ cells in the selected products obtained with the two instruments was similar: 93.6 ± 2.6% for the automated and 95.7 ± 3.3% for the semiautomated instrument (p > 0.05). The recovery of CD34+ cells from PBSC concentrates was less for the automated than the semiautomated instrument (51.4 ± 8.2% vs. 65.1 ± 15.7%; p = 0.019). The selected products from both instruments contained few and similar quantities of platelets (PLTs) and red blood cells. The depletion of CD3+ cells was less with the automated instrument (4.34 ± 0.2 log depletion vs. 5.20 ± 0.35 log depletion; p < 1 × 10(-6) ). Removal of PLTs from PBSC concentrates by washing was associated with better CD34+ cell recovery. We explored the reasons for lower CD34+ cell recovery by the Prodigy and found that the nonselected cells for the Prodigy contained more PLTs than those for the CliniMACS Plus. CD34+ cells can be effectively selected from mobilized PBSC concentrates with the CliniMAC Prodigy, but the recovery of CD34+ cells and depletion of CD3+ cells was lower than with the semiautomated CliniMACS Plus Instrument.

Polyelectrolyte microcapsules with urease and paramagnetic particles as a basis for a potentiometric biosensor for determining urea

A biosensor is proposed based on a pH-sensitive field-effect transistor for detecting urea. The bioreceptors are polyelectrolyte microcapsules (size of 3–4 μm) with encapsulated paramagnetic particles of Fe3O4 and enzyme urease, capable of biotransforming urea. The bioreceptor was formed on the surface of a transistor gate using a constant magnetic field; the sedimentation of microcapsules in the gate zone proceeded because of the presence of paramagnetic particles in the bioreceptor. The microcapsules were prepared separately and stored at 4°C. This method of biosensor formation took several seconds and did not require additional chemical reagents for treating the electrode surface before and after the measurement. The lower limit of the detection of urea was 0.03 mM in the range of 0.03–100 mM. The biosensor is characterized by high sensitivity (~3.58 pH/mM) and time of signal formation of about 30–150 s, depending on the concentration of urea. The biosensor was tested on milk samples.

Optical, Structural and Paramagnetic Properties of Eu-Doped Ternary Sulfides ALnS₂ (A = Na, K, Rb; Ln = La, Gd, Lu, Y).

Eu-doped ternary sulfides of general formula ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y) are presented as a novel interesting material family which may find usage as X-ray phosphors or solid state white light emitting diode (LED) lighting. Samples were synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their physical properties were investigated by means of X-ray diffraction, time-resolved photoluminescence spectroscopy, electron paramagnetic resonance, and X-ray excited fluorescence. Corresponding characteristics, including absorption, radioluminescence, photoluminescence excitation and emission spectra, and decay kinetics curves, were measured and evaluated in a broad temperature range (8–800 K). Calculations including quantum local crystal field potential and spin-Hamiltonian for a paramagnetic particle in D3d local symmetry and phenomenological model dealing with excited state dynamics were performed to explain the experimentally observed features. Based on the results, an energy diagram of lanthanide energy levels in KLuS2 is proposed. Color model xy-coordinates are used to compare effects of dopants on the resulting spectrum. The application potential of the mentioned compounds in the field of white LED solid state lighting or X-ray phosphors is thoroughly discussed.

Magnetic effects in hydroperoxide decomposition in mixed micelles with cationic surfactants

The retardation effect of oxygen and external magnetic field on the yield of radicals in hydroperoxide decomposition in catalytic nanoreactors was discovered. Mixed reverse micelles formed by the cationic surfactants (Surf) and hydroperoxide {mLOOH...nSurf} play the role of nanoreactors. Similar effects of oxygen and external magnetic field (60–150 mT) on the yield of radicals are observed in the catalytic decomposition of hydroperoxide in the presence of acetylcholine. It is noteworthy that the retardation effect of the magnetic field decreases in the presence of paramagnetic particles such as oxygen and relatively stable radicals.

Evaluation of yield and integrity of DNA samples extracted from cord blood segments and red cells fractions using the Maxwell® RSC instrument

Aim The number of cord blood samples received for a variety of applications has increased in our laboratory. This has led us to evaluate an automated method to improve the TAT and yield of the DNA extraction. Our current procedure for cord blood samples requires an overnight incubation that is labor intensive. Cord blood segments and frozen red cell fractions were received from the Duke Cord Blood Bank to help us evaluate the efficiency and yield of the Maxwell Rapid Sample Concentration (RSC) automation recently released by Promega. Method The initial volume of the samples received for the study were; 100 μ l cord blood segments and 600 μ l frozen red cell fractions. The average of the total nucleated cell count was 7.4 × 107cells/ml for the cord segments and 1.6 × 107cells/ml for the red cell fractions. The samples were thawed, RNAse and Proteinase K was added, followed by a 30 min incubation. Then each sample was placed into the Maxwell RSC automation in a designated slot. The Maxwell RSC uses a paramagnetic particle to optimize sample capture, washing, and purification by a cellulose-based binding of nucleic acids. The final elution volume was determined to be 100 μ l and the equipment Blood Protocol was used for all extractions. The total time for the extraction is 35 min (hands off). HLA typing were performed using; RT-PCR, Luminex, SSP and SBT. Results Nine samples were isolated by Maxwell RSC (six cord blood and three cell fractions). The DNA yield from the cord segments ranged from 130 ng/ μ l to 477 ng/ μ l with the total average yield of 34 μ g. The red cells fraction range was from 424 ng/ μ l to 715 ng/ μ l with the total average yield of 50 μ g. The 260/280 OD ratios were within 1.8–2.0 for both sample sources. Each DNA extraction had its integrity evaluated with low melting agarose gel electrophoresis. The three DNA samples were typed by all of our routine HLA typing methodologies generated successful HLA typing. Conclusion The Maxwell RSC appears to have high quality results, easy and reliable operation, flexible protocol, and it reduces the TAT for our laboratory to obtain the DNA from cord blood samples requiring HLA typing.

Merged neutral beams

A detailed description of a merged beam apparatus for the study of low energy molecular scattering is given. This review is intended to guide any scientist who plans to construct a similar experiment, and to provide some inspiration in describing the approach we chose to our goal. In our experiment a supersonic expansion of paramagnetic particles is merged with one of polar molecules. A magnetic and an electric multipole guide are used to bend the two beams onto the same axis. We here describe in detail how the apparatus is designed, characterised, and operated.

Removal of Iron Oxide With Superconducting Magnet High Gradient Magnetic Separation From Feed-Water in Thermal Plant

By the accident of Fukushima Daiichi Nuclear Plant, all the nuclear plants have stopped in Japan. As a result, the operation rate of thermal power plants has been increased. It caused growth in CO 2 emission, which requires some kind of countermeasure. We focused on the iron oxide scales deposited on the piping system and boiler which declines the heat exchange efficiency of thermal power plants. In this study we attempt to remove the iron scales from the piping system and the boiler to maintain the power generation efficiency. In the current thermal plant treated by All Volatile Treatment (AVT) the iron elutes to the feed water in the low-temperature part which changes into iron ion or the paramagnetic fine iron oxide particles. On the other hand at the high-temperature part the main component of the scales is large ferromagnetic particles of magnetite. Therefore the magnetic separation at the high-temperature part is the more effective to remove the scale than that at the low-temperature part. For the reason, the existing method using the electromagnetic filter placed in the low-temperature part is not effective to remove the scales. We studied the high gradient magnetic separation (HGMS) at high-temperature part to remove a large amount of the scale. In this study, we assumed to install the HGMS system using the superconducting magnet at the inlet of the boiler.

Simultaneous deceleration of atoms and molecules in a supersonic beam

A unique property of Zeeman effect based manipulation of paramagnetic particle’s motion is the ability to control velocities of both atoms and molecules. In particular the moving magnetic trap decelerator is capable of slowing and eventually trapping mixtures of both cold atoms and cold molecules generated in a supersonic expansion. Here we report the deceleration of molecular oxygen together with metastable argon atoms. The cold mixture with temperature below 1 K is slowed from an initial velocity of 430 m s−1 down to 100 m s−1. Our decelerator spans 2.4 m and consists of 480 quadrupole traps. Our results pave the way for the study of sympathetic cooling of molecules by laser cooled atoms.

Observation of microwave superfluid phenomena of multiple phase magnetic fluid

We observe superfluid phenomena by microwaves irradiation to multiple phase magnetic fluid in room temperature or room pressure. Ferromagnetism transformation of diamagnetic or paramagnetic particles in multiple phase magnetic fluid containing constant rate of ferromagnetic particles, diamagnetic or paramagnetic particles mixing organic polyphenol and irradiation of microwaves is, observed by superexchange interaction. Superfluid phenomena are observed by irradiation of microwaves to aforementioned multiple phase of magnetic fluid containing ferromagnetism transformed diamagnetic or paramagnetic particles with ferromagnetic particles. Mixing semiconductor pigments amplifying superfluid energy by photosensitivity is observed. Visible light LED selecting wavelength is irradiated to superfluid condition of aforementioned multiple phase magnetic fluid thus magnetic field and energy of superfluid is enhanced by light quantum amplification effect.

Nanoparticle enhanced MRI scanning to detect cellular inflammation in experimental chronic renal allograft rejection.

Objectives. We investigated whether ultrasmall paramagnetic particles of iron oxide- (USPIO-) enhanced magnetic resonance imaging (MRI) can detect experimental chronic allograft damage in a murine renal allograft model. Materials and Methods. Two cohorts of mice underwent renal transplantation with either a syngeneic isograft or allograft kidney. MRI scanning was performed prior to and 48 hours after USPIO infusion using T2∗-weighted protocols. R2∗ values were calculated to indicate the degree of USPIO uptake. Native kidneys and skeletal muscle were imaged as reference tissues and renal explants analysed by histology and electron microscopy. Results. R2∗ values in the allograft group were higher compared to the isograft group when indexed to native kidney (median 1.24 (interquartile range: 1.12 to 1.36) versus 0.96 (0.92 to 1.04), P < 0.01). R2∗ values were also higher in the allograft transplant when indexed to skeletal muscle (6.24 (5.63 to 13.51)) compared to native kidney (2.91 (1.11 to 6.46) P < 0.05). Increased R2∗ signal in kidney allograft was associated with macrophage and iron staining on histology. USPIO were identified within tissue resident macrophages on electron microscopy. Conclusion. USPIO-enhanced MRI identifies macrophage.

Manipulating archaeal systems to permit analyses of transcription elongation-termination decisions in vitro.

Transcription elongation by multisubunit RNA polymerases (RNAPs) is processive, but neither uniform nor continuous. Regulatory events during elongation include pausing, backtracking, arrest, and transcription termination, and it is critical to determine whether the absence of continued synthesis is transient or permanent. Here we describe mechanisms to generate large quantities of stable archaeal elongation complexes on a solid support to permit (1) single-round transcription, (2) walking of RNAP to any defined template position, and (3) discrimination of transcripts that are associated with RNAP from those that are released to solution. This methodology is based on untagged proteins transcribing biotin- and digoxigenin-labeled DNA templates in association with paramagnetic particles.

Manipulation with Magnetic Tweezers of Mechanosensitive Ion Channels and Adaptation Motors in Hair Cells of the Inner Ear

Hair cells, ubiquitously found in the auditory and vestibular systems of vertebrates, transduce mechanical stimuli into electrical responses. The apical surface of each cell sports a hair bundle composed of numerous actin-filled stereocilia. Mechanical stimulation deflects the hair bundle and tenses filamentous cadherin tetramers called tip links that interconnect adjacent stereocilia. Tensing of the tip links is thought to open mechanosensitive ion channels to which the links are connected, leading to depolarization of the hair cell and the subsequent firing of afferent nerve fibers. A motor containing myosin 1c molecules readjusts the tension in the tip links, allowing transduction to adapt during sustained deflections. Because the channels and motors lie deep within the hair bundle, the direct experimental manipulation of the individual components has been challenging: experiments have heretofore been limited to deflections of entire hair bundles. We have devised a scheme for labeling tip links from the sacculus of the bullfrog's inner ear with paramagnetic particles through an epitope-specific anti-cadherin antibody and a long DNA tether. By measuring the potential difference across the tissue, we show that application of a magnetic field elicits inward transduction current_a result that directly confirms the hypothesis that tension in the tip links gates the mechanically sensitive channels. Future experiments that track the position of the magnetic particle may demonstrate the opening and closing of transduction channels and the climbing and slipping of adaptation motors.

Paramagnetic, pH and temperature-sensitive polymeric particles for anticancer drug delivery and brain tumor magnetic resonance imaging

Dually responsive polymeric particles for brain tumor (glioma) MR imaging and anticancer drug delivery.

Hydrodynamic instability in a magnetically driven suspension of paramagnetic red blood cells.

We investigate the magnetically driven motion in suspensions of paramagnetic particles. Our object is diluted deoxygenated whole blood with paramagnetic red blood cells (RBCs). We use direct observations in a closed vertical Hele-Shaw channel, and a well-defined magnetic force field applied horizontally in the channel plane. At very low cell concentrations, we register single-particle motion mode, track individual cells and determine their hydrodynamic and magnetic characteristics. Above 0.2 volume percent concentration, we observe local swirls and a global transient quasi-periodic vortex structure, intensifying with increasing cell concentration, but surprisingly this does not influence the time and purity of the magnetic extraction of RBCs. Our observations shed light on the behavioral complexity of magnetically driven submagnetic suspensions, an important issue for the emerging microfluidic technology of direct magnetic cell separation and intriguing for the mechanics of particulate soft matter.

Microchip capillary electrophoresis: quantum dots and paramagnetic particles for bacteria immunoseparation: rapid superparamagnetic-beads-based automated immunoseparation of Zn-Proteins from Staphylococcus aureus with nanogram yield.

The emergence of drug-resistant bacteria and new or changing infectious pathogens is an important public health problem as well as a serious socioeconomic concern. Immunomagnetic separation-based methods create new possibilities for rapidly recognizing many of these pathogens. Nanomaterial-based techniques including fluorescent labeling by quantum dots as well as immunoextraction by magnetic particles are excellent tools for such purposes. Moreover, the combination with capillary electrophoresis in miniaturized microchip arrangement brings numerous benefits such as fast and rapid analysis, low sample consumption, very sensitive electrochemical and fluorescent detection, portable miniaturized instrumentation, and rapid and inexpensive device fabrication. Here the use of superparamagnetic particle-based fully automated instrumentation to isolate pathogen Staphylococcus aureus and its Zn(II)-containing proteins (Zn-proteins) is reported using a robotic pipetting system speeding up the sample preparation and enabling to analyze 48 real samples within 6 h. Cell lysis and Zn-protein extractions were obtained from a minimum of 100 cells with the sufficient yield for SDS-PAGE (several tens ng of proteins).

EPR Spectroscopy of catalytic systems based on nickel complexes of 1,4-diaza-1,3-butadiene (α-diimine) ligands in hydrogenation and polymerization reactions

EPR spectroscopy is used to study catalytic hydration and polymerization reaction systems based on α-diimine complexes of Ni(0) and Ni(II) with the general formula NiBr2(DAD–R) (R = –C3H7 or –CH3) or Ni(DAD–CH3)2 (DAD(–C3H7) = 1,4-bis(2,6-diiso-propylphenyl)-2,3-(dimethyl-1,4-diazabuta-1,3-diene, DAD(–CH3) = 1,4-bis(2,6-dimethylphenyl)-2,3-dimethyl-1,4-diazabuta-1,3-diene)), in combination with Lewis acids (AlEt3, AlEt2Cl, AlEtCl2, B(F5C6)3, BF3·OEt2). Ni(I) complexes of the form (DAD–R)NiX2AlX′y(C2H5)3–y composition (an aluminum atom can be replaced by a boron atom) were identified, where R = –CH3 or –C3H7, X = Br, and X′ = Cl or –C2H5 and α-diimine anion radicals are included in derivatives of aluminum or boron. Oxidation reactions of the Ni(DAD–CH3)2 complex with aluminum alkyl halides and boron derivatives with formation of paramagnetic nickel complexes are observed. It is found that there is no direct relationship between the polymerization activity of ethylene or hydration of the alkenes and the concentration of paramagnetic particles.

Нарушения в системе цитокинов при остром герпетическом стоматите у детей = Violations in the system of cytokines at the acute herpetic stomatitis of children

Violations of the immune system is relevant contemplation in particular features of the synthesis of IL-12 and cytokines which influenced on its products, considering enough widespread acute herpetic child’s stomatitis which have recurrent course. The aim of research is explore the features of production of IL-12 on the children with acute herpetic stomatitis, and to identify the factors that influenced on this indicator. Materials and methods. At the research were involved 71 children with acute herpetic stomatitis (AHS), at the age of 3 years. All the children are divided on two groups. The first group was consisted of 37 children with rather heavy AHS. The second group comprised of 34 children with heavy AHS.For determination of the level of cytokines laser flow cytometry with using paramagnetic particles was applied. Investigations were carried out on the flow cytofluorometry laser FACS Calibrum™ System (manufacturer Bectom Dickinson), using a test system manufacturer. Results and conclusions. A low level of IL-12 were observed at 3 years children with acute herpetic stomatitis. Violation of pro- and anti-inflammatory cytokines production was established. These changes bring the decreasing of anti-infectious defense and the progress of infection.

Landscape-inversion phase transition in dipolar colloids: tuning the structure and dynamics of 2D crystals.

We study the 2D crystalline phases of paramagnetic colloidal particles with dipolar interactions and constrained on a periodic substrate. Combining theory, simulation, and experiments, we demonstrate a new scenario of first-order phase transitions that occurs via a complete inversion of the energy landscape, featuring nonconventional properties that allow for (i)tuning of crystal symmetry, (ii)control of dynamical properties of different crystalline orders via tuning of their relative stability with an external magnetic field, (iii)an equivalent but independent control of the same dynamic properties via temporal modulations of that field, and (iv)nonstandard phase-ordering kinetics involving spontaneous formation of transient metastable domains.

Paramagnetic cellulose DNA isolation improves DNA yield and quality among diverse plant taxa.

• Premise of the study: The chemical diversity of land plants ensures that no single DNA isolation method results in high yield and purity with little effort for all species. Here we evaluate a new technique originally developed for forensic science, based on MagnaCel paramagnetic cellulose particles (PMC), to determine its efficacy in extracting DNA from 25 plant species representing 21 families and 15 orders.• Methods and Results: Yield and purity of DNA isolated by PMC, DNeasy Plant Mini Kit (silica column), and cetyltrimethylammonium bromide (CTAB) methods were compared among four individuals for each of 25 plant species. PMC gave a twofold advantage in average yield, and the relative advantage of the PMC method was greatest for samples with the lowest DNA yields. PMC also produced more consistent sample purity based on absorbance ratios at 260:280 and 260:230 nm.• Conclusions: PMC technology is a promising alternative for plant DNA isolation.