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Electrical Charge (electrical + charge)

Distribution by Scientific Domains
Life Sciences28%
Chemistry28%

Selected Abstracts

Capillary electrophoresis using copolymers of different composition as physical coatings: A comparative study

ELECTROPHORESIS, Issue 5-6 2006
Guillaume L. Erny
Abstract In this work, a comparative study on the use of different polymers as physically adsorbed coatings for CE is presented. It is demonstrated that the use of ad hoc synthesized polymers as coatings allows tailoring the EOF in CE increasing the flexibility of this analytical technique. Namely, different polymers were synthesized at our laboratory using different percentages of ethylpyrrolidine methacrylate (EpyM) and N,N -dimethylacrylamide (DMA). Thus, by modifying the percentage of EpyM and DMA monomers it is possible to manipulate the positive charge of the copolymer, varying the global electrical charge on the capillary wall and with that the EOF. These coated capillaries are obtained by simply flushing a given EpyM,DMA aqueous solution into bare silica capillaries. It is shown that by using these coated capillaries at adequate pHs, faster or more resolved CE separations can be achieved depending on the requirements of each analysis. Moreover, it is demonstrated that these coated capillaries reduce the electrostatic adsorption of basic proteins onto the capillary wall. Furthermore, EpyM,DMA coatings allow the reproducible chiral separation of enantiomers through the partial filling technique (PFT). The EpyM,DMA coated capillaries are demonstrated to provide reproducible EOF values independently of the pH and polymer composition with%RSD values lower than 2% for the same day. It is also demonstrated that the coating procedure is reproducible between capillaries. The compatibility of this coating protocol with CE in microchips is discussed. [source]

Treatment of low turbidity water by sweep coagulation using bentonite

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2005
Yun-Hwei Shen
Abstract A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na+ -saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm,3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face-to-face interactions of platelets and effectively entrapped TiO2 particles in band-type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO2 particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry [source]

Design of Nano-Laminated Coatings to Control Bioavailability of Lipophilic Food Components

JOURNAL OF FOOD SCIENCE, Issue 1 2010
David Julian McClements
ABSTRACT:, There is currently a lack of effective delivery systems to encapsulate, protect, and release bioactive lipophilic components, such as ,-3 fatty acids, conjugated linoleic acid, tributyrin, vitamins, antioxidants, carotenoids, and phytosterols, which is holding back the development of functional foods designed to combat diseases such as coronary heart disease, diabetes, hypertension, and cancer. Delivery systems consisting of lipid droplets encapsulated by nano-laminated biopolymer coatings have great potential for use in the food industry for the encapsulation, protection, and release of bioactive lipids. This article reviews the potential impact of the physicochemical characteristics of nano-laminated biopolymer coatings on the bioavailability of encapsulated lipids. The effects of layer thickness, composition, electrical charge, permeability, and environmental responsiveness on digestion, release, and absorption of lipophilic components are highlighted. The possibility of designing nano-laminated biopolymer coatings to increase, decrease, or control the bioavailability of encapsulated lipids is shown. Data generated from,in vitro,digestion models and animal feeding studies are presented. This knowledge could be used by the food industry to produce functional foods designed to improve human health and wellness. [source]

Mimosa pudica: Electrical and mechanical stimulation of plant movements

PLANT CELL & ENVIRONMENT, Issue 2 2010
ALEXANDER G. VOLKOV
ABSTRACT Thigmonastic movements in the sensitive plant Mimosa pudica L., associated with fast responses to environmental stimuli, appear to be regulated through electrical and chemical signal transductions. The thigmonastic responses of M. pudica can be considered in three stages: stimulus perception, electrical signal transmission and induction of mechanical, hydrodynamical and biochemical responses. We investigated the mechanical movements of the pinnae and petioles in M. pudica induced by the electrical stimulation of a pulvinus, petiole, secondary pulvinus or pinna by a low electrical voltage and charge. The threshold value was 1.3,1.5 V of applied voltage and 2 to 10 µC of charge for the closing of the pinnules. Both voltage and electrical charge are responsible for the electro-stimulated closing of a leaf. The mechanism behind closing the leaf in M. pudica is discussed. The hydroelastic curvature mechanism closely describes the kinetics of M. pudica leaf movements. [source]

Enhanced Bone Bonding of the Hydroxyapatite/,-Tricalcium Phosphate Composite by Electrical Polarization in Rabbit Long Bone

ARTIFICIAL ORGANS, Issue 6 2010
Hideki Sagawa
Abstract A review of the osteogenic cell activity and new bone growth in the regions bordering negatively charged surfaces of polarized Hydroxyapatite/,-tricalcium phosphate (HA/TCP) composites implanted in the long bone in rabbits was conducted. Polarized and non-polarized HA/TCP specimens were implanted into the right and left femoral condyle, respectively (each n = 10). After 3 and 6 weeks, five rabbits were sacrificed in each group, and histological analysis was administered. Large cuboidal-shaped osteoblastic cells were predominantly observed lining the newly formed bone on the negatively charged surface (N-surface) in the polarized HA/TCP implants. The TRAP-positive multinucleated cells were observed extensively in the newly formed bone on the N-surfaces compared with the 0-surface and adhered directly to the HA/TCP composite. The bone area (B.Ar) value, newly formed bone area contacting the implant, and contact length (C.Le) value, percentage length of newly formed bone directly attaching to the implant, on both the 0- and N-surface increased significantly with time in each group. Both the B.Ar and C.Le value on the N-surface were significantly greater than those on the 0-surface after 3 and 6 weeks. The number of TRAP-positive cells/total length value on the N-surface was significantly greater than that on the 0-surface after 3 and 6 weeks postoperatively. It is hypothesized that electrical charge acquired by electrical polarization treatment may modify the biochemical and biophysical processes of the osteogenic cells, resulting in enhanced new bone formation and direct bonding between the recipient bone and implants. [source]

Temperature-dependent pseudopotential between two pointlike electrical charges

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-6 2003
M.-M. Gombert
Abstract The pair distribution functions for particles electrically charged, at a temperature T, expressed in terms of density matrices and the corresponding pseudopotentials are studied. For an electron pair, the symmetry of the wave functions is taken into account. Exact expansions with respect to the separation distance and to a quantum parameter (, T,½) are carried out. The known results are recovered. For high temperature, accurate approximations are derived. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magnonics: Spin Waves on the Nanoscale

ADVANCED MATERIALS, Issue 28 2009
Sebastian Neusser
Abstract Magnetic nanostructures have long been in the focus of intense research in the magnetic storage industry. For data storage the nonvolatility of magnetic states is of utmost relevance. As information technology generates the need for higher and higher data-transfer rates, research efforts have moved to understand magnetization dynamics. Here, spin waves and their particle-like analog, magnons, are increasingly attracting interest. High-quality nanopatterned magnetic media now offer new ways to transmit and process information without moving electrical charges. This new functionality is enabled by spin waves. They are confined by novel functioning principles, which render them especially suitable to operate at the nanoscale. Magnonic crystals are expected to provide full control of spin waves, similarly to what photonic crystals already do for light. Combined with nonvolatility, multifunctional metamaterials might be formed. We report recent advances in this rapidly increasing research field called magnonics. [source]