15 results match your criteria biconcave carbon

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A "Biconcave-Alleviated" Strategy to Construct -Derived Carbon/MoS for Ultrastable Sodium Ion Storage.

ACS Nano 2021 Aug 11. Epub 2021 Aug 11.

State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.

Two-dimensional layered materials commonly face hindered electron transfer and poor structure stability, thus limiting their application in high-rate and long-term sodium ion batteries. In the current study, we adopt finite element simulation to guide the rational design of nanostructures. By calculating the von Mises stress distribution of a series of carbon materials, we find that the hollow biconcave structure could effectively alleviate the stress concentration resulting from expansion. Read More

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Biconcave Carbon Nanodisks for Enhanced Drug Accumulation and Chemo-Photothermal Tumor Therapy.

Adv Healthc Mater 2019 04 11;8(8):e1801505. Epub 2019 Mar 11.

Department of Materials Science and Engineering, University of Washington, Seattle, Washington, DC, 98195, USA.

It is considered a significant challenge to construct nanocarriers that have high drug loading capacity and can overcome physiological barriers to deliver efficacious amounts of drugs to solid tumors. Here, the development of a safe, biconcave carbon nanodisk to address this challenge for treating breast cancer is reported. The nanodisk demonstrates fluorescent imaging capability, an exceedingly high loading capacity (947. Read More

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Bio-field array: a dielectrophoretic electromagnetic toroidal excitation to restore and maintain the golden ratio in human erythrocytes.

Physiol Rep 2018 06;6(11):e13722

The Loewenberg College of Nursing, University of Memphis, Memphis, Tennessee.

Erythrocytes must maintain a biconcave discoid shape in order to efficiently deliver oxygen (O ) molecules and to recycle carbon dioxide (CO ) molecules. The erythrocyte is a small toroidal dielectrophoretic (DEP) electromagnetic field (EMF) driven cell that maintains its zeta potential (ζ) with a dielectric constant (ԑ) between a negatively charged plasma membrane surface and the positively charged adjacent Stern layer. Here, we propose that zeta potential is also driven by both ferroelectric influences (chloride ion) and ferromagnetic influences (serum iron driven). Read More

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π-π stacking between polyaromatic hydrocarbon sheets beyond dispersion interactions.

Phys Chem Chem Phys 2016 Aug;18(32):22300-10

Department of Chemistry and Biochemistry, Texas Tech University, Lubbock Texas 79409, USA. and School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin, 300072 P. R. China and Institute for Soil Research, University of Natural Resources and Life Sciences Vienna, A-1190 Vienna, Austria.

High level ab initio calculations ranging from coupled cluster methods including explicitly correlated approaches to standard second order Møller-Plesset theory using spin scaling (SOS-MP2) have been performed on sandwich and slipped parallel dimer structures of a series of quasi one-dimensional acenes and on two-dimensional sheets containing the pyrene to coronene series encircled with two layers of benzene rings. Sandwich (graphitic AA type) and slipped parallel (AB type) structures were considered and, within the given symmetry restrictions, full geometry optimizations were performed. Basis set superposition effects have been considered. Read More

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Shape-directed compartmentalized delivery of a nanoparticle-conjugated small-molecule activator of an epigenetic enzyme in the brain.

J Control Release 2015 Nov 29;217:151-9. Epub 2015 Aug 29.

Nanomaterials and Catalysis Laboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O, Bangalore 560 064, India. Electronic address:

Targeted drug delivery to specific subcellular compartments of brain cells is challenging despite their importance in the treatment of several brain-related diseases. Herein, we report on shape-directed intracellular compartmentalization of nanoparticles in brain cells and their ability to deliver therapeutic molecules to specific organelles. Iron oxide (Fe3O4) nanoparticles with different morphologies (spheres, spindles, biconcaves, and nanotubes) were synthesized and coated with a fluorescent carbon layer derived from glucose ([email protected]). Read More

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November 2015

Rh proteins vs Amt proteins: an organismal and phylogenetic perspective on CO2 and NH3 gas channels.

Authors:
J Peng C H Huang

Transfus Clin Biol 2006 Mar-Apr;13(1-2):85-94. Epub 2006 Mar 27.

Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10021, USA.

Rh (Rhesus) proteins are homologues of ammonium transport (Amt) proteins. Physiological and structural evidence shows that Amt proteins are gas channels for NH(3), but the substrate of Rh proteins, be it CO2 as shown in green alga, or NH3/NH4+ as shown in mammalian cells, remains disputed. We assembled a large dataset generated of Rh and Amt to explore how Rh originated from and evolved independently of Amt relatives. Read More

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September 2006

Metal complexes of a biconcave porphyrin with D4-structure--versatile chiral shift agents.

Chemistry 2001 Jun;7(12):2676-86

Institut für Organische Chemie, Universität Innsbruck, Austria.

Representative metal complexes of a biconcave D4-symmetric porphyrin were synthesised by metalion insertion into the porphyrin ligand 1. The NMR spectra suggested D4-symmetry for the ZnII and dioxo-RuVI complexes of 1 and C4-symmetry for the unsymmetrically ligated RuII and RhIII complexes. Metal complexes of 1 proved to be versatile chiral 1H NMR shift agents for a broad spectrum of organic amines, alcohols, carboxylic acids, esters, nitriles and nonpolar fullerene derivatives. Read More

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Effective bilayer expansion and erythrocyte shape change induced by monopalmitoyl phosphatidylcholine. Quantitative light microscopy and nuclear magnetic resonance spectroscopy measurements.

Authors:
L M Chi W G Wu

Biophys J 1990 Jun;57(6):1225-32

Institute of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.

When human erythrocytes are treated with exogenous monopalmitoyl phosphatidylcholine (MPPC), the normal biconcave disk shape red blood cells (RBC) become spiculate echinocytes. The present study examines the quantitative aspect of the relationship between effective bilayer expansion and erythrocyte shape change by a newly developed method. This method is based on the combination of direct surface area measurement of micropipette and relative bilayer expansion measurement of 13C crosspolarization/magic angle spinning nuclear magnetic resonance (NMR). Read More

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Electron microscopic studies of the intracellular polymerization of sickle hemoglobin.

Blood Cells 1988 ;13(3):359-76

Laboratory of Chemical Biology, National Institute of Diabetes, and Digestive and Kidney Diseases, Bethesda, Maryland 20892.

Transmission electron microscopy has been used to study intracellular sickle hemoglobin polymer in unfractionated cells from the arterial and venous blood of patients and after external deoxygenation. We detect polymerized hemoglobin in up to 10% of the cells in the venous circulation, especially in cells that are "cigar-shaped" and appear to be irreversibly sickled. We could not see well-defined polymer in mixed arterial samples; nevertheless, we found electron opaque spots, which could be ferritin granules, hemosiderin, or small aggregates of hemoglobin S. Read More

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Hemolysis and morphological changes in rat erythrocytes with mercurials.

Authors:
R Tanaka K Nakai

Jpn J Pharmacol 1977 Jun;27(3):413-9

Effects of mercurials on rat erythrocytes were studied morphologically using an electron microscope. In the scanning study, the normal biconcave shape of the erythrocytes was changed to rugged surface spherocytes when mercuric chloride was added to the erythrocyte suspension. Methylmercuric chloride produced an irregularity of cell shape with spicules including the final stage of spherocytes. Read More

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Studies on preparation technique of human erythrocytes for clinical scanning electron microscopy.

Authors:
S F Al-Samarrai

Arch Histol Jpn 1975 Nov;38(4):321-34

Various methods of preparation were tested and modified in order to establish a proper method of preparing normal and pathological human erythrocytes for scanning electron microscopy. Morphological changes after various preparation techniques, such as echinocytosis, spherocytosis, elliptocytosis and knizocytosis were studied and evaluated statistically. The best method, so far obtained to preserve 99% of normal erythrocytes as biconcave discocytes, was that of venous blood without anticoagulants or acid-citrate-dextrose, washed with physiological saline at 37 degrees C, fixed in 0. Read More

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November 1975

Role of the red cell membrane in oxygen uptake.

Authors:
H Kutchai

Respir Physiol 1975 Jan;23(1):121-32

The rate at which red blood cells take up O2 or CO as measured in a rapid reaction apparatus is considerably less than predicted from solution of the equations for diffusion and chemical reaction in a layer of hemoglobin solution about the same thickness as the red cell. Nicolson and Roughton (1951) showed that this discrepancy could be accounted for by postulating that the red cell membrane is an important barrier to gas uptake. Sinha (1969) measured the rate of O2 uptake by single red cells located near a gas-plasma interface. Read More

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January 1975

The rate of uptake of carbon monoxide and of nitric oxide by normal human erythrocytes and experimentally produced spherocytes.

J Gen Physiol 1958 Sep;42(1):83-107

THE UPTAKE OF GASES SUCH AS OXYGEN, CARBON MONOXIDE, OR NITRIC OXIDE BY THE ERYTHROCYTE INVOLVES: (a) diffusion across the cellular membrane, (b) intraerythrocytic diffusion, and (c) chemical combination with hemoglobin. The aim of this investigation was to obtain data which would permit an analysis of each of these factors in limiting the rate of gas uptake. The initial over-all rate of uptake of gases which combine chemically with hemoglobin to produce a color change can be measured by a modified version of the Hartridge-Roughton-Millikan constant flow, rapid reaction apparatus. Read More

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September 1958

The effects of sickling on ion transport. I. Effect of sickling on potassium transport.

J Gen Physiol 1955 Sep;39(1):31-53

The conversion of red cells of patients with sickle cell anemia (S-S) from biconcave disk to sickle shape by removal of oxygen was found to increase the fraction of medium trapped in cells packed by centrifugation from 0.036 (S.E. Read More

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September 1955
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