Search Results - (Author, Cooperation:C. Shang)

2018-02-28

Genetics Society of America (GSA)

0016-6731

Biology

2018-02-06

Institute of Physics (IOP)

1367-2630

Physics

2015-06-27

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Amygdala/physiology ; Animals ; Conditioning, Classical ; Fear/*physiology ; Female ; Male ; Memory/*physiology ; Mice ; Neurons/chemistry/*physiology ; Parvalbumins/analysis/*metabolism ; Superior Colliculi/cytology/*physiology ; Visual Pathways/*physiology

2018-11-22

American Physical Society (APS)

1098-0121

1095-3795

Physics

Superfluidity and superconductivity

2018-12-06

Institute of Physics (IOP)

1367-2630

Physics

2014-08-15

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Cardiac Myosins/genetics ; Cardiomegaly/*genetics/*pathology/prevention & control ; Cardiomyopathies/genetics/pathology/prevention & control ; Chromatin/genetics/metabolism ; Chromatin Assembly and Disassembly ; DNA Helicases/antagonists & inhibitors/chemistry/genetics/metabolism ; Feedback, Physiological ; Heart Failure/genetics/pathology/prevention & control ; Histone Deacetylases/metabolism ; Humans ; Mice ; Myocardium/metabolism/pathology ; Myosin Heavy Chains/*genetics ; Nuclear Proteins/antagonists & inhibitors/chemistry/genetics/metabolism ; Organ Specificity ; Poly(ADP-ribose) Polymerases/metabolism ; Protein Binding ; Protein Structure, Tertiary ; RNA, Long Noncoding/antagonists & inhibitors/*genetics/metabolism ; Transcription Factors/antagonists & inhibitors/chemistry/genetics/metabolism

2018-09-26

American Physical Society (APS)

1539-3755

1550-2376

Physics

Plasma Physics

1089-7550

AIP Digital Archive

Physics

A new type of domain structure observed in the annealed Bi/Al/Mn/SiO films is described. The domain is embedded into a round colony called dense branching morphology. Increasing ramified branches and conspicuous circular envelopes are two distinguished features of the colony. Magnetic measurement indicated that the branches of different contrasts were relevant to the different magnetization orientations in the films. It was also revealed that the Kerr rotation topography in high spatial resolution could exactly match the branch geometry on the morphology. Composition analyses showed that intensive diffusion and segregation of Bi atoms during the thermal annealing contributed a lot to the formation of the domain structure.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The effects of doping Cu, Al, and Ag in Pt spacer layers on the perpendicular anisotropy Ku and the polar Kerr rotation aitch-thetak in the wavelength range of 400–800 nm have been investigated for sputtered 0.8 nm Pt/0.3 nm Co multilayers. Ku and aitch-thetak measured below 633 nm decrease with the increase of the concentrations of Cu, Al, and Ag in the Pt spacer layers. It is found that the variation of Ku and aitch-thetak with the doping concentrations follows a quadratic equation of Ku=aaitch-theta2k+b (a, b are constants here). This suggests that both Ku and aitch-thetak originate from a common micromechanism, i.e., spin-orbit coupling. An obvious enhancement in the peak of the polar Kerr rotation appears at 770 nm for Cu and Ag dopings and at 680 nm for Al doping. Moreover, the polar Kerr rotation aitch-thetak* at this enhanced peak shows an oscillation behavior with the increasing doping concentrations in the Pt spacer layers. © 1996 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The effects of doping Ni into the Pt spacer layer on the polar Kerr rotation θk and perpendicular anisotropy Ku of the sputtered Pt/Co multilayers have been investigated. A similar tendency of the variations of Ku and θk with the doping concentration of Ni specifies that they arise from the same source, the spin-orbit coupling. An enhanced magneto-optical effect appears in Pt1−xNix/Co multilayers at x=0.08 and can be attributed to variation of the off-diagonal elements of the conductivity tensor. © 1997 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

MnBiAl films were prepared by vacuum interdiffusion alloying. We report on the magneto-optical properties and low temperature magnetization of this material. By eliminating the Faraday contribution from the glass substrates, a remanant Kerr rotation of 3.22° at 632.8 nm is measured at room temperature. At a wavelength of 376 nm, the remanent Kerr rotation is 2.25°. Superconducting quantum interference device magnetometer examination showed that there is no spin transition at low temperature for the MnBiAl films. By decreasing the temperature from 280 to 5 K, the perpendicular remanant magnetization of the MnBi0.47Al0.15 films remains along the c axis and increases about 12% in magnitude, while MnBi changes its easy axis from the c axis to the base plane at around 84 K. This suggests that both the lattice shrinkage and chemical interactions among Mn, Bi, and Al atoms play important roles in the magnetic properties of MnBi0.47Al0.15 alloy films. © 1997 American Institute of Physics.

Electronic Resource

0305-0491

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

1436-5073

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Zusammenfassung Ein gaschromatographisches Verfahren für die Mikrobestimmung von Carboxylgruppen durch Decarboxylierung wurde beschrieben. Die Probe wird in Gegenwart von Chinolin und Kupfer(II)-carbonat in einem geschlossenen Gefäß erhitzt. Das freigesetzte Kohlendioxid wird in einen Gaschromatographen geleitet. Die Höhe der Zacken des Chromatogrammes entspricht der Menge an Carbonsäure in der Probe. Die Methode ist rasch, einfach und genau.

Résumé On décrit un procédé chromatographique en phase gazeuse pour le microdosage des groupes carboxyliques par décarboxylation. On chauffe l'échantillon avec de la quinoléine et du carbonate de cuivre-II, dans un récipient fermé et l'on fait arriver le gaz carbonique qui se forme, dans l'appareil de chromatographie en phase gazeuse. La hauteur du pic sur le chromatogramme varie linéairement avec la quantité d'acide carboxylique de l'échantillon. La méthode est rapide, simple et précise.

Summary A gas-chromatographic procedure for the microdetermination of carboxyl groups by decarboxylation is described. The sample is heated in the presence of quinoline and cupric carbonate in a closed vessel; the carbon dioxide formed is then driven into the gas chromatograph. The peak-height on the chromatogram varies linearly with the amount of carboxylic acid in the sample. The method is rapid, simple, and accurate.

Electronic Resource

1432-184X

Springer Online Journal Archives 1860-2000

Biology

Abstract A nonreductive community-level study of P availability was conducted using various forms of adsorbed P. Orthophosphate (Pi), inositol hexaphosphate (IHP), and glucose 6-phosphate (G6P) were adsorbed to a short-range ordered Al precipitate. These bound phosphates provided a P source sufficient to support the growth of microbial communities from acidic Brazilian soils (oxisols). Adsorbed IHP, the most abundant form of organic phosphate in most soils, had the lowest bioavailability among the three phosphates studied. Adsorbed G6P and Pi were almost equally available. The amount of adsorbed Pi (1 cmol P kg−1) required to support microbial growth was at least 30 times less than that of IHP (30 cmol P kg−1). With increased surface coverage, adsorbed IHP became more bioavailable. This availability was attributed to a change in the structure of surface complexes and presumably resulted from the decreased number of high-affinity surface sites remaining at high levels of coverage. It thus appears that the bioavailability of various forms of adsorbed phosphate was determined primarily by the stability of the phosphate-surface complexes that they formed, rather than by the total amount of phosphate adsorbed. IHP, having the potential to form stable multiple-ring complexes, had the highest surface affinity and the lowest bioavailability. Bioaggregates consisting of bacteria and Al precipitate were observed and may be necessary for effective release of adsorbed P. Bacteria in the genera Enterobacter and Pseudomonas were the predominate organisms selected during these P-limited enrichments.

Electronic Resource

1573-4919

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Medicine

Summary Surfactants, which provide a hydrophobic environment, may induce an ordered conformation in polypeptides and proteins that contain a sequence with helix- or β-forming potential. This hypothesis has been illustrated in circular dichroic studies of oligopeptides and short polypeptides. These peptide-surfactant complexes can form (1) a helix, (2) a β-form, (3) either form (depending on experimental conditions), or can remain in (4) an ordered form. The induced helix is stable in a surfactant solution below or above its critical micellar concentration, whereas the induced β-form is usually converted back to an unordered form when the surfactant used is above its critical micellar concentration, or it is transformed into a helix in excess surfactant solution if the peptide has both the helix- and β-forming potential. In most cases the observed conformations agree with those predicted from the amino acid sequences of the peptides. The induced conformation of a peptide can be destabilized by charges on the side groups having the same sign as that of surfactant ions. Disulfide bonds can inhibit the formation of induced conformation because of steric hindrance. The terminal effect can prevent a peptide from forming an ordered conformation near the NH2- and COOH-terminus.

Electronic Resource

1573-4943

β-sheet ; circular dichroism ; concanavalin A ; conformation

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract The conformations of concanavalin A (con A), an all-β protein, and its three CNBr-cleaved fragments were studied by CD. Con A in buffer showed a 197 nm maximum and a 223 nm minimum, which were red-shifted by 6–7 nm from those of regular all-β proteins and β-sheet of (Lys) n . Fragment 1 (residue 1–42) resembled an unordered form with a CD maximum at 200 nm, but fragments 2 (residues 43–129) and 3 (residues 130–237) showed a regular CD spectrum with two extrema at 192–193 nm (+) and 214–216 nm (−). Equimolar mixture of the three fragments showed some degree of interaction, but did not reconstitute the conformation of native con A, probably because of the loss of bound Ca2+ and Mn2+ ions in the fragments. In ethanol-, methanol-, and dioxane-water mixed solvents, con A and its fragments remained as β-sheet. In contrast, addition of trifluoroethanol and sodium dodecyl sulfate induceda-helix at the expense of β-sheet for con A and its fragments in aqueous solution. In 80% trifluoroethanol, the induced helicities exceeded their sequence-predicted helix-potentials, but in 10 mM sodium dodecyl sulfate the helicities agreed well with corresponding predictions.

Electronic Resource

1573-4943

Opioid-binding proteins ; conformation ; circular dichroism ; sequence-predictive method

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract Based on circular dichroism (CD) and the sequence-predictive method, the opioid-binding cell adhesion molecule (OBCAM) consisted of one half β-sheets and one fourth α-helices. This is consistent with significant sequence homology of the protein to several members of the immunoglobulin (Ig) superfamily, particularly cell adhesion molecules, which are rich in β-sheets. Hydropathy analysis suggests that hydrophobic and hydrophilic regions were evenly distributed along the sequence, but the NH2- and COOH-termini were hydrophobic. Hydrophobic moments and Fourier-transform amphipathic analyses further suggest that residues 23–30 and 83–93 were amphiphathie β-sheets. The overall conformation of OBCAM was unaltered by adding linoleic acid, which is required for opioid ligand binding.

Electronic Resource

1573-4943

Acetylcholine receptor ; circular dichroism ; conformation ; agonists ; antagonists

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract The conformations of acetylcholine receptor fromTorpedo californica in the absence and presence of agonists, antagonists, and local anesthetics were studied by circular dichroism (CD). Without ligands, the receptor had about 40% helix, 20% β-sheets, and 10% β-turns as analyzed from its far-UV CD spectrum. Its near-UV CD spectrum resembled that of acetylcholinesterase from the same source. None of the ligands studied altered the far-UV spectrum of the receptor. However, in the near-UV region, carbamylcholine and acetylcholine shifted the Phe and Tyr bands of AChR to less negative, whereas hexamethonium changed the Tyr bands to more negative, indicating that the site of binding of agonists and antagonists and their effect on the conformation of the receptor may be different. Decamethonium, procaine, and lidocaine had no effect on both the far- and near-UV CD spectra of acetylcholine receptor.

Electronic Resource

1573-4943

Basic fibroblast growth factor ; circular dichroism ; trifluoroethanol ; sodium dodecyl sulfate

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract The conformation of the 153-residue form of human basic fibroblast growth factor (bFGF) was studied with circular dichroism (CD) and sequence prediction methods. The far-UV CD spectrum with a minimum at 202 nm resembled that of an unordered polypeptide/protein or a protein rich in distorted antiparallel β-sheets. Analysis of the CD spectrum by the least-squares method of Changet al. (1978) and the CONTIN program of Provencher and Glöckner (1981) suggested that about one half of the molecule consisted of β-sheet and there was no α-helix. These estimates agreed with the prediction by the sequence method of Garnieret al. (1978) using decision constants based on CD results. bFGF had an unusual CD band at 187 nm, which disappeared upon ionization of Tyr side chains atpH 11.7. It also had another unusual property of irreversibly converting the CD spectrum to a helix-like one with a double minimum at 205 and 215 and a maximum at 189 nm upon heating the solution to above 55°C. The helicity was also enhanced in trifluoroethanol and in sodium dodecyl sulfate. The mutant bFGF in which cysteines 76 and 94 were replaced by serine residues had essentially the same properties as the wild-type.

Electronic Resource

1573-4943

Bilirubin oxidase ; circular dichroism ; conformation ; denaturation

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract The conformation of bilirubin oxidase (EC 1.3.3.5) fromMyrothecium verrucaria was studied by circular dichroism (CD). The far-UV CD spectrum showed a single minimum at 215 nm and a maximum near 198 nm, suggesting the dominance ofβ-sheets. There was another negative band at 187 nm that is absent from the spectra of modelα-helix orβ-sheet. CD analysis by the method of Changet al. agreed well with the estimates based on the Chou and Fasman sequence-predictive method, but the Provencher-Glöckner method of CD analysis agreed well with the sequence-predictive method of Garnieret al. AtpH 12 the 215- and 187-nm bands completely disappeared and the protein was denatured. This denaturation was accompanied by the appearance of a large positive band at 250 nm, probably due to ionization of tyrosine residues. In 20 mM sodium dodecyl sulfate the magnitude of the 215-nm band increased, but the spectrum transformed to that of partial helices after heating at 100°C. In 6 M guanidine hydrochloride the far-UV CD spectrum was monotonic and became more negative at the lower wavelength limit (near 212 nm), suggesting that the secondary structure of the protein was disrupted. However, the near-UV CD spectrum retained residual aromatic bands even after heating at 100°C. Thus, our denaturation studies suggest that bilirubin oxidase has a rigid tertiary structure.

Electronic Resource