4,196 research outputs found
Partial Purification and Characterization of Pectin Methyl Esterase in Southern Peas (\u3cem\u3eVigna sinesis\u3c/em\u3e)
The purposes of this study were to partially purify pectin methyl esterase (PME) of Southern peas (Vigna sinensis), to determine optimum pH and NaC1 concentration for maximum enzyme activity, to measure the energy of activation and kinetic reactions, and to ascertain the presence of multiple molecular forms of the enzyme and their isoelectric points.
PME was extracted from an acetone powder preparation and purified by a two-step ammonium sulfate fractionation and dialysis. The activity of the partially purified enzyme was significantly (p \u3c 0.05) influenced by pH, NaC1 concentration, and the interaction between pH and NaC1 concentration. The optimum pH and NaC1 concentration were 7.9 and 0.25 M, respectively. The energies of activation were calculated to be 4,900, 5,950, and 6,900 calories/mole at pH 6.0, 7.0, and 7.0, respectively. PME had a Km of 0.781% pectin N.F. and a Vmax of 24.34 PME units.
Additional purification was achieved by means of column chromatography on DEAE-cellulose and Spehadex G-100. The PME preparation thus obtained was subjected to gel electrofocusing. One PME component and two protein components were detected. The isoelectric point of the PME was 4.5 at 20° C
Electrical Investigation of the Oblique Hanle Effect in Ferromagnet/Oxide/Semiconductor Contacts
We have investigated the electrical Hanle effect with magnetic fields applied
at an oblique angle ({\theta}) to the spin direction (the oblique Hanle effect,
OHE) in CoFe/MgO/semiconductor (SC) contacts by employing a three-terminal
measurement scheme. The electrical oblique Hanle signals obtained in
CoFe/MgO/Si and CoFe/MgO/Ge contacts show clearly different line shapes
depending on the spin lifetime of the host SC. Notably, at moderate magnetic
fields, the asymptotic values of the oblique Hanle signals (in both contacts)
are consistently reduced by a factor of cos^2({\theta}) irrespective of the
bias current and temperature. These results are in good agreement with
predictions of the spin precession and relaxation model for the electrical
oblique Hanle effect. At high magnetic fields where the magnetization of CoFe
is significantly tilted from the film plane to the magnetic field direction, we
find that the observed angular dependence of voltage signals in the CoFe/MgO/Si
and CoFe/MgO/Ge contacts are well explained by the OHE, considering the
misalignment angle between the external magnetic field and the magnetization of
CoFe.Comment: 19 pages, 8 figure
EFFECT OF THE MECHANICAL CONSTRAINTS ON MULTI-FINGER PREHENSION
INTRODUCTION: When a finger produces a force, other non-task fingers of the hand also produce an involuntary force. This phenomenon has been known as finger enslaving (Zatsiorsky et al. 1998). In the present study, we examined the characteristics of the enslaving matrices obtained by the fixed object prehension and the free object prehension. Previous studies showed that two innate constraints (i.e. peripheral and central constraints) affect the performance of finger force production during fixed object prehension. However, it is unknown how the mechanical constraints, which are imposed externally, play a role in grasping tasks. The purpose of the current study was to investigate the finger enslaving for the fixed and free object prehension during maximum finger force production tasks in statics.
The central nervous system (CNS) is required to satisfy linear and rotational equilibrium during the free object prehension, while the CNS does not need to satisfy any external constraint
Quantum multi-programming for Grover's search
Quantum multi-programming is a method utilizing contemporary noisy
intermediate-scale quantum computers by executing multiple quantum circuits
concurrently. Despite early research on it, the research remains on quantum
gates or small-size quantum algorithms without correlation. In this paper, we
propose a quantum multi-programming (QMP) algorithm for Grover's search. Our
algorithm decomposes Grover's algorithm by the partial diffusion operator and
executes the decomposed circuits in parallel by QMP. We proved that this new
algorithm increases the rotation angle of the Grover operator which, as a
result, increases the success probability. The new algorithm is implemented on
IBM quantum computers and compared with the canonical Grover's algorithm and
other variations of Grover's algorithms. The empirical tests validate that our
new algorithm outperforms other variations of Grover's algorithms as well as
the canonical Grover's algorithm
Tgif1 Counterbalances The Activity Of Core Pluripotency Factors In Mouse Embryonic Stem Cells
Core pluripotency factors, such as Oct4, Sox2, and Nanog, play important roles in maintaining embryonic stem cell (ESC) identity by autoregulatory feedforward loops. Nevertheless, the mechanism that provides precise control of the levels of the ESC core factors without indefinite amplification has remained elusive. Here, we report the direct repression of core pluripotency factors by Tgif1, a previously known terminal repressor of TGF beta/activin/nodal signaling. Overexpression of Tgif1 reduces the levels of ESC core factors, whereas its depletion leads to the induction of the pluripotency factors. We confirm the existence of physical associations between Tgif1 and Oct4, Nanog, and HDAC1/2 and further show the level of Tgif1 is not significantly altered by treatment with an activator/inhibitor of the TGF beta/activin/nodal signaling. Collectively, our findings establish Tgif1 as an integral member of the core regulatory circuitry of mouse ESCs that counterbalances the levels of the core pluripotency factors in a TGF beta/activin/nodal-independent manner.Cancer Prevention Research Institute of Texas (CPRIT) R1106Molecular Bioscience
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