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411.
The effect of Dzyaloshinskii-Moriya (D-M) interaction on the bistable nano-scale soliton switching offers the possiblity of developing a new innovative approach for data storage technology. The dynamics of Heisenberg ferromagnetic spin system is expressed in terms of generalized inhomogeneous higher order nonlinear Schr6dinger (NLS) equation. The bistable soliton switching in the ferromagnetic medium is established by solving the associated coupled evolution equations for amplitude and velocity of the soliton using the fourth order Runge-Kutta method numerically. 相似文献
412.
Gopi Ambikapathi Suresh Kumar Kempahanumakkagari Babu Ramappa Lamani Devaraju Kuramkote Shivanna Harish Bodagur Maregowda Anushree Gupta Pandurangappa Malingappa 《Journal of fluorescence》2013,23(4):705-712
Peroxynitrite is a potent oxidizing and nitrating agent which has detrimental effects on cells by altering the structure and function of biomolecules present within. A fluorescent probe rhodamine B phenyl hydrazide (RBPH) has been proposed for peroxynitrite (ONOO?) imaging in MCF-7 cells based on its oxidation property, which converts RBPH to pink colored and highly fluorescent rhodamine B. The fluorescence emission intensity of the rhodamine B produced in the above process is linearly related to the concentration of peroxynitrite. The method obeys Beer’s law in the concentration range 2–20 nM and the detection limit has been found to be 1.4 nM. The possible reaction mechanism of peroxynitrite with RBPH to produce rhodamine B has been discussed with spectroscopic evidence. The Probe is selective to the peroxynitrite in the pH range 6–8 which is near physiological pH. Fluorescence microscopic studies suggest that the probe is cell permeable and hence peroxynitrite was imaged in MCF-7 cells. 相似文献
413.
Guneet Kaur Ashok K. Srivastava Subhash Chand 《Applied biochemistry and biotechnology》2012,167(5):1061-1068
Repeated batch cultivation (empty-and-fill protocol) using obligate anaerobe Clostridium diolis was attempted in the present study to improve the production of 1,3-propanediol (1,3-PD). In repeated batch operation, 20?% (v/v) culture broth was removed from the bioreactor and supplemented with an equal volume of fresh nutrient medium when the residual glycerol concentration in the bioreactor decreased below 15?g/L. Four cycles of culture broth withdrawal and subsequent replacement resulted in achieving a 1,3-PD concentration of 67.8?g/L with a productivity of 1.04?g/L/h at the end of 65?h. This represented a 1,3-PD concentration and productivity enhancement by 2.6-fold and 1.5-fold, respectively, as compared to batch 1,3-PD fermentation. This is the first report on the use of repeated batch mode of bioreactor operation for enhanced 1,3-PD production. 相似文献
414.
HosahudyaN. Gopi RituparnaS. Roy SrinivasaR. Raghothama IsabellaL. Karle Padmanabhan Balaram 《Helvetica chimica acta》2002,85(10):3313-3330
The incorporation of the β‐amino acid residues into specific positions in the strands and β‐turn segments of peptide hairpins is being systematically explored. The presence of an additional torsion variable about the C(α) C(β) bond (θ) enhances the conformational repertoire in β‐residues. The conformational analysis of three designed peptide hairpins composed of α/β‐hybrid segments is described: Boc‐Leu‐Val‐Val‐DPro‐β Phe ‐Leu‐Val‐Val‐OMe ( 1 ), Boc‐Leu‐Val‐β Val ‐DPro‐Gly‐β Leu ‐Val‐Val‐OMe ( 2 ), and Boc‐Leu‐Val‐β Phe ‐Val‐DPro‐Gly‐Leu‐β Phe ‐Val‐Val‐OMe ( 3 ). 500‐MHz 1H‐NMR Analysis supports a preponderance of β‐hairpin conformation in solution for all three peptides, with critical cross‐strand NOEs providing evidence for the proposed structures. The crystal structure of peptide 2 reveals a β‐hairpin conformation with two β‐residues occupying facing, non‐H‐bonded positions in antiparallel β‐strands. Notably, βVal(3) adopts a gauche conformation about the C(α) C(β) bond (θ=+65°) without disturbing cross‐strand H‐bonding. The crystal structure of 2 , together with previously published crystal structures of peptides 3 and Boc‐β Phe ‐β Phe ‐DPro‐Gly‐β Phe ‐β Phe ‐OMe, provide an opportunity to visualize the packing of peptide sheets with local ‘polar segments' formed as a consequence of reversal peptide‐bond orientation. The available structural evidence for hairpins suggests that β‐residues can be accommodated into nucleating turn segments and into both the H‐bonding and non‐H‐bonding positions on the strands. 相似文献
415.
Saikat Pahan Dr. Sanjit Dey Dr. Gijo George Souvik Panda Mahapatra Dr. DRGKoppalu R. Puneeth Kumar Prof. Hosahudya. N. Gopi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(2):e202316309
Chirality is ubiquitous in nature, and homochirality is manifested in many biomolecules. Although β-double helices are rare in peptides and proteins, they consist of alternating L- and D-amino acids. No peptide double helices with homochiral amino acids have been observed. Here, we report chiral β-double helices constructed from γ-peptides consisting of alternating achiral (E)-α,β-unsaturated 4,4-dimethyl γ-amino acids and chiral (E)-α,β-unsaturated γ-amino acids in both single crystals and in solution. The two independent strands of the same peptide intertwine to form a β-double helix structure, and it is stabilized by inter-strand hydrogen bonds. The peptides with chiral (E)-α,β-unsaturated γ-amino acids derived from α-L-amino acids adopt a (P)-β-double helix, whereas peptides consisting of (E)-α,β-unsaturated γ-amino acids derived from α-D-amino acids adopt an (M)-β-double helix conformation. The circular dichroism (CD) signature of the (P) and (M)-β-double helices and the stability of these peptides at higher temperatures were examined. Furthermore, ion transport studies suggested that these peptides transport ions across membranes. Even though the structural analogy suggests that these new β-double helices are structurally different from those of the α-peptide β-double helices, they retain ion transport activity. The results reported here may open new avenues in the design of functional foldamers. 相似文献
416.
417.
Prakash Chand 《International Journal of Theoretical Physics》1969,2(3):309-312
In the present note we study theJ
P assignment for the B-meson using the available experimental results. We study the consequences of such assignments from the point of view ofSU
3 classification. This leads to many interesting results and provides a way to decide if the B-meson is a resonance or only an enhancement. 相似文献
418.
While studying neutron deflections produced by a magnetic prism, we have stumbled upon a simple ‘geometric’ formula. For a
prism of refractive indexn close to unity, the deflection simply equals the product of the refractive powern − 1 and the base-to-height ratio of the prism, regardless of the apex angle. The base and height of the prism are measured
respectively along and perpendicular to the direction of beam propagation within the prism. The geometric formula greatly
simplifies the optimisation of prism parameters to suit any specific experiment. 相似文献
419.
The differential cross section for the electron scattering accompanied by simultaneous absorption or emisson of one Raman
photon and the inverse bremsstrahlung process in an intense laser beam is calculated. 相似文献
420.
Chand, A., McQuillan, A.R. and Fenby, D.V., 1979. Thermodynamic study of systems with lower critical solution temperatures: H2O + (C2H5)3N, D2O + (C2H5)3N. Fluid Phase Equilibria, 2: 263–274.Molar excess enthalpies and molar excess volumes are reported for the systems H2O + (C2H5)3N and D2O + (C2H5)3N at temperatures below and above their lower critical solution temperatures. The molar excess enthalpies are slightly less exothermic for the D2O system. The molar excess volumes of the H2O and D2O systems are within experimental error of one another. Compositions of conjugate solutions estimated from the calorimetric and volumetric measurements agree with those obtained from published liquid—liquid phase diagrams. 相似文献