排序方式: 共有70条查询结果,搜索用时 78 毫秒
51.
Seyed Mehdi Razavi Ameneh Ravansalar Shahabeddin Mirinejad 《Natural product research》2015,29(21):2037-2040
Ferulago angulata (Schlecht) Boiss (Apiaceae) is a perennial herb distributed in the central parts of Iran. In this work, the essential oil of Ferulago angulat a aerial parts collected from the central parts of Iran was obtained by using hydrodistillation analysed by GC and GC–MS. Air-dried and powdered plant roots were extracted with n-hexane, dichloromethane and methanol, respectively, using a Soxhlet apparatus. The n-hexane extract was subjected to preparative thin-layer chromatography using chloroform–acetone (95:5) as solvent system to yield two linear furanocoumarins, prantschimgin and oxypeucedanin. The structure of theisolated compounds was elucidated by using spectroscopic data such as 1H NMR, 13C NMR, UV and IR. The results of GC–MS analyses showed that γ-terpinolene (11.97%), α-pinene (10.00%), sabinene (6.89%), linalool (5.56%) and cis-ocimene (4.41%) were the main components among 51 constituents characterised in the oil. The oil exhibits considerable phytotoxic activity. 相似文献
52.
We present the bound state solution of Schr?dinger equation in D dimensions for quadratic exponential-type potential for arbitrary l-state. We use generalized parametric Nikiforov–Uvarov method to obtain the energy levels and the corresponding eigenfunction in closed form. We also compute the energy eigenvalues numerically. 相似文献
53.
The present study explores 3D spatial arrangements of the A- and B-cells within the fifth lumbar dorsal root ganglion (DRG) of rat in order to test for differences after sciatic nerve crush (SNC). The pair correlation and cross-correlation functions were estimated through counting dipole probes superimposed on DRG sections. The data showed that the A- and B-cells were clustered at distances below 40 and 35 μm in sham-operated animals, respectively. These values were 35 and 25 μm in SNC animals. Beyond these distances, the cells of the control group were arranged neither clustered nor repulsed. The A- and B-cells showed a negative correlation (repulsion) at r = 270–290 μm and r = 100 in SNC ganglions, respectively. The plot of the cross-correlation function showed that the first maximum curve was r = 51 μm and 41 μm in sham-operated and SNC rats, respectively. The other differences were seen at r = 51–61 μm and r = 165 μm between cross-covariance of the cells. The “degree of order” for the A- and B-cells showed no significant difference and the low values of the two groups indicated the random distribution of cells in them.
Conclusion
The obtained data revealed that cellular spatial patterns in the dorsal root ganglion of the sciatic nerve crush were changed. 相似文献54.
The article reports on the unique manipulation of the acid-catalyzed reaction of [2-aminoporphyrinato(2-)]nickel with formaldehyde to form selectively either the symmetric Tröger’s base or the asymmetric spiro Tröger’s base bis(metalloporphyrin) derivative. The reaction is driven by the choice of acid catalyst, formaldehyde source, and particularly, solvent, to give a mixture of both derivatives in preparative yields of about 90%, or to give selectively one of the derivatives in a yield of about 60%. 相似文献
55.
Using the Nikiforov-Uvarov (NU) method, pseudospin and spin symmetric solutions of the Dirac equation for the scalar and vector Hulthén potentials with the Yukawa-type tensor potential are obtained for an arbitrary spin-orbit coupling quantum number κ. We deduce the energy eigenvalue equations and corresponding upper- and lower-spinor wave functions in both the pseudospin and spin symmetry cases. Numerical results of the energy eigenvalue equations and the upper- and lower-spinor wave functions are presented to show the effects of the external potential and particle mass parameters as well as pseudospin and spin symmetric constants on the bound-state energies and wave functions in the absence and presence of the tensor interaction. 相似文献
56.
We investigate the approximate solution of the Dirac equation for a combination of Mobius square and Mie type potentials under the pseudospin symmetry limit by using supersymmetry quantum mechanics. We obtain the bound-state energy equation and the corresponding spinor wave functions in an approximate analytical manner. We comment on the system via various useful figures and tables. 相似文献
57.
The Klein–Gordon equation with vector and scalar Woods–Saxon potentials is solved in terms of hypergeometric functions. The transmission and reflection coefficients as well as the bound state solutions are reported. 相似文献
58.
Akpan N. Ikot Elham Maghsoodi Saber Zarrinkamar Hassan Hassanabadi 《Few-Body Systems》2013,54(11):2027-2040
The Dirac equation for the combined Mobius square and inversely quadratic Yukawa potentials including a Coulomb-like interaction term has been investigated in the presence of spin and pseudospin symmetries with arbitrary spin-orbit quantum number κ .We have obtained the explicit energy eigenvalues and the corresponding eigenfunctions by the framework of Nikiforov-Uvarov method. 相似文献
59.
Akpan N. Ikot Oladunjoye A. Awoga Akaninyene D. Antia Hassan Hassanabadi Elham Maghsoodi 《Few-Body Systems》2013,54(11):2041-2051
We study the D-dimensional Klein-Gordon equation for the modified Hylleraas potential with position dependent mass. We obtain the energy eigenvalues and the corresponding eigenfunctions for any arbitrary l-state using the parametric Nikiforov-Uvarov method. New elegant approximation method is used to deal with the centrifugal term. We also discuss the two limiting cases of this potential, i.e. the Woods-Saxon and Rosen-Morse potentials. 相似文献
60.
Dr. Zbigniew Zawada Dr. Ameneh Tatar Dr. Pavle Mocilac Dr. Miloš Buděšínský Dr. Tomáš Kraus 《Angewandte Chemie (International ed. in English)》2018,57(31):9891-9895
Chemically modified nucleoside triphosphates (NTPs) are widely exploited as unnatural metabolites in chemical biology and medicinal chemistry. Because anionic NTPs do not permeate cell membranes, their corresponding neutral precursors are employed in cell‐based assays. These precursors become active metabolites after enzymatic conversion, which often proceeds insufficiently. Here we show that metabolically‐active NTPs can be directly transported into eukaryotic cells and bacteria by the action of designed synthetic nucleoside triphosphate transporters (SNTTs). The transporter is composed of a receptor, which forms a non‐covalent complex with a triphosphate anion, and a cell‐penetrating agent, which translocates the complex across the plasma membrane. NTP is then released from the complex in the intracellular milieu and accumulates in nuclei and nucleoli in high concentration. The transport of NTPs proceeds rapidly (seconds to minutes) and selectively even in the presence of other organic anions. We demonstrate that this operationally simple and efficient means of transport of fluorescently labelled NTPs into cells can be used for metabolic labeling of DNA in live cells. 相似文献