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91.
The aim of this study was to evaluate the gastroprotective efficacy of andrographolide isolated from Andrographis paniculata in rats induced with duodenal ulcers. Duodenal ulcers were induced by cysteamine administration in rats pretreated with 3?mg?kg?1 BW?day?1 of andrographolide for 30 days. Ulcer score, myeloperoxidase activity, TBARS level, GSH/GSSG ratio and enzyme antioxidants were measured in the duodenal tissue. Brush border and basolateral membranes were isolated to assay sucrase, maltase, alkaline phosphatase and total ATPases. Ulcer score was significantly minimised in rats pretreated with andrographolide. Elevation in myeloperoxidase and TBARS levels were found to be minimised significantly due to andrographolide treatment. Membrane-bound enzyme activities and the thiol redox status of glutathione were significantly maintained in duodenal mucosa of rats that received andrographolide. This study reveals that the major component of A. paniculata, andrographolide, has potent antiulcer properties that are most likely caused by minimising inflammatory changes, counteracting free radical formation and maintaining the thiol redox status in the duodenum. 相似文献
92.
The crystal structure of p-[N,N-bis(2-chloroethyl)amino]benzaldehyde-4-phenyl thiosemicarbazone(CEAB-4-PTSC) is described. The compound crystallizes in the monoclinic crystal system, P21/c space group, Z = 4, calculated density = 1.327 mg/cm3, V = 1978.2(6) ?3 with unit cell parameters a = 16.240(3) ?, b = 12.821(2) ?, c = 9.8543(16) ?, ?? = 105.382(6)°. The crystal structure reveals that the compound exists in the thione form and S1 and N2 are at trans-conformation to each other with respect to the N3-C12 bond. The packing of molecules in the crystal lattice is stabilized by intramolecular hydrogen bonds. 相似文献
93.
S. Parthiban H. Anandalakshmi S. Senthilkumar V. Karthikeyan S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2012,108(3):881-885
We have prepared pure and divalent vanadyl ion-doped magnesium rubidium sulfate hexahydrate crystals by using slow evaporation solution growth technique. It is interesting to observe that Vo(II) doping influences the physical properties of MRSH. Presence of Vo(II) ions in the doped specimen was confirmed by energy dispersive spectroscopy and electron paramagnetic resonance spectroscopy. FTIR studies reveal that the doping of vanadium ion has not altered the basic structure of MRSH. Scanning electron microscope studies of doped sample reveals that structure defect centers are formed in the crystals. Gradual decomposition patterns were observed for pure and doped specimens in thermogravimetry and differential thermogravimetry. The grown crystals were also characterized by powder X-ray diffraction. The second harmonic generation efficiency tested using Kurtz powder technique is not influenced by the added dopant. 相似文献
94.
Ramachandran G Karthikeyan NS Giridharan P Sathiyanarayanan KI 《Organic & biomolecular chemistry》2012,10(28):5343-5346
A simple and efficient three components domino reaction of γ-butyrolactam (2-pyrrolidinone), aromatic aldehyde and substituted thiophenol catalyzed by elemental iodine resulted in the formation of 1-((phenylthio)(phenyl)methyl)pyrrolidin-2-one derivatives. The stability of the synthesized analogues was evaluated in stimulated gastric fluid (SGF) and bovine serum albumin (BSA). In vitro anticancer activity was investigated in the low micromolar range and a few analogues were found to possess good activity. This current protocol provides several advantages like shorter reaction time, excellent yield and convenient work-up. 相似文献
95.
Jesus M. Munoz-Pacheco Christos Volos Fernando E. Serrano Sajad Jafari Jacques Kengne Karthikeyan Rajagopal 《Entropy (Basel, Switzerland)》2021,23(7)
In this paper, the stabilization and synchronization of a complex hidden chaotic attractor is shown. This article begins with the dynamic analysis of a complex Lorenz chaotic system considering the vector field properties of the analyzed system in the domain. Then, considering first the original domain of attraction of the complex Lorenz chaotic system in the equilibrium point, by using the required set topology of this domain of attraction, one hidden chaotic attractor is found by finding the intersection of two sets in which two of the parameters, r and b, can be varied in order to find hidden chaotic attractors. Then, a backstepping controller is derived by selecting extra state variables and establishing the required Lyapunov functionals in a recursive methodology. For the control synchronization law, a similar procedure is implemented, but this time, taking into consideration the error variable which comprise the difference of the response system and drive system, to synchronize the response system with the original drive system which is the original complex Lorenz system. 相似文献
96.
The desulfurization reaction introduced by Yan and Dawson as a postnative chemical ligation step greatly expanded the scope of ligation chemistry beyond Xaa-Cys (Xaa is any amino acid) by making ligation at Xaa-Phe, Xaa-Val, Xaa-Lys, Xaa-Leu, Xaa-Thr, and Xaa-Pro junctions accessible in the synthesis of functional proteins. A new ligation site based on Xaa-Gln utilizing γ-mercaptoglutamine is reported, and several examples on the efficiency of ligation coupled with desulfurization are provided. 相似文献
97.
Karthikeyan?Krishnamoorthy Murugan?Veerapandian Rajneesh?Mohan Sang-Jae?KimEmail author 《Applied Physics A: Materials Science & Processing》2012,106(3):501-506
In this paper, we are investigating the Raman and photoluminescence properties of reduced graphene oxide sheets (rGO). Moreover,
graphene oxide (GO) sheets are synthesized using Hummer’s method and further reduced into graphene sheets using D-galactose.
Both GO and rGO are characterized by UV-vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS)
and Thermogravimetric (TGA) analysis. Raman analysis of rGO shows the restoration of graphitic domains in GO after reduction.
The photoluminescence of rGO showed emission in the UV region which is blue shifted along with luminescent quenching as compared
to GO. This blue shift and quenching in photoluminescence arises due to the newly formed crystalline sp2 clusters in rGO which created percolation pathways between the sp2 clusters already present. 相似文献
98.
The present study involves the analysis of surface nanostructures and its variation present in the hind wing of dragon fly (Sympetrum vulgatum) using atomic force microscopy (AFM). The hindwing was dissected into 4 parts (D1-D4) and each dissected section was analyzed using AFM in tapping mode at different locations. The AFM analysis revealed the presence of irregular shaped nanostructures on the surface of the wing membrane with size varying between 83.25±1.79 nm to 195.08±10.25 nm. The size and shape of the nanostructure varied from tip (pterostigma) to the costa part. The membrane surface of the wing showed stacked arrangement leading to increase in size of the nanostructure. Such arrangement of the nanostructures has lead to the formation of nanometer sized valleys of different depth and length on the membrane surface giving them ripple wave morphology. The average roughness of the surface nanostructures varied from 18.58±3.12 nm to 24.25±8.33 nm. Surfaces of the wings had positive skewness in D1, D2 and D4 regions and negative skewness in D3 region. These surface nanostructures may contribute asymmetric resistance under mechanical loading during the flight by increasing the bending and torsional resistance of the wing. 相似文献
99.
Thin films of polymer electrolytes comprising of PVA and KOH (A) with and without the addition of zinc salts, viz., zinc acetate (B) and zinc triflate (C) as mixed cations were prepared via. solution casting method. The thermal stability and ionic conductivity of PVA–KOH solid
polymer electrolyte (A) were improved by the partial substitution of KOH with zinc salts. Among the two salts, zinc triflate was found to improve
both the physical as well as electrochemical properties of the PVA–KOH films more significantly than zinc acetate. An attempt
to optimize the ratio of various components of polymer electrolytes, viz., polymer: KOH: zinc salt was also made, based on
the dimensional stability and ionic conductivity values. Finally, the select category polymer film containing PVA–KOH–zinc
triflate (C) in an optimum ratio of 40:35:25 was deployed in coin cell fabrication and subjected to charge–discharge studies with a view
to demonstrate the possible electrochemical reversibility characteristics. Based on the encouraging results obtained from
the cycling study, C type films [PVA–KOH–zinc triflate] qualify themselves as potential polymer electrolytes for use in rechargeable Zn/AgO polymer
batteries. 相似文献
100.
ZnCo2O4 nanomaterial was prepared by co-precipitation method and characterized by X-ray diffraction (XRD), scanning electron microscope
(SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), and galvanostatic charge–discharge tests at various
current densities. It is shown that the crystal structure and surface morphology play an important role in the enhancement
of the specific capacitance. The TEM results clearly indicate that the prepared material shows aggregated particles. The particle
size powder was about 50 nm, and SEM pictures indicate a porous morphology. The electrochemical behavior of ZnCo2O4 was characterized by mixing equal proportion of carbon nanofoam (CNF). From CV, it is concluded that the combination of redox
and pseudo-capacitance increases the specific capacitance up to 77 F g−1 at 5 mV s−1 scan rate. The ZnCo2O4-based supercapacitor cell has good cyclic stability and high coulombic efficiency. 相似文献