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861.
The centrality dependences of the experimental rapidity as well as transversemomentumversus rapidity spectra of negative pions were analyzed quantitatively in 12C+12C and 12C+181Ta collisions at 4.2 GeV/c per nucleon using fitting the pion spectra by Gaussian distribution function. The experimental results were compared systematically with the predictions of the Quark-Gluon-String Model (QGSM) adapted to intermediate energies. 相似文献
862.
First Report for Electrochemical Determination of Levodopa and Cabergoline: Application for Determination of Levodopa and Cabergoline in Human Serum,Urine and Pharmaceutical Formulations 下载免费PDF全文
The electrochemical oxidation of levodopa on the surface of a carbon paste electrode modified with graphene nanosheets, 1‐(4‐bromobenzyl)‐4‐ferrocenyl‐1H‐[1,2,3]‐triazole (1,4‐BBFT) and hydrophilic ionic liquid (n‐hexyl‐3‐methylimidazolium hexafluoro phosphate) as a binder is studied. It has been found that the oxidation of levodopa at the surface of a modified electrode occurs at a potential of about 210 mV less positive than that of an unmodified carbon paste electrode (CPE). The prepared modified electrode exhibits a very good resolution of the voltammetric peaks of levodopa and cabergoline. The electrode has been applied successfully for the determination of levodopa and cabergoline in some real samples. 相似文献
863.
Mukhtar MR Hadi AH Rondeau D Richomme P Litaudon M Mustafa MR Awang K 《Natural product research》2008,22(11):921-926
The phytochemical study of the bark of Malaysian Phoebe scortechinii (Lauraceae) has resulted in the isolation and identification of two new proaporphine alkaloids; (+)-scortechiniine A (1) and (+)-scortechiniine B (2) together with two known proaporphines; (-)-hexahydromecambrine A (3), (-)-norhexahydromecambrine A (4), and one aporphine; norboldine (5). Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D and 2D (1)H and (13)C NMR. 相似文献
864.
Boskabady MH Jafari Z Pouraboli I Babazade B Rahbardar MG 《Natural product research》2012,26(16):1523-1528
The effects of three concentrations of aqueous-ethanolic extract, 10?nM atropine and saline on muscarinic receptors were tested on two groups of non-incubated (group 1; n?=?7) and incubated tracheal chains with propranolol and chlorpheniramine (group 2; n?=?6). The EC?? of higher concentration of the extract (2?μg?mL?1) in group 2 was significantly greater than those of group 1 (p?0.01). The maximum response obtained in the presence of all concentrations of extract in groups 1 and 2 were lower than saline (p?0.05 to 0.001). There were parallel rightward shifts in the concentration response curves obtained for all concentrations of the extract in group 2. There was significant and positive correlation between the concentrations and the values of EC?? in group 1 (p?0.05) and group 2 (p?0.001). These results indicate an anti-cholinergic effect of Zataria multiflora Boiss on the tracheal chains of guinea pigs. A β-adrenoceptor stimulatory effect for the plant was also suggested. 相似文献
865.
A new electrochemical sensor for determination of isoproterenol(IP) is described.The sensor is based on carbon paste electrode (CPE) modified with 5-amino-2’,4’-dimethoxybiphenyl-2-ol(5ADMB) and takes the advantages of carbon nanotubes(CNTs). Under the optimum pH of 7.0,the oxidation of IP occurs at a potential about 210 mV less positive than that of the unmodified CPE. The oxidation currents increased linearly with two concentration intervals of IP,one is 0.09 to 20.0 |xmol/L and,the other is 20.0 to 400.0μmol/L.The detection limit(3σ) obtained by square wave voltammetry(SWV) was 39.0 nmol/L.The practical application of the modified electrode was demonstrated by determining IP in IP ampoule,urine and human blood serum samples. 相似文献
866.
This paper deals with the study of parametric oscillation of an electrostatically actuated microbeam using variational iteration method. The paper considers a micro-beam suspended between two conductive micro-plates, subjected to a same actuation voltage. The nonlinear governing differential equation of motion about static equilibrium position using calculus of variation theory and Taylor series expansion has been linearized and implementing a Galerkin based reduced order model a Mathieu type equation has been obtained. By improving variational iteration method combining with method of strained parameters transition curves, separating stable from unstable regions have been obtained. The results of variational iteration method, perturbation and direct numerical integration methods for some cases selected from different regions (stable and unstable regions) have been compared. 相似文献
867.
Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold (111) were irradiated with low-power UV light. Scanning tunneling microscope images recorded in situ show unusual structural changes. In the case of 2-anthracenethiol, structures measuring 4-7 nm wide and 30-40 nm in length are formed. Images taken 10 min after irradiation ceased to show further surface reorganization. With 2-naphthalenethiol SAMs, smaller structures form upon irradiation, which subsequently revert to resemble the original structure after time. 相似文献
868.
** E-mail: k.aithadi{at}ucam.ac.ma In this paper, we investigate optimal control problem governedby variational inequality of the obstacle type. Existence ofsolution for the problem is proved and we also show how to obtainoptimality conditions for a penalized problem issued from theoriginal one. 相似文献
869.
Ziziphus nummularia Attenuates the Malignant Phenotype of Human Pancreatic Cancer Cells: Role of ROS
Joelle Mesmar Manal M. Fardoun Rola Abdallah Yusra Al Dhaheri Hadi M. Yassine Rabah Iratni Adnan Badran Ali H. Eid Elias Baydoun 《Molecules (Basel, Switzerland)》2021,26(14)
Pancreatic cancer (PC) is the fourth leading cause of all cancer-related deaths. Despite major improvements in treating PC, low survival rate remains a major challenge, indicating the need for alternative approaches, including herbal medicine. Among medicinal plants is Ziziphus nummularia (family Rhamnaceae), which is a thorny shrub rich in bioactive molecules. Leaves of Ziziphus nummularia have been used to treat many pathological conditions, including cancer. However, their effects on human PC are still unknown. Here, we show that the treatment of human pancreatic ductal adenocarcinoma cells (Capan-2) with Ziziphus nummularia ethanolic extract (ZNE) (100–300 μg/mL) attenuated cell proliferation in a time- and concentration-dependent manner. Pretreatment with N-acetylcysteine, an ROS scavenger, attenuated the anti-proliferative effect of ZNE. In addition, ZNE significantly decreased the migratory and invasive capacity of Capan-2 with a concomitant downregulation of integrin α2 and increased cell–cell aggregation. In addition, ZNE inhibited in ovo angiogenesis as well as reduced VEGF and nitric oxide levels. Furthermore, ZNE downregulated the ERK1/2 and NF-κB signaling pathways, which are known to drive tumorigenic and metastatic events. Taken together, our results suggest that ZNE can attenuate the malignant phenotype of Capan-2 by inhibiting hallmarks of PC. Our data also provide evidence for the potential anticancer effect of Ziziphus nummularia, which may represent a new resource of novel anticancer compounds, especially ones that can be utilized for the management of PC. 相似文献
870.
Karzan A. Abdalkarim Shujahadeen B. Aziz Rebar T. Abdulwahid Saad M. Alshehri Tansir Ahamad Jihad M. Hadi Sarkawt A. Hussein 《Arabian Journal of Chemistry》2021,14(7):103215
This study explored a new approach to fabricate the Schiff base ligand system from both ethylenediamine and 3-chloro-2-butanone. Through coordination chemistry, the mercury Hg (II) complex was achieved from the ligand and then embedded in the polyvinyl alcohol (PVA) host using a solution casting technique to prepare polymer composites (PCs). Both UV–visible and Fourier-transform infrared (FTIR) spectroscopies highlighted the formation of the Hg (II) metal complex. These techniques confirmed the synthesis of the Hg (II) metal complex. The X-ray diffraction (XRD) pattern of the polymer composite has shown a significant enhancement in its amorphous nature compared to the pure PVA host. The thermal analysis spectra for the Hg (II) complex revealed high thermal stability. The occurrence of the complexation between the Hg (II) and host matrix of the PVA was identified from the wide shifting of UV–vis absorption and peak shifting with intensity reduction of the FTIR spectra. Tauc's method has been employed to evaluate the optical band gap, and determine the types of electronic transitions. The results have shown that the samples were exhibiting an indirect forbidden electron transition, with a significant reduction in the optical band gap of a doped sample that approaching inorganic semiconductor based-materials. In addition, the optical study has exposed the role of the Hg (II) complex in tuning the refractive index of the host polymer. Ultimately, the absorption edge was found to be shifted to the lower photon energy upon the insertion of the Hg (II) complex. The PVA doped sample displayed a substantial shift in band gap from 6.2 eV to 1.2 eV. 相似文献