Methylation reactions at dopaminergic nerve endings, serving as biological off-switches in managing dopaminergic functions

The mechanisms for the regulation of synaptic dopamine （DA） include its release from presynaptic vesicles, its interaction with post-synaptic and pre-synaptic DA receptors, the reuptake of DA, via dopamine transporter （DAT）, the diffusion of DA and its metabolism by mono-amine oxidase （MAO） and cate- chol-O-methyl transferase （COMT）. DA controls complex and specialized functions including, movements, behavior, mood, perception, reward, and more recently, neurogenesis （Popolo et al., 2004; Reimer et al., 2013） and neuroregeneration （Hoglinger et al., 2004; Yang et al., 2008）. These functions are varied and of high fidelity. Movement, as an example, requires regulatory mechanisms for initiating, stopping, slowing-down speed- ing-up, changing directions, for governing the relentless urges to move in the young and sedentariness in the old as well as in motor-freezing, catalepsy, tremor and stereotypy.

Preparation of Functionalized Porous Silica by Ultrasonic Technique for the Methylation Reaction of Phenol with Dimethyl Carbonate

Porous silica modified with -（CH2）3NH2 （primary amine）, -（CH2）3NHCH2CH2NH2 （secondary/primary amine） and -（CH2）3N-cycl-（CH2）4 （tertiary amine） were synthesized by ultrasonic technique under mild conditions. The samples were characterized by BET, elemental analysis and TG, showing that the organosilane moieties were grafted onto the surface of porous silica by covalent bond. The structure of the organosilane moieties and ultrasonic treatment time were all significant for the quantities of grafted amino groups. The samples exhibited promising catalytic properties towards the methylation reaction of phenol with dimethyl carbonate （DMC）. The methylation reaction with the modified samples featured high selectivity at high conversion. The samples were subjected to utilization for a few recycles without obvious loss of activity to indicate that ultrasonic technique was effective for the preparation of organically modified porous silica catalysts.

Synthesis,characterization and antioxidant activities of highly functionahzed cyclopentadienes catalyzed by ZnO-nanorod as economic and efficient heterogeneous nano catalyst

A three-component condensation was applied for the preparation of cyclopentadiene derivatives through the reaction of primary amines,alkyl propiolate and dialkyl acetylenedicarboxylate in the presence of catalytic amount of ZnO-nanorods（Zn-NR） under solvent-free conditions at 50 ℃.The method has proved to be synthetically green,simple,and effective with high atom economy and yield.The catalyst also revealed significant reusability.Moreover,the antioxidant activity and free radical scavenging capacity of the newly synthesized derivatives 4a,4b,4c,and 4d was screened using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl（DPPH） and ferric reducing antioxidant power（FRAP）assays and compared with hydroxytoluene（BHT） and tert-butylhydroquinone（TBHQ）.These compounds do not exhibit good DPPH radical scavenging,but they have a desirable FRAP.

Photo-induced Synthesis and Characterization of Poly(methyl methacrylate) Grafted Sodium Salt of Partially Carboxymethylated Guar Gum

Photo-induced graft copolymerization of methyl methacrylate（MMA） onto sodium salt of partially carboxymethylated guar gum（Na-PCMGG, DS = 0.291） was carried out in an aqueous medium using ceric ammonium nitrate（CAN） as photoinitiator to synthesize a novel graft copolymer, Na-PCMGG-g-PMMA, which may find its potential application as a metal adsorbent. The influences of synthesis variables such as concentrations of photoinitiator（CAN）, nitric acid and monomer（MMA） as well as reaction time, temperature and amount of substrate on the grafting yields were studied and the reaction conditions for optimum photo-grafting were evaluated. At optimum concentration, the maximum values of the grafting yields achieved were G = 271.61% and GE = 63.89%. The experimental results were found to be in very good agreement with the proposed kinetic scheme. The photo-graft copolymerization of MMA onto Na-PCMGG（ DS = 0.291） was also carried out in the presence and absence of ultraviolet radiation for studying the efficiency of the photoinitiator. The influence of carboxymethyl groups introduced onto the guar gum molecules with regard to its behavior towards ultra-violet radiation induced grafting with MMA was also investigated. Photo-grafting process was confirmed and the products were characterized with the help of the spectroscopic（1H-NMR and FTIR） and SEM techniques.