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Motivation plays an important role in foreign language learning. Learning motivation is to promote and guide and maintain learning activities which have been conducted an internal strength or internal mechanism. Learning motivation once formed, the student will use an active learning attitude to learn, and express a keen interest in learning, and can focus attention in class to master knowledge. Through the study of the theory of modern education, this paper discusses the definition of motivation, types of motivation; the role of motivation in English learning are analyzed. The subjects in the thesis are Gejiu middle school students, and the author designed a questionnaire on English motivation. The purpose of the study was to find out the unfavorable factors. According to the results and the related theory, the author presents some suggestions to arouse the students' English motivation and improve the efficiency of English learning and teaching in Junior Middle School. Among the suggestions, the implications by the study include that students need motivation to help them learning English, they should establish the right goal to enhance them learning English well. Meanwhile, as an organizer in teaching, teacher should pay more attention to communicative learning that can stimulate students to learn effectively.

α-Synuclein, a natively unfolded protein aggregation which is implicated in the pathogenesis of Parkinson’s disease and several other neurodegenerative diseases, is known to interact with a great number of unrelated proteins. Some of these proteins, such as β-synuclein and DJ-1, were shown to inhibit α-synuclein aggregation in vitro and in vivo therefore acting as chaperones. Since calbindin-D28K is co-localized with Ca2+ neuronal membrane pumps, and since α-synuclein is also found in the membrane proximity, these two proteins can potentially interact in vivo. Here we show that calbindin-D28K interacts with α-synuclein and inhibits its fibrillation in a calcium-dependent manner, therefore potentially acting as a calcium-dependent chaperone. [ABSTRACT FROM AUTHOR]

An unprecedented O-fused ring 5,7-dihydroxy-4-methyl-2,2,3-triphenylbenzofuran-6(2 H )-one ( 3 ) was first time synthesized. Further, a series of novel dialkyl/fluoroalkyl derivatives of compound 3 , 5,7-dialkoxy/fluoroalkoxy-4-methyl-2,2,3-triphenylbenzofuran-6(2 H )-one, were obtained with noninvasive fluorescence switching characteristics and aggregation-induced emission properties. Compared with fluoroalkyl derivatives, the alkyl analogs exhibited a significant bathochromic shift in solid-state fluorescence emission. Notably, these noninvasive fluorescent molecular switches could be facilely tuned through light and heat stimulation, which successfully achieved high contrast and reversible fluorescent emission between orange and yellow endowing them with potential applications in data encryption materials. In addition, the single crystal data of compounds 3 and 7-CF 3 displayed weak intermolecular interactions in different directions, resulting in twisted conformation and antiparallel slip stacking. Interestingly, the polymer dimethyl silicone film doped with 7-C 3 F 7 also showed an evident light-responsive behavior, meeting the criterion for fluorescent materials in the optical field.

Oxidative stress and aggregation of the presynaptic protein alpha-synuclein (alpha-Syn) are implied in the pathogenesis of Parkinson's disease and several other neurodegenerative diseases. Various posttranslational modifications, such as oxidation, nitration and truncation, have significant effects on the kinetics of alpha-Syn fibrillation in vitro. alpha-Syn is a typical natively unfolded protein, which possesses some residual structure. The existence of long-range intra-molecular interactions between the C-terminal tail (residues 120-140) and the central part of alpha-Syn (residues 30-100) was recently established (Bertoncini et al. (2005) Proc Natl Acad Sci U S A 102, 1430-1435). Since alpha-Syn has four methionines, two of which (Met 1 and 5) are at the N-terminus and the other two (Met 116 and 127) are in the hydrophobic cluster at the C-terminus of protein, the perturbation of these residues via their oxidation represents a good model for studying the effect of long-range interaction on alpha-Syn fibril formation. In this paper we show that Met 1, 116, and 127 are more protected from the oxidation than Met 5 likely due to the residual structure in the natively unfolded alpha-Syn. In addition to the hydrophobic interactions between the C-terminal hydrophobic cluster and hydrophobic central region of alpha-Syn, there are some long-range electrostatic interactions in this protein. Both of these interactions likely serve as auto-inhibitors of alpha-Syn fibrillation. Methionine oxidation affects both electrostatic and hydrophobic long-range interactions in alpha-Syn. Finally, oxidation of methionines by H2O2 greatly inhibited alpha-Syn fibrillation in vitro, leading to the formation of relatively stable oligomers, which are not toxic to dopaminergic and GABAergic neurons., (2009 Elsevier B.V. All rights reserved.)

Several studies have shown that catecholamines can inhibit the fibrillation of alpha-synuclein (alpha-Syn), a small presynaptic protein whose aggregation is believed to be a critical step in the etiology of Parkinson's disease and several other neurodegenerative disorders. However, the mechanism of this inhibition is uncertain. We show here that substoichiometric concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC), a normal product of the metabolism of dopamine, can inhibit the fibrillation of alpha-Syn, due to non-covalent binding of DOPAC to alpha-Syn monomer. Intriguingly, the presence of alpha-Syn accelerates the spontaneous oxidation of DOPAC, and the oxidized form of DOPAC (the quinone) is responsible for the fibrillation inhibition. In addition, the presence of DOPAC leads to the oxidation of the methionine residues of alpha-Syn, probably due to the H(2)O(2) production as a by-product of DOPAC oxidation. The lack of fibrillation results from the formation of stable oligomers, which are very similar to those observed transiently at early stages of the alpha-Syn fibrillation. A possible explanation for this phenomenon is that DOPAC stabilizes the normally transient oligomers and prevents them from subsequent fibril formation. The analysis of the alpha-Syn Y39W variant suggests that DOPAC binds non-covalently to the same N-terminal region of alpha-Syn as lipid vesicles, probably in the vicinity of residue 39. In contrast to the compounds with 1,2-dihydroxyphenyl groups (DOPAC and catechol), their 1,4-dihydroxyphenyl isomers (hydroquinone and homogentisic acid) are able to modify alpha-Syn covalently, probably due to the less steric hindrance in the Michael addition.