Glow Discharge Mass Spectrometric Determination of Selected Biological Species

Glow discharge mass spectrometry (GDMS) is widely used for trace elemental analysis of solid samples. A glow discharge source employs cathodic sputtering to release cathode species to the gas phase and subsequent collisional ionization of the sputtered species in the plasma. Ions representing the cathode material are differentiated by mass-to-charge values and then recorded by mass spectrometry. A pulsed radio frequency (RF) glow discharge time-of-flight mass spectrometry (GD-TOF MS) is employed in this study for its unique advantages, including the capability of direct analysis of nonconducting solids, temporal separation of ionization mechanisms, and the ability to acquire a complete spectrum within a single pulse cycle.;Although GD-TOF MS exhibits superior performance in direct solid analysis, its application to solution samples faces several problems arising from the solvent. In this study, analyte solutions are converted to dry residues on a conducting cathode surface involving the deposition of microliter volumes of analyte solution and subsequent drying in vacuum desiccator before conventional GDMS analysis. By this means, analytes including cysteine, glycyl-L-histidyl-L-lysine copper (GHK-Cu) complex and iodinated organic compounds are successfully sampled by GD plasma for mass spectrometric measurement.;Cysteine analysis is a follow-up study based on previous findings in this lab. Cysteine residues analyzed by the current GDMS system reveals a characteristic ion at m/z 76 in the afterpeak regime. However, the cysteine residue prepared previously in a Cu reservoir only produces a very weak characteristic ion signal and this ion signal dissipates quickly over time, indicating significant sample loss in the sputtering process. So, a new sample preparation method was introduced, involving adding a layer of paper material on top of the cathode surface. The layer is designed to provide a better support to the solution residue. In particular, hydrophilic membrane filter as the layer material allows even distribution of the cysteine solution added, and is expected to trap the residue inside the pores as well as on the membrane surface. Residue prepared on the membrane shows superior performance in that an intense and long-lasting cysteine fragment ion signal can be obtained. However, the reproducibility of this method needs improvements, as can be seen from the quantitative results. Comparison of GD results between cysteine and deuterated cysteine fails to prove that the cysteine fragment at m/z 76 is produced from loss of carboxylic acid group.;GDMS analysis of GHK-Cu complex was completed with dry residues formed on a silver cathode. Residue analysis in a pulsed plasma only produces a distinct Cu+ ion signal regarding the analyte in the afterpeak regime. No information regarding the peptide structure was detected. However, the stoichiometric ratio of Cu element to the peptide is known (1:1), enabling the quantification of copper peptide to be completed with Cu measurement. Before quantification, factors including power, pressure, pulse width, duty cycle and sampling distance were evaluated for their influences on the Cu+ ion signal and optimal conditions were located for the best sensitivity. Subsequently, quantification was completed with GHK-Cu residues prepared from five concentrations and the calibration curve obtained shows good linearity.;Iodinated organic compounds, specifically three thyroid hormones (THs) were analyzed by GDMS as well. Because iodine has a high ionization potential (10.45 eV), a helium plasma was established within the GDMS system and its efficiency in sputtering and ionization was proved in a comparison with argon plasma for the analysis of blank Cu and triiodothyronine (T3). Analysis of THs residues in a pulsed helium plasma reveals a similar pattern and only an I+ ion signal found in the afterpeak is of sufficient intensity for further analysis. Quantification of diiodothyronine was demonstrated as an example and the calibration curve shows good linearity. Cross comparison among the three THs reveals that iodine atoms found at different positions within organic molecules are ionized to the same extent in GDMS

Application of Radial Categories to the Second Language Learning of Chinese Learners

As a relatively new discipline which raised in the 20th century Cognitive linguistics has gradually become the mainstream in the development of recent decades. In cognitive linguistics some major theories related with language teaching and learning are construal, categorization, encyclopedic knowledge, symbol, metaphor, and metonymy. In this paper being based on the theory of radial categories the author turns attention to second language learning to explore implications of performance of vocabulary, morphemes, grammar rules, phonology, and intonation in radial categories in the second language learning

A JavaScript and PHP EPUB reader web application

EPUB is one of the most popular ebook formats. It is supported by many e-Readers, such as Apple’s iBooks, BlackBerry Playbooks, Sony Reader, Kobo eReader, Amazon Kindle Fire, and the Mozilla Firefox add-on EPUBReader. In this report, we describe our implementation of a JavaScript and PHP EPUB reader web application. This web application allows users to read the EPUB format books easily across multiple devices without any specified platform lock-in. Our application provides an EPUB library. When a user logs in, he can borrow an EPUB book from the library and save into his own bookshelf, then choose any one from his own bookshelf to read. Our application tracks where a user has been reading so users can easily pick up where they left off if they leave the application

An Attitudinal Analysis of English Song Discourse from the Perspective of Appraisal Theory

Appraisal theory is a new development of the interpersonal meaning in systematic functional linguistics. In recent years, the appraisal theory has been widely used in different genres to study whether and how slightly different appraisal methods are used in them. However, analysis of English song discourse with the appraisal theory is rare. Therefore, based on the attitude meaning in the appraisal theory the author analyzes several English song discourses. Through analysis of characteristics of the distribution of attitude resources in the English discourse it aims to find language feature in the English song discourse so as to make readers understand the emotion expressed by the author of the song discourse and the importance of the attitude meaning of the appraisal theory in building interpersonal relations between the author of the song discourse and readers

The Transition from Comprehensive to Analytical Characteristics of English Language

English belongs to the Indo-European language family. It is a language that achieves meaning expression through its own form of inflection, focusing on form, and it is one kind of comprehensive language. Analytical language expresses grammatical meaning through function words, word order, and so on. With the development of language, English has a tendency to develop from comprehensive language to analytical language. In this study, it explains the transitional characteristics of English language from comprehensive characteristics to analytical characteristics from following aspects: reduces or even disappears of English  morphological change; the ability of English vocabulary meaning expansion; the multi-use of function words; the powerful grammatical function of the article; the fusion of English and Chinese language; the Chinese loanword in English;  the Syntactical phenomenon of English and Chinese language, the complexity of English word formation, the theme-highlight sentence pattern

Genomic, Evolutionary and Functional Analyses of Diapause in Drosophila Melanogaster

Understanding the genetic basis of adaptation has been and remains to be one major goal of ecological and evolutionary genetics. The variation in diapause propensity in the model organism Drosophila melanogaster represents different life-history strategies underlying adaptation to regular and widespread environmental heterogeneity, thus provides an ideal model to study the genetic control of ecologically important complex phenotype. This work employs global genomic and transcriptomic approaches to identify genetic polymorphisms co-segregating with diapause propensity, as well as genes that are differentially regulated at the transcriptional level as a function of the diapause phenotype. I show that genetic polymorphisms co-segregating with diapause propensity are found throughout all major chromosomes, demonstrating that diapause is a multi-genic trait. I show that diapause in D. melanogaster is an actively regulated phenotype at the transcriptional level, suggesting that diapause is not a simple physiological or reproductive quiescence. I also demonstrate that genetic polymorphisms co-segregating with diapause propensity, as well as genes differentially expressed as a function of diapause are enriched for clinally varying and seasonal oscillating SNPs, supporting the hypothesis that natural variation in diapause propensity underlies adaptation to spatially and temporally varying selective pressures. In addition to global genomic and transcriptomic screens, I also performed functional analysis of one candidate polymorphism on the gene Crystalllin, which represents an intersection of multiple global screens related to seasonal adaptation. I show that this polymorphism affects patterns of gene expression and a subset of fitness-related phenotypes including diapause, in an environment-specific manner. Taken together, this work provide a holistic view of the genetic basis of a complex trait underlying climatic adaptation in wild populations of D. melanogaster, linking genetic polymorphism, gene regulation, organismal phenotype, population dynamics and environmental parameters

Drivers of Consumers Online Purchasing Intention in China on Singles’ Day

Purpose – The purpose of the present study is to understand the drivers of Chinese consumers online purchase intention on Singles’ Day so as to aid e-retailers in working out marketing programs that can help increase sales on that day. Methodology – Data were collected from 214 Chinese consumers who have online purchase experience on Singles’ Day via snowball and convenience sampling. SPSS statistics 20 was employed to analyse the collected data. Findings – The results show that consumers online purchase intention is positively related to the proposed four drivers, namely, promotion, e-store atmosphere, word of mouth, and advertising and consumption rituals with either direct or indirect relationship with mediators such as perceived value, shopping enjoyment, impulsive buying orientation, and browsing. More specifically, advertising and consumption exhibit a stronger influence among all drivers. Practical implications – Online retailers should consider the importance of providing authentic promotion campaigns to improve consumers’ perceived value. Besides, enjoyable e-store design and optimal navigability could stimulate consumers’ impulsive buying orientation. Moreover, retailer could encourage and reward those old consumes who provide others with valuable word of mouth message. Additionally, greater effort is suggested to make on both outdoor and social media advertising when Singles’ Day is approaching. Originality/Value – In spite of quite a number of existing researches done in the online shopping consumer behaviour field, little research has addressed drivers of consumers online purchase intention on Singles’ Day. The empirical evidence of this study will contribute to the literature in online shopping purchase intention