1,303 research outputs found
Development & application of UV-visible microspectrometry to solid phase organic chemistry
No full textThe development and initial testing of a custom built UV-Visible microspectrometer for the analysis of materials supported on resins at the single-bead level is described with qualitative, quantitative and time-resolved UV-Vis spectroscopy being demonstrated with a variety of resins and supported chromophores. On-bead UV-Vis spectroscopy was extended to a variety of applications including the development of fibre-optic pH sensors utilising indicator dyes covalently attached to macroporous controlled pore glass beads and procedures for the attachment of carboxyl- and aniline-functionalised dyes to glass beads and for interfacing a single sensor bead to a UV-Vis spectrometer are described. Analysis of solid-supported chromophoric metal ligands was conducted for the detection and assessment of solid-supported tripeptides with high affinity for Cu, Ni and Co from a combinatorial “split-and-mix” library. The affinity of the various actively binding peptide sequences were estimated by quantifying the amount of chromophore produced within individual beads when exposed to an appropriate staining regent. On-bead e.e. determination of polystyrene-supported leucine and phenylalanine was also demonstrated by parallel kinetic chiral resolution using pseudoenantiomeric chromophore probes, followed by on-bead UV-Vis microspectrometric quantification of the attached probes. The e.e. measurement was conducted without the need for cleavage of the substrates from the resin at any stage and was successful even with low resin loadings.</p
Digital Media and Stress: The Cost of Caring 2.0
No full textThis research explores the relationship between the use of digital media and stress. Based on the findings of a national, probability sample of adults in the United States, the use of digital media was not directly associated with higher levels of psychological stress. Some uses of digital media were associated with lower levels of perceived stress for women but not for men. However, the evidence suggests that, for men and women, digital media provides heightened awareness of network life events (AoNLE) in the lives of both close and more distant acquaintances. An awareness of undesirable, major life events in the lives of others can be a source of psychological stress; this is the cost of caring. Thus, the link between digital media and stress is indirect. We argue that the growth of digital media is related to changes in the structure of peoples’ personal communities that contribute to this trend. There has been a shift toward networks that offer persistent contact and pervasive awareness. Findings suggest that different mobile technologies, Internet technologies, and social media afford AoNLE for men and women, but women tend to report greater psychological stress than men, and they experience psychological stress from a wider range of AoNLE. We discuss explanations for the negative relationship between technology use and stress for women, as well as the implications of our findings for research on the use of digital media and psychological well-being, such as the relationship to social support, narcissism and empathy.Peer reviewe
Fibre optic pH sensors employing tethered non-fluorescent indicators on macroporous glass
No full textpH sensors were developed by covalently attaching para-Methyl Red and (4-carboxyphenyl)-Bromophenol Blue onto macroporous glass beads. The beads were integrated into a readily fabricated sensor assembly coupled to a fibre optic spectrometer. The sensor was shown to be durable and had a rapid response time compared to other fibre optic sensor devices and electrochemical pH meters
Resin bead micro-UV - visible absorption spectroscopy
No full textThe construction and design of a microscope coupled with a miniature UV-vis spectrometer is described. This was applied to the study of dyes linked to solid supports and displayed good correlation in spectral shape and λmax values when compared to the dyes in solution, as well as showing a linear relationship between dye loading and UV-vis absorbance. The spectral profiles of these dyes at various pH's were measured and used to determine the pK(a) of the dyes on the beads, which were compared with the pK(a) values of the dyes in solution, thus enabling the dye-loaded beads to act as pH sensors
Automated image analysis of polymer beads and size distribution
No full textSize analysis of polymer beads is currently carried out using instruments such as Coulter counters. Here, image analysis software was used to analyze digital pictures of polymer beads and determine size profiles. Analysis was automated to provide high throughput scanning of images, and results compared favorably with traditional laser diffraction measurements. The technique also enabled the roundness of the beads to be measured in order to assess the bead quality after polymerization and physical manipulation. This method enabled automated and high throughput characterization of beads
A Method for Metal/Protein Stoichiometry Determination Using Thin-Film Energy Dispersive X-ray Fluorescence Spectroscopy
Full text linkA convenient approach is proposed for the quantitation of elemental cofactors in proteins and the determination of metal/protein stoichiometry, on the basis of energy dispersive X-ray fluorescence spectroscopy (EDXRF). The analysis of proteins containing the metals Cu, Fe, Zn, and Ca and also the nonmetallic element P is shown as a demonstration of the generality of the method. In general, the reported method gives limit of detection (LOD) and limit of quantification (LOQ) values in the low ppm range and requires only a few microliters of protein sample at micromolar concentrations. Moreover, sample preparation does not require any digestion steps before the analysis. The expected metal/protein stoichiometry was observed for each protein analyzed, highlighting the precision and accuracy of the method in all the tested cases. Furthermore, it is shown that the method is compatible with multimeric proteins and those with post-translational modifications such as glycosylation
[[alternative]]The Peer Relationships of Adults with Mental Retardation in Shin-Lu Community Home
No full text[[abstract]]This research was intended to develop 'The Peer Relationships of Adults with Mental Retardation (PRAMR) Checklist' for exploring the current peer relationships of adults with mental retardation and to establish 'The PRAMR Modes' and developmental stages as well. Following were the three main research steps in this study.
1. Through reviewing literature, first drafts of 'The Context Inquiry of PRAMR' and 'The PRAMR Checklist' were drawn up and revised by two scholars and two practitioners in related field as the second drafts.
2. Each four experts and practitioners in the field were asked to evaluate the importance degrees and to extend their opinions on the second drafts. Based on the results of the above survey and the actual use of the drafts in interviews, it was then revised and reconstructed into 'The PRAMR Checklist'.
3. Using the second drafts of the PRAMR checklist, the researcher interviewed and observed adults with mental retardation and their significant others in the community home to explore the current peer relationships of adults with mental retardation and to establish 'The PRAMR Modes' and developmental stages.
The findings of the research were summarized as below:
1. 'The PRAMR Checklist' comprised four areas including 'influential factors of peer relationship', 'friendship- generating context', 'existing peer relationship' and 'peer relationship expected'.
2. There were no differences in peer relationships of adults with mental retardation amng variables of gender, age and duration in the community home. However, the severities of retardation, education level, oral language ability, community participation, working competence and family background showed significant differences in both quantities and qualities of peer relationships.
3. The differences of peer relationships in various situations were attributed by factors of site, people and activities.
4. Adults with mental retardation perceived peer relationships differently from significant others' perceptions. The former displayed more detailed description and expectation about the concepts of friendships than the latter.
5. There were inconsistent results from interviews and observations. Some adults with mental retardation 'eloquently' described their peer relationships during the interviews but performed withdrawal, shy, anxiety and confusion through direct observations. Whereas some others talking little about peer relationships in the interviews displayed active peer relationships during observation.
6. Five modes characterizing the PRAMR in the community home were 'solitary', 'dyad', 'chain', 'radiation' and 'network'.
7. Five developmental stages of the PRAMR in the community home were 'perceived existence', 'flat contact', 'close connection', ' conflict and hassel' and 'friendship ending'.
Low-end mass function of the Quintuplet cluster
No full textThe Quintuplet and Arches clusters, which were formed in the harsh environment of the Galactic Centre (GC) a few million years ago, have been excellent targets for studying the effects of a star-forming environment on the initial mass function (IMF). In order to estimate the shape of the low-end IMF of the Arches cluster, Shin & Kim devised a novel photometric method that utilizes pixel intensity histograms (PIHs) of the observed images. Here, we apply the PIH method to the Quintuplet cluster and estimate the shape of its low-end IMF below the magnitude of completeness limit as set by conventional photometry. We found that the low-end IMF of the Quintuplet is consistent with that found for the Arches cluster-Kroupa MF, with a significant number of low-mass stars below 1 M-aS (TM). We conclude that the most likely IMFs of the Quintuplet and the Arches clusters are not too different from the IMFs found in the Galactic disc. We also find that the observed PIHs and stellar number density profiles of both clusters are best reproduced when the clusters are assumed to be at three-dimensional distances of approximately 100 pc from the GC.National Research Foundation - Ministry of Science, ICT and Future Planning of Korea; International Cooperation and Exchange Program - National Natural Science Foundation of China (NSFC) [11450110400]SCI(E)[email protected]; [email protected]
The shaping of Lu Xun&amp;apos;s public image and his portrait images
No full textAfter Lu Xun published “A Madman&amp;apos;s Diary” (Kuangren riji) and “The True Story of Ah Q” (A Q zhengzhuan), through the active introduction by modern Korean mass media, Lu Xun enjoyed the highest popularity of all modern Chinese literary author in Korea Peninsula. “A Madman&amp;apos;s Diary” translated by Ryu Sooin, was published in the magazine Donggwang (The oriental light) in 1927. Yang Baekhwa&amp;apos;s translation of “The True Story of Ah Q” was serialized in The Chosun Ilbo (The Korea daily) in 1930. “Lu Xun and His Works” by Jeong Raedong, who conduct systematic criticism on Lu Xun&amp;apos;s literature, was published in The Korea Daily in 1931. Lu Xun was thus differentiated from the so‐called “Zhou Brothers” and claimed a place of his own as a representative Chinese writer. After that, Lu Xun&amp;apos;s various works were translated into Korean, and he was acknowledged as “a Chinese literary master” and “a world‐class writer” in the Korean literary world. Lu Xun&amp;apos;s literature was hence widely acknowledged. Lee Kwangsoo even created another character called “Park Seondal” based on the motif of “Ah Q.” With the development of mass media, people were eager to see Lu Xun&amp;apos;s personal image. In the 1930s, major Korean media, such as The Shin Dong‐a (The new East Asia), The Dong‐a Ilbo (The East Asia daily), The Chosun Ilbo (The Korea daily), The Maeil Sinbo (The daily report), Chokwang (The morning light) and Samcheonli (Three thousand miles), successively published Lu Xun&amp;apos;s portraits and photos, helping visualize Lu Xun&amp;apos;s image and making great contributions to shaping the public image of Lu Xun and his literature. Through these major media in Korea, Lu Xun&amp;apos;s works and his reputation became widely known, and his portrait images were also circulated. In February 1938, the Hwarang Garden Troupe staged the play The True Story of Ah Q. Considering the commercial nature of the theatre at that time, the public performance of The True Story of Ah Q indicates that Lu Xun and his works had achieved a solid foothold in the public mind. However, Korean people&amp;apos;s access to Lu Xun&amp;apos;s literature was blocked after March 1938, when Japanese imperialists imposed a blanket ideological clampdown. With the advent of liberation on August 15, 1945, the modern Korean public strongly needed Lu Xun&amp;apos;s life experience and literary spirit as enlightenment. Hence, translation and research of Lu Xun&amp;apos;s literary works became active again. In particular, in 1946, after the publication of The Collected Short Stories of Lu Xun (Volumes 1−2), jointly translated by Kim Kwangju and Lee Yongkyu, which included Lu Xun&amp;apos;s major works, Korean people were able to gain a more systematic access to Lu Xun&amp;apos;s literature. The inspirational value of Lu Xun&amp;apos;s literature was re‐ignited after Korea&amp;apos;s liberation and independence. Lu Xun was thus once again praised as “a literary giant” and “a great writer. © 2020 Brill Academic Publishers. All rights reserved
Control of Biological Responses by Isolated Synthetic Material Variables
Full text linkIt is well established that cells sense and respond to stimuli at the sub-micron and nanometre scale, a factor that must be considered in future biomaterial design. The understanding of how biological entities interact with material features at this scale is limited due to the limitations of material fabrication techniques that can readily isolate enrichment of a surface with a chemical group, whilst reproducibly controlling nanotopography and stiffness.
Polymer pen lithography (PPL), a nanotechnology that has advanced the technique of single probe nanolithography in combination with traditional microcontact printing, has since been introduced due to its capability of fabricating high throughput surface patterns over large surface areas (multiple cm2) in a short period of time.
In this work, PPL has been used as a powerful nanotechnique to fabricate reproducible surface nanofeatures with a size of 300 nm with various centre-to-centre distances using a range of chemicals as “inks” with presentation of pre-selected carboxyl and amino groups on appropriate surfaces as “papers”. These fabricated surfaces have been used to evaluate the isolated and combitorial effects of changes in surface chemistry and topography on mesenchymal stem cell and chondrocyte adhesion and phenotype in vitro. Carboxylic acid terminated nanoarrays with various centre-to-centre distance have been proven to induce mesenchymal stem cell towards chondrogenesis and hypertrophic chondrogenesis. In addition, the selected carboxylic acid terminated nanoarrays successfully promoted the maintenance of chondrogenic phenotype of articular chondrocytes over 3 experimental passages. Conversely, amino terminated nanoarrays with various centre-to-centre distance potentially supported mesenchymal stem cell differentiation towards adipogenesis.
In addition to understanding the role of surface chemistry on initial cell response, the in situ control of stiffness at a molecular level has been studied. A range of photoresponsive molecules were synthesised and incorporated within the hydrogel network. Preliminary cell-surface interactions were established with these hydrogels. The developed nanofabrication methodology and established parameters exhibited unprecedented control of cell morphology, differentiation and maintenance of phenotypes that has improved the fundamental understanding of mechanical signalling events
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