1,721,863 research outputs found
Investigating Crystallization Tendency, Miscibility and Molecular interactions of drug-polymer systems for the development of amorphous solid dispersions
No full textThis project aims to characterize the crystallization tendencies, miscibility and molecular interaction in drug-polymer systems of poorly soluble drugs and correlate it with the performance of prepared or reported SDs (solid dispersions). Crystallization tendencies of five different drugs [i.e. Curcumin (CUR), indomethacin (IND), flutaminde (FLU), dipyridamole (DIP), griseofulvin (GRI)] in absence and presence of four different polymers [i.e. polyethylene glycol (PEG), eudragit EPO (EPO), hydroxypropyl methylcellulose (HPMC) and polyvinyl pyrrolidone (PVP)] in various drug-polymer ratios were determined by using modulated differential scanning calorimetry (MDSC). Thermal analysis i.e. glass transition temperature (Tg), crystallinity and melting point depression along with theoretical calculations such as solubility parameter were performed to study drug polymer miscibility. Molecular interactions were predicted by using Tg deviations and molecular modeling. Physical states of drug in the SDs were characterized by X-ray diffraction (XRD) and MDSC. IR (Infrared) and Raman were used in selected systems (i.e. CUR, DIP and GRI systems) to explore the role of drug polymer interactions in amorphization of SDs. Dissolution studies using USP apparatus II and physical stability study at room temperature were performed for selected systems. Based on the absence and presence of endothermic and exothermic peaks (heat-cool-heat cycle) in MDSC, the crystallization tendency of pure drugs was categorized as low, moderate and high. In presence of selected polymers, crystallization tendency of all the drugs can be modified albeit high polymer concentration was required for drugs with high crystallization tendency i.e. DIP and GRI (> 50%w/w). Polymers showing greater effect on crystallization tendency of drugs were found to have higher drug-polymer miscibility and stronger molecular interactions. For example, FLU- PVP system showed good miscibility and no remarkable Tg deviation. This is reflected in its ability to change the crystallization tendency of FLU. Further, the results correlated well with the physical state, dissolution and stability of prepared/reported SDs. The developed approach has significant potential to be a rational screening method for the development of amorphous SDs.ProQuest Traditional Publishing Optionxxiii, 130 page
Qualitative and Quantitative Methods to Determine Miscibility in Amorphous Drug-Polymer Systems
No full textAmorphous drug–polymer systems or amorphous solid dispersions are commonly used in pharmaceutical industry to enhance the solubility of compounds with poor aqueous solubility. The degree of miscibility between drug and polymer is important both for solubility enhancement as well as for the formation of a physically stable amorphous system. Calculation of solubility parameters, Computational data mining, Tg measurements by DSC and Raman mapping are established traditional methods used to qualitatively detect the drug–polymer miscibility. Calculation of Flory–Huggins interaction parameter, computational analysis of X-Ray Diffraction (XRD) data, solid state Nuclear Magnetic Resonance (NMR) spectroscopy and Atomic Forced Microscopy (AFM) have been recently developed to quantitatively determine the miscibility in amorphous drug–polymer systems. This brief review introduces and compiles these qualitative and quantitative methods employed in the evaluation of drug–polymer miscibility. Combination of these techniques can provide deeper insights into the true miscibility of the drug–polymer systems
Power Supply Noise Reduction for At-Speed Scan Testing in Linear-Decompression Environment
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
[[alternative]]The Study of Blended Course Learning Satisfactions of the Civil Service in the Republic of China
No full text[[abstract]]National Taiwan Normal University Graduate Institute of Political Science
The Study of Blended Course Learning Satisfactions of the Civil Service in the Republic of China
Student: Meng Fan-Tsung Advisor: Huang Jen-Chieh
Abstract：
The purpose of this research is to evaluate the satisfactions of “Blended Course Learning of Civil Servants in the Republic of China”. In order to achieve the research purposes, a learning satisfaction questionnaire for Blended Course was established. The items of the questionnaire include not only“Individual Basic Information”, but also some scales for study tools such as “Questionnaire for Overall Satisfactions”, “Questionnaire for Computer Competence”, “Personality Traits” and so on.
This research is targeted on 660 participants from 10 classes of 22 blended courses in 2005 at the Civil Service Development Institute. Totally 556 questionnaires were delivered, while 452 of which were returned with 53 invalid. As a result, the number of effective questionnaires is 399, and the effective returns-ratio is 71.76%. All the data were statistically analyzed via SPSS 10 to obtain these research conclusions, which will provide valuable information for the promotion and further study of the development of blended learning in the future.
8 major results found in this research are as follows:
1. The participants with different backgrounds existed no significant differences regarding to the issue of the“Designs of blended course learning in contributing to the achievement of the course goal”.
2. The population background variations partly significantly correlated to the computer attitudes of computer anxiety, computer confidence, computer usefulness, computer competence and on-line learning satisfactions, while no significantly correlated with the computer attitudes of computer liking and blended learning satisfactions.
3. Participants with internal control personality have more positive computer attitude.
4. Participants with positive computer attitude have higher satisfactions with on-line learning and blended learning.
5. Participants with internal control personality have better computer competence and higher satisfactions of blended learning; the participants with better computer competence also have higher satisfactions of blended learning.
6. The satisfaction of on-line learning or blended learning is influenced mainly by computer competence of participant.
7. The participants with different studying motives have no significant differences in on-line learning or blended learning.
8. Participants’ backgrounds and their studying motives have apparent reciprocation in on-line learning satisfactions.
According to the study results and discussions, suggestions were proposed to the following issues, these include: training course participants (attendees), on-line course and man-machine interface, planning of blended course learning, related government departments as well as relevant research in the future.
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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