8,820 research outputs found
Enantioselective capillary electrophoresis : fundamental aspects and application to the "in vitro" assessment of CYP3A4 mediated ketamine N-demethylation
Get PDFA large number of pharmaceutical substances are administered as racemates, consisting of two enantiomers with typically different pharmacodynamic and pharmacokinetic profiles. Thus, stereoselective analysis is important in drug development, therapeutic drug monitoring and research. Chiral separation by chromatographic methods such as HPLC and GC require expensive stationary phases. In contrast, in capillary electrophoresis (CE), enantioselective separation can be obtained using one or several chiral selectors which are added to the background electrolyte. Separation of enantiomers is based on different binding affinities with the enantiomers and/or different migration velocities of the formed analyte-selector complexes. High resolution can be achieved by varying type and concentration of chiral selector as well as buffer properties (pH, ionic strength, other additives etc.). Typical chiral selectors are neutral or charged cyclodextrins, proteins and bile acids. The simplicity of the technique makes enantioselective CE an attractive, promising and economic methodology for drug and metabolite analysis in pharmaceutical preparations, body fluids, tissues and microsomal preparations.
In the first part of this thesis, fundamental aspects of enantioselective CE were investigated using computer simulation. Dynamic computer simulators provide insight into the buffer system and improve understanding of the electrophoretic separation process. Simulation allows to predict proper separation and detection conditions for analytes prior to experiments. Using an extended version of the dynamic computer simulator GENTRANS, the interaction of methadone and its main metabolite EDDP with neutral chiral selectors were simulated. Experimentally determined complexation constants and mobilites of the formed complexes were employed as additional input parameters. Simulated electropherograms were qualitatively in good agreement with the experimental results.
In the second and third parts of the thesis, enantioselective CE was applied to study ketamine metabolism in an off-line study. Ketamine is a chiral phencyclidine derivative used in anesthesia. In vitro and also in vivo studies showed a higher affinity for the NMDA-receptors, higher anesthetic potency and shorter recovery time for S-ketamine compared to R-ketamine. The aims in this project were to characterize the kinetics of CYP 3A4 mediated ketamine N-demethylation in vitro including KM, Vmax and to investigate the stereoselective metabolism of this pathway. Furthermore, the inhibition kinetics of this pathway by ketoconazole, a potent CYP3A4 inhibitor, was investigated. Results showed a higher formation rate for S-norketamine after incubation of racemic ketamine as well as incubation of the single enantiomers. Data obtained in the absence of ketoconazole revealed that the N-demethylation occurred stereoselectively. Inhibition kinetics by ketoconazole fitted best to a one-site competitive model and no stereoselectivity could be demonstrated.
In the forth and final part of this thesis, an on-line method was developed to investigate the in vitro N-demethylation of ketamine via CYP3A4, with the incubation performed in-capillary with subsequent electrophoretic separation and detection of the ketamine enantiomers. Kinetic parameters obtained compared well with those of the off-line study mentioned above and the metabolic step was stereoselective, confirming the results of the off-line assay. After additional improvements, the in-capillary method should be widely applicable to assess enzymatic activity in a fast, low-cost and automated way
Kwan Life
Get PDFKwan Life es un empresa recreo deportiva que se destaca por sus dos líneas de trabajo, en su primer línea destaca toda la parte deportiva, donde se ofrece una variedad de deportes como lo son ultimate, futbol, artes marciales, gimnasia artística, exploración motriz y entrenamientos personalizados mientras que en su segunda línea trabaja toda la parte recreativa a través de las caminatas eco turísticas, campamentos y la educación experiencial.
El objetivo de Kwan Life como empresa es promover los beneficios que brinda el deporte y la recreación por medio de sus dos líneas manteniendo una vida activa y saludable. Kwan Life cuenta dos sedes propias ubicadas en Kennedy y Usme centro por lo cual es la población objetivo de Kwan Life y la cual se beneficiará principalmente de los programas que se ofrecen.
De las principales características por las que se destaca Kwan Life es por su bajo costo para acceder a cada uno de los programas que se ofrecen, por su alta calidad en la prestación del servicio y por su formación en valores basadas en el pensamientos humanístico de Tomas de Aquino.Kwan Life is a sports recreation company that stands out for its two lines of work, in its first line the entire sports part stands out, where a variety of sports such as ultimate, soccer, martial arts, artistic gymnastics, motor exploration and personalized trainings while in his second line it works all the recreational part through ecotourism walks, camps and experiential education.
The objective of Kwan Life as a company is to promote the benefits offered by sports and recreation through its two lines, maintaining an active and healthy life. Kwan Life has two of its own offices located in Kennedy and Downtown Usme, which is why it is the target population of Kwan Life and which will mainly benefit from the programs offered.
One of the main characteristics for which Kwan Life stands out is its low cost to access each of the programs offered, its high quality of service provision and its training in values based on the humanistic thoughts of Tomas of Aquino.Profesional en Cultura Física, Deporte y RecreaciónPregrad
The interaction between ICT and human activity-travel behavior
No full textThe interaction between information and communication technologies (ICT) and human activity-travel behavior has been an important theme in transportation research in recent years. Researchers have recognized that an increase in the use of ICT may lead to changes in the location, timing and duration of people’s activities, and the widespread use of ICT will likely be associated with new patterns of activity and travel in space–time (Kwan, 2002 and Dijst, 2004 M. Dijst, ICT and accessibility: an action space perspective on the impact of new information and communication technologies. In: M. Beuthe, V. Himanen, A. Reggiani and L. Zamparini, Editors, Transport Developments and Innovation in an Evolving World, Springer, Berlin (2004), pp. 27–46.Dijst, 2004). Analyses of these patterns could provide part of the empirical basis and/or behavioral foundation for enhancing our understanding of the interaction between ICT, activity-travel behavior and urban form
CUHK electronic theses & dissertations collection
No full textKwan, Ho Ling Godiva.Thesis M.Phil. Chinese University of Hong Kong 2015.Includes bibliographical references (leaves 65-71).Abstracts also in Chinese.Title from PDF title page (viewed on 20, September, 2016)
Altar Sembahyang untuk Dewi Kwan Im pada Rumah Masyarakat Tionghoa Buddha di Medan : Kajian Terhadap Artefak, Kegiatan, dan Gagasan
No full textMasyarakat Tionghoa Buddha Di Medan : Kajian Terhadap Artefak, Kegiatan, Dan Gagasan”.The purpose of this research is to describe the artifacts, activities and ideas on the worship altar of the goddess Kwan Im at Medan Chinese Buddhist society home.The methods to gathering the data do in field works, and then applied in: interview, observation, recording the activities at worship altar, observe as participant observer, and library research.The author uses the theory of Barthes’s semiotic theory to describe ideas of worship altar of the goddess Kwan im atMedan Chinese Buddhist society home, and theory three shape of culture by J.J Hoenigman to describe the artifacts, activities and ideas on the worship altar of the goddess Kwan Im at Medan Chinese Buddhist society home. In the altar Dewi Kwan Im contained artifacts such as statues (sculptures) Buddha as a symbol of Buddhahood and respect the noble values of the Buddha, lamps and oil as symbolic of wisdom and compassion, water as a symbol of pure and clean, incense symbolizes the act purify the mind, music that contains mantra da bei cou, fruits symbolize the fruits of act or success for the efforts that have been implemented, fresh fruit laid out are apples, oranges, pineapple, flowers are used to express a feeling grateful to the Buddha, fresh flowers were laid is chrysanthemums, lilies, orchids, narcissist, and a bamboo stalk.On the altar Dewi Kwan Im also conducted prayers, prayers when move from house to new house, clean the altar and statues using flower waterIn ideas, Chinese society who embraced Mahayana Buddhist usually put altar prayer of goddess Kwan Im at home as a means of worship and ask for safety and health.The title of this paper is “Altar Sembahyang Untuk Dewi Kwan Im Pada Rumah Masyarakat Tionghoa Buddha Di Medan : Kajian Terhadap Artefak, Kegiatan, Dan Gagasan”.The purpose of this research is to describe the artifacts, activities and ideas on the worship altar of the goddess Kwan Im at Medan Chinese Buddhist society home.The methods to gathering the data do in field works, and then applied in: interview, observation, recording the activities at worship altar, observe as participant observer, and library research.The author uses the theory of Barthes’s semiotic theory to describe ideas of worship altar of the goddess Kwan im atMedan Chinese Buddhist society home, and theory three shape of culture by J.J Hoenigman to describe the artifacts, activities and ideas on the worship altar of the goddess Kwan Im at Medan Chinese Buddhist society home. In the altar Dewi Kwan Im contained artifacts such as statues (sculptures) Buddha as a symbol of Buddhahood and respect the noble values of the Buddha, lamps and oil as symbolic of wisdom and compassion, water as a symbol of pure and clean, incense symbolizes the act purify the mind, music that contains mantra da bei cou, fruits symbolize the fruits of act or success for the efforts that have been implemented, fresh fruit laid out are apples, oranges, pineapple, flowers are used to express a feeling grateful to the Buddha, fresh flowers were laid is chrysanthemums, lilies, orchids, narcissist, and a bamboo stalk.On the altar Dewi Kwan Im also conducted prayers, prayers when move from house to new house, clean the altar and statues using flower waterIn ideas, Chinese society who embraced Mahayana Buddhist usually put altar prayer of goddess Kwan Im at home as a means of worship and ask for safety and health.Skripsi Sarjan
Using theory of learning and awareness to bring about learning through a school-based environmental field project
Get PDFA school-based environmental field project 'What Happens Around You and Your School Area?' was designed under the School-based Curriculum Project Scheme (2001-2002) supported by the Hong Kong Education Manpower Bureau (formerly the Education Department). This school-based environmental field project, with heavy inclusion of environmental elements, was designed in the form of issue-based field inquiry based on student-centred learning to encourage subsequent meaningful learning activities such as group discussion, role-playing exercises and photograph exhibition in class. The field project possesses distinctive geographical and environmental characteristics of the school surrounding environments to bring about meaningful learning among students who study in a local standard new town secondary school in Hong Kong. This paper aims to share this field project experience of designing meaningful issue-based field inquiry using the theory of learning and awareness (Marton & Booth, 1997) to open up the space of learning for students (Marton et al., 2004; Runesson & Marton, 2002). Also based on the framework of educational and environmental ideologies (Fien, 1993), the intended learning outcomes of the field project are to empower students to become active small environmentalists (Kwan, 1995) who are well prepared in terms of geographical and environmental knowledge, skills and values. © 2004 T. Kwan & E. Chan.published_or_final_versio
Xiang mu tou biao bo yi
No full textKwan, Chi Chung.Thesis M.Phil. Chinese University of Hong Kong 2014.Includes bibliographical references (leaves 67-70).Abstracts also in Chinese.Title from PDF title page (viewed on 02, December, 2016).Kwan, Chi Chung
Minority Media Production Practices and Cultural Citizenship in Hong Kong
No full textChong, Cheung Kwan Cindy.Thesis Ph.D. Chinese University of Hong Kong 2016.Includes bibliographical references (leaves ).Abstracts also in Chinese.Title from PDF title page (viewed on …)
Field investigation of deformation characteristics and stress mobilisation of a soil slope
Get PDFStress mobilisation and deformation of a slope are important for engineers to carry out reliable design of retaining systems. However, most case histories reported mainly on the response of pore-water pressure (PWP), whereas knowledge about the stress-deformation characteristics of slope is limited. In this study, a saprolitic soil slope was instrumented to monitor not only the responses of PWP but also horizontal stress and horizontal displacement. To assist in the interpretation of field data, a series of laboratory tests was conducted to characterise the volume change behaviour of soil taken from the site, under the effects of both net stress and suction. During a rainstorm event when positive PWP built up, a remarkably large displacement of 20 mm was recorded between 5.5 and 6 m depths, and the top 5 m of the slope exhibited translational down-slope movement. This caused an increase in effective horizontal stress by 350%, which reached a peak value close to 40% of an effective passive stress. During the subsequent dry season when suction was recovered, an up-slope rebound of 10 mm was recorded. Comparison of field and laboratory data reveals that the rebound was attributed to suction-induced soil shrinkage. This rebound led to a decrease in the effective horizontal stress previously built up during the storm event
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