Circadian clocks are composed of molecular oscillators and are found in most eukaryotes and some prokaryotes. The fungus Neurospora crassa is a leading model for studying the clock. In N. crassa, the well-described FRQ/WCC Oscillator (FWO) consists of a molecular feedback loop involving the negative element FRQ, the blue-light photoreceptor WC-1, and WC-2. WC-1 and WC-2 form a complex called WCC, which functions as the positive element in the feedback loop. The FWO is considered to be the core oscillator regulating overt rhythmicity. However, several labs have shown that rhythms can persist in the absence of a functional FWO under certain growth conditions and genetic backgrounds, suggesting the presence of additional oscillators in the cell. Using genetic approaches to identify components of these putative oscillators, we uncovered a mutant strain, called light-mutant 1 (LM1) that is robustly rhythmic in constant light, and in strains carrying deletions of FWO components; both of which are conditions that abolish FWO function. The oscillator (called the Light Mutant Oscillator, LMO) revealed in the LM1 mutant strain meets two of the three criteria for a circadian oscillator. The LMO has a free running period of ~ 24h, and it is temperature-compensated. However, while the LMO can respond to light cues, WC-1 is required for circadian entrainment to 24-h light cycles. The response of LM1 cells lacking the circadian blue-light photoreceptor WC-1 to blue-light suggested that alternate light inputs function in LM1 mutant cells. I show that the blue light photoreceptors VIVID and CRY compensate for each other, and for WC-1, in LMO light responses. Importantly, I show that deletion of the cryptochrome (cry) gene abolishes rhythmicity in an LM1 strain, providing evidence for a role for CRY in the clock mechanism. The LM1 mutation is recessive, suggesting loss of function. Therefore, we hypothesize that the LM1 gene encodes a protein that negatively regulates the activity of the LMO. Our mapping and sequencing data have placed the LM1 mutation on the left arm of chromosome I, near the mating type locus; however, the identity of the mutated gene remains elusive.

Chez la majorité des être vivants des systèmes d’horloge circadiennes (=environ 24h) se sont développés afin d’anticiper les variations journalière de l’environnement. Ces horloges endogènes reposent sur des oscillateurs moléculaires régulant l’expression circadienne de nombreux gènes. Récemment il a pu être montré que des régulations post-transcriptionnelles jouaient un rôle majeur dans la rythmicité de nombreux gènes.Dans la lignée cellulaire hypophysaire GH4C1, nous avons étudié un mécanisme post-transcriptionnel impliquant des corps nucléaires appelés paraspeckles. L’élément principal des paraspeckles est le long ARN non codant (lncRNA) Neat1 auquel s’associe des protéines de liaison aux ARNs. Il a été montré que les paraspeckles ont la capacité de retenir dans le noyau des ARNs, en particulier ceux qui présentent des motifs IRAlu dans leur région 3’ non codante. Nous avons montré que dans les GH4C1, les paraspeckles se forment avec une rythmicité circadienne. Grâce à la mise au point d’une méthode dite de RNA pull-down, permettant l’étude des cibles ARNs d’un lncRNA, nous avons montré que les paraspeckles s’associent et induisent la rétention nucléaire circadienne d’ARNs hypophysaires. Chez ces ARNs nous avons montré l’absence de motifs IRAlu. L’étude d’ARN cibles des paraspeckles a montré que la reconnaissance par les paraspeckles pouvait se faire par des motifs localisés hors de la région 3’ non codante, et que plusieurs séquences dans un même ARN pouvaient participer à la liaison aux paraspeckles.Cette étude nous a donc permis d’identifier un nouveau mécanisme post-transcriptionnel régulant l’expression circadienne de gènes dans les cellules hypophysaires. / Most living organisms have developed circadian (=close to 24h) clock to face daily changes in their environment. Those clocks rely on molecular oscillators to drive the circadian expression of many genes. In the pituitary cell line GH4C1, we studied a post-transcriptional mechanism involving nuclear bodies called paraspeckles. Paraspeckles main element is the long non-coding RNA Neat1 to which several RNA binding proteins are associated. Paraspeckles have been shown to retain RNAs in the nucleus, in particular RNAs that display an IRAlu element in their 3’ translated region (3’UTR).In GH4C1, we showed that paraspeckles display a circadian rhythm of formation. We created the RNA pull-down method, which allows to purify a lncRNA with all its RNA targets, This allowed us to demonstrate that paraspeckles induce the circadian nuclear retention of several endogenous RNAs. Finally, we showed the absence of IRAlu elements in those RNAs. The study of tree target RNAs of paraspeckles showed that elements localized out of the 3’UTR could be involved in the recognition by paraspeckles, but also that several elements could be necessary to induce the RNA retention by paraspeckles.To conclude, this study allowed us to identify a new post-transcriptional mechanism regulating the circadian expression of pituitary genes.

by Chan Ngan-Yung, Juno, Yuen Da-Wai, David. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 137-141). / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / LIST OF FIGURES --- p.viii / LIST OF TABLES --- p.ix / ACKNOWLEDGEMENT --- p.x / INTRODUCTION --- p.1 / Objectives of the Research --- p.1 / Scope of Work --- p.4 / Research Methodology --- p.5 / Literature Survey --- p.6 / Sources for the Adopted Theoretical Framework --- p.6 / Local Researches on Timepieces industry --- p.7 / Statistical Information --- p.7 / INDUSTRY AND COMPETITIVE ANALYSIS --- p.9 / Dominant Economic Characteristics of the Industry Environment --- p.9 / Scope of Competitive Rivalry --- p.9 / Market Size --- p.10 / Market Growth Trend by Watch Type --- p.10 / Market Growth Trend by Geographical Location --- p.13 / Market Trend Towards Higher-end Products --- p.18 / Stage in Product Life Cycle --- p.20 / Seasonal Market Demand Pattern --- p.22 / Customer Needs and Product Segments --- p.22 / Customer Groups --- p.23 / Degree of Vertical Integration --- p.24 / Ease of Entry or Exit --- p.25 / Technology and Innovation --- p.25 / Industry Structure --- p.26 / Cost Structure --- p.27 / Scale Economies --- p.28 / Experience Curve Effect --- p.29 / Capacity Utilization --- p.29 / Industry Profitability --- p.29 / Driving Forces Analysis --- p.33 / Decline in Long-term Industry Growth Rate --- p.34 / Shortening Product Life Cycle --- p.34 / Consumers Moving Up-market --- p.34 / Competitive Forces and their Strategic Implications --- p.35 / Rivalry Among Existing Competitors --- p.35 / Threat of Product Substitution --- p.38 / Potential Entry of New Competitors --- p.39 / Bargaining Power of Suppliers --- p.39 / Bargaining Power of Buyers --- p.40 / Strategic Implications --- p.40 / Strategic Group Mapping --- p.41 / Competitor Analysis --- p.45 / Switzerland --- p.45 / Japan --- p.49 / Taiwan --- p.56 / Korea --- p.60 / "Thailand, Singapore and Other Asian Countries " --- p.62 / Key Success Factors of the Industry --- p.67 / Industry Prospects and Overall Attractiveness --- p.67 / SITUATION ANALYSIS FOR HONG KONG AND THE PRC TIMEPIECES INDUSTRY --- p.72 / Situation Analysis of Hong Kong's Timepieces industry --- p.72 / Evaluation of the Present Strategy --- p.72 / SWOT Analysis --- p.77 / Potential internal strengths --- p.77 / "Core competencies in marketing, prompt delivery and flexibili " --- p.77 / Well thought of by buyers . --- p.79 / Proximity to an abundant cheap labor market --- p.79 / Proximity to a large consumer market with high growth potenti --- p.80 / Potential internal weaknesses --- p.81 / Over-dependence on several traditional markets --- p.81 / Lagging behind in production technology --- p.81 / Lack of key skills in producing movement and module parts --- p.84 / Over-dependence on OEM sales --- p.85 / Shortage of labor and experienced product designers --- p.85 / Rising labor and land costs --- p.85 / Political uncertainty --- p.86 / Potential External Opportunities --- p.86 / Serve The End-user Customer Group --- p.86 / Increase sales in new markets or segments --- p.86 / Falling trade barriers in attractive foreign markets --- p.87 / Reducing barrier of entry to higher end market segment --- p.87 / Possible success of the new country-of-origin rules --- p.88 / Forward and backward vertical integration --- p.88 / Potential external threats --- p.89 / Rapid rise of lower-cost foreign competitors --- p.89 / Slower market growth of the low end segment --- p.89 / Possible adverse shifts in trade policies of foreign governments --- p.90 / Vulnerability to recession and business cycle --- p.90 / Strategic Cost Analysis and Competitive Strength Assessment --- p.90 / Strategic Issues Facing the Industry --- p.91 / Management of the unbalanced product portfolio --- p.91 / Penetration into new markets --- p.94 / Management of increasingly short product life cycle and quality awareness --- p.94 / Situation Analysis of the PRC's Timepieces industry --- p.95 / An Account of the PRC's Timepieces industry --- p.95 / History --- p.95 / Industry structure --- p.96 / Strategic industry for development --- p.96 / Increased awareness to product quality --- p.100 / Increased emphasis on market economy --- p.101 / Watches and clocks export --- p.102 / Increase Tie with Hong Kong --- p.103 / Evaluation of the present strategy --- p.103 / SWOT Analysis --- p.104 / Potential internal strengths . --- p.104 / Access to economies of scale --- p.104 / Shield from strong competition in domestic market --- p.104 / "Cost advantages in labor, land and raw materials " --- p.105 / Large domestic market --- p.105 / Strong determination to upgrade industry --- p.106 / Close to Hong Kong --- p.106 / Good relationship with the third world and the Eastern Europe . . --- p.107 / Potential internal weaknesses --- p.107 / Defective export policy --- p.107 / Lack of expertise and low technology levels --- p.107 / Low or no profitability --- p.108 / Weak in product design --- p.108 / Irrational pricing system --- p.109 / Outdated state legislation --- p.109 / A very narrow product line --- p.109 / "Weak in quality control, delivery and market image " --- p.110 / Weak in marketing --- p.110 / Potential external opportunities --- p.110 / Increase sales in all markets --- p.110 / Dominance in low end mechanical watch segment --- p.111 / Expand product line to meet broader range of customer needs --- p.111 / Potential external threats --- p.112 / Entry of lower-cost foreign competitors --- p.112 / Adverse shifts in foreign exchange rates --- p.112 / Retreat of foreign investors --- p.112 / Strategic Cost Analysis and Competitive Strength Assessment --- p.113 / Strategic Issues Facing the Industry --- p.114 / Upgrading the whole industry in all aspects --- p.114 / Management of Unbalanced Product Portfolio --- p.114 / STRATEGIC PLANNING FOR THE TIMEPIECES INDUSTRY OF HONG KONG AND THE PRC --- p.115 / Crafting Competitive Strategy for Hong Kong's Timepieces industry --- p.115 / Strategies to Attain Cost Advantages --- p.116 / Buying raw materials and movements from the PRC --- p.117 / Reducing expenses in inbound and outbound logistics --- p.118 / Shifting production to the PRC --- p.119 / Reducing marketing expenses --- p.119 / Reducing financial cost --- p.120 / Reducing administration cost --- p.120 / Strategies to Attain Differentiation Advantage --- p.121 / Improvement in Technical and Design Ability --- p.121 / Implementation of ISO 9000 quality assurance system --- p.122 / Improvement in customers' service --- p.123 / Other Strategies to Explore Opportunities and Reduce Threats --- p.124 / Joint development of the new markets with the PRC --- p.124 / Increasing sales to the PRC --- p.125 / Capture markets in Latin America and SE Asia --- p.126 / Crafting Competitive Strategy for the PRC --- p.126 / Strategic Alliance between Hong Kong and the PRC --- p.127 / CONCLUSIONS --- p.129 / Moves in Response to Changing Market Conditions --- p.132 / Approach to Vertical Integration --- p.132 / Moves to Secure a Competitive Advantage --- p.132 / Recent Moves to Strengthen Competitive Position --- p.133 / BIBLIOGRAPHY --- p.137

Su, Shuang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 100-106). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Objective --- p.2 / Chapter 1.3 --- Methodology --- p.3 / Chapter Chapter 2 --- Literature Survey --- p.5 / Chapter 2.1 --- The Escapement --- p.5 / Chapter 2.2 --- Signature Analysis of Mechanical Watches -- Traditional Methods and Existing Systems --- p.10 / Chapter 2.2.1 --- Estimating Rate Deviation --- p.10 / Chapter 2.2.2 --- Measuring Beat Error --- p.11 / Chapter 2.2.3 --- Error Detection with a Graphical Diagram --- p.12 / Chapter 2.2.4 --- Analyzing Watch Ticks --- p.13 / Chapter 2.3 --- Time-Frequency Distributions and Reassignment --- p.14 / Chapter 2.3.1 --- Time-Frequency Distributions --- p.14 / Chapter 2.3.2 --- Reassignment Method --- p.18 / Chapter 2.4 --- Finite Element Analysis --- p.19 / Chapter Chapter 3 --- Signature Analysis of Mechanical Watch Movement --- p.21 / Chapter 3.1 --- Time-Domain Analysis: Endpoint Detection --- p.21 / Chapter 3.2 --- Time-Domain Analysis: Error Detection with a Graphical Chart --- p.27 / Chapter 3.3 --- Analyzing Ticks: from Time-Domain Analysis to Time-Frequency Analysis --- p.31 / Chapter Chapter 4 --- Reassigned Time-Frequency Distributions --- p.34 / Chapter 4.1 --- Spectrogram --- p.34 / Chapter 4.2 --- Morlet Scalogram --- p.35 / Chapter 4.3 --- Smoothed Pseudo-Wigner-Ville Distribution --- p.36 / Chapter 4.4 --- Reassignment principle --- p.37 / Chapter 4.5 --- Reassigned Spectrogram (RSP) --- p.39 / Chapter 4.6 --- Reassigned Morlet Scalogram --- p.40 / Chapter 4.7 --- Reassigned SPWV --- p.40 / Chapter 4.8 --- Performance Evaluation of Time-frequency Distributions --- p.41 / Chapter Chapter 5 --- Modal analysis and simulation results --- p.47 / Chapter 5.1 --- FEA Eigensystems --- p.47 / Chapter 5.2 --- Modal Analysis in ANSYS --- p.48 / Chapter 5.3 --- Transient Dynamic Analysis of Watch Parts in ANSYS --- p.50 / Chapter Chapter 6 --- Fault Detection Examples --- p.60 / Chapter 6.1 --- Example I --- p.60 / Chapter 6.2 --- Example II --- p.64 / Chapter Chapter 7 --- System Development --- p.69 / Chapter Chapter 8 --- Conclusions --- p.74 / Appendix I --- p.77 / Chapter 1. --- GUI Layout of the CUHK-IPE Watch Signature Analyzer (WTimer.fig) : --- p.77 / Chapter 2. --- Main Function of CUHK-IPE Watch Signature Analyzer (WTimer.m): --- p.78 / Chapter 3. --- Other Functions Called by the Main Function: --- p.85 / Chapter 3.1 --- Function for Split Signal up into (Overlapping) Frames (enframe.m):…… --- p.86 / Chapter 3.2 --- Function for Detecting BPH of the Watch (bph´ؤdetection.m): --- p.86 / Chapter 3.3 --- Function for Calculation the Rate Deviation and Beat Error of the Watch (rate4_6.m): --- p.89 / Chapter 3.4 --- Function for Calculating the RSP of the Signal (tfrrsp.m): --- p.95 / Chapter 3.5 --- Window Generation Function (tftb_window.m): --- p.97 / References --- p.100

No description available.

Peroxyesters undergo homolytic O-O bond cleavage under thermal and photolytic conditions, forming an alkoxyl and acyloxyl radical, the latter of which rapidly decarboxylates to form a carbon centered radical. While peroxyesters are generally decomposed under anaerobic conditions to serve as sources of carbon-centered radicals to initiate radical reactions, it has been shown that β,γ-unsaturated peroxyesters can decompose to yield a delocalized carbon-centered radical which can serve as a precursor to a powerful peroxyl radical clock. This competitive kinetic approach is attractive as it allows the facile determination of rate constants for formal H-atom reactions between peroxyl radicals and reductants (e.g. phenolic and aromatic amine antioxidants) without the need for specialized equipment. Furthermore, this approach allows for the determination of this kinetic data in a wide variety of solvents. Herein, we present our work towards the development of a water-soluble peroxyl radical clock, such that the kinetics of reactions of peroxyl radicals with water-soluble reductants can be determined. To do so, we have designed β,γ-unsaturated peroxyesters analogous to those we have previously developed, but that bear either carboxylate or poly(ethylene glycol) moieties to improve solubility in aqueous media. In addition, we have carried out a preliminary investigation of the use of alkyl and acyl xanthates as precursors to peroxyl radical clocks. These radical precursors offer the advantage that they have a pronounced ultraviolet absorption that tails into the visible, permitting efficient photochemical generation of the same alkyl radicals, but at longer wavelengths than that which are currently employed. / Thesis (Master, Chemistry) -- Queen's University, 2010-05-31 09:53:50.676

Thesis (M.S.)--Ohio University, November, 1985. / Title from PDF t.p.

Inaug.--Diss.--Leipzig. / Lebenslauf.

No description available.

by Ho Chi-sing, Yeung Pud-Kuen. / Abstract also in Chinese / Bibliography: leaves 70-71 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1983