Functional analysis of melanocortin 2 receptor variants and dimer formation

PhDThe adrenocorticotropic hormone (ACTH) receptor, also known as the melanocortin 2 receptor (MC2R) is primarily expressed in the adrenal gland and binds to ACTH to activate a signalling cascade that leads to steroidogenesis. The characterisation of the melanocortin 2 receptor has previously been hindered by the failure of cell surface expression in heterologous cells. Unlike other melanocortin receptors, MC2R surface expression requires an accessory protein called melanocortin 2 receptor accessory protein (MRAP). MRAP has been shown to facilitate trafficking of MC2R from the endoplasmic reticulum to the plasma membrane and it also has a role in MC2R signalling. Naturally occurring MC2R mutations occur in Familial Glucocorticoid Deficiency (FGD) type 1. The functional defect remains uncertain for the majority, mainly due to the difficulties in characterisation which has been limited in Y6 cells (mouse derived adrenal cells which are free of MCRs) because of poor transfection efficiency. The first two results chapter of this thesis focus on the molecular biology of FGD mutations and the genotype-phenotype relationship of the disease. The functional defects of these mutations have been analysed in transfectable heterologuous cells stably expressing MRAP. The majority of the missense mutations are trafficking-defective, and yet all appear to interact with MRAP, but some mutations are trafficking-competent and fail to signal. Clinical details including the age of presentation; presenting plasma ACTH and cortisol; height and weight were examined in FGD type 1 and 2 (mutation of MC2R or MRAP respectively) to determine whether there is a genotype-phenotype correlation. Within FGD type 1, there was no clear clinical distinction between the functional defects in vitro and in vivo data. However, there were phenotypic differences between 3 FGD type 1 and 2, with FGD 2 appearing to be more severe with a younger age and a lower height SDS at presentation. The final part of this thesis focuses on MC2R dimerisation and signalling of the receptor. Co-immunoprecipitation studies showed that MC2R homodimerisation is constitutive. This interaction was not enhanced in the presence of MRAP or ACTH. No effect on signalling was observed. When a signalling mutant (R128C) and a ligand binding mutant (D103N) were co-transfected with MRAP and stimulated with ACTH, signalling was not restored, suggesting no cross talk between the two receptors. In the final discussion the implication of these findings are considered with respect to their relevance to disease and novel therapeutic strategies

Design Of Multiply-By-Two Amplifier For 1.5 Bit Pipelined Analogue-To-Digital Converter Application

This report explain about the design of multiply-by-two amplifier for Analogue-To-Digital Converter. The specification of the operational amplifier is 40dB of gain, and 1MHz cut-off frequency. Silterra 0.13um process technology is used in this work. The amplifier topology used in this research is Folded cascode which gives larger output swing. Differential pairs Common-mode feedback is used to overcome the mismatch of source current and to fix the folded cascode output voltage level at 350mV. The proposed design was able to achieve DC gain of 44.77dB and 1.06MHz cut-off frequency. The designed amplifier power consumption is very low, which is 9.598mW. Figure of merit of this design ar

Looking again at Taiwan's Lü Hsiu-lien: A female vice president or a feminist vice president?

In 2000, Lü Hsiu-lien was elected Taiwan's first female vice president, adding to the striking successes of Asian women in electoral politics. Lü differs from the majority of Asia's "ruling women" in two key respects: she was elected without reliance on "dynastic descent" and she has a long track record as a feminist activist. Her position as both a pioneering feminist and a female vice president prompts us to ask whether she was able to promote a pro-woman agenda during her tenure as vice president. We conclude that despite constraints on Lü's pursuit of an overt feminist agenda-including the patriarchal political culture and a gap between Lü and Taiwan's contemporary feminist movement-she is significant as a female leader who transcends both the Asian dynastic model and the tokenistic model of women as "flower vases," while also contributing vitally to the development of an indigenous Taiwanese feminist theory

Hydrodynamic forces on a horizontal cylinder under waves and current

By assuming the linear superposition principle to be valid, the hydrodynamic forces on a horizontal cylinder under waves and current are examined. In this study, towing a cylinder in waves is used to simulate a cylinder under waves and current. The experimental technique is proved valid through theoretical considerations and experimental investigations. For large current velocity (or high tow speed), the drag coefficient for waves and current approaches that for steady flow. If the current is large enough, these two values are nearly identical. In addition, the behavior of force coefficients for a horizontal cylinder in waves only with moderately large Reynolds number, Keulegan-Carpenter number and frequency parameter is examined. The results show that the forces on a horizontal cylinder in waves are smaller than those for planar oscillatory flow. Whether the total acceleration or local acceleration should be used in the inertia term is a debatable point for using the Morison equation. To study this problem, the similarities and differences between these two accelerations for different water depths and wave heights are examined. The results show there is no evident difference in force prediction if the related force coefficients are used. To check the suitability of this data for determining Cd and/or Cm, an indicator, RR, is developed for the horizontal smooth cylinder in waves and current

Insights on the Formation and Fate of Organic Nitrates in the Atmosphere from Field and Laboratory Observations

Alkenes are oxidized rapidly in the atmosphere by addition of OH and subsequently O2, leading to the formation of peroxy radicals. These peroxy radicals react with NO to form organic nitrates through a minor radical-terminating branching pathway. Over large regions of the continental boundary layer, the formation of organic nitrates control tropospheric ozone and the lifetime of NOx. Laboratory investigations described herein show that the yield of nitrates through this pathway is larger than previously described for alkenes, and the yield increases with the number of heavy atoms. This result is used to interpret field observations taken over Houston in the summer of 2013. These measurements show that small alkenes still play a large role in ozone production more than a decade after they had been identified as a causal factor. In further studies, measurements of isoprene hydroxy nitrates (ISOPN) and hydroperoxides, formed from the OH oxidation of isoprene, are used to diagnose the complexities of reversible O2 addition for allylic hydroxy isoprene radicals. It is shown that over most of the atmosphere, isoprene's peroxy radical isomers are in their equilibrium distribution. In this regime, hydroxy peroxy radical isomers comprise approximately 95% of the radical pool, a much higher fraction than in the nascent (kinetic) distribution. Intramolecular H-shift isomerization from the Z hydroxy peroxy radical isomers produced from OH addition to C4 is estimated to be 4s-1 at 297K. While the Z isomer is initially produced in low yield, it is continually reformed via decomposition of the hydroxy peroxy radicals. As a result, unimolecular chemistry from this isomer contributes as much as half of the atmospheric fate of the entire pool of peroxy radicals formed via addition of OH at C4. In contrast, unimolecular chemistry following OH addition at C1 is slower and less important. Field observations of alkyl nitrates over the Southeastern United States during the summer over forested environments show that there are still gaps in our understanding of the organic nitrate budget. The formation of isoprene hydroxy nitrates (ISOPN) is shown to be a dominant NOx loss pathway during the day

Functional consequence of a novel Y129C mutation in a patient with two contradictory melanocortin-2-receptor mutations

L F C and T-T C are supported by M R C Clinical Research Training Fellowships (grant numbers G0600408, G0700581) and L A M by the Wellcome Trust (grant number 076430/Z/05/7)

Collaborating on ESG consulting, reporting, and communicating education: Using partner maps for capability building design

Given the rising demand for environmental, social, and governance (ESG) talents, this study aims to provide a multidisciplinary outlook of specific capability requirements for ESG talents, focusing on the use of ESG and carbon information, thereby providing a roadmap for ESG education. Following design science framework conventions and running design workshops that integrate design thinking of “how might we” design questions, literature analysis, and expert interviews across disciplines, this study presents findings regarding three main activities—consulting, reporting, and communicating. Based on the iterations of design workshops that adopt a circular economy-based partner map design canvas for stakeholder analysis with procedures such as expert interviews and literature analysis, three partner/capability maps were generated to map stakeholders and explore the capabilities needed. ESG and carbon information digital and data skills emerged as the core capability to complete all the three tasks. A conceptual framework—a Smart System of ESG and Carbon Information—is proposed to summarize planning, operating, and communicating with ESG and carbon information, along with high-level organizational actions and talent capabilities. It identifies the building blocks of an ESG operating system within an enterprise to engage various stakeholders for value-creation collaboration. Despite the limitation of a lack of comprehensive review and limited geographic and disciplinary representation, this study provides a roadmap for enterprises and universities to explore and define talent requirements and create specific education and training programs