Synthesis of [2,3]-fused indoles via vinyl azides

Imperial Users onl

Dual-spin attitude control for outer planet missions

The applicability of dual-spin technology to a Jupiter orbiter with probe mission was investigated. Basic mission and system level attitude control requirements were established and preliminary mechanization and control concepts developed. A comprehensive 18-degree-of-freedom digital simulation was utilized extensively to establish control laws, study dynamic interactions, and determined key sensitivities. Fundamental system/subsystem constraints were identified, and the applicability of dual-spin technology to a Jupiter orbiter with probe mission was validated

High voltage solar array study Final report

High voltage solar array stud

Spatial intensity distribution analysis quantifies the extent and regulation of homodimerization of the secretin receptor

Previous studies have indicated that the G protein-coupled secretin receptor is present as a homo-dimer, organized through symmetrical contacts in transmembrane domain IV, and that receptor dimerization is critical for high potency signalling by secretin. However, whether all of the receptor exists in the dimeric form or if this is regulated, is unclear. We used measures of quantal brightness of the secretin receptor tagged with monomeric enhanced green fluorescent protein (mEGFP) and Spatial Intensity Distribution Analysis to assess this. Calibration using cells expressing plasma membrane-anchored forms of mEGFP initially allowed demonstration that the Epidermal Growth Factor receptor is predominantly monomeric in the absence of ligand and whilst wild type receptor was rapidly converted to a dimeric form by ligand, a mutated form of this receptor remained monomeric. Equivalent studies showed that at moderate expression levels the secretin receptor exists as a mixture of monomeric and dimeric forms, with little evidence of higher-order complexity. However, sodium butyrate induced up-regulation of the receptor resulted in a shift from monomeric towards oligomeric organization. By contrast, a form of the secretin receptor containing a pair of mutations on the lipid-facing side of transmembrane domain IV was almost entirely monomeric. Down-regulation of the secretin receptor-interacting G protein Gαs did not alter receptor organization, indicating that dimerization is defined specifically by direct protein-protein interactions between copies of the receptor polypeptide, whilst short term treatment with secretin had no effect on organization of the wild type receptor but increased the dimeric proportion of the mutated receptor variant

Future impacts of fresh water resource management: sensitivity of coastal deltas

We present an assessment of contemporary and future effective sealevel rise (ESLR) using a sample of 40 deltas distributed worldwide. For any delta, ESLR is a net rate defined by eustatic sea-level rise, natural gross rates of fluvial sediment deposition and subsidence, and accelerated subsidence due to groundwater and hydrocarbon extraction. Present-day ESLR, estimated from geospatial data and a simple model of deltaic dynamics, ranges from 0.5 to 12.5 mm year-1. Reduced accretion of fluvial sediment from upstream siltation of reservoirs and freshwater consumptive irrigation losses are primary determinants of ESLR in nearly 70% of the deltas, while for only 12% eustatic sea-level rise predominates. Future scenarios indicate a much larger impact on deltas than previously estimated. Serious challenges to human occupancy of deltas worldwide are conveyed by upland watershed factors, which have been studied less comprehensively than the climate change and sea-level rise question