Structure and stability of an immunoglobulin superfamily domain from twitchin, a muscle protein of the nematode Caenorhabditis elegans

The NMR solution structure of an immunoglobulin superfamily module of twitchin (Ig 18') has been determined and the kinetic and equilibrium folding behaviour characterised. Thirty molecular coordinates were calculated using a hybrid distance geometry-simulated annealing protocol based on 1207 distance and 48 dihedral restraints. The atomic rms distributions about the mean coordinate for the ensemble of structures is 0.55( +/- 0.09) A for backbone atoms and 1.10( +/- 0.08) A for all heavy atoms. The protein has a topology very similar to that of telokin and the titin Ig domains and thus it falls into the I set of the immunoglobulin superfamily. The close agreement between the predicted and observed structures of Ig 18' demonstrates clearly that the I set profile can be applied in the structure prediction of immunoglobulin-like domains of diverse modular proteins. Folding studies reveal that the protein has relatively low thermodynamic stability, deltaG(H2O)U-F = 4.0 kcal mol(-1) at physiological pH. Unfolding studies suggest that the protein has considerable kinetic stability, the half life of the unfolding is greater than 40 minutes in the absence of denaturant.     

Scatter reduction with energy-weighted acquisition

The theory of energy-weighted acquisition (EWA) in nuclear medicine imaging is outlined, and a system that implements EWA is described. EWA reduces the effects of scattered radiation by allowing events of all energies to contribute to image formation, processing each energy with its own short-range spatial filter. This approach implements short-range energy-dependent filtering with an image buffer called a weighted acquisition module, providing scatter reduction with controllable noise and resolution properties. The system's response to point sources and planar distributions of radioactivity embedded in radiation-scattering media have been measured. EWA is compared to conventional energy-window acquisition, showing that the EWA approach provides improved image contrast     

Improvement of power supply EMC by chaos

The authors demonstrate the feasibility of using chaos to depress the spectral peaks of the interference from a switched mode power supply. A boost converter is used to show experimentally that the spectrum of the input current is spread, its peaks are reduced and EMC is improved, compared to the case when the circuit is operating periodically     

Subcontracting in commercial and residential construction: an empirical investigation

Some twenty years ago Robert Eccles argued for the theoretical existence of the quasifirm, a semi-integrated form of production in the construction industry, following a field study of home building firms in the USA. The study was aimed at substantiating some aspects of Williamson's transaction cost theory. The present work has similar intents, and illustrates the results of two recent field studies of homebuilders and commercial contractors, and the specific features of their subcontracting practice. Given the difficulty of an effective measurement of transaction costs in construction, Williamson's concept of atmosphere is suggested to explain the different approaches observed in subcontracting.     

The social organisation of communication in the home of the twenty-first century: an analysis of the future of paper-mail and implications for the design of electronic alternatives

This paper reports ongoing investigations into the use and role of paper-mail communications in domestic environments. It utilises ethnographically informed data to analyse how paper-mail supports various social roles within the home, particularly a division of labour whereby women tend to be largely responsible for what may be called "managing the home". Implications for the future of paper-mail are considered, as well as suggestions made about how email tools may be designed to reflect the patterns of social organisation within the home. Electronic Publication     

Reinforced Stone Columns in Weak Deposits: Laboratory Model Study

This paper investigates the performance of stone columns in a weak deposit such as peat. It evaluates the effects of reinforcing stone columns by jacketing with a tubular wire mesh and bridging reinforcement with a metal rod and a concrete plug. A series of plate loading tests was conducted on isolated stone columns installed in a soil bed consisting of a peat layer sandwiched between two layers of sand. The load–displacement characteristics of footings supported by stone columns were investigated by applying load to a circular plate supported on: (a) untreated soil; (b) soil treated with stone columns; and (c) soil treated with stone columns reinforced with the above reinforcing techniques. The work has shown that the settlement characteristics of the soil can be improved by installing stone columns and that a significant enhancement in the load–settlement response is achieved when the columns are reinforced by the various methods.     

The introduction of new technology into the household

Economic considerations should be fundamental to the design process. Modern economics provides a useful tool to analyse consumer demand for new technology. This paper sets out some basic economic concepts and then looks at the history of the introduction into the household of phones. TVs and VCRs, CDs and home computers and the Internet. It then takes the first tentative steps towards identifying the explanatory variables that should be included in a model of demand for new domestic technology.     

Family ties in tough times: How young adults and their parents view the U.S. economic crisis.

The present intergenerational study examined the perceived impact of the recent U.S. economic crisis on a sample of 68 young adult–parent dyads. The relative contribution of perceived economic pressure, reports of adult child–parent relationship quality, and concerns about the economic future in accounting for variation in self-reports of psychological distress for adult children and their middle-aged parents were examined. Parents' concerns about their children's economic future accounted for variation in their reports of anxiety and depressed mood above and beyond that of perceived economic pressures and their views of the parent–child relationship. In contrast, for young adults, reports of personal economic pressure were generally related to self-reported anxiety and depressed mood. Implications of findings for research and practice are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Purification of a WD repeat protein, EMAP, that promotes microtubule dynamics through an inhibition of rescue

The major microtubule-associated protein in echinoderms is a 77-kDa, WD repeat protein, called EMAP. EMAP-related proteins have been identified in sea urchins, starfish, sanddollars, and humans. We describe the purification of sea urchin EMAP and demonstrate that EMAP binding to microtubules is saturable at a molar ratio of 1 mol of EMAP to 3 mol of tubulin dimer. Unlike MAP-2, MAP-4, or tau proteins, EMAP binding to microtubules is not lost by cleavage of tubulin with subtilisin. In addition to binding to the microtubule polymer, EMAP binds to tubulin dimers in a 1:1 molar ratio. The abundance of EMAP in the egg suggests that it could function to regulate microtubule assembly. To test this hypothesis, we examined the effects of EMAP on the dynamic instability of microtubules nucleated from axoneme fragments as monitored by video-enhanced differential interference contrast microscopy. Addition of 2.2 microM EMAP to 21 microM tubulin results in a slight increase in the elongation and shortening velocities at the microtubule plus ends but not at the minus ends. Significantly, EMAP inhibits the frequency of rescue 8-fold without producing a change in the frequency of catastrophe. These results indicate that EMAP, unlike brain microtubule-associated proteins, promotes microtubule dynamics.     

Effects of temperature and humidity on the growth and optical properties of sulphuric acid—water droplets in the stratosphere

Theoretical calculations of the optical properties of equilibrium size sulphuric acid-water solution droplets under stratospheric conditions are presented. We evaluate the changes in the physical properties of the aerosol particles which accompany fluctuations in environmental temperature and humidity, and present them in tabular and graphical form. These results are used in conjunction with Mie scattering theory to show how the aerosol backscatter at 0.6943 μm wavelength and the aerosol extinction at 1.0 μm wavelength are affected by variations in the stratospheric temperature and humidity.