Polarization-dependent detection of impulsive stimulated Raman scattering in α-quartz

The stimulation and detection of both the A- and E-symmetry Raman lines in α-quartz using ultrafast impulsive stimulated Raman scattering is presented. Using a flexible experimental set-up, each nuclear oscillatory mode is selected and analysed in the time domain separately. The mode selection is made possible with optical summing of the fields involved to reduce noise and assure accurate synchronization. The experimental procedure is compared to optical heterodyne detection Raman-induced Kerr effect spectroscopy (OHD-RIKES) and the data is compared with standard frequency-domain measurements.     

Charley: a linguistic formalism applied to writing environment design

Abstract

A context-sensitive grammar of English is being developed into an object-oriented programming language, which will in turn be used to implement the goal of the Pharos project: an interactive writing environment for designing social research questionnaires. The paper consists of a series of questions and answers in three sections: introduction to the grammar, its relevance to writers and its relevance to the Pharos project.     

Processing of ceramic-metal interpenetrating composites

Interpenetrating composites consist of three-dimensionally interpenetrating matrices of two different phases; in the present work they were alumina and aluminium–magnesium alloys and were produced by infiltrating ceramic foams with molten alloys. The foams were made by mechanically agitating ceramic suspensions to entrain gases and then setting the structure via the in-situ polymerisation of organic monomers, a process known as gel casting. This resulted in the foams having a very open and interconnected structure that could be easily infiltrated by the molten metals. Previous composites have been produced at Loughborough University using squeeze casting; however, whilst infiltration was usually accomplished in a matter of seconds, the resulting size and shape of the composite was limited. Hence the present work has focused on investigating the potential for using gravity-fed infiltration. Whilst this was much slower, often taking several minutes, when optimised it is believed it will offer the potential for the production of large and complex-shaped pieces.The composites were produced at atmospheric pressure by infiltrating 2–10 wt.% magnesium content Al–Mg alloys into 20% dense Al₂O₃ foams with highly interconnected porosity. The processing parameters of temperature, ≥900 °C, and atmosphere, flowing N₂–Ar, were investigated to determine the processing window and infiltration kinetics. In-situ observation of the process shows that infiltration is faster at higher temperatures, Mg contents and N₂ partial pressures. Both optical and scanning electron microscopy (SEM) have been used to characterise the composites.     

Residential bioenergy heating: A study of consumer perceptions of improved woodstoves

Consumers’ choices play a key role for the development of biomass heating in the residential sector. The city of Oslo has granted subsidies to households who change to new, improved low-emission woodstoves. The purpose of this study is to expand the knowledge about users’ experiences and attitudes to residential biomass heating. An adapted model of the Theory of Planned Behavior was used to model households’ inclination to continue using their woodstoves for heating. More than 800 questionnaires were collected from households that recently had invested in an improved woodstove. The respondents were satisfied with the new woodstoves. The respondents also considered themselves competent to use and maintain the stove and few had problems acquiring fuelwood. Further analyses showed that the intention to continue to use the new woodstove depends on economic benefits, heating performance, perceived time and effort to operate the stove, environmental effects of heating as well as perceived subjective norm. The results imply that when marketing a modern technology for bioenergy heating, both public authorities and producers should consider issues related to the users’ perception of subjective norm, such as perceived status of using bioenergy or environmental concerns, when designing campaigns to promote the use of woodstoves.     

An interferometric platform for studying AFM probe deflection

This paper describes an interferometric platform for measuring the full-field deflection of atomic force microscope (AFM) probes and generic cantilevers during quasi-static loading. The platform consists of a scanning white light interferometer (SWLI), holders for the cantilevers, a translation stage, a rotation (tip-tilt) stage, and an adapter plate to connect these items to the SWLI table. Visualization of cantilever bending behavior is demonstrated for snap-in against a rigid surface, cantilever-on-cantilever tests, and a damaged AFM probe. A new approach to normal force calculation using a polynomial fit to the cantilever deflection profile is also presented and verified experimentally. The method requires only the coefficient for the third order (cubic) term from the fit to the deflection profile, the elastic modulus, and the area moment of inertia for the cantilever under test.     

Biosynthesis and spectroscopic characterization of 2-TM fragments encompassing the sequence of a human GPCR, the Y4 receptor

This paper presents a divide‐and‐conquer approach towards obtaining solution structures of G protein‐coupled receptors. The human Y4 receptor was dissected into two to three transmembrane helix fragments, which were individually studied by solution NMR. We systematically compared various biosynthetic routes for the expression of the fragments in Escherichia coli and discuss purification strategies. In particular, we have compared the production of transmembrane (TM) fragments as inclusion bodies by using the ΔTrp leader sequence, with membrane‐directed expression by using Mistic as the fusion partner, and developed methods for enzymatic cleavage. In addition, direct expression of two‐TM fragments into inclusion bodies is a successful route in some cases. With the exception of TM13, we could produce all fragments in isotope‐labeled form in quantities sufficient for NMR studies. Almost complete backbone resonance assignment was obtained for the first two helices, as well as for helices 5 and 7, and a high degree was obtained for TM6, while conformational exchange processes resulted in the disappearance of many signals from TM4. In addition, complete assignments were obtained for all residues of the N‐terminal domain, as well as the extracellular and cytosolic loops (with the exception of an undecapeptide segment in the second extracellular loop, EC2) and for the complete cytosolic C‐terminal tail. In total, backbone resonances of 78 % of all residues were assigned for the Y4 receptor. Predictions of secondary structure based on backbone chemical shifts indicate that most residues from the TM regions adopt helical conformations, with exception of those around polar residues or prolines. However, the domain boundaries differ slightly from those predicted for homology models. We suggest that the obtained chemical shifts might be useful in assigning the full‐length receptor.     

Characterization of C-alkyl amidines as bioavailable covalent reversible inhibitors of human DDAH-1

C‐Alkyl amidine analogues of asymmetric N^ω,N^ω‐dimethyl‐L ‐arginine are dual‐targeted inhibitors of both human DDAH‐1 and nitric oxide (NO) synthase, and provide a promising scaffold for the development of therapeutics to control NO overproduction in a variety of pathologies including septic shock and some cancers. Using a two‐part click‐chemistry‐mediated activity probe, a homologated series of C‐alkyl amidines were ranked for their ability to inhibit DDAH‐1 within cultured HEK 293T cells. N⁵‐(1‐Iminopentyl)‐L ‐ornithine was determined to be the most potent compound in vitro (K_d=7 μM ) as well as in cultured cells, and the binding conformation and covalent reversible mode of inhibition was investigated by comparison of interactions made with DDAH‐1 and a catalytically inactive C274S variant, as gauged by X‐ray crystallography and isothermal titration calorimetry. By interrupting the ability of the inhibitor to form a covalent bond, the contribution of this interaction could be estimated. These results suggest that further stabilization of the covalent adduct is a promising strategy for lead optimization in the design of effective reagents to block NO synthesis.     

Attachment deficits, personality structure, and PTSD.

Comments on an article by P. Verhaeghe and S. Vanheule (see record 2006-00627-003). The question surrounding etiological factors informing the emergence of posttraumatic stress disorder (PTSD) due to preexisting personality deficits is explored in relation to recent advances in understanding the indissolubility between attachment pathology and developmental trauma. Universal generalizations regarding the causal relation between structural self-deficits and the emergence of PTSD remain suspended. The nature of traumatic representation continues to be a contested area of empirical and theoretical debate, the consequences of which may inevitably inform clinical technique. (PsycINFO Database Record (c) 2010 APA, all rights reserved)