Molecular dynamics simulations of aqueous urea solutions: Study of dimer stability and solution structure, and calculation of the total nitrogen radial distribution function GN(r

Molecular dynamics simulations have been performed in order to study the structure of two molal urea solutions in D2O. Several initial dimer configurations were considered for an adequate sampling of phase space. Eventually all of them appeared to be unstable, when system size and periodic boundary conditions are chosen properly, even after a very careful equilibration. The total nitrogen scattering function GN(r), calculated from these simulations, is in good agreement with neutron scattering experiments when both intra- and intermolecular correlations are considered and the experimental truncation ripples are introduced by a Fourier transform of GN(r) back and forth. The simple pair potential model that we used gives results in good agreement with experiments and with a much more involved potential model, recently described in the literature [J. Chem. Phys. 95, 8419 (1991)]

From wave function to crystal morphology: application to urea and alpha-glycine

In this paper the relation between the molecular electron density distribution and the crystal growth morphology is investigated. Accurate charge densities derived from ab initio quantum chemical calculations were partitioned into multipole moments, to calculate the electrostatic contribution to the intermolecular interaction energy. For urea and alpha-glycine the F-faces or connected nets were determined according to the Hartman-Perdok PBC theory. From attachment energy and critical Ising temperature calculations, theoretical growth forms were constructed using different atom-atom potential models. These were compared to the Donnay-Harker model, equilibrium form and experimental growth forms. In the case of alpha-glycine, the theoretical growth forms are in good agreement with crystals grown from aqueous solution. Crystals obtained by sublimation seem to show some faces which are not F-faces sensu stricto

Constitutive modeling of metastable austenitic stainless steel

A stress-update algorithm is developed for austenitic metastable steels which undergo phase evolution during deformation. The material initially comprises only the soft and ductile austenite phase which due to the phenomenon of mechanically induced martensitic transformation, transforms completely to the hard and brittle martensite. A mean-field homogenization algorithm is developed that can predict the mechanical response of the composite material during transformation. Furthermore, a physically based transformation model is developed that predicts the amount of transformation during deformation

Influence of stress state and strain path on deformation induced martensitic transformations

The mechanically induced transformation behavior of 12Crsingle bond9Nisingle bond 4Mo (ASTM A 564) austenitic stainless steel is investigated in different stress states. This phenomenon is studied experimentally on a plane-stress biaxial test facility. The facility can load a sheet specimen simultaneously in shear and tension which enables us to investigate the effect of stress state on transformation kinetics. The martensite fraction is monitored via a magnetic sensor while the strain is measured using a camera and a dot-tracking software

A stress integration algorithm for phase transforming steels

A new stress integration algorithm for the constitutive models of materials that\ud undergo strain-induced phase transformation is presented. The most common materials that\ud fall into this category are metastable austenitic stainless (TRIP) steels. These materials can\ud be classi¯ed as metal-matrix composites which comprise a soft and a hard metallic phase. A\ud homogenization algorithm is presented that can estimate the evolution of state variables in each\ud phase for a given strain increment. The elastic-plastic behavior of the phases are calculated\ud individually using large deformation theory and the calculated algorithmic tangent moduli are\ud used in different homogenization schemes. Furthermore, the phase transformation process in\ud austenitic stainless steels involves a volumetric expansion and an inelastic shape change collinear\ud with the deviatoric stress. This transformation plasticity is approximated by a phenomenological\ud model and incorporated in the stress update algorithm

Internal consistency reliability and construct validity of the Attitude toward Muslim Proximity Index (AMPI): a measure of social distance

The Attitude toward Muslim Proximity Index (AMPI) is a six-item scale that uses tolerance to different degrees of social distance to assess prejudice towards Muslims. It was tested on 1777 teenage school children from northern England who indicated their religion as either 'Christian' or 'no religion', and demonstrated good internal reliability (Cronbach's alpha = .81). The index was higher among pupils who supported the views of the British National Party and among those who believed that British Muslims should adopt Western culture; but lower among those who knew Muslims or had Muslim friends. The AMPI is a useful measure of Islamophobic attitudes that does not rely on responses to specific events or on detailed knowledge of the Muslim religion

Factors relating to the uptake of interventions for smoking cessation amongst pregnant women: a systematic review and qualitative synthesis

Introduction The review had the aim of investigating factors enabling or discouraging the uptake of smoking cessation services by pregnant women smokers. Methods The literature was searched for papers relating to the delivery of services to pregnant or recently pregnant women who smoke. No restrictions were placed on study design. A qualitative synthesis strategy was adopted to analyse the included papers. Results Analysis and synthesis of the 23 included papers suggested ten aspects of service delivery that may have an influence on the uptake of interventions. These were: whether or not the subject of smoking is broached by a health professional; the content of advice and information provided; the manner of communication; having service protocols; follow-up discussion; staff confidence in their skills; the impact of time and resource constraints; staff perceptions of ineffectiveness; differences between professionals; and obstacles to accessing interventions. Discussion The findings suggest variation in practice between services and different professional groups, in particular regarding the recommendation of quitting smoking versus cutting down, but also in regard to procedural aspects such as recording status and repeat advice giving. These differences offer the potential for a pregnant woman to receive contradicting advice. The review suggests a need for greater training in this area and the greater use of protocols, with evidence of a perception of ineffectiveness/pessimism towards intervention amongst some service providers

Unlocking the potential of anti-CD33 therapy in adult and childhood acute myeloid leukaemia

Acute Myeloid Leukaemia (AML) develops when there is a block in differentiation and uncontrolled proliferation of myeloid precursors, resulting in bone marrow failure. AML is a heterogeneous disease clinically, morphologically, and genetically, and biological differences between adult and childhood AML have been identified. AML comprises 15-20% of all children less than fifteen years diagnosed with acute leukaemia. Relapse occurs in up to 40% of children with AML and is the commonest cause of death.1,2 Relapse arises from leukaemic stem cells (LSCs) that persist after conventional chemotherapy. The treatment of AML is challenging and new strategies to target LSCs are required. The cell surface marker CD33 has been identified as a therapeutic target, and novel anti-CD33 immunotherapies are promising new agents in the treatment of AML. This review will summarise recent developments emphasising the genetic differences in adult and childhood AML, while highlighting the rationale for CD33 as a target for therapy, in all age groups