Controlling the crystal polymorph by exploiting the time dependence of nucleation rates

Most substances can crystallise into two or more different crystal lattices, called polymorphs. Despite this, there are no systems in which we can quantitatively predict the probability of one competing polymorph forming, instead of the other. We address this problem using large scale (hundreds of events) studies of the competing nucleation of the alpha and gamma polymorphs of glycine. In situ Raman spectroscopy is used to identify the polymorph of each crystal. We find that the nucleation kinetics of the two polymorphs is very different. Nucleation of the alpha polymorph starts off slowly but accelerates, while nucleation of the gamma polymorph starts off fast but then slows. We exploit this difference to increase the purity with which we obtain the gamma polymorph by a factor of ten. The statistics of the nucleation of crystals is analogous to that of human mortality, and using a result from medical statistics we show that conventional nucleation data can say nothing about what, if any, are the correlations between competing nucleation processes. Thus we can show that, with data of our form, it is impossible to disentangle the competing nucleation processes. We also find that the growth rate and the shape of a crystal depends on when it nucleated. This is new evidence that nucleation and growth are linked.Comment: 8 pages, plus 17 pages of supplementary materia

A New Method for Assessing the Resiliency of Large, Complex Networks

Designing resilient and reliable networks is a principle concern of planners and private firms. Traffic congestion whether recurring or as the result of some aperiodic event is extremely costly. This paper describes an alternative process and a model for analyzing the resiliency of networks that address some of the shortcomings of more traditional approaches – e.g., the four-step modeling process used in transportation planning. It should be noted that the authors do not view this as a replacement to current approaches but rather as a complementary tool designed to augment analysis capabilities. The process that is described in this paper for analyzing the resiliency of a network involves at least three steps: 1. assessment or identification of important nodes and links according to different criteria 2. verification of critical nodes and links based on failure simulations and 3. consequence. Raster analysis, graph-theory principles and GIS are used to develop a model for carrying out each of these steps. The methods are demonstrated using two, large interdependent networks for a metropolitan area in the United States.

GAIT TRAINING WITH AUDITORY RHYTHMS AND INSTRUCTIONS IN CHRONIC STROKE

During walking in healthy adults, characteristic movement patterns between the upper and lower body relate directly to walking velocity. In persons who suffer a stroke, walking velocity decreases as motor deficits appear in both the arm and leg opposite the side of the stroke. Recent findings indicate that treadmill walking to a metronome beat impacts arm motion, however, the effect is dependent on the severity of motor deficits. The changes in arm motion lead to changes that are indicative of improvements in overall walking function. The purpose of this project is to determine the efficacy of over-ground gait training using an external auditory rhythm directed at arm movement versus leg movement on improving movement coordination, walking velocity, and daily physical activity in persons who have suffered a stroke

Managing Access to Biobanks:How Can We Reconcile Privacy and Public Interests in Genetic Research?

This article is concerned with the ultimate objectives of genetic biobanks set up to promote the public interest—being the sharing of samples and data for medical research—and the consequences for personal privacy of realising them. Our aim is to chart the values, interests and principles in play, to consider the challenges of realizing biobanking objectives on a global scale, and to propose viable ways forward that ensure, as far as possible, that access provisions remain fit for purpose throughout the entire life of a biobank, while adequately protecting the privacy interests at stake. It is argued that key features in any robust access model must include mechanisms to (a) maintain participant trust in management of the resource and to measure and respond to participants’ expectations, (b) facilitate and promote the sharing of benefits, and (c) respond timeously and effectively to new challenges

The Impact of Halo Properties, Energy Feedback and Projection Effects on the Mass-SZ Flux Relation

We present a detailed analysis of the intrinsic scatter in the integrated SZ effect - cluster mass (Y-M) relation, using semi-analytic and simulated cluster samples. Specifically, we investigate the impact on the Y-M relation of energy feedback, variations in the host halo concentration and substructure populations, and projection effects due to unresolved clusters along the line of sight (the SZ background). Furthermore, we investigate at what radius (or overdensity) one should measure the integrated SZE and define cluster mass so as to achieve the tightest possible scaling. We find that the measure of Y with the least scatter is always obtained within a smaller radius than that at which the mass is defined; e.g. for M_{200} (M_{500}) the scatter is least for Y_{500} (Y_{1100}). The inclusion of energy feedback in the gas model significantly increases the intrinsic scatter in the Y-M relation due to larger variations in the gas mass fraction compared to models without feedback. We also find that variations in halo concentration for clusters of a given mass may partly explain why the integrated SZE provides a better mass proxy than the central decrement. Substructure is found to account for approximately 20% of the observed scatter in the Y-M relation. Above M_{200} = 2x10^{14} h^{-1} msun, the SZ background does not significantly effect cluster mass measurements; below this mass, variations in the background signal reduce the optimal angular radius within which one should measure Y to achieve the tightest scaling with M_{200}.Comment: 12 pages, 6 figures, to be submitted to Ap

The experiences of spirituality among adults with mental health difficulties: a qualitative systematic review

Aims Despite an increasing awareness of the importance of spirituality in mental health contexts, a ‘religiosity gap’ exists in the difference in value placed on spirituality and religion by professionals compared with service users. This may be due to a lack of understanding about the complex ways people connect with spirituality within contemporary society and mental health contexts, and can result in people’s spiritual needs being neglected, dismissed or pathologised within clinical practice. The aim of this qualitative systematic review is to characterise the experiences of spirituality among adults with mental health difficulties in published qualitative research. Methods An electronic search of seven databases was conducted along with forward and backward citation searching, expert consultation and hand-searching of journals. 38 studies were included from 4944 reviewed papers. The review protocol was pre-registered (PROSPERO:CRD42017080566). Results A thematic synthesis identified six key themes: Meaning-making (sub-themes: Multiple explanations; Developmental journey; Destiny versus autonomy), Identity, Service-provision, Talk about it, Interaction with symptoms (sub-themes: Interactive meaning-making; Spiritual disruption) and Coping (sub-themes: Spiritual practices; Spiritual relationship; Spiritual struggles; Preventing suicide), giving the acronym MISTIC. Conclusions This qualitative systematic review provides evidence of the significant role spirituality plays in the lives of many people who experience mental health difficulties. It indicates the importance of mental health professionals being aware of and prepared to support the spiritual dimension of people using services. The production of a theory-based framework can inform efforts by health-providers to understand and address people’s spiritual needs as part of an integrated holistic approach towards care

New approaches in the management of multiple sclerosis

Multiple sclerosis (MS) is a central nervous system chronic inflammatory disease that is characterized by an extensive and complex immune response. Scientific advances have occurred in immunology, pathophysiology, and diagnostic and clinical assessment tools, and recent discovery of unique therapeutic targets has spurred numerous Phase II and Phase III clinical trials. Reductions in MS relapse rates and improvements in T2 or gadolinium-enhancing lesion burdens have been reported from Phase III trials that include fingolimod, alemtuzumab, cladribine, and rituximab. Promising Phase II trial data exist for teriflunomide, daclizumab, laquinimod, and fumarate. The optimism created by these favorable findings must be tempered with evaluation of the adverse effect profile produced by these new agents. Given the discovery of progressive multifocal leukoencephalopathy with the use of natalizumab, ongoing vigilance for rare and life-threatening reactions due to new agents should be paramount. Patients with MS often experience difficulty with ambulation, spasticity, and cognition. Recent clinical trial data from two Phase III dalfampridine-SR trials indicate certain patients receive benefits in ambulation. This article provides an overview of data from clinical trials of newer agents of potential benefit in MS