Temporal SNR characteristics in segmented 3D-EPI at 7T.

Three-dimensional segmented echo planar imaging (3D-EPI) is a promising approach for high-resolution functional magnetic resonance imaging, as it provides an increased signal-to-noise ratio (SNR) at similar temporal resolution to traditional multislice 2D-EPI readouts. Recently, the 3D-EPI technique has become more frequently used and it is important to better understand its implications for fMRI. In this study, the temporal SNR characteristics of 3D-EPI with varying numbers of segments are studied. It is shown that, in humans, the temporal variance increases with the number of segments used to form the EPI acquisition and that for segmented acquisitions, the maximum available temporal SNR is reduced compared to single shot acquisitions. This reduction with increased segmentation is not found in phantom data and thus likely due to physiological processes. When operating in the thermal noise dominated regime, fMRI experiments with a motor task revealed that the 3D variant outperforms the 2D-EPI in terms of temporal SNR and sensitivity to detect activated brain regions. Thus, the theoretical SNR advantage of a segmented 3D-EPI sequence for fMRI only exists in a low SNR situation. However, other advantages of 3D-EPI, such as the application of parallel imaging techniques in two dimensions and the low specific absorption rate requirements, may encourage the use of the 3D-EPI sequence for fMRI in situations with higher SNR

Correlation Entropy of an Interacting Quantum Field and H-theorem for the O(N) Model

Following the paradigm of Boltzmann-BBGKY we propose a correlation entropy (of the nth order) for an interacting quantum field, obtained by `slaving' (truncation with causal factorization) of the higher (n+1 th) order correlation functions in the Schwinger-Dyson system of equations. This renders an otherwise closed system effectively open where dissipation arises. The concept of correlation entropy is useful for addressing issues related to thermalization. As a small yet important step in that direction we prove an H-theorem for the correlation entropy of a quantum mechanical O(N) model with a Closed Time Path Two Particle Irreducible Effective Action at the level of Next-to-Leading-Order large N approximation. This model may be regarded as a field theory in $0$ space dimensions.Comment: 22 page

Tetra­kis-μ-l-alanine-κ8 O:O′-bis­[tetra­aqua­terbium(III)] hexa­perchlorate

The asymmetric unit of the title compound, [Tb2(C3H7NO2)4(H2O)8](ClO4)6, contains a dinuclear cation and six perchlorate anions, one of which is disordered. In the cation, the four l-alanine mol­ecules are present in their zwitterionic form and bridge two Tb3+ ions through their carboxyl­ate O atoms. Each Tb atom is also coordinated by four water mol­ecules in a square-anti­prismatic geometry. In the crystal structure, the cations and anions are held together via inter­molecular O—H⋯O and N—H⋯O hydrogen bonds

Hospitalized poisonings after renal transplantation in the United States

BACKGROUND: The national incidence of and risk factors for hospitalized poisonings in renal transplant recipients has not been reported. METHODS: Historical cohort study of 39,628 renal transplant recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. Associations with time to hospitalizations for a primary diagnosis of poisonings (ICD-9 codes 960.x-989.x) within three years after renal transplant were assessed by Cox Regression. RESULTS: The incidence of hospitalized poisonings was 2.3 patients per 1000 person years. The most frequent causes of poisonings were immunosuppressive agents (25.3%), analgesics/antipyretics (14.1%), psychotropic agents (10.0%), and insulin/antidiabetic agents (7.1%). In Cox Regression analysis, low body mass index (BMI, <21.6 vs. >28.3 kg/m(2), adjusted hazard ratio (AHR), 3.02, 95% CI, 1.45–6.28, and allograft rejection, AHR 1.83, 95% CI, 1.15–2.89, were the only factors independently associated with hospitalized poisonings. Hospitalized poisonings were independently associated with increased mortality (AHR, 1.54, 95% CI 1.22–1.92, p = 0.002). CONCLUSIONS: Hospitalized poisonings were associated with increased mortality after renal transplantation. However, almost all reported poisonings in renal transplant recipients were due to the use of prescribed medications. Allograft rejection and low BMI were the only independent risk factors for poisonings identified in this population

Inner ear hair cells produced in vitro by a mesenchymal-to-epithelial transition

Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of National academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 16675-16680, doi:10.1073/pnas.0704576104.Sensory hair cell loss is a major contributor to disabling hearing and balance deficits that affect >250 million people worldwide. Sound exposures, infections, drug toxicity, genetic disorders, and aging all can cause hair cell loss and lead to permanent sensory deficits. Progress toward treatments for these deficits has been limited, in part because hair cells have only been obtainable via microdissection of the anatomically complex internal ear. Attempts to produce hair cells in vitro have resulted in reports of some success, but have required transplantation into embryonic ears or co-culturing with other tissues. Here we show that avian inner ear cells can be cultured and passaged for months, frozen, and expanded to large numbers without other tissues. At any point from passage 6 up to at least passage 23, these cultures can be fully dissociated and then aggregated in suspension to induce a mesenchymal-to-epithelial transition that reliably yields new polarized sensory epithelia. Those epithelia develop numerous hair cells that are crowned by hair bundles, comprised of a single kinocilium and an asymmetric array of stereocilia. These hair cells exhibit rapid permeance to FM1-43, a dye that passes through open mechanotransducing channels. Since a vial of frozen cells can now provide the capacity to produce bona fide hair cells completely in vitro, these discoveries should open new avenues of research that may ultimately contribute to better treatments for hearing loss and other inner ear disorders.Supported by NIH grants DC00200 and DC006182to J.T.C

Representations of sport in the revolutionary socialist press in Britain, 1988–2012

This paper considers how sport presents a dualism to those on the far left of the political spectrum. A long-standing, passionate debate has existed on the contradictory role played by sport, polarised between those who reject it as a bourgeois capitalist plague and those who argue for its reclamation and reformation. A case study is offered of a political party that has consistently used revolutionary Marxism as the basis for its activity and how this party, the largest in Britain, addresses sport in its publications. The study draws on empirical data to illustrate this debate by reporting findings from three socialist publications. When sport did feature it was often in relation to high profile sporting events with a critical tone adopted and typically focused on issues of commodification, exploitation and alienation of athletes and supporters. However, readers’ letters, printed in the same publications, revealed how this interpretation was not universally accepted, thus illustrating the contradictory nature of sport for those on the far left

Isolation and characterization of neural crest progenitors from adult dorsal root ganglia

After peripheral nerve injury, the number of sensory neurons in the adult dorsal root ganglia (DRG) is initially reduced but recovers to a normal level several months later. The mechanisms underlying the neuronal recovery after injury are not clear. Here, we showed that in the DRG explant culture, a subpopulation of cells that emigrated out from adult rat DRG expressed nestin and p75 neurotrophin receptor and formed clusters and spheres. They differentiated into neurons, glia, and smooth muscle cells in the presence or absence of serum and formed secondary and tertiary neurospheres in cloning assays. Molecular expression analysis demonstrated the characteristics of neural crest progenitors and their potential for neuronal differentiation by expressing a set of well-defined genes related to adult stem cells niches and neuronal fate decision. Under the influence of neurotrophic factors, some of these progenitors gave rise to neuropeptide-expressing cells and protein zero-expressing Schwann cells. In a 5-bromo-2′-deoxyuridine chasing study, we showed that these progenitors likely originate from satellite glial cells. Our study suggests that a subpopulation of glia in adult DRG is likely to be progenitors for neurons and glia and may play a role in neurogenesis after nerve injury. ©AlphaMed Press

Vitamin K Supplementation in Postmenopausal Women with Osteopenia (ECKO Trial): A Randomized Controlled Trial

Angela Cheung and colleagues investigate whether vitamin K1 can prevent bone loss among postmenopausal women with osteopenia

A Precision Determination of the D^0 Mass

A precision measurement of the D^0 meson mass has been made using ~281 pb-1 of e+e- annihilation data taken with the CLEO-c detector at the psi(3770) resonance. The exclusive decay D^0 -> (Ks phi) has been used to obtain M(D^0)=1864.847+-0.150(stat)+-0.095(syst) MeV. This corresponds to M(D^0 D^*0)=3871.81+-0.36 MeV, and leads to a well-constrained determination of the binding energy of the proposed (D^0 D^*0) molecule X(3872), E_b=0.6+-0.6 MeV.Comment: 8 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2006/, Submitted to PR

Adherence challenges encountered in an intervention programme to combat chronic non-communicable diseases in an urban black community, Cape Town

Background: Chronic non-communicable diseases (CNCD) have become the greatest contributor to the mortality rate worldwide. Despite attempts by Governments and various non-governmental organisations to prevent and control the epidemic with various intervention strategies, the number of people suffering from CNCD is increasing at an alarming rate in South Africa and worldwide. Objectives: Study's objectives were to explore perceived challenges with implementation of, and adherence to health messages disseminated as part of a CNCD intervention programme; to gain an understanding of participants' expectations of CNCD intervention programmes;, and to explore the acceptability and preference of health message dissemination methods. In addition, participants' awareness of, and willingness to participate in CNCDs intervention programmes in their community was explored. Methods: Participants were recruited from the existing urban Prospective Urban Rural Epidemiology study site in Langa, Cape Town. Focus group discussions were conducted with 47 participants using a question guide. Summative content analysis was used to analyse the data. Results: Four themes emerged from the data analysis: practical aspects of implementation and adherence to intervention programmes; participants' expectations of intervention programmes; aspects influencing participants' acceptance of interventions; and their preferences for health message dissemination. The results of this study will be used to inform CNCDs intervention programmes. Conclusions: Our findings revealed that although participants found current methods of health message dissemination in CNCDs intervention acceptable, they faced real challenges with implementing and adhering to CNCDs to these messages.DHE