Determination of the

We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010 GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157 GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15 fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15 fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.

Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering.

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

Micelle response to changes in solvent properties.

The dynamics of co-polymer systems play an important role in the preparation and stability of formulations, as well as on their capability to function in drug delivery systems. Micelle inversion can occur as a result of a change in concentration when a solvent is very volatile and evaporates, or as a result of a change in solvent quality upon addition of another solvent to the original solution, or upon changes in pH. In this work, dissipative particle dynamics (DPD) is used to examine the dynamics of micelle inversion in concentrated systems of diblock and triblock amphiphiles, where interactions between neighboring aggregates are observed. Significant differences were observed in the inversion process of different amphiphilic molecules, with a large amount of co-polymer exchange between inverting aggregates made of diblock amphiphiles, and practically no exchange of molecules between aggregates during the inversion of triblock copolymer aggregates. Fundamental mechanisms of inversion are revealed that provide information which can be used to help design micelles for targeted drug release and allow understanding of history dependant formulations.

AST/ASTS workshop on increasing organ donation in the United States: creating an "arc of change" from removing disincentives to testing incentives.

The American Society of Transplantation (AST) and American Society of Transplant Surgeons (ASTS) convened a workshop on June 2-3, 2014, to explore increasing both living and deceased organ donation in the United States. Recent articles in the lay press on illegal organ sales and transplant tourism highlight the impact of the current black market in kidneys that accompanies the growing global organ shortage. We believe it important not to conflate the illegal market for organs, which we reject in the strongest possible terms, with the potential in the United States for concerted action to remove all remaining financial disincentives for donors and critically consider testing the impact and acceptability of incentives to increase organ availability in the United States. However, we do not support any trials of direct payments or valuable considerations to donors or families based on a process of market-assigned values of organs. This White Paper represents a summary by the authors of the deliberations of the Incentives Workshop Group and has been approved by both AST and ASTS Boards.

Loss of pediatric kidney grafts during the "high-risk age window": insights from pediatric liver and simultaneous liver-kidney recipients.

Pediatric kidney transplant recipients experience a high-risk age window of increased graft loss during late adolescence and early adulthood that has been attributed primarily to sociobehavioral mechanisms such as nonadherence. An examination of how this age window affects recipients of other organs may inform the extent to which sociobehavioral mechanisms are to blame or whether kidney-specific biologic mechanisms may also exist. Graft loss risk across current recipient age was compared between pediatric kidney (n = 17,446), liver (n = 12,161) and simultaneous liver-kidney (n = 224) transplants using piecewise-constant hazard rate models. Kidney graft loss during late adolescence and early adulthood (ages 17-24 years) was significantly greater than during ages <17 (aHR = 1.79, 95%CI = 1.69-1.90, p < 0.001) and ages >24 (aHR = 1.11, 95%CI = 1.03-1.20, p = 0.005). In contrast, liver graft loss during ages 17-24 was no different than during ages <17 (aHR = 1.03, 95%CI = 0.92-1.16, p = 0.6) or ages >24 (aHR = 1.18, 95%CI = 0.98-1.42, p = 0.1). In simultaneous liver-kidney recipients, a trend towards increased kidney compared to liver graft loss was observed during ages 17-24 years. Late adolescence and early adulthood are less detrimental to pediatric liver grafts compared to kidney grafts, suggesting that sociobehavioral mechanisms alone may be insufficient to create the high-risk age window and that additional biologic mechanisms may also be required.

Identifying Opportunities for Virtual Reality Simulation in Surgical Education: A Review of the Proceedings from the Innovation, Design, and Emerging Alliances in Surgery (IDEAS) Conference: VR Surgery.

OBJECTIVES: To conduct a review of the state of virtual reality (VR) simulation technology, to identify areas of surgical education that have the greatest potential to benefit from it, and to identify challenges to implementation. BACKGROUND DATA: Simulation is an increasingly important part of surgical training. VR is a developing platform for using simulation to teach technical skills, behavioral skills, and entire procedures to trainees and practicing surgeons worldwide. Questions exist regarding the science behind the technology and most effective usage of VR simulation. A symposium was held to address these issues. METHODS: Engineers, educators, and surgeons held a conference in November 2013 both to review the background science behind simulation technology and to create guidelines for its use in teaching and credentialing trainees and surgeons in practice. RESULTS: Several technologic challenges were identified that must be overcome in order for VR simulation to be useful in surgery. Specific areas of student, resident, and practicing surgeon training and testing that would likely benefit from VR were identified: technical skills, team training and decision-making skills, and patient safety, such as in use of electrosurgical equipment. CONCLUSIONS: VR simulation has the potential to become an essential piece of surgical education curriculum but depends heavily on the establishment of an agreed upon set of goals. Researchers and clinicians must collaborate to allocate funding toward projects that help achieve these goals. The recommendations outlined here should guide further study and implementation of VR simulation.

Olly Olly Oxen Free (or Ally Ally in Free): Playing Hide and Seek in Allocating Resources for Child and Youth Health.

There are powerful arguments for increased investment in child and youth health. But the extent to which these benefits can be realized is shaped by health institutions' priority setting processes. We asked, "What are the unique features of a pediatric care setting that should influence choice and implementation of a formal priority setting and resource allocation process?" Based on multiple sources of data, we created a "made-for-child-health" lens containing three foci reflective of the distinct features of pediatric care settings: the diversity of child and youth populations, the challenges in measuring outcomes and the complexity of patient and public engagement.

The economic cost of nonepileptic attack disorder in Ireland.

The present study endeavored to calculate a conservative estimate of both incidence- and prevalence-based costs of nonepileptic attack disorder (NEAD) in Ireland by applying previously identified prevalence figures to Irish population figures. Variables related to the economic cost of NEAD were identified based on a retrospective chart review of patients diagnosed with NEAD at Beaumont Hospital, Dublin. The annual cost per patient of undiagnosed NEAD was calculated as €20,995.30. The combined cost of diagnosis and psychological treatment of NEAD was estimated at €8728. Although it is difficult to determine precise economic costings, early diagnosis and intervention would result in a significant economic saving to the exchequer, a reduction in hospital waiting-list times, and a better prognosis for patients.

First determination of the weak charge of the proton.

The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 µA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.

Beaufort trout MicroPlex: a high-throughput multiplex platform comprising 38 informative microsatellite loci for use in resident and anadromous (sea trout) brown trout Salmo trutta genetic studies.

A flexible panel consisting of 38 informative microsatellite markers for Salmo trutta is described. These markers were selected from a pool of over 150 candidate loci that can be readily amplified in four multiplex PCR groups but other permutations are also possible. The basic properties of each markers were assessed in six population samples from both the Burrishoole catchment, in the west of Ireland, and Lough Neagh, in Northern Ireland. A method to assess the relative utility of individual markers for the detection of population genetic structuring is also described. Given its flexibility, technical reliability and high degree of informativeness, the use of this panel of markers is advocated as a standard for S. trutta genetic studies.

Assessment of eye and body dose for interventional radiologists, cardiologists, and other interventional staff.

A dose limit for the eye of 20 mSv, as proposed by the ICRP, could be exceeded by interventional clinicians. Data on eye dose levels for interventional radiologists and cardiologists provided by medical physicists from hospitals around the UK have been collated. The results indicate that most hospitals would require one or more interventional clinicians to be classified and several would have exceeded a 20 mSv limit. Dose data in the literature have been reviewed to derive factors that might be used to predict eye dose levels based on dose per procedure or kerma-area product workload. These could be used in prior risk assessments to establish monitoring practice. An alternative approach to personnel dose monitoring in radiology applications using a collar dosimeter worn outside the lead apron as the first dosimeter is proposed. The collar dosimeter would provide an assessment of eye dose in terms of Hp(3) and body dose in terms of Hp(10), which could be divided by ten to provide an assessment of effective dose. If Hp(3) exceeded 1 mSv per month, regular monitoring with a head dosimeter would be recommended, and if Hp(10) exceeded 2 mSv per month, then an under-apron dosimeter should also be worn.

Changing epidemiology of Clostridium difficile infection following the introduction of a national ribotyping-based surveillance scheme in England.

BACKGROUND: Marked increases in Clostridium difficile infection (CDI) incidence, driven by epidemic strain spread, is a global phenomenon. METHODS: The Clostridium difficile Ribotyping Network (CDRN) was established in 2007 as part of enhanced CDI surveillance in England, to facilitate the recognition and control of epidemic strains. We report on changes in CDI epidemiology in England in the first 3 years of CDRN. RESULTS: CDRN received 12,603 fecal specimens, comprising significantly (P < .05) increasing numbers and proportions of national CDI cases in 2007-2008 (n = 2109, 3.8%), 2008-2009 (n = 4774, 13.2%), and 2009-2010 (n = 5720, 22.3%). The C. difficile recovery rate was 90%, yielding 11,294 isolates for ribotyping. Rates of 9 of the 10 most common ribotypes changed significantly (P < .05) during 2007-2010. Clostridium difficile ribotype 027 predominated, but decreased markedly from 55% to 36% and 21% in 2007-2008, 2008-2009, and 2009-2010, respectively. The largest regional variations in prevalence occurred for ribotypes 027, 002, 015, and 078. Cephalosporin and fluoroquinolone use in CDI cases was reported significantly (P < .05) less frequently during 2007-2010. Mortality data were subject to potential reporting bias, but there was a significant decrease in CDI-associated deaths during 2007-2010, which may have been due to multiple factors, including reduced prevalence of ribotype 027. CONCLUSIONS: Access to C. difficile ribotyping was associated with significant changes in the prevalence of epidemic strains, especially ribotype 027. These changes coincided with markedly reduced CDI incidence and related mortality in England. CDI control programs should include prospective access to C. difficile typing and analysis of risk factors for CDI and outcomes.

Reducing pediatric liver transplant complications: a potential roadmap for transplant quality improvement initiatives within North America.

Though robust clinical data are available within transplantation, these data are not used for broad-based, multicentered quality improvement initiates. This article describes a targeted quality improvement initiative within the Studies of Pediatric Liver Transplantation (SPLIT) Registry. Using standard statistical techniques and clinical expertise to adjust for data and statistical reliability, we identified the pediatric liver transplant centers in North America with the lowest hepatic artery thrombosis rate and biliary complication rates. A survey was completed to establish current practices within the entire SPLIT group. Surgeons from the highest performing centers presented a detailed, technically oriented overview of their current practices. The presentations and discussion that followed were recorded and form the basis of the best practices described herein. We frame this work as a unique six-step approach roadmap that may serve as an efficient and cost effective model for novel broad-based quality improvement initiatives within transplantation.

Derivation of factors for estimating the scatter of diagnostic x-rays from walls and ceiling slabs.

Computed tomography (CT) scanning rooms and interventional x-ray facilities with heavy workloads may require the installation of shielding to protect against radiation scattered from walls or ceiling slabs. This is particularly important for the protection of those operating x-ray equipment from within control cubicles who may be exposed to radiation scattered from the ceiling over the top of the protective barrier and round the side if a cubicle door is not included. Data available on the magnitude of this tertiary scatter from concrete slabs are limited. Moreover, there is no way in which tertiary scatter levels can be estimated easily for specific facilities. There is a need for a suitable method for quantification of tertiary scatter because of the increases in workloads of complex x-ray facilities. In this study diagnostic x-ray air kerma levels scattered from concrete and brick walls have been measured to verify scatter factors. The results have been used in a simulation of tertiary scatter for x-ray facilities involving summation of scatter contributions from elements across concrete ceiling slabs. The majority of the ceiling scatter air kerma to which staff behind a barrier will be exposed arises from the area between the patient/x-ray tube and the staff. The level depends primarily on the heights of the ceiling and protective barrier. A method has been developed to allow tertiary scatter levels to be calculated using a simple equation based on a standard arrangement for rooms with different ceiling and barrier heights. Coefficients have been derived for a CT facility and an interventional suite to predict tertiary scatter levels from the workload, so that consideration can be given to the protection options available.

Transplant surgery fellow perceptions about training and the ensuing job market-are the right number of surgeons being trained?

The American Society of Transplant Surgeons (ASTS) sought whether the right number of abdominal organ transplant surgeons are being trained in the United States. Data regarding fellowship training and the ensuing job market were obtained by surveying program directors and fellowship graduates from 2003 to 2005. Sixty-four ASTS-approved programs were surveyed, representing 139 fellowship positions in kidney, pancreas and/or liver transplantation. One-quarter of programs did not fill their positions. Forty-five fellows graduated annually. Most were male (86%), aged 31-35 years (57%), married (75%) and parents (62%). Upon graduation, 12% did not find transplant jobs (including 8% of Americans/Canadians), 14% did not get jobs for transplanting their preferred organ(s), 11% wished they focused more on transplantation and 27% changed jobs early. Half fellows were international medical graduates; 45% found US/Canadian transplant jobs, particularly 73% with US/Canadian residency training. Fellows reported adequate exposure to training volume, candidate selection, pre/postoperative care and organ procurement, but not to donor management/selection, outpatient care and core didactics. One-sixth noted insufficient 'mentoring/preparation for a transplantation career'. Currently, there seem to be enough trainees to fill entry-level positions. One-third program directors believe that there are too many trainees, given the current and foreseeable job market. ASTS is assessing the total workforce of transplant surgeons and evolving manpower needs.

Implementation of vascularized composite allografts in the United States: recommendations from the ASTS VCA Ad Hoc Committee and the Executive Committee.

Like all other areas of transplantation, vascularized composite allografts (VCA) has the capacity to transform the lives of patients, for the better or for the worse. It is this duality that mandates VCA be performed in centers prepared for the intricacies accompanying other transplant procedures. Similarly, the complexities of VCA require that the procedures be driven by surgeons and physicians with experience in the multidisciplinary management of immunocompromised postsurgical patients. Furthermore, the grafts should be considered as organs rather than tissues from a regulatory and a biological standpoint. The ASTS supports the field of VCA and has demonstrated its support and leadership by actively formulating a strategy for its systematic development. The goal of this document is to provide a framework for the prospective, thoughtful realization of VCA in the United States from the American Society of Transplant Surgeons (ASTS) perspective.

Molecular epidemiology of Mycobacterium tuberculosis in East Lancashire 2001-2009.

BACKGROUND: East Lancashire has had high rates of tuberculosis for 40 years. The ethnically diverse population is predominantly of South Asian and white origin. Drug resistance data from 1960 to 1999 indirectly suggest that no significant inter-ethnic transmission has occurred. This study used mycobacterial interspersed repetitive unit variable number tandem repeat (MIRU-VNTR) fingerprinting to assess clustering within and between ethnic groups. METHODS: All isolates of Mycobacterium tuberculosis from January 2001 to July 2009 from East Lancashire postcode areas were MIRU-VNTR fingerprinted. Clusters of strains with indistinguishable profiles were also assessed epidemiologically, and their MIRU-VNTR profiles compared with the UK M tuberculosis Strain Typing Database. RESULTS: 332 strains were typed (63 white patients, and 269 non-white patients). 198 MIRU-VNTR profiles were identified, with 144 profiles occurring only once. The typing clustered 187 strains into 53 clusters indistinguishable at all 12 loci and these were further characterised using the exact tandem repeat loci A, B, and C. The 15 loci clustered 32/63 (50.8%) of white and 110/269 (40.9%) of non-white cases and all but nine clusters were of the same ethnicity. The nine inter-racial clusters were further assessed from an epidemiological and clinical perspective and fingerprinting using nine additional loci. Isolates within two of the clusters were further discriminated using the additional nine loci. However, the additional loci did not further discriminate the isolates in the other seven inter-racial clusters. CONCLUSIONS: MIRU-VNTR fingerprinting indicates that although there is evidence of a high rate of transmission within the South Asian sub-population, the data suggest that there is little inter-ethnic transmission.

Parental views on tissue banking in pediatric oncology patients.

PURPOSE: Research using banked tissue is key to advancing risk-stratification and treatment of children with cancer. Knowledge of parental attitudes to ethical issues arising in tissue banking is very limited but essential in obtaining respectful consent. METHODS: One hundred parents of consecutively diagnosed children with cancer were offered a validated 34-item questionnaire. RESULTS: Respondents (n = 54) included 10 of 16 parents of deceased children. The majority (89%; n = 48) would agree to have tissue sent anywhere in the world but prefer pediatric aims (69%). Most (98%; n = 53) would permit genetic research, if it might improve the child's health, and 76% (n = 41) would permit it, even if no impact was anticipated. A minority (41%) would not allow painful, strictly research procedures, while 15% would regardless of the child's dissent. Just over half (54%; n = 29) wish to renew consent if stored tissue is used for another purpose. Most (98%) believe their child should confirm consent by the age of majority, but only 71% believe the mature child should be able to withdraw consent. A minority (n = 40; 74%) claim few or no rights to research profits; 83% believe these should be used to fund childhood cancer research. CONCLUSIONS: Parents are very supportive of tissue research, including genetic research. A majority of parents would prefer restricting research to pediatric conditions, and to be informed of results, even if of uncertain significance. These findings may assist Institutional Review Boards in assessing parentally perceived risks of research, and researchers in providing consent elements that support parents and adolescents in making fully informed choices.

Improved differentiation of Mycobacterium tuberculosis isolates in the north of England using additional variable number tandem repeat loci.

Mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) genotyping of over 3300 Mycobacterium tuberculosis isolates from the north of England has identified large clusters of strains which share common profiles. However, many apparent clusters identified when typed using the existing 15 loci lack clear epidemiological links. This study seeks to discover whether or not six additional VNTR loci can increasethe discriminatory power of the existing MIRU-VNTR 15-loci technique. Two hundred and six M. tuberculosis isolates were genotyped, including 57 isolates from 20 epidemiologically linked clusters and 149 from unlinked patients belonging to six large MIRU-VNTR-defined clusters. The discriminatory power of the six additional loci was high (Hunter Gaston Discriminatory Index [HGDI]: 0.952). Five of the six loci were highly discriminative (h > 0.6); however, locus 2401 was less discriminative (h = 0.5). The additional VNTR loci were able to subtype all six unlinked common MIRU-VNTR clusters into 56 subclusters, significantly differentiating unrelated strains in a set previously incorrectly clustered using 15 MIRU-VNTR loci. The largest cluster size was 14 (9.3%) when typed using the six additional VNTR loci, compared to 30 (20%) when typed using the original 15 MIRU-VNTR loci. The same loci were also found to be stable as a result of their inability to subdivide any of the epidemiologically linked clusters. This study has demonstrated that expanding the MIRU-VNTR panel beyond the 15 previously used loci significantly increases the discriminatory power of the technique and thus provides a valuable tool in the epidemiological monitoring of this disease.

Glomerular filtration rate following pediatric liver transplantation--the SPLIT experience.

Impaired kidney function is a well-recognized complication following liver transplantation (LT). Studies of this complication in children have been limited by small numbers and insensitive outcome measures. Our aim was to define the prevalence of, and identify risk factors for, post-LT kidney dysfunction in a multicenter pediatric cohort using measured glomerular filtration rate (mGFR). We conducted a cross-sectional study of 397 patients enrolled in the Studies in Pediatric Liver Transplantation (SPLIT) registry, using mGFR < 90 mL/min/1.73 m(2) as the primary outcome measure. Median age at LT was 2.2 years. Primary diagnoses were biliary atresia (44.6%), fulminant liver failure (9.8%), metabolic liver disease (16.4%), chronic cholestatic liver disease (13.1%), cryptogenic cirrhosis (4.3%) and other (11.8%). At a mean of 5.2 years post-LT, 17.6% of patients had a mGFR < 90 mL/min/1.73 m(2) . In univariate analysis, factors associated with this outcome were transplant center, age at LT, primary diagnosis, calculated GFR (cGFR) at LT and 12 months post-LT, primary immunosuppression, early post-LT kidney complications, age at mGFR, height and weight Z-scores at 12 months post-LT. In multivariate analysis, independent variables associated with a mGFR <90 mL/min/1.73 m(2) were primary immunosuppression, age at LT, cGFR at LT and height Z-score at 12 months post-LT.