A novel two‐beam accelerator (twobetron)

A new configuration is analyzed wherein a low current beam is accelerated to high energies (10’s of amps, 10’s of MeV) by a driver beam of high current and low energy (a few kiloamps, <1 MeV). The annular driver beam excites the TM020 cavity mode of an accelerating structure which transfers its rf power to the on‐axis secondary beam. Systematic variation of the driver beam radius provides the secondary beam with phase focusing and adjustable acceleration gradient. A proof‐of‐principle experiment is suggested. Various issues, such as the scaling laws, transverse and longitudinal instabilities, rf coupling among cavities, etc., are examined. © 1995 American Institute of PHysics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87548/2/451_1.pd

Duty Hour Reform and the Outcomes of Patients Treated by New Surgeons

Despite concerns that duty hour reform might adversely affect the performance of new surgeons, this national study found no impact on patient outcomes, including 30-day mortality rates, failure-to-rescue, length of stay, and use of intensive care units. These findings should allay fears that reduced work hours during residency would produce surgeons less prepared for practice than their more experienced colleagues

Relative efficacy of topical non-steroidal anti-inflammatory drugs and topical capsaicin in osteoarthritis: protocol for an individual patient data meta-analysis

Background Pain is the most troubling issue to patients with osteoarthritis (OA), yet current pharmacological treatments offer only small-to-moderate pain reduction. Current guidelines therefore emphasise the need to identify predictors of treatment response. In line with these recommendations, an individual patient data (IPD) meta-analysis will be conducted. The study aims to investigate the relative treatment effects of topical non-steroidal anti-inflammatory drugs (NSAIDs) and topical capsaicin in OA and to identify patient-level predictors of treatment response. Methods IPD will be collected from randomised controlled trials (RCTs) of topical NSAIDs and capsaicin in OA. Multilevel regression modelling will be conducted to determine predictors for the specific and the overall treatment effect. Discussion Through the identification of treatment responders, this IPD meta-analysis may improve the current understanding of the pain mechanisms in OA and guide clinical decision-making. Identifying and prescribing the treatment most likely to be beneficial for an individual with OA will improve the efficiency of patient management

Gastroesophageal reflux disease in 2006: The imperfect diagnosis

There continues to be significant controversy related to diagnostic testing for gastroesophageal reflux disease (GERD). Clearly, barium contrast fluoroscopy is superior to any other test in defining the anatomy of the upper gastrointestinal (UGI) tract. Although fluoroscopy can demonstrate gastroesophageal reflux (GER), this observation does not equate to GERD. Fluoroscopy time should not be prolonged to attempt to demonstrate GER during barium contrast radiography. There are no data to justify prolonging fluoroscopy time to perform provocative maneuvers to demonstrate reflux during barium contrast UGI series. Symptoms of GERD may be associated with physiologic esophageal acid exposure measured by intraesophageal pH monitoring, and a significant percentage of patients with abnormal esophageal acid exposure have no or minimal clinical symptoms of reflux. Abnormal acid exposure defined by pH monitoring over a 24-h period does not equate to GERD. In clinical practice presumptive diagnosis of GERD is reasonably assumed by substantial reduction or elimination of suspected reflux symptoms during therapeutic trial of acid reduction therapy

Neocortical hyperexcitability in a genetic model of absence seizures and its reduction by levetiracetam

PURPOSE: To study the effect of the antiepileptic drug levetiracetam (LEV) on the patterns of intrinsic optical signals (IOSs) generated by slices of the somatosensory cortex obtained from 3- and 6-month-old WAG/Rij and age-matched, nonepileptic control (NEC) rats. METHODS: WAG/Rij and NEC animals were anesthetized with enfluorane and decapitated. Brains were quickly removed, and neocortical slices were cut coronally with a vibratome, transferred to a submerged tissue chamber, and superfused with oxygenated artificial cerebrospinal fluid (aCSF). Slices were illuminated with a dark-field condensor and examined with a x2.5 objective; images were processed with a real time digital video image-enhancement system. Images were acquired before (background) and during electrical stimulation with a temporal resolution of 10 images/s and were displayed in pseudocolors. Extracellular stimuli (200 micros; <4 V) were delivered through bipolar stainless steel electrodes placed in the white matter. RESULTS: IOSs recorded in NEC slices bathed in control aCSF became less intense and of reduced size with age (p < 0.05); this trend was not seen in WAG/Rij slices. Age-dependent decreases in IOS intensity and area size were also seen in NEC slices superfused with aCSF containing the convulsant 4-aminopyridine (4-AP, 5 microM); in contrast, significant increases in both parameters occurred with age in 4-AP-treated WAG/Rij slices (p < 0.05). Under any of these conditions, the IOS intensity and area size slices were larger in WAG/Rij than in NEC slices. LEV (50-500 microM) application to WAG/Rij slices caused dose-dependent IOS reductions that were evident both in control and in 4-AP-containing aCSF and were more pronounced in 6-month-old tissue. CONCLUSIONS: These data demonstrate age-dependent IOS modifications in NEC and WAG/Rij rat slices and identify a clear pattern of hyperexcitability that occurs in 6-month-old WAG/Rij neocortical tissue, an age when absence seizures occur in all animals. The ability of LEV to reduce these patterns of network hyperexcitability supports the potential use of this new antiepileptic drug in primary generalized epileptic disorders

Diagnosis, extent, impacts, and management of subsoil constraints in the northern grains cropping region of Australia

Productivity of grain crops grown under dryland conditions in north-eastern Australia depends on efficient use of rainfall and available soil moisture accumulated in the period preceding sowing. However, adverse subsoil conditions including high salinity, sodicity, nutrient imbalances, acidity, alkalinity, and high concentrations of chloride (Cl) and sodium (Na) in many soils of the region restrict ability of crop roots to access this stored water and nutrients. Planning for sustainable cropping systems requires identification of the most limiting constraint and understanding its interaction with other biophysical factors. We found that the primary effect of complex and variable combinations of subsoil constraints was to increase the crop lower limit (CLL), thereby reducing plant available water. Among chemical subsoil constraints, subsoil Cl concentration was a more effective indicator of reduced water extraction and reduced grain yields than either salinity or sodicity (ESP). Yield penalty due to high subsoil Cl was seasonally variable, with more in-crop rainfall (ICR) resulting in less negative impact. A conceptual model to determine realistic yield potential in the presence of subsoil Cl was developed from a significant positive linear relationship between CLL and subsoil Cl:Since grid sampling of soil to identify distribution of subsoil Cl, both spatially across landscape and within soil profile, is time-consuming and expensive, we found that electromagnetic induction, coupled with yield mapping and remote sensing of vegetation offers potential to rapidly identify possible subsoil Cl at paddock or farm scale.Plant species and cultivars were evaluated for their adaptations to subsoil Cl. Among winter crops, barley and triticale, followed by bread wheat, were more tolerant of high subsoil Cl concentrations than durum wheat. Chickpea and field pea showed a large decrease in yield with increasing subsoil Cl concentrations and were most sensitive of the crops tested. Cultivars of different winter crops showed minor differences in sensitivity to increasing subsoil Cl concentrations. Water extraction potential of oilseed crops was less affected than cereals with increasing levels of subsoil Cl concentrations. Among summer crops, water extraction potential of millet, mungbean, and sesame appears to be more sensitive to subsoil Cl than that of sorghum and maize; however, the differences were significant only to 0.7 m. Among pasture legumes, lucerne was more tolerant to high subsoil Cl concentrations than the others studied.Surface applied gypsum significantly improved wheat grain yield on soils with ESP >6 in surface soil (0–0.10 m). Subsurface applied gypsum at 0.20–0.30 m depth did not affect grain yield in the first year of application; however, there was a significant increase in grain yield in following years. Better subsoil P and Zn partially alleviated negative impact of high subsoil Cl. Potential savings from improved N fertilisation decisions for paddocks with high subsoil Cl are estimated at ~$AU10 million per annum

Prognostic value of hedgehog signal component expressions in hepatoblastoma patients

<p>Abstract</p> <p>Objective</p> <p>Activation of hedgehog (Hh) pathway has been implicated in the development of human malignancies. Hh as well as related downstream target genes has been extensively studied in many kinds of malignant tumours for clinical diagnostic or prognostic utilities. This study aimed at investigating whether Hh molecules provides a molecular marker of hepatoblastoma malignancy.</p> <p>Methods</p> <p>We obtained tissue sections from 32 patients with hepatoblastoma as well as cholestasis and normal control. Immunohistochemical analysis were performed to determine Hh signal components in human hepatoblastoma. The prognostic significance of single expression of Hh signal components were evaluated using Cox proportional hazards regression models and Kaplan-Meier survival analysis for statistical analysis.</p> <p>Results</p> <p>Expression of Hh signal components showed an increase in hepatoblastoma compared with chole stasis and normal tissues. There was a positive correlation between Smo or Gli1 expression and tumor clinicopathological features, such as histological type, tumor grade, tumor size and clinical stage. Both Smo or Gli1 protein high expression was significantly associated with poor prognosis by univariate analyses and multivariate analyses.</p> <p>Conclusions</p> <p>Abnormal Hh signaling activation plays important roles in the malignant potential of hepatoblastoma. Gli1 expression is an independent prognostic marker.</p

Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA

The exclusive deep inelastic electroproduction of $\psi(2S)$ and $J/\psi(1S)$ at an $ep$ centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range $2 < Q^2 < 80$ GeV$^2$, $30 < W < 210$ GeV and $|t| < 1$ GeV$^2$, where $Q^2$ is the photon virtuality, $W$ is the photon-proton centre-of-mass energy and $t$ is the squared four-momentum transfer at the proton vertex. The data for $2 < Q^2 < 5$ GeV$^2$ were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb$^{-1}$. The data for $5 < Q^2 < 80$ GeV$^2$ are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb$^{-1}$. The decay modes analysed were $\mu^+\mu^-$ and $J/\psi(1S) \,\pi^+\pi^-$ for the $\psi(2S)$ and $\mu^+\mu^-$ for the $J/\psi(1S)$. The cross-section ratio $\sigma_{\psi(2S)}/\sigma_{J/\psi(1S)}$ has been measured as a function of $Q^2, W$ and $t$. The results are compared to predictions of QCD-inspired models of exclusive vector-meson production.Comment: 24 pages, 8 figure