An adjustable focusing system for a 2 MeV H- ion beam line based on permanent magnet quadrupoles

A compact adjustable focusing system for a 2 MeV H- RFQ Linac is designed, constructed and tested based on four permanent magnet quadrupoles (PMQ). A PMQ model is realised using finite element simulations, providing an integrated field gradient of 2.35 T with a maximal field gradient of 57 T/m. A prototype is constructed and the magnetic field is measured, demonstrating good agreement with the simulation. Particle track simulations provide initial values for the quadrupole positions. Accordingly, four PMQs are constructed and assembled on the beam line, their positions are then tuned to obtain a minimal beam spot size of (1.2 x 2.2) mm^2 on target. This paper describes an adjustable PMQ beam line for an external ion beam. The novel compact design based on commercially available NdFeB magnets allows high flexibility for ion beam applications.

Sampling strategies for capillary isoelectric focusing with electroosmotic zone mobilization assessed by high-resolution dynamic computer simulation

The impact of initial sample distribution on separation and focusing of analytes in a pH 3–11 gradient formed by 101 biprotic carrier ampholytes under concomitant electroosmotic displacement was studied by dynamic high-resolution computer simulation. Data obtained with application of the analytes mixed with the carrier ampholytes (as is customarily done), as a short zone within the initial carrier ampholyte zone, sandwiched between zones of carrier ampholytes, or introduced before or after the initial carrier ampholyte zone were compared. With sampling as a short zone within or adjacent to the carrier ampholytes, separation and focusing of analytes is shown to proceed as a cationic, anionic, or mixed process and separation of the analytes is predicted to be much faster than the separation of the carrier components. Thus, after the initial separation, analytes continue to separate and eventually reach their focusing locations. This is different to the double-peak approach to equilibrium that takes place when analytes and carrier ampholytes are applied as a homogenous mixture. Simulation data reveal that sample application between two zones of carrier ampholytes results in the formation of a pH gradient disturbance as the concentration of the carrier ampholytes within the fluid element initially occupied by the sample will be lower compared to the other parts of the gradient. As a consequence thereof, the properties of this region are sample matrix dependent, the pH gradient is flatter, and the region is likely to represent a conductance gap (hot spot). Simulation data suggest that sample placed at the anodic side or at the anodic end of the initial carrier ampholyte zone are the favorable configurations for capillary isoelectric focusing with electroosmotic zone mobilization.

Blinded by PRISMA: are systematic reviewers focusing on PRISMA and ignoring other guidelines?

BACKGROUND PRISMA guidelines have been developed to improve the reporting of systematic reviews (SRs). Other reporting guidelines and techniques to assess methodological quality of SRs have been developed. We aimed to assess the frequency of the use of reporting and other guidelines in SRs to assess whether PRISMA is being used inappropriately as a substitute for other relevant guidelines. METHODS Web of Knowledge was searched to identify articles citing the PRISMA guidelines over a 12-month period. The use of reporting guidelines (including PRISMA and MOOSE) and tools for assessing methodological quality (including QUADAS) was assessed. Factors associated with appropriate use of guidelines including review type, field of publication and involvement of a methodologist were investigated. RESULTS Over the 12-month period, 701 SRs were identified. MOOSE guidelines were cited in just 17% of epidemiologic reviews; QUADAS or QUADAS-2 was referred to in just 40% of diagnostic SRs. In the multivariable analysis, medical field of publication and methodologist involvement (OR = 1.97, 95% CI: 1.37, 2.83) were significant predictors of appropriate use of guidelines. Inclusion of a meta-analysis resulted in 73% higher odds of appropriate usage of systematic review guidelines (OR = 1.73, 95% CI: 1.22, 2.35). CONCLUSIONS Usage of SR reporting guidelines and tools for assessment of methodological quality other than PRISMA may be under-utilized with negative implications both for the reporting and methodological quality of systematic reviews.

Cone beam computed tomography in implant dentistry: a systematic review focusing on guidelines, indications, and radiation dose risks.

PURPOSE The aim of the paper is to identify, review, analyze, and summarize available evidence in three areas on the use of cross-sectional imaging, specifically maxillofacial cone beam computed tomography (CBCT) in pre- and postoperative dental implant therapy: (1) Available clinical use guidelines, (2) indications and contraindications for use, and (3) assessment of associated radiation dose risk. MATERIALS AND METHODS Three focused questions were developed to address the aims. A systematic literature review was performed using a PICO-based search strategy based on MeSH key words specific to each focused question of English-language publications indexed in the MEDLINE database retrospectively from October 31, 2012. These results were supplemented by a hand search and gray literature search. RESULTS Twelve publications were identified providing guidelines for the use of cross-sectional radiography, particularly CBCT imaging, for the pre- and/or postoperative assessment of potential dental implant sites. The publications discovered by the PICO strategy (43 articles), hand (12), and gray literature searches (1) for the second focus question regarding indications and contraindications for CBCT use in implant dentistry were either cohort or case-controlled studies. For the third question on the assessment of associated radiation dose risk, a total of 22 articles were included. Publication characteristics and themes were summarized in tabular format. CONCLUSIONS The reported indications for CBCT use in implant dentistry vary from preoperative analysis regarding specific anatomic considerations, site development using grafts, and computer-assisted treatment planning to postoperative evaluation focusing on complications due to damage of neurovascular structures. Effective doses for different CBCT devices exhibit a wide range with the lowest dose being almost 100 times less than the highest dose. Significant dose reduction can be achieved by adjusting operating parameters, including exposure factors and reducing the field of view (FOV) to the actual region of interest.

Symptom-based subtypes of depression and their psychosocial correlates: A person-centered approach focusing on the influence of sex

BACKGROUND: Reducing the complexity of major depressive disorder by symptom-based subtypes constitutes the basis of more specific treatments. To date, few studies have empirically derived symptom subtypes separated by sex, although the impact of sex has been widely accepted in depression research. METHODS: The community-based sample included 373 males and 443 females from the Zurich Program for Sustainable Development of Mental Health Services (ZInEP) manifesting depressive symptoms in the past 12 months. Latent Class Analysis (LCA) was performed separately by sex to extract sex-related depression subtypes. The subtypes were characterized by psychosocial characteristics. RESULTS: Three similar subtypes were found in both sexes: a severe typical subtype (males: 22.8%; females: 35.7%), a severe atypical subtype (males: 17.4%; females: 22.6%), and a moderate subtype (males: 25.2%; females: 41.8%). In males, two additional subgroups were identified: a severe irritable/angry-rejection sensitive (IARS) subtype (30%) comprising the largest group, and a small psychomotor retarded subtype (4%). Males belonging to the severe typical subtype exhibited the lowest masculine gender role orientation, while females of the typical subtype showed more anxiety disorders. The severe atypical subtype was associated with eating disorders in both sexes and with alcohol/drug abuse/dependence in females. In contrast, alcohol/drug abuse/dependence was associated with the severe IARS subtype in males. LIMITATIONS:The study had a cross-sectional design, allowing for no causal inferences. CONCLUSIONS:This study contributes to a better understanding of sex-related depression subtypes, which can be well distinguished on the basis of symptom profiles. This provides the base for future research investigating the etiopathogenesis and effective treatment of the heterogeneous depression disorder.

Retrospective evaluation of all recorded horse race starts in Switzerland during a four-year period focusing on discipline specific risk factors for clinical events

REASONS FOR PERFORMING THE STUDY: Racetrack injuries are of welfare concern and prevention of injuries is an important goal in many racing jurisdictions. Over the years this has led to more detailed recording of clinical events on racecourses. However, risk factor analyses of clinical events at race meetings have never been reported for Switzerland OBJECTIVE: To identify discipline-specific factors that influence the occurrence of clinical events during race meetings with the ultimate aim to improve the monitoring and safety on racetracks in Switzerland and optimise racehorse welfare. STUDY DESIGN: Retrospective study of horse race data collected by the Swiss horse racing association. METHODS: All race starts (n = 17,670, including 6,198 flat, 1,257 obstacle and 10,215 trot race starts) recorded over a period of four years (2009-2012) were analysed in multivariable mixed effect logistic regression models including horse and racecourse related data. The models were designed to identify discipline specific factors influencing the occurrence of clinical events on racecourses in Switzerland. RESULTS: Factors influencing the risk of clinical events during races were different for each discipline. The risk of a clinical event in trot racing was lower for racing on a Porphyre-sand track than on grass tracks. Horses whose driver was also their trainer had an approximately two times higher risk for clinical events. In obstacle races, longer distances (2401-3300 m and 3301-5400 m respectively) had a protective effect compared to racing over shorter distances. In flat racing, five racecourses reported significantly less clinical events. In all three disciplines, finishing 8th place or later was associated with clinical events. CONCLUSIONS: Changes in management that aim to improve the safety and welfare of racehorses, such as racetrack adaptations, need to be individualised for each discipline.

Sensitivity and fragmentation calibration of the ROSINA double focusing mass spectrometer

The goal of this work has been to calibrate sensitivities and fragmentation pattern of various molecules as well as further characterize the lab model of the ROSINA Double Focusing Mass Spectrometer (DFMS) on board ESA’s Rosetta spacecraft bound to comet 67P/Churyumov-Gerasimenko. The detailed calibration and characterization of the instrument is key to understand and interpret the results in the coma of the comet. A static calibration was performed for the following species: Ne, Ar, Kr, Xe, H2O, N2, CO2, CH4, C2H6, C3H8, C4H10, and C2H4. The purpose of the calibration was to obtain sensitivities for all detectors and emissions, the fragmentation behavior of the ion source and to show the capabilities to measure isotopic ratios at the comet. The calibration included the recording of different correction factors to evaluate the data, including a detailed investigation of the detector gain. The quality of the calibration that could be tested for different gas mixtures including the calibration of the density inside the ion source when calibration gas from the gas calibration unit is introduced. In conclusion the calibration shows that DFMS meets the design requirements and that DFMS will be able to measure the D/H at the comet and help shed more light on the puzzle about the origin of water on Earth.

Computer simulations of sample preconcentration in carrier-free systems and isoelectric focusing in microchannels using simple ampholytes.

In this work, electrophoretic preconcentration of protein and peptide samples in microchannels was studied theoretically using the 1D dynamic simulator GENTRANS, and experimentally combined with MS. In all configurations studied, the sample was uniformly distributed throughout the channel before power application, and driving electrodes were used as microchannel ends. In the first part, previously obtained experimental results from carrier-free systems are compared to simulation results, and the effects of atmospheric carbon dioxide and impurities in the sample solution are examined. Simulation provided insight into the dynamics of the transport of all components under the applied electric field and revealed the formation of a pure water zone in the channel center. In the second part, the use of an IEF procedure with simple well defined amphoteric carrier components, i.e. amino acids, for concentration and fractionation of peptides was investigated. By performing simulations a qualitative description of the analyte behavior in this system was obtained. Neurotensin and [Glu1]-Fibrinopeptide B were separated by IEF in microchannels featuring a liquid lid for simple sample handling and placement of the driving electrodes. Component distributions in the channel were detected using MALDI- and nano-ESI-MS and data were in agreement with those obtained by simulation. Dynamic simulations are demonstrated to represent an effective tool to investigate the electrophoretic behavior of all components in the microchannel.