Design and operation of ARGONTUBE: a 5 m long drift liquid argon TPC

The Liquid Argon Time Projection Chamber (LArTPC) is a prime type of detector for future large-mass neutrino observatories and proton decay searches. In this paper we present the design and operation, as well as experimental results from ARGONTUBE, a LArTPC being operated at the AEC-LHEP, University of Bern. The main goal of this detector is to prove the feasibility of charge drift over very long distances in liquid argon. Many other aspects of the LArTPC technology are also investigated, such as a voltage multiplier to generate high voltage in liquid argon (Greinacher circuit), a cryogenic purification system and the application of multi-photon ionization of liquid argon by a UV laser. For the first time, tracks induced by cosmic muons and UVlaser beam pulses have been observed and studied at drift distances of up to 5 m, the longest reached to date.

Design and Realization of an Energy Harvester Using Pulsating Arterial Pressure

Most medical implants run on batteries, which require costly and tedious replacement or recharging. It is believed that micro-generators utilizing intracorporeal energy could solve these problems. However, such generators do not, at this time, meet the energy requirements of medical implants.This paper highlights some essential aspects of designing and implementing a power source that scavenges energy from arterial expansion and contraction to operate an implanted medical device. After evaluating various potentially viable transduction mechanisms, the fabricated prototype employs an electromagnetic transduction mechanism. The artery is inserted into a laboratory-fabricated flexible coil which is permitted to freely deform in a magnetic field. This work also investigates the effects of the arterial wall's material properties on energy harvesting potential. For that purpose, two types of arteries (Penrose X-ray tube, which behave elastically, and an artery of a Göttinger minipig, which behaves viscoelastically) were tested. No noticeable difference could be observed between these two cases. For the pig artery, average harvestable power was 42 nW. Moreover, peak power was 2.38 μW. Both values are higher than those of the current state of the art (6 nW/16 nW). A theoretical modelling of the prototype was developed and compared to the experimental results.

Design and Test of a 0.5 THz Dipole Antenna With Integrated Schottky Diode Detector on a High Dielectric Constant Ceramic Electromagnetic Bandgap Substrate

This paper presents the first analysis of the input impedance and radiation properties of a dipole antenna, placed on top of Fan 's three-dimensional electromagnetic bandgap (EBG) structure, (Applied Physics Letters, 1994) constructed using a high dielectric constant ceramic. The best position of the dipole on the EBG surface is determined following impedance and radiation pattern analyses. Based on this optimum configuration an integrated Schottky heterodyne detector was designed, manufactured and tested from 0.48 to 0.52 THz. The main antenna features were not degraded by the high dielectric constant substrate due to the use of the EBG approach. Measured radiation patterns are in good agreement with the predicted ones.

Precision of fit and retention force of cast non-precious-crowns on standard titanium implant-abutment with different design and height

OBJECTIVE The cost-effectiveness of cast nonprecious frameworks has increased their prevalence in cemented implant crowns. The purpose of this study was to assess the effect of the design and height of the retentive component of a standard titanium implant abutment on the fit, possible horizontal rotation and retention forces of cast nonprecious alloy crowns prior to cementation. MATERIALS AND METHODS Two abutment designs were examined: Type A with a 6° taper and 8 antirotation planes (Straumann Tissue-Level RN) and Type B with a 7.5° taper and 1 antirotation plane (SICace implant). Both types were analyzed using 60 crowns: 20 with a full abutment height (6 mm), 20 with a medium abutment height (4 mm), and 20 with a minimal (2.5 mm) abutment height. The marginal and internal fit and the degree of possible rotation were evaluated by using polyvinylsiloxane impressions under a light microscope (magnification of ×50). To measure the retention force, a custom force-measuring device was employed. STATISTICAL ANALYSIS one-sided Wilcoxon rank-sum tests with Bonferroni-Holm corrections, Fisher's exact tests, and Spearman's rank correlation coefficient. RESULTS Type A exhibited increased marginal gaps (primary end-point: 55 ± 20 μm vs. 138 ± 59 μm, P < 0.001) but less rotation (P < 0.001) than Type B. The internal fit was also better for Type A than for Type B (P < 0.001). The retention force of Type A (2.49 ± 3.2 N) was higher (P = 0.019) than that of Type B (1.27 ± 0.84 N). Reduction in abutment height did not affect the variables observed. CONCLUSION Less-tapered abutments with more antirotation planes provide an increase in the retention force, which confines the horizontal rotation but widens the marginal gaps of the crowns. Thus, casting of nonprecious crowns with Type A abutments may result in clinically unfavorable marginal gaps.

Fluorescence-encoded gold nanoparticles: library design and modulation of cellular uptake into dendritic cells.

In order to harness the unique properties of nanoparticles for novel clinical applications and to modulate their uptake into specific immune cells we designed a new library of homo- and hetero-functional fluorescence-encoded gold nanoparticles (Au-NPs) using different poly(vinyl alcohol) and poly(ethylene glycol)-based polymers for particle coating and stabilization. The encoded particles were fully characterized by UV-Vis and fluorescence spectroscopy, zeta potential and dynamic light scattering. The uptake by human monocyte derived dendritic cells in vitro was studied by confocal laser scanning microscopy and quantified by fluorescence-activated cell sorting and inductively coupled plasma atomic emission spectroscopy. We show how the chemical modification of particle surfaces, for instance by attaching fluorescent dyes, can conceal fundamental particle properties and modulate cellular uptake. In order to mask the influence of fluorescent dyes on cellular uptake while still exploiting its fluorescence for detection, we have created hetero-functionalized Au-NPs, which again show typical particle dependent cellular interactions. Our study clearly prove that the thorough characterization of nanoparticles at each modification step in the engineering process is absolutely essential and that it can be necessary to make substantial adjustments of the particles in order to obtain reliable cellular uptake data, which truly reflects particle properties.

The ARCH Projects: design and rationale (IAASSG 001).

OBJECTIVE A number of factors limit the effectiveness of current aortic arch studies in assessing optimal neuroprotection strategies, including insufficient patient numbers, heterogenous definitions of clinical variables, multiple technical strategies, inadequate reporting of surgical outcomes and a lack of collaborative effort. We have formed an international coalition of centres to provide more robust investigations into this topic. METHODS High-volume aortic arch centres were identified from the literature and contacted for recruitment. A Research Steering Committee of expert arch surgeons was convened to oversee the direction of the research. RESULTS The International Aortic Arch Surgery Study Group has been formed by 41 arch surgeons from 10 countries to better evaluate patient outcomes after aortic arch surgery. Several projects, including the establishment of a multi-institutional retrospective database, randomized controlled trials and a prospectively collected database, are currently underway. CONCLUSIONS Such a collaborative effort will herald a turning point in the surgical management of aortic arch pathologies and will provide better powered analyses to assess the impact of varying surgical techniques on mortality and morbidity, identify predictors for neurological and operative risk, formulate and validate risk predictor models and review long-term survival outcomes and quality-of-life after arch surgery.

German Total Ankle Replacement Register of the German Foot and Ankle Society (D. A. F.) - presentation of design and reliability of the data as well as first results

INTRODUCTION Even though arthroplasty of the ankle joint is considered to be an established procedure, only about 1,300 endoprostheses are implanted in Germany annually. Arthrodeses of the ankle joint are performed almost three times more often. This may be due to the availability of the procedure - more than twice as many providers perform arthrodesis - as well as the postulated high frequency of revision procedures of arthroplasties in the literature. In those publications, however, there is often no clear differentiation between revision surgery with exchange of components, subsequent interventions due to complications and subsequent surgery not associated with complications. The German Orthopaedic Foot and Ankle Association's (D. A. F.) registry for total ankle replacement collects data pertaining to perioperative complications as well as cause, nature and extent of the subsequent interventions, and postoperative patient satisfaction. MATERIAL AND METHODS The D. A. F.'s total ankle replacement register is a nation-wide, voluntary registry. After giving written informed consent, the patients can be added to the database by participating providers. Data are collected during hospital stay for surgical treatment, during routine follow-up inspections and in the context of revision surgery. The information can be submitted in paper-based or online formats. The survey instruments are available as minimum data sets or scientific questionnaires which include patient-reported outcome measures (PROMs). The pseudonymous clinical data are collected and evaluated at the Institute for Evaluative Research in Medicine, University of Bern/Switzerland (IEFM). The patient-related data remain on the register's module server in North Rhine-Westphalia, Germany. The registry's methodology as well as the results of the revisions and patient satisfaction for 115 patients with a two year follow-up period are presented. Statistical analyses are performed with SAS™ (Version 9.4, SAS Institute, Inc., Cary, NC, USA). RESULTS About 2½ years after the register was launched there are 621 datasets on primary implantations, 1,427 on follow-ups and 121 records on re-operation available. 49 % of the patients received their implants due to post-traumatic osteoarthritis, 27 % because of a primary osteoarthritis and 15 % of patients suffered from a rheumatic disease. More than 90 % of the primary interventions proceeded without complications. Subsequent interventions were recorded for 84 patients, which corresponds to a rate of 13.5 % with respect to the primary implantations. It should be noted that these secondary procedures also include two-stage procedures not due to a complication. "True revisions" are interventions with exchange of components due to mechanical complications and/or infection and were present in 7.6 % of patients. 415 of the patients commented on their satisfaction with the operative result during the last follow-up: 89.9 % of patients evaluate their outcome as excellent or good, 9.4 % as moderate and only 0.7 % (3 patients) as poor. In these three cases a component loosening or symptomatic USG osteoarthritis was present. Two-year follow-up data using the American Orthopedic Foot and Ankle Society Ankle and Hindfoot Scale (AOFAS-AHS) are already available for 115 patients. The median AOFAS-AHS score increased from 33 points preoperatively to more than 80 points three to six months postoperatively. This increase remained nearly constant over the entire two-year follow-up period. CONCLUSION Covering less than 10 % of the approximately 240 providers in Germany and approximately 12 % of the annually implanted total ankle-replacements, the D. A. F.-register is still far from being seen as a national registry. Nevertheless, geographical coverage and inclusion of "high-" (more than 100 total ankle replacements a year) and "low-volume surgeons" (less than 5 total ankle replacements a year) make the register representative for Germany. The registry data show that the number of subsequent interventions and in particular the "true revision" procedures are markedly lower than the 20 % often postulated in the literature. In addition, a high level of patient satisfaction over the short and medium term is recorded. From the perspective of the authors, these results indicate that total ankle arthroplasty - given a correct indication and appropriate selection of patients - is not inferior to an ankle arthrodesis concerning patients' satisfaction and function. First valid survival rates can be expected about 10 years after the register's start.

Refinement of experimental design and conduct in laboratory animal research.

The scientific literature of laboratory animal research is replete with papers reporting poor reproducibility of results as well as failure to translate results to clinical trials in humans. This may stem in part from poor experimental design and conduct of animal experiments. Despite widespread recognition of these problems and implementation of guidelines to attenuate them, a review of the literature suggests that experimental design and conduct of laboratory animal research are still in need of refinement. This paper will review and discuss possible sources of biases, highlight advantages and limitations of strategies proposed to alleviate them, and provide a conceptual framework for improving the reproducibility of laboratory animal research.