The taper corrosion pattern observed for one bi-modular stem design is related to geometry-determined taper mechanics

Bi-modular primary hip stems exhibit high revision rates owing to corrosion at the stem-neck taper, and are associated with local adverse tissue reactions. The aim of this study was to relate the wear patterns observed for one bi-modular design to its design-specific stem-neck taper geometry. Wear patterns and initial geometry of the taper junctions were determined for 27 retrieved bi-modular primary hip arthroplasty stems (Rejuvenate, Stryker Orthopaedics) using a tactile coordinate-measuring device. Regions of high-gradient wear patterns were additionally analyzed via optical and electron microscopy. The determined geometry of the taper junction revealed design-related engagement at its opening (angle mismatch), concentrated at the medial and lateral apexes (axes mismatch). A patch of retained topography on the proximal medial neck-piece taper apex was observed, surrounded by regions of high wear. On the patch, a deposit from the opposing female stem taper—containing Ti, Mo, Zr, and O—was observed. High stress concentrations were focused at the taper apexes owing to the specific geometry. A medial canting of the components may have augmented the inhomogeneous stress distributions in vivo. In the regions with high normal loads interfacial slip and consequently fretting was inhibited, which explains the observed pattern of wear

Fashioning Entitlements: A Comparative Law and Economic Analysis of the Judicial Role in Environmental Centralization in the U.S. and Europe

This paper identifies and evaluates, from an economic point of view, the role of the judiciary the steady shift of environmental regulatory authority to higher, more centralized levels of government in both the U.S. and Europe. We supply both a positive analysis of how the decisions made by judges have affected the incentives of both private and public actors to pollute the natural environment, and normative answers to the question of whether judges have acted so as to create incentives that move levels of pollution in an efficient direction, toward their optimal, cost-minimizing (or net-benefit-maximizing) levels. Highlights of the analysis include the following points: 1) Industrial-era local (state or national) legislation awarding entitlements to pollute was almost certainly inefficient due to a fundamental economic obstacle faced by those who suffer harm from the over-pollution of publicly owned natural resources: the inability to monetize and credibly commit to repay the future economic value of reducing pollution. 2) When industrial era pollution spilled across state lines in the US, the federal courts, in particular the Supreme Court, fashioned a federal common law of interstate nuisance that set up essentially the same sort of blurry, uncertain entitlements to pollute or be free of pollution that had been created by the state courts in resolving local pollution disputes. We argue that for the typical pollution problem, a legal regime of blurry interstate entitlements - with neither jurisdiction having a clear right either to pollute or be free of pollution from the other - is likely to generate efficient incentives for interjursidictional bargaining, even despite the public choice problems besetting majority-rule government. Interestingly, a very similar system of de facto entitlements arose and often stimulated interjursidictional bargaining in Europe as well as in the U.S. 3) The US federal courts have generally interpreted the federal environmental statutes in ways that give clear primacy to federal regulators. Through such judicial interpretation, state and local regulators face a continuing risk of having their decisions overridden by federal regulators. This reduces the incentives for regulatory innovation at the state and local level. Judicial authorization of federal overrides has thus weakened the economic rationale for cooperative federalism suggested by economic models of principal-agent relationships. As a result of the principle of attribution, there is less risk in Europe that (like in the US) courts would enlarge the federal purview and thereby limit the powers of the Member States. Despite this principle, the power of the European bureaucracy (that is, the European Commission) has steadily increased and led to a steady shift of environmental regulatory competencies to the European level. This shift is only sometimes normatively desirable, and yet there is little that the ECJ can or will do to slow it

Diagnostic guidelines for the histological particle algorithm in the periprosthetic neo-synovial tissue

Background The identification of implant wear particles and non-implant related particles and the characterization of the inflammatory responses in the periprosthetic neo-synovial membrane, bone, and the synovial-like interface membrane (SLIM) play an important role for the evaluation of clinical outcome, correlation with radiological and implant retrieval studies, and understanding of the biological pathways contributing to implant failures in joint arthroplasty. The purpose of this study is to present a comprehensive histological particle algorithm (HPA) as a practical guide to particle identification at routine light microscopy examination. Methods The cases used for particle analysis were selected retrospectively from the archives of two institutions and were representative of the implant wear and non-implant related particle spectrum. All particle categories were described according to their size, shape, colour and properties observed at light microscopy, under polarized light, and after histochemical stains when necessary. A unified range of particle size, defined as a measure of length only, is proposed for the wear particles with five classes for polyethylene (PE) particles and four classes for conventional and corrosion metallic particles and ceramic particles. Results All implant wear and non-implant related particles were described and illustrated in detail by category. A particle scoring system for the periprosthetic tissue/SLIM is proposed as follows: 1) Wear particle identification at light microscopy with a two-step analysis at low (× 25, × 40, and × 100) and high magnification (× 200 and × 400); 2) Identification of the predominant wear particle type with size determination; 3) The presence of non-implant related endogenous and/or foreign particles. A guide for a comprehensive pathology report is also provided with sections for macroscopic and microscopic description, and diagnosis. Conclusions The HPA should be considered a standard for the histological analysis of periprosthetic neo-synovial membrane, bone, and SLIM. It provides a basic, standardized tool for the identification of implant wear and non-implant related particles at routine light microscopy examination and aims at reducing intra-observer and inter-observer variability to provide a common platform for multicentric implant retrieval/radiological/histological studies and valuable data for the risk assessment of implant performance for regional and national implant registries and government agencies

Untersuchungen an Tension-Leg-Plattformen fuer die Nordsee

AppendixTIB Hannover: FR 3545+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Effect of an Educational Intervention on Medical Student Scripting and Patient Satisfaction: A Randomized Trial

Introduction: Effective communication between clinicians and patients has been shown to improve patient outcomes, reduce malpractice liability, and is now being tied to reimbursement. Use of a communication strategy known as “scripting” has been suggested to improve patient satisfaction in multiple hospital settings, but the frequency with which medical students use this strategy and whether this affects patient perception of medical student care is unknown. Our objective was to measure the use of targeted communication skills after an educational intervention as well as to further clarify the relationship between communication element usage and patient satisfaction. Methods: Medical students were block randomized into the control or intervention group. Those in the intervention group received refresher training in scripted communication. Those in the control group received no instruction or other intervention related to communication. Use of six explicit communication behaviors were recorded by trained study observers: 1) acknowledging the patient by name, 2) introducing themselves as medical students, 3) explaining their role in the patient’s care, 4) explaining the care plan, 5) providing an estimated duration of time to be spent in the emergency department (ED), and 6) notifying the patient that another provider would also be seeing them. Patients then completed a survey regarding their satisfaction with the medical student encounter. Results: We observed 474 medical student-patient encounters in the ED (231 in the control group and 243 in the intervention group). We were unable to detect a statistically significant difference in communication element use between the intervention and control groups. One of the communication elements, explaining steps in the care plan, was positively associated with patient perception of the medical student’s overall communication skills. Otherwise, there was no statistically significant association between element use and patient satisfaction. Conclusion: We were unable to demonstrate any improvement in student use of communication elements or in patient satisfaction after refresher training in scripted communication. Furthermore, there was little variation in patient satisfaction based on the use of scripted communication elements. Effective communication with patients in the ED is complicated and requires further investigation on how to provide this skill set

Entwicklung eines Schwerlasthebe- und Transportsystems fuer die Installation von Offshore-Foerderplattformen

Appendix A: Rough-sea testing of a heavy lift and transport barge (HSVA-S--23 6/87). Appendix B: Theoretical investigations of the sea-state capability of the 'U-Barge' heavy lift and transport systemTIB Hannover: FR 2534+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman