Ultrasound-induced Gas Release from Contrast Agent Microbubbles

We investigated gas release from two hard-shelled ultrasound contrast agents by subjecting them to high-mechanical index (MI) ultrasound and simultaneously capturing high-speed photographs. At an insonifying frequency of 1.7 MHz, a larger percentage of contrast bubbles is seen to crack than at 0.5 MHz. Most of the released gas bubbles have equilibrium diameters between 1.25 and 1.75 /spl mu/m. Their disappearance was observed optically. Free gas bubbles have equilibrium diameters smaller than the bubbles from which they have been released. Coalescence may account for the long dissolution times acoustically observed and published in previous studies. After sonic cracking, the cracked bubbles stay acoustically active

Ultrasonic motion analysis system - measurement of temporal and spatial gait parameters

The duration of stance and swing phase and step and stride length are important parameters in human gait. In this technical note a low-cost ultrasonic motion analysis system is described that is capable of measuring these temporal and spatial parameters while subjects walk on the floor. By using the propagation delay of sound when transmitted in air, this system is able to record the position of the subjects' feet. A small ultrasonic receiver is attached to both shoes of the subject while a transmitter is placed stationary on the floor. Four healthy subjects were used to test the device. Subtracting positions of the foot with zero velocity yielded step and stride length. The duration of stance and swing phase was calculated from heel-strike and toe-off. Comparison with data obtained from foot contact switches showed that applying two relative thresholds to the speed graph of the foot could reliably generate heel-strike and toe-off. Although the device is tested on healthy subjects in this study, it promises to be extremely valuable in examining pathological gait. When gait is asymmetrical, walking speed is not constant or when patients do not completely lift their feet, most existing devices will fail to correctly assess the proper gait parameters. Our device does not have this shortcoming and it will accurately demonstrate asymmetries and variations in the patient's gait. As an example, the recording of a left hemiplegic patient is presented in the discussion. (C) 2002 Elsevier Science Ltd. All rights reserved

Custom, Normative Practice, and the Law

Legally binding custom is conventionally analyzed in terms of two independent elements: regularities of behavior (usus) and convictions of actors engaging in the behavior that it is legally required (opinio juris). This additive conception of custom is deeply flawed. This Essay argues that we must abandon the additive conception and replace it with an account of custom that understands legally relevant customs as norms that arise from discursive normative practices embedded in rich contexts of social interaction characterized by intermeshing anticipations and interconnected conduct. The hallmark of legally binding customs, it is argued, is not the addition of belief or conviction to behavior, but rather the integration of meaningful conduct into a web of legally recognized reasons and arguments

Custom, Normative Practice, and the Law

Legally binding custom is conventionally analyzed in terms of two independent elements: regularities of behavior (usus) and convictions of actors engaging in the behavior that it is legally required (opinio juris). This additive conception of custom is deeply flawed. This Essay argues that we must abandon the additive conception and replace it with an account of custom that understands legally relevant customs as norms that arise from discursive normative practices embedded in rich contexts of social interaction characterized by intermeshing anticipations and interconnected conduct. The hallmark of legally binding customs, it is argued, is not the addition of belief or conviction to behavior, but rather the integration of meaningful conduct into a web of legally recognized reasons and arguments

From satisfaction to expectation: The patient's perspective in lower limb prosthetic care

Neck pain is a common musculoskeletal complaint and a relationship with reduced work-related functional capacity is assumed. A validated instrument to test functional capacity of patients with neck pain is unavailable. The objective of this study was to develop a Functional Capacity Evaluation (FCE), which is content valid for determining functional capacity in patients with work related neck disorders (WRND). A review of epidemiological review literature was conducted to identify physical risk factors for WRND. Evidence was found that physical risk factors contribute in development of WRND. Physical risk factors were related to repetitive movements, forceful movements, awkward positions and static contractions of the neck or the neck/shoulder region. An FCE was designed based on the risk factors identified. Eight tests were selected to cover all risk factors: repetitive side reaching, repetitive reaching overhead, static overhead work, front carry, forward static bend neck, overhead lift and the neck strength test. Content validity of this FCE was established by providing the rationale, specific objectives and operational definitions of the FCE. Further research is needed to establish reliability and other aspects of validity of the neck-FCE Aim Worldwide, family- centred and co- ordinated care are seen as the two most desirable and effective methods of paediatric care delivery. This study outlines current views on how team collaboration comprising professionals in paediatric rehabilitation and special education and the parents of children with disabilities should be organized, and analyses the policies of five paediatric rehabilitation settings associated with the care of 44 children with cerebral palsy ( CP) in the Netherlands. Methods For an overview of current ideas on collaboration, written statements of professional associations in Dutch paediatric rehabilitation were examined. The policy statements of the five participating settings were derived from their institutional files. Documents detailing the collaborative arrangements involving the various professionals and parents were evaluated at the institutional level and at the child level. Involvement of the stakeholders was analysed based on team conferences. Results Also in the Netherlands collaboration between rehabilitation and education professionals and parents is endorsed as the key principle in paediatric rehabilitation, with at its core the team conference in which the various priorities and goals are formulated and integrated into a personalized treatment plan. As to their collaborative approaches between rehabilitation centre and school, the five paediatric settings rarely differed, but at the child level approaches varied. Teams were large ( averaging 10.5 members), and all three stakeholder groups were represented, but involvement differed per setting, as did the roles and contributions of the individual team members. Conclusion Collaboration between rehabilitation and education professionals and parents is supported and encouraged nationwide. Views on collaboration have been formulated, and general guidelines on family- centred and co- ordinated care are available. Yet, collaborative practices in Dutch paediatric care are still developing. Protocols that carefully delineate the commitments to collaborate and that translate the policies into practical, detailed guidelines are needed, as they are a prerequisite for successful teamwork

Use and usability of custom-made orthopedic shoes

The goal of this study was to investigate the use of custom-made orthopedic shoes (OS) and the association between the use of OS and the most relevant aspects of their usability. Over a 6-month period, patients meeting the inclusion criteria were recruited by 12 orthopedic shoe companies scattered throughout the Netherlands and asked to complete a questionnaire composed of a pre- and post-OS section. Patients with different pathologies were included in the study (n = 339; response 67%). Mean age of the patients was 63 +/- 15 years, and 38% were male. Three months after delivery, 81% of the patients used their OS frequently (4-7 days/week), 13% occasionally (1-3 days/week), and 6% did not use their OS. Associations were found between use and all measured aspects of usability (p-values varied from <0.001 to 0.028). Patients who used their OS more often had a more positive opinion regarding all the aspects of usability. We conclude that all aspects of the usability of OS are relevant in relation to their use and should be taken into account when prescribing and evaluating OS