Measurements of ultrasound from public address and voice alarm systems in public places.

Concerns have been raised about potential health effects of public exposure to ultrasound; however, there are few published surveys of measurements taken in public places. Results are presented of measurements taken in a selection of public places including train stations, shopping centres, galleries and museums, and the difficulties of taking measurements with conventional equipment are highlighted. Tones were identified in the 20 kHz third-octave band at 8 of the 14 locations tested; the characteristics of the tones are consistent with their source being Public Address or Voice Alarm systems. The measured results do not exceed existing interim guidelines for public exposure to ultrasound, and existing research suggests that no significant undesirable effects would be anticipated following exposure to ultrasound of this nature for short periods. The measured data may be reviewed against future public exposure guidelines which consider the variation in response across the population and between continuous and pulsed sources.

Contractility as a global regulator of cellular morphology, velocity, and directionality in low-adhesive fibrillary micro-environments.

Recent reports demonstrated that migration in fibrillary environments can be mimicked by spatial confinement achieved with micro-patterning [1]. Here we investigated whether a model system based on linearly structured surfaces allows to draw conclusions about migration of endothelial cells (ECs) in fibrillary 3D environments. We found that ECs on 3 µm wide tracks (termed as 1D) migrate less efficient in comparison to ECs on broader tracks in regard to velocity and directional persistence. The frequent changes of direction in ECs on narrow tracks are accompanied by pronounced cell rounding and membrane blebbing, while cells migrating with an elongated morphology display a single lamellipodium. This behavior is contractility-dependent as both modes can be provoked by manipulating activity of myosin II (blebbistatin or calyculin A, respectively). The comparison between 1D and 3D migrating cells revealed a striking similarity in actin architecture and in switching between two morphologies. ECs move more directed but slower upon inhibition of contractility in 1D and 3D, in contrast to 2D cell culture. We conclude that micro-patterning can be used to study morphological switches in a controlled manner with a prognostic value for 3D environments. Moreover, we identified blebbing as a new aspect of EC migration.

Remote display performance for wireless healthcare computing.

Organizations are beginning to recognize that health care providers are highly mobile and optimal care requires providing access to a large and dynamic body of information wherever the provider and patient are. Remote display protocols (RDP) are one way that organizations are using to deliver healthcare applications to mobile users. While many organizations have begun to use RDPs to deliver real-time access to health care information to clinicians, little formal work has been done to evaluate the performance or the effectiveness of thin-client computing with health care applications. This study examines the performance of wireless thin-client tablets with two web-based clinical applications, a text-centric, graphics-poor EMR and a graphic-rich image analysis program. The study compares the performance of two popular RDP implementations, Citrix and Microsoft Remote Desktop, with the performance of a traditional web browser in a wireless environment. For both applications, the RDPs demonstrated both higher speed and reduced bandwidth requirements than the web browser.

Cell motility on polyethylene glycol block copolymers correlates to fibronectin surface adsorption.

Adhesion and motility of cells on polyethylene glycol (PEG) engineered surfaces are of fundamental interest for the development of biotechnological devices. Here, the structure of PEG block copolymers physisorbed to surfaces by polyLlysine (PLL) or polypropylene oxide (PPO) is studied. Cell behavior on such surfaces incubated with fibronectin (FN) is analyzed via time-lapse microscopy, the amount and the location of FN is determined via neutron reflectivity. While FN does not adsorb onto PPOPEG, 0.4-0.7 mg m(-2) of FN is found in the vicinity of the PLL moiety of PLLPEG. Cells exhibit 21% increased motility on PLLPEG (5 kDa PEG chains) compared to pure FN layers, and 12% decreased motility for PLLPEG (2 kDa PEG chains). These findings suggest that by design of PEGylated surfaces cell migration can be controlled.