PURPOSE We aimed to investigate effects of instrument settings on porcine vitreous flow rates through dual pneumatic high-speed vitrectomy probes. METHODS The CONSTELLATION(®) Vision System was tested with 250, 450, and 650 mmHg of vacuum using six ULTRAVIT(®) vitrectomy probes of each diameter (25+(®), 25, 23, and 20 gauge) operated from 500 cuts per minute (cpm) up to 5,000 cpm. Duty cycle ...

OBJECTIVES To determine the effect of graft placement and orientation on flow rates through a partially obstructed coronary artery. METHODS A numerical, parametric study of blood flow in the human coronary artery was conducted using computational fluid dynamics simulation. A cylindrical approximation of the coronary artery with varying degrees of stenosis, with and without a bypass graft, was...

OBJECTIVE To investigate the effects of height, external pressure, and bladder fullness on the flow rate in continuous, non-continuous cystoscopy and the automated irrigation fluid pumping system (AIFPS). MATERIALS Each experiment had two 2-litre 0.9% saline bags connected to a continuous, non-continuous cystoscope or AIFPS via irrigation tubing. Other equipment included height-adjustable dri...

In this study, a white light particle image velocimetry (WL PIV) system which employs a light sheet generated with a flash was used. The system was developed in order to provide a cost-efficient and safe alternative to laser systems while keeping the accuracy limits required for hydraulic model tests. To investigate the accuracy of WL PIV method under different flow conditions, experiments were...

AIM To compare the flow rates of readily available intravenous infusion devices and to compare the effect of the addition of pressure or a needle-free intravenous connector device. METHODS Several intravenous devices with different characteristics had their flow rates determined under a standard set of conditions. The flow rates were then measured with the addition of a pressure bag to the sy...

In some case of laboratory and industrial applications, various kind of measurement instruments must be placed in a conduit, in which multiphase fluid flows. Vortex shedding for any immersed body in flow field is created with a frequency, which according to flow conditions such as flow rates, geometry of body, etc. may be constant or variable. Failure may happen, if this frequency is close to o...

We present a microfluidic device for culturing adherent cells over a logarithmic range of flow rates. The device sets flow rates through four separate cell-culture chambers using syringe-driven flow and a network of fluidic resistances. The design is easy to fabricate with no on-chip valves and is scalable both in the number of culture chambers as well as in the range of applied flow rates. Usi...

I consider two issues concerning how to monitor global poverty for the Millennium Development Goals, the selection of poverty lines, and the data sources for monitoring poverty over time. I discuss the choice of a single international line, converted using purchasing power parity (PPP) exchange rates, versus the use of country-specific poverty lines. I note the difficulties in constructing PPP ...

During the design of ABR tra c management at the ATM Forum, we performed several analyses to ensure that the ABR service will operate e ciently over satellite links. In the cases where the performance was unacceptable, we suggested modi cations to the tra c management speci cations. This paper describes one such issue related to the count of missing resource management cells (Crm) parameter of ...

We tested whether the reduction of metabolic rate (MR) in hibernating Cercartetus nanus (Marsupialia, 36 g) is better explained by the reduction of body temperature (Tb), the differential (ΔT) between Tb and air temperature (Ta), or thermal conductance (C). Above the critical Ta during torpor (Ttc) of 4.8 ± 0.7°C, where the Tb was not regulated, the steady-state MR was an exponential function o...