480 research outputs found
Issues in Mobile E-Commerce
Though many companies are still just beginning to grasp the potential uses and impacts of the Web and e-commerce, advances in technologies and their application continue. These advances often present various managerial and technological issues for individuals, companies, governments, and other entities. One significant area of technological advancement is the development of mobile e-commerce, which encompasses interactive business activities and processes related to a (potential) commercial transaction conducted through communications networks that interface with wireless devices. These systems provide the potential for organizations and users to perform various commerce-related tasks without regard to time and location (anytime from anywhere). This emerging mobile e-commerce environment presents a new set of issues. This paper identifies and categorizes some of these issues so that researchers, developers, and managers have a starting point for focusing their activities within the emerging m-commerce domain. Our examination finds categories that include technological (both client and infrastructure) issues, application issues, and areas for future research
Multi-scale Optics for Enhanced Light Collection from a Point Source
High efficiency collection of photons emitted by a point source over a wide
field-of-view (FoV) is crucial for many applications. Multi-scale optics over
improved light collection by utilizing small optical components placed close to
the optical source, while maintaining a wide FoV provided by conventional
imaging optics. In this work, we demonstrate collection efficiency of 26% of
photons emitted by a point-like source using a micromirror fabricated in
silicon with no significant decrease in collection efficiency over a 10 mm
object space.Comment: 4 pages, 4 figure
Deriving a Provisional Tolerable Intake for Intravenous Exposure to Silver Nanoparticles Released from Medical Devices
Silver nanoparticles (AgNP) are incorporated into medical devices for their anti-microbial characteristics. The potential exposure and toxicity of AgNPs is unknown due to varying physicochemical particle properties and lack of toxicological data. The aim of this safety assessment is to derive a provisional tolerable intake (pTI) value for AgNPs released from blood-contacting medical devices. A literature review of in vivo studies investigating critical health effects induced from intravenous (i. v.) exposure to AgNPs was evaluated by the Annapolis Accords principles and Toxicological Data Reliability Assessment Tool (ToxRTool). The point of departure (POD) was based on an i. v. 28-day repeated AgNP (20 nm) dose toxicity study reporting an increase in relative spleen weight in rats with a 5% lower confidence bound of the benchmark dose (BMDL05) of 0.14 mg/kg bw/day. The POD was extrapolated to humans by a modifying factor of 1,000 to account for intraspecies variability, interspecies differences and lack of long-term toxicity data. The pTI for long-term i. v. exposure to 20 nm AgNPs released from blood-contacting medical devices was 0.14 μg/kg bw/day. This pTI may not be appropriate for nanoparticles of other physicochemical properties or routes of administration. The methodology is appropriate for deriving pTIs for nanoparticles in general
Real-time in vivo imaging of platelets, tissue factor and fibrin during arterial thrombus formation in the mouse
We have used confocal and widefield microscopy to image thrombus formation in real time in the microcirculation of a living mouse. This system provides high-speed, near-simultaneous acquisition of images of multiple fluorescent probes and of a brightfield channel. Vascular injury is induced with a laser focused through the microscope optics. We observed platelet deposition, tissue factor accumulation and fibrin generation after laser-induced endothelial injury in a single developing thrombus. The initiation of blood coagulation in vivo entailed the initial accumulation of tissue factor on the upstream and thrombus–vessel wall interface of the developing thrombus. Subsequently tissue factor was associated with the interior of the thrombus. Tissue factor was biologically active, and was associated with fibrin generation within the thrombus
Titanium Nitride Films for Ultrasensitive Microresonator Detectors
Titanium nitride (TiNx) films are ideal for use in superconducting
microresonator detectors because: a) the critical temperature varies with
composition (0 < Tc < 5 K); b) the normal-state resistivity is large, \rho_n ~
100 Ohm cm, facilitating efficient photon absorption and providing a large
kinetic inductance and detector responsivity; and c) TiN films are very hard
and mechanically robust. Resonators using reactively sputtered TiN films show
remarkably low loss (Q_i > 10^7) and have noise properties similar to
resonators made using other materials, while the quasiparticle lifetimes are
reasonably long, 10-200 s. TiN microresonators should therefore reach
sensitivities well below 10^-19 WHz^(-1/2).Comment: to be published in AP
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