34,543 research outputs found
Web-based interface system for bedside monitor
From face-to-face consultation to medicine at a distance, technology is changing the way medical services are delivered to the people. We are going into an era where the information is being digitized to be stored in a database. This is done in order to reduce information overlap and redundancy that are the main problems the health care sector are facing right now. More hospitals in other more advanced countries are going paperless. In order to provide better services to the critically ill patients in the ICU or CCU, a data acquisition program is developed for the acquisition of vital signs monitored in the critical care units. This work discusses the work done in extracting the data and signal from patient monitor BSM 8800 to the computer. The data are acquired using RS232C Interface Protocol. The vital signs acquired include oxygen saturation (SaCh), heart rate (HR), electrocardiograph (ECG) signal, non-invasive blood pressure (NIBP), respiration rate (RR), temperature (TEMP) and end tidal carbon dioxide (PETCO2 or ETCO2). Ventricular Premature Contraction (VPC), ST level and arrhythmia information are also acquired and displayed to provide a more thorough information on the condition of the patients. Alarm detection is also programmed so that in critical conditions the vital signs will be displayed in red for extra caution. An ECG user control is designed and embedded in the web page in order to convert and plot the ECG waveform from hexadecimal values sent from the bedside monitor. The user control has been tested its accuracy and proved its validity to reconstruct the original ECG waveform. Basic patient information can also be seen from the graphical user interface (GUI) that has been developed. Physicians and medical practitioners have to register with the system before gaining access to the system and only the physician-in-charge of the patient can see the more intricate details of the patient
Homogeneous optical cloak constructed with uniform layered structures
The prospect of rendering objects invisible has intrigued researchers for
centuries. Transformation optics based invisibility cloak design is now
bringing this goal from science fictions to reality and has already been
demonstrated experimentally in microwave and optical frequencies. However, the
majority of the invisibility cloaks reported so far have a spatially varying
refractive index which requires complicated design processes. Besides, the size
of the hidden object is usually small relative to that of the cloak device.
Here we report the experimental realization of a homogenous invisibility cloak
with a uniform silicon grating structure. The design strategy eliminates the
need for spatial variation of the material index, and in terms of size it
allows for a very large obstacle/cloak ratio. A broadband invisibility behavior
has been verified at near-infrared frequencies, opening up new oppotunities for
using uniform layered medium to realize invisibility at any frequency ranges,
where high-quality dielectrics are available
Macroscopic invisibility cloaking of visible light
Invisibility cloaks, which used to be confined to the realm of fiction, have now been turned into a scientific reality thanks to the enabling theoretical tools of transformation optics and conformal mapping. Inspired by those theoretical works, the experimental realization of electromagnetic invisibility cloaks has been reported at various electromagnetic frequencies. All the invisibility cloaks demonstrated thus far, however, have relied on nano- or micro-fabricated artificial composite materials with spatially varying electromagnetic properties, which limit the size of the cloaked region to a few wavelengths. Here, we report the first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding, for a specific light polarization, three-dimensional objects of the scale of centimetres and millimetres. Our work opens avenues for future applications with macroscopic cloaking devices
Discovery of highly spin-polarized conducting surface states in the strong spin-orbit coupling semiconductor SbSe
Majority of the AB type chalcogenide systems with strong spin-orbit
coupling, like BiSe, BiTe and SbTe etc., are
topological insulators. One important exception is SbSe, where a
topological non-trivial phase was argued to be possible under ambient
conditions, but such a phase could be detected to exist only under pressure. In
this Letter, we show that like BiSe, SbSe, displays generation
of highly spin-polarized current under mesoscopic superconducting point
contacts as measured by point contact Andreev reflection spectroscopy. In
addition, we observe a large negative and anisotropic magnetoresistance in
SbSe, when the field is rotated in the basal plane. However, unlike in
BiSe, in case of SbSe a prominent quasiparticle interference
(QPI) pattern around the defects could be obtained in STM conductance imaging.
Thus, our experiments indicate that SbSe is a regular band insulator
under ambient conditions, but due to it's high spin-orbit coupling, non-trivial
spin-texture exists on the surface and the system could be on the verge of a
topological insulator phase.Comment: 5 pages, 4 figures, supplemental material not include
The second order local-image-structure solid
Characterization of second order local image structure by a 6D vector ( or jet) of Gaussian derivative measurements is considered. We consider the affect on jets of a group of transformations - affine intensity-scaling, image rotation and reflection, and their compositions - that preserve intrinsic image structure. We show how this group stratifies the jet space into a system of orbits. Considering individual orbits as points, a 3D orbifold is defined. We propose a norm on jet space which we use to induce a metric on the orbifold. The metric tensor shows that the orbifold is intrinsically curved. To allow visualization of the orbifold and numerical computation with it, we present a mildly-distorting but volume-preserving embedding of it into euclidean 3-space. We call the resulting shape, which is like a flattened lemon, the second order local-image-structure solid. As an example use of the solid, we compute the distribution of local structures in noise and natural images. For noise images, analytical results are possible and they agree with the empirical results. For natural images, an excess of locally 1D structure is found
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