772 research outputs found
Skin Segmentation and Skull Segmentation for Medical Imaging
In this paper aims we present tools for medical imaging applications to do skin and skull segmentation in a short time. The desired output for skin segmentation is a 3D visualization of the facial skin without any cavities or holes inside the head, while skull segmentation aims to create a 3D visualization of the skull bones. The algorithm used for skin segmentation is thresholding the image, extracting the largest connected component, and holefilling to fill the unnecessary holes. As for the skull segmentation, the process is done by removing the spines which is connected to the skull, and then extracting the largest connected component. Afterwards, mesh generation is done to produce the 3D objects from the processed images. This mesh generation process is done using the marching cubes algorithm. The testing results show that the skin and skull segmentation process will work well when there are no other objects that are connected to the skin or the skull. Skin segmentation process takes a significant amount of time, primarily caused by the holefilling process
Triggering Mechanisms for Motor Actions: The Effects of Expectation on Reaction Times to Intense Acoustic Stimuli
Motor actions can be released much sooner than normal when the go-signal is of very high intensity (>100 dBa). Although statistical evidence from individual studies has been mixed, it has been assumed that sternocleidomastoid (SCM) muscle activity could be used to distinguish between two neural circuits involved in movement triggering. We summarized meta-analytically the available evidence for this hypothesis, comparing the difference in premotor reaction time (RT) of actions where SCM activity was elicited (SCM+ trials) by loud acoustic stimuli against trials in which it was absent (SCM- trials). We found ten studies, all reporting comparisons between SCM+ and SCM- trials. Our mini meta-analysis showed that premotor RTs are faster in SCM+ than in SCM- trials, but the effect can be confounded by the variability of the foreperiods employed. We present experimental data showing that foreperiod predictability can induce differences in RT that would be of similar size to those attributed to the activation of different neurophysiological pathways to trigger prepared actions. We discuss plausible physiological mechanisms that would explain differences in premotor RTs between SCM+ and SCM- trials
Evacuation of the Pleural Cavity With an Infant Feeding Catheter Following en Bloc Resection of Hepatocellular Carcinoma and Involved Diaphragm–an Institutional Experience
En bloc resection of hepatocellular carcinoma and
the involved diaphragm will, towards the end of
operation, require evacuation of the pleural cavity,
usually with a chest drain. We describe our method
and experience of evacuating the pleural cavity, at
the time of diaphragmatic repair, with an infant
feeding catheter without the need of a chest drain.
We have found the method safe and efficacious
Cholangiographic Features in the Diagnosis and Management of Obstructive Icteric Type Hepatocellular Carcinoma
In 11 years and 3 months, 2037 patients with HCC
were seen and 48 patients (2.4%) were diagnosed to
have obstructive icteric type HCC. Five patients
were terminally ill and were not investigated further.
Forty three patients were initially investigated
by endoscopic retrograde cholangiography (ERC) or
percutaneous transhepatic cholangiogram (PTC) and
classified as having obstructive icteric type 1, 2, or 3
HCC based on the cholangiographic findings. The
obstruction in type 1 HCC was due to intraluminal
tumour casts and/or tumour fragments obstructing
the hepatic ductal confluence or common bile duct,
while intraluminal blood clots, from haemobilia,
filling the biliary tree was the cause in type 2 HCC.
The pathology in type 3 HCC was extraluminal
obstruction by extensive tumour encasement of the
intra–hepatic biliary ductal system and/or extrinsic
compression of the hepatic and common bile ducts
by tumour(s) and/or malignant lymph nodes. At
the initial ERC/PTC, 10 patients (5 resected, 50%)
had obstructive icteric type 1 and 23 patients (0 resected)
had obstructive icteric type 3 HCC. Of the 10
patients initially classified according to cholangiography
to have obstructive icteric type 2 HCC,
subsequent investigations revealed that 6 patients
had type 1 HCC (4 resectable, 67%) and 4 patients
had type 3 HCC (0 resectable). The classification of
the obstructive icteric type HCC into types 1, 2, and
3, based on the initial cholangiographic appearances
has simplified and rationalized our management
strategy for this condition
Characterization of electromagnetic valveless micropump
This paper presents an electromagnetically-actuated micropump for microfluidic application. The system comprises two modules; an electromagnetic actuator module and a diffuser module. Fabrication of the diffuser module can be achieved using photolithography process with a master template and a PDMS prepolymer as the structural material. The actuator module consists of two power inductors and two NdFeB permanent magnets placed between the diffuser elements. The choice of this actuation principle merits from low operating voltage (1.5 Vdc) and the flow direction can be controlled by changing the orientation of the magnet vibration. Maximum volumetric flow rate of the fabricated device at zero backpressure is 0.9756 μLs-1 and 0.4659 μLs-1 at the hydrostatic backpressure of 10 mmH2O at 9 Hz of switching speed
Analysis Air Cooling Mechanism for Photovoltaic Panel by Solar Simulator
Measurement the outdoor efficiency of photovoltaic (PV) panels is essential, but it is not likely an exceptional circumstance at any given moment is always repeating itself. A solar simulator was designed and fabricated for the purpose of analyzing the performance of PV panel with and without an air cooling mechanism in indoor test. Twenty units of 500 W halogen lamps with build-in reflector support by the steel structure holder act as a natural sunlight. The uniformity of the solar radiation was measured in the test area. Two units of PV panel with same characteristics were experimental in three sets of uniformity of solar radiation, which are 620, 821 and 1016 W/m². The operating temperature of PV panel with an air cooling mechanism can be decreased 2-3 ˚C compared to PV panel reference. The PV panel with an air cooling mechanism can be increased in 3-7 % of maximum power output based on solar radiation. An overall method and procedure of the measurement by the solar simulator are discussed and proposed
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