The goal of the project described in this paper is to develop a human-adaptive Scrub Nurse Robot (SNR) that can adapt to surgeons with various levels of skill and experience in order to compensate ...for the present severe shortage of scrub nurses. To determine the specifications of the SNR, we analyzed real intraoperative behavior of a scrub nurse, and then modeled the entire surgical procedure with key participants by a multilevel modeling approach using the extended timed-automata-based formalism of Uppaal. Specifically, first, we videotaped the intraoperative motions of a scrub nurse and a surgeon in a thoracoscopic surgery performed on an infant pig, and analyzed their motions during the skin incision. Second, the motions of the nurse's right wrist, elbow, and shoulder were modeled with the timed automata. Third, the entire surgical procedure as well as actions and statuses of key participants was also modeled. Finally, it is shown that the proposed multilevel modeling approach also facilitates the model checking that is considered efficient in the SNR motion analysis and its adaptive motion planning.
DC excitation of transformers due to geomagnetically induced currents was studied by model experiments. First, differences in the DC excitation phenomenon due to the iron core structure were studied ...using three typical small-scale models. The results verified that single-phase three-legged cores were most susceptible and three-phase three-legged cores least susceptible to such excitation effects. Secondly, the local heating due to DC excitation was quantitatively assessed using large-scale core form and shell form models with the most susceptible single-phase three-legged cores. The results demonstrated that the maximum temperature rise was approximately 110/spl deg/C due to the GIC (200 A/3 phases).< >
Volume visualization of cerebral blood vessels is highly significant for diagnosis of the cerebral diseases. It is because the automated segmentation of the blood vessels from an MR angiography (MRA) ...image is a knotty problem that there are few works on it. This paper proposes an automated method to segment the blood vessels from 3D time of flight (TOF) MRA volume data. The method consists of: (1) removing the background, (2) volume quantization by watershed segmentation, and (3) classification of primitives by using an artificial neural network (NN). In the proposed method, the NN classifies each primitive, which is a clump of voxels, by evaluating the intensity and the 3D shape. The method was applied to seven MRA data sets. The evaluation was done by comparing with the manual classification results. The average classification accuracy was 80.8%. The method also showed the volume visualizations using target maximum intensity projection (target MIP) and surface shaded display (SSD). The evaluation by a physician showed that unclear regions on the conventional image were clearly depicted on applying the method, and that the produced images were quite interesting for diagnosis of cerebral diseases such as aneurysm and encephaloma. The quantitative and qualitative evaluations showed that the method was appropriate for blood vessel segmentation.
Segmentation of the surgeonpsilas hand movements during the surgery into more primitive parts and recognition of those parts using Kohonen map is discussed in present paper. Main advantages of the ...proposed approach are that it allows to take into account dynamical characteristics of the hand movements and exclude probability of human error in building etalon segmentation. Ability to recognize current action of the surgeon has a crucial importance in developing a robot able to assist surgeon during the endoscopic surgical operation. One of the possible ways is to predefine a set of possible surgeonpsilas actions and provide a recognition algorithm explored in the framework of present contribution.
To reduce cellular damage by pronuclear microinjection and nuclear transfer, we have recently developed a vibratory microinjection method. A micropipette was fixed to a piezoelectric ceramic with a ...resonance frequency of 70 kHz. When this micropipette was vibrated, it easily entered a mouse-fertilized egg without any sharp depression of the cell body, whereas a sharp, deep depression at the insertion site was observed when the micropipette was not vibrated. A depression rate defined as a rate of a depth of depression over an original cell diameter was utilized as an index of cellular deformation. The depression rates with and without vibration were 11.1 +/- 5.2% (N = 24) and 40.4 +/- 8.8% (N = 16), respectively (P < 0.0001, Student's t-test). In conclusion, the vibratory microinjection method is a new, useful option for gene transfer because it resulted in much less cellular deformation, therefore implicating less cellular damage.
This paper designs two Neural Network (NN) based systems for distinguishing and real-time recognition of internal organs on sequence of endoscopic images during abdominal surgery. First NN-based ...system proposed in this paper is designed for recognition of several different internal organs on color endoscopic images. Second NN-based system is designed for real-time recognition of presence of a particular internal organ on a sequence of color images (video stream) from endoscope. Restricted connectivity structure of the network makes possible decomposition of the image during the analysis and significantly reduces the number of parameters thus making training easier, faster and more accurate. The algorithms proposed in the paper are implemented in software application and their effectiveness is demonstrated on simulations.
We investigated the antithrombogenicity of magnetite (Fe3O4) by comparison with both segmented polyurethane (SPU) and glass. 1) Eight non-porous SPU tubes were made from 10% SPU solution by dipping ...an 8-mm glass rod 6 times into the solution. Each tube was then divided transversely in two. The inner surface of one part was covered with magnetite and the other part remained untreated. 2) Seven of 14 glass tubes were also covered with magnetite, and the others remained untreated. 3) Antithrombogenicity was evaluated from the clotting time of blood contained in each tube. The clotting time was determined with a damped oscillation-type rheometer. Magnetite-coated tubes and their respective non-coated counterparts were tested simultane-ously using the same blood. The clotting times in the magnetite-coated and non-coated SPU tubes were 39.9 ± 13.1 and 26.9 ± 8.9 min, respectively (p= 0.036). The clotting times in the magnetite-coated and non-coated glass tubes were 28.5 ± 6.9 and 2.7 ± 0.2 min, respectively (p= 0.018). A magnetite coating converted glass from a potent thrombogenic material to an antithrombogenic one, and also provided the surface even of SPU with significantly better antithrombogenicity. These results suggest that magnetite is antithrombogenic.
Flow disturbances in a model of an interposition graft in an arterial segment were measured using an ultrasound Doppler velocimeter. The effect of the degree of compliance mismatch between a stiff' ...graft' and compliant 'arterial' segments was investigated. In steady flow, disturbances were detected when the compliance ratio (stiff to compliant segments) was less than or equal to 0.1 and the Reynolds number greater than or equal to 2200. A recirculation zone just downstream of the distal anastomosis was observed at a Reynolds number greater than or equal to 2400. Disturbances were also measured under pulsatile flow which consisted of a time-varying component superimposed on a steady flow component. The time-varying flow component was either quasiphysiological or sinusoidal in shape. The Reynolds number was 500 but the frequency parameter varied from 4.2 to 8.5. Significant disturbances were observed for conduits with compliance ratio less than or equal to 0.19. The disturbance intensity tended to increase as the compliance ratio decreased and the frequency parameter increased. The magnitude of the disturbance was also greater with the quasiphysiological than the sinusoidal input flow waveform.
A divertor plasma is treated using a kinetic model to evaluate impurity control effects of an expanding magnetic field and effects of plasma‐neutral collisions on power transmission in a divertor ...chamber. Cold ions of fuel and ionized impurities are effectively trapped in the divertor chamber by the electrostatic potential caused by magnetic expansion if the ionization rate is smaller than an upper limit. Plasma‐neutral collisions remarkably reduce the impact energy of ions reaching the divertor plates through removal of energetic ions and through reduction of the potential drop in the divertor chamber.
We evaluated the influence of a cardiopulmonary bypass (CPB) system on coagulation and fibrinolytic factors: factors XII-II, AT III, plasminogen, protein C, vWF, TAT, PIC, FDP, fibrinogen, platelet ...count, PT and APTT. These were measured in 13 adult cases of open heart surgery (CPB time: 106±21min) before and after surgery, and on the first postoperative day (1 POD). All factors but APTT showed statistically significant changes with time, but the activities of factors XII, X and II, and protein C stayed within normal limits. The other factors went out of normal range. These factors, except factors VII and XI, were within or on the way back to normal range on 1 POD. The most abnormal activity of each coagulation factor was not so low as to cause postoperative bleeding tendency, which in fact was not found in any patients. These data suggest that the degree of activation of the coagulation and fibrinolytic cascades may be clinically acceptable although the CPB system significantly activates it. In addition, these data in this study can serve as control when a new CPB system is determined to have a better blood compatibility.
