Analog Simulation of Problem of Heat Conduction Using Electric Resistive Circuits and Analog Memories

A method of analog simulation of problems of heat conduction using electric resistive circuits and analog memories is proposed. The principle of this method is to derive the difference equations corresponding to given problems and to simulate these difference equations by using resistive circuits accompanied with analog memories. Discussions of the practical set-up procedures for constructing the resistive circuits are given according to the various problems of heat conduction. By using this method, the approximate solutions of typical problems of heat conduction are easily obtained with considerable accuracy

Hereditary pancreatic cancer

Pancreatic cancer is associated with both family and hereditary cancer syndromes. Multigene panel testing for pancreatic cancer detected the germline variants BRCA1/2, PALB2, ATM, TP53, MLH1, STK11/LKB1, APC, CDKN2A, and SPINK1/ PRSS1 as high-risk genes. A latest genome-wide association study revealed the common, but low-risk germline variants in pancreatic cancer patients. Active pancreatic surveillance using magnetic resonance imaging and endoscopic ultrasound is recommended for high-risk individuals who have a family history of pancreatic cancer or harbor these germline pathogenic variants to improve the detection rate and prognosis of pancreatic cancer. Since poly-ADP-ribose polymerase (PARP) inhibitor has been shown to be effective in improving the prognosis of BRCA -positive pancreatic cancer as well as hereditary breast and ovarian cancer syndrome, PARP inhibitor therapy is currently being applied as precision medicine to pancreatic cancer patients harboring the BRCA1/2 germline variant. This review highlights the importance of surveillance for germline pathogenic variants in pancreatic cancer and is expected to lead to improvements in the diagnosis and prevention of pancreatic cancer as well as facilitate the development of effective therapeutic strategies and precision medicine

Vision-based Vehicle Navigation Using the Fluorescent Lamp Array on the Ceiling

In this paper, autonomous navigation based on a TV vision system on board a vehicle is proppsed. Our method is to use fluorescent lamp arrays on the ceiling as a lighthouse for vehicle motion. First, experimental study of vehicle control based on information from photo-sensors, set up on a TV screen, is worked out using an actual size model. Then, numerical simulations for this control scheme are carried out in detail. Moreover, a more vision-based approach is investigated which extracts information aspects from the images of fluorescent lamp arrays to realize more exact motion along the lamp array. Finally, a practical autonomous vehicle which is controlled by a photo-sensor system is constructed and its experimental results are shown

Raman spectroscopic studies on the ferroelectric soft mode in SnxSr1-xTiO3

The Raman spectra of novel ferroelectric ceramics SnxSr1-xTiO3 (x = 0.1, 0.05 and 0.02) were obtained to clarify the mechanism of their ferroelectric phase transitions. Two transverse-optic modes in the ferroelectric phase showed softening toward the ferroelectric transition temperature. A comparison of the spectra obtained for SnxSr1-xTiO3 with the spectrum of PbxSr1-xTiO3 facilitated the assignment of the observed modes under the assumption of the ferroelectric phase in C4v1 symmetry. However, several peaks violating the Raman selection rules were observed, suggesting the emergence and growth of polar regions even in the paraelectric phase

Regional cerebral tissue blood flow measured by the colored microsphere method during retrograde cerebral perfusion

AbstractBrain tissue blood flow was measured precisely by the colored microsphere method during retrograde cerebral perfusion in 10 normothermic mongrel dogs. The average tissue blood flow rates to the cerebral cortex, cerebral medulla, brain stem, cerebellum, and spinal cord during retrograde cerebral perfusion at 25 mm Hg of external jugular venous pressure were 10.5 ± 10.3, 4.2 ± 4.6, 11.1 ± 9.8, 12.3 ± 8.6, and 9.1 ± 5.8 ml/min per 100 gm, respectively. The brain was perfused wholly by retrograde cerebral perfusion without lateralization. Total cerebral blood flow was calculated as the sum total rates of blood flow to each area. Total cerebral blood flow during retrograde cerebral perfusion at 25 mm Hg was 7.8 ± 4.4 ml/min, which represented 3.5% ± 1.9% of whole body blood flow and one third of the total cerebral blood flow (28.0 ± 4.2 ml/min) during cardiopulmonary bypass at a flow rate of 1000 ml/min. Oxygen consumption and carbon dioxide elimination by the total cerebrum during retrograde cerebral perfusion at 25 mm Hg were 0.54 ± 0.23 ml/min and 34 ± 15 μmol/min, respectively, or 8.6% ± 3.6% and 7.0% ± 3.1% of the corresponding whole body value and represented about one third of that measured during cardiopulmonary bypass (1.21 ± 0.39 ml/min and 96 ± 15 μmol/min). Total cerebral blood flow, total cerebral oxygen consumption, and carbon dioxide elimination increased as the external jugular venous pressure increased from 15 to 25 mm Hg; however, no further increase occurred once the external jugular venous pressure exceeded 25 mm Hg. (J THORAC CARDIOVASC SURG 1995;109:772-9