Image degradation due to wavefront aberrations can be corrected with adaptive optics (AO). In a typical AO configuration, the aberrations are measured directly using a Shack-Hartmann wavefront sensor and corrected with a deformable mirror in order to attain diffraction limited performance for the main imaging system. Wavefront sensor-less adaptive optics (SAO) uses the image information directly to determine the aberrations and provide guidance for shaping the deformable mirror, often iteratively. In this report, we present a Deep Reinforcement Learning (DRL) approach for SAO correction using a custom-built fluorescence confocal scanning laser microscope. The experimental results demonstrate the improved performance of the DRL approach relative to a Zernike Mode Hill Climbing algorithm for SAO.
Studies were made on dogs at various times up to one year following the coronary sinus anastomosis of Beck to determine the chronic effects of the operation. The results indicate that the graft perfuses the capillary bed of the occluded circumflex artery for about five weeks after the operation and then loses its functional contact with the capillary bed probably because of obliterative venous changes. However, as a result of an anoxia, there is definite development of intercoronary collateral vessels during the first few weeks, which persist throughout the year even though there is no arterial occlusion. It is concluded that in dogs the Beck operation is protective against the major effects of coronary ligation because of retrograde capillary flow early and intercoronary anastomoses later.
Using anesthetized dogs, the possible antiadrenergic effects of nitroglycerin upon the myocardium were studied. Observations were made upon changes in heart rate, myocardial oxygen consumption, systolic vigor, and the electrocardiograms. Data are presented showing the effects of nitroglycerin and adrenergic agents when given separately and in combination. Results indicate that in dogs, nitroglycerin produces no antiadrenergic effects on the myocardium. The suggestion is made that the T wtave changes seen after adrenergic stimulation in dogs may not be due to anoxia.T HE beneficial effects of nitroglycerin in the anginal syndrome have been considered to be due either to coronary dilation with an improvement in myocardial oxygenation, or to the reduction in peripheral resistance and cardiac work, or to both, resulting in a decrease in myocardial oxygen re-(luirement. However, in view of recent evidence of heart rate and electrocardiographic changes in atropinized cats, Raab'1 suggests that nitroglycerin acts in a different manner. He postulates that it interferes with the metabolic, anoxia producing effects of the sympathomimetic amines on the myocardium. Although this hypothesis is attractive, Raab admits that its proof depends upon further evidence.The question then arises as to the criteria required for more conclusive study of this problem. Large increases in myocardial oxygen (oasumption electrocardiogram which is seen after adrenergic stimulation is due to anoxia or to some other myocardial effect of adrenergic agents is more difficult to establish. (See Discussion.) There are, however, two changes induced by adrenergic agents which occur together, and which can serve as indicators for testing any deviation in the adrenergic effects upon the myocardium. These are (1) changes in vigor of contraction, as indicated in the aortic pressure pulse, and (2) changes in myocardial oxygen consumption.'-8 The present report deals with our attempts to modify these adrenergically induced myocardial changes in dogs by the use of nitroglycerin. METHODSDogs were anesthetized with pentobarlital, and under artificial respiration the left chest was opened between the third and fourth ribs. The blood was made noncoagulable with 100 to 150 mg. of heparin. The left jugular vein was cannulated to administer fluid and to return coronary sinus blood. The coronary sinus was cannulated via the right auricle, and the cannula was made secure in the sinus by the inflation of a small balloon at the cannula tip.The left common coronary artery was dissected free and was cannulated by means of the special cannula previously described.9 The cannula was connected to the constant pressure apparatus andl a Shiplev rotameter described elsewhere.8' 10 In a few cases adjustment of the position of the cannula was necessary to get adequate sealing without leakage or restriction of coronary inflow. The possibility of leakage was tested in two ways: (1) With perfusion pressure above aortic pressure, a ligature was tightened about the common left art...
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