Highly conductive, transparent films of In2−xSnxO3−y have been deposited by d‐c diode sputtering with Ar, O2, N2, Xe, and O2‐Ar mixtures. Sputtering targets with different In2O3/normalSnO2 ratios were utilized and the best results were obtained with pure Ar or Xe gas and targets containing 9–13 mole percent (m/o) SnO2 . The lowest film resistivity achieved was 1.77×10−4 normalohm‐normalcm , but routine films had resistivity values of about 3×10−4 normalohm‐normalcm . The use of a very low sputtering gas throughput (10−2–10−1 Torr liter/sec) was found to be necessary to develop films with a slight oxygen deficiency. Targets differing in density (porosity) differ in their susceptibility to reduction so that sputtering conditions depend on target density. The films have excellent adherence and will tolerate cleaning, heating, polishing, and bonding without failure. They may be etched in heated acids with standard photoresist techniques used to define electrode geometry. Exposure of the films to temperatures of 500 °C in air will cause an approximate factor of 3 increase in resistance at room temperature. Sputtered films with sheet resistance of 1.6 ohms/square, 73% light transmission, and 14% reflection at 500 nm have been obtained. Suitable antireflection coated films of 5–7 ohms/square possessing over 97% light transmission appear feasible.

Single-crystal lithium niobate has been used as a holographic storage medium. The material undergoes a change in refractive indices upon exposure to suitably intense light thus allowing it to act as a pure-phase, volume-holographic medium requiring no processing. The holograms formed have high diffraction efficiencies and are thermally erasable. The high resolution obtained suggests that such material may be useful in high-capacity, changeable optical information storage, processing and display devices.

A nationwide survey was undertaken to determine the rate of complications due to coronary arteriography during 1970-71. The responses from 173 hospitals-including a total of 46,904 coronary arteriograms-were analyzed in relationship to the technique employed and to the number of examinations performed at each hospital during the two-year period. The overall mortality rate was 0.45% (brachial 0.13%, femoral 0.78%). The mortality rate in institutions performing fewer than 200 examinations per two years was eight times higher than in institutions performing more than 800 examinations per two years. Similarly, the incidence of myocardial infarction and cerebral embolism was significantly higher when a smaller number of examinations was performed. The incidence of major complications-including death, myocardial infarction, and cerebral embolism-was higher in examinations using the femoral approach than the brachial approach. The incidence of arterial thrombosis and contrast agent reactions was higher for the brachial approach. Factors which may help to explain these differences are considered and discussed. Additional Indexing Words: Myocardial infarction Thrombosis PseudoaneurysmVentricular fibrillation Embolism Contrast agent reactions T HE COMPLICATION RATES of coronary arteriography reported in the literature vary widely.'-'8 Yet it is essential that accurate data be available if an intelligent and informed appraisal of risk vs yield is to be made prior to arteriography. For this reason, a nationwide survey was undertaken to gather information on arteriographic complications from hospitals of varying size and with varying frequencies of arteriographic examinations. Materials and MethodsA questionnaire ( fig. 1) was mailed to the director of the coronary arteriography laboratory at each of the 373 institutions with an open heart surgical team listed in the AMA Directory of Medical Schools and Affiliated Hospitals. There were 173 responses. The data were tabulated for each question according to the technique (brachial, femoral, and total) and to the number of cases performed in each institution. Written statements From the

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