Krypton, xenon found in Mars' atmosphere Viking scientists have identified two I xenon are present, but they are both more elements in Mars' atmo very low. However, data from their sphere—the noble gases krypton and gas chromatography-mass spec xenon. Early data from Viking I trometry experiment clearly show hinted that at least one of these ele that several isotopes of krypton are ments, krypton, might be present in present and in about the relative the atmosphere in trace amounts. abundance that they are found both Now its presence is confirmed along on earth and in meteorites. Xenon with that of xenon in a more sensitive also can be clearly seen in the GC-MS experiment conducted by Viking II, data. Its molecular weight puts it near the second and final unmanned probe the edge of the sensitivity range of the to land on Mars as part of the Na Viking equipment; thus its isotopes, tional Aeronautics & Space Admin if present, are obscured. istration's current project of explo One thing that is quite clear from ration of that planet. The newly de the GC-MS data is that krypton is tected elements join nitrogen-14 and more abundant than xenon in Mars' 15; argon-36, 38, and 40; and nitric atmosphere. This is true of the earth's oxide as components of Mars' atmo atmosphere as well, but it is not the sphere first discovered by Viking. case for meteorites, believed by many From the Viking data, Mars' at to be a model of the material from mosphere appears to be about 95% which the planets were formed. On carbon dioxide. Its other major com earth, xenon is believed to be deplet ponents appear to be nitrogen, argon, ed from the atmosphere by absorp molecular oxygen, and nitric oxide. tion into sedimentary rocks, which NASA scientists do not know yet raises the question of whether that D what concentrations of krypton and I has happened on Mars.
Upjohn scientists synth size thromboxane Scientists at Upjohn Co. have syn thesized thromboxane B2 (TXB 2 ), a prostaglandin-related compound heretofore detected only in trace amounts in tissues. According to the company, the achievement will make it possible to produce relatively large amounts of T X B 2 for investigation of such processes as blood clotting and maintenance of arterial smooth muscle tone, and of its role in such diseases as asthma, coronary heart disease, and stroke. Upjohn notes that although T X B 2 is known to have some biological ac tivity in raising blood pressure and in contracting smooth muscle, it hasn't yet been studied extensively. TXB 2 is a relatively stable substance formed in cells from thromboxane A2 (TXA 2 ). TXA 2 is a potent but short lived constrictor of arteries and bronchial tubes. It also stimulates aggregation of blood platelets. Be cause detection of T X B 2 in cells and tissues indicates that TXA 2 is being produced, Upjohn speculates that tests for T X B 2 could be used to eval uate drugs designed to suppress "in appropriate" synthesis of TXA 2 . Detailed accounts of the T X B 2 work appear in the September issue of Tetrahedron Letters. Dr. William P. Schneider and Raymond A. Morge describe a practical four-step syn thesis of T X B 2 using as starting ma terial a derivative of prostaglandin F 2 a , already in commercial produc tion. Also, Dr. Norman A. Nelson and β
C&EN Sept. 27, 1976
Robert W. Jackson describe "total synthesis" of the compound. Upjohn notes that thromboxanes are formed in the body from arachidonic acid. Normally stored in phospholipids, the acid is released as needed to combine with oxygen to form prostaglandin endoperoxides. The endoperoxides may be further converted either to prostaglandins or thromboxanes. Work by Dr. Robert C. Kelly, Use Schletter, and Shirley J. Stein delin eated the previously unknown struc ture of one portion of the T X B 2 mol ecule. Molecular structures of thromboxanes originally had been deduced by Dr. Bengt Samuelsson and Dr. Mats Hamberg in Sweden. The Upjohn scientists also pre pared several intermediate com pounds that may lead to production of synthetic thromboxane analogs. These, like prostaglandin analogs, could be valuable in studying body chemistry and diseases. D
Nuclear still offers cheapest electricity The nuclear power industry has been taking a lot of knocks lately, what with questions about safety, future uranium supplies, and recycling or storing wastes from spent fuel. But there's some good news on at least one front—nuclear generating plants al ready operating in the U.S. are con-
Nuclear power plants in U.S. generated 81 billion kwh in first-half 1976
tinuing to produce electricity at a lower cost than are coal- or oil-fueled plants. Further, total electricity gen erated by nuclear energy in the U.S. is increasing. Nuclear opponents may not be happy about this increase, but it has accounted for a fuel savings of more than 5 billion gal of oil or 27 million tons of coal for a savings of about $625 million during the first half of this year, according to a survey of utility companies just completed by the Atomic Industrial Forum. The survey finds that the total cost of producing 1 kwh with nuclear en ergy in first-half 1976 averaged 1.5 cents. This is 59% less than the 3.6 cent-per-kwh cost using oil, and 18% less than the 1.8 cents per kwh using coal. AIF points out that all three fuel categories showed increases in total generating costs over the comparable 1975 period. In last year's first half, it cost 1.1 cents to produce 1 kwh with nuclear energy, 3.3 cents with oil, and 1.5 cents with coal. In compiling these costs for its survey, AIF asked utilities to include capital costs, carrying charges, in terest, insurance, operation and maintenance, taxes, and the like, as well as costs incurred when units are not in operation, and, in the case of nuclear, also to include allowances for future waste management. In terms of electricity generation, nuclear power accounted for 81 bil lion kwh during first-half 1976, 8.3% of total electricity generation in the U.S. during that period, and 5 billion kwh more than during the same pe riod last year. AIF says it expects nuclear energy's share of electricity generation to be 9 to 10% by year's end. The survey finds there are 61 op erable nuclear power reactors in the U.S. with a combined generating ca pacity of about 42,700 Mw. There are 76 reactors with construction permits (nearly 80,000 Mw), 19 with limited work authorizations (20,300 Mw), and 63 on order (72,000 Mw). D
