Isolation and structure of higher diamondoids,nanometer-sized diamond molecules

We exploited the exceptional thermal stability and diverse molecular shapes of higher diamondoids (C22 and higher polymantanes) to isolate them from petroleum. Molecules containing 4 to 11 diamond-crystal cages were isolated and crystallized, and we obtained single-crystal x-ray structures for representatives from three families. Rigidity, strength, remarkable assortments of three- dimensional shapes, including resolvable chiral forms, and multiple, readily derivatizable attachment sites make them valuable nanometer-size molecular building blocks.     

Rapid method for extracting aldrin, dieldrin, and endrin from visceral material.

A simple method is described for purifying aldrin, dieldrin, and endrin from visceral material by using a Celite column. Celite retains all interfering materials including Lipids whereas the chlorinated Insecticides are eluted from the column with n-hexane. This extract can be used directly for gas chromatographic analysis.     

Effects of transportation on early embryonic death in mares

Incidence of early embryonic death (EED) and associated changes in serum cortisol, progesterone and plasma ascorbic acid (AA) in transported mares were investigated. Mares were transported for 472 km (9 h) during either d 16 to 22 (T-3 wk, n = 15) or d 32 to 38 (T-5 wk, n = 15) of gestation. Blood samples were drawn from control, nontransported mares (NT-3 wk, NT-5 wk, n = 24) and transported mares pre-trip, midtrip, and at 0, 12, 24, 48 and 72 h post-transport and daily for the next 2 wk. Incidence of EED between transported and nontransported mares was not different (P greater than .05). Serum cortisol in all transported mares increased (P less than .05) relative to pre-trip values at midtrip and 0 h post-transport. Relative to NT mares, serum cortisol was higher (P less than .05) at midtrip in T-3 wk mares and 0 h post-transport in T-5 wk mares. Serum progesterone in all T mares increased (P less than .05) at midtrip relative to pre-trip values and was higher (P less than .05) in T-3 wk mares than in NT-3 wk mares at midtrip and 0 h post-transport. Post-transport decreases (P less than .05) in concentrations of progesterone were observed in mares that aborted. Plasma AA in transported mares increased (P less than .05) at midtrip in T-5 wk mares and decreased (P less than .05) relative to pre-trip values at 24 and 48 h post-transport (T-3 wk and T-5 wk mares, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

On atmospheric loss of oxygen ions from earth through magnetospheric processes

In Earth's environment, the observed polar outflow rate for O(+) ions, the main source of oxygen above gravitational escape energy, corresponds to the loss of approximately 18% of the present-day atmospheric oxygen over 3 billion years. However, part of this apparent loss can actually be returned to the atmosphere. Examining loss rates of four escape routes with high-altitude spacecraft observations, we show that the total oxygen loss rate inferred from current knowledge is about one order of magnitude smaller than the polar O(+) outflow rate. This disagreement suggests that there may be a substantial return flux from the magnetosphere to the low-latitude ionosphere. Then the net oxygen loss over 3 billion years drops to approximately 2% of the current atmospheric oxygen content.     

Lithophagic snail from southern British Honduras

A freshwater gastropod, Pachycheilus glaphyrus, responsible for unusual erosion in limestone has been located in southern British Honduras where it is abundant in streams flowing through areas of karst topography. These snails ingest algae that proliferate in solution grooves formed at the fluctuating air-water interface. Rasping action of the radula results in deepening of these grooves and appears to improve the algal habitat.     

Observations at venus encounter by the plasma science experiment on mariner 10

Preliminary results from the rearward-looking electrostatic analyzer of the plasma science experiment during the Mariner 10 encounter with Venus are described. They show that the solar-wind interaction with the planet probably involves a bow shock rather than an extended exosphere, but that this is not a thin boundary at the point where it was crossed by Mariner 10. An observed reduction in the flux of electrons with energies greater than 100 electron volts is interpreted as evidence for somne direct interaction with the exosphere. Unusual intermittent features observed downstream of the planet indicate the presence of a comet-like tail hundreds of scale lengths in length.