Research and Development Progress Report 590

"For the past several years, the Rocketdyne Research Division has, under the sponsorship of the Office of Saline Water, engaged in a study of the application of electrochemical techniques to the demineralization of brackish water. Early work in this program was concerned with a mechanistic study of electrochemically induced demineralization at chemically treated carbon electrodes. The results of this study led to the development of a process called electrochemically controlled ion-exchange" (p. 2)

Solar-insolation-induced changes in the coma morphology of comet 67P/Churyumov-Gerasimenko. Optical monitoring with the Nordic Optical Telescope

Context. 67P/Churyumov-Gerasimenko (67P/C-G) is a short-period Jupiter family comet with an orbital period of 6.55 years. Being the target comet of ESA’s Rosetta mission, 67P/C-G has become one of the most intensively studied minor bodies of the Solar System. The Rosetta Orbiter and the Philae Lander have brought us unique information about the structure and activity of the comet nucleus, as well as its activity along the orbit, composition of gas, and dust particles emitted into the coma. However, as Rosetta stayed in very close proximity to the cometary nucleus (less than 500 km with a few short excursions reaching up to 1500 km), it could not see the global picture of a coma at the scales reachable by telescopic observations (103 - 105 km). Aims. In this work we aim to connect in-situ observations made by Rosetta with the morphological evolution of the coma structures monitored by the ground-based observations. In particular, we concentrate on causal relationships between the coma morphology and evolution observed with the Nordic Optical Telescope (NOT) in the Canary Islands, and the seasonal changes of the insolation and the activity of the comet observed by the Rosetta instruments. Methods. Comet 67P/C-G was monitored with the NOT in imaging mode in two colors. Imaging optical observations were performed roughly on a weekly basis, which provides good coverage of short- and long-term variability. With the three dimensional modeling of the coma produced by active regions on the Southern Hemisphere, we aim to qualify the observed morphology by connecting it to the activity observed by Rosetta. Results. During our monitoring program, we detected major changes in the coma morphology of comet 67P/C-G. These were longterm and long-lasting changes. They do not represent any sudden outburst or short transient event, but are connected to seasonal changes of the surface insolation and the emergence of new active regions on the irregular shaped comet nucleus. We have also found significant deviations in morphological changes from the prediction models based on previous apparitions of 67P/C-G, like the time delay of the morphology changes and the reduced activity in the Northern Hemisphere. According to our modeling of coma structures and geometry of observations, the changes are clearly connected with the activity in the Southern Hemisphere observed by the Rosetta spacecraft

The new calcium antagonist lercanidipine and its enantiomers affect major processes of atherogenesis in vitro: is calcium entry involved?

Atherosclerosis results from multiple factors and involves several mechanisms, including endothelial monocyte and smooth muscle cell (SMC) changes, cholesterol accumulation, plaque rupture and thromboembolism. Calcium ions play a role in the initial and chronic development of atherosclerotic lesions. Several studies in experimental animal models have demonstrated the potential direct antiatherosclerotic effects of calcium antagonists. In this study the antiatherogenic activity of lercanidipine, a new lipophilic, second-generation calcium antagonist, was investigated. Lercanidipine and its enantiomers inhibited the replication and migration of arterial myocytes in concentrations ranging from 10 to 50 microM. The antiproliferative effect of lercanidipine was dose dependent, with a potency similar to that of lacidipine and nifedipine, and was unrelated to the stereoselectivity of enantiomers to bind L-type calcium channels. Lercanidipine and its enantiomers (25 microM) decreased the serum-induced elevation of [Ca2+]i in SMC, with the (S)-enantiomer (69% inhibition) being 2.4-fold more active than the (R)-counterpart (29% inhibition). The studies performed with enantiomers of lercanidipine suggest that the observed effects are not related to the blockade of voltage-dependent Ca2+ channels and confirm, at least in vitro, the pharmacological potential of the compound to influence negatively the process of atherogenesis

Leukotriene D(4)-induced activation of smooth-muscle cells from human bronchi is partly Ca(2+)-independent

Cysteine-containing leukotrienes (cysteinyl-LTs) are potent bronchoconstrictors and play a key role in asthma. We found that histamine and LTD, markedly constrict strips of human bronchi (HB) with similar efficacy. However, in human airway smooth-muscle (HASM) cells, LTD(4), at variance with histamine, elicited only a small, transient change in intracellular calcium ion concentration. HASM cells express both Ca(2+)-dependent and -independent isoforms of protein kinase C (PKC) (i.e., PKC-alpha and PKC-epsilon). Western blot analysis showed that PKC-alpha is activated by histamine and, to a lesser extent, by LTD(4), whereas only LTD(4) translocates PKC-epsilon. This translocation was specifically inhibited by the LTD4 antagonist pobilukast. Phorbol-dibutyrate ester (PDBu) (a PKC activator) contracted HE strips to the same extent in the presence as in the absence of extra- and intracellular Ca(2+). In the absence of Ca(2+), LTD(4) contracted HB strips to the same extent as did PDBu, suggesting the involvement of a Ca(2+)-independent PKC in LTD(4)-mediated signal transduction. PDBu-induced desensitization and the PKC inhibitor H7 abolished the slow and sustained LTD(4)-triggered contraction of HE strips in the absence of Ca(2+), although H7 did not greatly affect the response in the presence of the ion. Thus, in human airways, we identified a novel LTD(4) transduction mechanism linked to bronchial smooth-muscle contraction, which is partly independent of Ca(2+) and involves the activation of PKC-epsilon

The search campaign to identify and Image the Philae Lander on the surface of comet 67P/Churyumov-Gerasimenko

On the 12th of November 2014, the Rosetta Philae Lander descended to make the first soft touchdown on the surface of a comet – comet 67P/Churyumov- Gerasimenko. That soft touchdown did occur but due to the failure in the firing of its two harpoons, Philae bounced and travelled across the comet making contact with the surface twice more before finally landing in a shaded rocky location somewhere on the southern hemisphere of the comet. The search campaign, led by ESA, involved multiple teams across Europe with a wide range of techniques used in support of it. This search campaign would continue through 2015 where a prime candidate on the surface was identified and on into 2016 to end on the 2nd of September 2016 when a definitive and conclusive image was taken of the lander on the surface of the comet, confirming the prime candidate to indeed be Philae

Office of Saline Water Reports

From Summary: "The results of such experiments are summarized as follows: 1. Anion-responsive electrodes formed with Kraton, graphite, Norit, and Amberlite CG-4B demineralized well at currents up to 10 milli-amperes; regeneration was efficient up to 8 milliamperes. 2. Satisfactory anion-responsive electrodes containing Amberlite IRA-68 could only be formed when resin was first ground while in the sulfate form; it was required that it be added to the paste mixture (Kraton, Norit, and graphite) in the same form.