Moytirra:Discovery of the first known deep-sea hydrothermal vent field on the slow-spreading Mid-Atlantic Ridge north of the Azores

Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra vent field at 45^oN. This is the only high temperature hydrothermal vent known between the Azores and Iceland, in the North Atlantic and is located on a slow to ultraslow-spreading mid-ocean ridge uniquely situated on the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crest. Furthermore, the Moytirra vent field is, unusually for tectonically controlled hydrothermal vents systems, basalt hosted and perched midway up on the median valley wall and presumably heated by an off-axis magma chamber. The Moytirra vent field consists of an alignment of four sites of venting, three actively emitting "black smoke," producing a complex of chimneys and beehive diffusers. The largest chimney is 18 m tall and vigorously venting. The vent fauna described here are the only ones documented for the North Atlantic (Azores to Reykjanes Ridge) and significantly expands our knowledge of North Atlantic biodiversity. The surfaces of the vent chimneys are occupied by aggregations of gastropods (Peltospira sp.) and populations of alvinocaridid shrimp (Mirocaris sp. with Rimicaris sp. also present). Other fauna present include bythograeid crabs (Segonzacia sp.) and zoarcid fish (Pachycara sp.), but bathymodiolin mussels and actinostolid anemones were not observed in the vent field. The discovery of the Moytirra vent field therefore expands the known latitudinal distributions of several vent-endemic genera in the north Atlantic, and reveals faunal affinities with vents south of the Azores rather than north of Iceland. © 2013. American Geophysical Union. All Rights Reserved.

Starting slow: the effects of response-switching frequency on patterns of cardiovascular reactivity

Research findings suggest that switching between competing response sets can be resource demanding. The current study focused on concurrent health-relevant physiological effects of task switching by assessing cardiovascular response at varying levels of switch frequency. The participants performed a response-switching task at three different levels of response set switching frequency (low, medium and high) while measurements of blood pressure and heart rate were taken. One group was exposed to response-switching frequency conditions in the order low → medium → high, while the other group was exposed to the same task conditions in the reverse order (i.e. high → medium → low). The results showed that the participants in the low → medium → high switch frequency group recovered faster from initially heightened systolic blood pressure when compared with participants in the high → medium → low group. It is concluded that the results point to a physiological "carry over" effect associated with beginning a task at rapid response switching frequency levels, and suggest the importance of habituation to task demands as a means of offsetting potentially unhealthy levels of reactivity. Implications for modern work environments are discussed.

Sustained release of the candidate antiretroviral peptides T-1249 and JNJ54310516-AFP from a rod insert vaginal ring

Administration of biomacromolecular drugs in effective quantities from conventional vaginal rings is hampered by poor drug permeability in the polymers from which rings are commonly constructed. Here, we report the formulation development and testing of rod insert rings for sustained release of the candidate antiretroviral peptides T-1249 and JNJ54310516-AFP (JNJ peptide), both of which have potential as HIV microbicides. Rod inserts were prepared comprising antiviral peptides T-1249 or JNJ peptide in combination with a hydrophilic excipient (sodium chloride, sodium glutamate, lactose or zinc acetate) dispersed at different loadings within a medical grade silicone elastomer. The inserts were tested for weight change and swelling when immersed in simulated vaginal fluid (SVF). Dye migration into the inserts was also assessed visually over 28 days. In vitro release of T-1249 and JNJ peptide from rings containing various insert types was tested. Weight change and degree of swelling of rods immersed in SVF was dependent on the type and concentration of excipient present. The rods displayed the following rank order in terms of weight change: sodium glutamate > zinc acetate ≈ sodium chloride > lactose. The weight change and degree of swelling of the inserts did not correlate with the level of dye uptake observed. In vitro release of T-1249 was improved through addition of lactose, sodium chloride and sodium glutamate, while release of JNJ peptide was improved through addition of sodium chloride or sodium glutamate. Sustained release of hydrophobic peptides can be achieved using a rod insert ring design formulated to include a hydrophilic excipient. Release rates were dependent upon the type of excipient used. The degree of release improvement with different inserts partially reflects their ability to imbibe surrounding fluid and swell in aqueous environments.