Corrosion-Resistant Steel Reinforcing Bars Initial Test

The initial portion of the first phase of a five phase research effort to evaluate a corrosionresistant steel for reinforcing bars is descnoed. Rapid corrosion potential and time-to-corrosion (macrocell) tests are used. The test specimen consists of a No. 5 reinforcing bar embedded in a 30 mm diameter, 102 nnn long cylinder of mortar. The mortar is made using portland cement, graded Ottawa sand, and deionized water. Four different steel types are evaluated: hot-rolled regular steel, Thermex treated (quenched and tempered) regular steel, hot-rolled corrosion resistant steel, and Thermex treated corrosion resistant steeL Corrosion potential tests are perlbrmed to determine the tendency of a steel to corrode. The results for these tests are fuirly consistent, with little scatter. There is no significant difference in potentials for the four steels. The use of different test solutions did not influence the potential of the four steels. The macrocell tests are perlbrmed to determine the time-to-corrosion and the corrosion rates. The results for some of these tests are not consistent and show considerable scatter. The macrocell test is sensitive to the quality in the specimen fabrication. Because the initial tests in Phase I did not perform as intended, it is difficult to determine for certain which steel has the best corrosion resistance based on the resUlts reported here. However, the hot rolled regular steel specimens consistently exluoit the highest corrosion rate. The test solutions used at the anode and cathode in the macrocell tests appear to influence the corrosion rate and the difference in rates between the four steels. When the difference in pH of the anode and cathode solutions is decreased, the corrosion rates are reduced and the difference between the rates for the four steels is more pronounced. Based on the results of the Phase I initial tests, some modifications to the specimen fabrication procedure are reconnnended. The epoxy band should be applied in two coats. The reinforcing bar lengths should be heated after cleaning and after applying each coat in order to improve the bond between the reinforcing bar and the first epoxy coat as well as between the two coats of epoxy. Special care should be exercised when applying the epoxy band. Addition work in Phase I includes an evaluation of the effects of changing the ratio of the number of cathode to anode specimens from 3:3 to 2:1. Special care should also be exercised in the oversight of the corrosion potential and macrocell tests

Monitoring for Renal Stone Recurrence in Astronauts With History of Stone

After an initial stone episode persons are at increased risk for future stone formation. A systematic approach is required to monitor the efficacy of treatment and preventive measures, and to assess the risk of developing new stones. This is important for persons working in critical jobs or austere environments, such as astronauts. A literature review of the current standards of care for renal stone monitoring and imaging was done. Military and civil aviation standards were also reviewed, as well as the medical precedents from the space program. Additionally, a new, more effective, renal stone ultrasound protocol has been developed. Using this work, a monitoring algorithm was proposed that takes into consideration the unique mission and operational environment of spaceflight. The approach to imaging persons with history of renal stones varies widely in the literature. Imaging is often done yearly or biannually, which may be too long for mission critical personnel. In the proposed algorithm astronauts with a history of renal stone, who may be under consideration for assignment, are imaged by a detailed, physiciandriven, ultrasound protocol. Unassigned personnel are monitored by yearly ultrasound and urine studies. Any positive ultrasound study is then followed by low-dose renal computed tomography scan. Other criteria are also established. The proposed algorithm provides a balanced approach between efficacy and reduced radiation exposure for the monitoring of astronauts with a renal stone history. This may eventually allow a transition from a risk-averse, to a risk-modifying approach that can enable continued service of individuals with history of renal stone that have adequately controlled risk factors

The very large G-protein coupled receptor VLGR1: a component of the ankle link complex required for the normal development of auditory hair bundles

Sensory hair bundles in the inner ear are composed of stereocilia that can be interconnected by a variety of different link types, including tip links, horizontal top connectors, shaft connectors, and ankle links. The ankle link antigen is an epitope specifically associated with ankle links and the calycal processes of photoreceptors in chicks. Mass spectrometry and immunoblotting were used to identify this antigen as the avian ortholog of the very large G-protein-coupled receptor VLGR1, the product of the Usher syndrome USH2C (Mass1) locus. Like ankle links, Vlgr1 is expressed transiently around the base of developing hair bundles in mice. Ankle links fail to form in the cochleae of mice carrying a targeted mutation in Vlgr1 (Vlgr1/del7TM), and the bundles become disorganized just after birth. FM1-43 [N-(3-triethylammonium)propyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] dye loading and whole-cell recordings indicate mechanotransduction is impaired in cochlear, but not vestibular, hair cells of early postnatal Vlgr1/del7TM mutant mice. Auditory brainstem recordings and distortion product measurements indicate that these mice are severely deaf by the third week of life. Hair cells from the basal half of the cochlea are lost in 2-month-old Vlgr1/del7TM mice, and retinal function is mildly abnormal in aged mutants. Our results indicate that Vlgr1 is required for formation of the ankle link complex and the normal development of cochlear hair bundles

Visual-olfactory integration in the human disease vector mosquito, Aedes aegypti

Mosquitoes rely on the integration of multiple sensory cues, including olfactory, visual, and thermal stimuli, to detect, identify, and locate their hosts [1, 2, 3, 4]. Although we increasingly know more about the role of chemosensory behaviors in mediating mosquito-host interactions [1], the role of visual cues is comparatively less studied [3], and how the combination of olfactory and visual information is integrated in the mosquito brain remains unknown. In the present study, we used a tethered-flight light-emitting diode (LED) arena, which allowed for quantitative control over the stimuli, and a control theoretic model to show that CO_2 modulates mosquito steering responses toward vertical bars. To gain insight into the neural basis of this olfactory and visual coupling, we conducted two-photon microscopy experiments in a new GCaMP6s-expressing mosquito line. Imaging revealed that neuropil regions within the lobula exhibited strong responses to objects, such as a bar, but showed little response to a large-field motion. Approximately 20% of the lobula neuropil we imaged were modulated when CO2 preceded the presentation of a moving bar. By contrast, responses in the antennal (olfactory) lobe were not modulated by visual stimuli presented before or after an olfactory stimulus. Together, our results suggest that asymmetric coupling between these sensory systems provides enhanced steering responses to discrete objects