Triaxial digital fluxgate magnetometer for NASA applications explorer mission: Results of tests of critical elements

Tests performed to prove the critical elements of the triaxial digital fluxgate magnetometer design were described. A method for improving the linearity of the analog to digital converter portion of the instrument was studied in detail. A sawtooth waveform was added to the signal being measured before the A/D conversion, and averaging the digital readings over one cycle of the sawtooth. It was intended to reduce bit error nonlinearities present in the A/D converter which could be expected to be as much as 16 gamma if not reduced. No such nonlinearities were detected in the output of the instrument which included the feature designed to reduce these nonlinearities. However, a small scale nonlinearity of plus or minus 2 gamma with a 64 gamma repetition rate was observed in the unit tested. A design improvement intended to eliminate this small scale nonlinearity was examined

Morphological Variation in Three-Dimensional Printed Replicas

Employed primarily for outreach and education, the three-dimensional (3D) printer used in this analysis provides a means of producing tangible models of fragile and restricted-use specimens for students from a wide variety of disciplines, and is used here to produce prints associated with historic and prehistoric cultural objects. Recognizing that inconsistencies occur in 3D prints due to environmental variables, this exploratory effort was aimed at identifying the geometry that deviates most from the original scan data. A total of five replicas were printed then compared by calculating the gap distance between the nominal (original scan data) and measured data (scan of 3D printed replica) in Geomagic Control X. Results indicate that computer-aided inspection may prove useful in the refinement of 3D printing work flows, finishing, and the iterative refinement of 3D printer settings for specific real-world education- and outreach-based endeavors

Development of methods for the detection of trace amounts of selected carcinogenic and mutagenic amines in water

A great deal of concern exists over the presence of potentially carcinogenic and/or mutagenic substances in drinking water supplies. The general analytical schemes currently applied to water are less suited than specific methods for the detection of certain classes of organic contaminants such as aromatic amines because of their reactivity. We have concentrated our efforts at developing analytical schemes by which we are able to reliably detect, separate, and quantitate trace levels of a number of aromatic and heterocyclic amines. Both liquid and gas chromatographic methods have been developed. The relative strengths and limitations of the methods are discussed. Field evaluations of the final methods were carried out and reported.U.S. Department of the InteriorU.S. Geological SurveyOpe

R-h-erythropoietin counteracts the inhibition of in vitro erythropoiesis by tumour necrosis factor alpha in patients with rheumatoid arthritis

Anaemia of chronic disease (ACD) is a common extra-articular manifestation of rheumatoid arthritis (RA). Tumour necrosis factor alpha (TNFα) plays an important role in the development of ACD. The objective of the present study was to assess inhibition of in vitro colony-forming unit erythrocyte (CFUe) and blast-forming unit erythrocyte (BFUe) growth by TNFα and to examine whether this suppression could be counteracted by adding increasing concentrations of recombinant human erythropoietin (EPO) (r-h-EPO) to bone marrow cultures of RA patients with ACD and without anaemia (controls). Bone marrow cells of RA patients with ACD and control patients were cultured. The cultures were incubated with increasing concentrations of r-h-EPO (0.25; 0.5; 1; 2 U/ml), each in combination with increasing quantities of TFNα (0; 50; 100; 200; 400 U/ml). CFUe and BFUe were assessed after 7 and 14 days, respectively. Dose-dependent inhibition of BFUe and CFUc by increasing concentrations of TNFα was observed in ACD and controls. Regarding CFUe (ACD patients) incubated with 0.25 U/ml EPO, 50 U/ml TNFα caused 28% suppression compared to cultures without TNFα. Increasing the concentration of r-h-EPO from 0.25 U/ml to 2 U/ml completely restored the number of CFUe. A similar pattern was observed in BFUe growth in both groups. These data demonstrated the suppressive effects of TNFα on erythropoiesis in vitro and that the suppresed erythropoiesis could be partly corrected by the addition of excess r-h-EPO to the cultures. No significant differences were observed between ACD and control RA patients. This in vitro model may help explain the clinical response to r-h-EPO therapy as documented in RA patients with ACD

Accessibility of antiretroviral therapy in Ghana: Convenience of access

The convenience of accessing antiretroviral therapy (ART) is important for initial access to care and subsequent adherence to ART. We conducted a qualitative study of people living with HIV/AIDS (PLWHA) and ART healthcare providers in Ghana in 2005. The objective of this study was to explore the participants’ perceived convenience of accessing ART by PLWHA in Ghana. The convenience of accessing ART was evaluated from the reported travel and waiting times to receive care, the availability, orotherwise, of special considerations, with respect to the waiting time to receive care, for those PLWHA who were in active employment in the formal sector, the frequency of clinic visits before and after initiating ART, and whether the PLWHA saw the same or different providers at each clinic visit (continuity of care). This qualitative study used in-depth interviews based on Yin’s case-study research design to collect data from 20 PLWHA and 24 ART healthcare providers as study participants. . Reported travel time to receive ART services ranged from 2 to 12 h for 30% of the PLWHA.. Waiting time to receive care was from 4 to 9 h. . While known government workers, such as teachers, were attended to earlier in some of the centres, this was not a consistent practice in all the four ART centres studied. . The PLWHA corroborated the providers’ description of the procedure for initiating and monitoring ART in Ghana. . PLWHA did not see the same provider every time, but they were assured that this did not compromise the continuity of their care. Our study suggests that convenience of accessing ART is important to both PLWHA and ART healthcare providers, but the participants alluded to other factors, including open provider–patient communication, which might explain the PLWHA’sunderstanding of the constraints under which they were receiving care. The current nation-wide coverage of the ART programme in Ghana, however, calls for the replication of this study to identify possible perception changes over time that may need attention. Our study findings can inform interventions to promote access to ART, especially in Africa