Benefits of Spacecraft Level Vibration Testing

NASA-HDBK-7008 Spacecraft Level Dynamic Environments Testing discusses the approaches, benefits, dangers, and recommended practices for spacecraft level dynamic environments testing, including vibration testing. This paper discusses in additional detail the benefits and actual experiences of vibration testing spacecraft for NASA Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL) flight projects. JPL and GSFC have both similarities and differences in their spacecraft level vibration test approach: JPL uses a random vibration input and a frequency range usually starting at 5 Hz and extending to as high as 250 Hz. GSFC uses a sine sweep vibration input and a frequency range usually starting at 5 Hz and extending only to the limits of the coupled loads analysis (typically 50 to 60 Hz). However, both JPL and GSFC use force limiting to realistically notch spacecraft resonances and response (acceleration) limiting as necessary to protect spacecraft structure and hardware from exceeding design strength capabilities. Despite GSFC and JPL differences in spacecraft level vibration test approaches, both have uncovered a significant number of spacecraft design and workmanship anomalies in vibration tests. This paper will give an overview of JPL and GSFC spacecraft vibration testing approaches and provide a detailed description of spacecraft anomalies revealed

Improved DNA Electrophoresis in Conditions Favoring Polyborates and Lewis Acid Complexation

Spatial compression among the longer DNA fragments occurs during DNA electrophoresis in agarose and non-agarose gels when using certain ions in the conductive buffer, impairing the range of fragment sizes resolved well in a single gel. Substitutions using various polyhydroxyl anions supported the underlying phenomenon as the complexation of Lewis acids to DNA. We saw significant improvements using conditions (lithium borate 10 mM cations, pH 6.5) favoring the formation of borate polyanions and having lower conductance and Joule heating, delayed electrolyte exhaustion, faster electrophoretic run-speed, and sharper separation of DNA bands from 100bp to 12 kb in a single run

LOCAL IgA-MEMORY RESPONSE TO BACTERIAL ANTIGENS *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72248/1/j.1749-6632.1983.tb26912.x.pd

Does tumorigenesis select for or against mutations of the DNA repair-associated genes BRCA2 and MRE11?: Considerations from somatic mutations in microsatellite unstable (MSI) gastrointestinal cancers

BACKGROUND: The BRCA2 and MRE11 proteins participate in the repair of double-strand DNA breaks by homologous recombination. Germline BRCA2 mutations predispose to ovarian, breast and pancreatic cancer, while a germline MRE11 mutation is associated with an ataxia telangiectasia-like disorder. Somatic mutations of BRCA2 are rare in typical sporadic cancers. In tumors having microsatellite instability (MSI), somatic truncating mutations in a poly [A] tract of BRCA2 are reported on occasion. RESULTS: We analyzed gastrointestinal MSI cancers by whole gene BRCA2 sequencing, finding heterozygous truncating mutations in seven (47%) of 15 patients. There was no cellular functional defect in RAD51 focus-formation in three heterozygously mutated lines studied, although other potential functions of the BRCA2 protein could still be affected. A prior report of mutations in primary MSI tumors affecting the IVS5-(5–15) poly [T] tract of the MRE11 gene was confirmed and extended by analysis of the genomic sequence and protein expression in MSI cancer cell lines. Statistical analysis of the published MRE11 mutation rate in MSI tumors did not provide evidence for a selective pressure favoring biallelic mutations at this repeat. CONCLUSION: Perhaps conflicting with common suspicions, the data are not compatible with selective pressures during tumorigenesis promoting the functional loss of BRCA2 and MRE11 in MSI tumors. Instead, these data fit closely with an absence of selective pressures acting on BRCA2 and MRE11 gene status during tumorigenesis

Prediction of Spacecraft Vibration using Acceleration and Force Envelopes

The base forces in the GLAST X- and Z-axis sine vibration tests were similar to those derived using generic inputs (from users guide and handbook), but the base forces in the sine test were generally greater than the flight data. Basedrive analyses using envelopes of flight acceleration data provided more accurate predictions of the base force than generic inputs, and as expected, using envelopes of both the flight acceleration and force provided even more accurate predictions The GLAST spacecraft interface accelerations and forces measured during the MECO transient were relatively low in the 60 to 150 Hz regime. One may expect the flight forces measured at the base of various spacecraft to be more dependent on the mass, frequencies, etc. of the spacecraft than are the corresponding interface acceleration data, which may depend more on the launch vehicle configuration

Campylobacter pylori in Patients with Dyspeptic Symptoms and Endoscopic Evidence of Erosion(s)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73797/1/j.1572-0241.1989.tb02609.x.pd

The relationship between the insulin-like growth factor-1 axis, weight loss, an inflammation-based score and survival in patients with inoperable non-small cell lung cancer

<b>Background & aims:</b> The involvement of a systemic inflammatory response, as evidenced by the Glasgow Prognostic Score (GPS), is associated with weight loss and poor outcome in patients with non-small cell lung cancer. There is good evidence that nutritional and functional decline in patients with advanced malignant disease is associated with catabolic changes in metabolism. However, defects in anabolism may also contribute towards nutritional decline in patients with cancer. The aim of the present study was to examine the relationship between IGF-1 and IGFBP-3, performance status, mGPS and survival in patients with inoperable NSCLC. <b>Methods:</b> 56 patients with inoperable NSCLC were studied. The plasma concentrations of IGF-1, IGFBP-3 and leptin were measured using ELISA and RIA. <b>Results:</b> The patients were predominantly male (61%), over 60 years old (80%), with advanced (stage III or IV) disease (98%), with a BMI≥20 (84%), an ECOG-ps of 0 or 1 (79%), a haemoglobin (59%) and white cell count (79%) in the reference range. On follow-up 43 patients died of their cancer. On univariate analysis, BMI (p<0.05), Stage (p<0.05), ECOG-ps (p<0.05), haemoglobin (p<0.05), white cell count (p<0.05) and mGPS (p<0.05) were associated with cancer specific survival. There was no association between age, sex, treatment, IGF-1, IGFBP-3, IGF-1:IGFBP-3 ratio, or leptin and cancer specific survival. With an increasing mGPS concentrations of haemoglobin (p<0.005) and IGFBP-3 (p<0.05) decreased. mGPS was not associated with either IGF-1(p>0.20), or leptin (p>0.20). <b>Conclusions:</b> In summary, the results of this study suggest that anabolism (IGF-1 axis) does not play a significant role in the relationship between nutritional and functional decline, systemic inflammation and poor survival in patients with inoperable NSCLC