Isotopic evidence for a terrestrial source of organic compounds found in martian meteorites Allan Hills 84001 and Elephant Moraine 79001

Stepped-heating experiments on martian meteorites Allan Hills 84001 (ALH84001) and Elephant Moraine 79001 (EETA79001) revealed low-temperature (200 to 430 degrees Celsius) fractions with a carbon isotopic composition delta13C between -22 and -33 per mil and a carbon-14 content that is 40 to 60 percent of that of modern terrestrial carbon, consistent with a terrestrial origin for most of the organic material. Intermediate-temperature (400 to 600 degrees Celsius) carbonate-rich fractions of ALH84001 have delta13C of +32 to +40 per mil with a low carbon-14 content, consistent with an extraterrestrial origin, whereas some of the carbonate fraction of EETA79001 is terrestrial. In addition, ALH84001 contains a small preterrestrial carbon component of unknown origin that combusts at intermediate temperatures. This component is likely a residual acid-insoluble carbonate or a more refractory organic phase.     

Interaction of the p53-regulated protein Gadd45 with proliferating cell nuclear antigen

GADD45 is a ubiquitously expressed mammalian gene that is induced by DNA damage and certain other stresses. Like another p53-regulated gene, p21WAF1/CIP1, whose product binds to cyclin-dependent kinases (Cdk's) and proliferating cell nuclear antigen (PCNA), GADD45 has been associated with growth suppression. Gadd45 was found to bind to PCNA, a normal component of Cdk complexes and a protein involved in DNA replication and repair. Gadd45 stimulated DNA excision repair in vitro and inhibited entry of cells into S phase. These results establish GADD45 as a link between the p53-dependent cell cycle checkpoint and DNA repair.     

The effect of furosemide on serum prolactin levels in the postpartum period

Furosemide, in combination with breast binding and milk fluid restriction, seems to inhibit postpartum lactation effectively, but has no effect in reducing serum prolactin levels. Inhibition of milk secretion must therefore be mediated by other mechanisms.     

Parboiling of rice. Part I: Effect of hot soaking time on quality of milled rice

This study investigated the effect of soaking time on the quality of parboiled rice. The paddy was soaked in water at 25 and 80 °C for 15, 30, 45, 60 and 120 min. The soaked paddy was steamed, dried, stored and milled. With increasing soaking time a significant increase in water absorption and milling and head rice yield (hence reduction in broken rice) was observed. A significant difference in milling yield, at the 1% level, was obtained between the raw rice control and the hot soaked parboiled samples. A large reduction in fissured grain was observed after soaking. It is suggested that parboiling fills the void spaces and cements the cracks inside the endosperm, making the grain harder and minimizing internal fissuring and thereby breakage during milling.     

Sulfidation behavior of Ni-Cr-Mo alloys at 700°C

The effect of molybdenum additions 5, 10, 15, and 20 wt. %, on the sulfidation behavior of Ni-20Cr, and the effect of chromium additions, 5, 10, 15, and 20 wt.%, on the sulfidation of Ni-20Mo were studied in pure sulfur vapor at 700°C. In general, the alloys followed a linear or near-linear rate law, the sulfidation rate of Ni-20Mo being slightly less than that of Ni-20Cr. The alloys having the lowest ternary addition, e.g., Ni-Cr-5Mo and Ni-20Mo-5Cr. exhibited the most rapid reaction rates. The highest alloying additions of 20 wt.% had no appreciable benefit on reaction rates. Scale structures were complex but generally consisted of several layers. The outer layer was always NiS_1.03, although both binaries formed Ni₃S₂ within the NiS_1.03. An inner layer of Cr₃S₄ existed in which there was considerable dissolved molybdenum. A thin, intermediate layer of Cr₂S₃ generally formed between the Cr₃S₄ and the outer nickel sulfide. An innermost layer of MoS₂ formed on all alloys containing more than 10 wt. % Mo, and a second phase of Mo₂S₃ formed within the MoS₂ on Ni-20Mo. Although the scales changed with alloy composition, no significant changes in reaction rate were observed. Notable differences in both scale structure and reaction kinetics between this study and previous studies were apparent. The differences and possible reaction mechanisms are discussed.     

Outcome measures for low back pain research. A proposal for standardized use

STUDY DESIGN: An international group of back pain researchers considered recommendations for standardized measures in clinical outcomes research in patients with back pain. OBJECTIVES: To promote more standardization of outcome measurement in clinical trials and other types of outcomes research, including meta-analyses, cost-effectiveness analyses, and multicenter studies. SUMMARY OF BACKGROUND DATA: Better standardization of outcome measurement would facilitate comparison of results among studies, and more complete reporting of relevant outcomes. Because back pain is rarely fatal or completely cured, outcome assessment is complex and involves multiple dimensions. These include symptoms, function, general well-being, work disability, and satisfaction with care. METHODS: The panel considered several factors in recommending a standard battery of outcome measures. These included reliability, validity, responsiveness, and practicality of the measures. In addition, compatibility with widely used and promoted batteries such, as the American Academy of Orthopaedic Surgeons Lumbar Cluster were considered to minimize the need for changes when these instruments are used. RESULTS: First, a six-item set was proposed, which is sufficiently brief that it could be used in routine care settings for quality improvement and for research purposes. An expanded outcome set, which would provide more precise measurement for research purposes, includes measures of severity and frequency of symptoms, either the Roland or the Oswestry Disability Scale, either the SF-12 or the EuroQol measure of general health status, a question about satisfaction with symptoms, three types of "disability days," and an optional single item on overall satisfaction with medical care. CONCLUSION: Standardized measurement of outcomes would facilitate scientific advances in clinical care. A short, 6-item questionnaire and a somewhat expanded, more precise battery of questionnaires can be recommended. Although many considerations support such recommendations, more data on responsiveness and the minimally important change in scores are needed for most of the instruments.     

Molecular and cytogenetic analyses of stably and unstably expressed transgene loci in tobacco

To study the influence of genomic context on transgene expression, we have determined the T-DNA structure, flanking DNA sequences, and chromosomal location of four independent transgene loci in tobacco. Two of these loci were stably expressed in the homozygous condition over many generations, whereas the other two loci became unstable after several generations of homozygosity. The stably expressed loci comprised relatively simple T-DNA arrangements that were flanked on at least one side by plant DNA containing AT-rich regions that bind to nuclear matrices in vitro. Of the unstably expressed loci, one consisted of multiple incomplete T-DNA copies, and the second contained a single intact T-DNA; in both cases, however, binary vector sequences were directly contiguous to a right T-DNA border. Fluorescence in situ hybridization demonstrated that the two stably expressed inserts were present in the vicinity of telomeres. The two unstably expressed inserts occupied intercalary and paracentromeric locations, respectively. Results on the stability of transgene expression in F1 progeny obtained by intercrossing the four lines and the sensitivity of the four transgene loci to inactivation in the presence of an unlinked "trans-silencing" locus are also presented. The findings are discussed in the context of repetitive DNA sequences and the allotetraploid nature of the tobacco genome.