Correlation of stress-wave-emission characteristics with fracture in aluminum alloys, 1 September - 1 December 1969

Cryogenic testing of aluminum alloy specimens for fracture toughness and stress wave dat

An Efficient Strategy for the Synthesis of α,α′-cis and trans-Disubstituted Medium Ring Ethers

An asymmetric alkylation-ring-closing metathesis strat-egy was developed for the construction of a,a'-disubstituted medi-um ring ethers. The approach features an asymmetric alkylation of highly functionalized a-alkoxy acyl oxazolidinones followed by ring closure effected by Grubbs' ruthenium catalyst. The relation-ship between diene conformation and the rate of ring-closure was examined. Medium ring ethers are a common structural feature of many ladder ether marine toxins, as well as simpler me-tabolites from Laurencia species. This diverse collection of natural products often contains seven, eight, and nine membered ring ethers. 1 The challenge of efficient con-struction of medium ring ethers has led to the develop-ment of numerous strategies for their synthesis. 2-5 The vast majority of these approaches have focused on the a,a'-cis-disubstitution pattern rather than a,a'-trans-di-substituted medium ring ethers, despite their similar fre-quency of occurrence. trans-Isoprelaurefucin (1), 6 isolau-refucin methyl ether (2), 7 chlorofucin (3), 8 bromofucin (4), 9 isolaureatin (5), 10 and obtusenyne (6), 8 for example, all contain a,a'-trans-disubstituted medium ring ethers (Figure 1). Murai's synthesis of obtusenyne (6) 11 and our own recent syntheses of prelaureatin and laurallene 12 con-stitute the only known syntheses of medium ring ether natural products with the a,a'-trans-disubstitution ar-rangement. The investigation of a versatile, general strat-egy for the synthesis of both a,a'-cis and a,a'-trans-disubstituted medium ring ethers is described here. We recently published a total synthesis of the marine nat-ural product (+)-laurencin (9), in which the key steps were an asymmetric alkylation of the sodium enolate of substi-tuted acyl oxazolidinone 7, followed by ring-closing met-athesis of the resultant diene to give cyclic ether 8 (Scheme 1). 2 Previous work in our laboratory has demon-strated that an asymmetric aldol-ring-closing metathesis strategy for the assembly of medium ring ethers was equally adaptable to both the a,a'-cis and a,a'-trans-di-substituted medium ring ethers. 3,12 The asymmetric alky-lation-ring-closing metathesis approach to cyclic ethers also offered the potential for a similar adaptable strategy

Psychosocial Factors Associated with Longevity in the United States: Age Differences between the Old and Oldest-Old in the Health and Retirement Study

Recent growth in the number of adults surviving to advanced ages raises questions about the quality of life associated with increased longevity. Psychosocial factors have received relatively little attention in research on quality of life among the oldest-old. This study uses nationally representative data on older US adults to examine how social relationships, feelings of loneliness, and satisfaction with life and the aging experience differ between the oldest-old, those who have survived to age 90 or older, and older adults in their 70s. We find that the oldest-old are able to maintain social relationships with family and friends and receive more social support than younger elderly adults. Yet, the oldest-old are more likely to feel lonely due to their greater rates of widowhood. Satisfaction with life was higher among the oldest-old, but the oldest-old had more negative perceptions of the aging experience. Psychosocial dimensions of longevity should be considered in research on quality of life among the oldest-old

Monitoring of crack growth in Ti-Al-4v alloy by the stress wave analysis technique

Stress wave analysis techniques for monitoring crack growth in Ti-6Al-4V alloy pressure vessel wall

Oral health problems and mortality

AbstractBackground/purposePrevious studies have shown the relationship between individual oral health conditions and mortality; however, the relationship between mortality and multiple oral health conditions has not been examined. This study investigates the link between individual oral health problems and oral comorbidity and mortality risk.Materials and methodsData are derived from the National Health and Nutrition Examination Survey 1999–2004, which is linked to the National Death Index for mortality follow-up through 2006. We estimated the risk of mortality among people with three individual oral health conditions—tooth loss, root caries, and periodontitis as well as with oral comorbidity—or having all three conditions.ResultsSignificant tooth loss, root caries, and periodontal disease were associated with increased odds of dying. The relationship between oral health conditions and mortality disappeared when controlling for sociodemographic, health, and/or health behavioral indicators. Having multiple oral health problems was associated with an even higher rate of mortality.ConclusionIndividual oral health conditions—tooth loss, root caries, and periodontal disease—were not related to mortality when sociodemographic, health, and/or health behavioral factors were considered, and there was no differential pattern between the three conditions. Multiple oral health problems were associated with a higher risk of dying

From principles to action: Applying the National Research Council's principles for effective decision support to the Federal Emergency Management Agency's watch office

AbstractThe National Research Council (NRC) proposed six principles for effective decision support in its 2009 report Informing Decisions in a Changing Climate. We structured a collaborative project between the Federal Emergency Management Agency Region R9 (FEMA R9), the Western Region Headquarters of the National Weather Service (WR-NWS), and the Climate Assessment of the Southwest (CLIMAS) at the University of Arizona around the application of the NRC principles. The goal of the project was to provide FEMA R9's Watch Office with climate information scaled to their temporal and spatial interests to aid them in assessing the potential risk of flood disasters. We found that we needed specific strategies and activities in order to apply the principles effectively. By using a set of established collaborative research approaches we were better able to assess FEMA R9's information needs and WR-NWS's capacity to meet those needs. Despite our diligent planning of engagement strategies, we still encountered some barriers to transitioning our decision support tool from research to operations. This paper describes our methods for planning and executing a three-party collaborative effort to provide climate services, the decision support tool developed through this process, and the lessons we will take from this deliberate collaborative process to our future work and implications of the NRC principles for the broader field of climate services

Enantioselective Total Synthesis of Spirofungins A and B

The enantioselective total synthesis of spirofungins A (1) and B (2) is reported in 14 steps over the longest linear sequence. Key steps include the use of thiazolidinethione mediated aldol reactions to assemble the major fragments and installation of the C1–C6 side chain using a cross metathesis reaction

A new approach to generating research-quality data through citizen science: The USA National Phenology Monitoring System

Phenology is one of the most sensitive biological responses to climate change, and recent changes in phenology have the potential to shake up ecosystems. In some cases, it appears they already are. Thus, for ecological reasons it is critical that we improve our understanding of species’ phenologies and how these phenologies are responding to recent, rapid climate change. Phenological events like flowering and bird migrations are easy to observe, culturally important, and, at a fundamental level, naturally inspire human curiosity— thus providing an excellent opportunity to engage citizen scientists. The USA National Phenology Network has recently initiated a national effort to encourage people at different levels of expertise—from backyard naturalists to professional scientists—to observe phenological events and contribute to a national database that will be used to greatly improve our understanding of spatio-temporal variation in phenology and associated phenological responses to climate change.

Traditional phenological observation protocols identify specific dates at which individual phenological events are observed. The scientific usefulness of long-term phenological observations could be improved with a more carefully structured protocol. At the USA-NPN we have developed a new approach that directs observers to record each day that they observe an individual plant, and to assess and report the state of specific life stages (or phenophases) as occurring or not occurring on that plant for each observation date. Evaluation is phrased in terms of simple, easy-to-understand, questions (e.g. “Do you see open flowers?”), which makes it very appropriate for a citizen science audience. From this method, a rich dataset of phenological metrics can be extracted, including the duration of a phenophase (e.g. open flowers), the beginning and end points of a phenophase (e.g. traditional phenological events such as first flower and last flower), multiple distinct occurrences of phenophases within a single growing season (e.g multiple flowering events, common in drought-prone regions), as well as quantification of sampling frequency and observational uncertainties. These features greatly enhance the utility of the resulting data for statistical analyses addressing questions such as how phenological events vary in time and space, and in response to global change. This new protocol is an important step forward, and its widespread adoption will increase the scientific value of data collected by citizen scientists.
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Inflammatory Gene Variants in the Tsimane, An Indigenous Bolivian Population With a High Infectious Load

The Tsimane of lowland Bolivia are an indigenous forager-farmer population living under conditions resembling pre-industrial European populations, with high infectious morbidity, high infection and inflammation, and shortened life expectancy. Analysis of 917 persons ages 5 to 60+ showed that allele frequencies of 9 SNPs examined in the apolipoprotein E (apoE), C-reactive protein (CRP), and interleukin-6 (IL-6) genes differed from some European, African, and north Asian-derived populations. The apoE2 allele was absent, whereas four SNPs related to CRP and IL-6 were monomorphic: CRP (rs1800947, rs3093061, and rs3093062) and IL-6 (rs1800795). No significant differences in apoE, CRP, and IL-6 variants across age were found CRP levels were higher in carriers of two CRP proinflammatory SNPs, whereas they were lower in carriers of apoE4. Taken together, the evidence for (1) different allele frequencies between the Tsimane and other populations and (2) the correlations of CRP and apoE alleles with blood CRP may suggest that these variants are under selection in response to a high infection environment

Synthesis of (-)-Mucocin

An enantioselective total synthesis of (−)-mucocin has been completed. A combination of asymmetric glycolate aldol additions and ring closing metathesis reactions were exploited to construct the C18−C34 and C7−C17 fragments. A selective cross-metathesis reaction was employed as the key step to couple two complex fragments