9,006 research outputs found
Advanced expander test bed program
The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust. Contract work began 27 Apr. 1990. During 1992, a major milestone was achieved with the review of the final design of the oxidizer turbopump in Sep. 1992
First teuthid cephalopod from the Lower Jurassic of South America (Neuquén Basin, Argentina)
A new species of squid, Teudopsis jeletzkyi n. sp., is described from the Toarcian (Lower Jurassic) of the Los Molles Formation in Neuquen Province, central west Argentina. Fossil squids have thus far been unknown in the Mesozoic of South America. This species is the first record of the Order Teuthida in the Jurassic of South America
First teuthid cephalopod from the Lower Jurassic of South America (Neuquén Basin, Argentina)
A new species of squid, Teudopsis jeletzkyi n. sp., is described from the Toarcian (Lower Jurassic) of the Los Molles Formation in Neuquen Province, central west Argentina. Fossil squids have thus far been unknown in the Mesozoic of South America. This species is the first record of the Order Teuthida in the Jurassic of South America
Metal determination in organic fluids of patients with stainless steel hip arthroplasty.
In 20 stainless steel Charnley hip arthroplasties (with a follow-up of 10-13 years)
nickel, chromium and manganese levels were measured in blood, plasma and urine
by atomic absorption spectrophotometry. Skin patch tests for these metals, and
clinical and roentgenographic results of arthroplasty were also assessed.
Metal levels in organic fluids were plotted against a control population homogene-
ous for age, residence and anamnestic conditions with the first, but which had never
undergone a prosthesis or other metallic implant surgical procedure.
Nickel levels in blood, plasma and urine, manganese levels in blood and urine and
chromium levels in plasma were significantly higher in the hip prostheses popula-
tion.
Metal ion release from stainless steel prostheses is discussed with regard to implant
failure, metal sensitivity and carcinogenesis
Past and Present Forest Composition and Natural History of Deep Woods, Hocking County, Ohio
Author Institution: Department of Environmental and Plant Biology, Ohio UniversityDeep Woods, a 114-ha private preserve in Hocking County, OH, is the site of an all taxa biotic inventory (ATBI) coordinated by the Ohio Biological Survey. Here we describe the forest vegetation and natural history of the site and evaluate the role of human disturbance in structuring the regional landscape. Due to various abiotic factors, the area offers a diversity of habitats and species. The bedrock geology consists of sedimentary rock from the Mississippian and Pennsylvanian formations with alluvial deposits along a riparian corridor. At least three soil orders are represented: alfisols, inceptisols, and ultisols. As is typical of most of unglaciated Ohio, the forests here have been subjected to a long history of anthropogenic disturbance. The first inhabitants of the area were ancient moundbuilders (ca. 2500 YBP). During the 1700s, Shawnee and Delaware groups resided throughout the county. Anglo settlers drove all Native American groups out of the area by the early 1800s. The original land survey data (1801) suggested that the dominant vegetation at Deep Woods was composed of Quercus alba, Q. velutina, Carya spp., and Cornus florida (relative importance value, RIV = 34, 13, 12, 11%, respectively). Tax records show that Anglo-ownership of the property dates from the mid-1830s. County death records indicate occupations of 19th century landowners primarily as farmers. Dominant vegetation types include: hydric floodplain, mesic upland, and xeric ridgetop. Betula nigra, Carpinus caroliniana, Ulmus americana, andLiriodendron tulipifera (RIV = 16, 11, 11, 10%) dominate the floodplain. Whereas L. tulipifera, Acer saccharum, andB. alleghaniensis (RIV = 21, 15, 11%) and A rubrum, Q. prinus, and Q. alba (RIV= 27, 13, 9%) dominate the upland and ridgetop, respectively. Several other minor habitats also exist such as pasture fields, hemlock ravines, sandstone outcrops, and rockhouse formations. We conclude that the present species composition resembles the 1801 land survey, even though the post settlement disturbances were different than Native American disturbance regimes
Tripartite entanglement detection through tripartite quantum steering in one-sided and two-sided device-independent scenarios
In the present work, we study tripartite quantum steering of quantum
correlations arising from two local dichotomic measurements on each side in the
two types of partially device-independent scenarios: -sided
device-independent scenario where one of the parties performs untrusted
measurements while the other two parties perform trusted measurements and
-sided device-independent scenario where one of the parties performs trusted
measurements while the other two parties perform untrusted measurements. We
demonstrate that tripartite steering in the -sided device-independent
scenario is weaker than tripartite steering in the -sided device-independent
scenario by using two families of quantum correlations. That is these two
families of quantum correlations in the -sided device-independent framework
detect tripartite entanglement through tripartite steering for a larger region
than that in the -sided device-independent framework. It is shown that
tripartite steering in the -sided device-independent scenario implies the
presence of genuine tripartite entanglement of quantum
system, even if the correlation does not exhibit genuine nonlocality or genuine
steering.Comment: 14 pages, 4 figures, accepted for publication in Physical Review
Disentangling the Structure-Activity Relationships of Naphthalene Diimides as Anticancer G-Quadruplex-Targeting Drugs
In the context of developing efficient anticancer therapies aimed at eradicating any sort of tumors, G-quadruplexes
represent excellent targets. Small molecules able to interact with G-quadruplexes can interfere with cell pathways specific of tumors and common to all cancers. Naphthalene diimides (NDIs) are among the most promising, putative anticancer G-quadruplextargeting drugs, due to their ability to simultaneously target multiple G-quadruplexes and their strong, selective in vitro and in vivo anticancer activity. Here, all the available biophysical, biological, and structural data concerning NDIs targeting Gquadruplexes were systematically analyzed. Structure−activity correlations were obtained by analyzing biophysical data of their interactions with G-quadruplex targets and control duplex structures, in parallel to biological data concerning the antiproliferative activity of NDIs on cancer and normal cells. In addition, NDI binding modes to G-quadruplexes were discussed in consideration of the structures and properties of NDIs by in-depth analysis of the available structural models of G-quadruplex/NDI complexes
Intrahepatic persistent fetal right umbilical vein: a retrospective study
Introduction: To appraise the incidence and value of intrahepatic persistent right umbilical vein (PRUV). Methods: This was a single-center study. Records of all women with a prenatal diagnosis of intrahepatic PRUV were reviewed. The inclusion criteria were women with gestational age greater than 13 weeks of gestation. Exclusion criteria were fetuses with situs abnormalities, due to the hepatic venous ambiguity, and extrahepatic PRUV. The primary outcome was the incidence of intrahepatic PRUV in our cohort. The secondary outcomes were associated malformations. Results: 219/57,079 cases (0.38%) of intrahepatic PRUV were recorded. The mean gestational age at diagnosis was 21.8 ± 2.9 weeks of gestations. PRUV was isolated in the 76.7%, while in 23.3% was associated with other major or minor abnormalities. The most common associated abnormalities were cardiovascular abnormalities (8.7%), followed by genitourinary abnormalities (6.4%), skeletal abnormalities (4.6%), and central nervous system abnormalities (4.1%). Within the cardiovascular abnormalities, the most common one was ventricular septal defect (six cases). Conclusion: In most cases PRUV is an isolated finding. Associated minor or major malformations are presented in the 23.3% of the cases, so this finding should prompt detailed prenatal assessment of the fetus, with particular regard to cardiovascular system
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