1,297 research outputs found
Preliminary report of the oil and gas possibilities between Pine and Cumberland Mountains, southeastern Kentucky
Elongate, low-amplitude flexures in strata of Pennsylvanian age have been delineated in recent mapping by the U. S. Geological Survey in coÂoperation with the Kentucky Geological Survey in a 600-square-mile (l ,536- square-kilometer) area between Pine and Cumberland Mountains in southÂeastern Kentucky. Cresta! culminations on gentle anticlinal folds may indicate loci of subsurface closures for entrapment of oil and gas. The area studied is underlain by more than 15,000 feet (4,500 meters) of Paleozoic strata containing potential source-beds, reservoirs, and cap rocks. Faults, unconformities, abrupt facies changes, and regional thickness variations enÂhance the geologic setting for possible oil and gas accumulations. Although the area is not producing oil and gas, shows were reported from each of seven exploratory test holes. Drilling depths to potential reservoirs ore modÂerate, and markets are relatively close and accessible.
The area between Pine and Cumberland Mountains is a composite structural basin, as the flat-lying Pine Mountain overthrust fault separates a deep sequence of lower Paleozoic marine strata from the overlying upper Paleozoic marine and nonmarine rocks. The gentle flexures in surface strata of Pennsylvanian age trend east-northeasterly, but the attitude, size, and shape of structures below the thrust fault are unknown. A possible northÂnorthwest interference pattern suggested by a series of axial culminations and depressions may reflect subthrust structural or paleogeomorphic alignÂments. Geophysical surveys or additional deep well control are necessary to provide data on the deep subsurface configuration
South Dakota Sex and Age Structure, 1980-1990
Age and sex structure of a population plays a critical role in determining the needs and lifestyle of that population. One community, for example, may have a high number of children and youth, a sure indicator of need for teachers and schools; another community may have a high proportion of elderly, indicating a greater need for medical services. People of different ages or gender also may have different consumer preferences. When business leaders and community leaders know the age and sex structure of their community, they can use that information to help direct resources toward meeting particular needs in education, housing, recreation, and medical and social services. Although no two communities are likely to have identical age and sex structures, there are general patterns that are helpful for identifying potential population needs. Population pyramids and indices are useful for illustrating these patterns
Resonant Phenomena in Antihydrogen-Hydrogen Scattering
We present a treatment of cold hydrogen-antihydrogen collisions based on the
asymptotic properties of atom-antiatom interactions. We derive general formulas
for the elastic and inelastic cross sections and for the scattering lengths and
analyze their sensitivity to the parameters characterizing the inelasticity of
the collision process. Given the inelasticity, we obtain bounds for the complex
scattering length. We investigate the influence of strong nuclear forces and
the isotope effects in and collisions
and demonstrate enhancement of these effects due to the presence of the
near-threshold narrow () states. The
values of the elastic and inelastic cross-sections with simultaneous account of
rearrangement and strong forces are presented. General expressions for the
(complex) energies of the near-threshold states are
obtained.Comment: 26 pages 7 figure
Phosphatidylinositol 3-kinase activation is required for insulin-stimulated sodium transport in A6 cells
Insulin stimulates amiloride-sensitive sodium transport in models of the distal nephron. Here we demonstrate that, in the A6 cell line, this action is mediated by the insulin receptor tyrosine kinase and that activation of phosphatidylinositol 3-kinase (PI 3-kinase) lies downstream of the receptor tyrosine kinase. Functionally, a specific inhibitor of PI 3-kinase, LY-294002, blocks basal as well as insulin-stimulated sodium transport in a dose-dependent manner (IC50 approximately 6 microM). Biochemically, PI 3-kinase is present in A6 cells and is inhibited both in vivo and in vitro by LY-294002. Furthermore, a subsequent potential downstream signaling element, pp70 S6 kinase, is activated in response to insulin but does not appear to be part of the pathway involved in insulin-stimulated sodium transport. Together with previous reports, these results suggest that insulin may induce the exocytotic insertion of sodium channels into the apical membrane of A6 cells in a PI 3-kinase-mediated manner
Skeletal Structural Basis of Density Banding in the Reef Coral Montastrea Annularis
Density banding in coral skeletons can provide for reconstruction of the coral\u27s growth en- vironment over long periods. The physical differ- ences between low and high density portions of a skeletal band are not well understood. The skeletal architecture of M. annularis from Southeast Flor- ida, the Florida Keys, St. Croix, the Bahamas, and Mexico was compared in X-ray revealed high den- sity (HD), low density (LD), and stress HD bands. Density changes arose from differences in the size, but not spacing, of exothecal structural elements (horizontal dissepiments and vertical costae). En- dothecal architecture size (e.g., columella, dissepi- ments, septa) was relatively constant between den- sity band types. Results have implications for studies of coral growth, sclerochronology, and iso- topic/trace element composition
Mouse cytotoxic T cell-derived granzyme B activates the mitochondrial cell death pathway in a bim-dependent fashion
Cytotoxic T cells (Tc) use perforin and granzyme B (gzmB) to kill virus-infected cells and cancer cells. Recent evidence suggests that human gzmB primarily induces apoptosis via the intrinsic mitochondrial pathway by either cleaving Bid or activating Bim leading to the activation of Bak/Bax and subsequent generation of active caspase-3. In contrast, mouse gzmB is thought to predominantly induce apoptosis by directly processing pro-caspase-3. However, in certain mouse cell types gzmB-mediated apoptosis mainly occurs via the mitochondrial pathway. To investigate whether Bim is involved under the latter conditions, we have now employed ex vivo virus-immune mouse Tc that selectively kill by using perforin and gzmB (gzmB+Tc) as effector cells and wild type as well as Bim- or Bak/Bax-deficient spontaneously (3T9) or virus-(SV40) transformed mouse embryonic fibroblast cells as targets. We show that gzmB+Tc-mediated apoptosis (phosphatidylserine translocation, mitochondrial depolarization, cytochrome c release, and caspase-3 activation) was severely reduced in 3T9 cells lacking either Bim or both Bak and Bax. This outcome was related to the ability of Tc cells to induce the degradation of Mcl-1 and Bcl-XL, the anti-apoptotic counterparts of Bim. In contrast, gzmB+Tc-mediated apoptosis was not affected in SV40-transformed mouse embryonic fibroblast cells lacking Bak/Bax. The data provide evidence that Bim participates in mouse gzmB+Tc-mediated apoptosis of certain targets by activating the mitochondrial pathway and suggest that the mode of cell death depends on the target cell. Our results suggest that the various molecular events leading to transformation and/or immortalization of cells have an impact on their relative resistance to the multiple gzmB+Tc-induced death pathways
Variational calculations for the hydrogen-antihydrogen system with a mass-scaled Born-Oppenheimer potential
The problem of proton-antiproton motion in the --
system is investigated by means of the variational method. We introduce a
modified nuclear interaction through mass-scaling of the Born-Oppenheimer
potential. This improved treatment of the interaction includes the nondivergent
part of the otherwise divergent adiabatic correction and shows the correct
threshold behavior.
Using this potential we calculate the vibrational energy levels with angular
momentum 0 and 1 and the corresponding nuclear wave functions, as well as the
S-wave scattering length. We obtain a full set of all bound states together
with a large number of discretized continuum states that might be utilized in
variational four-body calculations. The results of our calculations gives an
indication of resonance states in the hydrogen-antihydrogen system
Role of loop entropy in the force induced melting of DNA hairpin
Dynamics of a single stranded DNA, which can form a hairpin have been studied
in the constant force ensemble. Using Langevin dynamics simulations, we
obtained the force-temperature diagram, which differs from the theoretical
prediction based on the lattice model. Probability analysis of the extreme
bases of the stem revealed that at high temperature, the hairpin to coil
transition is entropy dominated and the loop contributes significantly in its
opening. However, at low temperature, the transition is force driven and the
hairpin opens from the stem side. It is shown that the elastic energy plays a
crucial role at high force. As a result, the phase diagram differs
significantly with the theoretical prediction.Comment: 9 pages, 8 figures; J. Chem. Phys (2011
Oceanic distribution of inorganic germanium relative to silicon: Germanium discrimination by diatoms
Seventeen inorganic germanium and silicon concentration profiles collected from the Atlantic, southwest Pacific, and Southern oceans are presented. A plot of germanium concentration versus silicon concentration produced a near-linear line with a slope of 0.760 × 10−6 (±0.004) and an intercept of 1.27 (±0.24) pmol L−1 (r2 = 0.993, p < 0.001). When the germanium-to-silicon ratios (Ge/Si) were plotted versus depth and/or silicon concentrations, higher values are observed in surface waters (low in silicon) and decreased with depth (high in silicon). Germanium-to-silicon ratios in diatoms (0.608–1.03 × 10−6) and coupled seawater samples (0.471–7.46 × 10−6) collected from the Southern Ocean are also presented and show clear evidence for Ge/Si fractionation between the water and opal phases. Using a 10 box model (based on PANDORA), Ge/Si fractionation was modeled using three assumptions: (1) no fractionation, (2) fractionation using a constant distribution coefficient (KD) between the water and solid phase, and (3) fractionation simulated using Michaelis-Menten uptake kinetics for germanium and silicon via the silicon uptake system. Model runs indicated that only Ge/Si fractionation based on differences in the Michaelis-Menten uptake kinetics for germanium and silicon can adequately describe the data. The model output using this fractionation process produced a near linear line with a slope of 0.76 × 10−6 and an intercept of 0.92 (±0.28) pmol L−1, thus reflecting the oceanic data set. This result indicates that Ge/Si fractionation in the global ocean occurs as a result of subtle differences in the uptake of germanium and silicon via diatoms in surface waters
Mcl-1 Is a Key Regulator of Apoptosis Resistance in Chlamydia trachomatis-Infected Cells
Chlamydia are obligate intracellular bacteria that cause variety of human diseases. Host cells infected with Chlamydia are protected against many different apoptotic stimuli. The induction of apoptosis resistance is thought to be an important immune escape mechanism allowing Chlamydia to replicate inside the host cell. Infection with C. trachomatis activates the Raf/MEK/ERK pathway and the PI3K/AKT pathway. Here we show that inhibition of these two pathways by chemical inhibitors sensitized C. trachomatis infected cells to granzyme B-mediated cell death. Infection leads to the Raf/MEK/ERK-mediated up-regulation and PI3K-dependent stabilization of the anti-apoptotic Bcl-2 family member Mcl-1. Consistently, interfering with Mcl-1 up-regulation sensitized infected cells for apoptosis induced via the TNF receptor, DNA damage, granzyme B and stress. Our data suggest that Mcl-1 up-regulation is primarily required to maintain apoptosis resistance in C. trachomatis-infected cells
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