1,590 research outputs found
Effects of fluoxetine on the oral environment of bulimics
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73809/1/j.1399-302X.1993.tb00545.x.pd
Anomalous thermal expansion in 1D transition-metal cyanides: what makes the novel trimetallic cyanide Cu1/3Ag1/3Au1/3CN behave differently?
The structural dynamics of a quasi-one-dimensional (1D) mixed-metal cyanide, Cu1/3Ag1/3Au1/3CN, with intriguing thermal properties is explored. All the current known related compounds with straight-chain structures, such as group 11 cyanides CuCN, AgCN, AuCN and bimetallic cyanides MxMâ1-xCN (M, Mâ = Cu, Ag, Au), exhibit 1D negative thermal expansion (NTE) along the chains and positive thermal expansion (PTE) perpendicular to them. Cu1/3Ag1/3Au1/3CN exhibits similar PTE perpendicular to the chains, however PTE, rather than NTE, is also observed along the chains. In order to understand the origin of this unexpected behavior, inelastic neutron scattering (INS) measurements were carried out, underpinned by lattice-dynamical density-functional-theory (DFT) calculations. Synchrotron-based pair-distribution-function (PDF) analysis and 13C solid-state nuclear-magnetic-resonance (SSNMR) measurements were also performed to build an input structural model for the lattice dynamical study. The results indicate that transverse motions of the metal ions are responsible for the PTE perpendicular to the chains, as is the case for the related group 11 cyanides. However NTE along the chain due to the tension effect of these transverse motions is not observed. As there are different metal-to-cyanide bond lengths in Cu1/3Ag1/3Au1/3CN, the metals in neighboring chains cannot all be truly co-planar in a straight-chain model. For this system, DFT-based phonon calculations predict small PTE along the chain due to low-energy chain-slipping modes induced by a bond-rotation effect on the weak metallophilic bonds. However the observed PTE is greater than that predicted with the straight-chain model. Small bends in the chain to accommodate truly co-planar metals provide an alternative explanation for thermal behavior. These would mitigate the tension effect induced by the transverse motions of the metals and, as temperature increases and the chains move further apart, a straightening could occur resulting in the observed PTE. This hypothesis is further supported by unusual evolution in the phonon spectra, which suggest small changes in local symmetry with temperature
The Reddening-Free Decline Rate Versus Luminosity Relationship for Type Ia Supernovae
We develop a method for estimating the host galaxy dust extinction for type
Ia supernovae based on an observational coincidence first noted by Lira (1995),
who found that the B-V evolution during the period from 30-90 days after V
maximum is remarkably similar for all events, regardless of light curve shape.
This fact is used to calibrate the dependence of the B(max)-V(max) and
V(max)-I(max) colors on the light curve decline rate parameter delta-m15, which
can, in turn, be used to separately estimate the host galaxy extinction. Using
these methods to eliminate the effects of reddening, we reexamine the
functional form of the decline rate versus luminosity relationship and provide
an updated estimate of the Hubble constant of Ho = 63.3 +- 2.2(internal) +-
3.5(external) km/s/Mpc.Comment: 32 pages, 10 figures, AJ 1999 in pres
Serine / threonine protein phosphatase 5 (PP5) participates in the regulation of glucocorticoid receptor nucleocytoplasmic shuttling
BACKGROUND: In most cells glucocorticoid receptors (GR) reside predominately in the cytoplasm. Upon hormone binding, the GR translocates into the nucleus, where the hormone-activated GR-complex regulates the transcription of GR-responsive genes. Serine/threonine protein phosphatase type 5 (PP5) associates with the GR-heat-shock protein-90 complex, and the suppression of PP5 expression with ISIS 15534 stimulates the activity of GR-responsive reporter plasmids, without affecting the binding of hormone to the GR. RESULTS: To further characterize the mechanism by which PP5 affects GR-induced gene expression, we employed immunofluorescence microscopy to track the movement of a GR-green fluorescent fusion protein (GR-GFP) that retained hormone binding, nuclear translocation activity and specific DNA binding activity, but is incapable of transactivation. In the absence of glucocorticoids, GR-GFP localized mainly in the cytoplasm. Treatment with dexamethasone results in the efficient translocation of GR-GFPs into the nucleus. The nuclear accumulation of GR-GFP, without the addition of glucocorticoids, was also observed when the expression of PP5 was suppressed by treatment with ISIS 15534. In contrast, ISIS 15534 treatment had no apparent effect on calcium induced nuclear translocation of NFAT-GFP. CONCLUSION: These studies suggest that PP5 participates in the regulation of glucocorticoid receptor nucleocytoplasmic shuttling, and that the GR-induced transcriptional activity observed when the expression of PP5 is suppressed by treatment with ISIS 15534 results from the nuclear accumulation of GR in a form that is capable of binding DNA yet still requires agonist to elicit maximal transcriptional activation
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A Multifunctional Cosolvent Pair Reveals Molecular Principles of Biomass Deconstruction
Genetic parameters of color phenotypes of black tiger shrimp (Penaeus monodon)
Black tiger shrimp (Penaeus monodon) is the second most important aquaculture species of shrimp in the world. In addition to growth traits, uncooked and cooked body color of shrimp are traits of significance for profitability and consumer acceptance. This study investigated for the first time, the phenotypic and genetic variances and relationships for body weight and body color traits, obtained from image analyses of 838 shrimp, representing the progeny from 55 sires and 52 dams. The color of uncooked shrimp was subjectively scored on a scale from 1 to 4, with â1â being the lightest/pale color and â4â being the darkest color. For cooked shrimp color, shrimp were graded firstly by subjective scoring using a commercial grading score card, where the score ranged from 1 to 12 representing light to deep coloration which was subsequently found to not be sufficiently reliable with poor repeatability of measurement (r = 0.68â0.78) Therefore, all images of cooked color were regraded on a three-point scale from brightest and lightest colored cooked shrimp, to darkest and most color-intense, with a high repeatability (r = 0.80â0.92). Objective color of both cooked and uncooked color was obtained by measurement of RGB intensities (values range from 0 to 255) for each pixel from each shrimp. Using the âconvertColorâ function in âRâ, the RGB values were converted to L*a*b* (CIE Lab) systems of color properties. This system of color space was established in 1976, by the International Commission of Illumination (CIE) where âL*â represents the measure of degree of lightness, values range from 0 to 100, where 0 = pure black and 100 = pure white. The value âa*â represents red to green coloration, where a positive value represents the color progression towards red and a negative value towards green. The value âb*â represents blue to yellow coloration, where a positive value refers to more yellowish and negative towards the blue coloration. In total, eight color-related traits were investigated. An ordinal mixed (threshold) model was adopted for manually (subjectively) scored color phenotypes, whereas all other traits were analyzed by linear mixed models using ASReml software to derive variance components and estimated breeding values (EBVs). Moderate to low heritability estimates (0.05â0.35) were obtained for body color traits. For subjectively scored cooked and uncooked color, EBV-based selection would result in substantial genetic improvement in these traits. The genetic correlations among cooked, uncooked and body weight traits were high and ranged from â0.88 to 0.81. These suggest for the first time that 1) cooked color can be improved indirectly by genetic selection based on color of uncooked/live shrimp, and 2) intensity of coloration is positively correlated with body weight traits and hence selection for body weight will also improve color traits in this population
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Intra- and interchain interactions in (Cu1/2ÂŹAu1/2)CN, (Ag1/2ÂŹAu1/2)CN, and (Cu1/3Ag1/3Au1/3)CN and their effect on one-, two- and three-dimensional order
Mixed-metal cyanides, (Cu1/2Au1/2)CN, (Ag1/2Au1/2)CN and (Cu1/3Ag1/3Au1/3)CN, adopt an AuCN-type structure in which metal-cyanide chains pack on a hexagonal lattice with metal atoms arranged in sheets. The interactions between and within the metal-cyanide chains are investigated using density-functional-theory (DFT) calculations, 13C solid-state NMR (SSNMR) and X-ray pair distribution function (PDF) measurements. Long-range metal and cyanide order is found within the chains: (âCuâNCâAuâCNâ)â, (âAgâNCâAuâCNâ)â and (âCuâNCâAgâNCâAuâCNâ)â. Although Bragg diffraction studies establish that there is no long-range order between chains, X-ray PDF results show that there is local order between chains. In (Cu1/2Au1/2)CN and (Ag1/2Au1/2)CN, there is a preference for unlike metal atoms occurring as nearest neighbours within the metal sheets. A general mathematical proof shows that the maximum average number of heterometallic nearest-neighbour interactions on a hexagonal lattice with two types of metal atom is four. Calculated energies of periodic structural models show that those with four unlike nearest neighbours are most favourable. Of these, models in space group Immm give the best fits to the X-ray PDF data out to 8 Ă
, providing good descriptions of the short- and medium-range structures. This result shows that interactions beyond those of nearest neighbours must be considered when determining the structures of these materials. Such interactions are also important in (Cu1/3Ag1/3Au1/3)CN, leading to the adoption of a structure in Pmm2 containing mixed Cu-Au and silver-only sheets arranged to maximise the numbers of CuËËËAu nearest- and next-nearest-neighbour interactions
Effect of ethnicity on access and device complications during endovascular aneurysm repair
AbstractIntroductionThere are no published reports on the association between ethnicity and outcome after aortoiliac stent grafting to treat aneurismal disease. Because Hawaii is a state with an ethnically diverse population, we conducted a retrospective study to examine this potential association. We hypothesized that individuals of Asian ancestry may have higher complication rates after endovascular repair compared with non-Asians.MethodsAll endovascular devices placed to treat aneurysm disease from 1996 to 2003 were evaluated in two institutions. The association between ethnicity and access-related and device-related complications, both periprocedural and delayed, was examined with logistic regression analysis.ResultsNinety-two aortoiliac endografts were placed during the study period, including 87 in patients with abdominal aortic aneurysms with or without iliac aneurysm disease, and five patients with isolated iliac artery aneurysms. Forty-four percent of patients were categorized as Asian, 39% as white, 16% as Pacific Islander, and 1% as African American. Access-related and device-related complications (ADRCs) occurred in 11 of 92 (12%) of these patients. The following parameters were significantly associated with ADRCs: Asian ethnicity (P =.015), age greater than 80 years (P = .02), and external iliac diameter smaller than 7.5 mm (P =.01). Asian patients were more likely to have experienced ADRCs than were non-Asian patients (odds ratio, 7.3; 95% confidence interval, 1.5-35.8; P = .015). Asians also had smaller external iliac artery diameters (P = .0003) and more tortuous iliac arteries (P = .03) compared with non-Asians. After adjusting for iliac artery diameter and tortuosity, the association between Asian ethnicity and ARDCs became nonsignificant (P = .074), which suggests that the association between race and complications may be at least in part due to small and tortuous iliac arteries. There was no association between age, gender, or ethnicity and postoperative detection of endoleak.ConclusionOur data indicate that individuals of Asian ancestry are far more likely to experience adverse access-related and device-related complications after aortoiliac stent grafting than are non-Asians. We found that this association is at least partly attributable to the smaller and more tortuous iliac arteries in persons of Asian ancestry
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