457 research outputs found
On the Existence of the Logarithmic Correction Term in Black Hole Entropy-Area Relation
In this paper we consider a model universe with large extra dimensions to
obtain a modified black hole entropy-area relation. We use the generalized
uncertainty principle to find a relation between the number of spacetime
dimensions and the presence or vanishing of logarithmic prefactor in the black
hole entropy-area relation. Our calculations are restricted to the
microcanonical ensembles and we show that in the modified entropy-area
relation, the microcanonical logarithmic prefactor appears only when spacetime
has an even number of dimensions.Comment: 9 Pages, No Figure
MEDICATION, ENVIRONMENTAL, AND PATIENT FACTORS THAT INFLUENCE MEDICATION ADMINISTRATION DELIVERY TIMES
The purpose of this study was to identify the medication factors, environmental factors, and patient factors that predict medication time errors by registered nurses in an acute care setting. A sample of 1032 observations was analyzed using multivariate logistic regression using generalized estimating equations modeling. The findings suggested that time errors during medication administration were independently associated with time-critical medications, the number of medications that the patient received at the scheduled administration time, and the patient’s swallowing ability. This study also found that the time of administration for the majority of medications was not accurately documented
Human monocytes augment invasiveness and proteolytic activity of inflammatory breast cancer
Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer, and here, we examined in vitro the interactions between the human IBC cell line SUM149 and U937 human naive monocytes. We found an altered morphology, enhanced invasiveness and proteolytic activity of SUM149 cells when cultured with U937 cells or in U937-conditioned media (U937-CM). Increases in expression and activity of the cysteine protease cathepsin B and expression of caveolin-1 were also detected in SUM149 cells grown in U937-CM, thus suggesting a contribution of these proteins to the augmented invasion through and proteolysis of the extracellular matrix by the IBC cells
Precipitation of metallic chromium during rapid cooling of Cr2O3 slags
The slag systems of CaO-SiO2- Cr2O3 and Al2O3-CaO-MgO-SiO2- Cr2O3 were analyzed. These slag systems occur in the production of stainless steel and are important from the process metallurgy point of view. Synthetic slag samples with different chromium oxide content were prepared and melted. The melted slag samples where then rapidly cooled on large steel plates, so that the high temperature microstructure was preserved. The samples were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The precipitation of different chromium oxide phases was studied, but most importantly the precipitation of metallic chromium was observed. These findings help us interpret industrial slag samples
Pathomimetic cancer avatars for live-cell imaging of protease activity
Proteases are essential for normal physiology as well as multiple diseases, e.g., playing a causative role in cancer progression, including in tumor angiogenesis, invasion, and metastasis. Identification of dynamic alterations in protease activity may allow us to detect early stage cancers and to assess the efficacy of anti-cancer therapies. Despite the clinical importance of proteases in cancer progression, their functional roles individually and within the context of complex protease networks have not yet been well defined. These gaps in our understanding might be addressed with: 1) accurate and sensitive tools and methods to directly identify changes in protease activities in live cells, and 2) pathomimetic avatars for cancer that recapitulate in vitro the tumor in the context of its cellular and non-cellular microenvironment. Such avatars should be designed to facilitate mechanistic studies that can be translated to animal models and ultimately the clinic. Here, we will describe basic principles and recent applications of live-cell imaging for identification of active proteases. The avatars optimized by our laboratory are three-dimensional (3D) human breast cancer models in a matrix of reconstituted basement membrane (rBM). They are designated mammary architecture and microenvironment engineering (MAME) models as they have been designed to mimic the structural and functional interactions among cell types in the normal and cancerous human breast. We have demonstrated the usefulness of these pathomimetic avatars for following dynamic and temporal changes in cell:cell interactions and quantifying changes in protease activity associated with these interactions in real-time (4D). We also briefly describe adaptation of the avatars to custom-designed and fabricated tissue architecture and microenvironment engineering (TAME) chambers that enhance our ability to analyze concomitant changes in the malignant phenotype and the associated tumor microenvironment
Microstructural evolution of inconel 625 during thermal aging
Inconel 625 is due to alloying elements prone to precipitation of different intermetallic phases and secondary carbides during thermal aging. The base of investigation is nickel superalloy Inconel 625 in hot rolled state. Thermal aging was conducted at temperature 650 °C with different duration of treatment for each sample. Microstructural analysis was performed by light microscope and scanning electron microscope. The results of microstructure observation showed the precipitation of intermetallic γ››- Ni3Nb phase in the γ matrix and δ-Ni3Nb phase with M23C6 secondary carbides at the grain boundaries
Bouncing cosmological solutions and their stability
In the present paper we consider the bouncing braneworld scenario, in which
the bulk is given by a five-dimensional charged AdS black hole spacetime with
matter field confined in a brane. Then, we study the stability of
solutions with respect to homogeneous and isotropic perturbations.
Specifically, the AdS black hole with zero ADM mass and charge, and open
horizon is an attractor, while the charged AdS black hole with zero ADM mass
and flat horizon, is a repeller.Comment: 9 pages, 1 figur
Caveolin-1 mediates the expression and localization of cathepsin B, pro-urokinase plasminogen activator and their cell-surface receptors in human colorectal carcinoma cells
Cathepsin B and pro-urokinase plasminogen activator (pro-uPA) localize to the caveolae of HCT 116 human colorectal carcinoma cells, an association mediated by active K-RAS. In this study, we established a stable HCT 116 cell line with a gene encoding antisense caveolin-1 (AS-cav-1) to examine the effects of caveolin-1, the main structural protein of caveolae, on the expression and localization of cathepsin B and pro-uPA, and their cell-surface receptors p11 and uPA receptor (uPAR), respectively. AS-cav-1 HCT 116 cells secreted less procathepsin B than control (empty vector) cells as measured by immunoblotting and pepsin activation of the proenzyme. Expression and secretion of pro-uPA was also downregulated in AS-cav-1 HCT 116 cells. Localization of cathepsin B and pro-uPA to caveolae was reduced in AS-cav-1 HCT 116 cells, and these cells expressed less total and caveolae-associated p11 and uPAR compared with control cells. Previous studies have shown that uPAR forms a complex with caveolin-1 and beta1-integrin, and we here show that downregulation of caveolin-1 also suppressed the localization of beta1-integrin to caveolae of these cells. Finally, downregulation of caveolin-1 in HCT 116 cells inhibited degradation of the extracellular matrix protein collagen IV and the invasion of these cells through Matrigel. Based on these results, we hypothesize that caveolin-1 affects the expression and localization of cathepsin B and pro-uPA, and their receptors, thereby mediating cell-surface proteolytic events associated with invasion of colon cancer cells
Gender differences in identities and their socio-structural correlates: how gendered lives shape parental and work identities
This study draws on identity theory to explore parental and work identities. It examined gender differences in identities, as well as the moderating role of gender in the effects of individuals’ socio-structural characteristics. A sample of 148 couples with young children completed extensive questionnaires. As hypothesized, couples’ paid work strategy moderated gender differences in the salience and centrality of parental and work identities. Whereas significant differences in identities were found between stay-at-home mothers and their breadwinning husbands, no differences were found among dual-earner couples. Moreover, men’s work identity centrality increased when they had more and younger children, whereas women’s work identity centrality decreased. Finally, men’s parental identity centrality increased with their income, whereas women’s parental identity centrality decreased the more they earned. These findings attest to the importance of examining differences within as well as between genders, by taking into account the interactive effects of gender with other socio-structural characteristics
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