Microsatellite instability is correlated with lymph node-positive breast cancer

1. P-glycoprotein, a 170-180 kDa membrane glycoprotein that mediates multidrug resistance, hydrolyses ATP to efflux a broad spectrum of hydrophobic agents. In this study, we analysed the effects of three MDR reversing agents, verapamil, cyclosporin A and [3'-keto-Bmt1]-[Val2]-cyclosporin (PSC 833), on the adenosine triphosphatase (ATPase) activity of human P-glycoprotein. 2. P-glycoprotein was immunoprecipitated with a monoclonal antibody (MRK-16) and the P-glycoprotein-MRK-16-Protein A-Sepharose complexes obtained were subjected to a coupled enzyme ATPase assay. 3. While verapamil activated the ATPase, the cyclosporin derivatives inhibited both the substrate-stimulated and the basal P-glycoprotein ATPase. No significant difference was observed between PSC 833 and cyclosporin A on the inhibition of basal P-glycoprotein ATPase activity. PSC 833 was more potent than cyclosporin A for the substrate-stimulated activity. 4. Kinetic analysis indicated a competitive inhibition of verapamil-stimulated ATPase by PSC 833. 5. The binding of 8-azido-[alpha-32P]-ATP to P-glycoprotein was not altered by the cyclosporin derivatives, verapamil, vinblastine and doxorubicin, suggesting that the modulation by these agents of P-glycoprotein ATPase cannot be attributed to an effect on ATP binding to P-glycoprotein. 6. The interaction of the cyclosporin derivatives with ATPase of P-glycoprotein might present an alternative and/or additional mechanism of action for the modulation of P-glycoprotein function.     

On-line maintenance of triconnected components with SPQR-trees

We consider the problem of maintaining on-line the triconnected components of a graphG. Letn be the current number of vertices ofG. We present anO(n)-space data structure that supports insertions of vertices and edges, and queries of the type “Are there three vertex-disjoint paths between verticesv ₁ andv ₂?” A sequence ofk operations takes timeO(k·α(k, n)) ifG is biconnected(α(k, n) denotes the well-known Ackermann's function inverse), and timeO(n logn+k) ifG is not biconnected. Note that the bounds do not depend on the number of edges ofG. We use theSPQR-tree, a versatile data structure that represents the decomposition of a biconnected graph with respect to its triconnected components, and theBC-tree, which represents the decomposition of a connected graph with respect to its biconnected components.     

Origin and gender determination of dried blood on a statue of the Virgin Mary

The durations and variability of changing events were analyzed for 20 min. each of 13 children's television programs. These programs included selections from both publically and privately produced shows. Significantly different patterns of attentional demands were found between the programs. Public television programming is characterized by longer and more variable durations of sustained attentional events, while private television programming is best described as having fast-paced shorter events. The implications of this finding for difficulties in learning by school-age children to attend for longer periods are discussed.     

LCA evaluation for the hydrogen production from biogas through the innovative BioRobur project concept

BioRobur is a project aimed to produce hydrogen from biogas through an auto-thermal reforming (ATR) process, in which innovative catalytic systems are used to promote the ATR reactions involved in the process for the conversion of biogas into syngas. A detailed LCA study of hydrogen production from biogas ATR using the BioRobur technology has been performed. LCA analysis has been also conducted for other two conventional processes for the production of hydrogen from biogas: the steam reforming and water hydrolysis (a biogas-fueled Internal Combustion engine (ICE) followed by an Electrolyser). A comparison between these technologies has been made from both the environmental and the energetic viewpoints. The LCA has demonstrated that BioRobur is the most environmentally friendly of considered processes. Moreover, the ICE plus Electrolyser has resulted to be the because of the very large amount of biogas needed for the least efficient process, due to the low conversion yield of biogas into energy of the ICE.     

miR-125b Regulates the Early Steps of ESC Differentiation through Dies1 in a TGF-Independent Manner

Over the past few years, it has become evident that the distinctive pattern of miRNA expression seen in embryonic stem cells (ESCs) contributes to important signals in the choice of the cell fate. Thus, the identification of miRNAs and their targets, whose expression is linked to a specific step of differentiation, as well as the modulation of these miRNAs, may prove useful in the learning of how ESC potential is regulated. In this context, we have studied the expression profile of miRNAs during neural differentiation of ESCs. We have found that miR-125b is upregulated in the first steps of neural differentiation of ESCs. This miRNA targets the BMP4 co-receptor, Dies1, and, in turn, regulates the balance between BMP4 and Nodal/Activin signaling. The ectopic expression of miR-125b blocks ESC differentiation at the epiblast stage, and this arrest is rescued by restoring the expression of Dies1. Finally, opposite to miR-125a, whose expression is under the control of the BMP4, miR-125b is not directly regulated by Transforming Growth Factor beta (TGFβ) signals. These results highlight a new important role of miR-125b in the regulation of the transition from ESCs to the epiblast stage and add a new level of control on TGFβ signaling in ESCs.     

Turbulent consumption speed via local dilatation rate measurements in a premixed bunsen jet

The mean local reaction rate related to the average expansion across the front and computed from the mean velocity divergence is evaluated in this work. Measurements are carried out in a air/methane premixed jet flame by combined PIV/LIF acquisitions. The procedure serves the purpose of obtaining values of a turbulent flame speed, namely the local turbulent consumption speed S_LC, as a function of the position along the bunsen flame. With the further position that the flamelet assumption provides a proportionality between turbulent burning speed normalized with the laminar unstretched one and the turbulent to average flame surface ratio, the proportionality constant, i.e., the stretching factor becomes available. The results achieved so far show the existence of a wide region along which the bunsen flame front has a constant stretching factor which apparently depends only on the ratio between turbulent fluctuations and laminar flame speed and on the jet Reynolds number.     

Social-cognitive interactions, motivation, and cognitive growth in Logo programming and CAI problem-solving environments.

Extending earlier work by D. H. Clements and B. K. Nastasi (1985, 1988), this study investigated whether children working in two educational computing environments—Logo and computer-assisted instruction (CAI) problem-solving—exhibited differing amounts of behaviors indicative of cooperative interaction, conflict and resolution, effectance motivation, and self-evaluation. Ss were 12 fourth and 28 sixth graders randomly assigned to Logo or CAI. Toward the end of 42 treatment sessions, Ss working in pairs were videotaped. Children in Logo evinced more cognitively oriented conflict, attempts at and successful resolution of conflicts, rule making, and pleasure at discovery. Resolution of cognitive conflict more than the occurrence of conflict predicted problem-solving performance and accounted for treatment effects on problem solving. Findings suggest that Logo may foster cognitive growth through opportunities for resolving cognitive conflict and may enhance effectance motivation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)