The lean oxidation of iso-octane at elevated pressures

Both spark-ignition and compression-ignition engines burn large molecular-weight blended fuels, a class to which the primary reference fuels (PRF), n-heptane and iso-octane belong. In this study experiments were performed using iso-octane in a high pressure flow reactor at a temperature of 925 K, at 3, 6 and 9 atm pressure and with a fuel/air equivalence ratio of approximately 0.05. Many hydrocarbon and oxygenated hydrocarbon intermediates were identified and quantified as a function of time. These experimental results provide a strin- gent test of the low temperature chemistry portion of a kinetic model as they emphasise the importance of alkyl radical addition to molecular oxygen and internal H-atom isomerization reactions relative to alkyl radical decomposition reactions. A detailed chemical kinetic mechanism is used to simulate these experiments. We provide comparisons of model predictions with experimentally measured species profiles and describe how each species is formed as predicted by the detailed model

School-Based Prevention Of Depressive Symptoms: A Randomized Controlled Study Of The Effectiveness And Specificity Of The Penn Resiliency Program

The authors investigated the effectiveness and specificity of the Penn Resiliency Program (PRP; J. E. Gillham, L. H. Jaycox, K. J. Reivich, M. E. P. Seligman, & T. Silver, 1990), a cognitive-behavioral depression prevention program. Children (N = 697) from 3 middle schools were randomly assigned to PRP, Control (CON), or the Penn Enhancement Program (PEP; K. J. Reivich, 1996; A. J. Shatté, 1997), an alternate intervention that controls for nonspecific intervention ingredients. Children\u27s depressive symptoms were assessed through 3 years of follow-up. There was no intervention effect on average levels of depressive symptoms in the full sample. Findings varied by school. In 2 schools, PRP significantly reduced depressive symptoms across the follow-up relative to both CON and PEP. In the 3rd school, PRP did not prevent depressive symptoms. The authors discuss the findings in relation to previous research on PRP and the dissemination of prevention programs. (PsycINFO Database Record (c) 2013 APA, all rights reserved)(journal abstract

Enhancing students’ motivation to learn software engineering programming techniques: a collaborative and social interaction approach

To motivate students to study advanced programming techniques, including the use of architectural styles such as the model–view–controller pattern, we have con-ducted action research upon a project based-learning approach. In addition to collabo-ration, the approach includes students’ searching and analysis of scientific documents and their involvement in communities of practice outside academia. In this paper, we report the findings of second action research cycle, which took place throughout the fourth semester of a six-semester program. As with the previous cycle during the pre-vious academic year, students did not satisfactorily achieve expected learning out-comes. More groups completed the assigned activities, but results continue to reflect poor engagement in the communities of practice and very low performance in other learning tasks. From the collected data we have identified new approaches and recom-mendations for subsequent research.Fundação para a Ciência e Tecnologia (FCT), Portugal, for Ph.D. Grants SFRH/BD/91309/2012 and SFRH/BD/87815/201

Shape coexistence in Hg-178

Lifetime measurements of excited states in Hg-178 have been performed using the Rh-103(Kr-78, p2n) reaction at a beam energy of 354 MeV. The recoil-decay tagging (RDT) technique was applied to select the Hg-178 nuclei and associate the prompt gamma rays with the correlated characteristic ground-state alpha decay. Lifetimes of the four lowest yrast states of Hg-178 have been determined using the recoil distance Doppler-shift (RDDS) method. The experimental data are compared to theoretical predictions with focus on shape coexistence. The results confirm the shift of the deformed prolate structures to higher lying states but also indicate their increasing deformation with decreasing neutron number.Peer reviewe

Lifetime measurements in the transitional nucleus Gd-138

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A Peptidoglycan Fragment Triggers β-lactam Resistance in Bacillus licheniformis

To resist to β-lactam antibiotics Eubacteria either constitutively synthesize a β-lactamase or a low affinity penicillin-binding protein target, or induce its synthesis in response to the presence of antibiotic outside the cell. In Bacillus licheniformis and Staphylococcus aureus, a membrane-bound penicillin receptor (BlaR/MecR) detects the presence of β-lactam and launches a cytoplasmic signal leading to the inactivation of BlaI/MecI repressor, and the synthesis of a β-lactamase or a low affinity target. We identified a dipeptide, resulting from the peptidoglycan turnover and present in bacterial cytoplasm, which is able to directly bind to the BlaI/MecI repressor and to destabilize the BlaI/MecI-DNA complex. We propose a general model, in which the acylation of BlaR/MecR receptor and the cellular stress induced by the antibiotic, are both necessary to generate a cell wall-derived coactivator responsible for the expression of an inducible β-lactam-resistance factor. The new model proposed confirms and emphasizes the role of peptidoglycan degradation fragments in bacterial cell regulation

Effect of Liposome Characteristics and Dose on the Pharmacokinetics of Liposomes Coated with Poly(amino acid)s

Long-circulating liposomes, such as PEG-liposomes, are frequently studied for drug delivery and diagnostic purposes. In our group, poly(amino acid) (PAA)-based coatings for long-circulating liposomes have been developed. These coatings provide liposomes with similar circulation times as compared to PEG-liposomes, but have the advantage of being enzymatically degradable. For PEG-liposomes it has been reported that circulation times are relatively independent of their physicochemical characteristics. In this study, the influence of factors such as PAA grafting density, cholesterol inclusion, surface charge, particle size, and lipid dose on the circulation kinetics of PAA-liposomes was evaluated after intravenous administration in rats. Prolonged circulation kinetics of PAA-liposomes can be maintained upon variation of liposome characteristics and the lipid dose given. However, the use of relatively high amounts of strongly charge-inducing lipids and a too large mean size is to be avoided. In conclusion, PAA-liposomes represent a versatile drug carrier system for a wide variety of applications

Nanoparticles that communicate in vivo to amplify tumour targeting

Author Manuscript: 2012 May 29Nanomedicines have enormous potential to improve the precision of cancer therapy, yet our ability to efficiently home these materials to regions of disease in vivo remains very limited. Inspired by the ability of communication to improve targeting in biological systems, such as inflammatory-cell recruitment to sites of disease, we construct systems where synthetic biological and nanotechnological components communicate to amplify disease targeting in vivo. These systems are composed of ‘signalling’ modules (nanoparticles or engineered proteins) that target tumours and then locally activate the coagulation cascade to broadcast tumour location to clot-targeted ‘receiving’ nanoparticles in circulation that carry a diagnostic or therapeutic cargo, thereby amplifying their delivery. We show that communicating nanoparticle systems can be composed of multiple types of signalling and receiving modules, can transmit information through multiple molecular pathways in coagulation, can operate autonomously and can target over 40 times higher doses of chemotherapeutics to tumours than non-communicating controls.National Cancer Institute (U.S.) (SBMRI Cancer Center Support Grant 5 P30 CA30199-28)National Cancer Institute (U.S.) (MIT CCNE Grant U54 CA119349)National Cancer Institute (U.S.) (Bioengineering Research Partnership Grant 5-R01-CA124427)National Cancer Institute (U.S.) (UCSD CCNE Grant U54 CA 119335)National Science Foundation (U.S.) (Whitaker Graduate Fellowship