166 research outputs found
Generation and annealing of defects in virgin fused silica (type III) upon ArF laser irradiation: Transmission measurements and kinetic model
Abstract The transmission of ArF laser pulses in virgin fused silica (type III) samples changes during N = 10 6 pulses at an incoming fluence H in = 5 mJ cm À2 pulse À1 . The related absorption is determined by the pulse energy absorption coefficient a(N, H in ) using a modified Beer's law, yielding initial values a ini around 0.005 cm À1 , a maximum a max 6 0.02 cm À1 at N = 10 3 -10 4 and stationary values 0.0045 cm À1 6 a end 6 0.0094 cm À1 after N % 6 · 10 5 pulses. The development a(N, H in = const.) is simulated by a rate equation model assuming a pulse number dependent E 0 center density E 0 (N). E 0 (N) is determined by a dynamic equilibrium between E 0 center generation and annealing. Generation occurs photolytically from the precursors ODC II and unstable SiH structures upon single photon absorption and from strained SiO bonds via two-photon excitation. Annealing in the dark periods between the laser pulses is dominated by the reaction of E 0 with H 2 present in the SiO 2 network. The development a(N, H in = const.) is observed for the very first sample irradiation only (virgin state). The values a end are not accessible by simple spectrophotometer measurements
Free energy approximations in simple lattice proteins
This work addresses the question of whether it is possible to define simple pairwise interaction terms to approximate free energies of proteins or polymers. Rather than ask how reliable a potential of mean force is, one can ask how reliable it could possibly be. In a two-dimensional, infinite lattice model system one can calculate exact free energies by exhaustive enumeration. A series of approximations were fitted to exact results to assess the feasibility and utility of pairwise free energy terms. Approximating the true free energy with pairwise interactions gives a poor fit with little transferability between systems of different size. Adding extra artificial terms to the approximation yields better fits, but does not improve the ability to generalize from one system size to another. Furthermore, one cannot distinguish folding from nonfolding sequences via the approximated free energies. Most usefully, the methodology shows how one can assess the utility of various terms in lattice protein/polymer models
The Role of Negative Priming in Preschoolers' Flexible Rule Use on the Dimensional Change Card Sort Task
Four experiments examined the development of negative priming (NP) in 3 -5-year-old children using as a measure of children's executive function (EF) the dimensional change card sort (DCCS) task. In the NP version of the DCCS, the values of the sorting dimension that is relevant during the preswitch phase are removed during the postswitch phase. The experiments showed that the NP effect observed in the DCCS decreased during the preschool years, and they clarified the circumstances in which NP occurs. Taken together, the findings suggest that the development of EF in early childhood consists in part in disinhibiting attention to information that has previously been suppressed
The comparative analysis of phenotypic and genotypic properties of aeromonas sobria strains isolated from rainbow trout (oncorhynchus mykiss, walbaum, 1972)
An Inhibitor of Tryptophan-Dependent Biosynthesis of Indole-3- Acetic Acid Alters Seedling Development in Arabidopsis
Abstract Although polar transport and the TIR1-dependent signaling pathway of the plant hormone auxin/indole-3-acetic acid (IAA) are well characterized, understanding of the biosynthetic pathway(s) leading to the production of IAA is still limited. Genetic dissection of IAA biosynthetic pathways has been complicated by the metabolic redundancy caused by the apparent existence of several parallel biosynthetic routes leading to IAA production. Valuabl
Cytokine-induced metabolic effects in human adipocytes are independent of endogenous nitric oxide. Am J Physiol Endocrinol Metab
ller. Cytokine-induced metabolic effects in human adipocytes are independent of endogenous nitric oxide
Ten-year follow-up results from the Goettingen Risk, Incidence and Prevalence Study (GRIPS), I: risk factors for myocardial infarction in a cohort of 5790 men. Atherosclerosis
Abstract Besides the accepted major risk factors for myocardial infarction (MI), cholesterol, hypertension and smoking, several other variables such as lipoproteins, apolipoproteins, fibrinogen and family history of MI, have been considered, but their usefulness as predictors of MI is controversially discussed. The Gö ttingen Risk Incidence and Prevalence Study (GRIPS) aimed to evaluate the independent impact of the latter in comparison to the established risk factors. GRIPS is a prospective cohort study, which included 5790 men, aged 40-59.9 years, without cardiovascular disease at baseline. Multivariate logistic regression models for the estimation of the MI risk based on the 10-year follow-up data from 97.4% of the study participants established LDL cholesterol as the strongest predictor of MI. It was followed by family history of MI, Lp(a), age, smoking, systolic blood pressure, HDL cholesterol (inversely related) and plasma glucose (PB0.00l). Apolipoprotein B as well as the ratios total/HDL cholesterol, LDL/HDL cholesterol and Apo B/AI were less effective predictors than LDL cholesterol and did not contribute independently to the estimation of MI risk. Similarly apoprotein AI was a weaker predictor of MI risk then HDL cholesterol. GRIPS is the first prospective cohort study which clearly justifies the key role of LDL cholesterol in preventive strategies. However, the data also give strong support for the additional consideration of other risk factors for a valid estimation of the MI risk for an individual subject. © 1997 Elsevier Science Ireland Ltd
ONLINE ONLY Distances between facial landmarks can be measured accurately with a new digital 3-dimensional video system
Introduction: The aim of this study was to investigate a new digital 3-dimensional infrared video system to determine its accuracy, precision, and validity in measuring facial distances. Methods: Bench experiments were performed by measuring the vertical and diagonal distances of chessboard squares of known length to determine the system's accuracy and precision. To test the system's validity, 16 healthy volunteers participated in this study. Vertical and horizontal distances of the face were measured electronically at rest, and on posed and aggressive smiles. All measurements were repeated after 8 weeks. Direct measurements of the intercanthal distance were obtained twice with calipers. Results: A minor systematic error was found in the bench experiments, with the highest absolute error of 0.227 6 0.39 mm. The analysis with this video system showed good reproducibility of all measured distances when the mean of 2 frames was used to compare distances. Digital measurements of the intercanthal distances showed high agreement with the clinically obtained values. Conclusions: This digital video system can measure geometric distances in a 3-dimensional environment with high precision. Facial distances can be measured with good accuracy and precision, allowing applications in research and clinical practice. (Am J Orthod Dentofacial Orthop 2010;137:580.e1-580.e10
Overnight foraging trips by chick-rearing Nazca Boobies Sula granti and the risk of attack by predatory fish
Improved cardiac gene transfer by transcriptional and transductional targeting of adeno-associated viral vectors
Abstract Objective: Vectors based on recombinant adeno-associated virus 2 (AAV-2) are a promising tool for cardiac gene transfer. However, potential therapeutic applications need to consider the predominant transduction of the liver once AAV-2 vectors enter the systemic circulation. We therefore aimed to increase efficiency and specificity of cardiac vector delivery by combining transcriptional and cell surface targeting. Methods: For analysis of transcriptional targeting, recombinant AAV vectors were generated harboring a luciferase reporter gene under control of the cytomegalovirus (CMV) promoter or the 1.5-kb cardiac myosin light chain promoter fused to the CMV immediate-early enhancer (CMV enh /MLC1.5). Luciferase activities were determined in representative organs three weeks after intravenous injection of the vector into adult mice. Transductional targeting was studied using luciferase-reporter constructs crosspackaged into capsids of AAV serotypes 1 to 6 and modified AAV-2 capsids devoid of binding their primary receptor heparan sulfate proteoglycan. Results: Intravenous injections of AAV-2 vectors harboring the CMV enh /MLC1.5 promoter enabled a specific and 50-fold higher reporter gene expression in left ventricular myocardium of adult mice compared to vectors containing the CMV promoter. Comparison of AAV-2 vector genomes crosspackaged into capsids of AAV-1 to -6 showed that AAV-1, -4, -5, and -6 capsids increased cardiac transduction efficiency by about 10-fold. However, transduction of other organs such as the liver was also increased after systemic administration. In contrast, AAV-2-based vectors with ablated binding to their primary receptor heparan sulfate proteoglycan enabled a significantly increased efficiency of cardiac gene transfer and reduced transduction of the liver. Conclusions: Combining transcriptional targeting by the CMV enh /MLC1.5 promoter and AAV vectors devoid of binding the AAV-2 primary receptor results in an efficient cardiac gene transfer with a significantly reduced hepatic transduction
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