Pneumococcal polysaccharide vaccine in children with chronic renal disease: a prospective study of antibody response and duration

We studied the antibody response to pneumococcal serotypes 3 and 14 after pneumococcal polysaccharide vaccine was administered to 41 children with renal disease. One month after vaccination, 76% and 61% of patients achieved at least a twofold titer rise to serotypes 3 and 14, respectively; this finding was comparable to historic control values. One year after vaccination, the majority of patients retained protective antibody levels. Achieving a titer > or = 1.0 microgram/ml IgG at 1 month was highly predictive of retaining a protective antibody level > or = 0.15 microgram/ml at 1 year.     

Training parsers by inverse reinforcement learning

One major idea in structured prediction is to assume that the predictor computes its output by finding the maximum of a score function. The training of such a predictor can then be cast as the problem of finding weights of the score function so that the output of the predictor on the inputs matches the corresponding structured labels on the training set. A similar problem is studied in inverse reinforcement learning (IRL) where one is given an environment and a set of trajectories and the problem is to find a reward function such that an agent acting optimally with respect to the reward function would follow trajectories that match those in the training set. In this paper we show how IRL algorithms can be applied to structured prediction, in particular to parser training. We present a number of recent incremental IRL algorithms in a unified framework and map them to parser training algorithms. This allows us to recover some existing parser training algorithms, as well as to obtain a new one. The resulting algorithms are compared in terms of their sensitivity to the choice of various parameters and generalization ability on the Penn Treebank WSJ corpus.     

Characterization of a miniaturized liquid bridge for nL sample infusion: a comparative study of sample flush-out behavior using flow simulations and direct ESI-MS analysis

In this work we shed light on the microfluidics of a miniaturized liquid bridge that forms the central part of a so-called “capillary gap sampler,” a novel device for rapid and seamless injection of nanoliter sample volumes into an electrospray ionization mass spectrometer (ESI-MS). Parameters relevant for sample flush-out at the liquid bridge and in the spray capillary were identified by systematic variation of the capillary dimensions, the linear buffer flow rate (2.1–34 mm/s) and molecular weight of the analytes (0.5–30 kDa). We found that a reduction in capillary wall thickness by a factor of 1.6 significantly influences analyte peak shapes, leads to an inversion of the relationship between peak width and analyte molecular weight, and allows a fivefold decrease in peak width for large molecules down to 5 s. The results could be verified and explained by simulations, in which the presence of diffusion-controlled “dead zones” at the liquid bridge and dispersion in the spray tip that depend on analyte molecular weight were identified as key factors relevant for the sample flush-out process. The merging of simulations and experimental data gives useful hints toward the re-design of a spray tip as built-in ESI-MS interface for an optimized gap sampler performance.     

LIFE PREDICTION OF CROSS-PLY METAL MATRIX COMPOSITES UNDERGOING THERMOMECHANICAL FATIGUE

A life prediction model that was originally developed for the axial loading of unidirectional metal matrix composites (MMCs) undergoing combined thermal and mechanical loading is extended to the axial loading of cross-ply MMCs by adding an internally initiated matrix fatigue damage term. This new term accounts for the growth of cracks that initiate at the location where fibre–matrix separation occurs in the transversely-oriented plies. A comparison of the model predictions to experimental data on SCS-6/Timetal 21S shows that the model reasonably accounts for the dependence of applied stress, temperature and environment, as well as cyclic frequency. The dominant damage accumulation process for cross-ply MMCs with weak fibre–matrix bonds is described by this internally initiated matrix fatigue damage process for most stress–temperature cycle combinations. However, the fibre-dominated damage accumulation process operates under in-phase TMF when both stress and temperature are high. Environment-enhanced matrix fatigue is the dominant damage accumulation process under isothermal fatigue when stress is low and temperature is high.     

Stabilizing Mean Values and Minimizing Variances of Electronic Systems Performance Criteria

Mathematical statistics are used to design electronic systems in which the effects of the initial variations of the system parameters and the drift of these parameters on the system performance criteria are a minimum. This is accomplished by minimizing the initial variances of the system performance criteria with respect to the initial mean values of the system parameters while constraining the means of these parameters to their required values. In addition, the drift rates of the system parameters are selected in such a manner as to prevent the drift of the mean values of the system performance criteria while reducing the tendencies of the variances of these criteria to increase with time. These techniques were successfully applied to a number of electronic systems, including systems with both active and passive elements, thus illustrating the usefulness of mathematical statistics in the design of mass produced electronic systems.     

High resolution scanning transmission electron microscopy (HR STEM) analysis of re-deposited layer on ASDEX Upgrade tile

Erosion and re-deposition of plasma-facing components (PFCs) is one of the most important issues in fusion devices and as such it is an area of interest for many research groups. However, the structure and composition of re-deposited layers as well as the mechanism and condition of their formation are not yet fully described and understood.In the present study, the structure and the composition of co-deposited layers, which developed at the outer divertor strike point tiles in ASDEX Upgrade during the 2009 campaign were examined. High resolution scanning transmission electron microscopy (HRSTEM) combined with energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) have been used to identify deposits composition and morphology. Tungsten foam like structure and co-deposits rich in tungsten, oxygen, carbon, boron and nitrogen were observed.     

Combined application of 13C NMR spectroscopy and confocal laser scanning microscopy—Investigation on biofilm structure and physico-chemical properties

Long-term biofilm processes are influenced by the interplay of biofilm accumulation and detachment, which in turn depend partially on the biofilm structure and composition. In this study a combination of confocal laser scanning microscopy (CLSM) and nuclear magnetic resonance (NMR) spectroscopy was applied to analyze biofilm structure, composition and molecular mobility. Whereas CLSM delivers information about the structure of biofilms the NMR measurement provides detailed but not locally resolved information about the chemical composition of biofilm constituents. Heterotrophic mixed-species biofilms were cultivated in rotating annular reactors exposed to different flow conditions and glucose concentrations in order to obtain biofilms with diverse architectural structures. The growth state of the biofilms appeared to influence the composition of biofilm and detached biomass. The difference in the ¹³C NMR spectra between the differently structured biofilms or between biofilm and detached biomass was small, except for the still exponential growing biofilm supplied with the highest glucose concentration. More information was gained from the mobility of specific molecular groups within the biofilm biomass. Molecules within the biofilm biomass of the non-filamentous biofilms were more strongly bound than the molecules within the respective detached biomass. Glucose starvation resulted in a reduction in the biofilm molecular mobility. The opposite was observed in the filamentous biofilm. In this case, the molecular mobility in the biofilm increased after starvation and the molecules in the detached biomass were bound more strongly than in the respective biofilm biomass. It could be shown that the combination of CLSM and ¹³C NMR spectroscopy is a promising approach to analyze the interactions between biofilm architecture, composition or growth state and biofilm detachment.     

Polymer Mechanics as a Model for Short-Term and Flow-Independent Cartilage Viscoelasticity

Articular cartilage is the load bearing soft tissue that covers the contacting surfaces of long bones in articulating joints. Healthy cartilage allows for smooth joint motion, while damaged cartilage prohibits normal function in debilitating joint diseases such as osteoarthritis. Knowledge of cartilage mechanical function through the progression of osteoarthritis, and in response to innovative regeneration treatments, requires a comprehensive understanding of the molecular nature of interacting extracellular matrix constituents and interstitial fluid. The objectives of this study were therefore to (1) examine the timescale of cartilage stress-relaxation using different mechanistic models and (2) develop and apply a novel (termed "sticky") polymer mechanics model to cartilage stress-relaxation based on temporary binding of constituent macromolecules. Using data from calf cartilage samples, we found that different models captured distinct timescales of cartilage stress-relaxation: monodisperse polymer reptation best described the first second of relaxation, sticky polymer mechanics best described data from ～1-100 seconds of relaxation, and a model of inviscid fluid flow through a porous elastic matrix best described data from 100 seconds to equilibrium. Further support for the sticky polymer model was observed using experimental data where cartilage stress-relaxation was measured in either low or high salt concentration. These data suggest that a complete understanding of cartilage mechanics, especially in the short time scales immediately following loading, requires appreciation of both fluid flow and the polymeric behavior of the extracellular matrix.