Peroxisome assembly in yeast

Peroxisomes are essential organelles that may be involved in various functions, dependent on organism, cell type, developmental stage of the cell, and the environment. Until recently, peroxisomes were viewed as a class of static organelles that developed by growth and fission from pre-existing organelles. Recent observations have challenged this view by providing evidence that peroxisomes may be part of the endomembrane system and constitute a highly dynamic population of organelles that arises and is removed upon environmental demands. Additionally, evidence is now accumulating that peroxisomes may arise by alternative methods. This review summarizes relevant recent data on this subject. In addition, the progress in the understanding of the principles of the peroxisomal matrix protein import machinery is discussed.     

Generation of Liapunov functions for time-varying nonlinear systems

A procedure for the generation of Liapunov functions for time-varying nonlinear systems is described. A composite differential one-form is derived from the basic system equations. A line integral of the one-form, withtheld constant, produces the candidate for a Liapunov function. An example is included.     

Pipeline Reconfigurable FPGAs

While reconfigurable computing promises to deliver incomparable performance, it is still a marginal technology due to the high cost of developing and upgrading applications. Hardware virtualization can be used to significantly reduce both these costs. In this paper we describe the benefits of hardware virtualization, and show how it can be achieved using the technique of pipeline reconfiguration. The result is PipeRench, an architecture that supports robust compilation and provides forward compatibility. Our preliminary performance analysis on PipeRench predicts that it will outperform commercial FPGAs and DSPs in both overall performance and in performance normalized for silicon area over a broad range of problem sizes.     

Microarray with Micro‐ and Nano‐topographies Enables Identification of the Optimal Topography for Directing the Differentiation of Primary Murine Neural Progenitor Cells

During development and tissue repair, progenitor cells are guided by both biochemical and biophysical cues of their microenvironment, including topographical signals. The topographical cues have been shown to play an important role in controlling the fate of cells. Systematic investigation of topographical structures with different geometries and sizes under the identical experimental conditions on the same chip will enhance the understanding of the role of shape and size in cell–topography interactions. A simple customizable multi‐architecture chip (MARC) array is therefore developed to incorporate, on a single chip, distinct topographies of various architectural complexities, including both isotropic and anisotropic features, in nano‐ to micrometer dimensions, with different aspect ratios and hierarchical structures. Polydimethylsiloxane (PDMS) replicas of MARC are used to investigate the influence of different geometries and sizes in neural differentiation of primary murine neural progenitor cells (mNPCs). Anisotropic gratings (2 μm gratings, 250 nm gratings) and isotropic 1 μm pillars significantly promote differentiation of mNPCs into neurons, as indicated by expression of β‐III‐tubulin (59%, 58%, and 58%, respectively, compared to 30% on the control). In contrast, glial differentiation is enhanced on isotropic 2 μm holes and 1 μm pillars. These results illustrate that anisotropic topographies enhance neuronal differentiation while isotropic topographies enhance glial differentiation on the same chip under the same conditions. MARC enables simultaneous cost‐effective investigation of multiple topographies, allowing efficient optimization of topographical and biochemical cues to modulate cell differentiation.     

Toddlers' context-varying emotions, maternal responses to emotions, and internalizing behaviors.

Relations of toddlers' observed negative affect in high- and low-threat contexts to maternal perceptions of their toddlers' internalizing problems and to mothers' responses to emotions (RTE) for fear and sadness were examined. Child-driven, parent-driven, and reciprocal transactional models across 1 year were directly compared. Two-year-old toddlers (N = 106) participated in lab-based activities to elicit distress, and their negative affect was coded. Mothers completed measures of their child's internalizing behaviors and their responses to their toddler's fear and sadness at ages 2 and 3. At age 2, only negative affect in low-threat contexts was associated with greater internalizing problems. Mothers' punishing and minimizing RTE at age 2 predicted an increase in internalizing problems across 1 year. Age 2 internalizing problems predicted an increase in mother's use of supportive RTE over time. Results highlight the importance of considering the context of toddlers' negative affective displays and supported a reciprocal conceptualization of toddlers' internalizing behaviors and mothers' RTE. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Cultivation and characterization of pterygium as an ex vivo study model for disease and therapy

Purpose

Development of ex vivo model to study pathogenesis, inflammation and treatment modalities for pterygium.

Ruminal degradation of dried brewers grains, wet brewers grains, and soybean meal

A series of trials was conducted to determine the ruminal degradation of nitrogenous compounds and dry matter of soybean meal, wet brewers grains, and dried brewers grains. In situ and in vitro estimates of degradation were positively correlated but yielded different absolute values for measures of ruminal degradation. Ruminal digestion of protein, predicted from in situ data, was 42, 73, and 83% for brewers dried grains, brewers wet grains, and soybean meal. Drying of wet grains at either 50 or 150 degrees C increased resistance to ruminal digestion equally. Measurements of flow of dry matter and nitrogen of feed origin to the duodenum were made in vivo for diets containing either brewers dried grains or soybean meal. Negative apparent digestibility of nitrogen in the rumen for a 13% crude protein, brewers dried grains ration indicates the potential for using a non-protein nitrogen supplement with this ration. Resistance to digestion of nitrogen from brewers dried grains occurred only in the rumen. Amino acid patterns delivered to the small intestine and digestion of duodenal contents were similar for diets containing brewers dried grains or soybean meal.     

The effect of hybrid nanoparticle additives on epoxy‐nanocomposite behavior and morphology

Amine modified polyhedral oligomeric silsesquioxane (POSS‐NH₂) was used to modify sodium montmorillonite (MMT) nanoclays for improved dispersion in epoxy resin. The dispersion of the clay particles was inspected using scanning electron microscopy, energy dispersive spectroscopy (EDS) and X‐Ray diffraction and the thermal properties compared using differential scanning calorimetry (DSC) and thermogravametric analysis. The introduction of the amine‐POSS was found to have a positive effect on the dispersion of the MMT clays and prevented agglomeration. The absence of clay agglomerates lead to an increase in glass transition temperature (T_g) from 44°C in the samples with the untreated clay up to 54°C in the samples with 10% additional POSS‐NH₂. The addition of POSS‐NH₂ initial increase of the weight loss (T_{d 5%}) but slowed down the rate of degradation due to the formation of an inert silica layer and eventually leading to an increased charyield. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011