Design and Evaluation of the Release Characteristics of Caffeine-Loaded Microcapsules in a Medicated Chewing Gum Formulation

The aim of this study was to microencapsulate caffeine by the emulsion technique, trying to control its release from a medicated chewing gum. Three formulations were prepared using alginate, alginate-starch, and alginate-starch with chitosan coating as the wall materials. These microcapsules were characterized with regard to the morphology studied by using an optical microscope and scanning electron microscopy (SEM), particle size, and encapsulation efficiency. The microcapsules were then incorporated into the chewing gums. The chewing gums were characterized by thermal behavior (by differential scanning calorimetry [DSC]), texture profile analysis [TPA], and sensory evaluation. Furthermore, the release of caffeine from the chewing gum was studied in vitro using the masticatory simulator and in vivo by a chew-out study. The microcapsules revealed a spherical form and high encapsulation efficiency, representing the success of the technique. The outcomes indicated that it is possible to encapsulate caffeine with the techniques employed and the microcapsules prolonged the release of caffeine throughout mastication. The chewing gum containing alginate-starch with chitosan-coated microcapsules showed the great potential of the microcapsule in controlling the release of the caffeine from the chewing gum, thereby delaying its bitterness.     

Multivariate analysis of digital gene expression profiles identifies a xylem signature of the vascular tissue of white spruce (Picea glauca)

A collection of cDNA libraries from white spruce (Picea glauca) and interior spruce (P. glauca × engelmanii) vascular tissue were analyzed to identify a set of genes that could serve as tissue-related markers within the coniferous vascular system. Multivariate exploratory methods identified up to 128 genes co-expressed similarly among three xylem libraries. The majority (87) of these genes formed three distinctive meta-clusters, denoting putative gene cliques in xylem tissue. Of the selected genes, 33 (25%) exhibited no significant sequence homology in queries against any public databases, indicating the possibility of their unique expression in the xylem tissue of conifers. Another 38 genes (30%) had ambiguous annotation. Validation of the annotated genes with analog data, obtained from a wet-lab study utilizing microarray slides with 18,881 spots, resulted in a screened list of 29 genes as xylem-related markers. Response to stress was the predominant category to which the screened genes corresponded. Among the screened genes, elements of the phenolics biosynthesis, cinnamyl alcohol dehydrogenase and laccase, together with the fundamental enzyme of the cell wall biosynthesis, cellulose synthase, prominently delineated characteristics of the wood-forming tissue, xylem.     

Nonparametric inverse-probability-weighted estimators based on the highly adaptive lasso

Inverse-probability-weighted estimators are the oldest and potentially most commonly used class of procedures for the estimation of causal effects. By adjusting for selection biases via a weighting mechanism, these procedures estimate an effect of interest by constructing a pseudopopulation in which selection biases are eliminated. Despite their ease of use, these estimators require the correct specification of a model for the weighting mechanism, are known to be inefficient, and suffer from the curse of dimensionality. We propose a class of nonparametric inverse-probability-weighted estimators in which the weighting mechanism is estimated via undersmoothing of the highly adaptive lasso, a nonparametric regression function proven to converge at nearly $n^{-1/3}$-rate to the true weighting mechanism. We demonstrate that our estimators are asymptotically linear with variance converging to the nonparametric efficiency bound. Unlike doubly robust estimators, our procedures require neither derivation of the efficient influence function nor specification of the conditional outcome model. Our theoretical developments have broad implications for the construction of efficient inverse-probability-weighted estimators in large statistical models and a variety of problem settings. We assess the practical performance of our estimators in simulation studies and demonstrate use of our proposed methodology with data from a large-scale epidemiologic study.     

Turbidimetric analysis of growth kinetics of bacteria in the laboratory environment using smartphone

For different microbiological and pathological studies, it is often required to monitor the growth of bacteria in a cultured medium in the laboratory environment. UV‐VIS spectrophotometer is commonly used to estimate the growth of bacterial cell population by measuring the absorbance at 600 nm over a period of time. Colony‐forming unit (CFU) is another approach, which has been routinely performed to estimate the live bacterial cells on semisolid agar plates. Herein, we demonstrate an alternative yet highly reliable sensing platform on a smartphone using which growth kinetics of different bacteria can be reliably monitored. The performance of the proposed smartphone sensor has been compared with the data obtained from OD600 and CFU analysis. A good correlation of bacterial growth rates enumerated based on the proposed smartphone sensor, bench‐top spectrophotometer and CFU analysis have been observed under the experimental conditions.     

Decoding Cellular Mechanisms for Mechanosensory Discrimination

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Novel Micropatterned Cardiac Cell Cultures with Realistic Ventricular Microstructure

Systematic studies of cardiac structure-function relationships to date have been hindered by the intrinsic complexity and variability of in vivo and ex vivo model systems. Thus, we set out to develop a reproducible cell culture system that can accurately replicate the realistic microstructure of native cardiac tissues. Using cell micropatterning techniques, we aligned cultured cardiomyocytes at micro- and macroscopic spatial scales to follow local directions of cardiac fibers in murine ventricular cross sections, as measured by high-resolution diffusion tensor magnetic resonance imaging. To elucidate the roles of ventricular tissue microstructure in macroscopic impulse conduction, we optically mapped membrane potentials in micropatterned cardiac cultures with realistic tissue boundaries and natural cell orientation, cardiac cultures with realistic tissue boundaries but random cell orientation, and standard isotropic monolayers. At 2 Hz pacing, both microscopic changes in cell orientation and ventricular tissue boundaries independently and synergistically increased the spatial dispersion of conduction velocity, but not the action potential duration. The realistic variations in intramural microstructure created unique spatial signatures in micro- and macroscopic impulse propagation within ventricular cross-section cultures. This novel in vitro model system is expected to help bridge the existing gap between experimental structure-function studies in standard cardiac monolayers and intact heart tissues.     

CaMKII activity is reduced in skeletal muscle during sepsis

Exercise‐induced muscle hypertrophy is associated with increased calcium/calmodulin‐dependent protein kinase II (CaMKII) expression and activity. In contrast, the influence of muscle atrophy‐related conditions on CaMKII is poorly understood. Here, we tested the hypothesis that sepsis‐induced muscle wasting is associated with reduced CaMKII expression and activity. Sepsis, induced by cecal ligation and puncture in rats, and treatment of rats with TNFα, resulted in reduced total CaMKII activity in skeletal muscle whereas autonomous CaMKII activity was unaffected. The expression of CaMKIIδ, but not β and γ, was reduced in septic muscle. In additional experiments, treatment of cultured myotubes with TNFα resulted in reduced total CaMKII activity and decreased levels of phosphorylated glycogen synthase kinase (GSK)‐3β, a downstream target of CaMKII. The present results suggest that sepsis‐induced muscle wasting is associated with reduced CaMKII activity and that TNFα may be involved in the regulation of CaMKII activity in skeletal muscle. Decreased phosphorylation (consistent with activation) of GSK‐3β may be a consequence of reduced CaMKII activity, indicating that inhibited CaMKII activity may be involved in the catabolic response to sepsis. J. Cell. Biochem. 114: 1294–1305, 2013. © 2012 Wiley Periodicals, Inc.