Preparation of Pectin–ZnO Nanocomposite

Pectin–ZnO nanocomposite was prepared in the aqueous solution condition at room temperature. The Fourier transform infrared, X-ray diffraction, and transmission electron microscope (TEM) measurements confirmed the nanoscaled structure of pectin–ZnO composite. According to the TEM observation, the average composite granules size was about 150 nm and the embedded ZnO nanoparticles were uniform with an average diameter of 70 nm

Academic Performance and Behavioral Patterns

Identifying the factors that influence academic performance is an essential part of educational research. Previous studies have documented the importance of personality traits, class attendance, and social network structure. Because most of these analyses were based on a single behavioral aspect and/or small sample sizes, there is currently no quantification of the interplay of these factors. Here, we study the academic performance among a cohort of 538 undergraduate students forming a single, densely connected social network. Our work is based on data collected using smartphones, which the students used as their primary phones for two years. The availability of multi-channel data from a single population allows us to directly compare the explanatory power of individual and social characteristics. We find that the most informative indicators of performance are based on social ties and that network indicators result in better model performance than individual characteristics (including both personality and class attendance). We confirm earlier findings that class attendance is the most important predictor among individual characteristics. Finally, our results suggest the presence of strong homophily and/or peer effects among university students

Comparison of HIV-1 Genotypic Resistance Test Interpretation Systems in Predicting Virological Outcomes Over Time

Background: Several decision support systems have been developed to interpret HIV-1 drug resistance genotyping results. This study compares the ability of the most commonly used systems (ANRS, Rega, and Stanford's HIVdb) to predict virological outcome at 12, 24, and 48 weeks. Methodology/Principal Findings: Included were 3763 treatment-change episodes (TCEs) for which a HIV-1 genotype was available at the time of changing treatment with at least one follow-up viral load measurement. Genotypic susceptibility scores for the active regimens were calculated using scores defined by each interpretation system. Using logistic regression, we determined the association between the genotypic susceptibility score and proportion of TCEs having an undetectable viral load (<50 copies/ml) at 12 (8-16) weeks (2152 TCEs), 24 (16-32) weeks (2570 TCEs), and 48 (44-52) weeks (1083 TCEs). The Area under the ROC curve was calculated using a 10-fold cross-validation to compare the different interpretation systems regarding the sensitivity and specificity for predicting undetectable viral load. The mean genotypic susceptibility score of the systems was slightly smaller for HIVdb, with 1.92±1.17, compared to Rega and ANRS, with 2.22±1.09 and 2.23±1.05, respectively. However, similar odds ratio's were found for the association between each-unit increase in genotypic susceptibility score and undetectable viral load at week 12; 1.6 [95% confidence interval 1.5-1.7] for HIVdb, 1.7 [1.5-1.8] for ANRS, and 1.7 [1.9-1.6] for Rega. Odds ratio's increased over time, but remained comparable (odds ratio's ranging between 1.9-2.1 at 24 weeks and 1.9-2.

Improving phylogeny reconstruction at the strain level using peptidome datasets

Typical bacterial strain differentiation methods are often challenged by high genetic similarity between strains. To address this problem, we introduce a novel in silico peptide fingerprinting method based on conventional wet-lab protocols that enables the identification of potential strain-specific peptides. These can be further investigated using in vitro approaches, laying a foundation for the development of biomarker detection and application-specific methods. This novel method aims at reducing large amounts of comparative peptide data to binary matrices while maintaining a high phylogenetic resolution. The underlying case study concerns the Bacillus cereus group, namely the differentiation of Bacillus thuringiensis, Bacillus anthracis and Bacillus cereus strains. Results show that trees based on cytoplasmic and extracellular peptidomes are only marginally in conflict with those based on whole proteomes, as inferred by the established Genome-BLAST Distance Phylogeny (GBDP) method. Hence, these results indicate that the two approaches can most likely be used complementarily even in other organismal groups. The obtained results confirm previous reports about the misclassification of many strains within the B. cereus group. Moreover, our method was able to separate the B. anthracis strains with high resolution, similarly to the GBDP results as benchmarked via Bayesian inference and both Maximum Likelihood and Maximum Parsimony. In addition to the presented phylogenomic applications, whole-peptide fingerprinting might also become a valuable complementary technique to digital DNA-DNA hybridization, notably for bacterial classification at the species and subspecies level in the future.This research was funded by Grant AGL2013-44039-R from the Spanish “Plan Estatal de I+D+I”, and by Grant EM2014/046 from the “Plan Galego de investigación, innovación e crecemento 2011-2015”. BS was recipient of a Ramón y Cajal postdoctoral contractfrom the Spanish Ministry of Economyand Competitiveness. This work was also partially funded by the [14VI05] Contract-Programme from the University of Vigo and the Agrupamento INBIOMED from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273).The research leading to these results has also received funding from the European Union’s Seventh Framework Programme FP7/REGPOT-2012-2013.1 under grant agreement n˚ 316265, BIOCAPS. This document reflects only the authors’ views and the European Union is not liable for any use that may be made of the information contained herein. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

The Genealogical Population Dynamics of HIV-1 in a Large Transmission Chain:Bridging within and among Host Evolutionary Rates

Transmission lies at the interface of human immunodeficiency virus type 1 (HIV-1) evolution within and among hosts and separates distinct selective pressures that impose differences in both the mode of diversification and the tempo of evolution. In the absence of comprehensive direct comparative analyses of the evolutionary processes at different biological scales, our understanding of how fast within-host HIV-1 evolutionary rates translate to lower rates at the between host level remains incomplete. Here, we address this by analyzing pol and env data from a large HIV-1 subtype C transmission chain for which both the timing and the direction is known for most transmission events. To this purpose, we develop a new transmission model in a Bayesian genealogical inference framework and demonstrate how to constrain the viral evolutionary history to be compatible with the transmission history while simultaneously inferring the within-host evolutionary and population dynamics. We show that accommodating a transmission bottleneck affords the best fit our data, but the sparse within-host HIV-1 sampling prevents accurate quantification of the concomitant loss in genetic diversity. We draw inference under the transmission model to estimate HIV-1 evolutionary rates among epidemiologically-related patients and demonstrate that they lie in between fast intra-host rates and lower rates among epidemiologically unrelated individuals infected with HIV subtype C. Using a new molecular clock approach, we quantify and find support for a lower evolutionary rate along branches that accommodate a transmission event or branches that represent the entire backbone of transmitted lineages in our transmission history. Finally, we recover the rate differences at the different biological scales for both synonymous and non-synonymous substitution rates, which is only compatible with the 'store and retrieve' hypothesis positing that viruses stored early in latently infected cells preferentially transmit or establish new infections upon reactivation.status: publishe

Controlled release of levamisole from poly-(epsilon-caprolactone) matrices .2. Effects of water-soluble polymer and iron powder incorporated into the matrices

Mixtures of hydrophobic-polymer/hydrophilic-polymer and hydrophobic-polymer/hydrophilic-polymer/iron powder were evaluated for the construction of rumino-reticulum devices (RRDs) containing levamisole hydrochloride as anthelmintic agent. A faster release profile of levamisole was achieved by incorporating a hydrophilic polymer such as polyethylene glycol 6000 and/or iron powder into a hydrophobic polymer such as poly-(epsilon-caprolactone) constituting the biodegradable matrix. In this hydrophobic/hydrophilic polymeric system, poly-(epsilon-caprolactone) maintained the integrity of the matrix, whereas polyethylene glycol 6000 dissolved from the matrix as the drug was released. Thus, the area-to-volume ratio of the device remained constant over the duration of the drug release. In vitro drug release studies were conducted at an ionic strength and pH as near as possible to those encountered in the rumen of cattle which generally varies from about 5.5 to 7.0. Drug release rates decreased as the matrix system:drug ratio increased. The drug release kinetics from these RRDs exhibit linearity with t(1/2) when the matrix was constituted with poly-(epsilon-caprolactone) and the release of the drug was determined as resulting from a diffusional mechanism following Higuchi's equation. When a part of the hydrophobic matrix was replaced with polyethylene glycol 6000 (5-15%), no linear correlation was observed with t(1/2) and the faster release of the drug was associated with the dissolution of the polyethylene glycol 6000. Complete dissolution of the drug at the typical pH encountered in the rumenal fluids and 39 degrees C would ensure good bioavailability of the drug following oral administration

Poly(ortho Esters) As Bioerodible Matrices for the Controlled Delivery of Pyrimethamine in Chemoprophylaxis of Malaria

Implants containing pyrimethamine were prepared from bioerodible poly(ortho esters). In vitro rate of drug release of physically entrapped pyrimethamine was examined as a function of the incorporated suberic acid. As found previously for other systems, increasing the concentration of suberic acid predictably increased rate of release of pyrimethamine. In vivo studies were carried out in rabbits to establish the pharmacokinetic profile and protection against Plasmodium berghei was carried out in a mouse model. Implants containing 21 wt% pyrimethamine and 5 wt% suberic acid provided protection for as long as three months

Controlled release of levamisole from poly-(epsilon-caprolactone) matrices .3. Effects of molecular weight and polymer coating on drug release

Rumino-reticulum devices (RRDs) (oral dosage forms allowing the release of a drug in the first part of the stomach of grazing animals during a prolonged time) in the form of cylindrical matrices were constructed to release orally anthelmintics in large animals during a period of 3-5 months. The aim of this study was to determine the influence of the molecular weight of the poly-(epsilon-caprolactone) (PCL) constituting the polymeric matrix and the influence of coatings on selected RRDs, The influence of the molecular weight and the coating on these RRDs were studied by the rate and the kinetic release of a model anthelmintic compound, levamisole hydrochloride. For the molecular weight, no significant differences (P > 0.05) were observed for matrix systems with a molecular weight of 101 100 or 147 000 Da. Conversely, a faster release (P < 0.05) was observed for a matrix with a molecular weight of 53 500 Da. Different kinetic release profiles of levamisole were achieved by application of coatings of poly-(epsilon-caprolactone), poly-(L-lactide) (PLA) and poly-(D,L-lactide-co-glycolide) (PLGA). While all coatings of PCL or PLGA reduced the release rate of the drug, only the coatings with PLA induced a lag time (similar to 15 days) before the release of the drug. The lag time encountered with PLA coatings was attributed to the crystallinity of the polymer. For the RRDs constructed with different molecular weights and those coated with PCL, fractional release as a function of time is shown to fit the Roseman-Higuchi model. Plots of (1 - F) ln(1 - F) + F are linear with time where F is the fraction of drug released at time t. In vitro drug release studies were conducted in conditions as near as possible to those encountered in vivo. Based on the typical pH encountered in vivo, complete release of the drug would ensure good bioavailability of the drug following oral administration. Copyright (C) 1996 Elsevier Science B.V