Synthesis,characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers

Copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with methyl methacrylate and styrene were synthesized in benzene at 85 °C in the presence of 2,2′‐azobisisobutyronitrile as initiator. The structure of the resulting copolymers was investigated and a polymerization mechanism was proposed. The intrinsic viscosity of the copolymers in dilute solutions of carbon tetrachloride was determined as a function of temperature and conformational transitions were investigated. Copyright © 2004 Society of Chemical Industry     

Comparison of conventional extraction under reflux conditions and microwave-assisted extraction of oil from popcorn.

Popcorn offers an environmentally friendly alternative to the commercial synthetic loose-fill packing materials. Popcorn could be used for cushioning purposes if the oil is extracted after the popping process. Conventional and microwave-assisted extraction methods were used for oil extraction from whole and ground, popped and unpopped kernels. The conventional extraction method achieved 68.5% oil recovery from whole popped kernels. However, whole unpopped kernels were not efficiently de-oiled with either of the methods. Extraction of oil from popped kernels is recommended; corn varieties with higher starch content and lower oil content should be used.     

Mother-child emotional availability in ecological perspective: Three countries, two regions, two genders.

This study used a cross-national framework to examine country, region, and gender differences in emotional availability (EA), a prominent index of mutual socioemotional adaptation in the parent-child dyad. Altogether 220 Argentine, Italian, and U.S. mothers and their daughters and sons from both rural and metropolitan areas took part in home observations when the children were 20 months old. In terms of country, Italian mothers were more sensitive and optimally structuring, and Italian children were more responsive and involving, than Argentine and U.S. dyads. In terms of region, rural mothers were more intrusive than metropolitan mothers, and boys from metropolitan areas were more responsive than boys from rural areas. In terms of gender, mothers of girls were more sensitive and optimally structuring than mothers of boys, and daughters were more responsive and involving than sons. Understanding how country, region, and gender influence EA exposes forces that shape child development, parent-infant interaction, and family systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A posteriori optimization of parameters in stabilized methods for convection–diffusion problems – Part I

Stabilized finite element methods for convection-dominated problems require the choice of appropriate stabilization parameters. From numerical analysis, often only their asymptotic values are known. This paper presents a general framework for optimizing stabilization parameters with respect to the minimization of a target functional. Exemplarily, this framework is applied to the SUPG finite element method and the minimization of a residual-based error estimator, an error indicator, and a functional including the crosswind derivative of the computed solution. Benefits of the basic approach are demonstrated by means of numerical results.     

Lack of predictive control in lifting series of virtual objects by individuals with diplegic cerebral palsy

To date, research on the motor control of hand function in cerebral palsy has focused on children with hemiplegia, although many persons with diplegic cerebral palsy (dCP) have asymmetrically decreased hand function. We explored the predictive capabilities of the motor system in a simple motor task of lifting a series of virtual objects for five persons with spastic dCP and five age-matched controls. When a person lifts an object, s/he uses an expectation of the weight of the object to generate a motor command. We asked the study subjects to lift a series of increasing weights and determined whether they extrapolated from past experience to predict the next weight in the series, even though that weight had never been experienced. Planning of precision grasp was assessed by measurement of the grip force at the beginning of the lifting task and by estimating the motor command. Execution of precision grasp was assessed by measurement of the time interval between the onset of grip and the onset of movement. We found that persons with dCP demonstrated a lack of predictive feed-forward control in their lifting movements: they exhibited a significantly longer time between onset of grip and onset of movement than the control subjects and they did not predict the weight of the next object in the lifting task. In addition, for subjects with dCP, the time between the onset of grip and the onset of movement of the dominant hand correlated strongly with the outcome of a hand function test. We postulate that a higher-order motor planning deficit in addition to execution deficit are evident in the subjects with spastic diplegic.     

SN-38 loading capacity of hydrophobic polymer blend nanoparticles: formulation,optimization and efficacy evaluation

One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers. D-optimal design was applied to optimize PLGA/PCL ratio in the polymer blend and the mode of addition of the amphiphilic copolymer Lutrol^®F127 in order to maximize SN-38 loading and obtain NPs with acceptable size for passive tumor targeting. Drug/polymer and polymer/polymer interaction analysis pointed to high degree of compatibility and miscibility among both hydrophobic polymers, providing core configuration with higher drug loading capacity. Toxicity studies outlined the biocompatibility of the blank NPs. Increased in vitro efficacy of drug-loaded NPs compared to the free drug was confirmed by growth inhibition studies using SW-480 cell line. Additionally, the optimized NP formulation showed very promising blood circulation profile with elimination half-time of 7.4?h.     

Multifunctional Bioinstructive 3D Architectures to Modulate Cellular Behavior

Biological structures control cell behavior via physical, chemical, electrical, and mechanical cues. Approaches that allow us to build devices that mimic these cues in a combinatorial way are lacking due to there being no suitable instructive materials and limited manufacturing procedures. This challenge is addressed by developing a new conductive composite material, allowing for the fabrication of 3D biomimetic structures in a single manufacturing method based on two‐photon polymerization. The approach induces a combinatorial biostimulative input that can be tailored to a specific application. Development of the 3D architecture is performed with a chemically actuating photocurable acrylate previously identified for cardiomyocyte attachment. The material is made conductive by impregnation with multiwalled carbon nanotubes. The bioinstructive effect of 3D nano‐ and microtopography is combined with electrical stimulation, incorporating biochemical, and electromechanical cues to stimulate cells in serum‐free media. The manufactured architecture is combined with cardiomyocytes derived from human pluripotent stem cells. It is demonstrated that by mimicking biological occurring cues, cardiomyocyte behavior can be modulated. This represents a step change in the ability to manufacture 3D multifunctional biomimetic modulatory architectures. This platform technology has implications in areas spanning regenerative medicine, tissue engineering to biosensing, and may lead to more accurate models for predicting toxicity.     

Linear optimal control strategies for production systems with a discrete-event demand pattern

A class of production systems are considered in this paper with the aim of determining closed-loop strategies providing the production effort as functions of the system state. The key feature of the considered class of systems is that the demand and the way it is satisfied are asynchronous sequences of part requests and instantaneous withdrawals, respectively, generated by discrete-event processes, whereas the production process has continuous-time dynamics. The optimization problem, whose objective is to minimize inventory and lateness costs, is restated as an optimal control problem by exploiting some structural properties of the optimal solution. Then, optimal closed-loop strategies are found with dynamic programming techniques.     

Tracing Hidden Herbivores: Time-Resolved Non-Invasive Analysis of Belowground Volatiles by Proton-Transfer-Reaction Mass Spectrometry (PTR-MS)

Root herbivores are notoriously difficult to study, as they feed hidden in the soil. However, root herbivores may be traced by analyzing specific volatile organic compounds (VOCs) that are produced by damaged roots. These VOCs not only support parasitoids in the localization of their host, but also may help scientists study belowground plant-herbivore interactions. Herbivore-induced VOCs are usually analyzed by gas-chromatography mass spectrometry (GC-MS), but with this off-line method, the gases of interest need to be preconcentrated, and destructive sampling is required to assess the level of damage to the roots. In contrast to this, proton-transfer-reaction mass spectrometry (PTR-MS) is a very sensitive on-line, non-invasive method. PTR-MS already has been successfully applied to analyze VOCs produced by aboveground (infested) plant parts. In this review, we provide a brief overview of PTR-MS and illustrate how this technology can be applied to detect specific root-herbivore induced VOCs from Brassica plants. We also specify the advantages and disadvantages of PTR-MS analyses and new technological developments to overcome their limitations.