A study of aromatic polyester/chlorinated polymer blends

A large number of studies have been devoted in recent years to the miscibility behavior of linear polyesters with chlorinated polymers, including poly(vinyl chloride) (PVC), chlorinated PVC, chlorinated poly(ethylenes), and copolymers of vinylidene chloride (Saran). However, similar studies with aromatic polyesters are lacking. It is the purpose of this paper to compare the properties of blends made of poly(ethylene terephthalate), poly(butylene terephthalate) or poly(hexamethylene terephthalate) and of various chlorinated polymers. It is shown that a high concentration of chlorine atoms is required to achieve miscibility. Moreover, there is a “miscibility window” in terms of the carbonyl concentration of polyesters, immiscibility being found for carbonyl concentrations outside this window, A similar behavior was observed before for linear polyester/chlorinated polymer blends and for polyester/polycarbonate blends. Solid state small-angle light scattering experiments were also conducted to follow the morphology of the blends as a function of composition. Spherulites were found but their size vary with composition.     

Porous protein-based scaffolds prepared through freezing as potential scaffolds for tissue engineering

Successful tissue engineering with the aid of a polymer scaffold offers the possibility to produce a larger construct and to mould the shape after the defect. We investigated the use of cryogelation to form protein-based scaffolds through different types of formation mechanisms; enzymatic crosslinking, chemical crosslinking, and non-covalent interactions. Casein was found to best suited for enzymatic crosslinking, gelatin for chemical crosslinking, and ovalbumin for non-covalent interactions. Fibroblasts and myoblasts were used to evaluate the cryogels for tissue engineering purposes. The stability of the cryogels over time in culture differed depending on formation mechanism. Casein cryogels showed best potential to be used in skeletal tissue engineering, whereas gelatin cryogels would be more suitable for compliable soft tissues even though it also seemed to support a myogenic phenotype. Ovalbumin cryogels would be better suited for elastic tissues with faster regeneration properties due to its faster degradation time. Overall, the cryogelation technique offers a fast, cheap and reproducible way of creating porous scaffolds from proteins without the use of toxic compounds.     

Chemical warfare and survival strategies in bacterial range expansions

Dispersal of species is a fundamental ecological process in the evolution and maintenance of biodiversity. Limited control over ecological parameters has hindered progress in understanding of what enables species to colonize new areas, as well as the importance of interspecies interactions. Such control is necessary to construct reliable mathematical models of ecosystems. In our work, we studied dispersal in the context of bacterial range expansions and identified the major determinants of species coexistence for a bacterial model system of three Escherichia coli strains (toxin-producing, sensitive and resistant). Genetic engineering allowed us to tune strain growth rates and to design different ecological scenarios (cyclic and hierarchical). We found that coexistence of all strains depended on three strongly interdependent factors: composition of inoculum, relative strain growth rates and effective toxin range. Robust agreement between our experiments and a thoroughly calibrated computational model enabled us to extrapolate these intricate interdependencies in terms of phenomenological biodiversity laws. Our mathematical analysis also suggested that cyclic dominance between strains is not a prerequisite for coexistence in competitive range expansions. Instead, robust three-strain coexistence required a balance between growth rates and either a reduced initial ratio of the toxin-producing strain, or a sufficiently short toxin range.     

Histone Deacetylase 2 (HDAC2) Inhibitors Containing Boron

Histone deacetylase enzymes (HDACs) are responsible for the global silencing of tumour-suppressor genes. Treatment with a histone deacetylase inhibitor (HDACi) can reverse this process and restore normal cell function. Herein, we report a small series of boron-based (boronic acid, boronate ester and closo-1,2-carborane) HDAC2 inhibitors with IC₅₀ values in the nanomolar range. The boronate ester 4 b was the most potent compound assessed in this study (IC₅₀=40.6±1.5 nM), followed closely by the 1,2-closo-carborane (IC₅₀=42.9±1.5 nM). Compound 4 b exceeds the potency of the related gold-standard HDAC pan-inhibitor vorinostat ( 1 ) toward this particular HDAC isoform.     

Reported Use of Reduced-sugar Foods and Beverages Reflect High-quality Diets

ABSTRACT: The purpose of this study was to determine differences in nutrient and energy intakes and in quantity of food eaten, and to compare the knowledge, attitudes, and practices of users of reduced-sugars foods and beverages with those who use only the full sugar versions of the same products. Records for adults (≥ 20 y old) responding to the 1994–1996 Continuing Survey of Food Intakes by Individuals (CSFII) and the Diet Health and Knowledge Survey were used. CSFII food lists were scanned for both full and reduced-sugar versions of yogurt, cocoa, and other milk beverages, frozen and gelatin desserts, puddings, breads, cookies, cakes, fruit drinks, carbonated and noncarbonated drinks, confectionary products, and sweeteners. Recalls were sorted for those reporting use of only full sugar (FS) products and those reporting mixed use of full sugar and reduced-sugar (RS) versions. Comparisons were made between demographic characteristics, body mass index, food group servings, food intake amounts, and nutrient densities. When compared with FS users, RS users consistently reported significantly higher intakes of fruit, lower intakes of discretionary fat and added sugars, and equal or lower intakes of other foods (in gram amounts), except for greater intake of yogurt and frozen and gelatin desserts. RS users tended to report similar or higher micronutrient intakes compared with FS users. After adjusting for energy intake, significantly higher micronutrient intakes were found for both males and females consuming RS foods and beverages (13 and 15 of 17 nutrients, respectively).     

A multiple-layer finite-element model of the surface EMG signal

The effect of skin, muscle, fat, and bone tissue on simulated surface electromyographic (EMG) signals was examined using a finite-element model. The amplitude and frequency content of the surface potential were observed to increase when the outer layer of a homogeneous muscle model was replaced with highly resistive skin or fat tissue. The rate at which the surface potential decreased as the fiber was moved deeper within the muscle also increased. Similarly, the rate at which the surface potential decayed around the surface of the model, for a constant fiber depth, increased. When layers of subcutaneous fat of increasing thickness were then added to the model, EMG amplitude, frequency content, and the rate of decay of the surface EMG signal around the limb decreased, due to the increased distance between the electrodes and the active fiber. The influence of bone on the surface potential was observed to vary considerably, depending on its location. When located close to the surface of the volume conductor, the surface EMG signal between the bone and the source and directly over the bone increased, accompanied by a slight decrease on the side of the bone distal to the active fiber. The results emphasize the importance of distinguishing between the effects of material properties and the distance between source and electrode when considering the influence of subcutaneous tissue, and suggest possible distortions in the surface EMG signal in regions where a bone is located close to the skin surface.     

Effect of the licensing process on hygiene in retail butchers' premises in the West Midlands,United Kingdom

As the result of a change in legislation, all retail butchers in England were required to be licensed by 1 November 2000. A fully implemented hazard analysis critical control point plan was a condition of the license. This longitudinal study assessed the effect of licensing on hygiene in a group of retail butchers in the West Midlands, England. A hygiene audit and environmental sampling were used to determine if the licensing process improved hygiene in the study group. At the end of the study, 30% of the original group were no longer trading as they had been, having either altered the product they were selling or ceased to trade. The remaining butchers showed a significant improvement in the hygiene of their premises, both in the audit scores and in the environmental sampling. The mean audit score for the group had improved from an initial score of 47.54 to 54.95 (P < 0.02). The contamination with Enterobacteriaceae on equipment used for cooked meat had also improved, decreasing from mean contamination levels of 1.38 log CFU/cm2 before licensing to mean contamination levels of -0.11 log CFU/cm2 after licensing (P < 0.00001).     

Skin cancer detection by spectroscopic oblique-incidence reflectometry: classification and physiological origins

Data obtained from 102 skin lesions in vivo by spectroscopic oblique-incidence reflectometry were analyzed. The participating physicians initially divided the skin lesions into two visually distinguishable groups based on the lesions' melanocytic conditions. Group 1 consisted of the following two cancerous and benign subgroups: (1) basal cell carcinomas and squamous cell carcinomas and (2) benign actinic keratoses, seborrheic keratoses, and warts. Group 2 consisted of (1) dysplastic nevi and (2) benign common nevi. For each group, a bootstrap-based Bayes classifier was designed to separate the benign from the dysplastic or cancerous tissues. A genetic algorithm was then used to obtain the most effective combination of spatiospectral features for each classifier. The classifiers, tested with prospective blind studies, reached statistical accuracies of 100% and 95% for groups 1 and 2, respectively. Properties that related to cell-nuclear size, to the concentration of oxyhemoglobin, and to the concentration of deoxyhemoglobin as well as the derived concentration of total hemoglobin and oxygen saturation were defined to explain the origins of the classification outcomes.     

Standardized low-load repetitive work: evidence of different motor control strategies between experienced workers and a reference group

The purpose of this laboratory study was to evaluate the possible differences in motor strategies to a new standardized low-load repetitive work task in between healthy experienced workers and a reference group. Work task event duration, i.e. working rhythm, cutting forces, surface electromyographic (EMG) activity from four shoulder muscles, postural activity, and arm and trunk movements in 3D were recorded during low-load repetitive work simulation. The experienced group showed lower EMG activity and frequency contents (P<0.05), more abducted position of the upper arm and forward flexion of the trunk prior to work simulation (P<0.05), and increased arm and trunk range of motion (P<0.05) compared with the reference group. The results highlight that experienced butchers have a different motor strategy compared with a reference group, i.e. more variable form of coordination pattern. Furthermore, the initial implementation of a possible protective motor strategy by experienced workers might be a very important prognostic factor.