Benefits in the Macrophage Response Due to Graphene Oxide Reduction by Thermal Treatment

Graphene and its derivatives are very promising nanomaterials for biomedical applications and are proving to be very useful for the preparation of scaffolds for tissue repair. The response of immune cells to these graphene-based materials (GBM) appears to be critical in promoting regeneration, thus, the study of this response is essential before they are used to prepare any type of scaffold. Another relevant factor is the variability of the GBM surface chemistry, namely the type and quantity of oxygen functional groups, which may have an important effect on cell behavior. The response of RAW-264.7 macrophages to graphene oxide (GO) and two types of reduced GO, rGO15 and rGO30, obtained after vacuum-assisted thermal treatment of 15 and 30 min, respectively, was evaluated by analyzing the uptake of these nanostructures, the intracellular content of reactive oxygen species, and specific markers of the proinflammatory M1 phenotype, such as CD80 expression and secretion of inflammatory cytokines TNF-α and IL-6. Our results demonstrate that GO reduction resulted in a decrease of both oxidative stress and proinflammatory cytokine secretion, significantly improving its biocompatibility and potential for the preparation of 3D scaffolds able of triggering the appropriate immune response for tissue regeneration.     

Rheology of liquid foods under shear flow conditions: Recently used models

Proper modeling of flow or viscosity curves as a function of shear rate is a useful tool in any engineering activity. The rheology of foods depends on the composition, processing to which they have been subjected and the state of dispersion in which they are found. Liquid foods are complex biosystems, that show non-Newtonian behavior under flow conditions. This review presents models used in recent decades to describe the experimental rheological behavior of various liquid foods, ranging from Newtonian fluids to the most complex. Some non-Newtonian parameters such as those of the Ostwald-de Waele, Bingham, Herschel–Bulkley, Casson, Cross, and Carreau models are summarized. Examples of thixotropic behavior described by the Weltman and Abu-Jdayil models are also presented. In each model, explanations based on the composition and dispersion state of the food are made. This is useful in innovative processing technologies and for scientists new to the field of food rheology. An attempt is made to exemplify and group the expected behavior for most fluid foods, including some for a dysphagia diet, depending on their composition or the dispersed system formed, which will be useful for professionals who wish to compare reported rheological parameters with those obtained experimentally.     

Geometric optimization of a thermoacoustic regenerator

This work illustrates the optimization of thermoacoustic systems, while taking into account thermal losses to the surroundings that are typically disregarded. A simple thermoacoustic engine is used as an example for the methodology. Its driving component, the thermoacoustic regenerator (also referred to as the stack), is modeled with a finite element method and its dimensions are varied to find an optimal design with regard to thermal losses. Thermoacoustic phenomena are included by considering acoustic power, and viscous and capacitive losses that are characteristic for the regenerator. The optimization considers four weighted objectives and is conducted with the Nelder–Mead Simplex method. When trying to minimize thermal losses, the presented results show that the regenerator should be designed to be as short as possible. It was found that there is an optimal regenerator diameter for a given length. The results are presented for a variety of materials and weights for each objective.     

Misreading liberalisation and privatisation: The case of the US energy utilities in Europe

In response to energy market liberalisation and privatisation initiatives promoted by the EU and other European states in the 1990s, a large number of US energy utilities expanded their activities in Europe, mainly through acquisitions. The size of their investment was, a decade later, matched by the ensuing scale of their retreat, wealth destruction and often forced exit. Combining interviews, industry studies, published financial data and company reports, this article examines critically their strategy and, in light of widespread failures, seeks to answer the question of what went wrong. It is argued that mistakes might have been avoided through greater appreciation of how market liberalisation evolves given changing government priorities and general sovereign risk.     

Poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid): synthesis,physico-chemical characterisation and nafcillin carrier

In the present study polymeric microbeads of poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid) or p(HEMA-co-dDMA-co-AA) were synthesised and characterized through FT-IR and scanning electron microscopy (SEM); their swelling behavior against saline solution was explored and their in vitro cytotoxicity was evaluated. Further, in order to elucidate kinetic aspects regarding the ternary system p(HEMA-co-dDMA-co-AA), a mathematical model of the reactivity ratios of the comonomers in the terpolymer has been conceived and analyzed. An intensified tendency of AA units accumulation in the copolymer has been noticed, in spite of HEMA units, while dDMA conserves in the copolymer the fraction from the feed. Three compositions have been selected for nafcillin-loading and their in vitro release capacity was evaluated. The compositions of 80:10:10 and 75:10:15 M ratios appear suitable for further in vivo testing, in order to be used as drug delivery systems in the treatment of different osseous diseases.     

Effects of adolescent nicotine exposure on opioid consumption and neuroendocrine response in adult male and female rats.

Effects of adolescent nicotine exposure on illicit drug consumption and neuroendocrine functioning were examined in adult rats. Nicotine (NIC; 2 doses) or saline (SAL) was administered via osmotic minipumps to 30 male and 30 female adolescent Wistar rats for 19 days. After NIC/SAL cessation, oral opioid consumption was assessed in the home cage for 4 weeks. Plasma corticosterone and ACTH were measured at the end of the experiment. Low-NIC male rats consumed more fentanyl than did high-NIC male rats; opioid consumption among adult female rats was not altered by NIC exposure. Females consumed more fentanyl than did males, regardless of NIC history. NIC exposure increased adult corticosterone and ACTH levels in a dose-dependent manner. Results suggest important effects of adolescent NIC exposure, including altered neuroendocrine status and opioid consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sintering of Industrial Mullites in the Presence of Magnesia as a Sintering Aid

The sinterability of two industrial mullite powders, in the presence of MgO as a sintering aid, was investigated. A glassy phase, which was generated during preparation, was present in both powders; this glassy phase had a strong influence on sintering, depending on its content, composition, and spatial distribution. MgO promoted sintering in the presence of a liquid phase, both in the as-received materials and in samples washed with HF, in which most of the pre-existing glassy phase was eliminated. Investigations using transmission electron microscopy, coupled with energy-dispersive spectroscopy, as well as dilatometric measurements and X-ray diffraction data, on washed and unwashed materials and on quenched and slow-cooled samples allowed a better understanding of the influence of MgO and the glassy phase on the sintering behavior and the formation of new phases. Most of the phases, in fact, can be explained by using the MgO–Al₂O₃–SiO₂ phase diagram, even in such complex systems.     

Modeling Storm-Water Runoff Quantity and Quality from Marine Drydocks

Storm-water runoff from a floating marine drydock can be a major source of pollution for the waterway in which the drydock is located. Significant amounts of pollutants build up over drydock surfaces because of intensive industrial activity. During periods of rainfall these pollutants can be washed off and quickly transported into the receiving water. In this study, a mathematical model has been developed to simulate the quantity and quality of storm-water runoff from marine drydocks. The mathematical model is based on the two-dimensional kinematic-wave and convective transport equations for total suspended solids. An empirical formula is used to model the wash-off process. An implicit finite-difference scheme is employed to solve the governing equations of the model numerically. In support of the modeling effort, the quantity and quality of storm-water runoff from a private drydock was monitored under actual rainfall-runoff conditions. The samples collected were analyzed in the laboratory to determine the pollutant loading of the runoff, and these data were subsequently used to calibrate and verify the mathematical model.     

Using information, motivational enhancement, and skills training to reduce the risk of HIV infection for low-income urban women: A second randomized clinical trial.

This randomized clinical trial evaluated an HIV-risk reduction (HIV-RR) intervention based on the information–motivation–behavioral skills model. At baseline, 102 women (M age?=?29 years; 88% African American) completed a survey regarding HIV-related knowledge, risk perceptions, behavioral intentions, and risk behavior. Participants were then assigned to either the HIV-RR intervention or a health-promotion control group. Postintervention and follow-up data indicated that women in the HIV-RR program enhanced their knowledge and strengthened their risk reduction intentions relative to controls. Moreover, HIV-RR women who expressed "imperfect" intentions also increased their condom use, talked more with partners about condom use and HIV testing, and were more likely to have refused unprotected sex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)