Characterisation of northern Patagonian bentonites for pharmaceutical uses

This paper evaluates the suitability of some smectite-rich samples from northern Patagonia (Argentina) for pharmaceutical use. The clays must comply with some general features before considering their use in pharmacy, including high mineral and chemical purity and the absence of microbial pathogens. Specific characteristics such as sediment volume, swelling power and gel formation are also important for particular applications such as their use as suspending agent. The mineralogical and chemical compositions of the samples are typical of bentonites, mainly consisting of montmorillonite. Considering the requisites of major pharmacopoeias for the use of silicates in pharmacy and taking into account the microbiological results, we could designate a pharmaceutically acceptable denomination for all samples, although some of them might need removal of quartz. The chemical, textural and porosimetric properties showed some differences between the samples that would affect their particular technical properties as pharmaceutical excipients. The samples could be used in pharmacy for topical applications as suspending agent. Regarding their use as adsorbents, specific sorption studies could help to discriminate their usefulness, as suggested by their high CEC values.     

Adding support for high-level skeletal animation

We present a data structure specially geared toward the definition and management of synthetic actors in real-time computer graphics. The relation between our proposed data structure and the Silicon Graphics API Performer® makes its implementation possible on a low-cost real-time platform thanks to current accelerating cards. We demonstrate how our data structure is used to generate motion by means of two different applications. Both of them make use of direct and inverse kinematics and may use motion capture. ARTgraph is a development environment devoted to the creation of high-quality real-time 3D-graphics applications (basically, 3D games) and the ALVW system is a general platform that provides and coordinates a sensing-analysis-acting loop to provide behavior for synthetic actors in their own scenario. The aim of this paper is to contribute to the standardization process of multiplatform synthetic actor programs or libraries     

Role of amine activators on the curing parameters,properties and toxicity of acrylic bone cements

A review about the accelerating effect of tertiary aromatic amines used as activator in the benzoyl peroxide/amine system for the curing of acrylic resins is presented. The kinetics, mechanism and activation energy of the reaction are considered, together with some toxicity, residuals and leaching data concerned with biomedical applications of this system, e.g. denture resins or acrylic bone cements. Furthermore, some results relating the effect of the temperature of the surroundings on the curing parameters of the cements prepared with three amines (N,N-dimethyl-4-toluidine, N,N-dimethylbenzyl alcohol and N,N-dimethylbenzyl methacrylate) are shown. The results indicate that the temperature has a significant effect on the curing parameters, and must be considered in the evaluation of new activators. The relevance of these results lies with the importance of thermal trauma generally associated with the implantation of acrylic bone cements. © 1998 SCI.     

Morphology,Thermal Stability,and Mechanical Behavior of [Poly(propylene)‐grafted Maleic Anhydride]‐Layered Expanded Graphite Oxide Composites

PP‐g‐MA‐layered EGO composites were prepared directly by solution blending. Two types of PP‐g‐MA/EGO composites were prepared using different mixing methods: distributive and dispersive. In this study, the effects of the mixing method of EGO on the crystalline structure and thermo‐mechanical properties of PP‐g‐MA/EGO composites are reported. WAXD exhibited a shift in 2θ of the monoclinic (α) phase of PP‐g‐MA and (002) EGO peaks for PP‐g‐MA/EGO layered composites, which indicated a modification of the crystalline structure of PP‐g‐MA in the layered composites. DSC exhibited a single characteristic melting peak of monoclinic (α) crystalline phase PP‐g‐MA. The incorporation of EGO increased T_c indicating that the EGO acted as a nucleating agent for PP‐g‐MA. The crystallinity of the PP‐g‐MA/EGO composites was found to be dependent on the mixing method. Thermogravimetry demonstrated that PP‐g‐MA in the presence of EGO has higher degradation temperature, suggesting that the graphite particles acted as a thermal barrier material for PP‐g‐MA. DMA indicated that incorporation of EGO into PP‐g‐MA increased the storage modulus, due to the hydrogen bonding between EGO and MA of PP‐g‐MA.

     

Aqueous phase disinfection with power ultrasound: process kinetics and effect of solid catalysts

The effectiveness of power ultrasound as a viable alternative for destroying pathogenic organisms in homogeneous and heterogeneous mixtures of aqueous solutions was investigated. The method involved monitoring of total coliform bacteria during sonication of E. coli suspensions in the absence and presence of equivalent mass concentrations of ceramic, metallic zinc, and activated carbon. It was found that disinfection by ultrasound is accelerated with solids in the order activated carbon > ceramic > metallic zinc. Process kinetics for each test system were assessed by nonlinear regression analysis of bacterial density vs time data, and the predicted model was found to resemble a well-known expression describing chlorination kinetics. The model denoted that in the presence of activated carbon the process rate was pseudo first order, and the required contact time to accomplish 50% kill was 2.8, 2.4, and 4 times shorter than it was in the zinc-catalyzed, ceramic-catalyzed, and noncatalyzed systems, respectively. It was further found that catalytic effects faded away with increased sonication time and/or reduced number of bacteria, denoting (i) decreased probability of bacterial contact with the solid-liquid interface; (ii) erosion of solid surfaces by vibrational effects; and (iii) reduced cavity formation due to degassing effects of ultrasound.     

Quality and Nutritional Status of Fresh-Cut Tomato as Affected by Spraying of Delactosed Whey Permeate Compared to Industrial Washing Treatment

The aim of this study was to examine the applicability of delactosed whey permeate (DWP) treatment on preserving the quality and antioxidant attributes of fresh-cut tomato. Tomatoes were treated with 3% DWP by dipping, spraying and a combination of both, stored at 4?°C for 10?days and compared with the industrial standard, chlorine. The combination of dipping and spraying of DWP showed the best results for all the markers tested. The combined treatment of dipping and spraying of DWP significantly lowered total counts (??1.0 log cfu/g), yeast and moulds (??1.2 log cfu/g), inhibited the loss of firmness (25%) and reduced POD activity (15%) of the tomato slices after 10?days compared to the chlorine treatment. Moreover, DWP-treated tomatoes maintained significantly (p?<?0.05) higher levels of vitamin C, total phenols and antioxidant activity (DPPH) than the chlorine-treated samples during storage. Sensory scores confirmed that DWP-treated tomatoes retained better aroma and texture. Also, the appearance and overall acceptability were higher than chlorine-treated tomatoes. Thus DWP treatment has potential to extend the shelf life of fresh-cut tomatoes.     

Comparison of numerical and experimental performance criteria of an ammonia–water bubble absorber using plate heat exchangers

A mathematical model for ammonia–water bubble absorbers was developed and compared with experimental data using a plate heat exchanger. The analysis was performed carrying out a sensitive study of selected operation parameters on the absorber thermal load and mass absorption flux. Regarding the experimental data, the values obtained for the solution heat transfer were in the range 0.51–1.21 kW m^?2 K^?1 and those of the mass absorption flux in the range 2.5–5.0 × 10^?3 kg m^?2 s^?1. The comparison between experimental and simulation results was acceptable being the maximum difference of 11.1% and 28.4% for the absorber thermal load and the mass absorption flux, respectively.     

Effects of different cooking methods on chemical compositions,in vitro starch digestibility and antioxidant activity of taro (Colocasia esculenta) corms

The impacts of different cooking methods (boiling, steaming, baking, microwaving and frying) on chemical compositions, starch digestibility and antioxidant activity of taro corms were investigated. Compared with raw taro, boiling and frying reduced crude protein and ash contents. Frying significantly increased crude fat and fibre contents but decreased carbohydrate content. All cooking methods reduced oxalate content, especially frying. Among the cooked products, the boiled taro had the highest rapidly digestible starch (RDS) but the lowest resistant starch (RS) contents. In contrast, the fried taro provided the lowest RDS but the highest RS contents. All cooking methods reduced the total phenolic content and antioxidant activity of taro. The boiled taro had the lowest antioxidant activity but the fired taro provided the highest. Frying was able to retain most of the health-promoting compounds with the lowest oxalate content; however, the high consumption of high-fat fried taro may adversely affect human health.     

Real-Time Imaging with Frequency Scanning Array Antenna for Industrial Inspection Applications at W band

A real-time imaging system based on a frequency scanning antenna for conveyor belt setups is presented in this paper. The frequency scanning antenna together with an inexpensive parabolic reflector operates at the W band enabling the detection of details with dimensions in the order of 2 mm. In addition, a low level of sidelobes is achieved by optimizing unequal dividers to window the power distribution for sidelobe reduction. Furthermore, the quality of the images is enhanced by the radiation pattern properties. The performance of the system is validated by showing simulation as well as experimental results obtained in real time, proving the feasibility of these kinds of frequency scanning antennas for cost-effective imaging applications.