A New Hand-Held Microsystem Architecture for Biological Analysis

This paper presents a hand-held microsystem based on new fully integrated magnetoresistive biochips for biomolecular recognition (DNA hybridization, antibody antigen interaction, etc.). Magnetoresistive chip surfaces are chemically treated, enabling the immobilization of probe biomolecules such as DNA or antibodies. Fluid handling is also integrated in the biochip. The proposed microsystem not only integrates the biochip, which is an array of 16times16 magnetoresistive sensors, but it also provides all the electronic circuitry for addressing and reading out each transducer. The proposed architecture and circuits were specifically designed for achieving a compact, programmable and portable microsystem. The microsystem also integrates a hand-held analyzer connected through a wireless channel. A prototype of the system was already developed and detection of magnetic nanoparticles was obtained. This indicates that the system may be used for magnetic label based bioassays     

Optimal cross-section and configuration design of elastic-plastic structures subject to dynamic cyclic loading

This paper shows an optimal design problem with continuum variational formulation, applied to nonlinear elasticplastic structures subject to dynamic loading. The total Lagrangian procedure is used to describe the response of the structure. The direct differentiation method is used to obtain the sensitivities of the structural response that are needed to solve the optimization problem. Since unloading and reloading of the structure are allowed, the structural response is path-dependent and an additional step is needed to integrate the constitutive equations. It can be shown, consequently, that design sensitivity analysis is also path-dependent. A finite element method with implicit time integration is used to discretize the state and sensitivity equations.A mathematical programming approach is used for the optimization process. Numerical applications are performed on a 3-D truss structure, where cross-sectional areas and nodal point coordinates are treated as design variables. Optimal designs have been obtained and compared by using two different strategies: a twolevel strategy where the levels are defined according to the type of design variables, cross sectional areas or node coordinates, and optimizing simultaneously with respect to both types of design variables. Comparisons have also been made between optimal designs obtained by considering or not considering the inertial term of the structural equilibrium.     

Equivariant adaptive source separation

Source separation consists of recovering a set of independent signals when only mixtures with unknown coefficients are observed. This paper introduces a class of adaptive algorithms for source separation that implements an adaptive version of equivariant estimation and is henceforth called equivariant adaptive separation via independence (EASI). The EASI algorithms are based on the idea of serial updating. This specific form of matrix updates systematically yields algorithms with a simple structure for both real and complex mixtures. Most importantly, the performance of an EASI algorithm does not depend on the mixing matrix. In particular, convergence rates, stability conditions, and interference rejection levels depend only on the (normalized) distributions of the source signals. Closed-form expressions of these quantities are given via an asymptotic performance analysis. The theme of equivariance is stressed throughout the paper. The source separation problem has an underlying multiplicative structure. The parameter space forms a (matrix) multiplicative group. We explore the (favorable) consequences of this fact on implementation, performance, and optimization of EASI algorithms     

Short communication: Verifying Holstein heifer heart girth to body weight prediction equations

The estimation of Holstein heifer body weight (BW) from heart girth measurements is needed, as many farms do not have animal scales to make the management decisions that require BW. The correlation between heart girth and BW is known to vary with differing animal conformation. The previous equation to correlate the 2 measures for Holstein dairy heifers was done 25 yr ago. Data were derived from 6 US experiment stations that are part of Regional Research Project NC-2042: Management Systems to Improve the Economic and Environmental Sustainability of Dairy Enterprises. After deriving a new equation from a data set of observations and using a second validation data set, it was determined that the equation developed in 1992 was still valid and further equation development was not needed at this time.     

Nutritional composition of the meat of Hereford and Braford steers finished on pastures or in a feedlot in southern Brazil

Chemical and mineral composition and the intramuscular fatty acid (IMF) profile of the Longissimus dorsi muscle (LM) of 60 purebred Hereford, 1/4 Braford and 3/8 Braford steers finished either in a feedlot or on improved pastures of the Pampa biome were evaluated. Pastures were improved with the introduction of Lolium multiflorum, Trifolium repens, and Lotus corniculatus. On average, beef from pasture-fed steers presented higher concentrations of the fatty acids C18:3n − 3 (P < 0.001), C20:3n − 3 (P = 0.035), total n − 3 (P < 0.001) and lower n − 6/n − 3 ratio (P < 0.001) in the IMF, and higher Mg and lower K content in muscle relative to those finished in the feedlot. C12:0 concentration in IMF was higher (P = 0.027) for 3/8 Braford than the purebred Hereford steers, whereas purebred Herefords presented lower C14:1 (P = 0.003) and higher C18:0 (P = 0.022) concentrations than the two Braford groups. The meat composition of purebred Hereford and Braford steers was not substantially different; however, beef produced exclusively on improved pastures presented higher concentration of components that are considered beneficial to human health, such as n − 3 fatty acids, and a lower n − 6/n − 3 ratio.     

An assessment of energy benefits of efficient household air-conditioners in Brazil

Increasing efficiency of electrical equipment is essential to national energy rationality, enabling energy consumption reduction and postponing inversion in distribution, transmission and generation, as well as mitigating environmental impacts associated with such activities. Considering such purposes, two actions have been promoted in Brazil: (a) minimum energy performance standards (MEPS) have been required for some appliances and (b) consumers have been informed about the most efficient products by ??endorsement labeling.?? The purpose of this study is to assess window and split air-conditioners with Brazilian MEPS. To evaluate the impact of efficient air-conditioners in this market, a model was developed based on estimates for quantity of equipment in operation and unitary consumption, as determined by local temperature records. From this model, it was deduced that using only efficient conditioners (class A for Brazilian Labeling Program/INMETRO, with PROCEL Label) an annual saving of 322?GWh and a reduction in demand of 109?MW could be obtained in 2007. Furthermore, it was observed that the current MEPS established by Brazilian legislation for air-conditioners may be considered relatively low. Considering that MEPS are similar to those observed in China (the main exporter of air-conditioners to the Brazil), an energy saving of roughly 222?GWh could be achieved in the same year. Impacts on emission of greenhouse gases are also estimated.     

Views of dairy farmers,agricultural advisors,and lay citizens on the ideal dairy farm

The aim of this qualitative study was to explore the shared and divergent views among Brazilian dairy farmers, agricultural advisors, and lay citizens on what characteristics they viewed were most important on an ideal dairy farm. Responses from 107 dairy farmers, 170 agricultural advisors (including veterinarians), and 280 lay citizens were subjected to thematic analyses. Five themes were identified: milk quality, animal welfare, economics, society, and the environment. Although all 3 groups made reference to each of the 5 themes, they emphasized different characteristics. The lay citizens placed the most emphasis on milk quality. In contrast, both the farmers and the advisors highlighted economics as the most important characteristic of an ideal dairy farm. When considering only animal welfare, we noted differences in the use of the constructs of animal welfare: farmers and advisors referred mostly to aspects related to biological functioning, whereas lay citizens emphasized affective states and naturalness. All 3 stakeholder groups referred to the use of pasture as being an important component of an ideal dairy farm but again differed in their reasons; citizens referred to pasture in the context of naturalness, whereas the other 2 stakeholder groups almost always referred to pasture using economic terms. Technology was highlighted by all 3 groups as an important characteristic of an ideal dairy farm but differences were noted in their justification for this view. For example, lay citizens viewed technology as a tool to improve milk quality, whereas farmers and advisors both referred to technology as an important vehicle to improve quality of life for those working in the industry. Lay citizens raised several concerns associated with the overuse of antibiotics and other chemicals, but farmers and advisors rarely mentioned these types of concerns. The latter 2 stakeholders placed considerable emphasis on the quality of life of dairy farmers and workers, an issue rarely discussed by lay citizens. Overall, our findings highlight several disconnects between the expectations of the lay citizens, and farmers and their advisors. We suggest that dairy farmers and agricultural advisors should both reflect on the desires of the lay public in what they view to be an ideal dairy farm, as this may help bridge some of the current disconnects.     

Anti-inflammatory effect of aqueous extracts of roasted and green Coffea arabica L.

Green coffee contains a large quantity and variety of polyphenols and flavonoids. The roasting affects the composition of the polyphenols in coffee, due to the formation of compounds generated by Maillard reaction, which can have anti-inflammatory or antioxidant potential. The anti-inflammatory and antioxidant effects of aqueous extracts of green (AGCa) and roasted (ARCa) coffee beans were investigated in animal models and using a DPPH radical scavenging test. In the formalin test the extracts reduced licking activity only in the late phase. The inhibitory values of oedema at 3 h post-carrageenan were 53% and 74% for 100 and 300 mg/kg of the AGCa extract and 36% for ARCa (300 mg/kg). Leukocyte recruitment into the peritoneal cavity was inhibited by the extracts. The antioxidant activities of the extracts were higher than the reference antioxidants, ascorbic acid and butylated hydroxytoluene. These results indicate that coffee extracts exhibit anti-inflammatory and antioxidant properties.     

Application of a model using the phenomenological approach for prediction of growth and xanthan gum production with sugar cane broth in a batch process

Production of xanthan gum was studied and modelled using unstructured kinetic models composed of three differential equations, which considered the microbial biomass, carbon source, and xanthan concentration. The fermentation process, using Xanthomonas campestris pv. campestris NRRL B-1459, was conducted under controlled conditions with diluted sugar cane broth at different initial sucrose concentrations (15.0, 25.0, and 35.0 g L⁻¹). Unstructured kinetic models proposed in the literature for this system were reviewed and applied. These models were tested against the experimental results, calculating the parameters by nonlinear regression. The kinetic models used in this study provided estimations of microbial growth, substrate consumption, and product formation, and, therefore, these parameters were quantified in the fermentation experiments. Higher yield of xanthan per amount of sucrose (0.58 g g⁻¹) and productivity (0.63 g L⁻¹ h⁻¹) were obtained using initial sucrose concentrations of 25.0 and 35.0 g L⁻¹, respectively. The models were used to predict the kinetic parameters for a medium containing an intermediate and a larger initial sucrose concentration (27.0 and 40.0 g L⁻¹). When tested experimentally, the measured fermentation parameters were in close agreement with the values predicted by the model that presented the best adjustment, demonstrating its validity.