Multifractality in the random parameter model for multivariate time series

The Random Parameter model was proposed to explain the structure of the covariance matrix in problems where most, but not all, of the eigenvalues of the covariance matrix can be explained by Random Matrix Theory. In this article, we explore the scaling properties of the model, as observed in the multifractal structure of the simulated time series. We use the Wavelet Transform Modulus Maxima technique to obtain the multifractal spectrum dependence with the parameters of the model. The model shows a scaling structure compatible with the stylized facts for a reasonable choice of the parameter values. (C) 2009 Elsevier B.V. All rights reserved.

Incidence of dementia and cause of death in elderly Japanese emigrants to Brazil before World War II

In 1997 we examined the prevalence of dementia among the Japanese elderly immigrants living in the Sao Paulo metropolitan area (n = 166). Herein, we followed up on these subjects for causes of death and dementia incidence. We were able to contact 108 subjects: 54 were already dead. The most common cause of death was cardiac disease. For dementia, 31.6% of the dead subjects were found to have developed dementia before they died, and 20.8% of the living subjects were demented. As for the baseline the clinical dementia rating (CDR), 20.8% of CDR 0 and 50.0% of CDR 0.5 subjects developed dementia in the dead group; whereas in the living group, 23.9% of CDR 0 and 52.6% of CDR 0.5 developed dementia. As a whole, the incidence was 34.2% per 1000 person-years. Cardiac disease as the most common cause of death was probably due to the higher prevalence of diabetes mellitus. Compared with the previous study, the lower incidence of dementia from the CDR 0.5 group may have been due to a higher mortality rate. This is the first study on the incidence of dementia in elderly Japanese immigrants in Brazil. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Incidence of Pressure Ulcers in the Institutionalized Elderly

PURPOSE: The aim of this study was to analyze the incidence of pressure ulcers (PUs) in elderly people living in long-term care facilities (LTCFs). DESIGN: We completed a prospective, comparison cohort study. SUBJECTS AND SETTING: Ninety-four persons, 60 years or older, participated in the study. Participants resided in 4 not-for-profit LTCFs in 3 cities in the southern region of the Brazilian state of Minas Gerais. METHODS: Participants underwent complete skin examination and Braden Scale rating every 2 days for 3 months. When a PU was detected, a careful examination was done to assess its stage, location, and size. From this moment on, the patient was included in the incidence rate and was excluded from the study. RESULTS: The incidence rate of PUs was 39.4%; 37 (77.1%) developed a single ulcer. The most common locations were the malleolus (27.1%) and the ischium (25.0%). Stage I PU were most frequent (66.7%). Females (62.8%) and whites (68.19%) prevailed, with an average age of 79.06 +/- 9.6 years. Body mass index was 20.93 +/- 4.9, with a predominance of urinary diseases (58.5%) and use of neuroleptics/psychotropics (52.1%); 28.7% had had a previous ulcer. Gender and the occurrence of a previous ulcer were found to predict the development of PU, based on logistic regression analysis (r(2) = 0.311). CONCLUSIONS: The overall incidence of PU was significant, but the incidence of stage II and higher PUs was less than 12% and no elders had stage III or IV ulcers. Factors associated with PU development include female gender, regular use of neuroleptic or psychotropic medications, and a history of pressure ulceration.

Incidence of injuries to the lower limbs joints in kung fu athletes

Background and Study Aim: This study evaluated the influence of competitive practice and training aspects on incidence of injuries to the lower limbs joints in formalized (taolu) and combat (sanshou) kung fu athletes. Material/Methods: One hundred and twenty-seven kung fu athletes (taolu, n=82; sanshou, n=45) were interviewed about kung fu practice (practice time, competition time and competition level), training volume (days of training per week and hours per training session) and injury profiles (incidence and type). Continuous variables were compared by non-parametric Kolmogorov-Smirnov test (disciplines and competition levels as grouping variables). The effects of categorical variables (kung fu practice) on injury profiles were analyzed using the Pearson`s chi-square test. The level of significance was set at p<0.05. Results: Our data exhibited large frequency of injury reports (70.1%) and significantly differences on injury profiles between disciplines and competition levels. Taolu athletes, despite the lower practice/competition time (-51.5 and -41.8%, respectively), presented frequency of injury reports twofold greater, longer daily training volume (23.3%) and higher incidence of lower limbs joints injuries than sanshou athletes (35.4% and 11.8%, respectively). Conclusions: Our results suggest a link between injury profiles (incidence and type) and specific characteristics of kung fu disciplines.

Morphological and mechanical properties of hybrid matrices of polysiloxane-polyvinyl alcohol prepared by sol-gel technique and their potential for immobilizing enzyme

Hybrid matrices of polysiloxane-polyvinyl alcohol (POS-PVA) were prepared by sol-gel technique using different concentrations of the organic component (polyvinyl alcohol, PVA) in the synthesis medium. The goal was to prepare carriers for immobilizing enzyme by taking into consideration properties as hardness, mean pore diameter, specific surface area and pore size distribution. The matrices were activated with sodium metaperiodate to render functional groups for binding the lipase from Candida rugosa, used here as a study model. Results showed that low proportion of PVA gave POS-PVA with low surface area and pore volume, although with higher hardness. The chemical activation decreased the pore volume and increased the pore size with a decrease on the surface area of about 60-75%. The matrices for enzyme immobilization were chosen considering the best combination of high surface area and hardness. Thus, the POS-PVA prepared with 5.56 x 10(-5) M of PVA with a surface area of 123 m(2)/g and hardness of 71 HV (50 gf 30 s) was shown to be suitable to immobilize the lipase, with an immobilization yield of about 40%. (c) 2008 Elsevier B.V. All rights reserved.

Stimuli-responsive magnetic particles for biomedical applications

In recent years, magnetic nanoparticles have been studied due to their potential applications as magnetic carriers in biomedical area. These materials have been increasingly exploited as efficient delivery vectors, leading to opportunities of use as magnetic resonance imaging (MRI) agents, mediators of hyperthermia cancer treatment and in targeted therapies. Much attention has been also focused on ""smart"" polymers, which are able to respond to environmental changes, such as changes in the temperature and pH. In this context, this article reviews the state-of-the art in stimuli-responsive magnetic systems for biomedical applications. The paper describes different types of stimuli-sensitive systems, mainly temperature- and pH sensitive polymers, the combination of this characteristic with magnetic properties and, finally, it gives an account of their preparation methods. The article also discusses the main in vivo biomedical applications of such materials. A survey of the recent literature on various stimuli-responsive magnetic gels in biomedical applications is also included. (C) 2010 Elsevier B.V. All rights reserved.

Evaluation of the catalytic properties of Burkholderia cepacia lipase immobilized on non-commercial matrices to be used in biodiesel synthesis from different feedstocks

The objective of this work was to produce an immobilized form of lipase from Burkholderia cepacia (lipase PS) with advantageous catalytic properties and stability to be used in the ethanolysis of different feedstocks, mainly babassu oil and tallow beef. For this purpose lipase PS was immobilized on two different non-commercial matrices, such as inorganic matrix (niobium oxide, Nb(2)O(5)) and a hybrid matrix (polysiloxane-polyvinyl alcohol, SiO(2)-PVA) by covalent binding. The properties of free and immobilized enzymes were searched and compared. The best performance regarding all the analyzed parameters (biochemical properties, kinetic constants and thermal stability) were obtained when the lipase was immobilized on SiO(2)-PVA. The superiority of this immobilized system was also confirmed in the transe-sterification of both feedstocks, attained higher yields and productivities. (C) 2010 Elsevier Ltd. All rights reserved.

A novel electrocatalyst support with proton conductive properties for polymer electrolyte membrane fuel cell applications

The objective of this study is to graft the Surface of carbon black, by chemically introducing polymeric chains (Nafion (R) like) with proton-conducting properties. This procedure aims for a better interaction of the proton-conducting phase with the metallic catalyst particles, as well as hinders posterior support particle agglomeration. Also loss of active surface call be prevented. The proton conduction between the active electrocatalyst site and the Nafion (R) ionomer membrane should be enhanced, thus diminishing the ohmic drop ill the polymer electrolyte membrane fuel cell (PEMFC). PtRu nanoparticles were supported on different carbon materials by the impregnation method and direct reduction with ethylene glycol and characterized using amongst others FTIR, XRD and TEM. The screen printing technique was used to produce membrane electrode assemblies (MEA) for single cell tests in H(2)/air(PEMFC) and methanol operation (DMFC). In the PEMFC experiments, PtRu supported on grafted carbon shows 550 mW cm(-2) gmetal(-1) power density, which represents at least 78% improvement in performance, compared to the power density of commercial PtRu/C ETEK. The DMFC results of the grafted electrocatalyst achieve around 100% improvement. The polarization Curves results clearly show that the main Cause of the observed effect is the reduction in ohmic drop, caused by the grafted polymer. (C) 2009 Elsevier B.V. All rights reserved.

Comparative analysis of triple band S-C-L erbium-doped fibre and semiconductor optical amplifier for CWDM applications

The authors present a comparative analysis between a triple-band S-C-L erbium-doped fibre amplifier and a commercial semiconductor optical amplifier in a CWDM application scenario. Both technologies were characterised for gain and noise figures from 1480 to 1610 nm (S, C and L bands) and their systemic performances were evaluated in terms of bit error rate measurements for a wide range of optical power levels.

Evaluation of austenitic-ferritic stainless steel wires for orthodontic applications

Several studies have shown that austenitic stainless steels are suitable for use in the final phases of orthodontic treatments, such as finishing and retention. These steels demonstrate appropriate mechanical properties, such as high ultimate tensile strength and good corrosion resistance. A new class of materials, the austenic-ferritic stainless steels, is substituting for austenitic stainless steels in several industrial applications where these properties are necessary. This work supports the hypothesis that orthodontic wires of austenic-ferritic stainless steels can replace austenitic stainless steels. The advantages are cost reduction and decrease of the nickel hypersensitivity effect in patients undergoing orthodontic treatments. The object of this study was to evaluate wires of austenitic-ferritic stainless steel SEW 410 Nr. 14517 (Cr26Ni6Mo3Cu3) produced by cold working through rolling and drawing processes. Tests were performed to evaluate the ultimate tensile strength, hardness, ductility, and formability. In accordance with technical standards the wires exhibited ultimate tensile strength and ductility suitable for orthodontic clinical applications. These austenitie-ferritic wires can be an alternative to substitute the common commercial wires of austenic stainless steels with the advantage of decreasing the nickel content.

Composite materials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasse

The aim of this study was to evaluate the potential of the fibrous material obtained from ethanol-water fractionation of bagasse as reinforcement of thermoplastic starches in order to improve their mechanical properties. The composites were elaborated using matrices of corn and cassava starches plasticized with 30 wt%glycerin. The mixtures (0,5,10 and 15 wt% bagasse fiber) were elaborated in a rheometer at 150 degrees C. The mixtures obtained were pressed on a hot plate press at 155 degrees C. The test specimens were obtained according to ASTM D638. Tensile tests, moisture absorption tests for 24 days (20-23 degrees C and 53% RH, ASTM E104), and dynamic-mechanical analyses (DMA) in tensile mode were carried out. Images by scanning electron microscopy (SEM) and X-ray diffraction were obtained. Fibers (10 wt% bagasse fiber) increased tensile strength by 44% and 47% compared to corn and cassava starches, respectively. The reinforcement (15 wt% bagasse fiber) increased more than fourfold the elastic modulus on starch matrices. The storage modulus at 30 C (E(30 degrees C)`) increased as the bagasse fiber content increased, following the trend of tensile elastic modulus. The results indicate that these fibers have potential applications in the development of biodegradable composite materials. (c) 2011 Elsevier B.V. All rights reserved.

Porous alumina-spinel ceramics for high temperature applications

In order to reduce energy costs, high-temperature insulation porous refractory ceramics have been subjected to increasing demands. Among the techniques used to produce these materials (such as the addition of foaming agents and organic compounds), the pore generation via phase transformation presents key aspects, such as easy processing and the absence of toxic volatiles. In this study, this technique was applied to produce porous ceramics by decomposing an aluminum magnesium hydro-carbonate known as hydrotalcite (Mg(6)Al(2)(CO(3))(OH)(16)center dot 4H(2)O). It was found out that by using this complex compound, a large fraction of pores can be generated and kept at high temperatures (above 1300 degrees C) due to the in situ formation of spinel-like phases (MgAl(2)O(4)). (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Monitoring Services for Industrial Applications

Sao Paulo Research Foundation (FAPESP) in Brazil

Comparison between DC(+) and Square Wave AC SAW Current Outputs to Weld AISI 304 for Low-Temperature Applications

Welded equipment for cryogenic applications is utilized in chemical, petrochemical, and metallurgical industries. One material suitable for cryogenic application is austenitic stainless steel, which usually doesn`t present ductile/brittle transition temperature, except in the weld metal, where the presence of ferrite and micro inclusions can promote a brittle failure, either by ferrite cleavage or dimple nucleation and growth, respectively. A 25-mm- (1-in.-) thick AISI 304 stainless steel base metal was welded with the SAW process using a 308L solid wire and two kinds of fluxes and constant voltage power sources with two types of electrical outputs: direct current electrode positive and balanced square wave alternating current. The welded joints were analyzed by chemical composition, microstructure characterization, room temperature mechanical properties, and CVN impact test at -100 degrees C (-73 degrees F). Results showed that an increase of chromium and nickel content was observed in all weld beads compared to base metal. The chromium and nickel equivalents ratio for the weld beads were always higher for welding with square wave AC for the two types of fluxes than for direct current. The modification in the Cr(eq)/Ni(eq) ratio changes the delta ferrite morphology and, consequently, modifies the weld bead toughness at lower temperatures. The oxygen content can also affect the toughness in the weld bead. The highest absorbed energy in a CVN impact test was obtained for the welding condition with square wave AC electrical output and neutral flux, followed by DC(+) electrical output and neutral flux, and square wave AC electrical output and alloyed flux.

Electro-optically sensitive diamond-like carbon thin films deposited by reactive magnetron sputtering for electronic device applications

The goal of this work is to study and relate electrical and optical properties of diamond-like carbon (DLC) thin films for applications in electronic devices. DLC films were deposited in a reactive RF magnetron sputtering system on p-type silicon and glass substrates. The target was a 99.9999% pure, 6 in. diameter graphite plate and methane was used as processing gas. Eight DLC films were produced for each substrate, varying deposition time, the reactor pressure between 5 mTorr and 10 mTorr while the RF power was applied at 13.56 MHz and varied between 100, 150, 200 and 250W. After deposition, the films were analyzed by I-V and C-V measurements (Cheng et al. (2004) [1]) in order to determine the electric resistivity, photo-current response and dielectric constant, optical transmittance, used to find the optical gap by the Tauc method; and by photoluminescence analysis to determine the photoemission and confirm the optical band gap. These characteristics are compared and the influence of the deposition parameters is discussed. (C) 2011 Published by Elsevier B.V.