Evaluation of biologic occupational risk control practices: Quality indicators development and validation

Background: There is growing demand for the adoption of qualification systems for health care practices. This study is aimed at describing the development and validation of indicators for evaluation of biologic occupational risk control programs. Methods: The study involved 3 stages: (1) setting up a research team, (2) development of indicators, and (3) validation of the indicators by a team of specialists recruited to validate each attribute of the developed indicators. The content validation method was used for the validation, and a psychometric scale was developed for the specialists` assessment. A consensus technique was used, and every attribute that obtained a Content Validity Index of at least 0.75 was approved. Results: Eight indicators were developed for the evaluation of the biologic occupational risk prevention program, with emphasis on accidents caused by sharp instruments and occupational tuberculosis prevention. The indicators included evaluation of the structure, process, and results at the prevention and biologic risk control levels. The majority of indicators achieved a favorable consensus regarding all validated attributes. Conclusion: The developed indicators were considered validated, and the method used for construction and validation proved to be effective.

Control of interceptive actions is based on expectancy of time to target arrival

In this study the hypothesis that interceptive movements are controlled on the basis of expectancy of time to target arrival was tested. The study was conducted through assessment of temporal errors and kinematics of interceptive movements to a moving virtual target. Initial target velocity was kept unchanged in part of the trials, and in the others it was decreased 300 ms before the due time of target arrival at the interception position, increasing in 100 ms time to target arrival. Different probabilities of velocity decrease ranging from 25 to 100% were compared. The results revealed that while there were increasing errors between probabilities of 25 and 75% for unchanged target velocity, the opposite relationship was observed for target velocity decrease. Kinematic analysis indicated that movement timing adjustments to target velocity decrease were made online. These results support the conception that visuomotor integration in the interception of moving targets is mediated by an internal forward model whose weights can be flexibly adjusted according to expectancy of time to target arrival.

Postural control during prolonged standing in persons with chronic low back pain

Prolonged standing has been associated with the onset of low back pain symptoms in working populations. So far, it is unknown how individuals with chronic low back pain (CLBP) behave during prolonged unconstrained standing (PS). The aim of the present study was to analyze the control of posture by subjects with CLBP during PS in comparison to matched healthy adults. The center of pressure (COP) position of 12 CLBP subjects and 12 matched healthy controls was recorded in prolonged standing (30 min) and quiet stance tasks (60 s) on a force plate. The number and amplitude of COP patterns, the root mean square (RMS), speed, and frequency of COP sway were analyzed. Statistical analyses showed that CLBP subjects produced less Postural changes in the antero-posterior direction with decreased postural sway during the prolonged standing task in comparison to the healthy group. Only CLBP subjects were influenced by the prolonged standing task, as demonstrated by their increased COP RMS, COP speed and COP frequency in the quiet standing trial after the prolonged standing task in comparison to the pre-PS trial. The present study provides additional evidence that individuals with CLBP might have altered sensory-motor function. Their inability to generate responses similar to those of healthy subjects during prolonged standing may contribute to CLBP persistence or an increase risk of recurrent back pain episodes. Moreover, quantification of postural changes during prolonged standing could be useful to identify CLBP subjects prone to postural control deficits. (C) 2008 Elsevier B.V. All rights reserved.

Complexity of human postural control in young and older adults during prolonged standing

Aging is known to have a degrading influence on many structures and functions of the human sensorimotor system. The present work assessed aging-related changes in postural sway using fractal and complexity measures of the center of pressure (COP) dynamics with the hypothesis that complexity and fractality decreases in the older individuals. Older subjects (68 +/- 4 years) and young adult subjects (28 +/- 7 years) performed a quiet stance task (60 s) and a prolonged standing task (30 min) where subjects were allowed to move freely. Long-range correlations (fractality) of the data were estimated by the detrended fluctuation analysis (DFA); changes in entropy were estimated by the multi-scale entropy (MSE) measure. The DFA results showed that the fractal dimension was lower for the older subjects in comparison to the young adults but the fractal dimensions of both groups were not different from a 1/f noise, for time intervals between 10 and 600 s. The MSE analysis performed with the typically applied adjustment to the criterion distance showed a higher degree of complexity in the older subjects, which is inconsistent with the hypothesis that complexity in the human physiological system decreases with aging. The same MSE analysis performed without adjustment showed no differences between the groups. Taken all results together, the decrease in total postural sway and long-range correlations in older individuals are signs of an adaptation process reflecting the diminishing ability to generate adequate responses on a longer time scale.

Effect of bandwidth knowledge of results on the learning of a grip force control task

An experiment was conducted to investigate the persistence of the effect of ""bandwidth knowledge of results (KR)"" manipulated during the learning phase of performing a manual force-control task. The experiment consisted of two phases, an acquisition phase with the goal of maintaining 60% maximum force in 30 trials, and a second phase with the objective of maintaining 40% of maximum force in 20 further trials. There were four bandwidths of KR: when performance error exceeded 5, 10, or 15% of the target, and a control group (0% bandwidth). Analysis showed that 5, 10, and 15% bandwidth led to better performance than 0% bandwidth KR at the beginning of the second phase and persisted during the extended trials.

Effect of hemicellulose and lignin on enzymatic hydrolysis of cellulose from brewer`s spent grain

Enzymatic hydrolysis of brewer`s spent grain in three different forms: original (untreated), pretreated by dilute acid (cellulignin), and pretreated by a sequence of dilute acid and dilute alkali (cellulose pulp), was studied to verify the effect of hemicellulose and lignin on cellulose conversion into glucose. The hydrolysis was carried out using a commercial cellulase concentrate (Celluclast 1.5 L) in an enzyme/substrate ratio of 45 FPU/g, 2% (w/v) substrate concentration, 45 degrees C for 96 h. According to the results, the cellulose hydrolysis was affected by the presence of hemicellulose and/or lignin in the sample. The cellulose conversion ratio (defined as glucose yield + cellobiose yield) from cellulignin was 3.5-times higher than that from untreated sample, whereas from cellulose pulp such value was 4-times higher, correspondent to 91.8% (glucose yield of 85.6%). This best result was probably due to the strong modification in the material structure caused by the hemicellulose and lignin removal from the sample. As a consequence, the cellulose fibers were separated being more susceptible to the enzymatic attack. It was concluded that the lower the hemicellulose and lignin contents in the sample, the higher the efficiency of cellulose hydrolysis. (C) 2007 Elsevier Inc. All rights reserved.

Effects of medium supplementation and pH control on lactic acid production from brewer`s spent grain

A cellulose pulp obtained by chemical pre-treatment of brewer`s spent grain was saccharified by a commercial cellulase preparation and the produced hydrolysate (50 g/l glucose) was fermented to lactic acid by Lactobacillus delbrueckii. The effects of pH control and nutrient supplementation of the hydrolysate on fermentation performance were investigated. Addition of 5g/l yeast extract enhanced the lactic acid volumetric productivity that attained 0.53 g/l h, value 18% higher than that obtained from non-supplemented hydrolysate. Addition of the MRS broth medium components (except the carbon source) was still better, providing a productivity of 0.79 g/l h. In all the cases, the lactic acid yield factor was of 0.7 g/g glucose consumed, but the fermentations stopped after 24 h due to the pH drop from 6.0 to 4.2, resulting in large amounts of residual glucose (38-41 g/l). Fermentation runs pH-controlled at 6.0 gave better results than those where the initial pH was not further controlled. The best result, 35.54 g/l lactic acid (0.99 g/g glucose consumed) was obtained during the pH-controlled fermentation of hydrolysate medium supplemented with MRS components. The volumetric productivity at the end of this fermentation was 0.59 g/l h, with a maximum of 0.82 g/l h during the first 12 h. (c) 2008 Elsevier B.V. All rights reserved.

Lignocellulosic polysaccharides and lignin degradation by wood decay fungi: the relevance of nonenzymatic Fenton-based reactions

The brown rot fungus Wolfiporia cocos and the selective white rot fungus Perenniporia medulla-panis produce peptides and phenolate-derivative compounds as low molecular weight Fe(3+)-reductants. Phenolates were the major compounds with Fe(3+)-reducing activity in both fungi and displayed Fe(3+)-reducing activity at pH 2.0 and 4.5 in the absence and presence of oxalic acid. The chemical structures of these compounds were identified. Together with Fe(3+) and H(2)O(2) (mediated Fenton reaction) they produced oxygen radicals that oxidized lignocellulosic polysaccharides and lignin extensively in vitro under conditions similar to those found in vivo. These results indicate that, in addition to the extensively studied Gloeophyllum trabeum-a model brown rot fungus-other brown rot fungi as well as selective white rot fungi, possess the means to promote Fenton chemistry to degrade cellulose and hemicellulose, and to modify lignin. Moreover, new information is provided, particularly regarding how lignin is attacked, and either repolymerized or solubilized depending on the type of fungal attack, and suggests a new pathway for selective white rot degradation of wood. The importance of Fenton reactions mediated by phenolates operating separately or synergistically with carbohydrate-degrading enzymes in brown rot fungi, and lignin-modifying enzymes in white rot fungi is discussed. This research improves our understanding of natural processes in carbon cycling in the environment, which may enable the exploration of novel methods for bioconversion of lignocellulose in the production of biofuels or polymers, in addition to the development of new and better ways to protect wood from degradation by microorganisms.

Enzymatic Hydrolysis of Chemithermomechanically Pretreated Sugarcane Bagasse and Samples with Reduced Initial Lignin Content

Chemithermomechanical (CTM) processing was used to pretreat sugarcane bagasse with the aim of increasing cell wall accessibility to hydrolytic enzymes. Yields of the pretreated samples were in the range of 75-94%. Disk refining and alkaline-CTM and alkaline/sulfite-CTM pretreatments yielded pretreated materials with 21.7, 17.8, and 15.3% of lignin, respectively. Hemicellulose content was also decreased to some extent. Fibers of the pretreated materials presented some external fibrillation, fiber curling, increased swelling, and high water retention capacity. Cellulose conversion of the alkaline-CTM- and alkaline/sulfite-CTM-pretreated samples reached 50 and 85%, respectively, after 96 h of enzymatic hydrolysis. Two samples with low initial lignin content were also evaluated after the mildest alkaline-CTM pretreatment. One sample was a partially delignified mill-processed bagasse. The other was a sugarcane hybrid selected in a breeding program. Samples with lower initial lignin content were hydrolyzed considerably faster in the first 24 h of enzymatic digestion. For example, enzymatic hydrolysis of the sample with the lowest initial lignin content (14.2%) reached 64% cellulose conversion after only 24 h of hydrolysis when compared with the 30% observed for the mill-processed bagasse containing an initial lignin content of 24.4%. (C) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 27: 395-401, 2011

The roles of xylan and lignin in oxalic acid pretreated corncob during separate enzymatic hydrolysis and ethanol fermentation

High yields of hemicellulosic and cellulosic sugars are critical in obtaining economical conversion of agricultural residues to ethanol. To optimize pretreatment conditions, we evaluated oxalic acid loading rates, treatment temperatures and times in a 2(3) full factorial design. Response-surface analysis revealed an optimal oxalic acid pretreatment condition to release sugar from the cob of Zea mays L ssp. and for Pichia stipitis CBS 6054. To ferment the residual cellulosic sugars to ethanol following enzymatic hydrolysis, highest saccharification and fermentation yields were obtained following pretreatment at 180 degrees C for 50 min with 0.024 g oxalic acid/g substrate. Under these conditions, only 7.5% hemicellulose remained in the pretreated substrate. The rate of cellulose degradation was significantly less than that of hemicellulose and its hydrolysis was not as extensive. Subsequent enzymatic saccharification of the residual cellulose was strongly affected by the pretreatment condition with cellulose hydrolysis ranging between 26.0% and 76.2%. The residual xylan/lignin ratio ranged from 0.31 to 1.85 depending on the pretreatment condition. Fermentable sugar and ethanol were maximal at the lowest ratio of xylan/lignin and at high glucan contents. The model predicts optimal condition of oxalic acid pretreatment at 168 degrees C, 74 min and 0.027 g/g of oxalic acid. From these findings, we surmised that low residual xylan was critical in obtaining maximal glucose yields from saccharification. Published by Elsevier Ltd.

Production, characterization and application of activated carbon from brewer`s spent grain lignin

Different types of activated carbon were prepared by chemical activation of brewer`s spent grain (BSG) lignin using H(3)PO(4) at various acid/lignin ratios (1, 2, or 3 g/g) and carbonization temperatures (300, 450, or 600 degrees C), according to a 2(2) full-factorial design. The resulting materials were characterized with regard to their surface area, pore volume, and pore size distribution, and used for detoxification of BSG hemicellulosic hydrolysate (a mixture of sugars, phenolic compounds, metallic ions, among other compounds). BSG carbons presented BET surface areas between 33 and 692 m(2)/g, and micro- and mesopores with volumes between 0.058 and 0.453 cm(3)/g. The carbons showed high capacity for adsorption of metallic ions, mainly nickel, iron, chromium, and silicon. The concentration of phenolic compounds and color were also reduced by these sorbents. These results suggest that activated carbons with characteristics similar to those commercially found and high adsorption capacity can be produced from BSG lignin. (C) 2009 Elsevier Ltd. All rights reserved.

Linoleic acid peroxidation and lignin degradation by enzymes produced by Ceriporiopsis subvermispora grown on wood or in submerged liquid cultures

Ceriporiopsis subvermispora is a white-rot fungus used in biopulping processes and seems to use the fatty acid peroxidation reactions initiated by manganese-peroxidase (MnP) to start lignin degradation. The present work shows that C. subvermispora was able to peroxidize unsaturated fatty acids during wood biotreatment under biopulping conditions. In vitro assays showed that the extent of linoleic acid peroxidation was positively correlated with the level of MnP recovered from the biotreated wood chips. Milled wood was treated in vitro by partially purified MnP and linoleic acid. UV spectroscopy and size exclusion chromatography (SEC) showed that soluble compounds similar to lignin were released from the milled wood. SEC data showed a broad elution profile compatible with low molar mass lignin fractions. MnP-treated milled wood was analyzed by thioacidolysis. The yield of thioacidolysis monomers recovered from guaiacyl and syringyl units decreased by 33% and 20% in MnP-treated milled wood, respectively. This has suggested that lignin depolymerization reactions have occurred during the MnP/linoleic acid treatment. (C) 2009 Elsevier Inc. All rights reserved.

City tuberculosis control coordinators` perspectives of patient adherence to DOT in Sao Paulo State, Brazil, 2005

SETTING: Thirty-six priority cities in Sao Paulo State, Brazil, with a high incidence of tuberculosis (TB) cases, deaths and treatment default. OBJECTIVE: To identify the perspectives of city TB control coordinators regarding the most important components of adherence strategies adopted by health care teams to ensure patient adherence in 36 priority cities in the State of Sao Paulo, Brazil. DESIGN: Qualitative research with semi-structured interviews conducted with the coordinators of the National TB Control Programme involved in the management of TB treatment services in the public sector. RESULTS: The main issues thought to influence adherence to directly observed treatment (DOT) by coordinators include incentives and benefits delivered to patients, patient-health care worker bonding and comprehensive care, the encouragement given by others to follow treatment (family, neighbours and health professionals), and help provided by health professionals for patients to recover their self-esteem. CONCLUSION: The main aspects mentioned by city TB control coordinators regarding patient adherence to treatment and to DOT in Sao Paulo are improvements in communications, relationships based on trust, a humane approach and including the patients in the decision-making process concerning their health.

Embedded DSP-Based Compact Fuzzy System and Its Application for Induction-Motor V/f Speed Control

This paper presents a compact embedded fuzzy system for three-phase induction-motor scalar speed control. The control strategy consists in keeping constant the voltage-frequency ratio of the induction-motor supply source. A fuzzy-control system is built on a digital signal processor, which uses speed error and speed-error variation to change both the fundamental voltage amplitude and frequency of a sinusoidal pulsewidth modulation inverter. An alternative optimized method for embedded fuzzy-system design is also proposed. The controller performance, in relation to reference and load-torque variations, is evaluated by experimental results. A comparative analysis with conventional proportional-integral controller is also achieved.

Robust STATCOM control for the stabilisation of fixed-speed wind turbines during low voltages

This paper presents a robust voltage control scheme for fixed-speed wind generators using a static synchronous compensator (STATCOM) controller. To enable a linear and robust control framework with structured uncertainty, the overall system is represented by a linear part plus a nonlinear part that covers an operating range of interest required to ensure stability during severe low voltages. The proposed methodology is flexible and readily applicable to larger wind farms of different configurations. The performance of the control strategy is demonstrated on a two area test system. Large disturbance simulations demonstrate that the proposed controller enhances voltage stability as well as transient stability of induction generators during low voltage ride through (LVRT) transients and thus enhances the LVRT capability. (C) 2011 Elsevier Ltd. All rights reserved.