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711.
    
Abstract

This study reports on the development and validation of a new computer model for simulating human postures at work, and assessing the reaction forces and bending moments in 43 human articulation joints. The proposed model estimates the intradiscal pressure in the vertebral column in response to external loading forces encountered during human interactions with work objects or processes. The model was implemented in a self-contained interactive software package. The simulation results compare favorably with the reported experimental data, and provide reasonable confidence in the quality of the model. Its characteristics and its applications in evaluating physical task performance are also discussed  相似文献   
712.
    
There is great interest in developing eco-friendly green biocomposites from plant-derived natural fibers and crop-derived bioplastics attributable to their renewable resource-based origin and biodegradable nature. Fully biodegradable composites, made from both biodegradable polymeric matrices and natural fibers, should be advantageous in some applications, such as one way packaging. Polyhydroxyalkanoates (PHAs) are naturally occurring biodegradable polymers produced from a wide range of microorganisms, with poly(3-hydroxybutyrate) P(3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) being important examples of PHAs. In this work, biocomposites of PHBV consisting of a PHBV matrix incorporating peach palm particles (PPp), [i.e., 100/0, 90/10, 80/20 and 75/25 (%w/w) PHBV/PPp] were processed by injection molding at 160 °C. The effect of PPp loading on the thermal and the mechanical properties, as well as on the morphological behavior of the PHBV/PPp biocomposites was investigated. Soil biodegradation tests were carried out by burying specimen beakers containing aged soil and kept under controlled temperature and humidity in accordance with ASTM G160-98. Degradation of the biocomposites was evaluated by visual analysis, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) following test exposures of up to 5 months. The addition of PPp reduced the maximum strength and the elongation at break of the biocomposites. On the other hand, the Young’s modulus improved with the PPp content. Micrographs of the fracture surfaces following tensile strength testing revealed a large distance between the PHBV matrix and PPp particles although a low interaction is expected. Where measured, these distances tended increase as the PPp content of the biocomposites increased. Soil biodegradation tests indicated that the biocomposites degraded faster than the neat polymer due to the presence of cavities that resulted from introduction of the PPp and that degradation increased with increasing PPp content. These voids allowed for enhanced water adsorption and greater internal access to the soil-borne degrader microorganisms.  相似文献   
713.
In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.  相似文献   
714.
    
Journal of Material Cycles and Waste Management - A crushed concrete aggregate, processed from construction and demolition waste and a siderurgical aggregate, processed from electric arc furnace...  相似文献   
715.
The aim of this study is to test a model on the relationships between organizational and group safety climate and safety performance, that highlights the importance of co-workers as a safety climate agent side by side supervisors at group level. The idea is to consider the co-workers’ safety climate as a necessary part of a multilevel model of safety climates’ framework associated to safety performance. Firstly, the assessment of the safety climates’ framework which consider organizational safety climate and at group level supervisor’s and co-workers’ safety climate was performed. Then, the mediating role of co-workers’ safety climate between organizational and supervisor’s safety climate, and worker’s safety behaviours was explored. From the literature, the importance to study safety climate in a multilevel perspective by a theoretical and methodological point of view is known. For these reasons the proposed models were tested with multilevel structural equation modelling. We used a two-level design which considered the individual level and the work-group level. Data collection involved 991 blue-collars, belonging to 91 work groups, from five Italian manufacturing companies. The research highlighted the importance of considering at group level not only climate referred to supervisor, but also climate referred to co-workers. Furthermore, results confirmed the mediating role of co-workers’ safety climate and revealed that co-workers’ safety climate had a stronger influence on safety behaviours, and in particular on safety participation, than supervisor’s safety climate, at individual level as well at group level.  相似文献   
716.
Ketoprofen is an analgesic with potent anti-inflammatory activity against acute inflammation, subacute inflammation, for the acute and long-term treatment of various inflammatory pathologies, as rheumatoid arthritis and colonic adenocarcinoma. In order to minimize the incidence of systemic events related to ketoprofen, the transdermal drug delivery system development has been most important. The advantages of using natural rubber latex membranes include not only the reduction of adverse systemic events, but also the suitability of the low cost of the material together with its physicochemical properties such as flexibility, mechanical stability, surface porosity and water vapor permeability, and besides being a biocompatible material also presents biological activity to stimulate the angiogenesis, being able to be used in tissue repair. This study demonstrated that ketoprofen was successfully incorporated into natural latex membranes for drug delivery. FTIR indicated that the drug did not interact chemically with the membrane. Moreover, the natural latex membranes released 60% of the ketoprofen incorporated in 50 h. SEM images indicated that a portion of the drug was present on the membrane surface, being this portion responsible for the burst release. The tensile tests showed that the addition of the drug into the natural latex membrane did not influence on the polymer mechanical behavior. In addition, drug-natural latex membranes presented no red blood cell damaging effects. Our data shows that the ketoprofen loaded natural latex membranes is a promising system for sustained drug delivery which can be used to minimize the adverse side effects of high dose systemic drug delivery.  相似文献   
717.
Data from the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) indicate significant changes have occurred in precipitation chemistry and the chemical climate in the United States (US). A Seasonal Kendall Trend (SKT) analysis shows statistically significant increases in precipitation ammonium concentrations at 64% of 159 continental US NADP/NTN sites evaluated from Winter 1985 to Fall 2004 (Dec. 1984 – Nov. 2004). Sulfate decreases were widespread, with an SKT analysis indicating statistically significant decreases at 89% of sites evaluated. Ratios of chemical equivalent concentrations of ammonium to sulfate in precipitation have risen to the extent that ammonium now exceeds sulfate over more than half of the continental U.S. on a precipitation-weighted-mean annual basis. These trends in the concentrations of ammonium, sulfate, and other species have been accompanied by significant decreases in the frequency of acidic precipitation (pH < 5.0) in the last decade.  相似文献   
718.
    
To-date, only two UIC Class VI permits have been issued by the US Environmental Protection Agency. We illustrate a four-phase workflow to first identify regional storage resources and then down-select sites to yield permit-ready locations that can accept and store large volumes of CO2. Specific permit requirements should guide objectives and define deliverables of respective workflow phases. In the first phase we used available regional data and screened structure and injection zones to locate resources that match CO2 volumes planned to be captured. Available data were also used to assess presence and depth of usable groundwater, the key resource being protected via permitting. We then used advanced, closed-form, analytical solutions (EASiTool) to estimate CO2 injectivity into each hydrologically connected injection compartment. In the second phase we acquired and conditioned additional wireline logs and leased available seismic datasets. We interpreted the depositional systems from wireline well-log character and mapped sandbody geometry to interpolate injection and confining-zone distribution. Using available data, we mapped faults and locations of freshwater and overpressure (or other capacity-limiting geologic parameters) in more detail. In the third phase, we used the augmented geologic data to develop a static model for the selected area, extracted the areas of highest interest, and generated and ran dynamic (flow) models. In a fourth phase, we reduced major uncertainties identified in earlier phases. Our case study indicates that to complete preparation of a permit application requires (1) improved lithologic characterization information (thicknesses and horizontal and vertical connectivity) and (2) better definition of poorly defined local faults. © 2023 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.  相似文献   
719.
720.
Medical wastes management in the south of Brazil   总被引:2,自引:0,他引:2  
In developing countries, solid wastes have not received sufficient attention. In many countries, hazardous and medical wastes are still handled and disposed together with domestic wastes, thus creating a great health risk to municipal workers, the public and the environment. Medical waste management has been evaluated at the Vacacai river basin in the State of Rio Grande do Sul, Brazil. A total of 91 healthcare facilities, including hospitals (21), health centers (48) and clinical laboratories (22) were surveyed to provide information about the management, segregation, generation, storage and disposal of medical wastes. The results about management aspects indicate that practices in most healthcare facilities do not comply with the principles stated in Brazilian legislation. All facilities demonstrated a priority on segregation of infectious-biological wastes. Average generation rates of total and infectious-biological wastes in the hospitals were estimated to be 3.245 and 0.570 kg/bed-day, respectively.  相似文献   
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