Simultaneous effect of shift work on blood pressure and lipid profile: a path analysis

The aim of this study was to assess the direct and indirect effects of shift work (SW) on the systolic blood pressure (SBP) and lipid profile of male workers. For this purpose, a cross-sectional study was conducted involving 6539 male workers of Esfahan Mobarakeh Steel Company. From all of the participants, 3065 (46.8%) were day workers and the remainder were shift workers. The results of path analysis revealed that the most effective variables on SBP were body mass index, fasting blood sugar, triglycerides and SW with a total effect of 0.241, 0.095, 0.064 and 0.056, respectively.     

A sustainable method for optimizing product design with trade-off between life cycle cost and environmental impact

In today’s competitive market, corporations have learned that taking sustainability issues into account can significantly improve their public image. Modern producers therefore must simultaneously reduce the environmental impact of their products and make economic gains. Therefore, making trade-offs between economic and environmental issues is required to ensure a company’s continuity. In doing so, companies have attached a great deal of importance to the new product design phase. However, optimization at the design stage becomes very complex for a product with a large number of parts, which can have several design alternatives with similar forms and functionality, but different costs and environmental impacts. In the automobile, shipbuilding and aircraft industries, if the conventional complete enumeration method is applied, the time required for selecting the optimal combination of design alternatives with respect to life cycle cost and environmental impact may exceed a human’s natural life span. To overcome this limitation, this paper introduces an optimization method for use as a design aid tool that enables a designer to assess the life cycle cost and environmental impact of his/her design very early in the product development process. To support the developed method, an illustration is provided using a case study on a locally manufactured automobile.     

Physiological characteristics of <Emphasis Type="Italic">Plantago major</Emphasis> under SO<Subscript>2</Subscript> exposure as affected by foliar iron spray

Sulfur dioxide (SO₂) is considered as a main air pollutant in industrialized areas that can damage vegetation. In the present study, we investigated how exposure to SO₂ and foliar application of iron (Fe) would affect certain physiological characteristics of Plantago major. The plant seedlings exposed or unexposed to SO₂ (3900 μg m^?3) were non-supplemented or supplemented with Fe (3 g L^?1) as foliar spray. Plants were exposed to SO₂ for 6 weeks in 100 × 70 × 70 cm chambers. Fumigation of plants with SO₂ was performed for 3 h daily for 3 days per week (alternate day). Lower leaf Fe concentration in the plants exposed to SO₂ at no added Fe treatment was accompanied with incidence of chlorosis symptoms and reduced chlorophyll concentration. No visible chlorotic symptoms were observed on the SO₂-exposed plants supplied with Fe that accumulated higher Fe in their leaves. Both at with and without added Fe treatments, catalase (CAT) and peroxidase (POD) activity was higher in the plants fumigated with SO₂ in comparison with those non-fumigated with SO₂. Foliar application of Fe was also effective in increasing activity of antioxidant enzymes CAT and POD. Exposure to SO₂ led to reduced cellulose but enhanced lignin content of plant leaf cell wall. The results obtained showed that foliar application of Fe was effective in reducing the effects of exposure to SO₂ on cell wall composition. In contrast to SO₂, application of Fe increased cellulose while decreased lignin content of the leaf cell wall. This might be due to reduced oxidative stress induced by SO₂ in plants supplied with Fe compared with those unsupplied with Fe.     

Reducing As availability in calcareous soils using nanoscale zero valent iron

Environmental Science and Pollution Research - Different methods, including the use of nanoscale zero-valent iron (NZVI), have been used to treat arsenic (As)-contaminated environments, with much...     

Starting improvement of micro-wind turbines operating in low wind speed regions

The study deals with the design and optimization of external and internal geometry of micro-wind turbines blades. A specified objective function which consists of the power coefficient and the starting time was defined and the genetic algorithm optimization technique in conjunction with the blade-element momentum theory was adopted to find the geometry of the blades including the distributions of the chord, the twist angle and also the shell thickness. Moreover, the allowable stress of the blades was considered as a constraint to the objective function. Results show that a reasonable compromise is achievable such that the starting time of the blades reduces noticeably in return for a small drop in the power coefficient. The significant improvement of the hollow blades over the solid ones indicates that the power coefficient and the starting performance could be improved through the appropriate distributions of the considered decision variables, i.e. the chord, the twist angle and also the shell thickness.     

Adsorption of Crystal Violet Dye from Aqueous Solution by Poly(Acrylamide-<Emphasis Type="Italic">co</Emphasis>-Maleic Acid)/Montmorillonite Nanocomposite

Poly(acrylamide-co-maleic acid)/montmorillonite nanocomposites, were synthesized via in situ polymerization with different maleic acid and MMT content. The capability of the hydrogel for adsorption of crystal violet (CV) was investigated in aqueous solutions at different pH values and temperatures. The pseudo-second-order kinetics model could fit successfully the adsorption kinetic data. The effects of maleic acid to acrylamide molar ratio (MA_R), weight percent of MMT (MMT%), the pH of medium and the solution temperature (T) on the CV adsorption capacity (q _e ) of adsorbents were studied by Taguchi experimental design approach. The results indicated that increasing the MMT% leads to a greater q _e . The q _e value of adsorbents increased also with increasing both MA_R and pH, while reduced when the temperature of medium increased. The relatively optimum conditions to achieve a maximum CV adsorption capacity for P(AAm/MA)/MMT adsorbents were found as: 0.06 for MA_R and 5 % of MMT%, medium pH = 7 and T = 20 °C.     

Analysis of gross alpha, gross beta activities and beryllium-7 concentrations in surface air: their variations and statistical prediction model

Measurement of gross α, gross β activities and cosmogenic beryllium-7 (⁷Be) concentrations were made both daily and weekly during the years 2001–2004 from samples of atmospheric aerosols filtered from the air at Tehran Nuclear Research Center (35 41′ N) and Zahedan (28 29′ N). Weekly aerosol samples collected with the high-volume air samplers on cellulose filters were used to determine the ⁷Be contents of samples, using a semiconductor gamma spectrometer. Airborne dust samples were collected daily on fiber glass filters and used to determine the gross β and gross α activities with automatic beta analyzer and a ZnS(Ag) counter, respectively. In this work, the concentration and meteorological data were used to determine models for gross α, gross β and ⁷Be. The air concentrations of gross β and gross α activities and ⁷Be concentrations displayed lognormal distributions during the study period. Both β and ⁷Be have maximum activity concentrations during warm mid-year months.     

Use of plastic waste (poly-ethylene terephthalate) in asphalt concrete mixture as aggregate replacement.

One of the environmental issues in most regions of Iran is the large number of bottles made from poly-ethylene terephthalate (PET) deposited in domestic wastes and landfills. Due to the high volume of these bottles, more than 1 million m3 landfill space is needed for disposal every year. The purpose of this experimental study was to investigate the possibility of using PET waste in asphalt concrete mixes as aggregate replacement (Plastiphalt) to reduce the environmental effects of PET disposal. For this purpose the mechanical properties of plastiphalt mixes were compared with control samples. This study focused on the parameters of Marshall stability, flow, Marshall quotient (stability-to-flow ratio) and density. The waste PET used in this study was in the form of granules of about 3 mm diameter which would replace (by volume) a portion of the mineral coarse aggregates of an equal size (2.36-4.75 mm). In all prepared mixes the determined 6.6% optimum bitumen content was used. In this investigation, five different percentages of coarse aggregate replacement were used. The results showed that the aggregate replacement of 20% by volume with PET granules would result in a reduction of 2.8% in bulk compacted mix density. The value of flow in the plastiphalt mix was lower than that of the control samples. The results also showed that when PET was used as partial aggregate replacement, the corresponding Marshall stability and Marshall quotient were almost the same as for the control samples. According to most of specification requirement, these results introduce an asphalt mix that has properties that makes it suitable for practical use and furthermore, the recycling of PET for asphalt concrete roads helps alleviate an environmental problem and saves energy.     

Self body-size perception in an insect

Animals negotiating complex environments encounter a wide range of obstacles of different shapes and sizes. It is greatly beneficial for the animal to react to such obstacles in a precise, context-specific manner, in order to avoid harm or even simply to minimize energy expenditure. An essential key challenge is, therefore, an estimation of the animal’s own physical characteristics, such as body size. A further important aspect of self body-size perception (or SBSP) is the need to update it in accordance with changes in the animal’s size and proportions. Despite the major role of SBSP in functional behavior, little is known about if and how it is mediated. Here, we demonstrate that insects are also capable of self perception of body size and that this is a vital factor in allowing them to adjust their behavior following the sudden and dramatic growth associated with periodic molting. We reveal that locusts’ SBSP is strongly correlated with their body size. However, we show that the dramatic change in size accompanying adult emergence is not sufficient to create a new and updated SBSP. Rather, this is created and then consolidated only following the individuals’ experience and interaction with the physical environment. Behavioral or pharmacological manipulations can both result in maintenance of the old larval SBSP. Our results emphasize the importance of learning and memory-related processes in the development and update of SBSP, and highlight the advantage of insects as good models for a detailed study on the neurobiological and molecular aspects of SBSP.