Advanced energy‐based analyses of trusses employing hybrid metaheuristics

Total potential optimization using metaheuristic algorithm (TPO/MA) is an alternative method in structural analyses, and it is a black‐box application for nonlinear analyses. In the study, an advanced TPO/MA using hybridization of several metaheuristic algorithms is investigated to solve large‐scale structural analyses problems. The new generation algorithms considered in the study are flower pollination algorithm (FPA), teaching learning‐based optimization, and Jaya algorithm (JA). Also, the proposed methods are compared with methodologies using classic and previously used algorithms such as differential evaluation, particle swarm optimization, and harmony search. Numerical investigations were carried out for structures with four to 150 degrees of freedoms (design variables). It has been seen that in several runs, JA gets trapped into local solutions. For that reason, four different hybrid algorithms using fundamentals of JA and phases of other algorithms, namely, JA using Lévy flights, JA using Lévy flights and linear distribution, JA with consequent student phase, and JA with probabilistic student phase (JA1SP), are developed. It is observed that among the variants tried, JA1SP is seen to be more effective on approaching to the global optimum without getting trapped in a local solution.     

Statin use is associated with lower inflammation and erythropoietin responsiveness index in hemodialysis patients

Patients with end-stage renal disease are prone to inflammation and inflammation is related to erythropoietin-stimulating agent hyporesponsiveness and mortality in this population. Statins have been demonstrated to reduce cardiovascular mortality in selected populations of end-stage renal disease patients. These drugs have pleiotrophic effects such as anti-inflammation. In this retrospective analysis, we determined whether the use of statins improves inflammation and inflammation-related anemia in a cohort of hemodialysis patients. Data were analyzed from Fresenius Medical Care Dialysis Clinics in Turkey between 2005 and 2007. Seventy prevalent hemodialysis patients who were on statins at the start of the study and have been on statins during follow-up (statin users) and 1293 patients who were not on statin at the start of the study and had never been prescribed any lipid-modifying drugs during follow-up (statin nonusers) were included in the study. High-sensitive C-reactive protein levels were significantly decreased in statin users (1.50±1.49 vs. 1.33±1.11 mg/L, P=0.05) compared with nonusers (1.93±3.22 vs. 2.05±2.77 mg/L). Hemoglobin levels and the rate of erythropoietin-stimulating agent users were similar. However, the prescribed erythropoietin-stimulating agent dose (31.6±27.5 vs. 47.3±45.2 U/kg/week, P<0.05) and the erythropoietin response index (2.90±2.73 vs. 4.51±4.48 U/kg/week/Hb, P=0.001) were lower in statin users compared with statin nonusers. On stepwise multiple regression analysis, gender, high-sensitive C-reactive protein, duration of hemodialysis, serum ferritin, and statin use were independent determinants of the erythropoietin responsiveness index. Our results suggest that statin treatment leads to lower inflammation and improves hematopoiesis in hemodialysis patients.     

Sorption Phenomena in Packaged Foods: Factors Affecting Sorption Processes in Package–Product Systems

Sorption process can readily occur from many foods. The sorption behaviours result in loss of food quality and shelf life of the packaged foods by altering the aroma compound profile. Although the intensity of the aroma of a packaged foodstuff depends on the vapour pressure, the interaction of the volatile organic moieties with other food constituents and the aroma barrier characteristics of the package, the nature of the aroma is also imperative in determining the extent of sorption. Sorption properties are largely determined by packaging characteristics, flavour molecules properties, food matrix composition and environmental conditions. The chemical composition, chain stiffness, morphology, polarity and crystallinity of the polymer influence flavour absorption as much as the chemical composition, concentration and polarity of the flavour compounds, as well as the presence of other chemical constituents. External factors such as duration of storage, relative humidity, temperature and the presence of other food components can also affect the solubility of aroma compounds in packaged foods. Factors relating to both chemical and physical structure of flavour, food and packaging influence the degree of sorption and also the sorption pattern. Sorption from the packaged foods is of major concern in the selection and use of plastic packaging materials for food packaging. The present review highlights some of the major factors influencing the sorption process. The scientific principles related to sorption are reviewed and distinguished. Copyright © 2011 John Wiley & Sons, Ltd.     

Molecular absorption and photodesorption in pristine and functionalized large-area graphene layers

We studied the photodesorption behavior of pristine and nitric acid (HNO(3)) treated graphene layers fabricated by chemical vapor deposition (CVD). The decrease in electrical conductivity and a negative shift of the Dirac point in graphene layers illuminated with ultraviolet light are caused by molecular photodesorption, while the UV illumination does not degrade the carrier mobility of graphene layers. When graphene layers were treated with concentrated HNO(3), the photodesorption-induced current decrease became less significant than for pristine graphene layers. We suggest this is due to the passivation of oxygen-bearing functionalities to CVD grown graphene structural defects by HNO(3) functionalization, which prevents the further absorption of gas molecules. Our results provide a new strategy for stabilizing the electrical performance of CVD grown large-area graphene layers for applications ranging from nanoelectronics to optoelectronics.     

Chemical composition,antioxidant, and enzyme inhibitory activities of the essential oils of three <Emphasis Type="Italic">Phlomis</Emphasis> species as well as their fatty acid compositions

This study aimed to investigate the chemical composition, antioxidant, and enzyme inhibitory activities of the essential oils of Phlomis armeniaca WILLD., P. nissolii L., and P. pungens WILLD. var. pungens as well as their fatty acid contents. Germacrene D was found as the major compound in the oils (24.7, 15.1, and 7.2%, respectively). Additionally, n-hexadecanoic acid, hexahydrofarnesyl acetone, β-caryophyllene, and linalool were the other main compounds in the oils. Among the fatty acids, C18:3 ω3 and C18:2 ω6 were determined in high quantities in P. armeniaca (23.14 and 18.01%, respectively) and P. pungens var. pungens (24.64 and 17.51%, respectively). The essential oils of P. armeniaca and P. pungens var. pungens showed remarkable antioxidant and metal chelating activities as well as great reducing power potentials. These oils also showed a moderate scavenging effect on ABTS radicals. The oils also exhibited various degrees of inhibitory activities on AChE, BChE, α-amylase, α-glucosidase, and tyrosinase.     

Impact of lighting arrangements and illuminances on different impressions of a room

This study explores whether different lighting arrangements (general lighting, wall washing and cove lighting) and different illuminances (500 and 320 lux) could affect the perception of the same space. An experimental study was conducted to investigate how the qualitative aspects of space (the impressions of a space) could be enhanced with lighting. Hundred participants were first asked to choose the most suitable lighting arrangement for each impression (clarity, spaciousness, relaxation, privacy, pleasantness and order) under the 500 lux illuminance. In the second stage, they were asked to compare the two illuminances (500 and 320 lux) for the lighting arrangement they selected in the first stage. There was a statistically significant relation between impressions and lighting arrangements, also between impressions and lighting levels. Thus, different lighting arrangements and lighting levels could be used to enhance the clarity, spaciousness, relaxation, privacy, pleasantness and order of a room. The results of this study found most suitable lighting arrangements with their illuminances for each impression, which is reported in the paper.     

Behaviour of reinforced and concrete-encased composite columns subjected to biaxial bending and axial load

An experimental investigation of the behaviour of reinforced concrete columns and a theoretical procedure for analysis of both short and slender reinforced and composite columns of arbitrarily shaped cross section subjected to biaxial bending and axial load are presented. In the proposed procedure, nonlinear stress–strain relations are assumed for concrete, reinforcing steel and structural steel materials. The compression zone of the concrete section and the entire section of the structural steel are divided into adequate number of segments in order to use various stress–strain models for the analysis. The slenderness effect of the member is taken into account by using the Moment Magnification Method. The proposed procedure was compared with test results of 12 square and three L-shaped reinforced concrete columns subjected to short-term axial load and biaxial bending, and also some experimental results available in the literature for composite columns compared with the theoretical results obtained by the proposed procedure and a good degree of accuracy was obtained.     

A new flavone from antioxidant extracts of Pistacia terebinthus

Acetone and methanol extracts of the fruits of Pistacia terebinthus L. subsp. terebinthus L. were studied for their antioxidant activity by investigating their total phenolic and flavonoid contents, β-carotene bleaching potential, DPPH radical scavenging effect, scavenging activity on superoxide anion radical, reducing power, and metal chelating effect on ferrous ion. Both extracts showed very similar chemical profile by checking on TLC plates, and exhibited high scavenging activity on superoxide anion radical and DPPH radical. Due to these similarities they were combined and fractionated on a silica gel column for their constituents, and the most active three fractions in DPPH assay were purified to afford a new flavone 6′-hydroxyhypolaetin 3′-methyl ether (1) besides a group of known flavonoids apigenin, luteolin, luteolin 7-O-glucoside, quercetin, quercetagetin 3-methyl ether 7-O-glucoside, isoscutellarein 8-O-glucoside. Their structures were established by UV, UV shift reagents, and ¹H NMR spectroscopic techniques. Antioxidant activity of the new flavone was investigated by β-carotene bleaching and DPPH radical scavenging activity methods, and it showed a high activity in the first system, but not so good in the latter.     

Digital memory device based on tobacco mosaic virus conjugated with nanoparticles

Nanostructured viruses are attractive for use as templates for ordering quantum dots to make self-assembled building blocks for next-generation electronic devices. So far, only a few types of electronic devices have been fabricated from biomolecules due to the lack of charge transport through biomolecular junctions. Here, we show a novel electronic memory effect by incorporating platinum nanoparticles into tobacco mosaic virus. The memory effect is based on conductance switching, which leads to the occurrence of bistable states with an on/off ratio larger than three orders of magnitude. The mechanism of this process is attributed to charge trapping in the nanoparticles for data storage and a tunnelling process in the high conductance state. Such hybrid bio-inorganic nanostructures show promise for applications in future nanoelectronics.