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Ternary blends based on isotactic polypropylene (iPP) modified by polyamide 6 (PA6) and ethylene-propylene-diene terpolymer (EPDM) were prepared and their rheological properties were studied. The total content of dispersed phases was kept fixed at 30 wt%. The goal was to investigate the effect of blend composition and compatibilization process using PP- g-MA on the dynamic viscoelastic properties of PP/PA6/EPDM ternary systems. Then, attempts were made to correlate the viscoelastic response of the blends with their morphological texture as examined by SEM technique. Different rheological behaviors were observed depending on the dispersed phase(s) type, concentration and alteration of interfacial interaction between the phases. In the blends containing PA6 phase, compatibilization process led to a significant change in the morphology of the blend with a subsequent change in the viscoelastic properties, especially at low-frequency regions. Rheological analysis revealed a deviation from liquid-like behavior for certain binary and ternary systems which were dependent on the PA6 and EPDM contents and the microstructure of the blends as well. In the case of ternary blends, separated-type morphology was observed in consistent with morphology predicted by spreading coefficient concept. The relationship between the morphology and relaxation process of the individual particles was also discussed. [ABSTRACT FROM AUTHOR]

Morphological, rheological and mechanical properties of the polypropylene (PP) and poly(styrene-co-acrylonitrile) (SAN) blend containing poly(styrene- b-butadiene- b-styrene) (SBS) triblock copolymer (ranging from 0 to 20 wt%) were studied by scanning electron microscopy (SEM), small amplitude oscillatory shear analysis, and both tensile and impact tests, respectively. SEM observations showed that SBS reduced the diameter of the SAN dispersed particles as well as improved the adhesion between the matrix and the dispersed phase. Close examination of SEM micrographs further revealed that the dispersed phase domains were complex aggregates of SAN particles enveloped and joined together with the SBS compatibilizer in the PP matrix. The variation of the dynamic rheological parameters, including dynamic moduli ( G′ and G″), complex viscosity ( $$ \eta^{ * } $$ ), loss factor (tan δ), together with Cole-Cole diagrams, with blend composition particularly at low frequency regions were determined to evaluate the interfacial activity of SBS copolymer. A specific viscoelastic phenomenon, i.e., 'the second plateau', appeared at low frequencies for PP/SAN blend containing 20 wt% of SBS and exhibited a certain dependence on the SBS amount and dispersion state in the matrix. This phenomenon was attributed to the formation of aggregate structure between SAN particles and SBS triblock copolymer. Finally, the results of uniaxial tensile and Charpy impact tests conducted on both unnotched and notched specimens indicated that in PP/SAN blend, SBS functions as both compatibilizer and toughening agent. [ABSTRACT FROM AUTHOR]

This work examines the heat transfer between two fixed contacting specimens in order to estimate the time-varying thermal contact conductance. An inverse heat conduction method is presented. A well-known technique called extrapolation method is also utilized to obtain the results by using data taken from an experiment. The results achieved by the inverse and linear extrapolation methods are in good agreement. In addition, a steady-state analysis has been performed by using the commercial software based on the finite element method and an error analysis shows that the extrapolation method is superior in this analysis. [ABSTRACT FROM AUTHOR]

The essential work of fracture (EWF) method was employed to determine the fracture toughness of SAN/PB-g-SAN blends with the compositions of 65/35-0/100. It was found that the plane stress EWF approach is applicable for different SAN/PB-g-SAN blends. During EWF tests, three different types of load-displacement curves were recorded, depending on the blend composition. For the samples containing rubbery phase of 35-65 wt% crack growth occurred immediately after full ligament yielding. Further increase in rubber content and for the samples with 75 and 85 wt% of rubbery phase, the onset of crack growth was preceded by the formation of necking zone in the form of a sharp load drop after full ligament yielding. For the sample with the composition of 0/100, strain hardening behavior was observed without any sign of neck formation. The specific essential work of fracture (EWF) w increased at first with the increase of PB-g-SAN wt% and then decreased with further increasing amount of rubbery phase. The maximum value of w was observed for the blend with 75 wt% of PB-g-SAN. The specific non-essential work of fracture βW increased with increasing of rubbery phase concentration. The analyzing of yielding and necking/tearing components of essential and non-essential parameters showed that for the samples containing 55 wt% and higher of rubbery phase, $$ w_{\text{e,nt}} \succ w_{\text{e,y}} $$and $$ \beta_{\text{nt}} w_{\text{p,nt}} \succ \beta_{\text{y}} w_{\text{p,y}} $$, indicating that a majority of fracture energy was dissipated in the necking and tearing stages of fracture process. Finally, it is shown that w values can be predicted via COD values. [ABSTRACT FROM AUTHOR]

The mechanical properties of SAN/PB-g-SAN blends of different compositions under uniaxial tensile tests were studied. Matrix ligament thickness (MLT) concept was employed to correlate microscopic deformations with macroscopic mechanical response. It was found that, the experimental values of the blends moduli are in a good agreement with the theoretical values obtained from Takayanagi and mixture rules in parallel models. The MLTs in which transition from brittle-to-ductile and from ductile-to-rubbery occur were determined according to interparticle distance model. Fractography studies of the samples with MLT values greater than brittle to ductile transition showed that rubber particles act as craze initiators rather than craze terminators. Due to poor overlapping of stress fields around the particles, no extensive shear yielding took place during the fracture process, leading to unstable macroscopic behavior. For the samples with MLTs smaller than brittle-ductile transition, a necked region developed. The stability of necked region increased with PB-g-SAN content, which resulted in improved post yield deformation stability. This process was accompanied by the participation of larger volume of material in the deformation process and strong overlapping of the stress field around the particles, which facilitated matrix shear yielding. Based on macroscopic response, this delocalized deformation manifested itself by a gradual decrease in load drop after yielding point. For the samples with PB-g-SAN content higher than 75 wt%, the great reduction in MLT and direct interconnection between the neighbor rubber particles caused the appearance of rubbery behavior. These results were also confirmed by analyzing of the fractured surfaces. [ABSTRACT FROM AUTHOR]

In the present paper a few comments on the paper "Fracture study of the composite using essential work of fracture method: PP-SEBS-g-MA/E1 clay" Materials and Design 53 (2014) 741-748, have been discussed. The comments are mainly focused on the methodology employed for evaluation of fracture parameters. The EWF method has been used for characterization of the fracture parameters of all the samples, while it seems that some of the samples did not satisfy the main prerequisites of the EWF approach. With this respect the obtained data and discussed results are questionable. [ABSTRACT FROM AUTHOR]

Abstract: Two new designs of wind towers were tested side by side with a conventional wind tower in the city of Yazd, Iran. All the towers were of identical dimensions. The two new designs were one with wetted column, consisting of wetted curtains hung in the tower column, and the other one with wetted surfaces, consisting of wetted evaporative cooling pads mounted at its entrance. The air temperature leaving the wind towers with evaporative cooling provisions were much lower than the air temperature leaving the conventional design, and its relative humidity much higher. The air-flow rate was reduced slightly in these new towers. It was found that the wind tower with wetted column performs better with high wind speeds whereas the tower with wetted surfaces performs better with low wind speeds. It is recommended that these new designs of wind towers should be manufactured in different sizes and incorporated in the designs of new buildings. They can replace the evaporative coolers currently employed in Iran, and other hot arid regions, with considerable saving in electrical energy consumption. [Copyright &y& Elsevier]

The main purpose of the present work was to study the phase morphology, mechanical properties and fracture behavior of PP/PA6/(EPDM:EPDM-g-MA) (70/15/15) ternary blends with various rations of EPDM:EPDM-g-MA. The mechanical properties of the blends were examined technique tensile and impact tests. The fracture properties were characterized in detail by the essential work of fracture (EWF) approach. The test results the essential work of fracture for ternary blends with different weight rations indicated that the full ligament yielding took place before the onset and crack propagation for all blends with different weight ratio of EPDM:EPDM-g-MA. The energy partitioning method was also employed to determine energy dissipation in the stage of yielding, necking and tearing. The results revealed that with increasing of the EPDM-g-MA displacement to the point of failure in a constant ligament reduced. The specific non-essential work of fracture β W p and β n t. W p , n t decreased with increasing of EPDM-g-MA content that such an increase is confirmed according to the force-displacement curves. Whereas, the specific non-essential work of fracture β y. W p , y increased with increasing of EPDM-g-MA content. As well as the yielding component of W e and W e , n decreased with increasing of EPDM-g-MA content. While the yielding component of W e , y increased with increasing of EPDM-g-MA content. • The fracture properties were characterized in detail by the essential work of fracture (EWF) approach. • The energy partitioning method was also employed to determine energy dissipation in the stage of yielding, necking and tearing. • With increasing of the EPDM-g-MA displacement to the point of failure in a constant ligament reduced. • The specific non-essential work of fracture β W p and β n t. W p , n t decreased with increasing of EPDM-g-MA content. • The specific non-essential work of fracture β y. W p , y increased with increasing of EPDM-g-MA content. [ABSTRACT FROM AUTHOR]

The effect of microstructural evolution with hydrophilic-nanosilica (SiO2) concentration, ranging from 0 to 5 wt%, on mechanical properties and deformation micromechanisms of PP/EPDM/SiO2 (80/20/x) ternary blend-nanocomposites was investigated. Morphological observations revealed that, SiO2 nanoparticles tend to localize either around the dispersed EPDM particles or at the PP/EPDM interface, promoting the formation of three dimentional network-like EPDM/SiO2 composite structures dispersed in the PP matrix, especially at higher SiO2 loadings. This type of dispersion state was further confirmed by the rheological analysis. Synergistic toughening effect of soft EPDM particles and rigid SiO2 particles under Izod impact test was observed in these ternary systems, so that the materials with a better balance of stiffness/toughness were achieved. The results demonstrated that the extent of impact toughness increase is higher, where a large amount of the SiO2 nanoparticles surrounded the EPDM dispersed particles distributed in the PP matrix. This significant increase was attributed to the change in the size of stress concentration region and evolution of stress distribution throughout the material. The failure mechanisms were studied, and the underlying toughening micromechanisms were proposed. [ABSTRACT FROM AUTHOR]

Morphology, mechanical properties and fracture behavior of polypropylene/polyamide 6/ethylene polypropylene diene monomer graft maleic anhydride (PP/PA6/EPDM-g-MA) ternary blends containing various amounts of the EPDM-g-MA rubbery phase (from 0 to 9 wt%), with special attention to the structure–property relationships through the core–shell morphology development, were studied. The fracture surface, deformation micro-mechanisms and mechanical properties of the blends were examined using field emission scanning electron microscopy technique, tensile and impact tests, respectively. The fracture properties were characterized in detail by the linear elastic fracture mechanics method. The fracture energy (GC), fracture toughness (KIC) and impact strength were improved monotonically up to some EPDM-g-MA content, above which the characteristics were appreciably enhanced. These results were attributed to an alteration of this morphology from dispersion of PA6/EPDM-g-MA core–shell particles at low EPDM-g-MA contents to the aggregated structure of core–shell particles at higher EPDM-g-MA contents. The micro-void formation via activation of internal cavitation or debonding of the rubbery phase was found to be responsible for the stress whitening phenomenon that occurred during the impact fracture process and, hence, increased impact toughness. [ABSTRACT FROM AUTHOR]

Almost exactly 100 years ago Osborne and colleagues demonstrated that restricting the food intake of a small number of female rats extended their lifespan. In the 1930s experiments on the impact of diet on lifespan were extended by Slonaker, and subsequently McCay. Slonaker concluded that there was a strong impact of protein intake on lifespan, while McCay concluded that calories are the main factor causing differences in lifespan when animals are restricted (Calorie restriction or CR). Hence from the very beginning the question of whether food restriction acts on lifespan via reduced calorie intake or reduced protein intake was disputed. Subsequent work supported the idea that calories were the dominant factor. More recently, however, this role has again been questioned, particularly in studies of insects. Here we review the data regarding previous studies of protein and calorie restriction in rodents. We show that increasing CR (with simultaneous protein restriction: PR) increases lifespan, and that CR with no PR generates an identical effect. None of the residual variation in the impact of CR (with PR) on lifespan could be traced to variation in macronutrient content of the diet. Other studies show that low protein content in the diet does increase median lifespan, but the effect is smaller than the CR effect. We conclude that CR is a valid phenomenon in rodents that cannot be explained by changes in protein intake, but that there is a separate phenomenon linking protein intake to lifespan, which acts over a different range of protein intakes than is typical in CR studies. This suggests there may be a fundamental difference in the responses of insects and rodents to CR. This may be traced to differences in the physiology of these groups, or reflect a major methodological difference between ‘restriction’ studies performed on rodents and insects. We suggest that studies where the diet is supplied ad libitum , but diluted with inert components, should perhaps be called dietary or caloric dilution, rather than dietary or caloric restriction, to distinguish these potentially important methodological differences. [ABSTRACT FROM AUTHOR]

The process of thermocapillary bubbles rising in a rotating 3D cylinder in zero gravity was analysed and presented numerically with the aid of computational fluid dynamics (CFD) by means of the volume of fluid (VOF) method. Calculations were carried out to investigate in detail the effect of the rotational speed of the hosted liquid on the trajectory of both single and group bubbles driven by the Marangoni force in zero-gravity conditions. For rotational speeds from 0.25 to 2 rad/s, bubble displacement with angular motion was found to be directed between the hotter surface and the rotational axis. This is contrary to the conventional bubble flow from areas of high pressure to low pressure, radial direction, or from cold to hot regions, axial direction. The results demonstrate that for the ratio of rotational speeds to the thermocapillary bubble velocity larger than unity, the surface tension gradient is the dominant force and the bubble motion towards the hotter. On the other hand, for ratio less than 1, the bubble motion is dominated and is significantly affected by centrifugal force. As rotation speed increases, the amount of deflection increases and the Marangoni effect vanishes. The current study is novel in the sense that single- and multi-bubble motion incorporating thermocapillary forces in a rotating liquid in a zero-gravity environment has never been numerically investigated. [ABSTRACT FROM AUTHOR]

Performance of a Heller cooling tower under wind conditions has been investigated by measuring wind velocity and its direction around the tower and inlet and outlet water flow rates and temperatures. Results show that air suction at the tower prevents flow separation at its periphery. The tower front cooling sectors experience better airflow distribution compared to sectors parallel to wind direction, which improves their thermal performance by about 20% compared to still-air conditions. Airflow pattern around the tower at different distances shows that wind tangential velocity at corner sectors is four times the velocity at the reference point, decreasing air pressure and tower suction. [ABSTRACT FROM AUTHOR]

Assessment of validity of the Draw A Story test was the aim of this study. The sample consisted of 137 elementary students (53 girls and 84 boys) recruited from fourth and fifth grades, and were categorized into two groups of aggressive and withdrawn based on assessments. They were given the Draw A Story test (DAS). According to the results, the differences between the two groups were significant for self image (p<.04) and non significant for the emotional content of DAS. The aggressive group showed stronger self image in comparison to the other group. Aggressive boys showed a stronger self image while the withdrawn children showed a weaker self image (p<.04). Aggressive and withdrawn girls had higher mean scores in the emotional content than boys, whereas the aggressive boys showed a weaker emotional content (p<.02). The range of positive to negative response frequencies were significantly different for both groups and both groups had the highest response frequency in emotional content in the range of moderately negative. The range of self image response frequencies in the aggressive group was significantly different and positive response had the highest frequency. The range of self image response frequencies in the withdrawn children was significantly different, and the unpleasant and negative responses had the highest frequency. Content analysis of the aggressive stories showed a high engagement ratio of aggression components with the highest frequency of murdering and killing imageries, while in the withdrawn children content analysis indicated the high engagement ratio with the highest frequency of components such as loneliness, fear and anxiety. These results indicate that Draw a Story Test is a valid instrument for discriminating aggressive and withdrawn children from normal subjects. [ABSTRACT FROM AUTHOR]

Tumors such as prostate, small cell lung cancer, breast, gastric and colon cancer are known to overexpress receptors to bombesin (BBN). In this study, a new bombesin analogue was labeled with Tc via HYNIC and tricine/EDDA as coligands and investigated further. HYNIC-GABA-Bombesin (7-14) NH was synthesized using a standard Fmoc strategy. Labeling with Tc was performed at 100 °C for 10 min and radiochemical analysis involved ITLC and HPLC methods. The stability of radiopeptide was checked in the presence of humane serum at 37 °C up to 24 h. The receptor bound internalization and externalization rates were studied in GRP receptor expressing PC-3 cells. Biodistribution of radiopeptide was studied in nude mice bearing PC-3 tumor. Labeling yield of >98% was obtained corresponding to a specific activity of ~2.6 MBq/nmol. Peptide conjugate showed good stability in the presence of human serum. The radioligand showed high and specific internalization into PC-3 cells (14.63 ± 0.41% at 4 h). In biodistribution studies, a receptor-specific uptake was observed in GRP-receptor-positive organs so that after 4 h the uptakes in mouse tumor and pancreas were 1.31 ± 0.18 and 1.2 ± 0.13% ID/g, respectively. [ABSTRACT FROM AUTHOR]

In this work, peculiarities of mechanical bending and deformation rate of silicon wafers under the influence of applied external forces have been studied. It has been shown that, for all investigated samples, there are three characteristic sections with various slopes irrespective of the types of operation, orientation and thickness of the wafers. By increasing the applied force, the rate of deformation rises, reaches a maximum, and then starts to decrease not monotonically, but spasmodically by further increase of the force. Experimental results are discussed on the base of the creation of dislocations and it is shown that, there is excellent correlation between the density of dislocations and sposmodic decrease of deformation rate. The analysis of the obtained results confirms the availability of plastic deformation and its inclination to localization during deformation process at room temperature. It should be added that, the sposmodic decrease of deformation rate, can be viewed as a self-organized deformable medium. [Copyright &y& Elsevier]

The goal of this study was to investigate the prevalence of adiposity in a sample of 35-65 years old individuals from Mashhad in North Eastern Iran, and to ascertain the socioeconomic factors contributing to obesity. The MASHAD study was initiated in 2010 and is a longitudinal cohort study of 9765 individuals aged 35-65 years old. It used a stratified cluster randomized sampling design. Anthropometric measurements [height, weight and waist circumference (WC)] were measured by standard methods. The criteria for under-weight, normal-weight, overweight, and obesity were a BMI of 18.5>, 18.5 to 24.9, 25 to 29.9, 30< (kg/m2), respectively. Abdominal obesity was defined as WC ⩾102 cm in men and WC ⩾88 cm in women and obesity was defined as BMI ⩾30. Logistic regression analysis was used to determine the adjusted odds ratio (OR) and chi-square tests were used to determine whether different categories of demographic and lifestyle variables were associated with different degrees of adiposity. The overall prevalence of obesity and overweight were 30.9% and 42.8% respectively. The overall prevalence of central obesity was 46.7%. The prevalence of obesity in women was higher than in men (P < 0.0001). There was an inverse relationship between the risk of obesity and increasing socioeconomic status (P < 0.0001). Adiposity is prevalent in Mashhad, and appears to be particularly common in women. This may be due to the high levels of physical inactivity in the population as a whole and among women in particular. [ABSTRACT FROM AUTHOR]

Background/objectives: Obese infants are more susceptible to develop adulthood obesity and its related comorbidities. Previous studies have shown the presence of hormones and growth factors in maternal breast milk that may influence infant adiposity. The aim of this study was to investigate differences in concentrations of three hormones and two growth factors in the breast milk of mothers with obese and non-obese infants.Subjects/methods: In this cross-sectional study, 40 mothers with overweight or obese infants (weight for length percentile >97) and 40 age-matched mothers with normal-weight infant (-10 < weight for length percentile < 85) who were between 2 and 5 months of age were enrolled. Anthropometric indices of infants and mothers were measured by routine methods. Breast milk concentrations of ghrelin and adiponectin, leptin, epithelial growth factor (EGF) and insulin-like growth factor-1 (IGF-1) were measured using enzyme-linked immunosorbent assay methods.Results: The mean breast milk concentration of ghrelin was higher in mothers with normal-weight infants, 137.50 pg/ml, than in mothers with obese infants, 132.00 pg/ml (P=0.001). This was also true regarding the concentration of EGF in mothers with (0/04 ng/ml) and without (0/038 ng/ml) normal-weight infants (P=0.01). No significant differences were observed in concentrations of leptin, adiponectin and IGF-1 between two groups (P > 0.05). There was also a significant positive correlation between EGF and ghrelin in both groups.Conclusions: This study revealed that there was a correlation between ghrelin and EGF level in breast milk of mothers with obese and non-obese infants, suggesting a possible regulatory effect of these two hormones on weight in infants. [ABSTRACT FROM AUTHOR]

Background/Objectives:Obese infants are more susceptible to develop adulthood obesity and its related comorbidities. Previous studies have shown the presence of hormones and growth factors in maternal breast milk that may influence infant adiposity. The aim of this study was to investigate differences in concentrations of three hormones and two growth factors in the breast milk of mothers with obese and non-obese infants.Subjects/Methods:In this cross-sectional study, 40 mothers with overweight or obese infants (weight for length percentile >97) and 40 age-matched mothers with normal-weight infant (−100.05). There was also a significant positive correlation between EGF and ghrelin in both groups.Conclusions:This study revealed that there was a correlation between ghrelin and EGF level in breast milk of mothers with obese and non-obese infants, suggesting a possible regulatory effect of these two hormones on weight in infants. [ABSTRACT FROM AUTHOR]

Attempts were made to study the effect of reactive compatibilization via Friedel-Crafts alkylation reaction, using AlCl as a catalyst, on rheology, morphology, and mechanical properties of polyethylene/polystyrene (PE/PS) blends. The results of linear viscoelastic measurements in conjunction with the results of the mixing torque variation indicated that PS showed much more degradation than that of PE in the presence of AlCl. It was also found that while for PE-rich blends, the viscosity, and storage modulus increased by reactive compatibilization, they decreased for PS-rich blends. The variation of viscosity and storage modulus for 50/50 blend was found to be dependent on frequency ranges showing the competitive effects of PE- g-PS copolymer formation and PS degradation. The results of morphological studies showed that reactive compatibilization decreased the particle size and particle-size distribution broadness because of in situ graft copolymer formation. Reactive compatibilization enhanced the tensile strength and elongation at break for PE-rich blends. It was demonstrated that there is a close interrelationship between rheology, morphology, and mechanical properties of reactive compatiblized PE/PS blends. It was also demonstrated that rheological behaviors have a reliable sensitivity to follow the structural and morphological changes during compatibilization process, so that, those information can be used to predict the morphology as well as mechanical properties of the blends. [ABSTRACT FROM AUTHOR]

PR81 is a monoclonal antibody that binds with high affinity to MUC1, which is over expressed on breast and other tumors. The objective of this study was to evaluate the application of this antibody against MUC1 as a radioimmunotherapeutical agent. Monoclonal antibody (PR81) against MUC1 was prepared, characterized, purified, and labeled with ^{131}I. The immunoreactivity of radiolabeled mAb PR81with MUC1 (the native protein), BSA-P20 (a 20 amino acid corresponding the tandem repeat of MUC1) and MCF7 cell line were performed by RIA. In vitro stability of radiolabeled mAb in human serum was determined by thin layer chromatography (TLC). Cell toxicity and in vitro internalization studies were performed with the MCF7 cell line, and the tissue biodistribution of the radioiodinated PR81 was evaluated in normal BALB/c mice at 4, 24 and 48 hrs. The tumor imaging was performed in BALB/c mice with breast xenograft tumors at 24 and 72 hr after the complex injection. The labeling efficiency was found to be 59.9% ± 7.9%. MAb- ^{131}I conjugates showed high immunoreactivity towards MUC1 protein, BSA-P20 and MCF7 cell line. In vitro stability of the labeled product in human serum was found to be more than %50 over 24 hr. Cell toxicity and in vitro internalization studies showed that the mAb-^{131}I conjugate inhibited 80% growth of the MCF7 cultured cell lines in vitro in a high concentration and up to %60 of the conjugate internalized after 24 h. Biodistribution studies were performed in normal BALB/c mice at 4, 24 and 48 hrs post-injection and no important accumulation was observed in vital organs. The tumors were visualized with high sensitivity after 24 and 72 hr in radioimmunoscintographical studies. These results show that the new radiopharmaceutical may be considered as a promising candidate for therapy of breast cancer. [ABSTRACT FROM AUTHOR]