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Dense suspensions can exhibit shear thickening in response to large deformation. A consensus has emerged over the past few years on the formation of force networks, that span the entire system size, that lead to increased resistance to motion. Nonetheless, the characteristics of these networks are to a large extent poorly understood. Here, force networks formed in continuous and discontinuous shear thickening dense suspensions (CST and DST, respectively) are studied. We first show the evolution of the network formation and its topological heterogeneities as the applied stress increases. Subsequently, we identify force communities and coarse grain the suspension into a cluster network, and show that cluster-level dynamics are responsible for stark differences between the CST and DST behavior. Our results suggest that the force clusters formed in the DST regime are considerably more constrained in their motion, while CST clusters are loosely connected to their surrounding clusters.

We report experimental and computational observations of dynamic contact networks for colloidal suspensions undergoing shear thickening. The dense suspensions are comprised of sterically stabilized poly(methyl methacrylate) hard sphere colloids that are spherically symmetric and have varied surface roughness. Confocal rheometry and dissipative particle dynamics simulations show that the shear thickening strength scales exponentially with the scaled deficit contact number and the scaled jamming distance. Rough colloids, which experience additional tangential and rolling constraints, require an average of 1.5 - 2 fewer particle contacts as compared to smooth colloids, in order to generate the same shear thickening strength. This is because the surface roughness enhances geometric friction in a way that the rough colloids do not experience a large change in the free volume near the jamming point. In contrast, smooth colloids must undergo significant reduction in the free volume to support an equivalent shear stress. The available free volume for different colloid roughness is related to the deficiency from the maximum number of nearest neighbors at jamming under shear. Our results further suggest that the force per contact is different for particles with different morphologies.

Here, a number of synthesized and commercial nano-sorbents including graphene (G), multi-wall carbon nanotube (MWCNT), graphene oxide (GO), reduced graphene oxide (rGO) and magnetic nanoparticles anchored on GO (Fe 3 O 4 NPs@GO) followed by graphite (Gt) powder were employed for paclitaxel pre-purification from callus culture-derived extract of Taxus baccata . Based on our preliminary work, rGO and Fe 3 O 4 NPs@GO exhibited the maximum potential, not only to remove impurities, but also to ameliorate taxol purity. According to the results of response surface methodology (RSM) developed for the superior nano-sorbent (i.e., Fe 3 O 4 NPs@GO), for both proposed quadratic polynomial models, statistically substantial relationships obtained between the actual and predicted values (‎p 3 O 4 NPs@GO nano-sorbent and RSM can be recommended as a simple, cost-effective and fast route for sorbent-assistant pre-purification investigations of paclitaxel.

St. John’s wort (Hypericum perforatum L.) is the most important species of the genus Hypericum and produces a wide range of chemical constituents including essential oil. Regarding advantages of in vitro culture techniques in production of desired metabolites, the present study was aimed to investigate volatile constituents of H. perforatum shoots cultured in different basal media. Shoot cultures were established by culturing six nodes of aseptic plants in three liquid media including MS (Murashige and Skoog), B5 (Gamborg B-5) and half-strength B5 containing 30 g L-1 sucrose and 0.5 mg L-1 BA (6-benzyladenine). According to the results, growth and profile of volatile constituents of cultured shoots were affected by the type of medium used and shoots cultured in the B5 medium exhibited the highest growth which was reached to 42.95 g flask-1. On the other hand, 44 components were totally identified by GC-FID and GC-MS analysis of essential oils of cultured shoots. Decane (27.7%), menthol (8.9%), methyl decanoate (4.6%) and β-elemene (4.6%) were the major volatile constituents of the shoots cultured in MS medium, while eudesma4(15),7-dien-1-β-ol (8.1-7.5%), thymol (7-7.2%) and 1,4-trans-1,7-trans-acorenone (5.2-5.5%) were found as the principal components of shoots cultured in B5 and half-strength B5 media.

Background Study of antioxidant vitamin consumption behavior, especially in high-risk groups with high exposure to toxic metals to reduce metal toxicity, is emphasized. This study aims to examine the structural relationships between knowledge, protection motivation theory constructs, and vitamin E and C consumption behavior among cement factory workers. Methods Protection motivation theory and food frequency questionnaires were completed by 420 factory workers. Data were subjected to structural equation modeling to examine associations between knowledge, protection motivation theory constructs, and vitamin E and C consumption behavior. Efficacy of current recommended models was also explored. Results Structural equation modeling showed high explained variance within the constructs of protection motivation theory for vitamin E and C consumption behavior and intention (56–76%). The overall fit of the structural models was acceptable for both vitamin E and C behavior. Knowledge, self-efficacy, response efficacy, and perceived vulnerability predicted intention, which in turn predicted vitamin consumption behavior. Significant relationships between knowledge and self-efficacy, response efficacy, perceived vulnerability, and perceived severity were also found, while self-efficacy and response efficacy showed significant relationships with vitamin E and C consumption behavior. Conclusions Considering that response efficacy, self-efficacy, and intention showed as strong predictors of vitamin E and C consumption behavior, specific attention should be paid to coping appraisals and intention when designing intervention plans. Additionally, establishing the predicting role of knowledge for protection motivation theory constructs and protective behaviors should be integrated into intervention programs.

Introduction: Various studies have suggested the protective role of antioxidant vitamins such as vitamin C and E against toxic injury and disease resulting from toxic metals. Thus, studying the antioxidant vitamins consumption behaviour, particularly in high-risk groups such as factory workers with high exposure to toxic metals is emphasised. Aim: This study examined the effects of educational interventions based on the Protection Motivation Theory (PMT) among cement factory workers after intervention and six months of follow-up. Materials and Methods: Cement factory workers were randomly assigned into three groups: indirect (n=70), face-to-face (n=70) and control (n=70). The content of face-to-face interventions included multimodal lectures with powerpoint presentations, discussion, questions and answers, individual counselling sessions, and educational pamphlets and booklets. The indirect group received recently designed educational content through pamphlets and booklets. Workers completed PMT questionnaire and Food Frequency Questionnaire (FFQ) at baseline, post-intervention, and at the six-month follow-up. Results: Results showed significant positive changes on all PMT constructs, knowledge, and vitamins E and C consumption in both intervention groups at immediate post-intervention and at six month follow-up. Knowledge and intention remained higher in face-to-face groups than in indirect group and higher maintenance was also observed in relation to vitamins and C consumption in the face-to-face group. Conclusion: Findings of this study indicated the PMT intervention, particularly face-to-face intervention, is sound and can be performed for other protective dietary behaviours, such as other antioxidants consumption.

Depression is one of the most common psychiatric disorders. Despite the prevalence and serious effects of depression, the pathological studies of depression are still preliminary. The main reason for this is limited access to valid animal models. Using animal models, the underlying molecular changes and causal relationship between environmental or genetic changes and depression can be studied, which provides a better insight into the pathology of depression. The role of stress as a key factor in the etiology of depression is emphasized. Because of the importance of stress in creating depression disorder in this study, animal models of stress - based depression have been investigated. Animal models of stress - based depression are:1- learned helplessness (LH) model 2- Models based on early-life stress 3- chronic mild stress (CMS) model 4- Social defeat stress model. Studies show that exposure to early life stress can continuously alter DNA methylation in the brain of adult mice or rodents. In this regard, we can mention the role of methylation of Nr3c1 gene in parts of the hippocampus of the brain, indicating that epigenetic changes may play a role in depressive like behavior. Also, an unpredictable chronic mild stress model in rodents shows that significantly reduced diffusion of astrocyte cell gap and abnormal ultrastructure gap junction in the prefrontal cortex (PFC) and low levels of adenosine triphosphate (ATP) in the mouse brain, are the cause of depressive like behavior.

Attempts were made here to apply a modified analytic hierarchy process (AHP) approach based on refinement assay of dominated alternatives in monitoring the most reliable callus maintenance media (supplemented with l-glutamine and Casamino acid) of Taxus baccata callus cultures in terms of five criteria. Generally, regarding stem-derived calli, 6 out of 18 maintenance media were nominated as non-dominated alternatives, and following AHP ranking test Casamino acid-based media (i.e., A12, A15 and A19) were overall nominated as the premiere. Taking leaf-derived calli into account, only l-glutamine-based media in an ascending order of A8, A4, A6, A5, A9 and A3 were introduced as non-dominated alternatives. Such results connote that l-glutamine-based feeding appears to generate more significant results either for continuous calli growth or taxanes production. In contrast, regarding the second explant, stem, both amino acid supplies had fairly equal worth. Our findings, overall, demonstrate promising applications of the proposed AHP method regarding accurate selection of the best callus maintenance cultures of T. baccata for production of different taxanes including paclitaxel, Baccatin III and 10-deacetylbaccatin III. Similarly, this statistical approach could be also applicable for other crops, for instance, for accurate selection of the best callus cultures/media and consequently production improvement of a given plant secondary metabolite/product.

This study determined the concentration of heavy metals (Al, Cr, Cu, and Zn) in water and sediments at nine sites in the Hara biosphere reserve of southern Iran during the summer and winter 2010. Determination of Al, Cr, Cu, and Zn in water was carried out by graphite furnace atomic absorption spectrometer (Shimadzu, AA 610s) and in sediment by flame atomic absorption spectrometer (Perkin Elmer, AA3030). Results showed that the heavy metal concentrations in the water samples decreased in the sequence of Zn > Al > Cu > Cr, while in sediment samples were Cr > Zn > Cu > Al. Data analysis indicated that with the exception of Al, there was a Pearson’s correlation coefficient between pH and Cu, Zn, and Cr at α = 0.01, 0.05, and 0.001 in sediment (in winter), respectively. There were also significant differences between heavy metals of Cr, Cu, and Zn during the two seasons ( p