Applications of Casimir forces:Nanoscale actuation and adhesion

Here, we discuss possible applications of the Casimir forces in micro- and nanosystems. The main part of this paper is devoted to actuation with quantum fluctuations and to the relative contribution of van der Waals and Casimir interactions to adhesion. Switching between the amorphous and crystalline states of phase change materials could generate force contrast sufficient for actuation, though for practical applications, the influence of protective capping layers and volume compression have to be better understood. Resilience against the pull-in instability is also a critical point defined by the material choice, dissipation in the system, and roughness of the surfaces. The adhesion induced by the Casimir forces is omnipresent, and it can play a pivotal role in unwanted stiction demanding deeper understanding. The open problems are the distance upon contact and the relative area of the real contact since both of them control the adhesion. An experiment designed to answer these questions is briefly discussed

Evaluation of self-medication prevalence, diagnosis and prescription in migraine in Kerman, Iran

Objective: To investigate different diagnosis aspects, prescribed drugs and self-medications of migraine in Iran. Methods: We selected 210 migraineurs from high school and university students in Kerman, Iran over a period of 6 months in 2002 by multistage randomized screening based on the International Headache Society criteria. We classified them into 2 groups on the basis of whether they had consulted a physician or not. We then evaluated the physician prescriptions, and prevalence of self-medications. Results: Only 49 of migraineurs consulted a physician, and only 53 were correctly diagnosed by physicians according to the International Headache Society criteria. Our study shows that 69 of general practitioners diagnoses were wrong. In spite of indications for prophylactic treatment, it was not prescribed in 76 of the patients, and 50 of the general practitioners prescribed it without any indications. Furthermore, 91 of patients used self-medication; Acetaminophen and Codeine were the most common. Conclusion: General practitioners' misdiagnosis and mismanagement of the migraineurs, and easy access to various drugs in Iran, have led to a high rate of self-medication. Self-medication with Codeine, with regard to its side effects, such as increase of secondary headaches and dependency is the major problem. Consequently, medical education systems, physician reevaluating methods, and the concept of self-medication among patients have to be revised

Designing of ECAP parameters based on strain distribution uniformity

AbstractEqual Channel Angular Pressing (ECAP) is currently one of the most popular methods for fabricating Ultra-Fine Grained (UFG) materials. In this work, ECAP process has been performed on commercial pure aluminum up to 8 passes by route A. After verification of FEM work, the influences of four die channel angles, three outer corner angles and pass number up to 8 have been analyzed to investigate strain distribution behavior of ECAPed material. Two methods for quantifying the strain homogeneity namely inhomogeneity index (Ci) and standard deviation (S.D.) are compared. It is shown that Ci is not a good candidate for examining the strain distribution uniformity. Moreover, it is suggested that designing of ECAP die geometry to achieve optimum strain distribution homogeneity is more suitable than the optimum effective strain magnitude. The best strain distribution uniformity in the transverse plane is obtained with Φ=60° and Ψ=15° and for the bulk of the sample, Φ=120° and Ψ=15° or 60°, gives the highest strain dispersal uniformity

Investigation on batch biosorption of lead using Lactobacillius bulgaricus in an aqueous phase system

In this research, the biosorption of lead by Lactobacillus bulgaricus was investigated. The mechanism for the biosorption was similar to ionic exchanger. The media pH, weight of dried biomass and initial lead concentration were investigated at ambient temperature. At highacidic solution (p

Epigenetic Chromatin Silencing: Bistability and Front Propagation

The role of post-translational modification of histones in eukaryotic gene regulation is well recognized. Epigenetic silencing of genes via heritable chromatin modifications plays a major role in cell fate specification in higher organisms. We formulate a coarse-grained model of chromatin silencing in yeast and study the conditions under which the system becomes bistable, allowing for different epigenetic states. We also study the dynamics of the boundary between the two locally stable states of chromatin: silenced and unsilenced. The model could be of use in guiding the discussion on chromatin silencing in general. In the context of silencing in budding yeast, it helps us understand the phenotype of various mutants, some of which may be non-trivial to see without the help of a mathematical model. One such example is a mutation that reduces the rate of background acetylation of particular histone side-chains that competes with the deacetylation by Sir2p. The resulting negative feedback due to a Sir protein depletion effect gives rise to interesting counter-intuitive consequences. Our mathematical analysis brings forth the different dynamical behaviors possible within the same molecular model and guides the formulation of more refined hypotheses that could be addressed experimentally.Comment: 19 pages, 5 figure

Control surface wettability with nanoparticles from phase-change materials

The wetting state of surfaces can be controlled physically from the highly hydrophobic to hydrophilic states using the amorphous-to-crystalline phase transition of Ge2Sb2Te5 (GST) nanoparticles as surfactant. Indeed, contact angle measurements show that by increasing the surface coverage of the amorphous nanoparticles the contact angle increases to high values ∼140°, close to the superhydrophobic limit. However, for crystallized nanoparticle assemblies after thermal annealing, the contact angle decreases down to ∼40° (significantly lower than that of the bare substrate) leading to an increased hydrophilicity. Moreover, the wettability changes are also manifested on the capillary adhesion forces by being stronger for the crystallized GST state

Prevalence, and virulence determination of listeria monocytogenes strains isolated from clinical and non-clinical samples by multiplex polymerase chain reaction

Introduction: This study aimed to determine the prevalence, and virulence factors of Listeria monocytogenes isolated from various samples by multiplex polymerase chain reaction (MPCR). Methods: A total of 617 isolates were obtained and MPCR was employed for detection of the inlA, inlC, and inlJ genes. Results: L. monocytogenes was detected in 46 (7.45) of the 617 specimens. inlA, inlC, and inlJ were detected in 100, 76.26, and 71 isolates, respectively. Conclusions: This study validated MPCR in the analysis and rapid detection of L. monocytogenes. The role of the genes in pathogenesis of the strains can also be affirmed. © 2016, Sociedade Brasileira de Medicina Tropical. All rights reserved

Targeted Reinforcement of Macrophage Reprogramming Toward M2 Polarization by IL-4-Loaded Hyaluronic Acid Particles

Alteration of macrophage polarization from inflammatory (M1) to anti-inflammatory (M2) phenotype can have striking implications for the regeneration of injured tissues, treatment of inflammatory diseases, and relief of autoimmune disorders. Although certain cytokines like interleukin (IL)-4 and IL-13 are capable of inducing M2 macrophage polarization, their therapeutic potential in vivo is suffering from low efficacy due to their instability and poor access to target cells. Here, we report the synthesis of IL-4-loaded hyaluronic acid (HA) particle for the targeted delivery of cytokines through the high affinity of HA to CD44 receptors of macrophages. HA carriers composed of low, middle, and high molecular weight (MW) polymers were synthesized using divinyl sulfone (DVS) cross-linking. The MW of HA had a negligible effect on the physicochemical properties and biocompatibility of the macrophages, but as an indicative of M2 polarization, a significant change in the arginase-1 (Arg-1) activity, TNF-a release, and IL-10 secretion was observed for the HA particles prepared with high MW polymers. Therefore, these particles were loaded with IL-4 for simultaneous macrophage targeting and M1 to M2 reprogramming, evidenced by a remarkable increase in the Arg-1 to iNOS ratio, as well as CD163 and CD206 upregulation in the M1 macrophages, which were initially triggered by lipopolysaccharide and interferon-y.M.-A.S. acknowledges financial support from Academy of Finland (Decision no. 317316), Iran’s National Elites Foundation and Iran Nanotechnology Initiative Council. T.B.-R. acknowledges financial support from the Fundação para a Ciência e a Tecnologia (Grant no. SFRH/BD/110859/2015). Financial support from the FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through the FCT - Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274) is acknowledged. H.A.S. acknowledges financial support from the Sigrid Jusélius Foundation (Decision no. 4704580), the Helsinki Institute of Life Science, and the Academy of Finland (Decision no. 1317042)

High pressure gas flow, storage, and displacement in fractured rock-Experimental setup development and application.

This paper presents the design, development, and application of a laboratory setup for the experimental investigations of gas flow and reactions in a fractured rock. The laboratory facility comprises (i) a high pressure manometric sorption apparatus, where equilibrium and kinetic phenomena of adsorption and desorption can be examined, (ii) a high pressure triaxial core flooding system where the chemical reactive transport properties or processes can be explored, and (iii) an ancillary system including pure and mixed gas supply and analysis units. Underground conditions, in terms of pore pressure, confining pressure, and temperature, can be replicated using the triaxial core flooding system developed for depths up to 2 km. Core flooding experiments can be conducted under a range of gas injection pressures up to 20 MPa and temperatures up to 338 K. Details of the design considerations and the specification for the critical measuring instruments are described. The newly developed laboratory facility has been applied to study the adsorption of N2, CH4, and CO2 relevant to applications in carbon sequestration in coal and enhanced coalbed methane recovery. Under a wide range of pressures, the flow of helium in a core sample was studied and the evolution of absolute permeability at different effective stress conditions has been investigated. A comprehensive set of high resolution data has been produced on anthracite coal samples from the South Wales coalfield, using the developed apparatus. The results of the applications provide improved insight into the high pressure flow and reaction of various gas species in the coal samples from the South Wales coalfield