Magnetorheology of hybrid colloids obtained by spin-coating and classical rheometry

Hybrid colloids composed of micron-sized ferromagnetic (carbonyl iron) and diamagnetic (silica) particles suspended in cyclohexanone, behave as, non-Newtonian, magnetorheological fluids. We measure and compare the magnetic field-dependent viscosity of hybrid diluted colloids using spin-coating and conventional magnetorheometry. We extend a previously developed model for simple colloids to this kind of hybrid colloids. As in the previous model, the viscosity of the colloidal suspension under applied fields can be derived from the surface coverage of the dry spin-coated deposits for each type of particles, and from the viscosity of the colloid at zero field. Also, our results allow us to obtain the evaporation rate of the solvent as a function of the rotation speed. Finally, we also measure the viscosity of the same suspension with a torsional parallel plate magnetorheometer under uniaxial DC magnetic fields aligned in the velocity gradient direction of a steady shearing flow. The experimental results under different conditions and the effect of each component on the magnetorheological properties of the resulting colloid are discussed. Standard spin-coating technique can be used both to characterize smart materials - complex fluids as well as to fabricate films with arbitrary solvents by tuning their viscosity by means of external fields

Ternary solid-ferrofluid-liquid magnetorheological fluids

A new kind of magnetorheological fluid is proposed that exhibits both enhanced magnetorheological effect and kinetic stability against sedimentation. It includes the presence of small amounts of an emulsified aqueous ferrofluid as a third phase in a conventional oil-based magnetorheological fluid prepared by the dispersion of carbonyl iron microparticles.This work was supported by MINECO MAT 2016-78778-R and PCIN-2015-051 projects (Spain), the European Regional Development Fund (ERDF) and by the Junta de Andalucía P11-FQM-7074 project (Spain). J J Yang acknowledges the Chinese State Scholarship Fund. J R Morillas acknowledges the FPU14/01576 fellowship

Does designation as a UNESCO World Heritage Site influence tourist evaluation of a local destination?

The purpose of this study is to explore whether the UNESCO World Heritage Site (WHS) designation affects tourists’ evaluation of the local destination hosting the site, building on a large sample of about 0.8 million tourists who visited Italy over the period 1997-2015. We find that the inscription onto the UNESCO World Heritage List exerts surprisingly a negative effect on the overall evaluation of the destination and also on the evaluation of its artistic assets though the magnitude of the latter is lower. The effect is heterogeneous across visitors, depending on evaluation levels, as well as origin/destinations and demographics. Nonetheless, the presence of multiple WHSs in the same destination tends to increase evaluation suggesting that destination stakeholders with previous experience in dealing with WHS designations are better equipped to manage the complicated relationship between tourism and preservation. Managerial and policy-making implications are discussed

Contovir - A new adjuvant therapy in recurrent respiratory papillomatosis: A case study

Background: Contovir is a mixture of herbal extracts (Tanacetum vulgare, Rossa canina, Urtica dioica) that is supplemented with selenium. Objectives: This study aimed to add Contovir to the classic treatment of recurrent respiratory papillomatosis (RRP) in order to decrease the severity and extent of the disease, elongate the surgical intervals and improve the sense of patient well-being. Furthermore, we had to adjust the prescribed drug dosage, since there were no previous findings available. Patients and Methods: This is a case study of RRP patients treated with Contovir as an adjuvant to the classic treatment, from March 2011 to February 2013, at an academic tertiary hospital (Rasoul-e-Akram hospital). All patients underwent surgical removal of papilloma and then were prescribed Contovir. Disease severity was quantified based on Derkay�s staging system. Results: Eight patients were enrolled in this study. The extent and severity of the disease improved in six cases. One had no response, and the severity of disease increased in one patient. Patients with supraglottic lesions had better responses to Contovir adjuvant therapy. No immediate or long-term side effects were reported. Conclusions: Although Contovir has been found to be an advantageous adjuvant for RRP treatment, further studies are called for to verify these findings. © 2016, Iranian Red Crescent Medical Journal

A comparative study on the equine and camelid antivenoms upon cardiovascular changes induced with Hemiscorpius lepturus venom in rats

Objective(s): In this study, the neutralizing abilities of the equine and the recently introduced camelid antivenoms on the hemodynamic parameters (inotropism, chronotropism, and arrhythmogenicity) were assessed following envenomation by Hemiscorpius lepturus venom in rats. Materials and Methods: At first, the electrophoretic profiles of both products were obtained by using the SDS-PAGE method (12.5%) and stained with Coomassie blue and silver nitrate. Secondly, different doses of the camelid antivenom (10, 50, and 100 μl) were given intravenously in 10 min before venom injection (400 μg/rat). The neutralizing potencies of camelid and equine antivenoms were measured by preincubation (100 μl) with H. lepturus venom for 30 min at room temperature. Finally, equal amounts of the antivenoms were injected intravenously to observe the hemodynamic changes. Results: Based on the electrophoretic profile, it was evident that undesired proteins significantly decreased in equine antivenom, owing to impurities. Pretreatment with the camelid antivenom (100 μl), neutralized the elevation of the mean arterial pressure evoked with scorpion venom injection (88.15±4.56 versus 10.2±1.23 percent at the 8th min). The Incubation of the venom and the camelid antivenom counteracted the hemodynamic changes, but the equine product had no effect. The intravascular injection of the equine antivenom transiently increased the mean arterial pressure as compared to the control (108.67±8.63 mmHg versus 52.67±1.93 mmHg at the 10th min). Conclusion: The most obvious finding emerging from this study was that the camelid antivenom neutralized the hemodynamic changes in rats significantly, but in comparison, the equine antivenom had just a minor ability

Contovir - A new adjuvant therapy in recurrent respiratory papillomatosis: A case study

Background: Contovir is a mixture of herbal extracts (Tanacetum vulgare, Rossa canina, Urtica dioica) that is supplemented with selenium. Objectives: This study aimed to add Contovir to the classic treatment of recurrent respiratory papillomatosis (RRP) in order to decrease the severity and extent of the disease, elongate the surgical intervals and improve the sense of patient well-being. Furthermore, we had to adjust the prescribed drug dosage, since there were no previous findings available. Patients and Methods: This is a case study of RRP patients treated with Contovir as an adjuvant to the classic treatment, from March 2011 to February 2013, at an academic tertiary hospital (Rasoul-e-Akram hospital). All patients underwent surgical removal of papilloma and then were prescribed Contovir. Disease severity was quantified based on Derkay�s staging system. Results: Eight patients were enrolled in this study. The extent and severity of the disease improved in six cases. One had no response, and the severity of disease increased in one patient. Patients with supraglottic lesions had better responses to Contovir adjuvant therapy. No immediate or long-term side effects were reported. Conclusions: Although Contovir has been found to be an advantageous adjuvant for RRP treatment, further studies are called for to verify these findings. © 2016, Iranian Red Crescent Medical Journal