Role of Osmolytes in Amyloidosis

Osmolytes are naturally occurring small organic molecules present in all kingdoms of life. These organic molecules are accumulated by living systems to circumvent stress conditions. A number of human diseases have been grouped under the protein-misfolding diseases. These entire diseases share the same hallmarks of the presence of cellular inclusions and plaques that are deposited in the cells and tissues affected by the disease. These misfolded forms of protein are responsible for initiating toxic cascades in the cell, causing vesicle dystrafficking, synaptic and cell organelle dysfunction, and ultimately cell death. Published results suggest that cells regulate many biological processes such as protein folding, protein disaggregation, and protein-protein interactions via accumulation of specific osmolytes. Since, as of now, complete cure for these protein-misfolding disorders does not exist; therefore, it becomes increasingly important to review the recent works on this aspect to develop strategies for therapeutics. It has been shown that certain osmolytes can prevent the proteins from misfolding. Thus, osmolytes can be utilized as therapeutics for such diseases. In this review article, we discuss the role of naturally occurring osmolytes in various forms of amyloidosis associated with human diseases

Transverse susceptibility study of the effect of varying dipolar interactions on anisotropy peaks in a three-dimensional assembly of soft ferrite nanoparticles

Collective magnetization dynamics in nanoparticle assemblies is of current interest as it forms the basis of high density storage media. It is important to understand how interparticle interactions in a three-dimensional (3D) arrangement of superparamagnetic nanoparticles would affect the overall effective magnetic anisotropy of the system. We have studied the influence of varying strengths of dipolar interaction on the static and dynamic magnetic properties of surfactant-coated monodispersed manganese zinc ferrite nanoparticles using reversible transverse susceptibility. We track the evolution of the anisotropy peaks with varying magnetic field, temperature, and interaction strength. The blocking temperature shows an increase from 28 to 32 K and the coercive field (at 10 K) shows an increase from 144 to 192 Oe as the system changes from the case of weakly interacting to strongly interacting 3D assembly of the particles

Culturally-Relevant Persuasive Technology

Persuasive technology (PT) has been defined by B. J. Fogg as "any interactive computing system designed to change peoples attitudes or behaviors". The kinds of attitudes people hold, and the behaviours they exhibit, are influenced by culture, so cultural beliefs play a large role in persuasion. The cross-cultural psychology literature has demonstrated the power of culture on attitude change. To date, however, there has been limited persuasive technology research outside of countries characterised as having individualist culture, where individualism describes cultures in which society members have a primarily individual identity. Little research has explicitly investigated the relationship between persuasive technology and culture. In this thesis, we investigated the hypothesis that persuasive technology is more effective when it reflects the culture of its intended target audience. Firstly, we established a set of effective, culturally-relevant persuasive technology strategies, almost all of which are targeted at use in tools for collectivist audiences. The strategies are based on a combination of findings from the cross-cultural psychology literature focused on the dimensions of individualism and collectivism, an analysis of existing PT strategies, and qualitative insights. Secondly, we developed a culturally-relevant PT prototype based on several of our strategies, in the form of two versions of a game titled Smoke? about smoking cessation. One version of Smoke? was designed to be more persuasive for a NZ European player audience, while the other was designed to be more persuasive for a Maori player audience. We conducted focus groups with potential players, the insights of which guided how we applied several of our culturally-relevant PT strategies in the design of the two game versions. Finally, we evaluated both game versions on individualist, and collectivist test players, using both quantitative and qualitative methods. The results of our evaluation support our hypothesis. Not only did both sets of players engage with, and use the culturally-relevant interface elements of the game designed for their culture, they also demonstrated that the culturally-relevant game versions had increased their anti-smoking beliefs

Human Blood Vessel–Derived Endothelial Progenitors for Endothelialization of Small Diameter Vascular Prosthesis

BACKGROUND:Coronary bypass graft failure as a result of acute thrombosis and intimal hyperplasia has been the major challenge in surgical procedures involving small-diameter vascular prosthesis. Coating synthetic grafts with patients' own endothelial cells has been suggested to improve the patency rate and overall success of bypass surgeries. METHODOLOGY/PRINCIPAL FINDINGS:We isolated endothelial progenitor cells (EPCs) from leftover pieces of human saphenous vein/mammary artery. We demonstrate that EPCs can be expanded to generate millions of cells under low-density culture conditions. Exposure to high-density conditions induces differentiation to endothelial cell phenotype. EPC-derived endothelial cells show expression of CD144high, CD31, and vWF. We then assessed the ability of differentiated endothelial cells to adhere and grow on small diameter expanded polytetrafluoroethylene (ePTFE) tubings. Since ePTFE tubings are highly hydrophobic, we optimized protocols to introduce hydrophilic groups on luminal surface of ePTFE tubings. We demonstrate here a stepwise protocol that involves introduction of hydrophilic moieties and coating with defined ECM components that support adhesion of endothelial cells, but not of blood platelets. CONCLUSION/SIGNIFICANCE:Our data confirms that endothelial progenitors obtained from adult human blood vessels can be expanded in vitro under xenoprotein-free conditions, for potential use in endothelialization of small diameter ePTFE grafts. These endothelialized grafts may represent a promising treatment strategy for improving the clinical outcome of small-caliber vascular grafts in cardiac bypass surgeries

Coplanar switching of polarization in thin films of vinylidene fluoride oligomers

Switching characteristics of vinylidene fluoride oligomer thin films with molecular chains aligned normal to the substrate and exhibiting a preferential in-plane polarization have been investigated using coplanar geometry of inter-digital electrodes via high-resolution piezoresponse force microscopy. It has been shown that in-plane switching proceeds via non-180 rotation of dipoles mediated by non-stochastic nucleation, expansion, and coalescence of domains. Asgrown multidomain configuration is found to be strongly pinned aided by charged domain walls, and the electrically induced (in-plane) mono-domain states relax to the as-grown state. The observed coercive field (approximately 0.6 MV/m) is two to three orders of magnitude smaller than that for the oligomer films with out-of-plane polarization. It is suggested that the low steric hindrance to the rotation of molecular dipoles gives rise to the observed low coercive field

Temperature and Magnetic Field-Assisted Switching of Magnetization and Observation of Exchange Bias in YbCrO₃ Nanocrystals

In this paper, we demonstrate an interesting feature in YbCrO₃ (YCO) nanocrystals, in which the material shows temperature and external magnetic field-assisted switching (a complete sign reversal) of zero field cooled magnetization (<i>M</i>_ZFC) and observation of exchange bias (EB) as a result of competing spin interaction at low temperature. This feature can be applied in nonvolatile memories, where, simply by changing the magnitude of the <i>H</i>_ext and <i>T</i>, the polarity of the magnetization can be switched between negative and positive. We also observed negative magnetization in YCO. Our results showed that, below its Nèel temperature (<i>T</i>_N ≈ 119 K), the <i>M</i>_ZFC crosses over to negative sign for <i>H</i> < 1000 Oe. At 60 K, YCO showed a significant negative <i>M</i>_ZFC ≈ −0.05 emu/g (at 100 Oe) due to the competing effects of Yb^<i>3+</i>, Cr³⁺ spins, thermal activation energy, and <i>H</i>_ext. At further lower temperatures, the <i>M</i>_ZFC showed a crossover to positive values, and the crossover temperature showed the dependence on <i>H</i>_ext (∼19 K for 100 Oe curve). The YCO also showed <i>H</i>_ext and <i>T</i>-dependent <i>H</i>_EB, which changed its sign with <i>T</i>. The observed <i>T</i>-dependent sign reversal in the EB was closely associated with the sign reversal of <i>M</i>_ZFC. The symmetric shift in field-cooled isothermal hysteresis curves confirmed that the observed EB was not due to the unsaturated minor loop. The training cycle further confirmed that the <i>H</i>_EB value decreased to ∼2% of the initial value of observed EB, which was very small compared to the observed <i>H</i>_EB in YCO, which indicated stable spin configuration at the locally formed ferromagnetic/antiferromagnetic interface