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Electronic properties of SnO2-based ceramics with double function of varistor and humidity sensor
This is the post-print version of the article. The official published version can be obtained from the link below - Copyright @ 2010 AD-Tech.Tin dioxide based varistor ceramics SnO2-Co3O4-Nb2O5-Cr2O3-xCuO (x=0; 0.05; 0.1 and 0.5) were made and their electrical properties were studied. The highest nonlinearity coefficient and electric field (at current density 10-3 A cm-2) were obtained for 0.1 mol.% CuO addition. It was observed that low-field electrical conductivity is increased with relative humidity, therefore, materials obtained exhibit double function of varistor and humidity sensor. The highest humidity sensitivity coefficient is found for SnO2-Co3O4-Nb2O5-Cr2O3 ceramics (without CuO). Observed varistor and humidity-sensitive properties are explained in the frames of grain-boundary double Schottky barrier concept as a decrease of the barrier height with electric field or relative humidity. Using suggested simple theory and data obtained on isothermal capacitance relaxation, the energy of the grain-boundary monoenergetic trapping states were estimated. These values are less than found for activation energy of electrical conduction (as a measure of the barrier height). These observations confirm the barrier concept.This work is funded by the Royal Society, United Kingdom (2007R1/R26999)
A review : a comprehensive review of soft and rigid wearable rehabilitation and assistive devices with a focus on the shoulder joint
The importance of the human upper limb role in performing daily life and personal activities is significant. Improper functioning
of this organ due to neurological disorders or surgeries can greatly affect the daily activities performed by patients. This paper
aims to comprehensively review soft and rigid wearable robotic devices provided for rehabilitation and assistance focusing on the
shoulder joint. In the last two decades, many devices have been proposed in this regard, however, there have been a few groups
whose devices have had effective therapeutic capability with acceptable clinical evidence. Also, there were not many portable,
lightweight and user-friendly devices. Therefore, this comprehensive study could pave the way for achieving optimal future
devices, given the growing need for these devices. According to the results, the most commonly used plan was Exoskeleton, the
most commonly used actuators were electrical, and most devices were considered to be stationary and rigid. By doing these
studies, the advantages and disadvantages of each method are also presented. The presented devices each have a new idea and
attitude in a specific field to solve the problems of movement disorders and rehabilitation, which were in the form of prototypes,
initial clinical studies and sometimes comprehensive clinical and commercial studies. These plans need more comprehensive
clinical trials to become a complete and efficient plan. This article could be used by researchers to identify and evaluate the
important features and strengths and weaknesses of the plans to lead to the presentation of more optimal plans in the future
Role of toll-like receptors and their ligands in adipocyte secretion
Background: Adipose tissue is one of the main sites of energy homeostasis that regulates whole body metabolism with the help of adipokines. Disruption in its proper functioning results in adipose tissue remodeling (primarily hypertrophy and hyperplasia) which directly influences the secretion of said adipokines. Obesity characterized as chronic low-grade inflammation of the adipose tissue is one such condition that has far reaching effects on whole body metabolism. Inflammation in turn results in immune cells infiltrating into the tissue and further promoting adipocyte dysfunction.
Purpose: In our study we explored this adipose tissue-innate immunity axis by differentiating adipose tissue derived stem cells (ADSCs) into white and beige adipocytes. We further stimulated our cultures with lipopolysaccharide (LPS), flagellin, or meteorin-like, glial cell differentiation regulator (METRNL) to trigger an inflammatory response. We then evaluated Toll-like receptor (TLR) mRNA expression and secretion of interleukin (IL-6), interleukin-8 (IL-8), brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF) in these cultures.
Results: We found that TLR2 is the highest expressed receptor in adipocytes. Further, LPS and METRNL are strong activators of TLR2 in white and beigeBMP7(-) adipocytes. TLR4 was not significantly expressed in any of our cultures despite LPS stimulation. TLR9 expression is upregulated in ADSCs upon LPS and METRNL stimulation. IL-6 and IL-8 secretion is increased upon LPS stimulation in white adipocytes. METRNL activates both IL-6 and IL-8 expression in adipocyte cultures. Lastly, BDNF and NGF is secreted by all adipocyte cultures with beigeBMP7(-) and beigeBMP7(+) secreting slightly higher amounts in comparison to white adipocytes.
Conclusion: ADSCs and adipocytes alike are capable of expressing TLRs, but white adipocytes remain the highest expressing in both control and stimulated cultures. TLR2 is highly expressed in white and beige adipocytes whereas TLR4 showed no significant expression. LPS and METRNL trigger IL-6 and IL-8 secretion in adipocytes. Products of white adipocyte “browning” are capable of secreting higher amounts of BDNF and NGF in comparison to white adipocytes