70 research outputs found
Generalized Analysis of Elastic Wave Dispersion Asymmetries in Moving Periodic Media
This work presents a generalized physical interpretation of unconventional
dispersion asymmetries associated moving elastic solids. By shifting the notion
from systems with time-variant material fields to physically traveling
materials, the newly adopted paradigm provides an eloquent take on the
dispersion problem and, in the process, highlights discrepancies between both
schemes. Equations governing the motion of an elastic rod with a prescribed
moving velocity observed from a stationary reference frame are used to predict
propagation patterns and asymmetries in wave velocities induced as a result of
the induced linear momentum bias. Three distinct scenarios corresponding to a
moving rod with a constant modulus, a spatially varying one, and one that
varies in space and time are presented. These cases are utilized to extract and
interpret correlations pertaining to directional velocities, dispersion
patterns, as well as nature of band gaps between moving periodic media and
their stationary counterparts with time-traveling material properties. A linear
vertical shear transformation is derived and utilized to thoroughly neutralize
the effect of the moving velocity on the resultant dispersion characteristics.
Finally, dispersion contours associated with the transient response of a finite
moving medium are used to validate the entirety of the presented framework
The role of BK potassium channels in analgesia produced by alpha-2 adrenergic receptors
BACKGROUND AND OBJECTIVE: Millions of people suffer from pain worldwide, and annually, great economic costs are imposed on societies for pain relief. Analgesics such as alpha-2 adrenergic receptor agonists, which have low risk of complications, can be effective in assuaging pain and reducing costs. According to former studies, potassium channels play an important role in the analgesic mechanism of these receptors. This study aimed to determine the role of BK potassium channels in analgesia induced by alpha-2 adrenergic receptors. METHODS: This study was performed on 56 male Wistar rats weighing 250-300 g that were divided into seven groups of eight rats. We administered 0. 7 mg/kg intraperitoneal (IP) injection of clonidine, 1 mg/kg IP injection of yohimbine, and 5 mg/kg intracerebroventricular (ICV) injection of yohimbine. Iberiotoxin at a dose of 100 nm was also injected ICV. Normal saline and DMSO were applied as solvents. Pain severity was evaluated using formalin test at a concentration of 2%. FINDINGS: The chronic pain induced by formalin injection was relieved by IP injection of 0. 7 mg/kg clonidine. Moreover, 5 μg/kg and 1 μg/kg ICV administration of yohimbine with mean chronic pain scores of 2. 29±0. 13 and 2. 09±0. 07, respectively, could significantly inhibit analgesic effect of clonidine with mean chronic pain score of 1. 55±0. 14 (p<0. 001). ICV injection of iberiotoxin with mean chronic pain score of 2. 33±0. 16 at a dose of 100 nm significantly diminished analgesic effects of clonidine. CONCLUSION: Alpha-2 adrenergic receptor agonists could induce analgesia in the animals, and the antagonist of this receptor inhibited the analgesic effect of agonists of these receptors. BK channel inhibition prevented analgesic effect of adrenergic receptor agonists, as well. © 2016, Babol University of Medical Sciences. All rights reserved
Phenoloxidase activity acts as a mosquito innate immune response against infection with semliki forest virus
Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses
Comparable endocrine and neuromuscular adaptations to variable vs. constant gravity-dependent resistance training among young women.
BACKGROUND:Variable resistance has been shown to induce greater total work and muscle activation when compared to constant resistance. However, little is known regarding the effects of chronic exposure to variable resistance training in comparison with constant resistance training. The aim of the present study was therefore to examine the effects of chain-loaded variable and constant gravity-dependent resistance training on resting hormonal and neuromuscular adaptations. METHODS:Young women were randomly assigned to variable resistance training (VRT; n = 12; age, 23.75 ± 3.64 years; and BMI, 26.80 ± 4.21 kg m-2), constant resistance training (CRT; n = 12; age, 23.58 ± 3.84 years; BMI, 25.25 ± 3.84 kg m-2), or control (Con; n = 12; age, 23.50 ± 2.93 years; BMI, 27.12 ± 12 kg m-2) groups. CRT performed 8-week total-body free-weight training three times per week with moderate-to-high intensity (65-80% 1RM; periodized). VRT was the same as CRT but included variable resistance via chains (15% of total load). Resting serum samples were taken before and after the 8-week intervention for GH, IGF-1, cortisol, myostatin, and follistatin analyses. RESULTS:Both VRT and CRT groups displayed moderate-to-large significant increases in GH (197.1%; ES = 0.78 vs. 229.9%; ES = 1.55), IGF-1 (82.3%; ES = 1.87 vs. 66%; ES = 1.66), and follistatin (58.8%; ES = 0.80 vs. 49.15%; ES = 0.80) and decreases in cortisol (- 19.9%; ES = - 1.34 vs. - 17.1%; ES = - 1.05) and myostatin (- 26.9%; ES = - 0.78 vs. - 23.2%; ES = - 0.82). Also, VRT and CRT resulted in large significant increases in bench press (30.54%; ES = 1.45 vs. 25.08%; ES = 1.12) and squat (30.63%; ES = 1.28 vs. 24.81%; ES = 1.21) strength, with no differences between groups. CONCLUSIONS:Implementing chain-loaded VRT into a periodized resistance training program can be an effective alternative to constant loading during free-weight RT among untrained young women
Factors influencing BIM adoption in emerging markets—the case of India
This paper studies the adoption of Building Information Modelling (BIM) in emerging markets. The factors responsible for the adoption of BIM are studied in the context of Indian architectural firms. The mechanisms of diffusion of BIM are analysed through a questionnaire survey based on the Technology–Organization–Environment (TOE) framework which broadly categorises the influencing factors along these three dimensions. Data were collected through a web-based questionnaire survey. The 184 valid responses were analysed using descriptive statistics. The study found that full potential of BIM has been explored but not realised by many in the Indian construction sector. Findings of the study are analysed and compared with other emerging and developed markets. Based on the survey results, recommendations for increasing the BIM adoption are provided. Further studies and learnings from mature markets can help Indian construction sector develop effective BIM implementation strategies
Object-Based Building Extraction from High Resolution Satellite Imagery
Automatic building extraction from high resolution satellite imagery is considered as an important field of research in remote sensing and machine vision. Many algorithms for extraction of buildings from satellite images have been presented so far. These algorithms mainly have considered radiometric, geometric, edge detection and shadow criteria approaches to perform the building extraction. In this paper, we propose a novel object based approach for automatic and robust detection and extraction of building in high spatial resolution images. To achieve this goal, we use stable and variable features together. Stable features are derived from inherent characteristics of building phenomenon and variable features are extracted using SEparability and THresholds analysis tool. The proposed method has been applied on a QuickBird imagery of an urban area in Isfahan city and visual validation demonstrates that the proposed method provides promising results
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