Edge preservation of impulse noise filtered images by improved anisotropic diffusion

This paper provides a robust scheme for random valued impulsive noise reduction along with edge preservation by anisotropic diffusion with improved diffusivity. The defective impulse noisy pixels are detected by Laplacian based second order pixel difference operation where these defective pixels are replaced by appropriate values with regard of the gray level of their four directional neighbors. This de-noised image undergoes the diffusion operation where diffusion coefficient function is modified to make it adaptive by incorporating local gray level variance information. The proposed modified diffusion scheme effectively restore the edges and fine details destroyed during impulse noise reduction process. The effect of proposed diffusion scheme has been studied on various images and the results are compared with some existing diffusion methods which are independently used for impulse noise reduction and edge preservation. The results shows that the prior removal of impulsive noise before the application of diffusion process is advantageous over the direct application of diffusion for removing the impulsive noise. In addition, the results of the proposed diffusion scheme are compared with some of the median filter based methods which are effectively used for impulse noise reduction without caring of edge preservation. The proposed diffusion scheme sufficiently preserves the edges without boosting of impulsive noise components on images corrupted up to 50 % of the impulsive noise density.     

Improved occupancy grid mapping in specular environment

This paper addresses the improved method for sonar sensor modeling which reduces the specular reflection uncertainty in the occupancy grid. Such uncertainty reduction is often required in the occupancy grid mapping where the false sensory information can lead to poor performance. Here, a novel algorithm is proposed which is capable of discarding the unreliable sonar sensor information generated due to specular reflection. Further, the inconsistency estimation in sonar measurement has been evaluated and eliminated by fuzzy rules based model. To achieve the grid map with improved accuracy, the sonar information is further updated by using a Bayesian approach. In this paper the approach is experimented for the office environment and the model is used for grid mapping. The experimental results show 6.6% improvement in the global grid map and it is also found that the proposed approach is consuming nearly 16.5% less computation time as compared to the conventional approach of occupancy grid mapping for the indoor environments.     

Signal transduction mechanisms involved in angiotensin-(1-7)-stimulated arachidonic acid release and prostanoid synthesis in rabbit aortic smooth muscle cells

This study investigated the signal transduction mechanisms of angiotensin-(1-7) [Ang-(1-7)]- and Ang II-stimulated arachidonic acid (AA) release for prostaglandin (PG) production in rabbit aortic vascular smooth muscle cells. Ang II and Ang-(1-7) enhanced AA release in cells prelabeled with [3H]AA. However, 6-keto-PGF1 alpha synthesis produced by Ang II was much less than that caused by Ang-(1-7). In the presence of the lipoxygenase inhibitor baicalein, Ang II enhanced production of 6-keto-PGF1 alpha to a greater degree than Ang-(1-7). Angiotensin type (AT)1 receptor antagonist DUP-753 inhibited only Ang II-induced [3H]AA release, whereas the AT2 receptor antagonist PD-123319 inhibited both Ang II- and Ang-(1-7)-induced [3H]AA release. Ang-(1-7), receptor antagonist D-Ala7-Ang-(1-7) inhibited the effect of Ang-(1-7), but not of Ang II. In cells transiently transfected with cytosolic phospholipase A2 (cPLA2), mitogen-activated protein (MAP) kinase or Ca(++)-/cal-modulin-dependent protein (CAM) kinase II antisense oligonucleotides, Ang-(1-7)- and Ang II-induced [3H]AA release was attenuated. The CaM kinase II inhibitor KN-93 and the MAP kinase kinase inhibitor PD-98059 attenuated both Ang-(1-7)- and Ang II-induced cPLA2 activity and [3H]AA release. Ang-(1-7) and Ang II also increased CaM kinase II and MAP kinase activities. Although KN-93 attenuated MAP kinase activity, PD-98059 did not affect CaM kinase II activity. Both Ang II and Ang-(1-7) caused translocation of cytosolic PLA2 to the nuclear envelope. These data show that Ang-(1-7) and Ang II stimulate AA release and prostacyclin synthesis via activation of distinct types of AT receptors. Both peptides appear to stimulate CaM kinase II, which in turn, via MAP kinase activation, enhances cPLA2 activity and release of AA for PG synthesis.     

Nanofiltration Membrane Process for the Removal of Arsenic from Drinking Water

The removal of arsenic from drinking water by nanofiltration membranes was investigated. Experiments were conducted with tap water to which arsenate and arsenite were added. Two types of nanofiltration membranes, i.e., NF‐90 and NF‐200, have been tested. The effect of various operating conditions, e.g., applied pressure, feed concentration, pH and temperature, were also investigated. The pH and arsenic concentration in the feed and the operating temperature are found to be decisive factors in determining the arsenic concentration remaining in the permeate. The level of removal of As(V) was higher than 98 % for both membranes, but that of As(III) was much lower. It can be concluded that by controlling the operating parameters, source water containing As(V) may be recovered as drinking water to EPA maximum contaminant level quality standards, but that water containing As(III) must undergo a pre‐oxidation treatment before passing through the nanofiltration membrane in order to maintain drinking water quality.     

Biallelic Variants in EPHA2 Identified in Three Large Inbred Families with Early-Onset Cataract

Hereditary congenital cataract (HCC) is clinically and genetically heterogeneous. We investigated HCC that segregates in three inbred families (LUCC03, LUCC16, and LUCC24). Ophthalmological examinations revealed cataracts with variability related to the age of onset segregating in a recessive manner in these families. Exome sequencing of probands identified a novel homozygous c.2710delG;p.(Val904Cysfs*36) EPHA2 variant in LUCC03 and a known homozygous c.2353G>A;p.(Ala785Thr) EPHA2 variant in the other two recessive families. EPHA2 encodes a transmembrane tyrosine kinase receptor, which is primarily involved in membrane-transport, cell-cell adhesion, and repulsion signaling processes. Computational structural modeling predicts that substitution of a threonine for an alanine p.(Ala785Thr) results in the formation of three new hydrogen bonds with the neighboring residues, which causes misfolding of EPHA2 in both scenarios. Insights from our study will facilitate counseling regarding the molecular and phenotypic landscape of EPHA2-related HCC.     

Changes in the wettability of polymer electrolyte fuel cells components during cationic contamination and mitigation

Foreign cations are shown to cause mass transport losses, in particular due to wettability changes in the micro-porous layers (MPL) and the carbon paper substrate, and have a major impact on the durability and the performance of polymer electrolyte fuel cells. We studied the effects of cationic impurities on fuel cell system performance, especially on the water management by employing in-situ and ex-situ contamination methods. Changes in the wettability of the carbon paper surface following the in-situ contamination injection were quantified using the Wilhelmy plate method. The CaSO₄ precipitation on the macro-pores of the carbon paper substrate after the contamination injection causes a higher wettability leading to increased flooding of the carbon paper substrate and consequent mass transport losses. An ex-situ cleaning with an acid solution is shown to be very effective in removing the salt deposits of the carbon paper substrate. During the mitigation, the highly hydrophobic MPL acts as a barrier to the transport of the recovery solution into the membrane-electrode assembly (MEA), therefore isopropanol (IPA) was added to both the contaminant solution and the recovery solution to increase the wettability of the MPL. Wetting force measurements confirm that the added IPA can alter the wettability of the MPL and can render it fully hydrophilic, enabling the transport of the recovery solution into the MEA.     

Flavonoids as Antidiabetic and Anti-Inflammatory Agents: A Review on Structural Activity Relationship-Based Studies and Meta-Analysis

Flavonoids are a group of naturally occurring polyphenolic secondary metabolites which have been reported to demonstrate a wide range of pharmacological properties, most importantly, antidiabetic and anti-inflammatory effects. The relationship between hyperglycaemia and inflammation and vascular complications in diabetes is now well established. Flavonoids possessing antidiabetic properties may alleviate inflammation by reducing hyperglycaemia through different mechanisms of action. It has been suggested that the flavonoids’ biochemical properties are structure-dependent; however, they are yet to be thoroughly grasped. Hence, the main aim of this review is to understand the antidiabetic and anti-inflammatory properties of various structurally diverse flavonoids and to identify key positions responsible for the effects, their correlation, and the effect of different substitutions on both antidiabetic and anti-inflammatory properties. The general requirement of flavonoids for exerting both anti-inflammatory and antidiabetic effects is found to be the presence of a C2–C3 double bond (C-ring) and hydroxyl groups at the C3’, C4’, C5, and C7 positions of both rings A and B of a flavonoid skeleton. Furthermore, it has been demonstrated that substitution at the C3 position of a C-ring decreases the anti-inflammatory action of flavonoids while enhancing their antidiabetic activity. Correlation is discussed at length to support flavonoids possessing essential pharmacophores to demonstrate equipotent effects. The consideration of these structural features may play an important role in synthesizing better flavonoid-based drugs possessing dual antidiabetic and anti-inflammatory effects. A meta-analysis further established the role of flavonoids as antidiabetic and anti-inflammatory agents.     

Wear Measurement and Assessment of Explanted Cross-Linked PE Acetabular Cups Using a CMM

Wear has been considered the main limiting factor in the longevity of hip replacements. Wear analysis is thus essential for determining wear-related failure mechanisms and prediction of wear, which will consequently enable biomedical engineers to improve the design, material, and service life of the bearing components. This article presents wear measurement and assessment of the explanted conventional cross-linked polyethylene (XPE) and second-generation highly cross-linked polyethylene cups (X3) using a coordinate measuring machine (CMM). An expanded uncertainty analysis was performed to assess the performance of wear measurement. Wear measurement using the CMM method was validated with the gravimetric technique. The normalized error between volumetric wear measurement of the CMM method and that of the gravimetric technique was estimated to be always less than 1, suggesting that the CMM method applied to explanted hip wear measurements under the specific conditions was accurate and reliable. The approach to CMM measurement with uncertainty analysis was shown not only to locate 3D wear scar and wear direction but also to accurately quantify linear and volumetric wear with a maximum volumetric uncertainty of ±3.15 mm³ (95% confidence level). It is shown that identifying the key uncertainty components involved in the measurement process including validation, which contributes to an overall expanded uncertainty budget, is crucial to improve the confidence and the reliability of hip wear measurement results using a CMM.