Multi-Agent Coverage Control with Energy Depletion and Repletion

We develop a hybrid system model to describe the behavior of multiple agents cooperatively solving an optimal coverage problem under energy depletion and repletion constraints. The model captures the controlled switching of agents between coverage (when energy is depleted) and battery charging (when energy is replenished) modes. It guarantees the feasibility of the coverage problem by defining a guard function on each agent's battery level to prevent it from dying on its way to a charging station. The charging station plays the role of a centralized scheduler to solve the contention problem of agents competing for the only charging resource in the mission space. The optimal coverage problem is transformed into a parametric optimization problem to determine an optimal recharging policy. This problem is solved through the use of Infinitesimal Perturbation Analysis (IPA), with simulation results showing that a full recharging policy is optimal

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

Association of fibroblast growth factor (FGF-21) as a screening biomarker for chronic progressive external ophthalmoplesia

Purpose: To investigate whether or not fibroblast growth factor (FGF-21) can be used as a screening biomarker in chronic progressive external ophthalmoplesia (CPEO) patients. Methods: FGF-21 concentration was measured in the serum of 24 patients with CEPO phenotype and 24 control samples by enzyme-linked immunosorbent assay (ELISA) and determined the deletion of mitochondrial genome by multiplex polymerase chain reaction (PCR). Results: FGF-21 concentration in 50% of CPEO patients showed notable differences from that in control subjects. FGF-21 concentration ratio in patient group, 2 disorder control groups (mitochondrial and non-mitochondrial) and normal group, respectively, was 294.87 ± 42.10 (p 50 years age group who show acute symptoms. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. All rights reserved

Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype \u3cem\u3ein vitro\u3c/em\u3e

Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium–alkali– orthophosphates on osteoblastic phenotype expression and compares this behavior to that of ß-tricalcium phosphate (TCP) and bioactive glass 45S5. Test materials were three materials (denominated GB14, GB9, GB9/25) with a crystalline phase Ca2KNa(PO4)2 and with a small amorphous portion containing either magnesium potassium phosphate (GB14) or silica phosphate (GB9 and GB9/25, which also contains Ca2P2O7); and a material with a novel crystalline phase Ca10[K/Na](PO4)7 (material denominated 352i). SaOS-2 human bone cells were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for an array of osteogenic markers. GB9 had the greatest stimulatory effect on osteoblastic proliferation and differentiation, suggesting that this material possesses the highest potency to enhance osteogenesis. GB14 and 352i supported osteoblast differentiation to the same or a higher degree than TCP, whereas, similar to bioactive glass 45S5, GB9/25 displayed a greater stimulatory effect on osteoblastic phenotype expression, indicating that GB9/25 is also an excellent material for promoting osteogenesis

Minimal-memory realization of pearl-necklace encoders of general quantum convolutional codes

Quantum convolutional codes, like their classical counterparts, promise to offer higher error correction performance than block codes of equivalent encoding complexity, and are expected to find important applications in reliable quantum communication where a continuous stream of qubits is transmitted. Grassl and Roetteler devised an algorithm to encode a quantum convolutional code with a "pearl-necklace encoder." Despite their theoretical significance as a neat way of representing quantum convolutional codes, they are not well-suited to practical realization. In fact, there is no straightforward way to implement any given pearl-necklace structure. This paper closes the gap between theoretical representation and practical implementation. In our previous work, we presented an efficient algorithm for finding a minimal-memory realization of a pearl-necklace encoder for Calderbank-Shor-Steane (CSS) convolutional codes. This work extends our previous work and presents an algorithm for turning a pearl-necklace encoder for a general (non-CSS) quantum convolutional code into a realizable quantum convolutional encoder. We show that a minimal-memory realization depends on the commutativity relations between the gate strings in the pearl-necklace encoder. We find a realization by means of a weighted graph which details the non-commutative paths through the pearl-necklace. The weight of the longest path in this graph is equal to the minimal amount of memory needed to implement the encoder. The algorithm has a polynomial-time complexity in the number of gate strings in the pearl-necklace encoder.Comment: 16 pages, 5 figures; extends paper arXiv:1004.5179v

Point Mutations on Mitochondrial DNA in Iranian Patients with Friedreich’s Ataxia

ObjectiveMitochondrial DNA (mtDNA) is considered a candidate modifier factor for neuro-degenerative disorders. The most common type of ataxia is Friedreich's ataxia (FA). The aim of this study was to investigate different parts of mtDNA in 20 Iranian FA patients and 80 age-matched controls by polymerase chain reaction (PCR) and automated DNA sequencing methods to find any probable point mutations involved in the pathogenesis of FA.Materials and MethodsWe identified 13 nucleotide substitutions including A3505G, T3335C, G3421A, G8251A, A8563G, A8563G, G8584A, T8614C, T8598C, C8684T, A8701G, G8994A and A9024G.ResultsTwelve of 13 nucleotide substitutions had already been reported as polymorphism. One of the nucleotide substitutions (A9024G) had not been reported before. The A9024G nucleotide substitution does not change its amino acid. The controls were also investigated for this polymorphism which was found in two of them (2.5%).ConclusionNone of the mutations found in this study can affect the clinical manifestations of FA. This survey also provides evidence that the mtDNA A9024G allele is a new nonpathogenic polymorphism. We suggest follow-up studies for this polymorphism in different populations.