5,530 research outputs found
Superconducting Quantum Point contacts and Maxwell Potential
The quantization of the current in a superconducting quantum point contact is
reviewed and the critical current is discussed at different temperatures
depending on the carrier concentration as well by suggesting a constant
potential in the semiconductor and then a Maxwell potential. When the Fermi
wave length is comparable with the constriction width we showed that the
critical current has a step-like variation as a function of the constriction
width and the carrier concentration.Comment: 13 pages, 8 figures, some figures are clarified; scheduled to appear
in an issue in MPLB Vo.21, (2007
POTENTIAL IMPACT OF COQ10 AND VITAMIN E AGAINST (STZ) INDUCED METABOLIC DETERIORATION IN THE ALBINO RATS
Objective: This study evaluates the hypoglycemic effect of COQ10 and Vitamin E are determined using STZ induced diabetic rats.Methods: Rats selected for this study were divided into five groups of ten rats each as follows: first group Normal control rats, the second is considered as diabetic groups, injected intraperitoneal with a single dose of STZ (60 mg/kg B. wt). the third group Diabetic rats orally administered glibenclamide drug 10 mg/kg B. wt daily for 30 d 4th. And 5th groups were treated orally glibenclamide combined with vitamin E (2% concentration added to the normal basal diet), or coenzyme Q10 at the dose of 10 mg/kg i. p. daily for 30 consecutive days in addition histological examinations of liver, kidney and brain were carried out to confirm the biochemical changes of the diabetic group of rats.Results: All liver enzymes activities alanine and aspartate transferases and alkaline phosphatase (AST, ALT and ALP respectively), kidney function tests; creatinine and total urea, inflammatory biomarkers; CRP, IL-10 and TNF-α. Neurotransmitters; acetylcholine and acetylcholine esterase were enhanced with the highest degree in groups treated with COQ10 or vitamin E in addition to glibenclamide dug, almost restore the normal histological architecture of liver, kidney and brain.Conclusion: Orally supplemented glibenclamide with coenzyme Q10 or vitamin E showing significantly reduced blood glucose levels in STZ induced diabetic rats. It also showed hypolipidemia as well as hepatoprotective effects, enhance histological feature of liver, kidney and brain.Â
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
Age of Betain Gneiss; implication for Late Precambrian crustal evolution in Souteastem Desert, Egypt
HAEMATOCOCCUS PLUVIALIS EXTRACT PROMOTING THE RECOVERY OF MEMORY IMPAIRMENT IN ALZHEIMER'S RATS: ANTI-INFLAMMATORY AND ANTIAPOPTOTIC EFFECTS
ABSTRACTObjective: The present study was conducted to investigate the role of Haematococcus pluvialis extract against oxidative damage, the inflammatory,and apoptotic impacts characterizing the neurodegenerative disorders.Methods: Oxidative stress, B-cell lymphoma 2, brain-derived neurotrophic factor, the inflammation, apoptotic and antiapoptotic impacts in Alzheimer'sdisease (AD) rats were determined through assessment of glutathione reduced (GSH), GSH peroxidase (GPx), lipid peroxide (malondialdehyde), thecytokines level such as tumor necrosis factor-alpha (TNF-α), interleukins (IL-6 and IL-1β), and macrophage inflammation protein (MIP1α) in AD rats.Moreover, the expression of phosphoinositide 3-kinase (PI3K) and serine-threonine protein kinase (Akt) genes regulating the apoptosis in AD ratswas measured.Results: The results revealed that levels of TNF-α, IL-6, IL-1β, and MIP1α were significantly increased in AD rats. Moreover, the expression of PI3Kand Akt genes was downregulated which it was coincided with the increase of apoptosis in AD rats. On the other hand, treatment of AD rats withH. pluvialis extract decreased the oxidative stress of AD in the form of prevention the inflammatory and apoptotic impacts.Conclusion: H. pluvialis could be used for ameliorating AD due to its role in decreases the oxidative stress of AD in the form of prevention theinflammatory and apoptotic impacts. H. pluvialis is a very attractive candidate for uses against neurodegenerative disorders that are caused byincreases oxidative stress inducing neuroinflammation and apoptosis.Keywords: Haematococcus pluvialis, Oxidative stress, Inflammation biomarkers, Apoptotic and antiapoptotic impacts
ANTINEURODEGENERATIVE ACTIVITY OF MICROALGAE DUNALIELLA SALINA IN RATS WITH ALZHEIMER'S DISEASE
Objective: The present study is aimed to investigate the promising action of Dunaliella salina extract as a natural protector against Alzheimer's disease (AD) and reported to possess a variety of activities, including antioxidant effects due to its ability to create large amount of carotenoids.Methods: D. salina is a type of halophile green microalgae was used in the present study. 50 male rats were used in this study, where aluminum chloride was orally administered to induce AD in a dose of 100 mg/kg, daily for 6 weeks. Al-intoxicated rats treated orally daily with D. salina ethanolic extract for 6 weeks in a dose of 150 mg/kg b.wt., whereas standard anti-Alzheimer drug donepezil tartrate was administered at the dose of 10 mg/kg b.wt./day for 6 consecutive weeks. The anti-Alzheimer properties of D. salina extract were achieved through measuring the calmodulin (CaM) level, paraoxonase 1 (PON1) activity, the antiapoptotic marker (Bcl2), brain-derived neurotrophic factor (BDNF), the generation of the DNA adducts (8-hydroxy-2-deoxyguanosine [8-OHdG]/2-deoxy guanosine [2-dG]), and alteration in the expression of amyloid precursor protein, β-site APP-cleaving enzyme 1 (BACE1), and β-site APP-cleaving enzyme 2 (BACE2) in AD rats.Results: The current results demonstrated that supplementation of AD rats with D. salina extract-enhanced CaM level, and increased PON1 activity, upregulated Bcl2 and BDNF, decreased the levels of DNA adducts (8-OHdG/2-dG), and suppressed the alterations of the expression levels of APP, BACE1, and BACE2-m RNAs as compared with those in AD rats.Conclusion: It could be concluded that the biological activity of D. salina extract might be regulated by 9-cis b-carotene protecting the brain cells from the oxidative stress in AD rats.Keywords: Dunaliella salina, Calmodulin, Paraoxonase 1, Bcl2, Brain-derived neurotrophic factor, Alzheimer's disease, DNA adduct, Amyloid precursor protein
A Closer Look at Precision Hard Turning of AISI4340: Multi-Objective Optimization for Simultaneous Low Surface Roughness and High Productivity
This article reports an extended investigation into the precision hard turning of AISI 4340 alloy steel when machined by two different types of inserts: wiper nose and conventional round nose. It provides a closer look at previously published work and aims at determining the optimal process parameters for simultaneously minimizing surface roughness and maximizing productivity. In the mathematical models developed by the authors, surface roughness at different cutting speeds, depths of cut and feed rates is treated as the objective function. Three robust multi-objective techniques, (1) multi-objective genetic algorithm (MOGA), (2) multi-objective Pareto search algorithm (MOPSA) and (3) multi-objective emperor penguin colony algorithm (MOEPCA), were used to determine the optimal turning parameters when either the wiper or the conventional insert is used, and the results were experimentally validated. To investigate the practicality of the optimization algorithms, two turning scenarios were used. These were the machining of the combustion chamber of a gun barrel, first with an average roughness (Ra) of 0.4 µm and then with 0.8 µm, under conditions of high productivity. In terms of the simultaneous achievement of both high surface quality and productivity in precision hard turning of AISI 4340 alloy steel, this work illustrates that MOPSA provides the best optimal solution for the wiper insert case, and MOEPCA results are the best for the conventional insert. Furthermore, the results extracted from Pareto front plots show that the wiper insert is capable of successfully meeting both the requirements of Ra values of 0.4 µm and 0.8 µm and high productivity. However, the conventional insert could not meet the 0.4 µm Ra requirement; the recorded global minimum was Ra = 0.454 µm, which reveals the superiority of the wiper compared to the conventional insert
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