Entanglement probe of two-impurity Kondo physics in a spin chain

We propose that real-space properties of the two-impurity Kondo model can be obtained from an effective spin model where two single-impurity Kondo spin chains are joined via an RKKY interaction between the two impurity spins. We then use a DMRG approach, valid in all ranges of parameters, to study its features using two complementary quantum-entanglement measures, the negativity and the von Neumann entropy. This non-perturbative approach enables us to uncover the precise dependence of the spatial extent $\xi_K$ of the Kondo screening cloud with the Kondo and RKKY couplings. Our results reveal an exponential suppression of the Kondo temperature $T_K \sim 1/\xi_K$ with the size of the effective impurity spin in the limit of large ferromagnetic RKKY coupling, a striking display of "Kondo resonance narrowing" in the two-impurity Kondo model. We also show how the antiferromagnetic RKKY interaction produces an effective decoupling of the impurities from the bulk already for intermediate strengths of this interaction, and, furthermore, exhibit how the non-Fermi liquid quantum critical point is signaled in the quantum entanglement between various parts of the system.Comment: 5 pages, 5 figure

Initializing an unmodulated spin chain to operate as a high quality quantum data-bus

We study the quality of state and entanglement transmission through quantum channels described by spin chains varying both the system parameters and the initial state of the channel. We consider a vast class of one-dimensional many-body models which contains some of the most relevant experimental realizations of quantum data-buses. In particular, we consider spin-1/2 XY and XXZ model with open boundary conditions. Our results show a significant difference between free-fermionic (non-interacting) systems (XY) and interacting ones (XXZ), where in the former case initialization can be exploited for improving the entanglement distribution, while in the latter case it also determines the quality of state transmission. In fact, we find that in non interacting systems the exchange with fermions in the initial state of the chain always has a destructive effect, and we prove that it can be completely removed in the isotropic XX model by initializing the chain in a ferromagnetic state. On the other hand, in interacting systems constructive effects can arise by scattering between hopping fermions and a proper initialization procedure. Remarkably our results are the first example in which state and entanglement transmission show maxima at different points as the interactions and initializations of spin chain channels are varied.Comment: 10 pages, 7 figure

Cytosolic phosphoenolpyruate carboxykinase (PEPCKC) gene polymorphism in three chicken breeds

Phosphoenolpyruate carboxykinase (PEPCK) gene is an enzyme which has a key role in gluconeogenesis. In the chicken genome, there are two different types of PEPCK gene: mitochondrial PEPCK (PEPCK-M) and cytosolic PEPCK (PEPCK-C). In this study, 150 random samples from two native populations in Sistan and Baluchistan Province, namely, Khazak and Dashtiari, and Ross chicken were analyzed. DNA was extracted from feather pulps and PCR was carried out using appropriate primers (F2R2), which amplifies a 1000 bp fragment from the chicken PEPCK-C gene. The fragment covers from promoter to exon 2 of the gene. PCR products were then digested by restriction enzymes BstEII and ACil. Allelic as well as genotypic frequencies were determined and analyzed by Popgene software. The allelic frequencies BstEII for Khazak sample were A = 0.975 and B = 0.025; for Dashtiari sample; A = 0.95 and B = 0.05 and for Ross samples, A = 0.94 and B = 0.06. The allelic frequencies digestion by ACil for Khazak sample were A = 0.86 and B = 0.14; for Dashtiari sample, A = 0.98 and B = 0.02 and for Ross samples, A = 0.95 and B = 0.05. Haplotype analysis of two single nucleotide polymorphism (SNP) showed that there were four alleles and genotypes. The present results indicated that little polymorphism exists in the samples for this locus.Key words: Polymorphism, PEPCK gene, Sistan and Baluchistan native chicken, Khazak, Dashtiari

Thermodynamic Optimization of a Geothermal Power Plant with a Genetic Algorithm in Two Stages

Due to the harmful effects and depletion of non-renewable energy resources, the major concerns are focused on using renewable energy resources. Among them, the geothermal energy has a high potential in volcano regions such as the Middle East. The optimization of an organic Rankine cycle with a geothermal heat source is investigated based on a genetic algorithm having two stages. In the first stage, the optimal variables are the depth of the well and the extraction flow rate of the geothermal fluid mass. The optimal value of the depth of the well, extraction mass flow rate, and the geothermal fluid temperature is found to be 2100 m, 15 kg/s, and 150 °C. In the second stage, the efficiency and output power of the power plant are optimized. To achieve maximum output power as well as cycle efficiency, the optimization variable is the maximum organic fluid pressure in the high-temperature heat exchanger. The optimum values of energy efficiency and cycle power production are equal to 0.433 MW and 14.1%, respectively

Intracellular ROS Protection Efficiency and Free Radical-Scavenging Activity of Curcumin

Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin showed a powerful capacity for scavenging intracellular smaller oxidative molecules such as H2O2, HO•, ROO•. Cell viability and ROS assays demonstrated that curcumin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and lethal effects of cumene hydroperoxide. Curcumin also showed good electron-transfer capability, with greater activity than trolox in aqueous solution. Curcumin can readily transfer electron or easily donate H-atom from two phenolic sites to scavenge free radicals. The excellent electron transfer capability of curcumin is because of its unique structure and different functional groups, including a β-diketone and several π electrons that have the capacity to conjugate between two phenyl rings. Therfore, since curcumin is inherently a lipophilic compound, because of its superb intracellular ROS scavenging activity, it can be used as an effective antioxidant for ROS protection within the polar cytoplasm

Effects of the alcoholic extract of white mulberry leaves on behavioral performance of rats

White mulberry tree is a genus of Morus in the family Moraceae. The leaves and root of this tree have been traditionally medical applications as a laxative, analgesic, diuretic, antitussive, and sedative agent as well as for reducing blood pressure. The present study aimed to investigate the effects of the alcoholic extract of the leaves of white mulberry tree on the behavioral performance of rats. In this study, 24 male Wistar rats were kept under the condition of normal 12-12 h light-dark cycle for adaptation with the animal house environment and experiments location (23-27C0). All animals have access to food and water ad libitum and were weighed weekly to control their natural growth. These rats were divided into four groups of six rats. First, the open field behavioral test was performed on all rats and after 35 days the gavage feeding of the alcoholic extract of white mulberry leaves was performed. Group one received distilled water and groups two to four respectively received concentrations of 150, 300, and 600 mg per unit body weight of the alcoholic extract white mulberry leaves. Then, open field behavioral test was performed again. Results showed that regarding the number of visited zones there is a significant difference between the control group and the groups receiving the extract. Up to the sixth week that the condition of all rats was identical the rate of weight increase was the same and from the seventh week on that the gavage of the hydro-alcoholic extract of white mulberry leaves began, the trend of the weight increase of the control group was different than that of the other groups. due to the effect of the alcoholic extract of white mulberry leaves on the weight of the rats at concentrations above, it can be concluded that the extract is effective for weight loss. Findings of open field test showed that this extract has anti-anxiety effects while imposing no toxic effects

Introduction of a novel 18S rDNA gene arrangement along with distinct ITS region in the saline water microalga Dunaliella

Comparison of 18S rDNA gene sequences is a very promising method for identification and classification of living organisms. Molecular identification and discrimination of different Dunaliella species were carried out based on the size of 18S rDNA gene and, number and position of introns in the gene. Three types of 18S rDNA structure have already been reported: the gene with a size of ~1770 bp lacking any intron, with a size of ~2170 bp consisting one intron near 5' terminus, and with a size of ~2570 bp harbouring two introns near 5' and 3' termini. Hereby, we report a new 18S rDNA gene arrangement in terms of intron localization and nucleotide sequence in a Dunaliella isolated from Iranian salt lakes (ABRIINW-M1/2). PCR amplification with genus-specific primers resulted in production of a ~2170 bp DNA band, which is similar to that of D. salina 18S rDNA gene containing only one intron near 5' terminus. Whilst, sequence composition of the gene revealed the lack of any intron near 5' terminus in our isolate. Furthermore, another alteration was observed due to the presence of a 440 bp DNA fragment near 3' terminus. Accordingly, 18S rDNA gene of the isolate is clearly different from those of D. salina and any other Dunaliella species reported so far. Moreover, analysis of ITS region sequence showed the diversity of this region compared to the previously reported species. 18S rDNA and ITS sequences of our isolate were submitted with accesion numbers of EU678868 and EU927373 in NCBI database, respectively. The optimum growth rate of this isolate occured at the salinity level of 1 M NaCl. The maximum carotenoid content under stress condition of intense light (400 μmol photon m-2 s-1), high salinity (4 M NaCl) and deficiency of nitrate and phosphate nutritions reached to 240 ng/cell after 15 days