Shot noise of spin current and spin transfer torque

We report the theoretical investigation of noise spectrum of spin current and spin transfer torque for non-colinear spin polarized transport in a spin-valve device which consists of normal scattering region connected by two ferromagnetic electrodes. Our theory was developed using non-equilibrium Green's function method and general non-linear $S^\sigma-V$ and $S^\tau-V$ relations were derived as a function of angle $\theta$ between magnetization of two leads. We have applied our theory to a quantum dot system with a resonant level coupled with two ferromagnetic electrodes. It was found that for the MNM system, the auto-correlation of spin current is enough to characterize the fluctuation of spin current. For a system with three ferromagnetic layers, however, both auto-correlation and cross-correlation of spin current are needed to characterize the noise spectrum of spin current. Furthermore, the spin transfer torque and the torque noise were studied for the MNM system. For a quantum dot with a resonant level, the derivative of spin torque with respect to bias voltage is proportional to $\sin\theta$ when the system is far away from the resonance. When the system is near the resonance, the spin transfer torque becomes non-sinusoidal function of $\theta$. The derivative of noise spectrum of spin transfer torque with respect to the bias voltage $N_\tau$ behaves differently when the system is near or far away from the resonance. Specifically, the differential shot noise of spin transfer torque $N_\tau$ is a concave function of $\theta$ near the resonance while it becomes convex function of $\theta$ far away from resonance. For certain bias voltages, the period $N_\tau(\theta)$ becomes $\pi$ instead of $2\pi$. For small $\theta$, it was found that the differential shot noise of spin transfer torque is very sensitive to the bias voltage and the other system parameters.Comment: 15pages, 6figure

SLUG is activated by nuclear factor kappa B and confers human alveolar epithelial A549 cells resistance to tumor necrosis factor-alpha-induced apoptosis

BACKGROUND: The role of tumor necrosis factor alpha (TNF-α) in cancer is complex with both apoptotic and anti-apoptotic roles proposed. However the mechanism is not clear. In the study, we designed to investigate the effect of TNF-α on the activation and expression of nuclear factor kappa B (NF-κB)/p65/SLUG/PUMA/Bcl-2 levels in human lung cancer A549 cell line, and in conditions of TNF-α-induced apoptosis. METHODS: We have engineered three A549 cell lines that were transiently transfected with PUMA siRNA, SLUG siRNA and Bcl-2 siRNA, respectively. We have measured the in vitro effects of siRNA on apoptosis, and sensitivity to 20 ng/ml of TNF-α treatment for 24–48 h. RESULTS: We found the NF-κB activity and PUMA mRNA/protein was significantly increased after treatment of TNF-α for 24 h in untreated A549 cells, and led to a significant increase in TNF-α-induced apoptosis, no significant increase of SLUG and Bcl-2 level was shown. However, after treatment of TNF-α for 48 h in untreated A549 cells, SLUG and Bcl-2 level was significant increased, and PUMA level was significant decreased, and TNF-α-induced apoptosis was significantly decreased compared to the apoptosis level after treatment of TNF-α for 24 h. Inhibition of the NF-κB activity could effectively decrease the PUMA level and increase the SLUG and Bcl-2 level. PUMA silencing by siRNA led to a significant decrease in TNF-α-induced apoptosis after treatment of TNF-α for 24 h. Bcl-2 and SLUG silencing by siRNA led to a significant increase in TNF-α-induced apoptosis for 48 h. Furthermore, SLUG silencing increased PUMA level and decreased Bcl-2 level. CONCLUSIONS: The findings suggested that TNF-α treatment promoted apoptosis via the NF-κB-dependent PUMA pathway. The anti-apoptotic role of TNF-α was via NF-κB-dependent SLUG and Bcl-2 pathway at a later time

New universal gates for topological quantum computation with Fibonacci-ε\boldsymbol{\varepsilon} composite Majorana edge modes on topological superconductor multilayers

We propose a new design of universal topological quantum computer device through a hybrid of the 1-, 2- and 7-layers of chiral topological superconductor ($\chi$TSC) thin films. Based on the $SO(7)_1/(G_2)_1$ coset construction, strongly correlated Majorana fermion edge modes on the 7-layers of $\chi$TSC are factorized into the composite of the Fibonacci $\tau$-anyon and $\varepsilon$-anyon modes in the tricritical Ising model. Furthermore, the deconfinement of $\tau$ and $\varepsilon$ via the interacting potential gives the braiding of either $\tau$ or $\varepsilon$. Topological phase gates are assembled by the braidings. With these topological phase gates, we find a set of fully topological universal gates for the $(\tau,\varepsilon)$ composite Majorana-Ising-type quantum computation. Because the Hilbert space still possesses a tensor product structure of quibts and is characterized by the fermion parities, encoding quantum information in this machine is more efficient and substantial than that with Fibonacci anyons. The computation results is easier to be read out by electric signals, so are the initial data inputted.Comment: 6 pages, 3 figues, revised versio

A New Species of Genus Microhyla (Amphibia: Anura: Microhylidae) from Zhejiang Province, China

We described a new species, Microhyla beilunensis sp. nov., from Zhejiang Province of China. Phylogenetic analyses based on the mitochondrial 12S, 16S and CO1 gene sequences suggested that the new taxon was distinctly separated from its congeners and closed to M. mixtura and M. okinavensis. Morphologically, the new species could be identified from its congeners except M. mixtura by several characters: (1) rudimentary webs on toe base; (2) absence of disks and dorsal median longitudinal grooves on finger tips; (3) presence of disks and dorsal median longitudinal grooves on toe tips. As well, the new species could be identified from topotype M. mixtura by the combination of characters: (1) apart from the stripes, bar-shaped and oval-shaped patterns, the rounded spots present on the dorsum of body and legs; (2) the outer metacarpal tubercles prominently larger than the inner one; (3) of males, the ratios of HW, IND, UEW and LAW to SVL of the new species were significantly larger than those of M. mixtura (P < 0.01), and the ratios of SL, IOD, LAHL, HLL, TL, TFL and FL to SVL of the new species were significantly less than those of M. mixtura (P < 0.05)

Incidence of biliary atresia associated congenital malformations: A retrospective multicenter study in China

SummaryBackgroundSome patients with biliary atresia (BA) have associated anomalies. Our study aimed to investigate the incidence of BA-associated malformations in mainland China, and compare the results with those reported in the Western literature.MethodsClinical data were collected retrospectively from five medical centers in mainland China. BA patients were diagnosed and confirmed by laparotomy with intraoperative cholangiography and liver biopsy. Cases were divided into isolated type BA and BA with associated anomalies, including polysplenia, situs inversus, intestinal malrotation, and cardiovascular anomalies.ResultsA total of 851 BA patients were recruited from Tianjin, Beijing, Wuhan, Guangzhou, and Shenzhen. Patients were grouped as follows: Type I, 13 cases (1.5%); Type II, five cases (0.6%); Type III, 833 cases (97.9%). Forty-two (4.94%) patients had 54 associated congenital abnormalities. The intra-abdominal anomalies included polysplenia (n = 4, 1 fusion between liver and spleen), situs inversus (n = 2), and intestinal malrotation (n = 3). The cardiovascular anomalies included atrial septal defect and ventricular septal defect (n = 29), patent foramen ovale (n = 1), patent ductus arteriosus (n = 4), and other cardiac malformations (n = 3, including coronary sinus dilation, left superior vena cava, Tetralogy of Fallot).ConclusionOur data showed that spleen anomaly is not as common as reported in the Western literature. The difference may suggests different genetic and environmental risk factors for BA

15-Hydroxy­ethyl-19-isopropyl-5,9-dimethyl-14,16-dioxo-15-aza­penta­cyclo­[10.5.2.01,10.04,9.013,17]nona­dec-18-ene-5-carboxylic acid

The title compound, C26H37NO5, which was synthesized from monoethano­lamine and maleopimaric acid, consists of two fused and unbridged cyclo­hexane rings. They form a trans ring junction with a chair conformation. The two methyl groups are in axial positions. In the crystal, inter­molecular O—H⋯O hydrogen bonds link adjacent mol­ecules into a layer structure. Two C—H⋯O interactions are also present