Investigation of LiFeAs by means of "Break-junction" Technique

In our tunneling investigation using Andreev superconductor - normal metal - superconductor contacts on LiFeAs single crystals we observed two reproducible independent subharmonic gap structures at dynamic conductance characteristics. From these results, we can derive the energy of the large superconducting gap $\Delta_L=(2.5 \div 3.4)$ meV and the small gap $\Delta_L=(0.9 \div 1)$ meV at $T = 4.2$ K for the $T_C^{local} \approx (10.5 \div 14)$ K (the contact area critical temperature which deviation causes the variation of $\Delta_L$). The BCS-ratio is found to be $2\Delta_L/k_BT_C = (4.6 \div 5.6)$, whereas $2\Delta_S/k_BT_C \ll 3.52$ results from induced superconductivity in the bands with the small gap.Comment: 7 pages, 5 figures. Published in Pis'ma v ZhETF 95, 604-610 (2012

Local electromechanical properties of barium strontium titanate based glass-ceramics

The equipment of the Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Foundation for Basic Research (Grant 18-52-53032)

In situ study of fiber structure development of poly(butylene terephthalate) in a continuous laser-heated drawing process

The structural development of poly(butylene terephthalate) (PBT) fibers was analyzed using in situ wide angle X-ray diffraction and fiber temperature measurements during CO2 laser-heated drawing, in which the necking position on the running fiber could be fixed by CO2 laser irradiation. The measured parameters were determined as functions of the elapsed time after necking with a time resolution of 0.3 ms. The as-spun PBT fibers, which exhibited a low-oriented alpha-crystalline structure, were drawn to a draw ratio of 5 using laser heating. The (001') reflection, which indicates a quasi-smectic fibrillar structure, was not observed before crystallization in contrast to measurements of poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalene dicarboxylate) (PEN). The alpha-crystal was transformed into an oriented beta-form crystal at the necking position, and the developed beta-crystallites exhibited increased size and altered orientation <2 ms after necking. The fiber temperature increased rapidly at around T-g, and the rearrangement of the beta-crystal primarily occurred as the fiber's temperature rose from 100 to 160 degrees C. The oriented beta-crystal of the drawn fiber transformed into the oriented beta-crystal when the drawing tension was released. Polymer Journal (2012) 44, 1030-1035; doi: 10.1038/pj.2012.65; published online 18 April 2012ArticlePOLYMER JOURNAL. 44(10):1030-1035 (2012)journal articl

Modified gravity and its reconstruction from the universe expansion history

We develop the reconstruction program for the number of modified gravities: scalar-tensor theory, $f(R)$, $F(G)$ and string-inspired, scalar-Gauss-Bonnet gravity. The known (classical) universe expansion history is used for the explicit and successful reconstruction of some versions (of special form or with specific potentials) from all above modified gravities. It is demonstrated that cosmological sequence of matter dominance, decceleration-acceleration transition and acceleration era may always emerge as cosmological solutions of such theory. Moreover, the late-time dark energy FRW universe may have the approximate or exact $\Lambda$CDM form consistent with three years WMAP data. The principal possibility to extend this reconstruction scheme to include the radiation dominated era and inflation is briefly mentioned. Finally, it is indicated how even modified gravity which does not describe the matter-dominated epoch may have such a solution before acceleration era at the price of the introduction of compensating dark energy.Comment: LaTeX file, 24 pages, no figure, prepared for the proceedings of ERE 2006, minor correction

PI3Ks Maintain the Structural Integrity of T-Tubules in Cardiac Myocytes

Phosphoinositide 3-kinases (PI3Ks) regulate numerous physiological processes including some aspects of cardiac function. Although regulation of cardiac contraction by individual PI3K isoforms has been studied, little is known about the cardiac consequences of downregulating multiple PI3Ks concurrently.Genetic ablation of both p110α and p110β in cardiac myocytes throughout development or in adult mice caused heart failure and death. Ventricular myocytes from double knockout animals showed transverse tubule (T-tubule) loss and disorganization, misalignment of L-type Ca(2+) channels in the T-tubules with ryanodine receptors in the sarcoplasmic reticulum, and reduced Ca(2+) transients and contractility. Junctophilin-2, which is thought to tether T-tubules to the sarcoplasmic reticulum, was mislocalized in the double PI3K-null myocytes without a change in expression level.PI3K p110α and p110β are required to maintain the organized network of T-tubules that is vital for efficient Ca(2+)-induced Ca(2+) release and ventricular contraction. PI3Ks maintain T-tubule organization by regulating junctophilin-2 localization. These results could have important medical implications because several PI3K inhibitors that target both isoforms are being used to treat cancer patients in clinical trials

Observation of the electromagnetic doubly OZI-suppressed decay J/ψ→ϕπ0J/\psi \rightarrow \phi \pi^{0}

Using a sample of $1.31$ billion $J/\psi$ events accumulated with the BESIII detector at the BEPCII collider, we report the observation of the decay $J/\psi \rightarrow \phi\pi^{0}$, which is the first evidence for a doubly Okubo-Zweig-Iizuka suppressed electromagnetic $J/\psi$ decay. A clear structure is observed in the $K^{+} K^{-}$ mass spectrum around 1.02 GeV/$c^2$, which can be attributed to interference between $J/\psi \rightarrow \phi\pi^{0}$ and $J/\psi \rightarrow K^{+}K^{-}\pi^{0}$ decays. Due to this interference, two possible solutions are found. The corresponding measured values of the branching fraction of $J/\psi \to \phi\pi^{0}$ are $[2.94 \pm 0.16\text{(stat.)} \pm 0.16\text{(syst.)}] \times 10^{-6}$ and $[1.24 \pm 0.33\text{(stat.)} \pm 0.30\text{(syst.)}] \times 10^{-7}$.Comment: 7 pages, 4 figures, published in Phys. Rev.

Advances in small lasers

M.T.H was supported by an Australian Research council Future Fellowship research grant for this work. M.C.G. is grateful to the Scottish Funding Council (via SUPA) for financial support.Small lasers have dimensions or modes sizes close to or smaller than the wavelength of emitted light. In recent years there has been significant progress towards reducing the size and improving the characteristics of these devices. This work has been led primarily by the innovative use of new materials and cavity designs. This Review summarizes some of the latest developments, particularly in metallic and plasmonic lasers, improvements in small dielectric lasers, and the emerging area of small bio-compatible or bio-derived lasers. We examine the different approaches employed to reduce size and how they result in significant differences in the final device, particularly between metal- and dielectric-cavity lasers. We also present potential applications for the various forms of small lasers, and indicate where further developments are required.PostprintPeer reviewe

Dendrite microstructure of barium strontium titanate based glass-ceramics

The research was made possible by Russian Foundation for Basic Research (Grant 18-52-53032‐NNSF‐a). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used

Phellinus linteus sensitises apoptosis induced by doxorubicin in prostate cancer

It has been demonstrated that the Phellinus linteus (PL) mushroom, which mainly consists of polysaccharides, possesses antitumour activity. The mechanisms of PL against malignant growth remain unknown. The anticancer drug doxorubicin (Dox) has been shown to induce apoptosis via initiating a caspase cascade. In this investigation, we tested the effect of PL on Dox-induced apoptosis in prostate cancer LNCaP cells. We showed that PL or Dox, at relatively low doses, does not induce apoptosis in the cells. However, combination treatment with low doses of PL and Dox results in a synergistic effect on the induction of apoptosis. In this apoptotic process, caspases 8, 3 and BID are cleaved, and the addition of caspase inhibitor z-VADfmk completely blocks apoptosis. In addition, JNK is activated in response to PL or the combination treatment in LNCaP cells. The suppression of JNK partially inhibits the induction of apoptosis elicited by the co-treatment. These findings indicate that PL has a synergistic effect with Dox to activate caspases in prostate cancer LNCaP cells. Our study also suggests that PL has therapeutic potential to augment the magnitude of apoptosis induced by antiprostate cancer drugs

Spintronics: Fundamentals and applications

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio