Dislocation jumping over the sound barrier in tungsten

2001-2002 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Three R2R3 MYB transcription factor genes from Capsicum annuum showing differential expression during fruit ripening

Three R2R3-MYB genes, designated CaMYB1, CaMYB2 and CaMYB3, were isolated from hot pepper (Capsicum annuum. L). CaMYB1, CaMYB2 and CaMYB3 encode polypetides consisting of 340, 262 and 345 amino acids respectively, containing R2R3 domain and the signature motif specific for the interaction between MYB and bHLH proteins in the R3 domain. Phylogenetic analysis based on the deduced amino acid sequences of these three R2R3 MYB transcription factor members revealed that CaMYB1 and CaMYB2 clustered together with the anthocyanin-related subgroup of R2R3 MYB proteins from other plants, while CaMYB3 did not. CaMYBs transcripts accumulation was detected in all stages of fruit development and in flower and leaves. Three CaMYBs transcription factors showed differential expression during fruit ripening. Anthocyanin biosynthetic gene expression patterns were quite different in young leaves, flower, and the four stages of fruit development. CaMYB1 and CaMYB2 may regulate anthocyanin biosynthesis in hot pepper.Key words: Anthocyanin, Capsicum annuum, gene expression, R2R3 MYB transcription factor

Spintronic Faraday rotation spectroscopy and geometrical modulation of spin current in an Aharonov-Casher ring

We study the ballistic spin transmission through an AC ring between two ferromagnetic filter-electrodes in the presence of spin-orbit interaction, theoretically. It is shown that the spin precession of polarized electrons can be controlled via a cylindrically symmetric electric field, and the sequence of the polarized conductance depends on the relative orientation of magnetization between the left and right filters. The injected spin-polarized electrons can be blocked completely for the special values of electric field and angle of texture, which makes the magnetoresistance to be drastically enhanced. We also propose an interference scheme to detect the geometric phase.published_or_final_versio

Structural changes and effect of denopamine on alveolar fluid clearance in hypoxic rat lungs

Terbutaline (β2-adrenergic agonist) can increase alveolar fluid clearance (AFC) under physiologic and pathologic conditions. It is unknown whether 1-adrenergic agonists also increase AFC under pathologic conditions. The aim of this study was to investigate the effect of denopamine (β1- adrenergic agonist ) on AFC in hypoxic lung injury and the possible mechanisms involved. Hypoxic rats were exposed to 10% oxygen. 10-5mol/L denopamine alone or combined with β receptor antagonists, Na+ channel blocker, or Na+/K+-ATPase blocker were perfused into the alveolar space of rats exposed to 10% oxygen for 48 h. AFC and total lung water content (TLW) were measured. AFC did not change for the first 24 h but then decreased after 48h exposure to 10% oxygen. The perfusion of denopamine significantly increased AFC in normoxic and hypoxic rats. The AFC- stimulating effect of denopamine lowered with amiloride (a Na+ channel blocker) and ouabain (a Na+/K+-ATPase inhibitor) by 35 and 53%, respectively. Colchicine significantly inhibited the effect of denopamine. Denopamine can increase the AFC during hypoxic lung injury in rats and accelerate the absorption of pulmonary edema.Key words: 1-Adrenergic agonist, hypoxia, pulmonary edema, alveolar epithelium

Current-induced effect on the resistivity of epitaxial thin films of La 0.7Ca 0.3MnO 3 and La 0.85Ba 0.15MnO 3

A study was performed on the current-induced effect on the resistivity of epitaxial thin films of La 0.7Ca 0.3MnO 3 and La 0.85Ba 0.15MnO 3. The peak resistance showed a significant change at different current or current resistance. It was found that for both the compounds the dependence of the measured resistance on current revealed a good linear relationship.published_or_final_versio

Coherent oscillations and giant edge magnetoresistance in singly connected topological insulators

A topological insulator has a pair of extended states at the edge in the bulk insulating regime. We study a geometry in which such edge states will manifest themselves in a qualitative manner through periodic oscillations in the magnetoconductance of a singly connected sample coupled to leads through narrow point contacts. Detailed calculations identify the parameters for which these oscillations are expected to be the strongest, and also show their robustness to disorder. Such oscillations can be used as a spectroscopic tool of the edge states. A large change in the device resistance at small B, termed giant edge magnetoresistance, can have potential for application. © 2009 The American Physical Society.published_or_final_versio

Iterative learning control method for improving the effectiveness of upper limb rehabilitation

In rehabilitation, passive control mode is common used at early stages of the post-stroke therapy, when the impaired limb is usually unresponsive. The simplest is the use of a proportional-integral-derivative (PID) feedback control which usually regulates the position or the interaction force along a known reference. Nonetheless PID method cannot achieve an ideal tracking performance due to dynamical uncertainties and unknown time-varying periodic disturbances from the environment. In order to minimize steady-state error with respect to uncertainties in exoskeleton passive control, Iterative Learning Control(ILC) and Neural PID control are proposed to improve the control effective of conventional linear PID. In this paper, two different control algorithms are introduced. Moreover, an experimental study on a 5-DOF upper limb exoskeleton with them is addressed for comparison

Cloning and molecular characterization of a copper chaperone gene (HbCCH1) from Hevea brasiliensis

The cDNA encoding a copper chaperone, designated as HbCCH1, was isolated from Hevea brasiliensis. HbCC1 was 589 bp long containing a 261 bp open reading frame encoding a putative protein of 86 amino acids, flanked by a 103 bp 5’UTR and a 225 bp 3’UTR. The predicted molecular mass of HbCCH1 was 9.2 kDa, with an isoelectric point (pI) of 5.13. The HbCCH1 share the conserved N-terminal metalbinding domain (MXCXXC) and a lysine-rich C-terminus. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that HbCCH1 was constitutively expressed in all the tested tissues. HbCCH1 transcripts were accumulated at relatively low levels in the flower, bud and leaves, while HbCCH1 transcripts were accumulated at relatively high levels in the latex. The transcription of HbCCH1 in the latex was induced by jasmonate.Key words: Copper chaperone, Hevea brasiliensis, latex

Hole dispersions in the G- and C-type orbital ordering backgrounds: Doped manganese oxides

In the framework of the linear spin-wave theory and orbital-charge separation, we calculate quasiparticle (QP) dispersions for two different antiferromagnetic orbital structures in the fully saturated spin phase of manganese oxides. Although with the same orbital wave excitations, the QP bands of C- and G-type orbital structures exhibit completely different shapes. The pseudogap observed in the density of states and spectral functions around ω=0 is related with the large antiferromagnetic orbital fluctuation. The minimal band energy for G-type is lower than that for C-type orbital order, while these band curves almost coincide in some momentum points. Larger energy splitting occurs between the two branches of k z=0 and k z=π when increasing the superexchange coupling J, suggesting that the orbital scattering plays an essential role in the QP dispersions. ©2000 The American Physical Society.published_or_final_versio

Magnetic quantum phase transition of cold atoms in an optical lattice

We propose a scheme to investigate the magnetic phase transition of cold atoms confined in an optical lattice. We also demonstrate how to get coupled two-leg spin ladders which display a phase transition from a spin liquid to magnetic ordered state in two-dimensional optical lattice. An experimental protocol is further designed for observing this phenomenon. © 2007 The American Physical Society.published_or_final_versio