Notes on Amandinea Petermannii Comb.nov. (Physciaceae) from Antarctica

The new combination Amandinea petermannii (Hue) Matzer, Mayrh. & Scheidegger; is proposed. The taxonomy, morphology, anatomy, chemistry, ecology and distribution of this lichen are discussed. Rinodina convoluta D. C. Lindsay is synonym of A. petermanni

Out-of-Plane Magnetic Anisotropy in Ordered Ensembles of Fey_yN Nanocrystals Embedded in GaN

Phase-separated semiconductors containing magnetic nanostructures are relevant systems for the realization of high-density recording media. Here, the controlled strain engineering of Ga$\delta$FeN layers with Fe$_y$N embedded nanocrystals (NCs) \textit{via} Al$_x$Ga$_{1-x}$N buffers with different Al concentration $0<x_\mathrm{Al}<41$\% is presented. Through the addition of Al to the buffer, the formation of predominantly prolate-shaped $\varepsilon$-Fe$_3$N NCs takes place. Already at an Al concentration $x_\mathrm{Al}$\,$\approx$\,5\% the structural properties---phase, shape, orientation---as well as the spatial distribution of the embedded NCs are modified in comparison to those grown on a GaN buffer. Although the magnetic easy axis of the cubic $\gamma$'-Ga$_y$Fe$_{4-y}$N nanocrystals in the layer on the $x_\mathrm{Al} = 0\%$ buffer lies in-plane, the easy axis of the $\varepsilon$-Fe$_3$N NCs in all samples with Al$_x$Ga$_{1-x}$N buffers coincides with the $[0001]$ growth direction, leading to a sizeable out-of-plane magnetic anisotropy and opening wide perspectives for perpendicular recording based on nitride-based magnetic nanocrystals.Comment: 29 pages, 10 figures, submitte

Ultrafast coherent THz lattice dynamics coupled to spins in the van der Waals antiferromagnet FePS3

Coherent THz optical lattice and hybridized phonon–magnon modes are triggered by femtosecond laser pulses in the antiferromagnetic van der Waals semiconductor FePS3. The laser-driven lattice and spin dynamics are investigated in a bulk crystal as well as in a 380 nm-thick exfoliated flake as a function of the excitation photon energy, sample temperature and applied magnetic field. The pump-probe magneto-optical measurements reveal that the amplitude of a coherent phonon mode oscillating at 3.2 THz decreases as the sample is heated up to the Néel temperature. This signal eventually vanishes as the phase transition to the paramagnetic phase occurs, thus revealing its connection to the long-range magnetic order. In the presence of an external magnetic field, the optically triggered 3.2 THz phonon hybridizes with a magnon mode, which is utilized to excite the hybridized phonon–magnon mode optically. These findings open a pathway toward the optical control of coherent THz photo–magnonic dynamics in a van der Waals antiferromagnet, which can be scaled down to the 2D limit

Ultrafast coherent THz lattice dynamics coupled to spins in the van der Waals antiferromagnet FePS3

Coherent THz optical lattice and hybridized phonon-magnon modes are triggered by femtosecond laser pulses in the antiferromagnetic van der Waals semiconductor FePS3. The laser-driven lattice and spin dynamics are investigated in a bulk crystal as well as in a 380 nm-thick exfoliated flake as a function of the excitation photon energy, sample temperature and applied magnetic field. The pump-probe magneto-optical measurements reveal that the amplitude of a coherent phonon mode oscillating at 3.2 THz decreases as the sample is heated up to the Néel temperature. This signal eventually vanishes as the phase transition to the paramagnetic phase occurs, thus revealing its connection to the long-range magnetic order. In the presence of an external magnetic field, the optically triggered 3.2 THz phonon hybridizes with a magnon mode, which is utilized to excite the hybridized phonon- magnon mode optically. These findings open a pathway toward the optical control of coherent THz photo-magnonic dynamics in a van der Waals antiferromagnet, which can be scaled down to the 2D limit

CaMKII delta C Drives Early Adaptive Ca(2+)Change and Late Eccentric Cardiac Hypertrophy

Rationale: CaMKII (Ca2+-Calmodulin dependent protein kinase) delta C activation is implicated in pathological progression of heart failure (HF) and CaMKII delta C transgenic mice rapidly develop HF and arrhythmias. However, little is known about early spatio-temporal Ca(2+)handling and CaMKII activation in hypertrophy and HF. Objective: To measure time- and location-dependent activation of CaMKII delta C signaling in adult ventricular cardiomyocytes, during transaortic constriction (TAC) and in CaMKII delta C transgenic mice. Methods and Results: We used human tissue from nonfailing and HF hearts, 4 mouse lines: wild-type, KO (CaMKII delta-knockout), CaMKII delta C transgenic in wild-type (TG), or KO background, and wild-type mice exposed to TAC. Confocal imaging and biochemistry revealed disproportional CaMKII delta C activation and accumulation in nuclear and perinuclear versus cytosolic regions at 5 days post-TAC. This CaMKII delta activation caused a compensatory increase in sarcoplasmic reticulum Ca(2+)content, Ca(2+)transient amplitude, and [Ca2+] decline rates, with reduced phospholamban expression, all of which were most prominent near and in the nucleus. These early adaptive effects in TAC were entirely mimicked in young CaMKII delta TG mice (6-8 weeks) where no overt cardiac dysfunction was present. The (peri)nuclear CaMKII accumulation also correlated with enhanced HDAC4 (histone deacetylase) nuclear export, creating a microdomain for transcriptional regulation. At longer times both TAC and TG mice progressed to overt HF (at 45 days and 11-13 weeks, respectively), during which time the compensatory Ca(2+)transient effects reversed, but further increases in nuclear and time-averaged [Ca2+] and CaMKII activation occurred. CaMKII delta TG mice lacking delta B exhibited more severe HF, eccentric myocyte growth, and nuclear changes. Patient HF samples also showed greatly increased CaMKII delta expression, especially for CaMKII delta C in nuclear fractions. Conclusions: We conclude that in early TAC perinuclear CaMKII delta C activation promotes adaptive increases in myocyte Ca(2+)transients and nuclear transcriptional responses but that chronic progression of this nuclear Ca2+-CaMKII delta C axis contributes to eccentric hypertrophy and HF

Blushift of a tachyon in the charged 2D black hole

We study the propagation of string fields (metric $G_{\mu\nu}$, Mawxell gauge potential $A_{\mu}$, dilaton $\Phi$, and tachyon $T$) in a two-dimensional (2D) charged black hole. It is shown that the tachyon is a propagating field both inside and outside the black hole. This becomes infinitely blueshifted at the inner horizon. We confirm that the inner horizon is unstable, whereas the outer horizon is stable.Comment: 15 pages 3 figures, RevTeX, to be published Phys. Rev. D52 (15 November,1995), to obtain the figures contact Author ([email protected]

Phenotypic alterations in type II alveolar epithelial cells in CD4+ T cell mediated lung inflammation

<p>Abstract</p> <p>Background</p> <p>Although the contribution of alveolar type II epithelial cell (AEC II) activities in various aspects of respiratory immune regulation has become increasingly appreciated, our understanding of the contribution of AEC II transcriptosome in immunopathologic lung injury remains poorly understood. We have previously established a mouse model for chronic T cell-mediated pulmonary inflammation in which influenza hemagglutinin (HA) is expressed as a transgene in AEC II, in mice expressing a transgenic T cell receptor specific for a class II-restricted epitope of HA. Pulmonary inflammation in these mice occurs as a result of CD4⁺T cell recognition of alveolar antigen. This model was utilized to assess the profile of inflammatory mediators expressed by alveolar epithelial target cells triggered by antigen-specific recognition in CD4⁺T cell-mediated lung inflammation.</p> <p>Methods</p> <p>We established a method that allows the flow cytometric negative selection and isolation of primary AEC II of high viability and purity. Genome wide transcriptional profiling was performed on mRNA isolated from AEC II isolated from healthy mice and from mice with acute and chronic CD4⁺T cell-mediated pulmonary inflammation.</p> <p>Results</p> <p>T cell-mediated inflammation was associated with expression of a broad array of cytokine and chemokine genes by AEC II cell, indicating a potential contribution of epithelial-derived chemoattractants to the inflammatory cell parenchymal infiltration. Morphologically, there was an increase in the size of activated epithelial cells, and on the molecular level, comparative transcriptome analyses of AEC II from inflamed versus normal lungs provide a detailed characterization of the specific inflammatory genes expressed in AEC II induced in the context of CD4⁺T cell-mediated pneumonitis.</p> <p>Conclusion</p> <p>An important contribution of AEC II gene expression to the orchestration and regulation of interstitial pneumonitis is suggested by the panoply of inflammatory genes expressed by this cell population, and this may provide insight into the molecular pathogenesis of pulmonary inflammatory states. CD4⁺T cell recognition of antigen presented by AEC II cells appears to be a potent trigger for activation of the alveolar cell inflammatory transcriptosome.</p