Nonpropagation of tachyon on the BTZ black hole in type 0B string theory

We obtain the BTZ black hole (AdS$_3 \times$S$^3$) as a non-dilatonic solution from type 0B string theory. Analyzing the perturbation around this black hole background, we show that the tachyon is not a propagating mode.Comment: some detailed explanations are added, modified version will be appeared in Physics Letters B, 11 pages in RevTeX, no figure

Prediction of design water level due to storm surge at teh Seogwipo coastal zone in Korea

Seogwipo coastal region is known to develop coast tourist attractions and expand its harbor facilities, but this region is also more likely to get damaged by typhoons since it is affected by most of the typhoons coming into the Korean Peninsula. This study comprehended the characteristics of Jeju Island coastal areas by analyzing severe weather elements like a typhoon, and particularly reviewed design water levels by storm surge in Seogwipo Harbor. The design water level was calculated on the basis of frequency analysis results regarding extreme water levels, tidal residuals per hour and observed surges and numerical simulation-based surge heights in case of a typhoon attack, and this study also suggested problems that rapid climatic change aspects cannot be reflected recently. To solve such a problem, it is required to constantly maintain the related data and apply high-degree stormy surge numerical simulations-based plans to the present work

Electrochemical De-intercalation, Oxygen Non-stoichiometry, and Crystal Growth of NaxCoO2-d

We report a detailed study of de-intercalation of Na from the compound NaxCoO2-d using an electrochemical technique. We find evidence for stable phases with Na contents near the fractions ~1/3, 1/2, 5/8, 2/3, and 3/4. Details regarding the floating-zone crystal growth of Na0.75CoO2 single crystals are discussed as well as results from magnetic susceptibility measurements. We observe the presence of significant oxygen deficiencies in powder samples of Na0.75CoO2-d prepared in air, but not in single crystal samples prepared in an oxygen atmosphere. The oxygen deficiencies in a Na0.75CoO2-d sample with d ~ 0.08 remain even after electrochemically de-intercalating to Na0.3CoO2-d.Comment: 6 pages, 5 figure

Vibration modes of giant gravitons in the background of dilatonic D-branes

We consider the perturbation of giant gravitons in the background of dilatonic D-branes whose geometry is not of a conventional form of ${\rm AdS}_m \times {\rm S}^n$. We use the quadratic approximation to the brane action to investigate their vibrations around the equilibrium configuration. We found the normal modes of small vibrations of giant gravitons and these vibrations are turned out to be stable.Comment: 11 pages, LaTex, typos corrected, some points are clarified with comment

Extracellular Vesicles as Drug Carriers for Enzyme Replacement Therapy to Treat CLN2 Batten Disease: Optimization of Drug Administration Routes

CLN2 Batten disease (BD) is one of a broad class of lysosomal storage disorders that is characterized by the deficiency of lysosomal enzyme, TPP1, resulting in a build-up of toxic intracellular storage material in all organs and subsequent damage. A major challenge for BD therapeutics is delivery of enzymatically active TPP1 to the brain to attenuate progressive loss of neurological functions. To accomplish this daunting task, we propose the harnessing of naturally occurring nanoparticles, extracellular vesicles (EVs). Herein, we incorporated TPP1 into EVs released by immune cells, macrophages, and examined biodistribution and therapeutic efficacy of EV-TPP1 in BD mouse model, using various routes of administration. Administration through intrathecal and intranasal routes resulted in high TPP1 accumulation in the brain, decreased neurodegeneration and neuroinflammation, and reduced aggregation of lysosomal storage material in BD mouse model, CLN2 knock-out mice. Parenteral intravenous and intraperitoneal administrations led to TPP1 delivery to peripheral organs: liver, kidney, spleen, and lungs. A combination of intrathecal and intraperitoneal EV-TPP1 injections significantly prolonged lifespan in BD mice. Overall, the optimization of treatment strategies is crucial for successful applications of EVs-based therapeutics for BD

Absorption of fixed scalar in scattering off 4D N=4 black holes

We perform the perturbation analysis of the black holes in the 4D, N=4 supergravity. Analysis around the black holes reveals a complicated mixing between the dilaton and other fields (metric and two U(1) Maxwell fields). It turns out that considering both s-wave (l=0) and higher momentum modes (l \neq 0), the dilaton as a fixed scalar is the only propagating mode with $P=Q, h_1=h_2=0$ and $F = -G = 2\phi$. We calculate the absorption cross-section for scattering of low frequency waves of fixed scalar and U(1) Maxwell fields off the extremal black hole.Comment: 11 pages in RevTeX, no figures, minor correction is included(third version

Isotropic photonic band gap and anisotropic structures in transmission spectra of two-dimensional 5-fold and 8-fold symmetric quasiperiodic photonic crystals

We measured and calculated transmission spectra of two-dimensional quasiperiodic photonic crystals (PCs) based on a 5-fold (Penrose) or 8-fold (octagonal) symmetric quasiperiodic pattern. The photonic crystal consisted of dielectric cylindrical rods in air placed normal to the basal plane on vertices of tiles composing the quasiperiodic pattern. An isotropic photonic band gap (PBG) appeared in the TM mode, where electric fields were parallel to the rods, even when the real part of a dielectric constant of the rod was as small as 2.4. An isotropic PBG-like dip was seen in tiny Penrose and octagonal PCs with only 6 and 9 rods, respectively. These results indicate that local multiple light scattering within the tiny PC plays an important role in the PBG formation. Besides the isotropic PBG, we found dips depending on the incident angle of the light. This is the first report of anisotropic structures clearly observed in transmission spectra of quasiperiodic PCs. Based on rod-number and rod-arrangement dependence, it is thought that the shapes and positions of the anisotropic dips are determined by global multiple light scattering covering the whole system. In contrast to the isotropic PBG due to local light scattering, we could not find any PBGs due to global light scattering even though we studied transmission spectra of a huge Penrose PC with 466 rods.Comment: One tex file for manuscript and 12 PNG files for figures consisting of Fig.1a-d, 2,3, ...

Matter wave solitons at finite temperatures

We consider the dynamics of a dark soliton in an elongated harmonically trapped Bose-Einstein condensate. A central question concerns the behavior at finite temperatures, where dissipation arises due to the presence of a thermal cloud. We study this problem using coupled Gross-Pitaevskii and $N$-body simulations, which include the mean field coupling between the condensate and thermal cloud. We find that the soliton decays relatively quickly even at very low temperatures, with the decay rate increasing with rising temperature.Comment: 6 pages, 2 figures, submitted to the Proceedings of QFS '0

On the sample size dependence of the critical current density in MgB2_2 superconductors

Sample size dependent critical current density has been observed in magnesium diboride superconductors. At high fields, larger samples provide higher critical current densities, while at low fields, larger samples give rise to lower critical current densities. The explanation for this surprising result is proposed in this study based on the electric field generated in the superconductors. The dependence of the current density on the sample size has been derived as a power law $j\propto R^{1/n}$ ($n$ is the $n$ factor characterizing $E-j$ curve $E=E_c(j/j_c)^n$). This dependence provides one with a new method to derive the $n$ factor and can also be used to determine the dependence of the activation energy on the current density.Comment: Revtex, 4 pages, 5 figure

Density Matrix in Quantum Mechanics and Distinctness of Ensembles Having the Same Compressed Density Matrix

We clarify different definitions of the density matrix by proposing the use of different names, the full density matrix for a single-closed quantum system, the compressed density matrix for the averaged single molecule state from an ensemble of molecules, and the reduced density matrix for a part of an entangled quantum system, respectively. We show that ensembles with the same compressed density matrix can be physically distinguished by observing fluctuations of various observables. This is in contrast to a general belief that ensembles with the same compressed density matrix are identical. Explicit expression for the fluctuation of an observable in a specified ensemble is given. We have discussed the nature of nuclear magnetic resonance quantum computing. We show that the conclusion that there is no quantum entanglement in the current nuclear magnetic resonance quantum computing experiment is based on the unjustified belief that ensembles having the same compressed density matrix are identical physically. Related issues in quantum communication are also discussed.Comment: 26 pages. To appear in Foundations of Physics, 36 (8), 200