Suppressed Superconductivity of the Surface Conduction Layer in Bi2_2Sr2_2CaCu2_2O8+x_{8+x} Single Crystals Probed by {\it c}-Axis Tunneling Measurements

We fabricated small-size stacks on the surface of Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ (BSCCO-2212) single crystals with the bulk transition temperature $T_c$$\simeq$90 K, each containing a few intrinsic Josephson junctions. Below a critical temperature $T_c'$ ($\ll$ $T_c$), we have observed a weakened Josephson coupling between the CuO$_2$ superconducting double layer at the crystal surface and the adjacent one located deeper inside a stack. The quasiparticle branch in the $IV$ data of the weakened Josephson junction (WJJ) fits well to the tunneling characteristics of a d-wave superconductor($'$)/insulator/d-wave superconductor (D$'$ID) junction. Also, the tunneling resistance in the range $T_c'$$<$$T$$<$$T_c$ agrees well with the tunneling in a normal metal/insulator/d-wave superconductor (NID) junction. In spite of the suppressed superconductivity at the surface layer the symmetry of the order parameter appears to remain unaffected.Comment: 13 pages, 6 figure

Structural basis for the function and regulation of the receptor protein tyrosine phosphatase CD45

CD45 is the prototypic member of transmembrane receptor-like protein tyrosine phosphatases (RPTPs) and has essential roles in immune functions. The cytoplasmic region of CD45, like many other RPTPs, contains two homologous protein tyrosine phosphatase domains, active domain 1 (D1) and catalytically impaired domain 2 (D2). Here, we report crystal structure of the cytoplasmic D1D2 segment of human CD45 in native and phosphotyrosyl peptide-bound forms. The tertiary structures of D1 and D2 are very similar, but doubly phosphorylated CD3ζ immunoreceptor tyrosine-based activation motif peptide binds only the D1 active site. The D2 “active site” deviates from the other active sites significantly to the extent that excludes any possibility of catalytic activity. The relative orientation of D1 and D2 is very similar to that observed in leukocyte common antigen–related protein with both active sites in an open conformation and is restrained through an extensive network of hydrophobic interactions, hydrogen bonds, and salt bridges. This crystal structure is incompatible with the wedge model previously suggested for CD45 regulation

Intramolecular interactions of the regulatory domains of the Bcr–Abl kinase reveal a novel control mechanism

AbstractBackground The Abl nonreceptor tyrosine kinase is implicated in a range of cellular processes and its transforming variants are involved in human leukemias. The N-terminal regulatory region of the Abl protein contains Src homology domains SH2 and SH3 which have been shown to be important for the regulation of its activity in vivo. These domains are often found together in the same protein and biochemical data suggest that the functions of one domain can be influenced by the other.Results We have determined the crystal structure of the Abl regulatory region containing the SH3 and SH2 domains. In general, the individual domains are very similar to those of previously solved structures, although the Abl SH2 domain contains a loop which is extended so that one side of the resulting phosphotyrosine-binding pocket is open. In our structure the protein exists as a monomer with no intermolecular contacts to which a biological function may be attributed. However, there is a significant intramolecular contact between a loop of the SH3 domain and the extended loop of the SH2 domain. This contact surface includes the SH2 loop segment that is responsible for binding the phosphate moiety of phosphotyrosine-containing proteins and is therefore critical for orienting peptide interactions.Conclusions The crystal structure of the composite Abl SH3–SH2 domain provides the first indication of how SH2 and SH3 domains communicate with each other within the same molecule and why the presence of one directly influences the activity of the other. This is the first clear evidence that these two domains are in contact with each other. The results suggest that this direct interaction between the two domains may affect the ligand binding properties of the SH2 domain, thus providing an explanation for biochemical and functional data concerning the Bcr–Abl kinase

In Vitro Chemosensitivity Using the Histoculture Drug Response Assay in Human Epithelial Ovarian Cancer

The choice of chemotherapeutic drugs to treat patients with epithelial ovarian cancer has not depended on individual patient characteristics. We have investigated the correlation between in vitro chemosensitivity, as determined by the histoculture drug response assay (HDRA), and clinical responses in epithelial ovarian cancer. Fresh tissue samples were obtained from 79 patients with epithelial ovarian cancer. The sensitivity of these samples to 11 chemotherapeutic agents was tested using the HDRA method according to established methods, and we analyzed the results retrospectively. HDRA showed that they were more chemosensitive to carboplatin, topotecan and belotecan, with inhibition rates of 49.2%, 44.7%, and 39.7%, respectively, than to cisplatin, the traditional drug of choice in epithelial ovarian cancer. Among the 37 patients with FIGO stage Ⅲ/Ⅳ serous adenocarcinoma who were receiving carboplatin combined with paclitaxel, those with carboplatin-sensitive samples on HDRA had a significantly longer median disease-free interval than patients with carboplatin- resistant samples (23.2 vs. 13.8 months, p＜0.05), but median overall survival did not differ significantly (60.4 vs. 37.3 months, p＝0.621). In conclusion, this study indicates that HDRA could provide useful information for designing individual treatment strategies in patients with epithelial ovarian cancer

Tetramethyl-O-scutellarin isolated from peels of immature Shiranuhi fruit exhibits anti-inflammatory effects on LPSinduced RAW264.7 cells

Purpose: To investigate the anti-inflammatory activity of the ethanol extract of the immature fruit of a citrus, Shiranuhi, and to identify the active ingredient.Methods: The immature Shiranuhi peel was extracted with 80 % ethanol, and the extract was fractionated with solvents (n-hexane, ethyl acetate and n-butanol) to afford the corresponding fractions and water residue. Among them, the EtOAc-soluble portion was subjected to medium pressure liquid chromatography (MPLC) over a reversed-phase SiO2 column to give compound 1. The isolated compound was identified based on the proton and carbon nuclear magnetic resonance (NMR) spectra. The release of nitric oxide, prostaglandin (PG)E2, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 secreted by mouse macrophages was measured using RAW264.7 cell culture supernatant.Results: Shiranuhi (Korean name, Hallabong) is an important citrus species cultivated in Jeju Island, Korea. A polymethoxyflavonoid (PMF), tetramethyl-O-scutellarin (1), was isolated from the peels of immature Shiranuhi fruit. Upon the evaluation of anti-inflammatory effects, the flavonoid 1 decreased the nitric oxide production in macrophage cells with high efficiency, viz, 50 % inhibition concentration, IC50 of 57.4 μM. Subsequent studies demonstrated that PMF 1 effectively inhibited the generation of PGE2, TNF-α, IL-1β, and IL-6 cytokine in a dose-dependent manner.Conclusion: Tetramethyl-O-scutellarin (1) has been successfully isolated from Shiranuhi species for the first time. Thus, Shiranuhi fruit peel extract containing PMF 1 can potentially be applied as an antiinflammatory ingredient in food or cosmetic industries.Keywords: Shiranuhi fruit, Nitric oxide, Tetramethyl-O-scutellarin, Anti-inflammator

AoA-based Position and Orientation Estimation Using Lens MIMO in Cooperative Vehicle-to-Vehicle Systems

Positioning accuracy is a critical requirement for vehicle-to-everything (V2X) use cases. Therefore, this paper derives the theoretical limits of estimation for the position and orientation of vehicles in a cooperative vehicle-to-vehicle (V2V) scenario, using a lens-based multiple-input multiple-output (lens-MIMO) system. Following this, we analyze the Cram$\acute{\text{e}}$r-Rao lower bounds (CRLBs) of the position and orientation estimation and explore a received signal model of a lens-MIMO for the particular angle of arrival (AoA) estimation with a V2V geometric model. Further, we propose a lower complexity AoA estimation technique exploiting the unique characteristics of the lens-MIMO for a single target vehicle; as a result, its estimation scheme is effectively extended by the successive interference cancellation (SIC) method for multiple target vehicles. Given these AoAs, we investigate the lens-MIMO estimation capability for the positions and orientations of vehicles. Subsequently, we prove that the lens-MIMO outperforms a conventional uniform linear array (ULA) in a certain configuration of a lens's structure. Finally, we confirm that the proposed localization algorithm is superior to ULA's CRLB as the resolution of the lens increases in spite of the lower complexity.Comment: 16 pages, 11 figure

Quantum diamond microscopy with sub-ms temporal resolution

Quantum diamond magnetometers using lock-in detection have successfully detected weak bio-magnetic fields from neurons, a live mammalian muscle, and a live mouse heart. This opens up the possibility of quantum diamond magnetometers visualizing microscopic distributions of the bio-magnetic fields. Here, we demonstrate a lock-in-based wide-field quantum diamond microscopy, achieving a mean volume-normalized per pixel sensitivity of 43.9 $\mathrm{nT\cdot\mu m^{1.5}/Hz^{0.5}}$. We obtain the sensitivity by implementing a double resonance with hyperfine driving and magnetic field alignment along the $$ orientation of the diamond. Additionally, we have demonstrated that sub-ms temporal resolution ($\sim$ 0.4 ms) can be achieved at a micrometer scale with tens of nanotesla per-pixel sensitivity using quantum diamond microscopy. This lock-in-based diamond quantum microscopy could be a step forward in mapping functional activity in neuronal networks in micrometer spatial resolution

Temperature-insensitive flexible polymer wavelength filter fabricated on polymer substrates

Temperature-insensitive polymer wavelength filters with silicon nitride gratings were fabricated on a polymer substrate. Polymer waveguides on polymer substrates were fabricated on top of the Si wafer with a water soluble poly(vinylalcohol) (PVA) interlayer between the Si wafer and polymer waveguides. After the completion of the waveguides, the polymer waveguides are separated from the substrate by dissolving the PVA layer to form all polymer waveguides. The novel process provides a way to overcome the problem of the thermal instability of polymer substrate when the polymer waveguides are directly fabricated on polymer substrates. The polymeric wavelength filter fabricated on a polymer substrate exhibits one order of magnitude lower Bragg wavelength shift with temperature than the device on the Si-wafer in the temperature range of 25–70 °C, which is consistent with theoretical prediction.The authors thank the KOSET through CRM for financial support of this work