1,3-Dioxo-2,3-dihydro-1H-isoindol-2-yl 2,3,4-tri-O-acetyl-β-d-xyloside

The title compound, C19H19NO10, was obtained from the reaction of α-d-1-bromo-2,3,4-tri-O-acetylxylose with N-hy­droxy­phthalimide in the presence of potassium carbonate. The asymmetric unit contains two independent mol­ecules, in which the O—CH—O—N torsion angles are 73.0 (4) and 65.0 (4)°. The hexa­pyranosyl rings adopt chair conformations and the substituent groups are in equatorial positions. In the crystal, mol­ecules are linked by nonclassical C—H⋯O hydrogen bonds

Comparing Enterovirus 71 with Coxsackievirus A16 by analyzing nucleotide sequences and antigenicity of recombinant proteins of VP1s and VP4s

<p>Abstract</p> <p>Background</p> <p>Enterovirus 71 (EV71) and Coxsackievirus A16 (CA16) are two major etiological agents of Hand, Foot and Mouth Disease (HFMD). EV71 is associated with severe cases but not CA16. The mechanisms contributed to the different pathogenesis of these two viruses are unknown. VP1 and VP4 are two major structural proteins of these viruses, and should be paid close attention to.</p> <p>Results</p> <p>The sequences of <it>vp1s </it>from 14 EV71 and 14 CA16, and <it>vp4s </it>from 10 EV71 and 1 CA16 isolated in this study during 2007 to 2009 HFMD seasons were analyzed together with the corresponding sequences available in GenBank using DNAStar and MEGA 4.0. Phylogenetic analysis of complete <it>vp1s </it>or <it>vp4s </it>showed that EV71 isolated in Beijing belonged to C4 and CA16 belonged to lineage B2 (lineage C). VP1s and VP4s from 4 strains of viruses expressed in <it>E. coli BL21 </it>cells were used to detect IgM and IgG in human sera by Western Blot. The detection of IgM against VP1s of EV71 and CA16 showed consistent results with current infection, while none of the sera were positive against VP4s of EV71 and CA16. There was significant difference in the positive rates between EV71 VP1 and CA16 VP1 (χ²= 5.02, P < 0.05) as well as EV71 VP4 and CA16 VP4 (χ²= 15.30, P < 0.01) in the detection of IgG against recombinant proteins with same batch of serum samples. The sera-positive rate of IgG against VP1 was higher than that against VP4 for both EV71 (χ²= 26.47, P < 0.01) and CA16 (χ²= 16.78, P < 0.01), which might be because of different positions of VP1 and VP4 in the capsid of the viruses.</p> <p>Conclusions</p> <p>EV71 and CA16 were highly diverse in the nucleotide sequences of <it>vp1s </it>and <it>vp4s</it>. The sera positive rates of VP1 and VP4 of EV71 were lower than those of CA16 respectively, which suggested a less exposure rate to EV71 than CA16 in Beijing population. Human serum antibodies detected by Western blot using VP1s and VP4s as antigen indicated that the immunological reaction to VP1 and VP4 of both EV71 and CA16 was different.</p

Ultrabroadband mid-infrared emission from Cr 2+ -doped infrared transparent chalcogenide glass ceramics embedded with thermally grown ZnS nanorods

We report, for the first time to our knowledge, an ultrabroadband mid-infrared (MIR) emission in the range of 1800–2800 nm at room temperature from a Cr2+-doped chalcogenide glass ceramic embedded with pure hexagonal (wurtzite) β-ZnS nanorods and study the emission-dependent properties on the doping concentration of Cr2+. A new family of chalcogenide glasses based on (100 − x) Ge1.5As2S6.5 – x ZnSe (in mol.%) was prepared by melt-quenching method. The Cr2+: β-ZnS nanorods of ˜150 nm in diameter and ˜1 μm in length were grown in the Cr2+-doped glass after thermal annealing. The compositional variations of glass structures and optical properties were studied. The crystalline phase, morphology of the thermally grown nanorods, and the microscopic elemental distributions were characterized using advanced nanoscale transmission electron microscopy analyses

Crystal-field Engineering of Ultrabroadband Mid-infrared Emission in Co2+-doped Nano-chalcogenide Glass Composites

unable and ultrabroadband mid-infrared (MIR) emissions in the range of 2.5–4.5 μm are firstly reported from Co2+-doped nano-chalcogenide (ChG) glass composites. The composites embedded with a variety of binary (ZnS, CdS, ZnSe) and ternary (ZnCdS, ZnSSe) ChG nanocrystals (NCs) can be readily obtained by a simple one-step thermal annealing method. They are highly transparent in the near- and mid-infrared wavelength region. Low-cost and commercially available Er3+-doped fiber lasers can be used as the excitation source. By crystal-field engineering of the embedded NCs through cation- or anion-substitution, the emission properties of Co2+ including its emission peak wavelength and bandwidth can be tailored in a broad spectral range. The phenomena can be accounted for by crystal-field theory. Such nano-ChG composites, perfectly filling the 3–4 μm spectral gap between the oscillations of Cr2+ and Fe2+ doped IIVI ChG crystals, may find important MIR photonic applications (e.g., gas sensing), or can be used directly as an efficient pump source for Fe2+: IIVI crystals which are suffering from lack of pump sources

Third-order optical nonlinearity properties of CdCl2-modifed Ge–Sb–S chalcogenide glasses

We developed a new type of chalcohalide glasses with physicochemical and nonlinear optical properties that are tunable by composition. It is found that more than 60 mol.% CdCl2 heavy metal halide can be dissolved into the ternary Ge–Sb–S system and forming stable glasses. The visible-light transparency range is extended to shorter wavelengths with the addition of CdCl2, which is beneficial for the optical quality control and infra-red (IR) system alignment. The third-order optical nonlinearity (TONL) is studied using the femtosecond Z-scan method. The results show that both the nonlinear refractive index and two photon absorption co-efficient decrease with CdCl2. Benefiting from the favorable property-tailoring effects of CdCl2, the TONL figure of merit (FOM) can be improved to meet the requirement (FOM \u3c 1) for all-optical switching and IR photonic applications

Ultrasonographic diagnosis of ovarian tumors through the deep convolutional neural network

Objectives: The objective of this study was to develop and validate an ovarian tumor ultrasonographic diagnostic model based on deep convolutional neural networks (DCNN) and compare its diagnostic performance with that of human experts. Material and methods: We collected 486 ultrasound images of 192 women with malignant ovarian tumors and 617 ultrasound images of 213 women with benign ovarian tumors, all confirmed by pathological examination. The image dataset was split into a training set and a validation set according to a 7:3 ratio. We selected 5 DCNNs to develop our model: MobileNet, Xception, Inception, ResNet and DenseNet. We compared the performance of the five models through the area under the curve (AUC), sensitivity, specificity, and accuracy. We then randomly selected 200 images from the validation set as the test set. We asked three expert radiologists to diagnose the images to compare the performance of radiologists and the DCNN model. Results: In the validation set, AUC of DenseNet was 0.997 while AUC was 0.988 of ResNet, 0.987 of Inception, 0.968 of Xception and 0.836 of MobileNet. In the test set, the accuracy was 0.975 with the DenseNet model versus 0.825 (p &lt; 0.0001) with the radiologists, and sensitivity was 0.975 versus 0.700 (p &lt; 0.0001), and specificity was 0.975 versus 0.908 (p &lt; 0.001). Conclusions: DensNet performed better than other DCNNs and expert radiologists in identifying malignant ovarian tumors from benign ovarian tumors based on ultrasound images, a finding that needs to be further explored in clinical trials

Observation of plateau regions for zero bias peaks within 5% of the quantized conductance value 2e2/h2e^2/h

Probing an isolated Majorana zero mode is predicted to reveal a tunneling conductance quantized at $2e^2/h$ at zero temperature. Experimentally, a zero-bias peak (ZBP) is expected and its height should remain robust against relevant parameter tuning, forming a quantized plateau. Here, we report the observation of large ZBPs in a thin InAs-Al hybrid nanowire device. The ZBP height can stick close to $2e^2/h$, mostly within 5% tolerance, by sweeping gate voltages and magnetic field. We further map out the phase diagram and identify two plateau regions in the phase space. Our result constitutes a step forward towards establishing Majorana zero modes.Comment: Raw data and processing codes within this paper are available at https://doi.org/10.5281/zenodo.654697

Gate-Compatible Circuit QED in a Three-Dimensional Cavity Architecture

Semiconductor-based superconducting qubits offer a versatile platform for studying hybrid quantum devices in circuit quantum electrodynamics (cQED) architecture. Most of these cQED experiments utilize coplanar waveguides, where the incorporation of DC gate lines is straightforward. Here, we present a technique for probing gate-tunable hybrid devices using a three-dimensional (3D) microwave cavity. A recess is machined inside the cavity wall for the placement of devices and gate lines. We validate this design using a hybrid device based on an InAs-Al nanowire Josephson junction. The coupling between the device and the cavity is facilitated by a long superconducting strip, the antenna. The Josephson junction and the antenna together form a gatemon qubit. We further demonstrate the gate-tunable cavity shift and two-tone qubit spectroscopy. This technique could be used to probe various quantum devices and materials in a 3D cQED architecture that requires DC gate voltages

Ballistic PbTe Nanowire Devices

Disorder is the primary obstacle in current Majorana nanowire experiments. Reducing disorder or achieving ballistic transport is thus of paramount importance. In clean and ballistic nanowire devices, quantized conductance is expected with plateau quality serving as a benchmark for disorder assessment. Here, we introduce ballistic PbTe nanowire devices grown using the selective-area-growth (SAG) technique. Quantized conductance plateaus in units of $2e^2/h$ are observed at zero magnetic field. This observation represents an advancement in diminishing disorder within SAG nanowires, as none of the previously studied SAG nanowires (InSb or InAs) exhibit zero-field ballistic transport. Notably, the plateau values indicate that the ubiquitous valley degeneracy in PbTe is lifted in nanowire devices. This degeneracy lifting addresses an additional concern in the pursuit of Majorana realization. Moreover, these ballistic PbTe nanowires may enable the search for clean signatures of the spin-orbit helical gap in future devices