Frequency-selective time-domain optical data storage by electromagnetically induced transparency in a rare-earth-doped solid

We report the experimental observation of optical data storage by frequency-selective stimulated spin echoes based on electromagnetically induced transparency in an inhomogeneously broadened rare-earth-doped solid. We find that the spin dephasing time T(2) is almost constant in the range 2-6 K, whereas the optical T(2) shortens rapidly above 4 K. This experiment demonstrates the potential of spin echoes excited by electromagnetically induced transparency for higher-capacity optical data storage at higher temperature.     

A Cyclized Helix‐Loop‐Helix Peptide as a Molecular Scaffold for the Design of Inhibitors of Intracellular Protein–Protein Interactions by Epitope and Arginine Grafting

The design of inhibitors of intracellular protein–protein interactions (PPIs) remains a challenge in chemical biology and drug discovery. We propose a cyclized helix‐loop‐helix (cHLH) peptide as a scaffold for generating cell‐permeable PPI inhibitors through bifunctional grafting: epitope grafting to provide binding activity, and arginine grafting to endow cell‐permeability. To inhibit p53–HDM2 interactions, the p53 epitope was grafted onto the C‐terminal helix and six Arg residues were grafted onto another helix. The designed peptide cHLHp53‐R showed high inhibitory activity for this interaction, and computational analysis suggested a binding mode for HDM2. Confocal microscopy of cells treated with fluorescently labeled cHLHp53‐R revealed cell membrane penetration and cytosolic localization. The peptide inhibited the growth of HCT116 and LnCap cancer cells. This strategy of bifunctional grafting onto a well‐structured peptide scaffold could facilitate the generation of inhibitors for intracellular PPIs.     

Coherence switching in a four-level system: quantum switching

Dark resonance switching among three-laser interactions in a four-level system is observed by using an enhanced nondegenerate four-wave mixing technique. This coherence switching mechanism is based on simultaneous suppression and enhancement of two-photon absorption and has a novel application to high-speed optical switches.     

Enhancement of four-wave mixing and line narrowing by use of quantum coherence in an optically dense double-? solid

We have demonstrated enhanced nondegenerate four-wave mixing by use of a resonant probe in a double- ? system consisting of an optically dense spectral hole-burning solid. The observed probe diffraction efficiency is ~16% in amplitude at 6 K, which is higher than for an off-resonant probe in a ? -type scheme. We have also observed two-photon coherence line narrowing, which has potential application to high-resolution spectroscopy.     

Preparation of MnCo2O4.5@Co(OH)2 composites on nickel foam as supercapacitor electrodes

Journal of Solid State Electrochemistry - In this work, Co(OH)2 nanosheets were successfully deposited on the hydrothermally prepared MnCo2O4.5 nanowires by the electrodeposition method to obtain...     

Cu2+-induced intermolecular static excimer formation of pyrenealkylamine

Synthesis of monopyrenylalkylamine derivative 1 and its fluorescence behavior for Cu2+ in H2O/CH3CN (1:1, v/v) were investigated. Upon Cu2+ binding, 1, bearing a sulfonamide group, exhibited a marked excimer emission at 455 nm along with a weak monomer emission at 375 nm. The excimer emission, driven by formation of an intermolecular pyrenyl static excimer upon Cu2+ binding to the sulfonamide group, is rationalized by experimental and theoretical DFT calculation results.     

Simultaneous quantitation of 17 female sex hormones in illegal products by validated liquid chromatography-high resolution mass spectrometry and liquid chromatography-tandem mass spectrometry methods

The consumption of food and drugs adulterated with female sex hormones can have an extremely adverse effect on human health. Therefore, developing appropriate monitoring methods for the identification of various exogenous female sex hormones is crucial for minimizing and eliminating the related health risks. Herein, 17 female hormones categorized into two groups: estrogen and progestin, were analyzed using reversed-phase liquid chromatography coupled to Orbitrap or triple quadrupole mass spectrometry. The fragmentation patterns for all compounds were discovered, and fragmented structures were also derived from them through liquid chromatography–high-resolution mass spectrometry followed by qualitative sample analysis. In addition, a quantitative analysis of 67 samples of illicit drugs and dietary supplements was performed using the validated liquid chromatography-tandem mass spectrometry method. Female hormone components were detected in two samples of an unauthorized injectable solution and a tablet-type drug. Medroxyprogesterone was detected in the samples in the range of 96.4–206 ng/g. Notably, eight components similar in structure to steroids were simultaneously detected as male sex hormones by confirming their fragmentation ion patterns using liquid chromatography–high-resolution mass spectrometry. The developed methods thus offer a dependable and practically applicable approach for the screening and detection of exogenous female sex hormones in real food and drug samples to ensure public health.     

White-beam X-ray diffraction and radiography studies on high-boron-containing borosilicate glass at high pressures

ABSTRACT

Multi-angle energy-dispersive X-ray diffraction studies and white-beam X-ray radiography were conducted with a cylindrically shaped (1?mm diameter and 0.7?mm high) high-boron-content borosilicate glass sample (17.6% B₂O₃) to a pressure of 13.7?GPa using a Paris-Edinburgh (PE) press at Beamline 16-BM-B, HPCAT of the Advanced Photon Source. The measured structure factor S(q) to large q?=?19 Å^?1 is used to determine information about the internuclear bond distances between various species of atoms within the glass sample. Sample pressure was determined with gold as a pressure standard. The sample height as measured by radiography showed an overall uniaxial compression of 22.5% at 13.7?GPa with 10.6% permanent compaction after decompression to ambient conditions. The reduced pair distribution function G(r) was extracted and Si–O, O–O and Si–Si bond distances were measured as a function of pressure. Raman spectroscopy of the pressure recovered sample as compared to starting material showed blue-shift and changes in intensity and widths of Raman bands associated with silicate and four-coordinated boron.     

Treadmill walking of the pneumatic biped Lucy: Walking at different speeds and step-lengths

Actuators with adaptable compliance are gaining interest in the field of legged robotics due to their capability to store motion energy and to exploit the natural dynamics of the system to reduce energy consumption while walking and running. To perform research on compliant actuators we have built the planar biped Lucy. The robot has six actuated joints, the ankle, knee and hip of both legs with each joint powered by two pleated pneumatic artificial muscles in an antagonistic setup. This makes it possible to control both the torque and the stiffness of the joint. Such compliant actuators are used in passive walkers to overcome friction when walking over level ground and to improve stability. Typically, this kind of robots is only designed to walk with a constant walking speed and step-length, determined by the mechanical design of the mechanism and the properties of the ground. In this paper, we show that by an appropriate control, the robot Lucy is able to walk at different speeds and step-lengths and that adding and releasing weights does not affect the stability of the robot. To perform these experiments, an automated treadmill was built Published in Prikladnaya Mekhanika, Vol. 44, No. 7, pp. 134–142, July 2008.     

Security control of interval type-2 fuzzy system with two-terminal deception attacks under premise mismatch

Nonlinear Dynamics - This paper focuses on security control of nonlinear networked control systems with parameter uncertainties. Interval type-2 T–S fuzzy model is used to represent the...