Fluoride indicator that functions in mixed aqueous media: hydrogen bonding effects

A urea-based fluoride anion indicator, 3, that functions in mixed aqueous media is reported. Under these conditions, indicator 3 and the two control systems 1 and 2 are colorless. Addition of fluoride anions produces an easy-to-visualize colorimetric response (colorless to yellow) in the case of 3, but not 1 or 2 as the result of anion-induced Si–O bond cleavage. Most of the colorimetric response is believed to stem from an alteration in the hydrogen bonding network, rather than changes to the π-conjugation pathway per se.     

Transmission characteristics of electromagnetic waves in a semicircular plasma filament layer generated by a femtosecond laser

The transmission characteristics of electromagnetic (EM) waves in a semicircular plasma filament layer generated by a femtosecond laser were studied in a wide frequency band including radar waves. We have focussed on the influence of plasma parameters and filament arrangement based on the diffraction and superposition theory of EM waves on the transmittance. A numerical simulation model using the current density convolution finite-difference time-domain method was constructed in a semicircular multilayer filament structure, and the transmission characteristics of spherical EM waves were examined. The simulation results showed that in this semicircular structure, the transmittance was periodically changed at a frequency interval corresponding to the thickness of the filament channel. This phenomenon was more pronounced as the number of the filament layers increased. In the lower band (<30 GHz), there was little change in the transmittance according to layer-to-layer distance, but in the higher band (>30 GHz), it changed irregularly. On the contrary, for the electron number density, it changed regularly in the lower frequency and hardly changed in the higher frequency. When the number of layers was 3 or more, the transmittance became 0 at the centre of the channel, and a discontinuous interference pattern appeared more clearly as the frequency increased.     

Security enhancement for double-random phase encryption using orthogonally encoded image and electronically synthesized key data

We propose a security-enhanced double-random phase encryption(DRPE) scheme using orthogonally encoded image and electronically synthesized key data to cope with the security problem of DRPE technique caused by fixed double-random phase masks for encryption. In the proposed scheme, we adopt the electronically synthesized key to frequently update the phase mask using a spatial light modulator, and also employ the orthogonal encoding technique to encode the image and electronically synthesized key data, which can enhance the security of both data. We provide detailed procedures for encryption and decryption of the proposed scheme, and provide the simulation results to show the encryption effects of the proposed scheme.     

Non-Invasive Measurements of Thickness of Superconductor Films by Using Two-Resonant-Mode Rutile Resonator

The film thickness should be known for extrazting the intrinsic surface resistance from the effective surface resistance as measured by using the dielectric resonator method. Thicknesses of 70 nm to 360 nm are measured for YBa2 Cu3 O7-δ films in a non-invasive way by using the two-resonant-mode dielectric resonator （TDR） method. A futile resonator with the respective resonant frequencies of 15.25-15.61 GHz and 15.10-15.37 GHz for the TE021 and the TE012 modes is used for this purpose. Differences between the values as measured by using the TDR technique and those measured by using a step profilometer appear to be less than 3%, which is smaller than the previous value of 5% as measured by using a 8. 6 GHz single-resonance mode futile resonator [Lee et al. J. Korean Phys. Soc. 54（2009）1619]. Merits of using the TDR method are discussed.     

A SPECTROPHOTOMETRIC METHOD FOR CHLOROPLAST ATP SYNTHETASE ASSAY

Ultraviolet-B (UV-B,280–320 nm) irradiance was calculated for more than 1200 sites in Asia to characterize the spatial and temporal variation in the present UV-B climate for rice-growing regions. The analytical model of Green et al. (Photochem. Photobiol. 31 ,59–65, 1980) was used to compute UV-B irradiance for clear skies using satellite-observed ozone column thickness and local elevation data. Ground-based observations of cloud cover were then used to approximate the average effect of cloud cover on UV-B irradiance using the approach of Johnson et al. (Photochem. Photobiol. 23 ,179–188, 1976). Over the geographic range of rice cultivation, the maximum daily effective UV-B irradiance (UV-B_BE), when weighted according to a general plant action spectrum, was found to vary approx. 2.5-fold under both clear and cloudy sky conditions. Under clear skies, the timing of maximum solar UV-B_BE changed with latitude and varied from February-March near the equator to July-August at temperate locations. Cloud cover was found to alter the season of maximum UV-B_BE in many tropical regions, due to the pronounced monsoonal climate, but had little effect on UV-B seasonality at higher latitudes. Under a climate resulting from a doubling of atmospheric carbon dioxide, estimated UV-B using predicted cloud cover was found to change by up to 17% from present conditions in Thailand. Both latitudinal and seasonal variation in solar UV-B radiation may be important aspects of the UV-B climate for rice as cultivars differ in sensitivity to UV-B and are grown under diverse conditions and locations.     

CRFalign: A Sequence-Structure Alignment of Proteins Based on a Combination of HMM-HMM Comparison and Conditional Random Fields

Sequence–structure alignment for protein sequences is an important task for the template-based modeling of 3D structures of proteins. Building a reliable sequence–structure alignment is a challenging problem, especially for remote homologue target proteins. We built a method of sequence–structure alignment called CRFalign, which improves upon a base alignment model based on HMM-HMM comparison by employing pairwise conditional random fields in combination with nonlinear scoring functions of structural and sequence features. Nonlinear scoring part is implemented by a set of gradient boosted regression trees. In addition to sequence profile features, various position-dependent structural features are employed including secondary structures and solvent accessibilities. Training is performed on reference alignments at superfamily levels or twilight zone chosen from the SABmark benchmark set. We found that CRFalign method produces relative improvement in terms of average alignment accuracies for validation sets of SABmark benchmark. We also tested CRFalign on 51 sequence–structure pairs involving 15 FM target domains of CASP14, where we could see that CRFalign leads to an improvement in average modeling accuracies in these hard targets (TM-CRFalign ≃42.94%) compared with that of HHalign (TM-HHalign ≃39.05%) and also that of MRFalign (TM-MRFalign ≃36.93%). CRFalign was incorporated to our template search framework called CRFpred and was tested for a random target set of 300 target proteins consisting of Easy, Medium and Hard sets which showed a reasonable template search performance.     

Asymmetric Synthesis of Polyhydroxy Pyrrolidinonyl Nucleoside Analogues from Tartaric acid

Modificationofnucleosideisanefficientproceduretodevelopnewpotentagentsagainsthumantum0r0rvirusesl.Morechallengingistosynthesizenew0pticallyactivepolyhydroxynucleosideanalogues.Becauseofthelimitationofresources,itseemsaratherardu0usworkt0synthesizeopticallyactivecarbocyclicorotherheterocyclicnucleosideanalogueswithmorethantwochiralcarb0ns,thoughnaturalsugarsareavaiIablestartingmaterialstooxa-cyclicnucleosides,suchasfuran0sylorpyranosylones.Inthispaper,wereportanefficientandgeneralsyntheticroute…     

Photoreflectance characteristic about AlGaAs/GaAs heterostructure

We investigated the photoreflectance (PR) spectra of as-grown, etched AlGaAs/GaAs heterostructure sample. As etching time increases, the electric fields are reduced. And the surface and interface electric field calculated for the AlGaAs/GaAs sample, respectively.