Protein Local Tertiary Structure Prediction by Super Granule Support Vector Machines with Chou-Fasman Parameter

Prediction of a protein's tertiary structure from its sequence information alone is considered a major task in modern computational biology.  In order to closer the gap between protein sequences to its tertiary structures, we discuss the correlation between protein sequence and local tertiary structure information in this paper.  The strategy we used in this work is predict small portions (local) of protein tertiary structure with high confidence from conserved protein sequences, which are called “protein sequence motifs”. 799 protein sequence motifs that transcend protein family boundaries were obtained from our previous work.  The prediction accuracy generated from the best group of protein sequence motifs always keep higher than 90% while more than 8% of the independent testing data segments are predicted. Since the most meaningful result published in latest publication is merely 70.02% accuracy under the coverage of 4.45%, the research results achieved in this paper are obviously outperformed. Besides, we also set up a stricter evaluation to our prediction to further understand the relation between protein sequence motifs and tertiary structure predictions.  The results suggest that the hidden sequence-to-structure relationship can be uncovered using the Super Granule SVM Model with the Chou-Fasman Parameter.  With the high local tertiary structure prediction accuracy provided in this article, the hidden relation between protein primary sequences and their 3D structure are uncovered considerably

Millimeter-Wave Metal Reflectarray Antennas with Sub-Wavelength Holes

Reflectarray antennas composed of rectangular grooves with sub-wavelength holes on a metal plate are designed for millimeter-wave regions. All depths of multiple grooves in the metal reflectarray are elaborately manipulated for a high-gain reflector. A sub-wavelength hole in each groove reduces the mass of the reflectarray antenna, which rarely affects the re-radiated millimeter-wave filed from the groove. In this paper, we have demonstrated light high-gain reflectarray antennas and achieved a 25%-light reflectarray antenna compared with a metal reflectarray without sub-wavelength holes. The designed reflectarray antenna operates within the 15% wide-band bandwidth at 3 dB for millimeter-wave band

Modulation-limited interference terahertz shapes via one-dimensional multilayer structures

We have found a modulation-limited behavior of interferometric THz spectra in the one-dimensional multilayer structures making up high/low refractive index material periods. These modulation-limited THz spectra are based on the fact that the degree of THz pulse broadening decreases with increasing the number of periods because some time-delayed and multiple reflected THz pulses are in-phase or out-of-phase. THz pulse broadening phenomenon can be expressed by a simple equation. The knowledge of spectral detail of THz pulses may improve the understanding and fabrication of THz multilayer structures, applicable for THz waveform synthesis

Investigation of THz birefringence measurement and calculation in Al_2O_3 and LiNbO_3

Based on the polarization-sensitive terahertz time-domain spectroscopy, we measured the birefringence for Al2O3 and LiNbO3 single crystals, which correspond to trigonal structures that have an uniaxial birefringence, in the THz frequency range of 0.25 to 1.4 THz. For more comprehensive understanding of the THz birefringence, the measured birefringence is compared with the results of ab initio calculations. The measured birefringence shows good agreement with the calculated value

High-Speed High-Resolution Terahertz Spectrometers

We demonstrate and characterize both asynchronous optical sampling terahertz time-domain spectroscopy (AOS THz-TDS) and terahertz frequency comb spectroscopy (TFCS) as high-speed, high-resolution terahertz (THz) spectroscopy. Two mode-locked femtosecond (fs) lasers with slightly different repetition frequencies are used without a mechanical delay stage to generate and detect THz pulses, respectively. Repetition frequencies of the two fs lasers are stabilized by use of two phase-locked loops sharing the same reference oscillator, respectively. For AOS THz-TDS, the difference frequency between the repetition frequencies is optimized and a signal-to-noise ratio is measured as a function of a measurement time. Spectra of THz frequency comb and its individual modes are measured from TFCS. A spectral resolution of 100 MHz is obtained in the both types of spectroscopy