Improved method for modulation transfer function measurement of Bayer color cameras.

Aiming at the difficulty of detecting the modulation transfer function (MTF) of Bayer color cameras during focusing, the traditional scheme is modified in this paper. First, through analysis, it is found that the MTF of the Bayer detector decreased substantially compared to the monochromatic detector, which was caused by the loss of a large amount of light from the Bayer detector. When the MTF is calculated for the color image after de-mosaicing, the degradation of image quality leads to the inability to obtain the full-frequency MTF curve. Therefore, this paper proposes a solution to detect the MTFs of the three primary colors in the Bayer image individually, and then weight the MTFs of each primary color to obtain the MTF of the color image based on the calibration results of the light source. Then, considering the steps of differentiation and Fourier transform in the slanted-edge method, this paper solves the problem of non-uniform sampling of edge spread function by using the modification of the slanted-edge method with non-uniform Fourier transform. Finally, the optimal imaging position of a certain type of Bayer color camera is determined using the methods proposed in this paper. Simulation and test results verify the effectiveness and accuracy of the methods in this paper.

Research on the Modulation Transfer Function Detection Method of a Bayer Filter Color Camera.

Bayer filter color cameras are more and more widely used in the field of aerospace remote sensing, but the Bayer filter causes great degradation in image quality; therefore, obtaining a means of achieving the high-precision measurement of the modulation transfer function (MTF) of Bayer filter color cameras is an urgent problem. In order to solve this problem, this paper develops a slanted-edge method via three steps: the detection of the slanted edge, the acquisition and processing of the edge spread function (ESF), and the acquisition and processing of the line spread function (LSF). A combination of the Canny operator and Hough transform is proposed for the detection of the slanted edge, which improves the fitting accuracy and anti-interference ability of the algorithm. Further, the Canny operator is improved by constructing an adaptive filter function and introducing the Otsu method, which can more effectively smooth the image and remove its false edges. A method of processing ESF data by combining cubic spline interpolation and Savitzky-Golay (SG) filtering is proposed, which reduces the effects of noise and the non-uniform sampling of ESF on MTF. A method of LSF processing using Gaussian function fitting is proposed to further reduce the effect of noise on MTF. The improved algorithm is verified by the MTF measurement test applied to a specific type of Bayer filter color space camera. The simulation and test results show that the improved slanted-edge method discussed in this paper has greater precision and a better anti-interference ability, and it can effectively solve the difficult problem associated with MTF detection in Bayer filter color space cameras.

Chicken-origin Cluster 3.2 Tembusu virus exhibits higher infectivity than duck-origin Cluster 2 Tembusu virus in chicks.

In 2020, a chicken-origin Cluster 3 Tembusu virus (TMUV) caused outbreaks of a disease characterized by egg-drop syndrome in laying hens in China. In the present study, a TMUV strain, TMUV-GX, was isolated from tissue samples of laying hens with egg drop syndrome in south China. Phylogenetic analysis grouped TMUV-GX into TMUV Cluster 3.2, which was distinct from the prevalent TMUV Cluster 2 in duck flocks. To study the infectivity and pathogenicity of TMUV-GX in chickens and ducks, 7 day-old specific pathogen-free (SPF) chicks and SPF ducklings were infected with the same dose of the TMUV-GX. As a comparison, the duck-origin Cluster 2 strain, TMUV-JM, infection groups were set up in chicks and ducklings. Compared with the low infectivity and pathogenicity of TMUV-JM in chicks, the chicken-origin TMUV-GX displayed high replication competence in multiple tissues and caused tissues histopathological damage. In addition, the replication competence of TMUV-GX in ducklings was comparable to that of TMUV-JM. Our study revealed chicken-origin Cluster 3.2 TMUV exhibits high infectivity in chicks and ducklings, and suggested that chicken-origin Cluster 3.2 TMUV possesses a biological basis for widespread infection of chickens and ducks.

Design, synthesis and biological evaluation of novel osimertinib derivatives as reversible EGFR kinase inhibitors.

A series of osimertinib derivatives without acrylamide groups were synthesized and their inhibitory rates against L858R/T790M/C797S mutated EGFR kinase and antiproliferation activities against non-small cell lung cancer cell lines (A549, H1975) were evaluated. The preferred compounds were selected and their in vitro inhibitory activities against various EGFR kinases (wild-type, L858R/T790M, L858R/T790M/C797S) and c-Met kinase were tested. Compound 9h showed remarkable inhibitory activity against the wild type (IC50 = 29 nM), L858R/T790M mutant type (IC50 = 10 nM) and L858R/T790M/C797S mutant type (IC50 = 242 nM) as reversible EGFR kinase inhibitor, which was selected to further perform the AO/EB staining assays, cell cycle distribution assays and wound-healing assays on A549 and/or H1975 cell lines. The results showed dose-dependent activities of the induction of cell apoptosis, G1/G0-phase arrestation and inhibition of migration. Compound 22a showed remarkable inhibitory activity against the L858R/T790M/C797S mutant EGFR kinase (IC50 = 137 nM), which was nearly three times compared to osimertinib (IC50 = 410 nM). It's worth noting that 22a exhibited excellent kinase selectivity against the L858R/T790M/C797S mutant EGFR kinase rather than the wild-type, which reached 5.4 times and far more than the 0.012 times of osimertinib. Additionally, molecular docking analyses were performed to explain the action modes between the compounds and the corresponding EGFR kinases. In conclusion, compounds 9h and 22a have been demonstrated as promising candidates and worth further study.

Using functional near-infrared spectroscopy (fNIRS) to detect the prefrontal cortical responses to deception under different motivations.

In this study, functional near-infrared spectroscopy (fNIRS) was adopted to investigate the prefrontal cortical responses to deception under different motivations. By using a feigned memory impairment paradigm, 19 healthy adults were asked to deceive under the two different motivations: to obtain rewards and to avoid punishments. Results indicated that when deceiving for obtaining rewards, there was greater neural activation in the right inferior frontal gyrus (IFG) than the control condition. When deceiving for avoiding punishments, there was greater activation in the right inferior frontal gyrus (IFG) and the left middle frontal gyrus (MFG) than the control condition. In addition, deceiving for avoiding punishments led to greater neural activation in the left MFG than when deceiving for obtaining rewards. Furthermore, the results showed a moderate hit rate in detecting deception under either motivation. These results demonstrated that deception with different motivations led to distinct responses in the prefrontal cortex. fNIRS could provide a useful technique for the detection of deception with strategy of feigning memory impairment under different motivations.

Stereoselective formation of eight-membered rings by radical cyclization of silylenedioxy-tethered bis-methacrylate derivatives.

Radical-initiated addition of CCl4, Cl3CBr, PhSH, and (TMS)3SiH to (bisisopropyl)silylenedioxy-tethered bis-methacrylate derivatives gives the corresponding eight-membered ring cyclic adducts stereoselectively. Hydrolysis of halo-substituted cyclic adducts with HCl in methanol affords the corresponding valerolactones, and the stereochemistry was determined by the X-ray crystallography on a dibromobenzoate derivative. DFT calculation on the eight-membered radical intermediate offers a plausible rationale for the stereoselectivity of the reaction.

Synthesis of 3-alkyl- or 3-allenyl-2-amidobenzofurans via electrophilic cyclization of o-anisole-substituted ynamides with carbocations.

A facile carbocation-induced electrophilic cyclization reaction has been developed for the synthesis of 3-alkyl- or 3-allenyl-2-amidobenzofurans from o-anisole-substituted ynamides and diarylmethanol or 1,1-diarylprop-2-yn-1-ol.

Synthesis of allenamides by Pd-catalyzed coupling of 3-alkoxycarbonyloxy ynamides or 1-alkoxycarbonyloxy allenamides with arylboronic acids.

An efficient palladium-catalyzed method is reported for the synthesis of multi-substituted allenamides by Suzuki-Miyaura cross-coupling reaction between easily prepared 3-alkoxycarbonyloxy ynamides or 1-alkoxycarbonyloxy allenamides and arylboronic acids.

Synthesis of δ-carbolines via a Pd-catalyzed sequential reaction from 2-iodoanilines and N-tosyl-enynamines.

A facile Pd-catalyzed sequential reaction has been developed for the synthesis of δ-carbolines from 2-iodoanilines and N-tosyl-enynamines. This protocol involves Larock heteroannulation/elimination/electrocyclization/oxidative aromatization cascade sequences and allows access to multisubstituted δ-carbolines in moderate to good yields.

Thorpe-Ingold effect in organosilicon chemistry.

Recent advances in the use of the concept of the Thorpe-Ingold effect to rationalise some synthetic chemistry involving organosilicon compounds and, in particular, the photophysical properties of certain dialkylsilylene spaced conjugated chromophores are discussed. The silicon moieties are considered to be insulating tetrahedral spacers in these silicon-containing copolymers. The substituents on silicon can readily be tuned and the steric environment of these substituents around the silicon may dictate the conformation (or helicity) of the copolymers and hence their photophysical properties. This substituent effect on silicon can be understood by the concept of the Thorpe-Ingold effect.

High-order statistical blind deconvolution of spectroscopic data with a Gauss-Newton algorithm.

The spectroscopic data recorded by a dispersion spectrophotometer are usually degraded by the response function of the instrument. To improve the resolving power, double or triple cascade spectrophotometers and narrow slits have been employed, but the total flux of the radiation available decreases accordingly, resulting in a lower signal-to-noise ratio (SNR) and a longer measurement time. However, the spectral resolution can be improved by mathematically removing the effect of the instrument response function. A high-order statistical Gauss-Newton algorithm is proposed to blindly deconvolve the measured spectroscopic data. The true spectrum and the instrument response function are estimated simultaneously. Experiments on artificial and real measured spectroscopic data demonstrate the feasibility of this method.

High-order cumulant-based blind deconvolution of Raman spectra.

The spectra recorded by a dispersion spectrophotometer are usually distorted by the response function of the instrument. To improve the resolving power, double or triple cascade spectrophotometers with narrow slits have been employed, but the total flux of the radiation available decreases accordingly, resulting in a low signal-to-noise ratio and a longer measuring time. The actual spectra can be restored approximately by mathematically removing the effects of the measuring instruments. Based on the Shalvi-Weinstein criterion, a (6, 2)-order normalized cumulant-based blind deconvolution algorithm for Raman spectral data is proposed. The actual spectral data and the unit-impulse response of the measuring instruments can be estimated simultaneously. By conducting experiments on real Raman spectra of some organic compounds, it is shown that this algorithm has a robust performance and fast convergence behavior and can improve the resolving power and correct the relative intensity distortion considerably.

(R)-mandelic acid (S)-alanine hemihydrate.

Crystals of the title complex, C(3)H(7)NO(2).C(8)H(8)O(3).0.5H(2)O, were obtained from an aqueous solution containing racemic mandelic acid and (S)-alanine. The unit cell includes two independent molecular complexes and one water molecule. The structure formed by (R)-mandelic acid and (S)-alanine in a 1:1 molar ratio shows the successful optical separation of racemic mandelic acid. Strong hydrogen bonding, with a rather short O...O separation of 2.494 (3) A, is observed between the carboxyl and carboxylate groups. A structural comparison suggests that the strong hydrogen bonding affects the neighbouring covalent bond.

(1R,3S)-Camphoramic acid.

The title chiral compound, 3-aminocarbonyl-1,2,2-trimethylcyclopentane-1-carboxylic acid, C(10)H(17)NO(3), was prepared from (1R,3S)-camphoric acid. The five-membered ring adopts a conformation which is intermediate between a twist and an envelope. Elongations of the C-C bonds and contractions of the C-C-C bond angles are observed within the five-membered ring. A (1)H NMR spectrum was recorded to assist in distinguishing the amide group from the carboxyl group.