In maize, co-expression of GAT and GR79-EPSPS provides high glyphosate resistance, along with low glyphosate residues.

Herbicide tolerance has been the dominant trait introduced during the global commercialization of genetically modified (GM) crops. Herbicide-tolerant crops, especially glyphosate-resistant crops, offer great advantages for weed management; however, despite these benefits, glyphosate-resistant maize (Zea mays L.) has not yet been commercially deployed in China. To develop a new bio-breeding resource for glyphosate-resistant maize, we introduced a codon-optimized glyphosate N-acetyltransferase gene, gat, and the enolpyruvyl-shikimate-3-phosphate synthase gene, gr79-epsps, into the maize variety B104. We selected a genetically stable high glyphosate resistance (GR) transgenic event, designated GG2, from the transgenic maize population through screening with high doses of glyphosate. A molecular analysis demonstrated that single copy of gat and gr79-epsps were integrated into the maize genome, and these two genes were stably transcribed and translated. Field trials showed that the transgenic event GG2 could tolerate 9000 g acid equivalent (a.e.) glyphosate per ha with no effect on phenotype or yield. A gas chromatography-mass spectrometry (GC-MS) analysis revealed that, shortly after glyphosate application, the glyphosate (PMG) and aminomethylphosphonic acid (AMPA) residues in GG2 leaves decreased by more than 90% compared to their levels in HGK60 transgenic plants, which only harbored the epsps gene. Additionally, PMG and its metabolic residues (AMPA and N-acetyl-PMG) were not detected in the silage or seeds of GG2, even when far more than the recommended agricultural dose of glyphosate was applied. The co-expression of gat and gr79-epsps, therefore, confers GG2 with high GR and a low risk of herbicide residue accumulation, making this germplasm a valuable GR event in herbicide-tolerant maize breeding. Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-023-00114-8.

Research on the Integration of Cultural Tourism Industry Driven by Digital Economy in the Context of COVID-19-Based on the Data of 31 Chinese Provinces.

This article examines the impact of digital economy on the integration of China's cultural tourism industry in the context of COVID-19 by measuring the integration degree of cultural tourism industry as a substitute variable of cultural tourism integration. The empirical study found that the development of digital economy during the COVID-19 pandemic did promote the integration of China's cultural tourism industry, and compared with year 2019, the digital economy has strengthened the integration of cultural tourism industry. During the COVID-19 pandemic, the development of digital economy has promoted the integration of China's cultural tourism industry, and the positive effect of digital economy on the integration of China's cultural tourism industry has gradually strengthened compared to previous ones. The digital economy has played a mediating role in the impact of COVID-19 on the integration of China's cultural tourism industry. Therefore, China should formulate macropolicies and digital economy-related policies to strengthen the ability of digital economy to deal with risks and improve the digital system.

Multiband bonding/anti-boding interaction and selective electric field confinement in the complementary metamaterial.

We report the experimental and theoretical study on the complementary planar metamaterial with asymmetrical air nanorods. Three high-quality samples are fabricated by the focused ion beam technique. Multi-band Fano-like resonances and selective electric field confinement in the visible-near infrared range are presented and well explained by the bonding/anti-boding and coupled mode theories of plasmonic resonators.

Out-of-plane focusing and manipulation of terahertz beams based on a silicon/copper grating covered by monolayer graphene.

We report new models for out-of-plane focusing and manipulation of terahertz beams based on a silicon/copper grating covered by monolayer graphene. Dependences of focusing and manipulation of terahertz beams on the chemical potential and scattering rate of graphene are investigated. Based on the graphene/silicon grating model, we demonstrate that the focal distance and intensity are sensitively influenced by the chemical potential. Based on the graphene/copper grating model, we show how 2 to 1 and 3 to 1 modulation of terahertz beams can be efficiently realized through tuning the chemical potential of graphene. These tunable beam focusing and manipulation effects are well explained by the diffraction theory of optical images and the surface plasmon polariton theory of graphene. Our proposed devices are of compact structures, high electro-optical tunability and good repeatability, and they are expected to have prospective applications in terahertz communications, imaging, sensing, and so on.

Super resolution from pure/hybrid nanoscale solid immersion lenses under dark-field illumination.

We report a super-resolution strategy based on pure/hybrid nanoscale solid immersion lenses (n-SILs) under dark-field illumination. Dependences of the focusing performance of pure n-SILs on different diameters, locations, and substrates are investigated. Simulation results demonstrate a higher resolution (up to a 22.8% improvement) of pure n-SILs under dark-field illumination than convergent plane wave illumination. A hybrid n-SIL with a higher-index nanorod embedded into the n-SIL is proposed. Under dark-field illumination, the hybrid n-SIL can generate a near-field focal spot with a much higher resolution (~λ/8) that is beyond the Abbe diffraction limit in the nanorod. These results have potential applications in data storage, near-field mapping and spectra, and nanoscale lithography.

Accurate Modeling of Dark-Field Scattering Spectra of Plasmonic Nanostructures.

Dark-field microscopy is a widely used tool for measuring the optical resonance of plasmonic nanostructures. However, current numerical methods for simulating the dark-field scattering spectra were carried out with plane wave illumination either at normal incidence or at an oblique angle from one direction. In actual experiments, light is focused onto the sample through an annular ring within a range of glancing angles. In this paper, we present a theoretical model capable of accurately simulating the dark-field light source with an annular ring. Simulations correctly reproduce a counterintuitive blue shift in the scattering spectra from gold nanodisks with a diameter beyond 140 nm. We believe that our proposed simulation method can be potentially applied as a general tool capable of simulating the dark-field scattering spectra of plasmonic nanostructures as well as other dielectric nanostructures with sizes beyond the quasi-static limit.

Polarization-insensitive and broad-angle self-collimation in a two-dimensional photonic crystal with rectangular air holes.

In this paper, we have systematically investigated the polarization-insensitive and broad-angle self-collimation behavior in a square-lattice two-dimensional photonic crystal (PhC) with rectangular air holes. By analyzing the band structures and the corresponding equi-frequency contours (EFCs), it is found that such PhC can show special dispersion properties when the half-length L and half-width W of rectangular air holes are appropriately changed. First, compared with conventional square-lattice PhCs with circular or square air holes, such PhC is easier to support polarization-insensitive self-collimation (PISC) based on the EFCs for the second band. Meanwhile, the PISC behavior such as working frequency range and effective incident angle can be more flexibly adjusted by changing the structural parameters of rectangular air holes. Second, such PhC can show long flat EFCs for the TM-3 band. This is quite helpful for supporting broad-angle self-collimation. In particular, when L=0.5a and W/L=0.8, this PhC will degenerate to a one-dimensional grating PhC. It can show good all-angle self-collimation behavior with an improved relative bandwidth (about 19.98%) compared with previous works. It also presents advantages in practical applications due to a relatively convenient fabrication process.

Application of 3D-computed tomography angiography technology in large meningioma resection.

OBJECTIVE: To discuss the role of 3D-computed tomography angiography (3D-CTA) technology in reducing injuries of large meningioma surgery. METHODS: 3D-CTA preoperative examinations were done in 473 patients with large meningioma (simulated group). The images were analyzed by 3D post-processing workstation. By observing the major intracranial blood vessels, venous sinus, and the compression and invasion pattern in the nerve region, assessing risk level of the surgery, simulating the surgical procedures, the surgical removal plan, surgical routes and tumor blood-supplying artery embolisation plan were performed. Two hundred and fifty seven large meningioma patients who didn't underwent 3D-CTA preoperative examination served as control group. The incidence of postoperative complications, intraoperative blood transfusion and the operation time were compared between these two groups. RESULTS: Compared with the control group, the Simpson's grade I and II resection rate was 80.3% (380/473), similar with that of the control (81.3%, 209/257). The incidence of postoperative complications in 3D-CTA simulated group was 37.0% which was significantly lower than that (48.2%) of the control (P<0.01). The intraoperative blood supply for simulated group and the control was (523.4±208.1) mL and (592.0±263.3) mL, respectively, with significant difference between two groups (P<0.01). And the operation time [(314.8±106.3)] min was significantly lower in simulated group than that in the control [(358.4±147.9) min] (P<0.01). CONCLUSION: Application of 3D-CTA imaging technology in risk level assessment before large-scaled meningioma resection could assist in the rational planning of tumor resectin, surgical routes, and is helpful in reducing injuries and complications and enhancing the prognosis of the patients.

Dual-negative-refraction and imaging effects in normal two-dimensional photonic crystals with hexagonal lattices.

A novel dual-negative-refraction (DNR) effect is studied in two types of normal two-dimensional photonic crystals (2DPCs) with hexagonal lattices. Systematical analyses of the band structures and equifrequency surfaces indicate that the DNR may be realized when the overlapping second and third bands with relatively flat shapes and only a slight separation are available at some frequencies close to the band's peak of 2DPCs. Further simulations have not only confirmed the DNR and corresponding dual-imaging effects in normal 2DPCs with hexagonal lattices but also revealed some relative rules to the dual images. In particular, the thickness as well the cutoff value at terminations of PCs can strongly influence the performance of dual images and even determine whether the dual images would appear. Moreover, a relatively low working frequency is recommended to minimize the distortion degree of dual images.

Design and fabrication of rod-type two-dimensional photonic crystal slabs with large high-order bandgaps in near-infrared wavelengths.

We proposed a novel two-dimensional photonic crystal slab comprised of a number of silicon rods with different radii and locations in the square-lattice unit cell pattern. Such rod-type photonic crystal slabs were automatically optimized by the genetic algorithm and fabricated on the silicon-on-insulator wafer. In particular, the measured transmission spectra of the five-rods sample have shown a large accepted high-order bandgap between 1498 and 1648 nm (gap size is 9.54%). Based on the theories of multiple Bragg and Mie scattering effects, we have given a reasonable explanation to the large high-order bandgaps found in the present study.

Design and fabrication of high-efficiency photonic crystal power beam splitters.

Efficient beam splitters in a planar photonic crystal waveguide with corrugated terminators were designed, fabricated, and characterized. Experimental results showed that these beam splitters have high splitting efficiency and power intensity in the propagation direction, an achievement made possible through a design method employing a genetic algorithm-based optimization method. High-efficiency power beam splitters are useful components in integrated optics, and the design implemented here is particularly suited for integration with other optical components.

Genetic optimization of photonic crystal waveguide termination for both on-axis and off-axis highly efficient directional emission.

In this work, we use the finite-difference time-domain method in conjunction with a genetic algorithm (GA) to design a photonic crystal waveguide with gratinglike surface added for highly-efficient directional emission. By placing a detector at different locations in the output field, we have obtained both on-axis and off-axis highly-efficient directional emission designs with the help of GA. The interference of light emitted from the outlet of waveguide and surfaces modes in gratinglike surface is believed to account for the directional beaming effect in our designs.

Geometric and electronic properties of endohedral Si @ C74.

The generalized gradient approximation based on density functional theory is used to analyze the geometric and electronic properties of Si @ C(74). It is found that among the five possible optimized geometries of Si @ C(74), the most favorable endohedral site of Si atom is under the center of a pentagon ring on the sigma(h) plane, i.e., Si @ C(74)-5, which is different from the center stable site for Si in C(74) calculated by the semiempirical molecular orbital calculations and molecular mechanics calculations, and it is also different from the stable site, i.e., under a [6, 6] bond along the C(2) axis on the sigma(h) plane in C(74) for metal atoms Ba, Ca, and Eu. The deformation charge density on the sigma(h) plane reveals that the Si-C bonds in Si @ C(74)-5 have covalent character, while the Mulliken charge analysis together with a longer Si-C bond length reveals that the Si-C bonds in Si @ C(74)-5 have ionic character. Therefore, we infer that Si-C bonds in Si @ C(74)-5 contain both covalent and ionic characters.

Association of Fas-670 gene polymorphism with inflammatory bowel disease in Chinese patients.

AIM: Recent studies suggest that Fas-mediated apoptosis is involved in the pathogenesis of inflammatory bowel disease (IBD). It has been hypothesized that either increased apoptosis of intestinal epithelium or decreased apoptosis of lamina propria lymphocytes may induce inflammation of gut. The aim of this study was to determine whether the Fas gene promoter polymorphism at position-670 was associated with IBD in Chinese patients. METHODS: Fifty unrelated Chinese patients with IBD (38 patients with ulcerative colitis and 12 with Crohn's disease) and 124 healthy controls were genotyped for the Fas-670 polymorphism by PCR-restriction fragment length polymorphism method. The PCR product was digested by Mva I restriction enzyme. RESULTS: Distribution of the Fas-670 gene polymorphism was 33% for the AA genotype, 52% for the AG genotype and 15% for the GG genotype in 124 healthy subjects. In patients with IBD, 30% was for the AA genotype, 42% for the AG genotype and 28% for the GG genotype respectively. However, there was no significant difference in the genotype (P = 0.1498), allele frequencies (P = 0.3198) and carriage frequencies (P = 0.4133) between healthy controls and IBD patients. Furthermore, we did not find any difference between the left-sided colitis and total colitis (P = 0.8242). CONCLUSION: Fas-670 polymorphism is not associated with IBD in Chinese patients.