Modulation of photonic skyrmions in a thin metal film structure.

Photonic skyrmions have been a hot topic in recent years. However, modulating the spin distributions of the skyrmions is still a challenging topic. In this paper, we investigate the detailed spin distributions of photonic skyrmions in thin metal film sandwiched by different dielectrics. We find that the ratios of different spin components can be adjusted by the thickness of the metal film, while the absolute value of total spin can be controlled by the frequency of the light source. Therefore, by choosing proper metal thickness in the preparation process and certain beam frequency in actual experiment, we can get the exact type of spin distribution we prefer. In addition, when the dielectric layers are arranged asymmetrically, the spin distributions can also be modulated significantly by adjustig the ratio of the dielectric constants of the upper and lower dielectric layers. Our results provide a new pathway for the modulation of photonic skyrmions.

Relationship between Human Papillomavirus Prevalence and DNA Damage in Cervical Cancer Population in Gansu Province, China.

OBJECTIVES: The aim of this study was to assess the possible reason of the high incidence and mortality of cervical cancer in Longnan, China. MATERIALS AND METHODS: 147 and 124 invasive squamous-cell carcinoma (SCC) samples from Longnan and different cities and districts of Gansu province were collected in the present study. All the samples were obtained from patients who underwent biopsies with colposcopy or advanced operations and were evaluated by experienced pathologists. HPV genotypes were examined with a validated HPV subtypes kit. The prevalence of HPV infection in SCC patients of China was analyzed by evidence-based medicine in the published literature. The markers of DNA damage response (DDR) - ATMpSer1981, H2AXp Ser139 (γH2AX), Chk2pThr68, and p53 - were analyzed by immunohistochemistry. RESULTS: HPV positivity, high-risk and multiple HPV positivity, and HPV58 infection were significantly higher in Longnan. Our results show that the prevalence of HPV infection in SCC patients of Longnan are consistent with the HPV prevalence in China. ATM, γH2AX, and p53 expressions in total and HPV+ samples were also higher in Longnan. CONCLUSIONS: HPV-related DDR activation may be one reason for the high incidence and mortality of Longnan cervical cancer.

Facile way to obtain multiple interface modes in a photonic crystal heterostructure.

A very facile way to obtain multiple interface modes in a one-dimensional photonic crystal heterostructure is proposed in this Letter. We found that the interface modes can be generated by introducing the interfaces, and the number of interface modes equals the number of introduced interfaces. All these interface modes originating from a different geometric Zak phase can create two band branches governed by the two different interfaces. We further find that the two band branches can be renormalized into one band branch with discrete energy levels in the form of sinusoidal function. We believe that these findings can be used to provide direct guidance for practical application and can also make the estimation of practical samples more convenient.

General way to obtain multiple defect modes in multiple photonic quantum-well structures.

We introduce a method to obtain and describe the multiple defect modes in the multiple photonic quantum-well structure [(AB)mC]n(AB)m. It is found that the relationship between structural parameters and defect modes can be obtained by analytically solving the dispersion relationship for the photonic crystal with its periodic unit [(AB)mC], and a laconic and unifying expression can be used to describe the energy levels of both the interface modes and defect modes. The internal mechanism to determine the related parameters is revealed. We believe that these findings can be used to provide direct guidance for practical application.

Effect of pump depletion on second harmonic generation in multiple quasi-phase-matching gratings.

Second harmonic generation (SHG) from the aperiodic optical superlattice (AOS) in considering the pump depletion is investigated. It is found the domain configuration designed in undepleted pump approximation (UPA) can also be used to achieve multiple wavelength SHGs with high enough conversion efficiency for an exact solution. The applicable scope of UPA was estimated by a relative tolerance based on the related SHG conversion efficiency calculated in UPA and an exact solution. Results reveal that the relative tolerance is solely determined by the conversion efficiency, and unrelated to the sample configuration, pump intensity, incidental wavelength and nonlinear media. A model to evaluate an exact solution is proposed, and it is suggested that the SHG conversion efficiency can be easily assessed by the developed model. These results can be used to provide direct guidance for practical application, and can also make the estimation of practical samples more convenient.

Analysis of gut microbiotal diversity in healthy young adults in Sunan County, Gansu Province, China.

Objective: To examine gut microbiotal diversity in the Han Chinese and Yugur populations of Sunan County, Gansu Province, living in the same environmental conditions, and to analyze possible causes of differences in diversity. Methods: We selected 28 people, ages 18-45 years old, all of whom were third-generation pure Yugur or Han Chinese from Sunan County. Fresh fecal samples were collected, and total bacterial deoxyribonucleic acid (DNA) was extracted. We performed 16S ribosomal ribonucleic acid (16S rRNA) high-throughput sequencing (HTS) and bioinformatics to study the relationships among between gut microbiota structure, genetics, and dietary habits in Yugur and Han Chinese subjects. Results: We found 350 differential operational taxonomic units (OTUs) in Han Chinese and Yugur gut microbiota, proving that gut microbiota differed between the two populations. That were less abundant among Yugurs than Han Chinese were Prevotella_9 and Alloprevotella. That were more abundant among Yugurs than Han Chinese were Anaerostipes and Christensenellaceae_R-7_group. And they were significantly associated with a high-calorie diet In addition. we found differences in predicted gut microbiota structural functions (The main functions were metabolic and genetic information) between the two populations. Conclusion: Yugur subjects demonstrated differences in gut microbiotal structure from Han Chinese subjects, and this difference influenced by dietary and may be influenced by genetic influences. This finding will provide a fundamental basis for further study of the relationships among gut microbiota, dietary factors, and disease in Sunan County.

Plasmonic band structures and optical properties of subwavelength metal/dielectric/metal Bragg waveguides.

In this paper, we applied the band structure theory to investigate the plasmonic band (PB) structures and optical properties of subwavelength metal/dielectric/metal Bragg waveguides in the near infrared range with either dielectric or geometric modulation. The Bloch wave vector, density of states, slowdown factor, propagation length and transmittance are calculated and analyzed. Both the modulations are in favor of manipulating surface-plasmon-polariton (SPP) waves. For the dielectric modulation, the PB structure is mainly formed by SPP modes and possesses a "regular pattern" in which the bands and gaps have a relatively even distribution. For the geometric modulation, due to the strong transverse scattering, the contributions of higher modes have to be considered and the gap widths have a significant increase compared to the dielectric modulation. A larger slowdown factor may emerge at the band edge; especially for the geometric modulation, the group velocity can be reduced to 1/100 of light, and negative group velocity is observed as well. While inside the bands, the slowdown factor is smaller and the bands are flat. The contribution of each eigenmode to the PB structure is analyzed.

MonoEF: Extrinsic Parameter Free Monocular 3D Object Detection.

Monocular 3D object detection is an important task in autonomous driving. It can be easily intractable where there exists ego-car pose change w.r.t. ground plane. This is common due to the slight fluctuation of road smoothness and slope. Due to the lack of insight in industrial application, existing methods on open datasets neglect the camera pose information, which inevitably results in the detector being susceptible to camera extrinsic parameters. The perturbation of objects is very popular in most autonomous driving cases for industrial products. To this end, we propose a novel method to capture camera pose to formulate the detector free from extrinsic perturbation. Specifically, the proposed framework predicts camera extrinsic parameters by detecting vanishing point and horizon change. A converter is designed to rectify perturbative features in the latent space. By doing so, our 3D detector works independent of the extrinsic parameter variations and produces accurate results in realistic cases, e.g., potholed and uneven roads, where almost all existing monocular detectors fail to handle. Experiments demonstrate our method yields the best performance compared with the other state-of-the-arts by a large margin on both KITTI 3D and nuScenes datasets.

Study on the Characteristics of Intestinal Flora Composition in Gastric Cancer Patients and Healthy People in the Qinghai-Tibet Plateau.

The aim of this study is to compare and analyze the structure and diversity of intestinal flora between gastric cancer patients and healthy people in the Qinghai-Tibet Plateau and to explore the characteristics of the intestinal flora composition in gastric cancer patients in the plateau area, and to determine the possible correlation between the intestinal flora and gastric cancer. Fresh feces from 22 cases of gastric cancer patients diagnosed in a tertiary hospital in Qinghai Province and 30 cases of healthy people during the same period were collected. The 52 subjects were undergone for 16S rDNA gene sequencing of intestinal bacteria to analyze and compare the diversity and compositional characteristics of intestinal flora. Analysis of the diversity of intestinal flora between the gastric cancer group and the healthy group was based on the Chao1 index of species richness, Shannon diversity index, and Simpson index. It showed that the gastric cancer group had no statistically difference from the healthy group (P > 0.05). In the Venn diagram, the number of OTU units shared by the gastric cancer group and the healthy group is 6997, and the number of unique OTU units in the healthy group is 2282, while the number of OTU units in the gastric cancer group is 896 and the difference is statistically significant (χ2 = 495.829), P < 0.000). Analysis of the composition and abundance distribution of intestinal flora showed that at the phylum level, there is no significant deference in abundance between the healthy group of Bacteroides and Firmicutes compared with the gastric cancer group (P > 0.05). However, there is a statistically significant difference in abundance between the healthy groups of Proteobacteria compared with the gastric cancer group (P < 0.05). At the genus level, the gastric cancer group of Prevotella_9 is significantly different from the healthy group (P < 0.05). Meanwhile, the gastric cancer group of Streptococcus and Lactobacillus are significantly different from the healthy group (P < 0.001). There are differences in the composition and abundance of intestinal flora between patients with gastric cancer and healthy people in plateau areas, suggesting that Proteobacteria, Prevotella_9, Streptococcus, and Lactobacillus have increased in the Qinghai-Tibet Plateau and becoming one of the factors related to the incidence of gastric cancer in the region.

Investigation of the wave behaviors inside a step-modulated subwavelength metal slit.

In this paper, we applied the modal expansion method (MEM) to investigate the wave behaviors inside a step-modulated subwavelength metal slit. The physical mechanism of the surface plasmon polariton (SPP) transmission is investigated in detail for slit structures with either dielectric or geometric modulation. The applicability of the effective index method is discussed. Moreover, as a special case of the geometric modulation, the evanescent-wave assisted transmission is demonstrated in a thin-modulated slit. We emphasize that a complete set is necessary in order to expand the wave functions in these kinds of structures. All the calculated results by the MEM are well retrieved by the finite-difference time-domain calculation.

The mechanism of the polarization dependence of the optical transmission in subwavelength metal hole arrays.

We investigate the mechanism of extraordinary optical transmission in subwavelength metal hole arrays. Experimental results for the arrays consisting of square or rectangular holes are well explained by the dependence of transmission strength on the polarization direction of the incident light. This polarization dependence occurs in each single hole. For a hole array, there is in addition an interplay between the adjacent holes which is caused by the transverse magnetic field of surface plasmon polaritons on the metal film surfaces. Based on the detailed study of a single-hole and two-hole structures, a simple method to calculate the total transmissivity of hole arrays is proposed.

[Synthesis of thienopyridine derivatives and its anti-platelet activity in vivo].

To explore novel ADP receptor inhibitors with anti-thrombotic activity, eighteen compounds were synthesized and their structures were confirmed by 1H NMR and MS. The results showed that the activity of compound C1 was superior to ticlopidine in platelet aggregation inhibition tests in vivo and worthy for further investigation. Compounds A4, B2, C4 and C7 possessed moderate platelet aggregation inhibitory activities.

[Transmission efficiency analysis of near-field fiber probe using FDTD simulation].

A fiber probe is the key component of near-field optical technology which is widely used in high resolution imaging, spectroscopy detection and nano processing. How to improve the transmission efficiency of the fiber probe is a very important problem in the application of near-field optical technology. Based on the results of 3D-FDTD computation, the dependence of the transmission efficiency on the cone angle, the aperture diameter, the wavelength and the thickness of metal cladding is revealed. The authors have also made a comparison between naked probe and the probe with metal cladding in terms of transmission efficiency and spatial resolution. In addition, the authors have discovered the fluctuation phenomena of transmission efficiency as the wavelength of incident laser increases.

Tunable multichannel Photonic spin Hall effect in metal-dielectric-metal waveguide.

The discovery of Photonic spin Hall effect (PSHE) on surface plasmon polaritons (SPPs) is an important progress in photonics. In this paper, a method of realizing multi-channel PSHE in two-dimensional metal-air-metal waveguide is proposed. By modulating the phase difference [Formula: see text] and polar angle [Formula: see text] of the dipole source, the SPP can propagate along a specific channel. We further prove that PSHE results from the component wave interference theory. We believe that our findings will rich the application of SPPs in optical devices.

Unidirectional propagation of the Bloch surface wave excited by the spinning magnetic dipole in two-dimensional photonic crystal slab.

The photonic spin Hall effect (PSHE) can be realized in a photonic crystal (PC) slab, that is, the unidirectional Bloch surface wave can propagate along the surface of the PC slab under the excitation of elliptical polarized magnetic dipole. It is further proved that PSHE is caused by the interference of the component surface waves excited by the different components of the incident light, which is the so called component wave interference (CWI) theory. In addition, we also find that the spin of the surface wave oscillates periodically in space, and the oscillation period is a unit cell. In a unit cell, the average spin keeps the spin orbit locked. The results show that the spin separation can also be modulated by the position and the polarization state of the magnetic dipole.

Ketoconazole pretreatment ameliorates carbon tetrachloride-induced acute liver injury in rats by suppressing inflammation and oxidative stress.

Several studies have demonstrated the chemopreventive role of ketoconazole in animal models of liver injury. However, the underlying molecular mechanisms of this hepatoprotective effect are poorly understood. The present study assessed the potential of ketoconazole to enhance resistance to carbon tetrachloride-induced hepatotoxicity in vivo in a rat model. Ketoconazole pretreatment adult male rats were intraperitoneally injected with carbon tetrachloride for 24 hr and various hepatic parameters were analyzed. We observed decreased serum transaminases activity, reduced nuclear RelA/p65 expression, and suppressed production of pro-inflammatory cytokines in the liver tissue. Histopathological examination demonstrated ketoconazole pretreatment to extensively prevent liver injury. In addition, it significantly increased nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) protein expression, glutathione (GSH) to oxidized glutathione (GSSG) ratio, and antioxidant enzymes gene expression. These results suggest that ketoconazole pretreatment ameliorates carbon tetrachloride-induced acute liver injury in rats, signifying its anti-inflammatory and antioxidant functions.

Astragaloside IV Protects Ethanol-Induced Gastric Mucosal Injury by Preventing Mitochondrial Oxidative Stress and the Activation of Mitochondrial Pathway Apoptosis in Rats.

Alcohol consumption affects gastric mucosa by multiple and complex mechanisms depending either by direct contact of ethanol or by indirect biological damage induced by its metabolite acetaldehyde. The present study aims at further investigating the mechanism of ethanol-induced gastric mucosa injury and the protective effect of astragaloside IV (AS-IV) in an aspect of mitochondrial oxidative stress and mitochondrial pathway of apoptosis. Using an array of experimental approaches, we have shown that the development of mitochondrial oxidative stress and associated apoptosis play crucial roles in the pathogenesis of gastric injury induced by ethanol. AS-IV inhibits mitochondrial oxidative stress by scavenging accumulation of malondialdehyde and decreasing the consumption of glutathione. AS-IV also prevents ethanol-induced apoptosis by modulating the activity of caspase-3 and caspase-9, the expression of Bax/Bcl-2, and the release of cytochrome C and apoptosis inducing factor. Moreover, AS-IV reduces ethanol-mediated activation of caspase-8 and breakage of Bid. This study thus indicates that AS-IV prevented ethanol-induced gastric damage by blocking activation of mitochondrial oxidative stress and mitochondrial pathway of apoptosis induced by ethanol in the gastric mucosa.

CCl4-Induced Liver Injury Was Ameliorated by Qi-Ge Decoction through the Antioxidant Pathway.

Qi-Ge decoction (QGD), which is derived from the Huangqi Gegen decoction, contains three traditional Chinese herbs: Astragalus membranaceus (Huangqi), Pueraria lobata (Gegen), and Citri Reticulatae Blanco Pericarpium (Chenpi). Gastric mucosal damage caused by ethanol was prevented and alleviated by QGD. However, the role of QGD in protecting the liver from toxins has not been reported. High-performance liquid chromatography with diode-array detection was used to qualitatively analyze QGD. Positive control (silymarin 100 mg/kg/day), QGD (20, 10, or 5 g/kg/day), and Nrf2 inhibitor brusatol (0.4 mg/kg/2 d) were administered to rats for 7 days, and then, liver injury was induced by injecting 2 mL/kg 25% CCl4. After 24 h, blood and liver were collected for analysis and evaluation. QGD was found to contain 12 main components including calycosin, puerarin, and hesperidin. QGD treatment significantly reduced liver damage and decreased serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities. QGD increased superoxide dismutase and catalase activities, and glutathione levels, but decreased malondialdehyde levels in livers from CCl4-treated rats. Compared to rats treated with CCl4 alone, after QGD administration, mRNA and protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 were increased, while those of Kelch-like ECH-related protein 1 (Keap1) and cytochrome P450 (CYP)2E1 were decreased. However, these improvements in QGD were reversed by brusatol. In conclusion, QGD can achieve its hepatoprotective effect through an antioxidant mechanism by activating the Nrf2 pathway.

External electric field control of THz pulse generation in ambient air.

A theoretical model has been proposed to describe the dependence of the THz wave generated in a laser-induced air plasma on the external electric field. Using this model we predict the following, (i) previously observed results show that the THz pulse enhances linearly with the increase of the external field; (ii) the THz pulse varies as a cosine function with the angle between the direction of the external electric field and the polarization of the incident exciting beam; (iii) and the amplitude is proportional to the square of the intensity of the incident pulse in a low energy region. These predictions are validated by our experiment.

Greatly enhanced light emission of MoS2 using photonic crystal heterojunction.

We present theoretical study on developing a one-dimensional (1D) photonic crystal heterojunction (h-PhC) that consists of a monolayer molybdenum disulfide (MoS2) structure. By employing the transfer matrix method, we obtained the analytical solution of the light absorption and emission of two-dimensional materials in 1D h-PhC. Simultaneously enhancing the light absorption and emission of the medium in multiple frequency ranges is easy as h-PhC has more modes of photon localization than the common photonic crystal. Our numerical results demonstrate that the proposed 1D h-PhC can simultaneously enhance the light absorption and emission of MoS2 and enhance the photoluminescence spectrum of MoS2 by 2-3 orders of magnitude.