Two Modes Near-zero Dispersion Flattened Photonic-crystal Fiber

Through massive computer simulation, a photonic-crystal fiber with seven air-hole defects as fiber core is proposed by using the software CUDOS based on the multipole method. In the given fiber parameters, the photonic-crystal fiber’s fundamental and second modes are dispersion flattened simultaneously in the communication O wave band, S wave band and C wave band. It is important in the relative application of multi-mode dispersion flattened photonic-crystal fiber

Anticancer effect of a combination of cisplatin and matrine on cervical cancer U14 cells and U14 tumor-bearing mice, and possible mechanism of action involved

Purpose: To investigate the anticancer effects of cisplatin (DDP) in combination with matrine on cervical cancer U14 cell tumor-bearing mice. Methods: The cell proliferation of cervical cancer U14 cells treated with DDP (25, 20, 15, 10 and 5 μg/mL); matrine (2.5, 2.0, 1.5, 1.0 and 0.5 mg/mL); or DDP (15 μg/mL) + matrine (2.5, 2.0, 1.5, 1.0 and 0.5 mg/mL) was determined with MTT assay. The anticancer effect of DDP + matrine in U14 tumor-bearing mice was also investigated, based on expression of tumor suppressor lung cancer 1 (TSLC1) using quantitative real time-polymerase chain reaction (qRT-PCR) and immunohistochemistry. Results: The inhibition of proliferation of U14 cells ranged from 26.68–70.25, 10.20–61.73, and 51.89–89.75 % for DDP, matrine and DDP + matrine, respectively. In mice with U14 solid tumors, the DDP group had 12.3 % weight loss (p < 0.05). Treatment with DDP, matrine, and DDP + matrine reduced tumor growth by 64.56, 42.22–56.67, and 67.78–81.11 %, respectively (p < 0.01). Results from RT-qPCR and immunohistochemistry showed corresponding increases in expression levels of TSLC1. Conclusion: These results indicate that the anticancer activity of DDP + matrine is higher than that of a single treatment with either DPP or matrine. The likely mechanism of action might be related to promotion of TSLC1 expression. This finding provides a potential strategy for the management of cervical cancer

A comparative study of iron and temperature interactive effects on diatoms and Phaeocystis antarctica from the Ross Sea, Antarctica

In the future, temperature and iron availability are predicted to change in the coastal polynyas of Antarctica, which are the most biologically productive regions of the Southern Ocean. We examined the individual and combined effects of iron addition (+500 nM) and temperature increase (4°C) on Phaeocystis antarctica and several dominant diatom species isolated from the McMurdo Sound sector of the Ross Sea. Iron addition increased growth, carbon fixation, iron uptake rates, cellular carbon quota, and cell size of almost all tested species, while temperature increase only affected certain species. Concurrent increases in temperature and iron synergistically stimulated the growth rates of some species, particularly Pseudo-nitzschia subcurvata. The diversified responses of these phytoplankton to iron and temperature may help explain the current spatial and temporal distributions of diatoms and prymnesiophytes in the Ross Sea. In the future, potential temperature and iron increases may promote the growth of the diatoms Chaetoceros sp., Fragilariopsis cylindrus, and especially P. subcurvata. In contrast, growth rates of P. antarctica did not increase at higher temperatures, suggesting that a shift in community composition toward diatoms may occur under warmer conditions in this biologically and biogeochemically important Southern Ocean polynya region

Treatment of mild and moderate congenital ptosis via the levator imbrication technique

Background: To correct mild and moderate congenital ptosis, traditional surgical techniques usually include dissection of the Müller’s muscle. Meanwhile, both the levator palpebrae superioris and the Müller’s muscle play a synergistic role to elevate the upper eyelid. Thus, to protect the Müller muscle and minimize injury, we developed and applied a levator imbrication technique in patients with mild and moderate congenital ptosis and followed it up to evaluate its clinical efficacy. Methods: This retrospective case series included 53 patients with mild and moderate congenital ptosis, all of whom had undergone ptosis correction using the levator imbrication technique at the Plastic and Aesthetic Department of the Second Affiliated Hospital of Zhengzhou University between June 2018 and June 2020. The outcomes of correction, upper eyelid appearance, and operative complications were observed and analyzed. The postoperative follow-up was 3–12 months. Results: Fifty cases of ptosis were fully corrected, and the bilateral double eyelids were smooth and natural. The eyelids of 20 patients were incompletely closed immediately after the operation but were able to close spontaneously within 2 weeks. No serious complications such as exposure keratitis were reported. Three patients with undercorrection underwent reoperation 3 months after the first operation, and ptosis was corrected. Conclusion: The levator imbrication technique for mild and moderate congenital ptosis is simple to perform and shortens the operation time with less damage, stable postoperative outcomes, and no long-term complications

Does Social Capital Benefit the Improvement of Rural Households’ Sustainable Livelihood Ability? Based on the Survey Data of Jiangxi Province, China

This article examines the influence of social capital on the sustainable livelihood ability of rural households who are out of poverty, in order to promote the sustainable development of their livelihood. Based on the survey data of 371 out-of-poverty households in rural Jiangxi, we analyzed the relationship between social capital and households’ sustainable livelihood ability using “Ordinary Least Square (OLS) + robust standard error” regression models and quantile regression models. Households’ social capital was measured from the following three dimensions: social network, social participation, and social trust. The benchmark regression models showed that social capital index, social network, and social participation all had a significant positive effect on the sustainable livelihood ability of out-of-poverty households. However, the impact of social trust on sustainable livelihood ability was not significant. In addition, the quantile regression analysis results showed that social capital index, social network, social participation, and social trust all contributed the most to households with a low sustainable livelihood ability. Therefore, it is suggested to improve the social capital accumulation of out-of-poverty households from multiple dimensions, so as to enhance the sustainable livelihood ability of households and consolidate poverty-alleviation achievements

A Review of the Design and Control of Free-Piston Linear Generator

The Free-piston linear generator (FPLG) is a novel energy converter which can generate electrical energy and is regarded as a potential technology for solving the restriction of the short driving range of electric vehicles. Getting rid of the crank and flywheel mechanism, FPLG obtains some advantages of a variable compression ratio, compact size, and highly-efficient power generation. Linear electric machine (LEM) design and piston motion control are two key technologies of FPLG. However, they are currently the main obstacles to the favorable performance of FPLG. LEM being used to drive the piston motion or generate electric energy is an integrated design including a motor/generator. Various types of LEMs are investigated, and suitable application scenarios based on advantages and disadvantages are discussed. The FPLG’s controller is used to ensure stable operation and highly-efficient output. However, cycle-to-cycle variations of the combustion process and motor/generator switching make it difficult to improve the performance of the piston motion control. Comments on the advantages and disadvantages of different piston motion control methods are also given in this paper

Self-Assisted First-Fix Method for A-BDS Receivers with Medium- and Long-Term Ephemeris Extension

As a sensor for standalone position and velocity determination, the BeiDou Navigation Satellite System (BDS) receiver is becoming an important part of the intelligent logistics systems under rapid development in China. The applications in the mass market urgently require the BDS receivers to improve the performance of such functions, that is, shorter Time to First Fix (TTFF) and faster navigation signal acquisition speed with Ephemeris Extension (EE) in standalone mode. As a practical way to improve such functions of the Assisted BDS (A-BDS) receivers without the need for specialized hardware support, a Self-Assisted First-Fix (SAFF) method with medium- and long-term EE is proposed in this paper. In this SAFF method, the dynamic Medium- and Long-Term Orbit Prediction (MLTOP) method, which uses the historical broadcast ephemeris data with the optimal configuration of the dynamic models and orbit fitting time interval, is utilized to generate the extended ephemeris. To demonstrate the performance of the MLTOP method used in the SAFF method, a suit of tests, which were based on the real data of broadcast ephemeris and precise ephemeris, were carried out. In terms of the positioning accuracy, the overall performance of the SAFF method is illustrated. Based on the characteristics of the medium- and long-term EE, the simulation tests for the SAFF method were conducted. Results show that, for the SAFF method with medium- and long-term EE of the BeiDou MEO/IGSO satellites, the horizontal positioning accuracy is about 12 meters, and the overall positioning accuracy is about 25 meters. The results also indicate that, for the BeiDou satellites with different orbit types, the optimal configurations of the MLTOP method are different

A Review on Disturbance Analysis and Suppression for Permanent Magnet Linear Synchronous Motor

In high-end testing and manufacturing equipment, a trend exists whereby the traditional servo feed system with a ball screw and rotary motor will gradually be replaced by a direct drive system. The precision motion system driven by a permanent magnet linear synchronous motor (PMLSM) offers several advantages, including high speed, high acceleration, and high positioning accuracy. However, the operating precision of the feed device will be affected by the PMLSM robustness to nonlinear and uncertain disturbances, such as cogging force, friction, thermal effects, residual vibration, and load disturbance. The aim of this paper was to provide a survey on disturbance analysis and suppression approaches to improve the dynamic performance of PMLSM motion systems. First, the origin and inhibition methods of thrust ripple and friction are presented. Second, the mechanisms, modeling approaches, and mitigation measures of thermal effects are introduced. Additionally, the residual vibration characteristics and suppression methods are discussed. Finally, disturbance observers of periodic and aperiodic loads are introduced. These suppression methods from structural design and control compensation are then discussed in order to improve the dynamic response and steady-state accuracy of PMLSM

Evaluation of conditioned Latin hypercube sampling for soil mapping based on a machine learning method

Sampling design plays an important role in soil survey and soil mapping. Conditioned Latin hypercube sampling (cLHS) has been proven as an efficient sampling strategy and used widely in digital soil mapping. cLHS samples are randomly selected in each stratum of environmental variables, thus the produced sample sets can vary significantly at different runs with the same sample size. Although variation of mapping accuracies caused by the randomness of cLHS has been realized and qualitatively mentioned in past studies. However, how the randomness of cLHS could quantitatively influence mapping accuracy has rarely been examined. In this study, we conducted experiments to examine how the sample randomness quantitatively influence soil mapping accuracy with different sample sizes, and analyzed the possible reasons from a pedogenesis perspective. The results showed that the largest range of mapping accuracies of 500 repeats was 39.5% at a sample density of 2.59 point/km2, while the smallest range was 7.3% at the maximum sample size with a sample density of 32.47 point/km2. The sample density for satisfactory prediction accuracies in our study area was at least 10.06 Point/km2. The results showed that both the allocation of sample points to each soil series and the typicality of sample points played important roles in mapping accuracies. But the deep reasons causing the unstable performance of cLHS at small sample sizes were the imbalanced class distribution of soil series and the overlap between soil series in the distribution of environmental covariates. Researchers need to be cautious about the output when applying cLHS with small sampling densities. Some effective approaches to address this issue include increasing the sample size, checking the sample allocations of a cLHS design with the assistance of legacy soil maps, or adding the legacy soil map as a variable during sampling design. When the sampling resources and legacy soil maps are limited for an area, fuzzy k-means clustering sampling could be a potential alternative. This study provides useful references for better understanding the uncertainty of cLHS when the sample density is small and selecting alternative sampling methods accordingly