Third-order nonlinear wavelength conversion in chalcogenide glass waveguides towards mid-infrared photonics

The increasing demand in spectroscopy and sensing calls for infrared(mid-IR)light sources.Here,we theoretically investigate nonlinear wavelength conversion of Ge_(28)Sb_(12)Se_(60)chalcogenide glass waveguide in the mid-IR spectral regime.With waveguide dispersion engineering,we predict generation of over an octave wavelength(2.8μm-5.9μm)tuning range Raman soliton self-frequency shift,over 2.5 octaves wavelength cover range supercontinuum(1.2μm-8.0μm),as well as single soliton Kerr comb generated in suspended Ge_(28)Sb_(12)Se_(60)waveguide.Our findings evidenced that Ge_(28)Sb_(12)Se_(60)chalcogenide glass waveguides can simultaneously satisfy the generation of Raman soliton self-frequency shift,supercontinuum spectrum,and Kerr frequency comb generation through dispersion engineering towards mid-IR on chip.

Association between Exposure of Rare Earth Elements and Outcomes of In Vitro Fertilization-Embryo Transfer in Beijing

Objective The study aimed to investigate the impact of rare earth elements(REEs)exposure on pregnancy outcomes of in vitro fertilization-embryo transfer(IVF-ET)by analyzing samples from spouses.Methods A total of 141 couples were included.Blood and follicular fluid from the wives and semen plasma from the husbands,were analyzed for REEs using inductively coupled plasma mass spectrometry(ICP-MS).Spearman's correlation coefficients and the Mann–Whitney U test were used to assess correlations and compare REE concentrations among three types of samples,respectively.Logistic models were utilized to estimate the individual REE effect on IVF-ET outcomes,while BKMR and WQS models explored the mixture of REE interaction effects on IVF-ET outcomes.Results Higher La concentration in semen(median 0.089 ng/mL,P=0.03)was associated with a lower fertilization rate.However,this effect was not observed after artificial selection intervention through intracytoplasmic sperm injection(ICSI)(P=0.27).In semen,the REEs mixture did not exhibit any significant association with clinical pregnancy.Conclusion Our study revealed a potential association between high La exposure in semen and a decline in fertilization rate,but not clinical pregnancy rate.This is the first to report REEs concentrations in follicular fluid with La,Ce,Pr,and Nd found at significantly lower concentrations than in serum,suggesting that these four REEs may not accumulate in the female reproductive system.However,at the current exposure levels,mixed REEs exposure did not exhibit reproductive toxicity.

10-GHz broadband optical frequency comb generation at 1550/1310 nm

The generation of high-repetition rate(frep≥10 GHz)ultra-broadband optical frequency combs(OFCs)at 1550 nm and 1310 nm is investigated by seeding two types of highly nonlinear fibers(HNLFs)with 10 GHz picosecond pulses at the pump wavelength of 1550 nm.When pumped near the zero dispersion wavelength(ZDW)in the normal dispersion region of a HNLF,10 GHz flat-topped OFC with 43 nm bandwidth within 5 dB power variation is generated by self-phase modulation(SPM)-based OFC spectral broadening at 26.5 dBm pump power,and 291 fs pulse trains with 10 GHz repetition rate are obtained at 18 dBm pump power without complicated pulse shaping methods.Furthermore,when pumped in the abnormal dispersion region of a HNLF,OFCs with dispersive waves around 1310 nm are studied using a common HNLF and fluorotellurite fibers,which maintain the good coherence of the pump light at 1550 nm.At the same time,sufficient tunability of the generated dispersive waves is achieved when tuning the pump power or ZDW.

A Research on the Path of Ideological and Political Education in Agricultural Colleges and Universities to Promote Rural Revitalization

Agricultural colleges and universities shoulder the arduous task of cultivating talents for rural revitalization,in which ideological and political education is the key link in talent training.Ideological and political education helps cultivate reliable talents for rural revitalization,stimulate the endogenous power of rural revitalization,and realize direct and indirect promotion of rural revitalization.However,there are still many issues in ideological and political education in terms of educational concept,educational content,and educational model.Hence,it is necessary to strengthen the role of ideological and political education in promoting rural revitalization by clarifying the goals and concepts of ideological and political education in agricultural colleges and universities,strengthening the cultivation of students’awareness of rural revitalization services,and innovating ideological and political education models.

Application of polygene polymerization for insect-resistant poplar breeding

A major goal of poplar breeding is to obtain new insect-resistant poplar varieties through genetic engineering.However,engineering poplars with only a single insect-resistant gene has limitations,such as narrow insecticidal bands and the rapid development of insect tolerance to the gene.To expand insecticidal bands,delay the development of insect tolerance,and improve the insect resistance of transgenic poplars,polygene polymerization is increasingly being applied to cultivate insect-resistant poplars.In the present study,we discuss polygene polymerization,applications of the polygene combination strategy,the current state of research on transgenic poplar with multiple insect-resistant genes,including existing problems,and future research directions.We provide reference data to aid the cultivation and utilization of new polygenic insect-resistant poplar varieties.

Nanomotor-based H_(2)S donor with mitochondrial targeting function for treatment of Parkinson’s disease

Reduction of endogenous hydrogen sulfide(H_(2)S)is considered to have an important impact on the progress of Parkinson’s disease(PD),thus exogenous H_(2)S supplementation is expected to become one of the key means to treat PD.However,at present,it is difficult for H_(2)S donors to effectively penetrate the blood brain barrier(BBB),selectively release H_(2)S in brain,and effectively target the mitochondria of neuron cells.Herein,we report a kind of nanomotor-based H_(2)S donor,which is obtained by free radical polymerization reaction between L-cysteine derivative modified-polyethylene glycol(PEG-Cys)and 2-methacryloyloxyethyl phosphorylcholine(MPC).This kind of H_(2)S donor can not only effectively break through BBB,but also be specifically catalyzed by cystathionineβ-synthase(CBS)in neurons of PD site in brain and 3-mercaptopyruvate sulfurtransferase(3-MST)in mitochondria to produce H_(2)S,endowing it with chemotaxis/motion ability.Moreover,the unique chemotaxis effect of nanomotor can realize the purpose of precisely targeting brain and the mitochondria of damaged neuron cytopathic diseases.This kind of nanomotor-based H_(2)S donor is expected to enrich the current types of H_(2)S donors and provide new ideas for the treatment of PD.

枯草芽孢杆菌菌剂不同施用方式对甜瓜土壤微生物多样性及生长的影响

甜瓜连作种植和化学肥料过量施用造成了土壤微生态环境失衡、病害严重和产量降低等问题。施用枯草芽孢杆菌菌剂是改善土壤微生态环境、防治土传病害、促进植物生长的一项重要措施。文中以枯草芽孢杆菌为试验菌剂,分析菌剂不同施用方式对设施甜瓜土壤微生物多样性及生长的影响,采用稀释涂布平板方法测定土壤中可培养微生物的数量,采用Illumina Miseq测序技术测定土壤未培养微生物多样性,采用称重法测定甜瓜产量。结果表明,不同甜瓜生育时期,灌根、穴施和蘸根3种菌剂施用方式处理土壤可培养细菌的数量均显著高于对照,灌根、穴施和蘸根处理之间不存在显著差异;3个菌剂施用方式处理开花期土壤真菌数量显著低于对照,但是拉秧期土壤真菌数量差异不显著。比较3种菌剂施用处理中未培养微生物的多样性发现,细菌Shannon指数均高于常规施肥对照,Simpson指数低于对照;蘸根处理的真菌Shannon指数最低,Simpson指数最高。NMDS和聚类分析发现枯草芽孢杆菌菌剂蘸根施用处理对土壤中细菌和真菌菌群影响较大,均独立于一个分枝。微生物菌剂的施用使拟杆菌门(Bacteroidetes)的丰度显著降低,放线菌门(Actinobacteria)和酸杆菌门(Acidobacteria)的丰度显著升高,其中以蘸根处理变化最大。菌剂处理对真菌菌群的多样性影响较小,仅对壶菌门(Chytridiomycota)的丰度有显著影响。施用枯草芽孢杆菌菌剂可增加甜瓜的株高、茎粗、叶面积,蘸根处理的促长、增产效果最为显著。枯草芽孢杆菌菌剂作为一种新型环保肥料,具有增加土壤可培养微生物数量、提高土壤微生物多样性、促长增产的作用,该研究为枯草芽孢杆菌菌剂的合理施用提供了科学依据。

Effect and mechanism of ferulic acid inclusion complexes on tyramine production by Enterobacter hormaechei MW386398 in smoked horsemeat sausages

Ferulic acid inclusion complexes(FA-HP-β-CD)effects on tyramine accumulation and gene expression of Enterobacter hormaechei MW386398 in traditional smoked horsemeat sausages were studied.Reverse transcription-quantitative polymerase chain reaction(RT-qPCR)was used to identify the expression of tyrosine decarboxylase(TDC)clusters in the tyramine producing pathway.In addition,relevant parameters such as microbial growth,moisture content,pH,and tyramine accumulation in pure cultures and during fermentation of smoked horsemeat sausages were evaluated.Ferulic acid(FA)and FA-HP-β-CD inclusion complexes both significantly decreased tyramine accumulation,as well as significantly inhibited tyrosine decarboxylase(tdcA)and tyrosine/tyramine antiporter(tyrP)genes expression(p<0.05).Furthermore,FA and FA-HP-β-CD inclusion complexes both reduced the number of Enterobacteriaceae in smoked horsemeat sausages,but did not alter the main microbiota.However,FA-HP-β-CD inclusion complexes exhibited stronger ability in hindering TDC related gene expression,reducing tyramine accumulation and antibacterial properties.These results indicate that FA-HP-β-CD inclusion complexes are able to reduce tyramine accumulation in smoked horsemeat sausages by inhibiting Enterobacteriaceae growth and gene expression.