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Viral tracers are important tools for neuroanatomical mapping and genetic payload delivery. Genetically modified viruses allow for cell-type-specific targeting and overcome many limitations of non-viral tracers. Here, we summarize the viruses that have been developed for neural circuit mapping, and we provide a primer on currently applied anterograde and retrograde viral tracers with practical guidance on experimental uses. We also discuss and highlight key technical and conceptual considerations for developing new safer and more effective anterograde trans-synaptic viral vectors for neural circuit analysis in multiple species.

ObjectiveTo investigate the resistance to pyrethroids， beta-cyhalothrin and fenitrothion as well as the frequencies of kdr and ace⁃1 alleles in Anopheles sinensis from three geographical populations in Chongming District， Shanghai.MethodsThe contact tube method recommended by WHO was used to determine mosquito resistance. The frequencies of kdr and ace⁃1 alleles in adult mosquitoes were determined by PCR amplification. The correlation between the frequencies of kdr alleles and insecticide resistance was analyzed by linear regression method.ResultsThe mosquito population near natural reserve （NF） was sensitive to deltamethrin， and the mortality rate was 100.00% at 24 h. The mosquito population with intensive breeding farms （HX） showed resistance to deltamethrin and beta-cyhalothrin， and the 24 h mortality was 48.00 % and 57.50 %， respectively. The 24 h mortality rate of the mosquito population with urban-rural integration area （AS） with suspected resistance to deltamethrin and beta-cyhalothrin was 84.40% and 86.00%. The 24 h mortality rate to Fenitrothion was 55.67%. There were 3 mutations in kdr gene locus 1014， and 7 mutated genotypes were detected， mainly L1014/L1014F and L1014F/L1014F. The mutation frequency of kdr allele in HX population was the highest （52.68%）. There was one mutation at site 119 of ace⁃1 gene， and three genotypes were detected， most of which were G119S mutation. There was a significant negative correlation between the frequency of kdr resistance allele and the mortality rate of beta-cypermethrin in An.sinensis populations （r2=0.930，P=0.036）. There was a significant negative correlation between the frequency of ace⁃1 resistance allele and the mortality rate of fenitrothion in An. sinensis populations from four habitats （r2=0.996，P=0.038）.ConclusionThe mutation frequency of insecticide resistance allele is associated with the development of mosquito resistance level. Therefore， comprehensive monitoring of resistance levels of An.sinensis in Chongming area should be continued to provide a basis for local mosquito resistance management.

Ticks are the second most harmful infectious agent in the world after mosquitoes and can transmit a variety of pathogens. The surveillance of pathogen in ticks is one of the important means for the prevention and control of tick-borne diseases and tick-borne pathogens. This paper reviewed the literature published in the past two decades on the principles， advantages， disadvantages and applications of current tick pathogen detection technologies. The paper introduced the development and application of various PCR technologies， and looks forward to the future direction. Finally， it points out that metagenomics represented by high-throughput sequencing will become the mainstream development direction of pathogen detection technology in the future.

Cu/SSZ-13 is considered to be a promising material for NH3-SCR catalysts. However, in practical applications, Cu/SSZ-13 is inevitably exposed to alkali metal deposition. In this paper, Cu/SSZ-13 molecular sieve catalysts were prepared by the ion exchange method, catalysts with different degrees of alkali metal K/Na poisoning were prepared by the wet-impregnation method, and the SCR activity and N2 selectivity of fresh and poisoned catalysts were compared. The effects of alkali ion (Na+ and K+) poisoning on the comprehensive properties of Cu/SSZ-13 were studied. The distribution and quantity of Cu2+ active components in the catalyst before and after poisoning and the change of acidic sites were explored using NH3-TPO, NH3-TPD, H2-TPR, BET, and XRD. The characteristics of crystal structure, specific surface area, and pore structure revealed the influence of the loading of alkali metal K/Na on the adsorption performance, weakened redox characteristics, and a certain degree of structural damage of Cu/SSZ-13 molecular sieve catalyst. It explains that the reason for the decline in catalyst performance after poisoning is due to the decrease in the number of active sites caused by the ion-exchange between alkali metal ions and Cu2+ and H+, the increase of CuxOy species, the decrease of acidic sites, and pore blockage. This provides data support and theoretical basis for the design of highly resistant Cu/SSZ-13 catalysts. [ABSTRACT FROM AUTHOR]