As a strong reductant and highly active alkali, hydrazine (N2H4) has been widely used in chemical industry, pharmaceutical manufacturing and agricultural production. However, its high acute toxicity poses a threat to ecosystem and human health. In the present study, a ratiometric fluorescent probe for the detection of N2H4 was designed, utilizing dicyanoisophorone as the fluorescent group and 4-bromobutyryl moiety as the recognition site. 4-(2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-enyl) phenyl 4-brobutanoate (DDPB) was readily synthesized and could specially sense N2H4 via an intramolecular charge transfer (ICT) pathway. The cyclization cleavage reaction of N2H4 with a 4-bromobutyryl group released phenolic hydroxyl group and reversed the ICT process between hydroxy group and fluorophore, turning on the fluorescence in the DDPB-N2H4 complexes. DDPB exhibits a low cytotoxicity, reasonable cell permeability, a large Stokes shift (186 nm) and a low detection limit (86.3 nM). The quantitative determination of environmental water systems and the visualization fluorescence of DDPB test strips provides a strong evidence for the applications of DDPB. In addition, DDPB is suitable for the fluorescence imaging of exogenous N2H4 in HeLa cells and zebrafish.

The attachment and colonization process of microorganisms on a carrier is an interdisciplinary research field. Through a series of physical, chemical, and biological actions, the microorganisms can eventually reproduce on the carrier. This article introduces biofilm start-up and its applications, and explores the current issues to look forward to future development directions. Firstly, the mechanism of microbial film formation is analyzed from the microbial community colonization and reproduction process. Secondly, when analyzing the factors influencing microbial membrane formation, the effect of microbial properties (e.g., genes, proteins, lipids) and external conditions (i.e., carrier, operating environment, and regulation mechanism among microbial communities) were discussed in depth. Aimed at exploring the mechanisms and influencing factors of biofilm start-up, this article proposes the application measures to strengthen this process. Finally, the problems encountered and the future development direction of the technology are analyzed and prospected.

Two basic processes contribute to dispersal of soils pesticide : scattering, which is ensured by different modes of transfer, and degradation, which requires chemical or biochemical reactions that use soil micro-organisms. Last, pesticide or its alteration products can interact with soil constituents. | Deux processus fondamentaux contribuent à la dissipation d'un pesticide appliqué au sol. La dispersion, qui entraîne le produit et éventuellement ses dérivés hors du point d'application ou du volume de sol dans lequel il est recherché et la dégradation, qui assure la transformation de la molécule initiale d'une manière plus ou moins prononcée et pouvant aller jusqu'à sa minéralisation. La dispersion est assurée par différents modes de transfert (volatilisation, lixiviation-lessivage, entraînement par ruissellement, absorption par la plante), tandis que la dégradation fait intervenir des réactions chimiques ou biochimiques (photolyse, hydrolyse, ...) impliquant l'intervention des micro-organismes du sol. Enfin, le pesticide ou ses produits de transformation peuvent interagir avec les constituants du sol pour former des résidus "non extractibles". Ceux-ci sont alors soustraits au dosage par voie physico- chimique.

Two basic processes contribute to dispersal of soils pesticide : scattering, which is ensured by different modes of transfer, and degradation, which requires chemical or biochemical reactions that use soil micro-organisms. Last, pesticide or its alteration products can interact with soil constituents. | Deux processus fondamentaux contribuent à la dissipation d'un pesticide appliqué au sol. La dispersion, qui entraîne le produit et éventuellement ses dérivés hors du point d'application ou du volume de sol dans lequel il est recherché et la dégradation, qui assure la transformation de la molécule initiale d'une manière plus ou moins prononcée et pouvant aller jusqu'à sa minéralisation. La dispersion est assurée par différents modes de transfert (volatilisation, lixiviation-lessivage, entraînement par ruissellement, absorption par la plante), tandis que la dégradation fait intervenir des réactions chimiques ou biochimiques (photolyse, hydrolyse, ...) impliquant l'intervention des micro-organismes du sol. Enfin, le pesticide ou ses produits de transformation peuvent interagir avec les constituants du sol pour former des résidus "non extractibles". Ceux-ci sont alors soustraits au dosage par voie physico- chimique.