Residual Effect of Fipronil in Eriocheir sinensis

The residual effects of fipronil aqueous solutions(at mass concentrations of 10,30 and 50μg/L,respectively)on Eriocheir sinensis were investigated by the semi-static experiment method.The results showed that among the treatment groups with different mass concentrations,the high mass concentration group contained fipronil at a significantly higher content in the crab legs than the low-mass concentration group,and also a significantly higher content in the body than the low mass concentration group.There were no significant differences in the content of fipronil between different parts of E.sinensis.The trend of fipronil-enriched parts was from the legs to the body to the gonads.Fipronil residue in E.sinensis had no sex selectivity,but it enriched faster in female E.sinensis than males.This study provides a certain reference for dealing with related fishery pollution accidents.

探索Bi_(2)SeO_(5)的高介电性能:从块体到双层和单层

Bi_(2)SeO_(5)是一种具有优异电绝缘性能的范德华(vdW)层状介电材料,引起了极大关注.然而,目前关于Bi_(2)SeO_(5)的研究主要停留在实验层面,仍然缺乏对其原子级薄膜的介电性能的相关理论认识.本文通过第一性原理计算确定了Bi_(2)SeO_(5)的介电性能,发现其块体、双层和单层均具有超高平均介电常数(εr>20).研究表明,单层Bi_(2)SeO_(5)与双层Bi_(2)O_(2)Se之间的导带和价带能量偏移量均大于1 eV,表明单层Bi_(2)SeO_(5)依然可作为原子薄Bi_(2)O_(2)Se的良好介电层.此外,不同于h-BN或其他2D vdW绝缘体,Bi_(2)SeO_(5)的εr由其离子部分主导,且随着厚度的减小几乎保持不变.计算发现,单层Bi_(2)SeO_(5)的等效氧化层厚度可薄至0.3 n m,且单层Bi_(2)SeO_(5)在拉伸或压缩应变达到6%时均能保持高介电常数,这极大地促进了它与各种二维半导体的集成.本工作证明单层Bi_(2)SeO_(5)可以作为高性能二维电子器件良好的封装和介电层.

GaN nanowires/Si photocathodes for CO_(2) reduction towards solar fuels and chemicals: advances, challenges, and prospects

Photoelectrocatalytic(PEC)production of fuels and chemicals by using solar energy,water,and CO_(2) paves a promising avenue toward carbon neutrality.Over the past decades,for accelerating this process,a variety of photocathodes have been explored.Among them,the hybrid of GaN nanowires(NWs)and planar silicon has appeared as a disruptive platform for this grand topic,owing to their distinctive structural,optoelectronic,and catalytic properties.This review illustrates the most recent advances in GaN NWs/Si-based photocathodes for CO_(2) reduction reactions powered by simulated sunlight,beginning with a discussion of the critical requirements and fundamental challenges of PEC CO_(2) reduction.The characteristics of GaN NWs/Si are then discussed,showing its great potential in precisely controlling the behavior of photons,charges,and chemical species.As the focus of this review,the progress on the PEC CO_(2) reduction reactions toward different products over GaN NWs/Si-based photocathodes is highlighted.In the end,the challenges and prospects of GaN NWs/Si-based photocathodes for the practical synthesis of solarfuels and chemicals are proposed.

Active label distribution learning via kernel maximum mean discrepancy

Label distribution learning(LDL)is a new learning paradigm to deal with label ambiguity and many researches have achieved the prominent performances.Compared with traditional supervised learning scenarios,the annotation with label distribution is more expensive.Direct use of existing active learning(AL)approaches,which aim to reduce the annotation cost in traditional learning,may lead to the degradation of their performance.To deal with the problem of high annotation cost in LDL,we propose the active label distribution learning via kernel maximum mean discrepancy(ALDL-kMMD)method to tackle this crucial but rarely studied problem.ALDL-kMMD captures the structural information of both data and label,extracts the most representative instances from the unlabeled ones by incorporating the nonlinear model and marginal probability distribution matching.Besides,it is also able to markedly decrease the amount of queried unlabeled instances.Meanwhile,an effective solution is proposed for the original optimization problem of ALDL-kMMD by constructing auxiliary variables.The effectiveness of our method is validated with experiments on the real-world datasets.

Tumor microenvironment-responsive docetaxel-loaded micelle combats metastatic breast cancer

Efficient tumor-targeting drug delivery systems are urgently needed for treating metastatic breast cancer.In this work, a docetaxel(DTX)-loaded micelle(pDM) as the tumor-microenvironment-responsive delivery platform is developed. The micelle is composed of a pH-sensitive amphiphilic copolymer,poly((1,4-butanediol)-diacrylate-b-N,N-diisopropylethylenediamine)-polyethyleneimine(BD-PEI), and a matrix metalloproteinase(MMP)-responsive polymer, poly((1,4-butanediol)-diacrylate-b-N,N-diisopropy lethylenediamine)-peptide-polyethylene glycol(PEG)(BD-peptide-PEG). The PEG block of BD-peptidePEG will be split by MMPs at the tumor microenvironment, which leads to the change of the surface charge and particle size of the micelle to more positive and smaller one. Owing to this transformation and enhanced permeability and retention(EPR) effect, pDM delivers more DTX into tumor tissues and is internalized more efficiently by tumor cells than the non-MMP-sensitive micelles in the 4 T1 tumorbearing mice model. In addition, DTX is released in acidic endo/lysosomes due to the dissociation of the micelle, triggered by the protonation of the hydrophobic block of BD-PEI. As a result, the DTX-loaded micelle inhibits primary tumor growth and pulmonary metastasis effectively. Thus, this pH/MMP-dual-sensitive drug delivery system, which simultaneously attains three keypoints: prolonged circulation time, directional and efficient uptake into tumor cells, and speedy intracellular drug release, is a promising strategy for metastatic breast cancer therapy.

Near room-temperature ferromagnetism in air-stable twodimensional Cr_(1−x)Te grown by chemical vapor deposition

Identifying air-stable two-dimensional(2D)ferromagnetism with high Curie temperature(T_(c))is highly desirable for its potential applications in next-generation spintronics.However,most of the work reported so far mainly focuses on promoting one specific key factor of 2D ferromagnetism(T_(c)or air stability),rather than comprehensive promotion of both of them.Herein,ultrathin Cr_(1-x)Te crystals grown by chemical vapor deposition(CVD)show thickness-dependent T_(c)up to 285 K.The out-of-plane ferromagnetic order is well preserved down to atomically thin limit(2.0 nm),as evidenced by anomalous Hall effect observed in non-encapsulated samples.Besides,the CVD-grown Cr_(1-x)Te nanosheets present excellent ambient stability,with no apparent change in surface roughness or electrical transport properties after exposure to air for months.Our work provides an alternative platform for investigation of intrinsic 2D ferromagnetism and development of innovative spintronic devices.