Polarity-triggered anti-Kasha system for high-contrast cell imaging and classification

Kasha’s rule,which states that all exciton emissions occur from the lowest excited state and are independent of excitation energy,makes high-energy excitons difficult to use and severely hinders the widespread applications of organic photoluminescent materials in the real world.For decades,scientists have tried to break this rule to unleash the power of high-energy excitons,but only minimal progress has been achieved,with no rational guiding principles provided,and few applications developed.So far,breaking Kasha’s rule has remained a purely academic concept.In this paper,we introduce a design principle for a purely organic anti-Kasha system and synthesise a series of compounds based on the design rule.As predicted,these compounds all display evident S_(2) emissions in dilute solutions.In addition,we introduce a highly accurate(over 90%)convolutional neural network as an assistant for the classification of cells using anti-Kasha luminogens,thereby providing a new application direction for anti-Kasha systems.

Aggregation-induced conversion from TADF to phosphorescence of gold(I)complexes with millisecond lifetimes

Long-lived luminescent materials possess wide application prospects in various areas,but their constructions still face a huge challenge,especially the achievement in solution.Manipulating aggregate is an effective method to attain intriguing luminescence,thus it is expected to build long-lived materials in solution.In this work,a series of new gold(I)complexes were developed by employing unique carbazole and phosphine as the ligands,and these resulting systems exhibited rare long lifetimes of milliseconds in the aggregate state.It was well unveiled that these complexes emitted blue thermally activated delayed fluorescence(TADF)with the lifetimes of several microseconds in dilute solution;while orange-red phosphorescence with much longer lifetimes of several milliseconds were achieved in the aggregate state.To our knowledge,this is the first implementation of aggregation-induced conversion from TADF to phosphorescence.Based on their excellent luminescent properties,we successfully applied these complexes in cell imaging and inhibition of cancer cells.

ASBase:The universal database for aggregate science

This paper reports the first universal and versatile database on aggregate materials for the field of aggregate science research.At the current stage,the database(http://119.91.135.188:8080/)contains over 1000 entries of organic aggregate material systems(mainly luminescent systems at the current stage)with a unique data structure which is designed particularly for aggregate materials and containing the photophysics and physicochemical properties of the compounds in different statuses of aggregation,including dilute solution form,pristine solid-state,stable crystalline,and nanoaggregates formed in solvents.The web-based interface of the database provided functions to index,search,manipulate,fetch and deposit data entries.In addition,a background calculation service optimizes the chemical structure of new entries on different levels of accuracies.The database also provided background API for interactive developments of prediction or regression models based on machine-learning algorithms.

Dissecting the Genetic Basis of Grain Shape and Chalkiness Traits in Hybrid Rice Using Multiple Collaborative Populations

Dear Editor Through the efficient use of heterosis, hybrid rice varieties generally have higher grain yield potential than inbred varieties. With the significant advantage in grain yield, over the past 30 years approximately half of China＇s total rice-growing area is planted with rice hybrids. However, grain quality has now become one of the most important targets in hybrid rice breeding for meeting consumer demands. Grain shape and chalkiness are two important components of rice grain quality, in which slender grains （typically, grain length-to-width ratio 〉3） with low chatkiness are preferred by most consumers of hybrid rice.

Cytoplasmic and nuclear genome variations of rice hybrids and their parents inform the trajectory and strategy of hybrid rice breeding

The male sterility(MS)line is a prerequisite for efficient production of hybrid seeds in rice,a self-pollinating species.MS line breeding is pivotal for hybrid rice improvement.Understanding the historical breeding tra-jectory will help to improve hybrid rice breeding strategies.Maternally inherited cytoplasm is an appro-priate tool for phylogenetic reconstruction and pedigree tracing in rice hybrids.In this study,we analyzed the cytoplasmic genomes of 1495 elite hybrid rice varieties and identified five major types of cytoplasm,which correspond to different hybrid production systems.As the cytoplasm donors for hybrids,461 MS lines were also divided into five major types based on cytoplasmic and nuclear genomic architecture.Spe-cific core accessions cooperating with different fertility-associated genes drove the sequence divergence of MS lines.Dozens to hundreds of convergent and divergent selective sweeps spanning several agro-nomic trait-associated genes were identified among different types of MS lines.We further analyzed the cross patterns between different types of MS lines and their corresponding restorers.This study system-atically analyzed the cytoplasmic genomes of rice hybrids revealed their relationships with nuclear ge-nomes of MS lines,and illustrated the trajectory of hybrid rice breeding and the strategies for breeding different types of MS lines providing new insights for future improvement of hybrid rice.

A Simple Approach to Achieve Organic Radicals with Unusual Solid-State Emission and Persistent Stability

Sable organic radicals are promising materials for information storage,molecular magnetism,electronic devices,and biological probes.Many organic radicals have been prepared,but most are non-or weakly emissive and degrade easily upon photoexcitation.It remains challenging to produce stable and efficient luminescent radicals because of the absence of general guidelines for their synthesis.Herein,we present a photoactivation approach to generate a stable luminescent radical from tris(4-chlorophenyl)phosph ine(TCPP)with red emission in the crystal state.The mechanistic study suggests that the molecular symmetry breaking in the crystal causes changes of molecular conformation,redox properties,andmolecular packing that facilitates radical generation and stabilization.This design strategy demonstrates a straightforward approach to develop stable organic luminescent radicals that will open new doors to photoinduced luminescent radical materials.

Red-emitting salicylaldehyde Schiff base with AIE behaviour and large Stokes shift

Three salicylaldehyde Schiff base（SSB）, iso-PBP, PBP and EPB, were facilely synthesized and exhibited aggregation-induced emission. The introduction of C= N-N = C moiety in these SSB dyes largely extend the conjugation system and push their emission to yellow to red spectral region. These SSB dyes were negligibly fluorescent in dilute THF solution. In THF/water mixtures with high water fractions, they displayed strong yellow to red fluorescence（up to 617nm） and large Stokes shifts（up to 152 nm）. Single crystal analysis on EBP showed the longer emission of in aggregated state was attributed to the molecular packing effect as compared with that in dilute solution. The bio-imaging application indicated EBP could specifically accumulate in lipid droplets in living cells.