Enhancing the Photosensitivity of Hypocrellin A by Perylene Diimide Metallacage‑Based Host–Guest Complexation for Photodynamic Therapy

The development of supramolecular hosts which can efficiently encapsulate photosensitizers to improve the photodynamic efficacy holds great promise for cancer therapy.Here,we report two perylene diimide-based metallacages that can form stable host–guest complexes with planar conjugated molecules including polycyclic aromatic hydrocarbons and photosensitizers(hypocrellin A).Such host–guest complexation not only prevents the aggregation of photosensitizers in aqueous environments,but also offers fluorescence resonance energy transfer(FRET)from the metallacage to the photosensitizers to further improve the singlet oxygen generation(Φ_(Δ)=0.66).The complexes are further assembled with amphiphilic polymers,forming nanoparticles with improved stability for anticancer study.Both in vitro and in vivo studies indicate that the nanoparticles display excellent anticancer activities upon light irradiation,showing great potential for cancer photodynamic therapy.This study provides a straightforward and effective approach for enhancing the photosensitivity of conventional photosensitizers via host–guest complexation-based FRET,which will open a new avenue for host–guest chemistry-based supramolecular theranostics.

Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel

High-efficiency abrasive process with CBN grinding wheel is one of the important techniques of advanced manufacture. Combined with raw and finishing machining, it can attain high material removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high-efficiency abrasive machining technologies with CBN grinding wheel relate to high speed and super-high speed grinding, quick point-grinding, high efficiency deep-cut grinding, creep feed deep grinding, heavy-duty snagging and abrasive belt grinding were summarized. The efficiency and parameters range of these abrasive machining processes were compared. The key technologies of high efficiency abrasive machining, including grinding wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and workpiece and safety defended, as well as intelligent monitor and NC grinding were investigated. It is concluded that high efficiency abrasive machining is a promising technology in the future.

Highly emissive perylene diimide-based bowtie-shaped metallacycles

Metallacycles hold great promise for fluorescence-based sensing due to their synthetic advantages and unique physicochemical properties. However, it remains highly challenging to develop a versatile methodology for constructing highly emissive metallacycles with targeted functionalities and therefore soughtafter properties. Herein, we report a general strategy to construct a series of highly emissive perylene diimide-based metallacycles via the self-assembly of perylene diimide-based tetrapyridyl ligand with different dicarboxylic ligands featuring fixed angles and cis-Pt(PEt_(3))_(2)(OTf)_(2). Single crystal X-ray diffraction analyses verify the formation of bowtie-like metallacycles with two triangular cavities. Notably, the fluorescence quantum yields of most assemblies exceed 98%, amongst the highest values for metallacycles.Additionally, such metallacycles exhibit sensitive fluorescence responses toward picric acid with a detection limit of 2.8 × 10^(-6)mol/L. This study not only provides a rational strategy for preparing highly emissive bowtie-shaped metallacycles, but also sheds light on their usage in the detection of picric acid and associated compounds.

Global observation of urban expansion and land-cover dynamics usingsatellite big-data

Humans deeply influence the urbanizing of earth’s surface system in an exacerbating manner across space and time[1].Around the globe,urban land-use/cover changes reflect the intensities of human activities and land shifts from nature or semi-nature lands to man-made–dominated surfaces[2].

Luminescent Metallo-Supramolecular Polymers

Luminescent metallo-supramolecular polymers are a type of functional supramolecular architectures which integrates the advantages of emission,metal-coordination,supramolecular chemistry as well as polymeric properties to realize advanced functions.Due to the abundant stimuli-responsiveness of supramolecular assemblies and the light-emitting properties,they have been widely applied as chemo-sensors,light-emitting devices,contrast agents for bio-imaging,etc.In this review,we classify luminescent metallo-supramolecular polymers based on the types of species (lanthanides,organometallic compounds,oligomer or polymer-based ligands,small-molecule-based organic ligands) used to generate the luminescence and summarize recent developments of luminescent metallo-supramolecular polymers.We mainly focus on the functions and applications of luminescent metallo-supramolecular polymers and hope to give our reader a snapshot of research on luminescent metallo-supramolecular polymers and encourage more scientists to devote into this promising area.

Cultivated hawthorn(Crataegus pinnatifida var.major)genome sheds light on the evolution of Maleae(apple tribe)

Cultivated hawthorn(Crataegus pinnatifida var.major)is an important medicinal and edible plant with a long history of use for health protection in China.Herein,we provide a de novo chromosomelevel genome sequence of the hawthorn cultivar“Qiu Jinxing.”We assembled an 823.41 Mb genome encoding 40571 genes and further anchored the779.24 Mb sequence into 17 pseudo-chromosomes,which account for 94.64%of the assembled genome.Phylogenomic analyses revealed that cultivated hawthorn diverged from other species within the Maleae(apple tribe)at approximately 35.4 Mya.Notably,genes involved in the flavonoid and triterpenoid biosynthetic pathways have been significantly amplified in the hawthorn genome.In addition,our results indicated that the Maleae share a unique ancient tetraploidization event;however,no recent independent whole-genome duplication event was specifically detected in hawthorn.The amplification of non-specific long terminal repeat retrotransposons contributed the most to the expansion of the hawthorn genome.Furthermore,we identified two paleo-sub-genomes in extant species of Maleae and found that these two sub-genomes showed different rearrangement mechanisms.We also reconstructed the ancestral chromosomes of Rosaceae and discussed two possible paleopolyploid origin patterns(autopolyploidization or allopolyploidization)of Maleae.Overall,our study provides an improved context for understanding the evolution of Maleae species,and this new highquality reference genome provides a useful resource for the horticultural improvement of hawthorn.

Conformational effect on fluorescence emission of tetraphenylethylene-based metallacycles

Herein,we designed and constructed two metallacycles,1 and 2,to illustrate the conformational effect of isomeric AIE fluoropho res on the platfo rm of supramolecular coordination complexe s(SCCs).Specifically,the dangling phenyl rings in TPE units of the metallacycle 1 align completely outside the main cyclic structure,while in the metallacycle 2,these phenyl rings align half inside and half outside.The experimental results showed that two metallacycles exhibited different behaviors in terms of AIE fluorescence and chemical sensing,which could be attributed to the subtle structural difference of the TPE units.This work repre sents the unification of topics such as self-assembly,AIE,and chemical sensing,and further promotes the understanding for the structure-property relationship of isomeric AIE fluorophores.

Perylene Diimide-Based Multicomponent Metallacages as Photosensitizers for Visible Light-Driven Photocatalytic Oxidation Reaction

Self-assembled supramolecular structures with efficient singlet oxygen(1O2)-generation ability are expected to enable photocatalytic oxidation reactions.Herein,we use two photosensitizers,perylene diimide and benzothiadiazole derivative,as the boards to prepare two barrel-shaped metallacages viametal-coordination-driven self-assembly.

Ongoing Positive Selection Drives the Evolution of SARS-CoV-2 Genomes

SARS-CoV-2 is a new RNA virus affecting humans and spreads extensively throughout the world since its first outbreak in December,2019.Whether the transmissibility and pathogenicity of SARS-CoV-2 in humans after zoonotic transfer are actively evolving,and driven by adaptation to the new host and environments is still under debate.Understanding the evolutionary mechanism underlying epidemiological and pathological characteristics of COVID-19 is essential for predicting the epidemic trend,and providing guidance for disease control and treatments.Interrogating novel strategies for identifying natural selection using within-species polymorphisms and 3,674,076 SARSCoV-2 genome sequences of 169 countries as of December 30,2021,we demonstrate with population genetic evidence that during the course of SARS-CoV-2 pandemic in humans,1)SARS-CoV-2 genomes are overall conserved under purifying selection,especially for the 14 genes related to viral RNA replication,transcription,and assembly;2)ongoing positive selection is actively driving the evolution of 6 genes(e.g.,S,ORF3a,and N)that play critical roles in molecular processes involving pathogen–host interactions,including viral invasion into and egress from host cells,and viral inhibition and evasion of host immune response,possibly leading to high transmissibility and mild symptom in SARS-CoV-2 evolution.According to an established haplotype phylogenetic relationship of 138 viral clusters,a spatial and temporal landscape of 556 critical mutations is constructed based on their divergence among viral haplotype clusters or repeatedly increase in frequency within at least 2 clusters,of which multiple mutations potentially conferring alterations in viral transmissibility,pathogenicity,and virulence of SARS-CoV-2 are highlighted,warranting attention.

Pinpointing the animal origins of SARS-CoV-2:a genomic approach

Understanding the origins of zoonoses is critical to developing the means to prevent zoonotic spillover into the future.Like 60% of emerging diseases in humans(Jones et al.,2008),SARS-CoV-2 is likely to have zoonotic origins with possible immediate hosts(Holmes et al.,2021;Wang et al.,2021).Determination of the origin of SARS-CoV-2,that is,when,where,and how it emerges in humans through possible zoonotic transfer,facilitates prevention of the emergence and establishment of new zoonotic diseases.