Singlet fission (SF), a multiple exciton generation process that generates two triplet excitons after the absorption of one photon, can potentially enable more efficient solar cell designs by ...harvesting energy normally lost as heat. While low-bandgap conjugated polymers are highly promising candidates for efficient SF-based solar cells, few polymer materials capable of SF have been reported because the SF process in polymer chains is poorly understood. Using transient spectroscopy, we demonstrate a new, highly efficient (triplet yield of 160-200%) isoindigo-based donor-acceptor polymer and show that the triplet pairs are directly emissive and exhibit a time-dependent energy evolution. Importantly, aggregation in poor solvents and in films significantly lowers the singlet energy, suppressing triplet formation because the energy conservation criterion is no longer met. These results suggest a new design rule for developing intramolecular SF capable low-bandgap conjugated polymers, whereby inter-chain interactions must be carefully engineered.
3,4-Ethylene dioxythiophene (EDOT), as a monomer of commercial conductive poly(3,4-ethylene dioxythiophene) (PEDOT), has been facilely incorporated into a series of new π-conjugated polymer-based ...photocatalysts,
, BSO
-EDOT, DBT-EDOT, Py-EDOT and DFB-EDOT, through atom-economic C-H direct arylation polymerization (DArP). The photocatalytic hydrogen production (PHP) test shows that donor-acceptor (D-A)-type BSO
-EDOT renders the highest hydrogen evolution rate (HER) among the linear conjugated polymers (CPs) ever reported. A HER up to 0.95 mmol h
/6 mg under visible light irradiation and an unprecedented apparent quantum yield of 13.6% at 550 nm are successfully achieved. Note that the photocatalytic activities of the C-H/C-Br coupling-derived EDOT-based CPs are superior to those of their counterparts derived from the classical C-Sn/C-Br Stille coupling, demonstrating that EDOT is a promising electron-rich building block which can be facilely integrated into CP-based photocatalysts. Systematic studies reveal that the enhanced water wettability by the integration of polar BSO
with hydrophilic EDOT, the increased electron-donating ability by O-C p-π conjugation, the improved electron transfer by D-A architecture, broad light harvesting, and the nano-sized colloidal character in a H
O/NMP mixed solvent rendered BSO
-EDOT as one of the best CP photocatalysts toward PHP.
On the road to recovery: The dynamic apertures and superhydrophobic surfaces of the metal–organic framework ZIF‐8 result in its extraordinary ability to selectively adsorb alcohols. When incorporated ...into a polymer matrix, the ZIF‐8 nanoparticles provide preferential pathways for the permeation of organic compounds and allow the efficient pervaporative recovery of bio‐alcohols from fermentation broths (see picture).
Constituting approximately 10% of flowering plant species, orchids (Orchidaceae) display unique flower morphologies, possess an extraordinary diversity in lifestyle, and have successfully colonized ...almost every habitat on Earth. Here we report the draft genome sequence of Apostasia shenzhenica, a representative of one of two genera that form a sister lineage to the rest of the Orchidaceae, providing a reference for inferring the genome content and structure of the most recent common ancestor of all extant orchids and improving our understanding of their origins and evolution. In addition, we present transcriptome data for representatives of Vanilloideae, Cypripedioideae and Orchidoideae, and novel third-generation genome data for two species of Epidendroideae, covering all five orchid subfamilies. A. shenzhenica shows clear evidence of a whole-genome duplication, which is shared by all orchids and occurred shortly before their divergence. Comparisons between A. shenzhenica and other orchids and angiosperms also permitted the reconstruction of an ancestral orchid gene toolkit. We identify new gene families, gene family expansions and contractions, and changes within MADS-box gene classes, which control a diverse suite of developmental processes, during orchid evolution. This study sheds new light on the genetic mechanisms underpinning key orchid innovations, including the development of the labellum and gynostemium, pollinia, and seeds without endosperm, as well as the evolution of epiphytism; reveals relationships between the Orchidaceae subfamilies; and helps clarify the evolutionary history of orchids within the angiosperms.
•The prevalence of anxiety and depression symptom was 7.7% and 12.2%, respectively.•Having confirmed and suspected cases in family members or relatives was associated with the higher risk of ...depression symptom.•Self-reported health condition was strongly associated with risk of anxiety and depression symptom.
: Although studies have suggested experiencing the epidemic of severe infectious diseases increased the prevalence of mental health problems, the association between COVID-19 epidemic and risk of anxiety and depression symptom in college students in China was unclear.
: A large cross-sectional online survey with 44,447 college students was conducted in Guangzhou, China. The Zung's Self-rating Anxiety Scale (SAS) and the Center for Epidemiologic Studies Depression Scale (CES-D Scale) were used to define the anxiety and depression symptom, respectively. Multivariable logistic regression models were used to analyze the association between COVID-19 epidemic and risk of anxiety and depression symptom.
: The prevalence of anxiety and depression symptom was 7.7% (95% confidence interval CI: 7.5%, 8.0%) and 12.2% (95%CI: 11.9%, 12.5%), respectively. Compared with students who reported have not infected or suspected cases in family members and relatives, students who reported having confirmed (OR=4.06; 95%CI: 1.62, 10.19; P = 0.003), and suspected (OR=2.11; 95%CI: 1.11, 4.00; P = 0.023) cases in family members and relatives had higher risk of depression symptom. Additionally, the proportions of students with anxiety and depression symptom reported more demand of psychological knowledge and interventions than those without (P<0.001).
: All the data in this study was collected through online questionnaire, and we did not evaluate the reliability and validity.
: The prevalence of anxiety and depression symptom was relatively low in college students, but the COVID-19 epidemic-related factors might be associated with higher depression symptom risk.
In this contribution, we developed a simple, scalable, and universal strategy to exfoliate conjugated porous polymers (CPPs) into 2D nanosheets. A series of pyrenyl (
Py
)-, benzene (
B
)-, thienyl (
...T
)-, thieno3,2-
b
thiophene (
Tt
)- and dithieno3,2-
b
:2′,3′-
d
thiophene (
Ttt
)-based CPPs were facilely exfoliated into 2D ultrathin sheets with a thickness of 5-18 nm in reasonable yields of 6-20% upon sonication in
N
-methyl pyrrolidone. Owing to more exposed active sites and shorter migration distances of charge carriers, the photocatalytic hydrogen production rate of the CPP 2-D nanosheets is 1.5-20 times higher than those of their bulk counterparts. The current study represents the first systematic report on the solvent-assisted exfoliation of CPP materials to produce 2D ultrathin lamellae from bulk CPPs with common structures, which might provide new possibilities for the practical application of 2D CPPs.
A common strategy is developed to exfoliate bulk CPPs into nanosheets for highly efficient PHP performance.
Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Prognosis is often unfavorable. In this study, the effects of microRNA‐802 (miR‐802) on HCC progression were assessed ...in vivo and in vitro. miR‐802 was found to be significantly upregulated in HCC tumor tissue compared to paired adjacent nontumor tissue. In vitro, transfection with a miR‐802 mimic accelerated SMMC‐7721 cellular proliferation, increased accumulation of the cell‐cycle S‐phase cell populations, as well as cell migration. In vivo injection of a miR‐802 agomir promoted HCC proliferation in nude mice. Targets of miR‐802 were predicted by miRWalk, miRanda, RNA22, and Targetscan. By luciferase reporter assay RUNX3 was identified as a direct target of miR‐802. As judged by western blot analysis, RUNX3 was upregulated when miR‐802 was inhibited. These data demonstrate increased miR‐802 expression in patients with HCC and that miR‐802 overexpression promotes tumor cell growth, in a RUNX3‐dependent manner.
Our data demonstrate increased microRNA‐802 (miR‐802) expression in patients with hepatocellular carcinoma and that miR‐802 overexpression promotes tumor cell growth, in a RUNX3‐dependent manner.
Molecular packing in organic single crystals greatly influences their charge transport properties but can hardly be predicted and designed because of the complex intermolecular interactions. In this ...work, we have realized systematic fine-tuning of the single-crystal molecular packing of five benzodifurandione-based oligo(p-phenylenevinylene) (BDOPV)-based small molecules through incorporation of electronegative fluorine atoms on the BDOPV backbone. While these molecules all exhibit similar column stacking configurations in their single crystals, the intermolecular displacements and distances can be substantially modified by tuning of the amounts and/or the positions of the substituent fluorine atoms. Density functional theory calculations showed that the subtle differences in charge distribution or electrostatic potential induced by different fluorine substitutions play an important role in regulating the molecular packing of the BDOPV compounds. Consequently, the electronic couplings for electron transfer can vary from 71 meV in a slipped stack to 201 meV in a nearly cofacial antiparallel stack, leading to an increase in the electron mobility of the BDOPV derivatives from 2.6 to 12.6 cm2 V–1 s–1. The electron mobility of the five molecules did not show a good correlation with the LUMO levels, indicating that the distinct difference in charge transport properties is a result of the molecular packing. Our work not only provides a series of high-electron-mobility organic semiconductors but also demonstrates that fluorination is an effective approach for fine-tuning of single-crystal packing modes beyond simply lowering the molecular energy levels.
Aging is a worldwide challenge, and it is accompanied by the accumulation of senescent cells. Cellular senescence is traditionally defined as permanent cell growth arrest and currently includes the ...senescence-associated secretory phenotype (SASP). There are two main types of cellular senescence, including telomere-dependent replicative senescence and stress-induced premature senescence. The process of cellular senescence is mainly controlled by two effector pathways, namely, the p53-p21 and p16-retinoblastoma protein (pRB) pathways. Vascular smooth muscle cells (VSMCs) are integral parts of arteries and play an important role in vascular structure and function. VSMC senescence may be triggered by many factors, such as angiotensin II, oxidative stress, inflammation, DNA damage, and small molecule compounds. These inducers are able to genetically and epigenetically regulate VSMC senescence. The senescence of VSMCs together with the SASP contributes to chronic vascular inflammation, the loss of arterial function, and the development of age-related diseases. Current evidence suggests that the senescence of VSMCs might be harmful to individual health, whereas its influence on the lifespan is not clear. The purpose of this paper was to review the current knowledge regarding VSMC senescence and its relevance to hypertension, atherosclerosis, and diabetes, as well as the potential mechanisms responsible for VSMC senescence in these age-related diseases.
•Senescence includes growth arrest and senescence-associated secretory phenotype.•Senescence could be divided into replicative senescence and premature senescence.•Oxidative stress and inflammation are important in senescence & age-related diseases.•Vascular smooth muscle cell senescence might be harmful to age-related diseases.
Osteoarthritis (OA) is a degenerative joint disease characterized by destruction of articular cartilage. The inflammatory response is the most important factor affecting the disease process. As ...interleukin‐1β (IL‐1β) stimulates several key mediators in the inflammatory response, it plays a major role in the pathogenesis of OA. Maslinic acid (MA) is a natural compound distributed in olive fruit. Previous studies have found that maslinic acid has an inhibitory effect on inflammation, but its specific role in the progression of OA disease has not been studied so far. In this study, we aim to assess the protective effect of MA on OA progression by in vitro and in vivo experiments. Our results indicate that, in IL‐1β‐induced inflammatory response, MA is effective in attenuating some major inflammatory mediators such as nitric oxide (NO) and prostaglandin E2, and inhibits the expression of IL‐6, inducible nitric oxide synthase, cyclooxygenase‐2, and tumor necrosis factor‐α (TNF‐α) in a concentration‐dependent manner. Also, MA downregulated the expression levels of thrombospondin motif 5 (ADAMTS5) and matrix metalloproteinase 13 in chondrocytes, resulting in reduced degradation of its extracellular matrix. Mechanistically, MA exhibits an anti‐inflammatory effect by inactivating the PI3K/AKT/NF‐κB pathway. In vivo, the protective effect of MA on OA development can be detected in a surgically induced mouse OA model. In summary, these findings suggest that MA can be used as a safe and effective potential OA therapeutic strategy.
Maslinic acid (MA) could prevent IL‐1β‐associated inflammation as well as extracellular matrix (ECM) degradation in human osteoarthritis (OA) chondrocytes. The potential mechanism involved in the protective effect of MA was that it could reverse inflammation‐related destruction via inhibiting PI3K/AKT/NF‐κB pathways activation. MA ameliorates OA progression in vivo via inhibiting the devastation of cartilage surface, cartilage calcification, and osteophytes formation.
PDF
