Aggregative Luminescence from CsPbBr3 Perovskite Precursors.

Understanding the properties of the precursor can provide deeper insight into the crystallization and nucleation mechanisms of perovskites, which is vital for the solution-process device performance. Herein, we conducted a detailed investigation into the photophysics properties of CsPbBr3 precursors in a broad concentration and various solvents. The precursor transformed from the solution state into the colloidal state and exhibited aggregation-induced emission character as the concentration increased. The aggregative luminescence from the precursors originates from the polybromide plumbous that is formed through the coordination of solvent molecules to the lead metal center. Two adducts with monodentate (PbBr2 ⋅ solvent) and bidentate (PbBr2 ⋅ 2solvent) ligands can be obtained, accompanied by emission with photoluminescence at 610 and 565 nm, respectively. Furthermore, the aggregative luminescence intensity and color could be regulated by changing the solvent and precursor ratio. Besides, we discussed the difference between the molecular aggregate in the organic system and the ionic aggregate in the inorganic system: the ionic aggregate is composed of solvated ions rather than individual molecules as in organic systems, which could possess properties that ions do not have. The fluorescence that is sensitive to Pb2+ coordination reported here could be applied to screen perovskite additives and judge the precursor aging.

Aqueous Circularly Polarized Luminescence Induced by Homopolypeptide Self-Assembly.

Remarkable advances have been achieved in solution self-assembly of polypeptides from the perspective of nanostructures, mechanisms, and applications. Despite the intrinsic chirality of polypeptides, the promising generation of aqueous circularly polarized luminescence (CPL) based on their self-assembly has been rarely reported due to the weak fluorescence of most polypeptides and the indeterminate self-assembly mechanism. Here, we propose a facile strategy for achieving aqueous CPL based on the self-assembly of simple homopolypeptides modified with a terminal group featuring both twisted intramolecular charge transfer and aggregation-induced emission properties. A morphology-dependent CPL can be observed under different self-assembly conditions by altering the solvents. A nanotoroid-dispersed aqueous solution with detectable CPL can be obtained by using tetrahydrofuran as a good solvent for the self-assembly, which is attributed to the involvement of the terminal group in the chiral environment formed by the homopolypeptide chains. However, such a chiral packing mode cannot be realized in nanorods self-assembled from dioxane, resulting in an inactive CPL phenomenon. Furthermore, CPL signals can be greatly amplified by co-assembly of homopolypeptides with the achiral small molecule derived from the terminal group. This work not only provides a pathway to construct aqueous CPL-active homopolypeptide nanomaterials but also reveals a potential mechanism in the self-assembly for chiral production, transfer, and amplification in polypeptide-based nanostructures.

Different expression of LHR, PRLR, GH and IGF1 during testicular development of yak.

Luteinizing hormone receptor (LHR), prolactin receptor (PRLR), growth hormone (GH) and insulin-like growth factor 1 (IGF1) have been shown to be key regulators of germ cell development. However, the role of LHR, PRLR, GH and IGF1 in the development of yak testis remains unclear. In this study, we aimed to describe and compare gene expression and protein localization of LHR, PRLR, GH and IGF1 in the development of yak testes. Testes were collected from 6, 24, 36 and 72 months yak, and the kidney, liver, testicular, lung, skeletal muscle, heart and spleen tissues were collected from 36 months yak. The quantitative real-time PCR (qRT-PCR) results showed that the expression of these four genes was widely expressed in kidney, liver, testicular, lung, skeletal muscle, heart and spleen, while the LHR and PRLR were highly expressed in the kidney, skeletal muscle and testis, and higher levels of GH and IGF were expressed in spleen and testis. Moreover, the mRNA expression of these genes in adults was higher than in pre-pubertal yak. In the testis, the LHR-, PRLR-, GH- and IGF1-positive signals were detected in the Leydig cells of the 6 months, while the intense positive signals were discovered in Leydig cells, spermatogonia and spermatocytes of the 36 and 72 months. Thus, LHR, PRLR, GH and IGF1 may be involved in the development of spermatids and spermatocytes, and in the regulation of spermatogonia proliferation and Leydig cell function.

Effects of pig manure containing copper and zinc on microbial community assessed via phospholipids in soils.

Pig manure (PM) is widely used as an organic fertilizer to increase yields of crops. Excessive application of compost containing relatively great concentrations of copper (Cu) and zinc (Zn) can change soil quality. To clarify the effects of different rates of application and to determine the optimal rate of fertilization, PM containing 1,115 mg Cu kg(-1), dry mass (dm) and 1,497 mg Zn kg(-1), dm was applied to alkaline soil at rates of 0, 11, 22, 44, 88, and 222 g PM kg(-1), dm. Phospholipid fatty acids (PLFAs) were used to assess soil microbial community composition. Application of PM resulted in greater concentrations of total nitrogen (TN), NH4 (+)-N, NO3 (-)-N, total carbon (TC), soil organic matter (SOM) but lesser pH values. Soils with application rates of 88-222 g PM kg(-1), dm had concentrations of total and EDTA-extractable Cu and Zn significantly greater than those in soil without PM, and concentrations of T-Cu and T-Zn in these amended soils exceeded maximum limits set by standards in china. Except in the soil with a rate of 11 g PM kg(-1), dm, total bacterial and fungal PLFAs were directly proportional to rate of application of PM. Biomasses of bacteria and fungi were significantly greater in soils with application rates of 44-222 g PM kg(-1), dm than in the soil without PM. SOM, TC and EDTA-Zn had the most direct influence on soil microbial communities. To improve fertility of soils and maintain quality of soil, rate of application should be 22-44 g PM kg(-1) dm, soil containing Cu and Zn.

Boosting Luminescence Efficiency of Near-Infrared-II Aggregation-Induced Emission Luminogens via a Mash-Up Strategy of π-Extension and Deuteration for Dual-Model Image-Guided Surgery.

The simultaneous pursuit of accelerative radiative and restricted nonradiative decay is of tremendous significance to construct high-luminescence-efficiency fluorophores in the second near-infrared wavelength window (NIR-II), which is seriously hindered by the energy gap laws. Herein, a mash-up strategy of π-extension and deuteration is proposed to efficaciously ameliorate the knotty problem. By extending the π-conjugation of the aromatic fragment and introducing an isotope effect to the aggregation-induced emission luminogen (AIEgen), an improved oscillator strength (f), coupled with suppressed deformation and high-frequency oscillation in the excited state, are successively implemented. In this case, a faster rate of radiative decay (kr) and restricted nonradiative decay (knr) are simultaneously achieved. Moreover, the preeminent emissive property of AIEgen in the molecular state could be commendably inherited by the aggregates. The corresponding NIR-II emissive AIEgen-based nanoparticles display high brightness, large Stokes shift, and superior photostability simultaneously, which can be applied for image-guided cancer and sentinel lymph node (SLN) surgery. This work thus provides a rational roadmap to improve the luminescence efficiency of NIR-II fluorophores for biomedical applications.

Mitochondria-Targeting AIEgens as Pyroptosis Inducers for Boosting Type-I Photodynamic Therapy of Tongue Squamous Cell Carcinoma.

The development of a photosensitizer (PS) that induces pyroptosis could be a star for photodynamic therapy (PDT), particularly with type-I PSs that produce reactive oxygen species (ROS) in a hypoxic tumor microenvironment. Since pyroptosis is a recently characterized cell death pathway, it holds promise for advancing PDT in oncology, with PSs playing a critical role. Herein, we develop a PS named Th-M with aggregation-induced emission (AIE) characteristics for type-I PDT against tongue squamous cell carcinoma (TSCC). Th-M stands out for its exceptional mitochondrial-targeting ability, which triggers mitochondrial dysfunction and leads to Caspase-3 and Gasdermin E (GSDME) cleavage under white light irradiation, inducing pyroptosis in TSCC cells. Our studies verify the effectiveness of Th-M in destroying cancer cells in vitro and suppressing tumor growth in vivo while also demonstrating a favorable biosafety profile. This work pioneers the application of Th-M as a mitochondria-targeted, type-I PS that leverages the mechanism of pyroptosis, offering a potent approach for the treatment of TSSC with promising implications for future PDT of cancers.

Perovskite Light-Emitting Diodes with EQE Exceeding 28% through a Synergetic Dual-Additive Strategy for Defect Passivation and Nanostructure Regulation.

Quasi-2D perovskites have long been considered to have favorable "energy funnel/cascade" structures and excellent optical properties compared with their 3D counterparts. However, most quasi-2D perovskite light-emitting diodes (PeLEDs) exhibit high external quantum efficiency (EQE) but unsatisfactory operating stability due to Auger recombination induced by high current density. Herein, a synergetic dual-additive strategy is adopted to prepare perovskite films with low defect density and high environmental stability by using 18-crown-6 and poly(ethylene glycol) methyl ether acrylate (MPEG-MAA) as the additives. The dual additives containing COC bonds can not only effectively reduce the perovskite defects but also destroy the self-aggregation of organic ligands, inducing the formation of perovskite nanocrystals with quasi-core/shell structure. After thermal annealing, the MPEG-MAA with its CC bond can be polymerized to obtain a comb-like polymer, further protecting the passivated perovskite nanocrystals against water and oxygen. Finally, state-of-the-art green PeLEDs with a normal EQE of 25.2% and a maximum EQE of 28.1% are achieved, and the operating lifetime (T50 ) of the device in air environment is over ten times increased, providing a novel and effective strategy to make high efficiency and long operating lifetime PeLEDs.

Molecular Engineering of Thermally Activated Delayed Fluorescence Emitters with Aggregation-Induced Emission via Introducing Intramolecular Hydrogen-Bonding Interactions for Efficient Solution-Processed Nondoped OLEDs.

Purely organic luminescent materials concurrently exhibiting thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) features are in great demand due to their high efficiency in aggregation-state toward efficient nondoped OLEDs. Herein, a class of TADF emitters adopting phenyl(pyridyl)methanone as electron-accepting segments and di(tert-butyl)carbazole and 9,9-dimethyl-9,10-dihydroacridine (or phenoxazine) as electron-donating groups are designed and synthesized. The existence of intramolecular hydrogen bonding is conducive to minish the energy difference between a singlet and a triplet (ΔEst), suppress nonradiative decay, and increase the luminescence efficiency. By using 3CPyM-DMAC as the emitter, the nondoped device via a solution process realize a high current efficiency (CE) and external quantum efficiency (EQE) of 35.4 cd A-1 and 11.4%, respectively, which is superior to that of CBM-DMAC with a CE and EQE of 14.3 cd A-1 and 6.7%. This work demonstrates a promising tactic to the establishment of TADF emitters with AIE features via introducing intramolecular hydrogen bonding.

A mitochondria-targeted single fluorescence probe for separately and continuously visualizing H2S and Cys with multi-response signals.

Hydrogen sulfide and cysteine are momentous endogenous regulators of many physiological processes and maintain a dynamic balance of redox in living organisms. To investigate the inter-relationship of them in vivo, there is a pressing need to develop analytical molecular tools to identify related biomolecules. We construct a mitochondria-targeted single fluorescence probe (Mit-CM) for separately and continuously visualizing H2S, Cys and H2S/Cys with multi-response fluorescence signals. Mit-CM has the following advantages: (Ⅰ) colorimetric and ratiometric: two well-separated emission bands can ensure accurate detection of the analyte and significant color changes contribute to rapid identification of the analyte by the naked eye; (Ⅱ) mitochondrial localization: study the physiological functions of H2S and Cys in mitochondria; (Ⅲ) separate and continuous detection of H2S and Cys: reveal the inter-relationship and interconversion of them in biological system. Moreover, the desirable attributes of low cytotoxicity, better biocompatibility and excellent mitochondria enrichment ability indicate that Mit-CM can be employed to achieve detection and observe distribution of H2S, Cys and H2S/Cys in living organism.

A novel isophorone-based red-emitting/NIR probe for thiophenol and its application in real water sample and vivo.

Fast, highly selective and sensitive thiophenol probes are highly desirable in the field of bioimaging and environmental monitoring. For that, based on the mechanism that thiophenol can effectively cleave the sulfonamide bond selectively, we herein report a dicyanoisophorone-based Red-emitting/NIR probe for thiophenol detection. This probe had some desirable properties such as rapid response, high selectivity and sensitivity, remarkable large Stokes shift (181 nm), Red-emitting/NIR fluorescence region and low LOD value (80 nM, according to 3σ/s). Moreover, this novel Red-emitting/NIR probe can potentially be applied to the detection of thiophenols in real water samples quantitatively and fluorescent imaging in living cells and zebrafishes.

Molecular Cloning and Characterization of SYCP3 and TSEG2 Genes in the Testicles of Sexually Mature and Immature Yak.

Testis-specific genes play an essential part in the centromere union during meiosis in male germ cells, spermatogenesis, and in fertility. Previously, there was no research report available on the expression pattern of SYCP3 and TSEG2 genes in different ages of yaks. Therefore, the current research compared the expression profiling of SYCP3 and TSEG2 genes in testes of yaks. The expression pattern of SYCP3 and TSEG2 mRNA was investigated using qPCR, semi-quantitative PCR, western blot, immunohistochemistry, and molecular bioinformatics. Our findings displayed that SYCP3 and TSEG2 genes were prominently expressed in the testicles of yaks as compared to other organs. On the other hand, the protein encoded by yak SYCP3 contains Cor1/Xlr/Xmr conserved regions, while the protein encoded by yak TSEG2 contains synaptonemal complex central element protein 3. Additionally, multiple alignments sequences indicated that proteins encoded by Datong yak SYCP3 and TSEG2 were highly conserved among mammals. Moreover, western blot analysis specified that the molecular mass of SYCP3 protein was 34-kDa and TSEG2 protein 90-kDa in the yak. Furthermore, the results of immunohistochemistry also revealed the prominent expression of these proteins in the testis of mature yaks, which indicated that SYCP3 and TSEG2 might be essential for spermatogenesis, induction of central element assembly, and homologous recombination.

Synthesis of a selective ratiometric fluorescent probe based on Naphthalimide and its application in human cytochrome P450 1A.

Cytochrome P450s have brought considerable attention to researchers for their significant correlations with metabolic behaviors of procarcinogenic chemicals. To better understand the roles of CYP1A in biological and physiological systems, we developed a novel ratiometric fluorescence probe N-((2-hydroxyl ethoxy) ethyl)- 4-methoxy-1, 8-naphthalimide (NEMN) allowing for selectively and sensitively monitoring the target enzymes under physiological conditions and living cells. The probe was designed based on substrate predilection of CYP1A and its outstanding O-dealkylation capacity, and 1, 8-naphthalimide was chosen as fluorophore on account of its desirable photophysical properties. Absorption and emission spectra of the probe solution and reacted metabolism showed obvious red-shift with remarkable colour changes, which indicated that NEMN could be a promising ratiometric detector of CYP1A. Additionally, the selectivity assays displayed that NEMN only sensitive to CYP1A1 and CYP1A2 enzymes with scarce interference of other CYPs. Furthermore, the excellent linear relationships between the ratio of fluorescent intensities and incubation time and enzymes concentration signified time- and concentration- dependence of the probe, which were of desire benefit to quantify and monitor the CYP1A-involved biological behaviors in physiological conditions. The assay in real living samples (Human liver microsomes) further proved the analytical utility of the probe. Finally, the cytotoxicity assay and confocal fluorescence imaging demonstrated that this probe was of great promise for detecting the activity of endogenous CYP1A in human living cells.