Phosphine Oxide-Nd3+ Coordination Chains with Cumulated Output Enable Efficient LED-Pumping Optical Amplification.

Near-infrared luminescent rare-earth organic complexes have attracted intensive attention in the field of optical waveguide amplification. However, their optical gains were commonly less than 4 dB/cm due to limited doping concentrations. Herein, two one-dimensional (1D) Nd3+ coordination chains, namely, [Nd(TTA)3(DBTDPO)]n (Nd1) and [Nd(TTA)3(DPEPO)]n (Nd2), bridged by phosphine oxide ligands were developed for the neodymium-doped waveguide amplifier. Despite its P-P distance being similar to DBTDPO, the different P═O orientation of DPEPO renders markedly shorter intra- and interchain Nd-Nd distances for Nd2 in comparison to Nd1. Furthermore, the weaker intermolecular interactions alleviate the quenching effect for Nd2. Therefore, Nd2 can provide more locally concentrated and radiative Nd3+ ions, leading to a larger Nd3+-characteristic 1.06 µm emission intensity and duration than Nd1. Based on embedded and evanescent-field waveguide structures, Nd2 achieves state-of-the-art gain maxima of 5.7 and 4.9 dB/cm as well as outstanding gain stability. These results indicate that controllable coordination assembly of lanthanide ions in multidimension provides a flexible approach to combine local high-density outputs and effective suppression of quenching.

Mechanisms of adverse mammary effect induced by olanzapine and therapeutic interventions in rat model.

BACKGROUND: Olanzapine antagonizes dopamine receptors and is prescribed to treat multiple psychiatric conditions. The main side effect of concern for olanzapine is weight gain and metabolic syndrome. Olanzapine induces hyperprolactinemia, however its effect on the mammary gland is poorly documented. METHODS: Rats received olanzapine by gavage or in drinking water at 1, 3, and 6 mg/kg/day for 5-40 days or 100 days, with and without coadministration of bromocriptine or aripiprazole and using once daily or continuous administration strategies. Histomorphology of the mammary gland, concentrations of prolactin, estradiol, progesterone, and olanzapine in serum, mammary gland and adipose tissue, and mRNA and protein expressions of prolactin receptors were analyzed. RESULTS: In adult and prepubescent female rats and male rats, olanzapine induced significant development of mammary glands in dose- and time-dependent manners, with histopathological hyperplasia of mammary ducts and alveoli with lumen dilation and secretion, marked increase of mammary prolactin receptor expression, a marker of breast tissue, and with mild increase of circulating prolactin. This side effect can be reversed after medication withdrawal, but long-term olanzapine treatment for 100 days implicated tumorigenic potentials indicated by usual ductal epithelial hyperplasia. Olanzapine induced mammary development was prevented with the coaddition of the dopamine agonist bromocriptine or partial agonist aripiprazole, or by continuous administration of medication instead of a once daily regimen. CONCLUSIONS: These results shed light on the previously overlooked effect of olanzapine on mammary development and present experimental evidence to support current clinical management strategies of antipsychotic induced side effects in the breast.

High-Efficiency Ultraviolet Electroluminescence from Multi-Resonance Phosphine Oxide Polycyclic Aromatics.

Efficient ultraviolet (UV) electroluminescent materials remain a great challenge, since short peak wavelength <400 nm and narrow full width at half maximum (FWHM) <50 nm are simultaneously required. In this sense, multi-resonance (MR) thermally activated delayed fluorescence (TADF) emitters featuring narrow-band emissions hold the promise for UV applications. Herein, a novel MR-TADF skeleton featuring carbazole-phosphine oxide (P=O) fused aromatics is developed to construct the first two UV MR emitters named CzP2PO and tBCzP2PO. In addition to synergistic resonance effects of P=O and N atom, sp3 -hybrid P atom renders the curved polycyclic planes of CzP2PO and tBCzP2PO, giving rise to their narrowband UV emissions with peak wavelengths <390 nm and FWHM<35 nm. Besides configuration quasi-planarization for radiation enhancement and quenching suppression, P=O moiety further enhances singlet-triplet coupling to facilitate reverse intersystem crossing, resulting in the state-of-the-art photoluminescence quantum yield of 62 % in tBCzP2PO doped films. As consequence, tBCzP2PO endowed its UV organic light-emitting diodes with the peak at 382 nm and FWHM of 32 nm, and especially the record-high external quantum efficiency (EQE) of 15.1 % among all kinds of UV devices. Our results demonstrate great potential of P=O based MR emitters in practical applications including optoelectronics, biology and medicine science.

Suramin, an antiparasitic drug, stimulates adipocyte differentiation and promotes adipogenesis.

BACKGROUND: Previous studies demonstrated that mast cells with their degranulated component heparin are the major endogenous factors that stimulate preadipocyte differentiation and promote fascial adipogenesis, and this effect is related to the structure of heparin. Regarding the structural and physiological properties of the negatively charged polymers, hexasulfonated suramin, a centuries-old medicine that is still used for treating African trypanosomiasis and onchocerciasis, is assumed to be a heparin-related analog or heparinoid. This investigation aims to elucidate the influence of suramin on the adipogenesis. METHODS: To assess the influence exerted by suramin on adipogenic differentiation of primary white adipocytes in rats, this exploration was conducted both in vitro and in vivo. Moreover, it was attempted to explore the role played by the sulfonic acid groups present in suramin in mediating this adipogenic process. RESULTS: Suramin demonstrated a dose- and time-dependent propensity to stimulate the adipogenic differentiation of rat preadipocytes isolated from the superficial fascia tissue and from adult adipose tissue. This stimulation was concomitant with a notable upregulation in expression levels of pivotal adipogenic factors as the adipocyte differentiation process unfolded. Intraperitoneal injection of suramin into rats slightly increased adipogenesis in the superficial fascia and in the epididymal and inguinal fat depots. PPADS, NF023, and NF449 are suramin analogs respectively containing 2, 6, and 8 sulfonic acid groups, among which the last two moderately promoted lipid droplet formation and adipocyte differentiation. The number and position of sulfonate groups may be related to the adipogenic effect of suramin. CONCLUSIONS: Suramin emerges as a noteworthy pharmaceutical agent with the unique capability to significantly induce adipocyte differentiation, thereby fostering adipogenesis.

Phosphine-Manipulated p-π and π-π Synergy Enables Efficient Ultralong Organic Room-Temperature Phosphorescence.

Organic room temperature phosphorescence (RTP) attracts extensive attentions, but still faces the challenge of achieving both high RTP efficiencies (ηRTP ) and long lifetimes (τRTP ), due to the intrinsic contradiction between triplet radiation and stabilization. In this work, we developed three carbazole-triphenylphosphine hybrids named xCzTPP, in which phosphine groups provide nonbonding electrons and steric hindrance to modulate intermolecular p-π and π-π interactions. With the rational orientations and spatial positions of functional groups, para-substituted pCzTPP achieves high ηRTP over 10 % and more than twofold increased τRTP (>600 ms), compared to ortho- and meta- isomers. Theoretical simulation and photophysical investigation indicate that the strongest intermolecular p-π and π-π electronic interplays of pCzTPP harmonize high transition probability of 3 pπ state and triplet stability of 3 ππ state, reflecting the p-π and π-π synergy in RTP process.

Cluster Light-Emitting Diodes Containing Copper Iodine Cube with 100 % Exciton Utilization Using Host-Cluster Synergy.

Clusters combine the advantages of organic molecules and inorganic nanomaterials, which are promising alternatives for optoelectronic applications. Nonetheless, recently emerged cluster light-emitting diodes require further excited state optimization of cluster emitters, especially to reduce population of the cluster-centered triplet quenching state (3 CC). Here we report that redox-active ligands enhance reverse intersystem crossing (RISC) of Cu4 I4 cluster for triplet-to-singlet conversion, and thermally activated delayed fluorescence (TADF) host can provide an external RISC channel. It indicates that the complementarity between TADF host and cluster in RISC transitions gives rise to 100 % triplet conversion efficiency and complete singlet exciton convergence, rendering 100-fold increased singlet radiation rate constant and tenfold decreased triplet non-radiation rate constant. We achieve a photoluminescence quantum yield of 99 % and a record external quantum efficiency of 29.4 %.

Bulk Passivation Enables Hundredfold-Enhanced Electroluminescence of Monophosphine Cu4 I4 Cubes.

Electroluminescent (EL) clusters emerged rapidly, owing to their organic-inorganic hybrid character useful for comprehensive performance integration and the potential for large-scale display and lighting applications. However, despite their good photoluminescent (PL) properties, until present, no efficient EL monodentate ligand-based clusters were reported due to structural variation during processing and excitation and exciton confinement on cluster-centered quenching states. Here we demonstrate an effective bulky passivation strategy for efficient cluster light-emitting diodes with a monophosphine Cu4 I4 cube named [TMeOPP]4 Cu4 I4 . With terminal pyridine groups, an active matrix named TmPyPB supports an effective host-cluster interplay for configuration fixation, structural stabilization, and exciton-confinement optimization. Compared to common inactive hosts, the passivation effects of TmPyPB markedly reduce trap-state densities by 24-40 % to suppress nonradiative decay, resulting in state-of-the-art PL and EL quantum yields reaching 99 % and 15.6 %, respectively, which are significantly improved by about 7-fold. TmPyPB simultaneously increases EL luminance to 104 nits, which is ≈100-fold that of the non-doped analogue.

Overcoming Efficiency Limitation of Cluster Light-Emitting Diodes with Asymmetrically Functionalized Biphosphine Cu4I4 Cubes.

Electroluminescent (EL) nanoclusters holding promise for new-generation cluster light-emitting devices (CLEDs) rapidly emerge. However, slow radiation and serious quenching of cluster emitters largely limit the device performance. Herein, we report two monofunctionalized biphosphine chelated Cu4I4 clusters [DMACDBFDP]2Cu4I4 and [DPACDBFDP]2Cu4I4. The asymmetric modification and electron-donating effect of acridine groups lead to the iodine-to-ligand charge transfer predominant excited states of the clusters, which feature thermally activated delayed fluorescence with markedly improved singlet radiative rate constants and reduced triplet nonradiative rate constants. As consequence, compared to the nonfunctionalized parent cluster, [DPACDBFDP]2Cu4I4 achieves 16-fold increased photoluminescence (81%) and 20-fold increased EL (19.5%) quantum efficiencies. Such new-record efficiencies make CLEDs achieve the state-of-the-art performance of all kinds of EL technologies.

Deep-Blue Electroluminescence from Phosphine-Stabilized Au3 Triangles and Au3 Ag Pyramids.

The optoelectronic applications of clusters emerged rapidly. Cluster light-emitting diodes (CLED) as representative hold promise as a new generation of displays and lightings. However, as one of the main challenges in electroluminescence (EL) field, until present, no deep-blue CLEDs were reported, due to the strict requirements on excited-state characteristics of clusters. Herein, two phosphine-stabilized Au3 triangle and Au3 Ag pyramid named [O(Audppy)3 ]BF4 and [O(Audppy)3 Ag](BF4 )2 were chosen to demonstrate efficient deep-blue CLEDs. The ligand-incorporated charge transfer transitions of the clusters contribute to both singlet and triplet excited states of the clusters, giving rise to phosphorescence at 460 nm and EL emissions at 436 nm. Based on device engineering, the maximum luminescence beyond 8000 nits and the chromatic coordinates with y <0.1 in deep-blue region verify the competence of CLEDs for high-resolution displays.

Organophosphine-Sandwiched Copper Iodide Cluster Enables Charge Trapping.

Herein, we report a feasible molecular design of the binuclear clusters featuring the n-p-n heterojunction of biligand-sandwiched inorganic units, which can be used as the effective charge trapper in ambipolar transistor memories with the large memory windows and the energy-saving operation. We found that the hole confinement on the p-type inorganic units is enhanced by spatial electronic anisotropy provided by the peripheral n-type organic phosphine ligands. The steric hindrance of the coordination sites, the insulating effect of the carbon-phosphorous single bonds and the parallel dual-ligand coordination mode jointly elongate the interunit distances to nanometer scale and restrain the intramolecular electronic communications, leading to the tunable and reliable charge trapping. Our results show that the spatial effect is crucial to further amplifying the electronic differences between organic and inorganic units for function enhancement.

Optimizing Charge Transfer and Out-Coupling of A Quasi-Planar Deep-Red TADF Emitter: towards Rec.2020 Gamut and External Quantum Efficiency beyond 30 .

Herein, we report a deep-red TADF emitter pCNQ-TPA, composed of quinoxaline-5,8-dicarbonitrile (pCNQ) acceptor and triphenylamine (TPA) donor. pCNQ-TPA supported its OLED with desired CIE coordinates of (0.69, 0.31) and the record maximum external quantum efficiency of 30.3 %, which is the best red TADF diode with Rec.2020 gamut for UHDTV. It is showed that through tuning pCNQ-TPA doping concentration, intra- and inter-molecular charge transfer are balanced to synchronously improve emission color saturation and TADF radiation, and remedy aggregation-induced quenching, rendering photoluminescence quantum yield (PLQY) reaching 90 % for deep-red emission peaked at ≈690 nm. Quasi-planar structure further endows pCNQ-TPA with an improved horizontal ratio of emitting dipole orientation, which increases light out-coupling ratio to 0.34 for achieving the state-of-the-art device efficiencies.

miR-378 and its host gene Ppargc1ß exhibit independent expression in mouse skeletal muscle.

MicroRNAs (miRNAs) are implicated in multiple biological processes in physiological and pathological settings. Nearly half of the known miRNAs are classified as 'intronic' miRNAs because they are embedded within the introns of protein-coding or noncoding genes. Such miRNAs were thought to be processed from primary host gene transcripts and share the promoter of their host. Recent analyses predicted that some intronic miRNAs might be transcribed and regulated as independent units, but there is little direct evidence for this in a specific biological context. Here, we focused on miR-378, which is located within the first intron of the peroxisome proliferator-activated receptor γ coactivator 1-beta (Ppargc1ß) gene and critically regulates skeletal muscle cell differentiation and muscle regeneration. We demonstrate that miR-378 and Ppargc1ß exhibit distinct expression patterns during skeletal muscle cell differentiation. In terminally differentiated adult skeletal muscle tissues of mice, miR-378 is predominantly expressed in glycolytic muscle, whereas Ppargc1ß is mainly expressed in oxidative soleus muscle. Mechanistically, miR-378, but not Ppargc1ß, is regulated by the transcription factor, MyoD, in muscle cells. Our findings identify a regulatory model of miR-378 expression, thereby helping us to understand its physiological function in skeletal muscle.

Highly Efficient Deep-Red Non-Doped Diodes Based on a T-Shape Thermally Activated Delayed Fluorescence Emitter.

Device simplification is of practical significance for organic light emitting diodes (OLEDs), and remains the great challenge for deep-red emitters. Herein, a deep-red thermally activated delayed fluorescence molecule (pTPA-DPPZ) is reported which features a T shaped structure containing two triphenylamine (TPA) donors, one either side of a planar dipyridophenazine (DPPZ) acceptor. The rational spatial arrangement of the functional groups leads to limited but sufficient molecular packing for effective carrier transport. The neat pTPA-DPPZ film achieves an around 90-fold improved radiation rate constant of 107  s-1 and the nearly unitary reverse intersystem crossing (RISC) efficiency, as well as accelerated emission decays for quenching suppression. The high radiation and RISC result in a photoluminescence quantum yield of 87 %. The bilayer OLED based on the pTPA-DPPZ emissive layer achieved the record external quantum efficiencies of 12.3 % for maximum and 10.4 % at 1000 nits, accompanied by the deep-red electroluminescence with the excellent color purity.

Simply Structured Near-Infrared Emitters with a Multicyano Linear Acceptor for Solution-Processed Organic Light-Emitting Diodes.

Near-infrared (NIR) organic light-emitting diodes (OLEDs) show great potential in a variety of applications including sensors, night vision, and information security. Despite the superiority of thermally activated delayed fluorescence (TADF) in 100 % exciton harvesting, the development of NIR TADF OLEDs is still a great challenge, especially in terms of solution-processing technology. In this work, a multicyano acceptor of 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofurance (TCF) with strong electron-withdrawing ability was employed to construct solution-processible NIR emitters, CzTCF and tBCzTCF, with the feature of donor-π-acceptor (D-π-A) structure. The significantly enhanced intermolecular charge transfer effects not only render the deep-red and NIR emissions of CzTCF and tBCzTCF films, respectively, but also lead to their typical TADF characteristics. Consequently, the nondoped solution-processed NIR OLED based on tBCzTCF was successfully demonstrated with the peak wavelength of 715 nm, which paves the way for developing NIR emitters without polycyclic aromatic cores and heavy-metal ions.

Highly Efficient Solution-Processable Nanophosphor with Ambipolar Shell.

Super-resolution display (SRD) is crucial to all super-resolution processing technologies for visualization terminals. Herein, as a proof-of-concept, an iridium-complexed nanoemitter, [Ir(CzPOPBI)3 ] (CzPOPBI=9,9'-(3,3'-(4-(1-(3-(4-(diphenylphosphoryl)phenoxy)propyl)-1H-benzo[d]imidazol-2-yl)-1,2-phenylene)bis(oxy)bis(propane-3,1-diyl))bis(3,6-di-tert-butyl-9H-carbazole)), with a core-shell structure for charge and exciton spatial allocation is reported, the ambipolar shell of which can balance shell-to-core charge transfer and excess charge export. As a result, top performance of spin-coated host-free bilayer devices was realized, owing to the simultaneous exciton confinement in the core and exciton-charge quenching suppression. The competence of [Ir(CzPOPBI)3 ] as a single-molecule emissive layer of nanopixel units shows the great potential of this kind of organic core-shell system for high-performance SRD applications.

Ultrasensitive near-infrared fluorescence-enhanced probe for in vivo nitroreductase imaging.

Nitroreductase (NTR) can be overexpressed in hypoxic tumors, thus the selective and efficient detection of NTR is of great importance. To date, although a few optical methods have been reported for the detection of NTR in solution, an effective optical probe for NTR monitoring in vivo is still lacking. Therefore, it is necessary to develop a near-infrared (NIR) fluorescent detection probe for NTR. In this study, five NIR cyanine dyes with fluorescence reporting structure decorated with different nitro aromatic groups, Cy7-1-5, have been designed and explored for possible rapid detection of NTR. Our experimental results presented that only a para-nitro benzoate group modified cyanine probe (Cy7-1) could serve as a rapid NIR fluorescence-enhanced probe for monitoring and bioimaging of NTR. The structure-function relationship has been revealed by theoretical study. The linker connecting the detecting and fluorescence reporting groups and the nitro group position is a key factor for the formation of hydrogen bonds and spatial structure match, inducing the NTR catalytic ability enhancement. The in vitro response and mechanism of the enzyme-catalyzed reduction of Cy7-1 have been investigated through kinetic optical studies and other methods. The results have indicated that an electro-withdrawing group induced electron-transfer process becomes blocked when Cy7-1 is catalytically reduced to Cy7-NH2 by NTR, which is manifested in enhanced fluorescence intensity during the detection process. Confocal fluorescence imaging of hypoxic A549 cells has confirmed the NTR detection ability of Cy7-1 at the cellular level. Importantly, Cy7-1 can detect tumor hypoxia in a murine hypoxic tumor model, showing a rapid and significant enhancement of its NIR fluorescence characteristics suitable for fluorescence bioimaging. This method may potentially be used for tumor hypoxia diagnosis.

Rationally investigating the influence of T1 location on electroluminescence performance of aryl amine modified phosphine oxide materials.

The correspondence between triplet location effect and host-localized triplet-triplet annihilation and triplet-polaron quenching effects was performed on the basis of a series of naphthyldiphenylamine (DPNA)-modified phosphine oxide hosts. The number and ratio of DPNA and diphenylphosphine oxide was adjusted to afford symmetrical and unsymmetrical molecular structures and different electronic environments. As designed, the first triplet (T1 ) states were successfully localized on the specific DPNA chromophores. Owing to the meso- and multi-insulating linkages, identical optical properties and comparable electrical performance was observed, including the same first singlet (S1 ) and T1 energy levels to support the similar singlet and triplet energy transfer and the close frontier molecular orbital energy levels. This established the basis of rational investigation on T1 location effect without interference from other optoelectronic factors.

Solution-processible brilliantly luminescent Eu(III) complexes with host-featured phosphine oxide ligands for monochromic red-light-emitting diodes.

A series of solution-processible electroluminescent (EL) Eu(3+) complexes were constructed with a self-host strategy, in which neutral ligands were employed as functionalized bidentate phosphine oxide (PO) ligands named DPEPOArn (DPEPO = bis(2-(diphenylphosphino)phenyl) ether oxide). The solubility of these complexes was dramatically improved owing to the increased ratios of organic components. This further enhanced the antenna effect of these ligands in both singlet and triplet energy-transfer processes to support high photoluminescent quantum yields (PLQYs) up to 86 % for their Eu(3+) complexes, which is outstanding among conjugated Eu(3+) complexes. Density function theory (DFT) simulations and electrochemical analysis further verified the contributions of DPEPOArn to the carrier injecting/transporting ability of the complexes. In this sense, these functionalized PO ligands served as hosts in optoelectronic processes, which rendered the self-host feature of their Eu(3+) complexes. With the enhanced electrical properties, the spin-coated single-layer organic light-emitting diodes (OLEDs) of these complexes achieved improved low driving voltages, such as onset voltages about 6 V, compared to their Eu(3+)-contained red-emitting polymeric analogues. [Eu(DBM)3DPEPODPNA2] (DBM = 1,3-diphenylpropane-1,3-dione, DPNA = diphenylnaphthylamine) with the most enhanced electrical properties and suitable frontier molecular orbital (FMO) and triplet state locations endowed its devices with the biggest maximum luminance of >90 cd m(-2) and the highest EL efficiencies. This work verified the potential of small molecular EL Eu(3+) complexes for solution-processed OLEDs through rational function integrations.

Delayed room temperature phosphorescence enabled by phosphines.

Organic ultralong room-temperature phosphorescence (RTP) usually emerges instantly and immediately decays after excitation removal. Here we report a new delayed RTP that is postponed by dozens of milliseconds after excitation removal and decays in two steps including an initial increase in intensity followed by subsequent decrease in intensity. The delayed RTP is achieved through introduction of phosphines into carbazole emitters. In contrast to the rapid energy transfer from single-molecular triplet states (T1) to stabilized triplet states (Tn*) of instant RTP systems, phosphine groups insert their intermediate states (TM) between carbazole-originated T1 and Tn* of carbazole-phosphine hybrids. In addition to markedly increasing emission lifetimes by ten folds, since TM → Tn* transition require >30 milliseconds, RTP is thereby postponed by dozens of milliseconds. The emission character of carbazole-phosphine hybrids can be used to reveal information through combining instant and delayed RTP, realizing multi-level time resolution for advanced information, biological and optoelectronic applications.