On the nature of Cu-carbon interaction through N-modification for enhanced ethanol synthesis from syngas and methanol.

Direct conversion of syngas into ethanol is an attractive process because of its short route and high-added value, but remains an enormous challenge due to the low selectivity caused by unclear active sites. Here, the Cu(111) supported N-modified graphene fragments C13-mNm/Cu(111) (m = 0-2) are demonstrated to be an efficient catalyst for fabricating ethanol from syngas and methanol. Our results suggest that the Cu-carbon interaction not only facilitates CO activation, but also significantly affects the adsorption stability of C2 intermediates and finally changes the fundamental reaction mechanism. The impeded hydrogenation performance of C13/Cu(111) due to the introduced Cu-carbon interaction is dramatically improved by N-doping. Multiple analyses reveal that the promoted electron transfer and the enhanced electron endowing ability of C13-mNm/Cu(111) (m = 1-2) to the co-adsorbed CH3CHxOH (x = 0-1) and H are deemed to be mainly responsible for the remarkable enhancement in hydrogenation ability. From the standpoint of the frontier molecular orbital, the decreased HOMO-LUMO gap and the increased overlap extent of HOMO and LUMO with the doping of N atoms also further verify the more facile hydrogenation reactions. Clearly, the Cu-carbon interaction through N-modification is of critical importance in ethanol formation. The final hydrogenation reaction during ethanol formation is deemed to be the rate-controlling step. The insights gained here could shed new light on the nature of Cu-carbon interaction in carbon material modified Cu-based catalysts for ethanol synthesis, which could be extended to design and modify other metal-carbon catalysts.

Design and Solvothermal Synthesis of Polyoxometalate-Based Cu(II)-Pyrazolate Photocatalytic Compounds for Solar-Light-Driven Hydrogen Evolution.

Polyoxometalates (POMs) are known for their photocatalytic hydrogen production activity, but their solubility and limited stability often restrict their practical applications. Herein, we designed and solvothermally synthesized two new Cu-H2bpz (3,3',5,5'-tetramethyl-4,4'-bipyrazole, abbreviated as H2bpz) compounds, namely, Cu0.5(H2bpz)(NO3) (1) and Cu(Hbpz)(Cl)·DMF (2), and three new polyoxometalate-based Cu(II)-pyrazolate compounds, namely, Cu(PW12O40)0.5(H2bpz)2(H2O)·(OH)0.5(H2O)5.5 (3), Cu(HPMo12O40)(H2bpz)2(H2O)2·(H2O)4 (4), and Cu2(SiW12O40)(H2bpz)3(H2O)3·(H2O)6 (5). Compound 3 (Cu(PW12O40)0.5(H2bpz)2(H2O)·(OH)0.5(H2O)5.5) exhibits the best photocatalytic activity of 44.4 µ L h-1 g-1, which may be related to the stability of compounds. Herein, the solvothermal method has been proven to be an effective method in synthesizing stable organic-inorganic hybrid compounds with soluble POMs, metal ions, and organic ligands. Thus, heterogeneous catalysts with outstanding solar-light-driven photocatalytic properties were obtained.

Thermally activated delayed fluorescence materials with aggregation-induced emission properties: a QM/MM study.

Organic molecules with thermally activated delayed fluorescence (TADF) and aggregation induced emission (AIE) properties have attracted increasing research interest due to their great potential applications in organic light emitting diodes (OLEDs), especially for those with multicolor mechanochromic luminescence (MCL) features. Theoretical research on the luminescence characteristics of organic TADF emitters based on the aggregation states is highly desired to quantify the relationship between the TADF properties and aggregation states. In this work, we study the 4,4'-(6-(9,9-dimethylacridine-10(9H)-yl)quinoline-2,3-dibenzonitrile (DMAC-CNQ) emitter with TADF and AIE properties, and calculate the photophysical properties in gas, solid and amorphous states by using the quantum mechanics and molecular mechanics (QM/MM) method. Our simulations demonstrate that the aggregation states enhance obviously the reverse intersystem crossing rates and transition dipole moments of the DMAC-CNQ emitter, and suppress the non-radiative rates from the lowest excited singlet state (S1) to ground state (S0). Specifically, the molecular stacking of DMAC-CNQ in solid phases can mainly restrict the geometric torsion of the DMAC moiety for decreasing non-radiative decay rates, and the torsion of the CNQ moiety for increasing the reverse intersystem crossing rates. As a result, the calculated fluorescence efficiencies of the DMAC-CNQ emitter in the crystal and amorphous states are 67% and 26% respectively, and in good agreement with the experimental results.

Chiral Discrimination by a Binuclear Pd Complex Sensor Using 31P{1H} NMR.

An axially chiral binuclear µ-hydroxo Pd complex (BPHP) first served as an excellent chiral sensor for discriminating a variety of analytes including amino alcohol, amino amide, amino acid, mandelic acid, diol, diamine, and monoamine by 31P{1H} NMR. A detailed recognition mechanism was proposed based on the single crystal and mass spectrum of Pd-complexes. In general, BPHP sensor, through extracting the acidic hydrogen of an analyte by its Pd-OH group, forms stable diastereomeric complexes with two enantiomers of the analyte giving well distinguishable split 31P{1H} NMR signals for chiral discrimination.

Synergistic Intra- and Intermolecular Noncovalent Interactions for Ultralong Organic Phosphorescence.

Metal-free ultralong organic phosphorescence (UOP) materials have attracted significant attention owing to their anomalous photophysical properties and potential applications in various fields. Here, three pyrimidine-based organic luminogens, 9-(pyrimidin-2-yl)-9H-carbazole, 9-(4,6-dimethylpyrimidin-2-yl)-9H-carbazole, and 9-(5-bromopyrimidin-2-yl)-9H-carbazole are designed and synthesized, which show efficient yellow UOP with the longest lifetimes up to 1.37 s and the highest absolute phosphorescence quantum yields up to 23.6% under ambient conditions. Theoretical calculations, crystal structures, and photophysical properties of these compounds reveal that intramolecular hydrogen bonding, intermolecular π-π interactions, and intermolecular electronic coupling are responsible for forming dimers and generating highly efficient UOP. Their efficacy as solid materials for data encryption is demonstrated.

Live birth derived from oocyte spindle transfer to prevent mitochondrial disease.

Mutations in mitochondrial DNA (mtDNA) are maternally inherited and can cause fatal or debilitating mitochondrial disorders. The severity of clinical symptoms is often associated with the level of mtDNA mutation load or degree of heteroplasmy. Current clinical options to prevent transmission of mtDNA mutations to offspring are limited. Experimental spindle transfer in metaphase II oocytes, also called mitochondrial replacement therapy, is a novel technology for preventing mtDNA transmission from oocytes to pre-implantation embryos. Here, we report a female carrier of Leigh syndrome (mtDNA mutation 8993T > G), with a long history of multiple undiagnosed pregnancy losses and deaths of offspring as a result of this disease, who underwent IVF after reconstitution of her oocytes by spindle transfer into the cytoplasm of enucleated donor oocytes. A male euploid blastocyst wasobtained from the reconstituted oocytes, which had only a 5.7% mtDNA mutation load. Transfer of the embryo resulted in a pregnancy with delivery of a boy with neonatal mtDNA mutation load of 2.36-9.23% in his tested tissues. The boy is currently healthy at 7 months of age, although long-term follow-up of the child's longitudinal development remains crucial.

Combining Charge-Transfer Pathways to Achieve Unique Thermally Activated Delayed Fluorescence Emitters for High-Performance Solution-Processed, Non-doped Blue OLEDs.

Two efficient blue thermally activated delayed fluorescence compounds, B-oCz and B-oTC, composed of ortho-donor (D)-acceptor (A) arrangement were designed and synthesized. The significant intramolecular D-A interactions induce a combined charge transfer pathway and thus achieve small ΔEST and high efficiencies. The concentration quenching can be effectively inhibited in films of these compounds. The blue non-doped organic light emitting diodes (OLEDs) based on B-oTC prepared from solution processes shows record-high external quantum efficiency (EQE) of 19.1 %.

Minimal stimulation IVF vs conventional IVF: a randomized controlled trial.

BACKGROUND: Minimal stimulation in vitro fertilization (mini-in vitro fertilization) is an alternative in vitro fertilization treatment protocol that may reduce ovarian hyperstimulation syndrome, multiple pregnancy rates, and cost while retaining high live birth rates. OBJECTIVE: We performed a randomized noninferiority controlled trial with a prespecified border of 10% that compared 1 cycle of mini-in vitro fertilization with single embryo transfer with 1 cycle of conventional in vitro fertilization with double embryo transfer. STUDY DESIGN: Five hundred sixty-four infertile women (<39 years old) who were undergoing their first in vitro fertilization cycle were allocated randomly to either mini-in vitro fertilization or conventional in vitro fertilization. The primary outcome was cumulative live birth rate per woman over a 6-month period. Secondary outcomes included ovarian hyperstimulation syndrome, multiple pregnancy rates, and gonadotropin use. The primary outcome was cumulative live birth per randomized woman within a time horizon of 6 months. RESULTS: Five hundred sixty-four couples were assigned randomly between February 2009 and August 2013 with 285 couples allocated to mini-in vitro fertilization and 279 couples allocated to conventional in vitro fertilization. The cumulative live birth rate was 49% (140/285) for mini-in vitro fertilization and 63% (176/279) for conventional in vitro fertilization (relative risk, 0.76; 95% confidence interval, 0.64-0.89). There were no cases of ovarian hyperstimulation syndrome after mini-in vitro fertilization compared with 16 moderate/severe ovarian hyperstimulation syndrome cases (5.7%) after conventional in vitro fertilization. The multiple pregnancy rates were 6.4% in mini-in vitro fertilization compared with 32% in conventional in vitro fertilization (relative risk, 0.25; 95% confidence interval, 0.14-0.46). Gonadotropin consumption was significantly lower with mini-in vitro fertilization compared with conventional in vitro fertilization (459 ± 131 vs 2079 ± 389 IU; P < .0001). CONCLUSION: Compared with conventional in vitro fertilization with double embryo transfer, mini-in vitro fertilization with single embryo transfer lowers live birth rates, completely eliminates ovarian hyperstimulation syndrome, reduces multiple pregnancy rates, and reduces gonadotropin consumption.

Autologous oocyte cryopreservation in women aged 40 and older using minimal stimulation IVF.

BACKGROUND: The value of oocyte cryopreservation in older women remains controversial. The aim of this study was to report the oocyte freezing experience in women aged 40 and older at a single fertility center. FINDINGS: One hundred fifty eight women (mean age 43.9 ± 0.2) who underwent minimal ovarian stimulation IVF were enrolled. IVF protocol included the use of clomiphene citrate (50 mg/day) or letrozole (2.5 mg/day) with or without low dose gonadotropins (started at 75 IU/day and increased as needed to 150 IU/day). 584 retrieved oocytes (2.1 ± 0.15 per patient) yielded 532 mature MII oocytes that were frozen. After thawing and fertilization by ICSI, a total of 344 embryos (1.9 ± 0.1 per patient) were formed. A total of 57 relatively good embryos were transferred and yielded three live births (5.3 % per embryo transfer), three spontaneous abortions, and one chemical pregnancy. CONCLUSIONS: These data are important in counseling older women who desire autologous oocyte freezing.

Obesity adversely impacts the number and maturity of oocytes in conventional IVF not in minimal stimulation IVF.

OBJECTIVE: The objective of this study was to assess the relationship between BMI and oocyte number and maturity in participants who underwent minimal stimulation (mini-) or conventional IVF. METHODS: Participants who underwent their first autologous cycle of either conventional (n = 219) or mini-IVF (n = 220) were divided according to their BMI to analyze IVF outcome parameters. The main outcome measure was the number of oocytes in metaphase II (MII). Secondary outcomes included the number of total oocytes retrieved, fertilized (2PN) oocytes, cleavage and blastocyst stage embryos, clinical pregnancy (CP), and live birth (LB) rates. RESULTS: In conventional IVF, but not in mini-IVF, the number of total oocytes retrieved (14.5 ± 0.8 versus 8.8 ± 1.3) and MII oocytes (11.2 ± 0.7 versus 7.1 ± 1.1) were significantly lower in obese compared with normal BMI women. Multivariable linear regression adjusting for age, day 3 FSH, days of stimulation, and total gonadotropin dose demonstrated that BMI was an independent predictor of the number of MII oocytes in conventional IVF (p = 0.0004). Additionally, only in conventional IVF, BMI was negatively correlated with the total number of 2PN oocytes, as well as the number of cleavage stage embryos. CONCLUSIONS: Female adiposity might impair oocyte number and maturity in conventional IVF but not in mini-IVF. These data suggest that mild ovarian stimulation might yield healthier oocytes in obese women.

Rotational isomerization: spontaneous structural transformation of a thermally activated delayed fluorescence binuclear copper(I) complex.

A novel binuclear Cu(I) halide complex, Cu2I2(DPPCz)2, which emits efficient thermally activated delayed fluorescence (TADF), is reported. The crystal of this complex spontaneously undergoes ligand rotation and coordination-configuration transformation, converting to its isomer without any external stimulation.

miR-153-3p via PIK3R1 Is Involved in Cigarette Smoke-Induced Neurotoxicity in the Brain.

Cigarettes contain various chemicals that cause damage to nerve cells. Exposure to cigarette smoke (CS) causes insulin resistance (IR) in nerve cells. However, the mechanisms for a disorder in the cigarette-induced insulin signaling pathway and in neurotoxicity remain unclear. Therefore, we evaluated, by a series of pathology analyses and behavioral tests, the neurotoxic effects of chronic exposure to CS on C57BL/6 mice. Mice exposed to CS with more than 200 mg/m3 total particulate matter (TPM) exhibited memory deficits and cognitive impairment. Pathological staining of paraffin sections of mouse brain tissue revealed that CS-exposed mice had, in the brain, neuronal damage characterized by thinner pyramidal and granular cell layers and fewer neurons. Further, the exposure of SH-SY5Y cells to cigarette smoke extract (CSE) resulted in diminished insulin sensitivity and reduced glucose uptake in a dose-dependent fashion. The PI3K/GSK3 insulin signaling pathway is particularly relevant to neurotoxicity. microRNAs are involved in the PI3K/GSK3ß/p-Tau pathway, and we found that cigarette exposure activates miR-153-3p, decreases PI3K regulatory subunits PIK3R1, and induces Tau hyperphosphorylation. Exposure to an miR-153 inhibitor or to a PI3K inhibitor alleviated the reduced insulin sensitivity caused by CS. Therefore, our results indicate that miR-153-3p, via PIK3R1, causes insulin resistance in the brain, and is involved in CS-induced neurotoxicity.

Efficiently increasing the radiative rate of TADF material with metal coordination.

Herein, a simple and straightforward method to reduce dramatically the lifetime of a pure organic thermally activated delayed fluorescence (TADF) material VIA metal coordination is demonstrated. We designed a mononuclear silver complex [Ag(PPh2CH3)(TCzBN-PyPz)]BF4 (1) with a new emissive TCzBN-PyPz ligand. Even though the ligand and the metal complex have very similar emissive efficiencies and maximal peaks, over three orders of magnitude shorter lifetime of 0.59 µs for the complex than 2074 µs for ligand were obtained. Compared to other methods, the present protocol seems to be simple and highly effective.

Correction: Efficiently increasing the radiative rate of TADF material with metal coordination.

Correction for 'Efficiently increasing the radiative rate of TADF material with metal coordination' by Xian-Bao Cai et al., Chem. Commun., 2022, 58, 8970-8973, https://doi.org/10.1039/D2CC02930H.

Voltage-Dependent Emission Varying from Blue to Orange-Red from a Nondoped Organic Light-Emitting Diode with a Single Emitter.

Organic light-emitting diodes (OLEDs) with tunable emission colors, especially white OLEDs, have rarely been observed with a single emitter in a single emissive layer. In this paper, we report a new compound featuring a D-A-D structure, 9,9'-(pyrimidine-2,5-diylbis(2,1-phenylene))bis(3,6-di-tert-butyl-9H-carbazole) (PDPC). A nondoped OLED using this compound as a single emitter exhibits unique voltage-dependent dual emission. The emission colors range from blue to orange-red with an increase in voltage, during which white electroluminescence with a Commission Internationale De L'Eclairage (CIE) coordinate of (0.35, 0.29) and a color render index (CRI) value of 93 was observed. A comparative study revealed that the dual emission simultaneously originates from the monomers and excimers of the emitter. This study provides insight into understanding the multimer-excited mechanism and developing novel color-tunable OLEDs.

Dynamics in two interacting subpopulations of nonidentical phase oscillators.

Chimera states refer to the dynamical states in which the inherent symmetry of the system is broken. The system composed of two interacting identical subpopulations of phase oscillators provides a platform to study chimera states. In this system, different types of chimera states have been identified and the transitions between them have been investigated. However, the parameter space is not fully explored in this system. In this work, we study a system comprised of two interacting subpopulations of nonidentical phase oscillators. Through numerical simulations and theoretical analyses, we find three symmetry-reserving states, including incoherent state, in-phase synchronous state, and antiphase synchronous state, and three types of symmetry-breaking states, including in-phase chimera states, antiphase chimera states, and weak chimera states. The stability diagrams of these dynamical states are explored on different parameter planes and transition scenarios amongst these states are investigated. We find that the weak chimera states act as the bridge between in-phase and antiphase chimera states. We also observe the existence of a period-two chimera state, chaotic chimera state, and drifting chimera states.

Bright bluish-green emitting Cu(I) complexes exhibiting efficient thermally activated delayed fluorescence.

Three strongly emissive Cu(i) complexes [Cu(tBupzmpy)(POP)]BF4(1), [Cu(Phpzmpy)(POP)]BF4(2) and [Cu(Adpzmpy)(POP)]BF4(3) (tBupzmpy = 2-(5-(tert-butyl)-1H-pyrazol-3-yl)-6-methylpyridine, Phpzmpy = 2-methyl-6-(5-phenyl-1H-pyrazol-3-yl)pyridine, Adpzmpy = 2-(5-((3R,5R)-adamantan-1-yl)-1H-pyrazol-3-yl)-6-methylpyridine, and POP = bis[2-(diphenylphosphino)phenyl]ether) were synthesized and characterized. These complexes exhibit bright bluish-green photoluminescence in the solid state with quantum yields of 91% (1), 71% (2) and 77% (3) and lifetimes of 13.4 µs (1), 32.9 µs (2) and 34.1 µs (3) at room temperature. The results of theoretical calculations, coupled with the temperature dependence of the spectroscopic properties and emission decay behaviors, reveal that the title Cu(i) complexes emit efficient thermally activated delayed fluorescence (TADF) from excited states involving metal-to-ligand charge transfer (MLCT) transitions and ligand-to-ligand charge transfer (LLCT) transitions. The emissive-state characteristics and emission properties of the investigated Cu(i) complexes were tuned effectively by changing the steric and electronic structures of the diimine ligands.

Keyword spotting techniques to improve the recognition accuracy of user-defined keywords.

The existing keyword spotting (KWS) techniques can recognize pre-defined keywords well but have a poor recognition accuracy for user-defined keywords. In real use cases, there is a high demand for users to define their keywords for various reasons. To address the problem, in this work, three techniques have been proposed, including incremental training with revised loss function, data augmentation, and fine-grained training, to improve the accuracy for the user-defined keywords while maintaining high accuracy for pre-defined keywords. The proposed techniques are applied to a classical KWS model (cnn-trad-fpool3) and a state-of-the-art KWS model (res15) respectively. The experimental results show that the proposed techniques have better recognition accuracy than several existing methods for the recognition of use-defined keywords. With the proposed techniques, the recognition accuracy of user-defined keywords on cnn-trad-fpool3 and res15 are significantly improved by 21.78% and 24.42%, respectively.