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1.
Langmuir ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38332611

RESUMO

An asymmetric structure is an important strategy for designing highly conductive molecular wires for a gap-fixed molecular circuit. As the conductance enhancement in the current strategy is still limited to about 2 times, we inserted a methylene group as a spacer in a conjugated structure to modulate the structural symmetry. We found that the conductance drastically enhanced in the asymmetric molecular wire to 1.5 orders of magnitude as high as that in the symmetric molecular wire. First-principles quantum transport studies attributed the effective enhancement to the synchronization of improved energy alignment and nearly symmetric coupling between the frontier orbitals and the electrodes.

2.
Ecotoxicol Environ Saf ; 277: 116363, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38663190

RESUMO

Environmental aflatoxin B1 (AFB1) exposure has been proposed to contribute to hepatocellular carcinoma by promoting liver fibrosis, but the potential mechanisms remain to be further elucidated. Extracellular vesicles (EVs) were recognized as crucial traffickers for hepatic intercellular communication and play a vital role in the pathological process of liver fibrosis. The AFB1-exposed hepatocyte-derived EVs (AFB1-EVs) were extracted, and the functional effects of AFB1-EVs on the activation of hepatic stellate cells (HSCs) were explored to investigate the molecular mechanism of AFB1 exposure-induced liver fibrogenesis. Our results revealed that an environment-level AFB1 exposure induced liver fibrosis via HSCs activation in mice, while the AFB1-EVs mediated hepatotoxicity and liver fibrogenesis in vitro and in vivo. AFB1 exposure in vitro increased PINK1/Parkin-dependent mitophagy in hepatocytes, where upregulated transcription of the PARK2 gene via p53 nuclear translocation and mitochondrial recruitment of Parkin, and promoted AFB1-EVs-mediated mitochondria-trafficking communication between hepatocytes and HSCs. The knockdown of Parkin in HepaRG cells reversed HSCs activation by blocking the mitophagy-related AFB1-EVs trafficking. This study further revealed that the hepatic fibrogenesis of AFB1 exposure was rescued by genetic intervention with siPARK2 or p53's Pifithrin-α (PFTα) inhibitors. Furthermore, AFB1-EVs-induced HSCs activation was relieved by GW4869 pharmaceutic inhibition of EVs secretion. These results revealed a novel mechanism that AFB1 exposure-induced p53-Parkin signal axis regulated mitophagy-dependent hepatocyte-derived EVs to mediate the mitochondria-trafficking intercellular communication between hepatocytes and HSCs in the local hepatotoxic microenvironment to promote the activated HSCs-associated liver fibrogenesis. Our study provided insight into p53-Parkin-dependent pathway regulation and promised an advanced strategy targeting intervention to EVs-mediated mitochondria trafficking for preventing xenobiotics-induced liver fibrosis.


Assuntos
Aflatoxina B1 , Vesículas Extracelulares , Células Estreladas do Fígado , Hepatócitos , Cirrose Hepática , Mitofagia , Proteína Supressora de Tumor p53 , Ubiquitina-Proteína Ligases , Aflatoxina B1/toxicidade , Cirrose Hepática/induzido quimicamente , Cirrose Hepática/patologia , Vesículas Extracelulares/efeitos dos fármacos , Vesículas Extracelulares/metabolismo , Mitofagia/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/patologia , Células Estreladas do Fígado/efeitos dos fármacos , Células Estreladas do Fígado/metabolismo , Animais , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Camundongos , Masculino , Humanos , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacos
3.
BMC Med Educ ; 24(1): 461, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38671399

RESUMO

BACKGROUND: 3D visualization technology applies computers and other devices to create a realistic virtual world for individuals with various sensory experiences such as 3D vision, touch, and smell to gain a more effective understanding of the relationships between real spatial structures and organizations. The purpose of this study was to comprehensively evaluate the effectiveness of 3D visualization technology in human anatomy teaching/training and explore the potential factors that affect the training effects to better guide the teaching of classroom/laboratory anatomy. METHODS: We conducted a meta-analysis of randomized controlled studies on teaching human anatomy using 3D visualization technology. We extensively searched three authoritative databases, PubMed, Web of Science, and Embase; the main outcomes were the participants' test scores and satisfaction, while the secondary outcomes were time consumption and enjoyment. Heterogeneity by I² was statistically determined because I²> 50%; therefore, a random-effects model was employed, using data processing software such as RevMan, Stata, and VOSviewer to process data, apply standardized mean difference and 95% confidence interval, and subgroup analysis to evaluate test results, and then conduct research through sensitivity analysis and meta-regression analysis. RESULTS: Thirty-nine randomized controlled trials (2,959 participants) were screened and included in this study. The system analysis of the main results showed that compared with other methods, including data from all regions 3D visualization technology moderately improved test scores as well as satisfaction and enjoyment; however, the time that students took to complete the test was not significantly reduced. Meta-regression analysis also showed that regional factorsaffected test scores, whereas other factors had no significant impact. When the literature from China was excluded, the satisfaction and happiness of the 3D virtual-reality group were statistically significant compared to those of the traditional group; however, the test results and time consumption were not statistically significant. CONCLUSION: 3D visualization technology is an effective way to improve learners' satisfaction with and enjoyment of human anatomical learning, but it cannot reduce the time required for testers to complete the test. 3D visualization technology may struggle to improve the testers' scores. The literature test results from China are more prone to positive results and affected by regional bias.


Assuntos
Anatomia , Imageamento Tridimensional , Estudantes de Medicina , Humanos , Anatomia/educação , Estudantes de Medicina/psicologia , Internato e Residência , Ensaios Clínicos Controlados Aleatórios como Assunto , Realidade Virtual , Análise de Regressão , Instrução por Computador/métodos
4.
Dig Endosc ; 36(2): 141-151, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37059698

RESUMO

OBJECTIVES: Subepithelial lesions (SELs) are associated with various endoscopic resection (ER) outcomes and diagnostic challenges. We aimed to establish a tool for predicting ER-related outcomes and diagnosing SELs and to investigate the predictive value of endoscopic ultrasound (EUS). METHODS: Phase 1 (system development) was performed in a retrospective cohort (n = 837) who underwent EUS before ER for SELs at eight hospitals. Prediction models for five key outcomes were developed using logistic regression. Models with satisfactory internal validation performance were included in a mobile application system, SEL endoscopic resection predictor (SELERP). In Phase 2, the models were externally validated in a prospective cohort of 200 patients. RESULTS: An SELERP was developed using EUS characteristics, which included 10 models for five key outcomes: post-ER ulcer management, short procedure time, long hospital stay, high medication costs, and diagnosis of SELs. In Phase 1, 10 models were derived and validated (C-statistics, 0.67-0.99; calibration-in-the-large, -0.14-0.10; calibration slopes, 0.92-1.08). In Phase 2, the derived risk prediction models showed convincing discrimination (C-statistics, 0.64-0.73) and calibration (calibration-in-the-large, -0.02-0.05; calibration slopes, 1.01-1.09) in the prospective cohort. The sensitivities and specificities of the five diagnostic models were 68.3-95.7% and 64.1-83.3%, respectively. CONCLUSION: We developed and prospectively validated an application system for the prediction of ER outcomes and diagnosis of SELs, which could aid clinical decision-making and facilitate patient-physician consultation. EUS features significantly contributed to the prediction. TRIAL REGISTRATION: Chinese Clinical Trial Registry, http://www.chictr.org.cn (ChiCTR2000040118).


Assuntos
Aspiração por Agulha Fina Guiada por Ultrassom Endoscópico , Endossonografia , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Endossonografia/métodos , Sensibilidade e Especificidade
5.
Nano Lett ; 23(20): 9399-9405, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37877237

RESUMO

An accurate rule for predicting conductance is the cornerstone of developing molecular circuits and provides a promising solution for miniaturizing electric circuits. The successful prediction of series molecular circuits has proven the possibility of establishing a rule for molecular circuits under quantum mechanics. However, the quantitatively accurate prediction has not been validated by experiments for parallel molecular circuits. Here we used 1,3-dihydrobenzothiophene (DBT) to build the parallel molecular circuits. The theoretical simulation and single-molecule conductance measurements demonstrated that the conductance of the molecule containing one DBT is the unprecedented linear combination of the conductance of the two individual channels with respective contribution weights of 0.37 and 0.63. With these weights, the conductance of the molecule containing two DBTs is predicted as 1.81 nS, matching perfectly with the measured conductance (1.82 nS). This feature offers a potential rule for quantitatively predicting the conductance of parallel molecular circuits.

6.
Molecules ; 29(6)2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38542856

RESUMO

Coordination cages sustained by metal-ligand interactions feature polyhedral architectures and well-defined hollow structures, which have attracted significant attention in recent years due to a variety of structure-guided promising applications. Sulfonylcalix[4]arenes-based coordination cages, termed metal-organic supercontainers (MOSCs), that possess unique multi-pore architectures containing an endo cavity and multiple exo cavities, are emerging as a new family of coordination cages. The well-defined built-in multiple binding domains of MOSCs allow the efficient encapsulation of guest molecules, especially for drug delivery. Here, we critically discuss the design strategy, and, most importantly, the recent advances in research surrounding cavity-specified host-guest chemistry and biomedical applications of MOSCs.

7.
Molecules ; 29(11)2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38893316

RESUMO

For designing single-molecule devices that have both conjugation systems and structural flexibility, a hyperconjugated molecule with a σ-π bond interaction is considered an ideal candidate. In the investigation of conductance at the single-molecule level, since few hyperconjugation systems have been involved, the strategy of building hyperconjugation systems and the mechanism of electron transport within this system remain unexplored. Based on the skipped-conjugated structure, we present a rational approach to construct a hyperconjugation molecule using a hydroxyl group, which serves as a bridge to interact with the conjugated fragments. The measurement of single-molecule conductance reveals a two-fold conductance enhancement of the hyperconjugation system having the 'bridging' hydroxyl group compared to hydroxyl-free derivatives. Theoretical studies demonstrate that the hydroxyl group in the hyperconjugation system connects the LUMO of the two conjugated fragments and opens a through-space channel for electron transport to enhance the conductance.

8.
Chromosoma ; 131(1-2): 87-105, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35437661

RESUMO

Timely and accurate centrosome separation is critical for bipolar spindle organization and faithful chromosome segregation during cell division. Kinesin-5 Eg5 is essential for centrosome separation and spindle organization in somatic cells; however, the detailed functions and mechanisms of Eg5 in spermatocytes remain unclear. In this study, we show that Eg5 proteins are located at spindle microtubules and centrosomes in spermatocytes both in vivo and in vitro. We reveal that the spermatocytes are arrested at metaphase I in seminiferous tubules after Eg5 inhibition. Eg5 ablation results in cell cycle arrest, the formation of monopolar spindle, and chromosome misalignment in cultured GC-2 spd cells. Importantly, we find that the long-term inhibition of Eg5 results in an increased number of centrosomes and chromosomal instability in spermatocytes. Our findings indicate that Eg5 mediates centrosome separation to control spindle assembly and chromosome alignment in spermatocytes, which finally contribute to chromosome stability and faithful cell division of the spermatocytes.


Assuntos
Cinesinas , Fuso Acromático , Centrossomo/metabolismo , Humanos , Cinesinas/genética , Masculino , Microtúbulos/metabolismo , Espermatócitos , Fuso Acromático/metabolismo
9.
Inorg Chem ; 62(47): 19323-19331, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37955402

RESUMO

Diradicaloids are generally high-energy molecules with open-shell configuration and are quite reactive. In this work, we report a feasible synthetic approach to attaining exceptionally stable copper(I) metallacyclopentadiene diradicaloids through ligand engineering. Copper(I)-hybrid cyclopentadiene diradicaloids 1c-6c that absorb intensely in visible regions were successfully prepared in stoichiometrical yields under UV light irradiation. The diradicaloids originate from the C-C bonding coupling of two side-by-side-arranged ethynyl groups in complexes 1-6 upon photocyclization. By rational selection of substituents in triphosphine ligands, we systematically modulate the kinetic behavior of diradicaloids 1c-6c in the thermal decoloration process. With precise ligand design, we are able to obtain exceptionally stable copper(I)-hybrid cyclopentadiene diradicaloids with a half-life as long as ca. 40 h in CH2Cl2 solution at ambient temperature. As demonstrated by electron paramagnetic resonance (EPR) and variable-temperature magnetic studies, the diradicaloids manifest a singlet ground state, but they are readily populated to a triplet excited state through thermal activation in view of a small singlet-triplet energy gap of -0.39 kcal mol-1. The diradicaloids show two-step quasi-reversible reduction waves at about -0.5 and -1.0 V ascribed to successive one-electron-accepting processes, coinciding perfectly with the characteristics of diradicals.

10.
Mol Biol Rep ; 50(1): 655-664, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36371556

RESUMO

BACKGROUND: Identification of the risk factors for atrophic gastritis (AG) and prevention of further deterioration of the gastritis are effective approaches to reduce the incidence of gastric cancer. Previous studies found that dysbiosis has been implicated in a wide range of diseases, while the role of gastric bacteria as a biomarker for AG has not been explored. METHODS AND RESULTS: Gastric juices from cases with non-atrophic gastritis (NAG) and AG were collected for investigation of bacterial composition and function. The ß-diversity of microbiota exhibited a significant reduction in AG samples compared with that in NAG samples. Differential abundance analysis revealed that a total of 23 predicted species changed their distributions; meanwhile, all obligate anaerobic bacteria with a relatively high abundance lowered their contents in AG samples. Additionally, the correlation analysis indicated a clear shift in bacterial correlation pattern between the two groups. Functional interrogation of the gastric microbiota showed that bacterial metabolisms associated with enzyme families, digestive system, and endocrine system were downregulated in AG samples. The compositional dissection of "core microbiota" exhibited that oral pathogens, including Porphyromonas gingivalis, Campylobacter gracilis, and Granulicatella elegans, were magnified in AG samples, suggesting that oral diseases may be a trigger factor for early exacerbation of gastritis. Then, the differentially expressed bacteria were used as diagnostic biomarkers for the random forest classifier model for group prediction. CONCLUSIONS: The results showed that bacterial biomarkers could distinguish AG patients from NAG cases with an accuracy of 90% at the genus level.


Assuntos
Gastrite Atrófica , Gastrite , Infecções por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Humanos , Gastrite Atrófica/diagnóstico , Neoplasias Gástricas/microbiologia , Biomarcadores , Bactérias , Infecções por Helicobacter/microbiologia
11.
J Gastroenterol Hepatol ; 38(6): 962-969, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37094943

RESUMO

BACKGROUND AND AIM: Lugol chromoendoscopy is the standard technique to detect an esophageal squamous cell carcinoma (ESCC). However, a high concentration of Lugol's solution can induce mucosal injury and adverse events. We aimed to investigate the optimal concentration of Lugol's solution to reduce mucosal injury and adverse events without degrading image quality. METHODS: This was a two-phase double-blind randomized controlled trial. In phase I, 200 eligible patients underwent esophagogastroduodenoscopy and then were randomly (1:1:1:1:1) sprayed with 1.2%, 1.0%, 0.8%, 0.6%, or 0.4% Lugol's solution. Image quality, gastric mucosal injury, adverse events, and operation satisfaction were compared to investigate the minimal effective concentration. In phase II, 42 cases of endoscopic mucosectomy for early ESCC were included. The patients were randomly assigned (1:1) to the minimal effective (0.6%) or conventional (1.2%) concentration of Lugol's solution for further comparison of the effectiveness. RESULTS: In phase I, the gastric mucosal injury was significantly reduced in 0.6% group (P < 0.05). Furthermore, there was no statistical significance in image quality between 0.6% and higher concentrations of Lugol's solution (P > 0.05, respectively). It also showed that the operation satisfaction decreased in 1.2% group compared with the lower concentration groups (P < 0.05). In phase II, the complete resection rate was 100% in both groups, while 0.6% Lugol's solution showed higher operation satisfaction (W = 554.500, P = 0.005). CONCLUSIONS: The study indicates that 0.6% might be the optimal concentration of Lugol's solution for early detection and delineation of ESCC, considering minimal mucosal injury and satisfied image. The registry of clinical trials: ClinicalTrials.gov (NCT03180944).


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Neoplasias Esofágicas/patologia , Esofagoscopia/métodos , Corantes
12.
Environ Res ; 216(Pt 2): 114571, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36243047

RESUMO

Few epidemiological studies have focused on prenatal phthalates (PAEs) and polybrominated diphenyl ethers (PBDEs) exposure to neonatal health in China. This study aimed to assess the associations between prenatal PAEs and PBDEs exposure and neonatal health in Guangxi, a Zhuang autonomous region of China. Concentrations of 4 PAEs metabolites (mPAEs) and 5 PBDEs congeners were measured in the serum of 267 healthy pregnant women. Birth outcomes and clinical data of neonates were collected after delivery. Mono-(2-Ethylhexyl) phthalate (MEHP) (81.52%) and BDE47 (35.21%) were the mPAEs and PBDEs congeners with the highest detection rate in serum. Prenatal exposures to mono-n-butyl phthalate (MBP), MEHP, and ΣmPAEs were negatively associated with birth weight (BW), birth length (BL), and gestational age (GA). Higher exposures to MBP, MEHP, and ΣmPAEs were associated with an increased odds ratio (OR) for low birth weight (LBW), but exposure to BDE28 exhibited the opposite effect. Moreover, higher exposures to MBP, MEHP, ΣmPAEs, BDE99, and ΣPBDEswere associated with an increased OR for premature birth (PTB) (P < 0.05). In contrast to MBP exposure, BDE28 exposure was associated with a higher OR for neonatal jaundice (NNJ) (P < 0.05). The interaction analysis showed a positive interaction between monoethyl phthalate (MEP) and BDE28 on the risk of NNJ and positive interaction between ΣmPAEs and BDE47 on the risk of NNJ. In addition, there are ethnicity-specific associations of prenatal PBDEs exposure with neonatal health in individuals of Zhuang and Han nationalities, and boy neonates were more sensitive to prenatal PBDEs exposure than girl neonates. The results revealed that prenatal exposure to mPAEs and PBDEs might have adverse effects on neonatal development, and the effects might be ethnicity- and sex-specific.


Assuntos
Ácidos Ftálicos , Efeitos Tardios da Exposição Pré-Natal , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez , Coorte de Nascimento , China/epidemiologia , Estudos de Coortes , Éteres Difenil Halogenados/toxicidade , Saúde do Lactente , Exposição Materna/efeitos adversos , Ácidos Ftálicos/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/epidemiologia
13.
J Plant Res ; 136(3): 413-421, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36826610

RESUMO

Uranium (U) phytotoxicity is an inherently difficult problem in the phytoremediation of U-contaminated environments. Plant chelating and antioxidant systems play an authoritative role in resistance to abiotic stress. To reveal the toxicity of U, the changes of chelating system, osmoregulatory substances and antioxidant systems in Vicia faba roots were studied after short-term (24 h) U exposure. The results indicated that the development of lateral roots and root activity of V. faba were significantly inhibited with U accumulation. Compared with the control, plant chelating systems showed significant positive effects after U exposure (15 - 25 µM). Osmoregulatory substances (proline and soluble protein) increasingly accumulated in roots with increasing U concentration, and O2- and H2O2 rapidly accumulated after U exposure (15 - 25 µM). Thus, the contents of malondialdehyde (MDA), a marker of lipid peroxidation, were also significantly increased. Antioxidant systems were activated after U exposure but were inhibited at higher U concentrations (15 - 25 µM). In summary, although the chelating, osmotic regulation and antioxidant systems in V. faba were activated after short-term U exposure, the antioxidases (CAT, SOD and POD) were inhibited at higher U concentrations (15 - 25 µM). Therefore, the root cells were severely damaged by peroxidation, which eventually resulted in inhibited activity and arrested root development.


Assuntos
Poluentes Radioativos do Solo , Urânio , Vicia faba , Antioxidantes/metabolismo , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo , Raízes de Plantas/metabolismo , Urânio/metabolismo , Urânio/toxicidade , Vicia faba/metabolismo , Vicia faba/efeitos da radiação
14.
Sensors (Basel) ; 23(17)2023 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-37687962

RESUMO

Mobile sensors can extend the range of monitoring and overcome static sensors' limitations and are increasingly used in real-life applications. Since there can be significant errors in mobile sensor localization using the Monte Carlo Localization (MCL), this paper improves the food digestion algorithm (FDA). This paper applies the improved algorithm to the mobile sensor localization problem to reduce localization errors and improve localization accuracy. Firstly, this paper proposes three inter-group communication strategies to speed up the convergence of the algorithm based on the topology that exists between groups. Finally, the improved algorithm is applied to the mobile sensor localization problem, reducing the localization error and achieving good localization results.

15.
Int J Mol Sci ; 24(5)2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36901737

RESUMO

Since the discovery of fluorescent proteins (FPs), their rich fluorescence spectra and photochemical properties have promoted widespread biological research applications. FPs can be classified into green fluorescent protein (GFP) and its derivates, red fluorescent protein (RFP) and its derivates, and near-infrared FPs. With the continuous development of FPs, antibodies targeting FPs have emerged. The antibody, a class of immunoglobulin, is the main component of humoral immunity that explicitly recognizes and binds antigens. Monoclonal antibody, originating from a single B cell, has been widely applied in immunoassay, in vitro diagnostics, and drug development. The nanobody is a new type of antibody entirely composed of the variable domain of a heavy-chain antibody. Compared with conventional antibodies, these small and stable nanobodies can be expressed and functional in living cells. In addition, they can easily access grooves, seams, or hidden antigenic epitopes on the surface of the target. This review provides an overview of various FPs, the research progress of their antibodies, particularly nanobodies, and advanced applications of nanobodies targeting FPs. This review will be helpful for further research on nanobodies targeting FPs, making FPs more valuable in biological research.


Assuntos
Anticorpos de Domínio Único , Anticorpos Monoclonais , Antígenos , Proteínas de Fluorescência Verde/metabolismo , Cadeias Pesadas de Imunoglobulinas/química , Proteína Vermelha Fluorescente
16.
Molecules ; 28(7)2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-37050014

RESUMO

Reaction of [Au(tht)2](ClO4) (tht = tetrahydrothiophene), [Cu(CH3CN)4](ClO4), 3,6-di-tert-butyl-1,8-diethynyl-9H-carbazole (H3decz), and bis(2-diphenylphosphinophenyl)ether (POP) in the presence of triethylamine (NEt3) gave the cluster complex Au4Cu2(decz)2(POP)2 as yellow crystals. As revealed by X-ray crystallography, the Au4Cu2 cluster exhibits scissor-like structure sustained by two decz and two POP ligands and stabilized by Au-Cu and Au-Au interactions. The Au4Cu2 cluster shows bright yellow to orange photoluminescence upon irradiation at >300 nm, arising from 3[π (decz)→5d (Au)] 3LMCT (ligand-to-metal charge transfer) and 3[π→π* (decz)] 3IL (intraligand) triplet states as revealed by theoretical and computational studies. When it is mechanically ground, reversible phosphorescence conversion from yellow to red is observed owing to more compact molecular packing and thus stronger intermetallic interaction. Variable-temperature luminescence studies reveal that it displays distinct red-shifts of the emission whether the temperature is elevated or lowered from ambient temperature, suggestive of exceptional thermochromic phosphorescence characteristics.

17.
Angew Chem Int Ed Engl ; 62(48): e202311625, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37656120

RESUMO

The selectivity control of Pd nanoparticles (NPs) in the direct CO esterification with methyl nitrite toward dimethyl oxalate (DMO) or dimethyl carbonate (DMC) remains a grand challenge. Herein, Pd NPs are incorporated into isoreticular metal-organic frameworks (MOFs), namely UiO-66-X (X=-H, -NO2 , -NH2 ), affording Pd@UiO-66-X, which unexpectedly exhibit high selectivity (up to 99 %) to DMC and regulated activity in the direct CO esterification. In sharp contrast, the Pd NPs supported on the MOF, yielding Pd/UiO-66, displays high selectivity (89 %) to DMO as always reported with Pd NPs. Both experimental and DFT calculation results prove that the Pd location relative to UiO-66 gives rise to discriminated microenvironment of different amounts of interface between Zr-oxo clusters and Pd NPs in Pd@UiO-66 and Pd/UiO-66, resulting in their distinctly different selectivity. This is an unprecedented finding on the production of DMC by Pd NPs, which was previously achieved by Pd(II) only, in the direct CO esterification.

18.
Small ; 18(16): e2200046, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35266288

RESUMO

Passivation of the sulfur electrode by insulating lithium sulfide (Li2 S) restricts the reversibility and sulfur utilization of lithium-sulfur (Li-S) batteries. Although electrolytes with high donor number (DN) solvents induce tri-sulfur radical intermediate thus 3D nucleation of Li2 S with fast kinetics can be achieved, their catastrophic reactivities with Li metal hinder practical applications. Here, the use of high DN solvent as an additive instead of as co-solvent to solve their incompatibility between cathode and anode is proposed, by adopting N-methyl-2-pyrrolidone (NMP) as a proof-of-concept. Such a strategy is accomplished by the unique solvation structure of the NMP added electrolyte, where the preference of NMP-Li+ coordination squeezes out partial 1,2-dimethoxyethane (DME) molecules while enriching 1,3-dioxolane (DOL) molecules in the first solvation sheath of Li+ ions. It affords the robust SEI on Li metal from corrosion either by NMP or the dissolved polysulfides. Spectral analyses (Raman and UV-vis) also verify that the coordinated NMP additive preserves its S3 •- radicals stabilization ability as it does as a co-solvent, which effectively improves the sulfur conversion kinetics and reversibility. This approach enables competitive capacity retention and a stable cycling performance of 340 cycles, which is one of the longest lifespans known for the high DN solvent involved Li-S batteries.

19.
Small ; 18(20): e2200361, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35481610

RESUMO

Investigating the correlations of electron transport between multiple channels shows vital promises for the design of molecule-scale circuits with logic operations. To control the electron transport through multiple channels, the modulation of electronegativity shows an effective frontier orbit control method with high universality to explore the interactions between transport channels. Here, two series of compounds with a single nitrogenous conductive channel (Sg) and dual-channels (Db) are designed to explore the influence of electronegativity on electron tunneling transport. Single-molecule conductance measured via the scanning tunneling microscope break junction technique (STM-BJ) reveals that the conductance of Db series is significantly suppressed as the electronegativity of nitrogen becomes negative, while the suppression on Sg is less obvious. Theoretical calculations confirm that the effect of electronegativity extends to a dispersive range of molecular frameworks owing to the delocalized orbital distribution from the dual-channel structure, resulting in a more significant conductance suppression effect than that on the single-channel. This study provides the experimental and theoretical potentials of electronegativity gating for molecular circuits.


Assuntos
Nanotecnologia , Nitrogênio , Condutividade Elétrica , Transporte de Elétrons
20.
Chemistry ; 28(48): e202201299, 2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-35650011

RESUMO

Circular polarized luminescence (CPL)-active materials attract great attentions owing to their widely applications in 3D optical displays and encrypted transmission. Inspired by the strategies adopted in perovskite based CPL materials, herein, CPL-active hybrids (D)- and (L)-(tert-butyl prolinate)MnCl3 were successfully prepared by assembling chiral D/L tert-butyl prolinate with manganese (II) chloride. Single crystal structures show the as-formed hybrids possess one-dimensional (1D) structure containing linear chains of face-sharing MnCl6 octahedral surrounded by prolinate cations. The 1D Mn(II) hybrids display strong red emission peaked at 646 nm with PLQY of 67.1 % and 57.2 % for d-type and l-type, respectively, representing the highest PLQY for 1D MnII hybrids. Interestingly, the 1D Mn(II) hybrids exhibit prominent circular dichroism (CD) signals and remarkable CPL activity with the dissymmetry factor g of 6.1*10-3 and -6.3*10-3 from 550 to 800 nm for (D)- and (L)-(tert-butyl prolinate)MnCl3 , respectively, owing to the existence of chiral cations. It is worthy noted the obtained g represents the highest value for non-lead organic-inorganic hybrids.


Assuntos
Compostos Inorgânicos , Luminescência , Aminoácidos/química , Dicroísmo Circular , Manganês
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