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1.
J Cell Mol Med ; 28(3): e18097, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38164738

RESUMO

Current studies have indicated that insufficient trophoblast epithelial-mesenchymal transition (EMT), migration and invasion are crucial for spontaneous abortion (SA) occurrence and development. Exosomal miRNAs play significant roles in embryonic development and cellular communication. Hereon, we explored the roles of serum exosomes derived from SA patients on trophoblast EMT, migration and invasion. Exosomes were isolated from normal control (NC) patients with abortion for unplanned pregnancy and SA patients, then characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blotting. Exosomal miRNA profiles were identified by miRNA sequencing. The effects of serum exosomes on trophoblast migration and invasion were detected by scratch wound healing and transwell assays, and other potential mechanisms were revealed by quantitative real-time PCR (RT-PCR), western blotting and dual-luciferase reporter assay. Finally, animal experiments were used to explore the effects of exosomal miR-410-3p on embryo absorption in mice. The serum exosomes from SA patients inhibited trophoblast EMT and reduced their migration and invasion ability in vitro. The miRNA sequencing showed that miR-410-3p was upregulated in SA serum exosomes. The functional experiments showed that SA serum exosomes restrained trophoblast EMT, migration and invasion by releasing miR-410-3p. Mechanistically, SA serum exosomal miR-410-3p inhibited trophoblast cell EMT, migration and invasion by targeting TNF receptor-associated factor 6 (TRAF6) at the post-transcriptional level. Besides, SA serum exosomal miR-410-3p inhibited the p38 MAPK signalling pathway by targeting TRAF6 in trophoblasts. Moreover, milk exosomes loaded with miR-410-3p mimic reached the maternal-fetal interface and aggravated embryo absorption in female mice. Clinically, miR-410-3p and TRAF6 expression were abnormal and negatively correlated in the placental villi of SA patients. Our findings indicated that exosome-derived miR-410-3p plays an important role between SA serum and trophoblasts in intercellular communication, suggesting a novel mechanism by which serum exosomal miRNA regulates trophoblasts in SA patients.


Assuntos
Aborto Espontâneo , Exossomos , MicroRNAs , Humanos , Feminino , Gravidez , Camundongos , Animais , Exossomos/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Placenta/metabolismo , MicroRNAs/genética , Trofoblastos/metabolismo , Transição Epitelial-Mesenquimal/genética , Proliferação de Células , Movimento Celular/genética
2.
Phys Rev Lett ; 132(24): 243602, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38949332

RESUMO

Imposing topological operations encircling an exceptional point (EP) engenders unconventional one-way topological phonon transfer (TPT), strictly depending on the direction of EP-inclusive control loops and inherently limited to the small-mass regime of practical resonators. We here show how to beat these limitations and predict a mass-free unidirectional TPT by combining topological operations with the Fizeau light-dragging effect, which splits countercirculating optical modes. An efficient TPT happens when light enters from one chosen side of the fiber but not from the other, leading to a unique nonreciprocal TPT, independent of the direction of winding around the EP. Unlike previous proposals naturally sensitive to both mass and quality of quantum devices, our approach is almost immune to these factors. Remarkably, its threshold duration of adiabatic control loops for maintaining an optimal TPT can be easily shortened, yielding a top-speed-tunable perfect TPT that has no counterpart in previous demonstrations. The study paves a quite-general route to exploiting profoundly different chiral topological effects, independent of both EP-encircling direction and device mass.

3.
Exp Cell Res ; 424(1): 113473, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36634743

RESUMO

Long non-coding RNA (lncRNA) anomalies cause early ovarian failure. LncRNA nuclear enriched abundant transcript 1 (NEAT1) was down-regulated in premature ovarian failure (POF) mice and connected to the illness, however, the mechanism remained unclear. The levels of gene and protein were measured by using quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence. Follicle stimulating hormone (FSH), estradiol (E2), and luteinizing hormone (LH) levels were determined using enzyme-linked immunosorbent assay (ELISA). 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry were used to determine cell viability and apoptosis. The interaction of NEAT1, miR-654, and stanniocalcin-2 (STC2) was verified by dual-luciferase reporter assay or RNA binding protein immunoprecipitation (RIP) assays. The results showed NEAT1 and STC2 down-regulated, while miR-654 up-regulated in POF mice. Overexpression of NEAT1 reduced apoptosis and autophagy in cyclophosphamide (CTX)-treated ovarian granulosa cells (OGCs), and Bax, cleaved-caspase3, LC3B, LC3II/LC3I ratio were decreased and Bcl-2 and p62 were raised. NEAT1 suppressed miR-654 expression by directly targeting miR-654. The inhibition of NEAT1 overexpression on apoptosis and autophagy in OGCs was reversed by miR-654 mimics. STC2 was a target gene of miR-654, and miR-654 inhibitor reduced the apoptosis and autophagy by regulating the STC2/MAPK axis. To sum up, NEAT1 reduced miR-654 expression and modulated the STC2/MAPK pathway to decrease apoptosis and autophagy in POF, indicating a potential therapeutic target.


Assuntos
Apoptose , Autofagia , Células da Granulosa , MicroRNAs , RNA Longo não Codificante , Animais , Camundongos , Apoptose/genética , Autofagia/genética , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Transdução de Sinais , Células da Granulosa/metabolismo , Células da Granulosa/patologia
4.
Oral Dis ; 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37766627

RESUMO

OBJECTIVE: To analyse the histopathological features of eosinophilic sialodochitis by using terminal duct biopsy. METHODS: Sixty-five patients with suspected eosinophilic sialodochitis and four with chronic obstructive sialadenitis were prospectively enrolled. Clinical features, laboratory tests and sialograms were comparatively analysed. Terminal duct biopsy of the parotid or submandibular glands was performed concomitantly with endoscopy-assisted duct dilatation to determine the histopathological features of eosinophilic sialodochitis. RESULTS: Based on eosinophil quantification, the samples of suspected patients were scored as 'definite', 'highly suspected' and 'negative' in 26 (40%), 15 (23.1%) and 24 (36.9%) cases, respectively. Gland types and peripheral blood eosinophil counts were significantly different among these three groups. The proportions of itching glands, mucus plug exudations and elevated immunoglobulin E levels were higher in the 'definite' group than in the other two groups; however, the intergroup differences were insignificant. The primary pathological features of eosinophilic sialodochitis were abundant eosinophils and lymphocytes infiltrated around the duct, degranulation of eosinophils, extensive fibrosis and scattered mastocytes. Periductal eosinophils were not found in cases of chronic obstructive sialadenitis. CONCLUSION: Our findings suggest that terminal duct biopsy is safe and valuable for the pathological confirmation of eosinophilic sialodochitis, and can be used simultaneously with endoscopy-assisted duct dilatation.

5.
Oral Dis ; 2023 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-38073152

RESUMO

OBJECTIVES: To establish an inflammation grading system for radioactive iodine-induced sialadenitis (RAIS) based on spiral computed tomography (CT), ultrasonography and sialography. METHODS: In all, 120 RAIS patients (18 males and 102 females) were retrospectively included. Spiral CT, ultrasonography and sialography appearances were analysed and categorized as follows: grade I, approximately normal or mild sialadenitis; grade II, moderate sialadenitis; and grade III, severe sialadenitis. Adenitis severity was analysed relative to sex, age, RAI treatment sessions and cumulative doses. RESULTS: Spiral CT showed heterogeneous (78.9%) and atrophic changes (36.8%) in the parotid glands (PGs) and duct ectasia (24.8%) in the submandibular glands (SMGs). Ultrasonography showed heterogeneous echogenicity (54.3%) and diminished gland size (30.2%) in PGs and duct ectasia in SMGs (34.7%). Sialography showed duct obliteration in 25.3% PGs and 3.2% SMGs. Statistical analysis showed good consistency among the three imaging grading results. The incidence and severity of PG lesions were significantly higher than that of SMGs (p < 0.001). As for PGs, adenitis severity was associated with both treatment sessions and cumulative doses; but in SMGs, disease severity was only related to treatment sessions. CONCLUSIONS: A grading system for severity of RAIS was established based on spiral CT, ultrasonography and sialography appearances.

6.
J Am Chem Soc ; 144(47): 21448-21456, 2022 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-36395247

RESUMO

Design of ligands in transition-metal catalyzed reactions is challenging, especially in asymmetric transformations. With each step in the catalytic cycle promoted by its privileged ligand and different steps well-connected by dynamic ligand exchange, synergistic combination of multiple ligands could potentially enhance the catalytic efficiency and selectivity. Now, this concept has been applied to the NiH-catalyzed asymmetric remote hydroacylation of olefins and migratory acylation of alkyl halides with excellent regio- and enantioselectivity, utilizing two simple ligands, one for chain-walking and the other for asymmetric acylation. Starting from abundant alkenes/alkyl halides and carboxylic acids, a wide range of enantioenriched chiral α-aryl ketones can be efficiently accessed under mild conditions.


Assuntos
Alcenos , Compostos Inorgânicos , Ligantes , Catálise , Acilação
7.
Phys Rev Lett ; 129(6): 063602, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-36018654

RESUMO

Entanglement of light and multiple vibrations is a key resource for multichannel quantum information processing and memory. However, entanglement generation is generally suppressed, or even fully destroyed, by the dark-mode (DM) effect induced by the coupling of multiple degenerate or near-degenerate vibrational modes to a common optical mode. Here we propose how to generate optomechanical entanglement via DM breaking induced by synthetic magnetism. We find that at nonzero temperature, light and vibrations are separable in the DM-unbreaking regime but entangled in the DM-breaking regime. Remarkably, the threshold thermal phonon number for preserving entanglement in our simulations has been observed to be up to 3 orders of magnitude stronger than that in the DM-unbreaking regime. The application of the DM-breaking mechanism to optomechanical networks can make noise-tolerant entanglement networks feasible. These results are quite general and can initiate advances in quantum resources with immunity against both dark modes and thermal noise.

8.
Zhongguo Zhong Yao Za Zhi ; 47(11): 2899-2908, 2022 Jun.
Artigo em Zh | MEDLINE | ID: mdl-35718510

RESUMO

Chinese medicinal materials are the precious resources of China and favored by patients at home and abroad because of their natural sources and curative effects. Pesticides are often used to prevent and control diseases and insect pests and regulate the growth of Chinese medicinal plants, so as to improve the yield and quality of Chinese medicinal materials. Most of the pesticides can play a role in pest control through systemic action, stomach toxicity, contact, fumigation and other ways, especially the systemic pesticides can kill hidden pests by entering the Chinese medicinal plants. Despite the good pest control effect, it is difficult to remove the systemic pesticides by simple cleaning, which poses a great risk to the safety of Chinese medicinal materials. At the same time, excessive or non-standard use of pesticides leads to serious pesticide residues in Chinese medicinal materials, which affects not only the quality and efficacy of the materials and harm human health but also the international development of Chinese medicinal materials industry. Pesticide residues have become a bottleneck affecting the industry development and hindering the export of Chinese medicinal materials. Therefore, it is of great significance to study how to quickly, sensitively, and accurately detect and remove pesticide residues in Chinese medicinal materials. We reviewed the common pesticide residues in Chinese medicinal materials in recent years in terms of characteristics, harm, and detection and removal techniques, and discussed the future development of the detection and removal deve-lopment. With this review, we aimed to provide a reference for the quality control of Chinese medicinal materials and promote the healthy development of Chinese medicine industry.


Assuntos
Resíduos de Praguicidas , Praguicidas , Plantas Medicinais , Fumigação , Humanos , Medicina Tradicional Chinesa , Resíduos de Praguicidas/análise , Praguicidas/análise , Praguicidas/toxicidade
9.
Bioorg Med Chem Lett ; 40: 127968, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33753264

RESUMO

A series of 5-phenyloxazole-2-carboxylic acid derivatives were synthesized, and their structure-activity relationships (SARs) were studied. N,5-diphenyloxazole-2-carboxamides 6, 7, and 9, which mimicked ABT751, showed improved cytotoxicity compared with ABT751. Compound 9 exhibited the highest antiproliferative activities against Hela A549, and HepG2 cancer cell lines, with IC50 values of 0.78, 1.08, and 1.27 µM, respectively. Furthermore, compound 9 showed selectivity for human cancer cells over normal cells, and this selectivity was greater than those of ABT751 and colchicine. Preliminary mechanism studies suggested that compound 9 inhibited tubulin polymerization and led to cell cycle arrest at G2/M phase. Molecular docking studies indicated that compound 9 bound to the colchicine binding site of tubulin. Our findings provided insights into useful SARs for further structural modification of inhibitors of tubulin polymerization.


Assuntos
Antineoplásicos/farmacologia , Oxazóis/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Oxazóis/síntese química , Oxazóis/metabolismo , Polimerização/efeitos dos fármacos , Ligação Proteica , Relação Estrutura-Atividade , Tubulina (Proteína)/química , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/metabolismo
10.
Surg Radiol Anat ; 43(6): 1009-1018, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34023911

RESUMO

PURPOSE: The aim of this study was to analyze the morphologic features of alveolus in relatively healthy maxillary and mandibular incisors using cone-beam-computed tomography (CBCT). METHODS: CBCT images of 318 patients were retrospectively acquired. Alveolar bone in incisive area was divided into: type 1 (thick), type 2 (relatively thick with mono-plate concavity), type 3 (thin with double-plate concavities), and type 4 (vulnerably thin). Alveolus prevalence and widths were analyzed statistically relative to age, gender, and molar relationship. RESULTS: Prevalence of type 1 alveolus was 78.9% in maxillary central incisors, 15.1% in maxillary lateral incisors, 24.1% in mandibular central incisors, and 5.0% in mandibular lateral incisors. Type 2 alveolus was commonly observed in the maxillary lateral incisors (82.2%), mandibular central incisors (66.2%), and mandibular lateral incisors (87.9%). Prevalence of type 3 and 4 alveoli ranged from 0.0 to 9.4%. As for maxillary central incisors, type 1 was the widest both at the alveolar crest (7.77 ± 0.58 mm) and apical area (9.05 ± 1.86 mm), while type 3 had the lowest width at the apical region (4.08 ± 0.51 mm). Among maxillary central incisors, prevalence of type 1 tended to decrease with age. At all maxillary and mandibular incisor sites, alveolus widths were significantly thicker in males than in females. At maxillary lateral incisor and mandibular incisor sites, prevalence of alveolus type was significantly different among three molar relationships. CONCLUSION: A 4-type classification system was suggested for alveolus morphology in incisive region. Identification of alveolus type might aid in the corresponding treatment.


Assuntos
Processo Alveolar/anatomia & histologia , Incisivo/anatomia & histologia , Mandíbula/anatomia & histologia , Maxila/anatomia & histologia , Adolescente , Adulto , Fatores Etários , Processo Alveolar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Incisivo/diagnóstico por imagem , Masculino , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem , Pessoa de Meia-Idade , Radiografia Dentária , Estudos Retrospectivos , Fatores Sexuais , Adulto Jovem
11.
Angew Chem Int Ed Engl ; 60(39): 21434-21440, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34319649

RESUMO

Through the incorporation of various halogen-substituted chiral organic cations, the effects of chiral molecules on the chiroptical properties of hybrid organic-inorganic perovskites (HOIPs) are investigated. Among them, the HOIP having a Cl-substituted chiral cation exhibits the highest circular dichroism (CD) and circular polarized luminescence (CPL) intensities, indicating the existence of the largest rotatory strength, whereas the F-substituted HIOP shows the weakest intensities. The observed modulation can be correlated to the varied magnetic transition dipole of HOIPs, which is sensitive to the d-spacing between inorganic layers and the halogen-halogen interaction between organic cations and the inorganic sheets. These counteracting effects meet the optimal CD and CPL intensity with chlorine substitution, rendering the rotatory strength of HOIPs arranged in the order of (ClMBA)2 PbI4 >(BrMBA)2 PbI4 >(IMBA)2 PbI4 >(MBA)2 PbI4 >(FMBA)2 PbI4 .

12.
Angew Chem Int Ed Engl ; 60(14): 7866-7872, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33403749

RESUMO

2D perovskites with chemical formula A'2 An-1 Bn X3n+1 have recently attracted considerable attention due to their tunable optical and electronic properties, which can be attained by varying the chemical composition. While high color-purity emitting perovskite nanomaterials have been accomplished through changing the halide composition, the preparation of single-phase, specific n-layer 2D perovskite nanomaterials is still pending because of the fast nucleation process of nanoparticles. We demonstrate a facile, rational and efficacious approach to synthesizing single-phase 2D perovskite nanoplates with a designated n number for both lead- and tin-based perovskites through kinetic control. Casting carboxylic acid additives in the reaction medium promotes selective formation of the kinetic product-multilayer 2D perovskite-in preference to the single-layer thermodynamic product. For the n-specific layered 2D perovskites, decreasing the number of octahedral layers per inorganic sheet leads to an increase of photoluminescence energy, radiative decay rate, and a significant boost in photostability.

13.
J Am Chem Soc ; 142(16): 7469-7479, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32223139

RESUMO

Dinuclear Pt(III) complexes were commonly reported to have short-lived lowest-lying triplet states, resulting in extremely weak or no photoluminescence. To overcome this obstacle, a new series of dinuclear Pt(III) complexes, named Pt2a-Pt2c, were strategically designed and synthesized using donor (D)-acceptor (A)-type oxadiazole-thiol chelates as bridging ligands. These dinuclear Pt(III) complexes possess a d7-d7 electronic configuration and exhibit intense phosphorescence under ambient conditions. Among them, Pt2a exhibits orange phosphorescence maximized at 618 nm in degassed dichloromethane solution (Φp ≈ 8.2%, τp ≈ 0.10 µs) and near-infrared (NIR) emission at 749 nm (Φp ≈ 10.1% τp ≈ 0.66 µs) in the crystalline powder and at 704 nm (Φp ≈ 33.1%, τp ≈ 0.34 µs) in the spin-coated neat film. An emission blue-shifted by more than 3343 cm-1 is observed under mechanically ground crystalline Pt2a, affirming intermolecular interactions in the solid states. Time-dependent density functional theory (TD-DFT) discloses the lowest-lying electronic transition of Pt2a-Pt2c complexes to be a bridging ligand-metal-metal charge transfer (LMMCT) transition. The long-lived triplet states of these dinuclear platinum(III) complexes may find potential use in lighting. Employing Pt2a as an emitter, high-performance organic light-emitting diodes (OLEDs) were fabricated with NIR emission at 716 nm (η = 5.1%), red emission at 614 nm (η = 8.7%), and white-light emission (η = 11.6%) in nondoped, doped (in mCP), and hybrid (in CzACSF) devices, respectively.

14.
Opt Express ; 28(11): 16175-16190, 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32549445

RESUMO

We study the photon blockade effect in a coupled cavity system, which is formed by a linear cavity coupled to a Kerr-type nonlinear cavity via a photon-hopping interaction. We explain the physical phenomenon from the viewpoint of the conventional and unconventional photon blockade effects. The corresponding physical mechanisms of the two kinds of photon blockade effects are based on the anharmonicity in the eigenenergy spectrum and the destructive quantum interference between two different transition paths, respectively. In particular, we find that the photon blockade via destructive quantum interference also exists in the conventional photon blockade regime and that the unconventional photon blockade occurs in both the weak- and strong-Kerr nonlinearity cases. The photon blockade effect can be observed by calculating the second-order correlation function of the cavity field. This model is general and hence it can be implemented in various experimental setups such as coupled optical-cavity systems, coupled photon-magnon systems, and coupled superconducting-resonator systems. We present some discussions on the experimental feasibility.

15.
Chemistry ; 26(31): 7124-7130, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32149442

RESUMO

The weak fluorescence (quantum yield <1 % in cyclohexane) of phenothiazine (PTZ) impedes its further application. In addition, the nitro group (NO2 ) is a well-known fluorescence quencher. Interestingly, we obtained a highly fluorescent chromophore by combining these two moieties, forming 3-nitrophenothiazine (PTZ-NO2 ). For comparison, a series of PTZ derivatives bearing electron-withdrawing groups (EWGs; CN and CHO) or electron-donating groups (EDGs; OMe) at the 3-position have been designed and synthesized. The phenothiazines bearing EWGs exhibited enhanced emission compared with the parent PTZ or EDG derivatives. Computational approaches unveiled that for PTZ and PTZ-OMe, the transitions are from HOMOs dominated by π orbitals to LUMOs of mixed sulfur nonbonding-π* orbitals, and hence are partially forbidden. In contrast, the EWGs lower the energy level of the lone-pair electrons on the sulfur atom, thereby suppressing the mixing of the nonbonding orbital with the π* orbital in the LUMO, such that the allowed ππ* transition becomes dominant. This work thus demonstrates a judicious chemical design to fine-tune the transition character in PTZ analogues, with PTZ-NO2 attaining 100 % emission quantum yields in nonpolar solvent.

16.
J Am Chem Soc ; 141(13): 5535-5543, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30835458

RESUMO

A series of platinum(II) metallacycles were prepared via the coordination-driven self-assembly of a phenazine-cored dipyridyl donor with a 90° Pt(II) acceptor and various dicarboxylate donors in a 1:1:2 ratio. While the metallacycles display similar absorption profiles, they exhibit a trend of blue-shifted fluorescence emission with the decrease in the bite angles between the carboxylate building blocks. Comprehensive spectroscopic and dynamic studies as well as a computational approach were conducted, revealing that the difference in the degree of constraint imposed on the excited-state planarization of the phenazine core within these metallacycles results in their distinct photophysical behaviors. As such, a small initial difference in the dicarboxylate building blocks is amplified into distinct photophysical properties of the metallacycles, which is reminiscent of the efficient functional tuning observed in natural systems. In addition to the pre-assembly approach, the photophysical properties of a metallacycle can also be modulated using a post-assembly modification to the dicarboxylate building block, suggesting another strategy for functional tuning. This research illustrated the potential of coordination-driven self-assembly for the preparation of materials with precisely tailored functionalities at the molecular level.


Assuntos
Fluorescência , Compostos Organometálicos/síntese química , Fenazinas/química , Platina/química , Conformação Molecular , Compostos Organometálicos/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
17.
J Am Chem Soc ; 141(25): 9885-9894, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31244136

RESUMO

We report O-H----S hydrogen-bond (H-bond) formation and its excited-state intramolecular H-bond on/off reaction unveiled by room-temperature phosphorescence (RTP). In this seminal work, this phenomenon is demonstrated with 7-hydroxy-2,2-dimethyl-2,3-dihydro-1 H-indene-1-thione (DM-7HIT), which possesses a strong polar (hydroxy)-dispersive (thione) type H-bond. Upon excitation, DM-7HIT exhibits anomalous dual RTP with maxima at 550 and 685 nm. This study found that the lowest lying excited state (S1) of DM-7HIT is a sulfur nonbonding (n) to π* transition, which undergoes O-H bond flipping from S1(nπ*) to the non-H-bonded S'1(nπ*) state, followed by intersystem crossing and internal conversion to populate the T'1(nπ*) state. Fast H-bond on/off switching then takes place between T'1(nπ*) and T1(nπ*), forming a pre-equilibrium that affords both the T'1(nπ*, 685 nm) and T1(nπ*, 550 nm) RTP. The generality of the sulfur H-bond on/off switching mechanism, dubbed a molecule wiper, was rigorously evaluated with a variety of other H-bonded thiones, and these results open a new chapter in the chemistry of hydrogen bonds.

18.
J Am Chem Soc ; 141(26): 10324-10330, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31244186

RESUMO

Tin perovskite nanomaterial is one of the promising candidates to replace organic lead halide perovskites in lighting applications. Unfortunately, the performance of tin-based systems is markedly inferior to those featuring toxic Pb salts. In an effort to improve the emission quantum efficiency of nanoscale 2D layered tin iodide perovskites through fine-tuning the electronic property of organic ammonium salts, we came to unveil the relationship between dielectric confinement and the photoluminescent properties of tin iodide perovskite nanodisks. Our results show that increasing the dielectric contrast for organic versus inorganic layers leads to a bathochromic shift in emission peak wavelength, a decrease of exciton recombination time, and importantly a significant boost in the emission efficiency. Under optimized conditions, a leap in emission quantum yield to a record high 21% was accomplished for the nanoscale thienylethylammonium tin iodide perovskite (TEA2SnI4). The as-prepared TEA2SnI4 also possessed superior photostability, showing no sign of degradation under continuous irradiation (10 mW/cm2) over a period of 120 h.

19.
Chemistry ; 25(72): 16755-16764, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31663166

RESUMO

With the aim of generalizing the structure-properties relationship of bending heterocyclic molecules that undergo prominent photoinduced structural planarization (PISP), a series of new dihydrodibenzo[ac]phenazine derivatives in which one nitrogen atom is replaced by oxygen (PNO), sulfur (PNS), selenium (PNSe), or dimethylmethanediyl (PNC) was strategically designed and synthesized. Compounds PNO, PNS, and PNSe have significantly nonplanar geometries in the ground state, which undergo PISP to give a planarlike conformer and hence a large emission Stokes shift. A combination of femtosecond early relaxation dynamics and computational approaches established an R*→I* (intermediate)→P* sequential kinetic pattern for PNS and PNSe, whereas PNO undergoes R*→P* one-step kinetics. The polarization ability of the substituted heteroatoms, which is in the order O

20.
J Oral Maxillofac Surg ; 77(2): 328.e1-328.e9, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30395822

RESUMO

PURPOSE: To quantify gland function before and after endoscopy-assisted lithectomy for patients with parotid stones and to analyze correlations among different evaluation modalities. MATERIALS AND METHODS: This study investigated 58 patients (27 men and 31 women) with a stone larger than 5 mm or multiple parotid stones who underwent successful endoscopy-assisted surgery at the authors' center from August 2007 through September 2017. Meticulous postoperative manipulations were administered routinely for 3 to 6 months to promote functional recovery of the affected gland. Gland function was evaluated preoperatively and 6 to 36 months (mean, 12 months) postoperatively by sialography, scintigraphy, and sialometry. Statistical analyses were conducted to quantify gland function recovery and to distinguish correlations among the 3 objective tests. RESULTS: Preoperative sialograms exhibited ductal ectasia at the stone site with ductal stenosis anterior to the stone (n = 53) or duct interruption at the stone site (n = 5). Postoperative sialograms of 45 patients without stones were categorized as approximately normal (type I; n = 17); showing ectasia or stenosis of the main duct without persistent contrast on the functional film (type II; n = 16); showing ectasia or stenosis of the main duct with mild contrast retention (type III; n = 6); or showing poor ductal shape with evident contrast retention (type IV; n = 6). Scintigraphy of 23 preoperative and 12 postoperative patients and sialometry of 24 preoperative and 12 postoperative patients indicated severe preoperative impairment and postoperative improvement of gland function. Postoperatively, although no relevant differences in saliva flow rate were found between the 2 sides, scintigraphy showed lower function of the affected gland compared with the control side. Statistical data showed positive correlations among the 3 methods. Sialography intuitively reflected the ductal shape, whereas sialometry and scintigraphy were more sensitive for evaluating gland function. CONCLUSION: For patients with parotid stones, minimally invasive endoscopic surgery and meticulous postoperative manipulations help preserve the glands and facilitate recovery of gland function. The 3 evaluating modalities have certain positive correlations.


Assuntos
Doenças Parotídeas , Glândula Parótida , Cálculos dos Ductos Salivares , Cálculos das Glândulas Salivares , Endoscopia , Feminino , Humanos , Masculino , Sialografia
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