Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
1.
Inorg Chem ; 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39088793

RESUMO

We report square planar mononuclear Pt(II)-complexes of terpyridines in the form of [PtCl(L1/L2)]PF6 as phosphorescent emitters (where L1 = 4-(3-pyridine)2,2':6',2''-terpyridine and L2 = 4'-(3-pyridinyl)-4,4''-di(tert-butyl)-2,2':6'2''-terpyridine). Complex 2 showed emission at 534 nm in the DCM solution with photoluminescence quantum efficiency (ΦPL) = 14%, while in the mCBP host (5-wt % doped), the emission shifted to 584 nm with ΦPL = 37.8% and a phosphorescence lifetime (τphos) of 37.8 µs. Complex 2 in mCBP was used to fabricate a solution-processed phosphorescent organic light-emitting diode (PhOLED) which showed maximum external quantum efficiency (EQEmax) = 7.4% with yellow emission at λEL = 570 nm and exhibited a low efficiency roll-off with an EQE drop to 7.0% at 1000 cd/m2.

2.
Gen Dent ; 72(3): 34-40, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38640004

RESUMO

The majority of problematic conditions resulting from dental implant treatment are inflammatory in character, but certain isolated occurrences of primary oral squamous cell carcinoma (OSCC) have been discovered in the area of implants. The goal of this study was to examine whether there is a link between dental implants and the development of OSCC in patients who have a history of a potentially malignant lesion (PML) or malignancy. Using the keywords "carcinoma" AND "dental implants," a search was conducted in the MEDLINE (PubMed), National Center for Biotechnology Information, and Google Scholar databases for case reports and case series in which OSCC was discovered as a primary cancer in the region of dental implants. An initial search identified 260 articles, 247 of which were excluded based on study inclusion or exclusion criteria, leaving 13 articles chosen for inclusion and a total of 30 patients who developed primary oral cancer surrounding osseointegrated titanium-based dental implants. In the studies included in the present review, 22 (73%) of 30 patients with peri-implant cancer had a history of PML or carcinoma. There is no statistical evidence of a direct association between dental implants and OSCC in patients with a history of a PML or malignant lesion. There have been some case reports of OSCC in the region of dental implants in patients with a history of a PML or malignant lesion, but further studies are needed to prove a definitive relationship.


Assuntos
Carcinoma de Células Escamosas , Implantes Dentários , Neoplasias Bucais , Humanos , Implantes Dentários/efeitos adversos , Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/patologia , Neoplasias Bucais/etiologia
3.
Chem Commun (Camb) ; 60(33): 4459-4462, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38563754

RESUMO

Modification of an unsymmetric B,O,N-doped aromatic core with peripheral mesogenic units triggers self-assembly into a columnar hexagonal mesophase, which is stable between 22 and 144 °C. The columnar assembly is preserved in a glassy state below 22 °C. The B,O,N-doped mesogen displays narrowband sky-blue multiresonance thermally activated delayed fluorescence (MR-TADF) under diluted conditions and bright excimer emission in condensed phase. Our combined experimental and theoretical approach provides insight into the development of strongly aggregating liquid crystalline MR-TADF emitters.

4.
J Mol Model ; 30(3): 91, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38427116

RESUMO

CONTEXT: La2Mo2O9 is a potential electrolyte material for SOFC due to its higher oxygen conduction at high temperatures. However, La2Mo2O9 suffers from detrimental phase transition at high temperature from monoclinic α to cubic ß phase. This phase transition can be prevented by lowering the temperature. However, lowering the temperature reduces the ionic conductivity. Substitution of transition metal on Mo site is the best strategy for the suppression of phase transition. In the present work, the effect of substituting element on different sites has been investigated. From the result, it is observed that the band gap increases with concentration of Er. METHOD: For the assessment of mechanism behind the improved performance, the atomic insight is crucial. For that, we have employed ab initio DFT calculation. We have used PBE and grimme d3 dispersion correction for the accuracy of evaluated band gap and electrochemical stability. All DFT calculations have been performed using Quantum ESPRESSO pwscf code's and for the assessment of thermodynamical stability of La2Mo2O9 and the doped structures, an alternative descriptor, the global instability index (GII), which is based on the bond valance sum approach implemented in SoftBV was used. All the visualizations were done by XCrySDen and VESTA open source software.

5.
J Indian Prosthodont Soc ; 24(1): 76-81, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38263561

RESUMO

AIM: Occlusal splint treatment is commonly used to treat a variety of temporomandibular disorders (TMDs), with efficacy ranging between 70% and 90%. Centric splints are effective in relieving muscular soreness in individuals with TMD. Electromyography (EMG) quantifies muscle activity and can be used as an accessory diagnostic tool to evaluate the efficiency of the splint on the masticatory complex. Electromyography is used for assessing patients with TMD and observing muscle electromyography. TMD patients have altered electromyographic (EMG) masticatory muscle activity because of its change in electrical activity index or because of the compensatory mechanism for the disorder. Therefore, this study serves to evaluate the efficacy of the centric stabilization splint on TMD using EMG. SETTINGS AND DESIGN: This cross-sectional study enrolled Ten TMD Patients with TMD, who underwent treatment with centric stabilization splint. MATERIALS AND METHODS: The study involved ten young adults with TMD aged 18-45 years who were recruited without regard to sex, religion, caste, or socioeconomic background. The participants were randomized to receive a flat-contact upper stabilization splint and pregelled EMG electrodes to assess the immediate impact of centric splints on TMDs. After 3 months of follow-up, muscle activity and muscle symmetrical activity were measured to assess improvement in the symptoms of TMD. STATISTICAL ANALYSIS USED: The Shapiro-Wilk test was used to assess the normality of the variables' distribution using SPSS 26.0. Symmetrical activity and treatment response were investigated using the Wilcoxon signed-rank test. RESULTS: It showed an improvement in the temporalis, masseter, and sternocleidomastoid muscles' resting EMG activity. A statistically significant improvement was seen in the EMG activity of the bilateral temporalis, right masseter, right sternocleidomastoid, and left digastric muscles while clenching. The masseter, sternocleidomastoid, and digastric muscles all displayed significantly enhanced symmetrical activity (P < 0.05). CONCLUSIONS: This research concludes that a centric stabilizing splint assists in relieving TMD symptoms. There was enhanced masticatory muscle activity both at rest and during function. Furthermore, there was an improvement in symmetrical activity of the masticatory muscles, which improved balance and enhanced the effective functioning of the masticatory complex.


Assuntos
Transtornos da Articulação Temporomandibular , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Estudos Transversais , Músculos da Mastigação , Músculos do Pescoço , Contenções
6.
Chem Sci ; 15(2): 545-554, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38179537

RESUMO

Organic small molecules exhibiting both thermally activated delayed fluorescence (TADF) and wide-ranging piezochromism (Δλ > 150 nm) in the near-infrared region have rarely been reported in the literature. We present three emitters MeTPA-BQ, tBuTPA-BQ and TPPA-BQ based on a hybrid acceptor, benzo[g]quinoxaline-5,10-dione, that emit via TADF, having photoluminescence quantum yields, ΦPL, of 39-42% at photoluminescence (PL) maxima, λPL, of 625-670 nm in 2 wt% doped films in 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP). Despite their similar chemical structures, the PL properties in the crystalline states of MeTPA-BQ (λem = 735 nm, ΦPL = 2%) and tBuTPA-BQ (λem = 657 nm, ΦPL = 11%) are significantly different. Further, compounds tBuTPA-BQ and TPPA-BQ showed a significant PL shift of ∼98 and ∼165 nm upon grinding of the crystalline samples, respectively. Deep-red organic light-emitting diodes with MeTPA-BQ and tBuTPA-BQ were also fabricated, which showed maximum external quantum efficiencies, EQEmax, of 10.1% (λEL = 650 nm) and 8.5% (λEL = 670 nm), respectively.

8.
Angew Chem Int Ed Engl ; 62(43): e202309718, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37656606

RESUMO

Corannulene-derived materials have been extensively explored in energy storage and solar cells, however, are rarely documented as emitters in light-emitting sensors and organic light-emitting diodes (OLEDs), due to low exciton utilization. Here, we report a family of multi-donor and acceptor (multi-D-A) motifs, TCzPhCor, TDMACPhCor, and TPXZPhCor, using corannulene as the acceptor and carbazole (Cz), 9,10-dihydro-9,10-dimethylacridine (DMAC), and phenoxazine (PXZ) as the donor, respectively. By decorating corannulene with different donors, multiple phosphorescence is realized. Theoretical and photophysical investigations reveal that TCzPhCor shows room-temperature phosphorescence (RTP) from the lowest-lying T1 ; however, for TDMACPhCor, dual RTP originating from a higher-lying T1 (T1 H ) and a lower-lying T1 (T1 L ) can be observed, while for TPXZPhCor, T1 H -dominated RTP occurs resulting from a stabilized high-energy T1 geometry. Benefiting from the high-temperature sensitivity of TPXZPhCor, high color-resolution temperature sensing is achieved. Besides, due to degenerate S1 and T1 H states of TPXZPhCor, the first corannulene-based solution-processed afterglow OLEDs is investigated. The afterglow OLED with TPXZPhCor shows a maximum external quantum efficiency (EQEmax ) and a luminance (Lmax ) of 3.3 % and 5167 cd m-2 , respectively, which is one of the most efficient afterglow RTP OLEDs reported to date.

9.
Org Lett ; 25(31): 5880-5884, 2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37498083

RESUMO

Bromo-functionalized B1-polycyclic aromatic hydrocarbons (PAHs) with LUMOs of less than -3.0 eV were synthesized and used in cross-couplings to form donor-acceptor materials. These materials spanned a range of S1 energies, with a number showing thermally activated delayed fluorescence and significant emission in the near-infrared region of the spectrum. These B1-PAHs represent a useful family of acceptors that can be readily synthesized and functionalized.

10.
J Am Chem Soc ; 145(3): 1945-1954, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36638828

RESUMO

The design and regulation of multiple room-temperature phosphorescence (RTP) processes are formidably challenging due to the restrictions imposed by Kasha's rule. Here, we report a general design principle for materials that show multiple RTP processes, which is informed by our study of four compounds where there is modulation of the linker hybridization between donor (D) and acceptor (A) groups. Theoretical modeling and photophysical experiments demonstrate that multiple RTP processes can be achieved in sp3 C-linked D-A compounds due to the arrest of intramolecular electronic communication between two triplet states (T1H and T1L) localized on the donor and acceptor or between two triplet states, one localized on the donor and one delocalized across aggregated acceptors. However, for the sp2 C-linked D-A counterparts, RTP from one locally excited T1 state is observed because of enhanced excitonic coupling between the two triplet states of molecular subunits. Single-crystal and reduced density gradient analyses reveal the influence of molecular packing on the coincident phosphorescence processes and the origin of the observed aggregate phosphorescence. These findings provide insights into higher-lying triplet excited-state dynamics and into a fundamental design principle for designing compounds that show multiple RTP.

11.
J Oral Biol Craniofac Res ; 13(2): 146-149, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36605774

RESUMO

Cranial defects are repaired for esthetics, functional, morphological and psychological benefit of the affected patients. Purpose of a cranioplast is to prevent trauma to brain tissue, improve the cranial contour, symmetry and esthetics along with pain reduction. This technique describes the innovative use of a multicamera 3D face scanning software for obtaining a 3D face model of a road traffic accident patient for cranioplast fabrication. Advantage of this technique is that it is quick and easy and allows complete face scan under 10 s.

12.
J Indian Prosthodont Soc ; 22(1): 65-73, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36510949

RESUMO

Aim: The purpose of this study is to comparatively evaluate the Vitamin D supplementation and stabilization splint therapy in patients exhibiting temporomandibular disorders (TMD). Settings and Design: The study design was double-blinded, parallel-group, randomized and placebo-controlled trial conducted in patients with low Vitamin D and TMDs, which were allocated to two groups, Study group S + D (Stabilization splint with Vitamin D supplementation) and Control Group S (Stabilization Splint with placebo drug). Subjects and Methods: Thirty-six participants of 18-45 years of age gap with Vitamin D deficiency and TMD were included in the study. Preoperative values of Vitamin D levels in ng/ml, comfort mouth opening (CMO) in mm, maximum mouth opening (MMO) in mm, temporomandibular joint (TMJ) tenderness (grading 0-3), Visual analog scale score (VAS Score 0-10 cm), and total energy (TE) integral values of both left and right TMJ's in Hertz (Hz) were recorded using joint vibration analysis All the values of CMO, MMO, TMJ Tenderness and VAS were recorded at each follow-up at 1st week, 1st month, 2nd month, and 3rd month, respectively. Postoperative Vitamin D levels and TE of both TMJs were recorded at end of 3 months. Statistical Analysis Used: For intergroup comparison, Mann-Whitney U-test and Pearson Chi-square tests were done. For Intragroup comparison, Wilcoxon signed rank test was used for comparison. Results: In Intergroup comparison, a significant difference was seen in CMO, VAS score and MMO (P < 0.05) but not among mean values of TE of right and left TMJ, and Vitamin D levels (P < 0.05). In both groups, there were significant statistical variations in CMO, VAS score, MMO, and TE integral before and after treatment in the right and left TMJs (P < 0.05). Conclusions: The study concludes centric stabilization splint helps in improving symptoms of TMD patients and Vitamin D supplementation provided faster relief in those cases.


Assuntos
Placas Oclusais , Transtornos da Articulação Temporomandibular , Humanos , Vitamina D/uso terapêutico , Resultado do Tratamento , Transtornos da Articulação Temporomandibular/tratamento farmacológico , Contenções , Artralgia
13.
J Mol Model ; 28(11): 363, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36242654

RESUMO

In our work, the ab-initio methods based on density functional theory (DFT) formalism are used to investigate the effect of nitrogen-rich ionic liquid (EMIMDCA; 1-ethyl-3-methylimidazolium dicyanamide) on the electronic structure of SPE (solid polymer electrolyte) (PEO-LiTFSI) electrolyte with B3LYP method and LANL2DZ basis set. The differences in energy levels of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), i.e., energy gap ([Formula: see text]) of the PEO, [EMIMDCA], SPE, and ionogel (IG), are found 5.74, 6.59, 3.25, and 2.80 eV, respectively. In SPE, the reduced band gap ([Formula: see text]) is due to the transportation of cation of LiTFSI (Li+ ion). Finally, the reduced band gap of IG confirms that IL enhances the transportation of cation of LiTFSI (Li+ ion) through the oxygen atom of PEO. The global and local chemical descriptors and electrochemical stability windows (ESWs) are calculated using the HOMO-LUMO energy levels. Partial charge analysis is studied by Mulliken population analysis and molecular electrostatic potential surface.

14.
Angew Chem Int Ed Engl ; 61(33): e202206681, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35684990

RESUMO

Room-temperature phosphorescence (RTP) originating from higher-lying triplet excitons remains a rather rarely documented occurrence for purely organic molecular systems. Here, we report two naphthalene-based RTP luminophores whose phosphorescence emission is enabled by radiative decay of high-lying triplet excitons. In contrast, upon cooling the dominant phosphorescence originates from the lowest-lying triplet excited state, which is manifested by a red-shifted emission. Photophysical and theoretical studies reveal that the unusual RTP results from thermally activated excitonic coupling between different conformations of the compounds. Aggregation-regulated excitonic coupling is observed when increasing the doping concentration of the emitters in poly(methylmethacrylate) (PMMA). Further, the RTP quantum efficiency improves more than 80-fold in 1,3-bis(N-carbazolyl)benzene (mCP) compared to that in PMMA. This design principle offers important insight into triplet excited state dynamics and has been exploited in afterglow-indicating temperature sensing.

15.
Ann Maxillofac Surg ; 12(2): 240-243, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36874772

RESUMO

Rationale: Traumatic brain injury is the most common cause of cranial defects. Cranioplasty is the surgical intervention performed to repair cranial defects. The purpose of a cranioplast is to protect the underlying brain tissues, reduce pain, and improve calvarial contour and symmetry. Patient Concerns: This case report describes the management of an ambulatory aided patient who met with a road traffic accident and had undergone decompressive craniectomy. Diagnosis: Noncontrast computed tomography confirmed the frontal cranial defect and was planned for decompressive craniectomy. Treatment Plan: An innovative multi-camera three-dimensional (3D) face-scanning software (Bellus 3D) was used for facial scanning to obtain a 3D face model and fabrication of 3D model using rich presence technology. Outcomes: The wax pattern was then fabricated on a 3D-prototyped model and a customised polymethylmethacrylate cranioplast was fabricated. Take-Away Lessons: his method with the added advantage of rapid prototyping technology resulted in prosthesis with good aesthetics and better fit.

16.
Photochem Photobiol ; 98(1): 160-168, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34233032

RESUMO

Sulfur-doped graphitic carbon nitride (S-g-CN) has gained significant attention in recent years. Sulfur-doped graphitic carbon nitride (S-g-CN) is a promising metal-free photocatalyst because of its band orientation, natural abundance and groundwork. Improved photocatalytic activity of S-g-CN material for solar chemical production persists a hot yet challenging problem. Herein, we provide an adaptable method for the synthesis of S-g-CN nanocomposite decorated with the moiety of giant polyoxometalate (S-g-CN/Mo-368) that subsequently showed highly efficient photocatalytic activity. The as-synthesized S-g-CN/Mo-368 as a recyclable artificial photocatalyst revealed excellent activity for solar chemical production, that is nicotinamide adenine dinucleotide (NADH) regeneration under visible light. The immobilized Mo-368 on the S-g-CN surface increased the visible light adsorption capacity of the S-g-CN/Mo-368 photocatalyst. The visible light absorption activity, morphology, element compositions, particle size and zeta potential of S-g-CN powder and S-g-CN/Mo-368 were thoroughly investigated. From the application point of view, S-g-CN/Mo-368 was applied to determine the solar chemical production (i.e. NADH regeneration) under visible light with a higher yield% of about ~ 94.85%.


Assuntos
NAD , Compostos de Nitrogênio , Ânions , Grafite , Luz , Compostos de Nitrogênio/química , Polieletrólitos , Enxofre
18.
J Indian Prosthodont Soc ; 21(3): 295-303, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34380818

RESUMO

Aims: The purpose of this study is to compare and evaluate the failure modes and load-bearing capacity of different surface-treated polyether ether ketone (PEEK) copings when veneered with lithium di-silicate with that of PEEK veneered with composite. Settings and Design: In vitro; comparative study. Materials and Methods: Congruently anatomically shaped single unit PEEK copings (n = 40) were fabricated by scanning a prepared typodont tooth. The PEEK copings were subdivided among four groups (n = 10/group). Among all, one group of PEEK coping was veneered with Urethane dimethacrylate (UDMA)-based composite and other groups were veneered with lithium-di-silicate after different surface treatment on peek copings, i.e., (i) composite veneered PEEK fixed dental prosthesis (FDP) (control group: Group PC), (ii) lithium di-silicate veneered PEEK FDP (no surface treatment: Group PCeN), (iii) lithium di-silicate veneered PEEK FDP (sandblasting with 50 µm alumina: Group PCeS), and (iv) lithium di-silicate veneered PEEK FDP (chemical etching with 98% sulfuric acid: Group PCeE). The load-bearing capacity of all specimens was assessed using a universal test machine. All the samples were loaded till the cracking point and load at that point and failure modes were noted down. Statistical Analysis Used: One-way ANOVA and post hoc Tukey tests. Results: The highest load-bearing capacity was recorded for lithium di-silicate veneered PEEK copings which were chemically etched with 98% sulfuric acid (Group PCeE: 1040.25 ± 77.46) followed by Group PCeS (1017.20 ± 53.70), then Group PC (965 ± 51.57) and least was for Group PCeN (933 ± 97.54). There was a significant reduction in mean load-bearing capacity in Group PCeN (P < 0.05). Conclusions: Veneering of PEEK with pressed lithium di-silicate seems to be a viable clinical option in terms of adequate load-bearing capacity. Lithium di-silicate veneered PEEK FDPs were successful against physiological occlusal forces and are a suitable material for FDPs.


Assuntos
Cetonas , Lítio , Adaptação Psicológica , Benzofenonas , Éteres , Polímeros , Silicatos , Suporte de Carga
19.
Org Lett ; 23(17): 6697-6702, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34387488

RESUMO

Conjugation-extended carbazolophane donors, dicarbazolophanes (DCzp), were designed and synthesized using a multifold stepwise Pd-catalyzed Buchwald-Hartwig amination/ring cyclization process. Furthermore, elaboration of the DCzp core is possible with the introduction of pendant carbazole derivative groups. This provides a way to tune the optoelectronic properties of the thermally activated delayed fluorescence (TADF) compounds DCzpTRZtBu, dtBuCzDCzpTRZtBu, and dMeOCzDCzpTRZtBu. Solution-processed organic light-emitting diodes (OLEDs) were fabricated and achieved a maximum external quantum efficiency (EQEmax) of 8.2% and an EQE of 7.9% at 100 cd/m2.

20.
Photochem Photobiol ; 97(6): 1498-1506, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34097757

RESUMO

An efficient photocatalytic regeneration of nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) has been carried out by two-electron reduction and protonation of NAD+ /NADP+ , induced by photons in the visible light region. This functional artificial photosynthetic counterpart of the complete energy-trapping occurring in natural photosystem I (PS I) is achieved with nitrogen-enrich graphene quantum dot (N-EGQD) as the light-harvesting photocatalyst. In buffer aqueous solution, this compound photo catalytically recycles a rhodium hydride complex of the type [Cp*Rh(bpy)H]+ (Cp* = pentamethylcyclopentadienyl, bpy = 2,2'-bipyridine) which can mediate hydride transfer processes leading to nucleotide co-factor reduction. Very promising yields of 73.31%/78.45% of NADH/NADPH with the excellent thermal stability of N-EGQD photocatalyst is observed. Thus, in this work, an efficient light-harvesting photocatalyst is synthesized for the regeneration of nicotinamide cofactor that has pharmaceuticals application.


Assuntos
Grafite , Pontos Quânticos , NAD/química , NADP/química , Oxirredução
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA