Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
J Dent Sci ; 19(4): 2262-2267, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39347065

RESUMO

Background/purpose: Large language models (LLMs) such as OpenAI's ChatGPT, Google's Bard, and Microsoft's Bing Chat have shown potential as educational tools in the medical and dental fields. This study evaluated their effectiveness using questions from the Japanese national dental hygienist examination, focusing on textual information only. Materials and methods: We analyzed 73 questions from the 32nd Japanese national dental hygienist examination, conducted in March 2023, using LLMs ChatGPT-3.5, GPT-4, Bard, and Bing Chat. Each question was categorized into one of nine domains. Standardized prompts were used for all LLMs, and Fisher's exact test was applied for statistical analysis. Results: GPT-4 achieved the highest accuracy (75.3%), followed by Bing (68.5%), Bard (66.7%), and GPT-3.5 (63.0%). There were no statistically significant differences between the LLMs. The performance varied across different question categories, with all models excelling in the 'Disease mechanism and promotion of recovery process' category (100% accuracy). GPT-4 generally outperformed other models, especially in multi-answer questions. Conclusion: GPT-4 demonstrated the highest overall accuracy among the LLMs tested, indicating its superior potential as an educational support tool in dental hygiene studies. The study highlights the varied performance of different LLMs across various question categories. While GPT-4 is currently the most effective, the capabilities of LLMs in educational settings are subject to continual change and improvement.

2.
J Dent Sci ; 19(3): 1595-1600, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39035269

RESUMO

Background/purpose: Rapid advancements in AI technology have led to significant interest in its application across various fields, including medicine and dentistry. This study aimed to assess the capabilities of ChatGPT-4V with image recognition in answering image-based questions from the Japanese National Dental Examination (JNDE) to explore its potential as an educational support tool for dental students. Materials and methods: The dataset used questions from the JNDE, which was conducted in January 2023, with a focus on image-related queries. ChatGPT-4V was utilized, and standardized prompts, question texts, and images were input. Data and statistical analyses were conducted using Qlik Sense® and GraphPad Prism. Results: The overall correct response rate of ChatGPT-4V for image-based JNDE questions was 35.0 %. The correct response rates were 57.1 % for compulsory questions, 43.6 % for general questions, and 28.6 % for clinical practical questions. In specialties like Dental Anesthesiology and Endodontics, ChatGPT-4V achieved correct response rates above 70 %, while response rates for Orthodontics and Oral Surgery were lower. A higher number of images in questions was correlated with lower accuracy, suggesting an impact of the number of images on correct and incorrect responses. Conclusion: While innovative, ChatGPT-4V's image recognition feature exhibited limitations, especially in handling image-intensive and complex clinical practical questions, and is not yet fully suitable as an educational support tool for dental students at its current stage. Further technological refinement and re-evaluation with a broader dataset are recommended.

3.
J Dent Sci ; 19(3): 1811-1818, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39035336

RESUMO

Background/purpose: There are reports on the relationship between periodontal treatment and the whole body. The purpose of the present study was to investigate the effect of periodontal initial treatment on brain function activity by improving periodontal tissue and the occlusal status of subjects with periodontitis. Materials and methods: The subjects were 13 patients with periodontitis. Following the patient's informed written consent, the periodontal initial treatment provided to the patient included tooth brushing instruction, scaling and root planning, however, occlusal adjustment was not performed at this stage. Periodontal examination, occlusal force examination and fMRI results were also evaluated at the initial and the reevaluation examinations. Results: After the periodontal initial treatment had been performed, periodontal tissue had significantly improved. In addition, cerebral blood flow in the insula and primary motor cortex was also improved, as confirmed by fMRI. Conclusion: This result suggests that the periodontal ligament has recovered and the periodontal ligament neuron have been further subjected to clenching in the insula.

4.
J Chem Phys ; 159(24)2023 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-38131482

RESUMO

Although it plays a critical role in the photophysics and catalysis of lanthanides, spin-orbit coupling of electrons on individual lanthanide atoms in small clusters is not well understood. The major objective of this work is to probe such coupling of the praseodymium (Pr) 4f and 6s electrons in Pr2O2 and Pr2O2+. The approach combines mass-analyzed threshold ionization spectroscopy and spin-orbit multiconfiguration second-order quasi-degenerate perturbation theory. The energies of six ionization transitions are precisely measured; the adiabatic ionization energy of the neutral cluster is 38 045 (5) cm-1. Most of the electronic states involved in these transitions are identified as spin-orbit coupled states consisting of two or more electron spins. The electron configurations of these states are 4f46s2 for the neutral cluster and 4f46s for the singly charged cation, both in planar rhombus-type structures. The spin-orbit splitting due to the coupling of the electrons on the separate Pr atoms is on the order of hundreds of wavenumbers.

5.
J Am Chem Soc ; 145(40): 21729-21732, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37650604

RESUMO

Sulfite reduction by dissimilatory sulfite reductases is a key process in the global sulfur cycle. Sulfite reductases catalyze the 6e- reduction of SO32- to H2S using eight protons (SO32- + 8H+ + 6e- → H2S + 3H2O). However, detailed research into the reductive conversion of sulfite on transition-metal-based complexes remains unexplored. As part of our ongoing research into reproducing the function of reductases using dinuclear ruthenium complex {(TpRu)2(µ-Cl)(µ-pz)} (Tp = HB(pyrazolyl)3), we have targeted the function of sulfite reductase. The isolation of a key SO-bridged complex, followed by a sulfite-bridged complex, eventually resulted in a stepwise sulfite reduction. The reduction of a sulfite to a sulfur monoxide using 4H+ and 4e-, which was followed by conversion of the sulfur monoxide to a disulfide with concomitant consumption of 2H+ and 2e-, proceeded on the same platform. Finally, the production of H2S from the disulfide-bridged complex was achieved.

6.
Molecules ; 28(6)2023 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-36985740

RESUMO

To gain insight into the effect of Si/C arrangement on the molecular framework of strained polyhedral compounds, dodecahedrane analogues containing equal numbers of carbon and silicon (Si/C equally mixed dodecahedrane analogues) were investigated using the ab initio molecular orbital method. There are 1648 isomers for which the Si/C arrangement on the molecular framework is different. Based on the geometry optimization of all the isomers as well as the carbon and silicon analogues, the characteristics of the structure, relative energy, and strain energy of the Si/C equally mixed compounds are presented. Then, important factors controlling the relative energy, such as strain energy, are proposed through regression analysis. Also discussed is the correlation between the relative energy and the indices of Si/C dispersion, such as the number of skeletal C-Si single bonds and condensed five-membered rings constituting the polyhedral structure.

7.
J Chem Phys ; 157(11): 114304, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36137790

RESUMO

The precise ionization energy of praseodymium oxide (PrO) seeded in supersonic molecular beams is measured with mass-analyzed threshold ionization (MATI) spectroscopy. A total of 33 spin-orbit (SO) states of PrO and 23 SO states of PrO+ are predicted by second-order multiconfigurational quasi-degenerate perturbation (MCQDPT2) theory. Electronic transitions from four low-energy SO levels of the neutral molecule to the ground state of the singly charged cation are identified by combining the MATI spectroscopic measurements with the MCQDPT2 calculations. The precise ionization energy is used to reassess the ionization energies and the reaction enthalpies of the Pr + O → PrO+ + e- chemi-ionization reaction reported in the literature. An empirical formula that uses atomic electronic parameters is proposed to predict the ionization energies of lanthanide monoxides, and the empirical calculations match well with available precise experimental measurements.

8.
Case Rep Dent ; 2022: 5383893, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35527723

RESUMO

Objective: In this study, we have introduced a case in which the effective blood oxygenation level-dependent signal on functional magnetic resonance imaging (fMRI) was altered by the improvement of periodontal tissue and occlusal function in a patient with periodontitis Stage II Grade B. Material and Methods. A 61-year-old female patient requiring periodontal treatment was diagnosed as having periodontitis Stage II Grade B via clinical and radiographic examinations. Her past medical history included type 2 diabetes, hypertension, and hyperlipidemia. Following the patient's informed written consent, the periodontal initial treatment provided to the patient included tooth brushing instruction and scaling and root planing; however, occlusal adjustment was not performed at this stage. Occlusal force and fMRI results were also evaluated at the initial and reevaluation examinations. Results: After the periodontal initial treatment had been performed, it was noted that the patient's periodontal tissue and occlusal force had improved. It was also evident from fMRI that cerebral blood flow had been activated in the insula, primary motor cortex, and premotor cortex. Conclusion: This result suggested that the periodontal ligament had recovered and the periodontal ligament neuron had been further subjected to clenching in the insula so that the muscle spindle sensation impacted the motor cortex.

9.
Phys Chem Chem Phys ; 24(13): 7739-7747, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35293902

RESUMO

Adsorption and chemical reactions occurring on industrially important ZSM-5 and faujasite zeolite catalysts are investigated with the quantum-mechanical fragment molecular orbital method combined with periodic boundary conditions. Suitable fragmentation patterns are devised and tested providing important case studies of computing real materials with fragmentation methods. A good accuracy is demonstrated in comparison to full calculations, and a good agreement with the available experimental data is obtained. The full production cycle of p-xylene on faujasite zeolite is mapped. The catalytic role of the zeolite in the dehydration reaction, analyzed with the partition analysis, is attributed to the delocalization of the negative charge over the zeolite. On the other hand, an increase of the barrier in the Diels-Alder reaction by the zeolite is attributed to the preferential stabilization of the reactants over the transition state as demonstrated by the guest-zeolite interaction energy.

10.
J Phys Chem Lett ; 13(6): 1596-1601, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35142207

RESUMO

A decomposition of the free energy is developed in the many-body expansion framework of the fragment molecular orbital (FMO) method combined with umbrella sampling molecular dynamics (MD). In FMO/MD simulations, performed with density-functional tight-binding and periodic boundary conditions, all atoms are treated quantum mechanically. The free energy is computed and decomposed for a series of SN2 Menshutkin reactions in water. The barrier lowering by the solvent is attributed to the competition between the solvent polarization and the solute-solvent interactions including charge transfer.

11.
J Phys Chem A ; 126(6): 957-969, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35080391

RESUMO

For gaining insights into interactions in periodic systems, an analysis is developed based on the fragment molecular orbital method combined with periodic boundary conditions. The adsorption energy is decomposed into guest and surface polarization and deformation energy, guest-surface and guest-guest interactions, and the vibrational free energy. The analysis is applied to the adsorption of guest molecules to Ih (001) ice surface. The cooperativity effects result in a non-linear change in the adsorption energy with coverage due to many-body effects. The role of dispersion is found to be dominant for guests with long hydrophobic tails. A rule is proposed relating the length of the alkyl tail with the formation of the guest layer. The computed binding enthalpies are in good agreement with experimental values. For high coverage, adsorbed molecules can form an ordered layer known as self-assembled monolayer.

12.
J Dent Sci ; 17(1): 42-48, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34457200

RESUMO

BACKGROUND/PURPOSE: In Japan, medical and dental care is provided by the universal health insurance system. The Ministry of Health, Labour, and Welfare (MHLW) in Japan sets the rules for health care services provided by health insurance. The MHLW issued a notice in 2020 permitting telemedicine and dental telemedicine for the first visit and for follow-up visits to prevent the spread of COVID-19 infection. We conducted this study to clarify the status of dental telemedicine during 2020. MATERIALS AND METHODS: We used data from lists obtained on the MHLW website in the analysis. We investigated the number of dental institutions conducing dental telemedicine for the first visit and for follow-up visits by prefecture. RESULTS: In each prefecture, fewer dental institutions conducted telemedicine for the first visit than for follow-up visits. Regions with large metropolitan areas had higher numbers of dental institutions conducting dental telemedicine for the first visit and follow-up visits. Private dental clinics provided the largest proportion of dental telemedicine for the first visit, and general hospitals provided the largest proportion for follow-up visits. CONCLUSION: Our study findings indicated that many dental institutions in Japan made efforts to provide dental services via dental telemedicine using the telephone or online with video to help prevent the spread of COVID-19 infection. Dental telemedicine can help patients to access dental services and dental care, thereby expanding the potential of dental telemedicine in Japan.

13.
J Phys Chem Lett ; 12(36): 8757-8762, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34478310

RESUMO

A fast quantum-mechanical approach, density-functional tight-binding combined with the fragment molecular orbital method and periodic boundary conditions, is used to optimize atomic coordinates and cell parameters for a set of protein crystals: 1ETL, 5OQZ, 3Q8J, 1CBN, and 2VB1. Good agreement between experimental and calculated structures is obtained for both atomic coordinates and cell parameters. Sterical clashes present in the experimental structures are corrected by simulations. The partition analysis is extended to treat periodic boundary conditions and applied to analyze protein-solvent interactions in crystals.


Assuntos
Proteínas/química , Simulação por Computador , Cristalização , Ligação de Hidrogênio , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Solventes/química
14.
J Comput Chem ; 42(25): 1817-1825, 2021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-34264536

RESUMO

To explore the characteristics of group 14 elements in sp3 and sp2 hybrid environments systematically, the concept of fragment structure energy (FSE) was proposed through ab initio molecular orbital method. A fragment in this study means a building block of molecular structure and the energy of each kind of fragments (FSE) is obtained from the total electronic energy of different size of model compounds by just a simple algebraic method. The model compounds are the hydrogen-terminated diamond and graphene analogs as the typical compounds in the ideal sp3 - and sp2 -environment, respectively. As a result, the sp3 environment was found to be more stable than the sp2 for all the group 14 elements (C-Pb) in the ideal hybrid environment. Furthermore, a mixing effect of carbon and heavier group 14 elements (E = Si, Ge, Sn, and Pb) was investigated by comparing the E/C-alternately mixed- and the pure FSEs.

15.
J Oral Sci ; 62(2): 189-196, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32132326

RESUMO

Studies suggest that analysis of gingival crevicular fluid (GCF) is useful for evaluating periodontal status. In this study, clinical variables related to tooth mobility, and multiple cytokine levels in proximate GCF, were measured at four time points during initial periodontal treatment: before treatment (baseline), after supragingival scaling, after occlusal adjustment, and after scaling and root planing (SRP); 20 teeth from 13 patients with periodontitis were included. Baseline interleukin (IL)-10 level in GCF was significantly higher around teeth that showed substantial improvement in periodontal epithelial surface area (PESA) after SRP than around teeth without PESA improvement. IL-3 and IL-16 levels in GCF at baseline were significantly higher around teeth with a periodontal inflamed surface area (PISA) of 0 mm2 after SRP than around teeth without PISA improvement. In addition, baseline IL-7, IL-11, and IL-12p40 levels in GCF were significantly lower around teeth with decreased mobility after occlusal adjustment than around teeth without decreased mobility. These results suggest that pre-treatment cytokine levels in GCF are useful in predicting the effects of initial periodontal treatment.


Assuntos
Líquido do Sulco Gengival , Periodontite , Raspagem Dentária , Humanos , Aplainamento Radicular
16.
J Comput Chem ; 40(3): 581-590, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30575087

RESUMO

There are various nonplanar heteroatom analogues of benzene-cyclic 6π electron systems-and among them, hexasilabenzene (Si6 H6 ) is well known as a typical example. To determine the factors that control their planarity, quantum chemical calculations and an energy component analysis were performed. The results show that the energy components mainly controlling the planarity of benzene and hexasilabenzene are different. For hexasilabenzene, electron repulsion energy was found to be significantly important for the planarity. The application of the pseudo Jahn-Teller effect and the Carter-Goddard-Malrieu-Trinquier model for the interpretation of the planarity of the benzene analogues was also investigated. Furthermore, based on the quantitative results, it was revealed that the planarization of hexasilabenzene is realized by introducing substituents with π-accepting ability, such as the boryl group, that bring about a reduction of the π-electron repulsion on the silicon skeleton. © 2018 Wiley Periodicals, Inc.

17.
J Periodontal Res ; 40(1): 67-72, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15613082

RESUMO

OBJECTIVE: The central effects of nicotine on gingival blood flow and vascular conductance were investigated. BACKGROUND: Nicotine is absorbed in cigarette smoking, which is a risk factor for periodontal disease. Although studies have shown peripheral effects of nicotine on gingival blood flow and gingival vascular conductance, little is known about its central effects. METHODS: We used laser Doppler flow measurements to investigate the changes of gingival blood flow produced by 5 min intracerebroventricular (i.c.v.) injection of (-)-nicotine ditartrate in rats anesthetized by urethane and alpha-chloralose, along with occasional measurements of the blood pressure from the femoral artery. RESULTS: The i.c.v. injection of nicotine at 15, 50, and 150 microg reduced the gingival blood flow significantly, compared with saline. The maximal reduction was dose-dependent. Next, we measured the blood pressure and gingival blood flow in the i.c.v. injection of nicotine at 50 microg, to calculate the gingival vascular conductance. The blood pressure was reduced, along with the change of gingival blood flow immediately after the injection, whereas the gingival vascular conductance fell with a time-lag. CONCLUSION: These results suggest that the reduction of gingival blood flow by central nicotinic stimulation is accompanied in part by a change of vascular tonus in the gingiva.


Assuntos
Gengiva/efeitos dos fármacos , Nicotina/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Gengiva/irrigação sanguínea , Fluxometria por Laser-Doppler , Masculino , Nicotina/efeitos adversos , Ratos , Ratos Wistar , Fluxo Sanguíneo Regional
18.
Auton Neurosci ; 108(1-2): 87-90, 2003 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-14614969

RESUMO

The sensitivity of subfornical organ (SFO) neurons in rat slice preparations to nicotine was studied using whole-cell patch-clamp recordings and immunohistochemistry. In the current-clamp mode, nicotine at 10 microM depolarized the membrane and increased the firing rate. In the voltage-clamp mode, nicotine elicited inward currents in a dose-dependent manner. The net current-voltage relationships of the nicotine-induced currents displayed inward rectification above -40 mV. The relatively alpha4beta2-selective nicotinic acetylcholine (ACh) receptor antagonist, dihydro-beta-erythroidine, reduced the peak amplitudes of the nicotine-induced inward currents. Immunohistochemical experiments with alpha4 antibody showed the existence of immunopositive cells in the subfornical organ. These results suggest that neurons in the subfornical organ are excited via alpha4beta2 nicotinic acetylcholine receptors.


Assuntos
Receptores Nicotínicos/fisiologia , Órgão Subfornical/fisiologia , Animais , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Neurônios/química , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Agonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/farmacologia , Ratos , Ratos Wistar , Receptores Nicotínicos/análise , Órgão Subfornical/química , Órgão Subfornical/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA