RESUMO
OBJECTIVE: Stress distribution assessment by finite elements analysis in poly(etheretherketone) (PEEK) implant and abutment as retainers of single crowns in the anterior region. MATERIALS AND METHODS: Five 3D models were created, varying implant/abutment manufacturing materials: titanium (Ti), zirconia (Zr), pure PEEK (PEEKp), carbon fiber-reinforced PEEK (PEEKc), glass fiber-reinforced PEEK (PEEKg). A 50 N load was applied 30o off-axis at the incisal edge of the upper central incisor. The Von Mises stress (σvM) was evaluated on abutment, implant/screw, and minimum principal stress (σmin) and maximum shear stress (τmax) for cortical and cancellous bone. RESULTS: The abutment σvM lowest stress was observed in PEEKp group, being 70% lower than Ti and 74% than Zr. On the implant, PEEKp reduced 68% compared to Ti and a 71% to Zr. In the abutment screws, an increase of at least 33% was found in PEEKc compared to Ti, and of at least 81% to Zr. For cortical bone, the highest τmax values were in the PEEKp group, and a slight increase in stress was observed compared to all PEEK groups with Ti and Zr. For σmin, the highest stress was found in the PEEKc. Stress increased at least 7% in cancellous bone for all PEEK groups. CONCLUSION: Abutments and implants made by PEEKc concentrate less σvM stress, transmitting greater stress to the cortical and medullary bone. CLINICAL RELEVANCE: The best stress distribution in PEEKc components may contribute to decreased stress shielding; in vitro and in vivo research is recommended to investigate this.
Assuntos
Benzofenonas , Coroas , Dente Suporte , Análise do Estresse Dentário , Análise de Elementos Finitos , Cetonas , Teste de Materiais , Polietilenoglicóis , Polímeros , Titânio , Zircônio , Cetonas/química , Polietilenoglicóis/química , Humanos , Zircônio/química , Titânio/química , Fibra de Carbono/química , Projeto do Implante Dentário-Pivô , Incisivo , Materiais Dentários/química , Implantes Dentários para Um Único Dente , Osso Cortical , Vidro/química , Planejamento de Prótese DentáriaAssuntos
Cetonas , Perfumes , Testes de Toxicidade , Animais , Células Cultivadas , Bases de Dados de Compostos Químicos , Feminino , Humanos , Cetonas/química , Cetonas/toxicidade , Masculino , Camundongos , Testes para Micronúcleos , Perfumes/química , Perfumes/toxicidade , Ratos , Reprodução/efeitos dos fármacos , Absorção Cutânea , Testes CutâneosRESUMO
An inexpensive and highly efficient metal-free alternative to commonly used Ru- and Ir-based catalysts was proposed. It was shown that the new 2,7-di-tert-butyl-5,10-bis(4-trifluoromethylphenyl)-5,10-dihydrophenazine outcompeted the iridium phenylpyridyl complex in photoredox activity in the alkylation of silyl enol ethers yielding aryl alkyl ketones. The reaction occurred under visible light irradiation at room temperature and was also applicable to drug derivatives (ibuprofen and naproxen). In-depth photophysical, electrochemical, and quantum chemical studies showed that the aforementioned N,N-diaryldihydrophenazine exhibited enhanced properties that were essential for the photoredox catalysis (a long-lived triplet excited state, strong reducing ability, high stability of the radical cations formed in single-electron-transfer event, and chemical inertness of the catalyst with respect to reactants). Importantly, the substituted N,N'-diaryldihydrophenazines could be obtained directly from diaryl amines; a facile, easily handled and scaled-up one-pot synthetic procedure was elaborated.
Assuntos
Complexos de Coordenação , Oxirredução , Cetonas/química , Análise Custo-Benefício , Alquilação , CatáliseAssuntos
Cetonas/toxicidade , Compostos Macrocíclicos/toxicidade , Odorantes , Animais , Qualidade de Produtos para o Consumidor , Bases de Dados de Compostos Químicos , Vias de Administração de Medicamentos , Determinação de Ponto Final , Humanos , Cetonas/química , Compostos Macrocíclicos/química , Estrutura Molecular , Nível de Efeito Adverso não Observado , Perfumes , Medição de Risco , Testes de ToxicidadeAssuntos
Cetonas/toxicidade , Odorantes , Animais , Qualidade de Produtos para o Consumidor , Bases de Dados de Compostos Químicos , Vias de Administração de Medicamentos , Determinação de Ponto Final , Humanos , Cetonas/química , Estrutura Molecular , Nível de Efeito Adverso não Observado , Perfumes , Medição de Risco , Testes de ToxicidadeAssuntos
Cetonas , Perfumes , Animais , Células Cultivadas , Bases de Dados de Compostos Químicos , Feminino , Humanos , Cetonas/química , Cetonas/toxicidade , Masculino , Perfumes/química , Perfumes/toxicidade , Ratos , Sistema de Registros , Pele/efeitos dos fármacos , Pele/metabolismo , Absorção Cutânea , Testes de ToxicidadeAssuntos
Cetonas/toxicidade , Odorantes , Animais , Poluentes Ambientais/toxicidade , Humanos , Cetonas/química , Mutagênicos/toxicidade , Nível de Efeito Adverso não Observado , Reprodução/efeitos dos fármacos , Sistema Respiratório/efeitos dos fármacos , Medição de Risco , Pele/efeitos dos fármacos , Testes de ToxicidadeRESUMO
Species-specific behavior-modifying chemicals have been used for more than 50 years for monitoring and management of insect pests of agriculture and human health. Elaterid beetle larvae are among insect pests in soil that are increasingly problematic, in part due to the lack of effective management strategies. However, little is known about the insect-produced chemicals that mediate the reproductive behavior of these pests. We used chemical and behavioral studies to identify, synthesize, and field test the sex attractant pheromone of adults of Melanotus communis, commonly called the corn wireworm, the larvae of which are economically important pests of U.S. crops. Our results indicated that a single female-produced chemical, 13-tetradecenyl acetate, was strongly attractive to conspecific male beetles, and did not appear to attract other species. In field evaluations, male M. communis exhibited a dose-dependent response to this compound. In a trial comparing different slow-release dispensers, a small rubber septum impregnated with the chemical was as effective as and easier to use than a plastic bag dispenser. Given that the sex attractant of this insect consists of a single compound that can be readily synthesized, its development for monitoring and management of the corn wireworm may be economically feasible.
Assuntos
Alcinos/química , Alcinos/metabolismo , Besouros/metabolismo , Cetonas/química , Cetonas/metabolismo , Atrativos Sexuais/biossíntese , Atrativos Sexuais/química , Alcinos/farmacologia , Animais , Bioensaio , Besouros/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Cetonas/farmacologia , Masculino , Atrativos Sexuais/farmacologiaRESUMO
There are insufficient toxicity data on the target material propanal diethyl acetal (CAS # 4744-08-5). Hence, in silico evaluation was conducted to determine read-across analogs for this material. Based on structural similarity, reactivity, metabolism data, physical-chemical properties, and expert judgment, analogs acetal (CAS # 105-57-7) and butane, 1,1'-[methylenebis(oxy)]bis- (CAS # 2568-90-3) were identified as read-across materials with sufficient data for toxicological evaluation of genotoxicity.