Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros

Banco de datos
Tipo del documento
Asunto de la revista
País de afiliación
Intervalo de año de publicación
1.
Macromol Rapid Commun ; 45(2): e2300484, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37704216

RESUMEN

The imitation of mussels and oysters to create high-performance adhesives is a cutting-edge field. The introduction of inorganic fillers is shown to significantly alter the adhesive's properties, yet the potential of mesoporous materials as fillers in adhesives is overlooked. In this study, the first report on the utilization of mesoporous materials in a biomimetic adhesive system is presented. Incorporating mesoporous silica nanoparticles (MSN) profoundly enhances the adhesion of pyrogallol (PG)-polyethylene imine (PEI) adhesive. As the MSN concentration increases, the adhesion strength to glass substrates undergoes an impressive fivefold improvement, reaching an outstanding 2.5 mPa. The adhesive forms an exceptionally strong bond, to the extent that the glass substrate fractures before joint failure. The comprehensive tests involving various polyphenols, polymers, and fillers reveal an intriguing phenomenon-the molecular structure of polyphenols significantly influences adhesive strength. Steric hindrance emerges as a crucial factor, regulating the balance between π-cation and charge interactions, which significantly impacts the multicomponent assembly of polyphenol-PEI-MSN and, consequently, adhesive strength. This groundbreaking research opens new avenues for the development of novel biomimetic materials.


Asunto(s)
Materiales Biomiméticos , Bivalvos , Animales , Adhesivos/química , Materiales Biomiméticos/química , Polímeros/química , Vidrio
2.
Insecta mundi ; 20232023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36713789

RESUMEN

Analyses of whole genomic shotgun datasets, COI barcodes, morphology, and historical literature suggest that the following 13 butterfly species from the family Hesperiidae (Lepidoptera: Papilionoidea) in Texas, USA are distinct from their closest named relatives and therefore are described as new (type localities are given in parenthesis): Spicauda atelis Grishin, new species (Hidalgo Co., Mission), Urbanus (Urbanus) rickardi Grishin, new species (Hidalgo Co., nr. Madero), Urbanus (Urbanus) oplerorum Grishin, new species (Hidalgo Co., Mission/Madero), Telegonus tsongae Grishin, new species (Starr Co., Roma), Autochton caballo Grishin, new species (Hidalgo Co., 6 mi W of Hidalgo), Epargyreus fractigutta Grishin, new species (Hidalgo Co., McAllen), Aguna mcguirei Grishin, new species (Cameron Co., Brownsville), Polygonus pardus Grishin, new species (Hidalgo Co., McAllen), Arteurotia artistella Grishin, new species (Hidalgo Co., Mission), Heliopetes elonmuski Grishin, new species (Cameron Co., Boca Chica), Hesperia balcones Grishin, new species (Travis Co., Volente), Troyus fabulosus Grishin, new species (Hidalgo Co., Peñitas), and Lerema ochrius Grishin, new species (Hidalgo Co., nr. Relampago). Most of these species are known in the US almost exclusively from the Lower Rio Grande Valley in Texas. Nine of the holotypes were collected in 1971-1975, a banner period for butterfly species newly recorded from the Rio Grande Valley of Texas; five of them collected by William W. McGuire, and one by Nadine M. McGuire. At the time, these new species have been recorded under the names of their close relatives. A Neotype is designated for Papilio fulminator Sepp, [1841] (Suriname). Lectotypes are designated for Goniurus teleus Hübner, 1821 (unknown, likely in South America), Goniloba azul Reakirt, [1867] (Mexico: Veracruz) and Eudamus misitra Plötz, 1881 (Mexico). Several taxonomic changes are proposed. The following taxa are species (not subspecies): Spicauda zalanthus (Plötz, 1880), reinstated status (not Spicauda teleus (Hübner, 1821)), Telegonus fulminator (Sepp, [1841]), reinstated status (not Telegonus fulgerator (Walch, 1775), Telegonus misitra (Plötz, 1881), reinstated status (not Telegonus azul (Reakirt, [1867])), Autochton reducta (Mabille and Boullet, 1919), new status (not Autochton potrillo (Lucas, 1857)), Epargyreus gaumeri Godman and Salvin, 1893, reinstated status (not Epargyreus clavicornis (Herrich-Schäffer, 1869)), and Polygonus punctus E. Bell and W. Comstock, 1948, new status (not Polygonus savigny (Latreille, [1824])). Urbanus ehakernae Burns, 2014 and Epargyreus socus chota Evans, 1952 are junior subjective synonyms of Urbanus alva Evans, 1952 and Epargyreus clavicornis (Herrich-Schäffer, 1869), respectively, and Epargyreus gaumeri tenda Evans, 1955, new combination is not a subspecies of E. clavicornis.

3.
PLoS One ; 16(5): e0252269, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34038489

RESUMEN

BACKGROUND: Restoration of endodontically treated premolar is in high risk for biomechanical failure, and often presents with subgingival margins. Proximal box elevation (PBE) has been used to relocate subgingival cavity outlines. OBJECTIVE: To evaluate the influence of PBE on fracture resistance and gingival microleakage of premolars with endodontic access cavities following ceramic endocrown. METHODS: Eighty sound maxillary premolars with standardized Class II cavities on mesial surfaces were randomly assigned to four groups (n = 20 in each group). Groups E1, E2 and E3, with proximal margins located in dentin/cementum, 2 mm below the cemento-enamel junction (CEJ), simulated subgingival location. Group E4 (supragingival group), with proximal margins located in enamel, 1 mm above the CEJ, was used as the positive control. For margin elevation of the proximal cavities, bulk-fill Smart Dentin Replacement (SDR), a visible light cured resin composite, was applied in group E1, and conventional resin composite (3M Z350 XT, a light-activated composite) was placed in group E2. Group E3 was only treated with a ceramic crown and served as the negative control. In all groups, computer-aided design (CAD) ceramic endocrowns were adhesively inserted, and fracture resistance, failure mode and microleakage were evaluated. RESULTS: A higher fracture resistance value was observed in PBE groups E1 and E2, regardless of the materials used (P = 0.038, and 0.010, respectively, vs E3), and fracture resistance in group E1 was higher than that in group E2. In teeth without PBE, the percentage of catastrophic failures reached 70%. Compared to group E3, a lower frequency distribution of microleakage was detected in supragingival group E4 (P = 0.031). No increased percentage of microleakage was observed in groups treated with PBE. CONCLUSION: For endodontically treated maxillary premolars restored with ceramic endocrowns, PBE increases fracture resistance but not microleakage.


Asunto(s)
Diseño Asistido por Computadora , Diente Premolar/química , Cemento Dental/química , Dentina/química , Humanos , Cementos de Resina/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA