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Introduction: Ethnic identity is an important protective factor for various ethnic groups and developmental periods. Although existing measures assessing ethnic identity are well known, less is known about the measurement invariance of the Multigroup Ethnic Identity Measure (MEIM) across adolescent ethnic groups. The present study evaluates the factor structure of MEIM (Roberts et al., 1999) and tests the measurement invariance across early and middle adolescence and ethnic background (N = 4940).Methods: Data from an ethnic minority sample of youth (54% girls; Mage = 13.88, grades 6th - 12th; 60% African American, 22% multi-ethnic, 8% Latinx, 5% Asian, 5% American Indian) in the United States of America were examined using confirmatory factor analysis (CFA) and multi-group measurement invariance via a structural equation modeling (SEM) framework. Models for invariance were tested using full information maximum likelihood-robust (FIML-R) estimation in Mplus.Results: CFA supported a three-factor solution (i.e., cognitive clarity, behavioral engagement, and affective pride). The model indicated scalar invariance across early and middle adolescence and partial scalar invariance across the five self-identified racial/ethnic minority groups. There were no grade differences on the ethnic identity factors. Among the racial/ethnic groups, multi-ethnic youth reported the lowest levels on all three ethnic identity factors compared to the other groups.Conclusions: Results of this study point to the validity of using the MEIM for meaningful comparisons of ethnic identity across ethnic groups and across early and middle adolescence. Implications for the interpretation and use of this measure with diverse adolescents are discussed. [ABSTRACT FROM AUTHOR]

The spores of 11 species of Lomariocycas that grow in America were studied: Lomariocycas aurata , L. columbiensis , L. cycadifolia , L. insularis , L. magellanica , L. moritziana , L. rufa, L. schomburgkii, L. shaferi , L. underwoodiana and L. werckleana. The study was performed with light microscope (LM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The spores are monolete of 61–100 μm in equatorial diameter and 40–79 μm in polar diameter. The exospore is 1.5–4.8 μm thick and in section is two-layered. The perispore is folded, two types of folds were observed in the different species analyzed and also they could be fused in different ways. In section, it is 0.5–13.8 μm thick and is two-layered. The outer layer is single stratified and the inner layer is three-stratified. The spores of some species are illustrated and described for the first time. Moreover, the sporoderm ultrastructure of L. underwodiana was not studied until now. The differences found in perispore morphology and ultrastructure could be valuable characters for systematic and phylogenetic purposes. • The spores of Lomariocycas from America are folded. • Two types of folds are defined: (1) narrow and high, (2) wide and robust. • The two types of folds could be partially or totally fused. • The spores of some species are illustrated and described for the first time. • In the species analyzed the sporoderm ultrastructure is similar. [ABSTRACT FROM AUTHOR]

The extinct organic-walled dinoflagellate cyst Duosphaeridium rugosum was first described from the Paleocene (Danian) of the southern USA. It has since been documented at several other localities around the world. Well-preserved specimens from the Danian of the Dakhla Formation in the Dababiya Corehole in southern Egypt, illustrated by light and scanning electron microscope images, reveal new morphological details, most notably parasutural features revealing the paratabulation. Detailed observations indicate that Duosphaeridium rugosum has an L-type ventral arrangement, an essentially straight sulcus, and apparently dextral torsion indicating a tentative affinity with the gonyaulacacean subfamily Cribroperidinioideae. Duosphaeridium rugosum occurs in an assemblage with many Danian markers; such as Danea californica, Carpatella cornuta and Lanternosphaeridium reinhardtii. Its earliest or first occurrence is contemporaneous with the upper part of nannoplankton zone NP2 and the uppermost part of the planktonic foraminiferal Parasubbotina pseudobulloides (P1a) zone. Its first occurrence is thus a useful stratigraphical marker for the Danian (earliest Paleocene). Duosphaeridium rugosum is associated with relatively abundant dinoflagellate cyst taxa such as Spiniferites, Achomosphaera, Fibrocysta, Pterodinium, Cordosphaeridium and Exochosphaeridium, which characterize neritic marine settings. [ABSTRACT FROM AUTHOR]

Aim: In vitro evaluation of shear bond strength of composite resin bonded to primary enamel which is pretreated using acid etching and E, Cr:YSGG Laser. Qualitative morphological changes in enamel surfaces were observed under a scanning electron microscope. Materials and Method: Sixty extracted human teeth were divided into two groups of 30 each (Groups A and B). In Group A, prepared surface of enamel was etched using 35% phosphoric acid (Scotchbond Multipurpose 3M ESPE). In Group B, enamel surface was etched using Er, Cr:YSGG Laser beam (Waterlase MD, Biolase, San Clemente,USA). Bonding agent (Adper, single bond 2, 3M ESPE) was applied over the test areas on 20 samples of Groups A and Groups B each light cured. Composite resin core ( Filtek z350 XT, 3M ESPE) was made in increments and light cured. The samples were tested for shear bond strength. Remaining 10 samples from each Group were observed under SEM. Results: The mean shear bond strength with standard deviation values of Group A (18.39 ± 4.75 MPa) and Group B (6.37 ± 2.71 MPa) respectively. Conclusions: Mean shear bond strength of Group A (Acid etching) was significantly higher than the mean shear bond strength of Group B (Laser etching). SEM observations of laser pretreatment showed microretentive surface with the presence of elevations and depressions not adequate to improve the bond strength as compared to Acid etching [ABSTRACT FROM AUTHOR]

Background. The accessibility of the remineralizing ions in teeth's environment is essential for their incorporation into caries-affected dentin. Novel bioglass-reinforced materials capable of releasing fluoride, calcium and phosphates may be particularly useful in the tissue remineralization process. A novel restorative material, ACTIVA BioActive-Restorative (Pulpdent Corp., Watertown, USA), is a hydrophilic resin-modified glassionomer cement (RMGIC) enriched with bioglass particles and fortified with a patented rubberized polymer resin. Its application in restorative dentistry may be significant, promoting remineralization of carious lesions. Objectives. The aim of the study was to compare the fluoride ion release profiles from a bioglass-reinforced RMGIC, a conventional glass-ionomer cement (GIC) and a nanohybrid restorative polymer resin. Material and methods. The quantity of fluoride ions released from ACTIVA, Ketac Molar Quick Aplicap and Tetric EvoCeram was assessed using a fluoride-specific electrode. The surface characteristics of the preand post-experimental specimens were studied using a scanning electron microscope (SEM) and confocal microscope. An X-ray powder diffraction (XRD) analysis was additionally used to examine the chemical compositions of the dental materials. Results. The greatest quantity of fluoride ions was freed from the GIC specimens (20.698-54.118 ppm), followed by the bioglass-reinforced RMGIC (from 1.236 to 15.552 ppm) and nanohybrid polymer resin (0.370-1.148 ppm). The pre-experimental specimens of the bioglass-reinforced RMGIC were porous, while the post-experimental specimens were smoother with visible micro-cracks. The XRD analysis of the bioglass particles confirmed that the material was composed mainly of fluoride (27.70 mass%), silicon (15.62 mass%), aluminum (5.91 mass%), and calcium (5.40 mass%). Conclusions. The fluoride ion release profile of ACTIVA was lower than the GIC Keta Molar Quick Aplicap, but significantly higher than the nanohybrid restorative polymer resin Tetric EvoCeram. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to compare the effect of diode laser, endoActivator, and passive ultrasonics for smear layer removal at the apical third from root canals with 0.2% chitosan. Materials and Methods: A total of 40 mandibular premolars were decoronated to establish a working length of 12 mm and shaped with ProTaper rotary files up to size F3. In Group A, canals were irrigated with 1 ml of 0.2% chitosan. In Group B, canals were initially irrigated with 0.8 ml of 0.2% chitosan and the remaining 0.2 ml was activated with diode laser. In Group C, canals were irrigated with 1 ml of 0.2% chitosan which was activated with endoActivator. In Group D, canals were irrigated with 0.2% chitosan and activated with passive ultrasonics. All samples were finally flushed with 3 ml of distilled water. The percentage of smear layer removal was analyzed with a scanning electron microscope examination at ×1000 and ×3000. Data were analyzed using Statistical Package for the Social Sciences version 16.0 (SPSS Inc., Chicago, IL, USA) at a significance level of P < 0.05. Results: The mean value for Group B when compared to Group C for the removal of smear layer was higher, but there was no statistically significant difference between the two groups (P < 0.068 and P < 0.295). Both Group B and Group C showed a statistically significant difference (P < 0.001) when compared to Group A and Group D for the removal of smear layer. Conclusion: Diode laser and endoActivator with 0.2% chitosan proved better in the removal of the smear layer when compared to passive ultrasonic irrigation. [ABSTRACT FROM AUTHOR]

The laccate (shiny or varnished) Ganoderma contain fungi that are important wood decay fungi of living trees and decomposers of woody debris. They are also an important group of fungi for their degradative enzymes and bioprocessing potential. Laboratory decay microcosms (LDMs) were used to study the relative decay ability of G anoderma curtisii, Ganoderma meredithiae, Ganoderma sessile, and G anoderma zonatum, which are four commonly encountered Ganoderma species in the U.S., across four wood types ( Pinus taeda, Quercus nigra, Q uercus virginiana, and Sabal palmetto ). Generally, all Ganoderma species were able to decay all types of wood tested despite not being associated with only certain wood types in nature. G . sessile, on average caused the most decay across all wood types. Among the wood types tested, water oak ( Q. nigra ) had the most mass loss by all species of Ganoderma . Scanning electron microscopy was used to assess micromorphological decay patterns across all treatments. All Ganoderma species simultaneously decayed wood cells of all wood types demonstrating their ability to attack all cell wall components. However, G. zonatum caused selective delignification in some sclerenchyma fibers of the vascular bundles in palm ( S. palmetto ) as well as in fibers of water oak. In addition, G. zonatum hyphae penetrated fibers of palm and oak wood causing an unusual decay not often observed in basidiomycetes resulting in cavity formation in secondary walls. Cavities within the secondary walls of fibers gradually expanded and coalesced resulting in degradation of the S2 layer. Differences in colony growth rates were observed when Ganoderma species were grown on medium amended with water soluble sapwood extracts from each wood type. G. meredithiae had enhanced growth on all media amended with sapwood extracts, while G. curtisii, G. sessile and G. zonatum had slower growth on loblolly pine extract amended medium. [ABSTRACT FROM AUTHOR]