RESUMO
Matrix vesicles (MVs) are a special class of extracellular vesicles released by mineralizing cells during bone and tooth mineralization that initiate the precipitation of apatitic minerals by regulating the extracellular ratio between inorganic phosphate (Pi), a calcification promoter, and pyrophosphate (PPi), a calcification inhibitor. The Pi/PPi ratio is thought to be controlled by two ecto-phosphatases present on the outer leaflet of the MVs' membrane: ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) that produces PPi as well as Pi from ATP and tissue-nonspecific alkaline phosphatase (TNAP) that hydrolyzes both ATP and PPi to generate Pi. However, if and how these enzymes act in concert in MVs are still unclear. Herein, we investigated the role of NPP1 and TNAP in ATP hydrolysis during MV-mediated biomineralization using proteoliposomes as a biomimetic model for MVs. Proteoliposomes composed by 1,2-dipalmitoylphosphatidylcholine (DPPC) and harboring NPP1 alone, TNAP alone, or both together at different molar ratios (1:1, 10:1, and 1:10) were fabricated. After 48 h of incubation with ATP, TNAP-containing proteoliposomes consumed more ATP than NPP1-containing vesicles (270 and 210 nmol, respectively). Both types of vesicles comparatively formed ADP (205 and 201 nmol, respectively), while NPP1-containing vesicles hydrolyzed AMP less efficiently than TNAP-containing proteoliposomes (10 and 25 nmol, respectively). In vitro mineralization assays showed that in the presence of ATP, TNAP-harboring proteoliposomes mineralized through a sigmoidal single-step process, while NPP1-harboring vesicles displayed a two-step mineralization process. ATR-FTIR analyses showed that the minerals produced by TNAP-harboring proteoliposomes were structurally more similar to hydroxyapatite than those produced by NPP1-harboring vesicles. Our results with proteoliposomes indicate that the pyrophosphohydrolase function of NPP1 and the phosphohydrolase activity of TNAP act synergistically to produce a Pi/PPi ratio conducive to mineralization and the synergism is maximal when the two enzymes are present at equimolar concentrations. The significance of these findings for hypophosphatasia is discussed.
Assuntos
Fosfatase Alcalina , Calcinose , Humanos , Fosfatase Alcalina/metabolismo , Biomineralização , Osso e Ossos/metabolismo , Minerais , Trifosfato de AdenosinaRESUMO
Dental decay is known in the world as the most common human infectious disease. Ascending process of dental caries index in the world shows the failure of oral disease prevention. Streptococcus mutans bacteria cause acid damage and tooth decay by producing acid over time. Nanomaterials with suitable functionality, high permeability, extremely large surface area, significant reactivity, unique mechanical features, and non-bacterial resistance can be considered as promising agents for antimicrobial and antiviral applications. In this study, nickel oxide (NiO) nanoparticles with size range from 2 to 16 nm containing Stevia natural sweetener were eco-friendly synthesized via a simple method. Additionally, their various concentrations were evaluated on S. mutans bacteria by applying the broth dilution method. The results demonstrated that these spherical NiO nanoparticles had efficient bacteriostatic activity on this gram-positive coccus.
Assuntos
Cárie Dentária , Nanopartículas , Antibacterianos/farmacologia , Biofilmes , Humanos , Testes de Sensibilidade Microbiana , Níquel , Extratos Vegetais/farmacologia , Streptococcus mutansRESUMO
PURPOSE: This article presents a systematic, step-by-step checklist approach to be used for contouring and polishing anterior resin composite restorations to achieve maximum esthetics efficiently. CLINICAL CONSIDERATIONS: This checklist is intended to be used to take the guesswork out and streamline the process to predictably, practically, and repeatedly contour and polish anterior resin composite restorations. The practitioner's knowledge of basic dental anatomy combined with this step-by-step checklist facilitates identifying and modifying the final restoration to an anatomically correct form, thus satisfying the most esthetically demanding patients. This approach is demonstrated with case presentation of direct resin veneers in a young female, which resulted in an improved smile that satisfied her esthetic desires. CONCLUSIONS: The use of standardized protocols facilitates and expedites daily procedures in dentistry. Specifically, this checklist protocol, which is geared towards contouring and polishing anterior direct resin composite restorations. CLINICAL SIGNIFICANCE: The clinical technique presented in this article shows the advantages of using a step-by-step checklist approach to predictably and efficiently obtain ideal esthetics when performing anterior resin composite restorations.
Assuntos
Lista de Checagem , Polimento Dentário , Resinas Compostas , Restauração Dentária Permanente , Estética Dentária , Feminino , Humanos , PolôniaRESUMO
The aim of this study was to investigate the influence of the production method and the polymeric carrier on the ability to generate and maintain the supersaturation of a poorly soluble drug in biorelevant medium. The amorphous solid dispersion of sulfamethoxazole, an antibacterial drug, was produced using two different polymers by spray-drying or hot melt extrusion methods. When Eudragit EPO was used, supersaturation was maintained up to 24 h for both techniques at all drug-polymer proportions. However, when Soluplus was employed in hot melt extrusion, a smaller amount of drug was dissolved when compared to the amorphous drug. The proportion of 3:7 drug-Eudragit EPO (w/w) produced by spray-drying presented a higher amount of drug dissolved in supersaturation studies and it was able to maintain the physical stability under different storage conditions throughout the 90-day evaluation. Supersaturation generation and system stability were found to be related to more effective chemical interaction between the polymer and the drug provided by the production method, as revealed by the 1D ROESY NMR experiment. Investigation of drug-polymer interaction is critical in supersaturating drug delivery systems to avoid crystallization of the drug and to predict the effectiveness of the system. Chemical compounds studied in this article: Sulfamethoxazole (PubChem CID: 4539) and Methacrylate copolymer - Eudragit EPO (PubChem CID: 65358).
Assuntos
Preparações Farmacêuticas/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Polivinil/química , Cristalização , Dessecação , Portadores de Fármacos/química , Composição de Medicamentos/métodos , Interações Medicamentosas , Estabilidade de Medicamentos , SolubilidadeRESUMO
BACKGROUND: Dentigerous cyst (DC) occurs in approximately 20% of jaw cysts, being the second major common odontogenic cyst, after radicular cyst. This oral lesion has the ability to destroy maxillary bones and could be the origin of several odontogenic tumors. However, molecules implicated in its pathogenesis as well as those involved in its neoplastic transformation remain unknown. Here, we established a cell population derived from a DC as an in vitro model for the study of this oral lesion. METHODS: Cell culture was performed from a DC from a 44-year-old male. Cells were cultured at 37°C in DMEM/F12 medium containing 10% fetal bovine serum. Expression of epithelial markers was analyzed by Western blot and immunofluorescence. Ultrastructural characterization was carried out by transmission electron microscopy. Conditioned media were obtained and characterized by zymography and Western blot. RESULTS: Cells showed spindle-shaped morphology, but they express epithelial markers, such as cytokeratins and the odontogenic ameloblast-associated protein. The ultrastructural analysis showed well-formed desmosomes present in adhering contiguous cells, confirming the epithelial lineage of this cell population. Cells also contain several vesicles adjacent to plasma membrane, suggesting an active secretion. Indeed, the analysis of the conditioned medium revealed the presence of several secreted proteins, among them the matrix metalloproteinase-2. CONCLUSIONS: Our work provides a useful model to identify the molecular mechanisms involved in the pathogenesis of DC.
Assuntos
Cisto Dentígero/patologia , Doenças Maxilares/patologia , Adulto , Western Blotting , Células Cultivadas , Imunofluorescência , Humanos , Masculino , Maxila/citologia , Maxila/patologiaRESUMO
Sixteen yeast isolates identified as belonging to the genus Sugiyamaella were studied in relation to D-xylose fermentation, xylitol production, and xylanase activities. The yeasts were recovered from rotting wood and sugarcane bagasse samples in different Brazilian regions. Sequence analyses of the internal transcribed spacer (ITS) region and the D1/D2 domains of large subunit rRNA gene showed that these isolates belong to seven new species. The species are described here as Sugiyamaella ayubii f.a., sp. nov. (UFMG-CM-Y607T = CBS 14108T), Sugiyamaella bahiana f.a., sp. nov. (UFMG-CM-Y304T = CBS 13474T), Sugiyamaella bonitensis f.a., sp. nov. (UFMG-CM-Y608T = CBS 14270T), Sugiyamaella carassensis f.a., sp. nov. (UFMG-CM-Y606T = CBS 14107T), Sugiyamaella ligni f.a., sp. nov. (UFMG-CM-Y295T = CBS 13482T), Sugiyamaella valenteae f.a., sp. nov. (UFMG-CM-Y609T = CBS 14109T) and Sugiyamaella xylolytica f.a., sp. nov. (UFMG-CM-Y348T = CBS 13493T). Strains of the described species S. boreocaroliniensis, S. lignohabitans, S. novakii and S. xylanicola, isolated from rotting wood of Brazilian ecosystems, were also compared for traits relevant to xylose metabolism. S. valenteae sp. nov., S. xylolytica sp. nov., S. bahiana sp. nov., S. bonitensis sp. nov., S. boreocarolinensis, S. lignohabitans and S. xylanicola were able to ferment D-xylose to ethanol. Xylitol production was observed for all Sugiyamaella species studied, except for S. ayubii sp. nov. All species studied showed xylanolytic activity, with S. xylanicola, S. lignohabitans and S. valenteae sp. nov. having the highest values. Our results suggest these Sugiyamaella species have good potential for biotechnological applications.
Assuntos
Endo-1,4-beta-Xilanases/metabolismo , Saccharomycetales/isolamento & purificação , Saccharum/microbiologia , Xilitol/metabolismo , Xilose/metabolismo , Brasil , Celulose/metabolismo , Endo-1,4-beta-Xilanases/genética , Etanol/metabolismo , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Saccharomycetales/classificação , Saccharomycetales/genética , Saccharomycetales/metabolismo , Madeira/microbiologiaRESUMO
Conventional pathogen detection methods require trained personnel, specialized laboratories and can take days to provide a result. Thus, portable biosensors with rapid detection response are vital for the current needs for in-loco quality assays. In this work the authors analyze the characteristics of an immunosensor based on the evanescent field in plastic optical fibers with macro curvature by comparing experimental with simulated results. The work studies different shapes of evanescent-wave based fiber optic sensors, adopting a computational modeling to evaluate the probes with the best sensitivity. The simulation showed that for a U-Shaped sensor, the best results can be achieved with a sensor of 980 µm diameter by 5.0 mm in curvature for refractive index sensing, whereas the meander-shaped sensor with 250 µm in diameter with radius of curvature of 1.5 mm, showed better sensitivity for either bacteria and refractive index (RI) sensing. Then, an immunosensor was developed, firstly to measure refractive index and after that, functionalized to detect Escherichia coli. Based on the results with the simulation, we conducted studies with a real sensor for RI measurements and for Escherichia coli detection aiming to establish the best diameter and curvature radius in order to obtain an optimized sensor. On comparing the experimental results with predictions made from the modelling, good agreements were obtained. The simulations performed allowed the evaluation of new geometric configurations of biosensors that can be easily constructed and that promise improved sensitivity.
Assuntos
Fibras Ópticas , Técnicas Biossensoriais , Escherichia coli , Tecnologia de Fibra Óptica , Imunoensaio , PlásticosRESUMO
BACKGROUND: Acute kidney injury (AKI) is a growing global concern and often reversible. Saliva urea nitrogen (SUN) measured by a dipstick may allow rapid diagnosis. We studied longitudinal agreement between SUN and blood urea nitrogen (BUN) and the diagnostic performance of both. METHODS: Agreement between SUN and BUN and diagnostic performance to diagnose AKI severity in AKI patients in the United States and Brazil were studied. Bland-Altman analysis and linear mixed effects models were employed to test the agreement between SUN and BUN. Receiver operating characteristics statistics were used to test the diagnostic performance to diagnose AKI severity. RESULTS: We found an underestimation of BUN by SUN, decreasing with increasing BUN levels in 37 studied patients, consistent on all observation days. The diagnostic performance of SUN (AUC 0.81, 95% CI 0.63-0.98) was comparable to BUN (AUC 0.85, 95% CI 0.71-0.98). CONCLUSION: SUN reflects BUN especially in severe AKI. It also allows monitoring treatment responses. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=445041.
Assuntos
Injúria Renal Aguda/diagnóstico , Nitrogênio da Ureia Sanguínea , Saliva/química , Ureia/análise , Adulto , Brasil , Gerenciamento Clínico , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Nitrogênio/análise , Estudos Prospectivos , Estados Unidos , Ureia/sangue , Ureia/urinaRESUMO
A modified simplex algorithm was used to optimize a system of preconcentration for cadmium determination in samples of sediments, cigarettes and food using flame atomic absorption spectrometry. The preconcentration system is based on the sorption of cadmium in a minicolumn packed with Amberlite XAD-2 resin functionalized with 3,4-dihydroxybenzoic acid (DHB). The optimized variables were pH and sampling flow rate and the optimum conditions found for these variables were, respectively 8.7 and 8.8 mL min-1. The developed system showed a preconcentration factor of 15.3, detection limit of 0.49 µg L-1, quantification limit of 1.65 µg L-1 and precision expressed as relative standard deviation (% RSD, n=10) of 5.9. The accuracy of the method was checked by analysis of estuary sediment certified reference material (NIST 1646-1). The cadmium concentrations found in sediment samples ranged from 1.73 and 1.90 µg g-1. In cigarette samples the results were 0.085 and 0.193 µg g-1, and in food samples (coriander and lettuce) the concentrations found of this metal were, respectively, 0.33 and 0.12 µg g-1.
Assuntos
Algoritmos , Cádmio/análise , Análise de Alimentos/métodos , Produtos do Tabaco/análise , Sedimentos Geológicos/química , Poliestirenos , Espectrofotometria Atômica/métodosRESUMO
BACKGROUND: Peri-implantitis is a chronic inflammation, resulting in loss of supporting bone around implants. Chronic periodontitis is a risk indicator for implant failure. Both diseases have a common etiology regarding inflammatory destructive response. BRINP3 gene is associated with aggressive periodontitis. However, is still unclear if chronic periodontitis and peri-implantitis have the same genetic background. The aim of this work was to investigate the association between BRINP3 genetic variation (rs1342913 and rs1935881) and expression and susceptibility to both diseases. METHODS: Periodontal and peri-implant examinations were performed in 215 subjects, divided into: healthy (without chronic periodontitis and peri-implantitis, n = 93); diseased (with chronic periodontitis and peri-implantitis, n = 52); chronic periodontitis only (n = 36), and peri-implantitis only (n = 34). A replication sample of 92 subjects who lost implants and 185 subjects successfully treated with implants were tested. DNA was extracted from buccal cells. Two genetic markers of BRINP3 (rs1342913 and rs1935881) were genotyped using TaqMan chemistry. Chi-square (p < 0.05) compared genotype and allele frequency between groups. A subset of subjects (n = 31) had gingival biopsies harvested. The BRINP3 mRNA levels were studied by CT method (2(ΔΔCT)). Mann-Whitney test correlated the levels of BRINP3 in each group (p < 0.05). RESULTS: Statistically significant association between BRINP3 rs1342913 and peri-implantitis was found in both studied groups (p = 0.04). The levels of BRINP3 mRNA were significantly higher in diseased subjects compared to healthy individuals (p = 0.01). CONCLUSION: This study provides evidence that the BRINP3 polymorphic variant rs1342913 and low level of BRINP3 expression are associated with peri-implantitis, independently from the presence of chronic periodontitis.
Assuntos
Periodontite Crônica/genética , Proteínas de Ligação a DNA/genética , Peri-Implantite/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Estudos Transversais , Implantes Dentários , Índice de Placa Dentária , Planejamento de Prótese Dentária , Feminino , Regulação da Expressão Gênica/genética , Frequência do Gene/genética , Marcadores Genéticos/genética , Predisposição Genética para Doença/genética , Variação Genética/genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Osseointegração/fisiologia , Índice Periodontal , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
BACKGROUND AND AIMS: Measurement of saliva urea nitrogen (SUN) may be valuable in the screening of kidney failure. Here we evaluate the diagnostic performance of SUN dipsticks in patients with acute kidney injury (AKI). MATERIAL AND METHODS: We measured SUN and blood urea nitrogen (BUN) in hospitalized patients diagnosed with AKI based on Acute Kidney Injury Network (AKIN)-criteria. After collection, saliva was transferred to a colorimetric SUN dipstick. We then compared the resultant test-pad color to six standardized color fields indicating SUN of 5 - 14 (#1), 15 - 24 (#2), 25 - 34 (#3), 35 - 54 (#4), 55 - 74 (#5), and ≥ 75 (#6) mg/dL, respectively. We assessed the performance of SUN and BUN to discriminate AKIN 3 from earlier stages by the area under receiver operating characteristic curves (AUC ROC). RESULTS: We enrolled 44 patients (59.5 ± 18 years, 58% female; pre-renal AKI: 67%; renal 24%; post-renal 9%) in AKIN stages 1 (59%), 2 (16%), and 3 (25%). SUN and BUN levels were correlated (Spearman rank Rs = 0.69; p < 0.001, n = 44) with the highest correlation in AKIN 1 (Rs = 0.63, p = 0.001, n = 26). SUN allowed a significant discrimination of AKIN 3 from earlier stages (AUC ROC 0.91; 95% CI 0.80 - 1.0), which was comparable to the diagnostic performance of BUN (AUC ROC 0.90; 95% CI 0.78 - 1.0). CONCLUSIONS: SUN dipsticks allow the discrimination of AKIN 3 from earlier AKI stages. This low-technology approach may aid the screening of severe AKI in areas where laboratory resources are scarce.
Assuntos
Injúria Renal Aguda/diagnóstico , Nitrogênio/análise , Testes Imediatos , Fitas Reagentes , Saliva/química , Ureia/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Nitrogênio da Ureia Sanguínea , Colorimetria/métodos , Colorimetria/estatística & dados numéricos , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Imediatos/estatística & dados numéricos , Valor Preditivo dos Testes , Curva ROC , Sensibilidade e EspecificidadeRESUMO
STATEMENT OF PROBLEM: Information regarding the differences in translucency among new ceramic systems is lacking. PURPOSE: The purpose of this study was to compare the relative translucency of the different types of ceramic systems indicated for porcelain veneers and to evaluate the effect of shade and thickness on translucency. MATERIAL AND METHODS: Disk specimens 13 mm in diameter and 0.7-mm thick were fabricated for the following 9 materials (n=5): VITA VM9, IPS Empress Esthetic, VITA PM9, Vitablocks Mark II, Kavo Everest G-Blank, IPS Empress CAD, IPS e.max CAD, IPS e.maxPress, and Lava Zirconia. VITA VM9 served as the positive control and Lava as the negative control. The disks were fabricated with the shade that corresponds to A1. For IPS e.maxPress, additional disks were made with different shades (BL2, BL4, A1, B1, O1, O2, V1, V2, V3), thickness (0.3 mm), and translucencies (high translucency, low translucency). Color coordinates (CIE L∗ a∗ b∗) were measured with a tristimulus colorimeter. The translucency parameter was calculated from the color difference of the material on a black versus a white background. One-way ANOVA, the post hoc Tukey honestly significant difference, and the Ryan-Einot-Gabriel-Welsch multiple range tests were used to analyze the data (α=.05). RESULTS: Statistically significant differences in the translucency parameter were found among porcelains (P<.001) according to the following rank: VM9>PM9, Empress Esthetic>Empress CAD>Mark II, Everest, e.max CAD>e.max Press>Lava. Significant differences also were noted when different shades and thickness were compared (P<.001). CONCLUSIONS: Different ceramic systems designed for porcelain veneers present varying degrees of translucency. The thickness and shade of lithium disilicate ceramic affect its translucency. Shade affects translucency parameter less than thickness.
Assuntos
Cerâmica/química , Materiais Dentários/química , Porcelana Dentária/química , Facetas Dentárias , Silicatos de Alumínio/química , Cor , Colorimetria/instrumentação , Humanos , Luz , Teste de Materiais , Compostos de Potássio/química , Pigmentação em Prótese , Propriedades de SuperfícieRESUMO
The advent of polymer-based dielectrics marked a significant breakthrough in dielectric materials. However, despite their many advantages, they pose serious environmental threats. Therefore, in recent years, there has been growing interest in bio-based polymers as a sustainable alternative to traditional petroleum-based polymers. Their renewable nature and reduced environmental impact can fulfil the rising demand for eco-friendly substitutes. Beyond their ecological benefits, bio-based polymers also possess distinctive electrical properties that make them extremely attractive in a variety of applications. Considering these, herein, we present recent advancements in bio-based dielectric polymers and nanocomposites. First, the fundamental concepts of dielectric and polymer-based dielectric materials are covered. Then, we will delve into the discussion of recent advancements in the dielectric properties and thermal stability of bio-based polymers, including polylactic acid, polyhydroxyalkanoates, polybutylene succinate, starch, cellulose, chitosan, chitins, and alginates, and their nanocomposites. Other novel bio-based dielectric polymers and their distinct dielectric characteristics have also been pointed out. In an additional section, the piezoelectric properties of these polymers and their recent biomedical applications have been highlighted and discussed thoroughly. In conclusion, this paper thoroughly discusses the recent advances in bio-based dielectric polymers and their potential to revolutionize the biomedical industry while cultivating a more sustainable and greener future.
Assuntos
Polímeros , Polímeros/química , Materiais Biocompatíveis/química , Humanos , Nanocompostos/químicaRESUMO
OBJECTIVE AND DESIGN: Among the options for treatment of diseases affecting the respiratory system, especially asthma, drug delivering systems for intranasal application represent an important therapeutic approach at the site of inflammation. The present study aimed to evaluate the therapeutic effect of biodegradable microparticles formed by poly lactic-co-glycolic acid (PLGA) containing encapsulated pomegranate extract on a murine model of asthma. MATERIAL: The extract was acquired from the leaves of P. granatum and characterized qualitatively by HPLC. A w/o/w emulsion solvent extraction-evaporation method was chosen to prepare the microparticles containing pomegranate encapsulated extract (MP). TREATMENT: OVA-sensitized BALB/c mice were used as asthma model and treated with dexamethasone and P. granatum extract in solution form or encapsulated into microparticles. RESULTS: MP were able to inhibit leukocytes' recruitment to bronchoalveolar fluid, especially, eosinophils, decreasing cytokines (IL-1ß and IL-5) and protein levels in the lungs. CONCLUSIONS: This approach can be used as an alternative/supplementary therapy based on the biological effects of P. granatum for managing inflammatory processes, especially those with pulmonary complications.
Assuntos
Anti-Inflamatórios/administração & dosagem , Asma/tratamento farmacológico , Portadores de Fármacos/administração & dosagem , Lythraceae , Extratos Vegetais/administração & dosagem , Animais , Anti-Inflamatórios/química , Asma/imunologia , Asma/patologia , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Citocinas/imunologia , Modelos Animais de Doenças , Portadores de Fármacos/química , Feminino , Ácido Láctico/química , Leucócitos/efeitos dos fármacos , Leucócitos/imunologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Fitoterapia , Extratos Vegetais/química , Folhas de Planta , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido PoliglicólicoRESUMO
PROBLEM: Polishing composite resin restorations may lead to marginal defects and gap formation. PURPOSE: To assess the effect of polishing direction on the marginal adaptation of composite resin restorations using two composite resins and two polishing systems. MATERIALS AND METHODS: Forty extracted human molars were sectioned along their mesio-distal axis. Buccal and lingual enamel was flattened and a triangular preparation, 0.87-mm deep and 3-mm wide, representing two 60° bevels, was performed. Specimens were randomly assigned to eight groups (N = 20) and restored with two composite resins: a nanofilled (Filtek Supreme Ultra, 3M ESPE, St. Paul, MN, USA) or a microhybrid (Point 4, Kerr, Orange, CA, USA) and finished with two polishing techniques: polishing discs (Sof-Lex XT, 3M ESPE) or rubber polishers (HiLuster Plus, Kerr, Bioggio, Switzerland). On each specimen, both margins were polished with the same technique, one margin from composite resin to tooth and the other from tooth to composite resin. Replicas were made for field emission scanning electron microscope observation (200×) and quantitative margin analysis was performed based on four criteria. Data were analyzed with a paired-sample t-test, a two-sample t-test, and one-way analysis of variance or their nonparametric analog. RESULTS: Significant differences were found in most groups between polishing directions with better marginal adaptation from composite resin to tooth than from tooth to composite resin. Differences between composite resins and polishing techniques seemed to be dependent on certain combinations of composite resin, polishing technique, and polishing direction. CONCLUSION: Polishing from composite resin to tooth leads to better marginal adaptation than polishing from tooth to composite resin. CLINICAL SIGNIFICANCE: The results obtained from this in vitro study suggest that polishing direction influences the marginal adaptation of composite resins and that polishing from composite resin to tooth structure should be clinically performed whenever possible on accessible margins to preserve marginal integrity and esthetics.
Assuntos
Resinas Compostas/química , Adaptação Marginal Dentária , Materiais Dentários/química , Polimento Dentário/métodos , Restauração Dentária Permanente , HumanosRESUMO
STATEMENT OF PROBLEM: Different parameters are used in the literature to describe translucency, making it difficult for clinicians to find clear information on ceramic translucency and compare studies. PURPOSE: The purpose of this study was to assess the correlation between the contrast ratio (CR) and translucency parameter (TP) when the translucency of different types of ceramic systems is compared. MATERIAL AND METHODS: Disks 13 mm in diameter and 0.7 mm thick were fabricated for the following materials (n=5): VITA VM9, VITA PM9, IPS Empress CAD, IPS e.max CAD, IPS e.maxPress, and Lava Zirconia. VITA VM9 served as positive control, while Lava Zirconia served as negative control. The luminous reflectance (Y) and color coordinates (CIE L* a* b*) of the specimens were measured with a tristimulus colorimeter. The CR (CR=Yb/Yw) was calculated from the reflectance of the light of the material on a black backing (Yb) to the reflectance on a white backing (Yw). The TP (TP=[(Lb*Lw*)(2+)(ab*-aw*)(2+)(bb*-bw*)(2) ](1/2)) was calculated from the color difference of the material on a black versus a white background. One-way ANOVA based on ranked data and the Pearson and Spearman rank correlation tests were used to analyze the data (α=.05). RESULTS: A significant correlation between CR and TP was found when all specimens were included (P<.001). The coefficient of -0.99 indicated a strong decreasing relationship between the 2 variables. CONCLUSIONS: Either CR or TP can be used to evaluate the relative translucency of ceramic systems.
Assuntos
Cerâmica/química , Porcelana Dentária/química , Facetas Dentárias , Silicatos de Alumínio/química , Cor , Colorimetria/instrumentação , Desenho Assistido por Computador , Materiais Dentários/química , Polimento Dentário/métodos , Humanos , Luz , Teste de Materiais , Compostos de Potássio/química , Pigmentação em Prótese , Propriedades de Superfície , Zircônio/químicaRESUMO
In recent years, domestic laundry has been recognized as a relevant source of microfiber (MF) pollution to aquatic environments. Nevertheless, the MF emissions from industrial washing processes in real world scenarios have not been quantified. The aim of this study was to quantify the MF emissions from 3 industrial washing processes (rinse wash, acid wash and enzymatic wash) commonly employed in the manufacturing process of blue jeans. The blue jeans were characterized by ATR-FT-IR, SEM and TGA to study the morphology, the polymer chemical identity and the proportion of synthetic and natural fibers, respectively. The MF emissions were quantified as the MF mass and number emitted per washed jean. All the industrial washing processes released a majority of synthetic MF. The enzymatic wash produced the highest amount of MF, with 1423 MF per gram of fabric (MF/g) equivalent to 381.7 MF grams per gram of fabric (MF g/g), followed by the acid wash with 253 MF/g equivalent to 142.7 MF g/g and lastly the rinse wash with 133 MF/g equivalent to 62.3 MF g/g. Statistically significant differences between the MF sizes for all washing processes were found when evaluating the emissions by MF/g, however, the previous trend was not found for MF g/g. Moreover, the total MF emissions of an industrial washing process of a pair of blue jeans during its manufacture process are up to 10.95 times higher than the reported domestic washing estimates performed by the consumer available in the published literature. We demonstrate that studying industrial washing procedures of textile garments will improve the accuracy of the current estimates of MF emissions available in published reports, which will ultimately aid in the development of regulations for MF emissions at an industrial level.
Assuntos
Lavanderia , Plásticos , Microplásticos , Espectroscopia de Infravermelho com Transformada de Fourier , Lavanderia/métodos , TêxteisRESUMO
We report the first occurrence in South America of spinosaurid specimens belonging to the clade Baryonychinae. The material comprises three tooth crowns recovered from the Lower Cretaceous (Berriasian-Valanginian) of the Feliz Deserto Formation, State of Sergipe, northeast Brazil. The three specimens have the typical conidont condition, displaying a fluted morphology, veined enamel texture and carinae extending to the cervix region, conditions similar to those shared among spinosaurid theropods. Furthermore, a notable feature is the presence of a serrated carinae composed of 6-7 diminutive denticles per millimetre, a key feature shared by baryonychine spinosaurids. Phylogenetic and multivariate analyses performed on dentition-based and crown-based datasets of theropod taxa confirm the relationship of the three tooth crowns described here with the well-supported spinosaurid clade. Our results retrieve the taxa which comprise the "classically" baryonychine clade as individual branches within a polytomy which includes the three tooth crowns and a subclade of spinosaurines (Spinosaurus + Angaturama/Irritator). Additionally, the discriminant and cluster analyses suggest that the materials are more similar to Suchomimus than to Baryonyx morphometrically, but clearly bearing similarities with baryonychines (sharing a similar morphospace). These new findings paleogeographically expand the occurrence of this clade to western Gondwana, and comprise one of the oldest spinosaurid records worldwide, which brings implications on hypotheses for the emergence and evolution of the clade. Furthermore, these new records indicate the presence of more than one spinosaurid taxon in the Lower Cretaceous deltaic paleoenvironment of the Feliz Deserto Formation.
Assuntos
Dinossauros , Fósseis , Coroa do Dente , Animais , Dinossauros/anatomia & histologia , Dinossauros/classificação , Filogenia , Coroa do Dente/anatomia & histologia , BrasilRESUMO
This study evaluated the effect of five methods of solvent volatilization on the degree of conversion (DC) of nine one-bottle adhesive systems using Fourier transform infrared/attenuated total reflectance (FTIR/ATR) analysis. Nine adhesives were tested: Adper Single Bond 2 (SB), Adper Easy One (EO), One Up Bond F Plus (OUP), One Coat Bond SL (OC), XP Bond (XP), Ambar (AM), Natural Bond (NB), GO, and Stae. The adhesive systems were applied to a zinc-selenide pellet and 1) cured without solvent volatilization, 2) left undisturbed for 10 seconds before curing, 3) left undisturbed for 60 seconds before curing, 4) air-dried with an air stream for 10 seconds before curing, and 5) air-dried with an air stream for 60 seconds before curing. FTIR/ATR spectra were obtained, and the DC was calculated by comparing the aliphatic bonds/reference peaks before and after light activation for 10 seconds (FlashLite 1401). The DC means of each material were analyzed by one-way analysis of variance and post hoc Tukey test (p<0.05). The DC of GO and Stae adhesive systems was not affected by the five evaporation conditions. Air-drying for 60 seconds before curing yielded the highest DC for SB, EO, and OC. Extended solvent volatilization time (60 seconds) either with or without air-drying before curing provided the highest DC for AM, NB, XP, and OUP. Thus, the monomer conversion of adhesive systems was material dependent. In general, the 60-second passive or active air-drying modes to volatilize solvents before curing enhanced the degree of conversion for the one-bottle simplified adhesive systems.
Assuntos
Cura Luminosa de Adesivos Dentários , Cimentos de Resina/química , Acetona , Ar , Etanol , Dureza , Polimerização , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier , Volatilização , ÁguaRESUMO
Secondary lymphedema of the upper limb is a complication which can be found in patients who have undergone surgical breast cancer treatment with an axillary dissection. Lymphedema following breast cancer treatment remains a long-term disabling complication which cannot be treated in a decisive and radical manner. The objective of the treatment is to limit complications, to try to preserve the remaining lymphatic system and to develop new anastomosis. It consists of a specific decongestive physiotherapy, which may include a specific lymphatic drainage and skin mobilization, reducing bandages including Mobiderm (Thuasne), and sub-bandage muscular exercises. However variations in the therapy have been recorded by different teams. Our experience in treating lymphedema in Tunisia takes into consideration the epidemiological, climatic, cultural and socio-economic conditions of the country. The difference in our treatment compared to what is being advocated elsewhere essentially consists of the no muscular exercise while wearing a bandage. This is compensated for by daily domestic activities, by prolonging the first two phases of treatment (the intensive phase and the stabilization phase), and by the use of the hydro gel dressing Hydrosob (Hartmann) to prevent blisters induced by the pressure imposed by Mobiderm studs of the bandage on the skin, and also by the superimposition of two types of Mobiderm bandages (small and large blocks).