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1.
J Agric Food Chem ; 67(37): 10361-10372, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31487173

RESUMO

Alkyl di-/tri-/tetraoxyethyl ß-d-xylopyranosides as derivatives of alkyl xylosides are a class of non-ionic sugar-based surfactants. They were stereoselectively synthesized by the Helferich method. Their properties including hydrophilic-lipophilic balance number, water solubility, surface property, foam property, emulsifying property, and thermotropic liquid crystal property were mainly investigated. The results showed that their water solubility decreased with increasing the alkyl chain length and increasing the number of the oligooxyethyl fragment. The critical micelle concentration had a monotonous decreasing trend with increasing the alkyl chain length. Nonyl di-/tri-/tetraoxyethyl ß-d-xylopyranosides [-(OCH2CH2)m-, where m = 2, 3, and 4] exhibited the most excellent foaming ability and foam stability. In the n-octane/water system, dodecyl tetraoxyethyl ß-d-xylopyranosides and tetradecyl tetraoxyethyl ß-d-xylopyranosides had the strongest emulsion ability. In addition, some alkyl di-/tri-/tetraoxyethyl ß-d-xylopyranosides had thermotropic liquid crystal properties. Such sugar-based surfactants, alkyl di-/tri-/tetraoxyethyl ß-d-xylopyranosides, will be expected to develop for a variety of practical application.


Assuntos
Glicosídeos/química , Tensoativos/química , Glicosídeos/síntese química , Interações Hidrofóbicas e Hidrofílicas , Solubilidade , Propriedades de Superfície , Tensoativos/síntese química
2.
Top Curr Chem (Cham) ; 377(5): 25, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31529217

RESUMO

Metal-organic frameworks (MOFs) have gathered tremendous interest among researchers for their potential applications such as in storage and separation. While some progress has been made towards shaping of MOFs to realize industrial applications, the mechanical properties of MOFs remain more or less unexplored. Over the last decade, this area has witnessed a steady growth in terms of understanding the mechanical stability of MOFs and its consequence on their performance. In this review, the mechanical properties of the reported macroscopic shaped MOF structures (mainly granules, pellets, tablets, monoliths, and gels) are discussed. Conclusions are then drawn to determine which shapes and shaping techniques promise to meet industrial requirements on the basis of mechanical stability. Finally, future research directions are proposed to improve our understanding, and possibly enhance stability, by correlating the properties from microscopic single-crystalline level to the industrially relevant macroscopic polycrystalline scale.


Assuntos
Estruturas Metalorgânicas/química , Estrutura Molecular , Tamanho da Partícula , Porosidade , Propriedades de Superfície
3.
Pharm Res ; 36(11): 154, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31482205

RESUMO

PURPOSE: Conjugation of nanocarriers with antibodies that bind to specific membrane receptors that are overexpressed in cancer cells enables targeted delivery. In the present study, we developed and synthesised two PAMAM dendrimer-trastuzumab conjugates that carried docetaxel or paclitaxel, specifically targeted to cells which overexpressed HER-2. METHODS: The 1H NMR, 13C NMR, FTIR and RP-HPLC were used to analyse the characteristics of the products and assess their purity. The toxicity of PAMAM-trastuzumab, PAMAM-doc-trastuzumab and PAMAM-ptx-trastuzumab conjugates was determined using MTT assay and compared with free trastuzumab, docetaxel and paclitaxel toward HER-2-positive (SKBR-3) and negative (MCF-7) human breast cancer cell lines. The cellular uptake and internal localisation were studied using flow cytometry and confocal microscopy, respectively. RESULTS: The PAMAM-drug-trastuzumab conjugates in particular showed extremely high toxicity toward the HER-2-positive SKBR-3 cells and very low toxicity towards to HER-2-negative MCF-7 cells. As expected, the HER-2-positive SKBR-3 cell line accumulated trastuzumab from both conjugates rapidly; but surprisingly, although a large amount of PAMAM-ptx-trastuzumab conjugate was observed in the HER-2-negative MCF-7 cells. Confocal microscopy confirmed the intracellular localisation of analysed compounds. The key result of fluorescent imaging was the identification of strong selective binding of the PAMAM-doc-trastuzumab conjugate with HER-2-positive SKBR-3 cells only. CONCLUSIONS: Our results confirm the high selectivity of PAMAM-doc-trastuzumab and PAMAM-ptx-trastuzumab conjugates for HER-2-positive cells, and demonstrate the utility of trastuzumab as a targeting agent. Therefore, the analysed conjugates present an promising approach for the improvement of efficacy of targeted delivery of anticancer drugs such as docetaxel or paclitaxel.


Assuntos
Antineoplásicos/química , Neoplasias da Mama/tratamento farmacológico , Dendrímeros/química , Docetaxel/química , Paclitaxel/química , Receptor ErbB-2/metabolismo , Trastuzumab/química , Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Docetaxel/farmacologia , Interações de Medicamentos , Liberação Controlada de Fármacos , Corantes Fluorescentes/química , Humanos , Paclitaxel/farmacologia , Propriedades de Superfície , Trastuzumab/farmacologia , Resultado do Tratamento
4.
Braz Oral Res ; 33: e041, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508723

RESUMO

The objective of this study was to evaluate the effect of the hydrofluoridric acid (HF) concentration and time of acid conditioning on bond strength of three glass ceramics to a resin cement. Thus, fifty blocks (10 mm x 5 mm x 2 mm) of each ceramic (LDCAD: IPS e.max CAD; LCAD: IPS Empress CAD and LDHP: IPS e.max Press) were made and embedded in acrylic resin. The surfaces were polished with sandpaper (#600, 800, 1000, and 1200 grits) and blocks were randomly divided into 15 groups (n = 10) according to the following factors: Concentration of HF (10% and 5%), conditioning time (20 s and 60 s) and ceramic (LDCAD, LDHP, and L). After conditioning, silane (Prosil / FGM) was applied and after 2 min, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block using a Teflon strip as matrix and light cured for 40 s (1,200 mW/cm2). Then, the samples were thermocycled (10,000 cycles, 5/55°C, 30s) and submitted to the shear bond test (50 KgF, 0.5 mm/min). The data (MPa) were analyzed with 3-way ANOVA and Tukey's test (5%). Failure analysis was performed using a stereomicroscope (20x) and a scanning electron microscope (SEM). ANOVA revealed that the "concentration" factor (p = 0.01) and the interaction "acid concentration X ceramic" (p = 0.009) had a significant effect, however, the "ceramic" (p = 0.897) and "conditioning time" (p = 0.260) factors did not influence the results. The LDHP10%60s (10.98 MPa)aA* group presented significantly higher bond strength than LDHP10%20s (6.57 MPa)bA, LCAD5%20s (6,90 ±3,5)aB and LDHP5%60s (5.66 ± 2,9MPa)aA* groups (Tukey). Failure analysis revealed that 100% of specimens had mixed failure. In conclusion, etching with 5% HF for 20 seconds is recommended for lithium disilicate and leucite-reinforced CAD/CAM ceramics. However, for pressed lithium disilicate ceramic, 10% HF for 60 s showed significantly higher bond strength to resin cement.


Assuntos
Ataque Ácido Dentário , Cerâmica/química , Colagem Dentária/métodos , Ácido Fluorídrico/administração & dosagem , Porcelana Dentária/química , Análise do Estresse Dentário , Ácido Fluorídrico/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Cimentos de Resina/química , Resistência ao Cisalhamento , Propriedades de Superfície , Fatores de Tempo
5.
Braz Oral Res ; 33: e040, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508724

RESUMO

The study characterizes dental implant surfaces treated with phosphoric acid to assess the effects of acid treatment on blood cells and correlate them with cytokine levels. The implant surfaces examined were divided into untreated metal surface (US; n = 50), metal surface treated with phosphoric acid (ATS; n = 50) and cement surface (CS; n = 50) groups. The samples were characterized by scanning electron microscopy (SEM) and rheometry. The implants were incubated with human blood mononuclear cells for 24 h, with surface rinsing in the ATS treatment. Cell viability was determined by colorimetric methods and cytokines in the culture supernatant were quantified using flow cytometry. In the ATS group, the surface porosity and contact surface were increased and plaques were observed on the surface. The blood flow and viscosity curves were similar among the treatments, and the high cell viability rates indicate the biocompatibility of the materials used. An increase in the levels of IL-2, IL-4, IL-6, IL-10 and TNF-α was observed in the ATS and CS groups. There were positive correlations between IL-10 and IL-2 levels and between IL-10 and IL-4 levels in the culture supernatant of the ATS group. The results suggest that implant surface treatment with phosphoric acid activates the production of inflammatory cytokines. The increased cytokine levels can modulate the immune response, thereby improving biofunctional processes and promoting the success of dental implants.


Assuntos
Citocinas/análise , Implantes Dentários , Materiais Dentários/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Ácidos Fosfóricos/farmacologia , Anti-Inflamatórios , Sobrevivência Celular , Citocinas/metabolismo , Cimentos Dentários , Humanos , Interleucina-10/análise , Interleucina-10/metabolismo , Microscopia Eletrônica de Varredura , Reologia , Propriedades de Superfície
6.
Braz Oral Res ; 33: e037, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508726

RESUMO

Iontophoresis is a noninvasive technique, based on the application of a constant low-intensity electric current to facilitate the release of a variety of drugs, whether ionized or not, through biological membranes. The objective of this research was to evaluate the effect of iontophoresis using different electric current intensities on the uptake of fluoride in dental enamel with artificial caries lesions. In this in vitro operator-blind experiment, bovine enamel blocks (n = 10/group) with caries-like lesions and predetermined surface hardness were randomized into 6 groups: placebo gel without fluoride applied with a current of 0.8 mA (negative control), 2% NaF gel without application of any current, and 2% NaF gel applied with currents of 0.1, 0.2, 0.4 and 0.8 mA. Cathodic iontophoresis was applied for 4 min. The concentration of loosely bound fluoride (calcium fluoride) and firmly bound fluoride (fluorapatite) was determined. The results were analyzed by the nonparametric Kruskal-Wallis and Dunn tests. Iontophoresis at 0.8 mA, combined with the application of fluoridated gel (2% NaF), increased fluoride uptake in enamel with caries-like lesions, as either calcium fluoride or fluorapatite.


Assuntos
Cariostáticos/farmacologia , Cárie Dentária , Esmalte Dentário/efeitos dos fármacos , Fluoretos/farmacologia , Iontoforese/métodos , Animais , Apatitas/análise , Fluoreto de Cálcio/análise , Bovinos , Modelos Animais de Doenças , Eletricidade , Dureza/efeitos dos fármacos , Distribuição Aleatória , Propriedades de Superfície/efeitos dos fármacos , Resultado do Tratamento
7.
J Appl Oral Sci ; 27: e20180262, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508789

RESUMO

The incorporation of antimicrobials in the composites as an attempt to reduce bacterial adhesion without jeopardizing mechanical properties is a challenge for Dentistry. OBJECTIVE To evaluate the bacterial adhesion and physical properties of a composite containing the methacrylate triclosan- derivative monomer (TM). METHODOLOGY TM was synthesized and added to an experimental composite. Samples were divided into two groups: Control and TM (13.4 wt%). Antibacterial Activity: Three specimens of each material were prepared and placed on bacterial suspensions of Streptococcus mutans for 1, 5 and 10 days. After these periods the counting of the colonies (log10) was performed. Assays was performed in triplicate. Physical Properties: Three-body Abrasion (TBA): Ten specimens of each material were prepared and stored at 37°C/24 h. The surface roughness (Ra) and hardness (KHN) were analyzed. Next, the specimens were submitted to abrasive wear (30,000 cycles) and re-evaluated for Ra and KHN; Sorption/solubility (SS): cylindrical specimens (n=10) were prepared and weighted. The specimens were immersed in deionized water for 7 days at 37°C and then their weight was verified again. SS were calculated using accepted formulas; Diametral tensile strength (DTS): specimens (n=10) underwent test performed in an Instron universal testing machine at a crosshead speed of 1 mm/min. Data were submitted to appropriate statistical tests according to data distribution and assay (p<0.05). RESULTS Bacterial Adhesion: TM showed a significant reduction on biofilm accumulation in the evaluated periods: 1 day (1.537±0.146); 5 days (2.183±0.138) and 10 days (4.469±0.155) when compared with Control: 1 day (4.954±0.249); 5 days (5.498±0.257) and 10 days (6.306±0.287). Physical Properties: For TBA, SS and DTS no significant difference was found between groups Control and TM. The incorporation of methacrylate triclosan-based monomer in the experimental composite reduce bacterial adhesion of S. mutans and did not affect important polymer properties.


Assuntos
Antibacterianos/química , Resinas Compostas/química , Metacrilatos/química , Triclosan/química , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Contagem de Colônia Microbiana , Resinas Compostas/farmacologia , Testes de Dureza , Teste de Materiais , Metacrilatos/farmacologia , Valores de Referência , Reprodutibilidade dos Testes , Solubilidade , Streptococcus mutans/efeitos dos fármacos , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Escovação Dentária , Triclosan/farmacologia
8.
J Appl Oral Sci ; 27: e20180556, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508791

RESUMO

OBJECTIVE: To evaluate the effect of ultrasonic and sonic activation on physicochemical properties of AH Plus, MTA Fillapex, ADSeal, GuttaFlow Bioseal, and GuttaFlow 2 sealers. METHODOLOGY: Three experimental groups were formed: no activation (NA), ultrasonic activation (UA), and sonic activation (SA). The sealers were manipulated according to the manufacturers' instructions. A 3-mL syringe was adapted to receive 1 mL of sealer. Activation was performed with a 20/.01 ultrasonic insert (20 s/1W) in the UA group. A size 35.04 sonic tip was used (20 s/10,000 cycles/min-1) in the SA group. The molds for physicochemical analysis were filled and evaluated according to ANSI/ADA specification no. 57: setting time (ST), flow (FL), dimensional change (DC), solubility (SB), and radiopacity (RD). Statistical analysis was performed by Kruskal-Wallis, one-way ANOVA, and Tukey's tests (P<0.05). RESULTS: Regarding ST, only AH Plus and GuttaFlow 2 in the NA group met the ANSI/ADA standards. All FL values were greater than 20 mm in diameter, as determined by ANSI/ADA. The tested sealers and protocols did not comply with the ANSI/ADA standards for DC. As for SB, only MTA Fillapex, regardless of the activation protocol, did not follow the ANSI/ADA standards. All of the investigated sealers, regardless of the activation protocol, presented radiographic density higher than 3 mm Al, as proposed by ANSI/ADA. CONCLUSIONS: UA and SA promoted changes in the physicochemical properties of the evaluated root canal sealers, mainly in ST and F. Thus, it is important to evaluate the physicochemical properties of endodontic sealers associated with activation techniques prior to clinical application in order to determine whether the properties follow the parameters set by ANSI/ADA, ensuring safety and quality of root canal filling.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Dimetilpolisiloxanos/química , Resinas Epóxi/química , Guta-Percha/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Ondas Ultrassônicas , Análise de Variância , Combinação de Medicamentos , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Solubilidade , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de Tempo
9.
J Appl Oral Sci ; 27: e20180593, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508792

RESUMO

There is growing evidence that C. albicans is associated with dental caries, but its role on caries development needs to be better clarified. Label="OBJECTIVE">To evaluate at the hard tissue level the effect of C. albicans on the cariogenic potential of S. mutans biofilms focusing on the mineral profile of induced carious lesions. This study also aimed to evaluate the effect of C. albicans on the acidogenic potential of S. mutans biofilms. METHODOLOGY Dual-species (CA+SM) and single-species biofilms (CA or SM) were grown on the surface of enamel slabs in the presence of glucose/sucrose supplemented culture medium for 24, 48 and 72 hours. Demineralization was evaluated through percentage of surface microhardness change (%SMC) and transversal microradiography analysis (ILM and LD) and pH of the spent medium was recorded daily. Data were analyzed by two-way ANOVA followed by Bonferroni correction. RESULTS%SMC was statistically different among the biofilms at each time point being the highest for SM biofilms and the lowest for CA biofilms which also differed from CA+SM biofilms [SM (24 h: 47.0±7.3; 48 h: 66.3±8.3; 72 h: 75.4±3.9); CA (24 h: 7.3±3.3; 48 h: 7.1±6.4; 72 h: 6.6±3.6); CA+SM (24 h: 35.9±7.39.1; 48 h: 47.2±9.5; 72 h: 47.6±9.5)]. pH of spent medium was statistically lower for SM biofilms compared to the other biofilms at each time point and remained constant over time while pH values increased from 24 to 72 h for both CA and CA+SM biofilms [SM (24 h: 4.4±0.1; 48 h: 4.4±0.1; 72 h: 4.5±0.1); CA (24 h: 6.9±0.3; 48 h: 7.2±0.2; 72 h: 7.5±0.2); CA+MS (24 h: 4.7±0.2; 48 h: 5.1±0.1; 72 h: 6.1±0.6)]. IML and LD for SM biofilms increased over time while no difference was observed from 24 to 72 h for the other biofilms. CONCLUSIONS The present data suggest that C. albicans has low enamel demineralization potential and the presence of C. albicans can reduce both the cariogenic and acidogenic potentials of S. mutans biofilms.


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Esmalte Dentário/microbiologia , Streptococcus mutans/metabolismo , Desmineralização do Dente/microbiologia , Ácidos/metabolismo , Animais , Bovinos , Contagem de Colônia Microbiana , Esmalte Dentário/química , Testes de Dureza , Concentração de Íons de Hidrogênio , Microrradiografia/métodos , Valores de Referência , Propriedades de Superfície , Fatores de Tempo
10.
Braz Oral Res ; 33: e053, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31531561

RESUMO

Self-adhesive resin cements (RCs) activate matrix metalloproteinase (MMP) and cathepsin-related collagen degradation, and gallic acid (GA) inhibits the activity of both MMPs and cysteine cathepsins. The purpose of this study was to evaluate the setting time, biaxial flexural strength, and Vickers hardness of self-adhesive RCs after the addition of two different concentrations of GA. RelyX U200 (3M ESPE) and Panavia SA (Kuraray) were modified with 0.5 and 1 wt% GA. The setting time of five samples in each RC group was assessed using a thermocouple apparatus as described in the ISO 4049 test. Biaxial flexure strength was measured using a universal testing machine until failure. Vickers hardness was measured with three randomized indentations on the surface of each resin disc. RCs without GA were used as control. Data were analyzed using a one-way analysis of variance and Tukey's HSD test (α = 0.05). The setting times ranged from 2.4 to 4.6 min for RelyX and from 4.9 to 6.0 min for Panavia. The biaxial flexure strength ranged from 76.5 to 109.7 MPa for RelyX and from 73.3 to 108.2 MPa for Panavia. Vickers hardness values ranged from 41.6 to 58.6 for RelyX and 27.2 to 33.6 for Panavia. The addition of 0.5 and 1 wt% GA to improve durability of resin-dentin bonds had no adverse effects on setting time, whereas the biaxial flexure strength and Vickers hardness values for the tested materials were significantly reduced.


Assuntos
Ácido Gálico/química , Cimentos de Resina/química , Análise de Variância , Resistência à Flexão , Testes de Dureza , Teste de Materiais , Metaloproteinases da Matriz/química , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de Tempo
11.
Braz Oral Res ; 33: e0088, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31531566

RESUMO

The main of the study was quantify the effect of two ceramics with two underlying resin cements on apparent fluorescence levels. Buccal surfaces of two bovine incisors were ground flat producing one enamel and one dentin substrate. The veneers were fabricated (0.5 and 1.0 mm thickness) using two ceramics (IPSe.max Press and IPSe.max Zirpress, Ivoclar Vivadent). Veneers were cemented using either light-cured (Variolink II, Ivoclar Vivadent) or self-adhesive dual (Rely X U200, 3M ESPE) cement. The layered Control group materials had no cement application. Semi-quantitative fluorescence image analysis (Matlabs software, Matworks) involved processing the images as captured under each daylight (DL, Gretagmacbeth) and ultraviolet illuminants (UVA, Sylvania) within a neutral-gray lightbox (Macbeth Spectral Light). Statistical analysis of the quantitative fluorescence values was performed using two-way ANOVA and Tukey's test (p < 0.05). The e.max Zirpress on the dentin substrate produced greater fluorescence (p < 0.05) when subjected to UV illumination and more fluorescence (p < 0.05) than e.max Press in both cement groups. Light-cured cement produced higher (p < 0.05) fluorescence than the dual-cement with e.max Press on enamel under UV illumination. The fluorescence for e.max Press on the dentin substrate was greater (p < 0.05) than for e.max Zirpress using dual self-adhesive cement subjected to daylight illumination. Thus, it is possible to conclude that the combination of ceramic and cement produce definite, significant effects on the apparent fluorescence, vital quality for restorative dentistry.


Assuntos
Cerâmica/química , Facetas Dentárias , Imagem Óptica/métodos , Cimentos de Resina/química , Animais , Bovinos , Esmalte Dentário/química , Esmalte Dentário/efeitos dos fármacos , Dentina/química , Dentina/efeitos dos fármacos , Luz , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Propriedades de Superfície
12.
J Nanobiotechnology ; 17(1): 86, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387581

RESUMO

BACKGROUND: Controllable and multiple DNA release is critical in modern gene-based therapies. Current approaches require complex assistant molecules for combined release. To overcome the restrictions on the materials and environment, a novel and versatile DNA release method using a nano-electromechanical (NEMS) hypersonic resonator of gigahertz (GHz) frequency is developed. RESULTS: The micro-vortexes excited by ultra-high frequency acoustic wave can generate tunable shear stress at solid-liquid interface, thereby disrupting molecular interactions in immobilized multilayered polyelectrolyte thin films and releasing embedded DNA strands in a controlled fashion. Both finite element model analysis and experiment results verify the feasibility of this method. The release rate and released amount are confirmed to be well tuned. Owing to the different forces generated at different depth of the films, release of two types of DNA molecules with different velocities is achieved, which further explores its application in combined gene therapy. CONCLUSIONS: Our research confirmed that this novel platform based on a nano-electromechanical hypersonic resonator works well for controllable single and multi-DNA release. In addition, the unique features of this resonator such as miniaturization and batch manufacturing open its possibility to be developed into a high-throughput, implantable and site targeting DNA release and delivery system.


Assuntos
DNA/química , Nanoestruturas/química , Polieletrólitos/química , Acústica/instrumentação , Fenômenos Biofísicos , Desenho de Equipamento , Análise de Elementos Finitos , Técnicas de Transferência de Genes , Terapia Genética/métodos , Membranas Artificiais , Propriedades de Superfície
13.
Chem Pharm Bull (Tokyo) ; 67(8): 801-809, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31366829

RESUMO

Granules prepared by a continuous twin screw granulator (TSG) were analyzed by X-ray micro-computed tomography (X-ray µCT) and the relationships between porosity of granules and granule properties were investigated. A model formulation containing ibuprofen, lactose monohydrate, microcrystalline cellulose, and hydroxypropyl cellulose was used. The porosity of granules was measured by X-ray µCT and mercury porosimetry. The data sets obtained by both methods showed linear correlation despite different values, which were attributed to the resolution of X-ray µCT and a low-signal-to-noise ratio of the original cross-sectional images. The porosity of granules measured by X-ray µCT decreased from 11-14 to 6-7% as liquid-to-solid ratio (L/S) increased, while the standard deviation (S.D.) of the porosity of individual granules decreased from 4-5 to 2%. L/S affected the porosity of granules. By contrast, the effect of screw speed was not significant. Pressure transmission, G, which indicates the liquid dispersion in wet kneaded masses, increased as the porosity of granules and the S.D. decreased. The cross-sectional images showed that granules were densified as L/S increased. Based on these results, the effect of L/S on the porosity of granules can be explained by liquid dispersion and densification of the wet granules. The porosity of granules measured by X-ray µCT showed good linear correlation with friability and drug dissolution rate (R2 = 0.9107 and 0.8834, respectively). This study revealed that the drug dissolution rate was regulated by a disintegration step in which the porosity of granules plays an important role.


Assuntos
Parafusos Ósseos , Tecnologia Farmacêutica , Microtomografia por Raio-X , Tamanho da Partícula , Porosidade , Propriedades de Superfície , Raios X
14.
J Appl Oral Sci ; 27: e20180689, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31411264

RESUMO

OBJECTIVE: The aim of this study was to evaluate the root canal preparation and apical enlargement of molar root canals with rotary or reciprocating heat-treated nickel-titanium (NiTi) instruments, by using micro-computed tomography (micro-CT). METHODOLOGY: Mesial root canals (n=48) of mandibular molars, with a curvature between 20° and 40°, were prepared with ProDesign Logic (PDL) 25.01 and 25.06 in rotary motion, or ProDesign R (PDR) 25.06 in reciprocating motion (PDR). Apical enlargement was performed with PDL35.01 and PDL35.05 or PDR35.05. Scanning with 9 µm resolution was performed before and after preparation, and, after apical enlargement, by using micro-CT. The percentage of volume increase, debris and untouched root canal surface, transportation, centralization and preparation time were analyzed. ANOVA and Tukey or Kruskall-Wallis and Dunn statistical tests were conducted (α=.05). RESULTS: PDL promoted a higher apical percentage of volume increase, and lower percentage of debris and untouched root canal surface than PDR 25.06 preparation in entire canal and in all thirds (P<.05). Apical enlargement with PDL 35.05 and PDR 35.05 produced a higher percentage of volume increase in the apical region in relation to the initial preparation (P<.05). PDR 35.05 and PDL 35.05 showed similar results in relation to percentage of debris and untouched root canal surface in entire canal and in all thirds (P>.05). Centralization and transportation showed no difference (P>.05). PDR required less time to perform preparation and apical enlargement (P<.05). CONCLUSIONS: The apical enlargement 35.05 with CM heat-treatment instruments using reciprocating and rotary motion reduced the percentage of debris and untouched root canal surface, without causing deviations or procedural errors. The protocol of greater apical enlargement favors the cleaning of the root canals in both kinematics. Preparation by the reciprocating system was faster than by the rotary system.


Assuntos
Instrumentos Odontológicos , Cavidade Pulpar/diagnóstico por imagem , Níquel , Preparo de Canal Radicular/instrumentação , Titânio , Análise de Variância , Cavidade Pulpar/anatomia & histologia , Desenho de Equipamento , Temperatura Alta , Humanos , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície , Microtomografia por Raio-X
15.
J Chem Theory Comput ; 15(9): 5135-5143, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31390206

RESUMO

Predicting the assembly of multiple proteins into specific complexes is critical to understanding their biological function in an organism and thus the design of drugs to address their malfunction. Proteins are flexible molecules, which inherently pose a problem to any protein docking computational method, where even a simple rearrangement of the side chain and backbone atoms at the interface of binding partners complicates the successful determination of the correct docked pose. Herein, we present a means of representing protein surface, electrostatics, and local dynamics within a single volumetric descriptor. We show that our representations can be physically related to the surface-accessible solvent area and mass of the protein. We then demonstrate that the application of this representation into a protein-protein docking scenario bypasses the need to compensate for, and predict, specific side chain packing at the interface of binding partners. This representation is leveraged in our de novo protein docking software, JabberDock, which can accurately and robustly predict difficult target complexes with an average success rate of >54%, which is comparable to or greater than the currently available methods.


Assuntos
Simulação de Acoplamento Molecular , Proteínas/química , Eletricidade Estática , Termodinâmica , Ligação Proteica , Propriedades de Superfície
16.
J Chem Theory Comput ; 15(9): 5046-5057, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31390517

RESUMO

Halogenated BODIPY derivatives are emerging as important candidates for photodynamic therapy of cancer cells due to their high triplet quantum yield. We probed fundamental photophysical properties and interactions with biological environments of such photosensitizers. To this end, we employed static TD-DFT quantum chemical calculations as well as TD-DFT surface hopping molecular dynamics on potential energy surfaces resulting from the eigenstates of the total electronic Hamiltonian including the spin-orbit (SO) coupling. Matrix elements of an effective one-electron spin-orbit Hamiltonian between singlet and triplet configuration interaction singles (CIS) auxiliary wave functions are calculated using a new code capable of dealing with singlets and both restricted and unrestricted triplets built up from up to three different and independent sets of (singlet, alpha, and beta) molecular orbitals. The interaction with a biological environment was addressed by using classical molecular dynamics (MD) in a scheme that implicitly accounts for electronically excited states. For the surface hopping trajectories, an accelerated MD approach was used, in which the SO couplings are scaled up, to make the calculations computationally feasible, and the lifetimes are extrapolated back to unscaled SO couplings. The lifetime of the first excited singlet state estimated by semiclassical surface hopping simulations is 139 ± 75 ps. Classical MD demonstrates that halogenated BODIPY in the ground state, in contrast to the unsubstituted one, is stable in the headgroup region of minimalistic cell membrane models, and while in the triplet state, the molecule relocates to the membrane interior ready for further steps of photodynamic therapy.


Assuntos
Compostos de Boro/química , Simulação de Dinâmica Molecular , Fotoquimioterapia , Teoria da Densidade Funcional , Processos Fotoquímicos , Fármacos Fotossensibilizantes/química , Teoria Quântica , Propriedades de Superfície
17.
Am J Dent ; 32(4): 159-164, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31436934

RESUMO

PURPOSE: To compare the effect of thermal cycling and erosive challenge on color change, surface roughness, surface loss and biofilm deposition of three resin-based composites. METHODS: Three resin-based composites that reproduce the color of gingival tissues [two nanohybrid composites (A and B) and a giomer (C) ] were tested before and after distinct challenges [ thermal cycling (TC) and erosive challenge (EC) ] in regard to its color stability, surface roughness, surface loss and biofilm deposition. Surface roughness and surface loss specimens (n=10) were measured with an optical profilometer and, color stability (n=10) was measured with a spectrophotometer. Biofilm deposition (n=5) was measured after 3 and 24 hours by safranin staining. RESULTS: Two-way ANOVA test was performed to analyze color change, roughness and surface loss. A significant color change was detected for resin-based composites (P< 0.05) and its interaction with tested challenges (P< 0.05). The highest color variation was observed on the giomer after erosive challenge. Surface loss was not different between tested groups (P= 0.708). The roughness was significantly higher in specimens submitted to thermal cycling (P> 0.05). For biofilm quantification, after 3 and 24 hours, ANOVA (3-way) detected significance for the interaction of challenges and resin-based composites (P< 0.05 and P< 0.05, respectively). All resin-based composites presented color changes after challenges; higher roughness was observed after thermal cycling for all resin-based composites tested, without significant surface loss; and higher biofilm deposition was observed on the giomer samples when submitted to erosive challenge after 3 and 24 hours. CLINICAL SIGNIFICANCE: Pink esthetic is as important as dental esthetics and some restorative materials can mimic gingival tissue. However, the tested giomer must be indicated with caution, since it presented significant changes after thermal and acid challenges.


Assuntos
Resinas Compostas , Materiais Dentários , Cor , Estética Dentária , Teste de Materiais , Propriedades de Superfície
18.
Am J Dent ; 32(4): 169-173, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31436936

RESUMO

PURPOSE: To evaluate the effect of diamond toothpastes on the gloss surface of five resin composites. METHODS: 30 discs of each resin composite in A2 shade [Filtek Supreme Ultra (FS), Tetric EvoCeram (TE), IPS Empress Direct (ED), Charisma (CC), Venus Diamond (VD)] were made. The samples were divided into three groups according to the toothpaste: Colgate Total Clean Mint (control) (CTC), Candida White Diamond (CWD) and Emoform-F Diamond (EFD). After standardized polishing, the samples were brushed using a toothbrushing simulator, and gloss measurements were assessed at baseline and 15, 30, 45, 60, 75, 90, 105 and 120 minutes. RESULTS: Diamond toothpastes behaved dif-ferently from each other: the CWD and CTC groups presented the lowest values compared to EFD (P< 0.05). Nanofilled composites presented higher gloss values than other composites when brushed with various toothpastes (P< 0.05). The addition of diamond particles as abrasives in toothpastes can affect resin composites' surface gloss. CLINICAL SIGNIFICANCE: The various types of abrasive particles present in toothpastes may harm resin-composite restorations.


Assuntos
Polimento Dentário , Cremes Dentais , Resinas Compostas , Diamante , Teste de Materiais , Propriedades de Superfície
19.
Am J Dent ; 32(4): 187-190, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31436939

RESUMO

PURPOSE: To evaluate the shear bond strength between denture base and artificial teeth subjected to five different modifications on the ridge surface. METHODS: 30 acrylic central anterior teeth were randomly divided into five groups (n= 6). The ridge surface of these teeth were treated with different methods: (1) No treatment applied; (2) Monomer wetting; (3) Grinding; (4) Grinding followed by sandblasting; (5) Grinding followed by monomer wetting. After the ridge surface of the teeth were treated, they were packed with denture base resin. The shear bond strength between acrylic teeth and denture base resin was performed using a universal testing machine. The data was statistically analyzed using one-way ANOVA (P< 0.05). RESULTS: The monomer wetting group showed the highest shear bond strength values, and the grinding followed by sandblasting group was the lowest, both were statistically significant compared to each other. There were no statistical differences between the other groups. CLINICAL SIGNIFICANCE: Treating the surface of the denture ridge with a monomer provided the highest shear bond strength values, and the grinding followed by sandblasting group was the lowest, statistically significant compared to each other.


Assuntos
Resinas Acrílicas , Colagem Dentária , Polímeros , Análise do Estresse Dentário , Bases de Dentadura , Teste de Materiais , Distribuição Aleatória , Resistência ao Cisalhamento , Propriedades de Superfície
20.
Soft Matter ; 15(33): 6630-6641, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31403143

RESUMO

The mechanics of blister delamination and growth plays a major role in a diversity of areas including medicine (skin pathology and mechanics of cell membranes), materials (adhesive and fracture) or soft robotics (actuation and morphing). The behavior of a blister in this context is typically difficult to grasp as it arises from the interplay of two highly nonlinear and time-dependent processes: membrane attachment and decohesion from a substrate. In the present work, we device a simplified approach, based on experimental systems, to predict the deformation path of a blister under various conditions. For this, we consider the problem of a growing blister made of a rubber-like membrane adhered on a rigid substrate, and develop a theoretical and experimental framework to study its stability and growth. We start by constructing a theoretical model of viscoelastic blister growth which we later validate with an experimental setup. We show that blister growth is controlled by the competition between two instabilities: one inherent to the rubber, and a second one pertaining to the adhesion with the substrate. Using these concepts, we show that a "targeted" stable blister shape can be achieved by controlling two parameters: the thickness of the film and the inflation rate.


Assuntos
Simulação por Computador , Membranas Artificiais , Modelos Teóricos , Adsorção , Elasticidade , Cinética , Propriedades de Superfície , Termodinâmica , Viscosidade
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