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1.
PLoS One ; 15(9): e0239732, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32986774

RESUMO

A large assemblage (n = 307) of architectural glasses (tesserae and windows) from the early 8th-century Umayyad residential site at Khirbat al-Minya was analysed by laser ablation inductively coupled plasma mass spectrometry. Trace element patterns are essential to establish the provenance of the base glass, while the comparative evaluation of the colouring and opacifying additives allow us to advance a production model for the manufacture of glass mosaic tesserae during the early Islamic period. The primary glass types are Levantine I and Egypt 1a, as well as a few older, reused tesserae, and Mesopotamian plant ash glass used for amber-coloured window fragments. Chemical data revealed fundamental differences in the colouring and opacification technologies between the Egyptian and Levantine tesserae. Co-variations of lead and bismuth, and copper, tin and zinc in the Egypt 1a tesserae provide first evidence for the production of different mosaic colours in a single workshop, specialising in the manufacture of tesserae of different colours. No such trend is apparent in the Levantine samples. Red, cobalt blue and gold leaf tesserae were found to be exclusively made from a Levantine base glass, indicating that the generation of some colours may have been a specialised process. The same may apply to the amber-coloured window glass fragments of Mesopotamian origin that exhibit very unusual characteristics, combining elevated copper (2% CuO) with an excess in iron oxide (5% Fe2O3). These findings have significant implications for the production model of strongly coloured glass and the exploitation of resources during the early Islamic period.


Assuntos
Arquitetura/história , Vidro/química , Vidro/história , Cor , Corantes/análise , Cobre/análise , Egito , Compostos Férricos/análise , História do Século XVIII , Chumbo/análise , Espectrometria de Massas/métodos , Oriente Médio , Minerais/análise , Estanho/análise , Oligoelementos/análise
2.
J Chromatogr A ; 1627: 461394, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823099

RESUMO

The early identification of unstable glass objects in museum collections is essential for their conservation, but as yet cannot be accomplished straightforwardly. Accordingly, this paper describes the development and validation of a simple protocol for quantitative determination of ions characteristic of the chemical decay of historic glass, using surface swabbing combined with ion-exchange chromatography. The establishment of a robust protocol is an important step in the development of an early warning system for the chemical deterioration of unstable glass. Using a model system, the protocol was validated for specificity, linearity, accuracy, precision, limits of detection, and limits of quantification for 10 anionic species (fluoride, acetate, formate, chloride, nitrite, bromide, nitrate, carbonate, sulfate and phosphate) and 6 cationic species (lithium, sodium, ammonium, potassium, magnesium and calcium). Good validation parameters (R2 > 0.995; RSD < 5%; Recovery 90-100%) were obtained for acetate, formate, nitrite, nitrate, phosphate, lithium, sodium, potassium, magnesium and calcium. Chloride (R2 = 0.934; RSD = 13.6%; recovery 71.4%) and carbonate (R2 = 0.993; RSD = 10.3%; recovery 120%) had poor validation parameters. Sulfate had low recovery (78.2%), but high reproducibility (RSD = 4.32%) with R2 = 0.997. Limits of quantification were below 1 mg/L for all analytes, which is satisfactory for the study of unstable glass in museum collections. The validated sampling protocol was trialled using artificially aged unstable glass fragments, which resulted in a high relative standard deviation (between 1 and 30%). The ability to achieve improved care of historic glass by application of the validated protocol in museum collections is discussed in the context of a pilot study undertaken at the Rijksmuseum, Amsterdam.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Vidro/química , Íons/análise , Cloretos/análise , Cromatografia por Troca Iônica , Fluoretos/análise , Íons/química , Limite de Detecção , Metais/análise , Metais/química , Museus , Nitratos/análise , Reprodutibilidade dos Testes , Propriedades de Superfície
3.
Int J Food Microbiol ; 334: 108804, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-32818764

RESUMO

Listeria monocytogenes can form long-lasting biofilms on food-contact surfaces. Lactic acid bacteria (LAB) have shown promise in antagonizing this microorganism in liquid media. However, the ecological relationships differ when cells are forming biofilms. In this work, we propose the use of Lactobacillus biofilms as surface "conditioners" to modulate the adhesion of L. monocytogenes. For this, the biofilm formation ability of Lactobacillus fermentum MP26 and Lactobacillus salivarius MP14 (human milk origin), fluorescently labeled by transfer of the mCherry-encoding pRCR12 plasmid, was first evaluated. Then, mature biofilms of these strains transformed with pRCR12 for expressing the fluorescent protein mCherry were used as adhesion substrate for GFP-tagged L. monocytogenes Scott A. The resulting biofilms were studied in terms of cellular population and attached biomass (cells plus matrix). Species distribution inside the biofilm structure was revealed by confocal laser scanning microscopy (CLSM). Although none of the Lactobacillus spp. strains reduced the adhesion of L. monocytogenes Scott A, species interactions seem to interfere with the synthesis of extracellular polymeric substances and species distribution inside the biofilms. In dual-species biofilms, CLSM images revealed that Lactobacillus cells were trapping those of L. monocytogenes Scott A. When surfaces were conditioned with Lactobacillus biofilms, the spatial distribution of L. monocytogenes Scott A cells was species-specific, suggesting these interactions are governing the ultimate biofilm structure. The results here obtained open new possibilities for controlling L. monocytogenes dispersal using these Lactobacillus spp. biofilms as a "natural" immobilization way. Whether species interactions could modify the virulence of L. monocytogenes still remains unclear.


Assuntos
Aderência Bacteriana/fisiologia , Biofilmes , Vidro/química , Lactobacillus/fisiologia , Listeria monocytogenes/fisiologia , Biofilmes/crescimento & desenvolvimento , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Humanos , Interações Microbianas
4.
PLoS One ; 15(8): e0237726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813737

RESUMO

In this in vitro study, spherical mesoporous bioactive glass nanoparticle (MBGN) and non-porous bioactive glass nanoparticle (BGN) were fabricated. The impact of mesopores on dentinal tubule occlusion and bioactivity was compared to examine the potential of these materials in alleviating dentine hypersensitivity (DH). MBGN, dense BGN were synthesized by sol-gel methods and characterized. Bioactivity and ion dissolution ability were analyzed. Twenty-four simulated sensitive dentin discs were prepared and randomly divided into three groups (n = 8 each); Group 1, no treatment; Group 2, Dense BGN; Group 3, MBGN. Then, four discs per group were treated with 6wt.% citric acid challenge to determine the acidic resistance. The effects on dentinal tubule occlusion were observed by FESEM. The microtensile bond strength (MTBS) was also measured. Cytotoxicity was examined using the MTT assay. According to the results, dense BGN without mesopore and MBGN with mesopore were successfully fabricated. Dense BGN and MBGN occluded the dentinal tubule before and after acid challenge. However, only MBGN formed a membrane-like layer and showed hydroxyapatite formation after soaking SBF solution. There were no significant differences in MTBS among dense BGN, MBGN (P>0.05). The cell viability was above 72% of both materials. The higher bioactivity of MBGN compared with that of dense BGN arises from the structural difference and it is anticipated to facilitate dentin remineralization by inducing hydroxyapatite deposition within the dentinal tubule.


Assuntos
Dessensibilizantes Dentinários/administração & dosagem , Sensibilidade da Dentina/terapia , Dentina/efeitos dos fármacos , Vidro/química , Nanopartículas/administração & dosagem , Dente Pré-Molar , Dentina/metabolismo , Dessensibilizantes Dentinários/química , Dessensibilizantes Dentinários/farmacocinética , Permeabilidade da Dentina/efeitos dos fármacos , Sensibilidade da Dentina/patologia , Liberação Controlada de Fármacos , Durapatita/metabolismo , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanopartículas/química , Nanopartículas/ultraestrutura , Porosidade , Propriedades de Superfície , Resistência à Tração , Remineralização Dentária/métodos , Difração de Raios X
5.
PLoS One ; 15(8): e0237612, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790731

RESUMO

Seventeen glass vessels and twenty glass beads recovered from the excavations at the ancient city of Malindi and the archaeological site of Mambrui in Kenya, east Africa were analysed using electron probe microanalysis (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results show that all of the glass samples are soda-lime-silica glass. They belong to the high alumina -plant ash glass type, characterised by high alumina and relatively low calcium contents, widely distributed in eastern (10th- 16th centuries AD) and southern Africa (13th - 15th centuries AD), Central Asia (9th- 14th centuries AD) and southeast Asia (12th- 13th centuries AD), made with plant ashes and sands. This is an understudied glass type for which previous research has indicated there were three types. When compared with published research on such glasses using Zr, Ti, Ba, Cr, La, Li, Cs, Na2O, MgO and CaO we have identified at least four different compositional groups of v-Na-Al glass: Types A, B, C and D. By comparing the results with contemporary v-Na-Al glass vessels and beads from Central Asia, Africa, and southeast Asia we show that most of the Malindi and Mambrui glass share similar characteristics to the compositions of Mapungubwe Oblate and some of the Madagascar glass beads from southern Africa. They belong to Type A v-Na-Al glass which is characterised by an elevated level of Ti and Ba and a relatively high ratios of Cr/La, relatively low Zr concentrations and low ratios of Zr/Ti. Differences in Zr, Li, MgO and Na2O concentrations in Type A glass indicates that there are subgroups which might derive from different glass workshop(s) specialising in Type A v-Na-Al glass production. Comparison with the chemical compositions of glass from Ghazni, Afghanistan and Termez, Uzbekistan, and by using lead isotope analysis, we suggest v-Na-Al glass was manufactured in Central Asia and possibly worked into vessels and beads there.


Assuntos
Compostos de Cálcio/química , Vidro/química , Óxidos/química , Plantas/química , Dióxido de Silício/química , Hidróxido de Sódio/química , Oligoelementos/análise , Oligoelementos/história , África Oriental , Óxido de Alumínio , Arqueologia , História do Século XV , História do Século XVI , Oceano Índico , Marcação por Isótopo/métodos , Quênia , Espectrometria de Massas
6.
J Vis Exp ; (160)2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32628168

RESUMO

For biomedical applications, metal oxide nanoparticles such as iron oxide and manganese oxide (MnO), have been used as biosensors and contrast agents in magnetic resonance imaging (MRI). While iron oxide nanoparticles provide constant negative contrast on MRI over typical experimental timeframes, MnO generates switchable positive contrast on MRI through dissolution of MnO to Mn2+ at low pH within cell endosomes to 'turn ON' MRI contrast. This protocol describes a one-pot synthesis of MnO nanoparticles formed by thermal decomposition of manganese(II) acetylacetonate in oleylamine and dibenzyl ether. Although running the synthesis of MnO nanoparticles is simple, the initial experimental setup can be difficult to reproduce if detailed instructions are not provided. Thus, the glassware and tubing assembly is first thoroughly described to allow other investigators to easily reproduce the setup. The synthesis method incorporates a temperature controller to achieve automated and precise manipulation of the desired temperature profile, which will impact resulting nanoparticle size and chemistry. The thermal decomposition protocol can be readily adapted to generate other metal oxide nanoparticles (e.g., iron oxide) and to include alternative organic solvents and stabilizers (e.g., oleic acid). In addition, the ratio of organic solvent to stabilizer can be changed to further impact nanoparticle properties, which is shown herein. Synthesized MnO nanoparticles are characterized for morphology, size, bulk composition, and surface composition through transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy, respectively. The MnO nanoparticles synthesized by this method will be hydrophobic and must be further manipulated through ligand exchange, polymeric encapsulation, or lipid capping to incorporate hydrophilic groups for interaction with biological fluids and tissues.


Assuntos
Hidroxibutiratos/química , Compostos de Manganês/química , Manganês/química , Nanopartículas Metálicas/química , Óxidos/química , Pentanonas/química , Temperatura , Vidro/química , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas Metálicas/ultraestrutura , Nitrogênio/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Água/química , Difração de Raios X
7.
PLoS One ; 15(7): e0227395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628681

RESUMO

The FluidFM enables the immobilization of single cells on a hollow cantilever using relative underpressure. In this study, we systematically optimize versatile measurement parameters (setpoint, z-speed, z-length, pause time, and relative underpressure) to improve the quality of force-distance curves recorded with a FluidFM. Using single bacterial cells (here the gram negative seawater bacterium Paracoccus seriniphilus and the gram positive bacterium Lactococcus lactis), we show that Single Cell Force Spectroscopy experiments with the FluidFM lead to comparable results to a conventional Single Cell Force Spectroscopy approach using polydopamine for chemical fixation of a bacterial cell on a tipless cantilever. Even for the bacterium Lactococcus lactis, which is difficult to immobilze chemically (like seen in an earlier study), immobilization and the measurement of force-distance curves are possible by using the FluidFM technology.


Assuntos
Aderência Bacteriana , Lactococcus lactis/fisiologia , Microscopia de Força Atômica/métodos , Paracoccus/fisiologia , Células Imobilizadas/fisiologia , Vidro/química , Indóis/química , Polímeros/química , Água do Mar/microbiologia , Análise de Célula Única , Propriedades de Superfície , Titânio/química
8.
Niger J Clin Pract ; 23(7): 950-956, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32620724

RESUMO

Background: During post restoration, different root structures require several types of posts to increase duration of their clinical use. Several materials have been investigated to enhance their quality and optimize their length according to the available root canal. Aims: The aim of this study was to determine the effect of zirconia, fiber, and ceromer posts with 3- and 6-mm post sizes on the bonding strength of them to root canal dentinal wall with the means of pull-out bond strength test. Methods: Forty-eight single-rooted mandibular human premolar teeth were collected and prepared for this in vitro study. With resin cement, 3- and 6-mm study posts including zirconia, fiber, and ceromer were luted to prepare teeth. For the retention testing, the pull-out force was applied to each specimen parallel to longitudinal axis of both the post and tooth. Results: Both type of materials and size of posts changed the value of bonding strength. In all the post types, 6-mm ones performed better. Overall, the best bonding strength was obtained with fiber posts and the better bonding strength was obtained with zirconia; however, ceromer provided the least bonding strength. Conclusion: Current experiments supported that 6-mm post size can increase the bonding between root canal dentin and studied posts. When considering post materials, fiber provided the best bonding strength in current laboratory setup. Second, zirconia had meaningfully acceptable bonding strength; however, the bonding strength of ceromer posts was not favorable. Further studies optimizing post fabrication techniques of root materials may increase the bonding strength of posts to human dentin to an acceptable clinical degree.


Assuntos
Colagem Dentária , Cavidade Pulpar , Dentina , Técnica para Retentor Intrarradicular , Cimentos de Resina/química , Tratamento do Canal Radicular/métodos , Raiz Dentária/cirurgia , Cerâmica , Resinas Compostas , Vidro/química , Humanos , Teste de Materiais , Zircônio
9.
J Appl Oral Sci ; 28: e20190384, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32520077

RESUMO

OBJECTIVES: This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats' molars undergoing dental bleaching with hydrogen peroxide (H2O2). METHODOLOGY: The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05). RESULTS: At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05). CONCLUSION: A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.


Assuntos
Polpa Dentária/efeitos dos fármacos , Vidro/química , Peróxido de Hidrogênio/química , Pulpite/prevenção & controle , Clareadores Dentários/química , Clareamento Dental/métodos , Animais , Polpa Dentária/patologia , Peróxido de Hidrogênio/efeitos adversos , Masculino , Dente Molar , Pulpite/induzido quimicamente , Pulpite/patologia , Distribuição Aleatória , Ratos Wistar , Reprodutibilidade dos Testes , Fatores de Tempo , Clareamento Dental/efeitos adversos , Clareadores Dentários/efeitos adversos , Resultado do Tratamento
10.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 34(5): 660-666, 2020 May 15.
Artigo em Chinês | MEDLINE | ID: mdl-32410437

RESUMO

Objective: To summarize the clinical application and research status of bioactive glass (BAG) in bone repair. Methods: The recently published literature concerning BAG in bone repair at home and abroad was reviewed and summarized. Results: BAG has been widely used in clinical bone repair with a favorable effectiveness. In the experimental aspect, to meet different clinical application needs, BAG has been prepared in different forms, such as particles, prosthetic coating, drug and biological factor delivery system, bone cement, and scaffold. And the significant progress has been made. Conclusion: BAG has been well studied in the field of bone repair due to its excellent bone repair performance, and it is expected to become a new generation of bone repair material.


Assuntos
Cimentos para Ossos/química , Osso e Ossos , Vidro/química , Osso e Ossos/cirurgia , Humanos , Teste de Materiais
11.
Phys Med Biol ; 65(7): 075010, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32242527

RESUMO

Microbeam radiation therapy (MRT) utilizes highly collimated synchrotron generated x-rays to create narrow planes of high dose radiation for the treatment of tumors. Individual microbeams have a typical width of 30-50 µm and are separated by a distance of 200-500 µm. The dose delivered at the center of the beam is lethal to cells in the microbeam path, on the order of hundreds of Grays (Gy). The tissue between each microbeam is spared and helps aid in the repair of adjacent damaged tissue. Radiation interactions within the peak of the microbeam, such as the photoelectric effect and incoherent (atomic Compton) scattering, cause some dose to be delivered to the valley areas adjacent to the microbeams. As the incident x-ray energy is modified, radiation interactions within a material change and affect the probability of interactions, as well as the directionality and energy of ionizing particles (electrons) that deposit energy in the valley regions surrounding the microbeam peaks. It is crucial that the valley dose between microbeams be minimal to maintain the effectiveness of MRT. Using a monochromatic x-ray source with x-ray energies ranging from 30 to 150 keV, a detailed investigation into the effect of incident x-ray energy on the dose profiles of microbeams was performed using samarium doped fluoroaluminate (FA) glass as the medium. All dosimetric measurements were carried out using a purpose-built fluorescence confocal microscope dosimetric technique that used Sm-doped FA glass plates as the irradiated medium. Dose profiles are measured over a very a wide range of x-ray energies at micrometer resolution and dose distribution in the microbeam are mapped. The measured microbeam profiles at different energies are compared with the MCNP6 radiation transport code, a general transport code which can calculate the energy deposition of electrons as they pass through a given material. The experimentally measured distributions can be used to validate the results for electron energy deposition in fluoroaluminate glass. Code validation is necessary for using transport codes in future treatment planning for MRT and other radiation therapies. It is shown that simulated and measured micro beam-profiles are in good agreement, and micrometer level changes can be observed using this high-resolution dosimetry technique. Full width at 10% of the maximum peak (FW@10%) was used to quantify the microbeam width. Experimental measurements on FA glasses and simulations on the dependence of the FW@10% at various energies are in good agreement. Simulations on energy deposited in water indicate that FW@10% reaches a local minimum around energies 140 keV. In addition, variable slit width experiments were carried out at an incident x-ray energy of 100 keV in order to determine the effect of the narrowing slit width on the delivered peak dose. The microbeam width affects the peak dose, which decreases with the width of the microbeam. Experiments suggest that a typical microbeam width for MRT is likely to be between 20-50 µm based on this work.


Assuntos
Alumínio/química , Flúor/química , Vidro/química , Método de Monte Carlo , Doses de Radiação , Samário/química , Terapia por Raios X , Radiometria , Dosagem Radioterapêutica , Síncrotrons
12.
Chem Commun (Camb) ; 56(40): 5393-5396, 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32285901

RESUMO

A cytochrome c (Cyt c)-modified glass nanopore sensing platform was constructed to sensitively detect glucose in single cells based on changes in the ionic current rectification (ICR) of the system. A difference in glucose content between single H8 and HeLa cells in their satiety or starvation states was clearly able to be detected using this method.


Assuntos
Vidro/química , Glucose/análise , Nanoporos , Análise de Célula Única/métodos , Citocromos c/química , Técnicas Eletroquímicas/métodos , Glucose/química , Glucose Oxidase/química , Células HeLa , Humanos , Peróxido de Hidrogênio/química , Proteínas Imobilizadas/química , Limite de Detecção , Oxirredução
13.
Biofouling ; 36(2): 234-244, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32321306

RESUMO

This study evaluated adhesion and biofilm formation by Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis on surfaces of titanium (Ti) and titanium coated with F18 Bioactive Glass (BGF18). Biofilms were grown and the areas coated with biofilm were determined after 2, 4 and 8 h. Microscopy techniques were applied in order to visualize the structure of the mature biofilm and the extracellular matrix. On the BGF18 specimens, there was less biofilm formation by C. albicans and S. epidermidis after incubation for 8 h. For P. aeruginosa biofilm, a reduction was observed after incubation for 4 h, and it remained reduced after 8 h on BGF18 specimens. All biofilm matrices seemed to be thicker on BGF18 surface than on titanium surfaces. BGF18 showed significant anti-biofilm activity in comparison with Ti in the initial periods of biofilm formation; however, there was extensive biofilm after incubation for 48 h.


Assuntos
Materiais Biocompatíveis/química , Biofilmes/crescimento & desenvolvimento , Vidro/química , Próteses e Implantes/microbiologia , Titânio/química , Candida albicans/crescimento & desenvolvimento , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus epidermidis/crescimento & desenvolvimento , Propriedades de Superfície
14.
BMC Oral Health ; 20(1): 49, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32046691

RESUMO

BACKGROUND: This study investigated the remineralisation effect of bioactive glass on artificial dentine caries. METHODS: Dentine disks with artificial caries were treated with bioactive glass (group BAG), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (group CPP-ACP), sodium fluoride glycerol (group F) or deionized water (group W). All disks were subjected to pH cycling for 28 days subsequently. The topography, microhardness and remineralisation depth of the dentine carious lesion were assessed by atomic force microscopy (AFM), microhardness testing and confocal laser scanning microscope (CLSM), respectively. RESULTS: AFM images indicated mineral depositions on the surface of the carious lesion in group BAG. The changes of Vickers hardness number (ΔVHN, mean ± SD) after pH cycling were 9.67 ± 3.60, 6.06 ± 3.83, 5.00 ± 2.19 and - 1.90 ± 2.09 (p < 0.001) in group BAG, group CPP-ACP, group F and group W, respectively. The remineralisation depth (mean ± SD) of the carious lesion in group BAG, group CPP-ACP, group F and group W were 165 ± 11 µm, 111 ± 11 µm, 75 ± 6 µm and 0 µm (p < 0.001), respectively. CONCLUSION: Bioactive glass possessed a promising remineralisation effect on artificial dentine caries and could be a therapeutic choice for caries management.


Assuntos
Caseínas/farmacologia , Cárie Dentária/tratamento farmacológico , Esmalte Dentário/efeitos dos fármacos , Dentina/efeitos dos fármacos , Vidro/química , Remineralização Dentária , Caseínas/uso terapêutico , Dureza , Humanos , Fluoreto de Sódio
15.
Sensors (Basel) ; 20(4)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32054134

RESUMO

The incidence of oral squamous cell carcinoma (OSCC), which is one of the most common cancers worldwide, has been increasing. Serum anti-p53 autoantibody is one of the most sensitive biomarkers for OSCC. Currently, the most commonly used method on clinical screening platforms is the enzyme-linked immunosorbent assay, owing to its high specificity and repeatability. However, conducting immunoassays on 96-well plates is typically time consuming, thereby limiting its clinical applications for fast diagnosis and immediate prognosis of rapidly progressive diseases. The present study performed immunoassays in glass capillaries of 1-mm internal diameter, which increases the surface to volume ratio of the reaction, to shorten the time needed for immunoassay. The immunoassay was automated while using linear motorized stages and a syringe pump. The results indicated that, when compared with the 96-well plate immunoassay, the glass capillary immunoassay decreased the reaction time from typical 120 min to 45 min, reduced the amount of reagent from typical 50 µL to 15 µL, and required only simple equipment setup. Moreover, the limit of detection for glass capillary anti-p53 autoantibody immunoassay was 0.46 ng mL-1, which is close to the 0.19 ng mL-1 value of the conventional 96-well plate assay, and the glass capillary method had a broader detection range. The apparatus was used to detect the serum anti-p53 autoantibody concentration in clinical patients and compare its results with the conventional 96-well plate method results, which suggested that both of the methods detect the same trend in the relative concentration of serum anti-p53 autoantibody in healthy individuals or patients with OSCC.


Assuntos
Autoanticorpos/sangue , Carcinoma de Células Escamosas/diagnóstico , Imunoensaio/métodos , Neoplasias Bucais/diagnóstico , Proteína Supressora de Tumor p53/imunologia , Automação , Biomarcadores/sangue , Vidro/química , Humanos , Imunoensaio/instrumentação , Limite de Detecção
16.
Environ Pollut ; 259: 113874, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32032982

RESUMO

Pieces of glass as solid wastes were recycled in the synthesis of highly order MCM-41 that decorated by green fabricated Co3O4 nanoparticles using the green extract of green tea leaves forming novel green nano-composite. The synthetic Co3O4/MCM-41 exhibit high surface area, low bandgap energy (1.63 eV), and typical spherical morphology decorated by Co3O4 nanoparticles. The composite was evaluated as green photocatalyst in effective oxidation of methyl parathion pesticide in the presence of a visible light source. The degradation results revealed complete removal of 50 mg/L and 100 mg/L after 60 min and 90 min, respectively using 0.25 of the catalyst at pH 8. The detection of the TOC in the treated methyl parathion solution gives strong indications about the formation of organic intermediate compounds during the oxidation steps. The main detected intermediate compound are C6H5OH(NO2), C6H5OH, (CH3O)3P(S), C6H4(OH)2, C6H3(OH)3, C6H4(NH2)OP(O)(OCH3)2, (CH3O)2P(O)OH, (CH2)2C(OH)OH(CHO)OC(O), and HO2C(CH2)2C(O)CHO. The detected intermediate compounds converted into SO42-, PO43-, NO3-, and CO2 under the extensive photocatalytic of them over Co3O4/MCM-41. The oxidizing species trapping test verified the controlling of the methyl parathion degradation pathway by the hydroxyl radicals. Finally, the composite showed significant reusability properties and applied five times in the oxidation of methyl parathion with considerable degradation percentages.


Assuntos
Cobalto , Metil Paration , Nanopartículas , Óxidos , Praguicidas , Dióxido de Silício , Purificação da Água , Água , Cobalto/química , Vidro/química , Metil Paration/química , Nanopartículas/química , Oxirredução , Óxidos/química , Praguicidas/química , Dióxido de Silício/química , Água/química , Purificação da Água/métodos
17.
Braz Oral Res ; 34: e004, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32022223

RESUMO

The aim of this study was to analyze the structural, morphological and mechanical properties of two different lithium disilicate glass-reinforced ceramics for CAD-CAM systems (IPS e.max CAD and Rosetta SM). Five methodologies were used for both ceramics: microstructure (n = 2) was analyzed using x-ray diffraction (XRD); morphological properties (n = 2) were analyzed by scanning electron microscopy (SEM), with and without hydrofluoric etching; porosity (n = 3) was assessed using 3D micro-computed tomography (micro-CT); flexural strength was measured (n =1 0) using the three-point bending test; and bond strength was determined with self-adhesive resin cement (n = 10), using a microshear bond test. After performing all the tests, the data were analyzed using t-Student test and two-way ANOVA. All the tests used a significance level of α = 0.05. High peak positions corresponding to standard lithium metasilicate and lithium disilicate with similar intensities were observed for both ceramics in the XRD analysis. Morphological analysis showed that the crystalline structure of the two ceramics studied showed no statistical difference after acid etching. Additionally, no significant differences were recorded in the number or size of the pores for the ceramics evaluated. Moreover, no differences in flexural strength were found for the ceramic materials tested, or in the bond strength to ceramic substrates for the resin cements. Based on the study results, no significant differences were found between the two CAD-CAM lithium disilicate glass-reinforced ceramics tested, since they presented similar crystalline structures with comparable intensities, and similar total porosity, flexural strength and bond strength.


Assuntos
Cerâmica/química , Desenho Assistido por Computador , Porcelana Dentária/química , Vidro/química , Análise de Variância , Colagem Dentária/métodos , Resistência à Flexão , Teste de Materiais , Microscopia Eletrônica de Varredura , Porosidade , Valores de Referência , Reprodutibilidade dos Testes , Cimentos de Resina/química , Resistência ao Cisalhamento , Propriedades de Superfície , Difração de Raios X
18.
J Photochem Photobiol B ; 204: 111799, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32018156

RESUMO

CdSe/CdS core shelled quantum dots (QDs) were prepared by colloidal synthesis using a binary ligand system and a non-coordinating, reusable solvent n-octadecane (nOD). Both the synthesis of CdSe and CdSe/CdS core shelled quantum dots were achieved by hot injection technique at much lower temperatures than reported earlier. The use of binary ligand facilitated enough nucleation and growth. Red shift in absorption spectra, an enhanced crystallite and particle size is evidenced by XRD and TEM respectively, confirming the formation of core shell structure of CdSe/CdS. The synthesized core shells exhibited high fluorescence intensity, long term stability and good mono dispersion, making it a potential material for bio-imaging and sensing. Core shell QDs were modified with mercapto propionic acid (MPA) to impart aqueous solubility. Studies on cytotoxicity of shelled QDs reveal good bio compatibility with a very minimum toxicity of IC50 = 20 µg/L. These QDs were used for sensing E. coli. Ordinary glass slide, modified using plasma etching is surface modified through APTES aiding conjugation of antibodies. Anti- E. coli polyclonal antibody on glass matrix (slide) and antibody conjugated QDs were used for detection of E. coli in a typical sandwich model. The excellent optical transparency of glass and high emission of QDs lead to detection of E.coli with a limit of detection of 50 CFU/mL.


Assuntos
Escherichia coli/efeitos dos fármacos , Vidro/química , Pontos Quânticos/química , Animais , Compostos de Cádmio/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Camundongos , Microscopia de Fluorescência , Pontos Quânticos/toxicidade , Compostos de Selênio/química , Sulfetos/química , Propriedades de Superfície
19.
PLoS One ; 15(2): e0227895, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32012168

RESUMO

Skin crack defects can develop in sandwich honeycomb composite structures during service life due to static and impact loads. In this study, the fracture behavior of sandwich honeycomb composite (SHC) beams containing crack at the skin was investigated experimentally and numerically under four-point loading. Three different arrangements of unidirectional (UD) carbon fiber composite and the triaxially woven (TW) fabric were considered for the skins. The presence of a 10 mm crack at mid-span of the top skin, mid-span of the bottom skin, and mid-way between load and support of the top skin, respectively, were considered. Failure load equations of the load initiating the skin crack extension were analytically derived and then numerically developed using the J-integral approach. The crack extension failure mode dominated all cracked specimens except those with low-stiffness skin which were controlled by the compressive skin debonding and core shear failures.


Assuntos
Fibra de Carbono/química , Materiais de Construção , Estresse Mecânico , Alumínio/química , Vidro/química , Humanos , Teste de Materiais
20.
Molecules ; 25(2)2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31968695

RESUMO

This review will show how solid state nuclear magnetic resonance (NMR) has contributed to a better understanding of the borophosphate glass structure. Over the last fifteen years, 1D and 2D magic angle spinning (MAS)-NMR has been used to produce key information about both local and medium range organization in this type of glass. After a brief presentation on borophosphate glasses, the paper will focus on the description of the local order of phosphate and borate species obtained by 1D 31P-and 11B-MAS-NMR experiments, with a special emphasis on the improvements obtained at high magnetic fields on the borate speciation description. The last part of this review will show how correlation NMR provided new insights into the intermediate length scale order. Special attention will be paid to the quantitative data retrieved from 11B/31P REDOR-based NMR sequences and to the qualitative connectivity schemes observed on the 2D 11B/31P maps edited with the heteronuclear multiple quantum coherence (HMQC) NMR techniques.


Assuntos
Boro/química , Vidro/química , Fosfatos/química , Espectroscopia de Ressonância Magnética , Modelos Químicos
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