In this work, three amorphous mesoporous materials (MMD1, MMD2, and MMD3) with different structural characteristics were synthesized and impregnated with 10% of Fe2O3, in-order-to obtain an effective amorphous mesoporous material (MMD) for H2S adsorption. These materials were characterized by using SEM, EDX, TEM, ICP-MS, N2 Adsorption, and DRX. Capacity tests for H2S adsorption were performed to evaluate its performance as adsorbents of this gas. The results showed that the MMD1 mesoporous material impregnated with Fe2O3 showed the highest adsorption capacity of H2S concerning the other materials studied in this work. This material could be a good option to control environmental emissions and improve the quality of the oil and gas.
Bacterial adhesion and biofilm formation on restoration surfaces could lead to secondary caries and even inflammation of pulpal nerve. Finishing and polishing procedures are crucial to form resistance of materials to bacterial adhesion. The aim of the present study is to compare Streptococcus Mutans (S. mutans) adhesion on restorative materials polished with one- or multi-step systems. 2x5 mm disc-shaped samples were prepared from a resin-modified glass ionomer (RMGI), a compomer, a conventional flowable composite and two flowable bulk-fill composites. Specimens of each group were divided into two groups according to polishing systems (n = 9): One-step (OG) or Multi-step (SL) systems. Surface roughness values were examined by profilometry and one sample of each group were examined for bacterial on confocal laser scanning microscope (CLSM). S. mutans counts were calculated by broth cultivation. Results were analyzed with one-way ANOVA and Bonferroni/Dunn tests. Two flowable bulk-fill composites showed superior roughness values than the conventional flowable and RMGI. Specimens polished with OG system had no significant difference among bacterial counts (p>0.05). After polishing with SL system, Tetric Evo Bulk Flow showed significantly the lowest bacterial adhesion followed by the RMGI and the compomer. CLSM images were in consistent with microbiological culture. All tested materials had lower bacterial adhesion when polished with multi-step system. Multi-step systems should be used with flowable bulk-fill composites to have optimum results in terms of lowering bacterial adhesion and improving surface properties. CLSM images supplies accordance with broth culture of S. mutans thus, this method could be useful on detecting bacterial adhesion.
The primary focus of this experiment was to study of optical imaging of malignant and normal tissues (skin and breast) and to observe the spectral properties of Methylene Blue and its potential use as a cancer biomarker in the diagnosis of breast cancer tissues. We present the optical imaging of skin tissues by different techniques, including reflectance, fluorescence and polarization imaging for early detection of skin cancer. We collected the reflectance images of skin between 410 nm and 630 nm. We confirmed that a high concentration of MB occurs in cancer cells due to its increased accumulation in mitochondria of cancer cells. The breast tissues stained with MB were imaged with a high-resolution microscope. Imaging of breast cancer shows highly significant differences between cancer and normal cells using MB concentrations as low as 0.05 and 0.01 mg/ml. We also observed the fluorescence polarization and absorption and fluorescence emission spectrum of MB dissolved in solutions of saline and glycerol by using different solutions of methylene blue dye.
El presente estudio tiene como objetivo caracterizar microestructuralmente y evaluar el comportamiento de las variables acusticas de velocidad longitudinal y coeficiente de atenuacion, de probetas provenientes de barras de acero duplex SAF 2205, sometidas a tratamientos de envejecimiento a 475 °C. Se evaluo la resistencia a la corrosion de las probetas tratadas termicamente y se comparo con la resistencia de la muestra de acero sin tratamiento termico. El estudio contemplo el analisis microestructural mediante microscopia optica y electronica de barrido y la evaluacion ultrasonica a frecuencias de 3.5, 5 y 10 MHz. Finalmente, fueron sometidas a ensayos de corrosion y evaluadas nuevamente por ultrasonido convencional utilizando la tecnica pulso eco de contacto. Los resultados de la evaluacion ultrasonica muestran un aumento de la velocidad de la onda longitudinal, a medida que se incrementa el tiempo de tratamiento. Por otro lado, se reportan mediciones del coeficiente de atenuacion para cada una de las probetas evaluadas, observandose el efecto de los cambios microestructurales que tienen lugar como consecuencia de los tratamientos termicos. En cuanto a los ensayos de corrosion acelerada, en los ensayos de inmersion se aprecio que estos generaron danos en la microestructura de las probetas, al ocasionar picadura en los bordes de grano. Las curvas de polarizacion obtenidas para todas las muestras bajo estudio, no presentaron una zona de pasivacion estable; presentando inestabilidad y rango de ruido en la zona pseudo-pasiva de la curva de polarizacion debido, posiblemente, a una corrosion selectiva en la microestructura del material.
Modern high temperature installations, such as aero-engines and other land-based gas-turbine engines, constitute elevated operation temperatures and lofty pressure ratios, in addition to rotational speeds exceeding 10,000 rpm, necessary for improved engine-efficiencies. Normally, elevated temperatures lead to excessive thermal stresses, while extreme rotational speeds tend to result in tempestuous mechanical stresses, in prohibitively corrosive exhaust gases. Furthermore, high temperatures generally lead to considerable deterioration in material mechanical properties, in addition to a tendency to promoting oxidation damage. Therefore, ideal materials for these applications should exhibit high mechanical-property stability against temperature changes, resistance to oxidation-, fatigue-, and creep-damage. Nickel-based superalloys, materials widely employed for this purpose, are a unique class of materials, designed for manufacture of components that form a backbone of gas turbine-engines. Mechanical behaviour is largely influenced by microstructural features and the synergy between characteristics and constituents of the operating conditions. This paper presents a critical review of the synergetic interaction between mechanical loading and oxidation damage in nickel-based superalloys’ behaviour. The review establishes that although oxygen-rich environments were widely cited for the observed enhanced oxidation damage, crack closure effect, reduced creep-load bearing capabilities and accelerated crack growth, to date, only limited work has been conducted to provide a clearer understanding of the mechanism by which interaction between mechanical loading and oxidation damage, lead to inferior mechanical behaviour. Oxidation appears to be a physical process driven by diffusion of oxygen and alloy elements, which tends to be aggravated by the application of a mechanical load. However, the mechanism by which this happens is still yet to be fully understood.
The purpose of this study was to compare the persistency of selected desensitizing agents after tooth brushing using fluorescence stereo zoom microscope. Forty 5 x 5 x 5-mm dentin discs were prepared from freshly extracted non-carious human first and second premolars and then were randomly divided into four groups (n = 10). Dentin desensitizing agents (All-Bond Universal, Gluma Desensitizer, and BisBlock) were applied with a fluorescent red dye (Rhodamine B). The persistency of the desensitizers was analyzed by fluorescence stereo zoom microscope (AxioZoom) over a period of eight weeks of tooth brushing. The mean florescence intensity (MFI; pixel) values were calculated for each specimen. The results were analyzed using Kruskal–Wallis, Mann–Whitney U, and Wilcoxon signed-rank tests with a significance threshold of p 0.05). However, the MFI values showed a reduction during the eighth week in all groups (p < 0.05). Tooth brushing caused various abrasion levels with the three desensitizing agents used in this study in proportion to time.
Con este trabajo hemos pretendido conocer, la accion de los sueros de celulas madre, producidos por los cultivos de monocitos, procedentes de medula osea, sobre premolares que habian sido lesionados previamente. Se utilizaron 100 µl de cada uno de los sueros VEGF, TGF-β1 y FGFb, respectivamente, obtenidos en los pases 4 y 7 de los cultivos de monocitos medulares. Hemos utilizado 4 perros, de los que se utilizaron los premolares del lado derecho, distribuyendolos en 4 lotes. A los premolares se les realizo un tratamiento que consistio, en una destruccion y sangrado de la pulpa y, posteriormente, un tratamiento con sueros producidos en cultivos de monocitos (CMNs), aleatoriamente a cada premolar. Al grupo control solo se le practico el traumatismo inicial. Se distribuyeron en 4 grupos de experimentacion: Control; 1° con suero VEGF; 2° con suero FGFb; 3° con suero TGF-β1. Comparando con el grupo control, hemos encontrado que en el grupo 1°, la recuperacion se ha llevado a cabo por una activacion del lecho vascular, activando tanto a los odontoblastos como a los fibroblastos, con formacion de fibras de colageno. En el grupo 2°, los capilares son maduros, activandose los odontoblastos, pero las celulas que reaccionan en mayor grado son los fibroblastos, que aumentan sus organoides citoplasmaticos, favoreciendo la sintesis de fibra de colageno. En el grupo 3°, los capilares no fueron tan abundantes como en el 1°, pero con una correcta recuperacion, activando los odontoblastos y la formacion de fibras de colageno.
Localizing, identifying and quantifying lipid droplets are important features to be assessed in the research of mechanisms involved in diseases such as steatosis, obesity, diabetes, myopathies and arteriosclerosis. Lipid-droplet staining with Oil Red O is widely used combined to either light field, conventional fluorescence microscopy and phase contrast microscopy. Here, for the first time, we report an easy, fast and precise protocol for the quantitative evaluation of lipid droplets staining with Oil Red O in HepG2 cells in vitro using confocal laser scanning microscopy associated with maximum intensity projection technique and counting point method. Our methodology was compared to a previous described protocol to measure lipid droplets, based on phase contrast microscopy and binarization. Our protocol substantially enhanced the quality of lipid droplets images compared to phase contrast microscopy by different reasons, such as: 1-Use of maximum intensity projection technique; 2- Out-of-focus light absence; 3-Increased contrast; 4-Enhanced lipid droplet definition. Thus, the use of this protocol increases the sensitivity of lipid droplets quantification, showing morphological results that can be underestimated using other approaches.
Nowadays, there is a big interest in the preparation of mixed oxides with transition metal atoms. Spinel oxides of AB2O4 formula present structural properties that make them attractive in magnetic applications, sensor technology and refractory materials [1]. The nickel aluminate structure NiAl2O4, makes it resistant to acids and alkalis, presents high melting point and surface area, extraordinary catalytic properties and is resistant to deactivation by coke formation [2]. Those properties allow a wide use in the oil industry in processes as hydrogenation, methanation and steam reforming [3, 4]; this material is also employed in high temperature fuel cells and as an anode for the production of aluminum [5]. In this work, we report the production of nickel aluminate nanoparticles (NiAl2O4) with a considerable magnetic field of 137.09 Oe by employing a -300 Hg mm vacuum sol-gel chemical synthesis. The material was evaluated through Differential Scanning Calorimetry, Thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared spectroscopy (FTIR), X-Ray Diffraction analysis (XRD), Scanning Electron Microscopy (SEM), high resolution Transmission Electron Microscopy (HR-TEM) analysis and its magnetic behavior was corroborated by a vibrating sample magnetometer (VSM). Preliminary results show the formation of NiAl2O4 nanocrystals with dimension of 5 to 15 nanometers, homogeneous morphology, inverse spinel structure and weak ferromagnetic behavior with a coercive field (Hc) of 66.29 Oe, a remainder magnetization (Mr) of 7.15 emu/g and a saturation magnetization (Ms) of 71.34 emu/g.
Polygonum istanbulicum, a species endemic to Istanbul was thoroughly examined in this study. Leaf epidermal characteristics, micromorphological structures belonging to stomata, pollen, and seeds were explained with the assistance of several SEM photographs, and the results obtained were compared to similar studies. Additionally, all specific and distinguishing characteristics of the species were also specified.
Sample preparations are essential in scanning electron microscopy. Flawed sample preparations can undermine the quality of results and lead to false conclusions. Thus, the aim of this review is to equip researchers, post graduate students and technicians with the essential knowledge required to prepare samples for scanning electron microscopy investigations in the life sciences.
Tooth extraction wound complications occur in everyday clinical practice and their management can sometime be challenging. The process is followed by the characteristic pathohistological changes occurring in the soft tissue surrounding extraction wound that is known to follow several precisely regulated phases. Coenzyme Q10, omnipresent molecule, was found to potentially influence the wound healing process, however, its usage is limited due to its poor availability after application. This study evaluates for the first time the effects of coenzyme Q10 (free and encapsulated in nanoliposomes) treatment regime on osteopontin expression in the inflammatory cells surrounding rat tooth extraction wound and correlates these findings with the oxidative stress (lipid peroxidation and protein oxidative damage) and inflammation (myeloperoxidase and nitric oxide) related biochemical changes in the same tissue. Our results revealed that the encapsulated coenzyme Q10 is statistically significantly (p<0.001) more potent in preventing tissue inflammation and oxidative damage, as well as to inhibit osteopontin expression. Correlation analysis pointed to the fact the coenzyme Q10 activity is not only related to its impact on inflammatory cells activity but to other types of cells as well. The obtained results suggest the use of coenzyme Q10 in dental practice and as a food supplement should be recommended due to its ability to significantly enhance the wound healing process. This is especially true for the encapsulated form of the coenzyme Q10, which exerted the same extent of healing potential almost two times faster than the free form.
The understanding of the interaction between graphene with chitinous polymers remains a challenge. Herein, we propose the extraction of partially deacetylated chitin from Litopeneaus Vannamei shrimp’s waste (CH30) to produce a nanocomposite film with graphene and compared it with a high deacetylated chitosan (CH75). Structural characterization was carried out by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Raman, Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA-DTG). Our findings reveal the successful functionalization of graphene with chitin to form a nanocomposite film. These findings shed light on the interaction between graphene and chitinous polymers in regards to give an additional value to shrimp shell waste.
Formation of secondary mycogenic minerals, a phenomenon often reported on artworks, is heavily associated with both structural and aesthetic alterations of affected masterpieces. The aim of this study was to investigate capabilities of airborne Aspergillus and Penicillium species, common contaminants of works of art, to induce mineral formation in vitro. For this purpose, tested fungal isolates were cultivated on B4 medium, and optical microscopy and SEM-EDS techniques were applied to observe the morphology of crystals and to discern their chemical composition. Out of 34 isolates in total, mineral formation was documented in 14 Aspergilli and 15 Penicillia species. The predominant crystal in the investigated samples was calcium oxalate, while calcium carbonate crystals were only seldom reported. Biogenesis of secondary mycogenic minerals is probably due to the ability of investigated isolates to excrete different acidic metabolites into the substrata. Investigations of biomineralization of autochthonous airborne fungal isolates must not be neglected for adequate protection of stone-made cultural heritage objects. However, little focus is given to this phenomenon, especially concerning formation of oxalates via fungal metabolites.
SHED is known for its capabilities to extensive proliferation and multipotential differentiation. The utilization of natural scaffold such as amniotic membrane, for SHED differentiation into odontoblast-like cells offers great potential in dental regeneration. This study aims to investigate the ultrastructure transformation during differentiation of SHED into odontoblast-like cells of SHED on AM in vitro using scanning electron microscope (SEM). SHED was cultured on AM scaffold and treated with bone morphogenetic protein-2 (BMP-2) growth factor for 1, 7, 10 and 14 days, respectively. SHED cultured on AM without BMP-2 served as control. Formaldehyde-based protocol was used to fix the samples for imaging. Samples were gold-coated with sputter coating machine SCD 0005 and viewed by SEM FEG450 at 5000x magnification. SEM imaging showed the surface structure of AM was fibrous. Nanofibrous structure is known to facilitate interaction of the cells for adherence and infiltration into this scaffold. SHED displayed cell extensions with small finger-like or web-like projections at the very end of the cell after a day of BMP-2 treatment. On the following days, SHED lost the fibroblast-like morphology, became smaller and round-shaped. Emergence of odontoblast-like cell with columnar cell body and several processes were detected on day 7. By day 14, strong mineralization on the cell body was observed, suggesting a matured odontoblast. In control group, SHED appearance as fibroblast-like cell morphology remained up until day 14 of culture. In conclusion, morphological evaluation via SEM confirms AM support for a complete differentiation of SHED into odontoblast-like cells by day 14 of culture.
Laboratory diagnosis and epidemiological surveillance of cholera in most of the Brazilian Public Health Laboratories have been based on phenotypic characteristics, including antibiotic-resistance testing. These methods are known to be of limited value for predicting the epidemiological potential of Vibrio cholerae strains.
Single-chain antibody fragments are recombinant products of great interest for immunodiagnostics and immunotherapy. A number of systems for the production of Single-chain antibody fragments have been described. Functional s Single-chain antibody fragments have been purified from mammalian cell supernatant cultures and are promising cancer therapy reagents.
Lactobacillus spp.are the most prevalent beer-spoilage bacteria Most bacterial species fail to grow in beer because the hop compounds, added to confer bitter flavour to beer, is the major neutralizing agent for bacteria.
The important role that many of the genomic species of Acinetobacter play in nosocomial infections, together with their ability to develop resistance to many of the commonly used antibiotics makes rapid, reliable epidemiological typing of these organisms a necessity.
Bioremediation techniques, particularly landfarming and vapour extraction, have been used successfully and have been reported to be cost effective. In spite of the success of bioremediation, it is observed that degradation of pollutants in soil is generally slow and needs to be accelerated.
