Search

The presence of heavy metals such as arsenic (As) and chromium (Cr) can be considered one of the most toxic heavy metals. This study aims to develop and evaluate a graphene oxide (GO) based material functionalized with ferrihydrite for the removal of As(V) in the presence of Cr(VI). The adsorbent ferrihydrite-functionalized graphene oxide (GOFH) was characterized by SEM, FTIR, XRD, XPS, surface charge, BET and TGA. Individual adsorption capacities for As(V) and Cr(VI) were 160 and 66 mg g−1 respectively at pH 4 and 298 K, fitting the Langmuir model. In binary systems, GOFH adsorbed As(V) with an adsorption capacity of 137 mg g−1 in the presence of 20 mg L−1 Cr(VI) at room temperature. Thermodynamic analysis revealed an exothermic and spontaneous process. Additionally, GOFH effectively removed several coexisting anions from groundwater, including SO42−, CO32− and Cl−. This work evidences the potential of GOFH for competitive adsorption of priority pollutants from complex matrices. The GOFH material represents a technically and economically viable technology for application in groundwater decontamination, as it requires inexpensive precursors and ambient conditions during synthesis and operation.

ABSTRACTRecovering biocompounds from industrial by-products is crucial to avoid food waste. Microwave-assisted extraction (MAE) has been employed to recover some biocompounds from vegetal matrices using ethanol and his solutions as solvent. Optimization of MAE conditions over total soluble polyphenols (TSP) and antioxidant capacity (DPPH and FRAP) from avocado residual paste (ARP) from oil industry was carried out. Optimal extract was used to elaborate an artisanal ham. Using response surface methodology (RSM), optimal conditions for MAE were 480 W of power, absolute ethanol as solvent, and extraction time of 180 s. The extract contained TSP of 31.24 mg GAE/g DW, DPPH inhibition of 24.51 mg TE/g DW and FRAP inhibition of 21.58 mg TE/g DW. The extract was added in the ham formulation at 0, 0.5, 1, and 1.5% w/w. Ham with 1% extract had the highest scores for acceptance. Extracts from ARP may be used in ham with adequate sensory attributes.

Computational cell segmentation is a vital area of research, particularly in the analysis of images of cancer cells. The use of cell lines, such as the widely utilized HeLa cell line, is crucial for studying cancer. While deep learning algorithms have been commonly employed for cell segmentation, their resource and data requirements can be impractical for many laboratories. In contrast, image processing algorithms provide a promising alternative due to their effectiveness and minimal resource demands. This article presents the development of an algorithm utilizing digital image processing to segment the nucleus and shape of HeLa cells. The research aims to segment the cell shape in the image center and accurately identify the nucleus. The study uses and processes 300 images obtained from Serial Block-Face Scanning Electron Microscopy (SBF-SEM). For cell segmentation, the morphological operation of erosion was used to separate the cells, and through distance calculation, the cell located at the center of the image was selected. Subsequently, the eroded shape was employed to restore the original cell shape. The nucleus segmentation uses parameters such as distances and sizes, along with the implementation of verification stages to ensure accurate detection. The accuracy of the algorithm is demonstrated by comparing it with another algorithm meeting the same conditions, using four segmentation similarity metrics. The evaluation results rank the proposed algorithm as the superior choice, highlighting significant outcomes. The algorithm developed represents a crucial initial step towards more accurate disease analysis. In addition, it enables the measurement of shapes and the identification of morphological alterations, damages, and changes in organelles within the cell, which can be vital for diagnostic purposes.

This work presents an experimental study aimed to determining the influence of the slide burnishing force on the surface roughness indicators ( R a , R z , R t , R v , and R p ) and corrosion resistance on the advanced high strength steels TRIP-440Y and DP-330Y and the high strength steel HSLA-SP780. For each steel, the tests were carried out at different burnishing forces between 30 and 450 N, using a zig-zag burnishing toolpath with a 50% of the footprint width of the spherical tip as length between burnishing traces. The results showed that the optimal burnishing force to minimize surface roughness for HSLA-SP780, DP-330Y, and TRIP-440Y steels were 60, 150, and 180 N. These burnishing forces enhanced the roughness indicators between 40.3% and 73.4% for DP-330Y, from 57.5% to 83.2% for TRIP-440Y, and around 2.8% and 41.6% for HSLA-SP780. Corrosion tests exhibited that sliding burnishing does not affect the corrosion resistance of the steels, which are coated with a zinc layer. This result was confirmed by an X-ray diffraction analysis of the burnished samples. The corrosion current for all samples burnished and not burnished with zinc were close to 25 µA. Therefore, slide burnishing technique is an excellent option to improve the surface roughness without affecting the corrosion resistance of these steels, as well as other mechanical and physical properties that have been investigated according to the literature.

In the present study, the effects of sandblasting on the surface properties of magnesium (Mg) sheets were investigated. A 32 Central Composite Design (CCD) of Experiments was developed and applied to attain reliability, reproducibility, and significance of the experimental results. Following the CCD, pressure and application distance were selected as factors (experimental variables), whereas the surface roughness, hardness, and corrosion current were measured as the response variables (surface properties). Three effects of the factors were studied (pressure change, distance change, and their combined change) through an Analysis of Variance. The charts of the main effects showed that in the case of roughness and corrosion current, the three effects are significant to their modification, i.e., they increase by raising any of the factors or both at the same time. On the other hand, only the pressure is significant for the modification of hardness, this means that hardness can be improved by increasing the pressure, regardless the application distance. Also, it was found that pressure is the key factor for the modification of roughness, hardness, and corrosion current, accounting for a contribution of 57.0%, 72.8%, and 61.0%, respectively. The microstructural analysis showed that sandblasting produces a grain refinement and leaves a deformed crystalline structure in a subsurface layer. Also, for high pressures and short application distances defects such as cracks and voids are generated on the surface. All these microstructural changes correlate to the modification of the surface properties.

This work presents the synthesis of amine and ferrihydrite functionalized graphene oxide for the removal of fluoride from water. The synthesis of the graphene oxide and the modified with amine groups is developed by following the modified Hummer’s method. Fourier transform infrared spectrometry, X-ray, Raman spectroscopy, thermogravimetric analysis, surface charge distribution, specific surface area and porosity, adsorption isotherms, and the van’t Hoff equation are used for the characterization of the synthesized materials. Results show that the addition of amines with ferrihydrite generates wrinkles on the surface layers, suggesting a successful incorporation of nitrogen onto the graphene oxide; and as a consequence, the adsorption capacity per unit area of the materials is increased.

Reducing the content of sucrose and fat in gluten-free products by means of replacers, such as agavin-type fructans (ATF), represents a challenge for the bakery industry, which is still developing products to satisfy the needs of celiac consumers. The aim of this work was to optimize the use of ATF from Agave tequilana Weber var. azul as fat and sucrose replacer in a gluten-free muffin formulation. Using response surface methodology, we obtained two optimal values, one for sucrose replacement (SR) and another one for fat replacement (FR) by ATF. These yielded 28% SR and 22% FR, respectively. SR and FR muffins showed significantly lower height, darker crumb color, slightly yellow crust and crumb, and larger cell area than control. Additionally, FR muffins showed darker crust color while SR muffins showed brighter crust as well as less hardness and springiness. However, this difference was not noticed by the sensory panel. On the other hand, the chemical composition revealed a carbohydrate and fat reduction by 11.5% and 2% in SR and FR product, respectively, in comparison to the control. Therefore, ATF have proven to be a potential functional ingredient to be employed in the development of low-fat and low-sucrose gluten-free bakery products.

Arsenic (As) is a natural contaminant that exists naturally in the earth crust and it is toxic to plant cells. Studies involving the absorption of As by plants have already been described previously. Recently, researchers have intended to understand the molecular and physiological mechanisms that intervene and interact in As absorption. The study of the metabolome in plants under As stress makes use of advances in instrumentation and analytical equipment that allows for metabolomics to be performed. The aim of this comprehensive review is to provide a revision of metabolomic studies related to As-induced stress in plants and the main alterations in its metabolism compared to a non-stress situation. According to the reviewed research, As affects both primary and secondary metabolism, with amino acids, proteins, and the antioxidant complex enzymes being the molecules most studied and related to As stress. However, non-enzymatic compounds, derived from the secondary metabolism, have been scarcely studied in metabolomic studies on As-induced stress in plants. In conclusion, metabolomics as a research approach to studying As stress in plants could permit in-depth understanding of As-related behavior in the plant metabolism

The CoCrMo alloy is a biomaterial that has been employed for the production of permanent orthopedic implants, however, the release of metallic ions from debris due to tribocorrosion is the main drawback for its extended application. In this paper, we propose the use of the ball burnishing process to improve the surface properties of the CoCrMo alloy. A 32 factorial design of experiments (DoE) was conducted to achieve a basic understanding of the relationship between the surface hardness, roughness and corrosion current (response variables) and the force and number of passes of the burnishing tool (input factors). Statistical analysis showed that force is the most significant factor for changing the surface properties. At the best experimental conditions, hardness was improved by 41.4%, the roughness was decreased by 72.7% and the corrosion rate was noticeably reduced by 92.4%. Microscopy and X-ray diffraction analysis showed that ball burnishing introduces changes in the microstructure, generating a surface layer with improved properties. It is concluded that the ball burnishing process is suitable for improving the surface properties of the CoCrMo alloy under an appropriate combination of experimental conditions.

Water contamination around the world is an increasing problem due to the presence of contaminants such as arsenic, fluoride, and chromium. The presence of such contaminants is related to either natural or anthropogenic processes. The above-mentioned problem has motivated the search for strategies to explore and develop technologies to remove these contaminants in water. Adsorption is a common process employed for such proposals due to its versatility, high adsorption capacity, and lower cost. In particular, graphene oxide is a material that is of special interest due to its physical and chemical properties such as surface area, porosity, pore size as well as removal efficiency for several contaminants. This review shows the advances, development, and perspectives of materials based on GO employed for the adsorption of contaminants such as arsenite, arsenate, fluoride, and hexavalent chromium. We provided a detailed discussion of the synthesis techniques and their relationship with the adsorption capacities and other physical properties as well as pH ranges employed to remove the contaminants. It is concluded that the adsorption capacity is not proportional to the surface area in all the cases; instead, the synthesis method, as well as the functional groups, play an important role. In particular, the sol–gel synthesis method shows better adsorption capacities.

Additive manufacturing technologies have facilitated the construction of intricate geometries, which otherwise would be an extenuating task to accomplish by using traditional processes. Particularly, this work addresses the manufacturing, testing, and modeling of thermoplastic polyurethane (TPU) lattices. Here, a discussion of different unit cells found in the literature is presented, along with the based materials used by other authors and the tests performed in diverse studies, from which a necessity to improve the dynamic modeling of polymeric lattices was identified. This research focused on the experimental and numerical analysis of elastomeric lattices under quasi-static and dynamic compressive loads, using a Kelvin unit cell to design and build non-graded and spatially side-graded lattices. The base material behavior was fitted to an Ogden 3rd-order hyperelastic material model and used as input for the numerical work through finite element analysis (FEA). The quasi-static and impact loading FEA results from the lattices showed a good agreement with the experimental data, and by using the validated simulation methodology, additional special cases were simulated and compared. Finally, the information extracted from FEA allowed for a comparison of the performance of the lattice configurations considered herein.

Currently, the presence of arsenic (As) in groundwater is a global concern to agricultural irrigation. It can produce a stressful environment in plants, causing both physiological and metabolic changes. The objective of this study was to evaluate the physiological and metabolic effects derived from As absorption in a hydroponic lettuce crop. A hydroponic system with different concentrations of As (0-16 µM) was used. The physiological development and quality of the crop were evaluated. The absorption of As in vegetal structures was evaluated to obtain the translocation and bioconcentration factors. The lettuce absorbed As in a range of 0.22-2.18 and 1.34-68.23 mg As/kg in leaves and roots, respectively. Arsenic caused a decrease in plant growth (>1 µM As) and biomass (<2 µM As). At 16 µM As, the observed changes were in color and Chlorophyll content of leaves. Phenolic compounds presented activation and inactivation at different As concentrations. The bioaccumulation factor shows that lettuce can efficiently absorb As; however, as it has low translocation factor, it is considered that As absorbed by the plant was not translocated to the aerial part. The study demonstrates the ability of lettuce to withstand As toxicity and still grow to a size suitable for commercial purposes, even under high As concentrations. It highlights the role of hydroponic system in facilitating As absorption, particularly in roots. Even though As accumulates within lettuce structures, it has limited movement within the plant. Notably, the study reports a high bioconcentration factor, suggesting that lettuce could serve as an effective As accumulator. Therefore, lettuce might be a viable option for As remediation due to its ability to absorb substantial amounts. [ABSTRACT FROM AUTHOR]