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471.
Leticia Romero‐Cedillo Hector M Poggi‐Varaldo Teresa Ponce‐Noyola Elvira Ríos‐Leal Ana C Ramos‐Valdivia Carlos M Cerda‐García Rojas José Tapia‐Ramírez 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2017,92(5):937-958
The organic fraction of municipal solid waste (OFMSW), mainly composed of lignocellulosic polymers, is extremely complex. Therefore, it is necessary to apply pretreatments to remove the lignin content and decrease the cellulose crystallinity in order to use the OFMSW for gas biofuels production in the context of biorefineries from waste. This work focused on critically reviewing the conventional pretreatments applied to OFMSW, with the goal of improving the H2 production, as well as other biofuels in modern biorefineries. There are a wide variety of pretreatments that have successfully been used, mainly alkaline, milling and dilute acid. In addition, some research has focused on the recovery and reutilization of the alkali, acid or solvents after the pretreatment, to be incorporated into new cycles of production, minimizing the environmental impacts. Moreover, it would be necessary to incorporate analytical tools, in order to determine the sustainability of the biorefinery project. It is concluded that waste pretreatments could significantly contribute to increased yields of biogas fuels in organic waste‐based biorefineries. Therefore, establishing preliminary stages for conditioning biomass or wastes is essential to improve the degradation of wastes and bio‐product generation. © 2016 Society of Chemical Industry 相似文献
472.
Ping Song Giovanniantonio Natale Jingyi Wang Toby Bond Hossein Hejazi Hector de la Hoz Siegler Ian Gates Qingye Lu 《Advanced Materials Interfaces》2019,6(2)
Metal–organic framework nanosheets (MOF NSs) have drawn a lot of attention lately; however, the interfacial behavior of these 2D MOFs has rarely been investigated. Here, the partition and distribution of 2D NS and 3D nanoparticle (NP) of copper benzenedicarboxylate (CuBDC) at the oil/water interface are imaged by cryo‐scanning electron microscopy. A layer of ≈20 nm NS‐CuBDC is detected with a lateral orientation along the interface, which is attributed to the existence of relatively hydrophobic planes and hydrophilic edges in NS‐CuBDC. The highly hydrophilic CuBDC localizes along the interface within the water phase. The self‐assembly of NS‐CuBDC is found to be a facile method to construct small cubical NPs. The exchange of water into CuBDC leads to super hydrophilic wettability. Ascribed to their amphiphilic properties, NP‐CuBDC acts as sole stabilizer to form stable oil‐in‐water emulsions. Synchrotron‐based computed tomography is used to characterize the 3D distribution of CuBDC in emulsions at room temperature. This work provides great insights in the fundamental study of MOFs at the oil/water interface and may lead to further development of ultrathin 2D MOF membranes. 相似文献
473.
Chong Wang Yanan Wang Xinghua Su Viktor G. Hadjiev Shenyu Dai Zhaojun Qin Hector A. Calderon Benavides Yizhou Ni Qiang Li Jie Jian Md. Kamrul Alam Haiyan Wang Francisco C. Robles Hernandez Yan Yao Shuo Chen Qingkai Yu Guoying Feng Zhiming Wang Jiming Bao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(33)
Since the first report of the green emission of 2D all‐inorganic CsPb2Br5, its bandgap and photoluminescence (PL) origin have generated intense debate and remained controversial. After the discovery that PL centers occupy only specific morphological structures in CsPb2Br5, a two‐step highly sensitive and noninvasive optical technique is employed to resolve the controversy. Same‐spot Raman‐PL as a static property–structure probe reveals that CsPbBr3 nanocrystals are contributing to the green emission of CsPb2Br5; pressure‐dependent Raman‐PL with a diamond anvil cell as a dynamic probe further rules out point defects such as Br vacancies as an alternative mechanism. Optical absorption under hydrostatic pressure shows that the bandgap of CsPb2Br5 is 0.3–0.4 eV higher than previously reported values and remains nearly constant with pressure up to 2 GPa in good agreement with full‐fledged density functional theory (DFT) calculations. Using ion exchange of Br with Cl and I, it is further proved that CsPbBr3?x Xx (X = Cl or I) is responsible for the strong visible PL in CsPb2Br5?x Xx . This experimental approach is applicable to all PL‐active materials to distinguish intrinsic defects from extrinsic nanocrystals, and the findings pave the way for new design and development of highly efficient optoelectronic devices based on all‐inorganic lead halides. 相似文献
474.
Fernando D. Cortes-Vega Wenli Yang Juan Zarate-Medina Stanko R. Brankovic Hector A. Calderon Francisco C. Robles Hernandez 《Journal of the American Ceramic Society》2019,102(3):976-980
In this work we present a unique method to synthesize χ-Al2O3 and α-Al2O3 doped with Cr3+ (ruby). The ruby is synthesized by mechanical milling of pseudoboehmite that is doped in-situ with chromium. The doping is carried by adding chromium sulfate hydrate to an aqueous solution rich in aluminum sulfate hydrate. The pH in the solution is controlled to be between 9 and 10 by using ammonia, which induces the pseudoboehmite precipitation. The Cr3+ is added for its remarkable effects on the detectability of ruby emitting luminescent R1 and R2 bands that are traceable in Raman spectroscopy. The formation of ruby is detected at milling times as short as 5 hours and increased with the milling time. Ruby phase is further confirmed by means of true atomic resolution Transmission Electron Microscopy (TEM). 相似文献
475.
Flávio A. de Freitas Rafael C. Araújo Elzalina R. Soares Rita C. S. Nunomura Felipe M. A. da Silva Sarah R. S. da Silva Antonia Q. L. de Souza Afonso D. L. de Souza Francisco Franco‐Montalbán Leonard D. R. Acho Emerson S. Lima Giovana A. Bataglion Hector H. F. Koolen 《Journal of Food Biochemistry》2018,42(1)
Bacuri, ingá, and uchi are Amazon fruits consumed specially in the North region of Brazil. Due to their large consumption and the lack of knowledge regarding its chemical composition, these fruits were studied in relation to their Antioxidant chemical constitution. The total phenolic content ranged from 3.86 ± 0.47 to 33.38 ± 1.51 mg GAE/100 g, and the total flavonoid content ranged from 1.75 ± 0.22 to 19.44 ± 0.87 mg QUERE/100 g, where the contents showed a significant correlation with DPPH and ABTS antioxidant assays. Thus, UHPLC‐MS/MS was applied do quantify selected compounds, been citric acid the most abundant for all fruits. Furthermore, samples were screened for their α‐glycosidase and lipase inhibitory effects, in addition to their antimicrobial potentials. Bacuri showed the highest antioxidant and α‐glycosidase inhibitory capacity (IC50 15.20 μg/mL), whereas uchi and its main metabolite bergenin displayed moderate antimicrobial activities. The results shed light into the potentials of Amazonian fruit sources.
Practical applications
Plant phenolics are essential components of functional foods, due to their antioxidant and enzyme inhibition activities, which are directly linked to several diseases prevention. This is the first study about the quantification of antioxidant compounds in the Amazonian fruits: bacuri, ingá, and uchi. Although they are quite consumed in the North region of Brazil, there are no bio‐products made from them. This study aimed to elucidate the knowledge about the chemical composition and potentialities within these fruits with the practical purpose of highlighting them to future commercial applications. In addition, once we indicate their capabilities, we contribute with local populations in respect to the production of such fruits, which still is a family activity. 相似文献476.
Julia Hernandez-Baixauli Nerea Abasolo Hector Palacios-Jordan Elisabet Foguet-Romero David Suol Mar Galofr Antoni Caimari Laura Baselga-Escudero Josep M Del Bas Miquel Mulero 《International journal of molecular sciences》2022,23(5)
Chronic inflammation is an important risk factor in a broad variety of physical and mental disorders leading to highly prevalent non-communicable diseases (NCDs). However, there is a need for a deeper understanding of this condition and its progression to the disease state. For this reason, it is important to define metabolic pathways and complementary biomarkers associated with homeostatic disruption in chronic inflammation. To achieve that, male Wistar rats were subjected to intraperitoneal and intermittent injections with saline solution or increasing lipopolysaccharide (LPS) concentrations (0.5, 5 and 7.5 mg/kg) thrice a week for 31 days. Biochemical and inflammatory parameters were measured at the end of the study. To assess the omics profile, GC-qTOF and UHPLC-qTOF were performed to evaluate plasma metabolome; 1H-NMR was used to evaluate urine metabolome; additionally, shotgun metagenomics sequencing was carried out to characterize the cecum microbiome. The chronicity of inflammation in the study was evaluated by the monitoring of monocyte chemoattractant protein-1 (MCP-1) during the different weeks of the experimental process. At the end of the study, together with the increased levels of MCP-1, levels of interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-α) and prostaglandin E2 (PGE2) along with 8-isoprostanes (an indicative of oxidative stress) were significantly increased (p-value < 0.05). The leading features implicated in the current model were tricarboxylic acid (TCA) cycle intermediates (i.e., alpha-ketoglutarate, aconitic acid, malic acid, fumaric acid and succinic acid); lipids such as specific cholesterol esters (ChoEs), lysophospholipids (LPCs) and phosphatidylcholines (PCs); and glycine, as well as N, N-dimethylglycine, which are related to one-carbon (1C) metabolism. These metabolites point towards mitochondrial metabolism through TCA cycle, β-oxidation of fatty acids and 1C metabolism as interconnected pathways that could reveal the metabolic effects of chronic inflammation induced by LPS administration. These results provide deeper knowledge concerning the impact of chronic inflammation on the disruption of metabolic homeostasis. 相似文献
477.
Johana Vsquez-Procopio Johnatan Torres-Torres Hector Borboa-Olivares Salvador Espino Y Sosa Raigam Jafet Martínez-Portilla Mario Solis-Paredes Mari-Cruz Tolentino-Dolores Addy Cecilia Helguera-Repetto Karla Cecilia Marrufo-Gallegos Fanis Missirlis Otilia Perichart-Perera Guadalupe Estrada-Gutierrez 《International journal of molecular sciences》2022,23(23)
Evidence from studies in the general population suggests an association between vitamin D insufficiency/deficiency and COVID-19 susceptibility and disease severity. The present study was performed on 165 third-trimester pregnant women at the time of delivery. Seventy-nine women tested negative for SARS-CoV-2. From 86 women testing positive, 32 were asymptomatic, 44 presented a mild form of the disease, and 10 experienced severe symptoms. Serum 25-OH vitamin D levels were measured on blood samples collected on admission. Low vitamin D levels were detected in symptomatic but not asymptomatic COVID-19 patients compared to healthy women (p = 0.0227). In addition, 20 (45.4%) pregnant women in the mild COVID-19 group and 6 (60%) in the severe group were vitamin D deficient (p = 0.030). On the other hand, lasso regression analysis showed that 25-OH vitamin D deficiency is an independent predictor of severe COVID-19 with an odds ratio (OR) of 5.81 (95% CI: 1.108–30.541; p = 0.037). These results show the relationship between vitamin D deficiency in pregnant women and the severity of COVID-19 infection and support the recommendation to supplement with vitamin D to avoid worse COVID-19 outcomes during pregnancy. 相似文献
478.
Jose Fernando Garcia Tirado Alejandro Marquez‐Ruiz Hector Botero Castro Fabiola Angulo 《国际强度与非线性控制杂志
》2018,28(1):326-341
》2018,28(1):326-341
This paper addresses the problem of estimating the state for a class of uncertain discrete‐time linear systems with constraints by using an optimization‐based approach. The proposed scheme uses the moving horizon estimation philosophy together with the game theoretical approach to the filtering to obtain a robust filter with constraint handling. The used approach is constructive since the proposed moving horizon estimator (MHE) results from an approximation of a type of full information estimator for uncertain discrete‐time linear systems, named in short ‐MHE and –full information estimator, respectively. Sufficient conditions for the stability of the ‐MHE are discussed for a class of uncertain discrete‐time linear systems with constraints. Finally, since the ‐MHE needs the solution of a complex minimax optimization problem at each sampling time, we propose an approximation to relax the optimization problem and hence to obtain a feasible numerical solution of the proposed filter. Simulation results show the effectiveness of the robust filter proposed. 相似文献
479.
Hugo Casquero Lei Liu Carles Bona‐Casas Yongjie Zhang Hector Gomez 《International journal for numerical methods in engineering》2016,105(11):855-880
We present a hybrid variational‐collocation, immersed, and fully‐implicit formulation for fluid‐structure interaction (FSI) using unstructured T‐splines. In our immersed methodology, we define an Eulerian mesh on the whole computational domain and a Lagrangian mesh on the solid domain, which moves arbitrarily on top of the Eulerian mesh. Mathematically, the problem reduces to solving three equations, namely, the linear momentum balance, mass conservation, and a condition of kinematic compatibility between the Lagrangian displacement and the Eulerian velocity. We use a weighted residual approach for the linear momentum and mass conservation equations, but we discretize directly the strong form of the kinematic relation, deriving a hybrid variational‐collocation method. We use T‐splines for both the spatial discretization and the information transfer between the Eulerian mesh and the Lagrangian mesh. T‐splines offer us two main advantages against non‐uniform rational B‐splines: they can be locally refined and they are unstructured. The generalized‐α method is used for the time discretization. We validate our formulation with a common FSI benchmark problem achieving excellent agreement with the theoretical solution. An example involving a partially immersed solid is also solved. The numerical examples show how the use of T‐junctions and extraordinary nodes results in an accurate, efficient, and flexible method. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
480.