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1.
Nanomaterials (Basel) ; 14(3)2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38334548

RESUMO

The primary objective of this research was to develop efficient solid catalysts that can directly convert the lactic acid (LA) obtained from lignocellulosic biomass into alanine (AL) through a reductive amination process. To achieve this, various catalysts based on ruthenium were synthesized using different carriers such as multi-walled carbon nanotubes (MWCNTs), beta-zeolite, and magnetic nanoparticles (MNPs). Among these catalysts, Ru/MNP demonstrated a remarkable yield of 74.0% for alanine at a temperature of 200 °C. This yield was found to be superior not only to the Ru/CNT (55.7%) and Ru/BEA (6.6%) catalysts but also to most of the previously reported catalysts. The characterization of the catalysts and their catalytic results revealed that metallic ruthenium nanoparticles, which were highly dispersed on the external surface of the magnetic carrier, significantly enhanced the catalyst's ability for dehydrogenation. Additionally, the -NH2 basic sites on the catalyst further facilitated the formation of alanine by promoting the adsorption of acidic reactants. Furthermore, the catalyst could be easily separated using an external magnetic field and exhibited the potential for multiple reuses without any significant loss in its catalytic performance. These practical advantages further enhance its appeal for applications in the reductive amination of lactic acid to alanine.

2.
Bioengineering (Basel) ; 11(1)2024 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-38247956

RESUMO

The end of 2019 could be mounted in a rudimentary framing of a new medical problem, which globally introduces into the discussion a fulminant outbreak of coronavirus, consequently spreading COVID-19 that conducted long-lived and persistent repercussions. Hence, the theme proposed to be solved arises from the field of medical imaging, where a pulmonary CT-based standardized reporting system could be addressed as a solution. The core of it focuses on certain impediments such as the overworking of doctors, aiming essentially to solve a classification problem using deep learning techniques, namely, if a patient suffers from COVID-19, viral pneumonia, or is healthy from a pulmonary point of view. The methodology's approach was a meticulous one, denoting an empirical character in which the initial stage, given using data processing, performs an extraction of the lung cavity from the CT scans, which is a less explored approach, followed by data augmentation. The next step is comprehended by developing a CNN in two scenarios, one in which there is a binary classification (COVID and non-COVID patients), and the other one is represented by a three-class classification. Moreover, viral pneumonia is addressed. To obtain an efficient version, architectural changes were gradually made, involving four databases during this process. Furthermore, given the availability of pre-trained models, the transfer learning technique was employed by incorporating the linear classifier from our own convolutional network into an existing model, with the result being much more promising. The experimentation encompassed several models including MobileNetV1, ResNet50, DenseNet201, VGG16, and VGG19. Through a more in-depth analysis, using the CAM technique, MobilneNetV1 differentiated itself via the detection accuracy of possible pulmonary anomalies. Interestingly, this model stood out as not being among the most used in the literature. As a result, the following values of evaluation metrics were reached: loss (0.0751), accuracy (0.9744), precision (0.9758), recall (0.9742), AUC (0.9902), and F1 score (0.9750), from 1161 samples allocated for each of the three individual classes.

3.
J Clin Med ; 12(1)2022 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-36615027

RESUMO

BACKGROUND: The left circumflex coronary artery from the pulmonary artery is a very rare congenital anomaly with few cases described, so far, worldwide. CASE REPORT: An 81-year-old female presented complaining of dyspnea. The transthoracic echocardiogram revealed severe degenerative aortic stenosis in addition to a hypertrophied left ventricle with normal function and no wall motion abnormalities. As part of the pre-TAVI planning, she underwent a CT examination, which revealed an anomalous left circumflex artery originating from the right pulmonary artery. The case is currently being managed conservatively. CONCLUSION: The presented congenital coronary anomaly is, to our knowledge, the first to be described in the literature in this age group (80+).

4.
BMC Med Inform Decis Mak ; 21(1): 274, 2021 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-34600518

RESUMO

BACKGROUND: Artificial intelligence (AI) has the potential to transform our healthcare systems significantly. New AI technologies based on machine learning approaches should play a key role in clinical decision-making in the future. However, their implementation in health care settings remains limited, mostly due to a lack of robust validation procedures. There is a need to develop reliable assessment frameworks for the clinical validation of AI. We present here an approach for assessing AI for predicting treatment response in triple-negative breast cancer (TNBC), using real-world data and molecular -omics data from clinical data warehouses and biobanks. METHODS: The European "ITFoC (Information Technology for the Future Of Cancer)" consortium designed a framework for the clinical validation of AI technologies for predicting treatment response in oncology. RESULTS: This framework is based on seven key steps specifying: (1) the intended use of AI, (2) the target population, (3) the timing of AI evaluation, (4) the datasets used for evaluation, (5) the procedures used for ensuring data safety (including data quality, privacy and security), (6) the metrics used for measuring performance, and (7) the procedures used to ensure that the AI is explainable. This framework forms the basis of a validation platform that we are building for the "ITFoC Challenge". This community-wide competition will make it possible to assess and compare AI algorithms for predicting the response to TNBC treatments with external real-world datasets. CONCLUSIONS: The predictive performance and safety of AI technologies must be assessed in a robust, unbiased and transparent manner before their implementation in healthcare settings. We believe that the consideration of the ITFoC consortium will contribute to the safe transfer and implementation of AI in clinical settings, in the context of precision oncology and personalized care.


Assuntos
Inteligência Artificial , Neoplasias , Algoritmos , Humanos , Aprendizado de Máquina , Medicina de Precisão
5.
Molecules ; 25(21)2020 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-33105761

RESUMO

Nb(0.05 moles%)-zeolites prepared via a post synthesis methodology (BEA, Y, ZSM-5), or a direct sol-gel method (Silicalite-1) were investigated in the hydroxymethylfurfural (HMF) oxidation by both molecular oxygen, in aqueous phase, and organic peroxides, in acetonitrile. The catalysts prepared through the post synthesis methodology (i.e., Nb-Y5, Nb-ZSM25, Nb-Y30, Nb-BEA12, and Nb-BEA18) displayed a mono-modal mesoporosity and contain residual framework Al-acid sites, extra framework isolated Nb(V)O-H and Nb2O5 pore-encapsulated clusters, while Nb-Sil-1, prepared through a direct synthesis procedure, displayed a bimodal micro-mesoporosity and contains only -Nb=O species. These modified zeolites behave as efficient catalysts in both HMF/glucose wet oxidation to succinic acid (SA) and HMF oxidation with organic peroxides to the 2,5-furandicarboxylic acid (FDCA). The catalytic behavior of these catalysts, in terms of conversion and especially the selectivity, mainly depended on the base/acid sites ratio. Thus, the HMF/glucose wet oxidation occurred with a total conversion and a selectivity to SA of 37.7% (from HMF) or 69.1% (from glucose) on the Nb-Y5 catalyst, i.e., the one with the lowest base/acid sites ratio. On the contrary, the catalysts with the highest base/acid sites ratio, i.e., Nb-ZSM25 and Nb-Sil-1, afforded a high catalytic efficiency in HMF oxidation with organic peroxides, in which FDCA was produced with selectivities of 61.3-63.8% for an HMF conversion of 96.7-99.0%.


Assuntos
Ácidos Dicarboxílicos/síntese química , Furanos/síntese química , Nióbio/química , Óxidos/química , Ácido Succínico/síntese química , Zeolitas/química , Adsorção , Catálise , Furaldeído/análogos & derivados , Furaldeído/química , Glucose/química , Nitrogênio/química , Oxirredução , Oxigênio/química , Peróxidos/química , Porosidade
6.
Chem Soc Rev ; 47(22): 8349-8402, 2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-30226518

RESUMO

Efficient transformation of biomass to value-added chemicals and high-energy density fuels is pivotal for a more sustainable economy and carbon-neutral society. In this framework, developing potential cascade chemical processes using functionalised heterogeneous catalysts is essential because of their versatile roles towards viable biomass valorisation. Advances in materials science and catalysis have provided several innovative strategies for the design of new appealing catalytic materials with well-defined structures and special characteristics. Promising catalytic materials that have paved the way for exciting scientific breakthroughs in biomass upgrading are carbon materials, metal-organic frameworks, solid phase ionic liquids, and magnetic iron oxides. These fascinating catalysts offer unique possibilities to accommodate adequate amounts of acid-base and redox functional species, hence enabling various biomass conversion reactions in a one-pot way. This review therefore aims to provide a comprehensive account of the most significant advances in the development of functionalised heterogeneous catalysts for efficient biomass upgrading. In addition, this review highlights important progress ensued in tailoring the immobilisation of desirable functional groups on particular sites of the above-listed materials, while critically discussing the role of consequent properties on cascade reactions as well as on other vital processes within the bio-refinery. Current challenges and future opportunities towards a rational design of novel functionalised heterogeneous catalysts for sustainable biomass valorisation are also emphasized.

7.
Molecules ; 22(12)2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29240713

RESUMO

The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%)-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V) and Nb2O5 pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA) which, further, suffers an oxidation process to succinic acid (SA). After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O2, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.


Assuntos
Glucose/química , Nióbio/química , Ácido Succínico/síntese química , Zeolitas/química , Sítios de Ligação , Catálise , Oxirredução , Porosidade , Solventes/química , Propriedades de Superfície , Água
8.
Chem Commun (Camb) ; 53(74): 10271-10274, 2017 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-28862277

RESUMO

Modification of GO by organic molecules changes its catalytic activity in the hydrogen transfer from i-propanol to enones, affecting the selectivity to allyl alcohol and diastereoselectivity to the resulting stereoisomers. It is noteworthy the system does not contain metals and is recyclable.


Assuntos
Grafite/química , Óxidos/química , Prostaglandinas/síntese química , Catálise , Hidrogenação , Estrutura Molecular , Prostaglandinas/química , Estereoisomerismo
9.
ChemSusChem ; 9(17): 2307-11, 2016 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-27511900

RESUMO

A new pathway for the catalytic wet oxidation (CWO) of glucose is described. Employing a cationic Ru@MNP catalyst, succinic acid is obtained in unprecedently high yield (87.5 %) for a >99.9 % conversion of glucose, most probably through a free radical mechanism combined with catalytic didehydroxylation of vicinal diols and hydrogenation of the resulted unsaturated intermediate.


Assuntos
Butilaminas/química , Glucose/química , Rutênio/química , Ácido Succínico/química , Catálise , Oxirredução
10.
Angew Chem Int Ed Engl ; 55(2): 607-12, 2016 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-26597312

RESUMO

Pyrolysis of chitosan films containing Au(3+) renders 1.1.1 oriented Au nanoplatelets (20 nm lateral size, 3-4 nm height) on a few layers of N-doped graphene (Au/fl-G), while the lateral sides were 0.0.1 oriented. Comparison of the catalytic activity of Au/fl-G films with powders of unoriented Au NPs supported on graphene showed that Au/fl-G films exhibit six orders of magnitude enhancement for three gold-catalyzed reactions, namely, Ullmann-like homocoupling, C-N cross coupling, and the oxidative coupling of benzene to benzoic acid. This enhancement is the result of the defined morphology, facet orientation of Au nanocrystals, and strong gold-graphene interaction.

11.
Curr Pharm Des ; 21(38): 5558-72, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26553252

RESUMO

A major trend in fine chemicals and pharmaceuticals is the synthesis of molecules with increased complexity. This trend translates the aim of organic syntheses to conditions in which high degrees of chemo-, regio- and stereoselectivity can be provided. In this context, the chemoselective hydrogenation of one functional group in the presence of other reactive groups is a frequently encountered problem in fine chemicals manufacture. This study provides a critical analysis including elegant examples of reactions in which high chemo- and diastereoselectivities were achieved in the hydrogenation of a C=O group in the presence of C=C double bond. A particular emphasis is addressed to the stereoselective C(15) synthesis from Cloprostenol--a PGF2α structural analogue.


Assuntos
Dinoprosta/análogos & derivados , Dinoprosta/metabolismo , Animais , Catálise , Dinoprosta/química , Humanos , Hidrogenação , Estrutura Molecular , Estereoisomerismo
12.
Nat Commun ; 6: 8561, 2015 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-26509224

RESUMO

Metal oxide nanoparticles supported on graphene exhibit high catalytic activity for oxidation, reduction and coupling reactions. Here we show that pyrolysis at 900 °C under inert atmosphere of copper(II) nitrate embedded in chitosan films affords 1.1.1 facet-oriented copper nanoplatelets supported on few-layered graphene. Oriented (1.1.1) copper nanoplatelets on graphene undergo spontaneous oxidation to render oriented (2.0.0) copper(I) oxide nanoplatelets on few-layered graphene. These films containing oriented copper(I) oxide exhibit as catalyst turnover numbers that can be three orders of magnitude higher for the Ullmann-type coupling, dehydrogenative coupling of dimethylphenylsilane with n-butanol and C-N cross-coupling than those of analogous unoriented graphene-supported copper(I) oxide nanoplatelets.

13.
ChemSusChem ; 6(11): 2090-4, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24108509

RESUMO

A sweet catalyst: A catalyst formed of Ru/functionalized silica-coated magnetite nanoparticles is highly efficient in the one-pot production of sorbitol and glycerol, starting from cellulose and in the absence of an external hydrogen source. The ease of recoverability of the catalyst from the solid residues, and its reuse without loss of activity or selectivity for several runs, is an important green element of the process.


Assuntos
Celulose/química , Glicerol/síntese química , Nanopartículas de Magnetita/química , Rutênio/química , Sorbitol/síntese química , Técnicas de Química Sintética , Temperatura
14.
ChemSusChem ; 5(9): 1708-11, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22890984

RESUMO

TIN, TAILORED, NOT SOLDER, BUT CAT: Doped hydroxylated fluorides, prepared by a modified sol-gel method, offer enhanced acidity and improved stability against water, and efficiency in the degradation of cellulose. These materials extend the portfolio of acid catalysts for fast and selective hydrolysis of biomass to glucose, which offers a feedstock for bioethanol production.


Assuntos
Celulose/química , Fluoretos/química , Glucose/química , Compostos de Magnésio/química , Estanho/química , Catálise , Hidroxilação , Cinética , Especificidade por Substrato
16.
Chem Commun (Camb) ; (4): 460-2, 2009 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-19137185

RESUMO

Based on a fluorolytic sol-gel synthesis, nanoscopic metal fluorides and partly hydroxylated metal fluorides were synthesized; varying the F : OH ratio inside these solids yielded catalysts with different combinations and variable strength Lewis and Brønsted acid sites, which demonstrated unexpected catalytic properties for the diastereoselective synthesis of (+/-)-isopulegol.


Assuntos
Aldeídos/química , Fluoretos/química , Monoterpenos/química , Terpenos/síntese química , Monoterpenos Acíclicos , Catálise , Monoterpenos Cicloexânicos , Estereoisomerismo
17.
Chemistry ; 14(36): 11488-99, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19006145

RESUMO

Novel magnesium fluorides have been prepared by a new fluorolytic sol-gel synthesis for fluoride materials based on aqueous HF. By changing the amount of water at constant stoichiometric amount of HF, it is possible to tune the surface acidity of the resulting partly hydroxylated magnesium fluorides. These materials possess medium-strength Lewis acid sites and, by increasing the amount of water, Brønsted acid sites as well. Magnesium hydroxyl groups normally have a basic nature and only with this new synthetic route is it possible to create Brønsted acidic magnesium hydroxyl groups. XRD, MAS NMR, TEM, thermal analysis, and elemental analysis have been applied to study the structure, composition, and thermal behaviour of the bulk materials. XPS measurements, FTIR with probe molecules, and the determination of N(2)/Ar adsorption-desorption isotherms have been carried out to investigate the surface properties. Furthermore, activity data have indicated that the tuning of the acidic properties makes these materials versatile catalysts for different classes of reactions, such as the synthesis of (all-rac)-[alpha]-tocopherol through the condensation of 2,3,6-trimethylhydroquinone (TMHQ) with isophytol (IP).

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