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1.
Molecules ; 26(11)2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073307

RESUMO

The presence of water in the form of relative humidity (RH) may lead to deliquescence of crystalline components above a certain RH, the deliquescence RH (DRH). Knowing the DRH values is essential, e.g., for the agrochemical industry, food industry, and pharmaceutical industry to identify stability windows for their crystalline products. This work applies the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) to purely predict the DRH of single components (organic acids, sugars, artificial sweeteners, and amides) and multicomponent crystal mixtures thereof only based on aqueous solubility data of the pure components. The predicted DRH values very well agree with the experimental ones. In addition, the temperature influence on the DRH value could be successfully predicted with PC-SAFT. The DRH prediction also differentiates between formation of hydrates and anhydrates. PC-SAFT-predicted phase diagrams of hydrate-forming components illustrate the influence of additional components on the hydrate formation as a function of RH. The DRH prediction via PC-SAFT allows for the determining of the stability of crystals and crystal mixtures without the need for time-consuming experiments.


Assuntos
Técnicas de Química Analítica , Química Farmacêutica , Cristalização , Estabilidade de Medicamentos , Indústria Alimentícia , Umidade , Compostos Orgânicos/química , Solubilidade , Açúcares/química , Edulcorantes , Temperatura , Termodinâmica , Água
2.
Ecotoxicol Environ Saf ; 221: 112422, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34144252

RESUMO

Homogeneous Cu2+-mediated activation of H2O2 has been widely applied for the removal of organic contaminants, but fairly high dosage of Cu2+ is generally required and may cause secondary pollution. In the present study, minute Cu2+ (2.5 µM) catalyzed H2O2 exhibited excellent efficiency in degradation of organic pollutants with the assistant of naturally occurring level HCO3- (1 mM). In a typical case, acetaminophen (ACE) was completely eliminated within 10 min which followed the pseudo-first-order kinetics. Singlet oxygen and superoxide radical rather than traditionally identified hydroxyl radical were the predominant reactive oxygen species (ROS) responsible for ACE degradation. Meanwhile, Cu3+ was deduced through Cu+ and p-hydroxybenzoic acid formation analysis. CuCO3(aq) was the main complex with high reactivity for the activation of H2O2 to form ROS and Cu3+. The removal efficiency of ACE depended on the operating parameters, such as Cu2+, HCO3- and H2O2 dosage, solution initial pH. The presence of Cl-, HPO42-, humic acid were found to retard ACE removal while other anions such as SO42- and NO3- had no obvious effect. ACE exhibited lower degradation efficiency in real water matrices than that in ultra-pure water. Nevertheless, 58-100% of ACE was removed from domestic wastewater, lake water and tap water within 60 min. Moreover, eight intermediate products were identified and the possible degradation pathways of ACE were proposed. Additionally, other typical organic pollutants including bisphenol A, norfloxacin, lomefloxacin hydrochloride and sulfadiazine, exhibited great removal efficiency in the Cu2+/H2O2/HCO3- system.


Assuntos
Acetaminofen/química , Bicarbonatos/química , Cobre/química , Peróxido de Hidrogênio/química , Espécies Reativas de Oxigênio/química , Poluentes Químicos da Água/química , Catálise , Compostos Orgânicos/química , Purificação da Água/métodos
3.
Molecules ; 26(9)2021 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-34065150

RESUMO

Bioanalysis is the scientific field of the quantitative determination of xenobiotics (e.g., drugs and their metabolites) and biotics (e.g., macromolecules) in biological matrices. The most common samples in bioanalysis include blood (i.e., serum, plasma and whole blood) and urine. However, the analysis of alternative biosamples, such as hair and nails are gaining more and more attention. The main limitations for the determination of small organic compounds in biological samples is their low concentration in these matrices, in combination with the sample complexity. Therefore, a sample preparation/analyte preconcentration step is typically required. Currently, the development of novel microextraction and miniaturized extraction techniques, as well as novel adsorbents for the analysis of biosamples, in compliance with the requirements of Green Analytical Chemistry, is in the forefront of research in analytical chemistry. Graphene oxide (GO) is undoubtedly a powerful adsorbent for sample preparation that has been successfully coupled with a plethora of green extraction techniques. GO is composed of carbon atoms in a sp2 single-atom layer of a hybrid connection, and it exhibits high surface area, as well as good mechanical and thermal stability. In this review, we aim to discuss the applications of GO and functionalized GO derivatives in microextraction and miniaturized extraction techniques for the determination of small organic molecules in biological samples.


Assuntos
Grafite/química , Química Verde , Compostos Orgânicos/química , Extração em Fase Sólida/métodos , Adsorção , Carbono/química , Humanos , Magnetismo , Polímeros Molecularmente Impressos , Nanomedicina , Nanoestruturas , Reprodutibilidade dos Testes , Propriedades de Superfície
4.
J Food Sci ; 86(7): 2785-2801, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34160057

RESUMO

This review discusses the application of oleogel technology in emulsified systems. In these systems of mimetic fats, water-in-oil or oil-in-water emulsions can be obtained, but, here, we cover emulsions with an oil continuous phase in detail. Depending on the percentage of water added to the oleogels, systems with different textures and rheological properties can be developed. These properties are affected by the characteristics and concentration of the added components and emulsion preparation methods. In addition, some gelators exhibit interfacial properties, resulting in more stable emulsions than those of conventional emulsions. Oleogel-based emulsion are differentiated by continuous and dispersed phases and the structuring/emulsification components. Crucially, these emulsions could be applied by the food industry for preparing, for example, meat products and margarines, as well as by the cosmetics industry. We present the different processes of emulsion elaboration, the main gelators used, the influence of the water content on the structuring of water-in-oleogel emulsions, and the structuring mechanisms (Pickering, network, and combined Pickering and network stabilization). Finally, we highlight the applications of these systems as alternatives for reducing processed food lipid content and saturated fat levels.


Assuntos
Emulsões , Ácidos Graxos/análise , Margarina/análise , Produtos da Carne/análise , Reologia , Compostos Orgânicos/química
5.
Int J Mol Sci ; 22(11)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067406

RESUMO

The use of reactive electrochemical membranes (REM) in flow-through mode during the anodic oxidation of organic compounds makes it possible to overcome the limitations of plate anodes: in the case of REM, the area of the electrochemically active surface is several orders of magnitude larger, and the delivery of organic compounds to the reaction zone is controlled by convective flow rather than diffusion. The main problem with REM is the formation of fouling and gas bubbles in the pores, which leads to a decrease in the efficiency of the process because the hydraulic resistance increases and the electrochemically active surface is shielded. This work aims to study the processes underlying the reduction in the efficiency of anodic oxidation, and in particular the formation of gas bubbles and the recharge of the REM pore surface at a current density exceeding the limiting kinetic value. We propose a simple one-dimensional non-stationary model of the transport of diluted species during the anodic oxidation of paracetamol using REM to describe the above effects. The processing of the experimental data was carried out. It was found that the absolute value of the zeta potential of the pore surface decreases with time, which leads to a decrease in the permeate flux due to a reduction in the electroosmotic flow. It was shown that in the solution that does not contain organic components, gas bubbles form faster and occupy a larger pore fraction than in the case of the presence of paracetamol; with an increase in the paracetamol concentration, the gas fraction decreases. This behavior is due to a decrease in the generation of oxygen during the recombination reaction of the hydroxyl radicals, which are consumed in the oxidation reaction of the organic compounds. Because the presence of bubbles increases the hydraulic resistance, the residence time of paracetamol-and consequently its degradation degree-increases, but the productivity goes down. The model has predictive power and, after simple calibration, can be used to predict the performance of REM anodic oxidation systems.


Assuntos
Gases/química , Compostos Orgânicos/química , Eletrodos , Radical Hidroxila/química , Membranas Artificiais , Oxirredução , Poluentes Químicos da Água/química
6.
Molecules ; 26(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067007

RESUMO

As film-forming agents, fillers and adsorbents, microplastics are often added to daily personal care products. Because of their chemical stability, they remain in the environment for thousands of years, endangering the safety of the environment and human health. Therefore, it is urgent to find an environmentally friendly substitute for microplastics. Using n-octyltrimethoxysilane (OTMS) and tetraethoxysilane (TEOS) as silicon sources, a novel, environmentally friendly, organic hollow mesoporous silica system is designed with a high loading capacity and excellent adsorption characteristics in this work. In our methodology, sandalwood essential oil (SEO) was successfully loaded into the nanoparticle cavities, and was involved in the formation of Pickering emulsion as well, with a content of up to 40% (w/w). The developed system was a stable carrier for the dispersion of SEO in water. This system can not only overcome the shortcomings of poor water solubility and volatility of sandalwood essential oil, but also act as a microplastic substitute with broad prospects in the cosmetics and personal care industry, laying a foundation for the preparation and applications of high loading capacity microcapsules in aqueous media.


Assuntos
Portadores de Fármacos/química , Óleos Voláteis/química , Compostos Orgânicos/química , Óleos Vegetais/química , Sesquiterpenos/química , Dióxido de Silício/química , Cápsulas , Emulsões , Espectroscopia Fotoeletrônica , Porosidade , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Vibração , Água/química
7.
Food Chem ; 360: 130017, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33984566

RESUMO

With an aim to prepare the functional chocolate, corn oil was used as the base oil and ß-sitosterol was combined with oryzanol/stearic acid/lecithin to prepare respective oleogels (GO, SO, and LO). Oleogels (12%) were prepared by adding compound oleogelators at different ratios [GO-2:3, SO-1:4, and LO-4:1 (w/w)] in corn oil. The microstructure, interaction, thermodynamic, crystalline, and rheological behavior of formulated oleogels were studied by microscopic observation, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and rotational rheometer, respectively. The results showed that GO had the strongest gel forming ability and the densest gel crystallization network. Moreover, chocolate prepared with GO (cocoa butter and oleogels-1:1) had the similar texture, crystal structure, rheological, and sensory properties to that of dark chocolate. This study provides the possibility for the wider application of oleogel prepared with lower saturated and trans-fatty acids in the chocolate industry.


Assuntos
Chocolate , Lecitinas/química , Ácidos Esteáricos/química , Varredura Diferencial de Calorimetria , Cristalização , Compostos Orgânicos/química , Reologia , Difração de Raios X
8.
Ecotoxicol Environ Saf ; 220: 112315, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34015628

RESUMO

Particulate organic matter (POM) is an effective adsorbent for decreasing the contaminant of cadmium, but little is known about the relevant mechanisms under the effect of plant. In this work, POM were used to study the removal of Cd2+ in the initial concentration range of 0-4.46 mmol L-1 at pH 5.5, and the effect of Artemisia ordosica roots and pH on kinetics and equilibrium of cadmium adsorption on POM and soils were examined. The result indicated that adsorption kinetics fit well with the pseudo-second-order kinetic model, and the equilibrium data for Cd adsorption fit much well to the Langmuir model. The maximum adsorption capacity for POM at equilibrium corresponding to the monolayer coverage reached 0.287 mmol/g for Cd. The amount of Cd adsorbed in the POM and soil increased with the increase of pH from 4 to 8.5. The Artemisia ordosica roots decreased Cd adsorption in POM; instead, the adsorption capacity of soil for Cd was improved under the effect of Artemisia ordosica roots. The Fourier Transform Infrared spectroscopic (FTIR) analysis indicated that the complexation of POM and Cd was mainly through sulfhydryl, hydroxyl and carboxyl groups.


Assuntos
Artemisia/metabolismo , Cádmio/metabolismo , Material Particulado/química , Raízes de Plantas/metabolismo , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Solo/química , Adsorção , Compostos Orgânicos/química
9.
Food Chem ; 359: 129935, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33934032

RESUMO

To understand the specific contributions of amorphous sugars and organic acids to the quality of food matrix, the solid model system of jujube slice skeleton (JSS) was firstly established. Effects of fructose (F), glucose (G), malic acid (M) and citric acid (C) on the glass transition temperature (Tg) and crystallization of JSS were studied. JSS-F/G/M/C blends were prepared by osmosis in the solution at a range of 0 ~ 32 g/100 g. Sugars reduced the Tg in the system, structure of JSS-G/M blends was changed from "amorphous glassy" to "amorphous rubbery" by increasing the osmotic solute concentration. Tg was decreased from 50.8 to 14.0 °C when JSS was osmosed in a 4 g/100 g fructose solution. Organic acids induced their crystallization in JSS. The crystallinity of JSS-M immersed in 32 g/100 g osmotic solution concentration was increased from 2% to 75%. Fructose presented greater influence on the adverse quality of jujube slices.


Assuntos
Ácidos/química , Compostos Orgânicos/química , Açúcares/química , Temperatura de Transição , Vitrificação , Ziziphus/química , Varredura Diferencial de Calorimetria , Cristalização , Vidro/química , Temperatura , Água/química
10.
Nucleic Acids Res ; 49(9): 5143-5158, 2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-33905507

RESUMO

SYBR Gold is a commonly used and particularly bright fluorescent DNA stain, however, its chemical structure is unknown and its binding mode to DNA remains controversial. Here, we solve the structure of SYBR Gold by NMR and mass spectrometry to be [2-[N-(3-dimethylaminopropyl)-N-propylamino]-4-[2,3-dihydro-3-methyl-(benzo-1,3-thiazol-2-yl)-methylidene]-1-phenyl-quinolinium] and determine its extinction coefficient. We quantitate SYBR Gold binding to DNA using two complementary approaches. First, we use single-molecule magnetic tweezers (MT) to determine the effects of SYBR Gold binding on DNA length and twist. The MT assay reveals systematic lengthening and unwinding of DNA by 19.1° ± 0.7° per molecule upon binding, consistent with intercalation, similar to the related dye SYBR Green I. We complement the MT data with spectroscopic characterization of SYBR Gold. The data are well described by a global binding model for dye concentrations ≤2.5 µM, with parameters that quantitatively agree with the MT results. The fluorescence increases linearly with the number of intercalated SYBR Gold molecules up to dye concentrations of ∼2.5 µM, where quenching and inner filter effects become relevant. In summary, we provide a mechanistic understanding of DNA-SYBR Gold interactions and present practical guidelines for optimal DNA detection and quantitative DNA sensing applications using SYBR Gold.


Assuntos
DNA/análise , Corantes Fluorescentes/química , Compostos Orgânicos/química , Benzotiazóis/química , DNA/química , Diaminas/química , Estrutura Molecular , Quinolinas/química
11.
J Ind Microbiol Biotechnol ; 48(1-2)2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33928348

RESUMO

Saline wastewater contaminated with aromatic compounds can be frequently found in various industrial sectors. Those compounds need to be degraded before reuse of wastewater in other process steps or release to the environment. Halophiles have been reported to efficiently degrade aromatics, but their application to treat industrial wastewater is rare. Halophilic processes for industrial wastewater treatment need to satisfy certain requirements: a continuous process mode, low operational expenditures, suitable reactor systems and a monitoring and control strategy. The aim of this review is to provide an overview of halophilic microorganisms, principles of aromatic biodegradation, and sources of saline wastewater containing aromatics and other contaminants. Finally, process examples for halophilic wastewater treatment and potential process monitoring strategies are discussed. To further illustrate the significant potential of halophiles for saline wastewater treatment and to facilitate development of ready-to-implement processes, future research should focus on scale-up and innovative process monitoring and control strategies.


Assuntos
Compostos Orgânicos/metabolismo , Águas Residuárias/química , Biodegradação Ambiental , Compostos Orgânicos/química , Purificação da Água
12.
Nat Commun ; 12(1): 2466, 2021 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-33927199

RESUMO

Microorganisms play vital roles in modulating organic matter decomposition and nutrient cycling in soil ecosystems. The enzyme latch paradigm posits microbial degradation of polyphenols is hindered in anoxic peat leading to polyphenol accumulation, and consequently diminished microbial activity. This model assumes that polyphenols are microbially unavailable under anoxia, a supposition that has not been thoroughly investigated in any soil type. Here, we use anoxic soil reactors amended with and without a chemically defined polyphenol to test this hypothesis, employing metabolomics and genome-resolved metaproteomics to interrogate soil microbial polyphenol metabolism. Challenging the idea that polyphenols are not bioavailable under anoxia, we provide metabolite evidence that polyphenols are depolymerized, resulting in monomer accumulation, followed by the generation of small phenolic degradation products. Further, we show that soil microbiome function is maintained, and possibly enhanced, with polyphenol addition. In summary, this study provides chemical and enzymatic evidence that some soil microbiota can degrade polyphenols under anoxia and subvert the assumed polyphenol lock on soil microbial metabolism.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Compostos Orgânicos/metabolismo , Polifenóis/metabolismo , Poluentes do Solo/metabolismo , Anaerobiose , Reatores Biológicos/microbiologia , Microbiota/fisiologia , Compostos Orgânicos/química , Solo/química , Microbiologia do Solo , Áreas Alagadas
13.
Molecules ; 26(6)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802773

RESUMO

Oleogels or, more precisely, non-triglyceride structured lipid phases have been researched excessively in the last decade. Yet, no comprehensive knowledge base has emerged, allowing technology elevation from the laboratory bench into the industrial food application. That is partly due to insufficient characterization of the structuring systems studied. Examining a single composition decided upon by arbitrary methods does not stimulate progress in the research and technology area. A framework that gives much better guidance to product applications can easily be derived. For example, the incremental structure contribution concept is advocated as a parameter to compare the potency of structuring systems. These can straightforwardly be determined by combining solubility data and structural measurements in the recommended manner. The current method to determine the oil-binding capacity suffers from reproducibility and relevance. A newly developed method is suggested to overcome these shortcomings. The recommended new characterization of oleogels should contribute to a more comprehensive knowledge base necessary for product innovations.


Assuntos
Tecnologia de Alimentos/métodos , Varredura Diferencial de Calorimetria , Microscopia Crioeletrônica , Cristalização , Emulsões/química , Microscopia de Força Atômica , Óleos/química , Compostos Orgânicos/química , Reprodutibilidade dos Testes , Solubilidade , Temperatura , Água/química
14.
Food Chem ; 356: 129703, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33848680

RESUMO

Cold plasma as a green and expeditious tool was used to modify whey protein isolate (WPI) in order to improve its emulsion capability. The emulsion-based oleogels with antibacterial functions were then constructed using the modified WPI. The modified WPI treated with cold plasma under 10 s at 50 W power significantly lowered the oil-water interface tension. Meanwhile, the fluorescence intensity and the α-helix content of WPI reduced with the cold plasma treatment. It is noted that SEM results showed that the treated WPI had more regular dendritic structures. Such modified WPI was applied to construct oleogels loaded with thyme essential oil and coconut oil, which showed a porous uniform network structure and excellent antimicrobial activities against E.coli. As a proof of concept, this study demonstrated cold plasma could be as a new facile tool to modify food-sourced proteins and expected to enlarge their applications in oleogel productions.


Assuntos
Emulsões/química , Gases em Plasma/química , Proteínas do Soro do Leite/química , Escherichia coli/efeitos dos fármacos , Óleos/química , Compostos Orgânicos/química , Compostos Orgânicos/farmacologia , Conformação Proteica em alfa-Hélice , Reologia , Staphylococcus aureus/efeitos dos fármacos , Tensão Superficial , Viscosidade , Água/química
15.
Molecules ; 26(8)2021 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-33921789

RESUMO

The zinc dithiocarbamates functionalized with folic acid 2Zn and 3Zn were synthesized with a simple straightforward method, using an appropriated folic acid derivative and a functionalized zinc dithiocarbamate (1Zn). Zinc complexes 2Zn and 3Zn show very low solubilities in water, making them useful for preparing Tc-99m radiopharmaceuticals with a potentially high molar activity. Thus, the transmetallation reaction in water medium between the zinc complexes 2Zn or 3Zn and the cation fac-[99mTc(H2O)3(CO)3]+, in the presence of the monodentate ligand TPPTS, leads to the formation of the 2 + 1 complexes fac-[99mTc(CO)3(SS)(P)] bioconjugated to folic acid (2Tc and 3Tc). In spite of the low solubility of 2Zn and 3Zn in water, the reaction yield is higher than 95%, and the excess zinc reagent is easily removed by centrifugation. The Tc-99m complexes were characterized by comparing their HPLC with those of the homologous rhenium complexes (2Re and 3Re) previously synthesized and characterized by standard methods. Preliminary in vivo studies with 2Tc and 3Tc indicate low specific binding to folate receptors. In summary, Tc-99m folates 2Tc and 3Tc were prepared in high yields, using a one-pot transmetallation reaction with low soluble zinc dithiocarbamates (>1 ppm), at moderate temperature, without needing a subsequent purification step.


Assuntos
Compostos Orgânicos/química , Compostos Orgânicos/síntese química , Rênio/química , Tecnécio/química , Zinco/química , Ácido Fólico/química , Estrutura Molecular
16.
Food Chem ; 356: 129667, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33831829

RESUMO

In this paper, different types of oleogels were prepared by five gelators including hydroxypropyl methyl cellulose (HPMC), monoacylglycerol (MAG), sodium stearyl lactate (SSL), rice bran wax (RBW) and beeswax (BW), and their applications in cookies were compared. Texture, microstructure, and colour results showed that MAG, RBW and shortening based cookies had similar hardness, porous structure, and L*, a*, b*. MAG and RBW exhibited excellent rheological properties similar to shortening. Regarding the consumer sensory evaluation of cookies, RBW, MAG and shortening had similar scores of 3.9, 4.3 and 4.1, respectively. For wax-based oleogels, the higher the content of ß' crystal and solid fat content (SFC), the lower the hardness of cookies, but the cookies hardness of emulsifier based oleogels do not depend on ß' content and SFC. This paper confirmed the best gelators for cookies, and provided a reference for developing the oleogels to match the quality of shortening in cookies.


Assuntos
Doces/análise , Varredura Diferencial de Calorimetria , Culinária/métodos , Dureza , Derivados da Hipromelose/química , Monoglicerídeos/química , Compostos Orgânicos/química , Reologia , Estearatos/química , Ceras/química
17.
Molecules ; 26(7)2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33917296

RESUMO

INTRODUCTION: Despite the constant efforts of scientists to improve the texture, sensory properties, and nutritional value of gluten-free bread, obtaining high bioavailability of minerals is still a huge challenge. Gluten-free bakery products are characterized by a low bioavailability of minerals. The aim of this study was to design gluten-free bread with high bioavailability of minerals commonly found in deficiencies in people struggling with gluten intolerance. MATERIAL AND METHODS: The material consisted of gluten-free breads designed to obtain the highest possible content of minerals in the bread while maintaining a good structure and taste. RESULTS: Higher contents of all the analyzed minerals were obtained in breads with natural and synthetic additives, both in rice and buckwheat bread, compared to basic bread. There was also a higher content of the analyzed minerals in buckwheat bread in comparison to rice bread for each type of additive. Higher bioavailability of iron, copper, calcium, and magnesium was noted in rice bread, while the bioavailability of zinc was higher in buckwheat bread. CONCLUSION: The additives used increased the bioavailability of the analyzed minerals from the gluten-free breads. The use of various variants of flour (rice, buckwheat) influenced the bioavailability of iron, zinc, copper, calcium, and magnesium. The release of minerals from gluten-free bread depends on the element and added components (seeds or synthetic additives).


Assuntos
Pão , Glutens/química , Minerais/metabolismo , Compostos Orgânicos/química , Sementes/metabolismo , Disponibilidade Biológica , Ingestão de Energia
18.
Molecules ; 26(6)2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33804158

RESUMO

An artificial neural network model is proposed for the surface tension of liquid organic fatty acids covering a wide temperature range. A set of 2051 data collected for 98 acids (including carboxylic, aliphatic, and polyfunctional) was considered for the training, testing, and prediction of the resulting network model. Different architectures were explored, with the final choice giving the best results, in which the input layer has the reduced temperature (temperature divided by the critical point temperature), boiling temperature, and acentric factor as an independent variable, a 41-neuron hidden layer, and an output layer consisting of one neuron. The overall absolute percentage deviation is 1.33%, and the maximum percentage deviation is 14.53%. These results constitute a major improvement over the accuracy obtained using corresponding-states correlations from the literature.


Assuntos
Ácidos/química , Compostos Orgânicos/química , Redes Neurais de Computação , Tensão Superficial , Temperatura
19.
Int J Mol Sci ; 22(6)2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33799613

RESUMO

A novel framework for inverse quantitative structure-activity relationships (inverse QSAR) has recently been proposed and developed using both artificial neural networks and mixed integer linear programming. However, classes of chemical graphs treated by the framework are limited. In order to deal with an arbitrary graph in the framework, we introduce a new model, called a two-layered model, and develop a corresponding method. In this model, each chemical graph is regarded as two parts: the exterior and the interior. The exterior consists of maximal acyclic induced subgraphs with bounded height, the interior is the connected subgraph obtained by ignoring the exterior, and the feature vector consists of the frequency of adjacent atom pairs in the interior and the frequency of chemical acyclic graphs in the exterior. Our method is more flexible than the existing method in the sense that any type of graphs can be inferred. We compared the proposed method with an existing method using several data sets obtained from PubChem database. The new method could infer more general chemical graphs with up to 50 non-hydrogen atoms. The proposed inverse QSAR method can be applied to the inference of more general chemical graphs than before.


Assuntos
Algoritmos , Modelos Químicos , Compostos Orgânicos/química , Relação Quantitativa Estrutura-Atividade , Bases de Dados de Compostos Químicos , Modelos Moleculares , Estrutura Molecular
20.
J Vis Exp ; (168)2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33645576

RESUMO

Estimations of soil organic carbon are dependent on soil processing methods including removal of undecomposed plant material. Inadequate separation of roots and plant material from soil can result in highly variable carbon measurements. Methods to remove the plant material are often limited to the largest, most visible plant materials. In this manuscript we describe how electrostatic attraction can be used to remove plant material from a soil sample. An electrostatically charged surface passed close to dry soil naturally attracts both undecomposed and partially decomposed plant particles, along with a small quantity of mineral and aggregated soil. The soil sample is spread in a thin layer on a flat surface or a soil sieve. A plastic or glass Petri dish is electrostatically charged by rubbing with polystyrene foam or nylon or cotton cloth. The charged dish is passed repeatedly over the soil. The dish is then brushed clean and recharged. Re-spreading the soil and repeating the procedure eventually results in a diminishing yield of particulates. The process removes about 1 to 5% of the soil sample, and about 2 to 3 times that proportion in organic carbon. Like other particulate removal methods, the endpoint is arbitrary and not all free particulates are removed. The process takes approximately 5 min and does not require a chemical process as do density flotation methods. Electrostatic attraction consistently removes material with higher than average C concentration and C:N ratio, and much of the material can be visually identified as plant or faunal material under a microscope.


Assuntos
Compostos Orgânicos/química , Material Particulado/análise , Solo/química , Eletricidade Estática , Carbono/análise , Plantas/química , Plásticos/química
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