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1.
Int J Biol Macromol ; 269(Pt 2): 131906, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38679266

RESUMEN

The aim of this research was evaluation of the influence of distance between zwitterionic monomer ions on the performance of superabsorbents. For this purpose, two zwitterionic monomers 4-(3-aminopropyl) amino-4-oxo-2-butenoic acid (APOB) and 4-(6-aminohexyl) amino-4-oxo-2-butenoic acid (AHOB) were prepared and applied for synthesis of two new superabsorbents through graft copolymerization onto hydroxyethyl cellulose (HEC) in the presence of acrylic acid (AA). In synthesis of superabsorbents factors such as the highest water absorbency capacity, absorbency rate, gel strength, and environmental problems should be resolved or improved. The results demonstrated that the water absorbency capacity and rate parameters (τ) of HEC-g-p(AA-co-APOB) and HEC-g-p(AA-co-AHOB) in distilled water were 986.62, 664.38 g/g, and 98.04, 140.84 min, respectively. The biodegradability of HEC-g-p(AA-co-APOB) was approximately 4 times more than HEC-g-p(AA-co-AHOB). However, based on the rheological analyses (G'/G″) HEC-g-p(AA-co-AHOB) was stronger than the other. Additionally, studies of water retention on soil containing HEC-g-p(AA-co-AHOB) superabsorbent (soil with 0.25 wt% material) showed that the after 30 days has ≤5 % water while soil in the absence of superabsorbent after 10 days completely dried. Studies of the growth of plants in soil demonstrated in the presence of HEC-g-p(AA-co-AHOB) the average length of shoots was 36 cm while without superabsorbent were 25 cm.


Asunto(s)
Celulosa , Agua , Celulosa/química , Celulosa/análogos & derivados , Agua/química , Absorción Fisicoquímica , Acrilatos
2.
Int J Biol Macromol ; 268(Pt 1): 131845, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38677695

RESUMEN

Researchers have begun focusing on developing biodegradable materials, such as natural fiber/polymer composites (NFPC), since the growing of environmental concerns related to waste management. One crucial aspect that must be established in the development of these composites is their water-absorption behavior. This paper examines the water absorption (WA) behavior of NFPC, with a specific emphasis on natural fiber/polylactic acid (PLA) composites. It discusses processes and numerous aspects related to this behavior, based on recent published research. This review analyzes the influence of several factors, such as the loading of natural fiber, the combination of different natural fibers, the methods used in manufacturing, and the temperature of the water, on the WA behavior of natural fiber/PLA composites. It also explores how WA affects the properties of these composites. In addition, this review also presented techniques for improving the WA resistance of the composites. This review paper provides researchers with insights into the WA behavior of the composites, aiming to facilitate the development of a versatile and eco-friendly material that may effectively address waste disposal challenges.


Asunto(s)
Poliésteres , Agua , Poliésteres/química , Agua/química , Temperatura , Absorción Fisicoquímica
3.
Int J Biol Macromol ; 268(Pt 2): 131844, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38663708

RESUMEN

Starch is a key element in fried potato crisps, however, the effect of starch granule size on oil absorption of the product have yet to be fully investigated. The study explored the impact of starch granule size on both the dough characteristics and oil absorption in potato crisps. The dough composed of small-sized potato granules showed more compact and uniform network system. Additionally, X-ray Microscope analysis showed that potato crisps prepared with small-sized potato granules had limited matrix expansion and fewer pores, cracks, and voids. The small-sized potato and small-sized wheat starches granule addition crisps displayed a significantly greater average cell thickness (52.05 and 53.44 µm) than other samples, while exhibiting notably lower average porosity (61.37 % and 60.28 %) compared to other samples. Results revealed that potato crisps with medium and small potato granules had 12.91 % and 21.92 % lower oil content than those containing large potato starch. Potato crisps with B-type wheat starch showed 16.36 % less oil absorption than those with A-type wheat starch. Small-sized starches significantly influence the dough structure and contribute to the reduction of oil absorption in fried products. The generated insights may provide monitoring indexes for cultivating potato varieties with low oil absorption.


Asunto(s)
Solanum tuberosum , Almidón , Solanum tuberosum/química , Almidón/química , Tamaño de la Partícula , Culinaria , Porosidad , Harina/análisis , Absorción Fisicoquímica , Aceites de Plantas/química
4.
J Mol Biol ; 436(5): 168357, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-37944794

RESUMEN

Phytochromes constitute a family of photosensory proteins that are utilized by various organisms to regulate several physiological processes. Phytochromes bind a bilin pigment that switches its isomeric state upon absorption of red or far-red photons, resulting in protein conformational changes that are sensed by the organism. Previously, the ultrafast dynamics in bacterial phytochrome was resolved to atomic resolution by time-resolved serial femtosecond X-ray diffraction (TR-SFX), showing extensive changes in its molecular conformation at 1 picosecond delay time. However, the large excitation fluence of mJ/mm2 used in TR-SFX questions the validity of the observed dynamics. In this work, we present an excitation-dependent ultrafast transient absorption study to test the response of a related bacterial phytochrome to excitation fluence. We observe excitation power-dependent sub-picosecond dynamics, assigned to the population of high-lying excited state Sn through resonantly enhanced two-photon absorption, followed by rapid internal conversion to the low-lying S1 state. Inspection of the long-lived spectrum under high fluence shows that in addition to the primary intermediate Lumi-R, spectroscopic signatures of solvated electrons and ionized chromophore radicals are observed. Supported by numerical modelling, we propose that under excitation fluences of tens of µJ/mm2 and higher, bacterial phytochrome partly undergoes photoionization from the Sn state in competition with internal conversion to the S1 state in 300 fs. We suggest that the extensive structural changes of related, shorter bacterial phytochrome, lacking the PHY domain, resolved from TR-SFX may have been affected by the ionized species. We propose approaches to minimize the two-photon absorption process by tuning the excitation spectrum away from the S1 absorption or using phytochromes exhibiting minimized or shifted S1 absorption.


Asunto(s)
Proteínas Bacterianas , Fitocromo , Proteínas Bacterianas/química , Pigmentos Biliares/química , Isomerismo , Fitocromo/química , Análisis Espectral , Absorción Fisicoquímica , Conformación Proteica , Difracción de Rayos X
5.
Braz. dent. sci ; 27(2): 1-7, 2024. ilus, tab
Artículo en Inglés | LILACS, BBO | ID: biblio-1570673

RESUMEN

Objective: Mouthguards can reduce or even prevent orofacial injuries. These devices are responsible for absorbing part of the energy of an impact force, while the remaining part is dissipated. The present study aimed to evaluate how the plasticization temperature of the sports mouthguards' manufacturing process influences their mechanical properties and protective potential. Material and Methods: Specimens were made according to different plasticization temperatures (85°C, 103°C, 121°C and 128°C) and different dental brands of EVA sheets (Bio-art and FGM). Plasticization temperatures were measured using a culinary thermometer (Term; TP300). The mechanical properties evaluated were: energy absorption capacity, deformation, and modulus of elasticity. Compression testing was carried out in the Emic universal testing machine with a speed of 600 mm/min to simulate a punch. Results: EVA sheets submitted to the highest temperatures (121°C and 128°C) had their energy absorption capacity reduced. In addition, the samples that plasticized at the lowest temperature (85°C) showed higher absorption capacity, lower elastic modulus, and less variation in its dimensions. It proved to be the most effective in protection and with greater durability. Conclusion: The plasticization temperature proved to be an influential factor in the absorption capacity of mouthguards, so the increase in temperature led to a reduction in this property, especially when higher than 120°C. In addition, the plasticization temperature may vary depending on the sheet brand used. Finally, the kitchen thermometer used proved to be efficient and practical, thanks to its easy-to-read display and wide availability on the market. (AU)


Objetivo: Os protetores bucais são capazes de reduzir ou mesmo prevenir lesões orofaciais. Esses dispositivos são responsáveis por absorver parte da energia de uma força de impacto, enquanto a parte restante é dissipada. Este estudo teve como objetivo avaliar como a temperatura de plastificação de protetores bucais esportivos influencia em suas propriedades mecânicas e no seu potencial protetivo. Material e Métodos: Foram confeccionados modelos de trabalho segundo diferentes temperaturas de plastificação (85°C, 103°C, 121°C e 128°C) e distintas marcas odontológicas de placas de EVA (Bio-art e FGM). As temperaturas de plastificação foram medidas com termômetro culinário da marca Term/TP300. As propriedades mecânicas avaliadas foram capacidade de absorção de energia, deformação e módulo de elasticidade. O teste de compressão foi realizado na máquina de ensaios universal Emic com velocidade de 600 mm/min, a fim de simular um soco. Resultados: As placas de EVA submetidas às mais altas temperaturas (121°C e 128°C) tiveram sua capacidade de absorção de energia reduzida. Além disso, as amostras que plastificaram na temperatura mais baixa (85°C) apresentaram maior capacidade de absorção, menor módulo de elasticidade e menor variação em suas dimensões. Assim, mostraram-se a mais eficaz na proteção e com maior durabilidade. Conclusão: A temperatura de plastificação demonstrou ser um fator influente na capacidade de absorção dos protetores bucais, de modo que o aumento da temperatura levou a uma redução desta propriedade, principalmente quando superior a 120°C. Além disso, a temperatura de plastificação pode variar dependendo da marca comercial utilizada. Por fim, o termômetro culinário utilizado mostrou-se eficiente e prático, pela facilidade de leitura e por ser facilmente encontrado no mercado (AU)


Asunto(s)
Temperatura , Polietileno , Módulo de Elasticidad , Absorción Fisicoquímica , Protectores Bucales
6.
Braz. j. oral sci ; 22: e231377, Jan.-Dec. 2023. tab, ilus
Artículo en Inglés | LILACS, BBO | ID: biblio-1519248

RESUMEN

The aim of this study was to investigate the influence of the quantity and positioning of feldspathic ceramic specimens inside the furnace on their flexural strength and translucency. The tested hypotheses were that the arrangement of specimens in the furnance would not influence 1) the translucency or 2) the biaxial strength of the porcelain. Methods: Ninety porcelain specimens were made (1.2 mm thickness and 13.5 mm diameter) and assigned into two main groups (n=15): G1 group - 15 firing cycles containing only one specimen each, always at the center of the refractory; and G5 group - 15 firing cycles containing five specimen each, where one specimen was at the center of the refractory and four specimens positioned equidistantly on the periphery. The translucency test was performed using a spectrophotometer, followed by the flexural strength test, according to ISO 6872:2015. T-student test was performed for both the mechanical and optical obtained data. Results: The flexural strength of the porcelain was not affected by the positioning (center x periphery) of the specimens inside the furnace (p =0.08), but the translucency was affected (periphery > center; p =0.009). Regarding to the number of feldspathic ceramic specimens, the biaxial flexural strength was affected (p =0.025), as well as the translucency (p <0.05). Conclusion: A higher quantity of feldspathic ceramic specimens for each firing cycle decreased its biaxial flexural strength and translucency. Also, specimens positioned at the center of the refractory became less translucent than those positioned at the periphery.


Asunto(s)
Humanos , Termodinámica , Porcelana Dental/química , Absorción Fisicoquímica , Resistencia Flexional , Luz , Espectrofotometría , Temperatura , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Fractografía
7.
Nature ; 610(7930): 74-80, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36163287

RESUMEN

The adverse impact of particulate air pollution on human health1,2 has prompted the development of purification systems that filter particulates out of air3-5. To maintain performance, the filter units must inevitably be replaced at some point, which requires maintenance, involves costs and generates solid waste6,7. Here we show that an ion-doped conjugated polymer-coated matrix infiltrated with a selected functional liquid enables efficient, continuous and maintenance-free air purification. As the air to be purified moves through the system in the form of bubbles, the functional fluid provides interfaces for filtration and for removal of particulate matter and pollutant molecules from air. Theoretical modelling and experimental results demonstrate that the system exhibits high efficiency and robustness: its one-time air purification efficiency can reach 99.6%, and its dust-holding capacity can reach 950 g m-2. The system is durable and resistant to fouling and corrosion, and the liquid acting as filter can be reused and adjusted to also enable removal of bacteria or odours. We anticipate that our purification approach will be useful for the development of specialist air purifiers that might prove useful in a settings such as hospitals, factories and mines.


Asunto(s)
Absorción Fisicoquímica , Contaminantes Atmosféricos , Filtración , Material Particulado , Contaminantes Atmosféricos/química , Contaminantes Atmosféricos/aislamiento & purificación , Bacterias/aislamiento & purificación , Polvo/prevención & control , Filtración/instrumentación , Filtración/métodos , Humanos , Odorantes/prevención & control , Material Particulado/química , Material Particulado/aislamiento & purificación , Polímeros/química , Residuos Sólidos
8.
J Colloid Interface Sci ; 625: 596-605, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35764041

RESUMEN

In this study, biochar derived from municipal sludge (SBC) was modified by CoFe-Layered double hydroxides (CoFe-LDH), and used as adsorbent and oxidant for the removal of ciprofloxacin (CIP) for the first time. Under the optimal conditions, the CIP removal rate is increased by 24% compared with the single SBC, while the removal rates of total organic carbon and total nitrogen in the modified one are increased by 24% and 27%, respectively. Mechanism investigation suggested that the specific surface area and adsorption sites of modified biochar increased, and more CIP was adsorbed to the composite surface and then oxidized by more environmental persistent free radicals contained in the CoFe-LDH@SBC, when the adsorbed CIP molecules was oxidized and degraded, the adsorption sites can be freed and thus new CIP could be adsorbed to the CoFe-LDH@SBC. In addition, the plausible degradation pathways of CIP were proposed according to high-performance liquid chromatography-mass spectrometry and density functional theory calculation. It not only reveals that CoFe-LDH@SBC has the high ability of adsorption and oxidation for CIP removal but also sheds novel insight into the application of biochar.


Asunto(s)
Carbón Orgánico , Ciprofloxacina , Aguas del Alcantarillado , Contaminantes Químicos del Agua , Absorción Fisicoquímica , Adsorción , Carbón Orgánico/química , Ciprofloxacina/química , Hidróxidos , Aguas del Alcantarillado/química , Contaminantes Químicos del Agua/química
9.
Int J Biol Macromol ; 194: 632-643, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34822819

RESUMEN

Recently, the high-value utilization of food wastes has attracted great interest in sustainable development. Focusing on the major application of electrochemical energy storage (ECES), light-weight lignin-based carbon nanofibers (LCNFs) were controllably fabricated as supercapacitors from melon seed shells (MSS) and peanut shells (PS) through electrospinning and carbonizing processes. As a result, the optimal specific capacitance of 533.7 F/g in three-electrode system, energy density of 69.7 Wh/kg and power density of 780 W/Kg in two-electrode system were achieved. Surprisingly, the LCNFs also presented a satisfied electromagnetic absorption property: The minimum reflection loss (RL) value reached -37.2 dB at an absorbing frequency of 7.98 GHz with an effective frequency (RL < 10 dB) of 2.24 GHz (6.88 to 9.12 GHz) at a thickness of 3.0 mm. These features make the multifunctional LCNFs highly attractive for light-weight supercapacitor electrodes and electromagnetic wave absorbers applications.


Asunto(s)
Cucurbitaceae/metabolismo , Capacidad Eléctrica , Lignina/química , Nanofibras/química , Eliminación de Residuos/métodos , Absorción Fisicoquímica , Carbono/química , Semillas/química
10.
BMC Plant Biol ; 21(1): 599, 2021 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-34915868

RESUMEN

BACKGROUND: Soil salinization extensively hampers the growth, yield, and quality of crops worldwide. The most effective strategies to counter this problem are a) development of crop cultivars with high salt tolerance and b) the plantation of salt-tolerant crops. Glycyrrhiza inflata, a traditional Chinese medicinal and primitive plant with salt tolerance and economic value, is among the most promising crops for improving saline-alkali wasteland. However, the underlying molecular mechanisms for the adaptive response of G. inflata to salinity stress remain largely unknown. RESULT: G. inflata retained a high concentration of Na+ in roots and maintained the absorption of K+, Ca2+, and Mg2+ under 150 mM NaCl induced salt stress. Transcriptomic analysis of G. inflata roots at different time points of salt stress (0 min, 30 min, and 24 h) was performed, which resulted in 70.77 Gb of clean data. Compared with the control, we detected 2645 and 574 differentially expressed genes (DEGs) at 30 min and 24 h post-salt-stress induction, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that G. inflata response to salt stress post 30 min and 24 h was remarkably distinct. Genes that were differentially expressed at 30 min post-salt stress induction were enriched in signal transduction, secondary metabolite synthesis, and ion transport. However, genes that were differentially expressed at 24 h post-salt-stress induction were enriched in phenylpropane biosynthesis and metabolism, fatty acid metabolism, glycerol metabolism, hormone signal transduction, wax, cutin, and cork biosynthesis. Besides, a total of 334 transcription factors (TFs) were altered in response to 30 min and 24 h of salt stress. Most of these TFs belonged to the MYB, WRKY, AP2-EREBP, C2H2, bHLH, bZIP, and NAC families. CONCLUSION: For the first time, this study elucidated the salt tolerance in G. inflata at the molecular level, including the activation of signaling pathways and genes that regulate the absorption and distribution of ions and root growth in G. inflata under salt stress conditions. These findings enhanced our understanding of the G. inflata salt tolerance and provided a theoretical basis for cultivating salt-tolerant crop varieties.


Asunto(s)
Glycyrrhiza/crecimiento & desarrollo , Transporte Iónico , Raíces de Plantas/crecimiento & desarrollo , Estrés Salino , Absorción Fisicoquímica , Regulación de la Expresión Génica de las Plantas , Ontología de Genes , Glycyrrhiza/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento , Raíces de Plantas/metabolismo , RNA-Seq , Tolerancia a la Sal , Sodio/metabolismo , Transcriptoma
11.
Molecules ; 26(19)2021 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-34641557

RESUMEN

Using bamboo powder biochar as raw material, high-quality meso/microporous controlled hierarchical porous carbon was prepared-through the catalysis of Fe3+ ions loading, in addition to a chemical activation method-and then used to adsorb copper ions in an aqueous solution. The preparation process mainly included two steps: load-alkali leaching and chemical activation. The porosity characteristics (specific surface area and mesopore ratio) were controlled by changing the K2CO3 impregnation ratio, activation temperature, and Fe3+ ions loading during the activation process. Additionally, three FBPC samples with different pore structures and characteristics were studied for copper adsorption. The results indicate that the adsorption performance of the bamboo powder biochar FBPC material was greatly affected by the meso/micropore ratio. FBPC 2.5-900-2%, impregnated at a K2CO3: biochar ratio of 2.5 and a Fe3+: biochar mass ratio of 2%, and activated at 900 °C for 2 h in N2 atmosphere, has a very high specific surface area of 1996 m2 g-1 with a 58.1% mesoporous ratio. Moreover, it exhibits an excellent adsorption capacity of 256 mg g-1 and rapid adsorption kinetics for copper ions. The experimental results show that it is feasible to control the hierarchical pore structure of bamboo biochar-derived carbons as a high-performance adsorbent to remove copper ions from water.


Asunto(s)
Carbono/química , Cloruros/química , Cobre/química , Compuestos Férricos/química , Sasa/química , Absorción Fisicoquímica , Carbón Orgánico/química , Polvos/química , Espectrofotometría Atómica/instrumentación , Espectrofotometría Atómica/métodos , Purificación del Agua/métodos
12.
Life Sci ; 286: 120042, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34678262

RESUMEN

At present, little information on the biopharmaceutical behaviour of proton pump inhibitors (PPIs) describing their absorption and biodistribution in vivo has been reported because the extreme instability of PPIs in the gastrointestinal environment makes it difficult to analyze such behaviour. In this work, a modified rat in situ intestinal perfusion model was employed to investigate absorption in the gastrointestinal tract and subsequent biodistribution of several PPIs (ilaprazole, esomeprazole and rabeprazole), which have different physicochemical properties. Our data indicated that PPIs exhibited significantly enhanced absorption rates in the whole intestine, including the duodenum, jejunum, ileum and colon, corresponding to the increase in the oil-water partition coefficient (LogP). PPIs and corresponding salt types showed no obvious differences in absorption, implying that solubility changes in the PPI have little effect on its absorption in the gastrointestinal tract. Among these PPIs, ilaprazole presented a more stable intestinal absorption behaviour, as well as more distribution and longer residence time in the stomach by HPLC-MS/MS analysis and radioactivity counts after 14C radiolabelling. These results may be useful information for PPI optimization and oral formulation design.


Asunto(s)
Absorción Fisicoquímica/efectos de los fármacos , Absorción Intestinal/efectos de los fármacos , Inhibidores de la Bomba de Protones/farmacología , 2-Piridinilmetilsulfinilbencimidazoles/farmacología , Absorción Fisicoquímica/fisiología , Adsorción , Animales , Productos Biológicos/farmacocinética , Productos Biológicos/farmacología , Fenómenos Químicos/efectos de los fármacos , China , Esomeprazol/farmacología , Femenino , Íleon/metabolismo , Absorción Intestinal/fisiología , Yeyuno/metabolismo , Masculino , Inhibidores de la Bomba de Protones/metabolismo , Inhibidores de la Bomba de Protones/farmacocinética , Rabeprazol/farmacología , Ratas , Ratas Sprague-Dawley , Espectrometría de Masas en Tándem/métodos , Distribución Tisular/efectos de los fármacos
13.
Int J Biol Macromol ; 190: 224-232, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34481857

RESUMEN

Cassava starch has acquired many attentions owing to its ability to be developed as thermoplastic cassava starch (TPCS) where it can be obtained in low cost, making it to be one of alternatives to substitute petroleum-based plastic. An attempt was made to investigate the thermal, mechanical and moisture absorption properties of thermoplastic cassava starch blending with beeswax (TPCS-BW) fabricated using hot moulding compression method in the range of beeswax loading from 0, 2.5, 5 to 10 wt%. Addition of beeswax has significantly reduced tensile strength, elongation and flexural strength while improving tensile modulus and flexural modulus until 5 wt% beeswax. Incorporation of 10 wt% beeswax has successfully produced the lowest value of moisture absorption and water solubility among the bio-composite which might be attributed to the beeswax's hydrophobic properties in improving water barrier of the TPCS-BW bio-composite. Furthermore, the addition of beeswax resulted in the appearance of irregular and rough fractured surface. Meanwhile, fourier transform infrared (FT-IR) spectroscopy presented that incorporation of beeswax in the mixture has considerably improve hydrogen bonding of blends indicating good interaction between starch and beeswax. Hence, beeswax with an appropriate loading value able to improve the functional properties of TPCS-BW bio-composite.


Asunto(s)
Absorción Fisicoquímica , Humedad , Plásticos/química , Almidón/química , Temperatura , Ceras/química , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Resistencia a la Tracción , Termogravimetría , Agua/química
14.
Biomolecules ; 11(9)2021 09 11.
Artículo en Inglés | MEDLINE | ID: mdl-34572560

RESUMEN

In this study, cellulose nanofibrils (CNFs) were modified by catalyzed lactic acid esterification in an aqueous medium with SnCl2 as a catalyst. Films were made from unmodified and lactic acid-modified CNF without a polymer matrix to evaluate the effectiveness of the modification. Ungrafted and lactic acid-grafted CNF was also compounded with poly(lactic acid) (PLA) to produce composites. Mechanical, water absorption, and barrier properties were evaluated for ungrafted CNF, lactic acid-grafted CNF films, and PLA/CNF composites to ascertain the effect of lactic acid modification on the properties of the films and nanocomposites. FTIR spectra of the modified CNF revealed the presence of carbonyl peaks at 1720 cm-1, suggesting that the esterification reaction was successful. Modification of CNF with LA improved the tensile modulus of the produced films but the tensile strength and elongation decreased. Additionally, films made from modified CNF had lower water absorption, as well as water vapor and oxygen permeability, relative to their counterparts with unmodified CNFs. The mechanical properties of PLA/CNF composites made from lactic acid-grafted CNFs did not significantly change with respect to the ungrafted CNF. However, the addition of lactic acid-grafted CNF to PLA improved the water vapor permeability relative to composites containing ungrafted CNF. Therefore, the esterification of CNFs in an aqueous medium may provide an environmentally benign way of modifying the surface chemistry of CNFs to improve the barrier properties of CNF films and PLA/CNF composites.


Asunto(s)
Celulosa/química , Ácido Láctico/química , Nanofibras/química , Poliésteres/química , Absorción Fisicoquímica , Esterificación , Nanofibras/ultraestructura , Oxígeno/análisis , Permeabilidad , Espectroscopía Infrarroja por Transformada de Fourier , Vapor , Propiedades de Superficie , Resistencia a la Tracción , Agua/química
15.
Int J Mol Sci ; 22(17)2021 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-34502455

RESUMEN

During biogas combustion, siloxanes form deposits of SiO2 on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the 1H NMR, 13C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.


Asunto(s)
Biocombustibles , Monoterpenos Ciclohexánicos/química , Siloxanos/aislamiento & purificación , Solventes/química , Absorción Fisicoquímica
16.
PLoS One ; 16(8): e0255694, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34343208

RESUMEN

Thai indigenous brown rice flours from Nakhon Si Thammarat, Thailand, namely Khai Mod Rin (KMRF) and Noui Khuea (NKRF), were assessed for quality aspects in comparison with brown Jasmine rice flour (JMRF) and commercial rice flour (CMRF) from Chai Nat 1 variety. All the rice flours had different chemical composition, physical characteristic, and techno-functionality. The KMRF, NKRF, and JMRF were classified as a low amylose type (19.56-21.25% dw). All rice flours had low total extractable phenolic content (0.1-0.3 mg GAE/g dw) with some DPPH● scavenging activity (38.87-46.77%). The variations in the bulk density (1.36-1.83 g/cm3), water absorption capacity (0.71-1.17 g/g), solubility (6.93-13.67%), oil absorption capacity (1.39-2.49 g/g), and swelling power (5.71-6.84 g/g) were noticeable. The least gelation concentration ranged from 4.0 to 8.0% where KMRF was easier to form gel than JMRF, and NKRF/CMRF. The foam capacity of the flours was relatively low (1.30-2.60%). The pasting properties differed among rice flours and the lowest pasting temperature was observed in CMRF. Overall, the chemical, physical, functional, and pasting qualities of flours were substantially influenced by rice variety. The findings offered fundamental information on Thai indigenous rice flour that can be used in food preparations for specific uses.


Asunto(s)
Oryza/química , Semillas/química , Almidón/química , Absorción Fisicoquímica , Amilosa/análisis , Compuestos de Bifenilo/análisis , Geles , Fenoles/análisis , Picratos/análisis , Solubilidad , Temperatura , Tailandia , Viscosidad
17.
J Phys Chem Lett ; 12(34): 8384-8396, 2021 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-34435784

RESUMEN

This study utilizes the FMN-dependent NADH:quinone oxidoreductase from Pseudomonas aeruginosa PAO1 to investigate the effect of introducing an active site negative charge on the flavin absorption spectrum both in the absence and presence of a long-range electrostatic potential coming from solution ions. There were no observed changes in the flavin UV-visible spectrum when an active site tyrosine (Y277) becomes deprotonated in vitro. These results could only be reproduced computationally using average solvent electrostatic configuration (ASEC) QM/MM simulations that include both positive and negative solution ions. The same calculations performed with minimal ions to neutralize the total protein charge predicted that deprotonating Y277 would significantly alter the flavin absorption spectrum. Analyzing the distribution of solution ions indicated that the ions reorganize around the protein surface upon Y277 deprotonation to cancel the effect of the tyrosinate on the flavin absorption spectrum. Additional biochemical experiments were performed to test this hypothesis.


Asunto(s)
Absorción Fisicoquímica , Flavoproteínas/química , Dominio Catalítico , Modelos Moleculares , Soluciones
18.
Nature ; 595(7865): 58-65, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-34194019

RESUMEN

The natural world provides many examples of multiphase transport and reaction processes that have been optimized by evolution. These phenomena take place at multiple length and time scales and typically include gas-liquid-solid interfaces and capillary phenomena in porous media1,2. Many biological and living systems have evolved to optimize fluidic transport. However, living things are exceptionally complex and very difficult to replicate3-5, and human-made microfluidic devices (which are typically planar and enclosed) are highly limited for multiphase process engineering6-8. Here we introduce the concept of cellular fluidics: a platform of unit-cell-based, three-dimensional structures-enabled by emerging 3D printing methods9,10-for the deterministic control of multiphase flow, transport and reaction processes. We show that flow in these structures can be 'programmed' through architected design of cell type, size and relative density. We demonstrate gas-liquid transport processes such as transpiration and absorption, using evaporative cooling and CO2 capture as examples. We design and demonstrate preferential liquid and gas transport pathways in three-dimensional cellular fluidic devices with capillary-driven and actively pumped liquid flow, and present examples of selective metallization of pre-programmed patterns. Our results show that the design and fabrication of architected cellular materials, coupled with analytical and numerical predictions of steady-state and dynamic behaviour of multiphase interfaces, provide deterministic control of fluidic transport in three dimensions. Cellular fluidics may transform the design space for spatial and temporal control of multiphase transport and reaction processes.


Asunto(s)
Células/metabolismo , Microfluídica/instrumentación , Microfluídica/métodos , Absorción Fisicoquímica , Dióxido de Carbono/metabolismo , Gases/metabolismo , Nutrientes/metabolismo , Oxígeno/metabolismo , Transpiración de Plantas , Grabación de Videodisco , Agua/metabolismo
19.
J Phys Chem Lett ; 12(27): 6284-6291, 2021 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-34213348

RESUMEN

We report a transient signature in the near-UV absorption of Krokinobacter eikastus rhodopsin 2 (KR2), which spans from the femtosecond up to the millisecond time scale. The signature rises with the all-trans to 13-cis isomerization of retinal and decays with the reisomerization to all-trans in the late photocycle, making it a promising marker band for retinal configuration. Hybrid quantum mechanics/molecular mechanics simulations show that the near-UV absorption signal corresponds to an S0 → S3 and/or an S0 → S5 transition, which is present in all photointermediates. These transitions exhibit a negligible spectral shift by the altering protein environment, in contrast to the main absorption band. This is rationalized by the extension of the transition densities that omits the Schiff base nitrogen. Further characterization and first steps into possible optogenetic applications were performed with near-UV quenching experiments of an induced photostationary state, yielding an ultrafast regeneration of the parent state of KR2.


Asunto(s)
Absorción Fisicoquímica , Flavobacteriaceae/metabolismo , Rodopsina/química , Rodopsina/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Rayos Ultravioleta , Membrana Celular/metabolismo , Flavobacteriaceae/citología , Simulación de Dinámica Molecular , Conformación Proteica , Análisis Espectral
20.
Ultrason Sonochem ; 76: 105655, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34225214

RESUMEN

Resistant starch type 2 (RS) was isolated from lotus stem using enzymatic digestion method. The isolated RS was subjected to ultrasonication (US) at different sonication power (100-400 W). The US treated and untreated RS samples were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), light microscopy and Fourier transform infrared spectroscopy (FT-IR). DLS revealed that particle size of RS decreased from 12.80 µm to 413.19 nm and zeta potential increased from -12.34 mV to -26.09 mV with the increase in sonication power. SEM revealed smaller, disintegrated and irregular shaped RS particles after ultrasonication. FT-IR showed the decreased the band intensity at 995 cm-1 and 1047 cm-1 signifying that US treatment decreased the crystallinity of RS and increased its amorphous character. The bile acid binding, anti-oxidant and pancreatic lipase inhibition activity of samples also increased significantly (p < 0.05) with the increase in sonication power. Increase in US power however increased the values of hydrolysis from 23.11 ± 1.09 to 36.06 ± 0.13% and gylcemic index from 52.39 ± 0.38 to 59.50 ± 0.11. Overall, the non-thermal process of ultrasonic treatment can be used to change the structural, morphological and nutraceutical profile of lotus stem resistant starch which can have great food and pharamaceutical applications.


Asunto(s)
Lotus/química , Tallos de la Planta/química , Almidón Resistente/análisis , Ondas Ultrasónicas , Absorción Fisicoquímica , Valor Nutritivo
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