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1.
Int J Biometeorol ; 68(11): 2413-2429, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39158720

RESUMO

Rice is one of the major food crops, and the study of suitable planting areas for rice plays an important role in improving rice yield and optimizing the production layout. This study used Maximum Entropy (MaxEnt) model to simulate and predict the distribution of suitable rice planting areas in China from 1981 to 2020 by combining the climate, soil, and human activities, analyzed the spatial and temporal changes of suitable rice planting areas in China, and determined the main factors affecting rice planting suitability. The results indicated that the main factors influencing the distribution of suitable planting areas for rice in China were gross domestic product (GDP), population density (Pop), and annual sunshine duration (Sun), with human activities playing a dominant role. The high suitable planting areas of rice were mainly distributed in Hubei, Hunan, Jiangxi, Anhui, Guangdong, southeastern Sichuan and western Guizhou. The total suitable planting areas for rice were 346.00 × 104 km2, 345.66 × 104 km2, 347.01 × 104 km2, and 355.57 × 104 km2 from 1981 to 1990, 1991 to 2000, 2001 to 2010 and 2011 to 2020, respectively. With the passage of time, the area of unsuitable areas for rice gradually decreased, and the area of medium suitable areas increased, with large changes in the area of high- and low-suitable areas. Moreover, due to the transfer of a large number of rural laborers to the cities in recent years, the tension between people and land caused by the population explosion has led to the increasing impact of Pop on rice suitable areas and the relatively weakening of the impact of GDP on rice production interventions. The results can be used to provide scientific evidence for the management of rice cultivation and food production safety, with a view to reducing the impacts of climate change on agricultural production in the context of global climate change.


Assuntos
Agricultura , Modelos Teóricos , Oryza , Oryza/crescimento & desenvolvimento , China , Humanos , Agricultura/métodos , Atividades Humanas , Solo/química , Entropia , Densidade Demográfica , Meio Ambiente , Luz Solar
2.
Sensors (Basel) ; 23(18)2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37765795

RESUMO

The acoustic diffusion equation model has been widely applied in various scenarios, but a larger prediction error exists when applied to underground spaces, showing a significantly lower characteristic of the sound pressure level in the later stage compared to field tests since underground spaces have a more closed acoustic environment. Therefore, we analyze the characteristics of underground spaces differentiating from aboveground spaces when applying the model and propose an improved model from the perspective of energy balance. The energy neglected in the calculation of the acoustic diffusion equation model is compensated in long channel underground spaces named "acoustic escape compensation". A simulation and two field experiments are conducted to verify the effectiveness of the proposed compensation strategy in long-channel underground spaces. The mean square error is used to evaluate the differences between the classical model and the improved model, which shows a numerical improvement of 1.3 in the underground field test. The results show that the improved model is more suitable for describing underground spaces. The proposed strategy provides an effective extension of the acoustic diffusion equation model to solve the problem of sound field prediction and management in underground spaces.

3.
J Org Chem ; 87(9): 6161-6178, 2022 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-35438486

RESUMO

An electrochemical approach to promote the ortho-C-H alkylation of (hetero)arenes via rhodium catalysis under mild conditions is described. This approach features mild conditions with high levels of regio- and monoselectivity that tolerate a variety of aromatic and heteroaromatic groups and offers a widely applicable method for late-stage diversification of complex molecular architectures including tryptophan, estrone, diazepam, nucleosides, and nucleotides. Alkyl boronic acids and esters and alkyl trifluoroborates are demonstrated as suitable coupling partners. The isolation of key rhodium intermediates and mechanistic studies provided strong support for a rhodium(III/IV or V) regime.


Assuntos
Ródio , Alquilação , Catálise , Eletroquímica , Nucleosídeos , Nucleotídeos , Ródio/química
4.
Environ Sci Technol ; 56(15): 10638-10645, 2022 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-35839311

RESUMO

Persistent free radicals (PFRs) in biochar can influence biochar reactivity, promoting organic contaminant degradation or even causing certain toxic impacts. However, the PFR generation mechanism is not still well understood. An investigation of the relationship between PFR formation and the chemical structure of biochar is essential for understanding the PFR formation mechanism. Our in situ measurement results showed that PFR intensities increased from 0-509.5 to 146-5678 a.u. after being pyrolyzed at 300 °C for 60 min. The significant positive correlation between PFR intensities and the peak areas of C═O and aromatic C═C groups indicated that the generation of PFRs was highly dependent on the C═O and aromatic C═C structures. The reduction of biochars by KBH4 resulted in a 32.2 ± 2.49% decrease in the C═O content and a relative increase in the C-O content, while other physicochemical properties did not change. Thus, the observed 49.3% decrease in PFR signals after this reduction suggested that the reducible C═O groups, possibly in aldehydes, aromatic ketones, and quinones, were closely associated with PFRs in biochars. This study provides an in situ insight into the PFR generation mechanism and guides the corresponding biochar design and property manipulation.


Assuntos
Carvão Vegetal , Lignina , Carvão Vegetal/química , Radicais Livres/química
5.
Acc Chem Res ; 53(2): 300-310, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-31939278

RESUMO

Electrochemical synthesis of organic compounds has emerged as an attractive and environmentally benign alternative to conventional approaches for oxidation and reduction of organic compounds that utilizes electric current instead of chemical oxidants and reductants. As such, many useful transformations have been developed, including the Kolbe reaction, the Simons fluorination process, the Monsanto adiponitrile process, and the Shono oxidation, to name a few. Electrochemical C-H functionalization represents one of the most promising reaction types among many electrochemical transformations, since this process avoids prefunctionalization of substrates and provides novel retrosynthetic disconnections. However, site-selective anodic oxidation of C-H bonds is still a fundamental challenge due to the high oxidation potentials of C-H bonds compared to organic solvents and common functional groups. To overcome this issue, indirect electrolysis via the action of a mediator (a redox catalyst) is regularly employed, by which the selectivity can be controlled following reaction of said mediator with the substrate. Since the redox potentials of transition metal complexes can be easily tuned by modification of the ligand, the synergistic use of electrochemistry and transition metal catalysis to achieve site-selective C-H functionalization is an attractive strategy. In this Account, we summarize and contextualize our recent efforts toward transition metal-catalyzed electrochemical C-H functionalization proximal to a suitable directing group. We have developed C-H oxygenation, acylation, alkylation, and halogenation reactions in which a Pd(II) species is oxidized to a Pd(III) or Pd(IV) intermediate by anodic oxidation, followed by reductive elimination to form the corresponding C-O, C-C, and C-X bonds. Importantly, improved monofunctionalization selectivity is achieved in the Pd-catalyzed C(sp3)-H oxygenation compared to conventional approaches using PhI(OAc)2 as the chemical oxidant. Physical separators are sometimes used to prevent the electrochemical deposition of Pd black on the cathode resulting from reduction of high valent Pd species. We skirted this issue through the development a Cu-catalyzed electrochemical C(sp2)-H amination using n-Bu4NI as a redox cocatalyst in an undivided cell. In addition, we developed Ir-catalyzed electrochemical vinylic C-H functionalization of acrylic acids with alkynes in an undivided cell, affording various substituted α-pyrones in good to excellent yield. More importantly, chemical oxidants, including Ag2CO3, Cu(OAc)2, and PhI(OAc)2, resulted in much lower yields in the absence of electrical current under otherwise identical conditions. As elaborated below, progress in the area of electrochemical transition metal-catalyzed synthesis provides an effective platform for environmentally friendly and sustainable selective chemical transformations.

6.
J Org Chem ; 85(5): 3497-3507, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-31889446

RESUMO

A simple and mild protocol for copper-catalyzed bromination of quinoline at the C5 site of quinoline by anodic oxidation was developed, affording the desired remote C-H activation products with isolated yields of up to about 90%. The reaction proceeds with low-cost NH4Br and shows mild and green conditions (electricity as a green oxidant; NH3 and H2 as byproducts). At the same time, a gram-scale bromination reaction was also successfully fulfilled, showing its potential applicable value in organic synthesis. Moreover, the CV chart further demonstrated the proposed catalytic cycle.

7.
Environ Res ; 181: 108899, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31740041

RESUMO

In this work, corn straw (CS) based porous carbon was prepared by one-step phosphoric acid (H3PO4) low temperature activation. The impregnation ratios (H3PO4/CS, g/g) played an important role in the pore development. ACS300-1 engineered at 300 °C and the impregnation ratio of 1.0 showed the maximal specific surface area of 463.89 m2/g with total pore volume of 0.387 cm3/g, attaining a high tetracycline (TC) uptake of 227.3 mg/g. The adsorption of TC onto ACS300-1 was found tolerant with wide pH (2.0-10.0) and high ionic strength (0 - 0.5 M). The adsorption data can be fitted well by the pseudo-second order kinetic model and Langmuir isotherm model. The endothermic and spontaneous properties of the adsorption system was implied by Thermodynamic study. The findings of the current work conclude that one-step H3PO4 activation is a green and promising method for corn straw based porous carbon that may be found with great potentials in antibiotic containing wastewater treatment.


Assuntos
Antibacterianos , Carbono , Tetraciclina , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Ácidos Fosfóricos , Porosidade , Temperatura , Zea mays
8.
J Am Chem Soc ; 141(8): 3395-3399, 2019 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-30741543

RESUMO

We have developed a Ni-catalyzed enantioselective hydroarylation of styrenes with arylboronic acids using MeOH as the hydrogen source, providing an efficient method to access 1,1-diarylalkanes, which are essential structural units in many biologically active compounds. In addition, Ni-catalyzed enantioselective hydrovinylation of styrenes with vinylboronic acids is also realized with good yields and enantioselectivities. The synthetic utility was demonstrated by the efficient synthesis of ( R)-(-)-ibuprofen.

9.
J Am Chem Soc ; 141(48): 18970-18976, 2019 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-31714747

RESUMO

Synergistic use of electrochemistry and organometallic catalysis has emerged as a powerful tool for site-selective C-H functionalization, yet this type of transformation has thus far mainly been limited to arene C-H functionalization. Herein, we report the development of electrochemical vinylic C-H functionalization of acrylic acids with alkynes. In this reaction an iridium catalyst enables C-H/O-H functionalization for alkyne annulation, affording α-pyrones with good to excellent yields in an undivided cell. Preliminary mechanistic studies show that anodic oxidation is crucial for releasing the product and regeneration of an Ir(III) intermediate from a diene-Ir(I) complex, which is a coordinatively saturated, 18-electron complex. Importantly, common chemical oxidants such as Ag(I) or Cu(II) did not give significant amounts of the desired product in the absence of electrical current under otherwise identical conditions.

10.
J Am Chem Soc ; 140(36): 11487-11494, 2018 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-30165030

RESUMO

Electrochemical oxidation represents an environmentally friendly solution to conventional methods that require caustic stoichiometric chemical oxidants. However, C-H functionalizations merging transition-metal catalysis and electrochemical techniques are, to date, largely confined to the use of precious metals and divided cells. Herein, we report the first examples of copper-catalyzed electrochemical C-H aminations of arenes at room temperature using undivided electrochemical cells, thereby providing a practical solution for the construction of arylamines. The use of n-Bu4NI as a redox mediator is crucial for this transformation. On the basis of mechanistic studies including kinetic profiles, isotope effects, cyclic voltammetric analyses, and radical inhibition experiments, the reaction appears to proceed via a single-electron-transfer (SET) process, and a high valent Cu(III) species is likely involved. These findings provide a new avenue for transition-metal-catalyzed electrochemical C-H functionalization reactions using redox mediators.

11.
Sensors (Basel) ; 18(9)2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-30231472

RESUMO

Gesture recognition acts as a key enabler for user-friendly human-computer interfaces (HCI). To bridge the human-computer barrier, numerous efforts have been devoted to designing accurate fine-grained gesture recognition systems. Recent advances in wireless sensing hold promise for a ubiquitous, non-invasive and low-cost system with existing Wi-Fi infrastructures. In this paper, we propose DeepNum, which enables fine-grained finger gesture recognition with only a pair of commercial Wi-Fi devices. The key insight of DeepNum is to incorporate the quintessence of deep learning-based image processing so as to better depict the influence induced by subtle finger movements. In particular, we make multiple efforts to transfer sensitive Channel State Information (CSI) into depth radio images, including antenna selection, gesture segmentation and image construction, followed by noisy image purification using high-dimensional relations. To fulfill the restrictive size requirements of deep learning model, we propose a novel region-selection method to constrain the image size and select qualified regions with dominant color and texture features. Finally, a 7-layer Convolutional Neural Network (CNN) and SoftMax function are adopted to achieve automatic feature extraction and accurate gesture classification. Experimental results demonstrate the excellent performance of DeepNum, which recognizes 10 finger gestures with overall accuracy of 98% in three typical indoor scenarios.


Assuntos
Dedos , Gestos , Processamento de Imagem Assistida por Computador/métodos , Reconhecimento Automatizado de Padrão/métodos , Interface Usuário-Computador , Humanos , Redes Neurais de Computação
12.
J Am Chem Soc ; 139(8): 3293-3298, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28177235

RESUMO

Palladium-catalyzed C-H activation/C-O bond-forming reactions have emerged as attractive tools for organic synthesis. Typically, these reactions require strong chemical oxidants, which convert organopalladium(II) intermediates into the PdIII or PdIV oxidation state to promote otherwise challenging C-O reductive elimination. However, previously reported oxidants possess significant disadvantages, including poor atom economy, high cost, and the formation of undesired byproducts. To overcome these issues, we report an electrochemical strategy that takes advantage of anodic oxidation of PdII to induce selective C-O reductive elimination with a variety of oxyanion coupling partners.

13.
J Environ Biol ; 37(4): 485-91, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27498491

RESUMO

To obtain optimal irrigation management for young coffee tree, the effects of alternate drip irrigation (ADI) and superabsorbent polymers on physiology, growth, dry mass accumulation and water use on one-year old Coffea arabica L. tree were investigated. This experiment had three drip irrigation methods, i.e., conventional drip irrigation (CDI), alternate drip irrigation (ADI) and fixed drip irrigation (FDI), and two levels of superabsorbent polymers, i.e., no superabsorbent polymers (NSAP) and added superabsorbent polymers (SAP). Compared to CDI, ADI saved irrigation water by 32.1% and increased water use efficiency (WUE) by 29.9%. SAP increased root-shoot ratio, total dry mass and WUE by 20.3, 24.9 and 33.0%, respectively, when compared to NSAP. Compared to CDI with NSAP treatment, ADI with SAP treatment increased total dry mass by 13.8% and saved irrigation water by 34.4%, thus increased WUE by 73.4%, and it increased root activity, the contents of chlorophyll and soluble sugar in leaves by 162.4, 38.0 and 8.5%, but reduced the contents of proline and malondialdehyde in leaves by 7.2 and 9.7%, respectively. Thus, alternate drip irrigation with superabsorbent polymers increased the growth and WUE of young Coffea arabica L. tree and was optimal irrigation management for young coffee tree.


Assuntos
Irrigação Agrícola/métodos , Coffea/fisiologia , Polímeros/metabolismo , Água/metabolismo , Absorção Fisiológica , Coffea/crescimento & desenvolvimento , Transpiração Vegetal , Polímeros/administração & dosagem , Árvores
14.
Microorganisms ; 12(4)2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38674727

RESUMO

In the continuous cropping of Panax notoginseng, the pathogenic fungi in the rhizosphere soil increased and infected the roots of Panax notoginseng, resulting in a decrease in yield. This is an urgent problem that needs to be solved in order to effectively overcome the obstacles associated with the continuous cropping of Panax notoginseng. Previous studies have shown that Bacillus subtilis inhibits pathogenic fungi in the rhizosphere of Panax notoginseng, but the inhibitory effect was not stable. Therefore, we hope to introduce biochar to help Bacillus subtilis colonize in soil. In the experiment, fields planted with Panax notoginseng for 5 years were renovated, and biochar was mixed in at the same time. The applied amount of biochar was set to four levels (B0, 10 kg·hm-2; B1, 80 kg·hm-2; B2, 110 kg·hm-2; B3, 140 kg·hm-2), and Bacillus subtilis biological agent was set to three levels (C1, 10 kg·hm-2; C2, 15 kg·hm-2; C3, 25 kg·hm-2). The full combination experiment and a blank control group (CK) were used. The experimental results show that the overall Ascomycota decreased by 0.86%~65.68% at the phylum level. Basidiomycota increased by -73.81%~138.47%, and Mortierellomycota increased by -51.27%~403.20%. At the genus level, Mortierella increased by -10.29%~855.44%, Fusarium decreased by 35.02%~86.79%, and Ilyonectria increased by -93.60%~680.62%. Fusarium mainly causes acute bacterial wilt root rot, while Ilyonectria mainly causes yellow rot. Under different treatments, the Shannon index increased by -6.77%~62.18%, the Chao1 index increased by -12.07%~95.77%, the Simpson index increased by -7.31%~14.98%, and the ACE index increased by -11.75%~96.12%. The good_coverage indices were all above 0.99. The results of a random forest analysis indicated that Ilyonectria, Pyrenochaeta, and Xenopolyscytalum were the top three most important species in the soil, with MeanDecreaseGini values of 2.70, 2.50, and 2.45, respectively. Fusarium, the primary pathogen of Panax notoginseng, ranked fifth, and its MeanDecreaseGini value was 2.28. The experimental results showed that the B2C2 treatment had the best inhibitory effect on Fusarium, and the relative abundance of Fusarium in Panax notoginseng rhizosphere soil decreased by 86.79% under B2C2 treatment; the B1C2 treatment had the best inhibitory effect on Ilyonectria, and the relative abundance of Ilyonectria in the Panax notoginseng rhizosphere soil decreased by 93.60% under B1C2 treatment. Therefore, if we want to improve the soil with acute Ralstonia solanacearum root rot, we should use the B2C2 treatment to improve the soil environment; if we want to improve the soil with yellow rot disease, we should use the B1C2 treatment to improve the soil environment.

15.
J Hazard Mater ; 472: 134608, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38754229

RESUMO

Amphiphilic aromatic poly (amino acids) polymers were designed as biodegradability demulsifiers with higher aromaticity, stronger polarity, and side chain-like combs. The effects of demulsifier dosage, structural characteristics and emulsion properties such as pH, salinity, and oil content on the demulsification efficiency were investigated. The results show that the poly (L-glutamic-benzyl ester)-block-poly (L-phenylalanine) (PBLG15-b-PPA15) as the demulsifier can remove more than 99.97% of the oil in a 5.0 wt% oil-in-water (O/W) emulsion at room temperature within 2 min. The poly (L-tyrosine)-block-poly (L-phenylalanine) (PTyr15-b-PPA15) with environmental durability demonstrates high effectiveness, universality, and demulsification speed. It achieves a remarkable demulsification efficiency of up to 99.99% for a 20.0 wt% O/W emulsion at room temperature. The demulsification mechanism indicates that demulsifiers have sufficient interfacial activity can quickly migrate to the oil-water interface after being added to the emulsions. Additionally, when demulsifiers are present in a continuous phase in the molecular form, their "teeth" side chains are beneficial for increasing coalescence and flocculation capacities. Furthermore, according to the Density Functional Theory (DFT) calculations, enhancing the intermolecular interactions between demulsifiers and the primary native surfactants that form an oil-water interfacial film is a more efficient approach to reducing demulsification temperature and improving demulsification efficiency and rate.

16.
Materials (Basel) ; 17(4)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38399130

RESUMO

Plant-derived selenium is an important source of selenium (Se) for humans, which, however, has been restricted by a low content of Se in soil. Traditional Se fertilizers have tended to result in low selenium utilization. Thus, it was necessary to develop a new slow-release material to control Se fertilizer release. In this study, biochar pyrolyzed at 300 °C and 800 °C was cross-linked with polyethyleneimine (PEI) after being treated with HNO3 or NaOH (which were labeled Acid-W300, Acid-W800, Alkali-W300, and Alkali-W800). The results showed that the maximum adsorption capacities of Acid-W300, Alkali-W300, Acid-W800, and Alkali-W800 were 329.16 mg/g, 321.93 mg/g, 315.04 mg/g, and 344.33 mg/g, respectively. Among them, Acid-W800 and Alkali-W800 were mainly imine- and amide-bonded with SO32-, while Acid-W300 and Alkali-W300 were loaded with SO32- by forming the C-Se bonding as well as through imine- and amide-bonding. The release of four biochar-based selenium fertilizers in the red soil and brown soil extracts conformed to the pseudo-second-order kinetic model. The release rate and release amount of four biochar-based selenium fertilizers in the red soil extract were higher than those in the brown soil extract. Alkali-W800-Se had a higher proportion of Se-exchangeable release, accounting for 87.5% of the total loaded selenium, while Acid-W300-Se had the lowest proportion at 62.2%. However, the Se releases of Alkali-W800-Se were more than 42.49% and 37.67% of the total Se-loading capacity during 5 days of continuous red soil extraction and brown soil extraction, respectively. Acid-W300-Se released less than 20% of the total Se-loading capacity. Thus, Acid-W300-Se was the recommended slow-release Se fertilizer in red soil and brown soil.

17.
Sci Total Environ ; 949: 175038, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39059663

RESUMO

Rice is one of the world's major food crops. Changes in major climatic factors such as temperature, rainfall, solar radiation and carbon dioxide (CO2) concentration have an important impact on rice growth and yield. However, many of the current studies that predict the impact of future climate change on rice yield are affected by uncertainties such as climate models, climate scenarios, model parameters and structure, and showing great differences. This study was based on the assessment results of the impact of climate change on rice in the future of 111 published literature, and comprehensively analyzed the impact and uncertainty of climate change on rice yield. This study utilized local polynomial (Loess) regression analysis to investigate the impact of changes in mean temperature, minimum temperature, maximum temperature, solar radiation, and precipitation on relative rice yield variations within a complete dataset. A linear mixed-effects model was used to quantitatively analyze the relationships between the restricted datasets. The qualitative analysis based on the entire dataset revealed that rice yields decreased with increasing average temperature. The precipitation changed between 0 and 25 %, it was conducive to the stable production of rice, and when the precipitation changed >25 %, it would cause rice yield reduction. The change of solar radiation was less than -1.15 %, the rice yield increases with the increase of solar radiation, and when the change of solar radiation exceeds -1.15 %, the rice yield decreases. Elevated CO2 concentrations and management practices could mitigate the negative effects of climate change. The results of a quantitative analysis utilizing the mixed effects model revealed that average temperature, precipitation, CO2 concentration, and adaptation methods all had a substantial impact on rice production, and elevated CO2 concentrations and management practices could exert positive influences on rice production. For every 1 °C and 1 % increase in average temperature and precipitation, rice yield decreased by 3.85 % and 0.56 %, respectively. For every 100 ppm increase in CO2 concentration, rice yield increased by 7.1 %. The variation of rice yield under different climate models, study sites and climate scenarios had significant variability. Elevated CO2 concentrations and management practices could compensate for the negative effects of climate change, benefiting rice production. This study comprehensively collected and analyzed a wide range of literature and research, which provides an in-depth understanding of the impacts of climate change on rice production and informs future research and policy development.


Assuntos
Mudança Climática , Produtos Agrícolas , Oryza , Oryza/crescimento & desenvolvimento , Produtos Agrícolas/crescimento & desenvolvimento , Dióxido de Carbono/análise , Modelos Climáticos , Temperatura , Agricultura/métodos
18.
Food Chem X ; 19: 100807, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37780243

RESUMO

This study evaluated the effects of hot air drying (HAD), microwave drying (MD), vacuum drying (VD), sun drying (SD) and vacuum freeze drying (VFD) on the physical properties, bioactive components, antioxidant capacity, volatile components and industrial application of coffee peel. The results showed VFD could retain the appearance color, total phenolics (19.49 mg GAE/g DW), total flavonoids (9.65 mg CE/g DW), caffeine (3.15 mg/g DW), trigonelline (2.71 mg/g DW), and antioxidant capacities of fresh sample to the greatest extent, but its operating cost was significantly higher than other treatments and total volatile components were in the minimum levels. HAD and SD exhibited the highest loss rates of total phenols and antioxidant capacities, exceeding 50%. MD offered the lowest operating cost, superior retention of bioactive components, and the richest variety and quantity of volatile compounds. Therefore, it is recommended to use MD to dehydrate the coffee peel in actual production.

19.
Int J Biol Macromol ; 224: 1412-1422, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36550790

RESUMO

Superelastic silk fibroin (SF)-based aerogels can be used as multifunctional substrates, exhibiting a promising prospect in air filtration, thermal insulation, and biomedical materials. However, fabrication of the superelastic pure SF aerogels without adding synthetic polymers remains challenging. Here, the SF micro-nano fibrils (SMNFs) that preserved mesostructures are extracted from SF fibers as building blocks of aerogels by a controllable deep eutectic solvent liquid exfoliation technique. SMNFs can assemble into multiscale fibril networks during the freeze-inducing process, resulting in all-natural SMNF aerogels (SMNFAs) with hierarchical cellular architectures after lyophilization. Benefiting from these structural features, the SMNFAs demonstrate desirable properties including ultra-low density (as low as 4.71 mg/cm3) and superelasticity (over 85 % stress retention after 100 compression cycles at 60 % strain). Furthermore, the potential applications of superelastic SMNFAs in air purification and thermal insulation are investigated to exhibit their functionality, mechanical elasticity, and structural stability. This work provides a reliable approach for the fabrication of highly elastic SF aerogels and endows application prospects in air purification and thermal insulation opportunities.


Assuntos
Fibroínas , Seda , Fibroínas/química , Solventes Eutéticos Profundos , Géis/química , Materiais Biocompatíveis
20.
Sci Total Environ ; 880: 163025, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-36966824

RESUMO

The presence of surfactants in waste activated sludge (WAS) system is generally regarded as beneficial to sludge treatment such as enhancing sludge dewatering and improving value-added fermentation products generation. However, in this study, it was firstly found that sodium dodecylbenzene sulfonate (SDBS, a typical surfactant) obviously increased toxic hydrogen sulfide (H2S) gas production from WAS anaerobic fermentation at environmentally relevant concentrations. Experimental results showed that H2S production from WAS significantly increased from 53.24 × 10-3 to 111.25 × 10-3 mg/g volatile suspended solids (VSS) when SDBS level increased from 0 to 30 mg/g total suspended solid (TSS). It was found that SDBS presence destroyed WAS structure and enhanced sulfur containing organics release. SDBS reduced the proportion of α-helix structure, damaged disulfide bridges and protein conformation, and effectively destroyed protein structure. SDBS promoted sulfur containing organics degradation and provided more readily hydrolyzed micro-molecule organics for sulfide production. Microbial analysis showed that SDBS addition enhanced the abundance of functional genes encoding protease, ATP-binding cassette transporters, and amino acids lyase, enhanced the activities and abundance of hydrolytic microbes, thus increased sulfide production from the hydrolysis of sulfur containing organics. Compared with the control, 30 mg/g TSS SDBS increased organic sulfurs hydrolysis and amino acids degradation by 47.1 % and 63.5 %, respectively. Key genes analysis further showed that SDBS addition promoted sulfate transport system and dissimilatory sulfate reduction. SDBS presence also lowered fermentation pH, promoted the chemical equilibrium transformation of sulfide, thus increased H2S gas release.


Assuntos
Sulfeto de Hidrogênio , Microbiota , Fermentação , Esgotos/química , Tensoativos/química , Ácidos Graxos Voláteis , Anaerobiose , Sulfetos , Lipoproteínas , Enxofre , Aminoácidos , Sulfatos , Concentração de Íons de Hidrogênio , Hidrogênio
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