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1.
J Environ Radioact ; 275: 107430, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38615506

RESUMO

Clay colloids in the subsurface environment have a strong adsorption capacity for radionuclides, and the mobile colloids will carry the nuclides for migration, which would promote the movability of radionuclides in the groundwater environment and pose a threat to the ecosphere. The investigations of the adsorption/desorption behaviors of radionuclides in colloids and porous media are significant for the evaluation of the geological disposal of radioactive wastes. To illustrate the adsorption/desorption behaviors of 241Am(Ⅲ) in Na-montmorillonite colloid and/or quartz sand systems at different pH (5, 7 and 9), ionic strengths (0, 0.1 and 5 mM), colloid concentrations (300 and 900 mg/L), nuclide concentrations (500, 800, 1100 and 1400 Bq/mL) and grain sizes (40 and 60 mesh), a series of batch sorption-desorption experiments were conducted. Combining the analysis of the physical and chemical properties of Na-montmorillonite with the Freundlich model, the influencing mechanism of different controlling factors is discussed. The experimental results show that the adsorption/desorption behaviors of 241Am(Ⅲ) in Na-montmorillonite colloid and/or quartz sand strongly are influenced by the pH value and ionic strength of a solution, the colloid concentration as well as quartz sand grain size. The adsorption and desorption isotherms within all the experimental conditions could be well-fitted by the Freundlich model and the correlation coefficients (R2) are bigger than 0.9. With the increase in pH, the adsorption partition coefficient (Kd) at 241Am(Ⅲ)-Na-montmorillonite colloid two-phase system and 241Am(Ⅲ)-Na-montmorillonite colloid-quartz sand three-phase system presents a trend which increases firstly followed by decreasing, due to the changes in the morphology of Am with pH. The Kd of 241Am(Ⅲ) adsorption on montmorillonite colloid and quartz sand decreases with increasing in ionic strength, which is mainly attributed to the competitive adsorption, surface complexation and the reduction of surface zeta potential. Additionally, the Kd increases with increasing colloid concentrations because of the increase in adsorption sites. When the mean grain diameter changes from 0.45 to 0.3 mm, the adsorption variation trends of 241Am(Ⅲ) remain basically unchanged. The research results obtained in this work are meaningful and helpful in understanding the migration behaviors of radionuclides in the underground environment.


Assuntos
Amerício , Bentonita , Coloides , Quartzo , Bentonita/química , Concentração Osmolar , Adsorção , Concentração de Íons de Hidrogênio , Coloides/química , Quartzo/química , Amerício/química , Amerício/análise , Poluentes Radioativos da Água/química , Poluentes Radioativos da Água/análise , Poluentes Radioativos do Solo/análise , Poluentes Radioativos do Solo/química , Modelos Químicos , Tamanho da Partícula , Areia/química
2.
Sci Total Environ ; 927: 172294, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38593882

RESUMO

Biochar colloids entering the soil undergo aging over time and exhibit strong capabilities in adsorbing and transporting pollutants. Therefore, investigating the cotransport of aged biochar colloids and thallium (Tl(I)) in quartz sand media is crucial for understanding Tl(I) migration in underground environments. This study investigated the migration of biochar colloids with two different aging degrees and Tl(I) in quartz sand media at various pH and ionic strengths (ISs). The results revealed that under all ISs and pH, 30%AWB (biochar aged with 30 % (w/w) HNO3) inhibited Tl(I) migration in media. This inhibition primarily arose from the introduction of hydroxyl and carboxyl groups during aging, which significantly enhanced colloid adsorption onto Tl(I). At lower ISs, 30%AWB colloids exhibited greater inhibition of Tl(I) migration due to their increased adsorption capacity. Additionally, aging promoted the migration of biochar colloids in the media. Greater biochar aging notably enhanced this promotion, potentially owing to reduced colloidal particle size and the formation of biochar derivatives. Moreover, 50%AWB (biochar aged with 50 % (w/w) HNO3) inhibited Tl(I) migration under low ISs but had almost no impact under high ISs. Nonetheless, at high pH, 50%AWB colloids facilitated Tl(I) migration. This phenomenon might be attributed to the inhibitory effect of aged biochar colloids on Tl(I) adsorption onto media at a high pH, as well as the stable binding between Tl(I) and aged biochar colloids. This study discusses the cotransport of biochar with various degrees of aging and Tl(I) in media, providing insights into remediating soils contaminated with Tl.


Assuntos
Carvão Vegetal , Coloides , Tálio , Carvão Vegetal/química , Concentração de Íons de Hidrogênio , Coloides/química , Concentração Osmolar , Adsorção , Porosidade , Modelos Químicos
3.
Nature ; 628(8009): 771-775, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38632399

RESUMO

Quantitative detection of various molecules at very low concentrations in complex mixtures has been the main objective in many fields of science and engineering, from the detection of cancer-causing mutagens and early disease markers to environmental pollutants and bioterror agents1-5. Moreover, technologies that can detect these analytes without external labels or modifications are extremely valuable and often preferred6. In this regard, surface-enhanced Raman spectroscopy can detect molecular species in complex mixtures on the basis only of their intrinsic and unique vibrational signatures7. However, the development of surface-enhanced Raman spectroscopy for this purpose has been challenging so far because of uncontrollable signal heterogeneity and poor reproducibility at low analyte concentrations8. Here, as a proof of concept, we show that, using digital (nano)colloid-enhanced Raman spectroscopy, reproducible quantification of a broad range of target molecules at very low concentrations can be routinely achieved with single-molecule counting, limited only by the Poisson noise of the measurement process. As metallic colloidal nanoparticles that enhance these vibrational signatures, including hydroxylamine-reduced-silver colloids, can be fabricated at large scale under routine conditions, we anticipate that digital (nano)colloid-enhanced Raman spectroscopy will become the technology of choice for the reliable and ultrasensitive detection of various analytes, including those of great importance for human health.


Assuntos
Coloides , Nanopartículas Metálicas , Prata , Análise Espectral Raman , Análise Espectral Raman/métodos , Coloides/química , Coloides/análise , Prata/química , Prata/análise , Reprodutibilidade dos Testes , Nanopartículas Metálicas/química , Nanopartículas Metálicas/análise , Hidroxilamina/química , Hidroxilamina/análise , Estudo de Prova de Conceito
4.
Sci Total Environ ; 924: 171590, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38485030

RESUMO

The chemical species of trace elements (TEs) in agricultural soils is highly variable under diverse conditions, requiring tools with clear resolution and minimal disturbance for exploration. A novel surgical (316L) stainless steel (SS) lysimeter with a 5 µm pore size was developed to collect field soil solutions. The size-resolved distribution of TEs were characterized into total (nitric acid digestion), particulate (0.45-5 µm), dissolved (<0.45 µm), colloidal (1 kDa to 0.45 µm), and mainly ionic (<1 kDa) fractions in the lysimeter soil solutions. Total concentrations of TEs (dry weight basis) in acid digested Gray Luvisolic soils were analyzed. Most TEs in lysimeter soil solutions were present in particulate phases, relevant to their geochemical affinities and occurrences in soil minerals. Among dissolved fractions, As, Ba, Co, Li, Mn, Tl, and V existed as mainly ionic species in the soil solutions. Copper, Pb, Al, Th, and U showed variable associations with dissolved organic matter (DOM) and/or inorganic colloids among agricultural treatments. Inorganic NPKS or NKS fertilizer applications with lower pH (5.25-5.74) enhanced mobility and potential bioavailability of Ba, Co, Li, Mn, and Pb present in mainly ionic species, compared with other locations (pH 5.82-6.37). Manure application exhibited a dual effect, potentially increasing bioavailability for As, Tl, and V due to probably enhanced cation exchange capacity (CEC), while also facilitating specific adsorption of Cu and U on DOM, potentially reducing their bioavailability depending on DOM molecular weight. Colloidal and ionic Al and Th concentrations were higher in forest soils than agricultural soils, with extremely low potential bioavailability of Th attributed to strong precipitation with inorganic colloids and adsorption on DOM. The lysimeter sampling and size fractionation method provided a clear insight into agricultural effects on TE distributions and enhancing understanding of agricultural soil health in terms of TE bioavailability in situ.


Assuntos
Poluentes do Solo , Oligoelementos , Oligoelementos/análise , Solo/química , Disponibilidade Biológica , Chumbo , Minerais , Coloides/química , Poluentes do Solo/análise
5.
Food Chem ; 444: 138636, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38310781

RESUMO

Rapidly digestible starch can increase postprandial blood sugar rapidly, which can be overcome by hydrocolloids. The paper aims to review the effect of hydrocolloids on starch digestion. Hydrocolloids used to reduce starch digestibility are mostly polysaccharides like xanthan gum, pectin, ß-glucan, and konjac glucomannan. Their effectiveness is related to their source and structure, mixing mode of hydrocolloid/starch, physical treatment, and starch processing. The mechanisms of hydrocolloid action include increased system viscosity, inhibition of enzymatic activity, and reduced starch accessibility to enzymes. Reduced starch accessibility to enzymes involves physical barrier and structural orderliness. In the future, physical treatments and intensity used for stabilizing hydrocolloid/starch complex, risks associated with different doses of hydrocolloids, and the development of related clinical trials should be focused on. Besides, investigating the effect of hydrocolloids on starch should be conducted in the context of practical commercial applications rather than limited to the laboratory level.


Assuntos
Coloides , Amido , Amido/química , Coloides/química , Pectinas , Digestão , Viscosidade
6.
Food Funct ; 15(4): 1977-1993, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38277180

RESUMO

The present study is designed to study the efficiency of plant-based hydrocolloids for the efficient clarification of sugarcane juice and subsequent production of non-centrifugal sugars (NCSs). NCSs are generally produced with lime or other inorganic solids as a clarification agent, often leading to products with a bland taste and dark color. This work is a first of its kind, where plant-based hydrocolloids such as starch, xanthan gum, and guar gum are used for clarification studies. Clarification efficiency was evaluated in terms of separation efficiency, turbidity removal, sucrose content, color transmittance, and rheology studies. Preliminary studies revealed that starch showed a better separation efficiency of 78% compared to other hydrocolloids, and further rheology studies of starch-clarified juice showed a favourable shear-thickening (dilatant, n = 1.382) behaviour, whereas the other two hydrocolloids showed an unfavourable shear-thinning (pseudo plastic, n < 0.9) behaviour. Eventually, starch was found to be a better clarification agent and is proposed as an alternative to lime-based clarification. Solidification studies were performed with starch at various concentrations (0.02-0.04%), pH (6.8-7.2), and temperature (80 °C-100 °C), and it was found that NCSs produced via starch clarification showed superior properties compared with traditional lime-based clarification processes.


Assuntos
Compostos de Cálcio , Bengala , Coloides , Óxidos , Coloides/química , Polissacarídeos Bacterianos/química , Amido/química , Reologia , Viscosidade
7.
Proc Natl Acad Sci U S A ; 121(5): e2305770121, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38227645

RESUMO

Acylated peptides composed of glucagon-like peptide-1 receptor agonists modified with a fatty acid side chain are an important class of therapeutics for type 2 diabetes and obesity but are susceptible to an unusual physical instability in the presence of hydrophobic surfaces, i.e., spontaneous emulsification, also known as ouzo formation in practice. In this work, light scattering, small-angle X-ray scattering, and circular dichroism measurements are used to characterize the physical properties of the semaglutide colloidal phase, including size distribution, shape, secondary structure, internal structure, and internal composition, as a function of solution physico-chemical conditions. The existence and size of the colloids formed are successfully predicted by a classical Rayleigh model, which identifies the parameters controlling their size and formation. Colloid formation is found to be catalyzed by hydrophobic surfaces, and formation rates are modeled as an autocatalytic reaction, enabling the formation of a master curve for various surfaces that elucidates the mechanism. Surfaces differ due to differences in surface wettability, which can be correlated with Hansen solubility parameters. This work provides insights into this unusual colloidal phenomenon and guides the peptide synthesis process and drug product formulation in the pharmaceutical industry.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Peptídeos Semelhantes ao Glucagon , Molhabilidade , Peptídeos , Coloides/química , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Hipoglicemiantes
8.
Artif Organs ; 48(2): 117-129, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37909148

RESUMO

BACKGROUND: Functionalization of wound dressing is one of the main approaches for promoting wound healing in skin wound management. In this study, our aim is to fabricate a bio-functionalized hydrocolloid wound dressing. METHODS: The extracellular matrix (ECM) was extracted from human placental tissue. A hydrocolloid film was fabricated using Na-CMC, pectin, gelatin, styrene-isoprene-styrene adhesive, glycerol, and 0.5%-2.5% powdered ECM. A polyurethane film and a release liner were used in the hydrocolloid/ECM films. The mechanical, adhesion, swelling rate, and integrity of the films were investigated. Cell proliferation, adhesion, and migration assays, as well as, SEM and FTIR spectroscopy were also conducted. Macroscopic and microscopic evaluations of wound healing process and formation of blood vessels were conducted in mouse animal models. RESULTS: We successfully fabricated a three-layered ECM-functionalized hydrocolloid dressing with a water vapor transmission rate of 371 g/m2 /day and an adhesion peel strength of 176 KPa. Cellular adhesion, proliferation and migration were promoted by ECM. In the animal tests, ECM-functionalized hydrocolloids significantly improved wound closure and re-epithelialization at days 14 and 21. Also, ECM-functionalized hydrocolloids promoted the formation of hair follicles. CONCLUSIONS: Our findings suggest that ECM could enhance the wound healing properties of hydrocolloid wound dressings. This wound dressing could be considered for application in hard-to-heal acute wounds.


Assuntos
Matriz Extracelular , Placenta , Gravidez , Humanos , Feminino , Camundongos , Animais , Curativos Hidrocoloides , Animais de Laboratório , Coloides/química , Estirenos
9.
Int J Biol Macromol ; 257(Pt 1): 128562, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38056154

RESUMO

In this study, xanthan gum (XG), sodium alginate (SA), guar gum (GG), and gum Arabic (GA), were used to modify Lotus root starch (LRS). The incorporation XG, SA, and GG significantly (p < 0.05) influence the swelling power (SP) of LRS, among which the 1.5 % of XG exhibited the highest value of 25.84 g/g at 90 °C. Gelatinization analysis revealed that XG raised the final viscosity (FV) and lowered the breakdown (BD), while SA significantly increased peak viscosity (PV) and BD. Furthermore, GG and GA exhibited a substantial reduction in setback (SB). The incorporation of XG, SA, and GG enhanced the rheological and structural properties (e.g., gel strength and elasticity) of LRS. Particularly, XG demonstrated a more prominent effect, while GA exhibited an opposite trend. Moreover, the structural analyses revealed that hydrophilic colloids have no impact on the functional group and crystal structure of the LRS. However, complex system exhibited the more stable hydrogen bonding. The addition of 1.5 % XG exhibited the most stable hydrogen bonding and highest water binding affinity. Overall, the results demonstrated the effect of different hydrophilic colloids on LRS, offering a theoretical basis for LRS applications and novel insights for the use of starches and hydrocolloids.


Assuntos
Coloides , Amido , Amido/química , Coloides/química , Géis/química , Polissacarídeos Bacterianos/química , Goma Arábica/química , Viscosidade , Reologia
10.
ACS Appl Bio Mater ; 7(2): 535-542, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-36698242

RESUMO

Colloids with lobed architectures have been shown to self-assemble into promising porous structures with potential biomedical applications. The synthesis of these colloids via experiments can be tuned to vary the number and the position of the lobes. However, the polydispersity involving the numbers, sizes, and the dispositions of lobes, that is often observed in particle designs, can significantly affect their self-assembled structures. In this work, we go beyond the uniform lobe size conditions commonly considered in molecular simulations, and probe the effect of polydispersity due to non-uniform lobe sizes by studying self-assembly in three experimentally observable designs of lobed particles (dumbbell, two lobes; trigonal planar, three lobes; and tetrahedral, four lobes), using coarse-grained Langevin dynamics simulations in the NVT ensemble. With increasing polydispersity, we observed the formation of a crystalline structure from a disordered state for the dumbbell system, and a loss of order in the crystalline structures for the trigonal planar system. The tetrahedral system retained a crystalline structure with only a minor loss in compactness. We observed that the effect of polydispersity on the self-assembled morphology of a given system can be minimized by increasing the number of lobes. The polydispersity in the lobe size may also be useful in tuning self-assemblies toward desired structures.


Assuntos
Coloides , Coloides/química
11.
Faraday Discuss ; 249(0): 408-423, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-37791509

RESUMO

Colloidal crystals have applications in water treatments, including water purification and desalination technologies. It is, therefore, important to understand the interactions between colloids as a function of electrolyte concentration. We study the assembly of DNA-grafted gold nanoparticles immersed in concentrated electrolyte solutions. Increasing the concentration of divalent Ca2+ ions leads to the condensation of nanoparticles into face-centered-cubic (FCC) crystals at low electrolyte concentrations. As the electrolyte concentration increases, the system undergoes a phase change to body-centered-cubic (BCC) crystals. This phase change occurs as the interparticle distance decreases. Molecular dynamics analysis suggests that the interparticle interactions change from strongly repulsive to short-range attractive as the divalent-electrolyte concentration increases. A thermodynamic analysis suggests that increasing the salt concentration leads to significant dehydration of the nanoparticle environment. We conjecture that the intercolloid attractive interactions and dehydrated states favour the BCC structure. Our results gain insight into salting out of colloids such as proteins as the concentration of salt increases in the solution.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Coloides/química , DNA/química , Eletrólitos/química , Ouro/química , Nanopartículas/química , Cálcio/química
12.
Macromol Rapid Commun ; 45(8): e2300696, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38160322

RESUMO

Controlling the internal structure of block copolymer (BCP) particles has a significant influence on its functionalities. Here, a structure-controlling method is proposed to regulate the internal structure of BCP Janus colloidal particles using different surfactants. Different microphase separation processes take place in two connected halves of the Janus particles. An order-order transition between gyroid and lamellar phases is observed in polymeric colloids. The epitaxial growth during the structural transformation from gyroid to lamellar phase undergoes a two-layered rearrangement to accommodate the interdomain spacing mismatch between these two phases. This self-assembly behavior can be ascribed to the preferential wetting of BCP chains at the interface, which can change the chain conformation of different blocks. The Janus colloidal particles can further experience a reversible phase transition by restructuring the polymer particles under solvent vapor. It is anticipated that the new phase behavior found in Janus particles can not only enrich the self-assembly study of BCPs but also provide opportunities for various applications based on Janus particles with ordered structures.


Assuntos
Coloides , Polímeros , Coloides/química , Polímeros/química , Tamanho da Partícula , Propriedades de Superfície , Tensoativos/química , Transição de Fase , Estrutura Molecular
13.
Nature ; 626(7999): 542-548, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38109940

RESUMO

The success of colloidal semiconductor nanocrystals (NCs) in science and optoelectronics is inextricable from their surfaces. The functionalization of lead halide perovskite NCs1-5 poses a formidable challenge because of their structural lability, unlike the well-established covalent ligand capping of conventional semiconductor NCs6,7. We posited that the vast and facile molecular engineering of phospholipids as zwitterionic surfactants can deliver highly customized surface chemistries for metal halide NCs. Molecular dynamics simulations implied that ligand-NC surface affinity is primarily governed by the structure of the zwitterionic head group, particularly by the geometric fitness of the anionic and cationic moieties into the surface lattice sites, as corroborated by the nuclear magnetic resonance and Fourier-transform infrared spectroscopy data. Lattice-matched primary-ammonium phospholipids enhance the structural and colloidal integrity of hybrid organic-inorganic lead halide perovskites (FAPbBr3 and MAPbBr3 (FA, formamidinium; MA, methylammonium)) and lead-free metal halide NCs. The molecular structure of the organic ligand tail governs the long-term colloidal stability and compatibility with solvents of diverse polarity, from hydrocarbons to acetone and alcohols. These NCs exhibit photoluminescence quantum yield of more than 96% in solution and solids and minimal photoluminescence intermittency at the single particle level with an average ON fraction as high as 94%, as well as bright and high-purity (about 95%) single-photon emission.


Assuntos
Desenho de Fármacos , Ligantes , Nanopartículas Metálicas , Pontos Quânticos , Acetona/química , Álcoois/química , Ânions , Compostos de Cálcio/química , Cátions , Coloides/química , Chumbo , Medições Luminescentes , Espectroscopia de Ressonância Magnética , Nanopartículas Metálicas/química , Simulação de Dinâmica Molecular , Óxidos/química , Fosfolipídeos/química , Pontos Quânticos/química , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/química
14.
Environ Pollut ; 343: 123197, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38128710

RESUMO

The diversity of colloidal types and the differences in the composite ratios in porous media are important factors governing the migration and biological risk of pathogenic microorganisms in the subsurface environment. In this study, E. coli O157:H7 was subjected to co-migration experiments with different compositions of the composite colloid montmorillonite (MMT)-Fe2O3, and the biomolecular response of E. coli under the action of colloids was analyzed by Raman spectroscopy to quantify the risk of E. coli under the action of composite colloids based on both. The results showed that Fe2O3 colloids inhibited E. coli migration mainly by electrostatic adsorption and reduced E. coli metabolism. MMT colloid inhibited E. coli migration mainly by blockage, and E. coli metabolism increased, and surface macromolecules decreased to reduce E. coli adhesion. MMT-Fe2O3 complex colloids inhibited migration through electrostatic attraction between the two and formation of cohesive colloids, with reduced E. coli metabolism and insignificant biomolecular response. It was briefly assessed that the composite colloids reduced E. coli risk less strongly than single colloids, stemming from the difference in the mechanism of influence and the actual need to consider colloid interactions. This conclusion can inform the management and control of pathogen risk in porous media environments.


Assuntos
Bentonita , Escherichia coli , Porosidade , Bentonita/química , Coloides/química , Adsorção
15.
Environ Pollut ; 343: 123204, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38142807

RESUMO

Colloid-facilitated phosphorus (P) migration plays an important role in P loss from farmland to adjacent water bodies. However, the dynamics of colloidal P (Pcoll) release as influenced by irrigation in alkaline calcareous soil remains a knowledge gap. The present study, monitored the dynamic change of Pcoll under different water management strategies: 1) control, 2) flooding, and 3) alternating flooding and drying cycles. Soil water-dispersible colloids (0.6 nm-1 µm) were extracted by combining filtration and ultrafiltration methods. The contents of P, cation and organic carbon in the water-dispersible colloids were determined and the stability and mineral composition of colloidal fractions were characterized. The results showed that Pcoll ranged from 16.5 to 25.5 mg kg-1 and represented 42.8%-64.9% of the water-extracted P in the control. Flooding significantly decreased the Pcoll content by 16.0%-62.1% (mean 32.7%) and it may be attributed to the dissolution of colloidal iron (Fe) bound P. The alternating flooding and drying treatment significantly reduced the Pcoll content by 11.6%-88.0% (mean 67.6%). The Pcoll content of the flooding event was always greater than the Pcoll content of the drying event during flooding and drying cycles. Redundancy analysis and random forest modeling showed that the colloidal calcium (Ca) and ionic strength in soil solutions had negative correlations with the Pcoll content, and pH, ionic strength and truly dissolved P were the critical factors affecting Pcoll. Drying of the flooded soil led to the decrease of pH and the increase of ionic strength, colloidal Ca content and positive charges of colloid surfaces, which promoted colloid aggregation and enhanced soil P sorption capacity. This restricted the loss potential of Pcoll. In summary, controlled flooding and drainage when managed correctly have a role to play in mitigating Pcoll loss from P-enriched calcareous soils.


Assuntos
Fósforo , Solo , Fósforo/análise , Solo/química , Água/química , Inundações , Coloides/química
16.
Soft Matter ; 19(45): 8779-8789, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37942543

RESUMO

DNA-coated colloids can crystallize into a multitude of lattices, ranging from face-centered cubic to diamond, opening avenues to producing structures with useful photonic properties. The potential design space of DNA-coated colloids is large, but its exploration is hampered by a reliance on chemically modified DNA that is slow and expensive to commercially synthesize. Here we introduce a method to controllably tailor the sequences of DNA-coated particles by covalently appending new sequence domains onto the DNA grafted to colloidal particles. The tailored particles crystallize as readily and at the same temperature as those produced via direct chemical synthesis, making them suitable for self-assembly. Moreover, we show that particles coated with a single sequence can be converted into a variety of building blocks with differing specificities by appending different DNA sequences to them. This method will make it practical to identify optimal and complex particle sequence designs and paves the way to programming the assembly kinetics of DNA-coated colloids.


Assuntos
Coloides , DNA , DNA/química , Coloides/química , Temperatura , Cinética
17.
J Indian Prosthodont Soc ; 23(3): 294-300, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37929369

RESUMO

Aim: The aim was to compare the efficacy of various herbal disinfectants on irreversible hydrocolloid impressions and to investigate the effectiveness of three herbal disinfectants and a chemical disinfectant against particular pathogens. Settings and Design: In vitro -a comparative study. Materials and Methods: The following methodology was followed to achieve the objectives. Four maxillary impressions were made for each selected patient with irreversible hydrocolloid impression material. The predisinfection swabs were taken from impression sites of teeth 17, 13, 27, and 23 (FDI system of tooth numbering). The impressions were immersed in all four different disinfectants such as 2% glutaraldehyde, Aloe vera solution, 50% neem oil, and apple vinegar solution, then the postdisinfection swabs were taken from the same sites 17,13,27,23 and then cultured onto sheep blood agar and examined for growth, and colony forming units (CFUs) of Streptococcus viridans, Streptococcus mutans, Streptococcus sanguis, and Actinomyces viscosus. The comparative analysis was done for the predisinfection and postdisinfection values in each study group. Statistical Analysis Used: Descriptive analysis, Kruskal Wallis test, Mann Whitney post hoc test, Wilcoxon signed rank test. Results: The results revealed that the mean CFUs of S. viridans, S. mutans, S. sanguis, and A. viscosus during postdisinfection samples were statistically significant when compared to predisinfection samples. Multiple comparison of the mean CFUs of all 4 microorganisms in the control group and in 50% Neem oil group was significantly lesser compared to A. vera and Apple Vinegar group. Conclusion: CFUs of S. viridans, S. mutans, S. sanguis, and A. viscosus significantly decreased in the 50% neem oil group as well as the control group. As a result, 50% Neem oil was a viable option for disinfecting alginate impressions.


Assuntos
Anti-Infecciosos , Desinfetantes , Humanos , Desinfetantes/farmacologia , Ácido Acético , Anti-Infecciosos/química , Coloides/química
18.
Environ Sci Technol ; 57(43): 16564-16574, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37862689

RESUMO

The bioavailability for varied-size phosphorus (P)-binding colloids (Pcoll) especially from external P sources in soil terrestrial ecosystems remains unclear. This study evaluated the differential contribution of various-sized biogas slurry (BS)-derived colloids to plant available P uptake in the rhizosphere and the corresponding patterns of phosphatase response. Keeping the same content of total P input (15 mg kg-1), we applied different size-fractioned BS-derived colloids including nanosized colloids (NCs, 1-20 nm), fine-sized colloids (FCs, 20-220 nm), and medium-sized colloids (MCs, 220-450 nm) respectively to conduct a 45-day rice (Oryza sativa L.) rhizotron experiment. During the whole cultivation period, the dynamics of chemical characteristics and P fractions in each experimental rhizosphere soil solution were analyzed. The spatial and temporal dynamics examination of P-transforming enzymes (acid phosphatases) in the rice rhizosphere was visualized by a soil zymography technique after 5, 25, and 45 days of rice transplantation. The results indicated that the acid phosphatase activities and its hot spot areas were significantly 1) correlated with the relative bioavailability of colloidal P (RBAcoll), 2) increased with the colloid-free (truly dissolved P) and BS-derived NC addition, and 3) affected by the plant growth stage. With the nanosized BS colloid addition, the RBAcoll and plant biomass were respectively found to be the highest (64% and 1.22 g plant-1), in which the acid phosphatase-catalyzed hydrolysis of organic Pcoll played an important role. All of the above suggested that nanosized BS-derived colloids are an effective alternative to conventional phosphorus fertilizer for promoting plant P uptake and P bioavailability.


Assuntos
Biocombustíveis , Oryza , Monoéster Fosfórico Hidrolases , Ecossistema , Solo/química , Coloides/química , Fertilizantes , Fósforo , Fosfatase Ácida
19.
J Oleo Sci ; 72(9): 819-829, 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37574284

RESUMO

Oleofoams have garnered significant attention in many personal care applications because of their favorable physicochemical properties, including texture and detergency. To explore the potential use of mixtures of high-melting-point fat crystals (tribehenoyl-glycerol [BBB]) and edible oils as low-cost and stable aeration systems, we created oleofoams composed of olive oil and BBB. By whipping the BBB/olive oil oleogels after rapid cooling and subsequent heating, we successfully prepared oleofoams without emulsifier additives. Mixtures of the BBB/olive oil formed oleofoams at BBB concentrations of 4.0-20.0 wt.%. The resultant oleofoams maintained their overrun rates and did not coalesce, even with additional whipping after the overrun rate was maximized. More closely packed bubbles, concentrated bubble size distributions, and stronger interfacial elasticity were attributed to the increasing BBB concentrations, and the thermal results revealed that further heating was required to damage the foam structure. The characteristics of these new oleofoams are closely related to their BBB concentrations, and the observed effects are attributed to the network structure of the thickened crystal layer and enhanced gelling in the oil phase.


Assuntos
Glicerol , Coloides/química , Glicerol/química , Azeite de Oliva/química , Reologia
20.
Int J Biol Macromol ; 249: 126098, 2023 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-37543265

RESUMO

Hydrocolloids are important ingredients in food formulations and their modification can lead to novel ingredients with unique functionalities beyond their nutritional value. Cold plasma is a promising technology for the modification of food biopolymers due to its non-toxic and eco-friendly nature. This review discusses the recent published studies on the effects of cold plasma treatment on non-starch hydrocolloids and their derivatives. It covers the common phenomena that occur during plasma treatment, including ionization, etching effect, surface modification, and ashing effect, and how they contribute to various changes in food biopolymers. The effects of plasma treatment on important properties such as color, crystallinity, chemical structure, rheological behavior, and thermal properties of non-starch hydrocolloids and their derivatives are also discussed. In addition, this review highlights the potential of cold plasma treatment to enhance the functionality of food biopolymers and improve the quality of food products. The mechanisms underlying the effects of plasma treatment on food biopolymers, which can be useful for future research in this area, are also discussed. Overall, this review paper presents a comprehensive overview of the current knowledge in the field of cold plasma treatment of non-starch hydrocolloids and their derivatives and highlights the areas that require further investigation.


Assuntos
Gases em Plasma , Polissacarídeos , Coloides/química , Biopolímeros , Alimentos
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