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1.
Environ Res ; 232: 116225, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37247652

RESUMEN

Continuous straw returning is widely encouraged for augmenting soil organic carbon (SOC) in arable lands. However, the magnitude of changes in net SOC related to native SOC mineralization and new SOC development upon fresh straw incorporation remains elusive, particularly in soils after continuous straw returning with different strategies. To address this, soil that had undergone nine years of straw returning with different strategies (NS, non-straw returning; DS, direct straw returning; IS, indirect straw returning) was incubated with fresh 13C-labeled straw for 45 days. Fresh straw incorporation stimulated native SOC-derived CO2 emission in DS soil, which in turn promoted straw-derived CO2 emission in IS soil. Overall, the amounts of newly developed SOC from straw (2.41-2.59 g C/kg soil) overcompensated for the native SOC losses (0.91-1.37 g C/kg soil) by mineralization, and led to net C sequestration in all treatments. No obvious difference was found in the amounts of SOC sequestrated from straw between the DS and NS soils, while the amount of native SOC mineralization increased by 40-50% in the DS soil relative to other treatments, thus resulting in lower net C sequestration in the DS soil (1.21 g C/kg soil) than IS and NS soil (1.43 and 1.65 g C/kg for IS and NS soil, respectively). Spearman's correlation analyses indicated a significant (p < 0.01) and positive correlation between SOC contents and native soil C mineralization, while the soil microbial index played a greater role in influencing fresh straw sequestration (p < 0.01). In conclusion, the DS soil showed a weaker effect on SOC sequestration than IS after 9 years of practices, upon fresh straw incorporation. This difference may be attributed to the magnitude of native SOC mineralization in the soil. Besides the straw-C input rate, results emphasize that native soil C protection should be also considered in long-term SOC sequestration practices.


Asunto(s)
Carbono , Suelo , Carbono/metabolismo , Agricultura/métodos , Dióxido de Carbono , Secuestro de Carbono
2.
Environ Res ; 212(Pt C): 113423, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35537500

RESUMEN

Earthworm activities not only increase nitrogen (N) uptake by crops, but also lead to N losing to environment. Thus, the present study examined the transformation of 15N-labeled urea with and without earthworms (Metaphire guillelmi) in a soil-lettuce system. We evaluated lettuce 15N uptake, 15N losses including N2O emission, NH3 volatilization and leaching, as well as 15N remaining in soil. Results showed that 15N-urea uptakes by lettuce significantly increased from 33.07% to 42.72% with earthworm presence. However, little difference was found on the total amounts of leaching and gaseous losses (N2O emission and NH3 volatilization) from 15N-urea between the treatment with and without earthworms (4.04 and 5.38%, respectively). Most of the 15N-urea remained in the soil, accounting for 48.44% and 60.65% of the 15N-urea in soil with and without earthworm presence. We conclude that earthworms enhanced the transfer of 15N-urea to lettuce without appreciably increasing the 15N-urea loss from soil to the environment.


Asunto(s)
Oligoquetos , Agricultura/métodos , Animales , Fertilizantes , Lactuca , Nitrógeno/análisis , Suelo , Urea
3.
J Environ Manage ; 250: 109535, 2019 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31525696

RESUMEN

Heavy metals are believed to impact soil processes by influencing microbial communities, nutrient cycling or exchanging for essential plant nutrients. Soil pH adjustment highly influences the bio-availability of nutrients and microbial processes. We examined the effect of soil pH manipulation and copper (Cu as CuCl2.2H2O) application on nitrogen (N) cycling and nitrous oxide (N2O) emissions from an acid soil. Increasing amounts of Cu (0, 250, 500 and 1000 mg kg-1) were added to an acidic soil (pH = 5.44) that was further amended with increasing amounts of dolomite [CaMg(CO3)2] to increase soil pH. Dolomite increased soil pH values, which reached a maximum without Cu application (-Cu) at day 42 of the experiment. The soil pH values decreased with increasing dose of Cu, and remained low as compared with both control and dolomite amended soil. Ammonium (NH4+-N) concentrations were higher in Cu contaminated soil as compared with the control and dolomite treated soil. Nitrate (NO3--N) concentrations increased in dolomite treated soil when compared with the +Cu alone treatments and control. Microbial biomass carbon (MBC) and nitrogen (MBN) contents were higher in dolomite treated soil as compared with the +Cu treatments and control. The application of increasing amounts of Cu progressively decreased soil MBC and MBN. Nitrous oxide emissions were higher (p ≤ 0.01) in +Cu soil as compared with the control, and increased with increasing Cu concentration in soil. Application of dolomite highly suppressed soil N2O emissions in both +Cu and -Cu soils. The results indicate that the effects of heavy metal contamination (specifically Cu contamination) can increase N2O emissions, but this can be effectively mitigated through increasing soil pH, also decreasing potential toxic effects on soil microorganisms.


Asunto(s)
Óxido Nitroso , Suelo , Ácidos , Carbono , Fertilizantes , Nitrógeno
4.
Anal Bioanal Chem ; 408(21): 5801-5809, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27311954

RESUMEN

The food safety supervision in aquatic products has raised public concern in recent years. In this study, a liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for the simultaneous quantification and identification of four residues of the ever widely used analytes (including malachite green, leucomalachite green, diethylstilbestrol, and dienestrol) in aquaculture samples was developed. For sample preparation, a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used, which was initially developed for pesticide residue analysis. For cleanup procedure, low-temperature cleanup method was combined with multiplug filtration cleanup (m-PFC) method based on multi-walled carbon nanotubes (MWCNTs). The volume of water, extraction solvent, cleanup sorbents, and m-PFC procedure were optimized for carp, striped bass, and giant salamander matrices. It was validated by analyzing four residues in each matrix spiked at three concentration levels of 0.5, 5, and 50 µg/kg (n = 5). The method was successfully validated according to the 2002/657/EC guidelines. After optimization, spike recoveries were within 73-106 % and <15 % relative standard deviations (RSDs) for all analytes in the tested matrices. Limits of quantification (LOQs) for the proposed method ranged from 0.10 to 0.50 µg/kg. Matrix-matched calibrations were performed with the coefficients of determination >0.998 between concentration levels of 0.5 and 200 µg/kg. The developed method was successfully applied to the determination of residues in market samples. Graphical abstract Flow chart of multi-plug filtration cleanup combined with low-temperature cleanup method.


Asunto(s)
Dietilestilbestrol/análisis , Residuos de Medicamentos/análisis , Contaminación de Alimentos/análisis , Nanotubos de Carbono/química , Colorantes de Rosanilina/análisis , Alimentos Marinos/análisis , Espectrometría de Masas en Tándem/métodos , Animales , Lubina/metabolismo , Carpas/metabolismo , Cromatografía Liquida/métodos , Dienestrol/análisis , Dienestrol/metabolismo , Dietilestilbestrol/metabolismo , Residuos de Medicamentos/metabolismo , Límite de Detección , Colorantes de Rosanilina/metabolismo , Extracción en Fase Sólida/métodos , Urodelos/metabolismo
5.
Nanomedicine ; 12(4): 881-891, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26767513

RESUMEN

Nanotechnology associated with a crystal engineering approach was proposed for improving the solubility and efficacy of hydrophobic drugs in this study. 10-hydroxycamptothecin polymorphic nanoparticle dispersions (HCPT-PNDs) were prepared using the supercritical anti-solvent technique coupled with the high-pressure homogenization method. Shape- and polymorph-dependent tumor suppression was observed in both in vitro and in vivo models, where needle-shaped HCPT-PND exhibited dramatic improvement of antitumor efficacy. A benefit of controllable size and a large surface-to-volume ratio of needle-shaped nanoparticles is the improvement of dissolution properties, which facilitates enhancing pharmacokinetic and pharmaco-dynamic properties. The needle-shaped HCPT-PND, which with longer blood retention time and more effective cellular uptake, makes it possible to accumulate drug in tumor tissues and exhibit higher cytotoxicity. No severe systemic toxicity was observed due to sustained-dissolution and the low dose of drug in normal tissues. The results suggest that the needle-shaped HCPT-PND is an interesting nano-formulation of HCPT. FROM THE CLINICAL EDITOR: Nanotechnology has enabled the production of novel therapeutics drugs against cancer. Here, the authors investigated the use of a crystal engineering approach for the modification of camptothecin in order to improve its water solubility. Physicochemical and biological properties were studied. The results would suggest the applicability of this approach for nano-formulation.


Asunto(s)
Camptotecina/análogos & derivados , Sistemas de Liberación de Medicamentos , Nanopartículas/administración & dosificación , Neoplasias/tratamiento farmacológico , Camptotecina/administración & dosificación , Camptotecina/química , Línea Celular Tumoral , Humanos , Nanopartículas/química , Neoplasias/patología , Tamaño de la Partícula , Solubilidad , Distribución Tisular
6.
Zhongguo Zhong Yao Za Zhi ; 39(5): 807-11, 2014 Mar.
Artículo en Zh | MEDLINE | ID: mdl-25204169

RESUMEN

In our study, 198 types of pesticides in 120 types 333 lots of traditional Chinese medicine (TCM), which were reasonably classified according to its matrix property, were determined by using the pretreatment platform and gas chromatography-mass spectrometry method. As a result, 158 were contaminated with pesticides. However, the content of pesticides in most TCM was very low. In addition, types of pesticides were different in different part of materia medica. In conclusion, the current status of pesticide residues pollutants in TCM was summarized, and the result can provide proof for the formulation of maximum residue limit. The new species of herbs and the new detecting index should be electively monitored in Chinese Pharmacopeia.


Asunto(s)
Contaminación de Medicamentos/prevención & control , Residuos de Plaguicidas/análisis , Plantas Medicinales/química , China , Control de Calidad
7.
Water Res ; 250: 121033, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38142504

RESUMEN

The sudden increase in water nutrients caused by environmental factors have always been a focus of attention for ecologists. Fertilizer inputs with spatio-temporal characteristics are the main contributors to water pollution in agricultural watersheds. However, there are few studies on the thresholds of nitrogen (N) and phosphorus (P) fertilization rates that affect the abrupt deterioration of water quality. This study aims to investigate 28 ponds in Central China in 2019 to reveal the relationships of basal and topdressing fertilization intensities in surrounding agricultural land with pond water N and P concentrations, including total N (TN), nitrate (NO3--N), ammonium (NH4+-N), total P (TP), and dissolved P (DP). Abrupt change analysis was used to determine the thresholds of fertilization intensities causing sharp increases in the pond water N and P concentrations. Generally, the observed pond water N and P concentrations during the high-runoff period were higher than those during the low-runoff period. The TN, NO3--N, TP, DP concentrations showed stronger positive correlations with topdressing intensities, while the NH4+-N concentrations exhibited a higher positive correlation with basal intensities. On the other hand, the NO3--N concentrations had a significant positive correlation with the topdressing N, basal N, and catchment slope interactions. Significant negative correlations were observed between all water quality parameters and pond area. Spatial scale analysis indicated that fertilization practices at the 50 m and 100 m buffer zone scales exhibited greater independent effects on the variations in the N and P concentrations than those at the catchment scale. The thresholds analysis results of fertilization intensities indicated that pond water N concentrations increased sharply when topdressing and basal N intensities exceeded 163 and 115 kg/ha at the 100 and 50 m buffer zone scales, respectively. Similarly, pond water P concentrations rose significantly when topdressing and basal P intensities exceeded 117 and 78 kg/ha at the 50 m buffer zone scale, respectively. These findings suggest that fertilization management should incorporate thresholds and spatio-temporal scales to effectively mitigate pond water pollution.


Asunto(s)
Nitrógeno , Contaminantes Químicos del Agua , Nitrógeno/análisis , Estanques , Monitoreo del Ambiente/métodos , Fósforo/análisis , Contaminantes Químicos del Agua/análisis , Calidad del Agua , China , Fertilización
8.
Eur J Pharm Biopharm ; 196: 114201, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38309538

RESUMEN

Cocrystal engineering, which involves the self-assembly of two or more components into a solid-state supramolecular structure through non-covalent interactions, has emerged as a promising approach to tailor the physicochemical properties of active pharmaceutical ingredient (API). Efficient coformer screening for cocrystal remains a challenge. Herein, a prediction strategy based on machine learning algorithms was employed to predict cocrystal formation and seven reliable models with accuracy over 0.890 were successfully constructed. Imatinib was selected as the model drug and the models established were applied to screen 31 potential coformers. Experimental verification results indicated RF-8 is the optimal model among seven models with an accuracy of 0.839. When the seven models were combined for coformer screening of Imatinib, the combinational model achieved an accuracy of 0.903, and eight new solid forms were observed and characterized. Benefiting from intermolecular interactions, the obtained multicomponent crystals displayed enhanced physicochemical properties. Dissolution and solubility experiments showed the prepared multicomponent crystals had higher cumulative dissolution rate and remarkably improved the solubility of imatinib, and IM-MC exhibited comparable solubility to Imatinib mesylate α form. Stability test and cytotoxicity results showed that multicomponent crystals exhibited excellent stability and the drug-drug cocrystal IM-5F exhibited higher cytotoxicity than pure API.


Asunto(s)
Química Farmacéutica , Mesilato de Imatinib , Cristalización , Química Farmacéutica/métodos , Solubilidad
9.
Biomater Adv ; 165: 214000, 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39208498

RESUMEN

Reasonable optimization of degradation rate, antibacterial performance and biocompatibility is crucial for the development of biodegradable zinc alloy medical implant devices with antibacterial properties. In this study, various amounts of Mg elements were incorporated into Zn5Cu alloy to modulate the degradation rate, antibacterial properties and biocompatibility. The effects of Mg contents on the microstructure, corrosion behavior, antibacterial properties and biocompatibility of Zn-5Cu-xMg alloy were extensively investigated. The results revealed that with an increase of Mg content, the amount of Mg2Zn11 phase increased and its galvanic effect with the Zn matrix was enhanced, which accelerated the corrosion process and led to higher corrosion rate and high degradation rate of the alloy. Additionally, there was an increased release of Mg2+ and Zn2+ ions from the alloy which imparted excellent resistance against Escherichia coli and Staphylococcus aureus bacteria and improved biocompatibility, subcutaneous antibacterial and immune microenvironment regulation properties. Zn-5Cu-2 Mg exhibited superior antibacterial ability, cell compatibility, proliferation effect, subcutaneous antibacterial and immune microenvironment regulation performances, which can work as a promising candidate of biodegradable antibacterial medical implants.

10.
Front Neurosci ; 17: 1256194, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37732310

RESUMEN

In an era of swift societal changes and escalating consumerism, this paper presents an exploration of an innovative approach that integrates product marketing strategies, mixed reality (MR) technology, and affective neuroscience theories to actualize consumers' existential dreams. MR, with its unique capacity to blend the virtual and real worlds, can enhance the consumer experience by creating immersive, personalized environments that resonate with consumers' existential aspirations. Insights from affective neuroscience, specifically the brain's processing of emotions, guide the development of emotionally engaging marketing strategies, which strengthen the connection between consumers, products, and brands. These integrated strategies not only present a novel blueprint for companies to deepen consumer engagement but also promise more fulfilling and meaningful consumer experiences. Moreover, this approach contributes to societal well-being and prosperity, marking a significant stride in the field of marketing.

11.
Pharmaceutics ; 15(9)2023 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-37765145

RESUMEN

Multicomponent solid forms of low molecular weight drugs, such as co-crystals, salts, and co-amorphous systems, are a result of the combination of an active pharmaceutical ingredient (API) with a pharmaceutically acceptable co-former. These solid forms can enhance the physicochemical and pharmacokinetic properties of APIs, making them increasingly interesting and important in recent decades. Nevertheless, predicting the formation of API multicomponent solid forms in the early stages of formulation development can be challenging, as it often requires significant time and resources. To address this, empirical and computational methods have been developed to help screen for potential co-formers more efficiently and accurately, thus reducing the number of laboratory experiments needed. This review provides a comprehensive overview of current screening and prediction methods for the formation of API multicomponent solid forms, covering both crystalline states (co-crystals and salts) and amorphous forms (co-amorphous). Furthermore, it discusses recent advances and emerging trends in prediction methods, with a particular focus on artificial intelligence.

12.
Artículo en Inglés | MEDLINE | ID: mdl-36884340

RESUMEN

Pickering emulsions have received considerable attention for their stability and functionality. Environmentally responsive Pickering emulsions could be used as vehicles for oral administration. However, challenges still exist, such as nonbiocompatibility of emulsifier and mismatched response behavior in the gastrointestinal environment. In this study, a strategy was proposed that bioactive saponin glycyrrhizic acid (GA) was used as a pH-responsive substance to functionalize zein nanoparticles, and tannic acid (TA) was used as a primer for cross-linking GA and zein nanoparticles. The Pickering emulsions fabricated by zein/TA/GA nanoparticles (ZTGs) exhibited excellent stability at acid conditions while slowly demulsifying at neutral conditions, which can be further used as an intestine-targeted delivery system. Curcumin was encapsulated into ZTG-stabilized Pickering emulsions, and the encapsulation efficiency results suggested that the presence of GA coating remarkably facilitated the encapsulation of curcumin. An in vitro digestion study suggested that ZTGs provided protection for emulsions from pepsin hydrolysis and exhibited higher free fatty acid release as well as higher bioaccessibility of curcumin during simulated intestine digestion. This study provides an effective strategy to prepare pH-responsive Pickering emulsions for improving the oral bioaccessibility of hydrophobic nutraceuticals.

13.
Bioresour Technol ; 383: 129240, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37247794

RESUMEN

Improving the activity of ß-xylosidase at high temperature and organic solvents is important for the conversion of xylan, phytochemicals and some hydroxyl-containing substances to produce xylose and bioactive substances. In this study, a ß-xylosidase R333H and an endoxylanase were simultaneously co-immobilized on the metal-organic framework UiO-66-NH2. Compared with the single R333H immobilization system, the co-immobilization enhanced the activity of R333H at high temperature and high concentration of acetone, and the relative activities at 95 °C and 50% acetone solution were >95%. The Km value of co-immobilized R333H towards p-Nitrophenyl-ß-D-xylopyranoside (pNPX) shifted from 2.04 to 0.94 mM, which indicated the enhanced affinity towards pNPX. After 5 cycles, the relative activities of the co-immobilized enzymes towards pNPX and corncob xylan were 52% and 70% respectively, and the accumulated amount of reducing sugars obtained by co-immobilized enzymes degrading corncob xylan in 30% (v/v) acetone solution was 1.7 times than that with no acetone.


Asunto(s)
Estructuras Metalorgánicas , Xilosidasas , Endo-1,4-beta Xilanasas , Circonio , Temperatura , Xilanos , Acetona , Enzimas Inmovilizadas , Concentración de Iones de Hidrógeno , Xilosidasas/química
14.
Pharmaceutics ; 15(7)2023 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-37514006

RESUMEN

Cancer has emerged as a leading cause of death worldwide. However, the pursuit of precise cancer therapy and high-efficiency delivery of antitumor drugs remains an enormous obstacle. The major challenge is the lack of a smart drug delivery system with the advantages of biodegradability, biocompatibility, stability, targeting and response release. Zein, a plant-based protein, possesses a unique self-assembly ability to encapsulate anticancer drugs directly or indirectly. Using zein as a nanotherapeutic pharmaceutic preparation can protect anticancer drugs from harsh environments, such as sunlight, stomach acid and pepsin. Moreover, the surface functionalization of zein is easily realized, which can endow it with targeting and stimulus-responsive release capacity. Hence, zein is an ideal nanocarrier for the precise delivery of anticancer drugs. Combined with our previous research experiences, we attempt to review the current state of the preparation of zein-based nanocarriers for anticancer drug delivery. The challenges, solutions and development trends of zein-based nanocarriers for precise cancer therapy are discussed. This review will provide a guideline for precise cancer therapy in the future.

15.
ACS Appl Mater Interfaces ; 15(6): 7767-7776, 2023 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-36732699

RESUMEN

Developments of a drug delivery system (DDS) based on a natural supramolecular hydrogel have been of wide interest due to its biocompatibility, efficacy, and adjustable performance. However, a simple and efficient design of functional hydrogel DDS based on the templated interplay of gelator and model drug is still a challenge. In this work, natural glycyrrhetinic acid (GA) gel was selected as a carrier to encapsulate the model drug pyrazinamide (PZA). It was found that the carboxyl-amide interaction at the interface of gel-drug achieved polymorph control, stabilization, and pH-responsive release. Powder X-ray diffraction confirmed that the metastable γ form of PZA was obtained from the GA gel. Spectral analysis and molecular dynamics simulation showed that the protonation at the amide-O promoted the discretization of PZA molecules in solution, resulting in the polymorphism. Furthermore, the gel-drug interplay increased the stability of the γ form significantly from 2 days to 3 months by in situ encapsulation in the GA gel. In vitro release study indicated that the GA gel achieved targeted control release of PZA due to the pH-responsiveness property of GA. This work provides a promising option for hydrogel-based DDS design combined with polymorph control and stabilization.


Asunto(s)
Ácido Glicirretínico , Hidrogeles , Hidrogeles/química , Ácido Glicirrínico , Preparaciones de Acción Retardada/farmacología , Sistemas de Liberación de Medicamentos/métodos , Ácido Glicirretínico/química
16.
Biochimie ; 209: 85-94, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36773834

RESUMEN

Diet-induced obesity in mice and humans is commonly associated with an imbalance between energy intake and expenditure. Reportedly, creatine can enhance energy expenditure in brown adipose tissue and reduce hepatic triglycerides accumulation; however, the molecular mechanism underlying the role of exogenous creatine supplementation in regulating lipid droplet mobilization remains elusive. Herein, we employed a high-fat diet (HFD)- induced mouse model to investigate the role of creatine in regulating lipolysis and lipophagy in brown adipose tissue and the liver. Exogenous creatine supplementation ameliorated HFD-induced obesity, increased insulin sensitivity and improved glucose homeostasis. Creatine supplementation enhanced the expression of uncoupling protein 1 (UCP1), cell death-inducing DNA fragmentation factor alpha-like effector A (CIDEA), and other brown adipose tissue-specific thermogenic genes Cpt1a, Gyk, and Pgc1ß in brown adipose tissue. Furthermore, creatine inhibited the expression of CIDEA, which promotes hepatic lipid accumulation. Creatine stimulated the expression of triglyceride lipase adipose triglyceride lipase, and phospho-hormone-sensitive lipase (HSL) induced increased lipolysis in brown adipose tissue and the liver. Meanwhile, reduced LC3B expression was accompanied by an increased level of p62 in HFD-fed mice, indicating diminished basal autophagy in brown adipose tissue and the liver; however, creatine enhanced P62/LC3B induced lipophagy in brown adipose tissue and the liver. Collectively, our results suggest that creatine may function as a brown adipose tissue activator to increase whole-body energy metabolism via coordinated lipolysis and lipophagy in brown adipose tissue and the liver.


Asunto(s)
Tejido Adiposo Pardo , Lipólisis , Humanos , Ratones , Animales , Tejido Adiposo Pardo/metabolismo , Creatina/metabolismo , Dieta Alta en Grasa/efectos adversos , Tejido Adiposo Blanco/metabolismo , Obesidad/metabolismo , Hígado/metabolismo , Metabolismo Energético/fisiología , Autofagia , Lipasa/metabolismo , Tejido Adiposo/metabolismo
17.
Materials (Basel) ; 16(12)2023 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-37374638

RESUMEN

The Portevin-Le Chatelier effect of Cu-2.0Be alloy was investigated using hot isothermal compression at varying strain rates (0.01-10 s-1) and temperature (903-1063 K). An Arrhenius-type constitutive equation was developed, and the average activation was determined. Both strain-rate-sensitive and temperature-sensitive serrations were identified. The stress-strain curve exhibited three types of serrations: type A at high strain rates, type B (mixed A + B) at medium strain rates, and type C at low strain rates. The serration mechanism is mainly affected by the interaction between the velocity of solute atom diffusion and movable dislocations. As the strain rate increases, the dislocations outpace the diffusion speed of the solute atoms, limiting their ability to effectively pin the dislocations, resulting in lower dislocation density and serration amplitude. Moreover, the dynamic phase transformation triggers the formation of nanoscale dispersive ß phases, which impede dislocation and cause a rapid increase in the effective stress required for unpinning, leading to the formation of mixed A + B serrations at 1 s-1.

18.
Materials (Basel) ; 15(8)2022 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-35454488

RESUMEN

In order to prepare edible films with outstanding antimicrobials and antioxidants utilized in applications of food and pharmaceutics, in this study, effects of surfactants on zein cast films for simultaneous delivery of lysozyme (LY) and ascorbic acid (AA) were investigated, where sodium alginate (SA), soy lecithin (SL), and Pluronic f-68 (PF-68) were selected as surfactants. FT-IR tests indicated that SL or PF-68 dramatically changed secondary structure of zein composite films, which heightened the irregularity of the composite film and inhibited LY crystallization. Mechanical tests showed that highly flexible films exhibiting elongations between 129% and 157% were obtained when adding PF-68. Compared with the film without emulsifier, zein film containing SL and PF-68 showed approximately 7.51 and 0.55 times lower initial release rates for LY and AA respectively, which significantly improved the controlled release and heightened the anti-microbial and anti-oxidant activities of the film. Finally, emulsified mechanisms of the surfactants in zein films were proposed.

19.
ACS Omega ; 7(35): 31338-31347, 2022 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-36092597

RESUMEN

Protein solubility is very important for protein crystallization, bioprocess development, and protein application. In this study, a method based on the stability of a protein dispersion system is proposed for fast assessment of protein solubility, which mainly involves ultrasonic dispersion, differential centrifugation, and spectral measurement (UDDCS) and curvature estimation. The appropriate ultrasonic time and centrifugal time were experimentally determined at first. The results show that the relationship between the standard deviation and the protein concentrations originally added accords with the modified exponential equation, and the corresponding concentration of the maximum curvature point is defined as the solubility of the protein. Lysozyme solubility data in NaCl aqueous solutions and zein solubility data in ethanol aqueous solutions are selected to verify the UDDCS method by comparing the data obtained by the UDDCS method and the results from references, and the results indicate that the UDDCS method is reliable, universal, and time-saving. Finally, measurements of zein solubility in NaOH solution and casein solubility in urea aqueous solution were conducted as test cases by the UDDCS method.

20.
Front Psychol ; 13: 912242, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36132192

RESUMEN

Criminals targeting and exploiting older adults in online environments are of great concern. This study systematically retrieved and analyzed articles on the psychological characteristics of older adult victims of online fraud. First, we found that there was no evidence that older adults were more prevalent than other individuals of other ages among online fraud victims, and current researchers have focused more on why older adults are easy targets for fraud (susceptibility to being cheated). Second, research on psychological factors of older adults' susceptibility to online fraud has mainly focused on cognitive function, trust traits, and other personality traits, such as social loneliness, the Big Five personality traits, and self-control. Among them, most researchers claim that the cyber-cheating of older adults may be due to a decline in their cognitive function. However, there has not been a consensus on how cognitive function and physical and mental conditions affect older people who are cheated. Third, techniques (i.e., methods and techniques used by fraudsters) and experience (i.e., familiarity with internet technology or fraud) may be related to the susceptibility of older adults to fraud, and these studies have also not yet generated a consensus supported by reliable data. Based on the above research uncertainties, we propose that fraud prevention and control strategies for older adults should be applied with caution.

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