RESUMEN
Hydrogels, recognized for their flexibility and diverse characteristics, are extensively used in medical fields such as wearable sensors and soft robotics. However, many hydrogel sensors derived from biomaterials lack mechanical strength and fatigue resistance, emphasizing the necessity for enhanced formulations. In this work, we utilized acrylamide and polyacrylamide as the primary polymer network, incorporated chemically modified poly(ethylene glycol) (DF-PEG) as a physical crosslinker, and introduced varying amounts of methacrylated lysine (LysMA) to prepare a series of hydrogels. This formulation was labeled as poly(acrylamide)-DF-PEG-LysMA, abbreviated as pADLx, with x denoting the weight/volume percentage of LysMA. We observed that when the hydrogel contained 2.5% w/v LysMA (pADL2.5), compared to hydrogels without LysMA (pADL0), its stress increased by 642 ± 76%, strain increased by 1790 ± 95%, and toughness increased by 2037 ± 320%. Our speculation regarding the enhanced mechanical performance of the pADL2.5 hydrogel revolves around the synergistic effects arising from the co-polymerization of LysMA with acrylamide and the formation of multiple intermolecular hydrogen bonds within the network structures. Moreover, the acid, amine, and amide groups present in the LysMA molecules have proven to be instrumental contributors to the self-adhesion capability of the hydrogel. The validation of the pADL2.5 hydrogel's exceptional mechanical properties through rigorous tensile tests further underscores its suitability for use in strain sensors. The outstanding stretchability, adhesive strength, and fatigue resistance demonstrated by this hydrogel affirm its potential as a key component in the development of robust and reliable strain sensors that fulfill practical requirements.
RESUMEN
Hydrogels' exceptional mechanical strength and skin-adhesion characteristics offer significant advantages for various applications, particularly in the fields of tissue adhesion and wearable sensors. Herein, we incorporated a combination of metal-coordination and hydrogen-bonding forces in the design of stretchable and adhesive hydrogels. We synthesized four hydrogels, namely PAID-0, PAID-1, PAID-2, and PAID-3, consisting of acrylamide (AAM), N,N'-methylene-bis-acrylamide (MBA), and methacrylic-modified dopamine (DA). The impact of different ratios of iron (III) ions to DA on each hydrogel's performance was investigated. Our results demonstrate that the incorporation of iron-dopamine complexes significantly enhances the mechanical strength of the hydrogel. Interestingly, as the DA content increased, we observed a continuous and substantial improvement in both the stretchability and skin adhesiveness of the hydrogel. Among the hydrogels tested, PAID-3, which exhibited optimal mechanical properties, was selected for adhesion testing on various materials. Impressively, PAID-3 demonstrated excellent adhesion to diverse materials and, combined with the low cytotoxicity of PAID hydrogel, holds great promise as an innovative option for biomedical engineering applications.
RESUMEN
Hydrogels are conductive and stretchable, allowing for their use in flexible electronic devices, such as electronic skins, sensors, human motion monitoring, brain-computer interface, and so on. Herein, we synthesized the copolymers having various molar ratios of 3,4-ethylenedioxythiophene (EDOT) to thiophene (Th), which served as conductive additives. With doping engineering and incorporation with P(EDOT-co-Th) copolymers, hydrogels have presented excellent physical/chemical/electrical properties. It was found that the mechanical strength, adhesion ability, and conductivity of hydrogels were highly dependent on the molar ratio of EDOT to Th of the copolymers. The more the EDOT, the stronger the tensile strength and the greater the conductivity, but the lower the elongation break tends to be. By comprehensively evaluating the physical/chemical/electrical properties and cost of material use, the hydrogel incorporated with a 7:3 molar ratio P(EDOT-co-Th) copolymer was an optimal formulation for soft electronic devices.
RESUMEN
Rayleigh-Taylor instability (RTI) under radiation background is commonly found in both engineering applications and natural phenomena. In the optically thin and incompressible limit, the corresponding problem can be simplified as an interface discontinuous acceleration (IDA) RTI problem, but to date has only been studied in the linear stage. In this paper, the entire IDA-RTI evolution was studied numerically and theoretically, particularly for the stages beyond the linear stage. The results show that the IDA-RTI problem is equivalent to the classical RTI with the effective acceleration g_{eff}^{*} that is introduced in this work. Moreover, our studies further show that IDA-RTI can occur if and only if g_{eff}^{*}>0 (from heavy fluid to light fluid). This criterion means that IDA-RTI can occur when (i) heavy fluid supports (or accelerates) the light fluid or (ii) the two fluids have the same density, in contrast to the classical RTI problem. Moreover, the quasisteady bubble and spike velocities are theoretically predicted with quantitative accuracy, showing good agreement with the results of numerical simulations in a wide range of density ratios and acceleration configurations.
RESUMEN
This work aimed to develop a novel colorimetric indicator film for monitoring of food freshness based on gelatin/polyvinyl alcohol matrix incorporated with anthocyanin extracts from mulberry. The color of anthocyanin extracts solutions obviously changed from bright red to dark green in the pH range of 2.0-11.0. FTIR spectra and isothermal titration calorimetry showed that the anthocyanin extracts were successfully combined with gelatin/polyvinyl alcohol matrix by hydrogen binding and electrostatic interaction, which enhanced the stability of anthocyanin. The scanning electric microscopy showed that the compatibility between polyvinyl alcohol and gelatin were improved owing to the addition of anthocyanin extracts. With the anthocyanin extracts addition from 0 to 45â¯mg/100â¯mL mixed solution, the tensile strength decreased from 30.80 to 21.01â¯MPa and the elongation at break increased from 589.22% to 905.86%. The color response of film in buffer solution of different pH were in accordance with anthocyanin extracts solutions, and its color changes were clearly visible with naked eye. Finally, the film was evaluated by a test on monitoring fish spoilage, which presented visible color changes due to volatile nitrogenous compounds formed over time. These results showed that this developed film could be used as an effective method for the monitoring of food freshness.
Asunto(s)
Antocianinas/química , Embalaje de Alimentos/instrumentación , Indicadores y Reactivos/química , Morus/química , Alcohol Polivinílico/química , Alimentos Marinos , Animales , Colorimetría , Peces , Almacenamiento de Alimentos/instrumentación , Gelatina/química , Enlace de Hidrógeno , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Extractos Vegetales/química , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad EstáticaRESUMEN
AIM: To study whether infertile patients with endometriosis have a higher prevalence of endometrial polyps, and to clarify the characteristics of the pathology of combined polyps. METHODS: Infertile patients who had undergone both hysteroscopy and laparoscopy in Reproductive Hospital Affiliated with Shandong University from January 2014 to May 2017 were enrolled. Patients with and without endometriosis, diagnosed by laparoscopy, were staged and included in the study group and control group, respectively, and the prevalence of polyps was compared. The pathological types of endometrial polyps were analyzed. RESULTS: A total of 414 cases were enrolled in the study group and 3,048 cases in the control group; polyps were diagnosed, with endoscopy, in 1,107 patients. Endometrial polyps were detected by hysteroscopy in 47.83% of the endometriosis group and 29.82% of the control group. The prevalence of endometrial polyps was significantly higher in the endometriosis group than in the control group (p < 0.001) but not significantly different between stages of endometriosis (p = 0.580). The pathological diagnosis included 899 endometrial polyps and 208 polypoid hyperplasia; 66.5% of endometrial polyps were combined with simple hyperplasia. CONCLUSIONS: The infertile patients with endometriosis had a higher prevalence of endometrial polyps, and those polyps are often combined with simple hyperplasia.
Asunto(s)
Neoplasias Endometriales/epidemiología , Endometriosis/complicaciones , Infertilidad Femenina/complicaciones , Pólipos/epidemiología , Adulto , Estudios de Cohortes , Neoplasias Endometriales/complicaciones , Neoplasias Endometriales/patología , Femenino , Humanos , Histeroscopía/estadística & datos numéricos , Infertilidad Femenina/diagnóstico , Laparoscopía/estadística & datos numéricos , Persona de Mediana Edad , Pólipos/complicaciones , Pólipos/patología , Embarazo , Prevalencia , Estudios RetrospectivosRESUMEN
Implicit large eddy simulations of two-dimensional Rayleigh-Taylor instability at different density ratios (i.e., Atwood number A=0.05, 0.5, and 0.9) are conducted to investigate the late-time dynamics of bubbles. To produce a flow field full of bounded, semibounded, and chaotic bubbles, three problems with distinct perturbations are simulated: (I) periodic sinusoidal perturbation, (II) isolated W-shaped perturbation, and (III) random short-wave perturbations. The evolution of height h, velocity v, and diameter D of the (dominant) bubble with time t are formulated and analyzed. In problem I, during the quasisteady stage, the simulations confirm Goncharov's prediction of the terminal speed v_{∞}=Frsqrt[Agλ/(1+A)], where Fr=1/sqrt[3π]. Moreover, the diameter D at this stage is found to be proportional to the initial perturbation wavelength λ as D≈λ. This differed from Daly's simulation result of D=λ(1+A)/2. In problem II, a W-shaped perturbation is designed to produce a bubble environment similar to that of chaotic bubbles in problem III. We obtain a similar terminal speed relationship as above, but Fr is replaced by Fr_{w}≈0.63. In problem III, the simulations show that h grows quadratically with the bubble acceleration constant α≡h/(Agt^{2})≈0.05, and D expands self-similarly with a steady aspect ratio ß≡D/h≈(1+A)/2, which differs from existing theories. Therefore, following the mechanism of self-similar growth, we derive a relationship of ß=4α(1+A)/Fr_{w}^{2} to relate the evolution of chaotic bubbles in problem III to that of semibounded bubbles in problem II. The validity of this relationship highlights the fact that the dynamics of chaotic bubbles in problem III are similar to the semibounded isolated bubbles in problem II, but not to that of bounded periodic bubbles in problem I.
RESUMEN
The experiment was conducted to assess the protective effects of Momordica grosvenori extract (MGE) against lipid and protein oxidation-induced damage in vacuum-packed dried minced pork slices stored at room temperature for 21days. Antioxidant activity of MGE was evaluated by measuring its radical scavenging activities and reducing power with progressive concentrations from 40 to 200g/L. MGE was added to the dried minced pork slices at 7, 10 or 15g/100g. Results showed that inclusion of MGE in dried minced pork slice significantly delayed the formation of hexanal, thiobarbituric acid-reactive substances and carbonyls and reduced the sulfhydryl loss in a dose-dependent manner (P<0.05), indicating that MGE exerted a protective effect against lipids and protein oxidation. Concomitantly, an intense increase of redness and loss of lightness and yellowness was found to take place (P<0.05), though it exhibited little negative effects on the sensory properties of slices. Mogrosides, the main bioactive components in M. grosvenori, decreased primarily during processing while they were relatively stable during storage under vacuum condition, room temperature. All these results demonstrated MGE had great potential as a natural antioxidant used in meat products.
Asunto(s)
Conservación de Alimentos/métodos , Productos de la Carne/análisis , Momordica , Extractos Vegetales/farmacología , Carne Roja/análisis , Animales , Peroxidación de Lípido/efectos de los fármacos , Proteínas Musculares/química , Oxidación-Reducción/efectos de los fármacos , PorcinosRESUMEN
Turbulent mixing induced by Rayleigh-Taylor (RT) instability occurs ubiquitously in many natural phenomena and engineering applications. As the simplest and primary descriptor of the mixing process, the evolution of mixing width of the mixing zone plays a notable role in the flows. The flows generally involve complex varying acceleration histories and widely varying density ratios, two dominant factors affecting the evolution of mixing width. However, no satisfactory theory for predicting the evolution has yet been established. Here a theory determining the evolution of mixing width in general RT flows is established to reproduce, first, all of the documented experiments conducted for diverse (i.e., constant, impulsive, oscillating, decreasing, increasing, and complex) acceleration histories and all density ratios. The theory is established in terms of the conservation principle, with special consideration given to the asymmetry of the volume-averaged density fields occurring in actual flows. The results reveal the sensitivity or insensitivity of the evolution of a mixing front of a neighboring light or heavy fluid to the degree of asymmetry and thus explain the distinct evolutions in two experiments with the same configurations.
RESUMEN
This study was designed to evaluate mulberry anthocyanins bioconversion traits for intestinal probiotics. Five intestinal beneficial bacteria were incubated with mulberry anthocyanins under anaerobic conditions at 37°C, and bacterial ß-glucosidase activity and anthocyanin level were determined. Results demonstrated that all strains could convert mulberry anthocyanins to some extent. With high ß-glucosidase production capacity, Streptococcus thermophiles GIM 1.321 and Lactobacillus plantarum GIM 1.35 degraded mulberry anthocyanins by 46.17% and 43.62%, respectively. Mulberry anthocyanins were mainly biotransformed to chlorogenic acid, crypto-chlorogenic acid, caffeic acid, and ferulic acid during the anaerobic process. Non-enzymatic deglycosylation of anthocyanins also occurred and approximately 19.42% of the anthocyanins were degraded within 48h by this method.
Asunto(s)
Antocianinas/farmacocinética , Microbioma Gastrointestinal , Morus/química , Extractos Vegetales/farmacocinética , Probióticos , Antocianinas/análisis , Disponibilidad Biológica , Biotransformación , Ácido Clorogénico/metabolismo , Frutas/química , Mucosa Intestinal/metabolismo , Intestinos/efectos de los fármacos , Intestinos/microbiología , Lactobacillus plantarum/metabolismo , Extractos Vegetales/análisis , Streptococcus thermophilus/metabolismo , beta-Glucosidasa/metabolismoRESUMEN
A novel mesophilic anaerobic digestion process with detoxification-treated coconut shell pyroligneous was established, exhibiting an effective advantage in biogas production. The pyroligneous collected contained 166.2 g l(-1) acetic acid, indicating great potential for biogas production. Detoxification was an effective way of simultaneously enriching biodegradable ingredients and removing inhibitors (mainly as phenols and organic acids) for digestion process. The digestion process lasted 96 h and fermentation characteristics (chemical oxygen demand (COD) removal ratio, volatile fatty acid (VFA) consumptions, pH, total gas, methane yield, and phenol removal efficiency) were measured. The experiments successfully explored the optimum detoxification parameters, oxidized with 10 % H2O2 followed by overliming, and demonstrated 89.3 % COD removal, 91.4 % methane content, 0.305 LCH4/g COD removed CH4 yield, and 88.81 % phenol removal ratio. This study provided clues to overcome the negative effects of inhibitors in pyroligneous on biogas production. The findings could contribute to significant process in detoxified pretreatment of pyroligneous and develop an economically feasible technology for treating pyroligneous after producing charcoal.
Asunto(s)
Biocombustibles , Cocos/química , Fermentación , Terpenos/química , Anaerobiosis , Análisis de la Demanda Biológica de Oxígeno , Cocos/metabolismo , Ácidos Grasos Volátiles/química , Ácidos Grasos Volátiles/metabolismo , Peróxido de Hidrógeno/química , Fase I de la Desintoxicación Metabólica , Metano/biosíntesis , Metano/química , Fenoles , Terpenos/metabolismoRESUMEN
A series of Mach-number- (M) invariant scalings is derived for compressible turbulent boundary layers (CTBLs), leading to a viscosity weighted transformation for the mean-velocity profile that is superior to van Driest transformation. The theory is validated by direct numerical simulation of spatially developing CTBLs with M up to 6. A boundary layer edge is introduced to compare different M flows and is shown to better present the M-invariant multilayer structure of CTBLs. The new scalings derived from the kinetic energy balance substantiate Morkovin's hypothesis and promise accurate prediction of the mean profiles of CTBLs.
RESUMEN
AIM: To assess the antioxidative properties and the mechanism of action of dihydromyricetin (DMY) from Ampelopsis grossedentata. METHODS: The antioxidative properties of DMY were measured by scavenging 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and inhibiting lipid peroxidation induced by FeSO4-edetic acid in linoleic acid. The mechanism of antioxidative properties of DMY was tested by measuring the chelating activities of DMY for Fe2+ with ultraviolet spectrum (UV) method. RESULTS: The specific absorption of DPPH radical solution at 517 nm was reduced 73.3%-91.5% when DMY was added into the reaction solution in the concentration range from 0.01% to 0.04%. DMY was shown to greatly inhibit the increase of lipid peroxidation (LPO) values in linolei acid system catalyzed by FeSO4-edetic acid. The reaction rates (A532.min-1) of lipid peroxidation were 0.0021-0.0004 in the concentration range from 0.01% to 0.04% and the inhibition activities of DMY was found to be in a concentration-dependent manner. The mechanism of antioxidative properties of DMY was chelating Fe2+ in the Fe(2+)-dependent lipid peroxidation system. CONCLUSION: DMY showed great antioxidative effect and would be a good natural antioxidant.