Search

Extracting eigenvalues from vibration pulse signals is a crucial aspect of diagnosing faults in wind turbine gearbox bearings. However, the presence of ambient noise and high-frequency harmonics in the vibration signals brings a challenge in identifying fault information. This study proposes a malfunction diagnostic research approach based on the ICEEMDAN–flexible wavelet threshold to accurately and thoroughly identify malfunction feature messages from vibration signals. The approach decomposes the vibration signal into multiple intrinsic mode function (IMF) constituents using intrinsic computing expressive empirical mode decomposition with adaptive noise (ICEEMDAN). The correlation coefficient method is then utilized to identify noise-focused and message-focused IMF constituents, with the message-focused IMF constituents being retained and the noise-focused IMF constituents undergoing ICEEMDAN decomposition again. The scale function for each component is gained by detrended fluctuation analysis (DFA). Subsequently, a flexible wavelet threshold is applied to the noise-focused IMF constituent produced by the second stage of decomposition to extract meaningful signal messages. Ultimately, the message-focused IMF constituent produced by both stages of decomposition and the obtained signal of wavelet noise reduction yields a reconstructed signal. The experimental and simulation results show that the SNR of the flexible wavelet threshold is 37.09, which is 3.9 and 7.6% higher than the hard and soft thresholds, respectively. Meanwhile, the MSE of flexible wavelet thresholding is 0.0019, which is reduced by 26.9 and 44.1% compared with hard and soft thresholding, respectively. Therefore, the proposed method in the paper can effectively retrieve signal messages, and the comparison with the traditional method indicates the advantage of the approach proposed in the research for wind turbine gearbox bearing malfunction diagnostic. [ABSTRACT FROM AUTHOR]

Copyright of Acta Mechanica Sinica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Delivery of hydrophilic small molecule therapeutics by traditional drug delivery systems is challenging. Herein, we have used the specific interaction between DNA aptamers and drugs to create simple and effective drug depot systems. The specific binding of a phosphorothioate-modified aptamer to drugs formed non-covalent aptamer/drug complexes, which created a sustained release system. We demonstrated the effectiveness of this system with small hydrophilic molecules, the site 1 sodium channel blockers tetrodotoxin and saxitoxin. The aptamer-based delivery system greatly prolonged the duration of local anesthesia and reduced systemic toxicity. The beneficial effects of the aptamers were restricted to the compounds they were specific to. These studies establish aptamers as a class of highly specific, modifiable drug delivery systems, and demonstrate potential usefulness in the management of postoperative pain. Controlled delivery of small molecule therapeutics is challenging. Here the authors report a simple and effective aptamer-based depot system where the formation of aptamer/drug complexes leads to sustained release, and using this approach demonstrate improved in vivo delivery of channel blockers. [ABSTRACT FROM AUTHOR]

The effects of konjac glucomannan (KGM) and acetylated distarch phosphate (ADSP) on properties of pork meat myofibrillar protein (MP) were investigated using rotary rheometer, colorimeter, texture analyzer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM). The addition of KGM and ADSP resulted in increase in both storage modulus (G′) and water holding capacity. Whiteness of MP gels was not influenced by the addition of KGM or ADSP, but the texture of MP gels changed apparently with the incorporation of KGM or ADSP. The temperature sweep showed that the increase in G′ was associated with the gelatinization of ADSP and its synergistic effect with KGM. The FTIR indicated that the addition of KGM and ADSP enhanced the hydrogen bond in the gel system. The addition of KGM and ADSP changed the microstructures of MP gels, indicating the possible interactions among KGM, ADSP and MP. The images of CLSM showed that starch granules filled in the gap in the protein network, meanwhile the KGM evenly dispersed in the protein network structure. [ABSTRACT FROM AUTHOR]

The effect of excipient emulsions with different lipid droplet sizes on carotenoid bioaccessibility from tomatoes was investigated using a simulated gastrointestinal tract (GIT). Excipient emulsions with different surface-weighted mean droplet diameters were fabricated: d = 0.15 μm (small), 0.40 μm (medium), and 22.3 μm (large). Changes in particle size, microstructure, ζ-potential, and carotenoid bioaccessibility were measured when tomato-emulsion mixtures that had received different thermal and mixing treatments were passed through the GIT model. Carotenoid bioaccessibility decreased with increasing initial droplet size (small ≥ medium > large), which was attributed to two effects. First, smaller droplets extracted carotenoids from tomato tissue more efficiently. Second, smaller droplets were digested faster leading to more rapid mixed micelle formation, thereby increasing carotenoid solubilization in intestinal fluids. Carotenoid bioaccessibility was higher from boiled than raw tomatoes because thermal disruption of the plant tissue facilitated carotenoid release. Carotenoid bioaccessibility was higher when tomatoes were boiled with emulsions than when they were boiled alone and then added to emulsions. In conclusion, excipient emulsions are highly effective at increasing carotenoid bioaccessibility from tomatoes, but lipid droplet size must be optimized to ensure high efficacy. [ABSTRACT FROM AUTHOR]

The influence of oil type on the ability of excipient emulsions to improve the solubility, stability, and bioaccessibility of curcumin was examined. Oil-in-water emulsions were prepared using coconut, sunflower, corn, flaxseed, or fish oils. These excipient emulsions were then mixed with powdered curcumin and incubated at 30 or 100 °C. For all oils, more curcumin was transferred from powder to excipient emulsion at 100 °C (190-200 μg/mL) than at 30 °C (30-36 μg/mL), which was attributed to increased curcumin solubility with temperature. Oil type influenced the stability and bioaccessibility of curcumin when excipient emulsions were exposed to simulated gastrointestinal tract conditions, which was attributed to differences in the molecular composition and physicochemical properties of the oils. Overall, the use of fish oil led to the highest effective curcumin bioavailability (38 %). This study provides valuable information for optimizing excipient emulsions to increase curcumin bioavailability in food, supplement, or pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Powdered curcumin was either dissolved in the lipid phase of a nanoemulsion delivery system or it was directly mixed with an excipient nanoemulsion. The influence of thermal treatment (30 or 90 °C) and protein addition (caseinate) on the bioaccessibility and transformation of curcumin was then investigated using a simulated gastrointestinal tract (GIT) model: mouth; stomach; small intestine. Curcumin solubility was high in nanoemulsion delivery systems exposed to both thermal treatments because it was already present in the lipid phase. Conversely, curcumin solubility of a powder mixed with an excipient nanoemulsion was appreciably lower when exposed to 30 °C than 90 °C. This effect was attributed to the greater transfer of curcumin to the lipid phase of the excipient nanoemulsions at elevated temperatures. For the heated samples, the bioaccessibility and transformation of curcumin was not greatly affected by original curcumin location or protein addition. However, curcumin bioaccessibility was appreciably higher in the presence of nanoemulsion lipid droplets than in their absence, which was attributed to an increase in the solubilization capacity of the mixed micelle phase. This study provides some useful information for improving the design of functional foods to improve the oral bioavailability profile of lipophilic nutraceuticals. [ABSTRACT FROM AUTHOR]

Nanoemulsion-based delivery systems are finding increasing use in food, pharmaceutical, agrochemical, and personal care applications due to their ability to increase the stability and/or activity of lipophilic functional components. In this study, a low-energy homogenization method (spontaneous emulsification) was used to encapsulate β-carotene in nanoemulsions. The main objective was to optimize lipid phase composition to form stable nanoemulsions that would effectively enhance β-carotene bioavailability. Lipid phase composition was varied by mixing long chain triglycerides (LCT) with medium chain triglycerides (MCT) or flavor oil (orange oil). LCT was added to promote bioaccessibility, whereas MCT or orange oil was added to facilitate nanoemulsion formation. Our hypothesis was that an optimum level of LCT is required to form stable nanoemulsions with good bioaccessibility characteristics. Stable nanoemulsions could be formed at LCT-to-orange oil ratios of 1:1 ( d = 109 nm) and at LCT-to-MCT ratios of 1:2 ( d = 145 nm). Thus, higher LCT loading capacities and smaller droplet sizes could be obtained using orange oil. The influence of oil composition on the potential gastrointestinal fate of the nanoemulsions was studied using a simulated gastrointestinal tract (GIT) consisting of mouth, stomach, and small intestine phases. The transformation and bioaccessibility of β-carotene in the GIT was highly dependent on lipid phase composition. In particular, β-carotene bioaccessibility increased with increasing LCT level due to greater solubilization in mixed micelles. These results are useful for optimizing the design of nanoemulsion-based delivery systems for encapsulation and release of lipophilic nutraceuticals and pharmaceuticals. [ABSTRACT FROM AUTHOR]

The influence of lipid concentration on the ability of excipient emulsions to increase carotenoid bioaccessibility from raw and cooked carrots was investigated using a simulated gastrointestinal tract (GIT). Excipient emulsions were fabricated using whey protein as a natural emulsifier and a long chain triglyceride (corn oil) as a digestible lipid. Changes in particle size, charge, and microstructure were determined as the carrot-emulsion mixtures were passed through simulated mouth, stomach, and small intestine. Carotenoid bioaccessibility increased with increasing digestible lipid concentration in the excipient emulsions (from 0 to 8 %). Carotenoid bioaccessibility was higher from boiled carrots than for raw carrots, which was attributed to disruption of plant cell structure facilitating carotenoid release. In conclusion, excipient emulsions are highly effective at increasing carotenoid bioaccessibility from carrots, which can be attributed to the ability of the small lipid droplets to rapidly solubilize the carotenoids. [ABSTRACT FROM AUTHOR]

The original version of this article unfortunately contained a mistake. The spelling of David Julian McClements name was incorrect. [ABSTRACT FROM AUTHOR]