Optimizing the design of nanostructures for improved thermal conduction within confined spaces

Maintaining constant temperature is of particular importance to the normal operation of electronic devices. Aiming at the question, this paper proposes an optimum design of nanostructures made of high thermal conductive nanomaterials to provide outstanding heat dissipation from the confined interior (possibly nanosized) to the micro-spaces of electronic devices. The design incorporates a carbon nanocone for conducting heat from the interior to the exterior of a miniature electronic device, with the optimum diameter, D0, of the nanocone satisfying the relationship: D02(x) ∝ x1/2 where x is the position along the length direction of the carbon nanocone. Branched structure made of single-walled carbon nanotubes (CNTs) are shown to be particularly suitable for the purpose. It was found that the total thermal resistance of a branched structure reaches a minimum when the diameter ratio, β* satisfies the relationship: β* = γ-0.25bN-1/k*, where γ is ratio of length, b = 0.3 to approximately 0.4 on the single-walled CNTs, b = 0.6 to approximately 0.8 on the multiwalled CNTs, k* = 2 and N is the bifurcation number (N = 2, 3, 4 ...). The findings of this research provide a blueprint in designing miniaturized electronic devices with outstanding heat dissipation

Impact of thermal processing on dietary flavonoids

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGFlavonoids are widely distributed in natural products and foods as a class of polyphenols. They processed diverse bioactivities, including anti-inflammation activity, antiaging activity, and antioxidant activity. The foods rich in flavonoids are usually consumed after thermal processing. However, flavonoids are commonly vulnerable under thermal processing, and it could cause various influences on their stability and bioactivities. Therefore, in this review, the effects of thermal processing on thermal stability and bioactivities of dietary flavonoids from different food sources were first summarized. The strategies to improve thermal stability of dietary flavonoids were then discussed. Noticeably, the effect of some of the promising thermal technologies on dietary flavonoids was also clarified preliminarily in the current review. The promising thermal technologies may be an alternative to conventional thermal processing technologies.Agencia Estatal de Investigación | Ref. RYC2020-030365-

Antifungal Activity and Mechanism of Perillaldehyde against Penicillium citrinum, a Major Fungal Pathogen of Myrica rubra

Perillaldehyde is a green and safe natural antibacterial substance extracted from perilla leaves, which is also used as a food additive in food production. In this study, the inhibitory effect of perillaldehyde on Penicillium citrinum, a major pathogen of Chinese bayberry (Myrica rubra), was investigated by minimum inhibitory concentration (MIC), spore germination rate and mycelial growth inhibition assays, and the underlying mechanism was elucidated by studying the mycelial morphology and ultrastructure, cell membrane damage, membrane lipid peroxidation and changes in functional groups. The results showed that the MIC of perillaldehyde on P. citrinum was 120 μL/L. Mycelial growth was completely inhibited by treatment with 120 μL/L perillaldehyde, and the relative conductivity and malondialdehyde (MDA) content increased. Compared with the untreated group, ergosterol, total lipid and chitin contents and mitochondrial adenosine triphosphatase (ATPase) activity decreased by 80.00%, 81.25%, 64.97% and 87.40% in P. citrinum treated with 90 μL/L perillaldehyde. The treatment with perillaldehyde damaged cell membrane permeability and affected the normal physiological function of the cell membrane. By scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was found showed that the broom-like conidial head of P. citrinum disappeared after perillaldehyde treatment, and the mycelia appeared to be broken and ablated. Moreover, the cell membrane was broken, intracellular contents leaked out, and the cells became shriveled. In addition, the amounts of leakage of soluble protein, soluble sugar and nucleic acid from P. citrinum treated with 120 μL/L perillaldehyde for 5 h increased by 71.20%, 210.93% and 117.31% compared with those before the treatment, which verified cell membrane damage. By using Fourier transform infrared (FTIR) spectroscopy, it was found that the contents of functional groups such as hydroxyl, methyl, aromatic carbon skeleton and benzene ring carbon skeleton in perillaldehyde treated P. citrinum decreased, and internal substances were gradually consumed. In summary, perillaldehyde showed a good antifungal activity on P. citrinum by destroying cell membrane structure, changing membrane permeability, interfering with energy metabolism and destroying protein and genetic material. Perillaldehyde has good research and development prospects as a natural preservative

Effects on Physicochemical and Dissolution Characteristics of Lentinus edodes Stem Powder by Jet Milling

In order to increase the utilization rate of shiitake mushroom by-products, the shiitake mushroom stem was crushed after superfine grinding with a jet mill, with coarse powder and 40 mesh powder as the control. The effect of jet milling on the physicochemical properties of shiitake mushroom stem powder and the dissolution amount of functional components represented by ergosterol and polysaccharides were studied. The cumulative dissolution rate of ergosterol and polysaccharides was fitted by the Weibull model. The results showed that after superfine grinding by jet milling, the average particle size (D50) of powder decreased to 3.21 μm, bulk density, tap density and L* value increased from 0.15 g/mL to 0.25 g/mL, 0.23 g/mL to 0.42 g/mL, 65.31 to 73.49, respectively. The superfine powder fluidity, water holding capacity and swelling capacity were significantly enhanced (P<0.05). The cumulative dissolution 50% of the time (T50) of ergosterol and polysaccharide in superfine powder was reduced by 2.56 min and 8.14 min, respectively, compared with coarse powder. And cumulative dissolution rate at 45 min (Q45) increased by 10.88% and 19.15%, respectively. The powder properties and the dissolution rate of the functional ingredients were improved, after the jet milling to treat the shiitake mushroom stem, which was conducive to the comprehensive utilization of shiitake mushroom by-products

Optimization of Preparation Process of Bayberry Soft Candy and Analysis of Its Hypoglycemic Function

In order to develop soft fruit candy products with hypoglycemic function, the preparation method was optimized by single-factor and response surface studies. The texture profile analysis and sensory score was regarded as the evaluation indices, while bayberry juice was used as the main raw material, carrageenan and gelatin as the gelling agent, and xylitol as the sweetener. Additionally, the hypoglycemic effect of bayberry soft candy extract was evaluated by in vitro study, and the components of bayberry juice was detected by using UPLC-MS/MS assay. Finally, the hypoglycemic components and related pathways of action were predicted by network pharmacology. The results showed that in the 100 mL bayberry soft candy gel solution system, the optimal formulation of bayberry soft candy obtained by response surface methodology was as follows: 89.37% bayberry juice for swelling and constant volume, with 9.90% gelatin, 1.41% carrageenan, and 30.86% xylitol addition. The sensory score of bayberry soft candy produced under this process was 87.30, which was close to the theoretical value. The in vitro hypoglycemic study showed that the inhibition of α-glucosidase and α-amylase by 4 mg/mL of bayberry soft candy extract reached 98.58% and 86.89%, respectively. The network pharmacological analysis postulated that 3,5-diacetyltambrin (YM16), azaleatin (YM17) and raspberry ketone glucoside (YM1) were the key hypoglycemic components in bayberry juice, in addition, the human cancer pathway and PI3K-Akt pathway were important pathways of their action. The soft candy prepared under the optimal process condition showed good elasticity, fantastic taste and certain hypoglycemic effects. These results provide a certain theoretical basis for the development of fruit-flavored functional soft candy

Effects of different protease treatment on protein degradation and flavor components of Lentinus edodes

Abstract Shiitake mushrooms (Lentinus edodes) form a great source of protein; however, the effect of enzymatic hydrolysis to improve its flavor has not yet been investigated. To explore the effects of different protease treatments on protein degradation and flavor compounds of shiitake mushrooms, papain, neutral protease, and flavourzyme were selected for the hydrolysis of shiitake mushrooms. Proteolysis index, Trichloroacetic acid‐nitrogen soluble index, and protein content were estimated to evaluate protein degradation. Flavor amino acids and volatile components of the hydrolysate were also analyzed. Results showed flavourzyme has an advantage over the others in promoting protein degradation and improving flavor. Compared to single‐enzyme treatment, a combination treatment with three enzymes, at 1:1:1 ratio, was found to perform greater protein hydrolysis. After protease‐mediated hydrolysis, the variety and content of flavor substances (free amino acids and eight‐carbon compounds) in L. edodes increased. We concluded that protease treatment is an effective method for improving the quality and flavor of L. edodes

Evaluation of the effectiveness of amendments derived from vermicompost combined with modified shell powder on Cd immobilization in Cd-contaminated soil by multiscale experiments

The widespread heavy metal contamination of agricultural soils poses an enormous challenge to food safety. To evaluate the Cd immobilization potential of vermicompost combined with modified shell powder (VMSP) on Cd-contaminated soil, batch adsorption tests and field experiments were conducted. First, the Cd2+ removal characteristics and adsorption mechanisms of vermicompost (V), vermicompost combined with shell powder (VSP), and VMSP in an aqueous solution were investigated by batch tests. Then, 3 kg·m2 V, VSP, and VMSP doses were applied to Cd-contaminated farmland soils as soil amendments to plant green garlic (Allium sativum L.) and investigate their Cd immobilization effects in Cd-contaminated soils. Batch adsorption tests showed that VMSP was most effective for Cd2+ removal, with adsorption rates as high as 85.7–99.79% and desorption rates of approximately 1.25–1.34%. Combining further characterization analysis of VMSP, it was demonstrated that the adsorption mechanism of Cd2+ was monolayer chemisorption, mainly involving the complexation reaction of Cd2+ with organic functional groups and the precipitation reaction of Cd2+ with mineral elements. The field experiment showed that adding V, VSP, and VMSP effectively inhibited the enrichment of Cd in green garlic, and the Cd content was reduced by 42.18%, 46.88%, and 68.75%, respectively. However, only the Cd content of green garlic treated with VMSP was lower than the national standard for food safety in China (Cd≤ 0.2 mg·kg-1). V, VSP, and VMSP additions improved soil fertility and reduced Cd bioavailability in the soil by 15.5%, 18.9%, and 36.3%, respectively. In addition, V, VSP, and VMSP addition increased bacterial diversity and improved bacterial communities and functions in the soil by improving basic soil properties and reducing Cd-related toxicity. The results indicated that VMSP is a promising amendment for Cd immobilization in Cd-contaminated farmland soils