Search

In this study, the wild type 6421 and the fruit color mutant E55 of pepper were evaluated for fruit color, pigment contents and quality components at different developmental stages. The results demonstrated that the fruit color of 6421 and E55 changed from green to yellow and then to red, and from green to brown and then to orange, respectively, as the fruit developed from mature green to ripe. For both 6421 and E55, the color parameters a* and C* increased, while hue angle (h) value decreased. Furthermore, chlorophyll (Chl) content declined, whereas carotenoid (Car) content increased. Additionally, the contents of VC, soluble sugar, soluble protein and capsaicin increased, while cellulose content decreased. At the mature green stage, there was no significant difference between 6421 and E55 in five color parameters (L*, a*, b*, C*, and h values), Chl and Car contents or six quality indicators (cellulose, VC, soluble sugar, soluble protein, and capsaicin contents) (P > 0.05). During the color-turning to ripening stages, L*, b* and C* values and VC and soluble sugar contents were significantly higher and soluble protein and cellulose contents were significantly lower in E55 than in 6421 (p 0.05). Correlation analysis showed that for both 6421 and E55, Chl and Car contents were significantly or extremely significantly correlated with each quality parameter except for cellulose content. Among the tested quality indicators, soluble sugar, soluble protein, and capsaicin contents were significantly or extremely significantly positively correlated with each other, while cellulose content was significantly or highly significantly negatively correlated with the other indicators. This study can serve as a theoretical basis for research on the coloration mechanism of peppers as well as for the screening and breeding of high-quality pepper cultivars.

With the development of energy storage, potassium ion batteries (PIBs) have gradually become a suitable substitute for lithium-ion batteries. Where the layered transition metal oxides cathode materials of potassium ion batteries have attracted much attention due to their high theoretical capacity, unique two-dimensional potassium ion diffusion channels, simple preparation and low cost. In this work, we designed a K0.5MnO2@MWCNT@Super P (KMP) composite electrode with P3-type layered structure as the cathode in PIBs through coprecipitation—high temperature sintering method. The SEM results show that the prepared KMP composite electrodes are secondary particles formed by three-dimensional network structures and particles through point–line contact and point–point contact. As a result, the composite electrode with a 7 : 2 : 1 weight ratio of K0.5MnO2, conductive carbon (Super-P: MWCNT = 1 : 1) and PVDF delivers a high initial discharge capacity of 112.7 mA h g–1 at a current density of 20 mA g–1 and 72.1 mA h g–1 at 100 mA g–1. And, it has a capacity retention of 44% at 100 mA g–1 after 50 cycles. The results show that the unique three-dimensional network structure not only improves the conductivity of K0.5MnO2 material, but also effectively alleviates the volume change caused by K+ in the charging and discharging process. This study provides a new way to develop layered cathode materials for high energy density potassium ion batteries. [ABSTRACT FROM AUTHOR]

The occurrence of fractures has emerged as one of the most prevalent injuries in the human body. In bone reconstruction surgery, after the implantation of porous hydroxyapatite materials, there is an initial infiltration of body fluids into the porous implant, followed by biomineralization-mediated apatite crystal formation and the subsequent ingrowth of bone cells. Despite extensive research efforts in this field, previous investigations have primarily focused on the formation of apatite crystals on exposed surfaces, with limited literature available regarding the formation of apatite crystals within the internal microstructures of bone implants. Herein, we demonstrate the occurrence of dynamic biomineralization within a three-dimensional porous hydroxyapatite/wollastonite (HA/WS) skeleton, leading to the abundant formation of nano-sized apatite crystals across diverse internal environments. Our findings reveal that these apatite nanocrystals demonstrate distinct rates of nucleation, packing densities, and crystal forms in comparison to those formed on the surface. Therefore, the objective of this study was to elucidate the temporal evolution of biomineralization processes by investigating the microstructures of nanocrystals on the internal surfaces of HA/WS three-dimensional porous materials at distinct stages of biomineralization and subsequently explore the biological activity exhibited by HA/WS when combined with cell investigation into apatite crystal biomineralization mechanisms at the nanoscale, aiming to comprehend natural bone formation processes and develop efficacious biomimetic implants for tissue engineering applications. The simultaneous examination of bone cell attachment and its interaction with ongoing internal nanocrystal formation will provide valuable insights for designing optimal scaffolds conducive to bone cell growth, which is imperative in tissue engineering endeavors. [ABSTRACT FROM AUTHOR]

Pepper (Capsicum annuum L.) is one of the most widely grown vegetable crops in China, with widespread cultivation worldwide. Fruit weight (size) is a complex trait controlled by multiple factors and is an essential determinant of pepper yield. In this study, we analyzed the transcriptome of two pepper recombinant lines with different fruit weights, 'B302' and 'B400', at five developmental stages to reveal some of the differentially expressed genes and mechanisms controlling fruit weight. The results showed that 21,878 differential genes were identified between the two specimens. Further analysis of the differentially expressed genes revealed that Boron transporter 4 was significantly highly expressed in the large-fruited pepper and almost not expressed at all in the small-fruited pepper. CaAUX1, CaAUX/IAA, CaGH3, CaSAUR, and other related genes in the Auxin signal transduction pathway were highly expressed in the large-fruited pepper but significantly reduced in the small-fruited pepper. In addition, a comparison of differentially expressed transcription factors at different times revealed that transcription factors such as CaMADS3, CaAGL8, CaATHB13, and CaATHB-40 were highly differentially expressed in the large-fruited pepper, and these transcription factors may be related to pepper fruit expansion. Through weighted gene co-expression network analysis (WGCNA), the MEorangered4 module was shown to have a highly significant correlation with fruit weight, and the key modules were analyzed by constructing the hub core gene network interactions map and core genes regulating fruit weight such as APETALA 2 were found. In conclusion, we find that the expression of relevant genes at different developmental stages was different in 'B302' and 'B400', and it was hypothesized that these genes play essential roles in the development of fruit size and that the interactions occurring between transcription factors and phytohormones may regulate the development of fruit size. [ABSTRACT FROM AUTHOR]

This paper presents a microfluidic device that can passively reduce fluctuations in an upstream fluid flow and generate a largely steady flow in a microfluidic system. The device features a series of compliant membranes that form deformable walls of a microchannel. F or an incoming pulsatile flow, passive vibrations of the membranes allow the fluid to be accumulated for an overflow and discharged for an underflow, resulting in drastically reduced fluctuations in flow rate and pressure. A lumped-parameter model is developed to simulate the device characteristics, in which the coupling of membrane vibrations and fluid flow in individual channel sections associated with a single membrane is first represented by squeeze-film theory and inertia-free structural dynamics. The entire device is next represented as a system by connecting individual channel sections in series. The model is numerically solved, and the results agree with experiments. The theoretical and experimental results both show that a five-membrane device can stabilize a pulsating flow by a factor of about 20. These results also reveal that smaller average flow rate, smaller fluctuation, and higher fluctuation frequency lead to more effective flow stabilization. With these characteristics, the flow stabilizer can be used to obtain steady flow in microfluidic systems. [2008-0305] Index Terms---Compliant membrane, flow rectification, flow stabilization, fluid-structure interaction, lumped-parameter model.

This paper presents a self-adaptive microfluidic variable resistor that accomplishes passive control of liquid flows by exploiting the large compliance of elastomeric polymers such as polydimethylsiloxane. The device features a compliant microstructure embedded in a microchannel that consists of a flexible thin flap and a stiff stopper located in close proximity. The shape and size of the gap between the flap and stopper vary with the applied pressure, resulting in small resistance with respect to forward flow and large resistance with respect to reverse flow. The variable flow resistor shows an interesting diode behavior because its flow resistance is drastically different for different directions of applied pressures and is self-adaptive in the sense that its flow resistance varies with reverse pressure in such a way that the resulting flow rate remains a constant. That is, the flow resistor can be used as a check valve and, more importantly, a passive flow regulator. Prototype devices have demonstrated regulation of nearly constant water flow rates from 0.21 to 1.2 ml/min, with variations less than 3%, under driving pressures that vary significantly from 100 to over 200 kPa. Three-dimensional fluid-structure interaction simulations have been performed to investigate the interactions between the fluid flow and flap deflection. The simulation results agree with the experimental data and provide insight into the device characteristics. Based on its single-layer planar configuration, passive operation over a large pressure range, and use of a flexible and inexpensive polymer, this self-adaptive variable flow resistor is well suited to flow control in lab-on-a-chip systems. [2006-0129] Index Terms--Flow regulator, fluid structure interaction (FSI), fluidic resistor, microfluidics, valve.