Distribution and metabolism of ascorbic acid in pear fruits (Pyrus pyrifolia Nakai cv. Aikansui)

Ascorbate accumulation levels, distribution and key enzyme activities involved in synthesizing via Smirnoff-Wheeler pathway and recycling in different pear fruit tissues during development were studied. Results show that the ascorbate contents increased with the fruit development, and reached the highest titers in 30 days after anthesis (DAA), then decreased and maintained a level. The higher contents of ascorbate in the peel of pear fruit were observed, which results from a combination of higher activities of L-galactose dehydrogenase (GalDH) and L-galactono-1,4-lactone (GalLDH) involving ascorbate biosynthesis and higher dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) activities used to recycle ascorbate. Exogenous feeding of ascorbate synthesis precursors demonstrated that the peel had stronger capability of de novo ascorbate biosynthesis via Smirnoff-Wheeler pathway and uronic acid pathway whereas the flesh and core had lower capability for ascorbate synthesis. These results suggest that the pear fruit is able to cause de novo ascorbate biosynthesis and the peel had higher capability for ascorbate biosynthesis than the flesh and core.Keywords: Pyrus pyrifolia, ascorbate, biosynthesisAfrican Journal of Biotechnology Vol. 12(16), pp. 1952-196

The long noncoding RNA LINC15957 regulates anthocyanin accumulation in radish

Radish (Raphanus sativus L.) is an important root vegetable crop belonging to the Brassicaceae family. Anthocyanin rich radish varieties are popular among consumers because of their bright color and high nutritional value. However, the underlying molecular mechanism responsible for skin and flesh induce anthocyanin biosynthesis in transient overexpression, gene silencing and transcriptome sequencing were used to verify its function in radish anthocyanin accumulation, radish remains unclear. Here, we identified a long noncoding RNA LINC15957, overexpression of LINC15957 was significantly increased anthocyanin accumulation in radish leaves, and the expression levels of structural genes related to anthocyanin biosynthesis were also significantly increased. Anthocyanin accumulation and expression levels of anthocyanin biosynthesis genes were significantly reduced in silenced LINC15957 flesh when compared with control. By the transcriptome sequencing of the overexpressed LINC15957 plants and the control, 5,772 differentially expressed genes were identified. A total of 3,849 differentially expressed transcription factors were identified, of which MYB, bHLH, WD40, bZIP, ERF, WRKY and MATE were detected and differentially expressed in the overexpressed LINC15957 plants. KEGG enrichment analysis revealed the genes were significant enriched in tyrosine, L-Phenylalanine, tryptophan, phenylpropanol, and flavonoid biosynthesis. RT-qPCR analysis showed that 8 differentially expressed genes (DEGs) were differentially expressed in LINC15957-overexpressed plants. These results suggested that LINC15957 involved in regulate anthocyanin accumulation and provide abundant data to investigate the genes regulate anthocyanin biosynthesis in radish

A Development and Application of the Fretting Fatigue Test Apparatus

Fretting fatigue occurs in contacting parts which are subjected to fluctuating loads and very small sliding movements at the same time. Fretting fatigue can significantly reduce the fatigue life of materials. In this investigation, a new device is introduced, which performed using a combination of a servo-hydraulic push-pull fatigue testing machine and a specially designed jig for appropriate positioning of pads. The axial and contact loads are measured by load cells. The functionality of the device is examined by making a comparison between fretting fatigue lives and plain fatigue lives of a number of ZL702A aluminum alloy specimens. The main advantages of the device are its simplicity and cheapness. It can be developed further for high and low temperature tests in future

A Development and Application of the Fretting Fatigue Test Apparatus

Fretting fatigue occurs in contacting parts which are subjected to fluctuating loads and very small sliding movements at the same time. Fretting fatigue can significantly reduce the fatigue life of materials. In this investigation, a new device is introduced, which performed using a combination of a servo-hydraulic push-pull fatigue testing machine and a specially designed jig for appropriate positioning of pads. The axial and contact loads are measured by load cells. The functionality of the device is examined by making a comparison between fretting fatigue lives and plain fatigue lives of a number of ZL702A aluminum alloy specimens. The main advantages of the device are its simplicity and cheapness. It can be developed further for high and low temperature tests in future

Identification and Optimization of County-Level Ecological Spaces under the Dual-Carbon Target: A Case Study of Shaanxi Province, China

County-level ecological space, as a crucial level in optimizing the land spatial system, plays a pivotal role in “undertaking superior planning and guiding subordinate implementation”. From a spatial optimization perspective, effectively implementing the dual-carbon goal by increasing carbon sinks in specific ecological space units is essential. This study focused on 107 districts and counties in Shaanxi Province, China, aiming to construct a comprehensive multivariate identification system for ecological space under the dual-carbon target based on an analysis of the spatiotemporal distribution characteristics and driving factors of county-level carbon sinks. Furthermore, by analyzing the ecological spatial distribution pattern, carbon sink land structure, and county clustering characteristics, the study explored differential optimization strategies for ecological spaces of different county types to enhance carbon sinks in the ecosystem. The results demonstrated that: (1) From 2000 to 2020, the total carbon sink in Shaanxi Province exhibited an initial increase followed by a decrease, with a decline from 864.39 × 104 t to 863.21 × 104 t. The county-level distribution of total carbon sink displayed significant spatial heterogeneity, with an overall pattern of south > north > central. (2) The interaction among factors enhanced the explanatory power for spatial differentiation of county-level carbon sinks compared to individual factors, exerting an important impact on the spatial distribution pattern of carbon sinks. (3) The distribution of ecological space in Shaanxi Province was highly uneven, with the core ecological space primarily concentrated in the southern and north-central regions. The proportions of low carbon sink (Type I), medium carbon sink (Type II), and high carbon sink (Type III) counties were 35.51%, 18.69%, and 45.80%, respectively. For different types of county-level ecological spaces, this study proposed a differentiated optimization strategy aimed at reducing carbon emissions and enhancing carbon sink. The results will provide theoretical and technical support for regional ecological construction and land spatial optimization, holding significant practical implications for achieving the dual-carbon goal and addressing climate change

Perceptions of Cultural Ecosystem Services in Urban Parks Based on Social Network Data

The value of a cultural ecosystem service depends on the perception of different cultural service categories. However, the data sources used in research on the perception of cultural service have limitations that mainly depend on social investigation, leading to slow progress in cultural service evaluation. With the advent of the era of network big data, social media provides a new data source for the study of cultural ecosystem service perception, so that the study of these services is expected to make new breakthroughs. Using search crawler software, this paper reviewed 7257 online comments related to 19 city parks in Xuzhou City, China. With the help of Rost Content mining semantic analysis software, the comment sentences were divided into keywords, and the Delphi expert method was used to classify these keywords. Thus, a cultural service perception database was established. Through statistical analysis, with the help of ArcGIS software, various cultural services were analyzed. The results showed that (1) the cultural services of urban parks could be divided into seven types (i.e., aesthetics, recreation, sports, inspiration, education, cultural heritage, and spiritual satisfaction) using social network comment data. (2) High-frequency keywords of online comment data can serve as the core basis during an analysis of the perception of cultural services by visitors of city parks. However, a large gap exists in the number of high frequency keywords in different parks. For example, Yunlong Lake Park has 2887 keywords, while Kuaizai Ting Park has only 33. (3) Differences exist in the perception of cultural service in urban parks, the park’s scale, and characteristics determine the visitor’s cultural service perception level. The aesthetic and recreation types were the most easily perceived, and 68% and 63% parks have the above two perceptual records, respectively. Therefore, the social media comment data has the ability to document perception of each park’s cultural service type and its differences, which can serve as the cultural ecosystem service perception as well as the valuation data source, to supplement the social investigation

Stable Characteristics Optimization of Anti-Symmetric Cylindrical Shell with Laminated Carbon Fiber Composite

This paper proposes a multi-objective optimization model for anti-symmetric cylindrical shell in the bionic gripper structure. Here, the response surface method is used to establish multiple surrogate models of the anti-symmetric cylindrical shell, and the non-dominated sorting genetic algorithm-II (NSGA-II) is used to optimize the design space of the anti-symmetric cylindrical shell; the design points of the anti-symmetric cylindrical shell are verified by experimental methods. The optimization goals are that the first steady state transition load (the transition process of the bionic gripper structure from the open state to the closed state) of the anti-symmetric cylindrical shell is minimized, and the second steady state transition load (the transition process of the bionic gripper structure from the closed state to the open state) is the largest. At the same time, in order to prevent stable instability caused by stress concentration in the second steady state of the anti-symmetric cylindrical shell, the maximum principal plane stress is given as the constraint condition. The validity of the optimization results is verified by finite element and experimental methods. Due to the stable transition load of the anti-symmetric cylindrical shell being significantly larger than that of the orthogonal laminated plate, therefore, the anti-symmetric cylindrical shell has potential application prospects in the application of deformable structures and bionic structures that require composite functions such as having light weight, high strength, and large clamping force. The novelty of this paper lies in the multi-objective optimization of the application of the antisymmetric bistable cylindrical shell in the bionic gripper structure

Assessing the Changes of Ecosystem Services in the Nansi Lake Wetland, China

Wetlands provide many essential ecosystem services for human well-being. The ecological assessment of wetland ecosystem services is problematic and thus is an important focus in the field of ecological research. In this study, an ecological assessment system containing the ecosystem product value, ecosystem regulation service value, and ecosystem cultural service value was established to calculate the gross ecosystem product in the Nansi Lake Wetland, China. Based on remote sensing images, field studies, and literature reviews, the gross ecosystem product was estimated for the years 1985, 1992, 2005, 2011, and 2017. The results showed that the gross ecosystem product of the Nansi Lake Wetland increased from 40.91 × 108 USD in 1985 to 46.28 × 108 USD in 2017. The gross ecosystem product of the altered wetlands increased by about 8.5 times with a rising linear relationship, while natural wetlands presented a nonlinear relationship. Furthermore, except for the changes in climatic condition, anthropogenic interference factors such as coal mining activities, farming practices, and government policies have promoted significant services in the Nansi Lake Wetland over the past 30 years. This study could provide important insight into the ecological assessment of wetland ecosystems and thus inform policy for the protection and better use of wetland resources

Kinetics of Co-Gasification of Low-Quality Lean Coal and Biomass

The co-gasification behaviors of composite samples of biomass and lean coal were investigated under a CO2 atmosphere. The composite behaviors were determined based on thermogravimetric analysis and the Coats-Redfern method. These methods were used to analyze the kinetics of the processes. The results showed that the temperature ranges of the lean coal, biomasses, and the gasification ability of each biomass were different, and the coordination effects of each biomass varied. The addition of alkali metals had little influence on the pyrolysis efficiency and the peak temperature of composite samples of soybean stalk and lean coal, but it did promote gasification. In the processes of pyrolysis and gasification, composite samples of soybean stalk and lean coal exhibited lower activation energies than unmixed samples, but there was no significant enhancement with the extra alkali metal