Variations of Urban Thermal Risk with Local Climate Zones.

Due to the differences in land cover and natural surroundings within cities, residents in various regions face different thermal risks. Therefore, this study combined multi-source data to analyze the relationship between urban heat risk and local climate zones (LCZ). We found that in downtown Shenyang, the building-type LCZ was mainly found in urban centers, while the natural- type LCZ was mainly found in suburbs. Heat risk was highest in urban centers, gradually decreasing along the suburban direction. The thermal risk indices of the building-type LCZs were significantly higher than those of the natural types. Among the building types of LCZs, LCZ 8 (open middle high-rise) had the highest average thermal risk index (0.48), followed by LCZ 3 (0.46). Among the natural types of LCZs, LCZ E (bare rock and paved) and LCZ F (bare soil and sand) had the highest thermal risk indices, reaching 0.31 and 0.29, respectively. This study evaluated the thermal risk of the Shenyang central urban area from the perspective of LCZs and combined it with high-resolution remote sensing data to provide a reference for thermal risk mitigation in future urban planning.

Influence of Different Pretreatment Steps on the Ratio of Phenolic Compounds to Saccharides in Soluble Polysaccharides Derived from Rice Straw and Their Effect on Ethanol Fermentation.

The complex structure of rice straw is such that its bioconversion requires multiple physical and chemical pretreatment steps. In this study, it was found that a large amount of soluble polysaccharides (SPs) are formed during the pretreatment of straw. The yield of NaOH-based SPs (4.8%) was much larger than that of ball-milled SPs (1.5%) and H2SO4-based SPs (1.1%). For all the pretreatments, the ratio of phenolic compounds to saccharides (P/S) for each type of SPs increased upon increasing the concentration of ethanol in the order of 90% > 70% > 50%. The yield of NaOH-based SPs was much higher than that of acid-based and ball-milled SPs. The changes in the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power assay (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) of SPs follow the same rule, i.e., the higher the P/S ratio, the higher the antioxidant values of the SPs. The flow cytometry and laser scanning microscopy results show that the P/S ratio can significantly influence the effect of SPs on microbial growth and cell membrane permeability. Upon varying the ethanol concentration in the range of 50-90%, the P/S ratio increased from 0.02 to 0.17, resulting in an increase in the promoting effects of the SPs on yeast cell growth. Furthermore, H2O2, NAD+/NADH, and NADP+/NADPH assays indicate that SPs with a high P/S ratio can reduce intracellular H2O2 and change the intracellular redox status.

Antibacterial Effect of Phenolic Acids Derived from Rice Straw and in Combination with Antibiotics Against Escherichia coli.

Many studies have demonstrated that natural plant extracts have inhibitory effects on microorganisms. The purpose of this study was to investigate the inhibitory effect of phenolic acids from rice straw (PAs) on Escherichia coli and their synergistic effect in combination with antibiotics. PAs can inhibit the growth of E. coli effectively by inducing the formation of H2O2; PA-treated cells had a tenfold greater intracellular H2O2 concentration than the control group. The synergistic effect caused by the interaction of PAs and antibiotics on inhibiting the growth of E. coli was significant. This effect may be caused by a PA-induced change in the permeability of E. coli cell membrane. The treatment with PAs made the extracellular K+ concentration reached 15 mg/L within 30 min, while the K+ concentration in the control group was very low and did not change significantly over time. Similarly to the extracellular K+, the extracellular protein concentration exceeded 150 mg/L in the PA treatment group, while it remained very low in the control group. Due to the increased cell permeability, more antibiotics can enter the cell. Hence, this study may provide a novel method of improving the safe use of antibiotics.

Oligosaccharides in straw hydrolysate could improve the production of single-cell protein with Saccharomyces cerevisiae.

BACKGROUND: Using agricultural wastes to produce single-cell proteins (SCP) can reduce production costs effectively. The aims of this study were to investigate the effects of enzyme loading on the components of rice straw (RS) hydrolysate and their effects on the growth of yeast. RESULTS: At the same glucose concentration, the dry weight of cells produced in the hydrolysate was 2.89 times higher than that in 2 g L-1 yeast extract (YE) medium, indicating that the hydrolysate was a suitable substrate for yeast growth. Ethanol precipitation followed by analysis showed that there were many oligosaccharides in the hydrolysate. The amount of cellulase had an important effect on the production of monosaccharides but had a smaller effect on the amounts and compositions of oligosaccharides. Adding oligosaccharides to the medium had no effect on ethanol production, but it promoted yeast growth and increased SCP production effectively. The results indicate that oligosaccharides were an important growth factor for yeast in the hydrolysate. Compared with YE medium, the cost of the medium with the hydrolysate was reduced by 68.47% when the same dry cell weight was obtained. CONCLUSION: Oligosaccharides in the hydrolysate can improve SCP production with low nutrient cost. This finding could reduce the amounts of cellulase required during saccharification and nutrients during culture, providing a new low-cost method for SCP production. © 2021 Society of Chemical Industry.

Assessment of changes in environmental factors in a tourism-oriented Island.

Tourism development has influenced industrial structure changes and has become a major driving force for China's new urbanization. However, the development will negatively impact natural resources and the ecological environment and will become an essential driving factor for land use change. Therefore, understanding the impact of tourism urbanization is crucial for sustainable local development. This study selected the Dachangshan Island in the Changhai County, Dalian, China, as the study area, because it is the only coastal island-type border county in China. During the study period, changes in local environmental factors were analyzed based on land use data, Landsat 5 and Landsat 8 data of 2009, 2014, and 2019. The results showed that: (1) the overall land surface temperature (LST) in the research region shows an increasing trend; the LST in 2014 and 2019 increased by 6.10 and 5.94 °C, respectively, compared with 2009. With respect to specific land types, impervious surfaces maintained a high land surface temperature (25.44, 32.38, and 31.86); however, surface temperatures for cropland, forest, grassland, and water bodies remained stable. (2) The land use land cover (LULC) change analysis from 2009-2019 indicates that impervious surfaces and cropland increased by 0.5653 km2 and 0.9941 km2, while the areas of forest, grassland, and water bodies decreased. The results also showed that forests (-1.3703 km2) are most affected by urbanization. (3) The results of the landscape index calculation showed that the variation at the patch scale is different for different LULC types. The patch density of impervious surfaces decreased, but the aggregation index increased over time, while the patch density of the forest increased continuously. At the landscape scale, overall patch type and distribution remained stable. The purpose of this study is to explore the environmental changes of islands and provide a reference for the sustainable development of islands.

Transient characteristics of universal cells on human-induced pluripotent stem cells and their differentiated cells derived from foetal stem cells with mixed donor sources.

INTRODUCTION: It is important to prepare 'hypoimmunogenic' or 'universal' human pluripotent stem cells (hPSCs) with gene-editing technology by knocking out or in immune-related genes, because only a few hypoimmunogenic or universal hPSC lines would be sufficient to store for their off-the-shelf use. However, these hypoimmunogenic or universal hPSCs prepared previously were all genetically edited, which makes laborious processes to check and evaluate no abnormal gene editing of hPSCs. METHODS: Universal human-induced pluripotent stem cells (hiPSCs) were generated without gene editing, which were reprogrammed from foetal stem cells (human amniotic fluid stem cells) with mixing 2-5 allogenic donors but not with single donor. We evaluated human leucocyte antigen (HLA)-expressing class Ia and class II of our hiPSCs and their differentiated cells into embryoid bodies, cardiomyocytes and mesenchymal stem cells. We further evaluated immunogenic response of transient universal hiPSCs with allogenic mononuclear cells from survival rate and cytokine production, which were generated by the cells due to immunogenic reactions. RESULTS: Our universal hiPSCs during passages 10-25 did not have immunogenic reaction from allogenic mononuclear cells even after differentiation into cardiomyocytes, embryoid bodies and mesenchymal stem cells. Furthermore, the cells including the differentiated cells did not express HLA class Ia and class II. Cardiomyocytes differentiated from transient universal hiPSCs at passage 21-22 survived and continued beating even after treatment with allogenic mononuclear cells.

The design of a thermoresponsive surface for the continuous culture of human pluripotent stem cells.

Commonly, stem cell culture is based on batch-type culture, which is laborious and expensive. We continuously cultured human pluripotent stem cells (hPSCs) on thermoresponsive dish surfaces, where hPSCs were partially detached on the same thermoresponsive dish by decreasing the temperature of the thermoresponsive dish to be below the lower critical solution temperature for only 30 min. Then, the remaining cells were continuously cultured in fresh culture medium, and the detached stem cells were harvested in the exchanged culture medium. hPSCs were continuously cultured for ten cycles on the thermoresponsive dish surface, which was prepared by coating the surface with poly(N-isopropylacrylamide-co-styrene) and oligovitronectin-grafted poly(acrylic acid-co-styrene) or recombinant vitronectin for hPSC binding sites to maintain hPSC pluripotency. After ten cycles of continuous culture on the thermoresponsive dish surface, the detached cells expressed pluripotency proteins and had the ability to differentiate into cells derived from the three germ layers in vitro and in vivo. Furthermore, the detached cells differentiated into specific cell lineages, such as cardiomyocytes, with high efficiency.