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Preparation of Environmentally Friendly Urea-Hexanediamine-Glyoxal(HUG)Resin Wood Adhesive

Journal of Renewable Materials 2024年第2期12卷 235-244页

作者： Qianyu Zhang Shi Chen Long Cao Hong Lei Antonio Pizzi Xuedong Xi Guanben Du Yunnan Key Laboratory of Wood Adhesives and Glue products College of Material Science and EngineeringSouthwest Forestry UniversityKunming650224China International Joint research center for Biomass Materials Southwest Forestry UniversityKunming650224China College of Chemical and Materials Engineering Zhejiang A&F UniversityHangzhou311300China LERMAB University of LorraineEpinal88000France

Using non-toxic,low-volatile glyoxal to completely replace formaldehyde for preparing urea-glyoxal(UG)resin adhesive is a hot research topic that could be of great interest for the wood ***,urea-glyoxal(UG)resins prepared by just using glyoxal instead of formaldehyde usually yields a lower degree of *** results in a poorer bonding performance and water resistance of UG resins.A good solution is to pre-react urea to preform polyurea molecules presenting already a certain degree of polymerization,and then to condense these with glyoxal to obtain a novel UG ***,in this present work,the urea was reacted with hexamethylene diamine to form a polyurea named HU,and then this was used to react it with different amounts of glyoxal to synthesize hexamethylenediamine-urea-glyoxal(HUG)polycondensation resins,and to use this for bonding *** results show that the glyoxal can well react with HU polyuria via addition and schiff base reaction,and also the HUG resin exhibits excellent bonding strength and water *** shear strength of the plywood bonded with this HUG at 160°C hot press temperature as high as 1.93 MPa,2.16 MPa and 1.61 MPa,respectively,which meets the requirement of the China national standard GB/T 9846-2015(≥0.7 MPa),and can be a good choice as a wood adhesive for industrial application.

关键词： Urea-glyoxal resin hexamethylene diamine wood adhesives water resistance

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Precipitation and anthropogenic activities regulate the changes of NDVI in Zhegucuo Valley on the southern Tibetan Plateau

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Journal of Mountain Science 2024年第2期21卷 607-618页

作者： ZHAO Wanglin WANG Hengying ZHANG Huifang ZHANG Lin School of Ecology and Environment Tibet UniversityLhasa 850000China Institute of Tibetan Plateau research Chinese Academy of SciencesBeijing 100101China southwest Survey and Planning Institute of National Forestry and Grassland Administration Kunming 650000China Monitoring center for Ecological Environment of Xizang Autonomous Region Lhasa 850000China

Whether climate change or anthropogenic activities play a more pivotal role in regulating vegetation growth on the Tibetan Plateau is still controversial.A better understanding on grassland changes at a fine scale may provide important guidance for local government policy and grassland *** two of the most reliable satellite NDVI products(MODIS NDVI and SPOT NDVI),we evaluated the dynamic of grasslands in the Zhegucuo valley on the southern Tibetan Plateau from 2000 to 2020,and analyzed its driving factors and relative influences of climate change and anthropogenic ***,the key indicators of climate change were assumed to be precipitation and *** main results were:(1)the grassland NDVI in Zhegucuo valley did not reflect a significant temporal change during the last 21 *** variation of precipitation during the early growing season(GSP)resembled that of NDVI,and the GSP was positively correlated with *** the pixel level,the partial correlation analysis showed that 37.79%of the pixels depicted a positive relationship between GSP and NDVI,while 11.32%of the pixels showed a negative relationship between temperature during the early growing season(GST)and NDVI.(2)In view of the spatial distribution,the areas mainly controlled by GSP were generally distributed in the southern part,while those affected by GST stood in the eastern part,mainly around the Zhegucuo lake where most population in Cuomei County settled down.(3)Decreasing NDVI trends were mainly occurred in alpine steppe at lower elevations rather than alpine meadow at higher elevations.(4)The residual trend(RESTREND)analysis further indicated that the anthropogenic activities played a more pivotal role in regulating the annual changes of NDVI rather than climate factors in this *** studies should pay more attention on climate extremes rather than the simple temporal ***,the influence of human activities on alpine grassland needs to be accessed and fully

关键词： Anthropogenic activities Climate change Precipitation Fencing Vegetation degradation

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Nutrition strategies to control post-weaning diarrhea of piglets: From the perspective of feeds

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Animal Nutrition 2024年第2期17卷 297-311页

作者： Qingsong Tang Tianyi Lan Chengyu Zhou Jingchun Gao Liuting Wu Haiyang Wei Wenxue Li Zhiru Tang Wenjie Tang Hui Diao Yetong Xu Xie Peng Jiaman Pang Xuan Zhao Zhihong Sun Laboratory for Bio-Feed and Molecular Nutrition College of Animal Science and Technology Southwest University Animal Breeding and Genetics Key Laboratory of Sichuan Province Sichuan Animal Science Academy Yibin Academy of southwest University

Post-weaning diarrhea(PWD) is a globally significant threat to the swine industry. Historically, antibiotics as well as high doses of zinc oxide and copper sulfate have been commonly used to control ***, the development of bacterial resistance and environmental pollution have created an interest in alternative strategies. In recent years, the research surrounding these alternative strategies and the mechanisms of piglet diarrhea has been continually updated. Mechanically, diarrhea in piglets is a result of an imbalance in intestinal fluid and electrolyte absorption and secretion. In general, enterotoxigenic Escherichia coli(ETEC) and diarrheal viruses are known to cause an imbalance in the absorption and secretion of intestinal fluids and electrolytes in piglets, resulting in diarrhea when Cl secretion-driven fluid secretion surpasses absorptive capacity. From a perspective of feedstuffs, factors that contribute to imbalances in fluid absorption and secretion in the intestines of weaned piglets include high levels of crude protein(CP), stimulation by certain antigenic proteins, high acid-binding capacity(ABC), and contamination with deoxynivalenol(DON) in the diet. In response, efforts to reduce CP levels in diets,select feedstuffs with lower ABC values, and process feedstuffs using physical, chemical, and biological approaches are important strategies for alleviating PWD in piglets. Additionally, the diet supplementation with additives such as vitamins and natural products can also play a role in reducing the diarrhea incidence in weaned piglets. Here, we examine the mechanisms of absorption and secretion of intestinal fluids and electrolytes in piglets, summarize nutritional strategies to control PWD in piglets from the perspective of feeds, and provide new insights towards future research directions.

关键词： Post-weaning diarrhea Fluid secretion Feed Nutritional regulation strategies Piglet

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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2024年

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences research Unit of Chemical Biology of natural Anti-Virus products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase SpeF and P450 monooxygenase SpeG, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, SpeF/SpeG metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-mA with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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Solid Tumor Inhibitory and other Constituents of Casimiroa tetrameria

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中国天然药物 2011年第5期9卷 334-337页

作者： XU Ya-Ming Maria del C. Ramirez-Ahumada Frederick A. Valenote A. A. Leslie Gunatilaka southwest center for natural products research and commercialization School of Natural Resources and the Environment The University of Arizona 250 E Valencia Road Tucson Arizona 85706-6800 USA Division of Hematology & Oncology Henry Ford Hospital Detroit Michigan 48202 USA

AIM:To isolate and characterize solid tumor inhibitory and other constituents from a bioactive extract of Casimiroa tetrameria((Rutaceae).METHODS:A crude extract of *** obtained from the US National Cancer Institute natural Product Repository and found to exhibit selective toxicity to solid tumor cells was subjected bioactivity-guided fractionation involving solvent-solvent partitioning,gel filtration,and *** structures of all isolated compounds were elucidated by spectroscopic analysis(NMR and MS) and/or by comparison with the reported *** 1 and 4-9 were evaluated for their solid tumor selective ***:Nine metabolites,including a new furanocoumarin,5-methoxy-8-(4'-acetoxy-3'-methylbut-2-eny-loxy)-psoralen(1),and the previously known compounds 2-9 were *** these the flavonoid zapotin(6),and N-benzoyltyramide derivatives 7 and 8 were found to be the active ***:Zapotin(6) is the most potent constituent of *** with solid tumor selectivity.

关键词： Casimiroa tetrameria Rutaceae Solid tumor selectivity Flavonoids Zapotin Furanocoumarins N-benzoyltyramides

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QTL analysis of leaf photosynthesis rate and related physiological traits in Brassica napus

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Journal of Integrative Agriculture 2015年第7期14卷 1261-1268页

作者： YAN Xing-ying QU Cun-min LI Jia-na CHEN Li LIU Lie-zhao College of Agronomy and Biotechnology Southwest University Biotechnology research center Southwest University

Rapeseed （Brassica napus L.） oil is the crucial source of edible oil in China. In addition, it can become a major renewable and sustainable feedstock for biodiesel production in the future. It is known that photosynthesis products are the primary sources for dry matter accumulation in rapeseed. Therefore, increasing the photosynthetic efficiency is desirable for the raise of rapeseed yield. The objective of the present study was to identify the genetic mechanism of photosynthesis based on the description of relationships between different photosynthetic traits and their quantitative trait loci （QTL） by using a recombinant inbred line （RIL） population with 172 lines. Specifically, correlation analysis in this study showed that internal CO2 concentration has negative correlations with other three physiological traits under two different stages. Totally, 11 and 12 QTLs of the four physiological traits measured at the stages 1 and 2 were detected by using a high-density single nu- cleotidepolymorphism （SNP） markers linkage map with composite interval mapping （CIM）, respectively. Three co-localized QTLs on A03 were detected at stage 1 with 5, 5, and 10% of the phenotypic variation, respectively. Other two co-localized QTLs were located on A05 at stage 2, which explained up to 12 and 5% of the phenotypic variation, respectively. The results are beneficial for our understanding of genetic control of photosynthetic physiological characterizations and improvement of rapeseed yield in the future.

关键词： Brassica napus photosynthesis quantitative trait loci (QTL)

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Diverse strategic approaches en route to Taxol total synthesis

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Chinese Chemical Letters 2022年第12期33卷 4957-4968页

作者： Zexian Li Jianfeng Zheng Wei-Dong Z.Li Sichuan Engineering research center for Biomimetic Synthesis of natural Drugs School of Life Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Taxol is one of the most famous diterpenoid natural products used in clinical cancer *** and its analogues are popular synthetic targets and have attracted worldwide attention over the past *** research efforts have already been made and ten groups have achieved the total synthesis of Taxol since *** mini-review summarized the recent highlights of divergent strategic approaches towards the chemical synthesis of Taxol's carbocyclic framework bearing a bridged eight-membered ring.

关键词： Taxol Total synthesis Biomimetic synthesis Linear strategy Convergent strategy

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The Study on Bamboo Microfibers Isolated by Steam Explosion and Their Comprehensive Properties

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Journal of Renewable Materials 2023年第6期11卷 2809-2822页

作者： Qiushi Li Ronggang Luo Yu Chen Jinhui Xiong Bei Qiao Xijuan Chai Linkun Xie Juan Wang Lianpeng Zhang Siqun Wang Guanben Du Kaimeng Xu Yunnan Provincial Key Laboratory of Wood Adhesives and Glued products Southwest Forestry UniversityKunming650224China International Joint research center for Biomass Materials Ministry of Science and TechnologySouthwest Forestry UniversityKunming650224China Key Laboratory for Forestry Resources Conversion and Utilization in the southwest Mountains of China Ministry of EducationSouthwest Forestry UniversityKunming650224China center for Renewable Carbon The University of TennesseeKnoxvilleTN37996USA

To overcome the shortage of wood resources as well as to develop novel natural fibers materials,the Chimonobambusa quadrangularis(CQ)and Qiongzhuea tumidinoda(QT)planted in southwest China were effectively isolated by the steam explosion(SE).The fine and uniform bamboo microfibers derived from CQ and QT were obtained,and their smallest average widths were 12.62μm and 16.05μm,*** effects of steam explosion on the micro-morphology,chemical composition,thermal stability,crystallinity,surface wettability,and mechanical properties of bamboo microfibers were comprehensively *** results showed that the relative content of cellulose in bamboo microfibers increased but the hemicellulose and lignin contents decreased after *** degrees of crystallinity for CQ and QT increased from 40.49%and 39.46%to 68.90%and 55.78%,*** thermal stability and surface hydrophilicity were also *** CQ microfibers had a maximum decomposition temperature of 2.79°C,a tensile strength of 58.54 MPa,an elongation at break of 0.6%,and a water contact angle of 2.7°higher than those of the QT microfibers.

关键词： Microfiber properties bamboo steam explosion Chimonobambusa quadrangularis Qiongzhuea tumidinoda

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A review on flexible solar cells

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Science China Materials 2024年第9期67卷 2717-2736页

作者： Shenglei Huang Cheng Qian Xingting Liu Liping Zhang Fanying Meng Zhu Yan Yinuo Zhou Junlin Du Bin Ding Jianhua Shi Anjun Han Wenjie Zhao Jian Yu Xin Song Zhengxin Liu Wenzhu Liu research center for New Energy Technology(RCNET) National Key Laboratory of Materials for Integrated CircuitsShanghai Institute of Microsystem and Information Technology(SIMIT)Chinese Academy of Sciences(CAS)Shanghai 201800China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China University of Chinese Academy of Sciences(UCAS) Beijing 100049China School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500China School of Materials Science and Engineering Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and ApplicationsChangzhou UniversityChangzhou 213164China Institute of Solid Mechanics Beihang UniversityBeijing 100191China

With the gradual progression of the carbon neutrality target,the future of our electricity supply will experience a massive increase in solar generation,and approximately 50%of the global electricity generation will come from solar generation by *** provides the opportunity for researchers to diversify the applications of photovoltaics(PVs)and integrate for daily use in the *** solar cell technology is the next frontier in solar PV and is the key way to achieve CO_(2)*** integration of PV technology with other fields will greatly broaden the development areas for the PV industry,providing products with higher added *** this paper,we reviewed the latest research progress on flexible solar cells(perovskite solar cells,organic solar cells,and flexible silicon solar cells),and proposed the future applications of flexible solar cell technology.

关键词： carbon neutrality flexible PVs perovskite solar cells organic solar cells flexible silicon solar cells

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Diversity, regeneration status and population structure of gum-and resin-bearing woody species in south Omo zone, southern Ethiopia

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Journal of Forestry research 2014年第2期25卷 319-328页

作者： Muhamed Adem Adefires Worku Mulugeta Lemenih Wubalem Tadesse Jürgen Pretzsch Madawalabu University Technical University of Dresden Institute of International Forestry and Forest Products Wondo Genet College of Forestry and natural Resources Ethiopian Institute of Agricultural research Forestry Research Sector

South Omo Administrative Zone in Ethiopia is home to 18 indigenous ethnic groups whose livelihood is vulnerable due to recurrent drought and degradation. Despite the preliminary observation showing the rich dry-forest resource base that, if sustainably managed could enhance livelihoods and biodiversity conservation, there is lack of empirical data on its current status. We conducted a study aiming at quantifying the population status of gum- and resin-bearing species in two randomly selected districts, Hamer and Bena-Tsemay. Seventy-five quadrats （35 at Hamer and 40 at Bena-Tsemay） each measuring 400 m2 were established along line transects to assess species diversity and equitability, density, frequency, dominance, importance value and population structure. We recorded a total of 27 woody species of 12 families and 14 genera. Fifteen species （9 at Hamer and 14 at Bena-Tsemay） of the genera Acacia, Boswellia, Commiphora and Sterculia, were identified as either major sources of commercial gums and resins or their adulterants. Gum- and resin-bearing species comprised 56% and 57% of species richness, 48% and 50% of total density per ha, 95% and 98% of basal area, and 64% and 56% of importance values at Hamer and Bena-Tsemay, respectively. Diversity of the entire woody species assemblage and of the gum- and resin-bearing species was slightly higher at Bena-Tsemay （H= 2.61, 1.4） than at Hamer （H＇= 2.48, 1.28）, respectively. The diversity and abundance of the resource base suggest potential for development of value-added commercialization of gum and resins to enhance livelihoods and encourage sustainable management of the forest at these study areas. We recorded, however, declining natural regeneration of most gum- and resin-bearing species, and this calls for integrated and participatory species management and landscape rehabilitation.

关键词： Acacia Boswellia Commiphora Sterculia gum and resins population status southern Ethiopia

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