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Seasonal and reproductive variation in chemical constituents of scent signals in wild giant pandas

Science China(Life Sciences) 2019年第5期62卷 648-660页

作者： Wenliang Zhou Yonggang Nie Yibo Hu Ronald R.Swaisgood Yaohua Zhang Dingzhen Liu Fuwen Wei Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering College of Life Sciences Beijing Normal University CAS Key Laboratory of Animal Ecology and Conservation Biology Institute of Zoology Chinese Academy of Sciences Center for Excellence in Animal Evolution and Genetics Chinese Academy of Sciences Institute for Conservation Research San Diego Zoo Global State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture Institute of Zoology Chinese Academy of Sciences University of Chinese Academy of Sciences

Seasonally reproducing animals show many behavioral and physiological changes during the mating period, including increased signaling for intrasexual competition and mate attraction. We collected 102 anogenital gland secretions(AGS) from marking trees in Foping Nature Reserve, and used gas chromatography mass spectrometry to analyze these chemical composition. Of these marks, all but one were from males, confirmed with DNA analysis. We found that several chemical constituents, especially volatile compounds, were present only during the mating season and that the relative abundance of many compounds changed as a function of breeding season, whereas nonvolatile compounds were lower in the mating season. This seasonal variation in chemical composition of AGS most likely plays an important role in governing giant panda reproduction, including mate location, attraction, and male-male competition. The chemical properties of many of these putative chemosignals—such as volatility and longevity—are suggestive of these roles, and undoubtedly contribute to successful reproduction for this species with a characteristically sophisticated chemical communication system. We also found a number of important differences between the chemical constituents of AGS from wild pandas and those found in previous studies with captive pandas, suggesting that inappropriate chemosignal composition may contribute to poor reproductive success in captive breeding programs.

关键词： giant panda chemical communication anogenital gland secretions chemical composition reproduction

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chemical weathering and chemical runoffs in the seashore granite hills in South China

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Science China Earth Sciences 2010年第8期53卷 1195-1204页

作者： GAO QuanZhou & TAO Zhen School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China School of Geography and Planning Sun Yat-sen University Guangzhou China

Surface runoffs and the contents of major ions and dissolved silicon were surveyed and analyzed based on weekly sampling for one year in a granite watershed of Zhuhai City, Guangdong Province. The results demonstrated that the slope runoff played an essential role in feeding the rivulet during precipitation, whereas the groundwater was more important for the rivulet in the non-raining stages. Dissolved silicon, Na+, HCO3-, and Clions constituted the major chemical components of the rivulet water. Atmospheric CO2 and H2SO4 sourced from the oxidation of pyrite were the main erosive mediums in the natural chemical weathering. Natural chemical weathering, the wet and dry deposition of sea-salt, and acids precipitation contributed approximately equal shares of anions to the rivulet water. The ratio of NO3- to SO42- was more than 1.0 in the runoff of the studied seashore watershed, whereas it is less than 1.0 in the Xijiang River that is adjacent to the study area. This implied that the chemical composition of runoff is controlled mainly by the differences in atmospheric acid precipitation caused by human activities and lithology within the catchments under the same bio-climate zone. The CO2 flux consumed by the rock chemical weathering processes within the seashore granite watershed in South China was (0.35-1.37)×105 mol km-2 a-1.

关键词： chemical weathering granite ion sea-salt acid deposition CO2

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chemical speciation code CHEMSPEC and its applications

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Science China Chemistry 2009年第11期52卷 2020-2032页

作者： WANG XiangYun CHEN Tao LIU ChunLi Beijing National Laboratory for Molecular Sciences Department of Applied ChemistryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The adsorption and migration behavior of a radionuclide in geological media heavily depends on its chemical forms in a given chemical environment.In order to predict the temporal and spatial distribution of radionuclides around a disposal site when its canister is damaged,it is necessary to develop coupled chemical speciation-solute transport models and relevant software.For that reason,we wrote a new chemical speciation program CHEMSPEC.In this paper,the principles and structure of CHEMSPEC are briefly described,and the strategy and algorithms that were used in this code are interpreted in some detail,such as the measures adopted to prevent divergence in iteratively solving the mass balance equations,the "predictor-corrector" algorithm for calculation of the number and quantities of solid species formed,and the alternate use of "freezing" and "defreezing" oxidation states in handling of co-existent redox and precipitation equilibria.Four examples are given to illustrate CHEMSPEC's features and capabilities.

关键词： chemical speciation modeling code structure algorithms high-level radioactive waste

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chemical Defense of Soft Coral Sinularia polydactyla from the Red Sea Against Marine Biofilm-Forming Bacteria

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Journal of Ocean University of China 2018年第6期17卷 1451-1457页

作者： ESKandER Rehab AL-SOFYANI Abdulmohsin A. EL-SHERBINY Mohsen M.O. BA-AKDAH Mohammad Abdulaziz SATHEESH Sathianeson Department of Marine Biology Faculty of Marine Sciences King Abdulaziz University

Soft corals are an important group of organisms that live in reef ecosystems. In this study, the chemical defense of soft coral Sinularia polydactyla against biofilm-forming bacteria was assessed. The soft coral S. polydactyla was collected from the Obhur creek of the Red Sea and the bioactive compounds were extracted under different conditions using methanol and hexane as solvents. Results revealed that the bioactive compounds produced by the soft coral S. polydactyla were active against the growth, hydrophobicity and extracellular polymeric substances production of the biofilm-forming bacteria. However, the damage or injury in soft coral tissue caused a decrease in the activity against biofilm-forming bacteria. GC-MS analysis revealed that sesquiterpenes were abundant in normal coral sample extract while cembranoids were abundant in damaged coral sample extracts. In general, the results indicated that the soft corals either under stress or with damage may not have a strong chemical defense against the colonizing marine organisms and competitors.

关键词： chemical ecology antifouling antibiofilm activity bioactive compound coral tissue damage

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chemical short-range order domain in bulk amorphous alloy and the prediction of glass forming ability

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Science China(Technological Sciences) 2003年第6期46卷 581-592页

作者：惠希东姚可夫寇宏超陈国良 State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China Mechanical Department Tsinghua University Beijing 100084 China

Short-range order domains of face central cubic Zr2Ni (F-Zr2Ni) and tetragonal Zr2Ni (T-Zr2Ni) type structure with a size about 1—3 nanometers were observed in bulk amorphous Zr52.5Cu17.9Ni14.6Al10Ti5 alloy by using HREM and nano-beam electron diffraction technique. A new thermodynamic model was formulated based on the concept of chemical short-range order (SCRO). The molar fractions of CSRO and thermodynamic properties in Ni-Zr, Cu-Zr, Al-Zr, Al-Ni, Zr-Ni-Al and Zr-Ni-Cu were calculated. According to the principle of maximum CSRO,GDthe opti-mum glass forming ability (GFA) compositions were predicted in binary and ternary alloys. These results were proved to be valid by the experimental data of crystallizing activation energy, DTx and XRD patterns. The TTT curves of Zr-Ni-Cu alloys calculated based on CSRO model shows that the lowest critical cooling rate GFA is in the order of 100 K/s, which is close to the practical cooling rate for the preparation of Zr-based BMG alloys.

关键词： bulk metallic glasses, chemical short-range order domain, glass forming ability, thermodynamic model.

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Neuroprotection mediated by natural products and their chemical derivatives

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Neural Regeneration Research 2020年第11期15卷 2008-2015页

作者： Fei Fei Ning Su Xia Li Zhou Fei Department of Ophthalmology Xijing Hospitalthe Fourth Military Medical UniversityXi’anShaanxi ProvinceChina Department of Radiation Oncology Xijing Hospitalthe Fourth Military Medical UniversityXi’anShaanxi ProvinceChina Department of Neurosurgery Xijing Hospitalthe Fourth Military Medical UniversityXi’anShaanxi ProvinceChina

Neuronal injuries can lead to various diseases such as neurodegenerative diseases,stroke,trauma,ischemia and,more specifically,glaucoma and optic neuritis.The cellular mechanisms that regulate neuronal death include calcium influx and calcium overload,excitatory amino acid release,oxidative stress,inflammation and microglial activation.Much attention has been paid to the effective prevention and treatment of neuroprotective drugs by natural products.This review summarizes the neuroprotective aspects of natural products,extracted from Panax ginseng,Camellia sinensis,soy and some other plants,and some of their chemical derivatives.Their antioxidative and anti-inflammatory action and their inhibition of apoptosis and microglial activation are assessed.This will provide new directions for the development of novel drugs and strategies to treat neurodegenerative diseases.

关键词： antioxidant effect brain injuries Camellia sinensis chemical derivatives curcumin genistein natural products neurodegenerative diseases neuroprotection Panax

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Investigation of Single-Wall MoS_2 Monolayer Flakes Grown by chemical Vapor Deposition

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Nano-Micro Letters 2016年第1期8卷 70-79页

作者： Nihan Kosku Perkgoz Mehmet Bay Department of Electrical and Electronics Engineering Faculty of Engineering Anadolu University

Recently, two-dimensional monolayer molybdenum disulfide(MoS_2), a transition metal dichalcogenide, has received considerable attention due to its direct bandgap, which does not exist in its bulk form, enabling applications in optoelectronics and also thanks to its enhanced catalytic activity which allows it to be used for energy harvesting. However,growth of controllable and high-quality monolayers is still a matter of research and the parameters determining growth mechanism are not completely clear. In this work, chemical vapor deposition is utilized to grow monolayer MoS_2 flakes while deposition duration and temperature effect have been systematically varied to develop a better understanding of the MoS_2 film formation and the influence of these parameters on the quality of the monolayer flakes. Different from previous studies, SEM results show that single-layer MoS_2 flakes do not necessarily grow flat on the surface, but rather they can stay erect and inclined at different angles on the surface, indicating possible gas-phase reactions allowing for monolayer film formation. We have also revealed that process duration influences the amount of MoO_3/MoO_2 within the film network. The homogeneity and the number of layers depend on the change in the desorption–adsorption of radicals together with sulfurization rates, and, inasmuch, a careful optimization of parameters is crucial. Therefore, distinct from the general trend of MoS_2 monolayer formation, our films are rough and heterogeneous with monolayer MoS_2 nanowalls. Despite this roughness and the heterogeneity, we observe a strong photoluminescence located around 675 nm.

关键词： Monolayer chemical vapor deposition Two-dimensional materials Molybdenum disulfide(MoS2)

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Global identification of chemical constituents and rat metabolites of Si-Miao-Wan by liquid chromatography-electrospray ionization/ quadrupole time-of-flight mass spectrometry

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Chinese Journal of Natural Medicines 2017年第7期15卷 550-560页

作者： LU Jin-Jin HU Xue-Wen LI Ping CHEN Jun State Key Laboratory of Natural Medicines China Pharmaceutical University Nanjing 210009 China

Si-Miao-Wan(SMW), a tradiational Chinese medicinal formula consisting of Atractylodis Rhizoma, Phellodendri Chinensis Cortex, Coicis Semen, and Achyranthis Bidentatae Radix, has been used for the treatment of gout and gouty arthritis for many years. In the present study, a liquid chromatography quadrupole-time-of-flight mass spectrometry(LC-Q-TOF/MS) method was established to identify the multiple constituents of SMW and its metabolites in rat biological samples after oral administration. A total of 48 compounds in SMW, including 21 alkaloids, 12 organic acids, 2 terpenes, 3 lactones, 2 phytosterols, and 8 other compounds, were tentatively characterized with the diagnostic-ion filtering strategy. Based on the diagnostic ions applied to identify compounds in SMW, 28 prototype compounds and 10 metabolic compounds were detected in the biological samples. This was the first comprehensive drug metabolism investigation of SMW in rats. The developed method could be a useful means for identifying the multi-components in SMW and the metabolic components. The results may help explore the possible metabolic processes and mechanism of action for SMW in vivo.

关键词： Si-Miao-Wan LC-Q-TOF/MS chemical constituents Metabolites

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chemical Intervention on Staphylococcus aureus Virulence

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Chinese Journal of Chemistry 2019年第2期37卷 183-193页

作者： Lin-Lin Zhou Cai-Guang Yang State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University of the Chinese Academy of Sciences Beijing 100049China

Resistance to conventional antibiotics has raised worldwide attention. Notably, Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most life-threatening health concerns. Although effective against bacterial infections, conventional antibiotics have also showed a series of side effects such as gut microbiota imbalance.

关键词： chemical Intervention Staphylococcus aureus Virulence

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A study of fire propagation in coal seam with numerical simulation of heat transfer and chemical reaction rate in mining field

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International Journal of Mining Science and Technology 2019年第6期29卷 873-879页

作者： Moisés Oswaldo Bustamante Rúa Alan José Daza Aragón Pablo Bustamante Baena National University of Colombia Cr 65 # 63 20 CIMEX Minerals Institute

Spontaneous combustion of coal is a problem that affects the mining operation and generates environ-mental,economic,social and geotechnical impacts.This phenomenon has been divided into two pro-cesses:ignition and propagation.Fire propagation develops in coal seams because of a set of factors such as direction and wind speed,fracturing and temperature.In this work,heat transfer and chemical kinetics are studied from conservation equations of energy and species,respectively,using the software COMSOL Multiphysics to simulate the propagation of fires in coal seams.Two possible scenarios were analyzed that usually occur in the walls of the coal seams,such as fire focus and fire complete screens.It was found that the propagation kinetics of the fire changes depending on the temperature,the fractur-ing of rock mass and the area of fire influence.For temperature values lower than 300℃,there is con-sumption around 250 cm^3/h,values around 700℃,the consumption is 1500 cm^3/h,and for fires of 1200℃ have values of 3000 cm^3/h.Depending on the speed of propagation can vary from 4 to 17cm/day,considering on the level and fracturing of the final wall of the open pit.

关键词： Spontaneous combustion of coal Open pit mines Simulation Heat transfer chemical reaction COMSOL

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