438 research outputs found
Data for: The intra- and inter-annual responses of soil respiration to climate extremes in a semiarid grassland
No full textNo
sj-pdf-1-ppc-10.1177_09673911221107292 – Supplemental Material for Design and synthesis of high-performance poly(amide-imide) for multifunctional electromagnetic interference shielding films
No full textSupplemental Material, sj-pdf-1-ppc-10.1177_09673911221107292 for Design and synthesis of high-performance poly(amide-imide) for multifunctional electromagnetic interference shielding films by Changlong Zhuang, Yanbin Wang, Chengbi Chang, Zicheng Fan, Shuhan Hou, Chen Zhou, Hao Dong, Leier Xia, Zhonglin Luo and Biaobing Wang in Polymers and Polymer Composites</p
Catalyst-free photocyclopropanation of dibromomalonates with alkenes: an approach to multisubstituted cyclopropanes
Get PDFWe report herein a novel photocyclopropanation of dibromomalonates with alkenes in the presence of Hünig base. This protocol provides an environmentally benign approach for the synthesis of multisubstituted cyclopropanes, since no catalyst is required. The Photo-induced Electron Transfer (PET) from Hünig base to dibromomalonate is the key process during this transformation
Visible light induced oxidative hydroxylation of boronic acids
No full textWe report herein a visible light-induced aerobic oxidative hydroxylation of boronic acids. The reaction employed 7H-benzo[c]thioxanthen-7-one as metal-free catalyst and dimethyl carbonate as green solvent. Scale-up experiment was achieved using 0.1 mol% catalyst in a good yield with column-free purification. This reaction showed great green chemistry features and potential in synthetic applications.</p
Developing force field parameters for water interacting with graphene and graphene-like materials
Get PDFConfined water can have properties dramatically different from bulk water, and these properties can be used to develop unique functionality at the nanoscale. For example, fast water transport, rotation-translation coupling, and fast rotationalmotion have been observed in graphitic carbon-based nano structures, which enables various applications like energy storage and seawater desalination. The explosive studies on graphene have sparked new interests towards graphene-analogous materials including hexagonal boron nitride (hBN) and molybdenum disulfide (MoS2). Compared to graphene, the graphene-analogous materials possess non-zero bandgap, chemical inertness, and biological compatibility. The graphene-analogous materials are promising materials, complementary to graphene, for high-temperature, biomedical and nanofluidic applications. We would like to understand and optimize graphene and graphene-analogous materials in these applications.
The study of graphene and graphene-analogous materials at the atomic level requires accurate force field parameters to describe the water-surface interaction. We begin with benchmark quality first principles quantum Monte Carlo (QMC) calculations on the interaction energy between water and surface, which are used to validate random phase approximation (RPA) calculations. We then proceed with RPA to derive force field parameters, which are used to simulate properties like water contact angle on the surface, attaining a value within the experimental uncertainties. This work demonstrates that end-to-end multiscale modeling, starting at detailed many-body quantum mechanics, and ending with macroscopic properties, with the approximations controlled along the way, is feasible for these systems.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-08-01The student, Yanbin Wu, accepted the attached license on 2016-07-01 at 11:25.The student, Yanbin Wu, submitted this Dissertation for approval on 2016-07-01 at 11:32.This Dissertation was approved for publication on 2016-07-05 at 09:40.DSpace SAF Submission Ingestion Package generated from Vireo submission #9740 on 2016-11-10 at 12:24:48Made available in DSpace on 2016-11-10T18:39:15Z (GMT). No. of bitstreams: 3
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Characteristics and trends of grassland degradation research
Get PDFPurpose Grasslands are the largest type of terrestrial ecosystem on the earth, providing rich and unique ecosystem services.
However, climate change and human activities have triggered a global degradation of grasslands, which has become a major
ecological crisis. In this study, a scientometric analysis was performed to explore the hotspots and frontiers of global grassland
degradation research.
Materials and methods Two methods involving visualization were used to analyze these data: document co-citation analysis
and burst analysis based on the papers indexed in the Web of Science (WOS) during 1970–2020.
Results and discussion A total of 3580 research papers related to grassland degradation research and 54,666 references were
included. The results showed that Harris’s paper in 2010 had the strongest burst value of 26.2, far larger than any other,
which shows that this paper was a turning point in the research process. The document co-citation network was divided into
14 main theme clusters. The most influential and emerging research theme clusters were including alpine meadow, grazing
exclusion, alpine region, and human activities. Alpine meadow was the largest cluster lasting from 2010 to 2020, indicating
that this topic is still active in grassland degradation research. Furthermore, research focus has transferred toward grasslands
in Qinghai-Tibetan Plateau. The topic of grazing exclusion is both classic and currently active as it lasted as a research hotspot
for 15 years (2004–2018). However, the extent and state of grazing effects research are unclear.
Conclusions As the first scientometric review on grassland degradation research, our study identified the research hotspots
and their shifts over the past 50 years, pointing to some potential research frontiers in the future. The scientometric analysis
is a useful tool for a quantitative evaluation of research hotspots and trends of global grassland degradation
Extreme-duration drought impacts on soil CO2 efflux are regulated by plant species composition
No full textAims:
Long-duration drought can alter ecosystem plant species composition with subsequent effects on carbon cycling. We conducted a rainfall manipulation field experiment to address the question: how does drought-induced vegetation change, specifically shrub encroachment into grasslands, regulate impacts of subsequent drought on soil CO2 efflux (Rs) and its components (autotrophic and heterotrophic, Ra and Rh)?
Methods:
We conducted a two-year experiment in Inner Mongolia plateau, China, using constructed steppe communities including graminoids, shrubs and their mixture (graminoid + shrub) to test the effects of extreme-duration drought (60-yr return time) on Rs, Rh and Ra.
Results:
Our results indicated that extreme-duration drought reduced net primary production, with subsequent effects on Rs, Rh and Ra in all three vegetation communities. There was a larger relative decline in Ra (35–54%) than Rs (30–37%) and Rh (28–35%). Interestingly, we found Rs in graminoids is higher than in shrubs under extreme drought. Meanwhile, Rh declines were largest in the shrub community. Although Ra and Rh both decreased rapidly during drought treatment, Rh recovered quickly after the drought, while Ra did not, limiting the Rs recovery.
Conclusions:
This study suggests that plant species composition regulates several aspects of soil CO2 efflux response to climate extremes. This regulation may be limited by above- and below-ground net primary production depending on soil water availability. The results of this experiment address a critical knowledge gap in the relationship between soil respiration and plant species composition. With shrub encroachment into grasslands, total soil respiration is reduced and can partly offset the effect of reduction in productivity under drought stress.No Full Tex
A data-driven crop model for maize yield prediction
Get PDFAccurate estimation of crop yield predictions is of great importance for food security under the impact of climate change. We propose a data-driven crop model that combines the knowledge advantage of process-based modeling and the computational advantage of data-driven modeling. The proposed model tracks the daily biomass accumulation process during the maize growing season and uses daily produced biomass to estimate the final grain yield. Computational studies using crop yield, field location, genotype and corresponding environmental data were conducted in the US Corn Belt region from 1981 to 2020. The results suggest that the proposed model can achieve an accurate prediction performance with a 7.16% relative root-mean-square-error of average yield in 2020 and provide scientifically explainable results. The model also demonstrates its ability to detect and separate interactions between genotypic parameters and environmental variables. Additionally, this study demonstrates the potential value of the proposed model in helping farmers achieve higher yields by optimizing seed selection.This article is published as Chang, Yanbin, Jeremy Latham, Mark Licht, and Lizhi Wang. "A data-driven crop model for maize yield prediction." Communications Biology 6, no. 1 (2023): 439.
DOI: 10.1038/s42003-023-04833-y.
Copyright 2023 The Author(s).
Attribution 4.0 International (CC BY 4.0).
Posted with permission
Evaluation of a redox-initiated in situ hydrogel as vitreous substitute
No full textCurrently there is no material clinically available as a long-term vitreous substitute. In this study, an insitu gelation system based on alpha-poly(ethylene glycol) methacrylate (alpha-PEG-MA) and a redox-initiated radical polymerization/crosslinking reaction was evaluated for this purpose. Ammonium persulfate CAPS) and N,N,N',N'-tetramethyl ethylene diamine (TMEDA) were used as initiators. The gelation time, rheological properties, reaction kinetics and swelling profiles were studied in detail and the system with 10 wt% of alpha-PEG-MA and 8 mM APS/TMEDA was chosen as the optimal material for in vivo studies. Using the rabbit as the animal model, we showed that the system did form a space-filling and transparent gel in the vitreous cavity, and the inflammation response could be controlled to an acceptable level. (C) 2014 Elsevier Ltd. All rights reserved.Polymer ScienceSCI(E)[email protected]; [email protected]; [email protected]
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