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Scaling Behavior of Peat Properties during the Holocene: A Case Study from Central European Russia. LAND 2022. [DOI: 10.3390/land11060862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A better understanding of past climate change is vital to our ability to predict possible future environmental dynamics. This study attempts to investigate the dynamic features of the temporal variability of peat humification, water table depth and air temperature by analyzing palaeoecological data from the Valdai Uplands region (Central European Russia). The regression analysis revealed the presence of a periodicity of about 6000 years in the reconstructed peat humification timeseries. Nonlinear analysis showed that humification time variability, water table depth and air temperature exhibit persistent long-range correlations of 1/f type. This indicates that a fluctuation in these variables in the past is very likely to be followed by a similar one in the future, but is magnified by 1/f power-law. In addition, it dictates that humification, water table depth and temperature are key parameters of a system that implies the existence of a special structure, such as self-organized criticality, operating close to a minimum stability configuration, and achieves it without any fine adjustment by external forcing. These conclusions point to new avenues for modeling future ecosystem disturbances and, in particular, for predicting relevant extreme events.
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Xiao S, Cai Y, Guo Y, Lin J, Liu G, Lan X, Song Y. Experimental Study on Axial Compressive Performance of Polyvinyl Alcohol Fibers Reinforced Fly Ash-Slag Geopolymer Composites. Polymers (Basel) 2021; 14:polym14010142. [PMID: 35012164 PMCID: PMC8747670 DOI: 10.3390/polym14010142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/26/2021] [Accepted: 12/29/2021] [Indexed: 01/24/2023] Open
Abstract
Geopolymer concrete (GC) has been gaining attention in research and engineering circles; however, it is a brittle material with poor tensile performance and crack resistance. To address these problems, we introduced fibers into GC. In this study, axial compression and scanning electron microscope (SEM) tests were carried out on polyvinyl alcohol (PVA) short fiber reinforced low-calcium fly ash-slag-based geopolymer concrete (PFRGC). The ratio of PVA short fibers and low-calcium fly ash on the compression behavior of fiber reinforced geopolymer concrete (FRGC) were investigated and discussed. The test results show that PVA fibers play a bridging role in the cracks of the specimen and bear the load together with the matrix, so the addition of PVA fibers delayed the crack propagation of GC under axial compression. However, with the increase of low-calcium fly ash/PVA fibers, the number of unreacted fly ash particles in PFRGCs increases. Too many unreacted fly ash particles make GC more prone to micro-cracks during loading, adversely affecting compressive properties. Therefore, the axial compressive strength, elastic modulus, and Poisson’s ratio of GC decrease with the increasing low-calcium fly ash/PVA fibers.
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Affiliation(s)
- Shuhua Xiao
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (S.X.); (Y.C.); (Y.S.)
| | - Yongjian Cai
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (S.X.); (Y.C.); (Y.S.)
| | - Yongchang Guo
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (S.X.); (Y.C.); (Y.S.)
- Correspondence: (Y.G.); (J.L.); Tel.: +86-159-1580-5955 (Y.G.); +86-137-1081-0754 (J.L.)
| | - Jiaxiang Lin
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (S.X.); (Y.C.); (Y.S.)
- Correspondence: (Y.G.); (J.L.); Tel.: +86-159-1580-5955 (Y.G.); +86-137-1081-0754 (J.L.)
| | - Guotao Liu
- Guangdong GW Metal Industry Group Co., Ltd., Guangzhou 510030, China;
| | - Xuewei Lan
- Guangzhou Zengcheng Zhengyuan Construction Engineering Testing Center Co., Ltd., Guangzhou 511300, China;
| | - Ying Song
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (S.X.); (Y.C.); (Y.S.)
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Reactive Oxygen Species Are Essential for Vasoconstriction upon Cold Exposure. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8578452. [PMID: 34868457 PMCID: PMC8635890 DOI: 10.1155/2021/8578452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 10/20/2021] [Indexed: 12/02/2022]
Abstract
Purpose We explored the role of ROS in cold-induced vasoconstriction and corresponding mechanism. Methods Three experiments were performed. First, we measured blood flow in human hands before and after cold exposure. Second, 24 mice were randomly divided into 3 groups: 8 mice received saline injection, 8 received subcutaneous Tempol injection, and 8 received intrathecal Tempol injection. After 30 min, we determined blood flow in the skin before and after cold exposure. Finally, we used Tempol, CCG-1423, and Go 6983 to pretreat HAVSMCs and HUVECs for 24 h. Then, cells in the corresponding groups were exposed to cold (6 h, 4°C). After cold exposure, the cytoskeleton was stained. Intracellular Ca2+ and ROS levels were measured by flow cytometry and fluorescence microscopy. We measured protein expression via Western blotting. Results In the first experiment, after cold exposure, maximum skin blood flow decreased to 118.4 ± 50.97 flux units. Then, Tempol or normal saline pretreatment did not change skin blood flow. Unlike intrathecal Tempol injection, subcutaneous Tempol injection increased skin blood flow after cold exposure. Finally, cold exposure for 6 h shrank the cells, making them narrower, and increased intracellular Ca2+ and ROS levels in HUVECs and HAVSMCs. Tempol reduced cell shrinkage and decreased intracellular Ca2+ levels. In addition, Tempol decreased intracellular ROS levels. Cold exposure increased RhoA, Rock1, p-MLC-2, ET-1, iNOS, and p-PKC expression and decreased eNOS expression. Tempol or CCG-1423 pretreatment decreased RhoA, Rock1, and p-MLC-2 levels in HAVSMCs. Furthermore, Tempol or Go 6983 pretreatment decreased ET-1, iNOS, and p-PKC expression and increased eNOS expression in HUVECs. Conclusion ROS mediate the vasoconstrictor response within the cold-induced vascular response, and ROS in blood vessel tissues rather than nerve fibers are involved in vasoconstriction via the ROS/RhoA/ROCK1 and ROS/PKC/ET-1 pathways in VSMCs and endothelial cells.
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Tsyganov AN, Zarov EA, Mazei YA, Kulkov MG, Babeshko KV, Yushkovets SY, Payne RJ, Ratcliffe JL, Fatyunina YA, Zazovskaya EP, Lapshina ED. Key periods of peatland development and environmental changes in the middle taiga zone of Western Siberia during the Holocene. AMBIO 2021; 50:1896-1909. [PMID: 33825155 PMCID: PMC8497661 DOI: 10.1007/s13280-021-01545-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/16/2020] [Accepted: 02/10/2021] [Indexed: 05/26/2023]
Abstract
The response of peatlands to climate change can be highly variable. Through understanding past changes we can better predict the response of peatlands to future climate change. We use a multi-proxy approach to reconstruct the surface wetness and carbon accumulation of the Mukhrino mire (Western Siberia), describing the development of the mire since peat formation in the early Holocene, around 9360 cal. year BP. The mire started as a rich fen which initiated after paludification of a spruce forest (probably in response to a wetter climate), while the Mukhrino mire progressed to ombrotrophic bog conditions (8760 cal. year BP). This transition coincided with the intensive development of mires in Western Siberia and was associated with active carbon accumulation (31 g m-2 year-1). The ecosystem underwent a change to a tree-covered state around 5860 cal. year BP, likely in response to warming and possible droughts and this accompanied low carbon accumulation (12 g m2 year-1). If the future climate will be warmer and wetter, then regional mires are likely to remain a carbon sink, alternatively, a reversion to the wooded state with reduced carbon sink strength is possible.
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Affiliation(s)
- Andrey N. Tsyganov
- Department of General Ecology and Hydrobiology, Lomonosov Moscow State University, Leninskie Gory 1, building 12, Moscow, Russia 119234
- Laboratory of Soil Zoology and General Entomology, A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninskiy prospekt 33, Moscow, Russia 119071
| | - Evgeny A. Zarov
- Research Education Center of Environmental Dynamics and Climate Change (UNESCO Chair), Yugra State University, Chekhova str. 16, Khanty-Mansiysk, Russia 628007
| | - Yuri A. Mazei
- Department of General Ecology and Hydrobiology, Lomonosov Moscow State University, Leninskie Gory 1, building 12, Moscow, Russia 119234
- Laboratory of Soil Zoology and General Entomology, A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninskiy prospekt 33, Moscow, Russia 119071
- Faculty of Biology, Shenzhen MSU-BIT University, 1 International University Park Road, Dayun New Town, Longgang District, Shenzhen, 517182 China
| | - Mikhail G. Kulkov
- Research Education Center of Environmental Dynamics and Climate Change (UNESCO Chair), Yugra State University, Chekhova str. 16, Khanty-Mansiysk, Russia 628007
- Research and Analytical Centre for the Rational Use of the Subsoil named after V.I.Shpilman, Studencheskaya str. 2, Khanty-Mansiysk, Russia 628007
| | - Kirill V. Babeshko
- Department of General Biology and Biochemistry, Penza State University, Lermontova str. 37, building 15, Penza, Russia 440026
- Department of Zoology and Ecology, Penza State University, Lermontova str. 37, building 15, Penza, Russia 440026
| | - Svetlana Y. Yushkovets
- Department of Zoology and Ecology, Penza State University, Lermontova str. 37, building 15, Penza, Russia 440026
| | | | - Joshua L. Ratcliffe
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Yulia A. Fatyunina
- Department of General Biology and Biochemistry, Penza State University, Lermontova str. 37, building 15, Penza, Russia 440026
| | - Elya P. Zazovskaya
- Laboratory of Radiocarbon Dating and Electron Microscopy, Institute of Geography of the Russian Academy of Science (IG RAS), Staromonetniy Lane 29, Moscow, Russia 119017
| | - Elena D. Lapshina
- Research Education Center of Environmental Dynamics and Climate Change (UNESCO Chair), Yugra State University, Chekhova str. 16, Khanty-Mansiysk, Russia 628007
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Varotsos CA, Mazei Y, Saldaev D, Efstathiou M, Voronova T, Xue Y. Nowcasting of air pollution episodes in megacities: A case study for Athens, Greece. ATMOSPHERIC POLLUTION RESEARCH 2021; 12:101099. [DOI: 10.1016/j.apr.2021.101099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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Wu W, Chen B, Wu G, Wan Y, Zhou Q, Zhang H, Zhang J. Increased susceptibility to temperature variation for non-accidental emergency ambulance dispatches in Shenzhen, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:32046-32056. [PMID: 33624238 DOI: 10.1007/s11356-021-12942-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Most studies focused on the temporal trend of mortality risk associated with temperature exposure. The relative role of heat, cold, and temperature variation (TV) on morbidity and its temporal trends are explored insufficiently. This study aims to investigate the temporal trends of emergency ambulance dispatch (EAD) risk and the attributable burden of heat, cold, and hourly temperature variation (HTV). We collected time-series data of daily EAD and ambient temperature in Shenzhen from 2010 to 2017. HTV was calculated as the standard deviation of the hourly temperatures between 2 consecutive days. Quasi-Poisson generalized additive models (GAM) with a time-varying distributed lag nonlinear model (DLNM) were applied to examine temporal trends of the HTV-, heat-, and cold-EAD association. The temporal variation of the attributable fraction (AF%) and attributable number (AN) for different temperature exposures was also calculated. The largest RR was observed in extreme cold [1.30 (95% CI: 1.18, 1.43)] and moderate cold [1.25 (95% CI: 1.17, 1.34)]. Significant increasing trends in HTV-related effects and burden were observed, especially for the extreme HTV effects (P for interaction < 0.05). Decreasing trends were observed in the heat-related effect and burden, though it showed no significance (P for interaction = 0.46). There was no clear change pattern of cold-related effects and burdens. Overall, the three temperature exposure caused 13.7% of EAD, of which 4.1%, 4.3%, and 5.3% were attributed to HTV, heat, and cold, respectively. All the temperature indexes in this study, especially the cold effect, are responsible for the increased risk of EAD. People have become more susceptible to HTV over the recent decade. However, there is no clear evidence to support the temporal change of the population's susceptibility to heat and cold. Thus, in addition to heat and cold, the emergency ambulance service department should pay more attention to HTV under climate change.
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Affiliation(s)
- Wenjing Wu
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No.16 Section 3, Renmin South Road, Chengdu, 610044, China
| | - Bo Chen
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No.16 Section 3, Renmin South Road, Chengdu, 610044, China
| | - Gonghua Wu
- Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, Guangdong, China
| | - Yunying Wan
- Shenzhen Emergency Medical Center, Shenzhen, 518035, China
| | - Qiang Zhou
- Shenzhen Emergency Medical Center, Shenzhen, 518035, China
| | - Hua Zhang
- Shenzhen Emergency Medical Center, Shenzhen, 518035, China
| | - Juying Zhang
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No.16 Section 3, Renmin South Road, Chengdu, 610044, China.
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Varotsos C, Krapivin V, Mkrtchyan F, Zhou X. On the effects of aviation on carbon-methane cycles and climate change during the period 2015-2100. ATMOSPHERIC POLLUTION RESEARCH 2021; 12:184-194. [DOI: 10.1016/j.apr.2020.08.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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Abstract
Atmospheric pollutants and environmental indicators are often used to reconstruct historic atmospheric pollution from peat, as it accumulates over time by decomposing plant material, thus recording a history of air pollution. In the present study, three key parameters related to the peat bogs’ surface wetness dynamics in European Russia during the Holocene were investigated using modern statistical analysis. These parameters are: (i) the water table depth (WTD) in relation to the surface, which is reconstructed based on the community structure of the subfossil testate amoeba assemblages; (ii) the peat humification estimated as absorption of alkaline extract that directly reflects moisture at which the peat was formed; (iii) the Climate Moisture Index (CMI) and the Aridity Index derived from pollen-based reconstructions of the mean annual temperature and precipitation and classifying moisture conditions as the ratio between available annual precipitation and potential land surface evapotranspiration. All these parameters provide useful information about the paleoclimate (atmospheric moisture component) dynamics. High values of WTD and peat humification appear to comply with Gutenberg–Richter law. It is noteworthy that this law also seems to reproduce the high values of the modeled climate moisture and aridity indices. The validity of this new result is checked by replacing “conventional time” with “natural time”. On this basis, a new nowcasting tool is developed to more accurately estimate the average waiting time for the extreme values of these climate parameters. This will help to understand climate variability better to address emerging development needs and priorities by implementing empirical studies of the interactions between climatic effects, mitigation, adaptation, and sustainable growth.
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Varotsos CA, Krapivin VF, Mkrtchyan FA. On the Recovery of the Water Balance. WATER, AIR, & SOIL POLLUTION 2020; 231:170. [DOI: 10.1007/s11270-020-04554-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/26/2020] [Indexed: 06/16/2023]
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