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Showing papers by "Ocean University of China published in 2020"


Journal ArticleDOI
TL;DR: In this article, the authors reported productive infection of SARS-CoV-2 in ACE2+ mature enterocytes in human small intestinal enteroids, which may contribute to local and systemic illness and overall disease progression.
Abstract: Gastrointestinal symptoms and fecal shedding of SARS-CoV-2 RNA are frequently observed in COVID-19 patients. However, it is unclear whether SARS-CoV-2 replicates in the human intestine and contributes to possible fecal-oral transmission. Here, we report productive infection of SARS-CoV-2 in ACE2+ mature enterocytes in human small intestinal enteroids. Expression of two mucosa-specific serine proteases, TMPRSS2 and TMPRSS4, facilitated SARS-CoV-2 spike fusogenic activity and promoted virus entry into host cells. We also demonstrate that viruses released into the intestinal lumen were inactivated by simulated human colonic fluid, and infectious virus was not recovered from the stool specimens of COVID-19 patients. Our results highlight the intestine as a potential site of SARS-CoV-2 replication, which may contribute to local and systemic illness and overall disease progression.

778 citations


Journal ArticleDOI
08 Oct 2020-Nature
TL;DR: A global N2O inventory is presented that incorporates both natural and anthropogenic sources and accounts for the interaction between nitrogen additions and the biochemical processes that control N 2O emissions, using bottom-up, top-down and process-based model approaches.
Abstract: Nitrous oxide (N2O), like carbon dioxide, is a long-lived greenhouse gas that accumulates in the atmosphere. Over the past 150 years, increasing atmospheric N2O concentrations have contributed to stratospheric ozone depletion1 and climate change2, with the current rate of increase estimated at 2 per cent per decade. Existing national inventories do not provide a full picture of N2O emissions, owing to their omission of natural sources and limitations in methodology for attributing anthropogenic sources. Here we present a global N2O inventory that incorporates both natural and anthropogenic sources and accounts for the interaction between nitrogen additions and the biochemical processes that control N2O emissions. We use bottom-up (inventory, statistical extrapolation of flux measurements, process-based land and ocean modelling) and top-down (atmospheric inversion) approaches to provide a comprehensive quantification of global N2O sources and sinks resulting from 21 natural and human sectors between 1980 and 2016. Global N2O emissions were 17.0 (minimum-maximum estimates: 12.2-23.5) teragrams of nitrogen per year (bottom-up) and 16.9 (15.9-17.7) teragrams of nitrogen per year (top-down) between 2007 and 2016. Global human-induced emissions, which are dominated by nitrogen additions to croplands, increased by 30% over the past four decades to 7.3 (4.2-11.4) teragrams of nitrogen per year. This increase was mainly responsible for the growth in the atmospheric burden. Our findings point to growing N2O emissions in emerging economies-particularly Brazil, China and India. Analysis of process-based model estimates reveals an emerging N2O-climate feedback resulting from interactions between nitrogen additions and climate change. The recent growth in N2O emissions exceeds some of the highest projected emission scenarios3,4, underscoring the urgency to mitigate N2O emissions.

650 citations


Journal ArticleDOI
TL;DR: This review introduces the progress of research on AMPs comprehensively and systematically, including their classification, mechanism of action, design methods, environmental factors affecting their activity, application status, prospects in various fields and problems to be solved.
Abstract: Antimicrobial peptides (AMPs) are a class of small peptides that widely exist in nature and they are an important part of the innate immune system of different organisms. AMPs have a wide range of inhibitory effects against bacteria, fungi, parasites and viruses. The emergence of antibiotic-resistant microorganisms and the increasing of concerns about the use of antibiotics resulted in the development of AMPs, which have a good application prospect in medicine, food, animal husbandry, agriculture and aquaculture. This review introduces the progress of research on AMPs comprehensively and systematically, including their classification, mechanism of action, design methods, environmental factors affecting their activity, application status, prospects in various fields and problems to be solved. The research progress on antivirus peptides, especially anti-coronavirus (COVID-19) peptides, has been introduced given the COVID-19 pandemic worldwide in 2020.

469 citations


Journal ArticleDOI
10 Apr 2020
TL;DR: In this paper, the authors synthesize the understanding of ENSO teleconnections to South America, focusing on the mechanisms and diversity of resulting Teleconnections, and outline the impacts of the El Nino-Southern Oscillation on South America. But, while the understanding has improved, with implications for prediction and projection, uncertainty remains in regards to the robustness of the impacts, interbasin climate interactions and interplay with greenhouse warming.
Abstract: The climate of South America (SA) has long held an intimate connection with El Nino, historically describing anomalously warm sea-surface temperatures off the coastline of Peru. Indeed, throughout SA, precipitation and temperature exhibit a substantial, yet regionally diverse, relationship with the El Nino–Southern Oscillation (ENSO). For example, El Nino is typically accompanied by drought in the Amazon and north-eastern SA, but flooding in the tropical west coast and south-eastern SA, with marked socio-economic effects. In this Review, we synthesize the understanding of ENSO teleconnections to SA. Recent efforts have sought improved understanding of ocean–atmosphere processes that govern the impact, inter-event and decadal variability, and responses to anthropogenic warming. ENSO’s impacts have been found to vary markedly, affected not only by ENSO diversity, but also by modes of variability within and outside of the Pacific. However, while the understanding of ENSO–SA relationships has improved, with implications for prediction and projection, uncertainty remains in regards to the robustness of the impacts, inter-basin climate interactions and interplay with greenhouse warming. A coordinated international effort is, therefore, needed to close the observational, theoretical and modelling gaps currently limiting progress, with specific efforts in extending palaeoclimate proxies further back in time, reducing systematic model errors and improving simulations of ENSO diversity and teleconnections. The El Nino–Southern Oscillation exerts a strong influence on the global climate, including South America, where understanding of the phenomenon first emerged. This Review outlines the impacts of the El Nino–Southern Oscillation on South America, focusing on the mechanisms and diversity of resulting teleconnections.

256 citations


Journal ArticleDOI
Sergei Põlme1, Sergei Põlme2, Kessy Abarenkov1, R. Henrik Nilsson3, Björn D. Lindahl4, Karina E. Clemmensen4, Håvard Kauserud5, Nhu H. Nguyen6, Rasmus Kjøller7, Scott T. Bates8, Petr Baldrian9, Tobias Guldberg Frøslev7, Kristjan Adojaan2, Alfredo Vizzini10, Ave Suija2, Donald H. Pfister11, Hans Otto Baral, Helle Järv12, Hugo Madrid13, Hugo Madrid14, Jenni Nordén, Jian-Kui Liu15, Julia Pawłowska16, Kadri Põldmaa2, Kadri Pärtel2, Kadri Runnel2, Karen Hansen17, Karl-Henrik Larsson, Kevin D. Hyde18, Marcelo Sandoval-Denis, Matthew E. Smith19, Merje Toome-Heller20, Nalin N. Wijayawardene, Nelson Menolli21, Nicole K. Reynolds19, Rein Drenkhan22, Sajeewa S. N. Maharachchikumbura15, Tatiana Baptista Gibertoni23, Thomas Læssøe7, William J. Davis24, Yuri Tokarev, Adriana Corrales25, Adriene Mayra Soares, Ahto Agan2, A. R. Machado23, Andrés Argüelles-Moyao26, Andrew P. Detheridge, Angelina de Meiras-Ottoni23, Annemieke Verbeken27, Arun Kumar Dutta28, Bao-Kai Cui29, C. K. Pradeep, César Marín30, Daniel E. Stanton, Daniyal Gohar2, Dhanushka N. Wanasinghe31, Eveli Otsing2, Farzad Aslani2, Gareth W. Griffith, Thorsten Lumbsch32, Hans-Peter Grossart33, Hans-Peter Grossart34, Hossein Masigol35, Ina Timling36, Inga Hiiesalu2, Jane Oja2, John Y. Kupagme2, József Geml, Julieta Alvarez-Manjarrez26, Kai Ilves2, Kaire Loit22, Kalev Adamson22, Kazuhide Nara37, Kati Küngas2, Keilor Rojas-Jimenez38, Krišs Bitenieks39, Laszlo Irinyi40, Laszlo Irinyi41, Laszlo Nagy, Liina Soonvald22, Li-Wei Zhou31, Lysett Wagner34, M. Catherine Aime8, Maarja Öpik2, María Isabel Mujica30, Martin Metsoja2, Martin Ryberg42, Martti Vasar2, Masao Murata37, Matthew P. Nelsen32, Michelle Cleary4, Milan C. Samarakoon18, Mingkwan Doilom31, Mohammad Bahram4, Mohammad Bahram2, Niloufar Hagh-Doust2, Olesya Dulya2, Peter R. Johnston43, Petr Kohout9, Qian Chen31, Qing Tian18, Rajasree Nandi44, Rasekh Amiri2, Rekhani H. Perera18, Renata dos Santos Chikowski23, Renato Lucio Mendes-Alvarenga23, Roberto Garibay-Orijel26, Robin Gielen2, Rungtiwa Phookamsak31, Ruvishika S. Jayawardena18, Saleh Rahimlou2, Samantha C. Karunarathna31, Saowaluck Tibpromma31, Shawn P. Brown45, Siim-Kaarel Sepp2, Sunil Mundra5, Sunil Mundra46, Zhu Hua Luo47, Tanay Bose48, Tanel Vahter2, Tarquin Netherway4, Teng Yang31, Tom W. May49, Torda Varga, Wei Li50, Victor R. M. Coimbra23, Virton Rodrigo Targino de Oliveira23, Vitor Xavier de Lima23, Vladimir S. Mikryukov2, Yong-Zhong Lu51, Yosuke Matsuda52, Yumiko Miyamoto53, Urmas Kõljalg1, Urmas Kõljalg2, Leho Tedersoo1, Leho Tedersoo2 
American Museum of Natural History1, University of Tartu2, University of Gothenburg3, Swedish University of Agricultural Sciences4, University of Oslo5, University of Hawaii at Manoa6, University of Copenhagen7, Purdue University8, Academy of Sciences of the Czech Republic9, University of Turin10, Harvard University11, Synlab Group12, Universidad Mayor13, Universidad Santo Tomás14, University of Electronic Science and Technology of China15, University of Warsaw16, Swedish Museum of Natural History17, Mae Fah Luang University18, University of Florida19, Laos Ministry of Agriculture and Forestry20, São Paulo Federal Institute of Education, Science and Technology21, Estonian University of Life Sciences22, Federal University of Pernambuco23, United States Department of Energy24, Del Rosario University25, National Autonomous University of Mexico26, Ghent University27, West Bengal State University28, Beijing Forestry University29, Pontifical Catholic University of Chile30, Chinese Academy of Sciences31, Field Museum of Natural History32, University of Potsdam33, Leibniz Association34, University of Gilan35, University of Alaska Fairbanks36, University of Tokyo37, University of Costa Rica38, Forest Research Institute39, University of Sydney40, Westmead Hospital41, Uppsala University42, Landcare Research43, University of Chittagong44, University of Memphis45, United Arab Emirates University46, Ministry of Land and Resources of the People's Republic of China47, University of Pretoria48, Royal Botanic Gardens49, Ocean University of China50, Guizhou University51, Mie University52, Hokkaido University53
TL;DR: Fungal traits and character database FungalTraits operating at genus and species hypothesis levels is presented in this article, which includes 17 lifestyle related traits of fungal and Stramenopila genera.
Abstract: The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies. Over the past decades, rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats. Yet, in spite of the progress of molecular methods, knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging. In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels. Combining the information from previous efforts such as FUNGuild and Fun(Fun) together with involvement of expert knowledge, we reannotated 10,210 and 151 fungal and Stramenopila genera, respectively. This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera, designed for rapid functional assignments of environmental studies. In order to assign the trait states to fungal species hypotheses, the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences. On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1% dissimilarity threshold.

245 citations


Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper analyzed the effect of environmental regulation and R&D tax incentives on green product innovation from a disciplinary and incentive perspective, and showed a U-shaped relationship between environmental regulations and green product innovations.

239 citations


Journal ArticleDOI
TL;DR: This review paper overviews the progress of BCP-templated mesoporous materials over the past 10 years, with an emphasis on the discussions of synthetic methodologies, the control of materials structures (including morphology and pore size/shape), and potential applications particularly in rechargeable batteries, supercapacitors, electro-/photocatalysis, solar cells, etc.
Abstract: Self-assembly of block copolymers (BCPs) provides a versatile strategy for controllable preparation of a broad range of functional materials with different ordered structures. In recent decades, this soft-templating strategy has been widely utilized for preparing a wide range of mesoporous materials. These porous materials have attracted tremendous interest in energy storage and conversion (ESC) applications in view of their ability to absorb, store, and interact with guest species on their exterior/interior surfaces and in the pore space. Compared with other synthetic approaches, such as template-free and hard-templating methods, BCP soft-templating protocols show great advantages in the construction of large mesopores with diameters between 10-60 nm, which are suitable for applications requiring the storage or hosting of large-sized species/molecules. In addition, this strategy shows incomparable merits in the flexible control of pore size/architecture/wall thickness, which determines the final performance of mesoporous materials in ESC devices. In the last decade, rapid development has been witnessed in the area of BCP-templated mesoporous materials. In this review paper, we overview the progress of this field over the past 10 years, with an emphasis on the discussions of synthetic methodologies, the control of materials structures (including morphology and pore size/shape), and potential applications particularly in rechargeable batteries, supercapacitors, electro-/photocatalysis, solar cells, etc.

231 citations


Journal ArticleDOI
TL;DR: Combined sulfur and nitrogen (S−−12.9% and N−−9% )-rich carbons are synthesized for potassium ion anode applications.

201 citations


Journal ArticleDOI
TL;DR: An anticoagulation agent dipyridamole (DIP) in silico, which suppressed SARS-CoV-2 replication in vitro, was identified and associated with significantly decreased concentrations of D-dimers, increased lymphocyte and platelet recovery in the circulation, and markedly improved clinical outcomes in comparison to the control patients.

196 citations


Journal ArticleDOI
TL;DR: The preparation, physicochemical properties, chemical and physical modification methods of chitosan, which could help to understand its biological activities and applications, and some insights into its future potential are provided.

188 citations


Journal ArticleDOI
TL;DR: In vitro and in vivo investigations demonstrate that the hydrogel has enhanced antibacterial and anti‐inflammatory capabilities and can significantly accelerate skin tissue regeneration and wound closure.

Journal ArticleDOI
TL;DR: This article proposes a novel selection mechanism augmenting the generic DE algorithm (NSODE) to achieve better optimization results and shows that the NSODE can obtain superior feasible solutions compared with solutions produced by several algorithms reported in the literature.
Abstract: The emergence of fuzzy sets makes job-shop scheduling problem (JSSP) become better aligned with the reality. This article addresses the JSSP with fuzzy execution time and fuzzy completion time (FJSSP). We choose the classic differential evolution (DE) algorithm as the basic optimization framework. The advantage of the DE algorithm is that it uses a special evolutionary strategy of difference vector sets to carry out mutation operation. However, DE is not very effective in solving some instances of FJSSP. Therefore, we propose a novel selection mechanism augmenting the generic DE algorithm (NSODE) to achieve better optimization results. The proposed selection operator adopted in this article aims at a temporary retention of all children generated by the parent generation, and then selecting N better solutions as the new individuals from N parents and N children. Various examples of fuzzy shop scheduling problems are experimented with to test the performance of the improved DE algorithm. The NSODE algorithm is compared with a variety of existing algorithms such as ant colony optimization, particle swarm optimization, and cuckoo search. Experimental results show that the NSODE can obtain superior feasible solutions compared with solutions produced by several algorithms reported in the literature.

Journal ArticleDOI
TL;DR: In this review, the recent approaches in the chemical and physical preparation and the application of alginate hydrogels in wound dressings are summarized.

Journal ArticleDOI
TL;DR: The five site selection stages, criteria selection, data normalization, criteria weighting, alternative evaluation and result validation, are revealed by content analysis and it is found that different energy sources emphasize different criteria; however, some similarities exist.

Journal ArticleDOI
TL;DR: A fuzzy sliding-mode controller is developed to realize reachability of a predefined switching surface and desirable sliding motion and sufficient conditions for stochastic stability of the obtained sliding mode dynamics is developed in the sense of generally uncertain transition rates.
Abstract: This paper is focused on the event-triggered fuzzy sliding-mode control of networked control systems regulated by semi-Markov process. First, through movement-decomposition method, the networked control system is transformed into two lower-order subsystems. Then, an event-triggered scheme based on a delay system model approach is proposed in designing the switching surface and obtaining the sliding mode dynamics. Furthermore, a fuzzy sliding-mode controller is developed to realize reachability of a predefined switching surface and desirable sliding motion. Moreover, in terms of linear matrix inequality method, sufficient conditions for stochastic stability of the obtained sliding mode dynamics is developed in the sense of generally uncertain transition rates. Finally, the applicability of the proposed results are verified numerically on the single-link robot arm system.

Journal ArticleDOI
TL;DR: The approach is to harness the germline-encoded interferon antiviral response to inhibit SARS-CoV-2 replication thereby limiting its pathogenicity and providing the molecular basis for its therapeutic development.
Abstract: Cholesterol 25-hydroxylase (CH25H) is an interferon (IFN)-stimulated gene that shows broad antiviral activities against a wide range of enveloped viruses. Here, using an IFN-stimulated gene screen against vesicular stomatitis virus (VSV)-SARS-CoV and VSV-SARS-CoV-2 chimeric viruses, we identified CH25H and its enzymatic product 25-hydroxycholesterol (25HC) as potent inhibitors of SARS-CoV-2 replication. Internalized 25HC accumulates in the late endosomes and potentially restricts SARS-CoV-2 spike protein catalyzed membrane fusion via blockade of cholesterol export. Our results highlight one of the possible antiviral mechanisms of 25HC and provide the molecular basis for its therapeutic development.

Journal ArticleDOI
TL;DR: In this paper, nanoparticles have been dispersed into paraffin in order to enhance the thermal conductivity of the inner duct, which leads to a reduction in the discharging time of PCM through solidification to reduce.

Journal ArticleDOI
TL;DR: It has been demonstrated that a new virtual screening approach with accelerated free energy perturbation-based absolute binding free energy (FEP-ABFE) predictions can reach an unprecedentedly high hit rate, leading to successful identification of 15 potent inhibitors of SARS-CoV-2 main protease (Mpro) from 25 computationally selected drugs under a threshold of Ki = 4 μM.
Abstract: The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global crisis. There is no therapeutic treatment specific for COVID-19. It is highly desirable to identify potential antiviral agents against SARS-CoV-2 from existing drugs available for other diseases and thus repurpose them for treatment of COVID-19. In general, a drug repurposing effort for treatment of a new disease, such as COVID-19, usually starts from a virtual screening of existing drugs, followed by experimental validation, but the actual hit rate is generally rather low with traditional computational methods. Here we report a virtual screening approach with accelerated free energy perturbation-based absolute binding free energy (FEP-ABFE) predictions and its use in identifying drugs targeting SARS-CoV-2 main protease (Mpro). The accurate FEP-ABFE predictions were based on the use of a restraint energy distribution (RED) function, making the practical FEP-ABFE-based virtual screening of the existing drug library possible. As a result, out of 25 drugs predicted, 15 were confirmed as potent inhibitors of SARS-CoV-2 Mpro The most potent one is dipyridamole (inhibitory constant Ki = 0.04 µM) which has shown promising therapeutic effects in subsequently conducted clinical studies for treatment of patients with COVID-19. Additionally, hydroxychloroquine (Ki = 0.36 µM) and chloroquine (Ki = 0.56 µM) were also found to potently inhibit SARS-CoV-2 Mpro We anticipate that the FEP-ABFE prediction-based virtual screening approach will be useful in many other drug repurposing or discovery efforts.

Journal ArticleDOI
TL;DR: In this article, a bilayer composite consisting of a pure polyetherimide layer and a BaTiO3/P(VDF-HFP) composite layer was designed to achieve ultrahigh discharge efficiencies under external electric fields up to 400 kV mm−1.
Abstract: Polymer dielectric composites are of great interest as film capacitors that are widely used in pulsed power systems. For a long time, huge efforts have been devoted to achieving energy densities as high as possible to satisfy the miniaturization and high integration of electronic devices. However, the discharge efficiency which is particularly crucial to practical applications has gained little attention. With the target of achieving concurrently improved energy density and efficiency, a class of rationally designed bilayer composites consisting of a pure polyetherimide layer and a BaTiO3/P(VDF-HFP) composite layer were prepared. Interestingly, the bilayer composites exhibit ultrahigh discharge efficiencies η (>95%) under external electric fields up to 400 kV mm−1 which are much higher than most of the so far reported results (η < 80%). Meanwhile, a low loss (tan δ < 0.05 @ 10 kHz) comparable to that of the pure polyetherimide is obtained. In addition, the bilayer composites show impressive improvements in breakdown strengths Eb, i.e., 285%, 363%, 366% and 567% for composites with 5 vol%, 10 vol%, 20 vol% and 40 vol% BaTiO3, compared to their single layer counterparts, resulting in obviously improved energy densities Ud. In particular, the bilayer composite with 10 vol% BaTiO3 displays the most prominent comprehensive energy storage performance, i.e., η ∼ 96.8% @ 450 kV mm−1, Ud ∼ 6 J cm−3 @ 450 kV mm−1, tan δ ∼ 0.025 @ 10 kHz, and Eb ∼ 483.18 kV mm−1. The ultrahigh discharge efficiencies and high energy densities, along with low loss and breakdown strengths, make these bilayer composites ideal candidates for high-performance dielectric energy-storage capacitors.

Journal ArticleDOI
TL;DR: Enhanced versions of the NSGA-III algorithm are proposed through introducing the concept of Stud and designing several improved crossover operators of SBX, UC, and SI, and experimental results indicate that the NS GA-III methods with UC and UC-Stud (UCS) outperform the other developed variants.

OtherDOI
TL;DR: In this paper, the spatial and temporal asymmetry of El Niño and La Niña has been investigated and the importance of nonlinear dynamics and/or stochastic forcing has been discussed.
Abstract: The El Niño Southern Oscillation (ENSO) is characterized by being irregular or nonperiodic and asymmetric between El Niño and La Niña with respect to amplitude, pattern, and temporal evolution. These observed features suggest the importance of nonlinear dynamics and/or stochastic forcing. Both nonlinear deterministic chaos and linear dynamics subject to stochastic forcing and/or to non‐normal growth were introduced to explain the irregularity of ENSO, but no consensus has been reached to date given the short observational record. As a dominant source of stochastic forcing, westerly wind bursts play a role in triggering, amplifying, and determining the irregularity and asymmetry of ENSO, which are best treated as part of the deterministic dynamics or as a multiplicative noise forcing. Various nonlinear processes are responsible for the spatial and temporal asymmetry of El Niño and La Niña, which includes nonlinear ocean advection, nonlinear atmosphere‐ocean coupling, state‐dependent stochastic noise, tropical instability waves, and biophysical processes. In addition to the internal nonlinear processes, a capacitor effect of the Indian and Atlantic Oceans and atmospheric and oceanic teleconnections from extratropical Pacific could also contribute to the temporal and amplitude asymmetry of ENSO. Despite significant progress, most state‐of‐the‐art models are still lacking in simulation of the spatial and temporal asymmetry of ENSO. 1 Department of Atmospheric Sciences, Yonsei University, Seoul, Republic of Korea 2 Department of Earth and Planetary Sciences and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA 3 Institute for Geophysics, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA 4 Department of Atmospheric Sciences/IPRC, University of Hawai’i at Ma ̄noa, Honolulu, HI, USA 154 EL NIÑO SOUTHERN OSCILLATION IN A CHANGING CLIMATE determine an atmosphere‐ocean coupled stability for ENSO system (T. Li, 1997b; An & Jin, 2000; Fedorov & Philander, 2000), and for example, depending on the coupling strength, ENSO system becomes a self‐sustained and possibly chaotic oscillator under a strong coupling and a damped oscillator under a weak coupling (An & Jin, 2001). It has been suggested that some decades may be characterized by a self‐sustained, possibly chaotic dynamics, while others show a damped ENSO cycle, excited by stochastic variability (Kirtman & Schopf, 1998). However, a bifurcation between stable and unstable regimes tends to be ambiguous in the presence of noise (e.g., Levine & Jin, 2010). Westerly wind bursts (WWBs) are episodic reversals of the equatorial trade winds with a strength of 5 to 7 ms–1, zonal extent of 20–40 degrees, duration of 5–30 days, and frequency of around 5 to 10 times per year (Harrison & Vecchi, 1997; L. Yu et al., 2003; Seiki & Takayabu, 2007a). These events, a dominant source of stochastic forcing, play a role in triggering, amplifying, and even determining the spatial pattern of ENSO events (Harrison & Vecchi, 1997; Eisenman et al., 2005; Levine & Jin, 2010; Rong et al., 2011; D. Chen et al., 2015; Hayashi & Watanabe, 2017). WWBs were initially considered as additive stochastic forcing (e.g. Moore & Kleeman, 1999), yet it became clear that they depend on the background SST and tend to occur more frequently during a developing El Niño (Verbickas, 1998; L. Yu et al., 2003; Eisenman et al., 2005). These events are thus best treated as part of the deterministic dynamics or as a state‐dependent multiplicative noise forcing, with important implications to amplitude and predictability of El Niño events. El Niño is not a simple mirror image of its opposite phase, La Niña. El Niño’s amplitude is on average greater than that of La Niña (Deser & Wallace, 1987; Burgers & tephenson, 1999; An & Jin, 2004). El Niño is often followed by a La Niña in the following year, but the opposite is much less common (Larkin & Harrison, 2002; M. Chen et al., 2016; An & Kim, 2017). After their mature phase, many La Niñas persist through the following year, but most of El Niños tend to decay rapidly by next summer (Ohba & Ueda, 2007; Okumura & Deser, 2010; Choi et al. 2013; DiNezio & Deser, 2014; An & Kim, 2018). Strong El Niños are mainly loaded over the eastern Pacific with focusing toward the equator, whereas strong La Niñas are mostly loaded over the central Pacific with a wider latitudinal extension (Hoerling et al., 1997; Kang & Kug, 2002; Takahashi et al., 2011; Dommenget et al., 2013). Such amplitude/duration/transition/pattern asymmetries between El Niño and La Niña may not be surprising given the nonlinear internal dynamics and/or selective external impacts (e.g., An & Kim, 2018). Asymmetrical internal nonlinear processes that are responsible for amplitude asymmetry include the vertical ocean temperature profile (Zebiak & Cane, 1986), ocean nonlinear advection (An & Jin, 2004; Su et al. 2010), asymmetric equatorial wind response to SST (Kang & Kug, 2002; Frauen & Dommenget, 2010; Choi et al., 2013), ocean wave response to the wind stress (An & Kim, 2017, 2018), outcropping thermocline nonlinearity (Battisti & Hirst, 1989; Galanti et al., 2002; An & Jin, 2004), state‐dependent stochastic forcing (Jin et al., 2007; Kug et al., 2008; Rong et al., 2011; Levine et al., 2016; Hayashi & Watanabe, 2017), tropical instability wave activity (J. Yu & Liu, 2003; An, 2008a, 2008b), biophysical feedback (Timmermann & Jin, 2002), shortwave feedback (Lloyd et al., 2012), etc. Transition/duration asymmetry has been attributed to a selective capacitor effect of the Indian and Atlantic oceans (Ohba & Ueda, 2007; Okumura & Deser, 2010; An & Kim, 2018), development of subtropical western Pacific atmospheric circulation during decaying phase of ENSO to boost ENSO transition (B. Wang et al., 1999; B. Wang et al., 2001; Y. Li et al., 2007; B. Wu et al., 2010a), and some of aforementioned internal nonlinear processes (Choi et al., 2013; Im et al., 2015; M. Chen et al., 2016; An & Kim, 2017, 2018; M. Chen & Li, 2018). This chapter focuses on the irregularity of ENSO and on its amplitude and evolution asymmetries. In section 7.2, the origin of irregularity will be addressed together with the role of westerly wind burst events. Mechanisms for amplitude asymmetry will be discussed in section 7.3. The cause of evolution asymmetry will be reviewed in section 7.4, and we include conclusion and discussion in section 7.5.

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TL;DR: PD-PS had the highest growth inhibition and lipidosis-driven hepatic lesions of grouper, followed by P-PS and C-PS, which was mainly explained by increased hepatic bioaccumulation of MPs/NPs and released endogenous toxicants.
Abstract: Microplastics (MPs) have caused increasing global concerns due to their detrimental effects on marine ecosystems. However, the role of photodegradation in altering toxicity of MPs to marine organisms is poorly understood. We therefore investigated the photolytic transformation of pristine polystyrene fragments (P-PS) by 60-day ultraviolet (UV) irradiation, and compared the toxicity of P-PS, photodegraded PS (PD-PS), and commercially available polystyrene microbeads (C-PS) to juvenile grouper (Epinephelus moara). Photodegradation reduced the size from ∼55.9 μm of P-PS to ∼38.6 μm of PD-PS, even produced nanoparticles (∼75 nm) with a yield of 7.03 ± 0.37% (w/w), and induced surface oxidation and formation of persistent free radicals (e.g., CO•, COO•). Also, endogenous pollutants (chemical additives and polymer fragments) were leached out. Thus, PD-PS had the highest growth inhibition and lipidosis-driven hepatic lesions of grouper, followed by P-PS and C-PS, which was mainly explained by increased hepatic bioaccumulation of MPs/NPs and released endogenous toxicants. Furthermore, oxidative stress-triggered mitochondrial depolarization, suppression of fatty acid oxidation and transport, and promotion of inflammation were identified as the key mechanisms for the enhanced hepatotoxicity after photodegradation. This work provides new insight into the potential hazard and harm of MPs in marine environments after photodegradation.

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TL;DR: In this article, a review of recent advances in super-wettable materials including classification, synthesis methods and their applications is presented, and the major issues and challenges associated with the application of superwettables in the oil-water separation system are highlighted to understand better the research gap and limitations in the marketing of these materials.

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TL;DR: The results of this study illustrated that PE MPs can be a good carrier of pesticides in agricultural field and indicates the adsorption of all pesticides as spontaneous and exothermic processes.

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TL;DR: A Gram-negative bacterium isolated from marine sediments can kill and feed on Gram-positive bacteria by secreting a peptidoglycan-degrading enzyme, a new microbial interaction in the ocean.
Abstract: Predator-prey interactions play important roles in the cycling of marine organic matter. Here we show that a Gram-negative bacterium isolated from marine sediments (Pseudoalteromonas sp. strain CF6-2) can kill Gram-positive bacteria of diverse peptidoglycan (PG) chemotypes by secreting the metalloprotease pseudoalterin. Secretion of the enzyme requires a Type II secretion system. Pseudoalterin binds to the glycan strands of Gram positive bacterial PG and degrades the PG peptide chains, leading to cell death. The released nutrients, including PG-derived D-amino acids, can then be utilized by strain CF6-2 for growth. Pseudoalterin synthesis is induced by PG degradation products such as glycine and glycine-rich oligopeptides. Genes encoding putative pseudoalterin-like proteins are found in many other marine bacteria. This study reveals a new microbial interaction in the ocean.

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TL;DR: A meta-analysis will provide helpful information to elucidate the combined effect of biochar properties and soil conditions on plant growth, which is critical for developing engineered biochar with specific functionality to promote plant production and food security.


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TL;DR: In this article, Ni/TiO2/C heterogeneous composites were synthesized in one pot reaction within a short time (10min) by microwave irradiation of an aqueous mixture of nickel chloride and hexadecyltrimethylammonium bromide (CTAB) functionalized Ti3C2Tx MXene.

Journal ArticleDOI
TL;DR: The issue of observer-based adaptive sliding mode control of nonlinear Takagi–Sugeno fuzzy systems with semi-Markov switching and immeasurable premise variables is investigated and a single-link robot arm model is provided to verify the control scheme numerically.
Abstract: The issue of observer-based adaptive sliding mode control of nonlinear Takagi–Sugeno fuzzy systems with semi-Markov switching and immeasurable premise variables is investigated. More general nonlinear systems are described in the model since the selections of premise variables are the states of the system. First, a novel integral sliding surface function is proposed on the observer space, then the sliding mode dynamics and error dynamics are obtained in accordance with estimated premise variables. Second, sufficient conditions for stochastic stability with an ${H}_{\infty }$ performance disturbance attenuation level ${\gamma }$ of the sliding mode dynamics with different input matrices are obtained based on generally uncertain transition rates. Third, an observer-based adaptive controller is synthesized to ensure the finite time reachability of a predefined sliding surface. Finally, the single-link robot arm model is provided to verify the control scheme numerically.

Proceedings ArticleDOI
07 Apr 2020
TL;DR: This paper proposes the first large-scale language VAE model, Optimus, a universal latent embedding space for sentences that is first pre-trained on large text corpus, and then fine-tuned for various language generation and understanding tasks.
Abstract: When trained effectively, the Variational Autoencoder (VAE) can be both a powerful generative model and an effective representation learning framework for natural language. In this paper, we propose the first large-scale language VAE model Optimus (Organizing sentences via Pre-Trained Modeling of a Universal Space). A universal latent embedding space for sentences is first pre-trained on large text corpus, and then fine-tuned for various language generation and understanding tasks. Compared with GPT-2, Optimus enables guided language generation from an abstract level using the latent vectors. Compared with BERT, Optimus can generalize better on low-resource language understanding tasks due to the smooth latent space structure. Extensive experimental results on a wide range of language tasks demonstrate the effectiveness of Optimus. It achieves new state-of-the-art on VAE language modeling benchmarks.