An excessive westward extension of the simulated ENSO-related sea surface temperature (ENSO SST) variability in the CMIP5 and CMIP6 models is the most apparent ENSO SST pattern bias and dominates the ...intermodel spread in ENSO SST variability among the models. The ENSO SST bias lowers the models’ skill in ENSO-related simulations and induces large intermodel uncertainty in ENSO-related projections. The present study investigates the origins of the excessive westward extension of ENSO SST in 25 CMIP5 and 25 CMIP6 models. Based on the intermodel spread of ENSO SST variability simulated in the 50 models, we reveal that this ENSO SST bias among the models largely depends on the simulated cold tongue strength in the equatorial western Pacific (EWP). Models simulating a stronger cold tongue tend to simulate a larger mean zonal SST gradient in the EWP and then a larger zonal advection feedback in the EWP, favoring a more westward extension of the ENSO SST pattern. In addition, with the overall improvement in the EWP cold tongue from CMIP5 to CMIP6, the excessive westward extension bias of ENSO SST in CMIP6 models is also reduced relative to those in CMIP5 models. The results suggest that the bias and intermodel disagreement in the mean-state SST have been improved, which improves ENSO simulation.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A high throughput single-molecule method for identifying peptides and sequencing proteins based on nanopores could reduce costs and increase speeds of sequencing, allow the fabrication of portable ...home-diagnostic devices, and permit the characterization of low abundance proteins and heterogeneity in post-translational modifications. Here we engineer the size of Fragaceatoxin C (FraC) biological nanopore to allow the analysis of a wide range of peptide lengths. Ionic blockades through engineered nanopores distinguish a variety of peptides, including two peptides differing only by the substitution of alanine with glutamate. We also find that at pH 3.8 the depth of the peptide current blockades scales with the mass of the peptides irrespectively of the chemical composition of the analyte. Hence, this work shows that FraC nanopores allow direct readout of the mass of single peptide in solution, which is a crucial step towards the developing of a real-time and single-molecule protein sequencing device.
The decline of system inertia due to the increasing displacement of synchronous units by renewable units has introduced a major challenge on the frequency dynamics management of a power system. This ...paper discusses how fast-response battery energy storages can be used to maintain the frequency dynamic security. Immediately following a generation loss, the injections of batteries are adjusted instantly to ensure minimum power imbalance in the system. This control strategy is included in a novel formulation of the frequency dynamics constrained unit commitment, in which the impact of wind uncertainty is dealt with using interval-based optimization. The reformulation-linearization technique is applied to reformulate the original nonlinear model as a mixed-integer linear programming problem. Case studies on a six-bus system and the modified RTS-79 system demonstrate that the proposed method guarantees frequency security while still preserving economy without curtailing wind generation.
Boosting the resilience of power systems is one of the core requirements of smart grid. In this paper, an integrated resilience response framework is proposed, which not only links the situational ...awareness with resilience enhancement, but also provides effective and efficient responses in both preventive and emergency states. The core of the proposed framework is a two-stage robust mixed-integer optimization model, whose mathematical formulation is presented in this paper as well. To solve the above model, an algorithm based on the nested column-and-constraint generation decomposition is provided, and computational efficiency improvement techniques are proposed. Preventive response in this paper considers generator re-dispatch and topology switching, while emergency response includes generator re-dispatch, topology switching and load shedding. Several numerical simulations validate the effectiveness of the proposed framework and the efficiency of the solution methodology. Key findings include the following: 1) in terms of enhancing power grid resilience, the integrated resilience response is preferable to both independent preventive response and independent emergency response; 2) the power grid resilience could be further enhanced by utilizing topology switching in the integrated resilience response.
Since the first identification of hypoxic cells in sections of carcinomas in the 1950s, hypoxia has been known as a central hallmark of cancer cells and their microenvironment. Indeed, hypoxia ...benefits cancer cells in their growth, survival, and metastasis. The historical discovery of hypoxia‐inducible factor‐1α (HIF1A) in the early 1990s had a great influence on the field as many phenomena in hypoxia could be explained by HIF1A. However, not all regions or types of tumors are necessarily hypoxic. Thus, it is difficult to explain whole cancer pathobiology by hypoxia, especially in the early stage of cancer. Upregulation of glucose metabolism in cancer cells has been well known. Oxygen‐independent glycolysis is activated in cancer cells even in the normoxia condition, which is known as the Warburg effect. Accumulating evidence and recent advances in cancer metabolism research suggest that hypoxia‐independent mechanisms for HIF signaling activation is a hallmark for cancer. There are various mechanisms that generate pseudohypoxic conditions, even in normoxia. Given the importance of HIF1A for cancer pathobiology, the pseudohypoxia concept could shed light on the longstanding mystery of the Warburg effect and accelerate better understanding of the diverse phenomena seen in a variety of cancers.
Accumulating evidence has revealed that hypoxia‐inducible factor (HIF) signaling can be activated through a variety of hypoxia‐independent mechanisms, even in normoxia. Given the importance of HIFs for glucose metabolism and cancer pathobiology, the pseudohypoxia concept could accelerate better understanding of the diverse phenomena seen in a variety of cancers.
Biological nanopores are nanoscale sensors employed for high-throughput, low-cost, and long read-length DNA sequencing applications. The analysis and sequencing of proteins, however, is complicated ...by their folded structure and non-uniform charge. Here we show that an electro-osmotic flow through Fragaceatoxin C (FraC) nanopores can be engineered to allow the entry of polypeptides at a fixed potential regardless of the charge composition of the polypeptide. We further use the nanopore currents to discriminate peptide and protein biomarkers from 25 kDa down to 1.3 kDa including polypeptides differing by one amino acid. On the road to nanopore proteomics, our findings represent a rationale for amino-acid analysis of folded and unfolded polypeptides with nanopores.Biological nanopore-based protein sequencing and recognition is challenging due to the folded structure or non-uniform charge of peptides. Here the authors show that engineered FraC nanopores can overcome these problems and recognize biomarkers in the form of oligopeptides, polypeptides and folded proteins.
With the development of the times in recent years, people’s requirements for vision are no longer limited to the original foundation. As the core of research in this field, organic ...electroluminescence has paid great attention to the research points in the application of organic optoelectronic materials and devices in the world. From the relevant scientific research results in recent years, for example, organic light-emitting diodes can be used in flat-panel displays and solid-state lighting, organic photovoltaic cells can be used as a clean and renewable energy source to effectively alleviate the current energy needs of society, and organic storage, sensors, and so on show great promise for application. It can be seen that the research of organic optoelectronic materials and their devices will be the core hot spot of future new energy research. In the past, traditional organic optoelectronic materials are updated through the regulation strategy of covalent modification of the molecular structure. In recent years, new effective methods have been obtained to regulate the properties of excited states through physical stimulation (such as mechanical force, temperature, electric field, and magnetic field). The type of research experiment in this paper is based on the current hot smart image sensor, with the addition of organic complexes of mononuclear metal platinum and iridium metal and the organic optoelectronic device in the form of host and guest doping. The experimental results show that using PVK without energy transfer, polyvinyl carbazole (PVK) had been widely used as blue luminescent material and hole transport layer in electroluminescent device research. Simple mononuclear platinum and iridium metal complexes cannot obtain white light. For OPV devices, by selecting the correct solvent to control the bulk heterojunction, it exhibits better photovoltaic performance. Solvents play an important role in phase separation. In organic solar cells (OPV) consisting of an electron donor (D) and an acceptor (A), optimizing the D-A interface produces efficient charge separation, effectively separating excitons at the D-A interface and forming continuous electron and hole transport channels, and effective charge transport between electrodes plays a positive role.
Accumulating evidence proposed Janus-associated kinase (JAK) inhibitors as therapeutic targets warranting rapid investigation.
This study evaluated the efficacy and safety of ruxolitinib, a JAK1/2 ...inhibitor, for coronavirus disease 2019.
We conducted a prospective, multicenter, single-blind, randomized controlled phase II trial involving patients with severe coronavirus disease 2019.
Forty-three patients were randomly assigned (1:1) to receive ruxolitinib plus standard-of-care treatment (22 patients) or placebo based on standard-of-care treatment (21 patients). After exclusion of 2 patients (1 ineligible, 1 consent withdrawn) from the ruxolitinib group, 20 patients in the intervention group and 21 patients in the control group were included in the study. Treatment with ruxolitinib plus standard-of-care was not associated with significantly accelerated clinical improvement in severe patients with coronavirus disease 2019, although ruxolitinib recipients had a numerically faster clinical improvement. Eighteen (90%) patients from the ruxolitinib group showed computed tomography improvement at day 14 compared with 13 (61.9%) patients from the control group (P = .0495). Three patients in the control group died of respiratory failure, with 14.3% overall mortality at day 28; no patients died in the ruxolitinib group. Ruxolitinib was well tolerated with low toxicities and no new safety signals. Levels of 7 cytokines were significantly decreased in the ruxolitinib group in comparison to the control group.
Although no statistical difference was observed, ruxolitinib recipients had a numerically faster clinical improvement. Significant chest computed tomography improvement, a faster recovery from lymphopenia, and favorable side-effect profile in the ruxolitinib group were encouraging and informative to future trials to test efficacy of ruxolitinib in a larger population.
Application of transition metal phosphides (TMPs) for electrochemical energy conversion and storage has great potential to alleviate the energy crisis. Although there are many methods to get TMPs, it ...is still immensely challenging to fabricate hierarchical porous TMPs with superior electrochemical performances by a simple, green, and secure approach. Herein, we report a facile method to synthesize the CoP/C nanoboxes by pyrolysis of phytic acid (PA) cross-linked Co complexes that are acquired from reaction of PA and ZIF-67. The PA can not only slowly etch ZIF-67 and gain a hollow structure but also act as a source of phosphorus to prepare CoP/C nanoboxes. The CoP/C nanoboxes deliver an ultrahigh specific capacity (868 mA h g–1 at 100 mA g–1) and excellent cycle stability (523 mA h g–1 after 1000 cycles at 500 mA h g–1) when used as anode materials for lithium-ion batteries. Moreover, when used as an electrocatalyst for hydrogen evolution reaction, the CoP/C nanoboxes exhibit ultralow overpotential, small Tafel slope, and excellent durability in acidic media. The method to produce CoP/C nanoboxes is easy and environmentally friendly and can be readily extended to design other TMPs/C nanocomposites.
Conspectus It is a permanent issue for modern society to develop high-energy-density, low-cost, and safe batteries to promote technological innovation and revolutionize the human lifestyle. However, ...the current popular Li-ion batteries are approaching their ceiling in energy density, and thus other battery systems with more power need to be proposed and studied to guide this revolution. Lithium–air batteries are among the candidates for next-generation batteries because of their high energy density (3500 Wh/kg). The past 20 years have witnessed rapid developments of lithium–air batteries in electrochemistry and material engineering with scientists’ collaboration from all over the world. Despite these advances, the investigation on Li–air batteries is still in its infancy, and many bottleneck problems, including fundamental and application difficulties, are waiting to be resolved. For the electrolyte, it is prone to be attacked by intermediates (LiO2, O2 –, 1O2, O2 2–) and decomposed at high voltage, accompanying side reactions that will induce cathode passivation. For the lithium anode, it can be corroded severely by H2O and the side products, thus protection methods are urgently needed. As an integrated system, the realization of high-performance Li–air batteries requires the three components to be optimized simultaneously. In this Account, we are going to summarize our progress for optimizing Li–air batteries in the past decade, including air-electrochemistry and anode optimization. Air-electrochemistry involves the interactions among electrolytes, cathodes, and air, which is a complex issue to understand. The search for stable electrolytes is first introduced because at the early age of its development, the use of incompatible Li-ion battery electrolytes leads to some misunderstandings and troubles in the advances of Li–air batteries. After finding suitable electrolytes for Li–air batteries, the fundamental research in the reaction mechanism starts to boom, and the performance has achieved great improvement. Then, air electrode engineering is introduced to give a general design principle. Examples of carbon-based cathodes and all-metal cathodes are discussed. In addition, to understand the influence of air components on Li–air batteries, the electro-activity of N2 has been tested and the role of CO2 in Li–O2/CO2 has been refreshed. Following this, the strategies for anode optimization, including constructing artificial films, introducing hydrophobic polymer electrolytes, adding electrolyte additives, and designing alloy anodes, have been discussed. Finally, we advocate researchers in this field to conduct cell level optimizations and consider their application scenarios to promote the commercialization of Li–air batteries in the near future.
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