Two major trans‐basin mooring arrays, the Rapid Climate Change‐Meridional Overturning Circulation and Heatflux Array (RAPID) at 26.5°N since 2004 and the Overturning in the Subpolar North Atlantic ...Program (OSNAP) situated at 53°–60°N since 2014, have been continuously monitoring the Atlantic Meridional Overturning Circulation (AMOC). This study explores the connectivity of AMOC across these two mooring lines from a novel adiabatic perspective utilizing a model‐based data set. The findings unveil significant in‐phase connections facilitated by the adiabatic basinwide redistribution of water between the two lines on a monthly timescale. This adiabatic mode is a possible cause for the observed subpolar AMOC seasonality by OSNAP. Furthermore, the Labrador Sea was identified as a hotspot for adiabatic forcing of the overturning circulations, primarily attributed to its dynamic isopycnal movements.
Plain Language Summary
The Atlantic Ocean's circulation plays a crucial role in regulating Earth's climate. Two monitoring systems, Rapid Climate Change‐Meridional Overturning Circulation and Heatflux Array (RAPID) and the Subpolar North Atlantic Program (OSNAP), have been continuously observing the Atlantic Meridional Overturning Circulation (AMOC) at the mid‐ and high‐latitudes, respectively. This study explores the possibility and the extent to which the AMOC across these two sections are connected in an adiabatic manner. By analyzing data from a numerical ocean model, significant and robust connections are identified between the two MOCs when the horizontal water redistribution within the same density layer is taken into account. Based on the results, the observed seasonality of the subpolar AMOC is likely attributed to the variability of such horizontal water movement. Despite field surveys indicating lower overturning variability in the Labrador Sea compared to the eastern subpolar gyre, this study contends that the Labrador Sea holds significant importance as a primary region of adiabatic forcing that influences subpolar AMOC variability.
Key Points
An adiabatic link is identified between the overturning circulations across the two major trans‐basin mooring sections
Seasonality of the subpolar North Atlantic overturning circulation is likely caused by the adiabatic process downstream
The Labrador Sea accommodates the main forcing of the adiabatic overturning variability in the subpolar gyre region
Increasing energy demands and environment awareness have promoted extensive research on the development of alternative energy conversion and storage technologies with high efficiency and ...environmental friendliness. Among them, water splitting is very appealing, and is receiving more and more attention. The critical challenge of this renewable‐energy technology is to expedite the oxygen evolution reaction (OER) because of its slow kinetics and large overpotential. Therefore, developing efficient electrocatalysts with high catalytic activities is of great importance for high‐performance water splitting. In the past few years, much effort has been devoted to the development of alternative OER electrocatalysts based on transition‐metal elements that are low‐cost, highly efficient, and have excellent stability. Here, recent progress on the design, synthesis, and application of OER electrocatalysts based on transition‐metal elements, including Co, Ni, and Fe, is summarized, and some invigorating perspectives on the future developments are provided.
Developing efficient oxygen‐evolution electrocatalysts with high catalytic activities is of great importance for high‐performance water splitting. Recent progress in the design, synthesis, and application of OER electrocatalysts based on transition‐metal elements, including Co, Ni, and Fe, is summarized, and some invigorating perspectives on future developments are discussed.
An evidence review of face masks against COVID-19 Howard, Jeremy; Huang, Austin; Li, Zhiyuan ...
Proceedings of the National Academy of Sciences - PNAS,
01/2021, Letnik:
118, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, ...synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
Display omitted
•Aberrantly glycosylated MUC1 is expressed at high levels in most human carcinomas and certain hematologic malignancies.•MUC1-based cancer vaccines include subuint vaccines, DNA ...vaccines, viral vected vaccines, DC vaccines, and glycopeptide vaccines.•MUC1 has all the potential to be used as a target for the development of a universal cancer vaccine.
Mucin 1 (MUC1) is a transmembrane mucin glycoprotein expressed on the surface of almost all epithelial cells. Aberrantly glycosylated MUC1 is associated with cellular transformation from a normal to malignant phenotype in human cancers. Therefore, MUC1 is the major target for the design and development of cancer vaccines. MUC1-based cancer vaccines are a promising strategy for preventing cancer progression and metastasis. This review summarizes the most significant milestones achieved to date in the development of different MUC-1-based vaccine approaches in clinical trials. Further, it provides perspectives for future research that may promote clinical advances in infection-associated cancers.
Heteroarenes are important structural motif in functional molecules. A MnI‐catalyzed 1,2‐diheteroarylation of allenes via a C−H activation/Smiles rearrangement cascade is presented. The reaction ...occurred under additive‐free or even solvent‐free conditions, which allowed the creation of two C−C and one C−N bonds in a single operation. A series of structurally diverse bicyclic or tricyclic compounds bearing an exocyclic double bond were constructed in good to excellent efficiency. The decarboxylative ring‐opening of the products led to the facile synthesis of vicinal biheteroaryls. Synthetic applications were demonstrated and preliminary mechanistic studies were conducted.
Diheteroarylation of allenes: A MnI‐catalyzed C−H activation/Smiles rearrangement cascade enabled an unprecedented 1,2‐diheteroarylation of allenes. The reaction occurred under additive‐free or even solvent‐free conditions. A series of diverse bicyclic or tricyclic compounds bearing a valuable exocyclic double bond were constructed. The decarboxylative ring‐opening of the products led to the facile synthesis of vicinal biheteroaryl compounds.
Background
Coronavirus disease 2019 (COVID‐19) emerged in Wuhan city and rapidly spread globally outside China. We aimed to investigate the role of peripheral blood eosinophil (EOS) as a marker in ...the course of the virus infection to improve the efficiency of diagnosis and evaluation of COVID‐19 patients.
Methods
227 pneumonia patients who visited the fever clinics in Shanghai General Hospital and 97 hospitalized COVID‐19 patients admitted to Shanghai Public Health Clinical Center were involved in a retrospective research study. Clinical, laboratory, and radiologic data were collected. The trend of EOS level in COVID‐19 patients and comparison among patients with different severity were summarized.
Results
The majority of COVID‐19 patients (71.7%) had a decrease in circulating EOS counts, which was significantly more frequent than other types of pneumonia patients. EOS counts had good value for COVID‐19 prediction, even higher when combined with neutrophil‐to‐lymphocyte ratio. Patients with low EOS counts at admission were more likely to have fever, fatigue, and shortness of breath, with more lesions in chest CT and radiographic aggravation, and longer length of hospital stay and course of disease than those with normal EOS counts. Circulating EOS level gradually increased over the time, and was synchronous with the improvement in chest CT (12 days vs 13 days, P = .07), later than that of body temperature (12 days vs 10 days, P = .014), but earlier than that of the negative conversion of nucleic acid assays (12 days vs 17 days, P = .001).
Conclusion
Peripheral blood EOS counts may be an effective and efficient indicator in diagnosis, Evaluation, and prognosis monitoring of COVID‐19 patients.
The circulating eosinophil counts decrease dramatically in most COVID‐19 patients. Low eosinophil counts and slow recovery may be related to severe conditions. The restore of eosinophil counts is synchronous with the improvement of chest CT, later than that of body temperature, but earlier than the negative conversion of nucleic acid assays. Abbreviations: COVID‐19, coronavirus disease 2019; CT, computed tomography; EOS, eosinophil.
A novel three-dimensional (3D) hierarchical porous cobalt oxide (Co3O4) architecture was first synthesized through a simple, cost-effective and environmentally friendly leaf-templated strategy. The ...Co3O4 nanoparticles (30–100nm) with irregular shapes were interconnected with each other to form a 3D multilayer porous network structure, which provided high specific surface area and numerous electrocatalytic active sites. Subsequently, Co3O4 was successfully utilized as direct electrochemical sensing interface for non-enzymatic detection of H2O2 and glucose. By using chronoamperometry, the current response of the sensor at +0.31V was linear with H2O2 concentration within 0.4–200μM with a low limit of detection (LOD) of 0.24μM (S/N=3) and a high sensitivity of 389.7μAmM−1cm−2. Two linear ranges of 1–300μM (with LOD of 0.1μM and sensitivity of 471.5μAmM−1cm−2) and 4–12.5mM were found at +0.59V for glucose. In addition, the as-prepared sensor showed excellent stability and anti-interference performance for possible interferents such as ascorbic acid, uric acid, dopamine, acetaminophen and especially 0.15M chloride ions. Similarly, other various metal oxide nanostructures may be also prepared using this similar strategy for possible applications in catalysis, electrochemical sensors, and fuel cells.
•Synthesis of 3D hierarchical porous Co3O4 nanostructure by leaf-template.•The Co3O4 nanostructure was used as direct electrochemical sensing interfaces.•H2O2 and glucose sensor with high performance was prepared.
•An interesting hysteresis phenomenon was analyzed using entropy production theory.•A function was used to calculate the entropy production in the wall region.•Generation mechanism of the hump and ...hysteresis characteristics was obtained.
The hydraulic loss due to friction and unstable flow patterns in hydro-turbines causes a drop in their efficiency. The traditional method for analyzing the hydraulic loss is by evaluating the pressure drop, which has certain limitations and cannot determine the exact locations at which the high hydraulic loss occurs. In this study, entropy production theory was adopted to obtain a detailed distribution of the hydraulic loss in a pump-turbine in the pump mode. In the past, the wall effects of entropy production were not considered, which caused larger errors as compared with the method of pressure difference. First, a wall equation was proposed to calculate the hydraulic loss in the wall region. The comparison of hydraulic loss calculated by entropy production and pressure difference revealed a better result. Then, through the use of the entropy production theory, the performance characteristics were determined for a pump-turbine with 19mm guide vane opening, and the variation in the entropy production was obtained. Recently, an interesting phenomenon, i.e., a hysteresis characteristic, was observed in the hump region in pump-turbines. Research shows that the hysteresis characteristic is a result of the Euler momentum and hydraulic loss; the hydraulic loss accounts for a major portion of the hysteresis characteristic. Finally, the hysteresis characteristic in the hump region was analyzed in detail through the entropy production. The results showed that the hump characteristic and the accompanying hysteresis phenomenon are caused by backflow at the runner inlet and the presence of separation vortices close to the hub and the shroud in the stay/guide vanes, which is dependent on the direction of discharge.
Periodic stripe patterns are ubiquitous in living organisms, yet the underlying developmental processes are complex and difficult to disentangle. We describe a synthetic genetic circuit that couples ...cell density and motility. This system enabled programmed Escherichia coli cells to form periodic stripes of high and low cell densities sequentially and autonomously. Theoretical and experimental analyses reveal that the spatial structure arises from a recurrent aggregation process at the front of the continuously expanding cell population. The number of stripes formed could be tuned by modulating the basal expression of a single gene. The results establish motility control as a simple route to establishing recurrent structures without requiring an extrinsic pacemaker.
PDF
