Search

A high-performance fluorescent "turn-on" aptasensor (Eu-MOFs@SMZ-Apt) for sulfamethazine (SMZ) determination was designed using dual-emitting europium metal-organic frameworks (Eu-MOFs) as a signal transducer and an amplifier. Eu-MOFs featuring dual emission peaks (430 nm and 620 nm) were first prepared via a facile self-assembly strategy employing Eu (III) ions and 2-aminoterephthalic acid as precursors. The high-affinity aptamer was bonded with Eu-MOFs to form Eu-MOFs@SMZ-Apt through the amidation reaction. Benefiting from the integration of inherent virtues from Eu-MOFs and aptamer, the Eu-MOFs@SMZ-Apt-based sensor allowed sensitive and selective determination of SMZ with good linear relationships in a range of 1.4–40 ng mL−1 and a low detection line (0.379 ng mL−1). This sensor was successfully applied to the determination of trace SMZ in real samples with satisfactory recoveries (86.47–113.52%) and a relative standard deviation (<6.51). Consequently, the Eu-MOFs@SMZ-Apt ratiometric fluorescence sensor furnishes new possibilities for the accurate detection of various pollutants in food. [Display omitted] • A novel fluorescent "turn-on" aptasensor, Eu-MOFs@SMZ-Apt, was first constructed. • Dual-emitting Eu-MOFs, a signal transducer and amplifier, boosted the sensitivity. • High-affinity aptamer endowed Eu-MOFs@SMZ-Apt with superior specificity for SMZ. • The aptasensor achieved accurate ratiometric fluorescence detection of SMZ. [ABSTRACT FROM AUTHOR]

Silica particles can cause silicosis, a disease characterized by diffuse fibrosis of the lungs. Various signaling pathways composed of different types of cells and cytokines are involved in the development of silicosis. Exosomes have become a research hotspot recently. However, the role of exosomal microRNA (miRNA) in silicosis remains unclear. In this study, we generated exosomal miRNA sequences from exosomes isolated from bronchoalveolar lavage fluid (BALF) of silicosis patients and the control group by high-throughput sequencing. Functional annotation and analysis of miRNA identified key target miRNAs. Levels of target miRNAs were analyzed in patient and animal samples and cells. Effects of increased miRNA were assessed through protein levels in target signaling pathways in cells treated with silica, miRNA mimics, and inhibitors. Our study identified 40 up-regulated and 70 down-regulated miRNAs, with miR-552–3p and its putative target gene Caveolin 1 (CAV1) as targets for further research. We found that the levels of exosomal miR-552–3p increased in silicosis patients' BALF samples, silicosis model mice, and A549 cells exposed to silica. Inhibition of miR-552–3p suppressed the expression of fibrosis markers. The increased miR-552–3p leads to the up-regulation of fibronectin and α-smooth muscle actin (α-SMA) and the suppression of caveolin 1 in fibroblast cells. Mitogen-activated protein kinase (MAPK) signaling pathways are activated in cells treated with silica and miR-552–3p mimics. These results help to understand exosomal miRNA-mediated intercellular communication and its key role in fibroblast activation and silicosis. [Display omitted] • This study identifies exosome-induced fibroblast proliferation in silicosis BALF. • The pro-fibrosis impact of epithelial cell-derived exosomes on fibroblasts is documented. • Observations show elevated miR-552-3p expression in silica-exposed A549, HPAEpiC cells, and their exosomes. • Study associates miR-552-3p upregulation with silicosis, confirms CAV 1 binding. • Exosome transport of epithelial miR-552-3p to fibroblasts results in phenotype transdifferentiation. [ABSTRACT FROM AUTHOR]

One bis-imidazolium salt 2,2′-di[2"-(N -methyl-imidazoliumyl)ethoxyl]azobenzene hexafluorophosphate (LH 2 ·(PF 6) 2) and its macrometallocycle binuclear N-heterocyclic carbene silver(I) complex [(LAg) 2 ](PF 6) 2 were prepared and characterized. The structure of [(LAg) 2 ](PF 6) 2 was determined by X-ray single crystal diffraction, 1H NMR and 13C NMR spectroscopy. In complex [(LAg) 2 ](PF 6) 2 , one 34-membered macrometallocycle was formed by two biscarbene ligand L and two silver(I) ions. Additionally, the selective recognition of hydrogen sulfate using [(LAg) 2 ](PF 6) 2 as a chemosensor was investigated on the basis of fluorescence titrations, ultraviolet titrations, 1H NMR titrations, HRMS and IR spectra. Complex [(LAg) 2 ](PF 6) 2 was demonstrated to be an effective chemosensor for hydrogen sulfate. Macrometallocycle NHC Ag(I) complex 1 was prepared and characterized, and it was turned out to be an effective chemosensor for HSO 4 −. Image 1 [ABSTRACT FROM AUTHOR]

Reliable estimates of ocean surface waves and their long-term global trends are fundamentally important for numerous ocean engineering and geophysical applications. Nonetheless, it is scientifically and technically demanding to accurately identify such relatively small trends [ O (0. 1 − 1) cm yr−1] from wave data currently available. In 2022, Young and Ribal demonstrated that by changing the calibration method, multiplatform altimeter observations yield noticeable differences in wave height estimates and their trends. In this paper, we use our global wave hindcast as a baseline and confirm that observations calibrated relative to one another (i.e., "altimeter-altimeter" calibration) ultimately outperform traditionally "altimeter-buoy" calibrated data. The former leads to more consistent mean and extreme wave heights across simultaneously operating altimeters and consequently to a more homogeneous evolution of global sea states over the past several decades. The underlying reason is hypothesized to be that temporal inhomogeneities in long-term NDBC buoy records due to changes in buoy hardware and software over time introduce comparable inhomogeneities to long-term altimeter observations when the "altimeter-buoy" calibration is adopted. It is encouraging to observe that the global trends of mean and 90th-percentile wave heights over the period 1992-2019 from our hindcast and re-calibrated altimeter data are very close: approximately 0.3 cm yr−1. Nonetheless, the altimeter-based trend of 99th-percentile wave height, H s 99 , is substantially-but-spuriously stronger mainly due to markedly growing availability of altimeter missions over time. Our work clearly demonstrates the power of third generation spectral wave models as diagnostics tools. Given the uncertainties embedded in buoy and satellite observations, wave modeling and global wave hindcasts can indeed guide these measurements. Further analysis of the underlying climate physics driving the interannual variability of ocean waves in wind-sea dominated regions is also presented. • Investigation of global wave height climatology and trends from altimeter and model. • Intercomparison of two calibration methods of altimeter wave observations. • The "altimeter-altimeter" calibration outperforms the "altimeter-buoy" calibration. • Inhomogeneity clearly exists in the long-term NDBC buoy records. • Impact of large-scale climate physics on the interannual variability of ocean waves. [ABSTRACT FROM AUTHOR]

Using the well-observed hurricane case Ivan (2004) as an example, we investigate and intercompare the performance of two wave models under hurricane conditions. One is the WAVEWATCH III model (WW3) and the other is the University of Miami Wave Model (UMWM). Within WW3, four different source term packages (ST2/3/4/6) of wind input, wave breaking dissipation and swell decay are chosen for comparison purposes. Based on the comparisons between model results and measurements from various platforms, we concluded that UMWM shows less accuracy than WW3 in specification of bulk wave parameters. This is possibly because (i) UMWM-estimated drag coefficient does not clearly show a saturation trend when wind speeds are beyond  ∼ 35 m s − 1 and (ii) the four-wave interaction term of UMWM disagrees evidently with the full solution of the Boltzmann integral in detail. Among the four WW3 source term packages, the older parameterization ST2 is basically the least accurate because of its systematic underestimation of high waves. The remaining three packages (ST3/4/6) are performed well under Ivan. However, we also find that they tend to overestimate energy of waves traveling in the oblique and opposing winds. It is shown that enhancing the strength of negative wind input properly can effectively improve model skills in such situations. Limited by the uncertainty in the wind forcing, we could not determine the most accurate package among ST3/4/6 unambiguously. [ABSTRACT FROM AUTHOR]

Two new benzimidazolium salts with the same cationic moiety and different anionic moieties 2-[2′-( N -benzyl-benzimidazoliumyl)]-1,4-dihydro-naphtho[1,8- ef ]-1,4-diazepine bromide ( 1 ) and 2-[2′-( N -benzyl-benzimidazoliumyl)]-1,4-dihydro-naphtho[1,8- ef ]-1,4-diazepine hexafluorophosphate ( 2 ) were prepared and characterized. The structure of 1 was determined by X-ray single crystal diffraction and 1 H NMR and 13 C NMR spectroscopy. Selective recognition of 2 for cations (Li + , Na + , K + , NH 4 + , Ag + , Ca 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Cr 3+ , Cd 2+ , Al 3+ , Pb 2+ , Hg + and Hg 2+ , and use of their nitrate salts) was investigated by fluorescence and UV/vis titrations in C 2 H 5 OH/H 2 O (v:v = 1:1) at 25 °C. The response of 2 to Cu 2+ can be observed through both remarkable fluorescence enhancement and color change under sunlight (from yellow to red). The results indicated that 2 can distinguish Cu 2+ from other cations via the instrument and naked eyes, and this is greatly convenient in practical operation. [ABSTRACT FROM AUTHOR]

As a hopeful solvent, ionic liquids with tremendous combination of functional chemical sites in the cations and anions can make the separation process efficiently and selectively. Thus, to test the effect of the functional chemical sites in the cations and anions on extracting typical heterocyclic N -compound, indole was adopted as the representative compounds due to its high content and valuable application. In present work, NMP-based IL, [EtOHpyr][BuRA], with dual functional chemical sites was designed and employed to separate indole from diverse resources. The mechanism for the separation process was explored, the IL is evaluated to separate indole with the polarity analysis based on the COSMO-SAC model. Molecular dynamics simulation analysis contributed to understand the H-bonds interaction between indole and IL more indicative. The results demonstrated that the H-bonds between indole and dual functional chemical sites in [EtOHpyr][BuRA] served as the key driving force during the separation process. To validate the effect of functional chemical sites, [EtOHpyr][BF 4 ], [Etpyr][BuRA] and [Etpyr][BF 4 ] were also used for comparison. Furthermore, the influence of extraction of NMP-based ILs on indole, mass ratio (IL: model oil) and extraction temperature were investigated. Under the optimal conditions (25 ℃, mass ratio = 1:5), [EtOHpyr][BuRA] showed the best performance among those four ILs, which extraction efficiency can reach up to 95.15 wt%. The results agreed with the simulation results well. This work can provide an efficient designed ILs for the extraction of indole. [Display omitted] • The designed [EtOHpyr][BuRA] with dual functional chemical sites was used to separate indole. • The extraction mechanism was explored by MD simulations and QC calculations. • H-bonds between indole and [EtOHpyr][BuRA] served as the key driving force. • [EtOHpyr][BuRA] has the highest extraction efficiency of 95.15% among the four ILs. [ABSTRACT FROM AUTHOR]

The parameterization of air–sea CO 2 transfer velocity employed in the estimation of bulk fluxes over global ocean is typically established on wind speed but could suffer from the deviations induced by sea states. In this study, the effectiveness of wave-based formulations are substantiated by reproducing climatological air–sea CO 2 flux and gas transfer velocity. Sea states play a significant role in facilitating CO 2 transfer, particularly in mid to high latitude regions with high wind speeds. The variability in transfer velocity induced by sea states is estimated up to 19% at the wind speed of 15 m/s. The two wave-based formulations used in this study are combined using a critical value of the Reynolds number. The combined formulation further improves estimates of the CO 2 gas transfer velocity. • Wave-based parameterizations are effective in estimating global air–sea CO 2 transfer. • Sea states become important to CO 2 gas transfer at high wind speeds. • Variability in CO 2 transfer velocity induced by sea states can be evaluated. [ABSTRACT FROM AUTHOR]

One tetra-imidazolium salt (2) based on quinoxaline was prepared and characterized, and the detection of anions by compound 2 as a chemosensor was researched through fluorescence spectra, UV/Vis spectra, 1H NMR titrations, MS and IR spectra. The experimental results displayed that sensor 2 can selectively recognize F− through the instrument or the naked eyes (the color changed from colorless to brown in visible light). The high K value (6.4 × 104 M−1) for 2 F− indicated that 2 had strong bonding force to F−. The low detection limit (1.84 × 10−7 mol/L) indicated that the detection of F− by 2 was sensitive. One tetra-imidazolium salt was prepared, and its selective recognition for F- was investigated. [Display omitted] • A new tetra-imidazolium salt based on quinoxaline (2) was prepared and characterized. • The selective recognition of 2 to fluoride ion was investigated. • Compound 2 had high sensitivity for the detection of F− with the detection limit of 1.84 × 10−7 M mol/L. • The association constant of 2 F− was 6.4 × 104 M−1, which indicated that 2 had strong bonding force to F−. [ABSTRACT FROM AUTHOR]

Ocean waves and sea ice properties are intimately linked in the marginal ice zone (MIZ), nevertheless a definitive modelling paradigm for the wave attenuation in the MIZ is missing. The evolution of wave directional properties in the MIZ is a proxy for the main attenuation mechanism but paucity of measurements and disagreement between them contributed to current uncertainty. Here we provide an analytical evidence that viscous attenuation tilts the mean wave direction orthogonal to the sea ice edge and the narrows directionality. Departure from this behaviour are attributed to bimodality of the spectrum. We also highlight the need for high quality directional measurements to reduce uncertainty in the definition of the attenuation rate. • The spatial evolution of directional wave properties in sea ice is studied. • Viscous loss is applied synthetic spectra and measured Southern Ocean sea states. • Direction turns orthogonal to the sea ice edge but can deviate in bimodal seas. • Directional spread is reduced in all cases. • Directional spectra lose less energy compared to equivalent 1D spectra. [ABSTRACT FROM AUTHOR]

Abstract Nighttime cool skin sea surface temperature (SST) signals, defined in this study as the differences between the SST skin from the Advanced Along-Track Scanning Radiometer (AATSR) onboard Envisat satellite and in situ SSTs from drifting buoys and moorings, ΔT = SST skin − SST insitu , are investigated on a global scale from July 2002 to April 2012. Global mean ΔT, averaged over the full study period, is −0.13 K, with most values falling between −0.1 and −0.2 K. The dominant role of wind speed on the ΔT is shown, with weaker winds usually corresponding to a cooler skin. The effect of air-sea temperature difference is also significant: warm skin (ΔT > 0 K) can be observed under large positive air-sea temperature differences. Other geophysical variables, such as the total column water vapor, in situ SST, and net heat flux, also affect ΔT, but to a lesser degree. Significant increase of ΔT size with SST insitu is observed when SST insitu is >28 °C. Tropical waters, such as the tropical Indian Ocean and the tropical warm pool (western Pacific and eastern Indian Ocean), are more frequently covered with a cool skin, largely due to the calm winds, very warm waters (especially for SST insitu >28 °C), and other environmental conditions supporting the development of large cool skin events. The ΔT seasonal pattern in the southern hemisphere is more regular, compared to the northern hemisphere. In both hemispheres, larger cool skin signals are seen during the local summer, mainly due to weaker winds. According to several previous cool skin models, higher winds tend to result in thinner cool skin layer depths, and hence in smaller ΔT amplitudes, regardless of stronger evaporation and heat loss. Given that wind is closely coupled with waves and turbulent mixing with wave breaking, the dependencies of ΔT on a few wave parameters are also investigated. A strong (moderate) dependency of ΔT on wave height (wave steepness) is identified, while the dependency of ΔT on wave breaking probability is less discernible. Highlights • Characterization of cool skin signals on a global scale for nearly 10 years • Investigation of cool skin dependencies on different meteorological variables • Spatial and seasonal patterns of cool skin signals • Initial investigation into relationships between skin effect and wave variables [ABSTRACT FROM AUTHOR]

In this study, a third-generation ocean wave model (WAVEWATCH III; WW3) implemented on a high-resolution unstructured grid was developed to investigate wave energy in the south-east of Australia over the 40-year period from 1981 to 2020. The simulated wave power shows good agreement with values estimated from multiplatform satellite data. Thus, the modeled data were used to study statistics (mean conditions, seasonality, extremes, and long-term trends) of wave power in the domain, which show impacts of Southern Ocean swell and protection provided by the land mass of Tasmania. The results indicate increasing wave power trends, with the largest values in the southeastern part of the domain over the 40-year period. These positive trends are mainly a result of an increase in significant wave height rather than peak wave period. By utilizing the simulated wave properties, we estimated regional annual electric power at 14 coastal locations using 9 typical wave energy converters (WECs). To do so, we conducted a comprehensive analysis (seasonal variations, wave power roses, probability distributions, and bivariate probability distributions) at these locations. The results demonstrate that the western and southwestern coasts of the domain are promising generation sites but with large seasonal variability. The central and eastern coasts are protected by Tasmania, and exhibit more stable conditions but are far less energetic for electricity production. This study has critical implications for the region, which provides a benchmark for coastal WEC deployment. [ABSTRACT FROM AUTHOR]

Swell dissipation can influence air-sea interactions and is an error source in numerical models. Remote sensors, including altimeters and synthetic aperture radars, were employed to estimate swell dissipation rates in previous studies. A detailed error analysis is conducted here to better understand the results of these studies. With the help of a numerical model, we find that the point source model cannot separate swell dissipation from frequency dispersion and angular spreading effectively. Monte Carlo simulations of remotely sensing an ideal swell packet show that the accuracy of the estimated dissipation rate depends on the number, the span, and the wave height error of the observations on the swell track. The results also demonstrate that the dependence between estimated dissipation rates and wave steepness is an inherent relation from the fitting process which cannot prove that the boundary-layer turbulence is the leading reason for swell dissipation. Both the point source and the measurement errors of wave heights cause large errors of estimated dissipation rates. Comparing the overall error with the estimated dissipation rates, this study shows that the present swell tracking scheme using satellite data is sufficient to estimate a mean dissipation rate statistically through many swell tracks but is insufficient for case studies of swell dissipation. Besides, a buffer analysis shows that islands might cause more potential errors in many swell tracks used in previous studies, and ideal locations for future experiments are also identified. More advanced techniques are required for a better understanding of swell dissipation. [ABSTRACT FROM AUTHOR]

A high-resolution third-generation wave model based on unstructured grids, WAVEWATCH III, was used to investigate the wave climate of Bass Strait and South-East Australia over the period 1981 to 2020. The model results are extensively validated against a network of coastal buoys and demonstrate that the model can capture the overall wave characteristics in this region. Analyses of model outputs across the 40-year period show that significant wave height has increased by approximately 5% and a slight counterclockwise rotation of peak wave direction has occurred with likely implications for coastal processes. Seasonal variations show higher significant wave height in winter compared to summer, which is driven by dominant Southern Ocean swell. The peak wave direction in the eastern region shifts from south-westerly in winter to south-easterly in summer. In autumn and winter, there is a statistically significant correlation between wave conditions and the Southern Annular Mode. During these seasons, a southward movement of Southern Ocean low pressure systems is associated with increased significant wave height, an increase in the peak wave period and a counterclockwise rotation of the peak wave direction. • High-resolution wave model for SE Australia validated against extensive buoy data. • Mean, seasonal, and extreme wave conditions are examined. • Trends over the last 40-years show an increasing wave climate. • Changes in Southern Ocean swell have a major impact on the local wave climate. • Sheltering in the region results in high spatial gradients in wave climate. [ABSTRACT FROM AUTHOR]

Indonesia is an archipelago country with great potential for marine renewable energy, particularly for wave energy. This study will provide a wave energy assessment of Indonesia over a 6.5-year period (2011–2017) with resolution about 5.5 km. This assessment is based on data generated with a two-way nested high-resolution wave model WAVEWATCH III with observation-based physics (ST6). Three grids have been generated, namely a 'high resolution' of 3 arc-minute (0.05°) grid is nested inside a 12 arc-minute (0.2°) grid which is nested within a 0.5° global grid. Validations against altimeters and buoys show good agreement with the model. Mean wave energy has been classified based on meteorological seasons and it is found that the most energetic months are June, July, August for all areas of south, southwest and west of Indonesia where it can exceed 30 kW/m. In some locations wave energy is available throughout the entire year, that is in the south of Jawa island, Bali island and West Nusa Tenggara while in the region of west Sumatera, promising wave energy is available during the time from March to November. In addition, within the Indonesian Archipelago the monthly variations are about 5 kW/m and relatively small in terms of absolute values but this region is large relative to the mean wave power energy. • Wave energy assessment for Indonesian archipelago with spatial resolution of 0.05°. • Based on a dynamically downscaled wave model with observation-based physics (ST6). • Mean wave power in excess of 30 kW/m was found for season June to August. • 10% of mean wave power exceeds 40 kW/m with the top-one percent up to 60 kW/m. [ABSTRACT FROM AUTHOR]

The sea state of the Beaufort and Chukchi seas is controlled by the wind forcing and the amount of ice-free water available to generate surface waves. Clear trends in the annual duration of the open water season and in the extent of the seasonal sea ice minimum suggest that the sea state should be increasing, independent of changes in the wind forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves are more common in years with less summer sea ice and/or a longer open water season, and peak wave periods are generally longer. The increase in wave energy may affect both the coastal zones and the remaining summer ice pack, as well as delay the autumn ice-edge advance. However, trends in the amount of wave energy impinging on the ice-edge are inconclusive, and the associated processes, especially in the autumn period of new ice formation, have yet to be well-described by in situ observations. There is an implicit trend and evidence for increasing wave energy along the coast of northern Alaska, and this coastal signal is corroborated by satellite altimeter estimates of wave energy. [ABSTRACT FROM AUTHOR]

Abstract: Retinol-Binding Protein 4 (RBP4) is a plasma protein that transports retinol (vitamin A) from the liver to peripheral tissues. This Letter highlights our efforts in discovering the first, to our knowledge, non-retinoid small molecules that bind to RBP4 at the retinol site and reduce serum RBP4 levels in mice, by disrupting the interaction between RBP4 and transthyretin (TTR), a plasma protein that binds RBP4 and protects it from renal excretion. Potent compounds were discovered and optimized quickly from high-throughput screen (HTS) hits utilizing a structure-based approach. Inhibitor co-crystal X-ray structures revealed unique disruptions of RBP4–TTR interactions by our compounds through induced loop conformational changes instead of steric hindrance exemplified by fenretinide. When administered to mice, A1120, a representative compound in the series, showed concentration-dependent retinol and RBP4 lowering. [Copyright &y& Elsevier]

Abstract: GPR142 is a novel GPCR that is predominantly expressed in pancreatic β-cells. GPR142 agonists potentiate glucose-dependent insulin secretion, and therefore can reduce the risk of hypoglycemia. Optimization of our lead pyridinone-phenylalanine series led to a proof-of-concept compound 22, which showed in vivo efficacy in mice with dose-dependent increase in insulin secretion and a decrease in glucose levels. [Copyright &y& Elsevier]