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The two-step strategy screening based high throughput calculation is an effective method to search for highly active single atom catalysts (SACs) for efficient nitrogen reduction reaction (NRR), sharing a common feature of active metal centers MN4. However, this method faces the lack of descriptor for designing SACs due to limited data. Herein we proposed a robust empirical rule to estimate 312 credible limiting potentials for NRR over 104 C3N-supported SACs. It is found that the limiting potential scales clearly with the adsorption free energies of two key reaction intermediates (∗N2H and ∗NH2), which are significantly dependent on the structure relating descriptor φ, and the activity of SACs with and without N coordination exhibits similar catalytic efficiency. We identified four high-performance SACs having moieties of CrC2N2, CrC4, MnC4 and OsC4 with high selectivity towards NRR and competitive limiting potentials of −0.40, −0.45, −0.53 and −0.54 V, respectively. The φ values for these four SACs are around 19–25 which fall within its optimal ranges of 20–25 validating its prediction fidelity. This work broadens the discovery of two-dimensional carbon-nitrides supported SACs free of N coordination towards efficient N2 reduction and opens a new route of descriptor-guided design of efficient SACs for electrocatalysis process.

Estimating future temporal patterns of Surface Urban Heat Islands (SUHIs) on multiple time scales is an ongoing research endeavor. Among these time scales, estimation of next-day SUHIs is of special significance to urban residents, yet we currently lack a simple but efficient approach for making such estimations. In the present study, we propose a statistical strategy for estimating next-day nighttime SUHIs, based on incorporating various SUHI controls into a support vector machine regression (SVR) model. The majority of both the surface controls (including factors related to land cover and solar radiation) and meteorological controls (including temperature fluctuations, relative humidity, accumulated precipitation, wind speed, aerosol optical depth, and soil moisture) that have previously been found to account for daily SUHI variations were used as estimators, and we provide estimations for both the overall SUHI intensity (SUHII) and pixel-by-pixel Gaussian-based LSTs over 59 Chinese megacities. For the overall SUHII, the mean absolute error (MAE) is 0.67 K on average, and the mean absolute percentage error (MAPE) is no more than 25% for more than 90% of the cities. For the pixel-by-pixel LSTs, the associated MAE is less than 2.0 K in most scenarios. In addition, the contribution from each selected estimator to SUHII estimation is assessed comprehensively. Among all the estimators, the contribution from relative humidity is the greatest, followed by rural surface temperature and surface air temperature. Moreover, for nearly 78% of the cities, the estimators related to day-to-day SUHI variations make a larger contribution than those related to intra-annual SUHI variations. We conclude that our simple yet effective statistical approach for estimating next-day SUHIs can potentially help urban residents to better adapt to urban heat stress.

Amyloid β peptide (Aβ) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Currently, decreasing Aβ production and preventing Aβ aggregation are thought to be important strategies in anti-AD therapy. However, inhibiting Aβ production or aggregation in isolation is not sufficient to reverse the neurodegenerative process of AD patients in clinical testing. Here, a self-assembly molecular chaperone (SAMC) consisting of γ-secretase inhibitor DAPT and mixed-shell polymeric micelles is devised, serving as a bifunctional suppressor of AD. This two-in-one combinational system can simultaneously inhibit Aβ production and aggregation, which would contribute to enhancing the therapeutic effect by decreasing Aβ levels. Decorating a neuron-specific RVG29 peptide onto the surface, the DAPT-incorporated SAMC can specifically target neuronal cells and, thus, will relieve the strong side effect of DAPT on normal cells. Therefore, this combination strategy holds great potential to open up an avenue for AD treatment.

The ever-increasing space exploration enterprise calls for novel and high-quality radiation-resistant materials, among which nonlinear optical materials and devices are particularly scarce. Two-dimensional (2D) materials have shown promising potential, but the radiation effects on their nonlinear optical properties remain largely elusive. We previously fabricated 2D bismuthene for mode-locking sub-ns laser; herein, their space adaption was evaluated under a simulated space radiation environment. The as-synthesized thin layers of bismuthene exhibited strong third-order nonlinear optical responses extending into the near-infrared region. Remarkably, when exposed to 60Co γ-rays and electron irradiation, the bismuthene showed only slight degradation in saturable absorption behaviors that were critical for mode-locking in space. Ultrafast spectroscopy was applied to address the radiation effects and damage mechanisms that are difficult to understand by routine techniques. This work offers a new bottom-up approach for preparing 2D bismuthene, and the elucidation of its fundamental excited-state dynamics after radiation also provides a guideline to optimize the material for eventual space applications.

Background Lignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth. Results Here, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance. Conclusions The microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries. How to cite: Bai D, Lin X, Hu Y, et al. Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum. Electron J Biotechnol 2021;50. https://doi.org/10.1016/j.ejbt.2020.12.001

Given detrimental impacts induced by estrogens at trace level, determination of them is significant but challenging due to their low content in environmental samples and inherent weak ionisation. A modified derivatisation-based methodology was applied for the first time to detect estrogen in free and conjugated forms including some isomers simultaneously using liquid chromatography tandem mass spectrometry (LC-MSn). Derivatisation reaction with previously used 1,2-dimethyl-1H-imidazole-5-sulphonyl chloride allowed significant increase of mass spectrometric signal of analytes and also provided distinctive fragmentation for their confirmation even in complicated matrix. Then satisfactory recovery (>75%) for the majority of analytes was achieved following optimisation of solid phase extraction (SPE) factors. The linearity was validated over a wide concentration with the correlation coefficient around 0.995. The repeatability of this methodology was also confirmed via the intra-day and inter-day precision and was less than 11.73%. Validation of method quantification limits (MQLs) for all chosen estrogens was conducted using 1000 mL surface water, ranging from 7.0 to 132.3 pg L−1. The established methodology was applied to profile presence of targeted estrogens in natural surface water samples. Out of the ten compounds of interest, three free estrogens (E1, E2, E3) and two sulphate estrogens (E1-3S and E2-3S) were found over their MQLs, being in the range of 0.05–0.32 ng L−1.

Connectivity evaluation of fracture networks is important in the design, assessment, and development of reservoirs in various engineering applications involving geothermal exploitation and the petroleum industry. By employing nonhomogeneous Poisson distribution and annealing arithmetic, this study generates fracture networks that fit well with actual outcrop fracture data. Based on Allard's definition of the connectivity index, a weighted factor is introduced, and an extended connectivity evaluation method is proposed to consider the effects of the aperture and its correlation with trace length. The results of the analysis show that the extended method improves the accuracy and reliability of connectivity evaluation compared with the traditional method. Moreover, the extended method is effective and accurate at predicting potential preferential flow paths in a practical example of the Dragon and Tiger Mountain (Jiangxi, China), and can better show the anisotropy with a change in the aperture. Hence, the proposed method extends the function of connectivity analysis and can benefit well location optimization in geothermal or petroleum exploration.

Statistical downscaling of land surface temperature (SDLST) algorithms with diverse scaling factors and regression models have been used to produce high spatial resolution LSTs based on Landsat-8 LST. However, the optimal choice of scaling factors and regression models and their associated combinations over various land surfaces, especially from a global perspective, remain unclear and even controversial. To cope with this issue, we compare 35 SDLST algorithms derived from a combination of seven scaling factors and five frequently used regression models over 32 geographical regions worldwide. The seven scaling factors, at varying degrees, make use of the LST-related information embedded within the visible and near-infrared and short-wave infrared bands of Landsat-8 data. The five regression models involved are multiple linear regression, partial least squares regression, artificial neural networks, support vector regression, and random forest (RF). Our main findings are: (1) The performance of the scaling factors and regression models are highly dependent on each other. Nevertheless, for most scaling factors, especially for high-dimension scaling factors with numerous LST-related variables, the downscaling algorithms that use RF as the regression model achieve the highest accuracy. (2) RFT21, a newly proposed SDLST algorithm based on the comparison results and further optimization, has high global operability and sufficiently high accuracy. RFT21 requires only Landsat-8 data as the inputs, and achieves the highest accuracy in comparison with the thermal sharpening (TsHARP) and high-resolution urban thermal sharpener (HUTS) algorithms, with the mean root-mean-square error (RMSE) reduced by more than 15%. These findings will facilitate the generation of high spatial resolution LSTs worldwide and associated applications.

Adiponitrile (ADN) is an important raw material to produce nylon 66, and can be produced by electrodimerization of acrylonitrile (AN). The commercial processes are operated in flow systems. It is the first time that a rotating rod electrode (RRE), a relatively simple tool, was applied in the electrosynthesis of ADN. The electrode rotation rate was used to simulate high electrolyte velocity in the flow cell systems used in the industry. In addition to AN and ADN, the concentrations of two major by-products, propionitrile (PN) and trimer, were measured to determine the selectivity and current efficiency. Among five investigated quaternary ammonium salts in the electrolyte, tetrabutylammonium hydroxide (TBAP) possessing the smallest hydrophilic ability and hydrophilic-lipophilic balance (HLB) showed the best performance in the selectivity and current efficiency of ADN. A higher electrode rotation rate provided faster mass transport of AN and promoted the production of oligomers, particularly ADN. Higher current density favored the production of PN. The highest selectivity (85%), current efficiency (82%) and highest yield (0.331 g/cm2·hr) of adiponitrile were accomplished at 3000 rpm, corresponding to a velocity of 1.25 m/s in the range of the electrolyte flow velocity in commercial processes that other researches cannot easily reach it.

Glioblastoma (GBM) is a common and aggressive brain tumor with a median survival of 12-15 months. Temozolomide (TMZ) is a first-line chemotherapeutic agent used in GBM therapy, but the occurrence of drug resistance limits its antitumor activity. The natural compound cedrol has remarkable antitumor activity and is derived from Cedrus atlantica. In this study, we investigated the combined effect of TMZ and cedrol in GBM cells in vitro and in vivo. The TMZ and cedrol combination treatment resulted in consistently higher suppression of cell proliferation via regulation of the AKT and MAPK signaling pathways in GBM cells. The combination treatment induced cell cycle arrest, cell apoptosis, and DNA damage better than either drug alone. Furthermore, cedrol reduced the expression of proteins associated with drug resistance, including O6-methlyguanine-DNA-methyltransferase (MGMT), multidrug resistance protein 1 (MDR1), and CD133 in TMZ-treated GBM cells. In the animal study, the combination treatment significantly suppressed tumor growth through the induction of cell apoptosis and decreased TMZ drug resistance. Moreover, cedrol-treated mice exhibited no significant differences in body weight and improved TMZ-induced liver damage. These results imply that cedrol may be a potential novel agent for combination treatment with TMZ for GBM therapy that deserves further investigation.

In this paper, martensite-to-austenite reversion during intercritical annealing was applied to a conventional low-alloy transformation-induced plasticity steel to form reverted austenite, which was followed by austempering to form bainite, and hence the resulting microstructures and mechanical properties were investigated. The obtained microstructure is composed of alternating lamellae of intercritical ferrite and reverted austenite on microscale, with the latter consisting of bainitic ferrite laths and retained austenite films on nanoscale. This unique microstructure exhibits excellent strength–ductility combinations, which surpass those of conventional polygonal blocky-structured counterparts, providing a strategy for developing high-performance structural materials at low production cost.

Wavefield extrapolation is critical in reverse time migration (RTM). The finite difference method is primarily used to achieve wavefield extrapolation in case of the RTM imaging of tunnels. However, complex tunnel models, including those for karsts and fault fracture zones, are constructed using regular grids with straight curves, which can cause numerical dispersion and reduce the imaging accuracy. In this study, wavefield extrapolation was conducted for tunnel RTM using the finite element method, wherein an unstructured mesh was considered to be the body-fitted partition in a complex model. Further, a Poynting vector calculation equation suitable for the unstructured mesh considered in the finite element method was established to suppress the interference owing to low-frequency noise. The tunnel space was considered during wavefield extrapolation to suppress the mirror artifacts based on the flexibility of mesh generation. Finally, the influence of the survey layouts (one and two sidewalls) on the tunnel imaging results was investigated. The RTM results obtained for a simple tunnel model with an inclined interface demonstrate that the method based on unstructured meshes can effectively suppress the low-frequency noise and mirror artifacts, obtaining clear imaging results. Furthermore, the two-sidewall tunnel survey layout can be used to accurately obtain the real position of the inclined interface ahead of the tunnel face. The complex tunnel numerical modeling and actual data migration results denote the effectiveness of the finite element method in which an unstructured mesh is used.

A new organic small-molecule family comprising tetracyanoquinodimethane-substituted quinoidal dithioalky(SR)terthiophenes (DSTQs) (DSTQ-6 (1); SR = SC6H13, DSTQ-10 (2); SR = SC10H21, DSTQ-14 (3); S...

The rational design and applications of plasmon-mediated chemical reactions (PMCRs) are fundamentally determined by an understanding of photon-electron-molecule interactions. However, the current understanding of the PMCR of plasmon-decayed hot electron-mediated reactions remains implicit, since there has not been a single measurement of both hot-electron transfer and molecular transformation following photon excitation. Therefore, we invented a method called microphotoelectrochemical surface-enhanced Raman spectroscopy (μPEC-SERS) that uses an ultramicroelectrode (UME) whose dimensions match those of the focused laser spot. This system can simultaneously record the photocurrent (∼picoamps) of hot-electron transfer with a high signal-to-noise ratio and the SERS spectra of a molecular reaction in the same electrode area. The responses of the photocurrent and SERS spectra to laser illumination can correlate the surface reaction activated by hot electrons with the SERS spectral changes. A typical PMCR of

Lithium ion capacitors (LICs) are energy storage devices integrating the complementary features of both supercapacitors and lithium ion batteries to simultaneously reach high energy and power densities. One of the major challenges in LIC technology is the kinetic imbalance between the faradaic insertion anode and capacitive cathode. Therefore, the design of electrode materials is crucial to enhance the rate performance of anode and the capacitance of the cathode in LIC devices. In this work, novel LICs were demonstrated with nanostructured cathode and anode. A vertically-aligned carbon nanoflakes (VACNFs) cathode provided high electrochemically active surface area and excellent conductivity, while a metal organic framework (MOF) derived carbonized nickel cobalt oxide (cNiCo2O4) anode ensured fast conversion reactions and remarkable cyclability. Electrochemical characterization of individual electrode confirmed that both electrodes exhibited good electron and ion transport capability. The LICs were fabricated with optimized electrode active materials loading to deliver high energy densities at desired charge/discharge rates. The devices exhibited energy density up to 136.9 W h/kg (at 200 W/kg). At higher power density of 40 kW/kg, under which a full charge-discharge can be finished within 4 s, the LICs could still deliver an energy density of 26.44 W h/kg. The devices also showed a good cycle stability (≈90% capacitance retention after 9000 cycles, under current density of 4 A/g) within the voltage range of 1–4.2 V.

Surface plasmons (SPs) originating from the collective oscillation of conduction electrons in nanostructured metals (Au, Ag, Cu, etc.) can redistribute not only the electromagnetic fields but also the excited carriers (electrons and holes) and heat energy in time and space. Therefore, SPs can engage in a variety of processes, such as molecular spectroscopy and chemical reaction. Recently, plenty of demonstrations have made plasmon-mediated chemical reactions (PMCRs) a very active research field and make it as a promising approach to facilitate light-driven chemical reactions under mild conditions. Concurrently, making use of the same SPs, surface-enhanced Raman spectroscopy (SERS) with a high surface sensitivity and energy resolution becomes a powerful and commonly used technique for the in situ study of PMCRs. Typically, various effects induced by SPs, including the enhanced electromagnetic field, local heating, excited electrons, and excited holes, can mediate chemical reactions. Herein, we use the para-aminothiophenol (PATP) transformation as an example to elaborate how SERS can be used to study the mechanism of PMCR system combined with theoretical calculations. First, we distinguish the chemical transformation of PATP to 4,4'-dimercaptoazobenzene (DMAB) from the chemical enhancement mechanism of SERS through a series of theoretical and in situ SERS studies. Then, we focus on disentangling the photothermal, hot electrons, and "hot holes" effects in the SPs-induced PATP-to-DMAB conversion. Through varying the key reaction parameters, such as the wavelength and intensity of the incident light, using various core-shell plasmonic nanostructures with different charge transfer properties, we extract the key factors that influence the efficiency and mechanism of this reaction. We confidently prove that the transformation of PATP can occur on account of the oxygen activation induced by the hot electrons or because of the action of hot holes in the absence of oxygen and confirm the critical effect of the interface between the plasmonic nanostructure and reactants. The products of these two process are different. Furthermore, we compare the correlation between PMCRs and SERS, discuss different scenario of PMCRs in situ studied by SERS, and provide some suggestions for the SERS investigation on the PMCRs. Finally, we comment on the mechanism studies on how to distinguish the multieffects of SPs and their influence on the PMCRs, as well as on how to power the chemical reaction and regulate the product selectivity in higher efficiencies.

Continuous online measurements of fine particulate matter mass (PM2.5) and its chemical composition were carried out at an urban monitoring site in Wuhan from March 2017 to February 2018. The PM2.5 mass concentration ranged from 6.3 to 223 μg/m3, with the highest in winter and the lowest in summer. Water soluble ions (WSIs) were the most abundant component in PM2.5 (28.8 ± 22.9 μg/m3), followed by carbonaceous aerosol (11.9 ± 10.4 μg/m3) and elements (5.5 ± 6.7 μg/m3). It is noteworthy that six episodes of sustained high PM were observed during the study period. Five major contributors of PM2.5 were identified by positive matrix factorization (PMF) to be the iron and steel industry, fugitive dust, secondary photochemistry, traffic-related emission and biomass burning, contributing 26.3%, 5.5%, 29.5%, 29.2% and 9.6% to PM2.5, respectively. Furthermore, conditional probability function (CPF), trajectory analysis and potential source contribution function (PSCF) were used to identify the influences of local activities and regional source. Local sources mainly include Wuhan iron and steel group, construction sites and urban trunk roads, etc. Three pollution transport pathways of PM2.5 in Wuhan were identified to be northwest, east and south pathway, with the relative contribution of 40%, 17% and 43%, respectively. Western Henan, northern Shaanxi and southwestern Shanxi were identified to be the major potential source regions of PM2.5 in Wuhan.

The insufficient hydrophobicity due to difficulty in producing surface nanostructures hinders the application of thermal spraying technology for metal-based superhydrophobic coatings. In this paper, the hydrophobicity of an Al-based composite coating prepared by plasma spraying was innovatively improved by WO3 nanoparticles electroless plated on Al spraying powders and nano-oxides produced by chemical vapor deposition induced by plasma spraying (PS-CVD). Results showed that Al@WO3 core-shell powder was fabricated as feedstock. A mixture of two nano-products (Al2O3 and W) was formed on the surface of the coating and the reason may be that aluminum vapor reduced WO3 to W. The effects of plasma arc current and H2 flow rate on surface morphology and wettability of the as-prepared coating were investigated. It was found that the increase in H2 flow rate and plasma arc current enhanced the generation of surface nano-products by PS-CVD, and thus improved the coating hydrophobicity. However, extremely high temperature may result in the refusion of nano-products. The highest water droplet contact angle (WCA) reached 157.0 ± 1° and the lowest water droplet sliding angle (WSA) was 7.5 ± 1°. Finally, the photocatalytic activity of the coating was tested by its performance in the degradation of methyl orange, and it was found that acidic conditions facilitated the degradation performance. The superhydrophobicity and photocatalysis performance demonstrate the potential use of the as-prepared coating in antibacterial and antifouling fields.

Complete surface passivation of CsPbBr3 quantum dots by treatment with di-dodecyldimethylammonium bromide and sodium thiocyanate is demonstrated resulting in dispersions with photostable photoluminescence of near-unity quantum yield and a lifetime of 17.5 ns. Before treatment, the photoluminescence has a quantum yield of 73% and lifetime of 9.4 ns, and decayed by 80% on exposure to ultraviolet light for an hour. When used as the photo-emitting species in a solution-processed LED structure, the surface treatment increased the maximum luminance from 550 cd.m-2 to 1200 cd.m-2, and reduced the turn-on voltage from 3.1 V to 2.8 V.

Solid-state laser lighting (SSL) fabricated by integrating laser diode with phosphor is a new development to achieve high luminance. Because of the high temperature caused by the laser, the phosphor-conversion apparatus is demanded to possess excellent thermal properties. In this paper, we utilized spark plasma sintering (SPS) to prepare the Al2O3-YAG:Ce phosphor ceramics with outstanding performances. Due to the high thermal conductivity and high transmittance, a high saturation input power (32 W/mm2) can be achieved for the sample with the lowest porosity. The correlated color temperature (CCT) and color rendering index (CRI) of composite ceramics with the lowest porosity are stable as the input power increases from 0.7 W/mm2 to 30.8 W/mm2. Nevertheless, the sample with the highest porosity shows the highest luminescence efficiency (305 lm/W) and luminous emittances (1796 lm/mm2), which can be ascribed to the scattering of the pore.

Annual temperature cycle (ATC) models enable the multi-timescale analysis of land surface temperature (LST) dynamics and are therefore valuable for various applications. However, the currently available ATC models focus either on prediction accuracy or on generalization ability and a flexible ATC modelling framework for different numbers of thermal observations is lacking. Here, we propose a hybrid ATC model (ATCH) that considers both prediction accuracy and generalization ability; our approach combines multiple harmonics with a linear function of LST-related factors, including surface air temperature (SAT), NDVI, albedo, soil moisture, and relative humidity. Based on the proposed ATCH, various parameter-reduction approaches (PRAs) are designed to provide model derivatives which can be adapted to different scenarios. Using Terra/MODIS daily LST products as evaluation data, the ATCH is compared with the original sinusoidal ATC model (termed the ATCO) and its variants, and with two frequently-used gap-filling methods (Regression Kriging Interpolation (RKI) and the Remotely Sensed DAily land Surface Temperature reconstruction (RSDAST)), under clear-sky conditions. In addition, under overcast conditions, the LSTs generated by ATCH are directly compared with in-situ LST measurements. The comparisons demonstrate that the ATCH increases the prediction accuracy and the overall RMSE is reduced by 1.8 and 0.7 K when compared with the ATCO during daytime and nighttime, respectively. Moreover, the ATCH shows better generalization ability than the RKI and behaves better than the RSDAST when the LST gap size is spatially large and/or temporally long. By employing LST-related controls (e.g., the SAT and relative humidity) under overcast conditions, the ATCH can better predict the LSTs under clouds than approaches that only adopt clear-sky information as model inputs. Further attribution analysis implies that incorporating a sinusoidal function (ASF), the SAT, NDVI, and other LST-related factors, provides respective contributions of around 16%, 40%, 15%, and 30% to the improved accuracy. Our analysis is potentially useful for designing PRAs for various practical needs, by reducing the smallest contribution factor each time. We conclude that the ATCH is valuable for further improving the quality of LST products and can potentially enhance the time series analysis of land surfaces and other applications.

For type 1 and advanced type 2 diabetic patients, insulin replacement therapy with simulating on-demand prandial and basal insulin secretion is the best option for optimal glycemic control. However, there is no insulin delivery system yet could mimic both controlled basal insulin release and rapid prandial insulin release in response to real-time blood glucose changes. Here we reported an artificial insulin delivery system, mimicking physiological basal and prandial insulin secretion, to achieve real-time glycemic control and reduce risk of hypoglycemia. A phenylboronic acid (PBA)/galactosyl-based glucose-responsive insulin delivery system was prepared with insulin-loaded micelles embedded in hydrogel matrix. At the hyperglycemic state, both the hydrogel and micelles could swell and achieve rapid glucose-responsive release of insulin, mimicking prandial insulin secretion. When the glucose level returned to the normal state, only the micelles partially responded to glucose and still released insulin gradually. The hydrogel with increased crosslinking density could slow down the diffusion speed of insulin inside, resulting in controlled release of insulin and simulating physiological basal insulin secretion. This hydrogel-micelle composite insulin delivery system could quickly reduce the blood glucose level in a mouse model of type 1 diabetes, and maintain normal blood glucose level without hypoglycemia for about 24 h. This kind of glucose-responsive hydrogel-micelle composite may be a promising candidate for delivery of insulin in the treatment of diabetes.

The Hoek–Brown (HB) failure criterion is one of the most widely used failure criteria in rock engineering. Based on the Geological Strength Index (GSI) system, a number of empirical models have been proposed in parallel with this criterion to estimate the strength and deformation properties of rock masses such as uniaxial compressive strength (UCS) and deformation modulus. However, the GSI system does not incorporate the effects of joint orientation β on the quality of a rock mass. This means that these empirical models cannot capture anisotropic rock mass strength caused by joint orientations. In this research, UDEC rock mass models, which are calibrated by laboratory data, are used to investigate the effects of joint orientation on rock mass strength in an unconfined state. The values of UCS obtained from the numerical simulation are then compared with those calculated from traditional empirical UCS models based on the GSI system. The comparison study shows that the value of UCS is significantly overestimated by the traditional empirical model when 10° < β

Nanoparticle-based combination therapy has been reported as one important treatment strategy to improve the therapeutic efficacy in cancer therapy. However, the traditional co-delivery method often suffers from serious coordination issues that fail to account for the differences in the action sites of each of the drugs, greatly counteracting the synergistic effects of combination agents. Herein, we report a pH-reduction dual responsive drug delivery system for the programmable release of combretastatin A-4 (CA4) and cis-platinum (CDDP). According to their spatial and temporal needs, such nanocarriers could firstly release CA4 in the perivascular sites by responding to the acidic microenvironment of the tumor, then further diffuse throughout the tumor and release CDDP upon redox when being taken-up by the cancer cells. With the help of such spatiotemporal release properties, CA4 and CDDP can target the endothelial cells of tumor vessels and the cancer cells in succession, giving rise to temporal and spatial synergisms. On one hand, the first released CA4 provided a complementary effect for improving tumor accumulation of nanocarriers and the delivery effect of CDDP. On the other hand, CA4 and CDDP respectively targeted their action sites, overall maximizing the therapeutic effect. More importantly, such spatiotemporal drug delivery ability is accomplished by the pH-reduction dual responsive design of the nanocarriers, and thus could also serve as a universal approach for programmable release of other combination agents to improve their synergistic effect in cancer therapy.

The prospect of developing new bio-based products from lignin partially depends on the development of effective analytical techniques to characterize the end products from lignin degradation experiments. To date, the most utilized mass spectrometric technique for characterizing lignin oligomers has been negative ion mass spectrometry. Positive ion mass spectrometry remains a relatively unexplored approach for lignin sequencing. Here we report on the sequencing of lignin oligomers using lithium cationization positive ion electrospray followed by higher-energy collisional dissociation (HCD) tandem mass spectrometry on a high-resolution accurate-mass Orbitrap mass spectrometer. Thirteen synthetic lignin model oligomers containing β-O-4 and 4-O-α linkages were analyzed and sequenced based on their HCD tandem mass spectrometry fragmentation patterns. Proposed sequence-specific fragmentation pathways are provided. The method presented in this study provides a potential application of lithium cationization tandem mass spectrometry for the analysis of lignin degradation products.

Diabetes is a chronic metabolic disorder disease characterized by high blood glucose levels and has become one of the most serious threats to human health. In recent decades, a number of insulin delivery systems, including bulk gels, nanogels, and polymeric micelles, have been developed for the treatment of diabetes. Herein, a kind of glucose and H2O2 dual-responsive polymeric nanogel was designed for enhanced glucose-responsive insulin delivery. The polymeric nanogels composed of poly(ethylene glycol) and poly(cyclic phenylboronic ester) (glucose and H2O2 dual-sensitive groups) were synthesized by a one-pot thiol-ene click chemistry approach. The nanogels displayed glucose-responsive release of insulin and the release rate could be promoted by the incorporation of glucose oxidase (GOx), which generated H2O2 at high glucose levels and H2O2 further oxidizes and hydrolyzes the phenylboronic ester group. The nanogels have characteristics of long blood circulation time, a fast response to glucose, and excellent biocompatibility. Moreover, subcutaneous delivery of insulin to diabetic mice with the insulin/GOx-loaded nanogels presented an effective hypoglycemic effect compared to that of injection of insulin or insulin-loaded nanogels. This kind of nanogel would be a promising candidate for the delivery of insulin in the future.

A graphene oxide paper (GOP) was irradiated with 500 keV proton for total fluence of 2 × 1013 cm−2 to 2 × 1015 cm−2 in a ground-based irradiation simulator. The spacing of layer, surface chemical composition, structural defects, thermal conductivity and electrical property of the GOP before and after irradiation was measured. The results indicated that the spacing of layer decreased after irradiation. The ratio of total carbon atom and total oxygen atom increased from 2.40 to 4.31 as well as the sp2 hybridized carbons obviously increased after 2 × 1015 cm−2 irradiation. The XPS analysis suggested the occurrence of reduction, and the Raman spectra indicated that the defects were produced after proton irradiation. Furthermore, the thermal conductivity of GOP decreased, and then increased smoothly as the irradiation fluences were increased, and the electrical property showed the similar trend. The change in the thermal and electrical properties for GOP could be attributed to the defects and the removal of oxygen-containing functional groups, which lead to the phonon conduct path and scattering centers changed under proton irradiation. This study could promote the application of GOP in future space expeditions.

Two diketopyrrolopyrrole (DPP)-based donor-acceptor oligomers with thermal labile 2-methylhexyl-2-oxylcarbonyl (mHoc) groups, mHocPBT and mHocTBT, were synthesized and characterized to study the hydrogen-bonding mediated molecular packing in solid state. The soluble oligomers can be converted to strong intermolecular hydrogen-bonded and pigment-like materials HPBT and HTBT by annealing the casted solid film at a temperature between 180 and 200 °C. The formation of intermolecular hydrogen bonding significantly altered the conformation of the molecules, molecular packing structure and related optical properties of the oligomers, with HPBT molecule exhibiting bathochromic shift and HTBT molecule exhibiting hypsochromic shift on UV/Vis spectra. Spin-casted mHocTBT and HTBT films also exhibited interesting morphology and charge transport properties. Even though the single mHocTBT oligomer molecule has a better coplanar molecular conformation as compared with that of HTBT, an enhanced π-π stacking structure and larger crystal grain size rendered HTBT film better charge transport performance.

Supramolecular hydrogels of self-assembling peptide-drug conjugates have been considered as effective self-delivery drug systems for cancer therapy in recent years. Here, a novel self-assembling peptide-based supramolecular hydrogel was developed by simultaneously conjugating small-molecule drug chlorambucil (CRB) and peptide drug tyroservatide (YSV) to the self-assembling peptide. The resulting hydrogel with a nanofiber structure showed enhanced stability against proteinase K degradation and an improved cellular uptake performance in comparison with the free molecules. As a consequence, it exhibited enhanced antitumor efficiency both in vitro and in vivo with favorable biocompatibility. This biocompatible self-delivery drug system could not only significantly improve the delivery efficiency of the small-molecule drugs but also adequately synergize the antitumor effect of CRB and YSV, inspiring the design of new strategies of cancer combination therapy.

In the present study, the effects of ausforming on the bainitic transformation, microstructure and mechanical properties of a low-carbon rich-silicon carbide-free bainitic steel have been investigated. Results show that prior ausforming shortens both the incubation period and finishing time of bainitic transformation during isothermal treatment at a temperature slightly above the Mspoint. The thicknesses of bainitic ferrite laths are reduced appreciably by ausforming; however, ausforming increases the amount of large blocks of retained austenite/martenisite and decreases the volume fraction of retained austenite. And accordingly, ausforming gives rise to significant increases in both yield and tensile strengths, but causes noticeable decreases in ductility and impact toughness.

Layered MoS2 is considered as one of the most promising two-dimensional photocatalytic materials for hydrogen evolution and water splitting; however, the electronic structure at the MoS2-liquid interface is so far insufficiently resolved. Measuring and understanding the band offset at the surfaces of MoS2 are crucial for understanding catalytic reactions and to achieve further improvements in performance. Herein, the heterogeneous charge transfer behavior of MoS2 flakes of various layer numbers and sizes is addressed with high spatial resolution in organic solutions using the ferrocene/ferrocenium (Fc/Fc+) redox pair as a probe in near-field scanning electrochemical microscopy, i.e. in close nm probe-sample proximity. Redox mapping reveals an area and layer dependent reactivity for MoS2 with a detailed insight into the local processes as band offset and confinement of the faradaic current obtained. In combination with additional characterization methods, we deduce a band alignment occurring at the liquid-solid interface., Here, high-resolution atomic force microscopy and scanning electrochemical microscopy are used to investigate the electron transfer behaviour of layered MoS2 flakes in organic solutions, offering insights on the electronic band alignment at the solid-liquid interface.

The accumulation of atrazine in sediments raises wide concern due to its potential negative effects on aquatic environments. Here we collected sediments and different submerged macrophytes to simulate natural shallow lakes and to measure atrazine levels and submerged macrophyte biomass. We determined gene expressions in submerged macrophytes treated with or without atrazine. We also examined atrazine concentrations and its metabolite structures in submerged macrophytes. When the initial concentration of atrazine in sediments ranged from 0.1 to 2.0 mg kg−1 dry weight (DW), atrazine levels in the pore water of the sediments ranged from 0.003 to 0.05 mg L−1 in 90 days. Atrazine did not show obvious long-term effects on the biomass of Potamogeton crispus and Myriophyllum spicatum (P > 0.05). On day 90, gene expressions related to cell wall in P. crispus were changed by atrazine phytotoxicity. Moreover, the decrease in the number genes controlling light-harvesting chlorophyll a/b-binding proteins verified the toxic effects of atrazine on the photosynthesis of M. spicatum. Compared with unexposed plants on day 90, ribosome pathway was significantly enriched with differentially expressed genes after submerged macrophytes were exposed to 2.0 mg kg−1 DW atrazine (P 0.05). Once absorbed by submerged macrophytes, atrazine was degraded into 1-hydroxyisopropylatrazine, hydroxyatrazine, deethylatrazine, didealkylatrazine, cyanuric acid, and biuret, and some of its metabolites could conjugate with organic acids, cysteinyl β-alanine, and glucose. This study establishes a foundation for aquatic ecological risk assessments and the phytoremediation of atrazine in sediments.

The aim of this study is to evaluate the effect of rare earth upconversion nanoparticles (UCNs) on hepatic ischemia reperfusion injury (IRI) and explore its possible mechanism. Hepatic IRI seriously affects the prognosis of patients undergoing liver surgery. Liver-resident Kupffer cells have been reported to promote IRI. Nanomedicines are known to be effective in the treatment of liver diseases, however, Kupffer cell-targeting nanomedicines for the treatment of IRI are yet to be developed. As potential bioimaging nanomaterials, UCNs have been found to specifically deplete Kupffer cells, but the underlying mechanism is unknown. In this study, we found that UCNs specifically depleted Kupffer cells by pyroptosis, while the co-administration of the caspase-1 inhibitor VX-765 rescued the UCN-induced Kupffer cell pyroptosis in mice. Furthermore, the pre-depletion of Kupffer cells by the UCNs significantly suppressed the release of inflammatory cytokines and effectively improved hepatic IRI. The rescue of the pyroptosis of the Kupffer cells by VX-765 abrogated the protective effect of UCNs on the liver. These results suggest that UCNs are highly promising for the development of Kupffer cell-targeting nanomedicines for intraoperative liver protection.

Zwitterionic micelles find their own path through the body to disperse an infectious biofilm and enhance antibiotic efficacy., Extracellular polymeric substances (EPS) hold infectious biofilms together and limit antimicrobial penetration and clinical infection control. Here, we present zwitterionic micelles as a previously unexplored, synthetic self-targeting dispersant. First, a pH-responsive poly(ε-caprolactone)-block-poly(quaternary-amino-ester) was synthesized and self-assembled with poly(ethylene glycol)-block-poly(ε-caprolactone) to form zwitterionic, mixed-shell polymeric micelles (ZW-MSPMs). In the acidic environment of staphylococcal biofilms, ZW-MSPMs became positively charged because of conversion of the zwitterionic poly(quaternary-amino-ester) to a cationic lactone ring. This allowed ZW-MSPMs to self-target, penetrate, and accumulate in staphylococcal biofilms in vitro. In vivo biofilm targeting by ZW-MSPMs was confirmed for staphylococcal biofilms grown underneath an implanted abdominal imaging window through direct imaging in living mice. ZW-MSPMs interacted strongly with important EPS components such as eDNA and protein to disperse biofilm and enhance ciprofloxacin efficacy toward remaining biofilm, both in vitro and in vivo. Zwitterionic micellar dispersants may aid infection control and enhance efficacy of existing antibiotics against remaining biofilm.

An intelligent carrier system is based on fast glucose response mechanism to regulate the insulin release. Here, glucose dual-responsive nanoparticles were quickly and efficiently obtained, by dynamic covalent bonds between phenylboronic acid-containing homopolymer poly(3-acrylamidophenylboronic acid) (PAAPBA) and glycopolypeptide poly(ethylene glycol)-b-poly(aspartic acid-co-aspart-glucosamine) (PEG-b-P(Asp-co-AGA)) through the formation of cycloborates. Meanwhile, insulin and glucose oxidase (GOx) were loaded during the formation of nanoparticles. The cycloborates in the nanoparticles could be destroyed by the replacement of glycosyl moieties by glucose and oxidized by H2O2 generated from the glucose-GOx system, resulting in the rapid insulin release. After subcutaneous delivery of the insulin/GOx-loaded nanoparticles to diabetic mice, a significant hypoglycemic effect was observed over time. Cytotoxicity study, hemolysis assay, and histological analyses suggested that the nanoparticles showed excellent biocompatibility and safety. This work lays the important theoretical and technical foundations for expanding the scope of applications of nanocarriers in diabetes treatment.

This paper introduces a Bayesian MCMC method, referred to as a marginalized mixture sampler, for state space models whose disturbances follow stochastic volatility processes. The marginalized mixture sampler is based on a mixture-normal approximation of the log-χ 2 distribution, but it is implemented without the need to simulate the mixture indicator variable. The key innovation is to use the filter ing scheme developed by Kim (Kim C.-J. 1994. “Dynamic Linear Models with Markov-Switching.” Journal of Econometrics 60: 1–22.) and the forward-filtering backward-sampling algorithm to generate a proposal series of the latent stochastic volatility process. The proposal series is then accepted according to the Metropolis-Hastings acceptance probability. The new sampler is examined within an unobserved component model and a time-varying parameter vector autoregressive model, and it reduces substantially the correlations between MCMC draws.

PbBa8.1 and CRb are two clubroot-resistant genes that are important for canola breeding in China. Previously, we combined these resistant genes and developed a pyramid-based, homozygous recurrent inbred line (618R), the results of which showed strong resistance to Plasmodiophora brassicae field isolates, however, the genetic mechanisms of resistance were unclear. In the present work, we conducted comparative RNA sequencing (RNA-Seq) analysis between 618R and its parental lines (305R and 409R) in order to uncover the transcriptomic response of the superior defense mechanisms of 618R and to determine how these two different resistant genes coordinate with each other. Here, we elucidated that the number and expression of differentially expressed genes (DEGs) in 618R are significantly higher than in the parental lines, and PbBa8.1 shares more DEGs and plays a dominant role in the pyramided line. The common DEGs among the lines largely exhibit non-additive expression patterns and enrichment in resistance pathways. Among the enriched pathways, plant&ndash, pathogen interaction, plant hormone signaling transduction, and secondary metabolites are the key observation. However, the expressions of the salicylic acid (SA) signaling pathway and reactive oxygen species (ROS) appear to be crucial regulatory components in defense response. Our findings provide comprehensive transcriptomic insight into understanding the interactions of resistance gene pyramids in single lines and can facilitate the breeding of improved resistance in Brassica napus.

Understanding the diurnal dynamics of surface urban heat islands (SUHIs) is an indispensable step towards their full interpretation at multiple time scales. However, because of the tradeoff between the spatial and temporal resolutions of satellite-derived land surface temperature (LST) data, the climatology, variety, and taxonomy of diurnal SUHI (DSUHI) patterns remain largely unknown for numerous cities with different bioclimates. By combining daily MODIS LST data with a newly developed four-parameter diurnal temperature cycle (DTC) model, we selected 354 Chinese megacities located in different bioclimatic zones to examine the characteristics of the DSUHI descriptors and systematically investigate the prevalent DSUHI temporal patterns. The DSUHI variations demonstrate that both the daily maximum and minimum SUHI intensity (SUHII) can occur during most periods of the day, although these intensities are more likely to occur in the early morning and noon/afternoon. Our results also reveal that both strong SUHIs (SUHII > 3 K) and surface urban cool islands (SUCIs) (SUHII

Summer outbreaks of the hepatobiliary syndrome in fish impose a heavy burden on aquaculture in China. Curcumin is a polyphenol with antioxidant activity that has been used to protect the health of fish livers, but the mechanism underlying its protective effect is unclear. In this study, an in vitro model of hepatocyte oxidative damage in Oreochromis niloticus was established using H2O2. Treatment with 5 mM H2O2 for 2.5 h markedly reduced cell viability and antioxidant activity and elevated lactate dehydrogenase (LDH) activity, indicating conditions that can be used to establish an oxidative stress model. Under H2O2 stress, curcumin pretreatment significantly maintained cell viability, reduced malondialdehyde (MDA) levels, and increased superoxide dismutase (SOD) activity. RNA-seq results showed that acute H2O2 treatment resulted in minor changes in gene expression, whereas curcumin changed the expression profile and affected cytochrome P450 (Cyp 450), glutathione (GSH) metabolism, and the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Several critical antioxidant defense signaling pathways were identified, and altered expression was confirmed by q-PCR. These results indicate that curcumin might upregulate PPAR expression by increasing Cyp2J2 expression. Further experiments showed that curcumin can upregulate the Nrf2-Keap1 signaling pathway at the transcriptional level, and this upregulation can induce downstream defense genes, including glutamate cysteine ligase catalytic subunit(GCLC) and glutamate cysteine ligase modifier subunit (GCLM), and thereby promote GSH synthesis and the expression of related antioxidases. This study might shed light on the effects of curcumin on the prevention and alleviation of liver diseases in fish.

Supramolecular nanofibers based on D-amino acid-containing peptide self-assembly have attracted increased interest recently because of their superior biostability. However, the construction of nanostructures containing D-amino acids is still insufficient at present, and their application in biomedical fields should be further explored. Herein, we demonstrated that the aggregation property of hydrophobic anticancer tyroservaltide (YSV) could be decreased by introducing D-amino acids. Using such strategy, we fabricated a novel anticancer hydrogelator based on the D/L-peptide of NapGDFDFDYGYSV (D-YSV). Through a heating-cooling process, NapGDFDFDYGYSV self-assembled into a stable hydrogel, while its control peptide of NapGFFYGYSV (L-YSV) self-assembled into an unstable suspension. The nanofiber of D-YSV exhibited an excellent resistance to proteinase digestion comparing with that of L-YSV, and a better anticancer efficiency in vitro due to its improved cellular uptake. Moreover, D-YSV possessed good biocompatibility and showed a prominent tumour inhibition capacity in vivo via tail vein injection. Our study demonstrates a powerful strategy to reduce the aggregation property and construct supramolecular hydrogels of bioactive hydrophobic L-peptides.

Complete urban surface temperature ( T c ) is a key variable for quantifying the urban surface - atmosphere interactions. The estimation of T c usually requires detailed knowledge of surface geometry and facet temperatures, which are difficult to obtain by remote sensing. Therefore, simple but efficient strategies for the remote estimation of T c are currently lacking. Facing this challenge, we proposed a comprehensive solution to estimate T c remotely using only the directional radiometric temperatures (DRTs) without the assistance of ground-based information. By comparing T c with the nadir temperature (T0), DRTs within the entire hemisphere, and solid-angle integral temperature (SIT), we obtain the following results: (1) The optimal viewing azimuth and zenith angles at which the DRTs are the closest to T c are φs±90° (φs is the solar azimuth angle) and 45–60°, respectively. (2) The estimation of Tc could be further improved once the DRTs from all-direction are available, and the MAE for the SIT that most closely approximated T c is only 0.87 K. (3) The MAE of the SIT that best approximates T c by combining only four DRTs and a kernel-driven model is only slightly higher than that of the specific SIT based on the original DRTs, indicating that the remote estimation of T c using limited DRTs is plausible. These proposed strategies are generally simple and effective, and can help facilitate the estimation of T c and therefore help advance the thermal remote sensing of urban climate and environment.

The need for renewable bioenergy sources has renewed interest in lignin chemistry; however, structural elucidation and characterization of lignin degradation products remain a challenge because of lack of effective analytical methods. The analysis of lignin oligomers has been accomplished by simple deprotonation of weakly acidic phenolic moieties using NaOH and analyzed in a negative ESI mass spectrometry. Although simple deprotonation works to produce excellent results for many types of lignin compounds, others can undergo extensive in-source fragmentation for certain bond types making structural elucidation more complicated. Herein, we present an alternative method for analyzing lignin model compounds using chloride adduct chemistry. In this study, nine β-O-4 dimers, an (4-Ο-α)(β-Ο-4) trimer, and a (β-O-4)(β-O-4) trimer were synthesized and analyzed using chloride adduct mass spectrometry in the negative mode using NH4Cl as the chloride source. Stable chloride adducted molecular ions were observed for a...

Platinum plays a central role in a variety of electrochemical devices and its practical use depends on the prevention of electrode degradation. However, understanding the underlying atomic processes under conditions of repeated oxidation and reduction inducing irreversible surface structure changes has proved challenging. Here, we examine the correlation between the evolution of the electrochemical signal of Pt(111) and its surface roughening by simultaneously performing cyclic voltammetry and in situ electrochemical scanning tunnelling microscopy (EC-STM). We identify a ‘nucleation and early growth’ regime of nanoisland formation, and a ‘late growth’ regime after island coalescence, which continues up to at least 170 cycles. The correlation analysis shows that each step site that is created in the ‘late growth’ regime contributes equally strongly to both the electrochemical and the roughness evolution. In contrast, in the ‘nucleation and early growth’ regime, created step sites contribute to the roughness, but not to the electrochemical signal. Understanding the structural stability of platinum surfaces upon oxidation and reduction conditions has proved challenging. A correlation of surface site formation to nanoisland growth in the electrochemical roughening of Pt(111) is now identified.

The rediscovery of black phosphorus (BP) has expanded the 2D family into Group 15 (Nitrogen Group) elements, among which bismuthene is the latest member with extraordinary opto-electronic, catalytic and biocompatible properties and potential as a 2D topological insulator. However, bulk Bi is not easily mechanically exfoliated as its counterpart of BP. Thus, to date, the reports on 2D Bi fabrication are rare, and investigations on its nonlinear optical properties are even less. Herein, we rationally designed a new strategy combining acid-interaction and liquid exfoliation to successfully transform metal bulk Bi into few-layer semiconductor, which resulted in unseen opto-electronic properties, such as tunable nonlinear responses all the way to the near-infrared (NIR) region. This band is critical for telecommunication and military purposes, but currently, functioning materials are extremely scarce. The origin of this strong saturable absorption was thoroughly explored through time-resolved spectroscopy spanning from the fs to μs timescale, which indicated ultrafast fs to ps carrier dynamics in the early stage and long exciton bleaching recovery up to μs. As a proof-of-concept application, the as-prepared 2D Bi was employed as a saturable absorber to mode-lock a Tm-doped fiber laser and successfully realized a 2 μm NIR-wavelength output. This study not only offers an effective and scalable method to fabricate the new 2D family member bismuthene with extraordinary stability, but also explores its strong and broad nonlinear responses extending into the NIR region and fundamental photoinduced dynamics, which demonstrate the full potential of 2D Bi for application in opto-electronic devices and nonlinear optics.

Parametric kernel-driven models are crucial for operationally adjusting satellite-derived urban land surface temperatures (LSTs) obtained at slant angles to hemispherically-representative values. Various parametric models have been proposed to simulate urban thermal radiation directionality, but a comprehensive comparison of the performances of the published parametric models, especially over a variety of urban surfaces under different solar radiation conditions, remains lacking. It is also unknown whether the combination of the available hotspot and base shape kernels can be used to derive new parametric models with even better performances compared with existing models. Based on both forward-modelling and satellite datasets, here we systematically evaluate three single-kernel and eight dual-kernel parametric models. The main findings are as follows: (1) Amongst the three single-kernel models, the VIN model has the best overall performance, with an average root-mean-square error (RMSE) of 0.79 and 1.35 K, based on forward-modelling and satellite data, respectively. However, the ROU and RL models outperform the VIN model when the solar zenith angle is less than 30°, and in particular it has a higher accuracy for hotspot description. (2) The dual-kernel models usually perform better than the single-kernel models. Amongst the eight dual-kernel models, those with the hotspot kernel KHotspot_rou (used by the ROU model) are more competent than those using KHotspot_vin (obtained from the Vinnikov model) as the hotspot kernel. The RVI model, in general, has the highest accuracy, with average RMSEs of 0.49 and 0.77 K based on forward-modelling and satellite data, respectively. (3) Compared with the single- and dual-kernel models, the multi-kernel models sometimes have better accuracies but the performance improvements are relatively limited. We also provide recommendations for model selection under various scenarios. Our systematic assessment improves our understanding of urban thermal radiation directionality regimes and potentially enables the improved correction of remotely-sensed urban LSTs, thus helping to advance thermal remote sensing of the urban environment.

Curcumin is a polyphenol with antioxidant activity that has been used to protect the health of fish livers. Our previous studies about comparative transcriptome have shown that curcumin can enhance the Nrf2-Keap1 signaling pathway and induce downstream anti-stress genes to maintain cell viability. However, the possible role of miRNAs in the protective mechanism of curcumin is not understood. In this study, the tilapia hepatocyte H2O2 stress model was used, and the miRNA expression profile for four groups (control group, curcumin group, H2O2 group, and protection group) were established by high-throughput sequencing. In our results, 278–333 types of Oreochromis niloticus miRNAs, 309–543 types of conserved miRNAs, and 535–746 types of novel miRNAs were identified in different samples. Differentially expressed miRNAs were identified by comparing miRNA expression profiles among the four groups. The expression levels were confirmed by q-PCR. The target genes of these differentially expressed miRNAs were predicted, and their functional annotations were enriched by GO and KEGG analysis, which revealed that many target genes were involved in “response to stimulus” and “antioxidant activity” in each pair of groups. Several miRNAs related to oxidative stress showed differential expression. For example, in the H2O2 group, the expression of miR-122 was decreased, and the expression of miR-21 and miR-489 increased significantly. In the curcumin group, the expression of miR-153b was decreased, and the expression of miR-200a and miR-29 was increased significantly. miR-153b, miR-200a, and miR-29 may be involved in the regulation of the Nrf2-Keap1 signaling pathway by curcumin. This work might provide insights into the molecular mechanisms of miRNA regulation of curcumin on the prevention and alleviation of liver diseases in fish.

Removing long-chain ligands on the surface of perovskite nanocrystals (NCs) is a promising strategy to facilitate charge transport towards a high-performance perovskite light-emitting diode (PeLED). However, perovskite NCs, especially CsPbI3 NCs, tend to decompose in the ligand removal procedure due to their poor stability of perovskite NCs and high polarity of solvents. Here, we report Sr2+-doped CsPbI3 NCs that were synthesized by a modified hot injection method. These NCs show enhanced stability and near-unity photoluminescence quantum yield (PLQY, 99.8%). More importantly, the CsPbI3:Sr2+ NCs still maintain a high PLQY (97.5%) after removing surface ligands by a polar solvent (ethyl acetate, EA). Furthermore, a mixture of EA and octane was used to prepare smooth and dense CsPbI3:Sr2+ NC films with an exceedingly high PLQY of 73.2% and a high stability under ambient conditions. Finally, the red-emitting CsPbI3:1.8% Sr2+ PeLEDs demonstrate a world-record peak external quantum efficiency (EQE) of 17.1%.

Understanding the dynamics and spatial heterogeneity of the intra-city surface heat island (herein termed the surface urban heat island, SUHI) is critical for the design of urban heat mitigation strategies. Large disparities in the spatiotemporal variations of SUHIs are anticipated under different urbanization processes. However, most previous studies have focused solely on the inter-annual spatiotemporal SUHI variations of regular urbanization, while those for stable- and counter-urbanization remain largely unknown. Based on the remote identification of these three urbanization types over Guangzhou, China, we propose a novel strategy to investigate simultaneously the spatiotemporal variations and the associated controls of SUHIs. Our results indicate that: (1) Counter-, regular-, and stable-urbanization occurs mainly over the city center, city periphery, and the in-between areas, respectively. (2) The three urbanization types all demonstrate similar and significant growth in the daytime local SUHI intensity (SUHII). (3) There are significant disparities in the contributions of controls to the inter-annual daytime SUHII trends for these three urbanization processes. For the regular urbanization, the increase of the impervious surface percentage (ISP) dominates daytime SUHII growth, while the combination of ISP and residual factors (e.g., background climate and 3D urban geometry) leads for counter urbanization. For stable urbanization, the combination of residual controls and the increase in population density is the major factor. Urban divisional management may contribute to the mitigation of intra-city SUHI. Our findings potentially advance our understanding of changes in urban thermal environment under different urbanization processes.

Returning maize residue not only helps maintain soil fertility but also local soil carbon balance. Although there have studies of maize residue decomposition, seldom focused on combining different parts of maize residue under field and incubation experiments at different temperatures in saline and alkaline soils. We carried out an incubated decomposition experiment of maize residue (15, 25, 35℃) and a field experiment (12 ~ 29℃) by litter bag method within 90 days in a Solonchak. A double exponential model was used to simulate labile C (carbon) and recalcitrant C in decomposition. The correlation showed a closed decomposition relationship (R2 > 0.98) for double exponential model. Field and laboratory experiments showed decomposition increased with temperature and followed order leaf (35%~73%) > stem (35%~72%) > root (21%~63%). The decomposition increased rapidly within first 15 days and then slowed. The decomposition rates (day−1) of maize residue were 0.10 ~ 0.16 (labile C) and 0.0005 ~ 0.0015 (recalcitrant C) at field, and 0.05 ~ 0.10 and 0.0001 ~ 0.0014 at lab. The decomposition rate (day−1) of native soil organic C (SOC) labile C (0.05 ~ 0.13) and recalcitrant C (0.0002 ~ 0.0005) changed with temperature, but recalcitrant C changed not (0.98). The decomposition rate of recalcitrant C increased by 180%~1100%, which was higher than that of labile C (50%~80%) with increasing temperature. The Q10 value showed decomposition of maize residue and SOC at 15 ~ 25 °C was larger than that at 25 ~ 35 °C. By adding 1 g maize stem or leaf to field, 0.15 ~ 0.39 g or 0.18 ~ 0.33 g C stored in soil, respectively. In summary, increased temperature significantly accelerated maize residue decomposition by increasing decomposition rate and turning a part of recalcitrant C into labile C. The temperature sensitivity of maize residue and SOC decomposition was higher at 15 ~ 25 °C than at 25 ~ 35 °C. The simulated saline and alkaline soil C stock was 0.1 ~ 1.7 kg ha−1 yr−1 from maize stem and leaf return facing warming.

Disaggregation of land surface temperature (DLST), the aim of which is to generate LSTs with fine resolution, has been attracting increasing attention since the 1980s. The past three decades have been witness to the emergence of DLST methods in large numbers, the accuracies of which were often assessed by comparing the disaggregated with fine spatial resolution LSTs using error indexes such as the root mean square error (RMSE). However, the majority of previous error indexes are, by their nature, insufficient for assessing the performances of DLST methods. This insufficiency is due in part to their lower competence at distinguishing the DLST error from LST retrieval errors and in part to their inability to remove the process controls resulting from different thermal contrasts, temperature units, and resolution ratios among different scenarios in which DLST is conducted. This is also because they are unable to denote the sharpening statuses of the DLST results (e.g., under- or over-sharpening). This status quo has made the evaluation of method performances challenging and sometimes unreliable. To better assess DLST method performances under diversified scenarios, we formulated five protocols, through which a simple yet flexible index (SIFI) was subsequently designed. The establishment of an SIFI includes the following four steps: (1) a detail-based evaluation, which is designed primarily to exclude the impacts of systematic deviations on estimated LSTs; (2) a Gaussian normalization, which is primarily intended to remove the differences in temperature units and thermal contrasts; (3) a triple comparison, with the aim of attenuating the influence of the difference in the resolution ratio in comparisons of method performances; and (4) a piecewise comparison, which is primarily scheduled to distinguish among the three sharpening statuses, under-sharpening, acceptable over-sharpening, and unacceptable over-sharpening. The evaluation ability of SIFI was compared with those of the RMSE, Erreur Relative Globale Adimensionnelle de Synthese (ERGAS), and image quality index (Q) using simulation tests and actual thermal data. The results illustrate that SIFI generally outperforms the other indexes; it is able to mitigate the impacts from process errors and controls during evaluation and is able to indicate the sharpening statuses accurately. We believe this new index will likely promote the design of future DLST algorithms and procedures.