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Abstract Realizing efficient energy utilization from the heat source of the sun and the cold source of outer space is of great significance for addressing the global energy and environmental crisis. Materials with ideal full‐spectrum solar absorption and infrared emission are highly desirable for adapting to the continuous weather dynamic throughout the day, nonetheless, their development remains challenging. Here, a polymer nanocomposite with full‐spectrum strong solar (280–2500 nm) absorption ranging from 88.8% to 94.8% with an average value of 93.2% and full‐spectrum high infrared (8–13 µm) emission ranging from 81.3% to 90.0% with an average value of 84.2%, is reported by melt‐processing polypropylene and uniformly dispersed low‐loading MXene nanosheets (1.9 vol%). The nanocomposite can achieve daytime photothermal enhancement of ≈50 °C and nighttime radiative cooling of 8 °C. The temperature difference throughout the day ensures all‐day uninterrupted thermoelectric generation, yielding a power density output of 1.5 W m−2 (daytime) and 7.9 mW m−2 (nighttime) in real outdoor environment without any additional energy consumption. This work provides an impressive polymer nanocomposite with ideal full‐spectrum solar absorption and infrared emission for all‐day uninterrupted thermal energy management and conversion.

Abstract Smart windows with light management and indoor solar heating modulation capacities are of paramount importance for building energy conservation. Thermochromic poly(N‐isopropylacrylamide) (PNIPAm) hydrogel smart windows exhibit advantages of the relatively suitable transition temperature of 32 °C, high cost‐effective and automatic passive sunlight regulation, but sustain slow response rate and unsatisfactory solar modulation efficiency. Herein, a strategy of one‐step copolymerization of NIPAm and different olefine acids (OA) using reverse atom transfer radical polymerization method is developed to fabricate various chain/microparticle hybrids (CMH) for liquid energy‐saving windows. Synergetic mechanisms of thermal‐induced dissolution and aggregation of linear polymer chains integrated with water capture and release of microgel particles contribute to tunable light‐scattering behaviors and adaptive solar modulation. Without any post‐treatment, the as‐prepared poly(N‐isopropylacrylamide‐co‐acrylic acid) (P(NIPAm‐co‐AA))‐based CMH suspension is injected into sandwich glass to construct energy‐saving windows, which exhibits appreciated near‐room‐temperature transition (26.7 °C), rapid response (5 s), extraordinary luminous transmittance (91.5%), and solar modulation efficiency (85.8%), resulting in a substantial decline of indoor temperature of 24.5 °C in simulation experiment. Combining the versatile strategy with flexible adjustment on transition temperature, multifarious P(NIPAm‐co‐OA)‐based CMH windows with eminent light management capacity are obtained. This work will powerfully promote the development and renovation of energy‐efficient windows.

Biodegradable plastics are attracting attention as a solution to the problems caused by plastic waste. Among biodegradable plastics, polylactide (PLA) and poly (butylene succinate) (PBS) are particularly noteworthy because of their excellent biodegradability. However, the drawbacks of their mechanical properties prompts the need to compound them to achieve the desired strength. The characteristics of the interface of the composite material determine the realization of its final performance. The study of the interface and microstructure of composites is essential for the development of products from degradable polymers. The morphology evolution and microcrystal structure of spin-casted fully biodegradable (PLA/PBS) blend films were investigated using atomic force microscopy (AFM)-based nanomechanical mapping. Results show that intact blend films present an obvious phase separation, where the PBS phase is uniformly dispersed in the PLA phase in the form of pores. Furthermore, the size and number of the PBS phase have a power exponential relationship and linear relationship with PBS loading, respectively. Intriguingly, after annealing at 80 °C for 30 min, the PLA phase formed an orderly petal-like microcrystalline structure centered on the PBS phase. Moreover, the microcrystalline morphology changed from a “daisy type” to a “sunflower type” with the increased size of the PBS phase. Since the size of the PBS phase is controllable, a new method for preparing microscopic patterns using fully biodegradable polymers is proposed.

Herein, a new magnetic super-tough polypropylene (PP) composite was developed via one-step melt blending with maleic anhydride grafted ethylene-octene copolymer (POE-g-MAH) and reactive nano-Fe3O4. The reactive nano-Fe3O4 with polyamide (PA) tails (PA-Fe3O4) was prepared by in situ ring-opening polymerization PA with amino-modified Fe3O4. By regulating the ratio of POE-g-MAH to PA-Fe3O4, PA-Fe3O4 nanoparticles can selectively and uniformly distribute in the POE-g-MAH phase, reinforcing the POE-g-MAH phase and reducing its processing viscosity synchronously as a new plasticizer and compatibilizer. Meanwhile, a cocontinuous morphology was formed in the PP/POE-g-MAH/PA-Fe3O4 composite at a low elastomer content, contributing to the dramatically enhanced toughness of the PP matrix without deteriorating the processing flowability. In particular, adding 4 wt% PA-Fe3O4 into PP/POE-g-MAH (weight ratio: 80/20), the notched Izod impact strength of the composite reached 74.2 kJ/m2, which was enhanced by approximately 247%. In addition, these super-tough PP composites have excellent flexibility and room temperature soft magnetic performance. This study provides a novel and feasible strategy to fabricate magnetic polymer composites with excellent mechanical properties via manipulating the morphology of the composites.

Study area: Northeast China Plain (NECP) and North China Plain (NCP). Study focus: Groundwater resources in the northern plains of China are the primary source of domestic and irrigation water, and long-term overexploitation may cause groundwater depletion and deterioration in these plains. In this study, based on observations of groundwater depth (i.e., the depth of phreatic water below the land surface) from 2000 to 2019 in the NECP and NCP, the spatial distribution characteristics and long-range correlation (LRC) of the regional groundwater depth are analyzed using the geostatistical method and fractal theory. New hydrological insights: In terms of the spatial distribution of groundwater depth, an overall trend of decline and then recovery from 2000 to 2019 can be observed in the NECP, indicating that the persistent decline of groundwater depth is not conspicuous, while there is a persistent decline of groundwater depth in the NCP. Regarding the LRC of groundwater depth, the Hurst exponents calculated using the R/S analysis demonstrate the persistence of groundwater depth variation in the NECP and positive persistence of groundwater depth decline in the NCP. The Hurst exponent reveals that the groundwater depth in the NECP will likely remain stable in the future, while the groundwater depth in most areas of the NCP may continue to decline if the dominant factors remain unchanged. Moreover, the dynamic change in the groundwater depth of the NECP may be mainly affected by natural structural factors, while anthropogenic factors may trigger that response in the NCP.

This study aims to investigate the effects of CLAUDIN-6 (CLDN6) on cell apoptosis and proliferation of bovine cumulus cells (CCs). Immunofluorescence staining was used to localize CLDN6 protein in CCs. Three pairs of siRNA targeting CLDN6 and one pair of siRNA universal negative sequence as control were transfected into bovine CCs. Then, the effective siRNA was screened by real-time quantitative PCR (RT-qPCR) and Western blotting. The mRNA expression levels of apoptosis related genes (CASPASE-3, BAX and BCL-2) and proliferation related genes (PCNA, CDC42 and CCND2) were evaluated by RT-qPCR in CCs with CLDN6 knockdown. Cell proliferation, apoptosis and cell cycle were detected by flow cytometry with CCK-8 staining, Annexin V-FITC staining and propidium iodide staining, respectively. Results showed that the CLDN6 gene was expressed in bovine CCs and the protein was localized in cell membranes and cytoplasms. After CLDN6 was knocked down in CCs, the cell apoptosis rate significantly decreased and the pro-apoptotic genes BAX and CASPASE-3 were down-regulated significantly, whereas the anti-apoptotic gene BCL-2 was markedly up-regulated (p < 0.05). Additionally, CLDN6 knockdown significantly enhanced cell proliferation of CCs at 72 h after siRNA transfection. The mRNA levels of proliferation-related genes PCNA, CCND2 and CDC42 increased obviously in CCs with CLDN6 knockdown (p < 0.05). After CLDN6 was down-regulated, the percentage of CCs at S phase was significantly increased (p < 0.05). However, there was no remarkable difference in the percentages of cells at the G0/G1 phase and G2/M phase between CCs with or without CLDN6 knockdown (p > 0.05). Therefore, the expression of CLDN6 and its effects on cell proliferation, apoptosis and cell cycle of bovine CCs were first studied. CLDN6 low expression inhibited cell apoptosis, induced cell proliferation and cell cycle arrest of bovine CCs.

In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (φ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 °C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.

Poly(lactic) acid (PLA) is one of the most promising biobased materials, but its inherent flammability limits its applications. A novel flame retardant hexa-(DOPO-hydroxymethylphenoxy-dihydroxybiphenyl)-cyclotriphosphazene (HABP-DOPO) for PLA was prepared by bonding 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO) to cyclotriphosphazene. The morphologies, mechanical properties, thermal stability and burning behaviors of PLA/HABP-DOPO blends were investigated using a scanning electron microscope (SEM), a universal mechanical testing machine, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limiting oxygen index (LOI), vertical burning (UL-94) and a cone calorimeter test (CCT). The LOI value reached 28.5% and UL-94 could pass V-0 for the PLA blend containing 25 wt% HABP-DOPO. A significant improvement in fire retardant performance was observed for PLA/HABP-DOPO blends. PLA/HABP-DOPO blends exhibited balanced mechanical properties. The flame retardant mechanism of PLA/HABP-DOPO blends was evaluated.

An efficient catalytic system was developed for the acetalization and ketalization of carbonyl compounds with polyhydric alcohols under mild solvent-free conditions. In the presence of 0.1 mol% CoCl2 and 0.2 mol% dimethylglyoxime at 70 °C under 5 KPa pressure for 1 h, 95.3% conversion of cyclohexanone and 100% selectivity of the corresponding cyclic ketal could be obtained, where TOF reached as high as 953 h−1. It is proposed that the in situ generated planartetracoordinate cobaloxime played the key role in the catalytic cycle and was responsible for the excellent catalytic performance.

The rheological behavior of a reactive blend system of nylon1212 with maleic anhydride grafted poly(ethylene-octene) was studied in correlating with the key mechanical parameters. Results illustrated that the "gel points" acquired from the dynamic rheological data and the "supertoughness points" of the blends have a corresponding relationship. Thus, just by simple composition designs and a small amount of samples, the super-toughness point could be conveniently determined by the dynamic rheological measurements. Furthermore, special "double network" morphology at the gel point was directly observed for the first time and the new mechanism of super-toughness has also been discussed. [ABSTRACT FROM AUTHOR]

Understanding a neuron's transfer function, which relates a neuron's inputs to its outputs, is essential for understanding the computational role of single neurons. Recently, statistical models, based on point processes and using generalized linear model (GLM) technology, have been widely applied to predict dynamic neuronal transfer functions. However, the standard version of these models fails to capture important features of neural activity, such as responses to stimuli that elicit highly reliable trial-to-trial spiking. Here, we consider a generalization of the usual GLM that incorporates nonlinearity by modeling reliable and nonreliable spikes as being generated by distinct stimulus features. We develop and apply these models to spike trains from olfactory bulb mitral cells recorded in vitro. We find that spike generation in these neurons is better modeled when reliable and unreliable spikes are considered separately and that this effect is most pronounced for neurons with a large number of both reliable and unreliable spikes. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor about the rheological behavior and morphology of nylon/elastomer blends.

Uniform monodisperse nanospheres of tetra-kis(4-methoxylphenyl) porphynatemanganese (III) chloride [MnIII(TMOPP)Cl] of about 200 nm have been synthesized through a facile surfactant-assisted reprecipitation method at room temperature. Scanning electron microscopy, transmission electron microscope, infrared spectrum, ultraviolet-visible spectrum, and elemental analysis were adopted to characterize the as-prepared metalloporphyrin nanostructures. The influence factors in the reaction to the sizes and morphologies of porphyrin nanoparticles were discussed. The sizes of porphyrin nanoparticles were affected mainly by the porphyrin concentration and only monodisperse nanoshperes with high uniformity in sizes and shapes can self-assemble to form order two-dimensional superstructures. [ABSTRACT FROM AUTHOR]