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•A biomimetic gelatin/chitosan/polyvinyl alcohol/nano-hydroxyapatite scaffold was synthesized.•The effect of polyvinyl alcohol contents on the composite scaffolds was evaluated.•The ...composite scaffolds showed positive effects on osteogenic differentiation.•The composite scaffolds could mimic the structure and function of natural bone.
Multi-component bone tissue engineering scaffolds are the dominant trend to address complex requirements of bone defect repair. In this study, to mimic component and microstructure of natural bone, polymers (natural and synthetic) and nano-hydroxyapatite (nHAp) were fabricated to form a porous composite scaffold. Gelatin (Gel), chitosan (CS) and polyvinyl alcohol (PVA) were first assembled to simulate extracellular matrix. The simulated matrix exhibited tunable pore size, porosity, swelling, pH, degradation and mechanical strength. After the incorporation of nHAp, the composite scaffolds showed improved compression resistance, pH adaptability, improved surface bioactivity and biomimetic structure. In addition, the composite scaffolds can effectively promote cell proliferation and adhesion, of which, scaffolds containing 12.5% of nHAp were demonstrated to have high osteogenic differentiation ability. Hence, these results suggest that Gel/CS/PVA/nHAp composite scaffolds could be a promising biomimetic scaffold for bone tissue engineering.
•Hyperspectral imagery is applied to quantify Cl− concentration in the mortar.•Hyperspectral reflectance indicator is used to predict Cl− induced rebar corrosion.•The reflectance intensity at ...wavelength 2258 nm linearly increased with Cl− content.
In this study, a new method is proposed to determine chloride ion (Cl−) concentration and steel rebar corrosion from hyperspectral spectroscopy. Three groups of mortar cubes with water-to-cement (w/c) ratios of 0.5, 0.6, and 0.7 were subjected to rapid corrosion testing in 3.5 wt% NaCl solution to accelerate the transport of chloride ions. Embedded along the centerline of each mortar cube was a steel rebar that corroded when the Cl− accumulation around it exceeded a critical/threshold concentration. Open circuit potential was measured to characterize the corrosion possibility of steel rebar. Mortar surfaces were scanned with a hyperspectral camera in the infrared range (1000 nm − 2400 nm), and the reflectance intensity at 2258 nm wavelength was extracted to characterize Friedel’s salt. The possibility of steel corrosion was experimentally shown to increase with the characteristic reflectance intensity that in turn decreases linearly with the diffusion depth at a given corrosion state. For each type of mortar cubes with a constant w/c ratio, the characteristic reflectance intensity linearly increases with the Cl− content up to 0.8 wt%. Therefore, the corrosion status of steel rebar and Cl− concentration can be predicted based on the combined information from the reflectance intensity on the mortar surface and the relation between reflectance and total chloride content.
The East Asian summer monsoon (EASM) is essential for the livelihoods of billions of people in East and Southeast Asia. Its present features and evolution history of the Quaternary have been well ...studied, yet how did EASM operate in much older geological times, especially before the late Miocene, is relatively less constrained. Scientific drillings conducted in the South China Sea (SCS) offer excellent opportunities to resolve this issue to a certain extent considering the EASM has been prevailing in this area since at least the earliest Miocene. In this study, mineralogical and stratigraphic studies were carried out on the middle Miocene pelagic reddish clay recovered at International Ocean Discovery Program Site U1433 using clay mineralogical and natural gamma radiation data. Our results show that the smectite content and illite crystallinity of the deep SCS clay were direct consequences of the EASM intensity varying in precession rhythm and modulated by eccentricity cycles. A high-resolution temporal framework constructed with onboard age controls and cyclostratigraphic analyses demonstrates that the pelagic reddish clay from Site U1433 was accumulated from 17.17 to 12.69 Ma. During this period, deep-sea sedimentation of the SCS was controlled by the EASM and influenced by the sea-level change. Importantly, clay mineral is proved to be an efficient terrigenous standard of astronomical tuning and stratigraphic correlation for pelagic sediments. It is also verified that the EASM intensified during the Miocene Climatic Optimum and the following Middle Miocene Climate Transition, and induced higher humidity and seasonality, respectively. Then, the EASM gradually weakened since the expansion of the East Antarctic Ice Sheet.
•A standard process for building age models of pelagic sediments is proposed.•The first high-resolution middle Miocene time framework in the deep South China Sea.•Pelagic clay minerals recorded the Miocene East Asian summer monsoon evolution.•Continental shelves buffered the middle Miocene sedimentation in the deep sea.•The South China Sea's reddish clay composition is homogeneous in the oceanic basin.
The in-plane seismic behavior of unreinforced masonry (URM) structures is closely related to the aspect ratio of the wall and vertical load. The purpose of this study was to investigate the ...difference between the failure mode of the model and the horizontal load using the finite element model (FEM) under the action of aspect ratio (0.50 to 2.00) and vertical load (0.2 MPa to 0.70 MPa). The overall macro model was established using the Abaqus software, and the corresponding simulation was performed. The simulation results indicate that: i) the shear failure and flexural failure were the main failure modes of masonry walls; ii) shear failure could be viewed as the main failure mode of the model when the aspect ratio was less than 1.00; however, the flexural failure was considered to be the main failure mode of the model once the aspect ratio was greater than 1.00; iii) when a vertical load of 0.20 MPa was applied to the model, only flexural failure was observed, regardless of whether the aspect ratio of the model increased or decreased; the flexural shear mixed failure was captured within the range of 0.30 MPa- 0.50 MPa; the shear failure was the main failure mode within the range of 0.60 MPa- 0.70 MPa; and iv) the wall with an aspect ratio less than 1.00 could bear a higher horizontal load, and the increase in vertical load can significantly improve the horizontal load of the wall. In contrast, once the aspect ratio of the wall reaches or exceeds 1.00, the increase in the vertical load has little effect on the increase in the horizontal load of the wall.
A synaptic memristor based on IGZO and oxygen-deficient HfO2 films has been demonstrated. The memristor exhibits a fatigue response to a monotonic stimulus of voltage pulses, which is analogous to ...the habituation behavior of biological memory. The occurrence of habituation is nearly simultaneous with the transition from short-term memory to long-term memory. The movement and redistribution of oxygen species with the assistance of polarization in HfO2 layer are responsible for the above results. The observation of habituation behavior proves the potential prospect of memristor on the mimic of biological neuron.
MCL1 is a pivot member of the anti-apoptotic BCL-2 family proteins. While a distinctive feature of MCL1 resides in its efficient ubiquitination and destruction, the deubiquitinase USP9X has been ...implicated in the preservation of MCL1 expression by removing the polyubiquitin chains. Here we perform an unbiased siRNA screen and identify that the second deubiquitinase, USP13, regulates MCL1 stability in lung and ovarian cancer cells. Mechanistically, USP13 interacts with and stabilizes MCL1 via deubiquitination. As a result, USP13 depletion using CRISPR/Cas9 nuclease system inhibits tumor growth in xenografted nude mice. We further report that genetic or pharmacological inhibition of USP13 considerably reduces MCL1 protein abundance and significantly increases tumor cell sensitivity to BH3 mimetic inhibitors targeting BCL-2 and BCL-XL. Collectively, we nominate USP13 as a novel deubiquitinase which regulates MCL1 turnover in diverse solid tumors and propose that USP13 may be a potential therapeutic target for the treatment of various malignancies.
•Time-resolved rotational and vibrational temperatures in spark plasma are measured.•These plasma temperatures are related to the energy release rates to the plug gap.•The plasma is in the ...non-thermal equilibrium state during the discharge processes.•Continuous discharge generate a stable long-time non-thermal equilibrium plasma.
Increasing discharge energies and employing advanced discharge strategies have been deemed to be effective methods for improving the ignition processes, especially for diluted or lean combustion. However, so far knowledge on the relevant mechanism is far from adequate. In particular, the effects of the plasma produced between the spark plug electrodes on spark ignition processes need to be further clarified. The plasma temperatures are important as they are closely related to the chemical reaction rate. In this study, the vibrational and rotational temperatures of the discharge plasma are quantitatively evaluated by a time series of spectral measurements with different discharge energies and strategies in air under atmospheric pressure, based on the N2 second positive molecular emission spectra. The vibrational and rotational temperatures show a perfect consistent trend with the release rates of delivered energy to the spark plug gap. This indicates that the two temperatures can be enhanced by the higher energy release rates and can be effectively controlled by different discharge strategies. The vibrational and rotational temperatures measured in this study are in the range of 3700–4300 K and 1400–2600 K, respectively. The temperature differences between the vibrational and rotational temperatures exceed 1600 K, increasing with the energy release rate decreasing. This indicates that the spark discharge plasma is in a state of non-thermal equilibrium with the existence of the discharge energies under the non-flow conditions. These results would be a reference to further develop the advanced discharge strategies and improve the ignition stability.
In this study, we present a regional insight into characteristics and formation process of the widespread extreme haze pollution in northern China during January of 2013 using integrated satellite ...observations and ground measurements. Different from common regional pollution, dense haze clouds during the most polluted period not only wandered over northern China for more than one week, but also exhibited large spatial variations with some abrupt peak values in Beijing. High UV Aerosol Index (UVAI) values >2.5 indicate prevalent absorbing aerosols in upper part of the haze clouds. CALIPSO vertical detection shows that the haze layers were more than 3 km thick, with strong extinction within 1 km near surface and elevated dust layers above. Top of the more than 2 km thick dust plumes can reach 5 km, having a substantial contribution to the haze clouds. Movement of high aerosol loading regions with aerosol optical depth (AOD) exceeding 2.0 shows a notable superposition of different pollution processes within boundary layer, which largely enhanced the haze pollution. Peak value of PM10 in industrial cities of Hebei was around 1000 μg/m3, almost twice of that in usual pollution. Subsequent peak values of PM10 from south to north confirm the intense regional transport, which could be the main cause of sudden record-breaking particle concentration in Beijing. Anomalous weather conditions facilitated the unusual heavy pollution became extremely severe. Our results indicate close connections between variation of atmospheric circulation and the regional heavy pollution over northern China.
•Regional insight into widespread extreme haze pollution over eastern China.•Abrupt peak values in Beijing could be caused by regional transport.•The extreme pollution was a special event caused by anomalous weather condition.•Close connections exist between regional air pollution and atmospheric circulation.
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