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We used a transparent systematic review framework based on best practices for evaluating study quality and integrating evidence to conduct a review of the available epidemiology studies evaluating associations between long-term exposure to ambient concentrations of PM2.5 and mortality (all-cause and non-accidental) conducted in North America. We found that while there is some consistency across studies for reporting positive associations, these associations are weak and several important methodological issues have led to uncertainties with regard to the evidence from these studies, including potential confounding by measured and unmeasured factors, exposue measurement error, and model misspecification. These uncertainties provide a plausible, alternative explanation to causality for the weakly positive findings across studies. Using a causality framework that incorporates best practices for making causal determinations, we concluded that the evidence for a causal relationship between long-term exposure to ambient PM2.5 concentrations and mortality from these studies is inadequate.

Optical fiber sensor networks (OFSNs) provide powerful tools for large-scale buildings or long-distance sensing, and they can realize distributed or quasi-distributed measurement of temperature, strain, and other physical quantities. This article provides some optical fiber sensor network technologies based on the white light interference technology. We discuss the key issues in the fiber white light interference network, including the topology structure of white light interferometric fiber sensor network, the node connection components, and evaluation of the maximum number of sensors in the network. A final comment about further development prospects of fiber sensor network is presented.

Hierarchical nitrogen-rich porous carbon (HNPC) was prepared by a simple and effective method using standard wheat straw as raw material. The as-synthesized HNPC material was found to possess high specific surface area. Because of its hierarchical porous structure, the HNPC material enables highly efficient lithium-ion transport through the electrolyte to the negative electrode, which shortens the diffusion path of the lithium-ion channel and reduces the internal resistance. The initial reversible capacity of the HNPC battery reaches 792.41 mAh·g−1 with coulombic efficiency of 88.61%. This type of HNPC material provides a potential anode for lithium-ion batteries with high specific capacity.

The ultrasonic annular array transducer usually has a stronger focusing acoustic field than the linear array and matrix transducer with the same number of array elements, and is more suitable for the detection of large thickness and high attenuation components. However, due to the special arrangement of array elements, the focusing beam cannot be deflected and has a large near field, which limits its application in practical detection. The element parameters of annular array transducer are often designed and analyzed according to the 2-D acoustic field model of a linear array transducer. Therefore, the 3-D acoustic field distribution model of the annular array transducer is established, and the influence of the element parameters on its spatial acoustic field focusing characteristics is analyzed. The design criteria of the array element division mode and element size are proposed, which can avoid the generation of high-energy side lobe and grating lobe, and have good axial acoustic field. Then, the influence of excitation aperture on the energy and size of focal spot at different depths is discussed. The dynamic focusing method with variable aperture of annular array is established, and the C-scan detection experiment is carried out on the addictive manufacturing titanium alloy specimen. The detection results show that the variable aperture method has better central amplitude consistency and imaging accuracy for different depth defects, and has better near surface detection ability than the fixed aperture method.

A new and precise control printing method was developed for preparing homogeneous microspheres. Hydroxyapatite-sodium alginate (HA-SA) mixed suspension was used as printing material and CaCl2 solution was used as solidifying liquid to prepared ceramic microspheres by pneumatic extrusion printing technology. By adjusting the positive pressure, dwell time, and hydroxyapatite concentration, the influence of each parameter on the shape of printed microspheres was studied, and the suitable preparation parameters were determined. Then, the microspheres with uniform particle size distribution were successfully prepared in large quantities by selecting appropriate printing parameters. Then, the microspheres were dried and sintered at different temperatures. During the drying and sintering process, the microspheres showed obvious shrinkage, but still keep good sphericity. The phases of sintered microspheres are hydroxyapatite and calcium oxide. The microstructure shows typical hydroxyapatite grain characteristics.

The current study involves fabrication and characterization of HA scaffolds containing different copper (Cu) content by ion exchange and 3D extrusion deposition technique. The fabricated pure HA and Cu-doped scaffolds (Cu–HA) were characterized by mechanical behavior, SEM, EDS, XRD, and FT-IR studies. The results show that the Cu-doped HA scaffolds show stronger compressive strength. In addition, the antibacterial properties and biological properties of these scaffolds were investigated in vitro. The antibacterial test results show that the addition of Cu in the HA scaffolds increased antibacterial activity, and the antibacterial properties of scaffolds significantly increased with the addition of Cu. The biocompatibility test results show that the 15Cu–HA scaffolds treated with 15% CuSO4 curing solution significantly inhibited of cell growth on day 7, while the 5Cu–HA scaffolds treated with 5% CuSO4 curing solution the cells observed good grown state on day 7. The 5Cu–HA scaffolds show stronger mechanical behavior, increased antibacterial properties and lower toxicity rat bone marrow mesenchymal stem cells (BMSCs) on day 7. So, the developed 5Cu–HA scaffolds can be used as a good biomaterial for bone tissue engineering.

We propose a method for low-concentration detection of sodium chloride based on surface plasmon resonance (SPR). A novel prism coupling structure is designed for the sodium chloride concentration sensor, where a TiO2–ZnO composite film and a MoS2–GO hybrid nanosheet are chosen to enhance the surface plasmon resonance based on an Au nanowire array because of their unique properties in metal nanowire arrays and two-dimensional nanomaterials. Using the finite element method, we analyze the thickness of each medium layer for the structure designed in order to obtain the optimum value, so that the sensitivity of the sodium chloride concentration sensor designed is substantially enhanced. The optimum thickness of each medium layer is given, and the sensitivity of the sodium chloride concentration sensor based on the surface plasmon resonance can reach 0.260°/ (g/100 ml) concentration in the detection range of the sodium chloride concentration from zero to 15 g/100 ml. We derive the relationship between the sodium chloride concentration and the surface plasmon resonance angle in the detection range of the sodium chloride concentration.

In this work, the polycaprolactone (PCL) scaffold with specific surface morphology was prepared by cryogenic printing technique. Biocompatible hydroxyapatite (HA) was added to the PCL matrix to enhance the surface properties and bioactivity of the scaffolds. The effects of HA on the mechanical strength and surface morphology were studied systematically. It was found that the extra surface morphology of filament enhanced the exposure of the HA particles, which induced a positive synergistic effect on surface properties. The wettability and bio-mineralization were significantly improved, and the protein adsorption capacity was 4.5 and 3.9 times than the ones of sample with 20%HA and smooth surface, respectively. Rat bone mesenchymal stem cells (rBMSCs) were used as the cell model to evaluate the cellular response to the specific surface of the scaffolds. The results showed that the scaffolds with 20–40% HA and extra surface had better proliferation ratio. The ALP assay also demonstrated that the synergistic effect was beneficial to cell osteogenic differentiation, and the ALP level was significantly higher than that of pure PCL and smooth PCL/HA composite scaffold samples at the 14th day. Therefore, the PCL/HA composite scaffold with extra surface morphology had better potential for bone tissue engineering.

Here, we describe the identification of PARP1/2 as direct binding proteins of andrographolide (Andro) using protein microarray, surface plasmon resonance (SPR), and enzyme activity assays. We then evaluated the proliferation inhibition, apoptosis, and cell migration effects of Andro on the MDA-MB-436 cell line in vitro. The final biological evaluation confirmed that Andro was a highly effective single agent in the MDA-MB-436 xenograft model and had a low hERG-mediated cardiac toxicity. Therefore, Andro represents the first natural product, non-amide member of a novel nanomolar-potency PARP1/2 inhibitor family.

Extrusion dripping is a facile method for the preparation of millimetre-size macrobeads. In this work, a pneumatic extrusion dripping system has been established to fabricate hydroxyapatite macrobeads with a controlled size. The size of the hydroxyapatite spherical beads could be tailored by adjusting the dripping parameters. This work is believed to provide an alternative method for the fabrication of hydroxyapatite macrobeads that can be used in bone regeneration.

In this study, a novel hybrid surface plasmon waveguide structure based on CdS nanowires and metal ridges was designed. The waveguide structure was simulated and analysed at a working wavelength of 490 nm based on the finite element method. The electric field distribution, mode characteristics, transmission length and quality factor of the waveguide were studied with geometric parameters. Results show that the comprehensive performance of the waveguide can be significantly optimised by appropriately adjusting the geometric parameters of the structure. Through the optimal parameter design, the effective mode field area reaches 0.008 λ 2 , the transmission length is 21,289 nm, and the quality factor is 702.12. This waveguide structure has great potential in the fields of optoelectronic communication and optical sensing technology.

This study presents an experimental and numerical investigation on the static behavior of headed stud shear connectors in ultra-high performance concrete (UHPC) of composite bridges. Four push-out specimens were tested. It was found that no cracking, crushing or splitting was observed on the concrete slab, indicating that UHPC slab exhibited good performance and could resist the high force transferred from the headed studs. The numerical and experimental results indicated that the shear capacity is supposed to be composed of two parts stud shank shear contribution and concrete wedge block shear contribution. The stiffness increment of a stud in UHPC was at least 60% higher than that in normal strength concrete. Even if the stud height was reduced from 6d to 2d, there was no reduction in the shear strength of a stud. Short stud shear connectors with an aspect ratio as small as 2 could develop full strength in UHPC slabs. An empirical load-slip equation taking into account stud diameter was proposed to predict the load-slip response of a stud. The reliability and accuracy of the proposed load-slip equation was verified by the experimental and numerical load-slip curves.

In this paper, the electromagnetically induced transparency (EIT) effect of graphene nanostructures was studied by numerical methods. Numerous branch structures were added to the sides of the graphene/medium/graphene waveguide, and the Fabry-Perot resonators were formed between adjacent branches due to the phase coupling effect. The back and forth oscillation of electromagnetic waves in the cavity significantly enhanced the transmitted light in a narrow band. Thus, an output spectrum similar to the EIT effect was produced. The output spectrum can be further adjusted by the gate voltage with the unique electrically adjustable properties of graphene. The surface of plasmon exhibited stronger locality in graphene nanostructures than metals. Thus, graphene-based electro-optical devices were more compact and integrated in the deep sub-wavelength scale. The proposed graphene nanostructures facilitated the implementation of a variety of high performance electro-optical devices, including multi-channel selective filters, sensors, and modulators.

The bovine hydroxyapatite (BHA) was applied to prepare biological tissue engineering scaffolds by the method of extrusion freeforming. To achieve this goal, BHA were added to sodium alginate (SA) solution to form a slurry system in appropriate proportion. The resulting mixtures were fabricated to be a kind of controllable and porous scaffolds followed with cross-linking in 5% calcium chloride (CaCl2) solution for 24 h. After that, the scaffolds were sintered in air at 1 000, 1 100, 1 200 and 1 300 °C for 5 h. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies were performed on the scaffolds to analyze its microstructure and constituent. To explore the effect of sintering temperature on scaffolds, the compressive strength, volume shrinkage and water absorptivity of BHA-SA composite scaffolds after sintering were investigated. The research tests indicated the feasibility of applying BHA powder to 3D printing. Besides, the scaffolds sintered in a respectively lower temperature possess much more pores and performed higher water absorptivity, which means better cellular affinity. And scaffolds sintered between 1 100 and 1 200 °C presents higher compressive strength.

We proposed an electro-optic modulator with two-bus one-ring (TBOR) structure to improve the extinction ratio and reduce insert loss. It has a dual output compared with one-bus one-ring structure. In addition, double-layer graphene makes it possible for the modulation in the visible to mid-infrared wavelength range. It shows that this new electro-optic modulator can present two switching states well with low insertion loss, high absorption and high extinction ratio. At λ = 1550 nm , when the switching states are based on the chemical potential, μ c = 0.38 eV and μ c = 0.4 eV , the insertion losses of both output ports are less than 2 dB, the absorption of the output port coupled via a micro-ring reaches 45 dB and the extinction ratio reaches 14 dB. When the refractive index of the dielectric material is 4.2, the applied voltage will be less than 1.2 V, thus can be used in low-voltage CMOS technology.

The problem of low azimuth resolution has restricted the applicability for radar forward-looking imaging in practice. In this paper, a sparse with fast majorization-minimization (SFMM) superresolution algorithm was proposed to realize fast superresolution imaging of sparse targets in radar forward-looking area. First, we analyzed the azimuth signal of the radar forward-looking area and modeled the azimuth signal as a convolution of antenna pattern and targets distribution. Second, the superresolution problem was converted into an L1 regularization issue by introducing the L1 norm to represent the distribution of the targets under the regularization framework. Third, according to the principle of majorization-minimization (MM) algorithm, a simple L2 regularization issue was obtained to replace the difficult L1 one, and the real target distribution was obtained by solving the L2 regularization problem (We named it sparse with MM (SMM) superresolution algorithm for convenience). Then, in order to improve the computational efficiency of the algorithm, we adopted the second-order vector extrapolation idea to accelerate the conventional MM algorithm and solve the L2 regularization problem. The simulation and real data verified that the proposed SFMM algorithm not only improves the azimuth resolution in radar forward-looking imaging but also increases convergence speed on the basis of SMM superresolution algorithm.

An in-fiber integrated sensor array with the embedded weakly reflective joint surface is proposed and demonstrated. The weak reflector is formed of a single-mode fiber (SMF) and a double-cladding fiber (DCF), whose cores have different refractive index. A sensor array based on this structure is sensitive to strain and temperature, and it has the ability to achieve quasi-distributed measurements. Therefore, it can be used for structural health monitoring. Besides that, without any connector, the sensors were integrated in a fiber. Consequently, they are more suitable for a harsh test environment (space limitation or high temperature).

Electrical treatment is a useful method for reducing viscosity of waxy crude oil. Molecular dynamics simulation was employed to study the influence of electric field on viscosity of waxy crude oil and micro properties of paraffin. The waxy crude oil model consists of light oil and 24.9% by weight of paraffin. The simulation results show that viscosity decreases when electric field is applied. The larger the electric field intensity, the greater the decreasing extent of viscosity. The electrical viscosity-reducing effect is better at lower temperatures. The radial distribution function and diffusion coefficient were analyzed for explaining the reason of viscosity decreasing. The radial distribution function results confirm that electric field promotes aggregation of paraffin molecules. Diffusion coefficient increases with the increase of electric field intensity. At the same temperature, the higher the electric field strength, the larger the increasing extent of diffusion coefficient. In a certain electric field intensity, the lower the temperature, the greater the increasing extent. The changing tendency of diffusion coefficient is consistent with the trend of viscosity reduction under electrical treatment. It is suggested that the change of diffusion coefficient is the main reason for electrical viscosity-reducing effects, the contribution of aggregation is smaller than increasing of diffusion coefficient.

In human, strontium (Sr) follows the same physiological pathway as calcium and thus could be used for improving the bioactivity and osteoconductivity of hydroxyapatite (HAp) in bone tissues. Similarly, iron (Fe) can potentially play an important role in bone remodeling due to its magnetic properties. Therefore, the current study was aimed to simultaneously co-substitute Sr2+/Fe3+ in HAp nanoparticles for various potential biomedical applications. The Sr2+/Fe3+ co-substituted HAp nanoparticles were systematically synthesized through sonication-assisted aqueous precipitation method. The as-synthesized nanoparticles were evaluated for different physicochemical and biological properties. X-ray diffraction (XRD) patterns of Sr2+/Fe3+ co-substituted HAp nanoparticles confirmed their phase purity and showed hexagonal-like structure. Scanning electron microscope (SEM) micrographs showed an agglomerated rod-like morphology of HAp nanoparticles which contained pores consisted of small spheroids. The nanoparticles displayed magnetization (Ms) reliance on the loading level of mole % (X = Fe3+) and exhibited tunable porosity and microhardness (Hv) upon heat treatment. The nanoparticles showed less than 5% hemolysis demonstrating high blood compatibility with high in vitro bioactivity performance. The multifunctional properties of synthesized nanoparticles make them a potential candidate for various biomedical applications; including bone grafting and guided bone regeneration, targeted drug delivery, magnetic resonance imaging, and hyperthermia based cancer treatment.

Surface states on TiO2 photoanodes are usually considered to hinder the photoelectrochemical (PEC) water splitting via slowing charge transport and increasing charge recombination. Here, we found that electrochemically doping the TiO2 nanotubes electrode at a potential negative than its flat band potential will induce the insertion of protons into the lattice of TiO2 via a reaction of TiIVO2 + e− + H+ = TiIIIO(OH) to form the surface states. Photoelectrochemical/electrochemical tests confirmed that the surface states (Ti-OH) are an important photogenerated electron transfer route, significantly increasing charge separation efficiency, and hence contributing to the PEC performance enhancement. In addition, we have made a self-consistent explanation on Mott-Schottky (M–S) plots of the TiO2 nanotubes electrode, demonstrating that the M–S measurement is able to accurately describe electron filling and extraction into/from surface states and not suitable to determine the flat band potential of nanostructured TiO2 electrodes. Our results offer a new insight to understanding the role of surface states during the charge separation, transfer, and injection processes of the water splitting reaction.

A novel perovskite hybrid surface plasmon waveguide structure is designed. Established its physical model and introduced its theoretical basis in detail. Based on the finite element method, the mode characteristics, quality factor, and gain threshold of the waveguide structure are analyzed with geometric parameters. The results show that the optical field constraint of the waveguide can reach a good deep sub-wavelength level under the optimal operating wavelength of 1550nm. By adjusting the waveguide design parameters, the high quality factor, low energy loss, low threshold limit and ultra small effective mode field area are obtained. Compared with the hybrid waveguide structure proposed in the current research results, this structure has stronger optical field limiting ability and microcavity binding ability. The waveguide structure can provide theoretical and technical support for the development of new efficient nano laser devices, and has a good application prospect.

Transformation of organic phosphorus (P) is directly related to a range of environmental factors, therefore exploring their relationships is vital to understanding the biogeochemical cycling of P and its significance in eutrophication of lake waters. In this study, a series of experiments were conducted to simulate the organic P transformation in the water under the influence of dissolved oxygen (DO), temperature and phytoplankton growth. Results showed that the transformation rate of total organic P increased with temperature, ranging from 0.02 to 0.25 mg L−1 day−1 at 5 °C, and from 0.04 to 0.72 mg L−1 day−1at 30 °C. The transformation rate of total organic P was significantly higher under anaerobic conditions than that under aerobic conditions at 20 °C and 30 °C, indicating that DO is a more important factor for the transformation of total organic P at the high temperature. However, different compounds of organic P responded differently to environmental factors. The change of orthophosphate monoester (Mono-P) content was consistent with that of total organic P when the temperature and DO were the same, but the transformation rates of phosphonate and DNA in the water were less affected by changes of temperature and DO. Additionally, the transformation rate of Mono-P was increased by the growth of phytoplankton when it was used as a P source. Although the relationships between alkaline phosphatase (ALP) activity and organic P are complex, ALP may be the main factor affecting the transformation of organic P at lower temperatures.

Absolute localization of a flying UAV on its own in a global-navigation-satellite-system (GNSS)-denied environment is always a challenge. In this paper, we present a landmark-based approach where a UAV is automatically locked into the landmark scene shown in a georeferenced image via a feedback control loop, which is driven by the output of an aerial image registration. To pursue a real-time application, we design and implement a speeded-up-robust-features (SURF)-based image registration algorithm that focuses efficiency and robustness under a 2D geometric transformation. A linear UAV controller with signals of four degrees of freedom is derived from the estimated transformation matrix. The approach is validated in a virtual simulation environment, with experimental results demonstrating the effectiveness and robustness of the proposed UAV self-localization system.

Graft reconstruction of the mandible is an important approach that aims at improving the appearance and functionality of defected mandibles. The traditional implant materials are generally bioinert, non-degradable, and that they lack favorable pore structures for cell proliferation, which limit their clinical application. In this study, we used boron-containing bioactive glass which was combined with a three-dimensional (3D) printing technology to construct an osteoinductive implant scaffold, according to the imaging instructions of CT scan on bone defects. Here, the boron-containing bioglass scaffold (B-BGs) was prepared through sol-gel processing and a 3D print technique. Different boron content of borosilicate bioglass was prepared by incorporating B2O3 (molar: 19.4 and 38.8%) into 58S bioglass to replace parts of SiO2. For fabricated mandible implants through three-dimensional 3D printing of B-BGs (size: 8 × 2 mm; pore size: 250 μm) modified with borosilicate bioglass powder and sodium alginate. Notably, the compressive strength of the B-BGs was about 3.8 Mpa, which supported mandibular activity. Subsequently, the excellent biocompatibility of B-BGs was confirmed using cytotoxicity in vitro studies. Finally, data from in vivo experiments demonstrated that the B-BGs could promote bone regeneration and they could almost get completely degraded within 4 weeks. Our results showed that the boron-containing bioglass could repair mandibular defects.

A tunable Fano resonance based on a microring resonator is proposed. The double microring is nested in parallel in the U-shaped feedback waveguide with the graphene embedded in part of the waveguide as the active modulation region of Fano resonance. When different voltages are applied to the graphene in the feedback waveguide or microrings, the Fano resonance exhibits different and asymmetrical shapes and has a larger extinction ratio than the traditional Lorentz shape. The maximum extinction ratio of the proposed device is up to 71.50 dB. The proposed structure will have a wide application in sensors, switches, and integrated optoelectronic devices.

The inhalation of dust containing certain nickel compounds has been associated with an increased risk of lung and nasal cancers in occupational studies of workers who process or refine sulfidic nickel ores and are exposed to relatively high levels of mixtures of water-soluble, sulfidic, oxidic, and/or metallic forms of nickel. We conducted a systematic review of the potential carcinogenicity of metallic nickel, focusing on cancers of the respiratory tract. We evaluated the quality and risk of bias (RoB) of the relevant epidemiology, experimental animal, and in vitro mechanistic studies using the National Toxicology Program's Office of Health Assessment and Translation (OHAT) RoB Rating Tool. We then used a systematic review protocol based on the OHAT approach to critically assess whether metallic nickel should be considered a human respiratory carcinogen. Our evaluation of the epidemiology studies indicates that there is no substantive evidence of increased respiratory cancer risk in workers exposed predominantly to metallic nickel. Animal evidence indicates that metallic nickel does not increase the incidence of respiratory tumors in rodents exposed by inhalation. The in vitro studies are limited in value, as they bypass normal clearance mechanisms. Nevertheless, the mechanistic evidence indicates that metallic nickel is not mutagenic but can induce DNA strand breaks under certain conditions. Based on a standard framework for assessing causality, we conclude that the evidence does not support a causal relationship between metallic nickel exposure and respiratory cancer in humans.

We present TrojDRL, a tool for exploring and evaluating backdoor attacks on deep reinforcement learning agents. TrojDRL exploits the sequential nature of deep reinforcement learning (DRL) and considers different gradations of threat models. We show that untargeted attacks on state-of-the-art actor-critic algorithms can circumvent existing defenses built on the assumption of backdoors being targeted. We evaluated TrojDRL on a broad set of DRL benchmarks and showed that the attacks require only poisoning as little as 0.025% of the training data. Compared with existing works of backdoor attacks on classification models, TrojDRL provides a first step towards understanding the vulnerability of DRL agents.

Recent successes of wireless networked systems in advancing industrial automation and in spawning the Internet of Things paradigm motivate the adoption of wireless networked systems in current and future safety-critical applications. As reliability is key in safety-critical applications, in this work we present NetDAG, a scheduler design and implementation suitable for real-time applications in the wireless setting. NetDAG is built upon the Low-Power Wireless Bus, a high-performant communication abstraction for wireless networked systems, and enables system designers to directly schedule applications under specified task-level real-time constraints. Access to real-time primitives in the scheduler permits efficient design exploration of tradeoffs between power consumption and latency. Furthermore, NetDAG provides support for weakly hard real-time applications with deterministic guarantees, in addition to heretofore considered soft real-time applications with probabilistic guarantees. We propose novel abstraction techniques for reasoning about conjunctions of weakly hard constraints and show how such abstractions can be used to handle the significant scheduling difficulties brought on by networked components with weakly hard behaviors.

In this paper, a grating-coupled surface plasmon resonance concentration sensor employing a gold and indium tin oxide (Au/ITO) nanoparticle composite instead of metal is proposed. The structure and material parameters of the sensor are discussed and analyzed. Taking the ethylene glycol concentration as an example, the influence of the nanocomposite on the wave vector matching, the influence of the refractive index of the medium to be tested and the influence of the concentration on the refractive index were analyzed in detail. The experimental results show that when the sensor is used for the measurement of ethylene glycol concentration, the correlation coefficient between the concentration and the refractive index is as high as 0.999995. The fitting curve and data correlation are good, and the sensitivity has a good linear relationship with the sensitivity. Therefore, the sensor structure proposed in this paper can be used to accurately measure the trace concentration of liquid, and its sensing mode has certain reference value for the measurement of general trace fluid concentration.

Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging and nonpersistent contaminants. In this study, 27 PPCPs in various water samples were extracted by solid phase extraction (SPE), and determined by isotope dilution method using liquid chromatography coupled to tandem triple quadruple mass spectrometer (LC-MS/MS). A total of 27 isotopically labeled standards (ILSs) were applied to correct the concentration of PPCPs in spiked ultrapure water, drinking water, river, effluent and influent sewage. The corrected recoveries were 73%–122% with the relative standard deviation (RSD) < 16%, except for acetaminophen. The matrix effect for all kinds of water samples was < 22% and the method quantitation limits (MQLs) were 0.45–8.6 ng/L. The developed method was successfully applied on environmental water samples. The SPE extracts of spiked ultrapure water, drinking water, river and wastewater effluent were stored for 70 days, and the ILSs-corrected recoveries of 27 PPCPs were obtained to evaluate the correction ability of ILSs in the presence of variety interferences. The recoveries of 27 PPCPs over 70 days were within the scope of 72%–140% with the recovery variation < 37% in all cases. The isotope dilution method seems to be of benefit when the extract has to be stored for long time before the instrument analysis.

Neural networks are widely used in many applications ranging from classification to control. While these networks are composed of simple arithmetic operations, they are challenging to formally verify for properties such as reachability due to the presence of nonlinear activation functions. In this paper, we make the observation that Lipschitz continuity of a neural network not only can play a major role in the construction of reachable sets for neural-network controlled systems but also can be systematically controlled during training of the neural network. We build on this observation to develop a novel verification-aware knowledge distillation framework that transfers the knowledge of a trained network to a new and easier-to-verify network. Experimental results show that our method can substantially improve reachability analysis of neural-network controlled systems for several state-of-the-art tools.

Although demanding, the development of multifunctional theranostic nanoplatforms is attracting considerable worldwide interest. Herein, a theranostic nanoplatform with multifunctions based on polydopamine (PDA) nanoparticles (NPs) was developed, owning dual-imaging and dual-therapy functions for cancer theranostic applications. PDA NPs were generated using a facile polymerization method under alkaline conditions, followed by poly(ethylene glycol) (PEG) modification. Then, the obtained NPs were loaded with IR820 and Fe3+ ions to produce the final PEGylated PDA/IR820/Fe3+ (PPIF) NPs. The PPIF NPs thus generated displayed increasingly brighter photoacoustic and magnetic resonance signals with increasing NP concentration and were demonstrated to be cytocompatible and effectively taken up and internalized into HeLa cells. Under near-infrared light irradiation, PPIF NPs can produce heat and reactive oxygen species for photothermal/photodynamic combined cancer therapy. In this study, the versatility of PDA NPs was demonstrated to be promising as a multifunctional nanoplatform for potential cancer theranostic applications.

Earlier reports of fabricating 3D porous PCL scaffolds for tissue engineering applications were overshadowed by several limitations such as additional molds cost, relatively low efficiency, and lacking process control. In present study, combined extrusion-based cryogenic 3D printing (ECP) (−20 °C) and subsequent freeze-drying approaches were employed to facilely fabricate polycaprolactone (PCL) scaffolds, with high porosity and fidelity. Freeze-drying caused shrinkage of the scaffolds along X, Y, and Z-axes to some extent. The porosities of CP600, CP800, and CP1000 were found to be 64.0 ± 1.2%, 70.1 ± 1.3%, and 74.3 ± 0.6%, respectively. The fabricated scaffolds were characterized for various structural features and compared with the ones fabricated through traditional extrusion-based melt 3D printing (EMP). The crystallinity of PCL in ECP scaffolds was lower (57.1 ± 2.2%) than EMP scaffolds (69.8 ± 1.3%). The ECP scaffolds showed high alkaline degradation, but low compression properties. The ECP scaffolds promoted the adhesion and proliferation of MCT3T-E1 cells with well-spread morphology on the porous filaments. Together, these features justify the suitability of printed PCL scaffolds for potential TE applications. Keywords: Extrusion-based cryogenic 3D printing, Polycaprolactone, Glacial acetic acid, 3D scaffold, Tissue engineering

Sluggish water dissociation kinetics on nonprecious metal electrocatalysts limits the development of economical hydrogen production from water–alkali electrolyzers. Here, using Co3N electrocatalyst as a prototype, we find that during water splitting in alkaline electrolyte a cobalt-containing hydroxide formed on the surface of Co3N, which greatly decreased the activation energy of water dissociation (Volmer step, a main rate-determining step for water splitting in alkaline electrolytes). Combining the cobalt ion poisoning test and theoretical calculations, the efficient hydrogen production on Co3N electrocatalysts would benefit from favorable water dissociation on in-situ formed cobalt-containing hydroxide and low hydrogen production barrier on the nitrogen sites of Co3N. As a result, the Co3N catalyst exhibits a low water-splitting activation energy (26.57 kJ mol–1) that approaches the value of platinum electrodes (11.69 kJ mol–1). Our findings offer new insight into understanding the catalytic mechanism...

The Polycaprolactone (PCL) fibrous scaffolds in nano to micro scale have been considered as excellent templates for cell culture and tissue growth. The hydrophobic nature of the PCL, however, yields low initial cell seeding density, heterogeneous cell spreading and slow cell growth rate. Therefore, in this study the surface hydrophilic fibrous scaffolds were directly fabricated by the electrospinning of PCL solutions with small quantities (0.5–5%) of Pluronic F127 (PEO100-PPO65-PEO100) dissolved in benign solvent of glacial acetic acid. The clear and miscible solutions were achieved by controlling the proper F127 content in the blend solutions. The continuous and smooth fibers with average diameters from 0.71 to 1.43 μm made up the fibrous scaffolds in non-woven mode. Then the water wetting angle of the scaffolds could be adjusted from 126° to 0° by varying F127 content owing to its hydrophilic PEO chains presented on surface the blended fibers. Finally, it was demonstrated that the blended fibrous scaffolds with the F127 content less than 1% exhibited better cell attachment, proliferation and spreading performance than those of pure PCL scaffolds.

The source, quantity and quality of sedimentary organic matter (SOM) were investigated in the surface sediments of Lake Fuxian, a deep oligotrophic lacustrine system in China. Granulometry, biochemical organic composition, bulk organic proxies and their stable isotopes were determined in the surface sediments (0–4 cm). The values of δ13C, δ15N and atomic ratio of total organic carbon to total nitrogen (TOC/TN) indicated that the sediments in the large partial lake were influenced by autochthonous organic matter. The concentrations of TOC, protein (PRT) and total hydrolysable amino acids may be mainly modulated by phytodetritus sinking from euphotic zones since they correlated significantly with chlorins. Otherwise, the lack of correlation between chlorins concentrations and carbohydrate (CHO) and lipid (LIP) indicated that the latter may have an additional terrestrial source. The highest sediment quantity was found in the deepest station NC owing to its fine sediment. Stations near northwestern shore accumulated more SOM than other littoral stations, which was in accordance with sewage discharge strength. Degradation quality indices, such as chlorin index, degradation index, PRT/CHO, and LIP/CHO, were in general agreement in showing the degraded status of SOM in Lake Fuxian. No clear spatial patterns were found in sediment degradation quality, which may be influenced by bottom oxygen concentration in the deep stations.

For photoelectrochemical (PEC) water splitting, the interface interactions among semiconductors, electrocatalysts, and electrolytes affect the charge separation and catalysis in turn. Here, through the changing of the bath temperature, Co-based oxygen evolution catalysts (OEC) with different crystallinities were electrochemically deposited on Ti-doped Fe2O3 (Ti–Fe2O3) photoanodes. We found: (1) the OEC with low crystallinity is highly ion-permeable, decreasing the interactions between OEC and photoanode due to the intimate interaction between semiconductor and electrolyte; (2) the OEC with high crystallinity is nearly ion-impermeable, is beneficial to form a constant buried junction with semiconductor, and exhibits the low OEC catalytic activity; and (3) the OEC with moderate crystallinity is partially electrolyte-screened, thus contributing to the formation of ideal band bending underneath surface of semiconductor for charge separation and the highly electrocatalytic activity of OEC for lowering over-pot...

Magnetic treatment is a widely used physical treatment technique in oilfields. The influencing mechanism of magnetic field on waxy crude oil has drew much attention in recent years. Molecular dynamics simulation was employed in this paper to study the influence of magnetic field on waxy crude oil. The waxy crude oil model consists of light oil and 24.9% by weight of paraffin. The simulation results showed that the density of waxy crude oil model firstly decreased and then increased with the strengthening of magnetic field intensity, while the diffusion coefficient increased in low magnetic field intensity and decreased in high intensity. Viscosity was calculated by Rouse Model. The reduction of viscosity only appeared within a specific range of magnetic field intensities, mainly concentrated on the low intensities. The viscosity increases when the range is overstepped, which is supposed to be the reason of the unstable effects of magnetic treatment. The aggregation of paraffin molecules in magnetic field was proved by analysing the radial distribution function. The analysis of energy represented that the magnetic field had greater influence on molecular morphology than distances between molecules. The simulation results provide micro-perspective of waxy crude oil in the presence of magnetic field, which help to offer the mechanism explanation of magnetic treatment effects.

Two actinomycete strains, NEAU-C11T and NEAU-C8, isolated from rhizosphere soil and wheat root, respectively, collected from Langfang, Hebei Province, China. A polyphasic study was carried out to establish the taxonomic position of the two strains. Morphological and chemotaxonomic characteristics of the isolates coincided with the genus Glycomyces. Sequences analysis of the 16S rRNA gene also showed that the organisms belong to the genus Glycomyces and Glycomyces algeriensis is the highest sequence match for both strains. Furthermore, a combination of DNA-DNA hybridization results and some differential physiological and biochemical properties indicated that they were distinguishable from the phylogenetically closest relatives. Therefore, the two strains represent a novel species, for which the name Glycomycesrhizosphaerae sp. nov. is proposed. The type strain is NEAU-C11T (=CGMCC 4.7396T=DSM 104646T).

Graphene-based electrocatalytic materials are potential low-cost electrocatalysts for the oxygen evolution reaction (OER). However, substantial overpotentials above thermodynamic requirements limit their efficiency and stability in OER-related energy conversion and storage technologies. Here, we embedded CrN crystals into graphene and in situ electrochemically oxidized them to construct graphene materials with encapsulated Cr6+ ions (Cr6+@G). These Cr6+@G materials exhibit the lowest OER overpotential of 197 mV at 10 mA cm−2 and excellent stability over 200 h at a high current density of about 120 mA cm−2 in an alkaline electrolyte. Spectroscopic and computational studies confirm a stable ion coordination environment significantly benefiting the downshift of the graphene Fermi level via hybridization of C p orbitals with d orbitals of Cr6+ ions that enhances the OER activity and stability.

Echo State Network (ESN) is often used for time series prediction and chaotic series prediction.But in the training process of ESN model, the reserve pool will involve a large number of calculations, so the reserve pool may have node redundancy, resulting in inaccurate training model. It is very important to select the active nodes in the reserve pool because the predicted nodes are very few compared with all the nodes in the reserve pool. Based on the characteristics of the original vector, compressed sensing can reduce the dimension of the vector so as to obtain the activated nodes. In this paper, the ESN model is added with compressed sensing, which simplifies the reserve pool part of the ESN model. The simulation results show that our method can not only reduce the calculation amount of training effectively, but also improve the accuracy.

The plasmon resonance effect of metal nanoparticles (NPs) offers a promising route to improve the solar energy conversion efficiency of semiconductors. In this study, it is revealed that hot electrons generated by the plasmon resonance effect of Au NPs tend to inject into the surface states instead of the conduction band of Fe2 O3 photoanodes, and then severe surface recombination occurs. Such an electron-transfer process seems to be independent of external applied potentials, but is sensitive to metal-semiconductor interface properties. Passivating the surface states of Fe2 O3 with a noncatalytic Al2 O3 layer can construct an effective resonant energy-transfer interface between Ti-doped Fe2 O3 (Ti-Fe2 O3 ) and Au NPs. In such a Ti-Fe2 O3 /Al2 O3 /Au electrode configuration, the enhanced photoelectrochemical (PEC) water-splitting performance can be attributed to the following two factors: 1) in the non-light-responsive wavelength range of Au NPs, both the relaxing Fermi pinning effect of the Al2 O3 passivation layer and the higher work function of Au enlarge band bending; thus promoting the charge separation; and 2) in the light-responsive wavelength range of Au NPs, the effective resonant energy transfer contributes to light harvesting and conversion. The interface manipulation proposed herein may provide a new route to design efficient plasmonic PEC devices for energy conversion.

Chlorine bleaching technology (C process, CEH process, H process and theirs combination), which was identified as a primary formation source of PCDD/Fs, is still widely used by the vast majority of Chinese non-wood pulp and paper mills (non-wood PMs). The purpose of this study was to provide information and data support for further eliminating dioxin for non-wood PMs in China, and especially to evaluate the PCDD/Fs release reduction for those mills converting their pulp bleaching processes from CEH to ECF. The PCDD/Fs concentrations of the bleached pulp and bleaching wastewater with ECF bleaching were in the ranges of 0.13–0.8 ng TEQ kg −1 , and 0.15–1.9 pg TEQ L −1 , respectively, which were far lower than those with CEH process, indicating that the ECF process is an effective alternative bleaching technology to replace CEH in Chinese non-wood PMs to reduce dioxin release. The release factor via flue gas of the alkali recovery boiler in Chinese non-wood PMs was first reported to be 0.092 μg TEQ Ad t −1 in this study. On the assumption that pulp bleaching processes of all Chinese non-wood PMs were converted from CEH to ECF, the annual release of PCDD/Fs via the bleaching wastewater and bleached pulp would be reduced by 79.1%, with a total of 1.60 g TEQ.

Pyrolysis of supramolecular assembly precursor is a promising method to prepare graphite carbon nitride (g-C3N4), and the topological structure of the precursor assemblies largely determine the morphology and photoelectric properties of g-C3N4. In this paper, uniformly and highly porous g-C3N4 nanotubes were synthesized under the assistance of 1,5-naphthalene disulfonic acid (NA) through the melamine (MA)-cyanuric acid (CA) precursor self-assembly strategy. The as-synthesized g-C3N4 nanotubes in the presence of 75 mg/L NA (MNCA-75) exhibited the highest BET surface area (SBET) of 100.40 m2/g, and the smallest band gap (Eg) of 2.31 eV. 10 mg/L of sulfamethoxazole (SMX) was completely degraded within 120 min with the MNCA-75, and the degradation reaction conformed to pseudo-first-order kinetics. This paper reported a facile but effective method to prepare highly porous g-C3N4 nanotubes with large surface area and excellent photocatalytic performance.

Developing highly efficient, reusable, non-toxic and low-cost catalysts is of great importance for persulfate-based advanced oxidation processes (AOPs). In this work, ferrocene was mixed into paraffin to prepare a candle, and the iron-containing candle soots were collected and heated at 500 °C~900 °C under N2 atmosphere for 1 h to prepare magnetically recyclable Fe0/Fe3O4@porous carbon (Fe0/Fe3O4@PC) catalysts. The Fe0/Fe3O4@PC-700 obtained after pyrolysis at 700 °C exhibited the best catalytic activity for sulfamethoxazole (SMX) degradation. 10 mg/L SMX could be completely degraded within 10 min by 0.2 g/L of Fe0/Fe3O4@PC-700 and 0.5 mM PMS at pH 5.0. The carbon shell effectively inhibited the Fe leaching of Fe0/Fe3O4@PC-700, and 99.73% of Fe was retained after five consecutive cycles. In the Fe0/Fe3O4@PC-700/PMS system, SMX was degraded through the sulfate radical (SO4·¯), hydroxyl radical (·OH), superoxide radical (O2·¯) dominated radical pathway, and the singlet oxygen (1O2) dominated non-radical pathway. The coexisting inorganic ions and natural organic matters (NOM) in actual water inhibited the degradation of SMX. Finally, four possible degradation pathways were proposed based on the degradation intermediates of SMX. This work provides a facile heat treatment of iron-containing candle soots strategy to prepare the metal@carbon catalysts for PMS-based AOP.

The paper presents a passive auto-focusing technology by combining the discrete cosine transform(DCT) algorithm and small univalve segment assimilating nucleus(SUSAN) algorithm with evaluation function. The new method has the advantage of unimodal, local extremum and sensitivity of the focus curve. For the focusing search algorithm, the improved mountain climbing method which combined the large step and small step has been proposed, it makes the micro-vision system could find the focal plane more quickly and accurately.

This paper presents a method for extraction of real modal parameters for identification of time-varying systems using adaptable functional series vector time-dependent autoregressive (AFS-VTAR) model. In the practical application of AFS-VTAR model, both real modal parameters and computational ones may mix together in the identified results. In order to extract the real ones from computational ones, a new method based on the eigen-decomposition of the state matrix constructed in AFS-VTAR is proposed. The efficiency of the proposed method is successfully demonstrated first through numerical simulations applied to a time-varying 3-degree-of-freedom system and then experimentally by applying it to a flexible robot in motion.

Lake Gehu is a severely eutrophic lake in southeast China. A series of restoration measures have been implemented since 2009 in northern Lake Gehu. This study compared aquatic plants, water quality, sediment, and phytoplankton between restoration and control areas to investigate the effect of restoration measures. The results demonstrated that aquatic macrophyte coverage increased from 0% to 10.6%; mean TP, TN, and CODMn concentrations increased by 50.0%, 42.4%, and 40.8%, respectively, compared with those before the measures were carried out; the mean Secchi depth (SD) increased to 42.5 cm, which is 1.4 times higher than that before restoration; the mean euphotic depth (Zeu) in the summer increased from 91 to 130 cm; the mean chl a concentration decreased from 34.8 to 20.2 μg/L, compared with that before restoration; the Shannon-Wiener index of phytoplankton increased by 28.7%. The mean TP and TN concentrations in sediments decreased by 63.8% and 52.4%, respectively, compared with that before dredging. These results indicate that the restoration in northern Lake Gehu was effective. To complete the transformation from an algae- to a macrophyte-stable state within the region, further measures must be adopted. This restoration of a eutrophic lake can serve as a reference for similar eutrophic lakes.

Organofluorinated surfactants are widely employed in textile finishing agents (TFAs) to achieve oil, water, and stain repellency. This has been regarded as an important emission source of per-and polyfluoroalkyl substances (PFASs) to the environment. China is the biggest manufacturer of clothes, and thus TFA production is also a relevant industrial activity. Nevertheless, to date, no survey has been conducted on PFAS contents in commercially available TFAs. In the present study, TFA products were investigated by the Kendrick mass defect method. The quantification results demonstrated a significant presence of perfluorooctane sulfonate (0.37 mg/L) in TFAs manufactured by electrochemical fluorination technology. The products obtained by short-chain PFAS-based telomerization were dominated by perfluorooctanoic acid (mean concentration: 0.29 mg/L), whose values exceeded the limits stated in the European Chemical Agency guidelines (0.025 mg/L). Moreover, the total oxidizable precursor assay indicated high levels of indirectly quantified precursors with long alkyl chains (C7-C9). Together, these results suggest that there is currently a certain of environmental and health risks in China that originates from the utilization of TFAs, and a better manufacturing processes are required to reduce such risks.

Target detection is an important function of forward-looking scanning radar search and tracking applications. However, it is difficult to detect the targets using the real beam image with low azimuth resolution. In this paper, a target detection scheme is proposed for forward-looking scanning radar. First, an image with better resolution is obtained by deconvolution technique, and it is used to map a patch-image. Then, according to the low rank characteristic of the patch-image and the sparse characteristic of the targets, the target detection is converted into an optimization problem of low rank and sparse matrix decomposition. Finally, the targets are obtained by solving this optimization problem. Simulations are given to verify its effectiveness.