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IntroductionWith the population aging, osteoporosis has become a major public health concern. Elevated oxidative stress is a vital detrimental factor for bone health. Compared to common oxidative stress-related biomarkers, Fluorescent Oxidation Products (FlOPs) reflect the global levels of oxidation from proteins, lipids, and DNA. Nevertheless, whether plasma FlOP levels are related to bone health measured by Quantitative ultrasound (QUS) is unclear. Thus, the present study examined the association between FlOPs and QUS parameters in middle-aged and elderly adults.MethodsThis community-based cross-sectional study was conducted in Changchun, northeast China. Plasma FlOPs were determined by a fluorescent microplate reader at a wavelength of 320/420 nm (excitation/emission). QUS parameters [speed of sound (SOS) and broadband ultrasound attenuation (BUA)] of the calcaneus were assessed by an ultrasound bone densitometer. We used multivariable linear regression to examine the association between FlOPs and QUS parameters.ResultsA total of 491 subjects were included in this study. Their average age was 65.2 years (standard deviation [SD]: 9.7 years). FlOPs were inversely associated with SOS (β for an increase of logarithmic interquartile range = −10.64; P = 0.018). Higher FlOP levels were marginally associated with lower SOS in females (β for an increase of logarithmic interquartile range = −9.68, P = 0.066), but not in males (β for an increase of logarithmic interquartile range = −11.84, P = 0.131). No significant relationship between FlOPs and BUA was observed.ConclusionsPlasma FlOP levels were inversely associated with SOS, but not with BUA in middle-aged and elderly adults.

Despite the great advantages of interconnected porous architectures of three-dimensional carbon as functional materials, apparent common drawbacks restricting their widespread applications are high cost and non-renewable of the carbon precursors and complicated activation procedures. In this study, biomass-derived honeycomb-like multilayered carbon (HMC) is synthesized by electrospraying and direct carbonization for the first time. Poly (methyl methacrylate) (PMMA) is mixed with biomass-derived lignin, the only carbon source, to form lignin/PMMA microspheres and microbowls by electrospraying. One-step carbonization of prepared micromaterials to obtain ultralight HMC, and the microstructures and pore size of carbon materials are controllable by adjusting the applied voltage of electrospraying. The obtained HMC-13 by carbonization of lignin/PMMA microspheres possesses interconnected carbon skeleton, partially graphitized structure and hierarchical pore system composed of macropores, mesopores and micropores. Benefiting from the structural advantages, HMC-13 as electrode of supercapacitor delivers a high specific capacitance of 348 F g−1 at 0.5 A g−1 in aqueous electrolytes. Additionally, the supercapacitor exhibits excellent cycling stability with only 4% capacitance loss after 10 000 cycles. Based on these encouraging results, environmental friendliness and facile synthesis strategy, the biomass-derived ultralight porous carbon material holds great promise for facilitating wasted biomass utilization and developing sustainable energy products.

* Revised： [19-13 , 2019], The spatial unbundling of parts production and assembly currently characterizes globalization, leading to the worldwide dispersion of pollution. We consider socially optimal (cooperative) environmental taxes in a two-country model of global value chains in which the location of both parts and assembly can differ. When unbundling costs are so high that parts and assembly must colocate in the pre-globalized world, pollution is spatially concentrated, and harmonizing environmental taxes maximizes global welfare. In contrast, with low unbundling costs triggering the dispersion of parts and thus pollution throughout the world as today, harmonization fails to maximize global welfare. Similar results hold when the two countries non-cooperatively choose their environmental taxes.

With the introduction of cold electron sources such as nanotubes, X-ray sources became small in size so that many sources are installed in array to form stationary CT, which brings benefits of simplicity in mechanism and fast response. However, the nanotube-based X-ray source is still singly packaged and hence density of X-ray sources is limited, which introduces severe sparse-view artifacts and could not be used in practice. With the invention of X-ray sources device based on ZnO nanowires as cold electron emitters, a large amount of X-ray sources is first integrated in a flat panel device. In this study, we design a stationary CT architecture using high-density sources devices, called HD-SCT, and develop corresponding reconstruction algorithm. Specifically, several flat panel detectors and X-ray sources devices are spliced together to form a source-detector plate. Multiple source-detector plates are organized as a polygon that encloses object to complete CT scanning. In HD-SCT, X-ray sources are close to object which can significantly decrease CT device volume. The X-ray beam emitted by each source just cover part of object and the spot sources alternately light to completely scan object. Simultaneously, we propose a reconstruction method for the specific configuration which adopts an iterative algorithm to resolve the reconstruction based on alterative part projections, as well as a novel correction process of projection completion for the shadowed area of placing X-ray source devices. To validate the design of the proposed HD-SCT, we execute a series of simulation experiments, which show that the proposed HD-SCT and corresponding reconstruction method effectively remove the artifacts caused by the embed X-ray source device. The results also disclose that with the increase of density of X-ray sources, the resolution of reconstruction has been dramatically improved, which demonstrates the practical value of introducing high-density X-ray sources device into stationary CT design.

This version: April 2021, First version: October 2018, Consumption is an important source of greenhouse gas (GHG) emissions. This study theoretically analyzes how trade liberalization and consumption tax affect firm locations across countries and GHG emissions originating from consumption. Introducing consumption-originated emissions in a standard footloose capital model, we find several novel results that extend previous analyses of production-originated GHG emissions. First, trade liberalization has a non-monotonic effect on global emissions; that is, as trade costs decline, global emissions initially decrease and then increase. Second, consumption taxes cause carbon leakage; that is, the tax on one country reduces emissions in that country, while increasing it in the rest of the world. Third, optimal consumption taxes that maximize global welfare must be neutral about firm location decisions. In particular, even if firms are asymmetrically distributed across countries in the absence of a consumption tax, the optimal tax level must be identical across countries.

An empirical 3-D model was developed to evaluate the effect of ambient environment on the mechanical properties and degradation behavior of bamboo-bundle laminated veneer lumber (BLVL) fabricated with different levels of PF/PVAc resin. This model can describe the relationship between the modulus of elasticity (MOE), water absorption ratio, and aging temperature. Five levels of PF/PVAc weight ratio (2:1, 4:1, 6:1, 8:1 and 10:1) and three treatment conditions (18, 63, and 100 °C) were examined in this experiment. Computed tomography (CT) scanning technology was employed to observe the morphology of damage degree as well as explore the mechanism of degradation behavior of BLVL. The results indicated that the 3-D model used for tracking and monitoring the variance of MOE provided good predictors. The higher the water impregnation temperature the larger the water absorption ratio and the higher the MOE degradation were. The aging temperature had a significant effect on the mechanical properties and degradation behavior of BLVL. A linear relationship between modulus of rupture (MOR) degradation and aging temperature was observed. The degradation rate of MOE and MOR increased as the temperature increased. The aging degree tested by CT along with damage of inner board showed the PF/PVAc ratio had a significant influence on the mechanical degradation of treated BLVL when the PF/PVAc ratio was below 6:1. Localized yielding, micro-cracks developing between interfaces, PVAc resin softening along with delamination, and debonding were the main failure models for the BLVL by hygrothermal aging treatment.

Compton scatter tomography can reconstruct the electron density distribution using the first-order Compton scattered photons, and has the potential of identifying different materials. However, in Compton scatter tomography, the detected photons may come from all voxels illuminated by the x-ray beam and the information is blended. Although the mixing could be reduced using mechanical collimation, the detected photon number will decrease seriously, which tampers the reconstructed image quality greatly. This paper proposes a Compton scatter tomography scheme based on the scatter physics and photon-counting detector. The Compton scatter photons could be detected without mechanical collimation while fan-beam CT scanning, and scattered signal can be separated into signals emitted from subsets of the entire volume due to geometry constraints associated with energy selection of the photon-counting detector. An analytical model of first-order Compton scatter projection procedure is constructed, and a compressed sensing based method is utilized to reconstruct the electron density distribution. Experiment results demonstrate the accuracy of the signal acquisition model, and the proposed imaging scheme can represent the anatomical structure of the object in electron density.

Understanding the effect of moisture absorption on the mechanical properties of fibers at cellular level is key important to the application of natural fibers in reinforcement composites. This study focused on the variation of the modulus of elasticity (MOE) of several representative individual cellulosic fibers (bamboo, Chinese fir, ramie and Kevlar) under different relative humidity condition (RH: 40 %, 70 %, 90 %), dedicating for the screening of appropriate candidates of fibers used in outdoors. A special custom-designed microtester (SF-I) with the micro humidity control box was devised in order to observe stress-strain behavior of fibers under different humidity condition. Among the fibers investigated, ramie fiber presented the most sensitive to the humidity, Chinese fir and bamboo fiber was followed, and Kevlar fiber showed the bluntest to moisture variation since it belonged to artificial fiber. Compared with the fibers tested at RH of 40 %, the MOE of Bamboo, Chinese fir, Ramie fibers increased at RH 70 %, and decreased at RH 90 %, respectively. The optimal tensile properties were observed for the bamboo fiber among tested single plant fibers, with a MOE value of 26.3-30.7 GPa, and RH of 70-80 % was deduced for obtaining the highest value of MOE under various humidity testing condition.

The occurrence of an interactive effect between warp and weft of woven fabrics under practical working conditions is an important concern for researchers. A novel 3D loading device has therefore been developed to elucidate information on materials subjected to loadings in multiple dimensions. This paper investigated the interactive effects between warp and weft in biaxial tension. Strain fields were characterized by digital speckle correlation method and Poisson’s ratio was calculated at 0° in the warp direction. The effects of different cutting angles and loading threshold values at 0° on the interactive effect were also evaluated. An interactive effect between warp and weft existed, and the influence of load at weft to warp was larger than warp to weft. Weft produced larger strain fields in both directions. As the load in the warp direction linearly increased, force values nonlinearly increased while load ratio decreased. Poisson’s ratio, however, was practically unchanged. Loading mean value curves at ...

Mechanical properties of woven ramie fabric under 3D loadings are fundamental to optimizing the design of woven composites that are frequently subjected to complex stress states. This work proposes a novel 3D test analysis system for evaluating woven natural-fiber fabrics under multidimensional loads. The effects of different loading directions, uniaxial (X direction), biaxial (X and Y), bursting (Z direction), and 3D loading (X, Y, and Z) on the breaking strength of the woven ramie (Boehmeria nivea) fabric were compared. Weft breaking strength was lower than that of warp under uniaxial tension. Variability in warp and weft increased in biaxial tension. Bursting strength was significantly affected by the type of loading head used, with an R20 spherical head producing the highest strength values. Warp and weft were positively correlated under biaxial tension, r = 0.58. The synergistic effect of bursting strength accounted for 12.5% of the total correlation under 3D loadings.

As a new textile fiber produced from Neosinocalamus affinis, the structures of the bamboo fiber were studied thoroughly in this research. Using Fourier-transform infrared (FTIR) (using a Micro-FTIR Spectrometer), X-ray diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM), we investigate the chemical composition, crystalline structure, molecular and morphology structure, respectively. Results show that the chemical composition of bamboo fiber is the same as all bast fibers, that is, cellulose constitutes the majority and lignin needs to be reduced further for textile applications. The bamboo fiber belongs to cellulose I crystalline structure as flax, cotton and ramie, while has a small molecular mass and a low degree of polymerization. The cross section of the single bamboo fiber is round with small lumen. It can be predicted that bamboo fiber has high breaking strength, but low elongation and has good water absorption properties. The structural characteristics of the bamboo fiber are different from those of other textile plant fibers.