Selection of antigenically advanced variants of seasonal influenza viruses

Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent se

Application of rod-shaped cellulose nanocrystals in polyacrylamide hydrogels

Rod-shaped cellulose nanocrystals (CNCs) were manufactured and used to reinforce polyacrylamide (PAM) hydrogels through in situ free-radical polymerization. The gelation process of the nanocomposite hydrogels was monitored on a rheometer using oscillatory shear. The chemical structure, morphology, swelling property, and compression strength of the formed gels were investigated. A possible mechanism for forming hydrogels was proposed. The results showed that CNCs accelerated the formation of hydrogels and increased the effective crosslink density of hydrogels. Thus CNCs were not only a reinforcing agent for hydrogel, but also acted as a multifunctional cross-linker for gelation. The shear storage modulus, compression strength and elastic modulus of the nanocomposite hydrogels were significantly improved because of good dispersion of CNCs in PAM as well as enhanced interfacial interaction between these two components. Among the CNC contents used, a loading of 6.7 w/w% led to the maximum mechanical properties for nanocomposite hydrogels

A new insight into the mechanism of Ce enhancing high temperature oxidation resistance of hot-formed steel

In this paper, the effect of Ce addition on high temperature oxidation behavior of hot-formed steel was studied by high temperature oxidation experiment. The structure and phase composition of surface oxide layer of specimens with different Ce content were systematically analyzed by SEM, EDS, XPS. The results showed that the addition of Ce promoted the formation of a dense oxide layer during the initial oxidation stage, and effectively weaken the oxidation degree of the steel surface. Meanwhile, the Ce2O3 particles segregation in Si–Cr rich phase reduced the concentration of vacancy defects in oxide layer and enhanced the adhesion between oxide layer and substrate. After Ce addition, the surface oxidation resistance of hot-formed steel is significantly improved

Patterns and determinants of wood physical and mechanical properties across major tree species in China

The physical and mechanical properties of wood affect the growth and development of trees, and also act as the main criteria when determining wood usage. Our understanding on patterns and controls of wood physical and mechanical properties could provide benefits for forestry management and bases for wood application and forest tree breeding. However, current studies on wood properties mainly focus on wood density and ignore other wood physical properties. In this study, we established a comprehensive database of wood physical properties across major tree species in China. Based on this database, we explored spatial patterns and driving factors of wood properties across major tree species in China. Our results showed that (i) compared with wood density, air-dried density, tangential shrinkage coefficient and resilience provide more accuracy and higher explanation power when used as the evaluation index of wood physical properties. (ii) Among life form, climatic and edaphic variables, life form is the dominant factor shaping spatial patterns of wood physical properties, climatic factors the next, and edaphic factors have the least effects, suggesting that the effects of climatic factors on spatial variations of wood properties are indirectly induced by their effects on species distribution

Mechanical properties and in vitro degradation of electrospun bio-nanocomposite mats from PLA and cellulose nanocrystals

Fibrous bio-nanocomposite mats consisting of cellulose nanocrystals (CNCs) and poly(lactic acid) (PLA) were electrospun from a solvent mixture consisting of N,N\u27-dimethylformamide and chloroform at room temperature. Morphological, mechanical and thermal properties, as well as in vitro degradation of nanocomposite mats were characterized as a function of material composition. Average diameter of the electrospun fibers decreased with increased CNC-loading level. Thermal stability, and tensile strength and modulus of nanocomposite mats were effectively improved by the addition of CNCs up to the 5 wt% level. The reinforcement of CNCs on electrospun mats was illustrated by the observation of SEM-based morphologies on the tensile fracturing process of nanocomposite mats. At the CNC content of 5 wt%, the maximum tensile stress and Young\u27s modulus of the nanocomposite mats increased by 5 and 22 folds than those of neat PLA mats, respectively. Moreover, compared with neat PLA mats, the nanocomposite mats, especially at high CNC-loading levels, degraded more rapidly in phosphate-buffered saline solution

Experimental study and numerical simulation analysis of shear behavior of coral aggregate reinforced concrete beam

In order to investigate the shear behavior of coral aggregate reinforced concrete beam (CARCB), the different concrete strength, steel types affect the shear behavior of CARCB was studied, the calculation formula of shear capacity (Vcs) and numerical analysis model of CARCB was proposed. The results show that: All kinds of CARCB have inclined section suitable reinforcement failure, the failure law of CARCB and ordinary aggregate reinforced concrete beam (OARCB) was basically the same. Considering stirrups corrosion and nonlinear mechanical properties characteristic of coral aggregate concrete (CAC), the Vcs calculation formula of CARCB was proposed, and its applicability in C25 ∼ C60 CARCB was verified, its accuracy was 26% and 34% higher than GB50010–2020 and JGJ/T 12–2019, respectively. A numerical analysis model suitable for describing the shear behavior of CARCB was proposed based on K&C (Karagozian & Case) theory, and its applicability in C25 ∼ C60 CARCB was verified, it was found that this model can well describe the whole process of CARCB inclined section failure, and the errors between simulated and measured values of Vcr, Vcs and midspan deflection are 0∼18%. In addition, the Vcs obtained by the numerical model is 3% more accurate than the calculation formula, indicating that the numerical model can effectively distinguish the variation law of shear behavior of CARCB

Characterization of Biochar Derived from Pineapple Peel Waste and Its Application for Sorption of Oxytetracycline from Aqueous Solution

Physicochemical characteristics of biochar and its sorption potential for oxytetracycline (OTC) were investigated. Biochars from pineapple peel waste were produced via pyrolysis under oxygen-depleted conditions at 350 °C (BL350), 500 °C (BL500), and 650 °C (BL650), as well as the characteristics and polycyclic aromatic hydrocarbons contents of the samples were compared. The sorption kinetics of OTC onto the biochars was completed in three stages, i.e., a fast stage, a slow stage, and an equilibrium stage after 24 h. The kinetics data were perfectly fitted by the pseudo-second-order model with high correlation coefficients (R2 > 0.999). All of the sorption isotherms were nonlinear and well described by the Langmuir model. The Langmuir maximum sorption capacity (qmax) increased in the order of BL650 > BL500 > BL350. The thermodynamic parameters revealed that the sorption of OTC onto the biochars was spontaneous and endothermic. Fourier transform infrared spectroscopy (FTIR) of the biochars before and after sorption of OTC confirmed that the H-bonding interaction was the dominant sorption mechanism. The results demonstrated that biochars obtained from inexpensive and renewable materials could be utilized as a highly effective and environmentally friendly adsorbent for removing organic contaminants from wastewater

Insertion Performance Study of an Inductive Weft Insertion System for Wide Weaving Machines

Wide weaving machines traditionally enhance the weaving width by increasing the shuttle’s initial velocity. However, this approach introduces challenges like pronounced equipment vibration, elevated noise levels, heightened energy consumption, and a reduced lifespan. Moreover, its efficacy in significantly widening fabric is constrained. Addressing these concerns, this paper proposes a wide-width warp insertion solution that involves driving the high-temperature superconducting shuttle to achieve high-speed horizontal flight through a traveling magnetic field. The inductive weft insertion system structure of wide weaving machines comprises an insertion guideway with an iron core and wound electromagnetic coils. The shuttle consists of a high-temperature superconducting block and a conductive plate, serving as the driving element. By establishing the equivalent circuit of the weft insertion guideway and the suspended shuttle, the calculation formula for the dynamic driving performance of the weft insertion guideway is obtained. Utilizing a transient 3D magnetic field simulation model, the impact of parameters like the current frequency, shuttle conductive plate thickness, and suspension gap on weft insertion performance is explored. Successful wide-width weft insertion motion is achieved by controlling coil input current parameters. Finally, an experimental platform is constructed to validate the correctness of the weft insertion system structure and simulation model through practical experiments

Updated estimation of forest biomass carbon pools in China, 1977-2018

China is one of the major forest countries in the world, and the accurate estimation of its forest biomass carbon (C) pool is critical for evaluating the country's C budget and ecosystem services of forests. Although several studies have estimated China's forest biomass using national forest inventory data, most of them were limited to the period of 2004-2008. In this study, we extended our estimation to the most recent period of 2014-2018. Using datasets of eight inventory periods from 1977 to 2018 and the continuous biomass expansion factor method, we estimated that the total biomass C pool and average biomass C density in Chinese forests increased from 4717 Tg C (1 Tg = 10(12) g) in the period of 1977-1981 to 7975 Tg C in the period of 2014-2018 and 38.2 Mg C ha(-1) to 45.8 Mg C ha(-1) (1 Mg = 10(6) g), respectively, with a net increase of 3258 Tg C and an annual sink of 88.0 Tg C yr(-1) . Over the most recent 10 years (20092018), the average national forest biomass C density and C sink were 44.6 Mg C ha(-1) and 154.8 Tg C yr(-1) , respectively, much larger than those of 39.6 Mg C ha(-1) and 63.3 Tg C yr(-1) in the period 1977-2008. These pronounced increases were largely attributed to afforestation practices, forest growth, and environmental changes. Our results have documented the importance of ecological restoration practices, provided an essential basis for assessing ecosystem services, and helped to achieve China's C neutrality target