Publications by authors named "Dagang Liu"

Polyelectrolyte-based ionic-junction fibers newly serve as signal transmission and translation media between electronic devices and biological systems, facilitating ion transport within organic matrices. In this work, we fabricated gel filaments of carboxymethyl cellulose (CMC) chelated with Cu(II) ions through wet-spinning, using a saturated coagulant of CuSO. Interestingly, the as-spun fibers exhibited dramatic 3D porous frameworks that varied with the temperature and precursor concentration.

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Biological polysaccharides such as cellulose, chitin, chitosan, sodium alginate, etc., serve as excellent substrates for 3D printing due to their inherent advantages of biocompatibility, biodegradability, non-toxicity, and absence of secondary pollution. In this review we comprehensively overviewed the principles and processes involved in 3D printing of polysaccharides.

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The alkali-free accelerator based on aluminum sulfate is widely used in shotcrete in tunnels. Long-term Ca-leaching of shotcrete may adversely affect the tunnels in a water-rich mountain. It is necessary to examine further the impact of the AS accelerator and / on cement hydration and leaching.

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Negatively surface-charged sulfate cellulose nanocrystals (CNCs) are always slowly self-assembled into left-handed cholesteric mesophases. In this work, macroscopic spiral patterns induced by counterclockwise vortex flowing or chiral doping were investigated. Results show that iridescent patterns of the arithmetic spiral, rose spiral, or latitude ripples were generated under the vortex rotation, indicating a severe microphase separation of CNCs.

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As an eco-friendly sustainable iridescent coating, cholesteric cellulose nanocrystal (CNC) is susceptible to substrate effects or shearing effects. In this work, interface interaction and liquid crystal phase transition were evaluated for fabricating iridescent cast or shear coatings of CNCs onto substrates of polystyrene, glass, ceramic, wood, stainless steel, metal, or metal alloy. Three types of substrate effects and four categories of shearing effects on the structure color mechanism of CNC coatings were proposed.

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A large body of data has confirmed that α7 nicotinic acetylcholine receptors (nAChRs) play a pivotal role in cognition, memory, and other neuropsychiatric diseases, but their effect on seizure susceptibility in C57BL/6 wild-type mice is not fully understood. Here, we showed that decreased activity of α7 nAChRs could increase the excitability of CA1 pyramidal neurons and shorten the onset time of epilepsy in pilocarpine-induced mouse models. However, compared with the control group, there was no apparent effect of increasing the activity of α7 nAChRs.

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A mechanical disintegration of waste wood biomass and freeze-induced assembly of colloidal nanowood were effectively deployed to explore ion-associated cellular foams (NWFs) with unidirectional channels. Under the assistance of inorganic ions, the as-fabricated foams were significantly enhanced in physical stability, compressive strength, flame retardancy, and thermal barrier, accounting for the tuning effects of pores and channels, surface charges, and microphase interaction by ion effects and freeze orientation. As a result, the vascular-like ion-doped channels benefited from quick capillary liquid transport.

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The cement-based grouting materials used for practical purposes in high-geothermal tunnels are inevitably affected by humidity and high temperature, leading to the deterioration of mechanical properties. Based on the characteristics of changing high temperatures and two typical conditions of hot-humid and hot-dry environments in high-geothermal tunnels, many mechanical strength tests were carried out on the grouting material cured under different environmental conditions. The study results indicated that high temperature and low relative humidity were unfavorable to the development of mechanical characteristics of grouting material, but the coupling effect of two factors could improve the strength at early ages and reduce the degradation of long-term strength.

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Cellulose nanocrystals (CNCs) per their twisting structure and high aspect ratio and charged surface property are increasingly receiving great attention in chiral photonic crystal and pigment fabrication. However, the cholesteric mesophases of CNCs is unstable and easily destroyed by the additives with high M. In this work, hydroxypropyl cellulose (HPC) and carboxymethyl cellulose (CMC) are incorporated into CNCs for a continuous mesophase transition monitoring.

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Polycationic chitosan has a strong coordination to heavy metal ions due to its multifunctional hydroxyl and amino groups. However, due to the fast and facile dissolution of chitosan in acidic medium, it is difficult to measure the exact adsorption amount or coordination capacity accurately. In this work, a simple method of lyophilization plus ethanol-washing was employed to separate and purify chitosan/Cr(III) complex for further determining the coordination capacity.

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Objective: In the study, we aimed to identify key microRNAs (miRNAs) and clinical factors associated with survival time of lower-grade glioma (LGG) and develop an expression-based miRNA signature to provide survival risk prediction for patients with LGG.

Methods: We obtained miRNA expression profiles and clinical information of patients with LGG from The Cancer Genome Atlas dataset. All 591 miRNAs were modeled using random Forest Survival, Regression, and Classification to construct a random forest model for survival analysis, and feature selection was performed.

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HO hydrolysis of mechanically-defibrillated chitin nanofibrils was explored as a green way of fabricating rod-like chitin nanocrystals (HO-hydrolyzed CHNs) that have an average length of 350 nm and width of 40 nm. We investigated the structure and morphology of CHNs as well as the rheology and lyotropic self-assembly behavior of its colloidal dispersions. The results show that although HO-hydrolyzed CHNs maintained the crystalline structure of α-chitin, surface charge of the nanorods was switched from positive to negative.

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Sulfate cellulose nanocrystal (CNC) dispersions always present specific self-assembled cholesteric mesophases which is easily affected by the inherent properties of particle size, surface charge, and repulsion or affinity interaction, and external field force generated from ionic potential of added electrolytes, magnetic or electric field, and mechanical shearing or stretching. Aiming at understanding the liquid crystal orientation and fiber alignment under high-voltage electric field, randomly distributed, uniform-aligned, or core-sheath nanofibrous mats involving charged CNCs and PVA were electrospun; and among them, specific straight arrayed fine nanofibers with average diameter of 270 nm were manufactured by using a simple and versatile gap collector. Moreover, arrayed composite nanofibers regularly aligned along the vertical direction of gap plates and selectively reflected frequent and continuous birefringence which was regarded as nematic phases of CNCs induced by the uniaxial stretching under high-voltage electric field.

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In order to promote sustainable development, green and renewable clean energy technologies continue to be developed to meet the growing demand for energy, such as supercapacitor, fuel cells and lithium-ion battery. It is urgent to develop appropriate nanomaterials for these energy technologies to reduce the volume of the device, improve the efficiency of energy conversion and enlarge the energy storage capacity. Here, chitosan/cellulose carbon cryogel (CCS/CCL) were designed and synthesized.

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With the increasing demand of environmental monitoring for toxic and odorous ammonia gas it is desired to develop specific green, cost-effective and in situ passive colorimetric alternatives to current complex instrumentations. In this work, we designed an ammonia gas sensor based on cholesteric liquid crystal films of copper(II)-doped cellulose nanocrystals (CNCCu(II)) whose structure, optical and sensing properties were investigated. The hybrid films using the low doping Cu(II) as a color-tuning agent inherited the chiral nematic signature and optical activity of CNCs, suggesting a strong chelation between copper ions and negatively charged CNCs.

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Colloidal cellulose nanocrystals were LBL deposited to form firmly-stacked optical coatings in which the nanorods regulated their head-to-tail association and aligned in the axial-centrifuged direction. The periodically transition from blue to orange of reflected colors was tunable via deposition layer adjustment. While the sensing coating was exposed to vapors of NHHO, HO, HCl and HAc, respectively, the color variation in the response process was irreversible at room temperature and highly dependent on vapor diffusion and chemical interface interaction.

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Microfibrillar biochars of chitin (CTF), chitosan (CSF), and cellulose (CLF) were fabricated via green homogenization and a pyrolysis process, and were subsequently explored as adsorbents for removing over-released sodium benzoate (SB) in aqueous systems. The structure, composition, morphology, and adsorption behavior of the as-fabricated biochars were characterized. Results suggest that all biochars, with a microscaled fibrillar structure and foam-like network morphology, underwent severe chemical transition during the pyrolysis process, thereby causing an enhancement of the Brunauer-Emmett-Teller surface area, pore volume, and aromatic and carbonaceous composition.

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Phosphate (PO) removal on calcite often entails two processes: adsorption and precipitation. Separating these two processes is of great importance for assessment of PO stability after removal. Thus, this study was aimed at finding a critical range of conditions for separating these two processes in calco-carbonic equilibrium, by adjusting PO concentration, reaction time and pH.

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The broad utility as an environmentally friendly and colorful coating of cellulose nanocrystal (CNC) was limited by its instability of coloration, brittleness, and lack of adhesion to a hydrophobic surface. In the present work, a neutral polymer, poly(ethylene glycol) (PEG) was introduced into CNC coatings through evaporation-induced self-assembly (EISA) on polymer matrices. The structure-color and mechanical properties of the composite coating or coating film were characterized by UV-vis spectroscopy, polarized light microscopy (PLM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WXRD), and tensile tests.

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A novel graphene oxide/chitin nanofibrils (GO-CNF) composite foam as a column adsorbent was prepared for aqueous contaminant disposal. The structures, morphologies and properties of composite foams supported by nanofibrils were characterized. As a special case, the adsorption of methylene blue (MB) on GO-CNF was investigated regarding the static adsorption and column adsorption-desorption tests.

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Batch methods were deployed to study the removal of phosphate by calcite in an open-system. Results showed that: (1) The pre-equilibrium process of calcite in open system could be achieved within 24 hours (2) The kinetic results showed that, at initial concentration of 0.5 mg · L⁻¹, the phosphate removal was almost completed within 10 hours of the first phase.

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The rigidity and low strain of chitosan fibers hindered their broader utility for biomedical applications. In present work, formic acid was employed as an efficient modifier for chitosan to prepare flexible fibers wet-spun from the formic acid modified chitosan solution. The formation of amide linkages between chitosan and formic acid was confirmed by FTIR, (13)C NMR, (1)H NMR and XRD measurements.

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The batch sorption methods were deployed to study the sorpti of p-phthalate on calcite in open-system. Results show that: (1) The o-phthalate sorption reached the equilibrium within 3 hours. Both pseudo first-order and pseudo second-order models described the kinetic characteristics well; (2) The o-phthalate sorption rate decreased with pH (7.

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In order to capture savings in energy and ambitious environmental targets, biodegradable composite foams of poly(vinyl alcohol) (PVA) supported by cellulose nanofibrils (CNF) were prepared through unidirectional freeze-drying technology. Effects of the content of CNF, the solid content of the precursor suspension, and the quenching temperature on the microstructure and properties of the composite foams were investigated by scanning electron microscopy (SEM), compressive testing, X-ray diffraction (XRD) analysis, water uptake, and biodegradation tests. Results show that the incorporation of CNF preferably at a weight ratio of 30 wt % greatly enhanced the mechanical strength and modulus, energy absorption, water resistance, and dimensional stability of the composite foams because of the rigid and semicrystalline nature of CNF as well as regular and compact pore structures.

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