Performance and characterization of phenol-formaldehyde resin with crude bio-oil by model compound method.

In order to clarify the effects of crude bio-oil for phenol-formaldehyde resin, the phenol-formaldehyde resin with bio-oil model compounds (BMPF) were prepared by model compound method. The bonding strength and aging resistance of BMPF were determined, and their microstructure and chemical bonds were also analyzed by scanning electron microscope, Fourier transform infrared spectroscopy, and nuclear magnetic resonance analysis, respectively. The results showed that the components of crude bio-oil had various degrees of effects on the BMPF performance, and the most obvious one is the phenols. The phenols and the ketones of bio-oil had positive effects on the bonding strength. The ketones had the biggest effect on the surface smoothness of BMPF film. But all components of bio-oil could inordinately improve the aging resistance of BMPF. The structural analysis indicated that the effects of bio-oil components on the BMPF performance by changing the resin structure. The CH2 peak in FT-IR and the methylene bridges intensity in NMR of phenol-free BMPF and ketone-free BMPF were smaller, while the results of aldehyde-free BMPF and acid-free BMPF were opposite. And the influence degree of BMPF structure was basically consistent with that of BMPF performance. These results could provide a basis for the modification of phenol-formaldehyde resin by crude bio-oil.

Gluconeogenesis Alteration and p53-SIRT6-Fox01 Signaling Adaptive Regulation in Sheep from Different Grazing Periods.

The decline in sheep health and meat quality caused by seasonal nutritional deficiencies has always been an important problem in the production of naturally grazing sheep. Glucose metabolism is crucial in ruminants for adequate cell function and maintenance of the body tissues and systems. However, whether glucose metabolism, especially gluconeogenesis, is affected by seasonal grazing conditions has not been fully uncovered. Thus, twelve sheep from two seasons (dry and green grass periods) in natural grazing areas of Inner Mongolia, China, were selected for this study. Their serum glucose, insulin, PC, and PEPCK levels and volatile fatty acid (gluconeogenesis material) concentrations in rumen fluid were analyzed. The expression of key enzymes including PC, PEPCK, GLUT2, and G6P of gluconeogenesis and their regulators INSR, PI3K/AKT and p53-SIRT6-Fox01 in the liver was detected by real-time PCR and western blotting. The results revealed significant variances in gluconeogenesis and its indicators and showed p53-SIRT6-Fox01 as having potential regulation in different grazing periods. This study offers new insights into the mechanism of gluconeogenesis and adaptive regulation between dry grass period and green grass period and also provides a reference for maintaining the health of sheep and meat quality despite seasonal nutritional deficiencies.

Aging Behaviors of Phenol-Formaldehyde Resin Modified by Bio-Oil under Five Aging Conditions.

The bio-oil phenol-formaldehyde (BPF) resin, prepared by using bio-oil as a substitute for phenol, has similar bonding strength but lower price to phenol-formaldehyde (PF) resin. As a common adhesive for outdoor wood, the aging performance of BPF resin is particularly important. The variations in mass, bonding strength, microstructure, atomic composition, and chemical structure of BPF resin under five aging conditions (heat treatment, water immersion, UV exposure, hydrothermal treatment, and weatherometer treatment) were characterized by scanning electron microscope, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy, respectively. Compared under five aging conditions, after aging 960 h, the mass loss of plywood and film was largest under hydrothermal treatment; the bonding strength of plywood, the surface roughness, and O/C ratio of the resin film changed most obviously under weatherometer treatment. FT-IR analysis showed that the decreased degree of peak intensity on CH2 and C-O-C characteristic peaks of BPF resin were weaker under water immersion, hydrothermal treatment, and weatherometer treatment than those of PF resin. The comparison of data between BPF and PF resins after aging 960 h showed that adding bio-oil could obviously weaken the aging effect of water but slightly enhance that of heat. The results could provide a basis for the aging resistance modification of BPF resin.

Preparation and Characterization of Bio-oil Phenolic Foam Reinforced with Montmorillonite.

Introducing bio-oil into phenolic foam (PF) can effectively improve the toughness of PF, but its flame retardant performance will be adversely affected and show a decrease. To offset the decrease in flame retardant performance, montmorillonite (MMT) can be added as a promising alternative to enhance the flame resistance of foams. The present work reported the effects of MMT on the chemical structure, morphological property, mechanical performance, flame resistance, and thermal stability of bio-oil phenolic foam (BPF). The Fourier transform infrared spectroscopy (FT-IR) result showed that the -OH group peaks shifted to a lower frequency after adding MMT, indicating strong hydrogen bonding between MMT and bio-oil phenolic resin (BPR) molecular chains. Additionally, when a small content of MMT (2-4 wt %) was added in the foamed composites, the microcellular structures of bio-oil phenolic foam modified by MMT (MBPFs) were more uniform and compact than that of BPF. As a result, the best performance of MBPF was obtained with the addition of 4 wt % MMT, where compressive strength and limited oxygen index (LOI) increased by 31.0% and 33.2%, respectively, and the pulverization ratio decreased by 40.6% in comparison to BPF. These tests proved that MMT can blend well with bio-oil to effectively improve the flame resistance of PF while enhancing toughness.

Noble Metal-Free Photocatalysts Consisting of Graphitic Carbon Nitride, Nickel Complex, and Nickel Oxide Nanoparticles for Efficient Hydrogen Generation.

A facile and simple synthetic route is developed to prepare earth-abundant and noble metal-free hybrid photocatalysts, which are composed of graphitic carbon nitride (CN), nickel complex, and NiO x nanoparticles. Bimolecular nucleophilic substitution reaction was employed to attach a nickel complex onto a graphitic CN framework through covalent bonds to support its high loading and dispersion. NiO x nanoparticles were further incorporated into the catalysts to serve as a hole-transporting medium to improve the separation of photogenerated carriers for higher photocatalytic activity. Both yNiL/CN and yNiL/NiO x/CN exhibit superb H2 evolution activity. The optimum H2 evolution rate of the binary photocatalysts yNiL/CN reaches 303.3 µmol·h-1·g-1, whereas that of the ternary photocatalysts yNiL/NiO x/CN reaches 524.1 µmol·h-1·g-1, and the apparent quantum efficiency reaches 1.46% at 450 nm. This finding reveals that coordination of a nickel complex is significant in promoting photocatalytic performance, and the incorporation of NiO x nanoparticles as a hole-transporting medium is beneficial for separation of the photogenerated charge carriers. The novel hybrid system offers a new horizon for designing transition-metal complex-modified graphitic CN as noble metal-free and highly active photocatalysts for efficient visible light-driven hydrogen generation.

Preparation and Characterization of Phenolic Foam Modified with Bio-Oil.

Bio-oil was added as a substitute for phenol for the preparation of a foaming phenolic resin (PR), which aimed to reduce the brittleness and pulverization of phenolic foam (PF). The components of bio-oil, the chemical structure of bio-oil phenolic resin (BPR), and the mechanical performances, and the morphological and thermal properties of bio-oil phenolic foam (BPF) were investigated. The bio-oil contained a number of phenols and abundant substances with long-chain alkanes. The peaks of OH groups, CH2 groups, C=O groups, and aromatic skeletal vibration on the Fourier transform infrared (FT-IR) spectrum became wider and sharper after adding bio-oil. These suggested that the bio-oil could partially replace phenol to prepare resin and had great potential for toughening resin. When the substitute rate of bio-oil to phenol (B/P substitute rate) was between 10% and 20%, the cell sizes of BPFs were smaller and more uniform than those of PF. The compressive strength and flexural strength of BPFs with a 10⁻20% B/P substitute rate increased by 10.5⁻47.4% and 25.0⁻50.5% respectively, and their pulverization ratios decreased by 14.5⁻38.6% in comparison to PF. All BPFs maintained good flame-retardant properties, thermal stability, and thermal isolation, although the limited oxygen index (LOI) and residual masses by thermogravimetric (TG) analysis of BPFs were lower and the thermal conducticity was slightly greater than those of PF. This indicated that the bio-oil could be used as a renewable toughening agent for PF.

Carbon nanotubes-modified graphitic carbon nitride photocatalysts with synergistic effect of nickel(II) sulfide and molybdenum(II) disulfide co-catalysts for more efficient H2 evolution.

This work reports effective photocatalysts which are composed of carbon nitride (CN), carbon nanotubes (CNTs), MoS2 and NiS, for hydrogen evolution aiming at energy crises and environmental pollutions. The morphologies and optical properties of the photocatalysts were carefully characterized and their photocatalytic performance towards water reduction was studied afterwards. MoS2 and NiS exhibit a significant synergistic effect working as co-catalysts. Compared to MoS2/CN nanohybrid, carbon nanotubes and NiS improved the absorption of visible light and the separation of charge carriers effectively. NiS-MoS2/CNTs/CN catalyst exhibits high performance for H2 evolution and the optimized rate is 309.9 µmol·h-1·g-1 with no noble metals under visible light irradiation. The study demonstrates a non-noble metal photocatalyst system for effective generation of hydrogen with low cost.

Aging Properties of Phenol-Formaldehyde Resin Modified by Bio-Oil Using UV Weathering.

The aging properties of phenol-formaldehyde resin modified by bio-oil (BPF) were analyzed using ultraviolet (UV) weathering. The variations on bonding strength of BPF were measured, and the changes on microstructure, atomic composition and chemical structure of BPF were characterized by using a scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR), respectively. With the increase of aging time, the bonding strength decreased gradually, the resin surface became rougher and the O/C radio of resin surface increased. However, the loss rate of bonding strength of BPFs was 9.6⁻23.0% lower than that of phenol-formaldehyde resin (PF) after aging 960 h. The aging degree of BPF surfaces was smaller in comparison to PF at the same aging time. These results showed that the bio-oil had a positive effect on the anti-aging property. Analytical results revealed that with increasing the aging time, the XPS peak area of C⁻C/C⁻H decreased, while that of C=O and O⁻C=O increased. The intensity of methylene and ether bridges in NMR analysis decreased along with increasing the intensity of aldehydes, ketones, acids and esters. These results indicated that the aging mechanism of BPF was a process of the breakage of molecular chains and formation of oxygen-containing compounds.

Alterations in epididymal proteomics and antioxidant activity of mice exposed to fluoride.

It is well known that high fluoride results in low fertility. Epididymis is the important place for spermatozoa maturation, which is essential for successful fertilization. In the previous studies, fluoride was reported to damage the epididymal structure of mouse and rabbit. However, the mechanism underlying sodium fluoride (NaF)-induced epididymal toxicity has not yet been well elucidated. The aim of this study is to explore the global protein alterations in epididymis of mice exposed to NaF using the iTRAQ technique. Results showed that 211 proteins were differentially expressed in both 25 and 100 mg/L NaF groups. Some of them have been proved to be important for reproduction, such as low-density lipoprotein receptor-related protein 2 (Lrp2), cytochrome c, testis-specific (Cyct), sorbitol dehydrogenase (Sord), glutathione S-transferases (GSTs), acrosin, beta-defensin 126, cysteine-rich secretory protein (Crisp) 1, and Crisp2. Gene ontology (GO) analysis suggested cellular process, organelle and catalytic activity account for high percent and number of differentially expressed proteins. 171 pathways were found after the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, among which the representative maps, such as ribosome, focal adhesion, and phagosome, were involved. Different functional categories post-translational modification, protein turnover, chaperones; translation, ribosomal structure and biogenesis; cytoskeleton; energy production and conversion are implicated in the Cluster of Orthologous Groups (COG) of proteins analysis. Subsequently, the effect of NaF on the antioxidant activity in epididymis, especially glutathione and glutathione-related enzymes, was evaluated. Results exhibited high fluoride caused low total antioxidant capacity (T-AOC), high methane dicarboxylic aldehyde (MDA), decreased reduced glutathione (GSH), and the glutathione-related enzymes [GSH peroxidase (GPx), GSH reductase (GR), and GSH S-transferase (GST)] changes in activity, protein, and mRNA expressions. In summary, NaF decreased the antioxidant activity of epididymis, especially glutathione and glutathione-related enzymes, as well as iTRAQ results, providing new explanations for the low sperm quality induced by fluoride.

Adding nickel formate in alkali lignin to increase contents of alkylphenols and aromatics during fast pyrolysis.

The composition of pyrolysis vapors obtained from alkali lignin pyrolysis with the additive of nickel formate was examined using the pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). Characterization of bio-chars was performed using X-ray diffraction (XRD). Results showed that the nickel formate significantly increased liquid yield, simplified the types of alkali lignin pyrolysis products and increased individual component contents. The additive of nickel formate increased contents of alkylphenols and aromatics from alkali lignin pyrolysis. With an increase in temperature, a greater amount of the relative contents can be achieved. The nickel formate was thermally decomposed to form hydrogen, resulting in hydrodeoxygenation of alkali lignin during pyrolysis. It was also found that Ni is in favor of producing alkylphenols. The analysis based on the experimental result provided evidences used to propose reaction mechanism for pyrolysis of nickel formate-assisted alkali lignin.