Production of xylooligosaccharides and monosaccharides from poplar by a two-step acetic acid and peroxide/acetic acid pretreatment

Abstract Background Populus (poplar) tree species including hybrid varieties are considered as promising biomass feedstock for biofuels and biochemicals production due to their fast growing, short vegetative cycle, and widely distribution. In this work, poplar was pretreated with acetic acid (AC) to produce xylooligosaccharides (XOS), and hydrogen peroxide–acetic acid (HPAC) was used to remove residual lignin in AC-pretreated poplar for enzymatic hydrolysis. The aim of this work is to produce XOS and monosaccharides from poplar by a two-step pretreatment method. Results The optimal conditions for the AC pretreatment were 170 °C, 5% AC, and 30 min, giving a XOS yield of 55.8%. The optimal HPAC pretreatment conditions were 60 °C, 2 h, and 80% HPAC, resulting in 92.7% delignification and 87.8% cellulose retention in the AC-pretreated poplar. The two step-treated poplar presented 86.6% glucose yield and 89.0% xylose yield by enzymatic hydrolysis with a cellulases loading of 7.2 m/g dry mass. Very high glucose (93.8%) and xylose (94.6%) yields were obtained with 14.3 mg cellulases/g dry mass. Both Tween 80 and β-glucosidase enhanced glucose yield of HPAC-pretreated poplar by alleviating the accumulation of cellobiose. Under the optimal conditions, 6.9 g XOS, 40.3 g glucose, and 8.9 g xylose were produced from 100 g poplar. Conclusions The AC and HPAC pretreatment of poplar represented an efficient strategy to produce XOS and fermentable sugars with high yields. This two-step pretreatment was a recyclable benign and advantageous scheme for biorefinery of the poplar into XOS and monosaccharides

Wheat yield convergence and its driving factors in countries along the Belt and Road

Improving the wheat yield of countries along the Belt and Road (BR) plays a core role in ensuring global food security. However, little attention has been paid to the wheat yield variation and the determinants across these countries. This paper analyzes wheat yield convergence in countries along the BR using the club-convergence test. The empirical results show that instead of one convergence for all countries along the BR, the wheat yields are converging into three clubs. Furthermore, we investigate the impact of climate change and agricultural production technology on wheat yield convergence, and find that countries along the BR with a one degree Celsius increase in temperature are 36.5% (32.7%) more likely to converge to the high-level yield club. This may be related to the lower frequency of frost and higher photosynthetic capacity of wheat. We also find that a one kilogram increase in fertilizer application per hectare will result in a 0.4% (0.5%) higher probability of countries along the BR converging to the high-level yield club. Countries along the BR should pay more attention to coordinating production technologies and climate change to ensure food security

Bipolar resistive switching behaviors of ITO nanowire networks

We have fabricated indium tin oxide (ITO) nanowire (NW) networks on aluminum electrodes using electron beam evaporation. The Ag/ITO-NW networks/Al capacitor exhibits bipolar resistive switching behavior. The resistive switching characteristics of ITO-NW networks are related to the morphology of NWs. The x-ray photoelectron spectroscopy was used to obtain the chemical nature from the NWs surface, investigating the oxygen vacancy state. A stable switching voltages and a clear memory window were observed in needle-shaped NWs. The ITO-NW networks can be used as a new two-dimensional metal oxide material for the fabrication of high-density memory devices

Cobalt-Based Metal-Organic Framework Nanoparticles with Peroxidase-like Catalytic Activity for Sensitive Colorimetric Detection of Phosphate

Appropriate addition of phosphate salt in food can improve the food quality and taste. However, extensive intake of phosphate salt may lead to some human diseases such as hyperphosphatemia and renal insufficiency. Thus, it is essential to establish a cost-effective, convenient, sensitive, and selective method for monitoring phosphate ion (Pi) to ensure food quality control. In this work, a Co-based metal-organic frameworks (Co-MOF) nanomaterial with dual functions (peroxidase-like activity and specific recognition) was designed for acting as a catalytic chromogenic platform for sensitive detection of Pi. The Co2+ nodes not only provide high enzyme-like activity to catalyze the 3,3′,5,5′--tetramethylbenzidine (TMB) substrate to blue oxTMB (652 nm) but also act as selective sites for Pi recognition. The use of cationic organic ligands (2-methylimidazole) and cationic metal ions (Co2+) endows the Co-MOF with a strong positive surface charge, which is beneficial to the capture of negative-charged Pi and the dramatically suppressed TMB oxidation. When Pi exists, it specifically adsorbs onto the Co-MOF through the Co-O-P bond and the strong electrostatic interaction, leading to the change of surface charge on Co-MOF. The peroxidase-like catalytic activity of Co-MOF is thus restrained, causing a different catalytic effect on TMB oxidation from that without Pi. Based on this principle, a colorimetric assay was established for rapid and sensitive detection of Pi. A good linear relationship was obtained between Pi concentration and the absorbance at 652 nm, with a linear range of 0.009–0.144 mg/L and a detection limit of 5.4 μg/L. The proposed assay was applied to the determination of Pi in actual food samples with recoveries of 92.2–108% and relative standard deviations (RSDs) of 2.7–7.3%, illustrating the promising practicality for actual samples analysis

Effect of exogenous trivalent iron ions on tau phosphorylation and aggregation in SH-SY5Y cells

BackgroundA large amount of iron deposition in the brain can cause neuronal damage by inducing oxidative stress, neuroinflammation, and abnormal mitochondrial function. In addition, iron deposition is also reported to be closely related to the pathogenesis of Alzheimer's disease (AD). The neurofibrillary tangles aggregated by tau hyperphosphorylation are one of the important pathological features of AD. ObjectiveTo investigate potential effect of exogenous trivalent iron ions on neuronal activity in human neuroblastoma (SH-SY5Y) cells and tau hyperphosphorylation and aggregation. MethodsSH-SY5Y cells were treated with ferric chloride (FeCl3) at four concentrations (10, 100, 200, and 400 mg·L−1). Cell survival rate was then detected by CCK8 assay. Intracellular iron content was determined prussian blue (Perl's) by iron staining after 24 h exposure to FeCl3 at 10 or 200 mg·L−1. Transfection of tau-P301L plasmid was conducted to construct an AD-like cell model for tau overexpression. The differences in the expression of the phosphorylated tau (p-tau) protein in SH-SY5Y cells and SH-SY5Y cells with tau overexpression were detected by Western blotting after 24 h exposure to FeCl3 at 10 and 200 mg·L−1. After dilution with phosphate buffered saline (PBS), FeCl3, human tauR3, and FeCl3 + tauR3 were incubated at 37℃, and the fluorescence intensity reflecting tau aggregation level was measured by thioflavin T(ThT) method at 12, 24, 36, 48, 60, 72, 84, and 96 h, respectively. Meanwhile, after 96 h coincubation of FeCl3 and tauR3, the fibers formed by tau aggregation were observed under a transmission electron microscope (TEM). ResultsAfter 24 h of FeCl3 exposure, the cell survival rate of SH-SY5Y cells among all groups was statistically different (F=8.63, P<0.01). The cell survival rates in the 200 and 400 mg·L−1 groups were 80.1% and 68.7% of the control group, respectively (P<0.05). Compared with the control group, the nuclei of the 200 mg·L−1 FeCl3 group were mainly yellowish-brown after iron staining and the positive cell rate was up-regulated by 12.9% (P<0.01). After 24 h of FeCl3 exposure , the p-tau (Ser396) protein expression was statistically different among all groups (F=11.6, P<0.01). Compared with the control group, the p-tau protein expression level of SH-SY5Y cells in the 200 mg·L−1 group was up-regulated by 72.7% (P<0.01). After FeCl3-treated SH-SY5Y cells with tau overexpression for 24 h, the p-tau (Ser396) protein expression was statistically different among all groups (F=27.8, P<0.01). Compared with the tau group, the p-tau (Ser396) protein expression level of SH-SY5Y cells in the tau + 200 mg·L−1 group was up-regulated by 44.6% (P<0.05). Compared with the tauR3 group, the fluorescence intensities in the 84 and 96 h tauR3 + FeCl3 groups were up-regulated by 49.9% and 53.7% (P<0.01) respectively. After 96 h of coincubation, compared with the tauR3 group, FeCl3 + tauR3 aggravated tau aggregation and formed fiber deposition under TEM. ConclusionExogenous trivalent iron ions may inhibit SH-SY5Y cell viability, promote the phosphorylation of tau in SH-SY5Y cells transfected with tau-P301L plasmid, and aggravate tauR3 aggregation and fiber production

<i>Chroogomphus rutilus</i> Regulates Bone Metabolism to Prevent Periodontal Bone Loss during Orthodontic Tooth Movement in Osteoporotic Rats

Osteoporosis (OP) leads to the acceleration of tooth movement and aggravation of periodontal bone loss during orthodontic treatment. Chroogomphus rutilus (CR) is abundant in nutrients and demonstrates remarkable antioxidant and anti-inflammatory properties. In the present study, the components of CR, including 35.00% total sugar, 0.69% reducing sugar, 14.40% crude protein, 7.30% total ash, 6.10% crude fat, 0.51% total flavonoids, 1.94% total triterpenoids, 0.32% total sterol, 1.30% total saponins, 1.69% total alkaloids, and 1.02% total phenol, were first systematically examined, followed by an investigation into its regulatory effects on bone metabolism in order to mitigate bone loss during orthodontic tooth movement in osteoporotic rats. The results of the imaging tests revealed that CR treatment reduced periodontal bone loss and normalized tooth movement in the OP. In conjunction with analyses of intestinal flora and metabolomics, CR enhances the prevalence of anti-inflammatory genera while reducing the production of inflammatory metabolites. Meanwhile, CR reduced the levels of periodontal inflammatory factors, including TNF-α, IL-1β, and IL-6, by activating Wnt/β-catenin signaling, and promoted periodontal bone formation. These findings imply that CR is a potent supplementary therapy for controlling periodontal bone remodeling in patients with OP undergoing orthodontic treatment

Hyaluronic Acid (HA)-Based Silk Fibroin/Zinc Oxide Core–Shell Electrospun Dressing for Burn Wound Management

Contains fulltext : 220438.pdf (Publisher’s version ) (Closed access)Burn injuries represent a major life-threatening event that impacts the quality of life of patients, and places enormous demands on the global healthcare systems. This study introduces the fabrication and characterization of a novel wound dressing made of core-shell hyaluronic acid-silk fibroin/zinc oxide (ZO) nanofibers for treatment of burn injuries. The core-shell configuration enables loading ZO-an antibacterial agent-in the core of nanofibers, which in return improves the sustained release of the drug and maintains its bioactivity. Successful formation of core-shell nanofibers and loading of zinc oxide are confirmed by transmission electron microscopy, Fourier-transform infrared spectroscopy, and energy dispersive X-ray. The antibacterial activity of the dressings are examined against Escherichia coli and Staphylococcus aureus and it is shown that addition of ZO improves the antibacterial property of the dressing in a dose-dependent fashion. However, in vitro cytotoxicity studies show that high concentration of ZO (>3 wt%) is toxic to the cells. In vivo studies indicate that the wound dressings loaded with ZO (3 wt%) substantially improves the wound healing procedure and significantly reduces the inflammatory response at the wound site. Overall, the dressing introduced herein holds great promise for the management of burn injuries