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The generation of pseudo-lignin as byproduct during the lignocellulose acidic pretreatment has been proposed for many years. However, the detailed formation mechanism is still unclear. Moreover, there is a lack of understanding in the initial reaction during the formation of humins (byproducts in furfural production) and acid-induced hydrothermal carbon (carbon material). In this work, the initial formation of these three substances were investigated. We first found the common feature of their formation process was that carbohydrate-hydrolyzed compounds could form black polymers by condensing in acidic media, but the difference was dependent on the reaction degree. Furthermore, the results revealed that oxidation was an accelerator for condensations during producing black polymers because oxidized compounds could enhance the acidity of the reaction system. However, condensations of oxidized compounds were more difficult to proceed. Meanwhile, during the initial stage, the dominating pathway was that furfural condensed with itself and isomerized xylose via aldol-condensation.

This work describes an all-biomass fluorescent hydrogel fabricated by functionalizing alginate (ALg) and cellulose nanofibers (CNF) hydrogels with fluorescent biomass carbon dots (CQDs) derived from glucose, xylose, and glucosamine. The biomass CQDs played dual functions in the composite hydrogels: first, endowing hydrogels with good fluorescent characters; second, enhancing the mechanical properties of hydrogels because of the cross-linking effect of the abundant oxygen-containing groups or amino groups on surface with ALg or CNF. The elastic modulus of ALg hydrogel and CNF hydrogel was increased by 4.7 times and 1.5 times, respectively, by the adding CQDs. As a proof of concept, ALg/CQDs-3 hydrogel and CNF/CQDs-3 hydrogel were used to detect Fe

Formaldehyde is a colorless, highly toxic, and flammable gas that is harmful to human health. Recently, many efforts have been devoted to the application of activated carbon to absorb formaldehyde. In this work, lignocellulose-based activated carbon fiber paper (LACFP) loaded with manganese dioxide (MnO2) was fabricated for the adsorption and in-situ catalytic degradation of formaldehyde. LACFP was prepared by two-stage carbonization and activation of sisal hemp pulp-formed paper and was then impregnated with manganese sulfate (MnSO4) and potassium permanganate (KMnO4) solutions; MnO2 then formed by in situ growth on the LACFP base by calcination. The catalytic performance of MnO2-loaded LACFP for formaldehyde was then investigated. It was found that the suitable carbonization conditions were elevating the temperature first by raising it at 10°C/min from room temperature to 280°C, then at 2°C/min from 280 to 400°C, maintaining the temperature at 400°C for 1 h, and then increasing it quickly from 400 to 700°C at 15°C/min. The conditions used for activation were similar to those for carbonization, with the temperature additionally being held at 700°C for 2 h. The conditions mentioned above were optimized to maintain the fiber structure and shape integrity of the paper, being conducive to loading with catalytically active substances. Regarding the catalytic activity of MnO2-loaded LACFP, the concentration of formaldehyde decreased by 59 ± 6 ppm and the concentration of ΔCO2 increased by 75 ± 3 ppm when the reaction proceeded at room temperature for 10 h. The results indicated that MnO2-loaded LACFP could catalyze formaldehyde into non-toxic substances.

Recently, ever-increasing focus has been on the exploration of high-strength and intelligent hydrogels. In this paper, we demonstrate a feasible approach to prepare magnetic hydrogels with high compression strength, elasticity and elongation by a two-step process. Quaternized xylan (QXH) and cellulose nanocrystal (CNC) could form the ionic crosslinking within the network to enhance the mechanical strength of hydrogels. Subsequently, Fe3O4 nanoctahedra was fabricated in situ within the reinforced hydrogel matrix. Properties of prepared hydrogels including the compressive strength, swelling ratio, magnetic performance, thermal stability, surface morphology and adsorption capacity for heavy metal ions from the aqueous solution were investigated. Results showed that QXH and CNC had the significant impact on improving the strength property of hydrogels. The compressive stress of prepared hydrogel was sharply increased to the limit of the measurement (2.5 MPa), when the compressive strain reached 85%. This hydrogel also maintained 90% original strength after compression for 30 times. The maximum tensile elongation of this hydrogel was 2875%, corresponding to the breaking tensile strength of 73.86 kPa. Prepared hydrogels also showed the good absorption capacity for heavy metal ions.

BACKGROUND: The cost of using cellulase to effectively release fermentable sugars from lignocellulosic substrates is still a major impediment to development of the enzyme‐based ‘biorefinery’ industry. This study attempted to optimize a cellulase preparation from on‐site fermentation to efficiently hydrolyse atmospheric glycerol organosolv (AGO)‐pretreated wheat straw. RESULTS: Addition of Cu²⁺, PEG10000, L‐ascorbic acid and trehalose in the fermentation medium significantly improved the cellulase production. Use of all the additives enabled enhancement to 45.5% of filter paper cellulase (FPA), 14.7% of β‐glucosidase (BG) and 32.4% of carboxymethyl cellulase (CMCase). With the on‐site production of crude cellulase, accessory enzymes (β‐glucosidase (BG), xylanase and lysozyme) and additives (tea saponin (TS) and cationic polyacrylamide (c‐PAM)) were found to facilitate the hydrolysis of AGO‐pretreated substrates effectively. The optimized cellulase mixture allowed 96% of enzymatic hydrolysis at 5 FPU g‐¹ for 48 h on addition of 11.5 U g‐¹ BG, 180 U g‐¹ xylanase, 45 U g‐¹ lysozyme, 10 mg g‐¹ TS and 2 mg g‐¹ C‐PAM, which was twice that of the crude cellulase broth. CONCLUSION: Cellulase customization for specific substrate hydrolysis with on‐site produced broth produced an efficient pathway to lower the enzyme cost in the ongoing lignocellulosic biorefining industry. © 2018 Society of Chemical Industry

As a highly abundant natural and renewable aromatic polymer, lignin has been proven to be a good UV-absorber and natural broad-spectrum sun blocker. The structure-activity relationship of lignin under UV radiation remains unclear due to lignin’s complexity and heterogeneity. Here we report the structure influence of lignin on its anti-UV radiation properties of sun protection factor (SPF), UV absorbance, and antioxidant activity by using different lignin model compounds, including β–O–4, β–β, and β–5 dimers, etc., representing the structures of both native lignins and technical lignins. Meanwhile, UV protection properties of six lignin preparations, including cellulolytic enzyme lignin (CEL), organosolv lignin (OL), and kraft lignin (KL) of pinus kesiya and eucalyptus, were also evaluated for better comparison. SPF values of sunscreen preparations were increased but varied with the same addition of each single model compound into the pure cream or commercial sunscreen. In particular, the SPF value of the sunscreen has been greatly enhanced by the addition of a certain molar concentration of a single model compound (0.0558 mmol, around 2 wt%) into the low SPF commercial sunscreen, which was attributed to the synergistic effects of lignin models and inherent sunscreen agent. By comparing, lignin models containing β–O–4 linkage displayed the least desirable UV protection properties in this work, and side-chain difference, especially the existence of conjugate structure and carboxylic groups, would significantly impact the lignin model compounds’ UV performance. Additionally, the antioxidant activities and UV absorbance of different model compounds and lignin preparations are closely related to their structures. These insights revealed the structure-activity relationship of lignin under UV radiation and will provide a theoretical basis for optimizing lignins or lignin derivatives as the sun-screening agents in sunscreens.

Traditional preparation methods of the hydrogel are not only tedious but also requiring external stimuli. Here, a plant catechol-inspired self-catalytic system (sulfonated lignin and iron ion) has been introduced to rapidly trigger the graft polymerization of vinyl monomers on the carboxymethyl xylan (CMX) at room temperature, generating an elastic, UV-shield, and conductive hydrogel. The rapid preparation process can be finished at room temperature in 5 min without the removal of oxygen. The hydrogel shows charming extension ratio (up to 460%) and tensile stress (up to 23 kPa), which can be ascribed to the double network structure constructed from Fe3+ and CMX. The hydrogel exhibits great transparency (up to 85.37%), fascinating UV-blocking (up to 99%), and conductive features, thereby serving as potential human body sensors. The rapid preparation of xylan-derived hydrogels via dynamic lignin catechol chemistry may open up a new approach to high-valued utilization of biomass.

Torrefaction is a routine and effective method for recovering energy from biomass. In this study, autohydrolysis pretreatment was proposed to upgrade the torrefaction process of moso bamboo, and their relationship was evaluated. Results showed that about 80.24 % of bamboo hemicellulose were dissolved during autohydrolysis pretreatment. Compared with main chain, arabinan side chain of hemicellulose was much easier to be degraded, and more uniform hemicellulose could be obtained at 160 °C. The O/C values of autohydrolysis solid residues and the mass yield of torrefied bamboo decreased gradually with the enhancement of reaction severity (autohydrolysis and/or torrefaction), while the HHV values increased. The higher torrefaction temperature or autohydrolysis pretreatment severity was, the better thermostability of torrefied bamboo could be observed. 2D-HSQC of milled wood lignin revealed that autohydrolysis pretreatment can effectively accelerate the degradation of β-O-4 linkage in lignin and increase G-type lignin content during torrefaction process. Compared with direct torrefaction, prehydrolysis can greatly facilitate the torrefaction process and enhance the quality of final products.

The efficient production of xylose and arabinose from glucose, is significant but technologically challenging. Herein, the conversion of glucose to pentose (xylose and arabinose) and formic acid was realized using non-toxic artificial zeolite and green solvent of γ-butyrolactone-H2O. The selective conversion of glucose to 5-hydroxymethylfurfural, pentose and furfural could be regulated by controlling Bronsted acid strength. The weak Bronsted acid could promote the formation of pentose, while strong Bronsted acid could lead to the formation of HMF and further degradation of pentose to furfural. The mechanism was investigated spectroscopically to add fundamental insights to the selective C1-C2 bond cleavage. The solvent of γ-butyrolactone-H2O reduced apparent activation energy by promoting the formation of active d -fructofuranose. The favorable yield reached to 54.3 % pentose and 54.7 % formic acid from glucose, while 95.6 % pentose and 96.8 % formic acid from fructose at 453 K for 1.5 h. This strategy offered a new utilization way of glucose in expanding the varieties of platform chemicals.

Neuroblastoma is the most common extracranial solid childhood tumor. Despite the availability of advanced multimodal therapy, high-risk patients still have low survival rates. p21-activated kinase 4 (PAK4) has been shown to regulate many cellular processes in cancer cells, including migration, polarization and proliferation. However, the role of PAK4 in neuroblastoma remains unclear. In the present study, we demonstrated that PAK4 was overexpressed in neuroblastoma tissues and was correlated with tumor malignance and prognosis. To investigate the function of PAK4 in neuroblastoma, we used a small-molecule inhibitor that targets PAK4, that is, PF-3758309. Our results showed that PF-3758309 significantly induced cell cycle arrest at the G1 phase and apoptosis in neuroblastoma cell lines. Meanwhile, the inhibition of PAK4 by PF-3758309 increased the expression of CDKN1A, BAD and BAK1 and decreased the expression of Bcl-2 and Bax. In addition, we screened the target genes of PAK4 by PCR array and found that 23 genes were upregulated (including TP53I3, TBX3, EEF1A2, CDKN1A, IFNB1 and MAPK8IP2) and 20 genes were downregulated (including TNFSF8, Bcl2-A1, Bcl2L1, SOCS3, BIRC3 and NFKB1) after PAK4 inhibition by PF-3758309. Moreover, PAK4 was found to regulate the cell cycle and apoptosis via the ERK signaling pathway. In conclusion, the present study demonstrated, for the first time, the expression and function of PAK4 in neuroblastomas and the inhibitory effect of PF-3758309, which deserves further investigation as an alternative strategy for neuroblastoma treatment.

To overcome the recalcitrance of lignocellulose structures that hinders the robust bioconversion of biomass for bioethanol and lignin-coproduct productions, efficient approaches are needed to remove hemicelluloses. In this study, a microwave-induced hydrothermal pretreatment of corncob was developed to improve xylo -sugars (xylose, xylooligosaccharides and xylan) yields and to reduce the hemicelluloses loss by controlling NaOH and the severity factor. During this process, the severity factor ranged from 2.30 to 4.30 and the low concentration of NaOH below 0.32% were considered. The results showed that NaOH had a significant impact on xylo -sugars yields as well as the severity factor. The highest xylo -sugars yield of 88.71% was achieved when 0.005% NaOH was employed as the deacetylation agent and the severity factor was 4.00. Meanwhile, the unknown loss of hemicelluloses was limited to 1.51% (based on the total hemicelluloses in corncob) and the formation of furfural was also limited at the low level (1.72%).

This paper presents a general solution of precise position synchronous control for multi-axis servo systems. The control strategy to achieve high-precision motion is summarized in two main points: an adaptive-fuzzy friction compensator is adopted in the independent control loop of each axis to compensate the nonlinear friction, and then a method which combines global sliding mode control with two adjacent axes cross-coupling technology is proposed to minimize not only single-axis position error but also synchronous errors of all motion axes. At first, the adaptive fuzzy algorithm including dynamic model of the system is utilized to design a friction compensation controller. Next, to improve robustness of the multi-axis motion system against variation of motor parameters and external disturbances, global sliding mode control is introduced. In addition, the multi-axis synchronous control based on cross-coupling technology is elaborately designed via proportional-differential control law. The performance of the proposed control system is investigated through extensive simulations based on a popular motion platform. Furthermore, experimental study shows that the results successfully demonstrate the effectiveness of the proposed position synchronous control method for a general four-axis servo system.

Decreased autophagy is accompanied by the development of a myeloproliferative state or acute myeloid leukemia (AML). AML cells are often sensitive to autophagy‑inducing stimuli, prompting the idea that targeting autophagy can be useful in AML cytotoxic therapy. AML NB4 cells overexpressing microtubule-associated protein 1 light chain 3-green fluorescent protein were screened with 69 inhibitors to analyze autophagy activity. AML cells were treated with the polo-like kinase 1 (PLK1) inhibitors RO3280 and BI2536 before autophagy analysis. Cleaved LC3 (LC3-II) and the phosphorylation of mammalian target of rapamycin (mTOR), adenosine monophosphate-activated protein kinase, and Unc-51-like kinase 1 during autophagy was detected with western blotting. Autophagosomes were detected using transmission electron microscopy. Several inhibitors had promising autophagy inducer effects: BI2536, MLN0905, SK1-I, SBE13 HCL and RO3280. Moreover, these inhibitors all targeted PLK1. Autophagy activity was increased in the NB4 cells treated with RO3280 and BI2536. Inhibition of PLK1 expression in NB4, K562 and HL-60 leukemia cells with RNA interference increased LC3-II and autophagy activity. The phosphorylation of mTOR was reduced significantly in NB4 cells treated with RO3280 and BI2536, and was also reduced significantly when PLK1 expression was downregulated in the NB4, K562 and HL-60 cells. We demonstrate that PLK1 inhibition induces AML cell autophagy and that it results in mTOR dephosphorylation. These results may provide new insights into the molecular mechanism of PLK1 in regulating autophagy.

A feasible approach to produce xylooligosaccharides (XOS) using organic acids as catalysts by microwave-induced hydrolysis of different hemicelluloses was developed. The effects of different acids (oxalic acid, maleic acid, citric acid and sulfuric acid), acid concentration, reaction temperature and reaction time on the hemicelluloses hydrolysis were investigated. Results demonstrated that organic acid was more beneficial to the XOS production than the conventional sulfuric acid. Higher acid concentration, higher reaction temperature and longer reaction time accelerated the further depolymerization of XOS to form monosaccharide. Response surface methodology was employed to optimize the reaction conditions (temperature and time) for the production of XOS from beechwood xylan (BX), corncob hemicelluloses (CH) and recovered hemicelluloses from the industrial waste liquor of dissolving pulp (RH), respectively. The predicted highest XOS yields were achieved to 39.31% (126.54°C-7.95min), 27.29% (120.00°C-0min), 30.32% (122.63°C-15.85min), respectively, being close to the experimental value (39.42%, 27.46% and 30.89%) from BX, CH and RH, indicating the fitted models of XOS yield were in good agreement with the experimental results.

A mixed ball milling of corncob and the solid acid catalyst (SO 4 2− /SiO 2 -Al 2 O 3 /La 3+ ) followed by the ultrasonic pretreatment has been developed for the selectively catalytic hydrothermal conversion of corncob into furfural. Results showed that the combined mixed ball milling and ultrasonic pretreatment (MU) was an efficient mechanocatalytical approach to destroy the complex structure of corncob, and most of the hemicelluloses could be released from the corncob cell wall during the subsequent hydrothermal reaction. In comparison with the ultrasonic pretreatment, ball milling played a more important role in the deconstruction of corncob and the depolymerization of polysaccharides. The existence of the solid acid catalysts (SO 4 2− /SiO 2 -Al 2 O 3 /La 3+ ) during the ball milling and ultrasonic pretreatments had the significant influences on the successful conversion of corncob into furfural due to the solid–solid reaction of the solid acids and the dewaxed corncob during the pretreatment process, which was in favor of the furfural production. A highest furfural yield of 197.76 mg/g could be obtained at 190 °C for 30 min from the MU-pretreated corncob.

Natural active compounds with antioxidant properties and other potential health benefits, like quercetin (Qu), have aroused wide concern for developing bio-functional products. However, their applications are hindered by their intrinsic poor water solubility and chemical instability. In this paper, a natural antioxidant alpha lipoic acid (ALA) was grafted onto chitosan (CS) to synthesize a novel graft polymer (CS-graft-ALA). In particular, this graft-polymer could self-assemble into spherical nanomicelles in water, with a low critical micelle concentration (CMC) of 0.0076 mg/mL. As a robust and active nanocarrier, the CS-graft-ALA micelles showed high efficiency in encapsulating Qu and dispersing Qu in water. As found, the antioxidant activity of Qu was effectively enhanced when entrapped within CS-graft-ALA micelles. Moreover, CS-graft-ALA micelles could significantly improve the photo-stability and temperature-stability of Qu. The Qu/CS-graft-ALA micelles with excellent water dispersability, stability and improved antioxidant activity hold a great potential for wide applications.

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively&mdash, all above 80%.

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively—all above 80%.

Pore-forming agents have a significant influence on the pore structure of hydrogels. In this study, a porogenic technique was employed to investigate the preparation of macroporous hydrogels which were synthesized by radical copolymerization of carboxymethyl xylan with acrylamide and N-isopropylacrylamide under the function of a cross-linking agent. Six kinds of pore-forming agents were used: polyvinylpyrrolidone K30, polyethylene glycol 2000, carbamide, NaCl, CaCO3, and NaHCO3. The application of these hydrogels is also discussed. The results show that pore-forming agents had an important impact on the pore structure of the hydrogels and consequently affected properties of the hydrogels such as swelling ratio and mechanical strength, while little effect was noted on the thermal property of the hydrogels. 5-Fluorouracil was used as a model drug to study the drug release of the as-prepared hydrogels, and it was found that the drug release was substantially improved after using the NaHCO3 pore-forming agent: a cumulative release rate of up to 71.05% was achieved.

Although polysaccharide-based carbon quantum dots (CQDs) are widely used in the field of detection, most of the CQDs-based sensors only take advantage of their optical properties. In this work, considering the selectivity to target substance and reducibility of xylan-based CQDs, a high-sensitive sensor based on greenly synthesized CQDs-based nanocomposite was fabricated for dopamine (DA) detection. First, the CQDs prepared from xylan were used as the reductant and stabilizer to quickly synthesize silver nanoparticles (Ag NPs) and reduced graphene oxide (rGO), and then Ag@CQDs-rGO nanocomposite was obtained and loaded on glassy carbon electrode (GCE) to fabricate electrochemical sensor. The electrochemical sensing of DA is of great significance for studying and treating neurochemical diseases due to its potential feasibility in diagnostics. Under optimal conditions, the linear range for monitoring DA was from 0.1 to 300 μM with a limit of detection of 1.59 nM (S/N = 3). Finally, this sensor was successfully applied to detect DA in dopamine hydrochloride injection and bovine serum solution samples. The proposed strategy may broaden the application of polysaccharide-based CQDs and this sensor may provide a discriminative and sensitive analytical platform for DA clinical diagnostics and drug screening.

UDP-xylose (UDP-Xyl) is the Xyl donor used in the synthesis of major plant cell-wall polysaccharides such as xylan (as a backbone-chain monosaccharide) and xyloglucan (as a branching monosaccharide). The biosynthesis of UDP-Xyl from UDP-glucuronic acid (UDP-GlcA) is irreversibly catalyzed by UDP-glucuronic acid decarboxylase (UXS). Until now, little has been known about the physiological roles of UXS in plants. Here, we report that AtUXS1, AtUXS2, and AtUXS4 are located in the Golgi apparatus whereas AtUXS3, AtUXS5, and AtUXS6 are located in the cytosol. Although all six single AtUXS T-DNA mutants and the uxs1 usx2 uxs4 triple mutant show no obvious phenotype, the uxs3 uxs5 uxs6 triple mutant has an irregular xylem phenotype. Monosaccharide analysis showed that Xyl levels decreased in uxs3 uxs5 uxs6 and linkage analysis confirmed that the xylan content in uxs3 xus5 uxs6 declined, indicating that UDP-Xyl from cytosol AtUXS participates in xylan synthesis. Gel-permeation chromatography showed that the molecular weight of non-cellulosic polysaccharides in the triple mutants, mainly composed of xylans, is lower than that in the wild type, suggesting an effect on the elongation of the xylan backbone. Upon saccharification treatment stems of the uxs3 uxs5 uxs6 triple mutants released monosaccharides with a higher efficiency than those of the wild type. Taken together, our results indicate that the cytosol UXS plays a more important role than the Golgi-localized UXS in xylan biosynthesis.

The per-O-acylation of xylan-type hemicellulose was firstly carried out in dimethylsulfoxide/N-methylimidazole (DMSO/NMI) at room temperature without additional catalyst. The optimum conditions for esterification of xylan was investigated in terms of the molar ratio of reagents to anhydroxylose units (AXU) in xylan and the kinds of esterification reagents to obtain a high degree of substitution (DS, 1.98) and weight percent gain (WPG, 86.88 %) of xylan esters. In this solvent system, NMI acted as a solvent, a base and an excellent catalyst, therefore, the per-O-acylation of xylan (DS of 1.98) was readily accomplished in DMSO/NMI system at room temperature. Structure elucidation of xylan esters was characterized by FT-IR and NMR (1H-NMR, 13C-NMR and HSQC). FT-IR and NMR analyses provided the direct evidence of per-O-acylation of xylan under the given conditions. Furthermore, HSQC revealed the higher reactivity of hydroxyls at C-2 position than those at C-3 position of xylan. The solubility of xylan in DMSO, DMF and CHCl3 improved after esterification. TGA/DTG indicated that the thermal stability of xylan increased after the esterification with anhydrides, while decreased with acyl chlorides, probably due to degradation and hydrolysis of the acylated xylan at the presence of by-product hydrochloric acid.

The hydrothermal treatment of pentose-rich corncob under microwave irradiation was performed using SnCl4 as catalyst for furfural production in this study. The influences of the catalyst amount, reaction temperature and reaction time on the compositions of the hydrolysate and solid residue were discussed comparatively. The solid residue obtained was characterized by FTIR, XRD and SEM. The results showed that the cell wall structure of the treated corncob was destroyed to a certain extent under the function of catalysts during the treatment, and most of the hemicelluloses were released from the cell wall and entered the hydrolysate as hemicellulose-derived sugars, followed by the selective dehydration to furfural. When the temperature reached the preset value of 190 °C under microwave irradiation, the highest furfural yield of 9.0 wt% (based on the dry weight of corncob) was achieved from the one-step conversion of corncob under the microwave-assisted hydrothermal treatment with a 1 % amount of SnCl4 (based on the dry weight of corncob) and a solid-to-liquor ratio of 1:20.

A feasible approach for the production of xylose and xylooligomer from corncob was developed using oxalic acid-assisted ball milling, followed by the microwave-induced hydrothermal treatment. Parameters such as milling time, the amount of oxalic acid, hydrothermal treatment time and temperature were evaluated. Results showed that most of hemicelluloses in the cell wall could be released and degraded into xylose and xylooligomer after ball milling for 60 min in the presence of trace oxalic acid and then treated by the hydrothermal treatment under microwave. The maximum yield of xylo-sugars (xylose and xylooligomer) was 86.10% under the ball milling pretreatment of corncob for 60 min with 15-mM oxalic acid and followed by the hydrothermal treatment at 130 °C for 30 min. Under this optimal treatment condition given, the production of by-products such as acetic acid and furfural was limited.

In the present study, a graded ethanol precipitation technique was employed to obtain hemicelluloses from the alkali-extracted corncob liquid. The relationship between the structural characteristics of alkali-soluble corncob hemicelluloses and the production of furfural was investigated by a heterogeneous process in a biphasic system. Results showed that alkali-soluble corncob hemicelluloses mainly consisted of glucuronoarabinoxylans and L-arabino-(4-O-methylglucurono)-D-xylans, and the drying way had less influence on the sugar composition, molecular weights and the functional groups of hemicelluloses obtained by the different ethanol concentration precipitation except for the thermal property, the amorphous structure and the ability for the furfural production. Furthermore, alkali-soluble corncob hemicelluloses with higher xylose content, lower branch degree, higher polydispersity and crystallinity contributed to the furfural production. A highest furfural yield of 45.41% with the xylose conversion efficiency of 99.06% and the furfural selectivity of 45.84% was obtained from the oven-dried hemicelluloses precipitated at the 30% (v/v) ethanol concentration.

Herein, a novel, facile, and versatile approach to fabricate highly flexible and conductive paper is proposed by electroless deposition (ELD) with the assistance of aminocellulose as the interface layer. The obtained Cu nanoparticles (NPs)-coated cellulose paper is highly conductive with a significant low resistance of 0.38 Ω sq-1 after only 10 min of ELD treatment. This conductive cellulose paper shows excellent stability when it suffers from bending, folding, and tape adhesion cycles. With the same method, the Cu NPs can also be successfully deposited on the polypropylene (PP)-filled hybrid paper. The conductive paper exhibits very smooth and hydrophobic surface with high reflection, which can be used for special electronic devices. In a word, the fabrication of aminocellulose interface permits a controlled ELD of metal nanoparticles on paper substrate, and this mild and low-cost method opens up new opportunities for large-scale production of flexible and wearable electronics.

High strength and self-healing properties of hydrogels are of great interest in tissue engineering and biomedical fields. In this paper, nanocomposite hydrogels were prepared by freeze-thaw cycle method via fabricating physical cross-links into chemical-crosslinked formed polymer network. The properties of nanocomposite hydrogels were characterized by FTIR, XRD, SEM, rheological analysis, swelling analysis and mechanical test. The results showed that the electrostatic interaction between CNC and QAX and the high amount of PVA (20 wt%) were favorable to improve the mechanical properties of nanocomposite hydrogels, in which the maximum compressive strength and elongation at break of nanocomposite hydrogels were 1.56 MPa and 771 %, respectively. Prepared hydrogels achieved self-healing without any external stimuli at room temperature with the help of hydrogen bonds and the entanglement of long polymer chains, the healing efficiency was 37.03 % within 48 h. These hydrogels with high strength and self-healing properties will offer new insights for xylan application.

The viable bacterial strains in conventional yogurt are intolerant to bile acid, which consequently cannot survive the conditions and their beneficial bioactivities are thus lost. We have previously shown that Lactobacillus casei Q14 ( Lac-Q14), a probiotic, has the potential to alleviate diabetes in rats. Herein, we used Lac-Q14 as the starter culture to ferment yogurt and explore the mechanisms of the bioactivity in diabetic rats. The results showed that Lac-Q14 yogurt improved blood glucose and insulin level, lowered gene expression of critical enzymes involved in liver gluconeogenesis. Pyrosequencing showed an obvious change in the composition of intestinal microbiota in Lac-Q14 yogurt treated rats. The abundance of 21 genera differed significantly between the Lac-Q14 yogurt group and diabetes group. Quite a few short-chain fatty acid (SCFA)-producing bacteria were selectively enriched, along with increased concentrations of SCFA and downstream Glucagon-like peptide-1 (GLP-1) and Peptide YY (PYY) secretion.

High strength hydrogels open new possibilities in the fields of bioengineering and biomedical. In this paper, a highly efficient one-pot strategy was developed to prepare carboxymethyl xylan-g-poly (acrylic acid) (CMX-g-PAA) hydrogels with high compression strength, high elongation and high elasticity by using the metal coordination and the reinforcement of hydroxylate multi-walled carbon nanotubes (HCNTs). Prepared hydrogels were characterized by means of FTIR, XRD, SEM, rheological measurements as well as their swelling and mechanical properties. Results showed that the Fe3+-carboxyl coordination and HCNTs imparted hydrogels with high strength and good rapid recovery properties, in which the maximum high compressive strength and elongation at break were achieved to 10.4 MPa and 1032%, and the shape of hydrogels almost returned to the original shape after the external force was removed after 30 cycles of compression. These hydrogels also exhibited Fe3+-triggered shape memory properties. Therefore, as-prepared hydrogels possessing high strength, rapid recovery and shape memory properties, could broaden access for application in intelligent toys, electronic skin, biosensing, and tissue engineering.

Background:: Biosensors are widely applied for the detection of bio-molecules in blood glucose , cholesterol, and gene. Cellulose as the most dominating natural polymer has attracted more and more interest, especially in the field of medicine such as advanced medical diagnosis. Cellulose could endow biosensors with improved biocompatibility, biodegradability and nontoxicity, which could help in medical diagnosis. This mini-review summarizes the current development of cellulose-based biosensors as well as their applications in medical diagnosis in recent years. Methods: After reviewing recent years’ publications we can say that, there are several kinds of cellulose used in biosensors including different cellulose derivatives, bacterial cellulose and nanocellulose. Different types of cellulose-based biosensors, such as membrane, nano-cellulose and others were briefly described in addition to the detection principle. Cellulose-based biosensors were summarized as in the previous papers. The description of various methods used for preparing cellulose-based biosensors was also provided. Results: Cellulose and its derivatives with their unique chemical structure proved to be versatile materials providing a good platform for achieving immobilizing bioactive molecules in biosensors. These cellulose-based biosensors possess various desirable properties such as accuracy, sensitivity, convenience, low cost and fast response. Among them, cellulose paper-based biosensors have the advantages of low cost and easy operation. Nano-cellulose has unique properties such as a large aspect ratio, good dispersing ability and high absorption capacity. Conclusion: Cellulose displays a promising application in biosensors which could be used to detect different bio-molecules such as glucose, lactate, urea, gene, cell, amino acid, cholesterol, protein and hydroquinone. In future, the attention will be focused on designing miniaturized, multifunctional, intelligent and integrated biosensors. Creation of low cost and environmentally friendly biosensors is also very important.

A sensitive and reversible sensing platform based on fluorescent carbon dots (CDs) allowing capture and detection of metal ions is of significance for developing diagnostic probes and in-situ environmental-monitoring. Here, a simple and effective method for converting biomass lignin into fluorescent CDs is developed. The obtained CDs, with stable fluorescence and excellent water solubility, are fabricated as unique model biosensors to access the metal-induced quenching mechanism. It is demonstrated that selective fluorescence quenching behaviors of lignin CDs are firstly found related to the valence-state of metal ions. Moreover, a reversible control of CDs fluorescence is realized by introducing reducing agents. This novel biosensor and the approach to quenching mechanism may evoke new insight in designing ions-sensor and monitoring biologic redox signal.

Introducing multifunctional groups and inorganic material imparts xylan-based hydrogels with excellent properties, such as responsiveness to pH, temperature, light, and external magnetic field. In this work, a composite hydrogel was synthesized by introducing acid treated carbon nanotubes (AT-CNTs) into the maleic anhydride modified xylan grafted with poly(N-isopropylacrylamide) (MAX-g-PNIPAM) hydrogels network. It was found that the addition of AT-CNTs affected the MAX-g-PNIPAM hydrogel structure, the swelling ratio and mechanical properties, and imparted the hydrogel with new properties of electrical conductivity and near infrared region (NIR) photothermal conversion. AT-CNTs could reinforce the mechanical properties of MAX-g-PNIPAM hydrogels, being up to 83 kPa for the compressive strength when the amount was 11 wt %, which was eight times than that of PNIPAM hydrogel and four times than that of MAX-g-PNIPAM hydrogel. The electroconductibility was enhanced by the increase of AT-CNTs amounts. Meanwhile, the composite hydrogel also exhibited multiple shape memory and NIR photothermal conversion properties, and water temperature was increased from 26 °C to 56 °C within 8 min under the NIR irradiation. Thus, the AT-CNTs reinforced MAX-g-PNIPAM hydrogel possessed promising multifunctional properties, which offered many potential applications in the fields of biosensors, thermal-arrest technology, and drug-controlled release.

The hydrogels obtained from renewable resources have aroused great interests because they are nontoxic, economical, biodegradable, and biocompatible. Hemicellulose is the second most abundant polysaccharides after cellulose in lignocellulosic biomass. In recent years, hemicellulose-based hydrogels as biomaterials have received ever-increasing attention and they have a wide range of the promising applications in drug delivery and release, waste treatment, dye adsorption, and tissue engineering because of their peculiar physicochemical properties. This paper described the structure of hemicellulose in plant and its physical-chemical prosperities, and summarized the type of hemicellulose-based hydrogels and their potential application, which provide useful information for the utilization of hemicellulose polymers.

A new xylan ester (xylan 3,5-dinitrobenzoate) as a creatinine adsorbent was prepared by the homogeneous acylation of xylan with 3,5-dinitrobenzoyl chloride in 1-butul-3-methylimidazolium chloride ionic liquid. The influences of reaction conditions on the degree of substitution values of xylan esters were discussed. Results indicated that xylan esters with the degree of substitution range from 1.34 to 1.77 were obtained under the given conditions. The FTIR and 13 C NMR spectroscopies provided the evidence of grafting 3,5-dinitrobenzoyl groups onto the backbone of xylan. Moreover, the adsorption properties of the xylan ester for creatinine were also investigated. Isotherm studies showed that the sorption capacities for creatinine were 2.45, 2.08 and 1.86 mg/g for 23, 30 and 37 °C, respectively. Thermodynamic studies performed indicated the sorption process mainly was controlled by the chemical adsorption. Therefore, xylan 3,5-dinitrobenzoate displayed the promising application in the treatment of chronic renal failure by the creatinine adsorption as the new oral adsorbent.

Given that the glycerol organosolv pretreatment (GOP) can effectively improve the hydrolyzability of various lignocellulosic substrates, physicochemical changes of the substrate before and after the pretreatment was characterized to elucidate what is responsible for it. The effect of GOP on the main components and hydrolyzability of wheat straw was revisited. Results demonstrate that the GOP should be a promising candidate for the current pretreatment. Then the composition and structure of substrates was measured at multi-dimensional scales by using various analytic equipment such as TGA, SEM, AFM, CLSM, FT-IR, XRD and solid-state CP/MAS (13)C NMR. This paper reports some new insights on the mechanism behind that, which can be beneficial for further development, optimization, and scale-up of the GOP process.

Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl 4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H 2 O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl 4 as catalysts under the optimized reaction conditions (150 °C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization.

The self-healing capability of hydrogels has become a hot topic in the area of hydrogel research. An economical, convenient, eco-friendly, and reproducible approach for the preparation of self-healing xylose-based hydrogels is introduced in this article. First, methylguanidine hydrochloride was grafted onto the backbone of xylose using ethylene glycol as a crosslinking agent, then xylose with guanidinium ion pendants on its peripheries was entangled with exfoliated layered anionic montmorillonite (MMT) clay nanoplatelets under the dispersion of sodium polyacrylate (PAAS), thus forming xylose-based hydrogels, which were connected by hydrogen bonds and displayed intermolecular adsorption because of their internal spongy porous structure. The synthesized xylose-based hydrogels had a rapid self-healing ability and showed good swelling property. The structure and morphology of the composite hydrogels were characterized using FT-IR and SEM. The compression stress–strain results suggest that the elasticity of the xylose-based hydrogels increased with the increase of modified xylose solution, and the compression stress increased with the increasing concentration of modified xylose. Thermal gravimetric analysis (TGA) indicated that the composite hydrogels had a good heat resistant property due to the added inorganic MMT. All these properties demonstrate that the composite hydrogels have potential applications such as water absorbents, flame retardants, and as other functional materials.

Temperature/pH dual-responsive hydrogels were prepared by the grafting copolymerization of xylan possessing different functional groups with N-isopropylacrylamide and acrylamide using N,N′-methylenebis-acrylamide as a cross-linker and 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator via ultraviolet irradiation. The influence of xylan and glycidyl methacrylate-modified xylan (GMAX) as the raw materials on the mechanical properties of hydrogels was comparatively investigated. Hydrogels were characterized by SEM, FTIR, TGA and XRD. The prepared hydrogels demonstrated a rapid phase transition temperature around 35 °C. The cumulative release rate of acetylsalicylic acid for xylan-based hydrogels and GMAX-based hydrogels reached to 77.5% and 84.2% in the intestinal fluid, respectively. GMAX-based hydrogels had a drug encapsulation efficiency of 95.21% and low drug release rate in gastric fluid. NIH3T3 cells in GMAX-based hydrogels had the high cell viability by MTT essay. Therefore, GMAX-based hydrogels had the good biocompatibility which make them promising in biomedical applications, especially as intestinal-targeted drug carriers.

Corncob with a high content of pentose-rich hemicelluloses shows great potential for furfural production. In this paper, an environmentally-friendly two-step process for furfural production was developed by the hydrothermal pretreatment of corncob and the heterogeneous catalysis of the hydrolysate using a solid acid catalyst. The hydrothermal pretreatment was applied to release hemicelluloses from the cell wall of the corncob, which were hydrolyzed into monosaccharide and oligosaccharide under the investigated conditions (160–190 °C, 0–60 min). Subsequently, heterogeneous catalysis of the hydrolysate obtained from the hydrothermal pretreatment was performed using SO42−/SiO2–Al2O3/La3+ as a solid acid catalyst at 150 °C for 2.5 h. The maximum yield of furfural achieved was up to 21% under the investigated experimental conditions from the catalysis of hydrolysates obtained at 190 °C for 60 min in the hydrothermal process. Moreover, there was no obvious change in the catalytic activity of SO42−/SiO2–Al2O3/La3+ after four runs, and only a decline of 5.28% yield of furfural was observed. This two-step process is an environmentally-friendly process for furfural production from pentose-rich biomass and serves as an effective approach for recovering the solid catalyst from the reaction medium.

Using tree-ring data from the northernmost marginal area of the East Asian summer monsoon (EASM) in North China, May–July mean Palmer drought severity index (PDSI) was reconstructed back to 1767 AD. The reconstruction captured 52.8% of the variance over the calibration period from 1945 to 2005 AD and showed pronounced pluvial periods during 1850–1905, 1803–1811 and 1940–1961 and dry periods during 1814–1844, 1916–1932 and 1984–2012. These anomalous periods have previously been reported in other parts of North China. Spatial correlation analyses and comparisons with other hydroclimatic indices in North China indicated that our new PDSI reconstruction could represent spatial and temporal drought variability in this region well. Our work also suggested that the drying tendency currently observed in the northern part of North China (including the study area) is consistent with the weakening of the EASM. Meanwhile the drying trend was seemingly restrained at present in the southern part of North China. Spatial correlation patterns with global sea surface temperature (SST) indicated that the regional hydroclimatic variability in North China was tightly linked to SST over the joining area of Asia and Indian–Pacific Ocean (AIPO), especially over the tropical western Pacific. When SST from prior November to current July (NJ-SST) in the AIPO area was anomalously high (low), the thermal contrast between Asian land and ocean was weakened (strengthened), and the EASM was correspondingly weakened (strengthened), thereby causing droughts (pluvials) in North China. The results of this study do not only provide useful information for assessing the long-term climate change in North China, but also suggest that abnormal variability in NJ-SST over the AIPO area could be used to forecast hydroclimatic conditions in North China.

The effects of chemical pretreatments (dilute H2SO4, dilute NaOH, and NH4OH) and biological pretreatments (Coriolus versicolor and Daedalea quercina) on the enzymatic hydrolysis of Eucalyptus were investigated. The results showed that Eucalyptus obtained from different regions possess similar chemical compositions and that the optimum particle sizes for reducing sugar production were 60- to 80-mesh. Contrary to the negative influences of a dilute H2SO4 pretreatment, an alkali pretreatment showed positive effects on Eucalyptus saccharification. This phenomenon may had been attributed to the efficient removal of lignin and the stronger structural damage during the alkali pretreatment process. In comparison with the chemical pretreatments, a higher reducing sugar yield could be achieved from the biological pretreated Eucalyptus. The highest reducing sugar yield of 97.14 mg/g was obtained from the Guangxi (GX) Eucalyptus that was pretreated with Daedalea quercina.

Ring-opening graft polymerization (ROGP) of l-Lactide (l-LA) is a practical method of altering the physical and chemical properties of lignocellulose. Previous studies have mainly investigated cellulose and tin-based catalysts, particularly of tin(II) 2-ethylhexanoate (Sn(oct)2), at high temperatures and reported low graft efficiencies. In the present study, ROGP of l-LA was successfully achieved on xylan-type hemicelluloses in ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl) using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an effective organic catalyst. Mild reaction condition (50 °C) was used to limit transesterification, and thus enhance the graft efficiency. The hydroxyl groups on xylan acted as initiators in the polymerization, and DBU, enhanced the nucleophilicity of the initiator and the propagating chain. Xylan-graft-poly(l-Lactide) (xylan-g-PLA) copolymer with a degree of substitution (DS) of 0.58 and a degree of polymerization (DP) of 5.51 was obtained. In addition, the structures of the xylan-g-PLA copolymers were characterized by GPC, FT-IR and NMR, confirming the success of the ROGP reaction. Thermal analysis revealed that the copolymers exhibited a single glass-transition temperature (Tg), which decreased with increasing molar substitution (MS). Thus, modification resulted in the graft copolymers with thermoplastic behavior and tunable Tg.

Background Overexpression of cyclin D1 dependent kinases 4 and 6 (CDK4/6) is a common feature of many human cancers including leukemia. LEE011 is a novel inhibitor of both CDK4 and 6. To date, the molecular function of LEE011 in leukemia remains unclear. Methods Leukemia cell growth and apoptosis following LEE011 treatment was assessed through CCK-8 and annexin V/propidium iodide staining assays. Cell senescence was assessed by β-galactosidase staining and p16INK4a expression analysis. Gene expression profiles of LEE011 treated HL-60 cells were investigated using an Arraystar Human LncRNA array. Gene ontology and KEGG pathway analysis were then used to analyze the differentially expressed genes from the cluster analysis. Results Our studies demonstrated that LEE011 inhibited proliferation of leukemia cells and could induce apoptosis. Hoechst 33,342 staining analysis showed DNA fragmentation and distortion of nuclear structures following LEE011 treatment. Cell cycle analysis showed LEE011 significantly induced cell cycle G1 arrest in seven of eight acute leukemia cells lines, the exception being THP-1 cells. β-Galactosidase staining analysis and p16INK4a expression analysis showed that LEE011 treatment can induce cell senescence of leukemia cells. LncRNA microarray analysis showed 2083 differentially expressed mRNAs and 3224 differentially expressed lncRNAs in LEE011-treated HL-60 cells compared with controls. Molecular function analysis showed that LEE011 induced senescence in leukemia cells partially through downregulation of the transcriptional expression of MYBL2. Conclusions We demonstrate for the first time that LEE011 treatment results in inhibition of cell proliferation and induction of G1 arrest and cellular senescence in leukemia cells. LncRNA microarray analysis showed differentially expressed mRNAs and lncRNAs in LEE011-treated HL-60 cells and we demonstrated that LEE011 induces cellular senescence partially through downregulation of the expression of MYBL2. These results may open new lines of investigation regarding the molecular mechanism of LEE011 induced cellular senescence. Electronic supplementary material The online version of this article (doi:10.1186/s12935-017-0405-y) contains supplementary material, which is available to authorized users.

Among the natural macromolecules potentially used as the scaffold material in hydrogels, xylan has aroused great interest in many fields because of its biocompatibility, low toxicity, and biodegradability. In this work, new pH and thermoresponsive hydrogels were prepared by the cross-linking polymerization of maleic anhydride-modified xylan (MAHX) with N-isopropylacrylamide (NIPAm) and acrylic acid (AA) under UV irradiation to form MAHX-g-P(NIPAm-co-AA) hydrogels. The pore volume, the mechanical properties, and the release rate for drugs of hydrogels could be controlled by the degree of substitution of MAHX. These hydrogels were characterized by swelling ability, lower critical solution temperature (LCST), Fourier-transform infrared (FTIR), and SEM. Furthermore, the cumulative release rate was investigated for acetylsalicylic acid and theophylline, as well as the cytocompatibility MAHX-based hydrogels. Results showed that MAHX-based hydrogels exhibited excellent swelling–deswelling properties, uniform porous structure, and the temperature/pH dual sensitivity. In vitro, the cumulative release rate of acetylsalicylic acid for MAHX-based hydrogels was higher than that for theophylline, and in the gastrointestinal sustained drug release study, the acetylsalicylic acid release rate was extremely slow during the initial 3 h in the gastric fluid (24.26%), and then the cumulative release rate reached to 90.5% after sustained release for 5 h in simulated intestinal fluid. The cytotoxicity experiment demonstrated that MAHX-based hydrogels could promote cell proliferation and had satisfactory biocompatibility with NIH3T3 cells. These results indicated that MAHX-based hydrogels, as new drug carriers, had favorable behavior for intestinal-targeted drug delivery.

An efficient homogeneous catalytic process was developed for the dehydration of xylose to furfural using inorganic salts as catalysts in a water/dimethyl sulfoxide (DMSO) system under mild condition. The effects of the types of inorganic salts were compared. The results showed that chlorides had higher catalytic performance than other salts, and SnCl4 was the most effective chloride. The catalytic activity of paired SnCl4/LiCl catalysts was much higher than that of the single salt, and when the distribution coefficient (χSnCl4) was 0.8, the maximum furfural yield was 56.9%. The effects of the reaction conditions on the furfural yield were also investigated. The highest furfural yield, 63.0%, was achieved at 130 °C for 6 h under the optimized reaction conditions.

Hemicelluloses were extracted from holocellulose of bamboo by alkaline treatment. The phosphorylated poly(vinyl alcohol) (P-PVA) samples with various substitution degrees were prepared through the esterification of PVA and phosphoric acid. A series of hydrogels of semi-interpenetrating polymeric networks (semi-IPN) composed of hemicelluloses-g-poly(acrylic acid) (HM-g-PAA) and the phosphorylated poly(vinyl alcohol) (P-PVA) were prepared by radical polymerization using potassium persulphate (KPS) as initiator. The HM-g-PAA networks were crosslinked by N,N-methylenebisacrylamide (MBA) as a crosslinking agent in the presence of linear P-PVA. FT-IR results confirmed that the hydrogels comprised a porous crosslink structure of P-PVA and HM with side chains that carried carboxylate and phosphorylate groups. SEM observations indicated that the incorporation of P-PVA induced highly porous structure, and P-PVA was uniformly dispersed in the polymeric network. The interior network structures of the semi-IPN matrix became more porous with increasing P-PVA. The TGA results showed that the thermo-decomposing temperature and thermal stability were increased effectively for intruding the chain of P-PVA. The maximum equilibrium swelling ratio of hydrogels in distilled water and 0.9 wt% sodium chloride solutions was up to 1085 g g(-1) and 87 g g(-1), respectively. The compressive strength increased with increasing the MBA/HM and P-PVA/HM ratios, and decreased with the increment of AA/HM ratio.

Selectively catalytic hydrothermal pretreatment of corncob into xylose and furfural has been developed in this work using solid acid catalyst ( SO 4 2 - /TiO2–ZrO2/La3+). The effects of corncob-to-water ratio, reaction temperature and residence time on the performance of catalytic hydrothermal pretreatment were investigated. Results showed that the solid residues contained mainly lignin and cellulose, which was indicative of the efficient removal of hemicelluloses from corncob by hydrothermal method. The prepared catalyst with high thermal stability and strong acid sites originated from the acid functional groups was confirmed to contribute to the hydrolysis of polysaccharides into monosaccharides followed by dehydration into furfural. Highest furfural yield (6.18 g/100 g) could be obtained at 180 °C for 120 min with 6.80 g/100 g xylose yield when the corncob/water ratio of was 10:100. Therefore, selectively catalytic hydrothermal pretreatment of lignocellulosic biomass into important platform chemicals by solid acids is considered to be a potential treatment for biodiesel and chemical production.

Recently, more and more attention has been centered on developing cheaper, highly efficient, environmentally friendly adsorbents for the removal of metal ions from industrial effluents. The present work deals with the removal of metal ions from an aqueous solution using a highly efficient, biodegradable adsorbent from hydrogel prepared by the free radical graft polymerization of sugarcane bagasse with acrylic acid and acrylamide using N, N-methylene-bis-acrylamide as a crosslinker. FTIR and SEM/EDX spectroscopies were used to characterize the structure and the morphology of adsorbent before and after the metal ions adsorption. The effects of pH, contact time, and initial concentration of metal ion on the adsorption capacity were studied. The adsorption equilibrium time of Pb2+, Cd2+, and Cu2+ were 60, 90, and 180 min, respectively. The maximum adsorption capacities of Cu2+, Pb2+, and Cd2+ were 268, 700, and 320 mg/g, respectively. The adsorption data were fit to often-used models for adsorption kinetics and isotherms. It was determined that the experimental results were well fitted to the pseudo-second-order equation and Langmuir adsorption isotherms.