Abstract  Various lactic acid bacteria were blended into freshly-made starter-free Cheddar-type cheese (acidified with glucono-delta-lactone) to form slurries that were ripened anaerobically at 32 degrees C for five days. Reversed-phase HPLC analysis of the water-soluble nitrogen extracts from the slurries (secondary proteolysis) showed differences in the numbers and areas of peptide peaks, suggesting differences in proteolytic abilities among species and strains of lactic acid bacteria. Tertiary proteolysis, assessed by spectrophotometric measurements of Cd-ninhydrin colour yields of the water-soluble nitrogen extracts also showed differences in the concentrations of free amino acids produced by the different lactic acid bacteria. Results suggest that casein proteolysis by starter and non-starter bacteria during cheese ripening may be specific for various species and strains of lactic acid bacteria.

Abstract  Reactions to human serum albumin (HSA) in therapeutic plasma exchange (TPE) are rare. Nevertheless, older literature describes possible adverse effects, including specific immune responses to albumin or other proteins, and reactions due to contaminating organisms or pyrogen. During an eight day period three patients in our unit had unusual reactions after infusion of 1.5-2 L of HSA. Patient 1 had trembling that persisted for 20 min. Patient 2 had shaking for 40 min despite calcium gluconate infusion, and fever to 100.8 degrees F. Patient 3 had severe rigors that subsided after 90 min when meperidine was finally given, and fever to 103.5 degrees F. Record reviews revealed that all three patients had received HSA from the same lot, and that only one other TPE patient had received HSA from that lot. Neither our pharmacy nor the manufacturer was aware of other reactions associated with that lot. Material from a bottle only partially infused to patient 3 was negative in culture and was negative far pyrogen when retested by the manufacturer. Nevertheless, because patients 1 and 2 had each had multiple previous uneventful TPEs and because all three patients tolerated subsequent TPEs without incident when another brand of HSA was used, we conclude that these patients had pyrogen reactions to the implicated HSA lot. This experience illustrates the value of cluster recognition in arousing suspicion of unusual reactions to HSA and the value of recorded lot numbers in pursuing such suspicions. Apheresis personnel should be aware of the potential for pyrogen reactions with HSA and should record lot numbers of all fluids infused during TPE. (C) 1995 Wiley-Liss, Inc.

Abstract  Most Americans do not meet the adequate intake (AI) for calcium; calcium supplements can help meet requirements. Calcium supplementation has been found to be beneficial for bone health in children, young adults, and menopausal women. In addition to calcium, vitamin D is necessary for bone health and is generally deficient in the industrialized world. Calcium from carbonate and citrate are the most common forms of calcium supplements. Calcium carbonate, the most cost-effective form, should be taken with a meal to ensure optimal absorption. Calcium citrate can be taken without food and is the supplement of choice for individuals with achlorhydria or who are taking histamine-2 blockers or protein-pump inhibitors. Calcium lactate and calcium gluconate are less concentrated forms of calcium and are not practical oral supplements. Research on hydroxyapatite as a source of calcium is limited, so this form of calcium is not recommended. The maximum dose of elemental calcium that should be taken at a time is 500 mg. U.S. Pharmacopeia-verified calcium supplements meet vigorous manufacturing and quality requirements. Absorption from calcium-fortified beverages varies and in general is not equal to that of milk. Potential adverse effects of calcium supplementation include gastrointestinal complaints. Renal calculi in most studies have not been associated with calcium supplementation. The risk of advanced and fatal prostate cancer has been associated with calcium intakes from food or supplements in amounts >1500 mg/d.

Abstract  The oxidation of 2-acetamido-2-deoxy-D-glucose by Cr-VI in perchloric acid has been found to follow the rate law: -d[Cr-VI]dt = (a+b[H+](2)+c[GlcNAc](2)[H+](2)) [Cr-VI](T) where a = 7.37 +/- 0.35 x 10(-5) s(-1); b = 3.90 +/- 0.67 x 10(-4) M(-2) s(-1); and c = 1.18 +/- 0.01 x 10(-3) M(-4) s(-1). This rate law corresponds to the reaction leading to the formation of 2-acetamido-2-deoxy-D-gluconic acid when a 20-fold or higher excess of aldose over chromium is employed. The results are discussed in terms of a possible mechanism with the associated reaction kinetics.

Abstract  Kinetic expressions have been developed for the initial phase of the reactions between ozone and methyl-beta-D-glucopyranoside, a model compound for cellulose, in aqueous solutions at moderately low pH (pH 3) and ambient temperature. Ozone is reasonably stable under these conditions. The reaction is first order in the glucoside and ozone, second order overall. Kinetic and analytical data suggest that the glucoside is directly attacked by ozone to form polyoxide intermediates. The alpha-glucoside was more stable and was attacked by ozone exclusively at the acetal oxygen in the initial phase of the reaction. In contrast, the beta-anomer was ozonized nearly twice as fast, and was attacked by ozone mainly at the C-H bond of the anomeric carbon. The latter reaction resulted in the formation of delta-gluconolactone, probably by way of a hydrotrioxide intermediate. The fragmentation of the intermediate could be assisted by properly oriented non-bonding orbitals of the two acetal oxygens. These stereoelectronic rules were previously proposed by Deslongchamp and coworkers on the ozonolysis of acetals in non-aqueous media. The activation energy for the reaction was 69.5 kJ/mole in both acetic and sulfuric acid solutions at pH 3. The presence of transition metal-ion, in particular Co(II) and Fe(II) ions, resulted in enhancement of both ozone decomposition and degradation of the glycoside, apparently caused by free radical reactions. In some cases, addition of acetic acid led to substantial suppression of the degradation of the glucoside.

Abstract  This work aimed at evaluating the ability of theological measurements to describe the quality of Traditional Balsamic Vinegars (TBV) with respect to their composition and sugar crystallization. With this aim, shearing experiments were conducted on 100 samples of TBV using a controlled-strain rotational rheometer, whereas the concentration of glucose, fructose, acetic acid, gluconic acid, malic acid as well as refractive index and titrable acidity were determined according to the normal procedure for quality assessment of TBV. A broad range for the rheological response was observed including Newtonian and shear-thinning behavior. A Joining Tree Cluster Analysis (JTCA) was able to classify the investigated vinegars into meaningful classes based on the stress data alone. Moreover, Principal Component Analysis (PCA) was performed to link composition data to rheological properties, and finally, Multivariate Regression Analysis (MRA) evaluated the contribution of the main constituents to vinegar viscosity. The results suggested that rheological analysis must be carried out in order to spot some fundamental aspects of the vinegar texture, which cannot be detected otherwise. In particular, two rheological parameters were proposed as objective and quantitative descriptors of TBV quality: the shear viscosity measured at 500 s(-1) accounting for the vinegar composition, and the flow behavior index accounting for sugar crystallization. (C) 2007 Elsevier Ltd. All rights reserved.

Abstract  The corrosion inhibition effect and mechanism of D-sodium gluconate for reinforcing steel in the simulated concrete pore solution containing Cl-were studied by electrochemical techniques, including corrosion potential, potentiodynamic polarization, and electrochemical impedance spectroscopy measurements. The results indicate that 0.01 M D-sodium gluconate showed a good corrosion inhibition effect on reinforcing steel in the simulated concrete pore solution containing 0.1 M NaCl because it strongly hindered the anodic reactions. The inhibition mechanism could be explained on the basis of the competitive adsorption between gluconate anions and chloride ions on the reinforcing steel surface. And D-sodium gluconate could eventually form a compact adsorptive film by strong chelation and effectively inhibit the initiation of reinforcing steel corrosion.

Abstract  Thermodynamic properties of gluconic acid (HGH(4)(aq)) complexation with Nd(III) have been studied in acidic solutions at 25 degrees C and 1.0M NaClO4 by potentiometry, spectrophotometry and calorimetry. Three Nd(III)/gluconate complexes were identified in solutions of pC(H) 2.5-4.5. The formation constants and the complexation enthalpies are: log beta(1) =2.55 +/- 0.05 and Delta H-1 degrees = -(8.22 +/- 0.23) kJ mol(-1) for Nd(GH(4))(2+), log beta(2)=4.45 +/- 0.05and Delta H-2 degrees = -(15.3 +/- 0.4) kJ mol(-1) for Nd(GH(4))(2)(+), and log beta(3) = 5.60 +/- 0.15 and Delta H-3 degrees = -(24.6 +/- 0.6) kJ mol(-1) for Nd(GH(4))(3)(aq). The thermodynamic parameters indicate that gluconic acid, like other alpha-hydroxycarboxylic acids, forms stronger complexes with Nd(III) than simple monocarboxylic acids, likely by the participation of the alpha-hydroxyl group during complexation. The same type of binding appears to occur with Ca2+ and NpO2+ as the 1:1 stability constants are linearly correlated with the effective cationic charges of the metal cations. (c) 2007 Elsevier B.V. All rights reserved.

Abstract  An integrated experimental and computational investigation reveals that surface lattice oxygen of copper oxide (CuO) nanoleaves activates the formyl C-H bond in glucose and incorporates itself into the glucose molecule to oxidize it to gluconic acid. The reduced CuO catalyst regains its structure, morphology, and activity upon reoxidation. The activity of lattice oxygen is shown to be superior to that of the chemisorbed oxygen on the metal surface and the hydrogen abstraction ability of the catalyst is correlated with the adsorption energy. Based on the present investigation, it is suggested that surface lattice oxygen is critical for the oxidation of glucose to gluconic acid, without further breaking down the glucose molecule into smaller fragments, because of C-C cleavage. Using CuO nanoleaves as catalyst, an excellent yield of gluconic acid is also obtained for the direct oxidation of cellobiose and polymeric cellulose, as biomass substrates.

Abstract  Commercial and home prepared TiO2 samples were functionalized with a commercial Keggin heteropolyacid (HPA) H3PW12O40 (PW12) or with a hydrothermally home prepared K7PW11O39 salt (PW11). All the materials were characterized by specific surface area measurements (BET), XRD analyses, Raman, DRS along with SEM observations and they have been used for glucose photocatalytic conversion in an aqueous suspension. Different reaction extents and distribution of intermediate oxidation products were observed depending on the photocatalyst. Gluconic acid, arabinose, erythrose and formic acid were observed as oxidation products when bare TiO2 or HPA/TiO2 composite materials were used. Glucose isomerization to form fructose was also observed and in some runs traces of glucaric acid and glyceraldehyde were also found. The carbon mass balance was accomplished in the presence of the commercial Evonik P25 TiO2 powder and the composites where TiO2 was present, whereas the presence of the solvothermically prepared TiO2 gave rise to a carbon unbalance, due to strong adsorption of the products on the photocatalyst surface. No reactivity was observed in the presence of PW12 alone while PW11 induced only isomerization of the glucose.

Abstract  The occurrence of metal corrosion can greatly reduce the air-conditioning efficiency, and even affect the safe and stable operation of equipment in central air-conditioning cooling water circulation system. Adding corrosion inhibitor to cooling water system is currently the most commonly and effective method. Electrochemical impedance method is used to evaluate the corrosion performance of single sodium tungstate, sodium molybdate, and sodium gluconate, while polarization curve method is used to evaluate the corrosion performance of two compound agent. Results show that corrosion performance of sodium tungstate, sodium molybdate, and sodium gluconate is ranged as follows: sodium tungstate > sodium gluconate > sodium molybdate. There has synergistic effect between sodium tungstate and sodium gluconate, as well as between sodium tungstate and sodium molybdate, and mixed use can improve corrosion effect. The optimized prescription is that, the sodium tungstate is 65 mg/L, sodium molybdate is 35 mg/L, by this way, the corrosion rate can reach 98.31%.

Abstract  The effect of casein glycomacropeptide (CMP) on the self-assembly and gelation of sodium caseinate (NaCas) was studied. Acid gelation was induced by the addition of glucono-delta-lactone to NaCas alone and to NaCas/CMP mixtures at ratios 1/1 and 3/1. The results showed that the interactions among NaCas and CMP, determined by particle size measurement, affect the self-assembly of NaCas that occurs on decreasing pH. When the decrease in pH leads to the formation of NaCas acid gels, the presence of CMP alters the pH of gelation, texture and microstructure of these gels, resulting in a protein network with smaller aggregates and higher strength. Therefore, the incorporation of CMP on NaCas solutions not only has a potential benefit related to the bioactive properties provided by CMP, but also provides a control in the textural properties of the gels obtained by acidification. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract  Introduction. Hydrofluoric acid is a fluoride-substituted compound used in the chemical industry. Burns and hypocalcaemia result from ingestion or contact with the skin or mucosal membranes. We observed burns and skin necrosis on the hands after home use of low-concentration hydrofluoric acid.

Case report. A 57-year-old woman consulted in February 1994 for oedema, erythema and very painful burns of the palms of both hands. The day before, she had used a home-made furniture cleanser containing 5 p. 100 hydrofluoric acid. At admission, cal calcium and radiography of the two hands were normal. She was given a topical application of 5 p. 100 calcium chloride. The clinical course was favourable with squamation of both palms then necrotic lesions of the pulp on the 1 st, 2 nd and 3 rd fingers. Discussion. Such exposure in a household situation is unusual. Hydrofluoric acid has two dangerous mechanisms of action. First it is a caustic substance producing late-onset burns and secondly hypocalcaemia results from precipitation of insoluble calcium fluoride. The risk of hypocalcaemia is greatest when a large aera of the skin is exposed. Prognosis depends on early treatment based on prevention of hypocalcaemia by abundant washing of the teguments and permanent application of a 5 p. 100 calcium gluconate solution associated with local skin treatments. Careful follow-up is required with regular calcium chemistries.

Abstract  2-Carboxy ethyl phosphonic acid (2-CEPA) in the presence of Zn2+ ions synergistically inhibits mild steel corrosion in 60 ppm chloride solutions. Calcium gluconate (CG) enhances inhibition. Electrochemical and weight change methods are used to study synergistic inhibition, and the mechanism of inhibition is discussed.

Abstract  1. Experiments were conducted to test for the presence of basolateral Na+ channels in the rat lingual epithelium. Researchers have proposed a model in which some lingual taste cells have Na+ channels in the basolateral membrane. That model is designed to account for the portion of the neural taste response and the portion of the transepithelial short-circuit current (I-sc) in vitro that are insensitive to mucosal amiloride; some Na+ would diffuse across the tight junction into the cell via this lateral pathway, and would be transported out of the cell by Na+ pumps in the basal membrane. The model could also account for the differential effect of mucosal amiloride on Na+ salts of various anions, in which the neural taste responses to Na+ salts with anions larger than Cl- are more sensitive to mucosal amiloride than is the taste response to NaCl.

2. Voltage-clamp data were obtained from an in vitro preparation of the anterior-dorsal rat tongue epithelium in which the connective tissue was removed by enzyme digestion. I-sc in a modified Ussing chamber was reduced by amiloride in the submucosal solution.

3. The pattern of sensitivity to submucosal amiloride differed in several respects from the pattern for mucosal amiloride. The inhibition constant (K-1) was 52 mu M amiloride concentration, higher than for the apical amiloride-sensitive Na+ channel. The selectivity for Na+ over K+ was much less than for the response to mucosal amiloride; with 0.5 M NaCl or KCI on the mucosal side, the ratio of inhibition for the NaCl response to inhibition for the KCl response varied between 1 and 3.

4. As the concentration of NaCl in the mucosal solution was varied, submucosal amiloride caused little inhibition of I-sc for mucosal NaCl below isosmotic concentration, with the percent inhibi tion increasing as mucosal salt concentration increased. With 0.5 M sodium gluconate in the mucosal solution, there was very little inhibition due to submucosal amiloride.

5. The results support the presence of amiloride-sensitive Na+ channels in the basolateral membranes of the dorsal tongue epithelium in rat, and are consistent with the proposed model in which these channels are present in taste cells.

Abstract  An efficient and practical process to generate beta-C-arylglucoside derivatives was achieved. The process described involves Lewis acid mediated ionic reduction of a peracetylated 1-C-aryl methyl glucoside derived from the addition of an aryl-Li to selectively protected delta-D-gluconolactone. The reduction of the 2-acetoxy-1-C-oxacarbenium ion intermediates proceeds with a high degree of selectivity to give beta-C-arylglucosides without 2-acetoxy group participation. Furthermore, during the reduction process we also identified an unprecedented critical role of water. By changing from the usual benzyl ether protecting groups because of cost and chemical compatibility concerns, the new process is made additionally efficient and highly selective.

Abstract  Delivery systems prepared with natural biopolymers are of particular interests for applications in food, pharmaceutics and biomedicine. In this study, nanocomplex particles of sodium caseinate (NaCas) and pectin were fabricated and investigated as potential oral delivery vehicles. Nanocomplexes were prepared with three mass ratios of NaCas/pectin by acidification using glucono-δ-lactone and thermal treatment. NaCas/pectin at 1:1 mass ratio resulted in dispersions with the lowest turbidity and the smallest and most uniform nanocomplexes. Thermal treatment at 85 °C for 30 min facilitated the formation of stable, compact, and spherical nanocomplexes. Heating not only greatly increased the yield of nanocomplexes but also significantly improved the encapsulation capability of rutin studied as a model compound. Pectin in nanocomplexes delayed the hydrolysis of NaCas by pepsin at gastric conditions and enabled the controlled release of most rutin in simulated intestinal conditions. The nanocomplexes based on food-sourced biopolymers have promising features for oral delivery of nutrients and medicines.

Abstract  BACKGROUND: A new protocol for the Amicus separator (Fresenius Kabi) enables the device to perform plasma exchange (PE). The aim of the study was to compare retrospectively the plasma removal efficiency (PRE) of the Amicus, the Optia (TerumoBCT), and the Spectra (TerumoBCT) when performing PEs.

STUDY DESIGN AND METHODS: We retrospectively reviewed patients who received at least one PE with the Amicus and at least one PE with the Optia, the Spectra, or both. We collected data regarding PRE, volume of anticoagulant and calcium-magnesium (Ca-Mg) solution infused, and changes in laboratory data from patients' blood sampled immediately before starting and immediately after finishing each PE procedure: complete blood count, coagulation, acid-base equilibrium, and biochemistry variables. We also collected severe adverse events (AEs).

RESULTS: We performed 18, 44, and 14 PEs with the Amicus, Optia, and Spectra, respectively. We observed significant differences among the Amicus, Optia, and Spectra regarding PRE (79.8 ± 8.2, 82.9 ± 5.8, and 70.4 ± 8.2%; p < 0.001), volume of anticoagulant infused (542 ± 196, 687 ± 120, and 647 ± 111 mL; p = 0.002), volume of Ca-Mg solution infused (81 ± 28, 56 ± 16, and 63 ± 15 mL; p < 0.001), absolute change of ionic Ca (-0.04 ± 0.13, -0.05 ± 0.12, and -0.19 ± 0.16 mmol/L; p = 0.002), and absolute change of Na (1.18 ± 1.97, 1.02 ± 1.93, and 3.71 ± 1.98 mEq/L; p < 0.001). We observed no significant differences in other analytic variables and we observed no severe AEs.

CONCLUSION: The Amicus device could effectively perform PE procedures. In terms of PRE, the Amicus and Optia were similar, but both devices were superior to the Spectra. The Amicus used a lower volume of anticoagulant when compared with the Optia.

Abstract  The rheological behavior of electrosterically dispersed aqueous suspensions composed of submicrometer alumina and nano zirconia particles in different ratios and solids contents (from 34 to 40 vol%) has been studied during in situ coagulation casting. Glucono-delta-lactone was used as the coagulant to achieve destabilization of the ceramic suspensions by acidifying the suspension so that the pH became close to the isoelectric point for both powders. The effects of the lactone content (from 0.5 to 6.7 wt%) and the solids loading on the rheological parameters (dynamic and static measurements) during the coagulation process were studied. Dynamic measurements showed an increasing elastic modulus, G', with time and lactone content (viz. 180 and 340 kPa for 6.7 wt% lactone addition after 40 and 60 min, respectively, and 57.3 kPa for 0.5 wt% lactone after 60 min), suggesting the formation of stronger green bodies at higher additions and longer times. The conditions were optimized to yield homogeneous green samples with a uniform nanozirconia distribution and densities between 58% and 60% of the theoretical. These were subsequently sintered to yield composites with a final density up to 97%.

Abstract  Triple recycling (i.e., enterohepatic, enteric and local recycling) plays a central role in governing the disposition of phenolics such as flavonoids, resulting in low systemic bioavailability but higher gut bioavailability and longer than expected apparent half-life. The present study aims to investigate the coexistence of these recycling schemes using model bioactive flavonoid tilianin and a four-site perfused rat intestinal model in the presence or absence of a lactase phlorizin hydrolase (LPH) inhibitor gluconolactone and/or a glucuronidase inhibitor saccharolactone. The result showed that tilianin could be metabolized into tilianin glucuronide, acacetin, and acacetin glucuronide, which are excreted into the bile and luminal perfusate (highest in the duodenum and lowest in the colon). Gluconolactone (20 mM) significantly reduced the absorption of tilianin and the enteric and biliary excretion of acacetin glucuronide. Saccharolactone (0.1 mM) alone or in combination of gluconolactone also remarkably reduced the biliary and intestinal excretion of acacetin glucuronide. Acacetin glucuronides from bile or perfusate were rapidly hydrolyzed by bacterial β-glucuronidases to acacetin, enabling enterohepatic and enteric recycling. Moreover, saccharolactone-sensitive tilianin disposition and glucuronide deconjugation, which was more active in the small intestine than the colon, points to the small intestinal origin of the deconjugation enzyme and supports the presence of local recycling scheme. In conclusion, our studies have demonstrated triple recycling of a bioactive phenolic (i.e., a model flavonoid), and this recycling may have an impact on the site and duration of polyphenols pharmacokinetics in vivo.

Abstract  Clamped by the acid-resistant phenylsulfonylethylidene (PSE) acetal, D-glucal privileged the additive pathway over the Ferrier I rearrangement when confronted with protic nucleophiles. (c) 2008 Elsevier Ltd. All rights reserved.

Abstract  The effects of eight factors (solids content, fat content, fat type, order of heating, severity of heat treatment, homogenization pressure, acidification temperature and concentration of glucono-delta-lactone (GDL)) on the theological properties of acid milk gels prepared from recombined milks homogenized by microfluidization have been studied.

The gelation time (time at which G' and G '' began to increase) was reduced by low level of solids, low level of fat, high heat treatment, high incubation temperature and high concentration of acidulant. Heating the milk after homogenization, high heat treatment and high incubation temperature increased the gelation pH (the pH of the sample at gelation time).

The theological properties (elastic modulus, viscous modulus and phase angle) were influenced by level of solids, level of fat, heat treatment and incubation temperature. High level of solids and fat, high heat treatment and low incubation temperature increased both elastic and viscous moduli, but only level of fat and incubation temperature influenced phase angle. Incorporating olive oil instead of milk fat and varying homogenization pressure had no significant effects on gel initiation or viscoelastic properties.

As compared to the high pressure valve homogenizer, the microfluidizer produced smaller particles and a narrower size distribution, but the theological properties of the acid gels were very similar.

Abstract  We characterized a glucose-sensitive, controlled-release insulin delivery system. Insulin release rates increased when glucose was perfused in the release media surrounding the matrix. The system was composed of solid, particulate insulin, incorporated into an ethylene-vinyl acetate copolymer (EVAc) matrix. Feedback control was mediated by the glucose oxidase enzyme immobilized to Sepharose beads, which were incorporated along with insulin into the EVAc matrix. When glucose in solution entered the insulin delivery system, gluconic acid was produced, causing a drop in the microenvironmental pH of the matrix. This fall in pH resulted in a rise in insulin solubility and consequently a rise in the insulin release rate from the matrix. Insulin concentrations increased in vitro and in vivo in response to glucose infusion. The increased insulin release was shown to consist of a finite pulse of insulin that required an optimal recovery period of 1 h to achieve a maximal repeated response to a glucose stimulus. Repeated pulses were demonstrated over a 4 h period. An optimum enzyme ratio was also determined.

Abstract  The efficient transformation of abundant and renewable lignocellulosic biomass for the production of chemicals and fuels is of considerable importance for establishing a sustainable society. The selective catalytic conversion of the major components of lignocellulosic biomass, including cellulose, hemicellulose and lignin, into key platform chemicals under mild conditions represents an ideal route for the utilization of this abundant resource. Cellulose is composed of multiple glucose units, which are linked together through beta-1,4-glycosidic bonds, and the selective cleavage of these glycosidic bonds would therefore provide access to glucose and glucose derivatives. Hemicellulose is a heteropolysaccharide composed of different sugar units such as glucose, mannose, xylose, arabinose and galactose. The selective cleavage of the glycosidic bonds in hemicelluloses would therefore provide a mixture of different sugars. In contrast to cellulose and hemicellulose, lignin is a complex macropolymer consisting of methoxylated phenylpropane structures. Furthermore, lignin contains a variety of different C-O bond types, including beta-O-4, a-O-4 and 4-O-5 bonds, which connect the primary aromatic units in lignin. The selective cleavage of these C-O bonds would therefore lead to the formation of high-value aromatic compounds. In this review article, we have provided a detailed summary of recent advances towards the development of new catalysts and novel strategies for the selective cleavage of the C-O bonds in cellulose, hemicellulose and lignin, as well as closely related model systems, for the production of glucose, glucose derivatives (including alkyl glucosides, hexitols and gluconic acid), xylose, arabinose and aromatic compounds. The key factors determining catalytic performances have been described in detail. The reaction mechanisms have also been discussed to provide the reader with a deeper understanding of the processes involved in the selective activation of C-O bonds. (C) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.