Lignin/PVA hydrogel with enhanced structural stability for cationic dye removal

In this study, a lignin-based hydrogel for wastewater treatment was prepared by incorporating kraft lignin (KL) into a poly (vinyl alcohol) (PVA) matrix. The underwater structural stability of the KL-PVA hydrogel was guaranteed through physicochemical crosslinking, involving freeze-thaw process and chemical crosslinking reaction. The KL-PVA hydrogel displayed superior compressive characteristics compared to the original PVA hydrogel. This improvement was attributed to the chemical crosslinking and the reinforcing effect of the incorporated KL microparticles. The incorporation of anionic KL microparticles into the PVA three-dimensional network structure enhanced the cationic methylene blue (MB) and crystal violet (CV) adsorption efficiency of the prepared KL-PVA hydrogel. The MB adsorption results were well explained by pseudo-2nd order kinetics model and Langmuir isotherm model. Electrostatic forces, hydrogen bonding and π-π stacking interactions were the main adsorption mechanisms between cationic dyes and KL surfaces, indicating the potential of KL-PVA hydrogel as an effective adsorption material. Moreover, regulating the molecular weight of PVA not only prevented lignin leakage from the KL-PVA hydrogel but also elevated the KL content within the hydrogel, consequently improving its dye removal performance. For KL-PVA hydrogel with high molecular weight PVA, the MB and CV adsorption capacities were 193.8 mg/g and 190.0 mg/g, respectively.

Fabrication of transparent cellulose nanofibril composite film with smooth surface and ultraviolet blocking ability using hydrophilic lignin

Ecofriendly multifunctional films with only biomass-based components have gathered significant interest from researchers as next-generation materials. Following this trend, a TEMPO-oxidized cellulose nanofibril (TOCNF) film containing hydrophilic lignin (CL) was fabricated. To produce the lignin, peracetic acid oxidation was carried out, leading to the introduction of carboxyl groups into the lignin structure. By adding hydrophilic lignin, various characteristics (e.g., surface smoothness, UV protection, antimicrobial activity, and barrier properties) of the TOCNF film were enhanced. In particular, the shrinkage of CNF was successfully prevented by the addition of CL, which is attributed to the lower surface roughness (Ra) from 18.93 nm to 4.99 nm. As a result, the smooth surface of the TOCNF/CL film was shown compared to neat TOCNF film and TOCNF/Kraft lignin composite film. In addition, the TOCNF/CL film showed a superior UV blocking ability of 99.9 % with high transparency of 78.4 %, which is higher than that of CNF-lignin composite films in other research. Also, water vapor transmission rate was reduced after adding CL to TOCNF film. Consequently, the developed TOCNF/CL film can be potentially utilized in various applications, such as food packaging.

Biodegradable and hydrophobic nanofibrous membranes produced by solution blow spinning for efficient oil/water separation

The development of nanofibrous oil-water separation materials is explosively progressing, but the remarkably low productivity is the main factor hindering their practical application. In this study, biodegradable polybutylene succinate (PBS) nanofibers with excellent productivity (27.0 g/h per nozzle) were successfully fabricated using the solution blow spinning (SBS) process, breaking away from the conventional electrospinning method. The prepared PBS nanofibers exhibited extremely thin fiber diameters (130 nm) with high porosity (97.4%). Without any chemical modification or inorganic/organic hybrid materialization, the PBS nanofibrous membrane showed excellent oil adsorption capacity (minimum: 18.7 g/g and maximum: 38.5 g/g) and separation efficiency; water and oil mixtures (99.4-99.98%) and emulsions (98.1-99.5%) compared to conventional organic polymer-based nanofibers. In terms of disposal after use, this biodegradable nanofibrous membrane was able to return to nature through hydrolysis and biodegradation processes.

Eco-friendly alkaline lignin/cellulose nanofiber drying system for efficient redispersion behavior

Although nanocellulose is an eco-friendly, high-performance raw material provided by nature, the agglomeration of nanocellulose that occurs during the drying process is the biggest obstacle to its advanced materialization and commercialization. In this study, a facile and simple nanocellulose drying system was designed using lignin, which is self-assembled together with cellulose in natural wood, as an eco-friendly additive. The addition of lignin not only minimized aggregation during the drying and dehydration process of nanocellulose but also ensured excellent redispersion kinetics and stability. In addition, the added lignin could be removed through a simple washing process. Through FTIR, XRD, TGA, tensile and swelling tests, it was confirmed that the addition of lignin enabled the reversible restitution of the nanocellulose physicochemical properties to the level of pristine never-dried nanocellulose in drying, redispersion, and polymer processing processes.

Comparison of pyrolytic products produced from inorganic-rich and demineralized rice straw (Oryza sativa L.) by fluidized bed pyrolyzer for future biorefinery approach

The objectives of this study were to investigate the effects of inorganic constituents on the fast pyrolysis of the biomass and to determine the yields as well as physicochemical properties of pyrolytic products. The pyrolytic products were obtained from raw and demineralized rice straw using a fluidized bed type pyrolyzer at different temperatures. As pyrolysis temperature increased, total biooil yield gradually decreased from 46.6 to 29.6 wt.% for the raw-straw, and from 55.4 to 35.3 wt.% for the demineralized rice straw. For demineralized rice straw, higher pyrolysis temperatures promoted gasification reactions but reduced char formations. However, char yield for the raw-straw was relatively unaffected by temperature due to an increase in carbonization reactions that were catalyzed by some inorganics. Certain inorganic constituents in the biomass were distinctively distributed in the biooil, and ICP-ES and GC/MS analysis indicated that some inorganics may be chemically bound to cell wall components.

Developmental expression and subcellular distribution of synaptotagmin 11 in rat hippocampus

Synaptotagmins are required for Ca(2+)-dependent membrane-trafficking in either neuronal synaptic vesicles or cellular membranes. Previous reports suggested that the synaptotagmin 11 (syt11) gene is involved in the development of schizophrenia based on the genomic analysis of patients. Parkin protein binds to the C2 domains of Syt11 which leads to the polyubiquitination of Syt11. However, where and how Syt11 performs its role in the brain is largely unknown. Here, we report that Syt11 is expressed mainly in the brain. In addition, exogenously expressed Syt11 in HEK293 cells can form higher molecular weight complex via its transmembrane domain. Also, Syt11 is targeted to both dendrite and axon compartments. Immunocytochemistry showed that Syt11 is juxtaposed to postsynaptic markers in both excitatory and inhibitory synapses. Both neuroligin 1 and 2, which are postsynaptic cell adhesion molecules and differentially induce excitatory and inhibitory presynapses, respectively, recruit Syt11 in neuron coculture. Immunogold electron microscopy analysis revealed that Syt11 exists mainly in presynaptic neurotransmitter vesicles and plasma membrane, and rarely in postsynaptic sites. These results suggest that Syt11 may contribute to the regulation of neurotransmitter release in the excitatory and inhibitory presynapses, and postsynapse-targeted membrane trafficking in dendrites.

Organosolv pretreatment with various catalysts for enhancing enzymatic hydrolysis of pitch pine (Pinus rigida)

Three different types of catalysts were evaluated for organosolv pretreatment with pitch pine (Pinus rigida). Sulfuric acid, magnesium chloride, and sodium hydroxide for acid, neutral and base catalysts, respectively, were used, and ethanol was the organic solvent. The pretreatment process was conducted at different temperatures and times. The enzymatic hydrolysis process followed to estimate the digestibility of the biomass. The digestibility of pitch pine by pretreatment process with 1% sulfuric acid at the optimal condition was approximately 55-60%, and that by 1% magnesium chloride was nearly 60%. The pretreatment with 1% sodium hydroxide had no effect on digestibility at 10%, but the digestibility improved by more than 80% when the concentration was increased to 2%. Theoretical ethanol yield was the highest at organosolv pretreatment with sulfuric acid at 70% and the lowest with sodium hydroxide at 45%.

A new triterpene lactone from the roots of Patrinia scabiosaefolia

A new triterpene lactone named patrinolide A (1) has been isolated from the roots of Patrinia scabiosaefolia (Valerianaceae). Its structure was determined to be 11beta,21beta-dihydroxy-3-oxooleanan-28,13beta-olide on the basis of spectral analysis, including 2D-NMR techniques. Key words: Patrinia scabiosaefolia, Valerianaceae, Lactone, Patrinolide, 11beta,21beta-dihydroxy-3-oxooleanan-28,13beta-olide.

Protection of rat hepatocytes exposed to CCl4 in-vitro by cynandione A, a biacetophenone from Cynanchum wilfordii

To identify hepatoprotective agents from plant sources we use primary cultures of rat hepatocytes injured by CCl4. The hepatoprotective agents are the compounds that mitigate the injury caused by CCl4. Using this system we have investigated the biochemical mechanisms involved in the hepatoprotective activity of cynandione A, a biacetopherone, isolated from the roots of Cynanchum wilfordii Hemsley (Asclepiadaceae). Cynandione A (50 microM) significantly reduced (approximately 50%) the release into the culture medium of glutamic pyruvic transaminase and sorbitol dehydrogenase from the primary cultures of rat hepatocytes exposed to CCl4. Glutathione, superoxide dismutase, catalase and glutathione reductase play important roles in the cellular defence against oxidative stress. Cynandione A appeared to protect primary cultured rat hepatocytes exposed to CCl4 from significant drops in the levels of each of these four specific markers. Cynandione A also ameliorated lipid peroxidation by up to 50% as demonstrated by a reduction in the production of malondialdehyde. These results suggest that cynandione A protected the hepatocytes from CCl4-injury by maintaining the level of glutathione and by inhibiting the production of malondialdehyde, due to its radical scavenging properties.

Cynandione A from Cynanchum wilfordii protects cultured cortical neurons from toxicity induced by H2O2, L-glutamate, and kainate

Oxidative stress has been implicated as a primary cause of neuronal death in certain neurodegenerative disorders and in aging brains. Natural products have been used in Asian societies for centuries for treating such neurodegenerative disorders as senile dementia. In an effort to identify active neuroprotective compounds from these products, we have employed cultures of rat cortical neurons as our screening system. A methanolic extract from dried roots of Cynanchum wilfordii Hemsley (Asclepiadaceae) significantly mitigated the neurotoxicity induced by H2O2 in this screening system. Activity-guided fractionation using several chromatographic techniques resulted in the isolation of the neuroprotective compound, cynandione A, a biacetophenone. At a concentration of 50 microM, cynandione A significantly reduced neurotoxicity induced by H2O2. Cynandione A significantly attenuated decreases in levels of glutathione, superoxide dismutase, and other enzymes that participate in the cellular defense against oxidative stress. Furthermore, cynandione A alleviated neurotoxicity induced by the excitotoxic neurotransmitter, L-glutamate, the neurotoxicity induced by kainate, but not that mediated by N-methyl-D-aspartate. Cynandione A was demonstrated to be a natural antioxidant as it facilitated the breakdown of hydrogen peroxide in vitro; however, no mechanism was uncovered to explain its neuroprotectant effects against glutamate and kainate. Therefore, cynandione A may be efficacious in protecting neurons from oxidative stress mediated via activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate/kainate receptors since it exerted significant neuroprotective effects on cultured cortical neurons.

Enzymatic synthesis of a dihydrobenzofuran neolignan by oxidative coupling

The oxidative dimerization of ferulic acid has been carried out using horse-radish peroxidase as catalyst to give a dihydrobenzofuran neolignan (1), the structure of which was elucidated as (2SR,3RS)-2,3-dihydro-2-(4-hydroxy-3-methoxyphenyl)-3-n-buto xycarbonyl-5-(2E-carboxyethenyl)-7-methoxybenzofuran by spectroscopic analyses. This compound showed more potent cytotoxicity against several tumor cell lines than the starting material.

Uncarinic acids: phospholipase Cgamma1 inhibitors from hooks of Uncaria rhynchophylla

Bioactivity-guided fractionation of the CHCl3 extract from hooks of Uncaria rhynchophylla led to the isolation of two triterpene esters, namely uncarinic acids A (1) and B (2). Their structures were established by spectroscopic and chemical methods. These compounds inhibited phospholipase Cgamma1 with IC50 values of 35.66 and 44.55 microM, respectively.

Steroidal glycosides of the 14,15-seco-18-nor-pregnane series from Cynanchum ascyrifolium

Three new steroidal glycosides named cynascyrosides A-C were isolated from the roots of Cynanchum ascyrifolium. The structures of these compounds were determined on the basis of spectroscopic and chemical evidence as cynajapogenin A 3-O-alpha-D-oleandropyranosyl-(1-->4)-beta-L-cymaropyranosyl -(1-->4)-beta-D- digitoxopyranoside; cynajapogenin A 3-O-beta-D-glucopyranosyl-(1-->4)-alpha-L-cymaropyranosyl- (1-->4)-beta-L-cymaropyranosyl-(1-->4)-beta-L-cymaropyranoside+ ++; cynajapogenin A 3-O-beta-D-glucopyranosyl-(1-->4)-alpha-L-cymaropyranosyl- (1-->4)-beta-D-digitoxopyranosyl-(1-->4)-beta-L-cymaropyranosid e.

RADIOLOGICAL AND SURVIVAL COMPARISON OF FOUR METHODS OF FIXATION OF A PROXIMAL FEMORAL STEM

We compared the radiological appearances and survival of four methods of fixation of a femoral stem in 538 hips after follow-up for five or ten years. The fixation groups were: 1) press-fit shot-blasted smooth Ti-Al-V stem; 2) press-fit shot-blasted proximally ridged stem; 3) proximal hydroxyapatite (HA) coating; and 4) cementing.

Survival analysis at five to ten years showed better results in the HA-coated (100% at five to six years) and cemented stems (100% at 5 to 6 years) than in the two press-fit groups. There was a higher mean rate of migration in the smooth and ridged Ti-Al-V shot-blasted press-fit groups (0.8 mm/year and 0.6 mm/year, respectively) when compared with the HA-coated and cemented prostheses (both 0.3 mm/year). More radiolucent lines and osteolytic lesions were seen in the press-fit groups than in either the HA-coated or cemented implants, with a trend for a lower incidence of both in the HA compared with the cemented group. Proximal osteopenia increased in the press-fit and cemented prostheses with time, but did not do so in the HA group. There was a higher incidence of resorption of the femoral neck with time in the cemented group than in the other three.

We conclude that the HA and the cemented interfaces both provide secure fixation with a trend in favour of HA. The cemented prosthesis meets the suggested National Institutes of Health definition of ‘efficacious’ at ten years.

Radiological and survival comparison of four methods of fixation of a proximal femoral stem

We compared the radiological appearances and survival of four methods of fixation of a femoral stem in 538 hips after follow-up for five or ten years. The fixation groups were: 1) press-fit shot-blasted smooth Ti-A1-V stem; 2) press-fit shot-blasted proximally ridged stem; 3) proximal hydroxyapatite (HA) coating; and 4) cementing. Survival analysis at five to ten years showed better results in the HA-coated (100% at five to six years) and cemented stems (100% at 5 to 6 years) than in the two press-fit groups. There was a higher mean rate of migration in the smooth and ridged Ti-A1-V shot-blasted press-fit groups (0.8 mm/year and 0.6 mm/year, respectively) when compared with the HA-coated and cemented prostheses (both 0.3 mm/year). More radiolucent lines and osteolytic lesions were seen in the press-fit groups than in either the HA-coated or cemented implants, with a trend for a lower incidence of both in the HA compared with the cemented group. Proximal osteopenia increased in the press-fit and cemented prostheses with time, but did not do so in the HA group. There was a higher incidence of resorption of the femoral neck with time in the cemented group than in the other three. We conclude that the HA and the cemented interfaces both provide secure fixation with a trend in favour of HA. The cemented prosthesis meets the suggested National Institutes of Health definition of 'efficacious' at ten years.

N2-methyl-8-oxoguanine: a tRNA urinary metabolite--role of xanthine oxidase

DNA damage produces a series of oxidation products including 8-oxo-2'-deoxyguanosine and 8-oxoguanine, whose urinary excretion have been used to estimate in vivo oxidative injury. A monoclonal antibody to 8-oxoguanine was used to measure these adducts in urine taken from ill infants. In the process of this investigation we observed a large chromatographic peak that did not correspond to any of the known 8-oxoguanine adducts. A combination of liquid chromatography with electrochemical detection and gas chromatography/mass spectrometry allowed isolation and identification of the previously undescribed oxidation product, N2-methyl-8-oxoguanine. The excretion of this compound is increased in ill and growing infants but is also found in the urine of adult rats and humans. Experiments with allopurinol, a xanthine oxidase inhibitor, show that in humans, N2-methyl-8-oxoguanine is formed from the tRNA modified base N2-methylguanine. This is in contrast to the nonmethylated bases, which are converted to 8-oxo derivatives as a result of oxidative damage to nucleic acids and do not appear to be substrates for xanthine oxidase.

Surgical intervention for the repair of exomphalos

Exomphalos carries a 67% chance of other serious defects, 37% of which are life-threatening. Diagnosis in utero means parents can be counselled and offered choices of treatment. Parents need long-term support if their baby has a syndrome or other abnormalities. Babies that survive do well and most lead normal lives.

Chalk in the prime

After observations of cloudiness in the perfusion circuit at open intracardiac operations, laboratory experiments showed a precipitate in a Hartmann's solution (compound sodium lactate solution, Ringer-lactate) and sodium bicarbonate based priming fluid used for cardiopulmonary bypass. The precipitate was found to consist of calcium carbonate crystals. The crystals were not dissolved by adding plasma proteins, nor were they sufficiently cleared from the extracorporeal circuit by a 40 microns filter in the arterial line. The crystals may embolise in microvascular beds and thus be a cause of postoperative morbidity. The practice of adding sodium bicarbonate to the pump prime may be unnecessary.

The preparation of ethyl and isopropyl dienol ethers and dienol pivalate esters from Hagemann's ester and its t-butyl analogue, and the reactions of the derived ester dienolates with electrophiles

The preparation of ethyl 4-ethoxy-2-methylcyclohexa-1,3-diene-1-carboxyate, ethyl 4-isopropoxy- 2-methylcyclohexa-1,3-diene-1-carboxylate, t-butyl 4-isopropoxy-2-methylcyclohexa-1,3-diene-1- carboxylate, ethyl 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate, and t-butyI 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate from Hagemann's ester and its t-butyl analogue in the presence of diethyl or diisopropyl sulfates and sodium hydride in dimethyl sulfoxide, or pivaloyl chloride and N,N,N',N'-tetramethylethylenediamine in tetrahydrofuran is described. The foregoing dienol ethers and esters are smoothly deprotonated by lithium diisopropyl- amide in tetrahydrofuran at -78" to give the corresponding ester dienolates, which react regio- specifically with a number of electrophiles, either a or y to the alkoxycarbonyl group of the dienol ether or ester. A number of the products, which are generally obtained in good yields, have been hydrolysed to Hagemann's ester derivatives substituted exclusively at C1.