EASY CELLULOSE NANOFIBER EXTRACTION FROM RESIDUE OF AGRICULTURAL CROPS

Cellulose is found in the cell wall of plant fibers in the form of nanofibers. The Young’s modulus of the crystalline portion is close to 140 GPa whereas the tensile strength of nanofibers is estimated to be above 2 GPa. Cellulose nanofiber has the potential to become an environmentally benign substitute for conventional reinforcements, but the overall cost of production is prohibitive due to the high energy demand and low yields of the mainstream processes, along the need of expensive devices for proper extraction. This study proposes the use of an affordable kitchen blender adapted to extract cellulose nanofiber from agricultural crop byproducts to reduce production cost. Preliminary results showed that blending of pulp fibers from grass straw produces nanofibers similar to commercially available morphologies. So far the raw material for nanofiber extraction has been mainly pulp fibers from wood, but the availability of cellulose in plant cells other than fibers would make nanofibers accessible to a wider research community and accelerate the development of cellulose-based nanocomposites

Cellulose nanofiber aerogel production and applications

Aerogels are highly porous solids formed by replacing the liquid in a gel by air, without changing the original structure. The present cellulose aerogels are made by sublimating the water from a colloidal suspension of cellulose nanofibers. The nanofibers form three-dimensional networks, crosslinked by hydrogen bonds bridging the surface hydroxyl groups and also by mechanical entanglements between nanofibers. Although the studies on aerogels from cellulose nanofiber hydrogels by freeze drying reported so far had produced small samples, improved cooling techniques that produces larger samples were attempted and the obtained cellulose nanofiber aerogels were impregnated with epoxy resin to fabricate composites. The highly porous structure allowed complete impregnation of resin and translucent composites were produced. The modulus of composites was increased in relation to neat epoxy, but due to high brittleness the ultimate strength was decreased. This is likely caused by nanofiber agglomerations of uneven pore sizes acting as stress concentrators. The evaluation of the mechanical properties of composites serves as an indirect way to assess the quality of the aerogels produced

EXTRACTION OF CELLULOSE NANOFIBER FROM PARENCHYMA CELLS OF AGRICULTURAL RESIDUES

Cellulose nanofiber is an environmentally friendly reinforcing phase extractable from plants, with potential application in composites. Due to the cell wall structure differences, plant parenchyma cells might be easier to nanofibrillate than sclerenchyma cells of wood pulp fibers, resulting in lower extraction costs. This study assessed the extraction of nanofibers from residues like corn husk, banana peel, cabbage leaf, and taro leaf using a kitchen blender. Fibrillation was evaluated based on the strength of paper-like sheets produced from the nanofibers. Corn husk was nanofibrillated by the shortest blending time among the sources considered, and delivered the highest sheet strength. The blending time needed was significantly shorter than that needed to fibrillate hardwood pulp fibers

Concentration Variations of Air Pollutants Observed at Kashiwazaki Environmental Air Quality Monitoring Station

Concentration variations of air pollutants observed from April 1990 through December 2007 at the Kashiwazaki Air Quality Monitoring Station in Niigata Prefecture were analyzed. While annual mean concentrations of NO and NO_2 showed no remarkable trends, those of SPM were in clear downward trends, and Ox was in an upward trend. On the other hand, those of SO_2 decreased remarkably from 1990 to 2001, however, they have increased slightly in recent years. Monthly averaged concentrations of Ox are higher from February through May and hourly concentrations show a peak around 2 to 3 pm. The daily average concentrations of Ox were higher on Saturdays and Sundays, which is known as the weekend effect. Monthly average concentrations of NO and NO_2 were higher from November through December and hourly concentrations showed diurnal variations with peaks in the morning and evening. Monthly mean concentrations of SPM were higher from April through August and hourly concentrations are higher from 7 to 9 pm. The maximum concentrations of SO_2, SPM and Ox during the period investigated were recorded at an exceptional time, influenced by the eruption of the Miyake-jima volcano, by the Kosa phenomenon, and also the occurrence of the long-range transport of air pollutants from the continental area

Perspective on Therapeutic Strategies of Leukemia Treatment — Focus on Arsenic Compounds

Leukemia is a type of cancer of the body’s blood-forming tissues, including the bone marrow and the lymphatic system. Treatments for leukemia are complex, depending upon the type of leukemia and other factors. Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) and accounts for approximately 10-15% of all cases of AML in adults. Arsenic and its compounds are widely distributed in the environment and have been used medicinally for over 2,000 years. In fact, investigators from China and the USA have demonstrated that treatment with ATO (As2O3, AsIII) results in complete remission in 90% of relapsed APL patients since mid-1990s. Moreover, As2S2 or As4S4, also known as realgar, has been gaining increasing attention and is traditionally used to treat certain types of hematological disorders including chronic myeloid leukemia (CML), AML, myelodysplastic syndrome (MDS) and MDS/AML in China. In this chapter, we first highlight the pharmacokinetics of ATO and realgar in leukemia patients and/or healthy volunteer. We will further summarize the detailed mechanisms underlying the cytocidal effects of these arsenic compounds. We also provide detailed insight into potential future clinical application of those promising candidates endowed with potent antitumor activities in view of combination with arsenic compounds

Polylactic Acid Reinforced with Mixed Cellulose and Chitin Nanofibers : Effect of Mixture Ratio on the Mechanical Properties of Composites

The development of all-bio-based composites is one of the relevant aspects of pursuing a carbon-neutral economy. This study aims to explore the possibility to reinforce polylactic acid by the combination of cellulose and chitin nanofibers instead of a single reinforcement phase. Polylactic acid colloidal suspension, cellulose and chitin nanofiber suspensions were mixed using only water as mixing medium and subsequently dewatered to form paper-like sheets. Sheets were hot pressed to melt the polylactic acid and form nanocomposites. The combination of cellulose and chitin nanofiber composites delivered higher tensile properties than its counterparts reinforced with cellulose or chitin nanofibers alone. Cellulose and chitin appear to complement each other from the aspect of the formation of a rigid cellulose nanofiber percolated network, and chitin acting as a compatibilizer between hydrophobic polylactic acid and hydrophilic cellulose

Transforming growth factor α protects against Fas-mediated liver apoptosis in mice

AbstractThe Fas/Fas ligand interaction plays a crucial role in various liver diseases, and administration of agonistic anti-Fas antibody to mice causes massive hepatic apoptosis and fulminant hepatic failure. Several growth factors have recently been found to function in preventing apoptosis. In this study, we demonstrated that overexpression of transforming growth factor α (TGFα) has a dramatic protective effect on Fas-mediated hepatic apoptosis at the biochemical and histological levels. Moreover, 85.7% (six out of seven) of TGFα transgenic mice survived the lethal liver damage, whereas all wild-type mice died. Expression of Bcl-xL, an anti-apoptotic protein, was greatly increased in the transgenic mice. Taken together, our findings suggest that TGFα protects against Fas-mediated liver apoptosis in vivo and up-regulation of Bcl-xL may participate in protective effect of TGFα

Overexpression of hepatocyte growth factor/scatter factor promotes vascularization and granulation tissue formation in vivo

AbstractThe effect of hepatocyte growth factor/scatter factor (HGF/SF) during wound healing in the skin was investigated, using HGF/SF-overexpressing transgenic mouse model. Histological analysis of HGF/SF transgenic mouse excisional wound sites revealed increased granulation tissue with marked vascularization. Northern blot analysis demonstrated that, relative to control, vascular endothelial growth factor (VEGF) expression in transgenic skin was significantly higher at baseline and was robustly up-regulated during wound healing. Elevated levels of VEGF protein were detected immunohistochemically, predominantly in endothelial cells and fibroblasts within the granulation tissue of HGF/SF transgenic skin. Serum levels of VEGF were also elevated in HGF/SF transgenic mice. Thus, results from our study suggest that HGF/SF has a significant effect on vascularization and granulation tissue formation during wound healing in vivo, involving with induction of VEGF

Poly[(3-hexylthiophene)-block-(3-semifluoroalkylthiophene)] for Polymer Solar Cells

We report the synthesis of poly[(3-hexylthiophene)-block-(3-(4,4,5,5,6,6,7,7,7-nonafluoroheptyl)thiophene)], P(3HT-b-3SFT), carried out by the Grignard Metathesis Method (GRIM). The copolymers composition was determined by 1H and 19F NMR spectroscopies, and gel permeation chromatography (GPC). The thin films of P(3HT-b-3SFT) were investigated by ultraviolet-visible absorption spectroscopy and atomic force microscopy (AFM). We also fabricated bulk-hetero junction (BHJ) solar cells based on blends of P(3HT-b-3SFT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Although the composition ratio of P3SFT in P(3HT-b-3SFT) was low, the influence of P3SFT on the morphology and properties of solar cells was significant. The annealing process for the BHJ solar cells induced the formation of large domains and led to poor solar cell performance. The BHJ solar cells, based on PCBM and P(3HT-b-3SFT), prepared by the non-annealing process, had a maximum power conversion efficiency of 0.84% under 100 mW/cm2 (AM 1.5 solar illumination) in air

Identification of RNF213 as a Susceptibility Gene for Moyamoya Disease and Its Possible Role in Vascular Development

もやもや病感受性遺伝子の特定とその機能についての発見. 京都大学プレスリリース. 2011-7-21.Background Moyamoya disease is an idiopathic vascular disorder of intracranial arteries. Its susceptibility locus has been mapped to 17q25.3 in Japanese families, but the susceptibility gene is unknown. Methodology/Principal Findings Genome-wide linkage analysis in eight three-generation families with moyamoya disease revealed linkage to 17q25.3 (P<10-4). Fine mapping demonstrated a 1.5-Mb disease locus bounded by D17S1806 and rs2280147. We conducted exome analysis of the eight index cases in these families, with results filtered through Ng criteria. There was a variant of p.N321S in PCMTD1 and p.R4810K in RNF213 in the 1.5-Mb locus of the eight index cases. The p.N321S variant in PCMTD1 could not be confirmed by the Sanger method. Sequencing RNF213 in 42 index cases confirmed p.R4810K and revealed it to be the only unregistered variant. Genotyping 39 SNPs around RNF213 revealed a founder haplotype transmitted in 42 families. Sequencing the 260-kb region covering the founder haplotype in one index case did not show any coding variants except p.R4810K. A case-control study demonstrated strong association of p.R4810K with moyamoya disease in East Asian populations (251 cases and 707 controls) with an odds ratio of 111.8 (P = 10−119). Sequencing of RNF213 in East Asian cases revealed additional novel variants: p.D4863N, p.E4950D, p.A5021V, p.D5160E, and p.E5176G. Among Caucasian cases, variants p.N3962D, p.D4013N, p.R4062Q and p.P4608S were identified. RNF213 encodes a 591-kDa cytosolic protein that possesses two functional domains: a Walker motif and a RING finger domain. These exhibit ATPase and ubiquitin ligase activities. Although the mutant alleles (p.R4810K or p.D4013N in the RING domain) did not affect transcription levels or ubiquitination activity, knockdown of RNF213 in zebrafish caused irregular wall formation in trunk arteries and abnormal sprouting vessels. Conclusions/Significance We provide evidence suggesting, for the first time, the involvement of RNF213 in genetic susceptibility to moyamoya disease