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Strong natural bast fibers, especially flax fibers, can be used to replace glass fibers in reinforced composites. The properties of natural fibers depend largely on maturity, retting and processing. Two chemical treatments were applied to retted and semiretted flax fibers to create better fiber to resin bonding and to show the effect of retting degree and successive purification processes on the mechanical properties of natural composite materials. Retted and semiretted flax fibers have been scoured and bleached with the objective of removing surface impurities and developing finer structure. To investigate the effect of adhesion promoter on the mechanical properties of natural fiber composite, a composite sample was prepared from bleached retted flax pretreated with adhesion promoter Isostearoyltitanate (ISTT). After treatments the fibers got cleaner and the measurements showed that the fiber fineness as well as the surface free energy increased. The treatments were accompanied by decrease in the fiber tenacity but it has been found not to be reflected to the final mechanical properties of the composite. No improvement was remarked by using Isostearoyltitanate for surface modification. [ABSTRACT FROM AUTHOR]

Bifunctional starch composites were prepared by γ-induced grafting of acrylamide (Aam) and acrylic acid (AA) onto maize starch. The prepared composites were characterized by FTIR spectroscopy and scanning electron microscope (SEM). The feasibility of these composites to remove anionic dyes, direct blue 21 (D. Blue 21) and direct brown 2 (D. Brown 2) and a cationic dye, methylene blue (MB) were examined. Factors affecting adsorption of anionic and cationic dyes onto these starch composites were studied. These factors were radiation dose, agitation time, adsorbent and adsorbate concentrations. Prepared composites were effectively used in adsorption of D. Blue 2, D. Brown 2 and MB from aqueous solutions. The Adsorption data of both D. Blue 21 and D. Brown 2 complied with the Langmuir and Freundlich isotherms. [ABSTRACT FROM AUTHOR]

A new adsorbent was prepared from wood pulp (WP) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide (DMF). The adsorption of Cr (VI) from aqueous solutions by the so-prepared wood pulp adsorbent (WP-A) was investigated. Various factors affecting adsorption, such as pH, adsorbent concentration (1–5 g/L), agitation time (5–60 min), and Cr (VI) concentration (50–700), were taken into consideration. The adsorption of Cr (VI) onto (WP-A) was found to be pH-dependent and maximum adsorption was obtained at pH 3. The adsorption data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity (Q max ) was found to be 588.24 mg/g. Freundlich constants, K F and n, were found to be 55.03 and 2.835, respectively. [ABSTRACT FROM AUTHOR]

An anion exchanger ('Cell-AE') was prepared by grafting acrylonitrile (AN) onto carbon cloth waste followed by subsequent modification with hydrazine hydrate and dimethyl sulfate. The effect of radiation dose and monomer concentration was investigated. The nitrate ( NO 3 - ) and phosphate ( PO 4 3 - ) sorption potentials of the 'Cell-AE' was evaluated via batch mode. The 'Cell-AE' showed a higher adsorption affinity towards PO 4 3 - than NO 3 - . Similarly, the PO 4 3 - and NO 3 - adsorption was described by Dubinin–Radushkevich (D-R) and Redlich-Peterson (R-P) models, respectively. The present study conclusively proffered a potential mitigation approach to carbon cloth waste management. [ABSTRACT FROM AUTHOR]

Smart nanocarriers with switchable surfaces consisting of thermo-sensitive polymers and aptamers have been developed, through which the cellular uptake and photothermal therapy in five different cells could be spatial-temporally controlled on command, which is beneficial in maximizing therapy efficacy and minimizing side effects. [ABSTRACT FROM AUTHOR]

A novel luminescence probe based on mono-6-amino-β-cyclodextrin (NH2-β-CD) functionalised gold nanoclusters (β-CD-AuNC) was designed for dopamine (DA) detection. The NH2-β-CD molecules were conjugated onto the surface of 11-mercaptoundecanoic acid capped AuNCs (11-MUA-AuNC) via a carbodiimide coupling reaction. The integrity of the β-CD cavities was preserved on the surface of AuNCs and they retained their capability for molecular DA host–guest recognition. DA could be captured by the β-CD cavities to form an inclusion complex in which the oxidised DA could quench the fluorescence of the β-CD-AuNC probe by electron transfer. The probe could be used to quantify DA in the range of 5–1000 nM with a detection limit of 2 nM. This sensitivity was 1–2 orders of magnitude higher than that in previously reported methods. Interference by both ascorbic acid (AA) and uric acid (UA) was not observed. Therefore, the β-CD-AuNC probe could be directly used to determine the DA content in biological samples without further separation. This strategy was successfully applied to a DA assay in spiked human serum samples and it exhibited remarkable accuracy, sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

A novel electrochemical biosensing platform for nicotinamide adenine dinucleotide (NAD+)-dependent dehydrogenase catalysis was designed using the nitrogen-doped graphene (NG), which had properties similar to NADH dehydrogenase (CoI). NG mimicked flavin mononucleotide (FMN) in CoI and efficiently catalyzed NADH oxidation. NG also acted as an electron transport "bridge" from NADH to the electrode due to its excellent conductivity. In comparison with a bare gold electrode, an 800mV decrease in the overpotential for NADH oxidation and CoI-like behavior were observed at NG-modified electrode, which is the largest decrease in overpotential for NADH oxidation reported to date. The catalytic rate constant (k) for the CoI-like behavior of NG was estimated to be 2.3×105M−1s−1, which is much higher than that of other previously reported FMN analogs. The Michaelis-Menten constant (Km) of NG was 26μM, which is comparable to the Km of CoI (10μM). Electrodes modified with NG and NG/gold nanoparticals/formate dehydrogenase (NG/AuNPs/FDH) showed excellent analytical performance for the detection of NADH and formate. This electrode fabrication strategy could be used to create a universal biosensing platform for developing NAD+-dependent dehydrogenase biosensors and biofuel cells. [ABSTRACT FROM AUTHOR]

The expression of microRNAs (miRNAs) is related to some cancer diseases. Recently, miRNAs have emerged as new candidate diagnostic and prognostic biomarkers for detecting a wide variety of cancers. Due to low levels, short sequences and high sequence homology among family members, the quantitative miRNA analysis is still a challenge. A novel electrochemical biosensor with triple signal amplification for the ultrasensitive detection of miRNA was developed based on phosphatase, redox-cycling amplification, a bimetallic Pd–Pt supported graphene functionalized screen-printed gold electrode, and two stem-loop structured DNAs as target capturers. The proposed biosensor is highly sensitive due to the enhanced electrochemical signal of Pd–Pt supported graphene and sufficiently selective to discriminate the target miRNA from homologous miRNAs in the presence of loop-stem structure probes with T4 DNA ligase. Therefore, this strategy provided a new and ultrasensitive platform for amplified detection and subsequent analysis of miRNA in biomedical research and clinical diagnosis. [ABSTRACT FROM AUTHOR]