Consecutive Washing Research Articles

Synthesis and study of a molecularly imprinted polymer for specific solid-phase extraction of vinflunine and its metabolite from biological fluids.

A molecularly imprinted polymer (MIP) was synthesized in order to specifically extract vinflunine, an anticancer agent, and its metabolite (4-O-deacetylvinflunine) from bovine plasma and artificial urine by solid-phase extraction (SPE). Vinorelbine, a non-fluorinated analogue of vinflunine, was selected as a template for MIP synthesis. The selectivity of MIP versus the template (vinorelbine) and other alkaloids (catharanthine, vinblastine, vincristine, vinflunine and 4-O-deacetylvinflunine) was shown by a SPE protocol carried out with non-aqueous samples. A second protocol was developed for aqueous samples with two consecutive washing steps (AcOH-NH2 OH buffer (pH 7, I=10 mM)-MeOH mixture 95:5 v/v and ACN-AcOH mixture 99:1 v/v) and an elution step (MeOH-AcOH mixture 90:10 v/v). Thus, MIP-SPE of bovine plasma brought high recoveries, 81 and 89% for vinflunine and its metabolite, respectively. This protocol was slightly modified for artificial urine samples in order to obtain a good MIP/NIP selectivity; furthermore, elution recoveries were 73 and 81% for vinflunine and its metabolite, respectively. Repeatability was assessed in both biological matrices and RSD (%) were inferior to 4%. The MIP also showed a suitable linearity (r(2) superior to 0.99), between 0.25 and 10 μg/mL for plasma, and between 1 and 5 μg/mL for artificial urine.

A Microarray-based Approach Identifies ADP Ribosylation Factor-like Protein 2 as a Target of microRNA-16

microRNAs (miRNAs) are generally thought to negatively regulate the expression of their target genes by mRNA degradation or by translation repression. Here we show an efficient way to identify miRNA target genes by screening alterations in global mRNA levels following changes in miRNA levels. In this study, we used mRNA microarrays to measure global mRNA expression in three cell lines with increased or decreased levels of miR-16 and performed bioinformatics analysis based on multiple target prediction algorithms. For further investigation among the predicted miR-16 target genes, we selected genes that show an expression pattern opposite to that of miR-16. One of the candidate target genes that may interact with miR-16, ADP-ribosylation factor-like protein 2 (ARL2), was further investigated. First, ARL2 was deduced to be an ideal miR-16 target by computational predictions. Second, ARL2 mRNA and protein levels were significantly abolished by treatment with miR-16 precursors, whereas a miR-16 inhibitor increased ARL2 mRNA and protein levels. Third, a luciferase reporter assay confirmed that miR-16 directly recognizes the 3'-untranslated region (3'-UTR) of ARL2. Finally, we showed that miR-16 could regulate proliferation and induce a significant G0/G1 cell cycle arrest, which was due at least in part, to the down-regulation of ARL2. In summary, the present study suggests that integrating global mRNA profiling and bioinformatics tools may provide the basis for further investigation of the potential targets of a given miRNA. These results also illustrate a novel function of miR-16 targeting ARL2 in modulating proliferation and cell cycle progression.

Hierarchical ZSM‐5 Zeolites in Shape‐Selective Xylene Isomerization: Role of Mesoporosity and Acid Site Speciation

The isomerization of o-xylene, a prototypical example of shape-selective catalysis by zeolites, was investigated on hierarchical porous ZSM-5. Extensive intracrystalline mesoporosity in ZSM-5 was introduced by controlled silicon leaching with NaOH. In addition to the development of secondary porosity, the treatment also induced substantial aluminum redistribution, increasing the density of Lewis acid sites located at the external surface of the crystals. However, the strength of the remaining Brønsted sites was not changed. The mesoporous zeolite displayed a higher o-xylene conversion than its parent, owing to the reduced diffusion limitations. However, the selectivity to p-xylene decreased, and fast deactivation due to coking occurred. This is mainly due to the deleterious effect of acidity at the substantially increased external surface and near the pore mouths. A consecutive mild HCl washing of the hierarchical zeolite proved effective to increase the p-xylene selectivity and reduce the deactivation rate. The HCl-washed hierarchical ZSM-5 displayed an approximately twofold increase in p-xylene yield compared to the purely microporous zeolite. The reaction was followed by operando infrared spectroscopy to simultaneously monitor the catalytic performance and the buildup of carbonaceous deposits on the surface. Our results show that the interplay between activity, selectivity, and stability in modified zeolites can be optimized by relatively simple post-synthesis treatments, such as base leaching (introduction of mesoporosity) and acid washing (surface acidity modification).

Colloidal nanostructures as building blocks for macroscopic thermoelectric materials with electron-crystal phonon-glass properties

AbstractWe demonstrate the shape- and size-controlled synthesis of colloidal ∼10 nm bismuth telluride nanoparticles stabilized by organic ligands in solution. Post-synthetic ligand exchange with oleic acid allows for a quick and simple ligand removal by consecutive washing with basic ammonia solution. Mild spark plasma sintering yields a macroscopic nanostructured bulk solid with nanograins unaltered in size and shape. We present the full thermoelectric characterization with an emphasis on the thermal properties of this material. It will be shown that thus prepared nanostructured bulk solids possess significantly altered physical properties typical for materials with high surface-to-volume-ratios. These alterations have the potential to lead to improved thermoelectric performances benefiting from their phonon-glass electron-crystal behavior.

Removal of trace and major metals by soil washing with Na2EDTA and oxalate

Background, aim, and scope Various metals such as cationic metals (Cu, Pb, Zn) and anionic metals (As, Cr) often coexist in real soils, and normal soil washing techniques for the removal of cationic metals with a single-washing reagent make it rather difficult to simultaneously remove all of them. Oxalate could effectively remove anionic As and EDTA could effectively remove the cationic metals, so it was possible to remove all coexisting cationic and anionic metals by washing with the combination of Na2EDTA and oxalate. The objective of this study was to (1) discuss the possibility of removing five metals, As, Cd, Cu, Pb, and Zn, effectively from the soil by washing with Na2EDTA-combined oxalate; (2) optimized through the consecutive washing.

Antibacterial Applications of Silver Nanoparticles Synthesized by Aqueous Extract of <I>Azadirachta Indica</I> (Neem) Leaves

Silver nanoparticles are known to have bactericidal effects. A new generation of dressings incorporating antimicrobial agents like silver nanoparticles is being formulated to reduce or prevent infections. The particles can be incorporated in materials and cloth rendering them sterile. Recently, it was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Apart from being environmentally friendly process, use of Neem leaves extract might add synergistic antibacterial effect of Neem leaves to the biosynthesized nanoparticles. With this hypothesis the biosynthetic production of silver nanoparticles by aqueous extract of Neem leaves and its bactericidal effect in cotton cloth against E. Coli were studied in this work. Silver nanoparticles were synthesized by short-term (1 day) and long-term (21 days) interaction of Neem extract (20% w/v) and 0.01 M AgNO3 solution in 1:4 mixing ratio. The synthesized particles were characterized by UV visible spectroscopy, transmission electron microscopy, and incorporated into cotton disks by (i) centrifuging the disks with liquid broth containing nanoparticles, (ii) in-situ coating process during synthesis, and (iii) coating with dried and purified nanoparticles. The antibacterial property of the nanoparticles coated cotton disks was studied by disk diffusion method. The effect of consecutive washing of the coated disks with distilled water on antibacterial property was also investigated. This work demonstrates the possible use of biologically synthesized silver nanoparticles by its incorporation in cloths leading them to sterilization.

Incorporation of Block Copolymer Micelles into Multilayer Films for Use as Nanodelivery Systems

This work demonstrates the potential application of stimulus responsive block copolymer micelles as triggerable delivery systems for use within multilayer films. Cationic, pH-responsive micelles of poly[2-(dimethylamino)ethyl methacrylate-block-poly(2-(diethylamino)ethyl methacrylate)] (PDMA-PDEA) were deposited on anionic polystyrene latex particles. The charge reversal of the surface and the amount of adsorbed polymer were monitored by zeta potential measurements and colloidal titrations, respectively. Prior to adsorption, the PDMA-PDEA micelles were loaded with a hydrophobic dye, and UV-vis spectroscopy was used to determine the amount of dye encapsulated within a monolayer of micelles. It was found that subtle chemical modification of the PDMA-PDEA diblock copolymer via permanent quaternization of the PDEA block results in micelles with tunable loading capacities. Multilayers of cationic micelles of partially quaternized PDMA-PDEA and anionic polyelectrolyte (poly(sodium 4-styrene sulfonate)) were deposited on the surface of polystyrene latex particles by sequential adsorption. UV-vis analysis of the dye present within the multilayer after the addition of each layer demonstrates that the micelles are sufficiently robust to retain encapsulated dye after multiple adsorption/washing cycles and can thus create a film that can be increasingly loaded with dye as more micelle layers are adsorbed. Multiple washing cycles were performed on micellar monolayers of PDMA-PDEA to demonstrate how such systems can be used to bring about triggerable release of actives. When performing several consecutive washing steps at pH 9.3, the micelle structure of the PDMA-PDEA micelles in the monolayer is retained, resulting in only a small reduction in the amount of encapsulated dye. In contrast, washing at pH 4, the structure of the micelle layers is severely disrupted, resulting in a fast release of the encapsulated dye into the bulk. Finally, if a sufficient number of micelle/homopolyelectrolyte layers are adsorbed, it is possible to selectively dissolve the latex template, resulting in hollow capsules.

Open Sandwich FRET Immunoassay of Estrogen Receptor β in a PDMS Microfluidic Channel

Immunoassay is a fast and cost-effective protein detection method that can be applied to clinical diagnostics and biological research. Enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), and protein array chips are the most widely used immunoassay techniques for the detection of a target protein. In all of these methods, however, antibodies or antigens should be immobilized on a solid substrate. As a result, they require a long assay time for complete immunoreaction between antigens and antibodies, being limited by the diffusion kinetics. Moreover, they also require several cycles of consecutive binding and washing steps to separate free reagents from binding reagents. To overcome the problem of slow immunoreactions in conventional immunoassay techniques, we recently reported a fast and sensitive one-step immunoassay of estrogen receptor β (ERβ) using quantum dot (QD)-based fluorescence resonance energy transfer (FRET). To induce a strong FRET effect, QD was used as a fluorescence donor. FRET occurs when the electronic excitation energy of a donor chromophore is transferred to a nearby acceptor molecule via a dipole-dipole interaction between the donoracceptor pair. Conventional fluorescence dyes, which cause an appreciable overlap between the emission band of the donor and the absorption band of the acceptor, have generally been used as a donor-acceptor set. However, QD provides significant advantages over conventional fluorescence dyes, including brighter fluorescence, resistance to photobleaching, and narrow emission bands, which makes it suitable as a sensitive fluorescence donor. As a result, QD reaches a longer distance to the acceptor than conventional fluorescence dyes because of their superior optical properties. Furthermore, the QD-based FRET immunoassay of ERβ was faster (30-40 min of immunoassay time including incubation) than conventional immunoassay techniques because it does not need any solid-phase carriers and multiple washing steps for free reagent separations. In our previous work, the advantages of a QD-based FRET immunoassay in an open space were fully explored. Nonetheless, a faster reaction time and a smaller sample volume are still needed to apply this QD-based FRET immunoanalysis technique to clinical diagnostics. In the present work, a lab-on-a-chip technique, combined with the QD-based FRET immunoassay method, was used to develop a more sensitive and faster immunoanalysis technique. The lab-on-a-chip technique has several advantages over conventional bench-top techniques, such as minimal sample requirement, reduced reaction time, ease of use, improved product conversion, and reduced waste generation. In particular, the reaction time can be greatly reduced to less than a few minutes if a properly designed channel to obtain highly efficient mixing is adopted. Furthermore, only a small reaction volume is required in the lab-ona-chip analysis. An alligator-teeth-shaped poly(dimethylsiloxane) (PDMS) microfluidic channel was fabricated to obtain a fast immunoreaction between antibody and antigen under a flow condition. The detailed fabrication process for this PDMS channel has been reported elsewhere. ERβ is one of the most important breast cancer markers that are closely related with cell proliferations. The antiERβ monoclonal antibody (McAb, mouse ascites, IgM isotype; Sigma, St. Louis, MO, USA) was labeled on QD 565 using an antibody conjugation kit (Invitrogen, Eugene, OR, USA). In addition, the anti-ERβ polyclonal antibody (PcAb, rabbit immune serum, IgG; Biogenex, San Ramon, CA, USA) was labeled with AF 568 protein labeling kits (Invitrogen, Eugene, OR, USA). The formation of an open sandwich immunocomplex and its energy transfer process from QD-McAb to AF-PcAb are illustrated in Figure 1(a).

混合汚れ洗浄性への統計解析の応用

In previous studies, statistical method using distribution of detergent power and that of resistance of soil against washing was applied to analyze detergency of oily soil and solid particle soil. In this paper, this method was applied to an analysis of detergency of mixed soil. Artificially soiled cloth prepared by aqueous dispersion method was used as a mixed soil sample. Four-time consecutive washing tests were conducted under the same washing condition in Terg-O-Tometer using two kinds of detergent solution and distilled water. Change of removal efficiencies due to repetitive washing was used to determine the two distributions. Result shows that detergent power can be expressed as cumulative distribution function. In washing simulation using the cumulative distribution functions, the predicted removal efficiencies corresponded with experimental values. Moreover, the effect of soil aging on distribution of soil resistance against washing was found to move the distribution curve toward high resistance. These results show that the method using two statistical distributions can be applied to the detergency of mixed soil.

PLUTONIUM MOBILIZATION AND MATRIX DISSOLUTION DURING EXPERIMENTAL SLUDGE WASHING OF BISMUTH PHOSPHATE, REDOX, AND PUREX WASTE SIMULANTS

Consecutive washing of simulant sludges from the BiPO4 (Cycle 3), Redox, and PUREX processes shows less than 4.5% of sorbed Pu(III/IV) or Pu(VI) is mobilized during CrO4 2− dissolution by the 0.01 M NaOH + 0.01 M NaNO2 sluice or 3.0 M NaOH leach solutions to be used for sludge pretreatment at Hanford. Experimental sludge washing with 2.0 M HNO3 results in 5.8-65.5% dissolution of Pu(III/IV) or Pu(VI) from all simulants and dissolution of Nd(III), Cr(III), and Fe(III) (where present) from BiPO4 simulants. The dissolution of Pu(III/IV) and Pu(VI) from BiPO4 sludge simulants by strongly chelating media is accompanied by dissolution and reduction of Mn(IV) to a Mn(III) complex. Details of radioanalytical and spectroscopic investigations of sludge simulant washing are discussed in the context of understanding actinide behavior during alkaline leaching of radioactive sludge wastes.

NADH-Monodehydroascorbate oxidoreductase is one of the redox enzymes in spinach leaf plasma membranes

Amino acid analysis of internal sequences of purified NADH-hexacyanoferrate(III) oxidoreductase (NFORase), obtained from highly purified plasma membranes (PM) of spinach (Spinacia oleracea L.) leaves, showed 90 to 100% homology to internal amino acid sequences of monodehydroascorbate (MDA) reductases (EC 1.6.5.4) from three different plant species. Specificity, kinetics, inhibitor sensitivity, and cross-reactivity with anti-MDA reductase antibodies were all consistent with this identification. The right-side-out PM vesicles were subjected to consecutive salt washing and detergent (polyoxyethylene 20 dodecylether and 3-[(3-cholamido-propyl)-dimethylammonio]-1-propane sulfonate [CHAPS]) treatments, and the fractions were analyzed for NFORase and MDA reductase activities. Similar results were obtained when the 300 mm sucrose in the homogenization buffer and in all steps of the salt-washing and detergent treatments had been replaced by 150 mm KCl to mimic the conditions in the cytoplasm. We conclude that (a) MDA reductase is strongly associated with the inner (cytoplasmic) surface of the PM under in vivo conditions and requires washing with 1.0 m KCl or CHAPS treatment for removal, (b) the PM-bound MDA reductase activity is responsible for the majority of PM NFORase activity, and (c) there is another redox enzyme(s) in the spinach leaf PM that cannot be released from the PM by salt-washing and/or CHAPS treatment. The PM-associated MDA reductase may have a role in reduction of ascorbate in both the cytosol and the apoplast.