Structural Characterization of Anticancer Drug Paclitaxel and Its Metabolites Using Ion Mobility Mass Spectrometry and Tandem Mass Spectrometry

Paclitaxel (PTX) is a popular anticancer drug used in the treatment of various types of cancers. PTX is metabolized in the human liver by cytochrome P450 to two structural isomers, 3'-p-hydroxypaclitaxel (3p-OHP) and 6 alpha-hydroxypaclitaxel (6 alpha-OHP). Analyzing PTX and its two metabolites, 3p-OHP and 6 alpha-OHP, is crucial for understanding general pharmacokinetics, drug activity, and drug resistance. In this study, electrospray ionization ion mobility mass spectrometry (ESI-IM-MS) and collision induced dissociation (CID) are utilized for the identification and characterization of PTX and its metabolites. Ion mobility distributions of 3p-OHP and 6 alpha-OHP indicate that hydroxylation of PTX at different sites yields distinct gas phase structures. Addition of monovalent alkali metal and silver metal cations enhances the distinct dissociation patterns of these structural isomers. The differences observed in the CID patterns of metalated PTX and its two metabolites are investigated further by evaluating their gas-phase structures. Density functional theory calculations suggest that the observed structural changes and dissociation pathways are the result of the interactions between the metal cation and the hydroxyl substituents in PTX metabolites.1155Ysciescopu

Whispering-gallery-modelike-enhanced emission from ZnO nanodisk

Hexagonal nanodisks of ZnO were fabricated by a solution process using ZnO nanoparticles and their cathodoluminescence characteristics were investigated. Monochromatic cathodoluminescence images showed that luminescence was spatially localized near the boundary of the nanodisk and spectral analysis in conjunction with the intensity profile consistently ascribed the spatial localization of luminescence to whispering-gallery-modelike-enhanced emission.open117682sciescopu

Plasmonic Nano-Rotamers with Programmable Polarization-Resolved Coloration

3D-shaped artificial Mg nano-rotamers with a programmable dihedral angle between two plasmonic arms, designed to exhibit both programmable linear and circular polarization properties, are presented. The nanoscale physical shadow growth technique offers precise control over the angular alignment in these nanostructures with 1° angular precision, thus controlling their symmetry from achiral C2v and C2h to chiral C2. As a result, they give rise to a wide range of polarization-resolved coloration, spanning from invisible to visible colors with 46% transmission contrast for linear polarization while exhibiting 0.08 g-factor in visible for circular polarization. These nano-rotamers hold great potential for various applications in adaptive photonic filters, memory, and anticounterfeiting devices, benefiting from their tunable plasmonic properties

Effect of B on the microstructure and mechanical properties of mechanically milled TiAl alloys

The present study is concerned with gamma-(Ti52Al48)(100-x)B-x (x = 0, 0.5, 2, 5) alloys produced by mechanical milling/vacuum hot pressing (VHPing) using melt-extracted powders. Microstructure of the as-vacuum hot pressed (VHPed) alloys exhibits a duplex equiaxed microstructure of alpha(2) and gamma with a mean grain size of 200 nm. Besides alpha(2) and gamma phases, binary and 0.5 pet B alloys contain Ti,AIN and Al2O3 phases located along the grain boundaries and show appreciable coarsening in grain and dispersoid sizes during annealing treatment at 1300 degrees C for 5 hours. On the other hand, 2 pet B and 5 pet B alloys contain fine boride particles within the gamma grains and shaw minimal coarsening during annealing. Room-temperature compressing tests of the as-VHPed alloys show low ductility, but very high yield strength > 2100 MPa. After annealing treatment, mechanically milled alloys show much higher yield strength than conventional powder metallurgy and ingot metallurgy processed alloys, with equivalent ductility to ingot metallurgy processed alloys. The 5 pet B alloy with the smallest grain size shows higher yield strength than binary alloy up to the test temperature of 700 degrees C. At 850 degrees C, 5 pet B alloy shows much lower strength than the binary alloy, indicating that the deformation of fine 5 pet B alloy is dominated by the grain boundary sliding mechanism.ope

Adsorption and photocatalysis kinetics of herbicide onto titanium oxide and powdered activated carbon

The adsorption and photocatalysis kinetics of metsulfuron-methyl (MM) onto titanium oxide (TiO2) and powdered activated carbon (PAC) were studied at varying adsorbent amount and MM concentration. The overall mass transfer in adsorption was estimated from concentration decay curves obtained in the batch adsorber. The maximum adsorption capacity decreased with increasing adsorbent amount in TiO2 adsorption. The adsorption isotherms of MM could be plotted using the Langmuir isotherm model with a reasonable degree of accuracy having higher r2 values rather than Freundlich isotherm model. Linear driving force approximation (LDFA) kinetic equation with Langmuir adsorption isotherm model was successfully applied to predict the adsorption kinetics data in various concentrations of MM in photobatch reactor. The estimated mass transfer coefficient was used to be 3.0 × 10-5, 5.5 × 10-5, 9.1 × 10-5 m/s in PAC adsorption and 2.0 × 10-5, 1.1 × 10-5, 9.0 × 10-6 m/s in TiO2 adsorption for a different MM concentration of 20, 50 and 70 mg/L, respectively. Photocatalysis kinetics was same with TiO2 of 0.2 g/L regardless of TiO2 amounts and the MM degradation kinetics was enhanced by TiO2 catalysis rather than only UV light degradation. Among the photocatalysis kinetics model with first-order, second-order and Langmuir-Hinshelwood (L-H) model, a second-order kinetic model was found to well present the experimental data of MM by TiO2 catalyst for the range of various TiO2 amounts and MM concentration studied. © 2007 Elsevier B.V. All rights reserved

Effect of flocculation as a pretreatment to photocatalysis in the removal of organic matter from wastewater

Effects of different flocculants (chloride-based salts and ferric and ferrous salts) and initial organic concentration of wastewater on flocculation-photocatalysis hybrid process were investigated. Titanium dioxide (TiO2) adsorption alone, flocculation alone, flocculation followed by TiO2 adsorption, photocatalysis alone, and flocculation followed by photocatalysis removed 60, 72, 80, 85, and 92% of dissolved organic matter (DOC), respectively. The effect of photo-Fenton reaction in removing organic matter was found to be marginal on the flocculation-photocatalysis hybrid system. The organic removal with the flocculation-photocatalysis hybrid system showed similar results for different flocculants such as chloride-based salts, ferric and ferrous salts and there is no comparative beneficial effect. Flocculation followed by photocatalysis removed up to 92% of organic matter. Different initial concentrations of organic matter were significantly reduced by flocculation to a low level before loading to the photocatalysis process. © 2007 Elsevier B.V. All rights reserved

Ubiquitous Graphene Electronics on Scotch Tape

We report a novel concept of graphene transistors on Scotch tape for use in ubiquitous electronic systems. Unlike common plastic substrates such as polyimide and polyethylene terephthalate, the Scotch tape substrate is easily attached onto various objects such as banknotes, curved surfaces, and human skin, which implies potential applications wherein electronics can be placed in any desired position. Furthermore, the soft Scotch tape serves as an attractive substrate for flexible/foldable electronics that can be significantly bent, or even crumpled. We found that the adhesive layer of the tape with a relatively low shear modulus relaxes the strain when subjected to bending. The capacitance of the gate dielectric made of oxidized aluminum oxide was 1.5 mu F cm(-2), so that a supply voltage of only 2.5 V was sufficient to operate the devices. As-fabricated graphene transistors on Scotch tape exhibited high electron mobility of 1326 (+/- 155) cm(2) V-1 s(-1); the transistors still showed high mobility of 1254 (+/- 478) cm(2) V-1 s(-1) even after they were crumpled.open1133Ysciescopu

Enhancement strategies for hydrogen production from wastewater: A review

© 2016 Bentham Science Publishers. This mini review focuses on the current developments in the field of dark fermentation technologies using wastewater as carbon and nutrient source in batch reactors. Besides, the major microbiota (pure, enriched mixed, co and mixed cultures) involved in the process have been emphasized. Additionally, problems associated with the lower production performances and the overcoming strategies applied to enhance the production rate (HPR) and yield (HY) bybio-augmentation, immobilization, enrichment technique and nano particles (NP) addition were also discussed. This mini review provides more insights about the recent developments in the dark fermentative hydrogen production (DHFP) process and their advantages in a brief manner. The perspective towards the development of sustainable society by using bioH2 technology is enlightened

Influences of operational parameters on phosphorus removal in batch and continuous electrocoagulation process performance

© 2017, Springer-Verlag GmbH Germany. Performance of an electrocoagulation (EC) process in batch and continuous operating modes was thoroughly investigated and evaluated for enhancing wastewater phosphorus removal under various operating conditions, individually or combined with initial phosphorus concentration, wastewater conductivity, current density, and electrolysis times. The results revealed excellent phosphorus removal (72.7–100%) for both processes within 3–6 min of electrolysis, with relatively low energy requirements, i.e., less than 0.5 kWh/m3 for treated wastewater. However, the removal efficiency of phosphorus in the continuous EC operation mode was better than that in batch mode within the scope of the study. Additionally, the rate and efficiency of phosphorus removal strongly depended on operational parameters, including wastewater conductivity, initial phosphorus concentration, current density, and electrolysis time. Based on experimental data, statistical model verification of the response surface methodology (RSM) (multiple factor optimization) was also established to provide further insights and accurately describe the interactive relationship between the process variables, thus optimizing the EC process performance. The EC process using iron electrodes is promising for improving wastewater phosphorus removal efficiency, and RSM can be a sustainable tool for predicting the performance of the EC process and explaining the influence of the process variables