Quantitative analysis of morphine and noscapine using corona discharge ion mobility spectrometry with ammonia reagent gas

Morphine and noscapine were determined using corona discharge ion mobility spectrometry. The detection limits were 5.6 × 10⁻¹¹ and 6.7 × 10⁻¹¹ g for morphine and noscapine, respectively. The linear dynamic ranges of the calibration plots for the compounds were about three orders of magnitude. The method has also been successfully applied for simultaneous determination of the compounds using the standard addition method.     

Developing an electro-thermal model to determine heat generation and thermal properties in a lithium-ion battery

Journal of Thermal Analysis and Calorimetry - Lithium-ion batteries should continuously be operated at the optimum temperature range $$left( {15 sim 40 ,^circ C} right)$$ for the best...     

The influence of La2O3 and TiO2 on NiO/MgO/α-Al2O3

Summary The effect of La₂O₃ and TiO₂ on product selectivity, methane conversion and coke formation over NiO/MgO/ α -Al₂O₃ catalyst were studied in a simultaneous steam and CO₂ reforming of methane to syngas. La₂O₃ and TiO₂ were added to the catalyst via incipient wetness impregnation and bulk precipitation techniques and catalyst activity was tested in a fixed bed quartz reactor. Results reveal that although the addition of these oxides has no effect on the product selectivity and methane conversion, but can reduce coke formation on the surface of the catalysts as it can enhance the mobility of lattice oxygen anions. The results further show that the catalysts prepared by bulk precipitation technique decrease the coke formation more effectively.     

Lattice Boltzmann simulation of particles agglomeration and rheology in a particulate flow

The dynamics and rheology of particles in a Newtonian fluid subjected to shear are simulated using Lattice Boltzmann Method. A computationally-efficient Smoothed Profile Method is used to resolve fluid-solid interactions, and the Lennard-Jones inter-particle potential is implemented to account for inter-particle forces. The use of a bi-periodic computational domain with Lees-Edward boundary conditions allows simulation for systems consisting of a large number of particles under shear. The method is validated for single and dual particle problems and an analysis is performed for multi-particle problems under a range of shear rates and particle fractions. The introduction of particle-particle interactions, which are physically important in many engineering processes, is found to have a considerable impact on the dynamics, agglomeration and rheology. The total stress exhibits high unsteadiness primarily due to the solid component contribution, at higher particle fractions. The simulations underscore the complex interplay between shear, interparticle forces and agglomeration and the complex dependencies of the rheological properties.     

Ionic behavior modification of cation exchange ED membranes by using CMC-co-Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles for heavy metals removal from water

A new mixed matrix polyvinyl chloride-based heterogeneous cation exchange membrane was prepared by incorporation of carboxy methyl cellulose-co-Fe₃O₄ nanoparticles through solution casting technique. The effect of simultaneous using of carboxy methyl cellulose and iron oxide nanoparticles in the casting solution on the physicochemical properties of membranes was studied. SOM images showed uniform particles distribution and uniform surfaces for the membranes relatively. The SEM images exhibited regular direction/spatial orientation for the CMC-co-Fe₃O₄ nanoparticles in the membrane matrix. XRD patterns showed that membrane heterogeneity was enhanced by using of Fe₃O₄ nanoparticles. Membrane ion exchange capacity, membrane surface hydrophilicity, membrane potential, surface charge density, transport number, selectivity, and ionic flux were increased by using CMC/Fe₃O₄ nanoparticles in membrane matrix. Results showed that membrane areal electrical resistance was declined up to 3.8 Ω cm² by utilizing CMC/Fe₃O₄ nanoparticles in the casting solution. Also PVC/CMC-co-Fe₃O₄ membrane showed higher transport number, selectivity, flux, and electrical conductivity compared to PVC/CMC membrane and unmodified ones. Electrodialysis experiment in laboratory scale showed higher dialytic rate in lead ions removal for PVC/CMC-co-Fe₃O₄ nanoparticle-mixed matrix ion exchange membrane compared to PVC/CMC membrane and pristine one.     

Electronic and Magnetic Properties of Linear and Dimerized Titanium Nanochains Under Compressive and Tensile Strain

The magnetic and electronic properties of both linear and dimerized nanochains of titanium at different atomic distances are calculated within density functional theory with the generalized gradient approximation. Titanium which is a nonmagnetic in its bulk form is shown to become magnetic in its nanochain structure. Also, a close relationship is found between magnetic state and geometry of chain structure and the dependence of electronic properties on the atomic structures of chains is revealed. It is found that, for dimerized nanochains from equilibrium constant, compressive strain leads to a reduction in magnetism. Moreover, characteristics of the systems near the Fermi level are investigated and the charge densities of both nanostructures are studied in the ferromagnetic order. The results show that metallic bonding is mainly responsible for the linear structure; however, for the dimerized structure, the bonding is more directional, i.e. has a more covalent character. With increasing tension along the axis of the nanostructures, a change in the types of bonding is found.     

Polarity‐based fractionation in proteomics: hydrophilic interaction vs reversed‐phase liquid chromatography

During recent decades, hydrophilic interaction liquid chromatography (HILIC) ahs been introduced to fractionate or purify especially polar solutes such as peptides and proteins while reversed‐phase liquid chromatography (RPLC) is also a common strategy. RPLC is also a common dimension in multidimensional chromatography. In this study, the potential of HILIC vs RPLC chromatography was compared for proteome mapping of human peripheral blood mononuclear cell extract. In HILIC a silica‐based stationary phase and for RPLC a C₁₈ column were applied. Then separated proteins were eluted to an ion trap mass spectrometry system. Our results showed that the HILIC leads to more proteins being identified in comparison to RPLC. Among the total 181 identified proteins, 56 and 38 proteins were fractionated specifically by HILIC and RPLC, respectively. In order to demonstrate this, the physicochemical properties of identified proteins such as polarity and hydrophobicity were considered. This analysis indicated that polarity may play a major role in the HILIC separation of proteins vs RPLC. Using gene ontology enrichment analysis, it was also observed that differences in physicochemical properties conform to the cellular compartment and biological features. Finally, this study highlighted the potential of HILIC and the great orthogonality of RPLC in gel‐free proteomic studies. Copyright © 2015 John Wiley & Sons, Ltd.     

Finite-element simulation of ultrasound brain surgery: effects of frequency, focal pressure, and scanning path in bone-heating reduction

In this paper, the finite-element method (FEM) simulation of ultrasound brain surgery is presented. The overheating problem of the post-target bone, which is one of the limiting factors for a successful ultrasound brain surgery, is considered. In order to decrease bone heating, precise choices of frequency, focal pressure, and scanning path are needed. The effect of variations in the mentioned scanning parameters is studied by means of the FEM. The resulting pressure and temperature distributions of a transdural ultrasound brain surgery are simulated by employing the FEM for solving the Helmholtz and bioheat equations in the context of a two-dimensional MRI-based brain model. Our results show that for a suitable value of the frequency, an increase in focal pressure leads to a decrease in the required duration of the treatment and is associated with less heating of the surrounding normal tissue. In addition, it is shown that at a threshold focal pressure, the target temperature reaches toxic levels whereas the temperature rise in the bone is minimal. Wave reflections from sinus cavities, which result in constructive interference with the incoming waves, are one of the reasons for overheating of the bone and can be avoided by choosing a suitable scanning path.      

Determination of desipramine in biological samples using liquid–liquid–liquid microextraction combined with in‐syringe derivatization,gas chromatography,and nitrogen/phosphorus detection

A method was established for the determination of desipramine in biological samples using liquid–liquid–liquid microextraction followed by in‐syringe derivatization and gas chromatography–nitrogen phosphorus detection. The extraction method was based on the use of two immiscible organic solvents. n‐Dodecane was impregnated in the pores of the hollow fiber and methanol was placed inside the lumen of the fiber as the acceptor phase. Acetic anhydride was used as the reagent for the derivatization of the analyte inside the syringe barrel. Parameters that affect the extraction efficiency (composition of donor and acceptor phase, ionic strength, sample temperature, and extraction time) as well as derivatization efficiency (amount of acetic anhydride and reaction time and temperature) were investigated. The limit of detection was 0.02 μg/L with intra and interday RSDs of 2.6 and 7.7%, respectively. The linearity of the method was in the range of 0.2–20 μg/L (r² = 0.9986). The method was successfully applied to determine desipramine in human plasma and urine.