Separation and determination of ciprofloxacin in seawater,human blood plasma and tablet samples using molecularly imprinted polymer pipette‐tip solid phase extraction and its optimization by response surface methodology

By synthesizing a molecular imprinted polymer as an efficient adsorbent, ciprofloxacin was micro‐extracted from seawater, human blood plasma and tablet samples by pipette‐tip micro solid phase extraction and determined spectrophotometrically. Response surface methodology was applied with central composite design to build a model based on factors affecting on microextraction of ciprofloxacin; including volume of eluent solvent, number of extraction cycles, number of elution cycles, and pH of sample. Other factors that affect extraction efficiency, such as type of eluent solvent, volume of sample, type, and amount of salt were optimized with one‐variable‐at‐a‐time method. Under optimum extraction condition, pH of sample solution was 7.0, volume of eluent solvent (methanol) was 200 µL, volume of sample solution was 10 mL, and the number of extraction and elution cycles was five and seven, respectively, amount of Na₂SO₄ (as salt) and MIP (as sorbent) were optimized at 150 and 2 mg, respectively. The linear range of the suggested method under optimum extraction factors was 5–150 µg/L with a limit of detection of 1.50 µg/L for the analyte. Reproducibility of the method (as relative standard deviation) was better than 7%.     

A novel partial SOI LDMOSFET with a trench and buried P layer for breakdown voltage improvement

In this paper for the first time, a partial silicon-on-insulator (PSOI) lateral double-diffused metal-oxide-semiconductor-field-effect-transistor (LDMOSFET) is proposed with a novel trench which improves breakdown voltage. The introduced trench in the partial buried oxide enhances peak of the electric field and is positioned in the drain side of the drift region to maximize breakdown voltage. We demonstrate that the electric field is modified by producing two additional electric field peaks, which decrease the common peaks near the drain and gate junctions in the trench-partial-silicon-on-insulator (T-PSOI) structure. Hence, a more uniform electric field is obtained. Two dimensional (2D) simulations show that the breakdown voltage of T-PSOI is nearly 64% higher in comparison with partial silicon on insulator (PSOI) structure and alleviate self heating effect approximately 9% and 15% in comparison with its conventional PSOI (C-PSOI) and conventional SOI (C-SOI) counterparts respectively. In addition the current of the T-PSOI, C-PSOI, conventional SOI (C-SOI), and fully depleted conventional SOI (FC-SOI) structures are 90, 82, 74, and 44 μA, respectively for a drain–source voltage V_DS = 30 V and gate–source voltage V_GS = 10 V.     

Ab initio study of the effect of thickness and epitaxial strain on the magnetic structure of NiMn freestanding films

The magnetic properties of tetragonal structure of stoichiometric NiMn alloy is investigated using density functional theory within the local spin density approximation. The system studied here, is a free standing film. The effect of thickness and epitaxial strain on the magnetic and structural properties is examined. It is found that while the magnetic moments of Mn surface atoms vary depending on the number of layers being odd (3.60 ${\mathrm{\mu }}_{\mathrm{B}}$) or even (3.55 ${\mathrm{\mu }}_{\mathrm{B}}$) the magnitude of the magnetic moment for surface Ni atoms is constant (0.11 ${\mathrm{\mu }}_{\mathrm{B}}$). By applying epitaxial strain on the slabs, it was observed, for the first time, that the magnetic phase of NiMn films changes from “A-type-like” ferrimagnetic for compressive strains to “G-type-like” ferrimagnetic for tensile strains.     

Estimation of mechanical properties of LDPE/LLDPE/SEBS nanocomposite reinforced with calcium carbonate nanoparticles by Ch mathematical model

Journal of Thermal Analysis and Calorimetry - Doing experiments in order to determine mechanical properties of nanocomposites costs a lot. Therefore, finding the ways by which the properties of the...     

The non-abelian simple groupsG, ¦G¦ <106, minimalC-generator pairs, symmetric presentations

In this paper we describe the results of computations to find symmetric presentations based on minimal conjugate generating pairs for the 32 non-abelian simple groups of order less than one million.     

Experimental and Theoretical Study of Enhanced Photocatalytic Activity of Mg‐Doped ZnO NPs and ZnO/rGO Nanocomposites

A systematic experimental and theoretical study of the origin of the enhanced photocatalytic performance of Mg‐doped ZnO nanoparticles (NPs) and Mg‐doped ZnO/reduced graphene oxide (rGO) nanocomposites has been performed. In addition to Mg, Cd was chosen as a doping material for the bandgap engineering of ZnO NPs, and its effects were compared with that of Mg in the photocatalytic performance of ZnO nanostructures. The experimental results revealed that Mg, as a doping material, recognizably ameliorates the photocatalytic performance of ZnO NPs and ZnO/graphene nanocomposites. Transmission electron microscopy (TEM) images showed that the Mg‐doped and Cd‐doped ZnO NPs had the same size. The optical properties of the samples indicated that Cd narrowed the bandgap, whereas Mg widened the bandgap of the ZnO NPs and the oxygen vacancy concentration was similar for both samples. Based on the experimental results, the narrowing of the bandgap, the particle size, and the oxygen vacancy did not enhance the photocatalytic performance. However, Brunauer–Emmett–Teller (BET) and Barret–Joyner–Halenda (BJH) models showed that Mg caused increased textural properties of the samples, whereas rGO played an opposite role. A theoretical study, conducted by using DFT methods, showed that the improvement in the photocatalytic performance of Mg‐doped ZnO NPs was due to a higher electron transfer from the Mg‐doped ZnO NPs to the dye molecules compared with pristine ZnO and Cd‐doped ZnO NPs. Moreover, according to the experimental results, along with Mg, graphene also played an important role in the photocatalytic performance of ZnO.     

Ag‐Catalyzed Trifluoromethylative Ring Expansion of Isatins and Isatin Ketimines with Trifluorodiazoethane

A general method for the construction of trifluoromethylated 2‐quinolinones has been established herein by using a trifluoromethylative ring expansion of isatin with trifluorodiazoethane. The strategy provides a platform for the rapid synthesis of a wide range of substituted 3‐hydroxy‐4‐trifluoromethyl‐2‐quinolinones. This operationally simple and robust Ag‐catalyzed protocol successfully transforms isatin ketimines to 3‐amino‐4‐trifluoromethylquinolinones in excellent yields. The utility of this novel method is further illustrated by the conversion of the products into various synthetically and medicinally relevant molecules.     

Sensitivity analysis of inefficient units in data envelopment analysis

One important issue in DEA which has been studied by many DEA researchers is the sensitivity of the results of an analysis to perturbations in the data.This paper develops a procedure for performing a sensitivity analysis of the inefficient decision making units (DMUs). The procedure yields an exact “Necessary Change Region” in which the efficiency score of a specific inefficient DMU changes to a defined efficiency score.In what follows, we identify a new frontier, and prove the efficiency score of each arbitrary unit on it which is defined as the efficiency score.     

Efficient presentations for certain simple groups

In this paper we give 2-generator 3-relation presentations for the simple groups PSU(3,5) of order 126000 and the Mathieu group M_22Zof order 443520. We also give a 2-generator 2-relation presentation for the Janko group J₁of order 175560. This proves that these three simple groups are efficient.