Preparation and Characterization of Acetic Acid-Functionalized Fe3O4@SiO2 Nanoparticles as an Efficient Nanocatalyst for the Synthesis of Nitrones in Water

Silicon - Magnetic materials grafted with acetic acid (Fe3O4@SiO2COOH MNPs) were successfully prepared from the incorporation of bromoacetic acid as a functional group on the surface of magnetite...     

Antioxidant Activity,Reaction Mechanisms,and Kinetics of Matricaria recutita Extract in Commercial Blended Oil Oxidation

Antioxidant activity, reaction mechanisms, and kinetics of Matricaria recutita crude extract (CE; total phenolics: 41 ± 2.5 mg/g, total flavonoids: 26 ± 1.4 mg/g, IC₅₀: 82.3 ± 2.8 µg/mL and reducing power: 10.45 ± 0.56 mmol Fe²⁺/mass) in comparison to tert-Butylhydroquinone during oxidation of blended vegetable oil (sunflower, soybean, and palm oil) at 120, 130, and 140°C were studied. Good correlations existed between the Rancimat oil stability index and stability indices (induction period) calculated from peroxide value, conjugated diene value, and anisidine value with no significant differences in kinetic parameters calculated from them. The temperature acceleration (Q₁₀), activation energy (E_a), frequency factor (A), enthalpy (ΔH⁺⁺), entropy (ΔS⁺⁺), and free energy of activation (ΔG⁺⁺) for oils containing crude extract were lower than for oils containing tert-Butylhydroquinone (0.0025, 0.005, 0.01, and 0.02%). Values were independent of crude extract or tert-Butylhydroquinone concentration. For crude extract and tert-Butylhydroquinone, E_a and A were well correlated with ΔH⁺⁺ and ΔS⁺⁺ values, respectively, but correlation between E_a and Q₁₀ for crude extract compared to tert-Butylhydroquinone was poor. Furthermore, the rate of Monounsaturated:Polyunsaturated fatty acids formation did not differ significantly between crude extract and tert-Butylhydroquinone, but concentrations of them did affect Monounsaturated:Polyunsaturated ratio. Based on the results obtained, crude extract decreased the rate of the oxidation reaction due to the decrease in the concentration of the activated complex and reduction in the rate at which the activated complex dissociated into oxidation products.     

Sex and age distribution in transport-related injuries in Tehran

Intercountry or regional differences in patterns of injury by the road user type have significant implication for prevention policies. In order to have an estimate from the existing conditions of transport-related injuries (TRIs) and especially to evaluate sex and age distribution of traffic accident victims, we analyzed information of 8426 hospitalized trauma patients during 13 months of data gathering process. Forty-five percent of the injuries were related to car accidents and men/women ratio in these patients was 4.2/1. The highest men/women ratio was (16/1) for motorcyclists, while the lowest ratio (1/1), was for rear seat car passengers. Mean (+/-S.D.) age of the patients was 31 (+/-18), and men were nearly 2 years younger than women (33 versus 31). Sixty-seven percent of the females' and 44% of the males' injuries were related to pedestrian crashes. Motorcycle-related injuries in men and car passenger related injuries in women were the second most common type of crash (42 and 22%, respectively). The use of protective devices in our population was worrisome. In only 6% of the male motorcyclists helmet use was reported, and 3% of the male car occupants had used seatbelts at the time of the accident. The condition in the female population was much worse and no use of the protective devices was reported in this group of the patients. Crude mortality rate in men was nearly two times that of women (6.2% versus 3.8%). After adjustment for age, injury severity score (ISS) and category of the road users, men and women had similar mortality rate.     

Some models for understanding the cooperation between the supplier and the buyer

This paper presents some stochastic models of cooperation between the supplier and the buyer. We first recall some of the results that pertain to the case where the buyer and the supplier formulate their inventory policies independently and sequentially. Next, we analyse the case where the buyer and the supplier jointly determine the optimal order quantities. Our analysis shows that only the supplier benefits from such cooperation. In order to motivate the buyer to cooperate, we consider some cooperative strategies. These include the analysis of the impact of (1) price changes, (2) discount policies and (3) partial deliveries. The importance of coordination is brought out from the analysis.     

Fault detection and approximation for a class of linear impulsive systems using sliding‐mode observer

The objective of this paper is to develop a method for fault detection and approximation of linear impulsive systems exposed to actuator faults. Utilizing proposed sliding mode observer, states of the impulsive system are estimated. It is proved that estimation error dynamical system is asymptotically stable between jumps. In addition, an upper bound of the state estimation errors at jump instants has been derived explicitly. State estimations are used to reconstruct the fault signal. Furthermore, an upper bound of the fault estimation errors is obtained. Proficiency of the proposed method is evaluated under different fault scenarios using numerical simulations. Copyright © 2015 John Wiley & Sons, Ltd.     

Ultra-thin decoupled plasma nitridation (DPN) oxynitride gate dielectric for 80-nm advanced technology

Balancing gate leakage reduction, device performance, and gate dielectric reliability is a major challenge for oxynitride used as a gate dielectric for advanced technology. As compared to RTONO oxynitride, pMOSFET threshold voltage shift and transconductance degradation have been problematic for devices using remote plasma nitridation (RPN) or decoupled plasma nitridation (DPN) process due to non-optimal nitrogen profile in the film. In this paper, we report that the nitrogen profile of DPN gate dielectric can be engineered primarily by tuning the plasma pressure after optimizing other DPN process parameters to solve these problems. An EOT of 15 /spl Aring/ (23-/spl Aring/ NMOS CETinv) DPN oxynitride is demonstrated to have an acceptable pMOS Vt, comparable transconductance, significantly (/spl sim/30/spl times/) longer pMOS time-to-breakdown reliability for packaged devices, and 5/spl times/ gate leakage reduction relative to a high quality RTONO used in industry. The high quality ultrathin DPN film is fabricated in a commercially available system, which is compatible with standard CMOS processing technology. These encouraging results make high-pressure DPN oxynitride an attractive gate dielectric candidate for 80-nm advanced technology and beyond.     

A class of multistep methods based on a super-future points technique for solving IVPs

In this article, the details of new methods based on a super-future points technique, for improving stability regions compared with those of the extended BDF (EBDF) and modified EBDF (MEBDF), have been presented, for solving initial value problems (IVPs). Numerical results related to five test problems show that our new methods have good performance in saving CPU time compared with the corresponding MEBDF method.     

Preparation of hydroxyapatite-calcium ferrite composite for application in loading and sustainable release of amoxicillin: Optimization and modeling of the process by response surface methodology and artificial neural network

In this research, a merit carrier consisting of hydroxyapatite and calcium ferrite (HAp-CaFe₂O₄) was prepared via a convenient procedure and characterized using a series of techniques, including XRD, FE-SEM, TEM, EDS mapping, BET/BJH, VSM, and TGA. The loading of Amoxicillin (AMX) onto HAp-CaFe₂O₄ was optimized and modeled by two powerful approaches, namely response surface methodology (RSM) and artificial neural network (ANN). RSM-optimized results demonstrated that the maximum drug loading efficiency was 91.76% at a carrier dosage of 1.2 g, a drug concentration of 30 mg L^?1, and a pH of 6.5 within a stipulated time of 60 min. ANN modeling revealed that the pH of the solution had a dramatic effect with a 35% impact on the drug loading process. The downloading of AMX by HAp-CaFe₂O₄ was consistent with pseudo-2nd order and intra-particle diffusion kinetics models as well as the Temkin isotherm model, implying the chemisorption of the drug molecules on the carrier. The AMX release was evaluated at different pHs, and it was revealed that the sustained and prolonged drug evacuation occurred in the neutral medium as compared to acidic and basic media. The conformity of the drug release kinetics to the Korsmeyer-Peppas model indicated that the Fickian diffusion dominated the AMX release. The MTT assay showed the biocompatibility and safety of HAp-CaFe₂O₄ toward A549 cell lines.In summary, as-prepared HAp-CaFe₂O₄ can be regarded as a biocompatible and stimuli-responsive carrier for controlled and targeted drug delivery systems.     

Organic photovoltaic cells based on self-assembly fabrication of vertically aligned CuPc nanorods upon fullerene particles

We demonstrate the self-assembled growth of vertically aligned Copper Phthalocyanine (CuPc) nanorods which are directly evaporated on fullerene (C₆₀) islands. UV–Vis spectroscopy of CuPc nanorods, compared to planar CuPc, shows an improvement in light absorption within the visible range. Moreover, scanning electron microscopy (SEM) demonstrates the presence of well-arranged vertically aligned CuPc nanorods suggesting an increase in the donor–acceptor interface. X-ray diffraction (XRD) reveals the crystalline nature of these nanorods. Different organic photovoltaic cells have been fabricated using these nanorods. High current density achieved with the cell arrangement of CuPc/CuPc-nanorods/C₆₀ in comparison to regular planar CuPc/C₆₀ device. The power conversion efficiency is also doubled compared to the planar one.     

Synthesis of fluorescent ABA triblock copolymer via click reaction

A hyperbranched–linear–hyperbranched (ABA) triblock copolymer containing poly(ethylene glycol) (PEG) as linear block and polyglycerol (hbPG) as hyperbranched blocks has been synthesized through a copper‐catalysed click reaction. In order to synthesize the hyperbranched block, propargyl alcohol‐initiated ring‐opening multibranching polymerization of glycidol was used to prepare hbPG with the propargyl segment in the focal point (CH?C? hbPG). Separately, PEG was functionalized at both ends using cyanuric chloride, and then the chloride groups of cyanuric chloride were substituted by azide groups. Finally, the azide‐functionalized PEG was conjugated to CH?C? hbPG via a click reaction. Substitution of the chlorine atoms of cyanuric chloride under different conditions together with click chemistry allows the synthesis of a variety of polymeric architectures. In the last step, fluorescein was attached to the block copolymer as a fluorescent probe in order to study the cell internalization of this copolymer. This type of triblock copolymer is a promising future nanomaterial for simultaneous drug delivery and cell imaging. © 2016 Society of Chemical Industry