Synthesis of aromatic amine phosphonato ester derivatives from the stereoselective reaction between triphenyl phosphite and dimethyl acetylenedicarboxylate in the presence of derivatives of aromatic amines

Aromatic amine phosphonato esters 4a–d were obtained in excellent yields from the 1:1:1 addition reaction between triphenyl phosphite and dimethyl acetylenedicarboxylate in the presence of NH‐aromatic amines such as 2‐aminobenzophenone, 2‐aminoacetophenon, methyl‐2‐aminobenzoate, and 2‐aminobenzonitrile. In the recent works, the assignments of the configuration of 4a–d corresponding to the three‐bond carbon‐phosphorus coupling, ³Jpc, was determined on the basis of coupling constants by the Karplus equation as 2R *, 3R *or 2S *, 3S * while they were 2R *, 3S * or 2S *, 3R * in our previous works in the presence of same solvent. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:240–245, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20541     

Novel attributes in the performance and scaling effects of carbon nanotube field-effect transistors with halo doping

In this paper, we performed a comprehensive scaling study of a carbon nanotube field-effect transistor (CNTFET) with halo doping (HD) using self-consistent and atomistic scale simulations. Our simulation results demonstrate that drain induced barrier lowering (DIBL) diminishes in the HD-CNTFET due to a step in the potential of the CNT at the interface of p-doped and undoped regions in the channel. Also, the hot carrier effect minimizes with reduction of the peak of the electric field at the drain side of the HD-CNTFET. Moreover, the features of the HD-CNTFET can be controlled by the length and concentration engineering of the HD region. Leakage current, on–off current ratio and subthreshold swing improve with an increase of the length and concentration of the HD region, due to the increment of the threshold voltage and the barrier height of the p–n junction near the source. Therefore, this work can provide an incentive for further experimental exploration.     

Lattice Boltzmann study of multi-walled carbon nanotube (MWCNT)-Fe3O4/water hybrid nanofluids natural convection heat transfer in a Π-shaped cavity equipped by hot obstacle

In the present paper, the effect of nanofluid and the hot obstacle in a Π-shaped cavity is investigated. Lattice Boltzmann method is used to simulate the fluid flow and heat transfer. The effects of the parameters such as the nanoparticle solid volume fraction, the Rayleigh number, aspect ratio of cavity and hot obstacle position on the flow pattern and heat transfer parameters are studied. The numerical results are compared with previous results for validation, and a good agreement obtained. It is found that the average Nusselt number is increased by increasing the nanoparticle solid volume fraction, the Rayleigh number and the aspect ratio of cavity. Moreover, the effect of Rayleigh number on the average Nusselt number at high Rayleigh numbers (10⁵–10⁶) is more pronounced than that at low Rayleigh numbers (10³–10⁴) due to the different heat transfer mechanisms. The position of the hot obstacle affects the heat transfer significantly. When the hot obstacle is located on the center, the heat transfer is more effective.

     

A green one-pot synthesis of 3(5)-substituted 1,2,4-triazol-5(3)-amines as potential antimicrobial agents

Journal of the Iranian Chemical Society - An efficient procedure was proposed for the synthesis of 3(5)-substituted 1,2,4-triazol-5(3)-amines via a one-pot reaction of thiourea, dimethyl sulfate...     

Effective Designs of Reversible Vedic Multiplier

Power dissipation problem is one of the most challenging problems in designing conventional electronic circuits. One of the best approaches to overcome this problem is to design reversible circuits. Nowadays, reversible logic is considered as a new field of study that has various applications such as optical information processing, design of low power CMOS circuits, quantum computing, DNA computations, bioinformatics and nanotechnology. Due to the vulnerability of the digital circuits to different environmental factors, the design of circuits with error-detection capability is considered a necessity. Parity preserving technique is known as one of the most famous methods for providing error-detection ability. Multiplication operation is considered as one of the most important operations in computing systems, which can play a significant role in increasing the efficiency of such systems. In this paper, two efficient 4-bit reversible multipliers are proposed using the Vedic technique. The Vedic technique is able to increase the speed of multiplication operation by producing partial products and their sums simultaneously in a parallel manner. The first architecture lacks the parity preserving potential, while the second architecture has the ability parity preserving. Since a 4-bit Vedic multiplier includes 2-bit Vedic multipliers and 4-bit ripple carry adders (RCA), so in the first design, TG, PG and FG gates have been used to design an efficient 2-bit reversible Vedic multiplier, as well as PG gate and HNG block have been applied as a half-adder (HA) and full-adder (FA) in the 4-bit RCAs. Also, in the second design, 2-bit parity preserving reversible Vedic multiplier has been designed using FRG, DFG, ZCG and PPTG gates as well as ZCG and ZPLG blocks have been utilized as HA and FA in the 4-bit RCAs. Proposed designs are compared in terms of evaluation criteria of circuits such as gate count (GC), number of constant inputs (CI), number of garbage outputs (GO), quantum cost (QC), and hardware complexity. The results of the comparisons indicate that the proposed designs are more efficient compared to available counterparts.

     

Formation of a percolating cluster in films prepared by cathodic electrodeposition of a mixture of lower and higher molecular weight epoxy-amine adducts

The electrodeposition behavior of blends of primary dispersions of a lower and a higher molecular weight epoxy-amine adduct has been investigated. The throwing power of the above-mentioned blends showed a voltage-dependent critical composition at which the throwing power dropped to a much lower value. This was assigned to the formation of an infinite conducting cluster, the extension of which is dependent on the rate of the electrocoagulation process at the cathode boundary. The random resistor network approach of Stauffer (RRNS) and the random resistor network approach of Miller and Abrahams (RRNMA) were applied to the experimental data with high correlations (r2=0.9314 and 0.9699). The percolating cluster formed within the film, however, gave a critical exponent of conductivity equal to 1.1028, much less than expected from a classical three-dimensional lattice (i.e., 1.5-2.0). This discrepancy was explained in terms of the changed behavior of the film resulting from the bubbles formed near the cathode and its effect on the infinite conducting cluster.     

Détermination Directe de la Stéréochimie de l'Addition de Carbènes aux Oléfines Bicycliques par RMN du Carbone-13

The ¹³C chemical shift data of some tricyclic derivatives prepared by carbene addition to bicyclo-alkenes are presented and compared with the shifts observed in the parent olefins. The shielding induced at the C-7 atom can be used to determine the stereochemistry of the carbene addition.     

Folate-Targeted Curcumin-Loaded Niosomes for Site-Specific Delivery in Breast Cancer Treatment: In Silico and In Vitro Study

As the most common cancer in women, efforts have been made to develop novel nanomedicine-based therapeutics for breast cancer. In the present study, the in silico curcumin (Cur) properties were investigated, and we found some important drawbacks of Cur. To enhance cancer therapeutics of Cur, three different nonionic surfactants (span 20, 60, and 80) were used to prepare various Cur-loaded niosomes (Nio-Cur). Then, fabricated Nio-Cur were decorated with folic acid (FA) and polyethylene glycol (PEG) for breast cancer suppression. For PEG-FA@Nio-Cur, the gene expression levels of Bax and p53 were higher compared to free drug and Nio-Cur. With PEG-FA-decorated Nio-Cur, levels of Bcl2 were lower than the free drug and Nio-Cur. When MCF7 and 4T1 cell uptake tests of PEG-FA@Nio-Cur and Nio-Cur were investigated, the results showed that the PEG-FA-modified niosomes exhibited the most preponderant endocytosis. In vitro experiments demonstrate that PEG-FA@Nio-Cur is a promising strategy for the delivery of Cur in breast cancer therapy. Breast cancer cells absorbed the prepared nanoformulations and exhibited sustained drug release characteristics.     

8-Hydroxyquinoline Functionalized Graphene Oxide: an Efficient Fluorescent Nanosensor for Zn<Superscript>2+</Superscript> in Aqueous Media

A nanosensor, based on 8-hydroxyquinoline functionalized graphene oxide, was developed for the fluorescence detection of Zn²⁺. It showed high selectivity and sensitivity for Zn²⁺ion in aqueous solution over other metal ions such as Li⁺, Na⁺, Ca²⁺, Mg²⁺, Al³⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Pb²⁺, Fe²⁺, Fe³⁺and Cr³⁺. Due to the linearity of the emission intensity toward Zn²⁺ concentration, fluorescent technique could be used for the detection of Zn²⁺ ion even at very low concentrations.