Superposition of Stationary Wave Fields Via Atom Microscopy

We investigate one-dimensional position microscopy of a three-level atom moving through a stationary wave region under the condition of electromagnetically induced transparency.The precise position information of an atom is observed on the resonance absorption and dispersion distribution spectrum of a weak probe field.Single and multiple localization peaks are observed in specific directions of the corresponding wave numbers and phase of the standing wave fields.The strength of space-independent Rabi frequency reduces the position uncertainty in the localized peaks without disturbing the probability of the atom.In a hot atomic medium the localized probability of an atom is reduced which depends upon the temperature of that medium.Our results provide useful applications in the development of laser cooling,atom nanolithography and Bose-Einstein condensation.     

Application of Ritz functions in buckling analysis of embedded orthotropic circular and elliptical micro/nano-plates based on nonlocal elasticity theory

A continuum model based on the nonlocal theory of elasticity is developed for buckling analysis of embedded orthotropic circular and elliptical micro/nano-plates under uniform in-plane compression. The nanoplate is considered to be rested on two-parameter Winkler-Pasternak elastic foundation. The principle of virtual work is used to derive the governing vibration and stability equations. The weighted residual statements of the equations of motion are performed and the well-known Galerkin method is employed to obtain the nonlocal “Quadratic Functional” for embedded micro/nano-plates. The Ritz functions are taken to form an expression for transverse displacement which satisfies the kinematic boundary conditions. In this way, the entire nanoplate is considered as a single super-continuum element. Employing the Ritz functions eliminates the need for mesh generation and thus large number of degrees of freedom arising in discretization methods such as finite element (FE). The results show obvious dependency of critical buckling loads on the non-locality of the micro/nano elliptical plate, especially, at very small dimensions.     

4-Hydroxy-2-quinolones. 39. Structure of 6-bromo-4-hydroxy-1-isoamyl-2-oxo-3-quinolinecarboxylic acid

S-(–)-1-phenylethylamide of 6-bromo-4-hydroxy-1-isoamyl-2-oxo-3-quinolinecarboxylic acid was synthesized. X-ray diffraction investigation of this product was carried out to determine its absolute configuration.For communication 38, see ref. [1].National Pharmaceutical Academy of Ukraine, 310002 Kharkov, Ukraine Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 64–69, January, 2000.     

The Haj & #x00F3;s Property for 2-Groups

If G is a finite abelian group and k > 1 is an integer, we say that G has the Hajós k-property, if from each factorization G = A ₁ A ₂···A _k of G into direct product of subsets, it follows that at least one of the subsets A _i is periodic, in the sense that there exists x ∊ G − {e} such that xA _i = A _i . In this paper, we shall study 2-groups with respect to this property.     

Tetra­butyl­bis(N‐phthaloyl­glycinato)­distannoxane dimer

The crystal structure of the title compound, [Sn₄(C₄H₉)₈(C₁₀H₆NO₄)₄O₂], contains centrosymmetric dimers. It contains a central Sn₂O₂ core with the O atoms bonded to two di­butyl­bis(N‐phthaloyl­glycinato)­tin units. The Sn atoms of the core are six‐coordinate in a skew trapezoidal bipyramidal geometry, while the exocyclic Sn atoms are essentially five‐coordinate in a distorted trigonal geometry. The Sn—C distances lie in a narrow range of 2.120 (5)–2.138 (4) Å.     

Quantitation of Some Recently Introduced Antibacterial Drugs Using Sudan III as Chromogenic Reagent

 A simple, rapid, accurate and sensitive spectrophotometric method for the determination of norfloxacin (NRF), ofloxacin (OFL) and ciprofloxacin (CPF) is described. This method is based on the formation of an ion pair with sudan III in aqueous-acetone medium [40% (v/v) acetone]. The coloured products are measured at 567, 565 and 566 nm for NRF, OFL and CPF, respectively. The optimization of various experimental conditions is described. Beer’s law is obeyed in the range 0.4–12.0, 0.4–8.8 and 0.4–10.4  ;μg mL⁻¹ of NRF, OFL and CPF, respectively. For more accurate results, Ringbom optimum concentration ranges were 0.8–11.2, 0.6–8.5 and 0.8–10.0 μg mL⁻¹, respectively. The results obtained showed good recoveries of ±1.2, ±1.5 and ±1.7% with relative standard deviations of 0.67, 0.83 and 1.08% for NRF, OFL, and CPF, respectively. The molar absorptivity and Sandell sensitivity were also calculated. Applications of the proposed method to representative pharmaceutical formulations are successfully presented. Received April 30, 1999. Revision November 25, 1999.     

Integration of Phase Change Material in the Design of Solar Concentrator-Based Water Heating System

Indonesia has been blessed with excellent solar heat distribution, which can be used as renewable energy to heat water. Various technologies have been developed to utilize these inexhaustible thermodynamic resources, in the form of photons arrays, converted into concentrated heat for daily use, i.e., solar water heater. This renewable-based water heating system can provide significant energy efficiency, benefit the environment, and reduce energy use costs. This experimental study attempts to harvest the energy from the sun using a cylindrical through collector (CTC) type solar concentrator. The CTC was made of the solar reflective film (SRF) affixed to concentrator collector surfaces which was then mounted on an adjustable angle frame of the concentrator collector support. The heat generated from the concentrator was stored in water, and phase change material is embedded in the system to retain the heat longer. The research was carried out in Langsa City, Aceh, Indonesia. The results showed that water heaters using CTC systems could produce 16 L of hot water retained at 40–60 °C for four hours. With the addition of beeswax, the water temperature of the same capacity can be maintained at 40–60 °C for around 5 h. This technology demonstrated an excellent result that produces as much as 60 L of water per day, increasing solar thermal energy efficiency. This technology presented a great potential for replication or even for further development on an industrial scale.     

Selected Class of Enamides Bearing Nitro Functionality as Dual-Acting with Highly Selective Monoamine Oxidase-B and BACE1 Inhibitors

A small series of nitro group-bearing enamides was designed, synthesized (NEA1–NEA5), and evaluated for their inhibitory profiles of monoamine oxidases (MAOs) and β-site amyloid precursor protein cleaving enzyme 1 (β-secretase, BACE1). Compounds NEA3 and NEA1 exhibited a more potent MAO-B inhibition (IC₅₀ value = 0.0092 and 0.016 µM, respectively) than the standards (IC₅₀ value = 0.11 and 0.14 µM, respectively, for lazabemide and pargyline). Moreover, NEA3 and NEA1 showed greater selectivity index (SI) values toward MAO-B over MAO-A (SI of >1652.2 and >2500.0, respectively). The inhibition and kinetics studies suggested that NEA3 and NEA1 are reversible and competitive inhibitors with K_i values of 0.013 ± 0.005 and 0.0049 ± 0.0002 µM, respectively, for MAO-B. In addition, both NEA3 and NEA1 showed efficient BACE1 inhibitions with IC₅₀ values of 8.02 ± 0.13 and 8.21 ± 0.03 µM better than the standard quercetin value (13.40 ± 0.04 µM). The parallel artificial membrane permeability assay (PAMPA) method demonstrated that all the synthesized derivatives can cross the blood–brain barrier (BBB) successfully. Docking analyses were performed by employing an induced-fit docking approach in the GLIDE module of Schrodinger, and the results were in agreement with their in vitro inhibitory activities. The present study resulted in the discovery of potent dual inhibitors toward MAO-B and BACE1, and these lead compounds can be fruitfully explored for the generation of newer, clinically active agents for the treatment of neurodegenerative disorders.     

Free vibration analysis of general stepped circular plates with internal elastic ring support resting on Winkler foundation by green function method

Natural frequencies are important dynamic characteristics of a structure. Therefore, the exact solution pertaining to free vibration of stepped circular plate elastically restrained against rotation, translation, and internal elastic ring support resting on an arbitrary variable elastic foundation using Green Function is presented in this paper. Thus, an accurate and direct modeling technique is introduced for modeling stepped circular plate on an arbitrary variable elastic foundation with arbitrary boundary conditions and internal elastic ring support. The effect of the translational along with rotational support flexibilities, as well as, the elastic coefficient of Winkler foundation and other parameters are assessed. Finally, some numerical examples are shown in order to present the efficiency and simplicity of the Green Function in the new formulation.     

Upper bound analysis of wire flat rolling with experimental and FEM verifications

In this paper, an upper bound analysis is developed to calculate the rolling torque in the wire flat rolling process. Streamlines are defined parametrically in the deforming region and the formulation of the admissible velocity field are developed. The internal and frictional power terms are obtained from the upper bound solution. Through the analysis, the rolling torque is obtained. Furthermore, the effects of the roll speed, wire diameter, and reduction in height on the rolling torque are studied. In addition, the experimental and numerical investigations are performed to verify the proposed theoretical model. A very good agreement is obtained between the analytical results with those from the simulation and the experiment.