2‐Aminopyridines as an α‐Bromination Shuttle in a Transition Metal‐Free One‐Pot Synthesis of Imidazo[1,2‐a]pyridines

A wide range of imidazo[1,2‐a]pyridines are accessible from cheap and readily available 2‐aminopyridines and 1,3‐dicarbonyl compounds using a unique CBrCl₃/2‐aminopyridine system for bromination at the α‐carbon. 2‐Aminopyridine is not only the substrate but also acts as a bromination shuttle, transferring the bromine atom from CBrCl₃ to the α‐carbon of the 1,3‐dicarbonyl. The reaction mechanism involves a series of reversible steps, including an addition reaction with cyclic transition state, to form a bromo‐hemiaminal intermediate. Isolated yields of up to 97% were obtained under mild conditions and at short reaction times in this transition metal‐free, one‐pot synthesis.

     

Aperiodic Fourier modal method in contrast-field formulation for simulation of scattering from finite structures

This paper extends the area of application of the Fourier modal method (FMM) from periodic structures to aperiodic ones, in particular for plane-wave illumination at arbitrary angles. This is achieved by placing perfectly matched layers at the lateral sides of the computational domain and reformulating the governing equations in terms of a contrast field that does not contain the incoming field. As a result of the reformulation, the homogeneous system of second-order ordinary differential equations from the original FMM becomes non-homogeneous. Its solution is derived analytically and used in the established FMM framework. The technique is demonstrated on a simple problem of planar scattering of TE-polarized light by a single rectangular line.     

Evaluating process in child and family interventions: Aggression prevention as an example.

This article reports on 2 studies designed to develop and validate a set of measures for use in evaluating processes of child and family interventions. In Study 1 responses from 187 families attending an outpatient clinic for child behavior problems were factor analyzed to identify scales, consistent across sources: Alliance (Satisfactory Relationship with Interventionist and Program Satisfaction), Parenting Skill Attainment, Child Cooperation During Session, Child Prosocial Behavior, and Child Aggressive Behavior. Study 2 focused on patterns of scale scores among 78 families taking part in a 22-week preventive intervention designed to affect family relationships, parenting, and child antisocial and prosocial behaviors. The factor structure identified in Study 1 was replicated. Scale construct validity was demonstrated through across-source convergence, sensitivity to intervention change, and ability to discriminate individual differences. Path analysis validated the scales' utility in explaining key aspects of the intervention process. Implications for evaluating processes in family interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sir3p domains involved in the initiation of telomeric silencing in Saccharomyces cerevisiae

Previous studies from our laboratory have demonstrated that tethering of Sir3p at the subtelomeric/telomeric junction restores silencing in strains containing Rap1-17p, a mutant protein unable to recruit Sir3p. This tethered silencing assay serves as a model system for the early events that follow recruitment of silencing factors, a process we term initiation. A series of LexA fusion proteins in-frame with various Sir3p fragments were constructed and tested for their ability to support tethered silencing. Interestingly, a region comprising only the C-terminal 144 amino acids, termed the C-terminal domain (CTD), is both necessary and sufficient for restoration of silencing. Curiously, the LexA-Sir3(N205) mutant protein overcomes the requirement for the CTD, possibly by unmasking a cryptic initiation site. A second domain spanning amino acids 481-835, termed the nonessential for initiation domain (NID), is dispensable for the Sir3p function in initiation, but is required for the recruitment of the Sir4p C terminus. In addition, in the absence of the N-terminal 481 amino acids, the NID negatively influences CTD activity. This suggests the presence of a third region, consisting of the N-terminal half (1-481) of Sir3p, termed the positive regulatory domain (PRD), which is required to initiate silencing in the presence of the NID. These data suggest that the CTD "active" site is under both positive and negative control mediated by multiple Sir3p domains.     

Inclined magnetized and energy transportation aspect of infinite shear rate viscosity model of Carreau nanofluid with multiple features over wedge geometry

Heat transference in fluid mechanism has a deep influence in real-life applications like hot-mix paving, recovery of energy, concrete heating, heat spacing, refineries, distillation, autoclaves, reactors, air conditioning, and so forth. In this attempt, findings related to energy exchange with features of infinite shear rate viscosity model of Carreau nanofluid by placing inclined magnetic dipole over the wedge are made. The main role in the transportation of heat is exercised by incorporating facts of r adiation, nonuniform heat sink source, Brownian motion, thermophoresis, and chemical reaction. The mathematical system of the infinite shear rate viscosity model of Carreau nanofluid gives a system of partial differential equations and furthermore, these are moved into ordinary differential equations. A numerical procedure is applied via shooting/bvp4c to obtain numerical results. Inclined magnetic dipole gives a lower velocity of Carreau nanofluid. Due to the relaxation time factor velocity of Carreau fluid gets down. A* causes to generate the heat internally, so due to this, temperature increases rapidly. The increasing rate of temperature is found very high for the growing Hartmann number. The rate of mass transport becomes low for gradual increment in the parameter of thermophoresis, wedge angle, and Prandtl. Inclined magnetic dipole gives a lower velocity of Carreau nanofluid. Due to the relaxation time factor, the velocity of the Carreau fluid goes down. The absence and presence of magnetic numbers have no influence on velocity, temperature, and concentration files for Le, R_d, θ_f, γ, We, β, Pr, Nb, Nt, A.     

Design of inner containment tanks for liquid oxygen and liquid nitrogen

The design and construction of inner containment tanks for liquid oxygen and liquid nitrogen is discussed. Standards and recommendations by official bodies are cited and potential failure areas are highlighted.     

The Relation of Children's Everyday Nonsocial Peer Play Behavior to Their Emotionality, Regulation, and Social Functioning.

The relations of children's nonsocial behavior to their emotionality, regulation, and social functioning were examined in a short-term longitudinal study. Parents (primarily mothers) and teachers rated children's effortful regulation, emotionality, asocial behaviors, problem behaviors, and social acceptance, and children's nonsocial play behaviors were observed for two semesters. Peers also rated likability. Children's observed reticent activities were related to adults' ratings of high regulation, low externalizing problems, and high asocial behavior, as well as to low anger and low positive emotion. On the other hand, solitary play was associated with low positive emotion and low regulation over time and with high asocial behavior and high peer exclusion. Peer rejection mediated the relation of internalizing emotions (anxiety, low positive emotion) and regulation to solitary play later in the school year, and asocial play mediated the relation of internalizing emotions to both solitary and reticent play behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forced unsteady state operation to improve H2 permeability through Pd-Ag membrane during start-up

Hydrogen separation from nitrogen containing gas mixture using Pd-Ag membrane shows a time lag and low hydrogen recovery during start-up period. In this study, forced unsteady state operation using a composition modulation of the feed gas was employed as a new operation method to increase the hydrogen recovery and to shorten the time lag. In this work, the performance of Pd75-Ag25 membrane during the separation of hydrogen from H₂/N₂ mixture under forced unsteady state operation at 623 K was investigated. During natural start-up without forced operation, the hydrogen recovery results in 35% and 14% for H₂/N₂ feed gas compositions of 70%/30% and 50%/50%, respectively, while the time lag in the natural operation results in 195 and 147 min for H₂/N₂ feed gas compositions of 70%/30% and 50%/50%, respectively. The experimental results show that forced unsteady state operation affects considerably on hydrogen recovery from H₂/N₂ mixture and the time lag during start-up. The maximum hydrogen recovery in the forced unsteady state operation is 60%, obtained at switching time 5 min and H₂/N₂ feed gas composition of 70%/30%, while for H₂/N₂ feed gas composition of 50%/50% the hydrogen recovery is not significantly influenced by switching time. The time lag indicates a profound decay trend monotonically by decreasing the switching time for both H₂/N₂ feed gas compositions.     

Analysis of optimal centroid estimation applied to Shack-Hartmann sensing

The problem of estimating the centroid of an incoherently imaged point with a CCD array is analyzed. An exact analysis is presented that uses the actual short-exposure function at the CCD instead of the traditional Gaussian approximation. The analysis shows that, for Poisson noise, the centroid variance depends on the CCD size and that truncation effects play a significant part in determining the optimum CCD size. The effects of this on a wave-front reconstruction formed by a Shack-Hartmann sensor are described.     

Photografting of methacrylic acid on polyethylene film: Effect of mixed solvents consisting of water and organic solvent

Photografting of methacrylic acid (MAA) on linear low‐density polyethylene film (thickness = 30 μm) was investigated at 60°C in mixed solvents consisting of water and organic solvent with xanthone as the photoiniator. The organic solvents examined were acetone, methanol, tetrahydrofuran, and dioxane. A maximum percentage of grafting was observed at a certain concentration of organic solvent in the mixed solvent, depending on the nature of the organic solvent. Distribution of the grafted chains in the resultant MAA‐grafted film, which was examined by scanning electron microscopy and attenuated total‐reflection IR spectroscopy, was largely influenced by the use of the mixed solvent. The grafted samples swelled in the alkaline region and shrank in acidic medium, showing a pH‐responsive character. The extent of the pH‐responsive function was closely related to the location of grafted chains, which could be controlled by proper choice of the composition of organic solvent in the mixed solvent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2454–2461, 2002