Examination of Template Structural Effects on CEC Chiral Separation Performance of Molecule Imprinted Polymers Made by a Generalized Preparation Protocol

Some acidic chiral templates were used to prepare open tubular (OT) molecule imprinted polymer (MIP) capillary columns to explore the effects of molecular structures of templates on chiral recognition capabilities and to verify the feasibility of the general MIP preparation protocol introduced in the previous study. The templates are phenyl carboxylic acids and their derivatives. Optimization was carried out for chiral separation of template enantiomers for each MIP column through varying pH and composition of eluent. It was found that the preparation protocol can be successfully applied for the appropriate templates with functional groups fulfilling the three-points interaction rule. The chiral separation performances were quite satisfactory for MIPs of such templates although they are yet inferior to the separation performances of the MIP columns fabricated with the templates of profen drugs (2-arylpropionic acids with a large substituent on the phenyl ring). Subtle variations of the template molecular structures have been found to be critical to enhance chiral recognition ability of the resultant MIP column.     

Synthesis, structure investigation, spectral characteristics and biological activities of some novel azodyes

Four novel azo compounds were synthesized; o-phenylazo- (C(14)H(13)N(3)O(2)) (I), p-bromo-o-phenylazo- (C(14)H(13)BrN(3)O(2)) (II), p-methoxy-o-phenaylazo- (C(15)H(16)N(3)O(3)) (III) and p-nitro-o-phenylazo-p-acetamidophenol (C(14)H(13)N(4)O(4)) (IV). These compounds were carefully investigated using elemental analyses, UV-vis, FT-IR, (1)H NMR and mass spectra. Also, the effects of p-substituents such as bromo, methoxy and nitro groups on the mass fragmentation pathways of these dyes were studied using Hammet's effects. This research aimed chiefly to threw lights on the structures-stability relationship of four novel newly prepared azo derivatives of p-acetoamidophenol. The data obtained referred to the variation of mass fragmentation pathways with the variation of p-substituent of these dyes which can be used in industry for various dyeing purposes. This variation is also correlated and verified by molecular orbital calculations which were done on ionic forms of these dyes using semi empirical PM3 program. The biological activities of these dyes were also investigated and its structure relationship was correlated.     

Reactions of some new thienothiophene derivatives

Facile and convenient syntheses of bisdimethylthieno[2,3-b]thiophen-2,5-diyl bis(oxazole-2-amine), bis(1H-imidazol-2-amine), bis((3a)-H-indole),[1,2-a]pyrimidine), bis(1H-imidazo[1,2-b][1,2,4]triazole) and bis(9H-benzo[d]imidazo[1,2-a]imidazole) derivatives incorporating a thieno[2,3-b]thiophene moiety from the versatile and readily accessible 1,1'(3,4-dimethylthieno[2,3-b]thiophene-2,5-diyl)-bis(2-bromo-ethanone) (1) are described.     

Theoretical study on the reaction of hydrogen atoms with aniline

The reaction of aniline with hydrogen atom is investigated herein using the hybrid meta-DFT functional of BB1 K. Hydrogen atom is found to preferentially add at an ortho position. However, the fate of the o-(C₆H₅NH₂)H adduct is found to be solely the deactivation of the initial addition channel. The rate constant for the abstraction channel (C₆H₅NH₂ + H → C₆H₅NH + H₂) is fitted by the expression 1.10 × 10⁻¹¹ exp(−4,200/T) cm³ molecule⁻¹ s⁻¹. Our calculated rate constant for the abstraction channel agrees very well with the available experimental measurements. Satisfactory agreement is found between calculated and experimental measurements for the displacement channel (C₆H₅NH₂ + H → C₆H₆ + NH₂). Our detailed analysis for the corresponding displacements in toluene and phenol suggests that the three systems exhibit similar behavior with regard to the relative importance of abstraction and displacement channels.     

A new mixed integer programming formulation for facility layout design using flexible bays

This paper presents a mixed-integer programming formulation to find optimal solutions for the block layout problem with unequal departmental areas arranged in flexible bays. The nonlinear department area constraints are modeled in a continuous plane without using any surrogate constraints. The formulation is extensively tested on problems from the literature.     

Quantum group invariant fermionic gases: GLp,q(2) and SUp/q(2) invariances

We first investigate the high-temperature behavior of a two-parameter deformed quantum group fermionic gas with GL_p,q(2) symmetry, where (p,q)C×C. We then discuss both the structural and thermodynamical differences between GL_p,q(2)- and SU_r(2)-fermions with r=p/q where (p,q)R×R.     

Extremely cold positrons for antihydrogen production

The storage of extremely cold (4 K) antiprotons in a Penning trap is an important step toward the creation and study of cold antihydrogen. The other required ingredient, the largest possible number of comparably cold positrons, is still lacking. These would be recombined in a high vacuum with the trapped antiprotons, already stored at a pressure below 5×10⁻¹⁷ Torr, thereby avoiding annihilation of the antihydrogen atoms before they can be used in high accuracy measurements or in controlled collision experiments. In an exploratory experiment, positrons from a 18 mCi²²Na source follow fringing field lines of a 6 T superconducting solenoid through tiny apertures in the electrodes of a Penning trap to strike a tungsten (reflection) moderator. The positron beam is chopped mechanically and a lock-in directly detects a positron current of 2.5×10⁶e⁺/s on the moderator. The use of a moderator, unlike an earlier experiment in which < 100 positrons were confined in vacuum, should greatly increase the number of positrons trapped in high vacuum.     

Synthesis and synthetic utility of 1-acyl-2-alkyl-4-trimethylstannyl-1,2-dihydropyridines

1-Acyl-2-alkyl-1,2-dihydropyridines were prepared from 4-trimethylstannylpyridine and Grignard reagents. This methodology was utilized in the synthesis of N-methyl-2-azatricyclo[5.3.1.0]undecane.     

New alkaloids from Phoebe grandis (Nees) Merr

The alkaloidal extract of the leaves of Phoebe grandis (nees) merr. have provided two new minor alkaloids; phoebegrandine D (1), a proaporphine-tryptamine dimer, and phoebegrandine E (2), an indoloquinolizidine. This is the first report on the occurrence of an indoloquinolizidine in the Phoebe species. The crude extract also exhibited antiplasmodial activity (IC50<8 microg mL-1). The structures of the novel compounds were elucidated by spectroscopic methods, notably 2D NMR and HRMS.     

X-ray attenuation around <Emphasis Type="Italic">K</Emphasis>-edge of Zr,Nb, Mo and Pd: A comparative study using proton-induced X-ray emission and <Superscript>241</Superscript>Am gamma rays

Mass attenuation coefficients (μ/ρ) for Zr, Nb, Mo and Pd elements around their K-edges are measured at 14 energies in the range 15.744–28.564 keV using secondary excitation from thin Zr, Nb, Mo, Rh, Pd, Cd and Sn foils. The measurements were carried out at the K _α and K _β energy values of the target elements by two techniques: (1) Proton-induced X-ray emission (PIXE) and (2) ²⁴¹Am (300 mCi) source. In PIXE, 2 MeV proton-excited X-rays were detected by a Si(Li) detector. In the second case, X-rays excited by 59.54 keV photons from the targets were counted by an HPGe detector under a narrow beam good geometry set-up with sufficient shielding. The results are consistent with theoretical values derived from the XCOM package and indicate that the PIXE data have better statistical accuracy.