The effect of compositions and combinations of the reactants upon the copolycondensation of isophthalic acid/terephthalic acid with a combination of hydroquinones and bisphenols by tosyl chloride/dimethylformamide/pyridine

Copolycondensation of isophthalic acid (IPA)/terephthalic acid (TPA) with various combinations of 2,2‐bis(4‐hydroxyphenyl)propane (BPA) and hydroquinones (HQs) or bisphenols (BPs) was conducted to study the effects of the compositions of IPA/TPA and of BPA/HQs or BPA/BPs upon the reaction. Different from homopolycondensation of each of diol components examined where most of the reaction was facilitated by lower contents of IPA at about 70 mol %, the copolycondensation was influenced by a combination of diol components. With chlorohydroquinone (ClHQ) or bis(4‐hydroxyphenyl)sulfone (BPS) having a polar chlorine or sulfonyl substituent, the reaction proceeded most satisfactorily at IPA/TPA = 30/70, whereas it was IPA/TPA = 50/50 for the reaction with nonpolar methyl substituted methylhydroquinone (MeHQ). The reaction with 2,2‐bis(3,5‐dichloro‐4‐hydroxyphenyl)propane (TC‐BPA), despite having polar chlorine substituents in TC‐BPA, was not affected by IPA/TPA compositions. Alternatively, from the viewpoint of the compositions of diol components, the reactions containing 30–50 mol % of HQs or BPS yielded better results except for the reaction of IPA/TPA = 70/30, in which higher contents of MeHQ was more favorable. On the basis of sequence distributions of diol components in the resultant copolymers determined by NMR, compositions of IPA/TPA or diol components and combinations of the diols producing random copolymers yielded better results in copolycondensation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1100–1106, 2004     

Radial dose distribution around a heavy ion''s path

Ionization currents produced in a small wall-less ionization chamber located at varying distance from the 200 MeV Ni¹²⁺ ion's path traversing Ar gas were measured and utilized to construct a track structure model. Using the LET value of 200 MeV Ni¹²⁺ and G(Fe³⁺) in Fricke solutions (= 15.4) for fast electrons, we estimate G(Fe³⁺) for 200 MeV Ni¹²⁺ to be 5.0.     

Synthesis and antitumor activities of novel benzoylphenylurea derivatives.

Seventy novel benzoylphenylurea compounds were synthesized and their antitumor activities were examined in vivo against P388 leukemia. N-(2-Nitrobenzoyl)-N'-[4-(2-pyrimidinyloxy)phenyl]ureas showed the highest antitumor activities when dosed intraperitoneally or orally. Their structure-activity relationships were examined with particular focus on the position and the variety of substituent on each aryl ring.     

An assignment problem for a parallel queueing system with two heterogeneous servers

In this paper, we consider an optimization problem for a parallel queueing system with two heterogeneous servers. Each server has its own queue and customers arrive at each queue according to independent Poisson processes. Each service time is independent and exponentially distributed. When a customer arrives at queue 1, the customers in queue 1 can be transferred to queue 2 by paying an assignment cost which is proportional to the number of moved customers. Holding cost is a function of the pair of queue lengths of the two servers. Our objective is to minimize the expected total discounted cost. We use the dynamic programming approach for this problem. Considering the pair of queue lengths as a state space, we show that the optimal policy has a switch over structure under some conditions on the holding cost.     

Brominations of steroidal hormone having alpha,beta-unsaturated ketone, 17-O-acetyltestosterone, in the presence of silver triflate

Bromination of 17-O-acetyltestosterone (17beta-acetoxyandrost-4-en-3-one) (1) was performed with 1, 5, and 10 eq of Br2 in AcOH-Et2O at room temperature. In all cases 2alpha,6beta- (2) and 2alpha,6beta-dibromo-17beta-acetoxyandrost-4-en-3-one (3) were obtained, although the yields were dependent upon the conditions used. Bromination of compound 1 with 10 eq of Br2 in the presence of silver trifluoromethanesulfonate (silver triflate, AgOTf) at room temperature for 12 h gave 2,7alpha-dibromo- (4) and 2,4,7alpha-tribromo-17beta-acetoxy-3-hydroxy-1-methylestra-1,3,5(10)-triene-6-one (5). The formations of the products were inferred on the basis of products obtained under controlled brominations of 1 in the presence of AgOTf, and of those obtained by the brominations of compounds 9-13 also in the presence of AgOTf.     

Fullerometallic ion chemistry: reactions of C(60)Fe+ and C(20)H(10)Fe+ in the gas phase

Fe+ has been attached to buckminsterfullerene, C(60), and corannulene, C(20)H(10), in the gas phase, and the reactivities of C(60)Fe+ and C(20)H(10)Fe+ have been measured with several small inorganic and organic molecules in helium bath gas at 0.35 Torr using a selected-ion flow tube (SIFT) mass spectrometer. Comparisons with measured reactivities of the bare Fe+ ion indicate that the presence of C(60) and C(20)H(10) leads to enhancements in reactivity at room temperature of up to 5 orders of magnitude. Ligation was the only chemistry observed with D(2), N(2), CO(2), CH(4), C(2)H(2), C(2)H(4), SO(2), C(6)D(6), NH(3), H(2)O, and CO, but other channels were observed to compete with adduct formation in the reactions with N(2)O and O(2). The number of molecules sequentially ligated to the ion was different: up to five molecules of ligand added sequentially to Fe+, up to four molecules of ligand were observed to attach to C(60)Fe+, while only up to three molecules added to C(20)H(10)Fe+. C(60)+ and C(20)H(10)+ were observed to be unreactive toward the same ligands. The kinetic results show the influence of carbonaceous surfaces on metal ion reactivity and are interpreted in terms of the nature of the coordination of Fe+ to the carbonaceous surface. Catalytic effects of the carbonaceous surfaces were identified for the reactions with N(2)O and O(2).     

Phosphorescence from the two triplet states of p-benzoquinone and toluquinone vapour

Molecular formulae for the isotropic and anisotropic scattering are derived by considering the internal field acting upon a molecule within a dense medium and its fluctuation caused by density fluctuations. The anisotropic scattering formula of classical theory is retained but modified by the factors of the internal field. The new formula for the isotropic scattering depends sensitively on the principal values of the optical polarizability tensor and on the parameters describing the anisotropic internal field. Assuming the internal field to be given by the semimacroscopic approach of the Onsager-Scholte model with an ellipsoidal cavity, comparison of the calculated isotropic Rayleigh factor with the experimental value allows a prediction of the degree of the cavity anisotropy for different liquid densities.     

3nπ* spectra of benzaldehyde. I. Vapor phosphorescence

Vibrational analysis of the vapor ³nπ* phosphorescence for three isotopic benzaldehydes (B-h₆, B-1d₁, B-Rd₅) shows that the out-of-plane aldehyde hydrogen wagging vibration (ν₂₆) is the most active non-totally symmetric mode in the spectrum. Since the intensity of 26₂⁰ ? 26₁⁰ the mechanism of ν₂₆ activity is primarily as a Franck—Condon mode. The only other out-of-plane mode definitely attributed to the vapor phosphorescence is the weakly active CHO torsional vibration (ν₃₆) with I (36₁⁰) > I (26₁⁰). Other Franck—Condon modes are ν₇, ν₂₅, ν₂₀, ν₁₇ and ν₈.     

Shape deformation and circle instability in two-dimensional lipid domains by dipolar force: a shape- and size-dependent line tension model

The dipolar energy of a solid monolayer domain surrounded by a fluid phase at an air-water interface is derived approximately as a sum of an additionally negative line tension and a curvature-elastic energy at the boundary. Variation of the domain energy yields an equilibrium domain shape equation. The obvious solutions of the domain shape equation clearly predict a circle, torus, D-form, S-form, and serpentine manner shape found experimentally, depending on the difference in the Gibbs free energy between the solid and fluid phases and the total line tension. Analysis of linear instability for a circle with a fixed area shows that, above a threshold size, the circle can be deformed into an m-sided quasipolygon. The good agreement with the observation and numerical calculation reported by Lee and McConnell [J. Phys. Chem. 91, 9532 (1993)]] shows the quantitative validity of the present theory.