Morphologies of star-block copolymers in dilute solutions

The morphologies of star-block copolymer (AB)n and (BA)n in a selective solvent for A-block are investigated by using dissipative particle dynamics. For a star-block copolymer of (BA)n type with a large enough arm number n, since the solvophobic B-blocks are situated in the inner part of the star, it behaves as a unimolecular micelle with the B-block core and A-block hairy corona. These types of star copolymers repel each other, thus it is quite difficult to form multimolecular micelles. On the other hand, for a star-block copolymer of (AB)n type, a few aggregative domains develop on the outer rim of the molecule. As the length of B-blocks or the repulsive interaction between B-blocks and solvents is increased, the tendency of B-blocks to associate within the star increases and thus the average number of aggregative domains declines. Owing to the exposure of B-domains, (AB)n type star-blocks tend to form micelles with morphology different from typical micelles. Upon performing simulations for solutions with multiple stars, we have shown that the single molecular conformation may greatly affect the resulting morphology of the supramolecular structure, such as connected-star aggregate, multicore micelle, segmented worm, and core-lump micelle.     

Two-phase pricing and inventory management for deteriorating and fashion goods under trade credit

This study models a finite horizon inventory problem for deteriorating and fashion goods under trade credit and partial backlogging conditions. Demand may vary with price or time. The supplier can extend credit to the retailer. As a result, the retailer does not have to pay for goods immediately upon acquiring them, and can instead earn interest on the retail price of the goods between the time they are sold and the end of the credit period. The proposed model considers two-phase pricing and inventory decisions. In other words, it determines both the optimal prices and the lengths of the in-stock and stock-out period. This paper is the first to consider different price decisions for in-stock and stock-out periods under trade credit. We develop an algorithm to determine the optimal pricing and replenishment strategy while still maximizing the total profit. Further, this study shows that the proposed two-phase pricing strategy is superior to a one-phase pricing strategy in terms of profit maximization. Computational analysis illustrates the solution procedures and the impacts of the related parameters on decisions and profits. The results of this study can serve as references for business managers or administrators.     

Increased Conversion to 2,4,6‐Triarylpyrylium Salt: Aldol Cyclotrimerization of Acetophenone in BMImPF6 Ionic Liquid

Substituted acetophenone 1 in BMImPF₆ ionic liquid, heated at 120 °C for 24 h, produces β‐methylchalcone 2 , triarylbenzene 3 , and triarylpyrylium salt 4. BMImPF₆ catalyzes the self‐aldol condensation of 1 , whose cyclotrimerization gives an increased conversion to 4 at the expense of 3 normally obtained from the cyclotrimerization of 1 in common organic solvent.     

A facile and efficient synthesis of aryltriethoxysilanes via sonochemical Barbier-type reaction

A series of aryltriethoxysilanes was synthesized from the reaction mixture of aryl bromide, Mg powder, 1,2-dibromoethane and tetraethyl orthosilicate in THF under ultrasound. This sonochemical Barbier-type reaction provides a simple and efficient method for preparation of aryltriethoxysilanes. The Hiyama cross-coupling reaction of phenyltriethoxysilane with bromobenzene was investigated under different palladium catalysts and Pd(PhCN)₂Cl₂ was found to be the best choice.     

Synthesis of O-Aryl N4-Glycosyl(thiosemicarbazido)phosphonothioates

A reaction of aryl(aryloxy)thiophosphonic acids hydrazides with glycosyl isothiocyanates was studied. Amides of N-(glycosylthioureylene)aryl(aryloxy)thiophosphonic acids were synthesized. The structure and composition of the new compounds were confirmed by the data of IR, ¹H and ³¹P NMR and mass spectra, and by results of elemental analyses.     

Lactic acid production by pellet-formRhizopus oryzae in a submerged system

Monoclonal antibodies (mAbs) of the IgM isotypes were produced from mice immunized with blood forms ofTrypansoma cruzi Y strain. Characterization of the epitope recognized by one of the mAbs, 164C11, as well as the effects of this mAb on complement-mediated lysis and host cell invasion are reported. Immunocytochemical analysis showed that the mAb was reactive with various strains ofT. cruzi (Y, WSL, and Colombiana) as well as other trypanosomatids. The mAb 164C11 demonstrated a high complement-mediated lytic activity against bloodstream trypomastigotes, being more effective than chronic mouse serum. A protein with an apparent molecular weight of 72 kDa was detected by this mAb on all developmental stages ofT. cruzi. Studies using periodate and endoglycosidase treatments suggested that the epitope is not a carbohydrate and seems to be located on the parasite membrane. In addition, preliminary results are presented, suggesting that the72-kDa protein is involved in adhesion/or internalization of bloodstream trypomastigotes.     

Classification of monosubstituted phenyl rings by parametric methods applied to infrared and raman peak heights

A statistical linear discriminant method is used to determine if a carbon, nitrogen or oxygen atom is bonded to a monosubstituted phenyl ring. A pattern vector is developed using peak heights of each of the seventeen active infrared and sixteen active Raman bands characteristic of the ring vibration. The Sadtler Standard Raman Spectra, which includes infrared spectra, served as the data base. The success rate is compared for the use of infrared data only. Raman data only and combined infrared and Raman data normalized by several possible methods.     

Novel Ortho effects detected in the fast atom bombardment mass spectra of substituted bisaryl phosphate antagonists of platelet-activating factor

A series of substituted bisaryl phosphate compounds, (R¹CH₂)⁺ ArOP = O(O^?)(OArR²R₃), was analyzed and characterized by fast atom bombardment mass spectrometry. Abundant fragment ions were observed and correlated with the proposed structures. From fragmentation pattersn, ‘ortho effect’ reactions were demonstrated to have occurred when the phosphoryl oxygen reacted with the (CH₂R¹)⁺ and C?O(OCH₃) substituents in the ortho position, relative to the phosphate group, and displaced the R¹ and OCH₃ groups, respectively, to produce phosphorus containing six-membered rings fused to the aryl moiety. When the (CH₂R¹)⁺ substituents were in the meta position relative to the phosphate group, the ‘ortho effect’ reactions were not observed. However, when the C?O(OCH₃) substituent was in the meta position relative to the phosphate group, an abundant fragment ion containing a five-membered phosphate ring fused to the aryl ring was detected with the original phosphoryl oxygen ortho to both the phosphate oxygen and a formyl group, formed from the original C?O(OCH₃) substituent. All other fragmentations not involving the ‘ortho effect’ reactions were nearly identical for the different structural isomers of the substituted bisaryl phosphate compounds.     

Conversion of biomass to ethanol

In theEscherichia coli cell-free system, the modification of cell extract can be achieved by preparation of the strains carrying additional property or those being induced with a certain gene expression prior to harvesting. In this study, we analyzed the cell-free system with S30 extract containing T7 RNA polymerases (S30 extract-T7pol) prepared from E.coli BL21(DE3) strain, which includes T7 RNA polymerase from extrinsic genes by IPTG induction, as a model for the improvement of the cell-free system. The fact that a significant degree of mRNA degradation was observed in the cell-free system with S30 extract-T7pol indicates the increase of ribonuclease activity was an unfavorable influence derived from the cell-extract modification process. We also showed that this influence was settled by the addition of an effective ribonuclease inhibitor, such as copper (II) ion, to the reaction mixture.