Polypeptides with High Zwitterion Density for Safe and Effective Therapeutics

The commonly used “stealth material” poly(ethylene glycol) (PEG) effectively promotes the pharmacokinetics of therapeutic cargos while reducing their immune response. However, recent studies have suggested that PEG could induce adverse reactions, including the emergence of anti‐PEG antibodies and tissue histologic changes. An alternative stealth material with no or less immunogenicity and organ toxicity is thus urgently needed. We designed a polypeptide with high zwitterion density (PepCB) as a stealth material for therapeutics. Neither tissue histological changes in liver, kidney, or spleen, nor abnormal behavior, sickness or death was induced by the synthesized polymer after high‐dosage administration for three months in rats. When conjugated to a therapeutic protein uricase, the uricase–PepCB bioconjugate showed significantly improved pharmacokinetics and immunological properties compared with uricase–PEG conjugates.     

Novel gold dendritic nanoflowers deposited on titanium nitride for photoelectrochemical cells

This study demonstrates the elaboration of a novel composite comprising gold dendritic nanoflowers (Au DNFs)/titanium nitride (TiN)/silicon (Si); this composite can be used for methanol oxidation reactions in alkaline electrolytes. Cyclic voltammograms showed that a thick (650 nm) Au DNFs/TiN/Si (L-DNFs-TiN) composite had double the oxidation current density of a thick (800 nm) Au DNFs/Si (L-DNFs-Si) composite in the presence of light illumination, whereas the oxidation current density for a thin (250 nm) Au DNFs/Si (S-DNFs-Si) composite and Au nanoparticles could not be determined. Chronoamperometry (CA) testing indicated that the L-DNFs-TiN could absorb light illumination more effectively than the L-DNFs-Si did. These results correspond to the broadband light absorption of TiN. Testing with continuous cyclic on/off light illumination showed a repeatable performance in CA, indicating that the proposed L-DNFs-TiN composite can be applied in photoelectrochemical cells in the future.     

Synthesis of Cardioactive Steroids III Modified Synthetic Route to Isocardenolide

A modified synthetic route to isocardenolide (I) via furan intermediate (6) was studied. The diene (4) could easily be synthesized from carbinol (1) or acetate (2). Dissolving metal reduction of diene (4) to Δ¹, 17β-furyl compound (6) was successfully achieved.     

Enhanced effect of RM-β-cyclodextrin on biodegradation of toluene in wastewater by activated sludge

Recently, air and ground water pollution and contamination of soil by toluene have been drawing increasing attention and became an urgently important problem in environmental pollution. Hence, the development of highly sophisticated removal techniques of toluene is required for the global environmental preservation. Since toluene is a highly volatile material, it is difficult to treat it by usual activated sludge water treatment. In this study, in order to prevent volatilization of toluene, randomly methylated β-cyclodextrin (RM-β-CD) was used to complex with toluene and by reason of that, facilitates the biodegradation of toluene by activated sludge. The enhanced effect of RM-β-CD for the biodegradation of toluene by activated sludge was studied in batch systems. The addition of RM-β-CD dominantly promoted proliferation of activated sludge. This implied that the addition of RM-β-CD prevented toluene from evaporating during treatment, and as a result, toluene was effectively decomposed by the activated sludge.     

Release kinetics of (−)-menthol from chewing gum

The release kinetics of (−)-menthol from chewing gum was investigated using various encapsulated powder of (−)-menthol. The apparatus of flavor release of chewing gum was made with a glass container of mashing homogenizer. Flavor release behavior could be correlated with Avrami’s equation. Chewing gum containing (−)-menthol/γ-CD complex powder had longer retention of (−)-menthol compared with the β-CD complex powder and the (−)-menthol encapsulated in modified starches. The activation energies of (−)-menthol release from chewing gum were 106 kJ/mol for γ-CD complex and 74 kJ/mol for (−)-menthol/β-CD complex powder and emulsified (−)-menthol encapsulated in HI-CAP, respectively.     

Synthesis and Functionalization of Isotactic Poly(propylene) Containing Pendant Styrene Groups

Summary: Copolymerization of propylene and 1,4‐divinylbenzene was successfully performed by a MgCl₂‐supported TiCl₄ catalyst, yielding isotactic poly(propylene) (i‐PP) polymers containing a few pendant styrene groups. With a metalation reaction with butyllithium and a hydrochlorination reaction with dry hydrogen chloride, the pendant styrene groups were quantitatively transformed into benzyllithium and 1‐chloroethylbenzene groups, respectively, which allowed the synthesis of i‐PP‐based graft copolymers by living anionic and atom transfer radical (ATRP) polymerization mechanisms.

The incorporation of styrene pendant groups into isotactic poly(propylene) using a Zeigler–Natta catalyst gave functionalized polymers able to undergo living anionic and atom transfer radical (ATRP) polymerizations.     

Controlling of Solution Concentration on Nucleation During Hydrothermal Synthesis of Analcime

Hydrothermal experiments of analcime nucleation and glass dissolution were carried out in autoclaves under the conditions of autogeneous pressures, temperatures of 150 °C ～ 210 °C, and 0.25 M ～ 0.75 M NaOH solutions. The curves of the glass dissolution and analcime formation are S‐shaped. Yet, the two curves are essentially parallel to each other. The time required for a complete dissolution of glass or the commencement of analcime formation is shorter when the concentration of NaOH solution or the temperature is higher. The amount of the weight percent of analcime synthesized is obviously less than the glass dissolved at a given time of an experiment. The weight difference between glass dissolved and analcime (dehydrated) formed is calculated to be represented as the solution concentration. During an experiment, the solution concentration increases gradually to a maximum, then decreases slowly to a constant value with time. On the other hand, nucleation is also gradually increased to a maximum, then is decreased finally to zero with time in a bell‐shaped curve. It is clear that nucleation of analcime is mainly controlled by the solution concentration.     

Comparison of radii sets,entropy, QM methods,and sampling on MM‐PBSA,MM‐GBSA,and QM/MM‐GBSA ligand binding energies of F. tularensis enoyl‐ACP reductase (FabI)

To validate a method for predicting the binding affinities of FabI inhibitors, three implicit solvent methods, MM‐PBSA, MM‐GBSA, and QM/MM‐GBSA were carefully compared using 16 benzimidazole inhibitors in complex with Francisella tularensis FabI. The data suggests that the prediction results are sensitive to radii sets, GB methods, QM Hamiltonians, sampling protocols, and simulation length, if only one simulation trajectory is used for each ligand. In this case, QM/MM‐GBSA using 6 ns MD simulation trajectories together with GB^neck2, PM3, and the mbondi2 radii set, generate the closest agreement with experimental values (r² = 0.88). However, if the three implicit solvent methods are averaged from six 1 ns MD simulations for each ligand (called “multiple independent sampling”), the prediction results are relatively insensitive to all the tested parameters. Moreover, MM/GBSA together with GB^HCT and mbondi, using 600 frames extracted evenly from six 0.25 ns MD simulations, can also provide accurate prediction to experimental values (r² = 0.84). Therefore, the multiple independent sampling method can be more efficient than a single, long simulation method. Since future scaffold expansions may significantly change the benzimidazole's physiochemical properties (charges, etc.) and possibly binding modes, which may affect the sensitivities of various parameters, the relatively insensitive “multiple independent sampling method” may avoid the need of an entirely new validation study. Moreover, due to large fluctuating entropy values, (QM/)MM‐P(G)BSA were limited to inhibitors’ relative affinity prediction, but not the absolute affinity. The developed protocol will support an ongoing benzimidazole lead optimization program. © 2015 Wiley Periodicals, Inc.