Preparation of microbial agent immobilized composites for Cr(VI) removal from wastewater.

Because of its extreme toxicity and health risks, hexavalent chromium [Cr(VI)] has been identified as a major environmental contaminant. Bioreduction is considered as one of effective techniques for cleaning up Cr(VI)-contaminated sites, but the remediation efficiency needs to be enhanced. Here, a novel immobilized microbial agent was produced by immobilizing ZY-2009 with sodium alginate (SA) using polyvinyl alcohol (PVA) and activated carbon (AC).

Locking the Spiro Carbon in Spirobisindane Using Sulfur and Phosphorus to Form "Olympic Ring"-like Molecules.

To improve the rigidity of spirobisindane, it was intramolecularly locked by forming eight-membered rings via sulfur and phosphorus atoms to produce an interlocked polycyclic structure under mild conditions in good yields. By carefully analyzing the crystal structures, we noticed that the angle between the two benzene rings in the locked version is significantly smaller than that of the typical spirobisindane structure. Molecular modeling indicated that locking the spiro center can remarkably enhance the rigidity.

Hexavalent chromium removal by a resistant strain ZY-2009.

Bioreduction of Cr(VI) to Cr(III) by reducing microbes has attracted increasing concern. Here, Cr(VI) removal capacity of a Cr(VI)-resistant bacterium isolated from activated sludge was investigated. Based on its physio-biochemical attributes and 16S rDNA sequence analysis, the strain was identified as ZY-2009.

Guanidinylated Amphiphilic Polycarbonates with Enhanced Antimicrobial Activity by Extending the Length of the Spacer Arm and Micelle Self-Assembly.

Nine guanidinylated amphiphilic polycarbonates are rationally designed and synthesized. Each polymer has the same biodegradable backbone but different side groups. The influence of the hydrophobic/hydrophilic effect on antimicrobial activities and cytotoxicity is systematically investigated.

A Versatile 3D and 4D Printing System through Photocontrolled RAFT Polymerization.

Reversible addition-fragmentation chain-transfer (RAFT) polymerization is a valuable tool for synthesizing macromolecules with controlled topologies and diverse chemical functionalities. However, the application of RAFT polymerization to additive-manufacturing processes has been prevented due to the slow polymerization rates of typical systems. In this work, we developed and optimized a rapid visible (green) light mediated RAFT polymerization process and applied it to an open-air 3D printing system.

Effective Conversion of Amide to Carboxylic Acid on Polymers of Intrinsic Microporosity (PIM-1) with Nitrous Acid.

Carboxylate-functionalised polymers of intrinsic microporosity (C-PIMs) are highly desirable materials for membrane separation applications. The recently reported method to afford C-PIMs was via an extensive base hydrolysis process requiring 360 h. Herein, a novel and effective method to convert PIM-CONH₂ to C-PIM using nitrous acid was studied.

Molecular Weight and Charge Density Effects of Guanidinylated Biodegradable Polycarbonates on Antimicrobial Activity and Selectivity.

Six guanidine functionalized aliphatic biodegradable polycarbonates with varying molecular weights and charge densities were synthesized via postsynthesis modification of alkyne containing polycarbonates using Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry. The concept of passive diluting group was to modify the cationic charge density of the polycarbonate without changing its hydrophilicity. Within the molecular weight range from 8000 to 30000 g mol, these guanidine polycarbonates exhibited broad-spectrum biocidal activity with low toxicity to red blood cells (RBCs).

The enhancement of chain rigidity and gas transport performance of polymers of intrinsic microporosity via intramolecular locking of the spiro-carbon.

Here, we present a new strategy to improve the rigidity of through the introduction of 8-membered ring locking into the flexible spiro-carbon pivot point to produce an interlocked polycyclic structure. This locked version of shows simultaneous increases in both permeability and selectivity that place it well above the Robeson upper bound for a number of important gas pairs. Molecular modelling demonstrates that the locked version of is much more rigid.

Light-responsive in situ forming injectable implants for effective drug delivery to the posterior segment of the eye.

Introduction: Frequent intravitreal injections are currently the preferred treatment method for diseases affecting the posterior segment of the eye. However, these repeated injections have been associated with pain, risk of infection, hemorrhages, retinal detachment and high treatment costs. To overcome these limitations, light-responsive in situ forming injectable implants (ISFIs) may emerge as novel systems providing site-specific controlled drug delivery to the retinal tissues with great accuracy, safety, minimal invasiveness and high cost efficiency.

Evaluation of gallic acid loaded zein sub-micron electrospun fibre mats as novel active packaging materials.

The applicability of gallic acid loaded zein (Ze-GA) electrospun fibre mats towards potential active food packaging material was evaluated. The surface chemistry of the electrospun fibre mats was determined using X-ray photon spectroscopy (XPS). The electrospun fibre mats showed low water activity and whitish colour.

Encapsulation of food grade antioxidant in natural biopolymer by electrospinning technique: a physicochemical study based on zein-gallic acid system.

Gallic acid was successfully incorporated into zein ultra-fine fibres at different loading amount (5%, 10% and 20%) in order to develop an encapsulating technology for functional ingredient delivery using electrospinning. The produced fibres exhibit diameters ranging from 327 to 387 nm. The physical and thermal properties of encapsulated gallic acid were determined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC); and the interaction between gallic acid and zein was attested by attenuated total reflection-Fourier transform infrared (ATR-FTIR).

Effect of mesoscopic fillers on the polymerization induced viscoelastic phase separation at near- and off-critical compositions.

We have investigated the effect of mesoscopic fillers on the polymerization induced viscoelastic phase separation of thermoplastic modified thermosets at near- and off-critical concentrations using optical microscopy, time-resolved light scattering, dynamic mechanical analyses, and rheological instrument. Mesoscopic fillers including sepiolite and nanosized silica showed a significant enhancement effect in viscoelastic phase separation, and resulted in pronounced differences in the phase structures at all concentrations of polyetherimide modified epoxy resins with dynamic asymmetry. For blends near critical concentration, the introduction of fillers led to much finer phase structure with smaller characteristic length scale.

Synthesis and electronic factors in thermal cyclodimerization of functionalized aromatic trifluorovinyl ethers.

A series of 19 p-substituted aromatic trifluorovinyl ether compounds were prepared from versatile intermediate p-Br-C(6)H(4)-O-CF=CF(2) and underwent thermal radical mediated cyclodimerization to new difunctional compounds containing the 1,2-disubstituted perfluorocyclobutyl (PFCB) linkage. The synthetic scope demonstrates the functional group transformation tolerance of the fluorovinyl ether, and the dimers are useful as monomers for traditional step-growth polymerization methods. (19)F NMR spectra confirmed that p-substitution affects the trifluorovinyl ether group chemical shifts.