Gene Cloning,Overexpression, and Characterization of the Nitrilase from <Emphasis Type="Italic">Rhodococcus rhodochrous</Emphasis> tg1-A6 in <Emphasis Type="Italic">E. coli</Emphasis>

A DNA fragment containing the entire coding sequence of nitrilase gene was amplified from Rhodococcus rhodochrous tg1-A6 with high nitrilase activity using PCR and sequenced. The open reading frame of the nitrilase gene contains 1,101 base pairs, which encodes a putative polypeptide of 366 amino acid residues. The nitrilase gene was cloned into an expression vector pET-28a and expressed in an Escherichia coli strain BL21(DE3). The enzymatic activity of nitrilase, which converts various nitriles to the corresponding carboxylic acids, was detected to reach 24.5 U/ml at 9 h in the recombinant bacteria.     

Quantum dots sensitized graphene: In situ growth and application in photoelectrochemical cells

A novel photoelectrochemical cells (PEC) based on quantum dots (QDs) sensitized graphene for light harvesting and energy conversion was described in this work. QDs sensitized graphene was prepared by in situ growth of QDs on noncovalently functionalized graphene. QDs sensitized graphene photoelectrodes showed enhanced photocurrent generation capability and incident photon-to-electron conversion efficiency (IPCE) at visible light, and could also be an efficient platform for other optoelectronic applications.     

Predicting the shock sensitivity of cyclotrimethylene-trinitramine

We studied the surface and thermal properties of seven different varieties of cyclotrimethylene-trinitramine (RDX) crystalline explosives from five manufacturers using differential scanning calorimetry (DSC) and atomic force microscopy (AFM). The specific varieties of the RDX studied were acquired from the previous Reduced Sensitivity RDX Round Robin program. They were chosen because intensive characterization of the materials already existed including shock sensitivity and cyclotetramethylene-tetranitramine (HMX) impurity levels. AFM scans revealed a diversity of surface defects. To quantify the surface defects on the crystalline surface of the RDX particles, surface roughness measurements were acquired. Statistical analysis was undertaken to correlate the observed surface, HMX impurity levels, and DSC thermal curve properties with the known shock sensitivities of the material. It was determined that a statistically significant relationship exists between surface roughness and the shock sensitivity of the material while no relationship was observed between the DSC thermal properties and either surface roughness or shock sensitivity. The HMX content greatly affected the thermal properties of RDX but was uncorrelated with the shock sensitivity.     

Thermal properties and liquid crystallinity of side-chain azobenzene copolymer containing pendant polyhedral oligomeric silsequioxanes

Vinylated polyhedral oligomeric silsesquioxane (POSS-M) was prepared by the reaction of POSS containing amine groups with acrylic acid. Azobenzene liquid crystalline copolymer (LCP-POSS) was then synthesized with 6.0 mol% POSS-M and 94.0 mol% acrylate monomer containing azobenzene liquid crystalline moiety (Azo-M) by free-radical copolymerization. Homopolymer of Azo-M (LCP) was also synthesized under the same conditions. Their thermal properties and liquid crystallinity were characterized by Thermal gravimetric analysis (TG), differential scanning calorimetry (DSC), Wide-angle X-ray diffraction experiments (XRD) and polarized optical micrographs (POM). The results showed that LCP-POSS has higher thermal stability and glass transition temperature than pure LCP due to the incorporation of the rigid cage-like POSS. Especially, LCP-POSS exhibits enantiotropic smectic and nematic liquid crystalline behaviors, its smectic-nematic transition temperature (T _SN) and nematic-isotropic transition temperature (T _NI) are higher than those of pure LCP, which may promote and extend its applications on stimuli-responsive materials and devices.     

A Polycation Scaffold Presenting Tunable “Click” Sites: Conjugation to Carbohydrate Ligands and Examination of Hepatocyte‐Targeted pDNA Delivery

A versatile polycation scaffold that can easily be modified with targeting ligands has been designed, synthesized, and characterized. A series of galactose‐containing polymers has been produced to demonstrate the ease of modification of this polynucleotide delivery vehicle motif via the click reaction and to study how various structural modifications affect recognition by ASGPr on hepatocytes. A small library of structures was created where DCS and alkyl spacer length between the targeting group and the polymer backbone was varied. The novel polymer scaffold described proves to be a valuable tool for understanding structure/activity relationships of complexes made with receptor‐targeted polymers.

     

Nanomaterial-based surface-assisted laser desorption/ionization mass spectrometry of peptides and proteins

We have investigated six nanomaterials for their applicability as surfaces for the analyses of peptides and proteins using surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). Gold nanoparticles (NPs) were useful nanomateriais for small analytes (e.g., glutathione); Pt nanosponges and Fe₃O₄ NPs were efficient nanomaterials for proteins, with an upper detectable mass limit of ca. 25 kDa. Nanomateriais have several advantages over organic matrices, including lower limits of detection for small analytes and lower batch-to-batch variations (fewer problems associated with “sweet spois”), when used in laser desorption/ionization mass spectrometry.     

Ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and ionic radii of element Uus (Z = 117) and astatine

Multiconfiguration Dirac-Fock (MCDF) method was employed to calculate the first five ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and radii for the element Uus and its homologue At. Main valence correlation effects were taken into account. The Breit interaction and QED effects were also estimated. The uncertainties of calculated IPs, EAs, and IR for Uus and At were reduced through an extrapolation procedure. The good consistency with available experimental and other theoretical values demonstrates the validity of the present results. These theoretical data therefore can be used to predict some unknown physicochemical properties of element Uus, Astatine, and their compounds.     

A molecular dynamics simulation of a homogeneous organic-inorganic hybrid silica membrane

A new molecular dynamics simulation method was successfully applied to construct a homogeneous organic-inorganic hybrid silica membrane using the hybrid-pcff (h-pcff) potential function. Analysis suggested that the hybrid BTESE silica membrane provided a looser network and larger cavity size for the enhancement of gas permeability and selectivity.     

Chemical composition and bioactivities of the marine alga Isochrysis galbana from Taiwan

The present study investigated the chemical composition of Isochrysis galbana Parke, a marine microalga which is widely used as a feedstock in aquaculture. From gas chromatography/mass spectrometric analysis the mono-sugar compositions of I. galbana were 2.1% fucose, 2.5% rhamnose, 2.7% arabinose, 8.5% xylose, 15.7% mannose, 32.7% galactose and 35.8% glucose. The polysaccharides of I. galbana were able to induce prointerleukin-1beta (pro-IL-1beta) protein expression within murine macrophages. Furthermore, five kinds of chlorophyll and one sterol were separated from the ethanolic extracts, including pheophorbide-a, ethyl pheophorbide-a, 10S-10-hydroxypheophytin-a, 10R-10-hydroxypheophytin-a, (132-R)-pheophytin-a, and brassicasterol. In addition, the major soluble components of the ethanol/n-hexane extract were 9-octadecenoic acid (E) (38.4%), hexadecanoic acid (23.3%), tetradecanoic acid (15.7%), and octadecanoic acid (7.2%), but only a few polyunsaturated fatty acids were found, such as 9,12,15-octadecatrienoic acid (1.9%), 9,12-octadecadienoic acid (Z,Z) (3.4%), and docosahexaenoic acid (0.2%). This is the first occasion that polysaccharides from I. galbana have been demonstrated to exert immunomodulatory properties by the induction of IL-1 within macrophages.