Synthesis and isolation of methyl bismuth cysteine and its definitive identification by high resolution mass spectrometry

After the synthesis and isolation of methylated bismuth cysteine, its initial identification by IR-spectroscopy was performed, whereas for definitive identification, high resolution mass spectrometry (ESI-TOF-MS and LTQ Orbitrap) was carried out.     

SiC polytypes process affected by Ge predeposition on Si(111) substrates

Structural and optical measurements were performed on silicon carbide (SiC) samples containing several polytypes. The SiC samples investigated were grown on (111) Si substrates by solid source molecular beam epitaxy (SSMBE). Several quantities of Ge were predeposited before the growth procedure. The influence of Ge on the SiC polytypes formation was studied by X-Ray, FTIR and μ-Raman characterizations methods. The spectra of the samples with less than one Ge monolayer exhibit a mixture of 2H, 15R and 3C–SiC polytypes. This mixture is due to the mismatch between the heterostructure layers. We propose that the Ge predeposition in the heterostructure can be used to stabilize and unify the polytypes formation.     

Crystalline Pr:SrAl12O19 waveguide laser in the visible spectral region

We fabricated waveguides in Pr:SrAl(12)O(19) crystals by direct femtosecond laser writing. The propagation losses were calculated to be as low as 0.16 dB/cm at a wavelength of 633 nm. Laser oscillation in a diode-pumped waveguide at a wavelength of 643.5 nm was realized. The output power of the waveguide laser was 28.1 mW at a slope efficiency of 8%.     

Application of Linear and Branched Poly(Ethylene Glycol)‐Poly(Lactide) Block Copolymers for the Preparation of Films and Solution Electrospun Meshes

Poly(ethylene glycol)‐poly(lactide) (PEG‐PLA) block copolymers are processed to solvent cast films and solution electrospun meshes. The effect of polymer composition, architecture, and number of anchoring points for the plasticizer on swelling, degradation, and mechanical properties of these films and meshes is investigated as potential barrier device for the prevention of peritoneal adhesions. As a result, adequate properties are achieved for the massive films with a longer retention of the plasticizer PEG for star‐shaped block copolymers than for the linear triblock copolymers and consequently more endurable mechanical properties during degradation. For electrospun meshes fabricated using the same polymers, similar trends are observed, but with an earlier start of fragmentation and lower tensile strengths. To overcome the poor mechanical strengths and an occurring shrinkage during incubation, which may impair the coverage of the wound, further adaptions of the meshes and the fabrication process are necessary.

     

Thermal and environmental stability of poly(4-ethynyl-p-xylylene-co-p-xylylene) thin films

The aim of this paper was to test the thermal and environmental stability of poly(4-ethynyl-p-xylyleneco-p-xylylene) thin films prepared by chemical vapor deposition(CVD) and to optimize the reaction conditions of the polymer.Fourier transformed infrared spectroscopy(FTIR),thermogravimetric analysis(TGA) and fluorescence microscopy were employed to investigate the stability of the reactive polymer coatings in various environmental conditions.Chemical reactivity of the thin films were then tested by Huisgen 1,3-dipolar cycloaddition reaction(‘‘click' reaction).The alkyne functional groups on poly(4-ethynyl-p-xylylene-co-p-xylylene) thin films were found to be stable under ambient storage conditions and thermally stable up to 100 8C when annealed at 0.08 Torr in argon.We also optimized the click reaction conditions of azide-functionalized molecules with poly(4-ethynyl-p-xylylene-co-p-xylylene).The best reaction result was achieved,when copper concentration was 0.5 mmol/L,sodium ascorbate concentration to copper concentration was 5:1.In contrast,the azide concentration and temperature had no obvious effect on the surface reaction.