Production and rheological characterization of biopolymer of Sphingomonas capsulata ATCC 14666 using conventional and industrial media

This work was aimed at the production and rheological characterization of biopolymer by Sphingomonas capsulata ATCC 14666, using conventional and industrial media. The productivity reached the maximum of 0.038 g/L·h, at 208 rpm and 4% (w/v) of sucrose. For this condition, different concentrations of industrial medium were tested (2.66, 4, 6, and 8%). The best productivity was obtained using pretreated molasses 8% (w/v) (0.296 g/L·h), residue of textured soybean protein 6% (wt/v) (0.244 g/L·h) and crude molasses 8% (w/v) (0.192 g/L·h), respectively. Apparent viscosity presented similar results when compared with those in the literature for other biopolymers.     

Photoinduced alkyl group exchange of ethylzinc alkoxides: X-ray crystal structure of an iodomethylzinc methoxide

Irradiation of a solution of ethyl zinc alkoxides and CH2I2 leads to clean formation of iodomethylzinc alkoxides; these intermediates are important species generated in stereoselective cyclopropanation processes; no alkyl group exchange is observed in the absence of irradiation; the solid-state structure of (MeO)8Zn7(CH2I)6 is also reported.     

Separation and quantification by high-performance liquid chromatography with light scattering detection of the main wheat flour phospholipids during dough mixing in the presence of phospholipase

Phospholipids (PL) are minor components of wheat flour involved in baking quality and exogenous phospholipids are used as emulsifiers giving better loaf volume and crumb grain. Few biochemical data are available on the phospholipid evolution during mixing, probably because of the time-consuming methods proposed for their extraction, separation and quantification. In the present study, the extraction, separation and quantification of the main wheat flour phospholipids were carried out. Total lipids (2% dry mass of wheat flour) were extracted from flour or dough by a mixture of chloroform-methanol-water (1:1:1 (v/v)). The phospholipids were separated from the lipid extract on silica cartridge by solid-phase extraction (SPE) procedure under a 1.5-4 mmHg vacuum, at a 0.8 mL min(-1) flow rate (1 mmHg = 133.322 Pa). The recovery of the lipid extract was 100%, whereas the SPE yield for the PLs was 50%. The resulting fraction was then submitted to HPLC with evaporative light scattering detection on a Diol stationary phase allowing the separation and quantification of each class of phospholipids, in less than 16 min. The developed method allowed to quantify the phospholipid amounts from eight wheat flours as well as their evolution during mixing in the presence of phospholipase.     

Two-fold amino acid-based chiral aminophosphine-oxazolines and use in asymmetric allylic alkylation

Chiral aminophosphine-oxazoline ligands derived from two different amino acids (tetrahydroisoquinoline carboxylic acid and proline) have been synthesized and examined as chiral auxiliaries in asymmetric allylic alkylation of three substrates. Stereoisomers 1a and 2a are providing the highest enantioselectivities (up to 94% ee) in the allylation of diphenylpropenyl acetate.     

Redetermination of the O-O bond length in the dioxygen-adduct of Vaska’s complex

Solid state structural studies were performed with (Ph₃P)₂IrCl(CO)(O₂) and the O-O length redetermined to be 1.47(1) Å in contrast to results reported earlier.     

Crystal structure,vibrational spectra and thermal decomposition study of a new,dicationic, acidic pyrophosphate: KHMgP<Subscript>2</Subscript>O<Subscript>7</Subscript>⋅2H<Subscript>2</Subscript>O

Colourless crystals of a new, dicationic, hydropyrophosphate dihydrate salt, KHMgP₂O₇⋅ 2H₂O, are formed, when a mixture of aqueous equimolar solutions of MgCl₂⋅4H₂O and K₄P₂O₇, at pH 2.12, are left to stand at ambient temperature for 4 days. The new pyrophosphate salt has been characterized by single-crystal X-ray diffraction, IR and Raman spectra, and DSC-TG thermal analysis. The structure consists of alternating layers of [HP₂O₇]³⁻ groups and MgO₆ octahedra, joined by K⁺ ions and bridging hydrogen bonds. The [P₂O₇]⁴⁻ anions exhibit a bent eclipsed conformation. The absence of coincidences for the majority of the IR and Raman bands is in accord with the centrosymmetric structure of the material. The ³¹P chemical shift tensor components have been determined from the solid-state MAS NMR spectra. The structural changes occurring during thermal decomposition have been examined by TG-DSC, X-ray powder diffraction (XRD) and IR spectroscopy. When the new pyrophosphate salt is heated gradually, it first becomes amorphous and then condenses to chain metaphosphates.     

Crystal structure and solid-state31P CP-MAS NMR spectrum of the bis(trifluoroacetato) (triphenylphosphine)mercury(II) dimer [Hg(CF3CO2)2PPh3]2

The title compound belongs to the monoclinic space groupP2₁/c,a=20.29(1),b=12.644(8),c=18.25(1), Å,=95.76(5)°. The unit cell contains two dimeric [Hg(CF₃CO₂)₂PPh₃]₂ molecules in which each Hg atom forms strong primary bonds to a PPh₃ molecule and an oxygen of a monodentate trifluoroacetate ligand. These two Hg atoms are bridged by two extra trifluoroacetate ligands, one providing a single oxygen to a Hg-O-Hg bridge, the other including both carboxylate oxygens in a Hg-O-C-O-Hg bridging moiety. This unusual type of bridging makes the two halves of the molecule symmetry independent, leading to distinct signals at 31.5 and 29.9 ppm for the phosphines in the³¹P CP-MAS NMR spectrum of the solid complex.     

Geographical variation in residence and risk of multiple nonmelanoma skin cancers in US women and men

Residence in high ultraviolet (UV) locations is associated with increased risk for incident nonmelanoma skin cancer (NMSC). However, the effect of geographic location on multiple NMSC development has not been well studied. We evaluated the association between state of residence at birth, age 15 and 30 and risk of multiple NMSCs among 80275 women and men. After adjusting for age, gender, hair color, number of sunburns, tanning ability, family history of melanoma and nevus count, the cumulative relative risks (RRs) of developing ≥1 NMSC for those consistently residing in medium- and high-UV index states were 1.20 (95% CI 1.14-1.27) and 1.42 (95% CI 1.32-1.53) respectively. We found that compared to individuals with one lifetime NMSC, the multivariate cumulative RRs of developing ≥2 NMSCs for those who stayed in medium- and high-UV index states at all three timepoints were 1.09 (95% CI 1.00-1.19) and 1.15 (95% CI 1.02-1.30) respectively. These results cannot account for migration during the interval period and seasonal changes in residence; further, as BCC is the predominant NMSC, the results may be BCC-driven. In conclusion, we found that consistent residence in medium- or high-UVR locations was significantly associated an incremental risk of ≥2 NMSCs later in life.     

Synthesis of a new fluorinated fluorescent β-cyclodextrin sensor

The synthesis of a new fluorescent sensor incorporating a fluorinated indolizine unit bound to 6-amino-β-cyclodextrin by two different synthetic ways is described. Its sensing ability toward adamantanol has been demonstrated.