Identification of vortical structures inside the human pharynx/larynx region from POD-reconstructed velocity fields

This paper reports an experimental investigation of the vortical structures in the pharynx/larynx region of an idealised human extra-thoracic airway obtained using particle image velocimetry (PIV). The inlet velocity was 0.13?m/s yielding a Reynolds number, based on the inlet condition, of 670. Two thousand images were acquired at each location at a framing rate of 2?Hz. The proper orthogonal decomposition method was applied to the PIV data. Only a few modes were used for POD reconstruction which recovered about 60?% of the turbulent kinetic energy. A vortex identification algorithm was employed to identify and measure properties of the structures. This step was followed by a statistical analysis of the distribution of number, size, and strength of these vortices. The results reveal the formation of a large number of structures identified along two planes in the pharynx/larynx region. This study also revealed an increased strength in the counter-clockwise structures as compared to clockwise structures in the pharynx region. As well, there is some evidence to suggest that the vortical structures, whose axes are perpendicular to the sagittal plane, change their orientation as they proceed further into the laryngeal region.     

Determination of non-toxic and potentially toxic elements concentration and antioxidant capacity in selected natural and essential oils with high market values

Natural oils (NOs) and essential oils (EOs) are widely used in the food and beverage, medical, aromatherapy and cosmetic industries, but little is known about their elemental composition or antioxidant ability. Microwave-assisted acid digestion and inductively coupled plasma-optical emission spectroscopy were used to determine the non-toxic elements (Al, Ca, Cu, Fe, K, Mg, Na, Se and Zn) and potentially toxic elements (As, Cr, Cd, Mn, Ni and Pb) concentrations in 13 selected NOs and EOs. The per cent recoveries of laboratory-fortified blanks analysed for quality control were 94–110%. The elemental concentrations varied widely in NO and EO samples, as demonstrated by the large standard deviation obtained for some elements. The average levels of non-toxic elements (Al (14.5 ± 3.7 μg/g); Ca (278 ± 138 μg/g); Cu (7 ± 14 μg/g); Fe (16 ± 5 μg/g); K (36 ± 31 μg/g); Mg (56 ± 27 μg/g); Na (266 ± 277 μg/g); Se (0.7 ± 0.3 μg/g) and Zn (6.1 ± 2.6 μg/g)) were determined in NOs and EOs. Comparatively, low levels of potentially toxic elements (As (0.1 ± 0.2 μg/g); Cd (0.1 ± 0.0 μg/g); Cr (0.2 ± 0.1 μg/g); Mn (0.8 ± 0.1 μg/g); Ni (4.5 ± 2.2 μg/g); and Pb (0.3 ± 0.2 μg/g)) were obtained in the oils. Principal component analysis (PCA) revealed that the first two principal components explained 100% of the variability in the elemental concentrations. Na, Ca, Mg and K were the main contributors to PCA. Non-toxic element pairs were strongly correlated (R² > 0.9440) indicating a common source in these oils, but toxic element pairs were poorly correlated. Although toxic element concentrations were low, routine monitoring in oils is recommended. The antioxidant ability of NOs and EOs to potentially reduce free radicals, which are often involved in several degenerative diseases, such as ageing, stroke, diabetes and cancers was determined by DPPH (2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl) free radical scavenging assay and ultraviolet-visible spectroscopy. Jasmine, castor and tea tree lemon oils were the best antioxidants. The oils in this study have the potential to replace artificial antioxidants used in foods, cosmetics and other products.     

Enantioselective, biocatalytic reduction of 3-substituted cyclopentenones: application to the asymmetric synthesis of an hNK-1 receptor antagonist

A convergent and enantioselective route to the hNK-1 receptor antagonist (1) is described, which sets all six stereogenic centers with high diastereoselectivity and delivers 1 in only 11 steps and 23% overall yield. The process was enabled by the development of the enantioselective enzymatic reduction of 3-functionalized cyclopentenones and stereospecific Pd-catalyzed etherification coupling of fragments 6 and 7.     

Quantification of branched-chain amino acids in blood spots and plasma by liquid chromatography tandem mass spectrometry for the diagnosis of maple syrup urine disease

Individuals with maple syrup urine disease (MSUD) have an inherited metabolic disorder resulting in a deficiency in the branched-chain keto-acid dehydrogenase complex. As a result, these individuals have elevated concentrations of the branched-chain amino acids valine, isoluecine, allo-isoleucine, and leucine. MSUD presents in the first few days of life and progression may lead to irreversible intellectual disability, coma, cerebral edema, and death. However, early diagnosis and intervention can mitigate or eliminate many of the potential adverse effects. Consequently, it is important to develop techniques to screen for MSUD. We have developed an LC-MS/MS assay for the diagnosis of MSUD. The method is amenable to high-throughput formats due to the minimal sample prep required. The assay was shown to be robust, precise, and accurate. Finally, we identified and addressed some of the problems associated with working with bloodspots and implemented satisfactory approaches to overcoming these problems.     

Flux line lattice symmetries in the borocarbide superconductor LuNi2B2C

We compare the results of small angle neutron scattering on the flux line lattice (FLL) obtained in the borocarbide superconductor LuNi₂B₂C with the applied field along the c- and a-axes. For H‖c the temperature dependence of the FLL structural phase transition from square to hexagonal symmetry was investigated. Above 10 K the transition onset field. H ₂(T), rises sharply, bending away from H _c2(T) in contradiction to theoretical predictions of the two merging. For H‖a a first order FLL reorientation transition is observed at H _tr=3–3.5 kOe. Below H _tr the FLL nearest neighbor direction is parallel to the b-axis, and above H _tr to the c-axis. This transition cannot be explained using nonlocal corrections to the London model.     

Azo dyes from 2-amino-1,3,4-thiodiazole

Thiodiazolyazo dyes from resorcinol, p-cresol and beta-naphthol have been prepared. They are inferior to their thiazole and triazole analogues in their colour-forming reactions with metal ions.     

Rotational reorganization of doped cholesteric liquid crystalline films

In this paper an unprecedented rotational reorganization of cholesteric liquid crystalline films is described. This rotational reorganization results from the conversion of a chiral molecular motor dopant to an isomer with a different helical twisting power, leading to a change in the cholesteric pitch. The direction of this reorganization is correlated to the sign of the change in helical twisting power of the dopant. The rotational reorganization of the liquid crystalline film was used to rotate microscopic objects 4 orders of magnitude larger than the bistable dopants in the film, which shows that molecular motors and switches can perform work. The surface of the doped cholesteric liquid crystalline films was found to possess a regular surface relief, whose periodicity coincides with typical cholesteric polygonal line textures. These surface features originate from the cholesteric superstructure in the liquid crystalline film, which in turn is the result of the presence of the chiral dopant. As such, the presence of the dopant is expressed in these distinct surface structures. A possible mechanism at the origin of the rotational reorganization of liquid crystalline films and the cholesteric surface relief is discussed.     

INDUCED REPAIR IN ESCHERICHIA COLI: INDUCTION BY ULTRAVIOLET LIGHT AT-79°C

Two of the phenomena associated with induced (S.O.S.) repair, namely induced inhibition of post radiation DNA degradation and induced radioresistance have been shown to be elicited by 245 nm radiation applied to E. coli cells in the frozen state at -79°C. The effect of radiation in this condition is considerably less photoreactivable than similar effects produced by exposure in the wet state. Since protein-DNA crosslinks are believed to be formed under these conditions, such consequences of UV radiation appear to be a potent inducer of induced repair.     

Counterion-dependent excitonic spectra of tetra(p-carboxyphenyl)porphyrin aggregates in acidic aqueous solution

Aggregates of the diacid form of tetra(p-carboxyphenyl)porphyrin (TCPP) are found to be stabilized in aqueous solution at low pH in the presence of poly(vinyl alcohol). At pH values in the range from about 1 to 4, a split Soret band is observed which is independent of counterion and tentatively assigned to a dimer species. As the pH is made lower than 1, the spectra evolve to reveal the presence of porphyrin aggregates. As in the case of the well-known aggregates of the related tetra(p-sulfonatophenyl)porphyrin (TSPP) diacid, the concentration of spectroscopically distinguishable aggregates increases with increasing ionic strength or decreasing pH. Unlike aggregates of TSPP, however, TCPP aggregates below pH 1 have visible absorption spectra which depend on the counterion, which is Cl(-) or NO(3)(-) in this study. In this work, we present visible absorption, light-scattering, and resonance Raman spectra of TCPP diacid in its monomer, dimer, and aggregated forms and attempt to understand the structural basis for counterion-dependent structure and excitonic coupling in the aggregates. Evidence is presented for intercalation of inorganic counterions between porphyrin molecules in the aggregate, an effect which to our knowledge has not been previously reported.     

Synthesis of 2-substituted-5-rnethylthiazolo[ 3,2-b ] -1,2,4-lriazoles and acylatcd 3-amino-2-imino-4-methyl-2-thiazolines

3-Amino-2-imino-4-mcthyl-2-thiazoline, 1, underwent ring closure with ethyl formate, cyanogen bromide and carbon disulfide, giving moderate yields of 2-substituted-5-methylthiazolo[ 3,2-b ]-1,2,4-triazoles, II. Reaction of I-HCl with acid anhydrides (acetic, propionie, trifluoroacetic) resulted in the formation of the corresponding II compounds, whereas other anhydrides (benzoic, perfluoropropionic, perfluorobutyric) gave high yields of 3-aeylamido-2-acylimido-4-melhyl-2-thiazolines. With acid chlorides and I-HCl, in the presence of trielhylamine, mixtures of 2-acyl-irnino-3-aniino-4-methyl-2-thiazolines and 2-aeylimino-3-(diacylamido)-4-methyl-2-thiazolines are formed. Spectral characteristics are reported.