Relation between perceived voice register and flow glottogram parameters in males

The perception of modal and falsetto registers was analyzed in a material consisting of a total of 104 vowel sounds sung by 13 choir singers, 52 sung in modal register, and 52 in falsetto register. These vowel sounds were classified by 16 expert listeners in a forced choice test and the number of votes for modal was compared to the voice source parameters: (1) closed quotient (Q(closed)), (2) level difference between the two lowest source spectrum partials (H1-H2), (3) AC amplitude, (4) maximum flow declination rate (MFDR), and (5) normalized amplitude quotient (NAQ, AC amplitude/MFDR(*) fundamental frequency). Tones with a high value of Q(closed) and low values of H1-H2 and of NAQ were typically associated with high number of votes for modal register, and vice versa, Q(closed) showing the strongest correlation. Some singer subjects produced tones that could not be classified as either falsetto or modal register, suggesting that classification of registers is not always feasible.     

Mechanism of the Coupling of Diazonium to Single‐Walled Carbon Nanotubes and Its Consequences

On the tube : The coupling of diazonium ions onto single‐walled carbon nanotubes is shown to proceed through a radical chain reaction by kinetic analysis of the absorption peak drop (see picture). Radical species are also revealed by ESR. Metallic (m) nanotubes play a special catalytic role in the functionalization of semiconducting (sc) nanotubes.

     

When do water-insoluble polyion-surfactant ion complex salts "redissolve" by added excess surfactant?

The redissolution of water-insoluble polyion-surfactant ion complexes by added excess of surfactant has systematically been investigated in experimental and theoretical phase equilibrium studies. A number of stoichiometric polyion-surfactant ion "complex salts" were synthesized and they consisted of akyltrimethylammonium surfactant ions of two different alkyl chain lengths (C(12)TA(+) and C(16)TA(+)) combined with homopolyions of polyacrylate of two different lengths (PA(-)(25) and PA(-)(6000)) or copolyions of acrylate and the slightly hydrophobic nonionic comonomers N-isopropylacrylamide (PA(-)-co-NIPAM) or N,N-dimethylacrylamide (PA(-)-co-DAM). The complex salts were mixed with water and excess alkyltrimethylammonium surfactant with either bromide or acetate counterions (C(n)TABr or C(n)TAAc). Factors promoting efficient redissolution were (i) very short polyions, (ii) a large fraction of NIPAM or DAM comonomers, and (iii) acetate, rather than bromide, as the surfactant counterion. Added C(12)TAAc gave an efficient redissolution of C(12)TAPA(25) but virtually no redissolution of C(12)TAPA(6000). A very efficient redissolution by added C(12)TAAc was obtained for PA(-)-co-NIPAM with 82 mol % of NIPAM. The C(12)TAPA-co-NIPAM/C(12)TAAc/H(2)O ternary phase diagram closely resembled the corresponding diagram for the much-studied pair cationic hydroxyethyl cellulose-(sodium) dodecyl sulfate. The simple Flory-Huggins theory adopted for polyelectrolyte systems successfully reproduced the main features of the experimental phase diagrams for the homopolyion systems, including the effect of the surfactant counterion. The efficient redissolution found for certain copolyion systems was explained by the formation of soluble polyion-surfactant ion complexes carrying an excess of surfactant ions through an additional hydrophobic attraction.     

HIV fusion inhibitor peptide T-1249 is able to insert or adsorb to lipidic bilayers. Putative correlation with improved efficiency

T-1249 is a HIV fusion inhibitor peptide under clinical trials. Its interaction with biological membrane models (large unilamellar vesicles) was studied using fluorescence spectroscopy. A gp41 peptide that includes one of the hydrophobic terminals of T-1249 was also studied. Both peptides partition extensively to liquid-crystalline POPC (1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine) (DeltaG = -7.0 kcal/mol and -8.7 kcal/mol, for T-1249 and terminal peptide, respectively) and are located at the interface of the membrane. T-1249 is essentially in a random coil conformation in this lipidic medium, although a small alpha-helix contribution is present. When other lipid compositions are used (DPPC, POPG + POPC, and POPC + cholesterol) (DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and POPG (1-palmitoyl-2-oleyl-sn-glycero-3-[phospho-rac-(1-glycerol)), partition decreases, the most severe effect being the presence of cholesterol. Partition experiments and fluorescence resonance energy transfer analysis show that T-1249 adsorbs to cholesterol-rich membranes. The improved clinical efficiency of T-1249 relative to enfuvirtide (T20) may be related to its bigger partition coefficient and ability to adsorb to rigid lipidic areas on the cell surface, where most receptors are inserted. Moreover, adsorption to the sterol-rich viral membrane helps to increase the local concentration of the inhibitor peptide at the fusion site.     

Use of experimental design in the optimization of stir bar sorptive extraction for the determination of polybrominated diphenyl ethers in environmental matrices

Stir bar sorptive extraction and liquid desorption (LD) followed by large volume injection and capillary gas chromatography coupled to mass spectrometry (SBSE-LD-LVI-GC-MS), had been applied for the determination of ultra-traces of eleven polybrominated diphenylethers (PBDEs), from tetra to nona congeners (BDE-47, BDE-100, BDE-99, BDE-85, BDE-154, BDE-153, BDE-183, BDE-197, BDE-196, BDE-207 and BDE-206), in environmental matrices. Instrumental calibration under the selected-ion monitoring (SIM) mode acquisition and parameters that could affect the SBSE-LD efficiency are fully discussed. A complete randomized factorial design was established for the first time to optimize the main experimental parameters that affecting the SBSE-LD efficiency, including decisive interactions, which provides a more realistic picture of the sampling process. The analysis of variance (ANOVA) was the statistical method used to analyze data. From the data obtained, it can be emphasized that experimental parameters such as extraction time (240 min), agitation speed (1250 rpm), methanol content (40%) and desorption conditions (acetonitrile, 15 min), were the best analytical compromise for the simultaneous determination between tetra and nona congeners in aqueous media. A remarkable recovery (65.6-116.9%) and repeatability (<12.1%) were attained, whilst the experimental data allowed very good agreement with predict theoretical equilibrium described by the octanol-water partition coefficients (K(PDMS/W) approximately = K(O/W)), with the exception of nona congeners since slightly lower yields were measured. Furthermore, excellent linear dynamic ranges from 0.01 to 14.0 microg/L (r2>0.9917) and low detection limits (0.3-203.4 ng/L) were also achieved for the eleven congeners studied. The proposed methodology was applied for the determination of ultra-trace levels of PBDEs in waste water, sediments and printed board circuit matrices by the standard addition approach, showing to be reliable, sensitive and having a low sample amount requirement in compliance with the international regulatory bodies.     

Highly Enantioselective Iridium‐Catalyzed Hydrogenation of Cyclic Enamides

The MaxPHOX–Ir catalyst system provided the highest selectivity ever reported for the reduction of cyclic enamides derived from α‐ and β‐tetralones. This result indicates that iridium catalysts are also proficient in reducing alkenes bearing metal‐coordinating groups. In the present system, selectivity was pressure‐dependent: In most cases, a decrease in the H₂ pressure to 3 bar resulted in an increase in enantioselectivity. Moreover, the process can be carried out in environmentally friendly solvents, such as methanol and ethyl acetate, with no loss of selectivity.     

High Final Energy of Low‐Level Gallium Arsenide Laser Therapy Enhances Skeletal Muscle Recovery without a Positive Effect on Collagen Remodeling

The aim of this study was to evaluate the effects of a Gallium Arsenide (GaAs) laser, using a high final energy of 4.8 J, during muscle regeneration after cryoinjury. Thirty Wistar rats were divided into three groups: Control (C, n = 10); Injured (I, n = 10) and Injured and laser treated (Injured/LLLT, n = 10). The cryoinjury was induced in the central region of the tibialis anterior muscle (TA). The applications of the laser (904 nm, 50 mW average power) were initiated 24 h after injury, at energy density of 69 J cm^?1 for 48 s, for 5 days, to two points of the lesion. Twenty‐four hours after the final application, the TA muscle was removed and frozen in liquid nitrogen to assess the general muscle morphology and the gene expression of TNF‐α, TGF‐β, MyoD, and Myogenin. The Injured/LLLT group presented a higher number of regenerating fibers and fewer degenerating fibers (P < 0.05) without changes in the collagen remodeling. In addition, the Injured/LLLT group presented a significant decrease in the expression of TNF‐α and myogenin compared to the injured group (P < 0.05). The results suggest that the GaAs laser, using a high final energy after cryoinjury, promotes muscle recovery without changing the collagen remodeling in the muscle extracellular matrix.     

2-Amino-3,4-diethylpyrrole derivatives: new building blocks for coiled structures

The synthesis of a multicomponent, mixed oligomer containing alpha-aminopyrrole is described; this system adopts a coiled structure in the solid state and serves as a prototype of a possible new class of hydrogen bond based helicates.     

Peripheral Arylation of Subporphyrazines

Peripherally hexaarylated subporphyrazines (SubPzs) have been prepared through a Pd‐catalyzed, CuTC‐mediated coupling of a hexaethylsulfanylated subporphyrazine with arylboronic acids. The introduced aryl substituents strongly influence the electronic properties of the subporphyrazine through effective conjugative interaction. Aryl rings endowed with π‐electron‐donating groups at the para positions produce a remarkable perturbation of the electron density of the SubPz macrocycle. This is reflected through significant redshifts of the SubPz CT and Q‐bands, together with increase of the molar absorptivity of the former, with respect to those exhibited by the hexaphenyl‐SubPz 2 a . Moreover, the trend in the first SubPz reduction potentials correlates with the Hammett constants (σ_p) corresponding to the para substituents of the aryl. The domed, extended SubPz π‐system self‐assembles in the solid state to form a dimeric capsule that houses a solvent molecule.