Distortion-product otoacoustic-emission suppression tuning in human infants and adults using absorbed sound power

The greatest difference in distortion product otoacoustic emission (DPOAE) suppression tuning curves (STCs) in infant and adult ears occurs at a stimulus frequency of 6 kHz. These infant and adult STCs are much more similar when constructed using the absorbed power level of the stimulus and suppressor tones rather than using sound pressure level. This procedure incorporates age-related differences in forward and reverse transmission of sound power through the ear canal and middle ear. These results support the theory that the cochlear mechanics underlying DPOAE suppression are substantially mature in full-term infants.     

Histological and histochemical effects after occlusion alteration in suprahyoid muscles

This study verified the effect of unilateral teeth extraction on the suprahyoid muscles in gerbils (Meriones unguiculatus). Ten adult male gerbils weighing about 50g had induced occlusal alterations by upper molar teeth extraction on the left side while the other ten animals were only subjected to surgical stress, control group. After 60 days, animals of both groups, experimental and control had the suprahyoid muscles removed and processed for histological and histochemical (adenosine triphosphatase (ATPase), nicotine adenine dinucleotide tetrazolium reductase (NADH-TR) and succinate dehydrogenase (SDH)) purposes. The fiber type area was estimated in % according to Weibel method (point-counting method) using a test-system. The myosinic ATPase pH 4.7 activity in the control group of the digastric, milohyoid and geniohyoid muscles presented a small area of type I fiber and a larger area of type IIa fibers; in the experimental group, significant contractile capacity alteration was not observed. Samples of the digastric, milohyoid and geniohyoid muscles, after SDH activity, showed a small area with high metabolic activity fibers, and a large area with intermediary and low metabolic activity fibers in the control group. The milohyoid muscle of the experimental group presented low metabolic fibers in a reduced area, in both sides, however without significant difference. In the experimental group, high metabolic fibers were observed on the left side in a reduced area in the geniohyoid muscle, but without statistical significance. Thus, the geniohyoid muscle did not change the metabolic activity after occlusal alteration. In conclusion, 60 days of unilateral malocclusion induced was able to alter the fibers oxidative activity of the suprahyoid muscles, however, it does not affect the contractile property of the fibers. The digastric muscle has adequate fibers to produce fast contraction and able to resist to fatigue in intermediate degrees, but became more fatigable after unilateral exodontia.     

A rigidity theorem for holomorphic generators on the Hilbert ball

We present a rigidity property of holomorphic generators on the open unit ball of a Hilbert space . Namely, if is the generator of a one-parameter continuous semigroup on such that for some boundary point , the admissible limit - , then vanishes identically on .

     

Kinetics and mechanism of the pyridinolysis of diaryl carbonates

The reactions of 4‐methylphenyl and 4‐chlorophenyl 4‐nitrophenyl carbonates ( 1 and 2 , respectively), phenyl, 4‐methylphenyl, 4‐chlorophenyl, and 4‐nitrophenyl 2,4‐dinitrophenyl carbonates ( 3 , 4 , 5 , and 6 , respectively), and bis(2,4‐dinitrophenyl) carbonate ( 7 ) with a series of pyridines are studied kinetically at 25.0 °C in 44 wt% ethanol–water and an ionic strength of 0.2 M (KCl). The reactions are followed spectrophotometrically and under excess amine pseudo‐first‐order rate coefficients (k_obs) are found. For all these reactions, plots of k_obs versus free amine concentration at constant pH are linear, the slope (k_N) being independent of pH. The Brønsted‐type plots (log k_N vs. pK_a of the conjugate acids of the pyridines) are all biphasic (linear portions at high and low pK_a and a curvature in between). These plots are in accordance with a stepwise mechanism, through a zwitterionic tetrahedral intermediate (T^±), and a change in the rate‐determining step from formation of T^± to its breakdown to products, as the pyridine basicity decreases. Also studied are the effects of the leaving, non‐leaving, and electrophilic groups of the substrate, and of the amine nature, on the value (value at the center of curvature of the Brønsted‐type plots). Copyright © 2008 John Wiley & Sons, Ltd.     

Activation of mononuclear bone marrow cells treated in vitro with a complex homeopathic medication

Canova is a Brazilian homeopathic medication with immunomodulatory properties, recommended for patients where the immune system is depressed. Previous studies demonstrated that Canova induces up-regulation in numbers of leukocytes. The bone marrow microenvironment is composed of growth factors, stromal cells, extracellular matrix and progenitor cells that differentiate into mature blood cells. We now report the effect of in vitro administration of the medication on the mononuclear differentiation of the bone marrow cell. Swiss mice femurs were dissected cleaned and the cells of the marrow were flushed. The cells were plated, treated or not, incubated for different times and processed for light, transmission and scanning electron, and confocal microscopy analysis. Bone marrow cells showed an enhanced proliferation in vitro in response to Canova medication and Canova plus M-CSF and an increase was also observed in the numbers of the cell niches and ring-shaped nuclei cells. Confocal and transmission and scanning electron microscopy showed the stages of monocyte maturation, with resting and activated cells. With Canova treatment there was a marked increase in cell size, which is mainly attributable to the augmented cytoplasm, an increase in the number of mitochondria, expansion of the RER and an enlarged Golgi. The response to Canova treatment indicates that it influences mononuclear differentiation and activation of bone marrow progenitor and stromal cells.     

Direct determination of P in biodiesel by high-resolution continuum source graphite furnace atomic absorption spectrometry

The direct determination of P in biodiesel by high-resolution continuum source graphite furnace atomic absorption spectrometry has been investigated. A slow drying stage proved to be essential for good repeatability. Optimization was performed by a D optimal planning. The atomization temperature and modifier composition were the most relevant parameters. Thus, using a mixture of Pd (30 μg) and Mg(NO₃)₂ (20 μg) as the modifier, previously deposited onto the platform of the graphite tube and dried, a five step drying stage, and pyrolysis and atomization temperatures of 1000 and 2700 °C, respectively, a limit of detection of 0.5 μg g^− 1 was obtained. The analysis of biodiesel of different origins confirmed that external calibration with organic P standard solutions, diluted in P-free biodiesel, could be used. In this way, excellent agreement between the found and expected results was observed in the analysis of an ANP interlaboratorial exercise sample.     

Coexistence of √3 ×√3 and quasi-linear phases of sulfur adsorbed (Θ = 1/3) on a gold (111) substrate

We analyze with the aid of density functional theory and molecular dynamics simulations the adsorption of sulfur (S) on a Au(111) surface at different temperatures with a variety of geometries. We have found a new superficial phase in which sulfur atoms form a quasi-linear chain with energies very close to the expected . The results suggest the coexistence of both configurations at T < 300 K. At high temperatures (T > 300 K) it was shown that the sulfur atoms have high mobility which allows their migration among different adsorption sites. At low temperatures, the mobility decreases and a thermal activation barrier of 25-30 meV can be estimated.     

A generalized ring homomorphisms equation

We deal with the functional equation $$af(xy) + bf(x)f(y) + cf(x+y) + df(x) + kf(y) = 0\quad\quad\quad\quad\quad\quad\quad(\ast)$$ yielding a joint generalization of equations that has been studied by Dhombres (Aequationes Math 35:186–212, 1988), H. Alzer (private communication) and Ger (Publ Math Debrecen 52:397–417, 1998; Rocznik Nauk-Dydakt Prace Mat 17:101–115, 2000). We are looking for solutions f of equation ${(\ast)}$ mapping a given unitary ring into an integral domain. We continue Dhombres’ studies with the emphasis given upon the dropping of the 2-divisibility assumption in the domain. Among others, our aim is to find suitable conditions under which a function f satisfying ${(\ast)}$ yields a homomorphism between the rings in question.     

The OH-initiated oxidation of 1,3-butadiene in the presence of O2 and NO: a photolytic route to study isomeric selective reactivity

We report the study of the isomeric selective OH-initiated oxidation of 1,3-butadiene in the presence of O2 and NO using the LP/LIF technique. The photolysis of monodeuterated 1-iodo-3-buten-2-ol provides only one of the possible OD-butadiene adducts, the minor addition channel product, simplifying the oxidation mechanism. We find, based on analysis of OD time-dependent traces that prompt rearrangement of initial beta-hydroxyalkyl radicals to alpha-hydroxyalkyl radicals occurs in agreement with RRKM/ME theoretical predictions. We report a rate constant of (3.3+/-1.0) x 10(-11) cm3 molecules(-1) s(-1) for deuterium abstraction from the alpha-hydroxyalkyl radical at 298 +/-2 K. Our approach demonstrates the feasibility of isomeric selective kinetic studies of the OH-initiated oxidation of unsaturated hydrocarbons.     

Highlights in oleuropein aglycone structure

Oleuropein hydrolysis products, obtained both by endogenous beta-glucosidase and almond commercial one, were investigated by classic methodologies and by 1HNMR experiments. We found that both presence and relative amount of the different compounds in the reaction mixture are stricly related to the used enzyme.