Changes in orcine muscle water characteristics during growth--an in vitro low-field NMR relaxation study

This study investigates the effects of developmental stage and muscle type on the mobility and distribution of water within skeletal muscles, using low-field (1)H-NMR transverse relaxation measurements in vitro on four different porcine muscles (M. longissimus dorsi, M. semitendinosus, M. biceps femoris, M. vastus intermedius) from a total of 48 pigs slaughtered at various weight classes between 25 kg and 150 kg. Principal component analysis (PCA) revealed effects of both slaughter weight and muscle type on the transverse relaxation decay. Independent of developmental stage and muscle type, distributed exponential analysis of the NMR T(2) relaxation data imparted the existence of three distinct water populations, T(2b), T(21), and T(22), with relaxation times of approximately 1-10, 45-120, and 200-500 ms, respectively. The most profound change during muscle growth was a shift toward faster relaxation in the intermediate time constant, T(21). It decreased by approx. 24% in all four muscle types during the period from 25 to 150 kg live weight. Determination of dry matter, fat, and protein content in the muscles showed that the changes in relaxation time of the intermediate time constant, T(21), during growth should be ascribed mainly to a change in protein content, as the protein content explained 77% of the variation in the T(21) time constant. Partial least squares (PLS) regression revealed validated correlations in the region of 0.58 to 0.77 between NMR transverse relaxation data and muscle development for all the four muscle types, which indicates that NMR relaxation measurements may be used in the prediction of muscle developmental stage.     

Engineering Aspects of Preparation of Nanocrystalline Particles in Microemulsions

Engineering aspects of the preparation of palladium nanoparticles in non-ionic w/o-microemulsions are examined. In order to achieve reproducible synthesis conditions a semi-batch reactor with a standardized design is used. Influences of the stirring rate and of different ways of concentration control on the product properties are observed. For reproducible synthesis it is important to establish appropriate and defined preparation conditions. Monodisperse palladium particles of around 5nm size are obtained by adding the microemulsion containing the palladium salt at a constant feed rate to the precharged microemulsion containing the reducing agent. A quantitative kinetic model is proposed to describe particle formation in microemulsions. Unknown parameters of the model have been estimated by independent examinations or can be achieved by fitting to the experimental data.     

Approximations of open quotient and speed quotient from glottal airflow and egg waveforms : Effects of measurement criteria and sound pressure level

Noninvasive measures of vocal fold activity are useful for describingnormal and disordered voice production. Measures of open and speed quotient from glottal airflow and electroglottographic (EGG) waveforms have been used to describe timing events associated with vocal fold vibration. To date, there has been little consistency in the measurement criteria used to calculate quotient values. In this study, criteria of 20% and 50% were applied to the AC amplitude of glottal airflow and inverted EGG waveforms for measurement of open quotient. Criteria of 20%, 50%, and 80%, and a midslope criterion that segmented the waveform between 20% and 80% of the waveform amplitude, were used for the calculation of speed quotient. Subjects produced waveforms at sound pressure levels (SPL) of 70, 75, 80 and 85 dB. Results indicated that approximations of open quotient obtained from the glottal airflow waveform significantly decreased using both the 20% and 50% criteria as SPL increased from 80 to 85 dB. No significant changes were found in open quotient from the EGG waveform as a function of SPL. Results of speed quotient measures from the glottal airflow and EGG waveforms showed a generally increasing trend as SPL increased, although the differences were not statistically significant. The data suggest that the signal type, measurement criterion and SPL must be considered in interpreting quotient measures.     

Photometric method for the determination of nitrite in aqueous solutions and in blood

Summary The sensitivity of the hitherto known determinations of nitrite by formation of azo dyes and photometric measurement in aqueous solution is limited by the concentration of nitrite. In the method described here the azo compound formed is extracted into toluene and trichloroacetic acid is added to the extract. Immediately after addition of the latter the colour intensity reaches its maximum and is measured at 560 nm. In this way the sensitivity is made independent of the nitrite concentration in the aqueous solution and is limited only by the sample volume available.This study was supported by Deutsche Forschungsgemeinschaft.     

A linear algorithm for a core of a tree

A core of a graph G is a path P in G that is central with respect to the property of minimizing d(P) = Σ_υ?V(G)d(υ, P), where d(υ, P) is the distance from vertex υ to path P. We present a linear algorithm for finding a core of a tree. Since the core of a graph is not necessarily unique, we also output a list of all the vertices which are in some core.     

Reduction of β-ketosulfoxides : a highly efficient asymmetric synthesis of both enantiomers of methyl carbinols from the corresponding esters

It is shown that reductions of β-ketosulfoxides of identical chirality (R) at sulfur, lead to reduction products of opposite stereochemistry according to the reducing agent used. The high enantiomeric excesses obtained (80 to 100%) provide a general route to both enantiomers of methylcarbinols from the corresponding esters.     

Plexin B3 promotes neurite outgrowth,interacts homophilically,and interacts with Rin

Background  

Plexins, known to date as receptors of semaphorins, are implicated in semaphorin-mediated axon repulsion and growth cone collapse. However, subtype-specific functions of the majority of the nine members of the mammalian plexin family are largely unknown. In order to investigate functional properties of B-plexins, we analyzed the expression of human and murine plexin B3 and expressed full-length human plexins B2 (B2) and B3 (B3) in NIH-3T3 cells.     

Mass of the Bc meson in three-flavor lattice QCD

We use lattice QCD to predict the mass of the Bc meson. We use the MILC Collaboration's ensembles of lattice gauge fields, which have a quark sea with two flavors much lighter than a third. Our final result is mBc = 6304+/-12(+18)(-0) MeV. The first error bar is a sum in quadrature of statistical and systematic uncertainties, and the second is an estimate of heavy-quark discretization effects.     

Combining energetic and informational masking for speech identification

This study examined combinations of energetic and informational maskers in speech identification. Speech targets and maskers (speech or noise) were processed and filtered into sets of 15 narrow frequency bands. The target was the sum of eight randomly selected bands. More masking occurred for speech maskers than for spectrally matched noise maskers regardless of whether the masker bands overlapped the target bands. The greater effect of the speech maskers was interpreted as due to informational masking. When the masker was comprised of nonoverlapping bands of speech, the addition of bands of noise overlapping the speech masker, but not the speech target, reduced the overall amount of masking. Surprisingly, presenting the noise to the ear contralateral to the target and masker produced an even greater release from masking. The contralateral noise was apparently sufficient to cause a slight change in the image of the ipsilateral speech masker, possibly pulling it away from the target enough to allow the focus of attention on the target. This finding is consistent with the interpretation that in some conditions small binaural differences may be sufficient to cause, or significantly strengthen, the perceptual segregation of sounds.