Dünnschicht-chromatographischer Nachweis herbicider Verbindungen durch Dansylierung

The reaction of dansyl chloride with various herbicides and derivatives containing amino groups or hydrolyzable to anilines is described. On TLC plates the fluorescent substances can be readily separated and identified as shown by diagrammatic representation of the thin-layer chromatograms.     

Modeling the role of nonhuman vocal membranes in phonation

Although the mammalian larynx exhibits little structural variation compared to sound-producing organs in other taxa (birds or insects), there are some morphological features which could lead to significant differences in acoustic functioning, such as air sacs and vocal membranes. The vocal membrane (or "vocal lip") is a thin upward extension of the vocal fold that is present in many bat and primate species. The vocal membrane was modeled as an additional geometrical element in a two-mass model of the larynx. It was found that vocal membranes of an optimal angle and length can substantially lower the subglottal pressure at which phonation is supported, thus increasing vocal efficiency, and that this effect is most pronounced at high frequencies. The implications of this finding are discussed for animals such as bats and primates which are able to produce loud, high-pitched calls. Modeling efforts such as this provide guidance for future empirical investigations of vocal membrane structure and function, can provide insight into the mechanisms of animal communication, and could potentially lead to better understanding of human clinical disorders such as sulcus vocalis.     

Irregular vocal-fold vibration--high-speed observation and modeling

Direct observations of nonstationary asymmetric vocal-fold oscillations are reported. Complex time series of the left and the right vocal-fold vibrations are extracted from digital high-speed image sequences separately. The dynamics of the corresponding high-speed glottograms reveals transitions between low-dimensional attractors such as subharmonic and quasiperiodic oscillations. The spectral components of either oscillation are given by positive linear combinations of two fundamental frequencies. Their ratio is determined from the high-speed sequences and is used as a parameter of laryngeal asymmetry in model calculations. The parameters of a simplified asymmetric two-mass model of the larynx are preset by using experimental data. Its bifurcation structure is explored in order to fit simulations to the observed time series. Appropriate parameter settings allow the reproduction of time series and differentiated amplitude contours with quantitative agreement. In particular, several phase-locked episodes ranging from 4:5 to 2:3 rhythms are generated realistically with the model.     

Advanced design of t and pH dual‐responsive PDEAEMA–PVCL core–shell nanogels for siRNA delivery

The synthesis, characterization, and potential application as gene delivery systems of biodegradable dual‐responsive core–shell nanogels based on poly(2‐diethylaminoethyl) methacrylate (PDEAEMA) and poly(N‐vinylcaprolactam) (PVCL) are reported. These core–shell nanogels, having a PDEAEMA‐based core and a PVCL‐based shell, were synthesized by batch seeded emulsion polymerization. An indepth study of their swelling behavior was carried out, which presented a dual‐dependent thermo‐ and pH sensitivity. Core–shell nanogels synthesized formed complexes spontaneously through electrostatic interactions when mixing with small interfering RNA (siRNA) molecules. Moreover, the core–shell nanogel/siRNA complexes showed higher polyanion exchange resistance compared to that of the PDEAEMA‐based nanogel/siRNA complexes, indicating that the PVCL‐based shell enhanced the stability of the complexes. In vitro siRNA release profiles showed that siRNA release was controlled by the pH of the medium as well as by the crosslinking density of the PVCL‐based shell. These results indicate that dual‐responsive core–shell nanogels synthesized could be potentially useful as gene delivery systems. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3203–3217     

A tandem C-H insertion—acetal cleavage sequence: stereocontrolled synthesis of substituted tetrahydrofurans

A short sequence involving Rh(II) mediated carbene insertion followed by Lewis acid promoted reductive acetal cleavage with Et₃SiH provides a stereoselective method for the construction of 2,3,5-trisubstituted tetrahydrofuran rings.     

Comparison of biomechanical modeling of register transitions and voice instabilities with excised larynx experiments

Voice instabilities were studied using excised human larynx experiments and biomechanical modeling. With a controlled elongation of the vocal folds, the experiments showed registers with chest-like and falsetto-like vibrations. Observed instabilities included abrupt jumps between the two registers exhibiting hysteresis, aphonic episodes, subharmonics, and chaos near the register transitions. In order to model these phenomena, a three-mass model was constructed by adding a third mass on top of the simplified two-mass model. Simulation studies showed that the three-mass model can vibrate in both chest-like and falsetto-like patterns. Variation of tension parameters which mimic activities of laryngeal muscles could induce transitions between both registers. For reduced prephonatory areas and damping constants, extended coexistence of chest and falsetto registers was found, in agreement with experimental data. Subharmonics and deterministic chaos were observed close to transitions between the registers. It is concluded that the abrupt changes between chest and falsetto registers can be understood as shifts in dominance of eigenmodes of the vocal folds.     

Down-conversion in the 4–18 μm range with GaSe and AgGaSe2 nonlinear crystals

The signal and idler outputs from a LiNbO₃ optical parametric oscillator have been down-converted in GaSe and AgGaSe₂ crystals. A many hundred watt peak power output continuously tunable in the range 4–18 μm has been achieved.     

Substitutionsprodukte des Cyclopentadiens, 11. Mitt.: Allylcyclopentadien und (x-Cyclopentadienyl)-allyl-palladium-Komplexe

Zusammenfassung Es wird über Synthese und Reaktionen des Allylcyclopentadiens (I) sowie (Allylcyclopentadienyl)-allyl-palladiums (VIII) und VIII-Analoger berichtet.Fortsetzung der 5. Mitt., Mh. Chem.91, 809 (1960).     

Delegated portfolio management under ambiguity aversion

We examine the problem of setting optimal incentives for a portfolio manager hired by an investor who wants to induce ambiguity–robust portfolio choices with respect to estimation errors in expected returns. Adopting a worst-case max–min approach we obtain the optimal compensation in various cases where the investor and the manager, adopt or relinquish an ambiguity averse attitude. We also provide examples of applications to real market data.     

Spatio-temporal analysis of irregular vocal fold oscillations: biphonation due to desynchronization of spatial modes.

This report is on direct observation and modal analysis of irregular spatio-temporal vibration patterns of vocal fold pathologies in vivo. The observed oscillation patterns are described quantitatively with multiline kymograms, spectral analysis, and spatio-temporal plots. The complex spatio-temporal vibration patterns are decomposed by empirical orthogonal functions into independent vibratory modes. It is shown quantitatively that biphonation can be induced either by left-right asymmetry or by desynchronized anterior-posterior vibratory modes, and the term "AP (anterior-posterior) biphonation" is introduced. The presented phonation examples show that for normal phonation the first two modes sufficiently explain the glottal dynamics. The spatio-temporal oscillation pattern associated with biphonation due to left-right asymmetry can be explained by the first three modes. Higher-order modes are required to describe the pattern for biphonation induced by anterior-posterior vibrations. Spatial irregularity is quantified by an entropy measure, which is significantly higher for irregular phonation than for normal phonation. Two asymmetry measures are introduced: the left-right asymmetry and the anterior-posterior asymmetry, as the ratios of the fundamental frequencies of left and right vocal fold and of anterior-posterior modes, respectively. These quantities clearly differentiate between left-right biphonation and anterior-posterior biphonation. This paper proposes methods to analyze quantitatively irregular vocal fold contour patterns in vivo and complements previous findings of desynchronization of vibration modes in computer modes and in in vitro experiments.