Development of vocal tract length during early childhood: a magnetic resonance imaging study

Speech development in children is predicated partly on the growth and anatomic restructuring of the vocal tract. This study examines the growth pattern of the various hard and soft tissue vocal tract structures as visualized by magnetic resonance imaging (MRI), and assesses their relational growth with vocal tract length (VTL). Measurements on lip thickness, hard- and soft-palate length, tongue length, naso-oro-pharyngeal length, mandibular length and depth, and distance of the hyoid bone and larynx from the posterior nasal spine were used from 63 pediatric cases (ages birth to 6 years and 9 months) and 12 adults. Results indicate (a) ongoing growth of all oral and pharyngeal vocal tract structures with no sexual dimorphism, and a period of accelerated growth between birth and 18 months; (b) vocal tract structure's region (oral/anterior versus pharyngeal/posterior) and orientation (horizontal versus vertical) determine its growth pattern; and (c) the relational growth of the different structures with VTL changes with development-while the increase in VTL throughout development is predominantly due to growth of pharyngeal/posterior structures, VTL is also substantially affected by the growth of oral/anterior structures during the first 18 months of life. Findings provide normative data that can be used for modeling the development of the vocal tract.     

Die komplexometrische Bestimmung von Calcium und Magnesium in menschlichem Blutserum

Zusammenfassung Der Calciumgehalt im menschlichen Serum läßt sich durch Fällung als Oxalat und Titration des in Salzsäure gelösten Niederschlages mit ÄDTA und 2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoe-säure als Indikator bestimmen. Im Überstand des abzentrifugierten Oxalatniederschlages läßt sich das Magnesium mit ÄDTA und Eriochromschwarz T als Indikator titrieren.

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Summary The calcium content of human serum can be determined by precipitation as oxalate, and titration of the solution obtained by dissolving the precipitate in hydrochloric acid, with EDTA in the presence of 2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid as indicator. The magnesium can be determined in the supernatant liquid resulting from the centrifugation of oxalate precipitate; the titration is carried out with EDTA and eriochrome black T as indicator.

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Résumé On peut déterminer la teneur en calcium du sérum humain par précipitation à l'état d'oxalate et titrage du précipité dissous dans l'acide chlorhydrique par l'EDTA avec l'acide hydroxy-2 (hydroxy-2 sulfo-4 naphtylazo-1)-1 naphtoïque-3 comme indicateur. En séparant par centrifugation le précipité d'oxalate, on peut titrer le magnésium par l'EDTA avec le noir ériochrome T comme indicateur.

     

Effect of solute-co-ordinating solvent interactions and temperature on the EPR and electronic spectra of bis(dithiophosphato)copper(II)

The self-redox reaction proceeding between two molecules of the complex bis(disubstituted-dithiophosphato)copper(II), CuII(R2-dtp)2, is studied by EPR and UV-VIS spectroscopy in DMFA, DMSO and pyridine. The effect of temperature and disulphide concentration in the solutions is also evaluated. The EPR spectra show that the g-values of CuII(R2-dtp)2 increase when it is dissolved in co-ordinating solvents, whereas the copper hyperfine splitting decreases compared to the corresponding values in non-co-ordinating solvents. Under the same conditions, a hypsochromic shift is observed in the maximal absorption at 420 nm of the electronic spectra which corresponds to the ligand-to-metal charge-transfer (LMCT) transition of the complex. The results are explained with the formation of axial or equatorial adducts between CuII(R2-dtp)2 and the co-ordinating solvents used. On the other hand, the molar absorptivity of the LMCT band and the intensity of the EPR spectrum increase strongly with the nature of the used co-ordinating solvent, the time after dissolution and the quantity of added disulphide. Both also depend on the size and shape of remote ligand substituents and they increase in the order Me < Et < i-Pr. Beer's law is not obeyed immediately after dissolution of copper bis-dithiophosphate complexes. However, after standing for 24 h in the dark, DMFA solutions exhibit linear absorption/concentration dependence with approximately 70% higher molar absorptivity. An additional increase of the LMCT band and EPR intensity is found after heating the solution up to 50 degrees C for a short time, as well as after addition of the corresponding disulphide of dithiophosphate [(RO)2P(S)S-S(S)P(RO)2] to the CuII(R2-dtp)2 solution. As a result, the molar absorptivity value at the maximum of the LMCT band of Cu[(i-PrO)2-dtp]2 increases from 7.9 x 10(3) m(-1) dm3 cm(-1) immediately after dissolution to 2.9 x 10(4) m(-1) dm3 cm(-1). In DMSO and pyridine, the intensity of both the EPR signal and LMCT band of CuII(R2-dtp)2 continuously decrease after the preparation of the solutions. A small increase is only observed immediately after the addition of the corresponding disulphide of dithiophosphate. While DMFA forms stable adducts with Cu[(i-PrO)2-dtp]2, adduct formation with DMSO and pyridine destroys the initial complex.     

Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology

The photophysical properties of three new water‐soluble terrylenediimide (WS‐TDI) derivatives are investigated and their utilization in biological experiments is demonstrated. Each of these dyes can be excited in the far red region of the visible spectrum, making them good candidates for in‐vivo studies. Single‐molecule techniques characterize their photophysics that is, the number of emitted photons, blinking characteristics and survival times until photobleaching takes place. All three dyes exhibit bright fluorescence, as well as an extremely high resistance against photodegradation compared to other well‐known fluorophores. Due to their different characteristics the three new WS‐TDI derivatives are suitable for specialized biological applications. WS‐TDI dodecyl forms non‐fluorescent aggregates in water which can be disrupted in a hydrophobic environment leading to a monomeric fluorescent form. Due to its high lipophilicity WS‐TDI dodecyl anchors efficiently in lipid bilayers with its alkyl chain and hence can be ideally used to image membranes and membrane‐containing compartments in living cells. In contrast, the positively charged WS‐TDI pyridoxy is a new type of chromophore in the WS‐TDI family. It is fully solubilized in water forming fluorescent monomers and is successfully used to label the envelope of herpes simplex viruses. Finally, it is shown that a WS‐TDI derivative functionalized with N‐hydroxysuccinimide ester moiety (WS‐TDI/NHS ester) provides a versatile reactive dye molecule for the specific labelling of amino groups in biomolecules such as DNA.     

Solid-state tautomerism in 2-carboxyindan-1,3-dione

The structure of 2-carboxyindan-1,3-dione was investigated using a combination of quantum-chemical calculations and solid-state NMR and IR spectroscopy. Due to poor solubility of the compound in different solvents, no single crystals could be obtained. Two dimeric structures formed from the tautomers of 2-carboxyindan-1,3-dione are likely to coexist in the solid state. The dimers interconvert via intramolecular proton transfer in one of the tautomeric forms constituting the dimers. The energy barrier of the intramolecular proton transfer reaction is calculated as 5.82 kcal mol(-1) at the MP2/6-31++G level of theory.     

Phenolic compounds of mountain tea from the Balkans: LC/DAD/ESI/MSn profile and content

Twenty-one samples of Sideritis species (S. scardica, S. raeseri, S. taurica, S. syriaca and S. perfoliata) from various locations on the Balkan Peninsula were evaluated for their chemical constituents. Chemical analyses were focused on secondary metabolites, particularly phenolic compounds, which have several roles in the plant physiological processes and have demonstrated significant health beneficial effects. The occurrence of hydroxycinnamic acids, phenylethanoid glycosides and flavonoids has been investigated in taxonomically related taxa of the genus Sideritis. A systematic method for phenolic compounds identification was developed using tandem mass spectrometry coupled to high performance liquid chromatography with diode array detection. Scanning for precursor ions of commonly found phenolics in Sideritis species using LC/MS11 with an ion trap instrument permitted the specific determination of hydroxycinnamic acid derivatives, and phenylethanoid and flavonoid glycosides. Further characterization of each phenolic compound was performed using MS/MS product-ion analysis and common-neutral-loss analysis. This on-line technique allowed identification of three hydroxycinnamic acid derivatives, eight phenylethanoid glycosides, and twenty-four flavonoid glycosides. All the taxa analysed produced very similar phenolic patterns characterized by the presence of 5-caffeoylquinic acid, lavandulifolioside, verbascoside, hypolaetin 7-O-[6'-O-acetyl]-allosyl(1-->2)glucoside, apigenin 7-(4"-p-coumaroylglucoside), 4'-O-methylisoscutellarein 7-O-[6'-O-acetyl]-allosyl(1-->2)glucoside, and minor amounts of isoverbascoside, apigenin 7-O-allosyl(1-->2)glucoside, isoscutellarein 7-O-allosyl-(1-->2)-[6"-O-acetyl]-glucoside, hypolaetin 7-O-allosyl-(1-->2)-[6"-O-acetyl]-glucoside and 4'-O-methylhypolaetin 7-O-[6'-O-acetyl]-allosyl-(1-->2)-[6"-O-acetyl]-glucoside. These results show that the investigated species are systematically very closely related. Phenylethanoid glycosides and flavonoid acetylglycosides are dominant and constitute 90% of the total phenolic compounds compared with hydroxycinnamic acid and flavonoid 7-O-glycosides. Principal component analysis (PCA) was performed for the nature and content of the different compounds to be correlated to the particular Sideritis species and also to the locations.     

Sharply Dominating MV-Effect Algebras

Some open questions on Archimedean atomic MV-effect algebras are answered. Namely we prove that there are Archimedean atomic MV-effect algebras which are not sharply dominating. Equivalently, they don’t have a basic decomposition of elements. Moreover, if their set of sharp elements (their center) is a complete lattice then they need not be complete lattices. The existence of infinite orthogonal sums of their elements is discussed.     

Bias-dependent admittance in hybrid bilayer membranes

Artificial bilayer membranes provide a platform for bioelectronic devices based on their structural, sensing, and transport functions. In this letter, we report on the impedance response of an engineered membrane with a lower leaflet of octadecanethiol on gold and an outer leaflet of dioleoylphosphatidylcholine with the monomeric channel protein gramicidin. This hybrid bilayer exhibits an electrical response analogous to a solid-state diode: the admittance is very low (<10(-)(7) Omega(-)(1) cm(-)(2)) over a wide potential range but increases exponentially at negative potentials.     

Directed assembly of surface-supported bilayers with transmembrane helices

The lateral assembly of transmembrane (TM) helices gives rise to membrane proteins with complex folds, which play important roles in biochemical processes. Therefore, the assembly of surface-supported bilayers containing TM helices is the first step toward the development of functional biomembrane mimetics. Here we report novel directed assembly of surface-supported lipid bilayers with laterally mobile TM helices. The TM helices were incorporated into lipid monolayers at the air/water interface, and the monolayers were then transferred onto glass substrates using Langmuir-Blodgett (LB) deposition. Finally, bilayers were assembled using lipid vesicle fusion on top of the LB monolayers. The novelty is the incorporation of the peptides into the monolayer at the first step of bilayer assembly, which allows control over the peptide concentration and orientation. The transmembrane orientation of the peptides was confirmed using oriented circular dichroism (OCD), lateral mobility was assessed using fluorescence recovery after photobleaching (FRAP), and diffusion coefficients were determined using a novel boundary profile evolution (BPE) method. The described directed-assembly approach can be used to develop versatile bilayer platforms for studying membrane proteins interactions in native bilayer environments.