Therelationship between professional operatic soprano voice and high range spectral energy

Operatic sopranos need to be audible over an orchestra yet they are not considered to possess a singer's formant. As in other voice types, some singers are more successful than others at being heard and so this work investigated the frequency range of the singer's formant between 2000 and 4000 Hz to consider the question of extra energy in this range. Such energy would give an advantage over an orchestra, so the aims were to ascertain what levels of excess energy there might be and look at any relationship between extra energy levels and performance level. The voices of six operatic sopranos (national and international standard) were recorded performing vowel and song tasks and subsequently analyzed acoustically. Measures taken from vowel data were compared with song task data to assess the consistency of the approaches. Comparisons were also made with regard to two conditions of intended projection (maximal and comfortable), two song tasks (anthem and aria), two recording environments (studio and anechoic room), and between subjects. Ranking the singers from highest energy result to lowest showed the consistency of the results from both vowel and song methods and correlated reasonably well with the performance level of the subjects. The use of formant tuning is considered and examined.     

Novel imprinted soluble microgels with hydrolytic catalytic activity

The synthesis and kinetic characterisation of soluble imprinted acrylamide based microgels incorporating arginine and tyrosine derivatives as additional functional monomers is reported.     

Porphyrin-acetylene-thiophene polymer wires

5,15-Bis[acetylene-4-(ethylenedioxy)thiophene]-10,20-bis(4-carboxyphenyl)porphyrin was synthesized by a Sonogashira coupling and polymerized to fibres; TEM and AFM images show uniform porphyrin wires with a length of several micrometers and a thickness of less than 4 nm.     

Development of an accelerated low-pH reversed-phase liquid chromatography column stability test

The important experimental design criteria for an accelerated low-pH RPLC column stability test are discussed. The influence of method variables on the amount and rate of retention-loss and the final optimized parameters for the accelerated low-pH RPLC stability test are presented. The retention-loss curves for selected C8 and C18 stationary phases are compared. These studies indicate that ligand chain length, functionality and bonding density play an important role in determining the low-pH stability of a stationary phase. Additionally, elemental analysis data are used to infer the mechanism responsible for the observed retention-loss under low-pH conditions.     

Radial limits of interpolating Blaschke products

It is shown that if (_n) is a sequence of distinct points on the unit circle, then, for a sequence (a_n) of points in the closed unit disk, there exists an interpolating Blaschke product B with B*(_n)=a_n for all n if and only if (a_n) is bounded away from zero. This complements results of Cargo, Carroll, Colwell, Belna and Piranian on prescribing radial limits for Blaschke products.Mathematics Subject Classification (2000): 30D50Revised version: 1 June 2004Acknowledgment The authors thank the Mathematisches Forschungsinstitut Oberwolfach for the support and for the kind hospitality they always receive. The work presented here is part of their 2002–2004 project Inner functions. The first author also thanks Universität Bern where she spent her sabbatical, as well as Université de Metz, where she was professeur invité for one month. The second author presented this work in May 2004 at the fourth congress of the European network Analysis and Operators in Dalfsen, the Netherlands. He gratefully acknowledges the support he received from the European communitys human potential program, contract HPRN-CT-2000-00116.     

Rational design of alkylene-linked bis-pyridiniumaldoximes as improved acetylcholinesterase reactivators

To improve the potency of 2-pralidoxime (2-PAM) for treating organophosphate poisoning, we dimerized 2-PAM and its analogs according to Wilson's pioneering work and the 3D structure of human acetylcholinesterase (hAChE) inactivated by isoflurophate. 1,7-Heptylene-bis-N,N'-syn-2-pyridiniumaldoxime, the most potent of the alkylene-linked dimeric reactivators, was readily synthesized using bistriflate and is 100 times more potent than 2-PAM in reactivating hAChE poisoned by isoflurophate. Experimental and computational studies confirm that 2-PAM in its biologically active form adopts the syn-I configuration. Further, they suggest that the improved performance of dimeric oximes is conferred by two-site binding with one oxime pointing toward the diisopropyl ester at the catalytic site of hAChE and the other anchored at the peripheral site. This type of binding may induce a conformational change in the acyl pocket loop which modulates the catalytic site via a domino effect.     

Silicon-directed selective gamma substitution of an α,β-unsaturated ester

Ethyl 3-methyl-2-trimethylsilyl-3-butenoate ($\text{3}$) undergoes reaction selectively at carbon 4, upon treatment with a Lewis acid and carbonyl compounds, acetals/ketals, acid chlorides, and chloromethyl phenyl sulfide. This overall conversion represents a highly selective gamma substitution on an α,β-unsaturated ester.     

Approaches to the synthesis of 3-fluoroshikimic acids

Exploitation of the dual dehydrating and fluorodeoxygenating properties of the dialkylaminosulfurtrifluorides has allowed access to the C3-fluorinated analogues of (−)-shikimic acid.