1H and 13C NMR signal assignments of some new N,N'-diacyl proflavine derivatives

The complete 1H and 13C NMR signal assignments of 23 new N,N'-diacyl proflavine derivatives were achieved using one- and two-dimensional experiments (DEPT, HMQC and HMBC).

Differentiation of heterocyclic regioisomers: a combined tandem mass spectrometry and computational study of N-acridin-4-ylbenzylamide and N-acridin-2-yl-benzylamide

Electrospray ionization (ESI) tandem mass spectrometry (MS/MS) has been used to differentiate two positional isomers of acridine derivatives, N-acridin-4-ylbenzylamide and N-acridin-2-ylbenzylamide. The study revealed that the isomeric ion structures produced by these heterocycles could be distinguished upon collision-induced dissociations (CID). In particular, the loss of a water molecule was shown to be a regiospecific reaction of the protonated N-acridin-4-ylbenzylamide, in which the location of the benzylamide substituent with respect to the acridinic nitrogen greatly assists proton migration by allowing the creation of intramolecular hydrogen bonds. To a lesser extent, the two isomers could also be distinguished by the difference in the abundance of the benzoyl cation in the MS/MS spectra of the [M+H]+ ions, as this ion is produced with a much higher rate from N-acridin-4-ylbenzylamide. Calculations based on quantum-mechanical models have been performed to evaluate the stability of the ion structures and to support mechanisms proposed for these two dissociation reactions.

Synthesis and antileishmanial activity of 6-mono-substituted and 3,6-di-substituted acridines obtained by acylation of proflavine

Two new series of diaminoacridinic derivatives obtained from proflavine and N-(6-amino-3-acridinyl)acetamide were synthesised and assessed for their cytotoxic and antileishmanial activities. Two compounds, N-[6-(acetylamino)-3-acridinyl]acetamide and N-[6-(benzoylamino)-3-acridinyl]benzamide demonstrated highly specific antileishmanial properties against the intracellular amastigote form of the parasite. Structure-activity relationships established that the antiproliferative activity against human cells was greatly enhanced by the presence of a benzoylamino group in 6-mono-substituted acridines, while the presence of two acetylamino or benzoylamino groups in 3,6-di-substituted acridines strongly increased the specificity of the molecules for Leishmania parasite, suggesting that symmetric conformations could preferentially interfere with Leishmania metabolism.

1H and 13C chemical shifts for acridines: Part XIX. N,N'-diacylproflavine derivatives

The 1H and 13C NMR resonances of 15 N,N'-diacylproflavines were assigned completely and unequivocally using a concerted application of one- and two-dimensional experiments (DEPT, gs-COSY, gs-HMQC and gs-HMBC).

3D behaviour of Frieden filters in confocal imaging

The three-dimensional (3D) focal behaviour of the super-resolving Frieden filters is investigated numerically. It is shown that, as the central bright spot is sharpened, super-giant secondary maximums are formed on the optic axis. These lobes are much higher that the well-known side-lobes inherent to spatial filtering that surround the restricted, utilisable field, whose characteristics in the meridional plane are depicted for various values of the space-bandwidth parameter and for various numbers of terms that compose the window function. The two-terms filter is found to present, for the first time to my knowledge, some axial apodizing properties. To be compatible with practical realisation, the use of this class of filters in a single- and two-photon confocally scanned system is discussed in terms of 3D super-resolution with an intentionally limited light-power loss. It is shown that these filters match particularly well with recently designed axial apodizers for the transmission-mode confocal scanning microscope and provide a 3D intensity point-spread volume reduction of variable amount as high as 37 percent. The filtering process is shown to vary significantly with the mode of operation.

Isolation and structure elucidation of a new thermal breakdown product of glucobrassicin, the parent indole glucosinolate

The thermal breakdown of glucobrassicin, the major natural indole glucosinolate present in cruciferous vegetables, has been studied. This study has been conducted using pure synthetic glucobrassicin instead of raw vegetable material to eliminate possible other sources (i.e., enzymatic or chemical) of degradation. After 1 h in aqueous solution at 100 degrees C, 10% of the original glucobrassicin is degraded and yields a unique degradation compound. This compound is described for the first time and has been identified as 2-(3'-indolylmethyl)glucobrassicin on the basis of data obtained by (1)H nuclear magnetic resonance spectroscopy as well as tandem mass spectrometric experiments carried out from positive and negative electrospray produced ions.

[The Edinburgh Postnatal Depression Scale: the validity of its Quebec version for a population low socioeconomic status mothers]

This paper investigates the construct validity and reliability of a Quebec version of the Edinburgh Postnatal Depression Scale (EPDS) for a population of low-socioeconomic-status mothers. This scale was constructed for the specific purpose of measuring mothers' symptoms of depression during the postnatal period in an effort to alleviate the validity problems that could arise from depression scales intended for the general population. Two hundred and twenty-four mothers participating in a Quebec prevention program, "Naître égaux, grandir en santé" (Martin & Boyer, 1995) filled out the EPDS between the 22nd and the 35th day postpartum. A confirmatory factor analysis, conducted with LISREL, gives a 2-factor structure for the EPDS, the first representing symptoms of depression and the second symptoms of anxiety. This structure differs from the one presented by Cox, Holden, and Sagovsky (1987), authors of the EPDS. It corresponds, however to the results of other authors who looked at the EPDS with confirmatory factor analysis (Pop, Komproe, & van Son, 1992) and indicates a good construct validity. The reliability of the scale also appears satisfactory, with a Cronbach alpha co-efficient of 0.82.

Shock-wave-assisted ultrafast soliton generation

It is predicted numerically that soliton generation by four-wave mixing when the central wavelength of the initial pulse is below the zero-dispersion point of a nonlinear waveguide can be significantly boosted by shock-wave formation that reduces the launching power and extends the efficiency of that process deep inside the normal-dispersion region. Experimental evidence of the validity of this prediction is provided by spectral phase and intensity measurement of the propagated bound-state pulse.

[Recruitment of Montreal women of very low socioeconomic status for a randomized clinical study]

Studies show that it is difficult to recruit women of low socioeconomic status as clinical research participants. Such an objective was attained though as our results demonstrate in an evaluative study of a program implemented to lower the percentage of low birthweight in four CLSCs of the Island of Montreal between 1994 and 1996. The global recruitment strategy enabled us to reach 56.2% of our goal in 1994 and 77.4% in 1996. Two conclusions can be drawn from this result: the effectiveness of the three methods of recruitment varied according to each participating CLSC, and the global strategy, combined with the mobilization of community resources, was successful in enrolling women of low socioeconomic status.

[Recruitment of Montreal women of very low socioeconomic status for a randomized clinical study]

Studies show that it is difficult to recruit women of low socioeconomic status as clinical research participants. Such an objective was attained though as our results demonstrate in an evaluative study of a program implemented to lower the percentage of low birthweight in four CLSCs of the Island of Montreal between 1994 and 1996. The global recruitment strategy enabled us to reach 56.2% of our goal in 1994 and 77.4% in 1996. Two conclusions can be drawn from this result: the effectiveness of the three methods of recruitment varied according to each participating CLSC, and the global strategy, combined with the mobilization of community resources, was successful in enrolling women of low socioeconomic status.

An evaluation of psychometric properties of the client's questionnaire of the Wisconsin Quality of Life Index-Canadian version (CaW-QLI)

Psychometric properties of Client's questionnaire from the Canadian version of the Wisconsin Quality of Life-Index (CaW-QLI) were assessed with two groups, 89 English (E) and 94 French (F) individuals with schizophrenia or schizoaffective disorder. Sub-samples of 40 E and 36 F were re-interviewed within a 2-week period. Spearman correlations-SC between each domain and CaW-QLI global Score ranged from 0.39 to 0.76, while interdomain correlations were low, confirming the multi-dimensional properties of the scale. Cronbach's alpha (internal consistency) were 0.78 (E) and 0.70 (F) for the CaW-QLI global scores and, from 0.45 to 0.88 among seven of eight domains. Test-retest (Concordance Correlation Coefficient--CCC) ranged from 0.36 to 0.80 among the domains, and from 0.80 (E) and 0.85 (F) between CaW-QLI global scores. Regarding convergent validity, SC between CaW-QLI global score and Spitzer's QOL-Index were 0.72 (E) and 0.58 (F). As hypothesized, there were higher correlations between CaW-QLI global scores (E and F) and SF-36 scales related to mental health than those related to physical health. Minor changes in the scoring are proposed to enhance face and content validity.

High-power femtosecond-pulse reshaping near the zero-dispersion wavelength of an optical fiber

Nonlinear propagation of high-power femtosecond pulses close to the zero-dispersion wavelength of a singlemode optical fiber is studied experimentally and numerically. The roles of four-photon mixing, stimulated Raman scattering, and self-steepening in this process are represented through different extensions of the nonlinear Schrödinger equation.