Using the theoretical linear energy solvation energy relationship to correlate and predict nasal pungency thresholds

The theoretical linear solvation energy relationship (TLSER) has been used to correlate and characterize 44 nasal pungency threshold (NPT) values in man with parameters derived from semi-empirical molecular orbital theory. The resulting relationship provides good correlative (R2 > 0.92) and predictive (R2cy > 0.88) capability. In addition, the TLSER parameters are used as a molecular probe to attempt to understand the fundamental properties influencing nasal pungency.     

Congenital melanocytic nevi and DNA content. An analysis by flow and image cytometry

BACKGROUND: Potential risk factors for the development of melanoma in congenital melanocytic nevi (CMN) are not well established. DNA aneuploidy may constitute such a risk factor but has not been sufficiently studied in CMN. METHODS: In the present study, DNA analysis of eight giant CMN, nine medium CMN (1.5-20 cm), and eight small CMN (< 1.5 cm) was assessed by flow cytometry and selected lesions (six nevi) by DNA image cytometry. DNA content was correlated with patient age, nevus size, and degree of cytologic atypia. RESULTS: DNA aneuploidy was detected by flow cytometry in two giant CMN from adult patients and in a small CMN from a child. DNA aneuploidy was not observed in any of the six CMN studied by image cytometry, although an increased S-phase was noted in a markedly atypical giant CMN. No DNA aneuploidy was detected in medium-sized CMN or in the CMN of nine patients 1 year of age or younger. CONCLUSION: In contrast to previous studies, it was observed that abnormal DNA content does tend to correlate with cytologic atypia, particularly in giant CMN with atypia or melanoma, in adults. Conversely, frank DNA aneuploidy in any CMN in children younger than 1 year of age, irrespective of histologic findings, was not detected. Finally, based on these limited studies, greater sensitivity of image over flow cytometry for detection of DNA aneuploidy cannot be verified.     

Serologic diagnosis of HIV (1988-1989)

Determination of antibodies to HIV virus by the ELISA technique was performed in 27,652 serum samples from January 1988 to November 1989. Samples which were positive twice underwent the Western Blot technique. A 0.41% of positiveness to the virus was found in 1988 and a 0.34% in 1989. Confirmation of positive cases by Western Blot was statistically significant in 1989.     

Comparative Study of the Influence of Homogeneous and Heterogeneous (Multi‐Phase) Precipitation Processes on the Particle Size Distribution

A Plexiglas vessel of a 0.30 m diameter filled with a diluted barium chloride solution and mixed by bubbling of an inert gas is used to model an industrial process. Solid sodium sulfate or sodium sulfate solution are added into the reactor to provoke the precipitation of barium sulfate. Two precipitation models, homogeneous and heterogeneous, are proposed. Especially, the heterogeneous precipitation model (much more complex than the homogeneous one) takes into account all elementary phenomena such as the dissolution of the solid phase, the nucleation in the liquid‐solid boundary layer and the nucleation and crystal growth in the bulk of liquid phase. Both models well predict the precipitate mean particle sizes. The decrease of the particle size in the case of the heterogeneous process is due to higher nucleation rate compared to the homogeneous process because of higher values of the sodium sulfate concentration in the boundary layer than those existing in the bulk.     

D-optimal designs

Many classical symmetrical designs have desirable characteristics, one of which is called D-optimality. The D-optimality concept can also be applied to select a design when the classical symmetrical designs cannot be used, such as when the experimental region is not regular in shape, when the number of experiments chosen by a classical design is too large or when one wants to apply models that deviate from the usual first or second order ones. The D-optimality concept is developed and it is also explained that D-optimality is only one possible criterion to choose a particular design. A few other criteria are also given that complement the information obtained by the D-criterion.     

Paal–Knorr synthesis of pyrroles: from conventional to green synthesis

The pyrrole molecular framework is found in a large number of natural and synthetic compounds of great importance. Since functionalized pyrroles are essential for the progress of many branches of science, its synthesis by simple, efficient and eco-friendly routes are particularly attractive in modern organic and bio-organic chemistry. To this end, a number of synthetic methods have been developed, in which the Paal–Knorr pyrrole synthesis stands out to be the easiest route to synthesize pyrroles. In spite of the efficiency, Paal–Knorr synthesis of pyrroles is considered limited by harsh reaction conditions, such as prolonged heating in acid, which may degrade sensitive functionalities in many potential precursors. Through this route almost all dicarbonyls can be converted to their corresponding heterocycles and therefore it is a synthetically valued process. To address the adverse issues this reaction route has undergone numerous modifications recently and today it can be said that this reaction route is a prominent green route for the synthesis of pyrroles. This review is a tour from the evolution and application of this harsh synthetic route to the eco-friendly greener route developed for the synthesis of pyrroles.