Electron microscopy and tomography reveal that sodium 2-naphthalene sulfonate incorporated into perming solutions swells and tilts trichocyte intermediate filaments causing straightening of curly Japanese human hair.

OBJECTIVE: A new hair-care process has been specifically developed for the straightening of curved Japanese woman's hair . The process included sodium 2-naphthalene sulfonate (SNS) in the reduction and oxidation steps of a conventional perming process. Our objective was to develop an understanding of how this process caused hair straightening by measuring the changes to morphology and ultrastructure between untreated, conventionally permed and SNS permed hair. Untreated and SNS permed Merino wool fibres were used to confirm structural changes. METHODS: Japanese hair samples were measured for single-fibre curvature before and after perming treatments. A silver staining method was developed to stain hair fibres without changing fibre curvature so that transmission electron microscopy could be used to measure changes in the lateral dimensions of all structural components from the cellular to protein filament level. Electron tomography determined intermediate filament slopes and slope changes after SNS perming relative to the central longitudinal axis of the fibre. RESULTS: SNS perming was found to cause greater lateral swelling than conventional perming of: the paracortical cells of wool; the cuticle, the cuticular cell membrane complex and the macrofibrillar centre-to-centre distance of hair; and of the intermediate filaments in wool and hair. In curved hair, SNS perming caused the intermediate filaments of the helical macrofibrils to simultaneously swell and to tilt further, resulting in the slight longitudinal contraction of the macrofibrils. The overall swelling and tilting was greatest in the helical macrofibrils of Type B cortical cells predominately located in the convex fibre half. The presence of a higher percentage of helical macrofibrils in the convex fibre half than in the concave fibre half caused a contraction differential between the two halves leading to straighten of the curved fibre. A mechanical model was proposed to explain how SNS perming straightened curly hair. CONCLUSION: The effects of conventional and SNS perming on the morphological and ultrastructural components of curved Japanese hair and high-curl Merino wool fibres have given clear insights into understanding the mechanism of fibre curvature change.

OBJECTIF: Un nouveau procédé de soin des cheveux a été spécialement conçu pour lisser les cheveux ondulés des Japonaises[1]. Le procédé utilise le sulfonate de naphthalène-2 sodium (SNS) dans les étapes de réduction et d'oxydation du procédé conventionnel de permanente. Notre objectif était de comprendre la façon dont ce procédé induisait le lissage des cheveux en mesurant les différences de changement morphologique et ultrastructural entre les cheveux non traités et ceux soumis à une permanente conventionnelle et une permanente à base de SNS. Des fibres de laine de mérinos non traitées et soumises à une permanente à base de SNS ont été utilisées pour confirmer les changements structurels. MÉTHODES: Des échantillons de cheveux japonais ont été utilisés pour mesurer la courbure d'une fibre isolée avant et après le traitement de permanente. Une méthode de coloration argent a été mise au point pour colorer les fibres de cheveux sans changer la courbure des fibres afin de pouvoir utiliser la microscopie électronique en transmission pour mesurer les modifications des dimensions en largeur de tous les composants structurels du filament, de la cellule aux protéines. Une tomographie électronique a déterminé les pentes intermédiaires et les changements de pente des filaments après permanente à base de SNS par rapport à l'axe longitudinal central de la fibre. RÉSULTATS: On a constaté que la permanente à base de SNS induisait un gonflement en largeur plus important que la permanente classique des cellules paracorticales de la laine; de la cuticule, du complexe de la membrane cellulaire cuticulaire et de la distance centre à centre des macrofibrilles du cheveu; et des filaments intermédiaires dans la laine et les cheveux. Dans les cheveux ondulés, la permanente à base de SNS a provoqué à la fois un gonflement et une inclinaison des filaments intermédiaires des macrofibrilles hélicoïdales, entraînant une légère contraction longitudinale des macrofibrilles. Au total, le gonflement et l'inclinaison étaient plus importants dans les macrofibrilles hélicoïdales des cellules corticales de type B situées principalement dans la moitié convexe de la fibre. La présence d'un pourcentage plus élevé de macrofibrilles hélicoïdales dans la moitié convexe par rapport à la moitié concave de la fibre a entraîné une contraction différentielle entre les deux moitiés qui a entraîné le redressement de la fibre courbée. Un modèle mécanique a été proposé pour expliquer comment la permanente à base de SNS lissait les cheveux bouclés. CONCLUSION: Les effets de la permanente conventionnelle et à base de SNS sur les composants morphologiques et ultrastructuraux des cheveux japonais ondulés et des fibres de laine très frisés de mérinos ont permis de mieux comprendre le mécanisme du changement de courbure des fibres.

Luminescent visualization of latent fingerprints by direct reaction with a lanthanide shift reagent.

The utilization of the lanthanide shift reagent tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium (III) [Eu(fod)3] as a simple one-step reagent for the luminescent visualization of latent fingerprints has been investigated. UV excitation of Eu(fod)3-treated prints, achieved by using a hand-held UV lamp or a Polilight, results in an orange emission at 614 nm. Time-resolved imaging is not required for visualization. Visualization of latent fingerprints on paper under the conditions used, although good, was found to be inferior to that obtained by standard DFO (1,8-diazafluoren-9-one) treatment, whereas visualization of prints obtained on aluminum drink cans and galvanized iron proved superior to that obtained by Superglue/panacryl treatment. Eu(fod)3 treatment can also be used first without compromising subsequent ninhydrin or DFO treatment, making it a 'nothing-to-lose" reagent.

ABTS: a safe alternative to DAB for the enhancement of blood fingerprints.

The use of 2,2'-azino-di-[3-ethylbenzthiazolinesulfonate(6)] diammonium salt (ABTS) for the enhancement of fingerprints in blood has been investigated. Optimal pH conditions and H2O2 concentrations have been determined using UV/Vis spectroscopy. ABTS is an effective and safe noncarcinogenic (though more expensive) alternative to the presently used 3,3'-diaminobenzidine (DAB) for the development of blood fingerprints, especially on porous surfaces. The bright green color of the oxidized ABTS is an advantage on certain colored surfaces where the dark brown color of DAB does not stand out well from the background. Development with ABTS does not interfere with subsequent DAB treatment, making ABTS a "nothing-to-lose" reagent. ABTS can be used after ninhydrin treatment, but the reverse is not the case.

The response of the Intoxilyzer 5000 to five potential interfering substances.

A study was conducted of potential vapor phase interferents which could be present on human breath and also be capable of inducing a false-positive response for ethanol on the evidential infrared-based breath testing device, the Intoxilyzer-5000. This involved preparation and validation of a range of vapor standards, which were introduced to the instrument using a dynamic flow double-bubbler system. Potential interferents were chosen on the basis of both their infrared signatures and their general availability, and included toluene, m-xylene, o-xylene, methanol and isopropanol. All compounds tested were found to be capable of inducing false-positive readings for ethanol in a highly reproducible manner, as a result of which it has been possible to derive precise least-squares equations describing the ethanol readout expected for any given blood concentration of toluene, m-xylene, o-xylene, methanol and isopropanol. The likelihood of an interference compromising the integrity of the analysis is related to both the toxicological significance and prevalence of a given blood concentration of each solvent, and the point at which the instrumental interference light is triggered in each case.

The role of habitat shift in the evolution of lizard morphology: evidence from tropical Tropidurus.

We compared morphology of two geographically close populations of the tropical lizard Tropidurus hispidus to test the hypothesis that habitat structure influences the evolution of morphology and ecology at the population level. T. hispidus isolated on a rock outcrop surrounded by tropical forest use rock crevices for refuge and appear dorsoventrally compressed compared with those in open savanna. A principal components analysis revealed that the populations were differentially distributed along an axis representing primarily three components of shape: body width, body height, and hind-leg length. Morphological divergence was supported by a principal components analysis of size-free morphological variables. Mitochondrial DNA sequences of ATPase 6 indicate that these populations are closely related relative to other T. hispidus, the rock outcrop morphology and ecology are derived within T. hispidus, and morphological and ecological divergence has occurred more rapidly than genetic divergence. This suggests that natural selection can rapidly adjust morphology and ecology in response to a recent history of exposure to habitats differing in structure, a result heretofore implied from comparative studies among lizard species.

Declining amphibian populations: the problem of separating human impacts from natural fluctuations.

Reports of declining amphibian populations in many parts of the world are numerous, but supporting long-term census data are generally unavailable. Census data from 1979 to 1990 for three salamander species and one frog species at a breeding pond in South Carolina showed fluctuations of substantial magnitude in both the size of breeding populations and in recruitment of juveniles. Breeding population sizes exhibited no overall trend in three species and increased in the fourth. Recent droughts account satisfactorily for an increase in recruitment failures. These data illustrate that to distinguish between natural population fluctuations and declines with anthropogenic causes may require long-term studies.

A canadian medical team in ethiopia.

In February 1985, a Canadian medical relief team was established in a northern Ethiopia refugee camp. Volunteer physicians, nurses, and support staff have worked in the camp since February 1985. Their activities range from supervising intensive feeding programs, to controlling infections, to educating patients. About 300-400 patients visit the outpatient clinics daily. Malnutrition, vitamin A and B deficiencies, scurvy, rickets, gastroenteritis, malaria, leprosy, tuberculosis, pneumonia, trachoma and tetanus are commonly seen. The continuing presence of the medical team depends on donations and volunteer participation.

Pinworms (enterobius vermicularis).

Pinworm infestation (enterobiasis, syn. oxyuriasis), though not usually dangerous, remains one of the commonest parasitic infections seen by the family physician. Particularly prevalent in the pediatric age group, pinworms also infect adults; in both groups the commonest symptom is pruritus ani. Detailed descriptions of history, life cycle, and epidemiology are given. In addition to hygienic measures useful in treatment, the particulars of drug therapy are also outlined.

Predator-prey relationships among larval dragonflies, salamanders, and frogs.

Tadpoles of the barking tree frog, Hyla gratiosa, are abundant in spring and summer in some ponds and Carolina bays on the Savannah River Plant near Aiken, South Carolina. To determine how these tadpoles survive in the presence of predaceous salamander larvae, Ambystoma talpoideum, and larvae of an aeshnid dragonfly, Anax junius, we determined fields densities and sizes of the predators and the prey and conducted predation experiments in the laboratory. Tadpoles rapidly grow to a size not captured by Ambystoma, although Anax larvae can capture slightly larger tadpoles. Differing habitat preferences among the tadpoles and the two predator species probably aid in reducing predation pressure. Preliminary work indicates that the tadpoles may have an immobility response to an attack by a predator. In addition, the smallest, most vulnerable tadpoles have a distinctive color pattern which may function to disrupt the body outline and make them indiscernable to predators.