Description of a scattering apparatus: application to the problems of characterization of opaque surfaces

We show how the complexity of a micropolished optical surface can be investigated in detail by measurement of the distribution of scattered light. We deal with problems of roughness anisotropy and uniformity together with cleaning problems. Experimental results concern numerous black glasses from different polishing shops and allow a determination of the polish inhomogeneity in a same glass set. After that, we present a detailed study of the apparatus function of the scatterometer, and we determine the limits of validity of our optical characterization method.

Epithelial differentiation of human skin equivalents after grafting onto nude mice

Human skin equivalents were developed in vitro with a unidimensionally retracted dermal equivalent made of human type I + III collagen and human MRC5 fibroblasts, and a multilayered epithelium grown in liquid medium from normal human keratinocytes in suspension. We investigated the degree of epidermal differentiation that could be achieved after in vivo grafting onto nude mice by means of light and electronmicroscopy as well as by immunohistochemistry. All transplanted grafts showed a primary take. The grafts formed an epidermis with a stratum corneum and from day 7 to 14 after transplantation a distribution of a 56.5 Kd keratin protein, involucrin, profilaggrin/filaggrin, and MHC-I antigens that was similar to what is noted in normal human epidermis. These data indicate that a full terminal differentiation was only achieved after in vivo transplantation of the cultured epithelium. Pigmentation was present, but no marker of Langerhans cells was seen at 4 weeks. Although there was no evidence of the dermal equivalent after 2 weeks, we noted a strong adherence of the graft to the wound bed, with the presence of type-IV collagen, laminin, and bullous pemphigoid antigen at the dermo-epidermal junction (day 7) and hemidesmosomes, a lamina lucida and a lamina densa (day 30). No epithelial damage was noted in spite of an inflammatory infiltrate in the underlying tissue. This represents a preliminary step in the use of such a skin-equivalent in the treatment of human patients with wounds.

Filaggrin expression in normal and pathological skin. A marker of keratinocyte differentiation

Filaggrin is a basic, histidine-rich protein synthesized by cells of keratinizing epithelia, that subserves major physiological functions in maturating epidermis. Its precursor, profilaggrin, constitutes a major component of kertohyalin granules. In this work the expression of profilaggrin/filaggrin was studied in 140 specimens of normal human adult and fetal skin, cultured epithelia before and after allo- and xeno-grafting, and several cases of keratinization disorders and tumours. An avidin-biotin-alkaline phosphatase technique was applied on deparaffinized tissue sections, by using a specific monoclonal antibody (AKH1) to profilaggrin/filaggrin. The results show that the expression of profilaggrin/filaggrin is variously altered in keratinization disorders, whereas in epithelial proliferations it seems to decrease with an increasing degree of dedifferentiation of the tumour. Therefore the expression of these antigens can be considered to be a sensitive marker of maturation of normal epidermis and provides a new tool for the study of differentiation of the surface epithelium in skin diseases.

Sex, handedness and weight discrimination

Manual asymmetries in weight discrimination were investigated by testing 50 subjects with their left hand and 52 with their right hand, the groups being approximately balanced for sex and hand preference. Performance was better for the left-tested group, and for strongly handed males tested with the dominant hand. Female performance was unrelated to handedness. There was no overall superiority due to sex, males being superior with the dominant hand and females with the nondominant hand. The results are interpreted in terms of spatial hemisphere involvement, hand dominance, and the greater hemispheric specialization of males.

[Evaluation of the Engstrom metabolic computer]

The Engstrom Metabolic Computer (EMC), in association with the Erica Ventilator, uses indirect calorimetry to carry out continuous on-line gas exchange measurements. A laboratory assessment of the different parts of this equipment is described. The variability of FIO2 was less than 0.05. The accuracy and stability of the inspiratory flowmeter were only slightly modified by changes in the I/E ratio and gas flow rates. The overestimation of flow on increasing FIO2 was taken into account by the computer. The hygrometry of inspiratory and expiratory air samples reached that of room air, with an absence of saturation during prolonged measurements. The CO2 analyser also showed a good stability. The accuracy of the oxygen cell needed to be checked periodically. A global evaluation was carried out using Damask's method: a lung model was used into which CO2 and N2 were insufflated at precise rates to simulate CO2 production and O2 consumption. The measured respiratory quotient was also compared with the known RQ of burning methanol. The difference between measured and real values was less than 5%. Therefore, it was concluded that the EMC was reliable for indirect calorimetry measurements.

[Open approach to the subclavian vein for permanent cardiac stimulation]

In 97.5% of 562 successive attempts, puncture of the subclavian vein to introduce permanent pacemaker electrodes was made easier and safer by the incisional technique described in this report. The very low incidence (0.35%) of traumatic pneumothorax and the absence, after a long follow-up, of any infection or exteriorization of the pacemaker chamber were the main advantages of this technical variant.

Inhomogeneity in films: limitation of the accuracy of optical monitoring of thin films

With present-day refinements, thin film multilayers can be designed theoretically to meet virtually any reasonable filtering requirements. Often, when the optical properties are specified over very wide spectral regions the thicknesses of the various layers are not related in any simple way. The manufacture of such multilayers presents many difficulties. The tolerances on layer thickness and refractive indices in some designs are often very narrow. We have developed an optical method for the accurate control of layer thickness that involves the measurement of transmittance over a wide spectral region (400-1000 mm). This measurement is performed continuously during deposition by a rapid scanning monochromator. The accuracy of such a system depends on a precise knowledge of the indices of refraction that are produced during the multilayer deposition. In addition the structure of many optical thin films used for hard coatings departs considerably from the simple method that is traditionally used in optical coating designs. In the method we have developed to compensate for such discrepancies, optical inhomogeneity is included by assuming a linear refractive-index profile, determined by analyzing experimental results. These results are in agreement with other studies of structure.