Nurse recognition of early deviation in development in home videos of infants with Rett disorder.

BACKGROUND: In the genetic Rett disorder (RD), infants make some progress then suffer a dramatic developmental regression, usually before 2 years of age. Home videos, taken before the problems are recognized, offer an objective source for detecting early signs. METHODS: Thirty-six health visitors and midwives were invited to view brief examples from home videos of a cohort of 14 infants with RD and 11 control infants with normal development in the first year of life, and to indicate, by pressing a button, points in the recordings which aroused their suspicion of developmental deviation. They were then invited to comment on their selection. The participants were blind as to whether any individual example showed an infant with normal development or one with some form of developmental disturbance. RESULTS: From the first month of life and throughout the first year, infants with RD received more button presses than controls (46%, 361 out of 778 viewings) in comparison with the control group (12%, 67 of 558). The consistent nature of the health professionals' comments made possible their categorization under four headings: appearance, posture, movement and contact. In the first month of life, the hand postures of infants with RD received particular comment from midwives (23 out of 37 comments overall on posture). CONCLUSIONS: The present study strongly suggests the presence of early signs of developmental deviation in infants with RD, although, in most cases, formal developmental screening procedures have failed to detect these before the ages of 12 or 18 months.

Computer anxiety: a comparison of pen-based personal digital assistants, conventional computer and paper assessment of mood and performance.

The recent growth of pen-based devices, such as the Personal Digital Assistant (PDA), offer mobility and a more natural interface than that of a conventional computer. The feasibility and application of the PDA for mood and cognitive assessment were investigated by examining possible interactions of individual characteristics and administration medium. Previous studies have provided evidence that individual characteristics of 'computer anxiety' and 'private self-consciousness' divergently covaried with mood scores measured by computer and paper methods. To investigate the relationship between individual characteristics and medium effects, 136 paid participants were allocated to and completed mood assessment tasks and a short battery of cognitive tasks by either the computer, PDA or the paper method. Self-ratings of mood measured by these three modalities covaried divergently with measures of computer anxiety and private self-consciousness. In addition, computer anxiety covaried with reaction time on the visual search task obtained on computers, but there was no such relationship when measured by a PDA. These results show that computer anxiety can affect the results of assessments of cognitive function as well as of mood ratings, and suggest that pen-based systems may have advantages over conventional computers in this respect.

Repeatability of the composition of titanium oxide films produced by evaporation of ti 2 o 3.

Congruent vaporization is a process that yields constant vapor species. Ti(2)O(3) was continuously electron-beam evaporated to produce titanium oxide thin films. Rutherford backscattering spectrometry was employed to study the evolution of the composition of these films. It seems that congruent vaporization can be established in a coating plant. TiO(2) films produced by conventional reactive deposition tend to contain mixtures of titanium oxides. Increasing the transmission of TiO(2) films becomes an issue of increasing the TiO(2) component in the films by adequate reactive evaporation.

Coupled plasmon-waveguide resonators: a new spectroscopic tool for probing proteolipid film structure and properties.

A variant of surface plasmon resonance (SPR) spectroscopy has been developed that involves a coupling of plasmon resonances in a thin metal film and waveguide modes in a dielectric overcoating. This new technique is referred to as coupled plasmon-waveguide resonance (CPWR) spectroscopy. It combines a greatly enhanced sensitivity (due to increased electromagnetic field intensities at the dielectric surface) and spectral resolution (due to decreased resonance linewidths), with the ability to directly measure anisotropies in refractive index and optical absorption coefficient in a dielectric film adsorbed onto the surface of the overcoating. Experimental data obtained with an egg phosphatidylcholine bilayer are presented to document these properties.

Using surface plasmon resonances to test the durability of silver-copper films.

Silver has high reflectivity in the visible and infrared but cannot be used fully because of its distressing lack of durability. A technique that uses the surface plasmon resonance phenomenon offers a sensitive method for studying the corrosion of silver and assessing improvements. It has been used in the investigation of the effects of flashing a thin layer, approximately 1 nm thick, of copper over silver in an attempt at cathodic protection. Tests include exposing silver and silver-copper films to air, 94% relative humidity, water, and hydrogen sulfide.

Optical-constant calculation over an extended spectral region: application to titanium dioxide film.

An iterative algorithm has been developed that takes starting values derived by an envelope method but then minimizes the influence of the envelopes and emphasizes the actual measured data. This combination avoids the difficulties inherent in the accurate drawing of the envelopes and makes it possible to extract the thickness and the optical constants of semiconducting and dielectric films over a wide spectral region, including regions of high absorption.

Conformational changes in rhodopsin probed by surface plasmon resonance spectroscopy.

Surface plasmon resonance (SPR) spectroscopy has been used to follow incorporation and light-induced conformational changes in bovine rhodopsin reconstituted into an egg phosphatidylcholine bilayer deposited on a thin silver film. The magnitude of the SPR spectral changes caused by light varies with pH in a manner paralleling that in flash photolysis experiments, which monitor formation of metarhodopsin II. Irradiation produces an increase of approximately 4 A in the average thickness of the proteolipid layer, consistent with exposure of recognition sites for the G protein. The results demonstrate that the SPR technology described herein may be used to monitor conformational events in membrane-associated receptors such as rhodopsin.

Assembly and molecular organization of self-assembled lipid bilayers on solid substrates monitored by surface plasmon resonance spectroscopy.

The structural properties of lipid films, made from a squalene/butanol solution containing varying amounts (0-15 mg/ml) of egg phosphatidylcholine and deposited on a thin metallic silver layer, were investigated using surface plasmon resonance (SPR) spectroscopy. Optical parameters (thickness, refractive index and extinction coefficient) of such supported self-assembled lipid membranes were obtained from a theoretical analysis of the experimental SPR curves. The mass of the lipid membrane and the area and volume occupied by one lipid molecule were also calculated. The results were consistent with the formation of durable and homogeneous lipid bilayers on the solid substrate, and indicated similarities in structural properties between the present lipid bilayers and freely suspended and Langmuir-Blodgett bilayer membranes. Such bilayers represent a simple model for biological membranes, as well as providing a means of immobilizing proteins for various practical applications, including receptor-based sensors and molecular devices. The results confirm the value of the SPR technique for investigating the properties of thin biomolecular dielectric films deposited on a metal surface.

Parents' evaluations of pre-school services for children with Down syndrome in two Scottish regions.

Parental evaluations of current pre-school provision for children with Down's syndrome were surveyed in two Scottish regions. Two methods were used: postal questionnaires and telephone interviews. Services covered were those provided by general practitioners, hospital specialists, health visitors, speech therapists, occupational therapists, physiotherapists, educational psychologists, home teachers, social workers and voluntary organizations. Regional differences were found in provision and in parental satisfaction with currently available services, with some of these differences being dependent on child age. Overall, parents felt they were being given insufficient professional support, with contradictory advice not uncommon. Findings indicate that if limited resources are to be used to the maximum benefit of family and child, both subjective and objective measures of the relative values of different kinds of support at different ages are urgently needed.

Feature issue on optical interference coatings.

The feature issue on Optical Interference Coatings, stimulated by the June 1992 Topical Meeting, covers the wider field of optical surface treatments after polishing. It is the latest in a series that has been running every four years since 1976.

Optimized design of an antireflection coating for textured silicon solar cells.

The short-circuit current density of a solar cell is used as a merit function to optimize solar cell antireflection coating designs. J(sc)/J(max) ratios reach 99%, even with a 10-nm-thick passivation layer.

Planarizing technique for ion-beam polishing of diamond films.

Diamond films, deposited on silicon substrates through microwave-assisted chemical vapor deposition, have been polished with a 500-eV beam of oxygen ions through the use of a planarizing layer. The films' surface roughness, in excess of 1 microm (rms) and 6 microm (peak to valley), was reduced to 35 nm (rms) and 217 nm (peak to valley). The polished films retained their diamond character and surface contamination was negligible. With this polishing process, optical applications of diamond films in the near infrared region are realizable.

New Christiansen filters.

A number of new optical filters that are based on the well-known Christiansen effect of scattering light in a heterogeneous medium have been fabricated. In addition to the conventional solid-in-liquid systems, we fabricated some solid-in-solid filters, which we refer to as solid Christiansen filters. Here we report on their fabrication, performance, and applications. From our experiments we have also derived the dispersion curve for a liquid styrene monomer in the visible region.

Oxygen-ion beam polishing of a 5-cm-diameter diamond film.

A 5-cm diameter, 1-microm (peak to valley) rough diamond film has been polished to optical quality by an oxygen-ion beam. The rms and peak-to-valley roughness values of the polished surface have been lowered to 5.5 and 55.4 nm, respectively. Reactive ion beam polishing provides a low-temperature (140 degrees C), noncontact, and precisely controllable approach to improving the surface quality of diamond films. This progress is essential to the use of diamond coatings in optical applications.

Effects of nalmefene on feeding in humans. Dissociation of hunger and palatability.

Effects of nalmefene on eating were investigated in two groups of ten male volunteers, in a double-blind placebo-controlled study. The nalmefene treated group ate 22% less, both in terms of absolute weight and caloric intake, of a standardised buffet-meal than did the placebo group. No differences in subjective ratings of hunger or satiety were found between the groups, suggesting that the reduced feeding was not a consequence of any change in motivation to eat. When analysed by nutrient content, nalmefene was found to reduce fat and protein, but not carbohydrate, intakes. Analyses of intakes of individual foods showed a differential effect of nalmefene on foods rated as highly palatable. Thus the apparent nutrient specificity of nalmefene appeared to be an indirect consequence of its effect on palatability. Nalmefene also caused slight increases in self-rated alertness, and decreases in ratings of tiredness and elation, although it was thought unlikely that these accounted for observed changes in eating behaviour. No other side-effects were detected, and performance on a choice reaction time task was unaffected. These results add weight to suggestions that endogenous opioids are involved in reward-related aspects of feeding associated with food palatability.

Optical interference coatings: introduction by the feature editors.

This introduction briefly reviews the history of the series of topical meetings on optical interference coatings and defines the scope of the features in this 15 July 1989 issue on the papers from the Fourth Topical Meeting.