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To clinically characterize and map the gene locus in a three-generation family with an X-linked adult-onset distal hereditary motor neuropathy.

The surface electronic structure of a PbS sample, cleaved in ultra-high-vacuum environment, has been studied with surface differential reflectivity (SDR) and angle-resolved photoelectron spectroscopy (ARUPS). The ARUPS spectra show the presence of two surface (resonance) states along the two angular directions [001] and [011]. SDR shows the existence of a gap of approximately 2.1 eV and two more optical transitions at energies of 2.7 and 3.1 eV. These transitions have been, tentatively, assigned to different points in the surface Brillouin zone.

The aim of the project was to develop micropropagation procedures for theheavily exploited and endangered South African trees black stinkwood (Ocotea bullata) and pepperbark (Warburgia salutaris) to facilitateconservation and reforestation. Both species are difficult to establish andgrow in tissue culture because of their high phenolic content. A protocol forthe establishment of explants in vitrowas developed comprisingdecontamination, the application of antioxidants and cold treatment.

The environmental effects of coal mining on the chemical composition of Trout Creek in Colorado are investigated using Individualized Differences Scaling and Canonical Correlation Analysis. Individualized Differences Scaling shows superiority over Canonical Correlation in the analysis of several matrices of measurements when the hypothesis of commonality of chemistry between each matrix cannot be justified a priori.

We studied the formation of InAs islands in holes defined by electron-beam lithography on GaAs substrates. The islands grew selectively in the holes, with one to nine islands per hole. The number of islands depends simply on the hole diameter, filling the holes at a constant effective two-dimensional density. We define the ratio of this effective density to the density on an unpatterned control sample to be the selectivity ratio, and we find a selectivity ratio of greater than 1000 for the present samples. We estimated the lateral conduction-band coupling for closely spaced islands and conclude them to be plausible candidates for weakly coupled device building blocks.

There is a growing awareness in the scientific community that as methods of analysis become more efficient, a massive data explosion is ensuing. Reducing data to meaningful trends has become a major aspect of research because of the bulk of information involved and because scientific interest is focusing on more and more subtle phenomena. One aid to data reduction and trend detection is pattern recognition, which is a collection of computer-based data manipulation techniques that have proved useful in a number of problems. This paper is intended as an illustrative introduction to these techniques, with the aim of giving the reader an intuitive feel for the process of a real application of the methods. A problem in archaeology, solved by neutron activation analysis, is discussed.

"Pattern recognition" is difficult to define because various terms have come to have different meanings to various groups. References to "pattern recognition," "learning machines," "machine decisions," "artificial intelligence," "empirical decision processes," and other names are scattered throughout the literature. Different groups of users, such as electrical engineers, physical scientists, neurobiologists, linguists, and psychologists, have adopted different phrases and have attached their own intrepretations to them. Even in chemistry conflicts in usage occur, as evidenced by the early use of "pattern recognition" in mass spectrometry to mean the direct comparison of one mass spectrum to a library of standards as an attempt to identify compounds. Indeed, one might say that all attempts to correlate information in any form amount to the recognition of patterns that represent that information. The problem becomes one of restricting the definition so that it can have some useful connotation.

Near-infrared Fourier transform (near-IR FT) Raman spectroscopy was used to predict mass percentages of liquid fuel mixtures without the use of an internal standard. The 29 mixtures making up the calibration set were composed of varying mass percentages of unleaded gasoline, superunleaded gasoline, and diesel. Predictions were made with the use of classical least-squares with the pure components. Root mean square error (RMSE) values for all samples were 13.5, 13.8, and 5.2% (absolute error) for unleaded, superunleaded, and diesel, respectively. Using an estimate of the pure spectra determined by calibration gave RMSE values of 13.3% for unleaded, 12.2% for superunleaded, and 5.0% for diesel. A partial least-squares (PLS) model was able to partially compensate for matrix effects. Using different portions of the Raman spectra reduced the RMSE to 5.7% for unleaded, 5.2% for superunleaded, and 1.3% for diesel.

Measurements of specific heat as a function of temperature were carried out with a differential scanning calorimeter on rape-seed, soybean, sunflower and corn oils and on lard.

The relationship enthalpy of mixing and excess molar volume of mixing versus composition were studied at 313.15 K for binary systems of 2,4,6-collidine with normal aliphatic alcohols. It was found that at this temperature the values ofHE andVE are negative and change with the length of the alkyl group of the alcohol.

We classified microorganisms from the clinical laboratory by using information provided by the Gram stain and antibiotic sensitivity profiles obtained with the Bauer-Kirby technique. Approximately 4,000 microorganisms, routinely identified and tested for antibiotic sensitivities in a large hospital microbiology laboratory, were used as a data set for several pattern recognition classification methods: K--nearest-neighbor analysis, statistical isolinear multicomponent analysis, Bayesian inference, and linear discriminant analysis. K--nearest-neighbor analysis yielded the highest prospective classification accuracy for gram-negative organisms, 90%. When those organisms displaying an atypical antibiotic resistance pattern were excluded from the data, the gram-negative classification accuracy improved to 95%. These results are inferior to currently accepted biochemical identification methods. Microorganisms with atypical antibiotic resistance patterns are likely to be misidentified and are common enough (17% of our isolates) to limit the feasibility of routine identification of microorganisms from their antibiotic sensitivities.

A general-purpose interface for the PDP-11 family of minicomputers is described. The interface, oriented toward laboratory data-acquisition and experimental control applications, can be built in a relatively short time with low materials costs. A general purpose, FORTRAN-compatible software package capable of driving the interface is also discussed.

The quinoxaline-di-N-oxides carbadox, olaquindox, and quindoxin, which are potent antibacterial agents, were tested for mutagenicity in the Salmonella microsomal system. They all induced base pair substitutions and frameshift mutations in Salmonella, and occurred independently of the presence of a rat liver microsomal fraction in the test system. Mutagenicity was dependent on the presence of their N-oxide groups, since quinoxaline, a completely reduced derivative of quindoxin, was not mutagenic, whereas the partially reduced quinoxaline-N-oxide exhibited a lower mutagenic activity than quindoxin. recA and uvrB Salmonella were found to be more susceptible to mutagenic quinoxaline derivatives than wild-type strains. The mutagenicity of quinoxaline-di-N-oxides was enhanced under anaerobic incubation as was the antibacterial activity. These results suggest that both the antibacterial and mutagenic activity of quinoxaline-di-N-oxides depend upon the same bacterial activation mechanism.

A new excitation source has been developed for x-ray emission analysis of high atomic number elements. A mixture of the sample and a small amount of boron-10 is irradiated in a thermal neutron beam and the resultant x radiation is recorded using a Ge(Li) semiconductor detector and a multichannel analyzer. The boron-10 undergoes neutron capture (10B(n,α)7Li, σ = 3840b) producing a single excited state of lithium-7 in 92.5% of the captures. Lithium-7mdecays with a half-life of about 5×10−14sec emitting a monoenergic 477 keV gamma ray. These gamma rays are in excellent geometry to the sample and are sufficiently energetic to excite the Kx radiation of the highest atomic number elements known. The Kx-ray spectra of several elements are presented along with a discussion of sample preparation and apparatus optimization.

Cold treatment of surface sterilized explant material of hardwood trees at 4°C for two or four days reduced or eradicated internal contamination with Bacillus subtilis. This procedure provides a cheap, rapid and non-toxic technique to introduce material from adult trees, growing out of doors, into culture.

An all-fibre optical time-division multiplexer based on a Sagnac loop has been developed and theoretically analysed. In addition to the low loss insertion, the simplicity of this setup and the low cost of these devices, the major advantage is that the output pulses have the same fixed power regardless of the input polarisation. The experimental results were found to be in agreement with the theoretical analysis. This device allows us to achieve mechanically stable multiplexing of a pulse generator signal from 10 to 20 GHz.