Stereotactic core biopsy of breast microcalcifications. Aid to diagnosis?]

We assessed the accuracy with which stereotactic core biopsy of breast microcalcifications helps to justify follow-up or indicate required surgical planning. Eighty-nine patients underwent stereotactic breast biopsy performed with large core needles. Histopathologic findings of microbiopsies were correlated with radiological findings, with follow up and with surgical findings. Agreement between radiological and histopathologic findings on biopsies was obtained in 86% for benign results. Even in the case of benign radiological findings, the histological results of microbiopsies required a surgical biopsy justified in 10% of cases. Radiologically suspicious or malignant microcalcifications were correlated with 35% benign and 65% malignant histologies on biopsies. The positive predictive value, negative predictive value and accuracy were respectively 93%, 86% and 95%. Invasive lesions were found on microbiopsies in 39% of excised malignant lesions. Multifocal lesions were proved on microbiopsies in 50% of all excised carcinomas. Microbiopsies help to disclose malignant lesions undetected on radiological analysis, and may obviate diagnostic surgical biopsy in many cases.     

Graphitization studies of cured phenolic resins by high-resolution 13C-cross-polarization magic angle spinning solid-state NMR spectroscopy

¹³C-cross-polarization/magic angle spinning solid-state NMR spectroscopy is used to investigate the graphitization process of a pyrolyzed formophenolic resin. The formation of a 2-dimensional graphitelike lattice, growing with the duration of the laser pyrolysis, is shown. A one-parameter-condensation model is used to estimate, from our dipolar-dephasing NMR experimental data, the quaternary-to-tertiary aromatic fraction, the number of condensed aromatic rings (from 10 to 23 units), and the average cluster diameter (from 9 to 14 Å).     

An Industrial Software Engineering Retraining Course: Development Considerations and Lessons Learned

Israel Aircraft Industries has recently been conducting a novel six-month intensive course to retrain practicing engineers to become software engineers working on embedded computer systems. The first course was concluded in January 1982 and the second course began in November 1982. This paper describes the objectives, educational philosophy, course content, and practical experience of the first course. It also describes how the second course was modified as a result of the lessons learned from the successes and failures of the first course.     

Phase transformations in Au(Fe) nano- and microparticles obtained by solid state dewetting of thin Au–Fe bilayer films

Sub-micrometer-sized particles of Au–Fe alloys were obtained by solid-state dewetting of single-crystalline Au–Fe bilayer films, deposited on c-plane sapphire (α-Al₂O₃) substrates. Depending on the annealing parameters, precipitation of an Fe-rich phase occurred on the side facets of the particles in an interface-limited reaction. Based on the literature values of surface and interface energies in the system, the precipitates were expected to grow inside the Au(Fe) particles, resulting in an (Fe) core–(Au) shell morphology. However, more complex, time-dependent precipitate morphologies were observed, with faceted Fe-rich precipitates attached to the parent faceted Au-rich particles of the same height being dominant at the last stages of the transformation. Our high-resolution transmission electron microscopy observations revealed a nanometric segregation layer of Au on the surface of Fe-rich particles and at their interface with sapphire. This segregation layer modified the surface and interface energies of the Fe-rich particles. A thermodynamic transformation model based on the concept of weighted mean curvature was developed, describing the kinetics of precipitations and morphology evolution of the particles during the dewetting process. Employing the values of surface and interface energies modified by segregation resulted in a good qualitative agreement between theory and experiment.     

Programming of crystal diameter in Czochralski growth by a cooling plot: Application to InSb

It is shown, that under thermal “stiffness” conditions, the dimensions of a crystal grown by the Czochralski method may be programmed by a cooling plot. The cooling plot is calculated from the measured longitudinal and radial thermal gradients, involving also the melt-to-solid densities ratio. Utilization of the principle could save the need for sophisticated expensive automatic diameter control systems. In the present work the principle was successfully applied to the growing of InSb single crystals of diameters around 2cm.     

Infrared dichroism and birefringence studies of silica-filled styrene–butadiene rubbers

Infrared and birefringence measurements are used to characterize the orientational behavior of silica-filled styrene–butadiene copolymers. The orientational data are correlated with the results of equilibrium swelling measurements. On the other hand, the role played by a silane couling agent bis(3-triethoxysilylpropyl)tetrasulfide (TESPT), or “Si69”) on rubber/silica system is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1006–1012;2001     

Eukaryotic Antimicrobial Peptides: Promises and Premises in Food Safety

ABSTRACT:  There is a lack of efficient and safe preservatives in the food industry. Massive use of some common food preservation methods has led, over the years, to development of a resistance to different treatments by various food pathogens. Enteric bacteria are especially tolerant to adverse environmental conditions—such as low pH and high salt concentrations— which limits efficiency of some preservation methods. Consumers demand for natural, preservative-free, and minimally processed foods and worldwide concern regarding disease outbreaks caused by food-related pathogens have created a need for development of new classes of antimicrobial (AM) agents. The twentieth century revealed a massive array of new peptide-based antimicrobials. Small ribosomally made compounds are found in practically all living species where they act as important component of host defense. Certain indubitable advantages of peptides—pertaining to simplicity, activity spectra, and bacterial resistance—over known preservative agents advocate their potential for food preservation. Nisin, an AM compound originating from bacteria, is so far the only FDA-approved peptide. However, a growing number of reports describe the potential of animal-derived antimicrobial peptides as food preservatives. These studies have yielded various native compounds and/or derivatives that possess markedly improved antimicrobial properties under a broad range of incubation conditions. The present work reviews the most investigated peptides and accounts for their potential use as alternatives to the preservatives used today. The focus is on research aspects aiming at understanding the mechanism of action of these peptides at extreme environments of various food systems. Collectively, the data accumulated are convincingly indicative of potential applications of these peptides in food safety, namely, with respect to fighting multidrug-resistant pathogens.     

On the role of Fe in the growth of single crystalline heteroepitaxial Au thin films on sapphire

Thin Au–Fe bilayers were deposited on c-plane sapphire (α-Al₂O₃) substrates at room temperature employing the electron beam deposition method. The layers were found to be single crystalline (i.e. the grain size was much larger than the film thickness), with a [1 1 1] and [1 1 0] texture for Au and Fe, respectively, and strong heteroepitaxy to the substrate. Au films deposited on sapphire and Au–Fe bilayers deposited on amorphous SiO₂ were polycrystalline and exhibited random in-plane orientation of the grains. The effects of Fe and the Fe–sapphire interface on the microstructure of the Au film were investigated and discussed in terms of the orientation relationships, in-plane strain, interface energy and adhesion. The microstructures of annealed and as-deposited films were very similar, indicating that as-deposited films are close to thermodynamic equilibrium in terms of the orientation relationship with the substrate. This is uncommon for non-equilibrium thin film deposition processes, which usually result in a high density of defects in the as-deposited films.