Library

Notes: Hafnium and zirconium silicate (HfSixOy and ZrSixOy, respectively) gate dielectric films with metal contents ranging from ∼3 to 30 at. % Hf, or 2 to 27 at. % Zr (±1 at. % for Hf and Zr, respectively, within a given film), have been investigated, and films with ∼2–8 at. % Hf or Zr exhibit excellent electrical properties and high thermal stability in direct contact with Si. Capacitance–voltage measurements show an equivalent oxide thickness tox of about 18 Å (21 Å) for a 50 Å HfSixOy (50 Å ZrSixOy) film deposited directly on a Si substrate. Current–voltage measurements show for the same films a leakage current of less than 2×10−6 A/cm2 at 1.0 V bias. Hysteresis in these films is measured to be less than 10 mV, the breakdown field is measured to be EBD∼10 MV/cm, and the midgap interface state density is estimated to be Dit∼1–5×1011 cm−2 eV−1. Au electrodes produce excellent electrical properties, while Al electrodes produce very good electrical results, but also react with the silicates, creating a lower ε layer at the metal interface. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy indicate that the dielectric films are amorphous silicates, rather than crystalline or phase-separated silicide and oxide structures. TEM shows that these films remain amorphous and stable up to at least 1050 °C in direct contact with Si substrates. © 2000 American Institute of Physics.

Notes: An optical sensor containing polarizing optical components has been constructed to monitor fluorescence anisotropy during polymer processing and to carry out remote sensing of polymer products doped with fluorescent dyes. The sensor is a compact unit that is used to polarize incident excitation light as well as to analyze the polarization of generated fluorescent light. Optical fibers are used to carry light between the sensor head and the light source and detecting equipment. The anisotropy measurement yields information about the orientation of a fluorescent dye molecule that has been doped into polymer matrix. Fluorescent dyes that have geometrical asymmetry in their molecular structure are used. Experiments are described for which the sensor is positioned in line during extrusion, during specimen extension, and where the sensor is used to carry out area scans of films and sheets. Measurements were made on polyethylene, polyethylene terephthalate, and polybutadiene resins that contained a low concentration of fluorescent dye.

Notes: Intertidal restoration through realignment of flood defenses has become an important component of the U.K. coastal and estuarine management strategy. Although experimentation with recent deliberate breaches is in progress, the long-term prognosis for salt marsh restoration can be investigated at a number of sites around Essex, southeast England where salt marshes have been reactivated (unmanaged restoration) by storm events over past centuries. These historically reactivated marshes possess higher creek densities than their natural marsh counterparts. Both geomorphology and sedimentology determine the hydrology of natural and restored salt marshes. Elevation relative to the tidal frame is known to be the primary determinant of vegetation colonization and succession. Yet vegetation surveys and geotechnical analysis at a natural marsh, where areas with good drainage exist in close proximity to areas of locally hindered drainage at the same elevation, revealed a significant inverse relationship between water saturation in the root zone and the abundance of Atriplex portulacoides, normally the physiognomic dominant on upper salt marsh in the region. Elsewhere in Essex natural and restored marshes are typified by very high sediment water contents, and this is reflected in low abundance of A. portulacoides. After a century of reestablishment no significant difference could be discerned between the vegetation composition of the storm-reactivated marshes and their natural marsh counterparts. We conclude that vegetation composition may be restored within a century of dike breaching, but this vegetation does not provide a reliable indicator of ecological functions related to creek structure.

Notes: In this study we examine whether stabilization of denuded coastal foredunes in southeastern Australia with the exotic grass species Ammophila arenaria (marram grass) restores plant and ground-active arthropod assemblages characteristic of undisturbed foredunes. Vascular plants and arthropods were sampled from foredunes that had been stabilized with marram grass in 1982, and from foredunes with no obvious anthropogenic disturbance (control dunes). All arthropods collected were sorted to Order, and ants (81.5% of all specimens) were further sorted to morphospecies. Abundance within arthropod Orders, as well as richness, composition, and structure of the plant and ant assemblages from control and stabilized dunes, were compared. The abundance of Diptera was significantly greater on stabilized dunes, while the abundance of Isopoda was significantly greater on control dunes. There were no significant differences in morphospecies richness or composition of ant assemblages on the two dunes types, although some differences in the abundances of individual morphospecies were observed. By contrast, stabilized dunes exhibited lower plant species richness and highly significant differences in plant species composition, due mainly to the large projected foliage cover of marram grass. The study revealed that after 12 years, the vegetation composition and structure of stabilized dunes was still dominated by marram grass and, as a result, invertebrate assemblages had not been restored to those characteristic of undisturbed foredunes.

Notes: Abstract: Inflammatory breast cancer is a rare but highly malignant form of breast cancer. Biopsy and histologic examination usually confirm the diagnosis. There are rare reports of difficulties in differentiating this particular type of breast malignancy from congestive heart failure (CHF). This difficulty arises when CHF is associated with unilateral breast edema and skin thickening. However, inflammatory breast carcinoma has distinctive histologic and microscopic characteristics allowing the establishment of a proper diagnosis. We report the case of a 65-year-old woman with CHF associated with unilateral breast edema and skin thickening simulating inflammatory breast carcinoma on mammography.

Notes: The steady-state level of amyloid β-peptide (Aβ) represents a balance between its biosynthesis from the amyloid precursor protein (APP) through the action of the β- and γ-secretases and its catabolism by a variety of proteolytic enzymes. Recent attention has focused on members of the neprilysin (NEP) family of zinc metalloproteinases in amyloid metabolism. NEP itself degrades both Aβ1−40 and Aβ1−42in vitro and in vivo, and this metabolism is prevented by NEP inhibitors. Other NEP family members, for example endothelin-converting enzyme, may contribute to amyloid catabolism and may also play a role in neuroprotection. Another metalloproteinase, insulysin (insulin-degrading enzyme) has also been advocated as an amyloid-degrading enzyme and may contribute more generally to metabolism of amyloid-forming peptides. Other candidate enzymes proposed include angiotensin-converting enzyme, some matrix metalloproteinases, plasmin and, indirectly, thimet oligopeptidase (endopeptidase-24.15). This review critically evaluates the evidence relating to proteinases implicated in amyloid catabolism. Therapeutic strategies aimed at promoting Aβ degradation may provide a novel approach to the therapy of Alzheimer's disease.

Notes: Objective  This study explores the predictive value for live birth following tubal reconstructive surgery of the ‘Hull and Rutherford’ (H&R) classification system.Design  Retrospective cohort study.Setting  Tertiary infertility referral service, University of Bristol.Population  Infertile women younger than 40 years with tubal damage undergoing tubal surgery.Methods  Women (n= 192) were grouped according to three severity grades of disease based on the H&R classification. Essentially, the main features of grade I tubal damage were filmy adhesions, whereas grades II and III referred to unilateral severe damage and bilateral severe damage, respectively. Standard surgical techniques were employed. Pregnancy and live birth rates were calculated and compared using time-specific univariate Kaplan–Maier curves and multivariate Cox's regression analysis.Main outcome measures  Pregnancy, ectopic and live birth within three years of surgery.Results  A significant trend towards higher ectopic pregnancy rates (P 〈 0.001) with increasing severity of tubal damage was noted, but not miscarriage rates. Univariate analysis revealed significant differences in the live birth rates of 69%, 48% and 9% for grades I, II and III, respectively. Multivariate analysis (controlling for age, duration of and primary infertility) confirmed these differences to be significant with risk ratios of 13.7 (95% CI: 4.49–41.9) and 6.54 (95% CI: 2.48–17.24) for grades I and II disease, respectively, compared with grade III disease, used as the reference.Conclusions  The H&R classification is a simple classification system that is able to distinguish women into three distinct groups giving a favourable, fair and poor prognosis for live birth following tubal surgery.

Notes: Objectives 1. To determine the prevalence of endometrial hyperplasia in postmenopausal women taking standard proprietary regimens of sequential oestrogen/progestogen; 2. to determine the effects of nine months treatment with an oral continuous combined regimen of 2 mg 17ß-oestradiol and 1 mg norethisterone acetate (Kliofem [Kliogest outside the UK]; Novo Nordisk, Denmark) on endometrial histology in postmenopausal women.Design An open, prospective study in postmenopausal women.Setting Fifty-four menopause clinics in the UK.Participants 2028 postmenopausal women: 1312 (Group A) taking sequential oestrogen-progestogen hormone replacement therapy (HRT), and 716 (Group B) not taking HRT, were recruited. In Group A, 388 women took preparations containing 10 days of progestogen, 921 had 12 days, and 3 had 13 days per cycle.Methods Endometrial aspiration biopsies were taken towards the end of a three-month run-in period (Group A) or at study entry (Group B), before administration of the continuous combined HRT regimen. Biopsies were repeated at the end of the nine month treatment period.Main outcome measure Endometrial histology.Results Initial endometrial biopsy data were available for 1106 women in Group A, who by the time of endometrial investigation had been taking HRT for a median duration of 2.56 years (5th to 95th centiles: 0.77 to 8.49 years). Data were available for 661 untreated women, who had no bleeding and had not taken HRT within the last year (Group B). Complex hyperplasia was found in 59 women (5.3%), and atypical hyperplasia in a further eight (0.7%) in Group A. In Group B there were no cases with complex hyperplasia, but one woman showed atypical hyperplasia (0.2%). At the end of the nine months of continuous combined therapy there was no case of hyperplasia among 1196 biopsies (upper 95% confidence limit of risk 0.31%) in women completing the study. Within this Group all of the women with complex hyperplasia arising during previous sequential HRT and who completed the study (n= 38) reverted to normal endometrial patterns. There was no case of endometrial carcinoma during the study.Conclusions Despite taking standard regimens of sequential HRT containing at least 10 days of progestogen, there was a 5.3% prevalence of complex endometrial hyperplasia, and a 0.7% prevalence of atypical hyperplasia. However, continuous combined HRT (Kliofem) containing daily progestogen is not associated with an increased risk of hyperplasia and will convert the endometrium to normal in those with complex hyperplasia arising during previous sequential HRT.

Notes: This investigation examines the ability of the theory of reasoned action (TRA) to explain and predict adolescents' verbal (i.e., insulting) and physical (i.e., fighting) aggression, as well as behaviors that encourage aggression such as watching a fight or telling others about a fight that is going to happen. Subjects were 488 seventh-grade boys and girls enrolled in 2 public junior high schools in a large Midwestern U.S. city. Subjects completed a survey assessing components of the TRA as they related to the 4 behaviors under investigation. Consistent with the TRA, analysis revealed that attitudes and subjective norms predicted behavioral intent, and intent predicted behavior, for watching a fight, spreading rumors about a fight, and insulting. For fighting, however, attitudes, but not subjective norms, predicted behavioral intent, and intent predicted behavior. Implications for the TRA as well as for the development of youth violence prevention and intervention programs are discussed.