Higher ER Research Articles

RBS Lattice Site Location and Damage Recovery Studies in GaN

Erbium was implanted with 160 keV at doses between 5×1014 and 5×1015 at/cm2 into (0001) epitaxial GaN on sapphire and annealed at various temperatures between 600° and 1000° C. The RBS/Channeling technique was used to analyze the damage recovery during different annealing steps and to determine the lattice location of the implanted Er. For a sample implanted with 5×1014 and annealed for 30 min at 600° C a complete overlap of the Er and Ga angular scans across the <0001> axis was observed, indicating that 100% of Er occupies substitutional sites. Measurements along the <10 1> channel show that Er is located on Ga sites. The damage recovery was slightly better for the samples co-implanted with the same dose of Oxygen in an overlapping profile (E=25 keV). However, a complete recovery of the damage caused by the implantation was not achieved. Samples implanted with higher Er and O doses (5×1015 at/cm2 ) and at the same energies as above were annealed at 600° for 30 min and at 900°, 1000° C for 120 s using a proximity cap. The higher dose caused an almost complete amorphisation of the surface layer. After annealing indications of epitaxial regrowth were observed, however, the substitutional fraction remains substantially lower and the damage recovery is less complete.

Competing causes of death for primary breast cancer.

A patient's likelihood of dying from breast cancer or another cause can be assessed with competing risks analyses. Data for a cohort of 678 patients with primary invasive breast cancer accrued from 1971 to 1990, updated to 1995, included cause of death (e.g., breast cancer vs. other cause). We investigated the effects of age, tumor size, nodal status, ER, PgR, and adjuvant therapy (hormones, chemotherapy, radiotherapy) on type of death and time to death for patients of all ages and for those over the age of 65 years. Although there were no significant univariate differences in breast cancer death rates by age group (P=0.94), more patients over the age of 65 years died from other causes (41/207 [20%] of those older than 65 years vs. 16/471 [3%] of those younger than 65 years; P <.001). In competing risks analyses, older age was associated with non-breast cancer death, whereas larger tumor size was associated with breast cancer death. PgR was positively, and nodal status negatively, associated with survival, regardless of type. In the older patient group, the competing risks analyses identified similar effects for age and tumor size; in addition, higher ER assay values were less likely to be associated with breast cancer death. With increased lifespan, there will be more breast cancer cases in women older than 65 years; we have shown that women in this group have more non-breast cancer deaths. It becomes important, then, to delineate differential effects of prognostic factors on competing causes of death.

RBS Lattice Site Location and Damage Recovery Studies In GaN

AbstractErbium was implanted with 160 keV at doses between 5x1014 and 5x1015 at/cm2 into (0001) epitaxial GaN on sapphire and annealed at various temperatures between 6000° and 10000° C. The RBS/Channeling technique was used to analyze the damage recovery during different annealing steps and to determine the lattice location of the implanted Er. For a sample implanted with 5x1014 and annealed for 30 min at 600° C a complete overlap of the Er and Ga angular scans across the &lt;0001&gt; axis was observed, indicating that 100% of Er occupies substitutional sites. Measurements along the &lt;101&gt; channel show that Er is located on Ga sites. The damage recovery was slightly better for the samples co-implanted with the same dose of Oxygen in an overlapping profile (E=25 keV). However, a complete recovery of the damage caused by the implantation was not achieved. Samples implanted with higher Er and 0 doses (5x 1015 at/cm2) and at the same energies as above were annealed at 600° for 30 min and at 900°, 1000° C for 120 s using a proximity cap. The higher dose caused an almost complete amorphisation of the surface layer. After annealing indications of epitaxial regrowth were observed, however, the substitutional fraction remains substantially lower and the damage recovery is less complete.

Intra- and Inter-Laboratory Reproducibility of Estrogen and Progesterone Receptor Enzyme Immunoassay in Breast Cancer Cytosol Samples: A Swedish Multicenter Study

Estrogen and progesterone receptor analysis results were compared within and between six laboratories in Sweden using frozen breast cancer cytosol samples, and the same technique (enzyme immunoassay, Abbott Laboratories). The concordance in receptor status (positive vs. negative) was excellent (98.4% (571/580)). The discordant results were attributable to values near cut-off (n = 4) or outliers (n = 5), the latter probably being due to analytical errors. One laboratory reported significantly higher ER concentrations than the others: thus caution should be observed when comparing absolute values from different centers. For PgR there were similar differences between the laboratories. However, the intra- and inter-laboratory differences were small compared with the overall variability in ER and PgR content between different samples in a large database. The range of the median intra-laboratory coefficient of variation was 11–23% for ER and 12–19% for PgR. indicating that there is room for improvement in the quality of assay performance.

Concentration and annealing effects on photoluminescence and local structure of Er-implanted silica

Abstract Extended X-ray absorption fine structure (EXAFS) and photoluminescence (PL) measurements were performed on Er-implanted silica as a function of concentration and annealing at 900°C for 30 min. Er was implanted at 5 MeV to form peaked concentration profiles, as well as at a range of energies to form nearly-flat profiles over 1.5 μm of depth. Peak concentrations ranged from 0.1 to 1.0 at.%. It is found that, for low (0.1 at.%) concentrations, local structure is unaffected by annealing, while the lifetime increases. It is suggested that the lifetime is determined by defects in the glass matrix. For higher concentrations, the ErO distance increases from 2.1 A to 2.24 A, the latter value being close to that found in bulk glasses. As a function of Er concentration and annealing, certain PL features evolve in a manner correlated with the EXAFS distances and coordination numbers. The effect of annealing becomes more pronounced at higher Er concentrations. It is suggested that some of the same structural features affect both probes.

Effect of bso on the radiation response at low (0–4 Gy) doses

Depletion of thiols by various agents has been shown to radiosensitize hypoxic cells. The agent BSO is used to specifically inhibit GSH synthesis, and the effect of this treatment on radiation response, particularly in the region of clinical interest, was studied using automated microscopic identification of cells for measurement of high survival levels. In both CHO and V79 cell lines, the enhancement rations were greater at low doses (80% S) than at high doses (2% S) in cells irradiated in hypoxia. GSH depletion also affected the aerobic response in both dose regions, with again higher ER's observed at low doses. These results support previous studies which suggest that GSH levels affect the shoulder portion of the survival curve. However, as with untreated cells, the OER's remain higher at high doses than at low doses, in BSO treated cells of both lines. These studies complement an earlier low-dose study on diamide by Skarsgard and co-workers, and were carried out to increase our understanding of the factors which affect radiation sensitivity in the range of doses used in fractionated regimens in the clinic.

Enzyme immunoassay of oestrogen receptors in needle biopsies from human liver

For quantitative assessments of sex hormone receptors in liver tissue, ligand binding assays are inconvenient, as they require large biopsies (0.5-1.0 g). The present study shows that it is possible to measure oestrogen receptors (ER) quantitatively in needle biopsy specimens as small as 10 mg by modifications of a commercial enzyme immunoassay employing monoclonal antibodies. Sucrose gradient centrifugation and the dextran charcoal method served as reference methods. A consecutive series of needle biopsies from patients suspected of liver disease were investigated. The biopsies (n = 37) had a median weight of 14 mg and cytosolic protein concentrations greater than 1 mg/ml (median 1.28 mg/ml). The median ER concentration was 20 fmol/mg cytosolic protein (range 5 to 57 fmol/mg). The intra-assay coefficient of variation was 8.9%, the inter-assay 13.2%, and the detection limit 2.7 fmol/ml cytosol. Women had significantly higher ER concentrations (median 22 fmol/mg) compared to male patients (median 16 fmol/mg) (P = 0.007). The enzyme immunoassay measures ER in liver specimens as small as 10 mg, compared to the large tissue specimens necessary for the conventional DCC assay, and the method is a convenient tool for further studies of ER in routine needle biopsies from the liver.

Heterogeneity of oestrogen receptors in human breast tumours

ABSTRACT In a series of 50 breast tumours, oestrogen receptor (ER) measurements obtained by a single saturating dose (SSD) dextran coated charcoal assay were compared to those obtained by Scatchard analysis. In 45 ER+ve tumours there was good correlation between the two methods thus validating the SSD for ER measurement. However, Scatchard analysis revealed considerable heterogeneity in the affinities of the ER. This variation was most pronounced in tumours containing less than 60 fmol. ER/mg protein (Kd's ranged from 0.05 to >2nM). Analysis of tumours with higher ER contents showed a more homogeneous population with lower dissociation constants. Biphasic Scatchard plots were obtained in 10 out of the 50 tumours indicating the presence of at least two high affinity oestrogen binding moieties. It is suggested that variability in responses to endocrine therapy may be related to the heterogeneity of ER present in breast tumours.

The effect of age on estrogen and progesterone receptor in primary breast cancer.

We evaluated the estrogen receptors (Er) and progesterone receptors (Pr) in 228 female patients with primary breast cancer by Dextran-Charcol method. Their ages vary from 30 to 91 years. Mean age 60.7 years. (SD: 13.6 years). Er mean was 70.31. (SD:103); there exists a statistically significant correlation between age and Er at p less than .001; older patients have higher Er. Pr mean was 60.73, (SD:128). There is statistically significant correlation between age and Pr at .01 less than p less than .025; older patients have higher Pr. There is also very statistical significant correlation between Er and Pr at p less than 0.1; when Er is high Pr is high.

Transepidermal water loss in full-term and pre-term infants.

The amount of water lost from the skin and the relation of the water loss to environmental factors, activity, body temperature, gestational age, nutritional status at birth and post-natal age were studied in full-term and pre-term newborn infants. The method we used was non-invasive and based on determination of the water vapour pressure gradient immediately above the skin surface. We found that the transepidermal water loss per unit time and area (TEWL; g/m2 h) could be calculated by using values from only three measurement sites. TEWL increased with activity and when body temperature was elevated above 37.1 degrees C. On the first day after birth TEWL in appropriate for gestational age (AGA) infants was exponentially related to gestational age, with much higher values in the most pre-term infants than in full-term infants. In full-term small for gestational age (SGA) infants TEWL was significantly lower than in full-term AGA infants. In pre-term and full-term AGA infants and in full-term SGA infants we found an inverse linear relationship between ambient humidity and evaporation rate (ER; g/m2 h) from the skin. The level of ER and the slope of the relationship depended on the gestational age of the infant, with higher ER in the more pre-term infants. Analysis of the relationship between ambient humidity and ER indicated that there is a gradual change in the permeability of the skin with gestational age. In pre-term infants TEWL gradually decreased during the first weeks of life. In full-term AGA infants TEWL was almost unchanged during these first weeks.

CAPITAL ASSET PRICES: A THEORY OF MARKET EQUILIBRIUM UNDER CONDITIONS OF RISK*

One of the problems which has plagued thouse attempting to predict the behavior of capital marcets is the absence of a body of positive of microeconomic theory dealing with conditions of risk/ Althuogh many usefull insights can be obtaine from the traditional model of investment under conditions of certainty, the pervasive influense of risk in finansial transactions has forced those working in this area to adobt models of price behavior which are little more than assertions. A typical classroom explanation of the determinationof capital asset prices, for example, usually begins with a carefull and relatively rigorous description of the process through which individuals preferences and phisical relationship to determine an equilibrium pure interest rate. This is generally followed by the assertion that somehow a market risk-premium is also determined, with the prices of asset adjusting accordingly to account for differences of their risk.