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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 63 (1991), S. 2069-2073 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The use of moderate energy electron beams (e-beams) to generate plasma can provide greater control and larger area than existing techniques for processing applications. Kilovolt energy electrons have the ability to efficiently ionize low pressure neutral gas nearly independent of composition. This results in a low-temperature, high-density plasma of nearly controllable composition generated in the beam channel. By confining the electron beam magnetically the plasma generation region can be designated independent of surrounding structures. Particle fluxes to surfaces can then be controlled by the beam and gas parameters, system geometry, and the externally applied rf bias. The Large Area Plasma Processing System (LAPPS) utilizes a 1–5 kV, 2–10 mA/cm2 sheet beam of electrons to generate a 1011–1012 cm−3 density, 1 eV electron temperature plasma. Plasma sheets of up to 60×60 cm2 area have been generated in a variety of molecular and atomic gases using both pulsed and cw e-beam sources. The theoretical basis for the plasma production and decay is presented along with experiments measuring the plasma density, temperature, and potential. Particle fluxes to nearby surfaces are measured along with the effects of radio frequency biasing. The LAPPS source is found to generate large-area plasmas suitable for materials processing. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An analysis is presented for the production of weakly ionized plasmas by electron beams, with an emphasis on the production of broad, planar plasmas capable of reflecting X-band microwaves. Considered first in the analysis is the ability of weakly ionized plasmas to absorb, emit and reflect electromagnetic radiation. Following that is a determination of the electron beam parameters needed to produce plasmas, based on considerations of beam ionization, range, and stability. The results of the analysis are then compared with a series of experiments performed using a sheet electron beam to produce plasmas up to 0.6 m square by 2 cm thick. The electron beam in the experiments was generated using a long hollow-cathode discharge operating in an enhanced-glow mode. That mode has only recently been recognized, and a brief analysis of it is given for completeness. The conclusion of the study is that electron beams can produce large-area, planar plasmas with high efficiency, minimal gas heating, low electron temperature, high uniformity, and high microwave reflectivity, as compared with plasmas produced by other sources. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 62 (1991), S. 2895-2903 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A multi-element segmented concentric Faraday collector has been developed for measuring the time evolution of the beam half-current radius (a1/2) of an intense relativistic electron beam. Each collector segment measures the total current within its radius. The data analysis procedure fits the data from all five segments at a given time to a prescribed beam profile and calculates a1/2 from the parameters of the fitted curves. The effect of beam centroid offsets on the data analysis was investigated numerically. Beam centroid offsets as large as half the beam radius produce only a 10% error in the experimental measurement of a1/2. The use of a thin graphite overlayer followed by range-thick stainless steel reduces scattering from one collector element to the next. The instrument has been used extensively on the SuperIBEX relativistic electron beam accelerator for measurement of the half-current radius as a function of time. Radius variations in excess of 4:1 have been measured over the duration of the beam pulse for beams with 5-MeV energy, 20-kA peak current and 1-cm final half-current radii.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 850-862 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ta2O5 is a candidate for use in metal–oxide–metal (MOM) capacitors in several areas of silicon device technology. Understanding and controlling leakage current is critical for successful implementation of this material. We have studied thermal and photoconductive charge transport processes in Ta2O5 MOM capacitors fabricated by anodization, reactive sputtering, and chemical vapor deposition. We find that the results from each of these three methods are similar if one compares films that have the same thickness and electrodes. Two types of leakage current are identified: (a) a transient current that charges the bulk states of the films and (b) a steady state activated process involving electron transport via a defect band. The transient process involves either tunneling conductivity into states near the Fermi energy or ion motion. The steady state process, seen most commonly in films 〈300 Å thick, is dominated by a large number of defects, ∼1019–1020 cm−3, located near the metal–oxide interfaces. The interior of thick Ta2O5 films has a substantially reduced number of defects. Modest heating (300–400 °C) of Ta2O5 in contact with a reactive metal electrode such as Al, Ti, or Ta results in interfacial reactions and the diffusion of defects across the thickness of the film. These experiments show that successful integration of Ta2O5 into semiconductor processing requires a better understanding of the impact of defects on the electrical characteristics and a better control of the metal–Ta2O5 interface. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 762-763 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact, four-way, optical image splitter is described which maintains equal intensity and equal optical path length in each arm of the apparatus. The four output beams are parallel with the input light beam.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    238 Main Street, Cambridge, MA 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 4 (1994), S. 0 
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This work compares glutathione levels, glutathione S-transferase activities and isoenzyme expression, metallothionein levels and P-glycoprotein expression in normal ovaries, and in epithelial ovarian tumor biopsies from patients prior to chemotherapy or following relapse. These parameters have been implicated as determinants of response to cytotoxic chemotherapy. Large differences were found between normal ovary and ovarian tumors, but no significant differences were observed between tumors taken before or after cytotoxic chemotherapy. These data do not support a role for these biochemical parameters in the decreased response seen in patients with recurrent or progressive disease.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 4 (1994), S. 0 
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Carcinosarcomas (previously termed malignant mixed Müllerian tumors) are highly malignant but rare tumors of the ovary. Most patients have been treated according to a wide variety of protocols for soft tissue sarcoma or for epithelial ovarian carcinoma and as a result the optimal treatment for this neoplasm is unknown. We describe here 20 patients with this ovarian tumor (15 with heterologous sarcomatous elements and five with homologous sarcomatous elements) referred to our institute. Five patients were treated with surgery alone, two patients with chemotherapy alone and 13 patients with a combination of surgery and chemotherapy. A variety of chemotherapeutic regimens were used reflecting the 10-year time span it took to accrue these patients. Forty-five per cent of all patients died within 1 year of initial surgery and there was a median survival of 14 months. Two patients achieved a complete remission following treatment with 10 cycles of intravenous cyclophosphamide and are still alive at 103 and 106 months follow-up. We suggest that a chemotherapy regimen combining cyclophosphamide and a platinum analog may be useful for the management of patients with carcinosarcoma of the ovary requiring further therapy following surgery.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Urinary and plasma amines and amine metabolites were quantified in two individuals with Norrie disease resulting from a deletion in chromosomal region Xp 11.3, recently reported to be associated with absence of the gene encoding monoamine oxidase (MAO)-A and nondetectable MAO-A activity in fibroblasts and MAO-B activity in platelets. Marked (four- to 100-fold) elevations in levels of urinary phenylethylamine, o-tyramine, and m-tyramine (which are preferential substrates for MAO-B) and marked reductions (90%) in levels of 3-methoxy-4-hydroxyphenylglycol (a deaminated metabolite of norepinephrine, a preferential substrate for MAO-A) in urine and plasma confirmed the presence of a systemic, functionally significant reduction in the activities of both MAO isozymes. The magnitude of these changes, which are equivalent to those found in subjects taking MAO-inhibiting antidepressants, suggests that early initiation of dietary and drug restrictions may be clinically important in these and other patients with X-chromosomal mutations involving MAO. These findings further support the proposition that the MAOA and MAOB genes are located in close proximity on the X chromosome. Negligible changes in the metabolites of dopamine and serotonin raise the possibility that other metabolic pathways are of importance for their production, that dietary or intestinal bacterial sources contribute substantially to the presence of these amine metabolites in urine, or both.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 102 (1995), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective To examine the management of cord prolapse and its morbidity and mortality.Design Retrospective study of consecutive babies born after cord prolapse, identified using the Oxford Obstetric Data System, and those with registered handicap, identified by the Oxford Region Register of Early Childhood Impairments.Setting District maternity hospital managing more than 6000 deliveries annually.Subjects One hundred and thirty–two babies born after the identification of cord prolapse in the John Radcliffe Hospital between January 1984 and December 1992.Main outcome measures Survival rates, condition at birth assessed by Apgar scores at 1 and 5 minutes and blood gas values on cord blood samples, and incidence of major handicap at three years of age.Results The incidence of cord prolapse was 1 in 426 total births. There were six stillbirths and six neonatal deaths. One baby died as a result of birth asphyxia. The uncorrected perinatal mortality rate was 91 per 1000. Of 120 survivors, only one baby was known to suffer a major neurological handicap. Electronic cardiotocographs aided the diagnosis of cord prolapse in 41 % of cases. Apgar scores were better with a shorter diagnosis to delivery interval, but cord gas results did not correlate well with Apgar scores or the diagnosis to delivery interval.Conclusions Cord prolapse occurs with a relatively stable incidence in this population irrespective of changes in obstetric practices. Despite the high incidence of ominous cardiotocographs, low Apgar scores and acidaemia on blood gas analysis, the fetal outcome is not as poor as might be expected and mortality is predominantly attributable to congenital anomalies and prematurity rather than birth asphyxia.
    Type of Medium: Electronic Resource
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