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  • 1
    Electronic Resource
    Electronic Resource
    Id helix-loop-helix proteins are differentially expressed in gestational trophoblastic disease (2005)
    Oxford, UK : Blackwell Science Ltd
    Histopathology 47 (2005), S. 0 
    Details
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aims : To assess the expression of Id proteins in trophoblastic tissues and to correlate this with clinical parameters, proliferative and apoptotic indices as well as to related oncogene expression.Methods and results : Immunohistochemistry for Id1, Id2, Id3 and Id4 was performed on 83 trophoblastic tissues including 17 normal first-trimester placentas, seven term placentas, 47 hydatidiform moles (HM), and 12 spontaneous miscarriages. The four Id proteins were predominantly expressed in the villous and implantation site intermediate trophoblast. Expression of Id1 in HM was significantly higher than that in normal placenta (P = 0.0006) and spontaneous miscarriage (P = 0.0001) but did not correlate with subsequent development of gestational trophoblastic neoplasia (GTN). Id1 expression correlated with the proliferation index as assessed by MCM7 (P = 0.003) and Ki67 (P = 0.017) and with the apoptotic activity assessed by TUNEL (P = 0.001) and M30 CytoDeath antibody (P = 0.013). Moreover, the expression of Id1 correlated with the expression of p53 (P = 0.004), p21WAF1/CIP1 (P = 0.003) but not with p16 (P = 0.107).Conclusions : Id proteins may play a role in the regulation of proliferative and apoptotic activity in trophoblastic tissue and are potentially useful in differentiating molar and non-molar gestation, but are not helpful in predicting GTN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2559.2005.02190.x
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  • 2
    Electronic Resource
    Electronic Resource
    Annealing studies of low-temperature-grown GaAs:Be (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1699-1707 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The isochronal and isothermal annealing characteristics of acceptor-doped GaAs:Be grown at low substrate temperatures (300 °C) by molecular-beam epitaxy (LTMBE) have been studied. The Be was introduced in a range of concentrations from 1016 to 1019 cm−3. Electrical measurements of as-grown material up to the highest Be concentration of 1019 cm−3 show that no free holes are contributed to the valence band even though Raman spectroscopy of the Be local vibrational mode indicates that the majority of the Be impurities occupy substitutional sites. It is proposed that Be acceptors are rendered inactive by the high concentration of AsGa-related native donor defects present in LTMBE material. The concentration of AsGa-related defects in the neutral charge state was estimated from infrared absorption measurements to be as high as 3×1019 cm−3. A distinct annealing stage at 500 °C, similar to that found in irradiation-damaged and plastically deformed GaAs, marks a rapid decrease in the concentration of AsGa-related defects. A second annealing stage near 800 °C corresponds to the activation of Be acceptors. The presence of gallium vacancies VGa was investigated by slow positron annihilation. Results indicate an excess concentration of VGa in LTMBE layers over bulk-grown crystals. Analysis of isothermal annealing kinetics for the removal of AsGa-related defects gives an activation energy of 1.7±0.3 eV. The defect removal mechanism is modeled with VGa-assisted diffusion of AsGa to As precipitates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351200
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  • 3
    Electronic Resource
    Electronic Resource
    The role of dislocation-dislocation interactions in the relaxation of pseudomorphically strained semiconductors. II. Experiment−The high-temperature relaxation of ultrahigh-vacuum chemical-vapor-deposited SiGe thin films (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 4820-4825 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermal relaxation of SiGe films deposited by ultrahigh-vacuum chemical vapor deposition was studied by annealing the films for times up to 21/2 h at a temperature of 950 °C. Strain relaxation was determined by misfit dislocation density obtained by planar-view transmission electron microscopy and by double-crystal x-ray diffractometry. When the relaxation process requires relatively few dislocations ((approximately-less-than)2 μm), the films relax to a remnant strain which is in agreement with previous experimental measurements; however, when higher densities of misfit dislocations were generated, substantially larger remnant strains were observed. This is interpreted as resulting from energetic interactions among the dislocations and analyzed in terms of the theory developed previously. It is found that the cutoff distance for dislocation interactions is substantially greater than the film thickness and a value of 1.4±0.5 μm is determined for 75–150-nm-thick films. Limited data from the literature also indicate a cutoff distance that is substantially in excess of the film thickness. In addition, as the annealing time is increased, a marked propensity for dislocation banding is observed, attesting to the mixed nature (attractive and repulsive) of the interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350624
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  • 4
    Electronic Resource
    Electronic Resource
    Annealing kinetics of a-Si:H deposited by concentric-electrode rf glow discharge at room temperature (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 1826-1831 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The irreversible isothermal annealing of the as-deposited defects of hydrogenated amorphous silicon, a-Si:H, deposited at room temperature by concentric-electrode radio-frequency glow discharge is studied using dark and photoconductivity, space-charge limited current, and time-of-flight. The photoconductivity increases as a power law of the annealing time with exponent 0.8. The density of states at the Fermi level, measured by space-charge limited current, is inversely proportional to the annealing time. These results are compatible with bimolecular annealing kinetics. The dark conductivity obeys a Meyer–Nelder rule during the isothermal anneal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353167
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  • 5
    Electronic Resource
    Electronic Resource
    The role of dislocation-dislocation interactions in the relaxation of pseudomorphically strained semiconductors. I. Theory (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 4814-4819 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The role of dislocation-dislocation interactions on the relaxation behavior of biaxially stressed semiconductor thin films is considered by including interaction terms in an energy minimization. Both parallel and crossing interactions are considered and energies are calculated for orthogonal arrays of equally spaced 60° misfit dislocations, and it is shown that the parallel interactions can be either attractive or repulsive. The equilibrium misfit dislocation density is shown to be a function of the "cutoff'' distance for dislocation interactions in these structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350623
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  • 6
    Electronic Resource
    Electronic Resource
    Deposition of amorphous silicon using a tubular reactor with concentric-electrode confinement (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 3981-3989 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High-quality, hydrogenated amorphous silicon (a-Si:H) is deposited at room temperature by rf glow discharge at a high deposition rate using a tubular reactor with cylindrical symmetry (concentric-electrode plasma-enhanced chemical vapor deposition, CE-PECVD). Using the novel CE-PECVD design, room-temperature deposition of a-Si:H with growth rates up to 14 A(ring) s−1, low hydrogen concentration ((approximately-less-than)10%), and the bonded hydrogen in the Si-H monohydride configuration, is achieved for the first time using an rf glow-discharge technique. The influence of the deposition parameters (silane flow rate, pressure, and power density) on the growth rate, optical band gap, and silicon-hydrogen bonding configuration, is quantitatively predicted using a deposition mechanism based on the additive contribution of three growth precursors, SiH2, SiH3, and Si2H6, with decreasing sticking coefficients of 0.7, 0.1, and 0.001, respectively. The low hydrogen concentration is due to the enhanced ion bombardment resulting from the concentric electrode design.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350870
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of the flow of silane on the properties of a-Si:H deposited by concentric-electrode radio frequency glow-discharge (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 3990-3996 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High band gap, device-quality, hydrogenated amorphous silicon (a-Si:H) was deposited from silane at room temperature using concentric-electrode plasma-enhanced chemical vapor deposition (CE-PECVD). Increasing the flow of silane from 15 to 99 sccm resulted in a continuous increase of the optical band gap, Eopt, from 1.7 to 2.1 eV, and changed the dominant bonding configuration from Si-H to Si-H2. The total hydrogen concentration as determined from the integrated absorption of the SiHx stretching bond increased from 7% to 15%. As Eopt varied between 1.7 and 2.1 eV, the photoconductivity, σph, decreased from 10−5 to 10−7 Ω−1 cm−1 and the dark conductivity, σd, dropped from 10−10 to 10−14 Ω−1 cm−1 (σph and σd measured at room temperature after a 1 h anneal at 200 °C). These results are superior to those obtained using a-SiC:H alloys deposited under comparable conditions (i.e., without hydrogen dilution). After annealing, three different conduction paths were identified and correlate with the silicon-hydrogen bonding configuration. The photosensitivity of high band gap a-Si:H films, σph/σd, follows Slobodin's rule for a-SiGe:H alloys. High band gap a-Si:H deposited by CE-PECVD has significant potential to challenge the role of a-SiC:H as the choice material for films with 1.7 (approximately-less-than) Eopt (approximately-less-than) 2.1 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350871
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  • 8
    Electronic Resource
    Electronic Resource
    Photoluminescence study of the growth of indium phosphide by metalorganic chemical vapor deposition (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 5486-5492 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The growth of unintentionally doped indium phosphide by low pressure metalorganic chemical vapor deposition (LPMOCVD) using triethlylindium and phosphine has been investigated by low temperature photoluminescence (PL). Pregrowth annealing was found to result in improved crystalline quality of the seed surface. The predominant acceptor impurity on the annealed substrate surface and in the initial epitaxial region (1200 A(ring)) was shown to be carbon. The major acceptor impurity in thicker epilayers further away from the substrate interface was determined to be Zn. Silicon was also identified from the PL spectra, though its concentration might be much smaller than that of zinc. No deep level impurities were observed in this material. Most important of all, the highly resolved exciton PL spectrum demonstrated that excellent quality InP comparable to the best material grown by vapor phase epitaxy could be grown by LPMOCVD without the need for phosphine cracking.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.335460
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  • 9
    Electronic Resource
    Electronic Resource
    The application of flow cytometric DNA analysis in detecting the presence of malignant cells in ovarian carcinoma peritoneal fluids (1995)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 102 (1995), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective To compare flow cytometric detection of malignant cells with standard cytological evaluation in patients with ovarian carcinoma.Setting The City Hospital Trust, The Women's Hospital and CRC Trials Unit, Birmingham.Subjects Forty-three patients with histologically proven ovarian carcinoma and positive cytology, and a control population of 20 patients undergoing surgery for benign gynaecological conditions.Methods Prospective, blinded study examining ascitic fluid or peritoneal washings obtained at primary surgery by flow cytometric DNA analysis and cytological examination.Results Flow cytometry detected aneuploid cells in 27/43 (63%) of malignant and 7/20 (35%) of benign fluid specimens. In malignant samples the mean aneuploid count was 38.5% (range 1–98%) with a mean S-phase fraction of 5.2% (range 0–33.9%). In benign specimens the mean aneuploid count was 30.4% (range 14.5–66.4%). Based on these results, the overall sensitivity of cytometric detection of malignant cells was 714Y0, specificity 65%, with a positive predictive value of 85.1%. False positivity was found mainly in patients with benign ovarian cysts. Further examination revealed four false negative and four false positive results, where the peritoneal fluid and ovarian tissue DNA ploidy status concurred. Assuming such results to be correct increased the sensitivity of the test to 88.5YO and specificity to 85%.Conclusions Although flow cytometry can glean information beyond the capabilities of cytological assessment, using the premise that aneuploid cells alone indicate malignancy, it remains secondary to cytology in the detection of malignant cells in peritoneal fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1995.tb11406.x
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  • 10
    Electronic Resource
    Electronic Resource
    Serial urinary cyclic guanosine monophosphate measurements in the assessment of response to treatment in epithelial ovarian cancer (1987)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 94 (1987), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Serial measurements of urinary cyclic guanosine monophosphate (cGMP) were performed in 47 patients with epithelial ovarian cancer. In 30 patients, the pre-chemotherapy cGMP level was above the range for normal controls (marker positive); the remainder were within the normal range. Marker positive patients demonstrated a 96% correlation of disease regression with a fall in marker level and a 75% correlation of disease progression with a rise in marker level. The corresponding correlations in the marker negative group were 41% and 39%. Marker positive patients also demonstrated a rise in marker before clinical recognition of disease progression in six of 11 instances whereas only one of nine instances in marker negative patients showed such a rise. Patients with evidence of static disease had normal and stable marker levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1987.tb03126.x
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