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  • 1
    Electronic Resource
    Electronic Resource
    Activation status of the X chromosome in human micronucleated lymphocytes (1996)
    Springer
    Human genetics 〈Berlin〉 97 (1996), S. 471-475 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The frequency of X chromosome aneuploidy in human female peripheral blood lymphocytes has been reported by several investigators to be significantly higher than expected based upon chance alone. Studies in our laboratory showed that 72% of the micronuclei in the peripheral blood of human females contained the X chromosome. Such a high frequency of X chromosome loss suggests that some unique mechanism may be responsible for this phenomenon. The present study was carried out to test the hypothesis that the lost or micronucleated chromsome is the inactive and not the active X. Blood samples were obtained from two unrelated females, 36 and 33 years of age, each with a different X; 9 reciprocal translocation. In each, the normal X chromosome is inactive and the translocated X is active. Isolated lymphocytes were cultured according to standard techniques and blocked with cytochalasin B. Using a modified micronucleus assay, we scored 10,000 binucleated cells from the 36 year old, while 9,500 binucleated cells were scored from the 33 year old. The slides were first labeled and the kinetochore status of each micronucleus was determined. This was followed by simultaneous hybridization with a 2.0 kilobase centromeric X chromosome-specific probe and a chromosome 9 specific whole chromosome painting probe. All micronucleated cells were relocated and scored for their probe status. A total of 217 micronuclei were scored from the two subjects, of which 96 (44.2%) contained the X chromosome. Of these 96 micronuclei, 80 (83.3%) contained the inactive X, based on the absence of chromosome 9 material in the micronucleus. These results support our hypothesis that the inactive X chromosome is preferentially included in the micronuclei, and suggest that the X chromosome hypoploidy observed at metaphase in aging women is a related phenomenon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390050075
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen loss during thermal donor formation in Czochralski silicon: New insights into oxygen diffusion mechanisms (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 1427-1442 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: As-grown Czochralski silicon samples with different oxygen concentrations have been heated at temperatures in the range 350–500 °C. Oxygen loss during anneals at low temperatures (T≤400 °C) is shown to follow second-order kinetics and measurements led to values of oxygen diffusivity that were larger than normal by a factor of ∼3, assuming the capture radius for dimer formation was 5 A(ring). Variations in the rate of [Oi] loss during more extended anneals could be explained if oxygen diffusion was initially enhanced but tended to its normal value as the anneals progressed. Much greater initial enhancements were derived from similar measurements for samples which had been hydrogenated by a heat treatment in H2 gas at 1300 °C for 30 min followed by a rapid quench to room temperature, and the enhancements were consistent with values derived from measurements of the relaxation of stress-induced dichroism. At higher temperatures (T≥450 °C) the measured rates of [Oi] loss were less than the expected rate of Oi-Oi interaction and tended to vary with increasingly high powers of [Oi]. Modeling of the clustering process demonstrated that the reductions could be explained if the oxygen dimers were present in a quasiequilibrium concentration throughout the anneals. The establishment of this equilibrium appears to require that oxygen dimers diffuse much more rapidly than isolated Oi atoms. The kinetics of oxygen loss over the whole range of temperatures can then be explained if dimer clustering leads mainly to increases in concentrations of agglomorates containing large numbers (≥8) of oxygen atoms. It is therefore possible to account for thermal donor (TD) formation based on the formation of different sizes of oxygen clusters, although the possibility that self-interstitials are involved in TD formation is not excluded. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358890
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  • 3
    Electronic Resource
    Electronic Resource
    Nanoscale oxide patterns on Si(100) surfaces (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 976-978 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ultrathin oxide patterns of a linewidth of 50 A(ring) have been created on Si(100)-2×1 surfaces by a scanning tunneling microscope operating in ultrahigh vacuum. The oxide thickness is estimated to be 4–10 A(ring). The morphology and spectroscopy of the oxide region are obtained. Hydrogen passivation is used as an oxidation mask. The defects caused by oxidation in the passivated region before and after the hydrogen desorption are compared and discussed. The multistep silicon processings by an ultrahigh vacuum scanning tunneling micropscope is thus demonstrated. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113817
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  • 4
    Electronic Resource
    Electronic Resource
    Novel aspects of oxygen diffusion in silicon (1996)
    Springer
    Journal of materials science 7 (1996), S. 347-353 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Normal diffusion of interstitial oxygen atoms (Oi ) accounts for the rate of oxygen aggregation in silicon for T 〉 500
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185929
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  • 5
    Electronic Resource
    Electronic Resource
    Activity banding of human chromosomes as shown by histone acetylation (1996)
    Springer
    Chromosoma 105 (1996), S. 41-49 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The expression of genes in mammalian cells depends on many factors including position in the cell cycle, stage of differentiation, age, and environmental influences. As different groups of genes are expressed, their packaging within chromatin changes and may be detected at the chromsomal level. The organization of DNA within a chromosome is determined to a large extent by the positively charged, highly conserved histones. Histone subtypes and the reversible chemical modifications of histones have been associated with gene activity. Active or potentially active genes have been associated with hyperacetylated histones and inactive genes with nonacetylated histones. Sodium butyrate increases the acetylation levels of histones in cell cultures and acts as both an inducer of gene activity and as a cell-cycle block. We describe a method to label the interphase distribution of DNA associated with various histone acetylation stages on chromosomes. Nucleosomes from untreated and butyrate-treated HeLa cells were fractionated by their acetylation level and the associated DNA labeled, and hybridized to normal human chromosomes. In the sodium butyrate-treated cells the resulting banding patterns of the high- and low-acetylated fractions were strikingly different. DNA from low-acetylated chromatin labeled several pericentric regions, whereas hybridization with DNA from highly acetylated chromatin resulted in a pattern similar to inverse G-bands on many chromsomes. The results from noninduced cells at both high and low acetylation levels were noticeably different from their induced counterparts. The capture and hybridization of DNA from interphase chromatin at different acetylation states provides a ”snapshot” of the distribution of gene activity on chromosomes at the time of cell harvest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004120050157
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  • 6
    Electronic Resource
    Electronic Resource
    Chromosomal localization and genomic organization of the human retinal rod Na-Ca+K exchanger (1998)
    Springer
    Human genetics 〈Berlin〉 103 (1998), S. 411-414 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The retinal rod Na-Ca+K exchanger is a unique calcium extrusion protein found only in the outer segments of retinal rod photoreceptors. Rod Na-Ca+K exchanger cDNA (NCKX1) has been cloned from bovine and human retinas. Here, we have used fluorescent in situ hybridization and radiation hybrid mapping to localize the human NCKX1 gene to chromosome 15q22. We have determined the genomic organization of human rod NCKX1 and found one intron in the 5’ untranslated region and eight introns within the coding region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390050842
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  • 7
    Electronic Resource
    Electronic Resource
    Laparoscopy in the evaluation and treatment of patients with AIDS and acute abdominal complaints (1997)
    Springer
    Surgical endoscopy and other interventional techniques 11 (1997), S. 1026-1028 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Acquired immunodeficiency syndrome — Acute abdomen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The evaluation of AIDS patients with acute abdominal complaints (AAC) is quite difficult, and surgical intervention is associated with a high complication rate. The intent of this study is to evaluate the application of laparoscopy in the diagnosis and treatment of AIDS patients with AAC. Methods: This is a retrospective analysis of 10 consecutive AIDS patients who presented with AAC. Each had evaluation by a surgical team with subsequent laparoscopic intervention. The charts were reviewed for age, sex, time with AIDS, AIDS comorbidities, evaluation modalities, findings, treatment modalities, and outcome. Results: Laparoscopy resulted in the successful surgical treatment of four patients, diagnosis of medically treatable conditions in four patients, and alteration of the incision site in the remaining two patients. Each patient thus received direct benefit from laparoscopy. Two complications, in the converted patients, and no mortalities were encountered. Conclusions: Laparoscopy is a safe and effective interventional modality in the diagnosis and treatment of AAC in the AIDS patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900517
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  • 8
    Electronic Resource
    Electronic Resource
    Laparoscopically assisted bowel surgery (1995)
    Springer
    Surgical endoscopy and other interventional techniques 9 (1995), S. 297-300 
    Details
    ISSN: 1432-2218
    Keywords: Bowel surgery ; Risk/benefit analysis ; Laparoscopic bowel surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to help determine the risks and benefits, we retrospectively analyzed the results of our first 114 laparoscopically assisted bowel procedures. Procedures performed consisted of partial colectomy (85), total or subtotal abdominal colectomy (8), total proctocolectomy with J-pouch ileal reservoir (11), and diverting procedures (10). Forty-nine procedures were for malignancy. The rate of conversion to laparotomy was 13.2%. Oral feedings were resumed in 2.4 days (range 1–5), and bowel function returned in 3.8 days (range 2–8). The average length of stay was 4.2 days for partial colectomy and 6 days for total, subtotal, and proctocolectomy. The mean return to normal activity for all groups was 16.7 days (10.8 days for partial colectomy). There were no deaths. Major morbidity (6%) consisted of abscess (3), anastomotic leak (2), and hemorrhage (1). Mean operative costs analyzed for the initial 37 patients were higher for laparoscopic colectomies when compared to traditional colectomies; however, the mean total hospital costs were less for the laparoscopic procedures. These data suggest that the laparoscopic approach to colorectal resection is an acceptable alternative to laparotomy for a variety of disease processes, allowing patients an early return to normal activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00187772
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  • 9
    Electronic Resource
    Electronic Resource
    Properties of C60 polymerized under high pressure and temperature (1997)
    Springer
    Applied physics 64 (1997), S. 231-2239 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 61.46.+w; 62.50.+p; 78.30.-j
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 60 polymers. Pure and mixed phase polymeric samples were synthesized by simultaneously subjecting microcrystalline C60 powder or pellets to various pressures ( \valunit{1}{GPa} 〈 P 〈 \valunit{4.8}{GPa} ) and temperatures ( \valunit{250}{\celsius} 〈 T 〈 \valunit{600}{\celsius} ). The optical spectra of the orthorhombic, tetragonal, and rhombohedral C60 polymer phases are observed to be quite distinct and rich. These spectra exhibit numerous lines and an overall downshift in frequency relative to C60 is observed, consistent with a loss of double bonds from the fullerene cage. The LDMS spectra of a sample synthesized at \valunit{2}{GPa} under hydrostatic conditions and \valunit{350}{\celsius} , exhibited a succession of \sim 12 clear peaks at mass numbers corresponding to (\chem{C_{60}})_{{N} = 1, 2\ldots 12} , similar to the LDMS data on the C60 photopolymer. This is taken as further evidence for interfullerene bonds in these high-pressure polymers. The XRD pattern of this sample indicates the presence of a strong texture in the sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050472
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  • 10
    Electronic Resource
    Electronic Resource
    Algebraic models of microprocessors Architecture and organisation (1996)
    Springer
    Acta informatica 33 (1996), S. 421-456 
    Details
    ISSN: 1432-0525
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract. We present an algebraic method for modeling microprocessors at different levels of abstraction, and for expressing the relationships between each level. We consider microprocessors at levels of abstraction determined by time and details of construction. The algebraic models isolate features of the scientific structure of microprocessor computation, providing: (i) a basis for modular decomposition of the description of microprocessors, including correctness criteria; and (ii) equational specification and verification techniques for the design of microprocessors relevant to a range of specification languages and theorem provers. Our specifications are iterated maps that decompose the modeling of the computer into easily understood, equationally specified stages, represented by algebras. We illustrate our algebraic tools with an example of a simple computer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002360050051
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