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  • 1
    Electronic Resource
    Electronic Resource
    Time-resolved dissociative intense-laser field ionization for probing dynamics: Femtosecond photochemical ring opening of 1,3-cyclohexadiene (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 8347-8362 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The concerted photochemical ring opening of 1,3-cyclohexadiene was investigated in the gas phase by low-intensity pumping at 267 nm and subsequent probing by high-intensity photoionization at 800 nm and mass-selective detection of the ion yields. We found five different time constants which can be assigned to traveling times along consecutive parts of the potential energy surfaces. The molecule is first accelerated in the spectroscopic state 1B along Franck–Condon active coordinates, then alters direction before changing over to the dark state 2A. All constants including that for leaving the 2A surface are below 100 fs. These times are shorter than appropriate vibrational periods. Such a maximum speed is evidence that the pathway is continuous leading from surface to surface via real crossings (conical intersections) and that the molecule is accelerated right into the outlet of the 2A/1A funnel. On the ground state it arrives as a compact wave packet, indicating a certain degree of coherence. The experimental method promises a high potential for investigating dynamics, since many consecutive phases of the process can be detected. This is because the fragmentation pattern depends on the location on the potential energy surface, so that monitoring several different ions permits to conclude on the population flow through these locations. Ionization at the intensities used is normally considered to be an effect of the electric field of the radiation. But in our case it is enhanced by resonances in the neutral molecule and in particular in the singly positive ion, and it is not sensitive for the length of the molecule (different conformers of the product hexatriene). The ionic resonances explain why hexatriene has a much richer fragmentation pattern than cyclohexadiene. Coulomb explosion is observed from an excited state of a doubly positive ion. Its mechanism is discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481478
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  • 2
    Electronic Resource
    Electronic Resource
    Analysis of longitudinal mode wave guiding in vertical-cavity surface-emitting lasers with long monolithic cavity (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 586-588 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Lasing mode switching between two longitudinal modes is observed in transverse single mode vertical-cavity surface-emitting lasers with an extended cavity. Near- and far-field analyses carried out on devices with 2, 4, and 8 μm cavity spacers show an inherent relation between the transverse mode diameter and the calculated oxide- or thermally induced index guiding for the oscillating modes. Depending on the designed alignment of the optical longitudinal standing wave patterns relative to the oxide layer, mode switching can either be promoted or suppressed. Record-high single mode output powers up to 5.5 mW obtained from devices with 8 μm spacers and 8μm active diameter indicate the potential of the given device concept for low-divergence fundamental mode emission as required for many applications. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1344569
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  • 3
    Electronic Resource
    Electronic Resource
    Eine einfache Synthese aller vier stereoisomeren 2,2,5-Trimethyl-1,3-dioxolan-4-carbaldehyde (1994)
    Springer
    Monatshefte für Chemie 125 (1994), S. 763-771 
    Details
    ISSN: 1434-4475
    Keywords: 2,2,5-Trimethyl-1,3-dioxolane-4-carbaldehydes ; aldopentose diethyl dithioacetals ; lead tetraacetate cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and efficient procedure for the syntheses of all four stereoisomers of the 2,2,5-trimethyl-1,3-dioxolane-4-carbaldehydes1a–1d has been developed. Starting with readily available aldopentose diethyl dithioacetals2,6,10 and14, the title compounds were obtained by a selective protecting group strategy and subsequentRaney-nickel reduction, followed by lead tetraacetate cleavage. This procedure allows an application on a multigram scale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01277638
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  • 4
    Electronic Resource
    Electronic Resource
    Triploidie als Ursache von Schwangerschaftsgestose im 2. Trimenon (1975)
    Springer
    Archives of gynecology and obstetrics 218 (1975), S. 113-123 
    Details
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ein Fall von kindlicher Triploidie wird vorgestellt. Die Schwangerschaft war gekennzeichnet durch therapieresistente EPH-Gestose im 2. Trimenon mit Übergang in Präeklampsie in der 33. Woche. Der durch Sectio entbundene, nicht lebensfähige Fetus war äußerlich weiblich, untergewichtig, hypoton und asphyktisch. Er wies eine Hirnmißbildung mit Kebozephalie, einem großen univentrikulären Hohlraum und Fehlen der Hypophyse sowie multiple Mißbildungen und dysmorphe Zeichen auf. Bei der Sektion fanden sich Hypo- und Dysplasie der Nebennieren; Uterus, Tuben und Ovarien waren nicht angelegt, Testes waren nicht nachweisbar. Die Plazenta war auffallend groß und zeigte herdförmige hydatidiforme Degenerationen der Zotten. Der Karyotyp war 69,XXY, und mit Hilfe der Fluoreszenzmarker ließ sich der väterliche Ursprung des überzähligen haploiden Satzes nachweisen. Die für Triploidie typischen Schwangerschaftsbefunde werden besprochen und auf die Möglichkeit der pränatalen Diagnose durch Chromosomenuntersuchung an gezüchteten Zellen der Amnionflüssigkeit wird hingewiesen.
    Notes: Summary The authors report a case of triploidy in a prematurely born child. The pregnancy was complicated by severe toxemia beginning during the second trimester and terminating in preeclampsia leading to cesarian section in the 33th week of gestation. The externally female child was underweight, hypotonic and asphyctic and died shortly after birth. She exhibited a complex brain malformation including excessive hydrocephaly, cebocephaly and aplasia of the piturary gland, and multiple dysmorphic signs. Autopsy revealed hypoplasia and dysplasia of the adrenal glands; no uterus, tubes and ovaries were present, but no testes were found. The placenta showed localized hydatidiform degeneration and was relatively large. The karyotype was 69,XXY, and with the aid of fluorescence markers, paternal origin of the additional haploid chromosome set was demonstrated. Typical findings in pregnancies with fetal triploidy are discussed and the possibility of prenatal diagnosis of triploidy by chromosome analysis in cultivated amniotic fluid cells is pointed out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01395911
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  • 5
    Electronic Resource
    Electronic Resource
    Plan for the swiss randomized hail suppression experiment. Design of Grossversuch IV (1978)
    Springer
    Pure and applied geophysics 117 (1978), S. 548-571 
    Details
    ISSN: 1420-9136
    Keywords: Hail prevention ; Randomized seeding ; Statistical design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract An experimental research program is described which investigates the possibility of reducing hailfall in an area of 1000 km2 using the Moldavian rocket seeding method. It involves a design in which experiments are randomized (50∶50) by day over a fixed experimental area. The evaluation is based on data collected during the experimental unit (12–2100 hours). The test variable is hail kinetic energy measured by hailpads and by a hailpad-adjusted S-band radar. A description of the experimental area, the instrumentation and the seeding method adapted from the Soviet Union as well as calculations of the nuclei plume behaviour after seeding with large Oblako rockets are presented. The statistical design is given as well as an extensivea priori description of the confirmatory evaluation procedure which will be used to prove an eventual seeding effect. It is recognized that good predictors are essential to arrive at a statistically significant results in 5 years. From synoptic and radar data obtained during the preliminary phase of the experiment a predictor function is derived. A concomitant variable (cloud base temperature) is proposed taking into account a possibly variable reaction of different storm types to the seeding. The development of the statistical test to be used is also described. Section 7 indicates some possibilities for further exploratory analyses with emphasis on hailpad measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876634
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  • 6
    Electronic Resource
    Electronic Resource
    IR absorption of highly vibrationally excited SF6 (1978)
    Springer
    Applied physics 15 (1978), S. 297-301 
    Details
    ISSN: 1432-0630
    Keywords: 33
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In a double-resonance experiment, the absorption of various CO2 laser lines by sulfur hexafluoride was measured, before and after the SF6 was pumped by a fixed frequency CO2 laser to a level of 5 quanta/molecule. The absorption is substantially shifted to longer wavelengths. But the short wavelength wing of the absorption band is not completely bleached. Instead a shoulder of several cm−1 width is left. This shoulder is probably important for the explanation of the infrared laser induced dissociation of SF6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00896111
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  • 7
    Electronic Resource
    Electronic Resource
    High amniotic fluid alpha-1-fetoprotein in a case of fetal sacrococcygeal teratoma (1975)
    Springer
    Human genetics 〈Berlin〉 26 (1975), S. 353-354 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Amniocentesis was performed in a pregnancy of 26 weeks because of hydramnios. The amniotic fluid was examined for fetal karyotype and AFP content. The latter was elevated to 300 μg/ml. Fetal death occurred shortly after amniocentesis and a malformed male fetus with a large sacrococcygeal teratoma was stillborn 3 days later.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285387
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  • 8
    Electronic Resource
    Electronic Resource
    Structural aberrations of chromosome 18 (1975)
    Springer
    Human genetics 〈Berlin〉 26 (1975), S. 123-132 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenjassung 3 Patienten mit dem 18q — Syndrom, 2 Knaben und 1 Mädchen, werden vorgestellt und mit den Fällen der Literatur verglichen. Die folgenden typischen Merkmale des 18q — Syndroms fanden sich bei ihnen: Kleinwuchs, Schwachsinn, muskuläre Hypotonie, Gesichts- und Ohrdysmorphie, Kryptorchismus bei den Knaben sowie zurückversetzte Daumen, konisch zulaufende Finger, Häufung von Wirbelmustern auf den Fingerbeeren und nach dorsal versetzte 2. Zehen. 2 Patienten zeigten die für das 18q — Syndrom typische Mittelgesichtsdysplasie sowie Hypertelorismus und Strabismus, hingegen wiesen alle drei Nystagmus und eine charakteristische Ohrdysmorphie mit Vortreten von Anthelix und Antitragus auf. Je 2 Patienten waren schwerhörig bzw. hatten auffallend enge Gehörgänge. Bei einem Fall fanden sich noch ein Iris- und Chorioideakolobom, Opticusatrophie und eine Lippenspatle, bei einem anderen eine Nabel- und Leistenhernie. Bei 2 Patienten war die Deletion des langen Arms von Chromosome 18 neu entstanden, bei einem war der Vater Träger einer balancierten Translokation t(15;18)(q24;q21).
    Notes: Summary 3 cases of the 18q — syndrome, 2 boys and 1 girl, are presented, and a comparison with data from the literature is given. The following features are typical of the syndrome: short stature, mental retardation, muscular hypotonia, a peculiar dysmorphia of the face and ears, cryptorchidism and small scrotum in males, proximally implanted thumbs, tapering fingers, excess of whorls on the fingertips, and dorsally implanted second toes. Midface hypoplasia with hypertelorism and cleft palate, as well as strabismus, were present in 2 of our patients, whereas all 3 showed nystagmus and prominence of anthelix and antitragus. In addition, 2 patients exhibited narrow ear canals and impaired hearing. One patient had coloboma of the iris and choroid, pale optic discs, and cleft lip; another had umbilical and inguinal hernias. Two cases represented de novo deletions of the long arm of chromosomes 18, whereas the karyotype of the father of the third case revealed a balanced translocation t(15;18)(q24;q21).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00278439
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  • 9
    Electronic Resource
    Electronic Resource
    Tandem duplication q14 and dicentric formation by end-to-end chromosome fusions in ataxia telangiectasia (AT) (1975)
    Springer
    Human genetics 〈Berlin〉 30 (1975), S. 135-141 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Chromosome studies on lymphocyte cultures were performed in 5 patients with AT, 2 of whom had been followed for 4 years. Four out of these patients showed an increased incidence of chromosome-type aberrations. A clonal development was present in one patient, 96% of his metaphases containing a tandem duplication of almost the entire long arm 14. Four years earlier the proportion of these cells was 80%. Two other patients presented a small proportion of cells with an unidentified abnormally long D chromosome. In a total of 724 metaphases from 4 patients 31 dicentric chromosomes were observed, all of a peculiar type: in their formation no chromosome material was lost and they all seem to have arisen by end-to-end fusions. The incidence of chromatid-type aberrations was normal or at the upper limit of control values in all 5 cases. The sister chromatid exchange rate studied with BUDR in 3 patients was found to be normal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00291946
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  • 10
    Electronic Resource
    Electronic Resource
    Trisomy 9p due to paternal translocation, t(9;13)(q13;q12) (1975)
    Springer
    Human genetics 〈Berlin〉 30 (1975), S. 307-316 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A 16-year-old girl with trisomy 9p is described. She had a short stature, severe mental retardation and the following abnormal clinical findings: peculiar face with hypertelorism, downward slanting palpebral fissures, convergent strabismus, a bulbous nose with broad and prominent bridge, short upper lip, narrow, high-arched palate; short neck with low hairline; severe kyphoscoliosis and a congenital clubfoot deformity; hypoplasia and dysplasia of several phalanges of the fingers and toes and some nails, a delay by about 6 years in bone age, and remarkable dermatoglyphic patterns. The father and 3 other family members carried a balanced translocation between chromosomes 9 and 13, t(9;13)(q13;q12).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275143
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