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  • 1
    Electronic Resource
    Electronic Resource
    Biparietal diameter and crown-rump length in fetuses with Down's syndrome: implications for antenatal serum screening for Down's syndrome (1993)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 100 (1993), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives 1. To compare the ultrasound biparietal diameter and crown-rump length of fetuses with and without Down's syndrome in the first half of pregnancy; 2. To investigate the effect of estimation of gestational age using either measure on the detection rate of serum screening for Down's syndrome.Design Matched case-control study. Cases were singleton Down's syndrome pregnancies with a biparietal diameter or a crown-rump length recorded. Five controls were matched to each case on: medical centre; the date of the ultrasound scan examination (within two years); gestational age measured as the number of days since the first day of the last menstrual period; and the ultrasound measure used (ie the biparietal diameter (the measure of choice), or the crown-rump length otherwise). If a woman had a serum screening test for Down's syndrome, the biparietal diameter or crown-rump length measurement had to be taken prior to the screening test so that the result of the test could not influence whether a scan was performed.Setting Ten antenatal screening centres in seven countries in Europe and North America.Subjects Two hundred and one women with singleton Down's syndrome pregnancies and 1005 women with unaffected singleton pregnancies.Results The median biparietal diameter of fetuses with Down's syndrome was identical to that among the controls (median difference 0.0mm, 95% confidence intervals (CI)–0.5 to 0.5mm). The estimates of gestational age based on biparietal diameter yielded a median gestational age less than that based on the women's last menstrual period: three days less for cases and two days less for controls; small but statistically significant differences probably reflected a minor systematic difference in the conversion of a biparietal diameter to a gestational age estimate. The median crown-rump length of fetuses with Down's syndrome was also identical to that among controls (median difference 0.0mm, 95% CI–1.5 to 2.0 mm). There was no significant difference between the median gestational age estimate based on crown-rump length and that based on the women's last menstrual period.Conclusion In antenatal screening for Down's syndrome the routine use of an ultrasound biparietal diameter or crown-rump length measurement to estimate gestational age will not adversely affect the detection rate. To avoid differences in gestational age estimates using the last menstrual period and the biparietal diameter influencing screening performance, separate medians should be derived for each serum marker using the two methods of estimating gestational age. The appropriate set of medians can then be used to calculate the multiple of the median value for each woman screened depending on the method used to estimate her gestational age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1993.tb15267.x
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  • 2
    Electronic Resource
    Electronic Resource
    Maternal serum screening for Down's syndrome: the effect of routine ultrasound scan determination of gestational age and adjustment for maternal weight (1992)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 99 (1992), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective To investigate the effect of using a routine ultrasound estimate of gestational age and maternal weight adjustment on maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3) and human chorionic gonadotrophin (hCG) levels in antenatal screening for Down's syndrome.Design Women with a singleton pregnancy without Down's syndrome were screened using the three serum markers and an estimate of gestational age based on ‘dates’ (time since first day of the last menstrual period) and one based on an ultrasound scan examination was recorded together with maternal weight.Setting Women attending the Homerton Hospital, Hackney, for their antenatal care between February 1989 and January 1990.Subjects 2113 women with a singleton pregnancy without Down's syndrome.Results The use of ultrasound to estimate gestational age (usually based on the biparietal diameter of the fetal skull) led to a significant reduction in the variance of each marker at a given week of pregnancy. The level of each marker was negatively associated with maternal weight, so that adjustment for weight also led to a reduction in variance. These data on gestational age and maternal weight, taken together with published data on pregnancies associated with Down's syndrome, indicate that the routine use of ultrasound to estimate gestational age will increase the detection rate from 58% to 67% while maintaining the false-positive rate at 5%, or reduce the false-positive rate from 5.7% to 3.1% while maintaining the detection rate at 60%. Routine maternal weight adjustment for the serum marker levels was much less useful, increasing the detection rate by about 0.5% for a given false-positive rate, or reducing the false-positive rate about 0.1% for a given detection rate.Conclusion An ultrasound gestational age estimate available at the time of Down's syndrome screening confers a substantial advantage to screening performance with a further small benefit resulting from maternal weight adjustment, which is worth adopting if it can be done without difficulty or extra cost.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1992.tb14474.x
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  • 3
    Electronic Resource
    Electronic Resource
    Pseudo-symmetrical difluoroketones - Highly potent and specific inhibitors of HIV-1 protease
    Amsterdam : Elsevier
    FEBS Letters 329 (1993), S. 144-146 
    Details
    ISSN: 0014-5793
    Keywords: Anti-viral ; Difluoroketone ; HIV-1 ; Protease inhibitor
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-5793(93)80211-C
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  • 4
    Electronic Resource
    Electronic Resource
    Design of orally bioavailable, symmetry-based inhibitors of HIV protease
    Amsterdam : Elsevier
    Bioorganic and Medicinal Chemistry 2 (1994), S. 847-858 
    Details
    ISSN: 0968-0896
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0968-0896(00)82036-2
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  • 5
    Electronic Resource
    Electronic Resource
    Poly(fluoroalkoxyphosphazenes) - versatile seal materials (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 3185-3192 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(fluoroalkoxyphosphazene) fluoroelastomers are members of a new family of polymers based on a phosphorous-nitrogen backbone. Physical property evaluation tests have demonstrated that these fluorelastomers possess excellent stress-strain properties, low-temperature flexibility, thermal stability, and resistance to a variety of demanding environments including synthetic lubricants, hydrocarbon fuels, and aqueous caustics. Their service temperature range is about -60° -200°C. Poly(fluoroalkoxyphosphazene) fluoroelastomers have shown the capability to function in severe dynamic applications; i.e., lip seals (1⅞ in. I.D.) performed for 〉1000 hr at 5500 rpm in MIL L-7808G lubricant at 115°C. Also, O-ring seals successfully completed a 1000-hr dynamic qualification test over a temperature range of -54°-163°C in a rod seal test apparatus. These elastomers can be used for seals, O-rings, gaskets, diaphragms, hose, and protective coatings.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070211201
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  • 6
    Electronic Resource
    Electronic Resource
    Poly(aryloxyphosphazenes) and a flame retardant foam (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 2575-2581 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Plastics and elastomers were prepared, physical state determined by the side chains attached to the phosphorus-nitrogen backbone. The poly(aryloxyphosphazenes) displayed a high degree of flame retardancy in the uncured, unfilled state. Limiting oxygen index (LOI) values varied from 27 to 33 for nonhalogenated materials and from 38 to 65 for halogenated materials. These values qualify all poly(aryloxyphosphazenes) studied as flame retardants according to the generally accepted definition (LOI ≥ 27). Materials subjected to the National Bureau of Standards Smoke Test gave encouraging results. The [(C6H5O)2PN-(4-C2H5C6H4O)2PN]n elastomer was investigated for application as a fire retardant insulating foam. Closed-cell foams produced from this copolymer showed much improved fire retardancy and smoke generation compared to commercially available fire retardant foam insulations.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210923
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