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  • 1995-1999  (5)
  • 1999  (5)
  • cloud point  (2)
  • 3‐dimethy‐2‐imidazolidinone solvent system  (1)
  • East China Sea  (1)
  • MR  (1)
Material
Years
  • 1995-1999  (5)
Year
  • 1999  (5)
Keywords
  • 1
    ISSN: 1572-882X
    Keywords: LiCl/1 ; 3‐dimethy‐2‐imidazolidinone solvent system ; homogeneous cellulose solution ; cellulose acetate ; O‐methylcellulose ; reaction characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In order to elucidate the nature of the LiCl/1,3‐dimethy‐2‐imidazolidinone (DMI) solvent system as one of the homogeneous reaction media of cellulose, cellulose acetate (CA) and O‐methylcellulose (MC) were prepared using this solvent system, and the distribution of substituents within anhydroglucose units was examined by 13C‐NMR. It was found that (i) homogeneous cellulose solutions can be easily prepared by heating 2, 5–12 and 100 parts of weight of cellulose, LiCl, and DMI, respectively, and (ii) the relative reactivity of hydroxyl groups is in the order C‐6 〉 C‐2 〉 C‐3 for both CA and MC. A remarkable feature of this solvent system is that the reaction efficiency in etherification is very high compared with other homogeneous solvent systems.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2161
    Keywords: Key words Knee ; anatomy ; Knee ; MR ; Knee ; ligaments ; menisci ; and cartilage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Purpose To demonstrate variations in the meniscofemoral ligaments (ligaments of Wrisberg and Humphrey) at anatomical study and magnetic resonance (MR) imaging. Design Twenty-eight cadaveric knees were partially dissected for the examination of the meniscofemoral ligaments. One hundred knee MR examinations were reviewed by two experienced musculoskeletal radiologists. Proximal variations in the meniscofemoral ligaments at MR imaging were classified into three types according to the attachment site: type I, medial femoral condyle; type II, proximal half of the posterior cruciate ligament (PCL); type III, distal half of the PCL. Distal variations were classified into vertical or oblique types according to the orientation of the intermediate signal at the interface of the ligament and lateral meniscus. Results At anatomical study, six cases showed variations in the proximal insertion site of the meniscofemoral ligaments. At MR imaging 93 cases had one or more meniscofemoral ligaments, giving a total of 107 ligaments: 90 ligaments of Wrisberg and 17 ligaments of Humphrey. Forty-one ligaments of Wrisberg were type I, 28 type II, 19 type III, and with two indeterminate type, while 6 ligaments of Humphrey were type I and the remaining 11 were indeterminate. Seven cases showed no meniscofemoral ligament. Of the 107 meniscofemoral ligaments, the distal insertion orientation was of vertical type in 10 ligaments, oblique type in 70 and unidentified in 27. Conclusion An understanding of the high incidence of meniscofemoral ligament variations may help in the interpretation of knee MR studies.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of oceanography 55 (1999), S. 257-270 
    ISSN: 1573-868X
    Keywords: Surface heat flux ; net heat flux ; Yellow Sea ; East/Japan Sea ; East China Sea ; monthly and annual means
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Based on the twice-daily marine atmospheric variables which were derived mostly from the weather maps for 18 years period from 1978 to 1995, the surface heat flux over the East Asian marginal seas was calculated at 0.5°×0.5° grid points twice a day. The annual mean distribution of the net heat flux shows that the maximum heat loss occurs in the central part of the Yellow Sea, along the Kuroshio axis and along the west coast of the northern Japanese islands. The area off Vladivostok turned out to be a heat-losing region, however, on the average, the amount of heat loss is minimum over the study area and the estuary of the Yangtze River also appears as a region of the minimum heat loss. The seasonal variations of heat flux show that the period of heat gain is longest in the Yellow Sea, and the maximum heat gain occurs in June. The maximum heat loss occurs in January over the study area, except the Yellow Sea where the heat loss is maximum in December. The annual mean value of the net heat flux in the East/Japan Sea is −108 W/m2 which is about twice the value of Hirose et al. (1996) or about 30% higher than Kato and Asai (1983). For the Yellow Sea, it is about −89 W/m2 and it becomes −75 W/m2 in the East China Sea. This increase in values of the net heat flux comes mostly from the turbulent fluxes which are strongly dependent on the wind speed, which fluctuates largely during the winter season.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-904X
    Keywords: nanocrystals ; submicron crystals ; suspensions ; steam sterilization ; physical stability ; surfactants ; cloud point ; ethyl diatrizoate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To study the effects of formulation variables on the physical stability of a submicron crystal (nanocrystal) suspension under steam sterilization conditions. Methods. Suspensions of ethyl diatrizoate nanocrystals were prepared by wet milling in the presence of the surfactant poloxamine 908. Particle size distribution and zeta potential were measured by photon correlation spectroscopy. Results. On heating, the mean particle size of the nanocrystal suspension remained essentially unchanged up to 110°C, the cloud point of the stabilizing surfactant, but increased significantly above that temperature. The increase in particle size was a result of particle aggregation rather than crystal growth. Adding a cloud point booster to the suspension significantly minimized the particle aggregation at high temperatures. The purity of poloxamine 908 and the tonicity agent and buffer salt used also affected the heat stability of the suspension, the latter agents apparently through altering the surfactant cloud point. Conclusions. The aggregation of the ethyl diatrizoate nanocrystalline suspension under steam sterilization conditions was a result of phase separation of the stabilizing surfactant at its cloud point. When formulated with a cloud point booster to prevent the phase-separation, the suspension maintained its physical stability under steam sterilization without any significant change in particle size distribution.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-904X
    Keywords: nonionic surfactants ; cloud point ; cloud point boosters ; poloxamers ; poloxamines ; liquid formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To determine the cloud point of a variety of nonionic surfactants and to search for means to raise the surfactant cloud point in liquid formulations. Methods. Cloud points of nonionic surfactants were determined visually in a water bath. Organic compounds, many of which have been used as pharmaceutical excipients, were tested initially for effect on the cloud point of poloxamine 908. Four effective cloud point boosters (CPBs) from different structural classes were further tested on additional surfactants. Results. A number of compounds can raise the cloud point of nonionic surfactants. These cloud point boosters are classified into two categories: nonionic and ionic. The nonionic CPBs include poly(ethylene glycols), propylene glycol, methanol, ethanol, isopropanol, and 2-hydroxypropyl-β-cyclodextrin. They are effective at molar concentrations. The ionic CPBs include anionic and cationic surfactants, charged phospholipids, long chain fatty acids, and bile salts. They are effective at millimolar concentrations. Conclusions. The cloud point of nonionic surfactants used in liquid formulations can be modulated through the proper choice of excipient.
    Type of Medium: Electronic Resource
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