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  • 1
    Digitale Medien
    Digitale Medien
    Laparoscopic evaluation and treatment of intestinal malrotation in infants (1996)
    Springer
    Surgical endoscopy and other interventional techniques 10 (1996), S. 936-937 
    Details
    ISSN: 1432-2218
    Schlagwort(e): Laparoscopy ; Malrotation ; Ladd's procedure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Infants with intestinal malrotation present with bilious emesis and the diagnosis is generally obtained by an upper gastrointestinal barium study. Malrotation is suspected if the ligament of Treitz is not positioned to the left of the vertebral body. Barium enema may also be used to detect malrotation by noting the abnormal position of the cecum from its usual placement in the right lower quadrant, but this study is not as reliable due to the mobility of the cecum. Some infants may not have classic radiographic findings for malrotation, yet the contrast studies are not entirely normal. We recently treated two infants with recurrent vomiting whose UGI studies suggested intestinal malrotation. Laparoscopic exploration confirmed the diagnosis of malrotation. Laparoscopic correction (Ladd's procedure) of malrotation was carried out in one infant. The second infant underwent a traditional Ladd's procedure. The technique of laparoscopic Ladd's procedure is described. Laparoscopy may be used for the diagnosis and treatment of infants with intestinal malrotation. It may be especially helpful to verify the diagnosis in patients who do not have classic radiographic findings. Whether laparoscopy should be used in patients with midgut volvulus is debatable. Laparoscopic derotation of the volvulus in a setting where the bowel is markedly distended may be difficult and dangerous.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00188488
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  • 2
    Digitale Medien
    Digitale Medien
    Laparoscopic-assisted abdominal aortic aneurysm repair (1995)
    Springer
    Surgical endoscopy and other interventional techniques 9 (1995), S. 905-907 
    Details
    ISSN: 1432-2218
    Schlagwort(e): Laparoscopy ; Laparoscopic-assisted abdominal aortic aneurysm repair ; Vascular
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Since the advent of laparoscopy, the sweeping changes seen in general surgery have not been paralleled in vascular surgery. There have been case reports of laparoscopic-assisted aortobifemoral bypass for occlusive disease. Because aneurysmal disease comprises the majority of aortic surgery, we pursued animal and cadaveric feasibility studies for laparoscopic-assisted abdominal aortic aneurysm (AAA) repair. We present a case report of the first clinical case performed under Institutional Review Board protocol using this technique. The patient was a 62-year-old male with a 6-cm infrarenal AAA. After obtaining a pneumoperitoneum, a modified fish retractor was used to exclude the bowel. Ten 11-mm ports provided access to laparoscopically dissect the neck of the aneurysm and the iliac vessels. Then, a 10-cm minilaparotomy was performed and standard vascular clamps were inserted via the port incisions. Standard aneurysmorraphy was performed with a polytetrafluoroethylene (PTFE) tube graft. Laparoscopy conferred three major benefits: better visualization of the aneurysm neck, less bowel manipulation, and avoidance of hypothermia. This case report illustrates the feasibility of laparoscopic-assisted aneurysm repair. Controlled human studies will define the role of laparoscopy in AAA surgery.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00768889
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  • 3
    Digitale Medien
    Digitale Medien
    Effect of some ternary additions on the sulfidation of Ni-Mo alloys (1990)
    Springer
    Oxidation of metals 33 (1990), S. 103-133 
    Details
    ISSN: 1573-4889
    Schlagwort(e): Ni-Mo alloys ; ternary additions ; sulfidation ; MoS2, intercalation ; Al0.55Mo2S4
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Five ternary additions, Cr, Ti, Mn, V, and Al were studied at equi-atomicpercent levels (17 a/o) for their effect on the sulfidation behavior of Ni-19a/o Mo (28–30 w/o) over the range of 600–800°C in 0.01 atm S2. Al was by far the most effective addition. A linear decrease in log kp vs. Al content was observed up to 7.5w/o Al, beyond which no further change was observed. All alloys followed the parabolic rate law. Arrhenius plots gave activation energies of 36.9–41.2 Kcal/mol for alloys containing Ti, Cr, Mn, and V, whereas the activation energies for Al-containing alloys were 47.2 Kcal/mol, indicating that a different diffusion process was involved. Complex scales were formed on all alloys, consisting of an outer layer of Nis1+x and complex inner layers which depended upon alloy composition. Two alloys, those with Cr and Mn, formed intermediate layers of Cr2S3 and MnS, respectively, but these layers had little effect on the kinetics. MoS2 was a constituent of the inner scales except for the alloys with Al. A ternary sulfide, Al0.55Mo2S4 and Al2S3 were observed. The presence of the mixed sulfide was always associated with the low sulfidation rates. The formation of MoS2 on alloys results in a different, less-protective behavior than for MoS2 formed on pure Mo. This effect is due to the intercalation of Ni into MoS2 in octahedral positions between the weakly bonded layers of covalently bonded sheets of trigonal prisms. The size of Al+3 is too small to be intercalated, and thus MoS2 is destabilized by Al.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00665672
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  • 4
    Digitale Medien
    Digitale Medien
    Sulfidation kinetics and mechanism of some Ni-Mo-Al and Ni-Al alloys over the temperature range 600–800°C (1990)
    Springer
    Oxidation of metals 33 (1990), S. 399-423 
    Details
    ISSN: 1573-4889
    Schlagwort(e): sulfidation ; Ni-Mo-Al alloys ; Ni-Al alloys ; Al0.55Mo2S4 ; Al2S3
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract The sulfidation behavior of five Ni-Mo-Al ternary alloys and two Ni-Al binary alloys was studied over the temperature range 600–800°C in sulfur vapor of 10−2 atm. The effect of sulfur pressure was also investigated at $$P_{S_2 } = 10^{ - 2} $$ and10−4 atm. using two Ni-Mo-Al alloys. The sulfidation of all Ni-Mo-Al andNi-Al alloys followed the parabolic rate law. The sulfidation rate decreasedwith increasing Al content for a given Mo content for Ni-Mo-Al alloys. Twobinary alloys, Ni-13.5Al and Ni-31Al, sulfidized at comparable rates toNi-30Mo-7.5Al, which has excellent sulfidation resistance. The activationenergies for ternary alloys range from 44.8–50.8 kcal/mol, whereas those forNi-13.5Al and Ni-31Al are 41.5 and 39.1 kcal/mol, respectively. Complexscales formed on all Ni-Mo-Al alloys, consisting of an outer layer of nickelsulfide and an inner layer of MoS2, A12S3, and Al0.55Mo2S4. Sulfide scalesformed on Ni-Al alloys were bilayered, consisting of an outer layer of nickelsulfide and an inner layer of A12S3. The low sulfidation rate of the ternaryalloys was attributed to the combined presence of both A12S3 and Al0.55Mo2S4.The sulfidation kinetics of two Ni-Mo-Al alloys are independent of sulfurpressure, suggesting that the growth of the inner layer was the dominant process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00666807
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  • 5
    Digitale Medien
    Digitale Medien
    High-temperature sulfidation behavior of Ni-Nb alloys (1989)
    Springer
    Oxidation of metals 31 (1989), S. 237-263 
    Details
    ISSN: 1573-4889
    Schlagwort(e): sulfidation ; nickel-niobium ; multilayered scale ; NbS2 ; NiNb3S6
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract The sulfidation properties of Ni-Nb alloys containing additions of niobium up to 40 wt.% have been studied at $$P_{S_2 } = 0.01$$ atm over the temperature range 550-700 °C. The sulfidation reactions followed the parabolic rate law; the sulfidation rates decreased with increasing amounts of niobium. An Arrhenius plot of the rate constants gave activation energies of 25.0+3.5 kcal/ mole. The scales formed on Ni-Nb alloys were multilayered, generally consisting of an outer layer of nickel sulfide ( NiS1+x and Ni3S2) and an inner complex layer of NiNb3S6 plus NbS2. The position of the original metal surface was notedy platinum-wire marker experiments to be the interface between the inner andouter layers. The location of the marker indicates that the outer layer, generally greater in thickness than the inner layer, grew by outward diffusion of the nickel cations, and the inner layer formed probably by the inward diffusion of sulfur. Neither preferential sulfidation nor internal sulfidation was observed. The development of the scale structures from the transient stage to steady state was also studied.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00846688
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  • 6
    Digitale Medien
    Digitale Medien
    The correlation between phase behavior and structure of a four-component system, poly-ethylene glycol/sodium dodecyl sulfate/pentanol/H2OThis paper was presented at the 5th International Conference on Surface and Colloid Science and the 59th Division of Colloid and Interface Science, American Chemical Society, held in Potsdam, New York, June, 1985. (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 32 (1986), S. 4383-4392 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The change in the concentration of sodium dodecyl sulfate (SDS) can, in fact, affect directly the correlation between phase behavior and structure of a four-component system, polyethylene glycol/sodium dodecyl sulfate/pentanol/H2O. Experimental results indicate that the phenomena of microemulsion and lamellar liquid crystals can take place at a concentration of SDS greater than 5% and 17% by weight, respectively. In our experiments, these liquid crystals are tested and found to be hydrophilic and their rheological properties to be non-Newtonian as well.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1986.070320408
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  • 7
    Digitale Medien
    Digitale Medien
    Raman spectral studies of nucleic acids. XI. Conformations of yeast tRNAPhe and E. coli ribosomal RNA in aqueous solution and in the solid statePaper X in this series is G. J. Thomas, Jr., M. C. Chen, and K. A. Hartman, Biochim. Biophys. Acta, 324, 37 (1973) (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 615-626 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Laser-excited Raman spectra of tRNAPhe from yeast and of fractionated 16S and 23S rRNA from E. coli are reported for samples in aqueous solution and in the solid state. The Raman scattering spectrum of each RNA is not significantly altered by the change from an aqueous to a solid environment and displays the same characteristic frequencies and intensities associated with ordered polyribonucleotide structures. Unlike DNA, the backbone conformation of RNA thus appears to be largely insensitive to gross changes in the degree of hydration.Raman scattering from the phosphate group vibrations of aqueous tRNAyeastPhe is qualitatively and quantitatively the same as obtained from previously studied tRNA's and is indicative of a highly ordered conformational structure in which some 85% of the nucleotide residues are in ordered configurations. The major differences observed between spectra of tRNA and rRNA are attributed to differences in base composition of these RNA's.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1974.360130313
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  • 8
    Digitale Medien
    Digitale Medien
    Copolyesters. I. Sequence distribution of poly(butylene terephthalate-co-adipate) copolyesters determined by 400 MHz NMR (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 40 (1990), S. 1053-1057 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1990.070400537
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  • 9
    Digitale Medien
    Digitale Medien
    Cure characteristics of unaccelerated sulfur vulcanization of epoxidized natural rubber (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1569-1574 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The curing characteristics of unaccelerated sulfur vulcanization of ENR 25 and ENR 50 were studied in the temperature range from 100-180°C. The range of sulfur loading was from 1.5 to 6.5 phr. The scorch time was determined by Mooney Shearing Disk Viscometer whereas the initial cure rate, maximum torque, and reversion properties were obtained from the Moving Die Rheometer (MDR 2000). Results shows that ENR 25 gives a longer scorch time than ENR 50, an observation similar to that in an accelerated system reported earlier. For temperature 〈 120°C, scorch time depends exponentially on sulfur loading for both rubbers. However, this dependence diminishes as temperature is increased. This observation is attributed to the availability of activated sulfur molecules for vulcanization. The initial cure rate and maximum torque increases with increasing sulfur loading. ENR 50, however, exhibits higher value than ENR 25, suggesting faster cure in the former. For a fixed sulfur loading, reversion is a time and temperature-dependent phenomenon. It decreases with increasing sulfur loading because of the increase of cross-linking density for both rubbers stuided. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Nylon 4/HEMA chemical homografted membrane (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 489-498 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: To enhance the degree of grafting, homografting copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto nylon 4 using a chemical initiator has been attempted. The factors that affect the grafting copolymerization are the concentration of reactants, reaction time, and temperature. The dialysis permeabilities of solutes, water content, surface energy, mechanical properties, and blood compatibility of the membrane were investigated. Under the same reaction conditions, the degree of grafting by the homografting method is remarkably higher than of the heterografting method for the nylon 4-HEMA grafting system. The dialysis permeabilities of NaCl, vitamin B12, and ovalbumin of the homografted membrane with a 14.8% degree of grafting are 2.760, 0.392, and 0.073 × 10-5 cm2/min, respectively. These permeabilities are higher than the corresponding ones of ungrafted nylon 4 membrane. The mol ratios of adsorbed fibrinogen/albumin (F/A) of the heterografted membranes were found to decrease from 0.53 to 0.33, and the surface energy, to increase from 40.6 to 46.4 dyn/cm with the degree of grafting in the range of 12.5-29.9%, and their relationship is not remarkable for the homografted membranes for which the mol ratios of F/A are about 0.22-0.32 with the degree of grafting in the range of 14.8-103.8%. Observed from scanning electron micrographs of the membrane surface, denseness was found to be important to improve blood compatibility. Based on the dialysis permeabilities of solutes and the blood compatibility observed in this study, the homografted nylon 4/HEMA membrane can be considered as a hemodialysis material.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1992.070460315
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