Search Results - (Author, Cooperation:G. Georgiou)

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  1. 1
    Staff View
    Publication Date:
    2014-03-05
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    AIDS Vaccines/chemistry/immunology ; Amino Acid Sequence ; Antibodies, Neutralizing/chemistry/genetics/*immunology/isolation & purification ; Antibody Affinity/genetics/immunology ; Antigens, CD4/immunology/metabolism ; B-Lymphocytes/cytology/immunology/metabolism ; Binding Sites/immunology ; Cell Lineage ; Complementarity Determining Regions/chemistry/genetics/immunology ; Epitope Mapping ; Epitopes, B-Lymphocyte/chemistry/immunology ; Evolution, Molecular ; HIV Antibodies/chemistry/genetics/*immunology/isolation & purification ; HIV Envelope Protein gp160/*chemistry/*immunology ; HIV Infections/immunology ; HIV-1/chemistry/immunology ; Humans ; Models, Molecular ; Molecular Sequence Data ; Neutralization Tests ; Protein Structure, Tertiary ; Somatic Hypermutation, Immunoglobulin/genetics
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Staff View
    Publication Date:
    2018-06-05
    Publisher:
    The American Association of Immunologists (AAI)
    Print ISSN:
    0022-1767
    Electronic ISSN:
    1550-6606
    Topics:
    Medicine
    Published by:
    http://www.aai.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Lindenberger, S. ; Georgiou, G. E. ; Hillenius, S. J. ; Luftman, H. ; Baiocchi, F. A. ; Sheng, T. T. ; Field, R. L.

    [S.l.] : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The microstructure and metal-silicon work function was evaluated for polycrystalline Si (poly-Si) films (∼3500 A(ring)) implanted with BF2, with and without a CoSi2 superlayer. The poly-Si implant doses were 2, 4, and 6×1015 cm−2, activated at 800–950 °C, for various times. The work function is observed to be dependent upon the BF2 dose, the anneal time, the anneal temperature, and independent of the presence of a thin CoSi2 superlayer subsequently sintered on the poly-Si. The work function is not affected by additional implants into a CoSi2 superlayer. The measured work function for this material is shifted to more positive values by penetration of boron from the gate, into the oxide and possibly into the substrate during a (approximately-greater-than)900 °C activation cycle. The major correlation of CoSi2/poly-Si interface roughness is with poly-Si grain size. The interface becomes smoother as the poly-Si grain size becomes smaller. Similarly, the maximum extent of CoSi2 asperities is less for Co sintered on BF2 implanted poly-Si when the poly-Si is activated at 900 °C (smaller grain size) rather than at 950 °C. Within statistical limitations of cross-section transmission electron microscopy and sensitivity limitations of Rutherford backscatterings, CoSi2 asperities do not extend close enough to the (4000-A(ring)-thick) poly-Si/SiO2 interface to affect complimentary metal-oxide-semiconductor device characteristics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.347241

    Articles: DFG German National Licenses
  4. 4
    Georgiou, G. E. ; Sheng, T. T. ; Baiocchi, F. A. ; Kovalchick, J. ; Lynch, W. T. ; Malm, D.

    [S.l.] : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We describe reverse bias diode leakage and physical analysis (secondary ion mass spectroscopy, Rutherford backscattering and transmission electron microscopy) data from shallow n+/p junctions made by implanting various doses of arsenic into polycrystalline Si and out diffusing at various temperature/time conditions, into the underlying (100) Si substrate. The polycrystalline Si is cobalt disilicided to provide the first level of metallization. The minimum process specifications giving good junction quality (reverse bias diode leakage current density ≤10 nA/cm2 at 10 V) are 7×1015 cm−2 As out diffused at 950 °C, 30 min with a junction depth 1200 A(ring) below the polycrystalline Si. At these conditions, most of the As ((approximately-greater-than)90%) uniformly redistributes in the polycrystalline Si. There is a segregation to the polycrystalline Si/Si interface which is characterized by a porous, 〈50 A(ring) thin silicon oxide interface. The polycrystalline Si/Si interface is also characterized by a laterally non-uniform large grain(∼2000 A(ring)) or epitaxial regrowth at the 950 °C process temperature. These interface conditions may be used to explain the ∼20% high leakage population which is independent of out-diffusion condition at high As dose. Such a high sport population is not observed when P is implanted into polycrystalline Si and out diffused at 900 °C, 30 min to obtain ∼2500-A(ring)-deep junctions below the polycrystalline Si/Si interface.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.346309

    Articles: DFG German National Licenses
  5. 5
    Georgiou, G. E. ; Sheng, T. T. ; Kovalchick, J. ; Lynch, W. T. ; Malm, D.

    [S.l.] : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We describe reverse bias diode leakage and physical analysis (secondary ion mass spectroscopy, Rutherford backscattering and transmission electron microscopy) data from shallow p+/n junctions made by implanting various doses of BF2 into polycrystalline Si and out-diffusing at various temperature/time conditions, into the underlying (100) Si substrate. The polycrystalline Si is cobalt disilicided to provide the first level of metallization. Subsequent metallization consists of electroless plated Co followed by sputtered Al. The minimum process specifications giving good junction quality (reverse bias diode leakage current density ≤10 nA/cm2 at 10 V) are 5×1015 cm−2 BF2 outdiffused at 900 °C, 30 min with a junction depth 1200 A(ring) below the polycrystalline Si. At these conditions, most of the BF2 (〉90%) uniformly redistributes in the polycrystalline Si. There is a slight increase in B concentration towards the polycrystalline Si/Si interface which is characterized by a porous, 〈50-A(ring) thin silicon oxide interface. The polycrystalline Si/Si interface is also characterized by a peaked fluorine concentration. The lower boron dose diffusing into the Si substrate may be used to explain the observation that these p+/n diodes are ∼10 times leakier than similar n+/p diodes made by outdiffusing As or P implanted from the polycrystalline Si diffusion source.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.346335

    Articles: DFG German National Licenses
  6. 6
    Eshraghi, S. A. ; Georgiou, G. E. ; Liu, R.

    [S.l.] : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The effect of blanket chemical vapor deposition (CVD) of tungsten (SiH4 reduction) on shallow CoSi2 junctions using 450–1800 A(ring) of titanium-tungsten (TiW) as a diffusion barrier has been investigated. Thermal stability of W/TiW and Al/W/TiW is studied by measuring the reverse leakage current at 25 °C anneal intervals. The Al/TiW structure has been used as a reference. W/TiW junctions with ≤700 A(ring) of TiW are less stable than Al/TiW junctions. The addition of Al on top of CVD W enhances the junction degradation considerably. p+n junctions are more sensitive to the barrier failure. The effect of CVD W deposition temperature has been studied. Junctions exposed to 480 °C CVD W deposition temperature showed a lower leakage than those at 300 °C.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.346465

    Articles: DFG German National Licenses
  7. 7
    Eagles, P. M. ; Georgiou, G. A.

    [S.l.] : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1089-7666
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The stability of Jeffery–Hamel flow in a divergent wedge is considered by means of some initially localized disturbances, whose evolution downstream with time is studied by an integral of fixed frequency modes with respect to the frequency parameter. It is found, typically, that even in regions of parameter space that are nominally "unstable,'' the original localized disturbance grows very little before decaying downstream.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.866423

    Articles: DFG German National Licenses
  8. 8
    Tamiolakis, D. ; Venizelos, I. ; Nikolaidou, S. ; Kostopoulou, A. ; Georgiou, G. ; Boglou, P. ; Papadopoulos, N.

    Oxford, UK : Blackwell Science Ltd
    Published 2004
    Staff View
    ISSN:
    1365-2303
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1365-2303.2004.00115.x

    Articles: DFG German National Licenses
  9. 9
    Staff View
    ISSN:
    0167-7799
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0167-7799(93)90068-K

    Articles: DFG German National Licenses
  10. 10
    Staff View
    ISSN:
    1437-9813
    Keywords:
    Urethral rupture ; Urethral strictures ; Incontinence ; Impotence ; Pelvic trauma
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract Our experience with the management of ten children with posterior urethral rupture in the early phase is presented. In seven children (six boys and one girl) in whom a complete rupture had occurred, a suprapubic approach was used and a Foley catheter was passed as a splint after end-to-end primary anastomisis of the torn urethra. In three cases rupture was partial; one was iatrogenic and the others were traumatic. The former was managed by a perineal incision with urethral reconstruction and a cystostomy for urinary diversion. In one traumatic partial tear, simple catheterization through the external meatus was sufficient for perfect healing, while in the second after unsuccessful catheterization, a cystostomy for 2 weeks led to a satisfactory outcome. Three of the seven children with complete rupture developed strictures, which required one or more sounds; one of them also underwent two internal (visual) urethrotomies. All currently have stable stricture formation. One other boy with strictures, who is now 16 years of age, periodically needs bougienage and is completely impotent with probably diminished libido. Nine children now have normal micturition and in six boys erections have been established. Two have begun to ejaculate, but the rest are still too young for definite conclusions. We believe that for a completely disrupted urethra primary end-to-end anastomosis with a few approximating sutures over a Foley catheter placed as a splint is feasible in children and should be attempted as the procedure of choice.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00169667

    Articles: DFG German National Licenses
  11. 11
    Staff View
    ISSN:
    1437-9813
    Keywords:
    Liver trauma ; splenic trauma ; Abdominal CT ; Liver and spleen scanning
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract Thirty-nine children with blunt liver and/or splenic injury were treated in our department from 1979 to 1987; 23 had a splenic injury, 10 a hepatic injury, and the remaining 6 had both. The diagnosis was suggested by the history and physical examination and was confirmed by CT and radioisotope scanning. Every hemodynamically stable patient was initially managed non-operatively. The children who failed to respond to conservative treatment and had unstable vital signs indicating intractable hemorrhage were eventually operated upon. Every effort was made to preserve the liver and spleen during the operation. Liver repair, splenorraphy alone or in combination with splenic artery ligation, and autotransplantation of splenic tissue were widely used procedures. Sixteen patients were successfully managed nonoperatively, but the remaining 23 required surgery. Only 5 children became completely asplenic and no liver lobe resection was performed. It is suggested that conservative management of children with liver and/or splenic injury is both safe and effective. When surgical intervention is inevitable great effort should be made to preserve liver and spleen.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00174344

    Articles: DFG German National Licenses
  12. 12
    Lin, S. -C. ; Carswell, K. S. ; Sharma, M. M. ; Georgiou, G.
    Springer
    Published 1994
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Abstract Bacillus licheniformis JF-2 synthesizes a surfactin-like lipopeptide that is the most effective biosurfactant known. In shake-flask cultures the biosurfactant is produced by actively growing cells (mid-linear phase), but subsequently it becomes rapidly internalized by the cells as soon as the culture enters the stationary phase. This deactivation phenomenon is a major hurdle in the efficient production of the biosurfactant. We have shown that the synthesis of the JF-2 lipopeptide is strongly dependent on O2 concentration with substantial production observed only in cultures grown under O2-limiting conditions. In continuous cultures the biosurfactant was produced only within a narrow window of low dilution rates. At a dilution rate of 0.12 h−1 and low dissolved O2, the biosurfactant concentration was maintained at 33 mg/l, which is virtually the same as the maximum concentration obtained in optimized batch fermentations.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00221219

    Articles: DFG German National Licenses
  13. 13
    Lin, S.-C. ; Sharma, M. M. ; Carswell, K. S. ; Georgiou, G.
    Springer
    Published 1994
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Abstract  Bacillus licheniformis JF-2 synthesizes a surf- actin-like lipopeptide that is the most effective biosurfactant known. In shake-flask cultures the biosurfactant is produced by actively growing cells (mid-linear phase), but subsequently it becomes rapidly internalized by the cells as soon as the culture enters the stationary phase. This deactivation phenomenon is a major hurdle in the efficient production of the biosurfactant. We have shown that the synthesis of the JF-2 lipopeptide is strongly dependent on O2 concentration with substantial production observed only in cultures grown under O2-limiting conditions. In continuous cultures the biosurfactant was produced only within a narrow window of low dilution rates. At a dilution rate of 0.12 h-1 and low dissolved O2, the biosurfactant concentration was maintained at 33 mg/l, which is virtually the same as the maximum concentration obtained in optimized batch fermentations.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s002530050144

    Articles: DFG German National Licenses
  14. 14
    Stathopoulos, C. ; Georgiou, G. ; Earhart, C. F.
    Springer
    Published 1996
    Staff View
    ISSN:
    1432-0614
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Abstract  The Lpp′OmpA(46–159) hybrid protein can serve as an efficient targeting vehicle for localizing a variety of procaryotic and eucaryotic soluble proteins onto the E. coli surface, thus providing a system for several possible biotechnology applications. Here we show that fusions between Lpp′OmpA(46–159) and bacterial alkaline phosphatase (PhoA), a normally periplasmic dimeric enzyme, are also targeted to the outer membrane. However, protease accessibility experiments and immunoelectron microscopy revealed that, unlike other periplasmic proteins, the PhoA domain of these fusions is not exposed on the cell surface in cells having an intact outer membrane. Conditions that affect the formation of disulfide bonds and the folding of the PhoA domain in the periplasm not only did not facilitate targeting to the cell surface but led to lethality when the fusion was expressed from a high-copy-number plasmid. Furthermore, E. coli expressing the Lpp′OmpA(46–159)-PhoA fusion exhibited strain- and temperature-dependent alterations in outer-membrane permeability. Our results are consistent with previous studies with other vehicles indicating that PhoA is not displayed on the surface when fused to cell-surface expression vectors. Presumably, the enzyme rapidly assumes a tightly folded dimeric conformation that cannot be transported across the outer membrane. The large size and quaternary structure of PhoA may define a limitation of the Lpp′OmpA(46– 159) fusion system for the display of periplasmic proteins on the cell surface. Alkaline phosphatase is a unique protein among a group of five periplasmic proteins (β-lactamase, alkaline phosphatase, Cex cellulase, Cex cellulose-binding domain, and a single-chain Fv antibody fragment), which have been tested as passengers for the Lpp′OmpA(46–159) expression system to date, since it was the only protein not displayed on the surface.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s002530050657

    Articles: DFG German National Licenses
  15. 15
    Staff View
    ISSN:
    0992-7689
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Geosciences
    Physics
    Notes:
    Abstract A statistical technique for image processing, the maximum cross correlation (MCC) method, was utilized on sequences of NOAA-AVHRR thermal data in order to explore the surface advective current dynamics at the discharge region of the Hellespont in the North Aegean Sea. A 2D numerical flow model was also used in order to simulate the barotropic flow pattern of the surface water layer. The model was forced with diurnal wind fields obtained for the same period as the satellite infrared images. The currents (magnitude and direction) derived from the two methods compare satisfactorily despite the fact that some model simplifications were made.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s00585-996-1221-1

    Articles: DFG German National Licenses
  16. 16
    Poullikkas, A. ; Karageorghis, A. ; Georgiou, G.
    Springer
    Published 1998
    Staff View
    ISSN:
    1432-0924
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes:
    Abstract In this work, the use of the Method of Fundamental Solutions (MFS) for solving elliptic partial differential equations is investigated, and the performance of various least squares routines used for the solution of the resulting minimization problem is studied. Two modified versions of the MFS for harmonic and biharmonic problems with boundary singularities, which are based on the direct subtraction of the leading terms of the singular local solution from the original mathematical problem, are also examined. Both modified methods give more accurate results than the standard MFS and also yield the values of the leading singular coefficients. Moreover, one of them predicts the form of the leading singular term.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s004660050320

    Articles: DFG German National Licenses
  17. 17
    Poullikkas, A. ; Karageorghis, A. ; Georgiou, G.
    Springer
    Published 1998
    Staff View
    ISSN:
    1432-0924
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes:
    Abstract We investigate the use of the Method of Fundamental Solutions (MFS) for solving inhomogeneous harmonic and biharmonic problems. These are transformed to homogeneous problems by subtracting a particular solution of the governing equation. This particular solution is taken to be a Newton potential and the resulting homogeneous problem is solved using the MFS. The numerical calculations indicate that accurate results can be obtained with relatively few degrees of freedom. Two methods for the special case where the inhomogeneous term is harmonic are also examined.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s004660050344

    Articles: DFG German National Licenses
  18. 18
    Fyrillas, Marios M. ; Georgiou, G. C.
    Springer
    Published 1998
    Staff View
    ISSN:
    1435-1528
    Keywords:
    Key words Shear flow ; Oldroyd-B model ; slip ; linear stability analysis ; asymptotic analysis
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Physics
    Notes:
    Abstract We consider the time-dependent shear flow of an Oldroyd-B fluid with slip along the fixed wall. Slip is allowed by means of a generic slip equation predicting that the shear stress is a non-monotonic function of the velocity at the wall. The complete one-dimensional stability analysis to one-dimensional disturbances is carried out and the corresponding neutral stability diagrams are constructed. Asymptotic results for large values of the elasticity number and finite element calculations are also presented. The instability regimes are within or coincide with the negative-slope regime of the slip equation. The numerical calculations agree with the linear stability results when the size of the initial perturbation is small. Large perturbations may destabilize a linearly stable steady state, leading to a periodic solution. The period and the amplitude of the periodic solutions increase with elasticity.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s003970050091

    Articles: DFG German National Licenses
  19. 19
    Georgiou, G. ; Shuler, M. L.

    New York, NY [u.a.] : Wiley-Blackwell
    Published 1986
    Staff View
    ISSN:
    0006-3592
    Keywords:
    Chemistry ; Biochemistry and Biotechnology
    Source:
    Wiley InterScience Backfile Collection 1832-2000
    Topics:
    Biology
    Process Engineering, Biotechnology, Nutrition Technology
    Notes:
    Mold growth and differentiation are closely related to the formation of secondary products. In solid-substrate fermentations this interrelationship is often more completely realized than in submerged cultures. Solid substrate reactions are used commercially in a limited manner in the western world, but are relatively common in Asia. Basic studies in solid-substrate fermentation should yield results applicable to all types of commercial mold fermentations for the production of a secondary product. This paper presents a relatively simple model for the growth of a mold colony on a solid surface with a defined medium utilizing glucose. Unlike submerged cultures the model must account for both cellular differentiation and the spatial heterogeneity in the system. Model parameters were estimated independently using literature values. The results of the simulation studies suggest that mass transfer limitations are at least partially responsible for the proliferation of differentiated structures on solid substrates as compared to liquid cultures. Since the concentration profile depends on the depth of the substratum, conditions that enhance conidia production can be achieved by controlling the depth of the solid medium.
    Additional Material:
    9 Ill.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1002/bit.260280314

    Articles: DFG German National Licenses
  20. 20
    Georgiou, G. C. ; Papanastasiou, T. C. ; Wilkes, J. O.

    Hoboken, NJ : Wiley-Blackwell
    Published 1988
    Staff View
    ISSN:
    0001-1541
    Keywords:
    Chemistry ; Chemical Engineering
    Source:
    Wiley InterScience Backfile Collection 1832-2000
    Topics:
    Chemistry and Pharmacology
    Process Engineering, Biotechnology, Nutrition Technology
    Additional Material:
    5 Ill.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1002/aic.690340918

    Articles: DFG German National Licenses