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Search Results: 1 - 10 of 431 matches for " Kummer KM "
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Decreased cervical cancer cell adhesion on nanotubular titanium for the treatment of cervical cancer
Crear J, Kummer KM, Webster TJ
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S38500
Abstract: reased cervical cancer cell adhesion on nanotubular titanium for the treatment of cervical cancer Original Research (516) Total Article Views Authors: Crear J, Kummer KM, Webster TJ Published Date March 2013 Volume 2013:8 Pages 995 - 1001 DOI: http://dx.doi.org/10.2147/IJN.S38500 Received: 25 September 2012 Accepted: 06 November 2012 Published: 07 March 2013 Jara Crear, Kim M Kummer, Thomas J Webster School of Engineering, Brown University, Providence, RI, USA Abstract: Cervical cancer can be treated by surgical resection, chemotherapy, and/or radiation. Titanium biomaterials have been suggested as a tool to help in the local delivery of chemotherapeutic agents and/or radiation to cervical cancer sites. However, current titanium medical devices used for treating cervical cancer do not by themselves possess any anticancer properties; such devices act as carriers for pharmaceutical agents or radiation sources and may even allow for the growth of cancer cells. Based on studies, which have demonstrated decreased lung, breast, and bone cancer cell functions on nanostructured compared to nanosmooth polymers, the objective of the present in vitro study was to modify titanium to possess nanotubular surface features and determine cervical cancer cell adhesion after 4 hours. Here, titanium was anodized to possess nanotubular surface features. Results demonstrated the ability to decrease cervical cancer cell adhesion by about a half on nanotubular compared to currently used nanosmooth titanium (without the use of chemotherapeutics or radiation), opening up numerous possibilities for the use of nanotubular titanium in local drug delivery or radiation treatment of cervical cancer.
Decreased cervical cancer cell adhesion on nanotubular titanium for the treatment of cervical cancer
Crear J,Kummer KM,Webster TJ
International Journal of Nanomedicine , 2013,
Abstract: Jara Crear, Kim M Kummer, Thomas J Webster School of Engineering, Brown University, Providence, RI, USA Abstract: Cervical cancer can be treated by surgical resection, chemotherapy, and/or radiation. Titanium biomaterials have been suggested as a tool to help in the local delivery of chemotherapeutic agents and/or radiation to cervical cancer sites. However, current titanium medical devices used for treating cervical cancer do not by themselves possess any anticancer properties; such devices act as carriers for pharmaceutical agents or radiation sources and may even allow for the growth of cancer cells. Based on studies, which have demonstrated decreased lung, breast, and bone cancer cell functions on nanostructured compared to nanosmooth polymers, the objective of the present in vitro study was to modify titanium to possess nanotubular surface features and determine cervical cancer cell adhesion after 4 hours. Here, titanium was anodized to possess nanotubular surface features. Results demonstrated the ability to decrease cervical cancer cell adhesion by about a half on nanotubular compared to currently used nanosmooth titanium (without the use of chemotherapeutics or radiation), opening up numerous possibilities for the use of nanotubular titanium in local drug delivery or radiation treatment of cervical cancer. Keywords: cervical cancer, titanium, nanotubular, cell density
Fructose-enhanced reduction of bacterial growth on nanorough surfaces
Durmus NG, Taylor EN, Inci F, Kummer KM, Tarquinio KM, Webster TJ
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S27957
Abstract: uctose-enhanced reduction of bacterial growth on nanorough surfaces Original Research (3034) Total Article Views Authors: Durmus NG, Taylor EN, Inci F, Kummer KM, Tarquinio KM, Webster TJ Published Date February 2012 Volume 2012:7 Pages 537 - 545 DOI: http://dx.doi.org/10.2147/IJN.S27957 Received: 05 November 2011 Accepted: 23 November 2011 Published: 01 February 2012 Naside Gozde Durmus1, Erik N Taylor1, Fatih Inci3,4, Kim M Kummer1, Keiko M Tarquinio5, Thomas J Webster1,2 1School of Engineering, Brown University, Providence, RI, USA; 2Department of Orthopedics, Brown University, Providence, RI, USA; 3Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard-MIT Health Sciences and Technology, Harvard Medical School, MA, USA; 4Istanbul Technical University, Molecular Biology-Genetics and Biotechnology Program, Mobgam, Maslak, Istanbul, Turkey; 5Division of Pediatric Critical Care Medicine, Rhode Island Hospital, Providence, RI, USA Abstract: Patients on mechanical ventilators for extended periods of time often face the risk of developing ventilator-associated pneumonia. During the ventilation process, patients incapable of breathing are intubated with polyvinyl chloride (PVC) endotracheal tubes (ETTs). PVC ETTs provide surfaces where bacteria can attach and proliferate from the contaminated oropharyngeal space to the sterile bronchoalveolar area. To overcome this problem, ETTs can be coated with antimicrobial agents. However, such coatings may easily delaminate during use. Recently, it has been shown that changes in material topography at the nanometer level can provide antibacterial properties. In addition, some metabolites, such as fructose, have been found to increase the efficiency of antibiotics used to treat Staphylococcus aureus (S. aureus) infections. In this study, we combined the antibacterial effect of nanorough ETT topographies with sugar metabolites to decrease bacterial growth and biofilm formation on ETTs. We present for the first time that the presence of fructose on the nanorough surfaces decreases the number of planktonic S. aureus bacteria in the solution and biofilm formation on the surface after 24 hours. We thus envision that this method has the potential to impact the future of surface engineering of biomaterials leading to more successful clinical outcomes in terms of longer ETT lifetimes, minimized infections, and decreased antibiotic usage; all of which can decrease the presence of antibiotic resistant bacteria in the clinical setting.
Progress and problems in quantum gravity
Wolfgang Kummer
Physics , 2005,
Abstract: From the point of view of an uncompromising field theorist quantum gravity is beset with serious technical and, above all, conceptual problems with regard especially to the meaning of genuine "physical" observables. This situation is not really improved by the appearance of recent attempts to reformulate gravity within some novel framework.However, the original aim, a background-independent quantum theory of gravity, can be achieved in a particular area, namely 2d dilaton quantum gravity without any assumptions beyond standard quantum field theory. Some important by-products of the research of the "Vienna School" include the introduction of the concept of Poisson-Sigma models, a verification of the "virtual Black Hole" and the extensions to N = (1,1) and N = (2,2) 2d-supergravity, for which complete solutions of some old problems have been possible which are relevant for superstring theory
General Treatment of All 2d Covariant Models
W. Kummer
Physics , 1996,
Abstract: General matterless models of gravity include dilaton gravity, arbitrary powers in curvature, but also dynamical torsion. They are a special class of "Poisson-sigma-models" whose solutions are known completely, together with their general global structure. Beside the ordinary black hole, arbitrary singularity structures can be studied. It is also possible to derive an action "backwards", starting from a given manifold. The role of conservation laws, Noether charge and the quantization have been investigated. Scalar and fermionic matter fields may be included as well.
2d quantum gravity with torsion, dilaton theory and black hole formation
Wolfgang Kummer
Physics , 2000,
Abstract: Starting from the work of the author in 1990 with different collaborators, essential progress in 2d gravity theories has been made. Now all such theories (and not only certain special models) can be treated at the classical as well as at the quantum level. New physical insights have been obtained, as e.g. the ``virtual black hole''. The formalism developed in this context recently also finds increasing interest in mathematical physics.
On the Gauge-Independence of the S-Matrix
W. Kummer
Physics , 2001, DOI: 10.1007/s100520100709
Abstract: The S-matrix is invariant with respect to the variation of any (global) parameter involved in the gauge fixing conditions, if that variation is accompanied by a certain redefinition of the basis of polarization vectors. Renormalizability of the underlying gauge theory is not required. The proof is nonperturbative and, using the `extended' BRS transformation, quite simple.
A Note on the Hyperbolicity Cone of the Specialized Vámos Polynomial
Mario Kummer
Mathematics , 2013,
Abstract: The specialized V\'amos polynomial is a hyperbolic polynomial of degree four in four variables with the property that none of its powers admits a definite determinantal representation. We will use a heuristical method to prove that its hyperbolicity cone is a spectrahedron.
Eigenvalues of symmetric matrices over integral domains
Mario Kummer
Mathematics , 2015,
Abstract: We consider the class of all integral domains A with the property that every integral and totally real element over A is an eigenvalue of a symmetric matrix over A. We show that this class contains all regular domains and all integrally closed domains with formally real field of fractions. In the case where A is the ring of integers of an algebraic number field we show that the size of matrices grows linearly in the degree of the totally real element. These results settle two questions raised by Bass, Estes and Guralnick.
Determinantal Representations and Bézoutians
Mario Kummer
Mathematics , 2013,
Abstract: We show that for every smooth hyperbolic polynomial h there is another hyperbolic polynomial q such that qh has a definite determinantal representation. This is proved by considering sum-of-squares decompositions of certain bilinear forms called B\'ezoutians. Besides commutative algebra, the proof relies on results from real algebraic geometry.
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