246 research outputs found
Analytical, Optimal, and Sparse Optimal Control of Traveling Wave Solutions to Reaction-Diffusion Systems
This work deals with the position control of selected patterns in
reaction-diffusion systems. Exemplarily, the Schl\"{o}gl and FitzHugh-Nagumo
model are discussed using three different approaches. First, an analytical
solution is proposed. Second, the standard optimal control procedure is
applied. The third approach extends standard optimal control to so-called
sparse optimal control that results in very localized control signals and
allows the analysis of second order optimality conditions.Comment: 22 pages, 3 figures, 2 table
Good physicians from the perspective of their patients
BACKGROUND: It is not currently known what is the patient's viewpoint of a "good" physician. We set out to define patient's priorities regarding different physician's attributes in 3 domains important in medical care. METHODS: Patients hospitalized or attending clinics at a large teaching hospital selected the 4 attributes that they considered most important out of 21 listed arbitrarily in a questionnaire. The questionnaire included 7 items each in the domains of patient autonomy, professional expertise and humanism. RESULTS: Participating patients (n = 445, mean age 57.5 ± 16 years) selected professional expertise (50%), physician's patience and attentiveness (38% and 30%, respectively), and informing the patient, representing the patient's interests, being truthful and respecting patient's preferences (25–36% each) as the most essential attributes. Patient's selections were not significantly influenced by different demographic or clinical background. Selections of attributes in the domain of patient's autonomy were significantly more frequent and this was the preferred domain for 31% and as important as another domain for 16% – significantly more than the domain of professional expertise (P = 0.008), and much more than the domain of humanism and support (P < 0.0005). CONCLUSIONS: Patients studied want their physicians to be highly professional and expert clinicians and show humaneness and support, but their first priority is for the physician to respect their autonomy
The feasibility of gene therapy in the treatment of head and neck cancer
Standard approach to the treatment of head and neck cancer include surgery, chemotherapy, and radiation. More recently, dramatic increases in our knowledge of the molecular and genetic basis of cancer combined with advances in technology have resulted in novel molecular therapies for this disease. In particular, gene therapy, which involves the transfer of genetic material to cells to produce a therapeutic effect, has become a promising approach. Clinical trials concerning gene therapy strategies in head and neck cancer as well as combination of these strategies with chemotherapy and radiation therapy will be discussed
Joint multi-field T1 quantification for fast field-cycling MRI
Acknowledgment This article is based upon work from COST Action CA15209, supported by COST (European Cooperation in Science and Technology). Oliver Maier is a Recipient of a DOC Fellowship (24966) of the Austrian Academy of Sciences at the Institute of Medical Engineering at TU Graz. The authors would like to acknowledge the NVIDIA Corporation Hardware grant support.Peer reviewedPublisher PD
Accessory parameters for Liouville theory on the torus
We give an implicit equation for the accessory parameter on the torus which
is the necessary and sufficient condition to obtain the monodromy of the
conformal factor. It is shown that the perturbative series for the accessory
parameter in the coupling constant converges in a finite disk and give a
rigorous lower bound for the radius of convergence. We work out explicitly the
perturbative result to second order in the coupling for the accessory parameter
and to third order for the one-point function. Modular invariance is discussed
and exploited. At the non perturbative level it is shown that the accessory
parameter is a continuous function of the coupling in the whole physical region
and that it is analytic except at most a finite number of points. We also prove
that the accessory parameter as a function of the modulus of the torus is
continuous and real-analytic except at most for a zero measure set. Three
soluble cases in which the solution can be expressed in terms of hypergeometric
functions are explicitly treated.Comment: 30 pages, LaTex; typos corrected, discussion of eq.(74) improve
Cancer chemoprevention: lessons learned and future directions
The concept of delaying or preventing epithelial transformation remains a viable and attainable goal for the future. Drug-based strategies for chemoprevention of the future may predominantly rely upon targeted therapies with tolerable but defined toxicities for treatment of individuals diagnosed with intraepithelial neoplasias. Foods, diet manipulation strategies, or nutraceuticals may be more appropriate to delay or prevent carcinogenesis progression in healthy populations with genetic or epidemiologic evidence of risk for future transformation
Sobolev spaces on non-Lipschitz subsets of Rn with application to boundary integral equations on fractal screens
We study properties of the classical fractional Sobolev spaces on non-Lipschitz subsets of Rn. We investigate the extent to which the properties of these spaces, and the relations between them, that hold in the well-studied case of a Lipschitz open set, generalise to non-Lipschitz cases. Our motivation is to develop the functional analytic framework in which to formulate and analyse integral equations on non-Lipschitz sets. In particular we consider an application to boundary integral equations for wave scattering by planar screens that are non-Lipschitz, including cases where the screen is fractal or has fractal boundary
Senescent cells evade immune clearance via HLA-E-mediated NK and CD8(+) T cell inhibition
Senescent cells accumulate in human tissues during ageing and contribute to age-related
pathologies. The mechanisms responsible for their accumulation are unclear. Here we show
that senescent dermal fibroblasts express the non-classical MHC molecule HLA-E, which
interacts with the inhibitory receptor NKG2A expressed by NK and highly differentiated CD8
+ T cells to inhibit immune responses against senescent cells. HLA-E expression is induced
by senescence-associated secretary phenotype-related pro-inflammatory cytokines, and is
regulated by p38 MAP kinase signalling in vitro. Consistently, HLA-E expression is increased
on senescent cells in human skin sections from old individuals, when compared with those
from young, and in human melanocytic nevi relative to normal skin. Lastly, blocking the
interaction between HLA-E and NKG2A boosts immune responses against senescent cells
in vitro. We thus propose that increased HLA-E expression contributes to persistence of
senescent cells in tissues, thereby suggesting a new strategy for eliminating senescent cells
during ageing
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