On the energy deposited by a quark moving in an N=4 SYM plasma

We evaluate the energy momentum tensor of a massive quark as it moves through an N=4 SYM quark gluon plasma at constant velocity. We find that in the near-quark region, where the dynamics is expected to be dominated by dissipative behavior, the energy density may be quantitatively characterized by a transient at velocities above the speed of sound of the plasma.Comment: 19 pages, 1 figure; Typos corrected, references adde

Zinc Gluconate in the Treatment of Dysgeusia—a Randomized Clinical Trial

In the treatment of dysgeusia, the use of zinc has been frequently tried, with equivocal results. The aim of the present randomized clinical trial, which involved a sufficiently large sample, was therefore to determine the efficacy of zinc treatment. Fifty patients with idiopathic dysgeusia were carefully selected. Zinc gluconate (140 mg/day; n = 26) or placebo (lactose; n = 24) was randomly assigned to the patients. The patients on zinc improved in terms of gustatory function (p < 0.001) and rated the dysgeusia as being less severe (p < 0.05). Similarly, signs of depression in the zinc group were less severe (Beck Depression Inventory, p < 0.05; mood scale, p < 0.05). With the exception of the salivary calcium level, which was higher in the zinc patients (p < 0.05), no other significant group differences were found. In conclusion, zinc appears to improve general gustatory function and, consequently, general mood scores in dysgeusia patients

Molekulare Veränderungen beim Pankreaskarzinom

Zusammenfassung: Grundlagen: Das Pankreaskarzinom hat eine infauste Prognose. Die Ursachen für das aggressive Tumorwachstum und die frühe Metastasierung sind nur unzureichend bekannt. Mit Hilfe von modernen molekularbiologischen Untersuchungstechniken ist es in den vergangenen Jahren gelungen, einen Einblick in die Pathophysiologie dieser Erkrankung zu gewinnen. Methodik: Im Rahmen dieser Übersicht wird die pathogenetische Bedeutung von Wachstumsfaktor-Rezeptoren (EGFR, c-erbB-2, c-erbB-3), Wachstumsfaktoren (EGF, TGF-α, Amphiregulin, Betacellulin, TGF-βs, FGFs) sowie von Genmutationen (p53, K-ras) und Adhäsionsmolekülen beim humanen Pankreaskarzinom dargestellt. Ergebnisse: In einer signifikanten Anzahl der Pankreaskarzinome sind Wachstumsfaktorrezeptoren (EGFR, c-erbB-2, c-erbB-3), Wachstumsfaktoren (EGF, TGF-α, Amphiregulin, Betacellulin, TGF-βs, FGFs) und Adhäsionsmoleküle (ICAM-1, ELAM-1) überexprimiert sowie Genmutationen (p53, K-ras) vorhanden. Allerdings sind nicht alle diese molekularen Veränderungen mit einem schnelleren Tumorwachstum und einer schlechteren Prognose nach Tumorresektion vergesellschaftet. Schlußfolgerungen: Molekulare Störungen in Pankreaskarzinomzellen tragen zum malignen Phänotyp bei. Diese Veränderungen erklären, warum die Pankreaskarzinomzellen schnell proliferieren und nur eine geringe Ansprechbarkeit auf adjuvante onkologische Behandlungen zeige

Das pT4-Pankreaskarzinom: Chirurgische und multimodale Behandlung

Zusammenfassung: Grundlagen: Die Resektion, unterstützt durch multimodale Therapieschemata, gilt auch beim T4-Pankreaskarzinom als einzige kurative Therapie. Methodik: Beim T4-Pankreaskarzinom muß häufig ein erweitertes Resektionsverfahren gewählt werden, das eine En-bloc-Entfernung des Tumors erlaubt und heute mit einer niederen Morbidität und Moralität vorgenommen werden kann. Der Stellenwert der Lymphknotendissektion bei diesen lokal fortgeschrittenen Pankreaskarzinomen ist nicht geklärt. Die hohe Lokalrezidivrate kann eventuell durch eine radikalere Lymphknotendissektion zusammen mit einer präoperativen, intraoperativen oder postoperativen kombinierten Chemotherapie verbessert werden. Ergebnisse: Die Ergebnisse multimodaler Therapieschemata zur Behandlung des Pankreaskarzinoms werden vorgestellt und der Stellenwert der einzelnen potentiell kurativen und palliativen Modalitäten diskutiert. Schlußfolgerungen: Obwohl der Einfluß auf Lokalrezidivraten und Überleben beim T4-Pankreaskarzinom noch nicht geklärt ist, scheint eine multimodale Behandlung bei der Gesamtgruppe der Patienten mit Pankreaskarzinom diesbezüglich bessere Resultate zu erzielen. Diese Resultate werden in Zukunft noch in prospektiv randomisiert durchgeführten Multicenter-Studien geklärt werde

The stress tensor of a quark moving through N=4 thermal plasma

We develop the linear equations that describe graviton perturbations of AdS_5-Schwarzschild generated by a string trailing behind an external quark moving with constant velocity. Solving these equations allows us to evaluate the stress tensor in the boundary gauge theory. Components of the stress tensor exhibit directional structures in Fourier space at both large and small momentum. We comment on the possible relevance of our results to relativistic heavy ion collisions.Comment: 33 pages, 5 figures. v2: improved low K discussion; other minor improvement

Activity of raltitrexed and gemcitabine in advanced pancreatic cancer

Background: Gemcitabine has evolved as standard therapy in advanced pancreatic cancer since the demonstration of a significant clinical benefit. Phase II trials have shown that gemcitabine can be successfully combined with thymidylate synthase (TS) inhibitors such as continuous-infusion 5-fluorouracil (5-FU). However, continuous-infusion 5-FU is inconvenient because of the need for a central venous access. The aim of this study was to assess the efficacy and safety of gemcitabine in combination with raltitrexed (Tomudex), a novel and selective TS inhibitor that has the advantage of a 3-weekly treatment interval and manageable toxicity. Patients and methods: Chemotherapy-naïve patients with measurable advanced pancreatic cancer were treated with raltitrexed 3 mg/m2 as a 15-min infusion on day 1 and gemcitabine 1000 mg/m2 on days 1 and 8, every 21 days. Results: Twenty-five eligible patients (17 male, eight female) with metastatic (21 patients) or locally advanced (four patients) disease entered the study. The median number of courses per patient was four (range 1-14). One patient was not evaluable for response. There were three partial remissions [12%; 95% confidence interval (CI) 2.6% to 31.2%] and nine stable disease situations (36%; 95% CI 18.0% to 57.5%), while the tumours of 12 patients (48%; 95% CI 27.8% to 68.7%) showed progressive disease after three treatment cycles. WHO grade 3/4 toxicity was rare and symptomatic in only one patient, who experienced grade 4 diarrhoea and grade 3 nausea and vomiting. Symptomatic benefit was seen in 12 patients. Median survival was 185 days (95% CI 129-241) with six patients still alive. Conclusions: The efficacy of raltitrexed plus gemcitabine is limited, but compares well with other chemotherapy treatment options in advanced pancreatic cancer. However, this combination is convenient and symptomatic toxicity is rare. Thus, raltitrexed and gemcitabine should be investigated further in combination with drugs interfering with specific molecular target

No-Drag String Configurations for Steadily Moving Quark-Antiquark Pairs in a Thermal Bath

We investigate the behavior of stationary string configurations on a five-dimensional AdS black hole background which correspond to quark-antiquark pairs steadily moving in an N=4 super Yang-Mills thermal bath. There are many branches of solutions, depending on the quark velocity and separation as well as on whether Euclidean or Lorentzian configurations are examined.Comment: references added; statements corrected; eliminated computation of jet quenching parameter from Wilson loop of [Liu, Rajagopal, Wiedemann, hep-th/0605178] using Euclidean string configurations since those authors advocate [hep-th/0607062, footnote 14] the use of spacelike Lorentzian string configurations instea

The curious case of large-N expansions on a (pseudo)sphere

We elucidate the large-N dynamics of one-dimensional sigma models with spherical and hyperbolic target spaces and find a duality between the Lagrange multiplier and the angular momentum. In the hyperbolic model we propose a new class of operators based on the irreducible representations of hyperbolic space. We also uncover unexpected zero modes which lead to the double scaling of the 1/N expansion and explore these modes using Gelfand-Dikiy equations.Comment: 18 pages, 3 figure