Singular Potentials and Limit Cycles

We show that a central $1/r^n$ singular potential (with $n\geq 2$) is renormalized by a one-parameter square-well counterterm; low-energy observables are made independent of the square-well width by adjusting the square-well strength. We find a closed form expression for the renormalization-group evolution of the square-well counterterm.Comment: 15 pages LaTex, 5 eps figures, error in figures and text correcte

Angiotensin administration stimulates renal 11β-hydroxysteroid dehydrogenase activity in healthy men

Angiotensin administration stimulates renal 11β-hydroxysteroid dehydrogenase activity in healthy men.BackgroundWe examined whether acute administration of angiotensin modulates the activity of 11β-hydroxysteroid dehydrogenase (11βHSD), the intracellular enzyme catalyzing the interconversion between the hormonally active cortisol and inactive cortisone.MethodsTwenty-one male healthy subjects were examined after 1week of a low- and high-salt diet (50 and 200mmol/day, respectively). Separate infusions of angiotensin I (Ang I) and II (Ang II) were administered, both at rates of 4 and 8ng/kg/min. The ratios of tetrahydrocortisol + allotetrahydrocortisol/tetrahydrocortisone (THF + allo-THF/THE) and of free cortisol/free cortisone (UFF/UFE) in urine were measured as indices of overall 11βHSD set point and activity of renal 11βHSD type 2, respectively. Glomerular filtration rate (GFR) was measured by constant infusion of 125I-iothalamate.ResultsAng I and Ang II infusion dose-dependently increased mean arterial blood pressure (MAP) and plasma aldosterone, and decreased plasma renin activity (PRA) and GFR at both diets. Ang I and Ang II infusion resulted in a dose-dependent decrease in the excretion of UFF, UFE, and of the UFF/UFE ratio at both diets, without changing the urinary (THF + allo-THF)/THE ratio. Salt restriction did not affect these 11βHSD variables, but was accompanied by a decrease in UFF and UFE excretion.ConclusionThis study suggests that acute angiotensin administration stimulates the activity of 11βHSD type 2 in human kidney. Angiotensin might therefore exert a dual effect on the mineralocorticoid receptor (i.e., an indirect agonistic effect by increasing aldosterone availability and a direct or indirect antagonistic effect by stimulation of renal 11βHSD type 2 activity)

A Model Study of Discrete Scale Invariance and Long-Range Interactions

We investigate the modification of discrete scale invariance in the bound state spectrum by long-range interactions. This problem is relevant for effective field theory descriptions of nuclear cluster states and manifestations of the Efimov effect in nuclei. As a model system, we choose a one dimensional inverse square potential supplemented with a long-range Coulomb interaction. We study the renormalization and bound-state spectrum of the system as a function of the Coulomb interaction strength. Our results indicate, that the counterterm required to renormalize the inverse square potential alone is sufficient to renormalize the full problem. However, the breaking of the discrete scale invariance through the Coulomb interaction leads to a modified bound state spectrum. The shallow bound states are strongly influenced by the Coulomb interaction while the deep bound states are dominated by the inverse square potential.Comment: 8 pages, 6 figures, EPJ style, published versio

Nonlinear Realization of Chiral Symmetry on the Lattice

We formulate lattice theories in which chiral symmetry is realized nonlinearly on the fermion fields. In this framework the fermion mass term does not break chiral symmetry. This property allows us to use the Wilson term to remove the doubler fermions while maintaining exact chiral symmetry on the lattice. Our lattice formulation enables us to address non-perturbative questions in effective field theories of baryons interacting with pions and in models involving constituent quarks interacting with pions and gluons. We show that a system containing a non-zero density of static baryons interacting with pions can be studied on the lattice without encountering complex action problems. In our formulation one can also decide non-perturbatively if the chiral quark model of Georgi and Manohar provides an appropriate low-energy description of QCD. If so, one could understand why the non-relativistic quark model works.Comment: 34 pages, 2 figures, revised version to be published in J. High Energy Phys. (changes in the 1st paragraph, additional descriptions on the nature of the coordinate singularities in Sec.2, references added

A calculation of the QCD phase diagram at finite temperature, and baryon and isospin chemical potentials

We study the phases of a two-flavor Nambu-Jona-Lasinio model at finite temperature $T$, baryon and isospin chemical potentials: $\mu_{B}=(\mu_{u}+\mu_{d})/2$, $\mu_{I}=(\mu_{u}-\mu_{d})/2$. This study completes a previous analysis where only small isospin chemical potentials $\mu_{I}$ were consideredComment: 21 pages, 13 figures included, two more refernces adde

Monitoring storage induced changes in the platelet proteome employing label free quantitative mass spectrometry

Shelf life of platelet concentrates is limited to 5-7 days due to loss of platelet function during storage, commonly referred to as the platelet storage lesion (PSL). To get more insight into the development of the PSL, we used label free quantitative mass spectrometry to identify changes in the platelet proteome during storage. In total 2501 proteins were accurately quantified in 3 biological replicates on at least 1 of the 7 different time-points analyzed. Significant changes in levels of 21 proteins were observed over time. Gene ontology enrichment analysis of these proteins revealed that the majority of this set was involved in platelet degranulation, secretion and regulated exocytosis. Twelve of these proteins have been shown to reside in α-granules. Upon prolonged storage (13-16 days) elevated levels of α-2-macroglobulin, glycogenin and Ig μ chain C region were identified. Taken together this study identifies novel markers for monitoring of the PSL that may potentially also be used for the detection of "young" and "old" platelets in the circulation

Utility of TERT Promoter Mutations for Cutaneous Primary Melanoma Diagnosis

Telomerase reverse transcriptase (TERT) promoter mutations are commonly found in malignant melanomas but rare in melanocytic nevi. To assess its potential diagnostic utility for the distinction of melanoma from nevus, we determined the TERT promoter mutation status of 86 primary melanomas, 72 melanocytic nevi, and 40 diagnostically problematic melanocytic proliferations. Of the 86 melanomas, 67 (77.9%) were TERT-positive, defined as harboring a hotspot TERT promoter mutation at positions -124C>T, -124_125CC>TT, -138_139CC>TT, or -146C>T. Of the 72 nevi, only 1 (1.4%) was TERT-positive. Of the 40 diagnostically uncertain melanocytic proliferations, 2 (5.0%) were TERT-positive. TERT positivity as a test for melanoma versus nevus had an accuracy of 87.3% [95% confidence interval (CI), 81.1-92.1], a sensitivity of 77.9% (95% CI, 68.9-85.4), a specificity of 98.6% (95% CI, 95.8-100), a positive predictive value of 98.5% (95% CI, 95.6-100), and a negative predictive value of 78.9% (95% CI, 72.6-85.4). Our results indicate that hotspot TERT promoter mutation status may be a useful ancillary parameter for the diagnosis of melanoma. In particular, the high specificity of these mutations for melanoma indicates the presence of a TERT promoter mutation in a melanocytic neoplasm associated with diagnostic controversy, or uncertainty should increase concern for a melanoma

Numerical Portrait of a Relativistic BCS Gapped Superfluid

We present results of numerical simulations of the 3+1 dimensional Nambu - Jona-Lasinio (NJL) model with a non-zero baryon density enforced via the introduction of a chemical potential mu not equal to 0. The triviality of the model with a number of dimensions d>=4 is dealt with by fitting low energy constants, calculated analytically in the large number of colors (Hartree) limit, to phenomenological values. Non-perturbative measurements of local order parameters for superfluidity and their related susceptibilities show that, in contrast to the 2+1 dimensional model, the ground-state at high chemical potential and low temperature is that of a traditional BCS superfluid. This conclusion is supported by the direct observation of a gap in the dispersion relation for 0.5<=(mu a)<=0.85, which at (mu a)=0.8 is found to be roughly 15% the size of the vacuum fermion mass. We also present results of an initial investigation of the stability of the BCS phase against thermal fluctuations. Finally, we discuss the effect of splitting the Fermi surfaces of the pairing partners by the introduction of a non-zero isospin chemical potential.Comment: 41 pages, 19 figures, uses axodraw.sty, v2: minor typographical correction

Identification of a Robust Methylation Classifier for Cutaneous Melanoma Diagnosis

Early diagnosis improves melanoma survival, yet the histopathological diagnosis of cutaneous primary melanoma can be challenging, even for expert dermatopathologists. Analysis of epigenetic alterations, such as DNA methylation, that occur in melanoma can aid in its early diagnosis. Using a genome-wide methylation screening, we assessed CpG methylation in a diverse set of 89 primary invasive melanomas, 73 nevi, and 41 melanocytic proliferations of uncertain malignant potential, classified based on interobserver review by dermatopathologists. Melanomas and nevi were split into training and validation sets. Predictive modeling in the training set using ElasticNet identified a 40-CpG classifier distinguishing 60 melanomas from 48 nevi. High diagnostic accuracy (area under the receiver operator characteristic curve = 0.996, sensitivity = 96.6%, and specificity = 100.0%)was independently confirmed in the validation set (29 melanomas, 25 nevi)and other published sample sets. The 40-CpG melanoma classifier included homeobox transcription factors and genes with roles in stem cell pluripotency or the nervous system. Application of the 40-CpG melanoma classifier to the diagnostically uncertain samples assigned melanoma or nevus status, potentially offering a diagnostic tool to assist dermatopathologists. In summary, the robust, accurate 40-CpG melanoma classifier offers a promising assay for improving primary melanoma diagnosis

Characterization of the CpG Island Hypermethylated Phenotype Subclass in Primary Melanomas

Cutaneous melanoma can be lethal even if detected at an early stage. Epigenetic profiling may facilitate the identification of aggressive primary melanomas with unfavorable outcomes. We performed clustering of whole-genome methylation data to identify subclasses that were then assessed for survival, clinical features, methylation patterns, and biological pathways. Among 89 cutaneous primary invasive melanomas, we identified three methylation subclasses exhibiting low methylation, intermediate methylation, or hypermethylation of CpG islands, known as the CpG island methylator phenotype (CIMP). CIMP melanomas occurred as early as tumor stage 1b and, compared with low-methylation melanomas, were associated with age at diagnosis ≥65 years, lentigo maligna melanoma histologic subtype, presence of ulceration, higher American Joint Committee on Cancer stage and tumor stage, and lower tumor-infiltrating lymphocyte grade (all P < 0.05). Patients with CIMP melanomas had worse melanoma-specific survival (hazard ratio = 11.84; confidence interval = 4.65‒30.20) than those with low-methylation melanomas, adjusted for age, sex, American Joint Committee on Cancer stage, and tumor-infiltrating lymphocyte grade. Genes hypermethylated in CIMP compared with those in low-methylation melanomas included PTEN, VDR, PD-L1, TET2, and gene sets related to development/differentiation, the extracellular matrix, and immunity. CIMP melanomas exhibited hypermethylation of genes important in melanoma progression and tumor immunity, and although present in some early melanomas, CIMP was associated with worse survival independent of known prognostic factors