11,251 research outputs found
Congenital Adrenal Hyperplasia: A Case Report with Premature Teeth Exfoliation and Bone Resorption
Congenital adrenal hyperplasia (CAH) is an inherited autosomal recessive disorder characterized by insufficient production of cortisol. The aim of this case report was to present a child with CAH, premature exfoliation of primary teeth and accelerated eruption of his permanent teeth related to bone resorption. A 4.5-year-old Caucasian boy with CAH and long-term administration of glucocorticoids was referred for dental restoration. Clinical examination revealed primary molars with worn stainless steel crowns, severe attrition of the upper canines, and absence of the upper incisors. Before the completion of treatment, abnormal mobility of the first upper primary molars and the lower incisors was detected, and a few days later the teeth exfoliated prematurely. Histologic examination revealed normal tooth structure. Alkaline phosphatase and blood cells values were normal. Eruption of the permanent dentition was also accelerated. Tooth mobility was noticed in the permanent teeth as soon as they erupted, along with bone destruction. Examination revealed an elevated level of receptor activator of nuclear factor-kB ligand and lower-than-normal osteoprotegerin and vitamin D levels. The patient was treated with vitamin D supplements, and his teeth have been stable ever since. CAH is a serious chronic disorder appearing in children with accelerated dental development and possibly premature loss of primary teeth
Static potential in scalar QED with non-minimal coupling
Here we compute the static potential in scalar at leading order in
. We show that the addition of a non-minimal coupling of Pauli-type
(\eps j^{\mu}\partial^{\nu}A^{\alpha}), although it breaks parity, it does
not change the analytic structure of the photon propagator and consequently the
static potential remains logarithmic (confining) at large distances. The
non-minimal coupling modifies the potential, however, at small charge
separations giving rise to a repulsive force of short range between opposite
sign charges, which is relevant for the existence of bound states. This effect
is in agreement with a previous calculation based on Mller
scattering, but differently from such calculation we show here that the
repulsion appears independently of the presence of a tree level Chern-Simons
term which rather affects the large distance behavior of the potential turning
it into constant.Comment: 13 pages, 3 figure
Calculation of the Effective Stopping Power of Ions Generated by Neutrons in Tissue Constituents
This paper reports the calculation of stopping powers of heavy charged particles generated by neutrons in four-element
tissue constituents for particle energies from 0.1 keY to 1.0 MeV. At low projectile energies of less than 30 keV/amu where
the nuclear stopping phenomenon is more dominant than the electronic stopping phenomenon, the effective stopping power
values are higher than the continuous slowing-down approximation (CSDA) values, from which the deviation is dependent
upon the target mass and the energy and mass of the projectiles
Overexpression of hedgehog signaling is associated with epidermal tumor formation in vitamin D receptor-null mice.
The vitamin D receptor (VDR) ligand, 1,25 dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), reduces proliferation and enhances differentiation, and thus has been investigated for a role in preventing or treating cancer. Mice deficient for the VDR display a hyperproliferative response in the hair follicle and epidermis and decreased epidermal differentiation. Unlike their wild-type littermates, when treated with 7,12 dimethylbenzanthracene (DMBA) or UVB, they develop skin tumors, including some characteristic of overexpression of the hedgehog (Hh) pathway. Both the epidermis and utricles of the VDR-null animals overexpress elements of the Hh pathway (sonic hedgehog (Shh) 2.02-fold, patched1 1.58-fold, smoothened 3.54-fold, glioma-associated oncogene homolog (Gli)1 1.17-fold, and Gli2 1.66-fold). This overexpression occurs at an age (11 weeks) at which epidermal hyperproliferation is most visible and is spatially controlled in the epidermis. DMBA- or UVB-induced tumors in the VDR-null mice also overexpress elements of this pathway. Moreover, 1,25(OH)(2)D(3) downregulates the expression of some members of the Hh pathway in an epidermal explants culture system, suggesting a direct regulation by 1,25(OH)(2)D(3). Our results suggest that increased expression of Shh in the keratinocytes of the VDR-null animal activates the Hh pathway, predisposing the skin to the development of both malignant and benign epidermal neoplasms
Impeded Growth of Magnetic Flux Bubbles in the Intermediate State Pattern of Type I Superconductors
Normal state bubble patterns in Type I superconducting Indium and Lead slabs
are studied by the high resolution magneto-optical imaging technique. The size
of bubbles is found to be almost independent of the long-range interaction
between the normal state domains. Under bubble diameter and slab thickness
proper scaling, the results gather onto a single master curve. On this basis,
in the framework of the "current-loop" model [R.E. Goldstein, D.P. Jackson and
A.T. Dorsey, Phys. Rev. Lett. 76, 3818 (1996)], we calculate the equilibrium
diameter of an isolated bubble resulting from the competition between the
Biot-and-Savart interaction of the Meissner current encircling the bubble and
the superconductor-normal interface energy. A good quantitative agreement with
the master curve is found over two decades of the magnetic Bond number. The
isolation of each bubble in the superconducting matrix and the existence of a
positive interface energy are shown to preclude any continuous size variation
of the bubbles after their formation, contrary to the prediction of mean-field
models.Comment: \'{e}quipe Nanostructures Quantique
Consistently computing the K -> pi long distance weak transition
First we extract the long-distance (LD) weak matrix element from certain data
and give compatible theoretical estimates. We also link this LD scale to the
single-quark-line (SQL) transition scale and then test the latter SQL scale
against the decuplet weak decay amplitude ratio. Finally, we study LD decay.
All of these experimental and theoretical values are in good agreement. We
deduce an average value from eleven experimental determinations compared to the
theoretical SQL values average.Comment: 19 pages, 9 figures minor change to the Conclusions and abstract
sectio
Recommended from our members
Binding to medium and long chain fatty acyls is a common property of HEAT and ARM repeat modules.
Covalent post-translational modification (PTM) of proteins with acyl groups of various carbon chain-lengths regulates diverse biological processes ranging from chromatin dynamics to subcellular localization. While the YEATS domain has been found to be a prominent reader of acetylation and other short acyl modifications, whether additional acyl-lysine reader domains exist, particularly for longer carbon chains, is unclear. Here, we employed a quantitative proteomic approach using various modified peptide baits to identify reader proteins of various acyl modifications. We discovered that proteins harboring HEAT and ARM repeats bind to lysine myristoylated peptides. Recombinant HEAT and ARM repeats bind to myristoylated peptides independent of the peptide sequence or the position of the myristoyl group. Indeed, HEAT and ARM repeats bind directly to medium- and long-chain free fatty acids (MCFA and LCFA). Lipidomic experiments suggest that MCFAs and LCFAs interact with HEAT and ARM repeat proteins in mammalian cells. Finally, treatment of cells with exogenous MCFAs and inhibitors of MCFA-CoA synthases increase the transactivation activity of the ARM repeat protein β-catenin. Taken together, our results suggest an unappreciated role for fatty acids in the regulation of proteins harboring HEAT or ARM repeats
Quantum equivalence between the self-dual and the Maxwell-Chern-Simons models nonlinearly coupled to U(1) scalar fields
The use of master actions to prove duality at quantum level becomes
cumbersome if one of the dual fields interacts nonlinearly with other fields.
This is the case of the theory considered here consisting of U(1) scalar fields
coupled to a self-dual field through a linear and a quadratic term in the
self-dual field. Integrating perturbatively over the scalar fields and deriving
effective actions for the self-dual and the gauge field we are able to
consistently neglect awkward extra terms generated via master action and
establish quantum duality up to cubic terms in the coupling constant. The
duality holds for the partition function and some correlation functions. The
absence of ghosts imposes restrictions on the coupling with the scalar fields.Comment: 13 pages, no figure
Constraints on Higher-Order Perturbative Corrections in Semileptonic Decays from Residual Renormalization-Scale Dependence
The constraint of a progressive decrease in residual renormalization scale
dependence with increasing loop order is developed as a method for obtaining
bounds on unknown higher-order perturbative corrections to
renormalization-group invariant quantities. This technique is applied to the
inclusive semileptonic process (explicitly known to
two-loop order) to obtain bounds on the three- and four-loop perturbative
coefficients that are not accessible via the renormalization group. Using the
principle of minimal sensitivity, an estimate is obtained for the perturbative
contributions to that incorporates
theoretical uncertainty from as-yet-undetermined higher order QCD corrections.Comment: latex2e using amsmath, 8 pages, 4 embedded eps figures. Revised
version contains an additional figure and accompanying revision
Supervised Learning in Multilayer Spiking Neural Networks
The current article introduces a supervised learning algorithm for multilayer
spiking neural networks. The algorithm presented here overcomes some
limitations of existing learning algorithms as it can be applied to neurons
firing multiple spikes and it can in principle be applied to any linearisable
neuron model. The algorithm is applied successfully to various benchmarks, such
as the XOR problem and the Iris data set, as well as complex classifications
problems. The simulations also show the flexibility of this supervised learning
algorithm which permits different encodings of the spike timing patterns,
including precise spike trains encoding.Comment: 38 pages, 4 figure
- …