Effect of Disorder and Notches on Crack Roughness

We analyze the effect of disorder and notches on crack roughness in two dimensions. Our simulation results based on large system sizes and extensive statistical sampling indicate that the crack surface exhibits a universal local roughness of $\zeta_{loc} = 0.71$ and is independent of the initial notch size and disorder in breaking thresholds. The global roughness exponent scales as $\zeta = 0.87$ and is also independent of material disorder. Furthermore, we note that the statistical distribution of crack profile height fluctuations is also independent of material disorder and is described by a Gaussian distribution, albeit deviations are observed in the tails.Comment: 6 pages, 6 figure

Measuring functional renormalization group fixed-point functions for pinned manifolds

Exact numerical minimization of interface energies is used to test the functional renormalization group (FRG) analysis for interfaces pinned by quenched disorder. The fixed-point function R(u) (the correlator of the coarse-grained disorder) is computed. In dimensions D=d+1, a linear cusp in R''(u) is confirmed for random bond (d=1,2,3), random field (d=0,2,3), and periodic (d=2,3) disorders. The functional shocks that lead to this cusp are seen. Small, but significant, deviations from 1-loop FRG results are compared to 2-loop corrections. The cross-correlation for two copies of disorder is compared with a recent FRG study of chaos.Comment: 4 pages, 4 figure

Clinical and Molecular Features of Ewing Sarcoma in a Patient with Triple-X Syndrome

A case of Ewing sarcoma in a 16-year-old girl with 47 XXXc karyotype is reporte

Congenital infiltrating lipoma of the upper limb in a patient with von Willebrand disease

Infiltrating lipoma is a rare variety of lipoma, characterized by an infiltration of the adipose tissue of the muscles. Infiltrating lipomas are usually classified in two groups: intermuscular infiltrating lipoma and intramuscular infiltrating lipoma. Most are acquired, and they usually appear in middle-aged individuals. Exceptionally, they are congenital. In such cases they are not related to other diseases. We report an 8-year-old boy with a congenital infiltrating lipoma of the upper limb and von Willebrand disease. Both diseases are linked to an alteration in chromosome 12, but this clinical association seems to be random rather than causal

Insuficiencia respiratoria neonatal asociada a mutación en el gen de la proteína C del surfactante

La insuficiencia respiratoria en el recién nacido a término durante las primeras semanas de vida extrauterina es una situación poco frecuente. Entre sus causas se incluyen las enfermedades difusas del intersticio pulmonar, un grupo heterogéneo de enfermedades, la mayoría idiopáticas, caracterizadas por infiltrados difusos, alteraciones funcionales de tipo restrictivo y afectación del intercambio gaseoso. Una forma de enfermedad pulmonar intersticial que puede afectar a lactantes, niños o adultos jóvenes es la que se asocia al déficit congénito de proteínas B o C del surfactante pulmonar. En estos casos los procesos inflamatorios que evolucionan hacia la fibrosis pulmonar están precedidos por la acumulación de material proteináceo en el alvéolo. Se indagó la presencia de mutaciones en los genes de las proteínas B y C del surfactante en una familia española en la cual dos lactantes presentaron insuficiencia respiratoria progresiva desde el nacimiento, con alteraciones radiológicas y anatomopatológicas compatibles con enfermedad del intersticio pulmonar, y el padre refería historia de problemas respiratorios desde la infancia. Se encontró que los dos hermanos de esta familia afectados por la enfermedad presentaban una expresión anómala del precursor de la proteína C del surfactante y concentraciones muy bajas de proteína madura. Se describe además una mutación nueva en el gen que codifica la proteína C del surfactante y que cosegrega con la enfermedad en esta familia

Morphology of two dimensional fracture surface

We consider the morphology of two dimensional cracks observed in experimental results obtained from paper samples and compare these results with the numerical simulations of the random fuse model (RFM). We demonstrate that the data obey multiscaling at small scales but cross over to self-affine scaling at larger scales. Next, we show that the roughness exponent of the random fuse model is recovered by a simpler model that produces a connected crack, while a directed crack yields a different result, close to a random walk. We discuss the multiscaling behavior of all these models.Comment: slightly revise

Ewing Family Tumors: Potential Prognostic Value of Reverse-Transcriptase Polymerase Chain Reaction Detection of Minimal Residual Disease in Peripheral Blood Samples

In more than 95% of patients, the Ewing family of tumors (ET) has chimeric transcripts caused by fusion of the EWS gene to either FLI1 or ERG. The presence of specific EWS-FLI1 or EWS-ERG transcripts in peripheral blood (PB) samples of patients being treated for ET was prospectively evaluated, and these data were correlated to their clinical status. The authors studied 113 PB samples from 28 patients with ET. Treatment included chemotherapy, radiotherapy, and surgical excision of tumor after induction therapy. PB samples were taken prospectively at least 2 weeks after resection of tumor. Nested reverse-transcriptase polymerase chain reaction (RT-PCR) followed by Southern blot was performed in all samples. Resected tumors were reviewed for the degree of response to chemotherapy and volume. Seventy-seven PB samples from 28 patients had EWS-FLI1/ERG transcripts. In 11 patients, PB samples became negative with treatment, and, in 5 of them, the samples remained negative throughout the study. Samples taken during progression were always positive and, in 4 patients, became positive before progression was clinically evident. All patients with transcripts other than EWS-FLI1 type 1 (n = 3) died from tumor progression. This is a sensitive assay to monitor circulating tumor cells in Ewing tumors. The preliminary data suggest that progression is preceded by positive samples and may be related to specific transcript types

Size effects in statistical fracture

We review statistical theories and numerical methods employed to consider the sample size dependence of the failure strength distribution of disordered materials. We first overview the analytical predictions of extreme value statistics and fiber bundle models and discuss their limitations. Next, we review energetic and geometric approaches to fracture size effects for specimens with a flaw. Finally, we overview the numerical simulations of lattice models and compare with theoretical models.Comment: review article 19 pages, 5 figure

Characterization of human mesenchymal stem cells from Ewing sarcoma patients. Pathogenetic implications

Ewing Sarcoma (EWS) is a mesenchymal-derived tumor that generally arises in bone and soft tissue. Intensive research regarding the pathogenesis of EWS has been insufficient to pinpoint the early events of Ewing sarcomagenesis. However, the Mesenchymal Stem Cell (MSC) is currently accepted as the most probable cell of origin

Crack Roughness in the 2D Random Threshold Beam Model

We study the scaling of two-dimensional crack roughness using large scale beam lattice systems. Our results indicate that the crack roughness obtained using beam lattice systems does not exhibit anomalous scaling in sharp contrast to the simulation results obtained using scalar fuse lattices. The local and global roughness exponents ($\zeta_{loc}$ and $\zeta$, respectively) are equal to each other, and the two-dimensional crack roughness exponent is estimated to be $\zeta_{loc} = \zeta = 0.64 \pm 0.02$. Removal of overhangs (jumps) in the crack profiles eliminates even the minute differences between the local and global roughness exponents. Furthermore, removing these jumps in the crack profile completely eliminates the multiscaling observed in other studies. We find that the probability density distribution $p(\Delta h(\ell))$ of the height differences $\Delta h(\ell) = [h(x+\ell) - h(x)]$ of the crack profile obtained after removing the jumps in the profiles follows a Gaussian distribution even for small window sizes ($\ell$).Comment: 8 pages, 6 figure