Bloom syndrome cells undergo p53-dependent apoptosis and delayed assembly of BRCA1 and NBS1 repair complexes at stalled replication forks

Bloom syndrome (BS) is a hereditary disorder characterized by pre- and postnatal growth retardation, genomic instability, and cancer. BLM, the gene defective in BS, encodes a DNA helicase thought to participate in genomic maintenance. We show that BS human fibroblasts undergo extensive apoptosis after DNA damage specifically when DNA replication forks are stalled. Damage during S, but not G1, caused BLM to rapidly form foci with gammaH2AX at replication forks that develop DNA breaks. These BLM foci recruited BRCA1 and NBS1. Damaged BS cells formed BRCA1/NBS1 foci with markedly delayed kinetics. Helicase-defective BLM showed dominant-negative activity with respect to apoptosis, but not BRCA1/NBS1 recruitment, suggesting catalytic and structural roles for BLM. Strikingly, inactivation of p53 prevented the death of damaged BS cells and delayed recruitment of BRCA1/NBS1. These findings suggest that BLM is an early responder to damaged replication forks. Moreover, p53 eliminates cells that rapidly assemble BRCA1/NBS1 without BLM, suggesting that BLM is essential for timely BRCA1/NBS1 function.     

Opposite-channel-based charge injection in SOI MOSFET's under hotcarrier stress

By operating one channel of a typical SOI MOSFET in avalanche while keeping the opposite channel accumulated, charge injection into the opposite gate takes place. Three independent experiments are described that demonstrate the occurrence of this opposite-channel based charge injection. The experimental results are in agreement with PISCES numerical simulations     

EEG signal preprocessing for biometric recognition

Electroencephalography (EEG) has been recently investigated as a biometric modality for automatic people recognition purposes. Several studies have shown that brain signals possess subject-specific traits that allow distinguishing people. Nonetheless, extracting discriminative characteristics from EEG recordings may be a challenging task, due to the significant presence of artifacts in the acquired data. In order to cope with such issue, in this paper we evaluate the effectiveness of some preprocessing techniques in automatically removing undesired EEG contributions, with the aim of improving the achievable recognition rates. Specifically, methods based on blind source separation and sample entropy estimation are here investigated. An extensive set of experimental tests, performed over a large database comprising recordings taken from 50 healthy subjects during three distinct sessions spanning a period of about one month, in both eyes-closed and eyes-open conditions, is carried out to analyze the performance of the proposed approaches.     

Artistic edge and corner enhancing smoothing.

Two important visual properties of paintings and painting-like images are the absence of texture details and the increased sharpness of edges as compared to photographic images. Painting-like artistic effects can be achieved from photographic images by filters that smooth out texture details, while preserving or enhancing edges and corners. However, not all edge preserving smoothers are suitable for this purpose. We present a simple nonlinear local operator that generalizes both the well known Kuwahara filter and the more general class of filters known in the literature as "criterion and value filter structure." This class of operators suffers from intrinsic theoretical limitations which give rise to a dramatic instability in presence of noise, especially on shadowed areas. Such limitations are discussed in the paper and overcome by the proposed operator. A large variety of experimental results shows that the output of the proposed operator is visually similar to a painting. Comparisons with existing techniques on a large set of natural images highlight conditions on which traditional edge preserving smoothers fail, whereas our approach produces good results. In particular, unlike many other well established approaches, the proposed operator is robust to degradations of the input image such as blurring and noise contamination.     

Fundamentals of cell proliferation: control of the cell cycle

Cell proliferation in higher eukaryotes is controlled by the extracellular environment and the state of differentiation. Many cells exist in a nondividing growth state termed quiescence. Some quiescent cells cannot proliferate and are said to be terminally differentiated. Others can be stimulated to divide in response to environmental signals or when cell replacement is needed. Finally, some cells undergo continual proliferation and differentiation. Growth regulatory factors generally act at specific stages of the cell cycle, most commonly during the first gap phase of the cell cycle. Once cells initiate DNA synthesis, they are generally committed to complete DNA replication. After DNA synthesis, additional signals determine whether cells in the last gap phase proceed through mitosis. In recent years, genes that appear to be critical for progression through the first two gap phases have been identified. Many are proto-oncogenes and therefore can neoplastically transform certain cells when mutated or inappropriately expressed. Growth factors that stimulate proliferation induce the expression of several proto-oncogenes; growth inhibitory factors often suppress proto-oncogene expression. As cells differentiate, the response to extracellular factors changes. In many cases, this may be due to intracellular controls that alter the response of certain proto-oncogenes to external signals.     

Subclavian vein stenosis: a potentially serious complication in chronic hemodialysis patients with permanent cardiac pacemakers

We report on two hemodialyzed patients in whom subclavian and brachiocephalic vein stenosis secondary to permanent cardiac pacemakers led to massive congestive edema of the same arm after arteriovenous fistula/grafts were created. Therapeutic solutions regarding hemodialysis access are discussed in these patients with permanent pacemakers requiring hemodialysis.     

Decomposing growth in a multiregional I-O framework

Since the pioneering work of Wassilly Leontief, a remarkable amount of theoretical and empirical work has continuously supported Input-Output modelling. In particular, the peculiar structure of dynamic input-output (I-O) model have originated, in numerous fields ranging from mathematical economics to system theory, an abundance of contributes. This paper deals with the computational problem of managing regional growth within a dynamic multiregional input-output model. Starting from the basic matrices of technological capital and trade coefficients, the regional components associated to a given group of regions are appropriately recognised and separated. A numerical example, based on the Italian case, is also discussed.An earlier of this paper was presented at the Thirty-fourth Annual Meeting of Western Regional Science Association in San Diego and has benefitted from comments during the conference. The authors are grateful for suggestions rendered by the anonymous referees. They also wish to thank Prof. G. Hewings and P.R. Israilevich for their useful comments and suggestions.     

Frontiers in lymphatic microsurgery

The Authors report an overview on the modern surgical treatment of peripheral lymphoedema. The aim of lymphatic microsurgical operations is to drain the lymph either toward the venous circulation (lympho-venous shunts) or the lymphatic collectors above the obstacle to the lymph flow, with the interposition of lymphatic or venous grafts (lymphatic-venous-lymphatic plasty). Selection of candidate patients for lymphatic microsurgery is based on an adequate diagnostic investigation, which includes above all lymphoscintigraphy, conventional oil contrast lymphangiography, Doppler venous flowmetry and manometry, and, if necessary (angiodysplasias), an accurate study also of the artery circulation. The clinical outcome of lymphatic microsurgery, assessed by water volumetry and lymphangioscintigraphy, performed at variable distance of time from operations till over 5 years after surgery, shows a significant reduction of edema volume and improvement of lymph flow in all patients and that the more precocious the microsurgical treatment the better the results.     

High field RF superconductivity: To pulse or not to pulse?

Experimental data on the behavior of superconductors under the application of RF fields of amplitude comparable to their critical fields are sporadic and not always consistent. In many cases the field level at which breakdown in superconducting RF cavities should be expected has not been clearly established. Tests conducted with very short (sim1mus) RF pulses indicate that in this mode of operation fields close to the critical values can be consistently reached in superconducting cavities without breakdown. The advantages and disadvantages of the pulsed method are discussed compared to those of the more standard continuous wave (cw) systems.