Heterochromatin effects on the frequency and duration of LCR-mediated gene transcription

Organ transplantation is associated with an early bone loss that subsequently increases the risk of osteopenia and bone fractures. It is not known whether bone loss continues in long-term survivors, but persistent bone demineralization could further jeopardize an already diminished bone mass. To better define long-term bone status of kidney transplant recipients (KTR), we conducted cross-sectional and longitudinal evaluations of bone mineral density (BMD) in 70 KTR with a mean posttransplantation time of 8.1 years. BMD was determined by dual-energy X-ray absorptiometry and was repeated in 55 of the patients after a mean follow-up period of 22 +/- 5 months. Lumbar and femoral osteopenia, defined as a BMD lower than 2 standard deviations from mean value of sex- and age-matched controls, was present in 28.6% and 10.5% of patients, respectively. There was a significant negative correlation between cumulative prednisone dose and adjusted lumbar as well as femoral BMD (R = 0.45, P < 0.001 and R = 0.29, P < 0.05, respectively). Five patients had a vertebral BMD below a fracture threshold of 0.777 g/cm2. Vertebral fractures (VF) were found in four men and were associated with higher prednisone dosage (P < 0.05), larger cumulative prednisone dose (P < 0.05), and significantly lower BMD values. According to World Health Organization recent criteria for women, prevalences of lumbar and femoral osteopenia and lumbar and femoral osteoporosis in female patients reach 75%, 65%, 33%, and 10%, respectively. The longitudinal part of the study showed a persistent pathological lumbar demineralization process. Over the study period, BMD, expressed as a percentage of that of controls, decreased from 89 +/- 14% to 86 +/- 14% (P < 0.001). Annual change of bone mass was -1.7 +/- 2.8% per year. Accelerated vertebral bone loss (defined as a decrease of BMD, expressed as a percentage of that of controls, of more than 1% per year) was present in 56% of patients and was associated with higher prednisone dosage (P < 0.01). In conclusion, although VF are relatively infrequent in long-term survivors of renal transplantation, osteopenia is a frequent finding, and a substantial proportion of women present lumbar osteoporosis. An ongoing demineralization process of the spine is also demonstrated and probably contributes to long-term spinal osteoporosis incidence. Prednisone dosage remains the most constantly isolated risk factor.     

Design and implementation of high-speed buffered crossbars with efficient load balancing for multi-core SoCs

A large increase of the number of devices integrated in a single chip in conjunction with the significant demands of modern applications for performance has led the designers to a system development methodology based on integrating multiple pre-verified intellectual property cores. Yet, design productivity requirements push designers to focus on key micro-architectural solutions to manage more efficiently the scaling of multi-core SoCs as well as to increase the degree of design automation, particularly as rapid prototyping using reconfigurable computing is becoming mainstream. In this paper we present a novel interconnect architecture based on optimized components to efficiently manage SoCs that follow either a multi-core based approach or are built to support SIMD-style applications that can exploit the processing power of a pool of hardware resources; first we analyze the design of a crossbar featuring shared-memory combined input-crosspoint buffering as a solution for efficient implementation of on-chip interconnection; second we describe the design of a load-balancer featuring configurable proportional allocation of on-chip resources and in-order delivery as a solution for efficient scheduling and execution of processing tasks. The main focus of the paper is to describe and evaluate the mechanisms designed to distribute and manage data transfers so as to implement an efficient interconnection of the integrated cores and control access to available (either on-chip or off-chip) resources for the implementation of a number of embedded systems and applications. Each of these challenges is handled by the proposed architecture in an efficient way in terms of performance, cost in silicon and flexibility.     

p‐version of the generalized FEM using mesh‐based handbooks with applications to multiscale problems

In this paper, we analyse the p‐convergence of a new version of the generalized finite element method (generalized FEM or GFEM) which employs mesh‐based handbook functions which are solutions of boundary value problems in domains extracted from vertex patches of the employed mesh and are pasted into the global approximation by the partition of unity method (PUM). We show that the p‐version of our GFEM is capable of achieving very high accuracy for multiscale problems which may be impossible to solve using the standard FEM. We analyse the effect of the main factors affecting the accuracy of the method namely: (a) The data and the buffer included in the handbook domains, and (b) The accuracy of the numerical construction of the handbook functions. We illustrate the robustness of the method by employing as model problem the Laplacian in a domain with a large number of closely spaced voids. Similar robustness can be expected for problems of heat‐conduction and elasticity set in domains with a large number of closely spaced voids, cracks, inclusions, etc. Copyright © 2004 John Wiley & Sons, Ltd.     

Wireless Channel State-Aware and Adaptive Epidemic Dissemination in Ad Hoc Networks

Ad hoc networks are characterized by limited resources (e.g. energy, bandwidth). Efficient information dissemination while avoiding excessive energy cost can be achieved through the suitable design of a network. To this end we propose an information dissemination scheme which couples epidemic dissemination with adaptive modulation and coding (AMC). The proposed scheme tunes the message forwarding probability and the coding and modulation mode in order to achieve a balance between maximum coverage over the network and minimum energy expenditure. We achieve this based on the evaluation of suitably defined indicators related to the lower network layers and exploiting information on the current status of the wireless medium. Building on established previous AMC-related work, our simulation results indicate that our scheme brings significant improvement over non-adaptive approaches, comparable with other adaptive epidemic dissemination schemes. Our findings are quite promising for adaptive epidemic-based information dissemination schemes with a strong cross-layer component.     

Assessment of the cost and accuracy of the generalized FEM

In this paper, we address the cost versus accuracy capabilities for the generalized FEM (GFEM) which was developed in (Comput. Methods Appl. Mech. Eng. 2003; 192 :3109–3161, Int. J. Numer. Meth. Engng 2004; 60 :1639–1672, Ph.D. Thesis, Texas A&M University, College Station, TX, August 2003 (Advisor: T. Strouboulis)), and also the construction of two‐sided a posteriori error estimates, which can be used to assess the achieved accuracy at all levels of the method. Copyright © 2006 John Wiley & Sons, Ltd.     

Evaluation of optical core networks based on the CANON architecture

Clustering of nodes in optical networks has been proven to be an efficient way to serve end-to-end connectivity. However, clustering requires specific topological characteristics, or alternatively the introduction of significant alterations of an existing topology to achieve the expected performance improvements. The comparison of future dynamic optical networking technologies should therefore include in the set of initial assumptions, apart from the statistical properties of the traffic load, the network topology to draw conclusions regarding the efficiency as well as feasibility and scalability of the proposed solutions. In this article, we show how node clustering under the CANON architecture can be applied in real-life core networks and provide superior performance compared to conventional burst switching techniques in terms of blocking, resource utilization and power consumption.     

Efficient implementation of a frame aggregation unit for optical frame-based switching

Aggregating Ethernet frame or IP packet in large fixed-size frames allows for building scalable core network architectures. Classifying the arriving traffic based on destination core node information and quality of service parameters alleviates the need of performing table look-ups on packet basis. These advantages come at the cost of extra logic at the network egress, as regards implementation, and additional jitter due to the frame assembly process. This paper describes the efficient implementation of a frame aggregation unit that gathers Ethernet packets in G.709 containers, handles 10 Gb/s links, performs classification based on 24-byte headers, and includes a highly pipelined Queue Manager to cope with the considered rates while a specific scheduler controls the quality of service per core network flow. Based on the developed demonstrator, we provide results both as regards area and performance for an FPGA (field programmable gate array) Virtex-4 implementation as well as regarding the introduced jitter.     

Case Study in Protocol Validation: Validating an ATM Signalling Protocol

This paper discusses validation techniques for communication protocols and analyzes the practical use of selected validation techniques in an automated manner. A case study on validating the ATM (Asynchronous Transfer Mode) Signalling Protocol as specified by ITU-T in Q.2931 is used for this analysis. Different error classes are identified and validated. An assessment of the different validation techniques in terms of effort and quality of results is given. As a result of the case study, an evaluation of the Q.2931 SDL specification completes the paper. Received March 1998 / Accepted in revised form October 1998     

Identification of the glycosylation pattern of meat proteins in tissues from bovine myelin

A variant form of Creutzfeld–Jacob disease in humans is associated with the consumption of food contaminated with the bovine central neural system. This has focused attention on the need for procedures to detect tissues of the neural system in meat and meat products. A method was developed for the identification of myelin glycoproteins in bovine neural tissue. The glycosylated structures of glycoproteins in different protein mixtures from central nervous system (CNS) and peripheral nervous system (PNS) isolated from bovine myelin were identified by the specific lectin–glycoprotein reactions. Digoxigenin-labeled lectins bonded to the terminal glycoconjugate sequences of nine CNS glycoproteins ranging from 15 to 200 kDa and four PNS glycoproteins ranging from 22 to 105 kDa. Datura stramonium (DSA) recognized the epitope Galβ1–4GlcNAc by two CNS and three PNS glycoproteins. Maackia amurensis (MAA) recognized the epitope NeuAcα2–3Gal by four CNS and two PNS glycoproteins. The peanut Arachis hypogaea (PNA) reacted with the high molecular CNS glycoprotein (200 kDa) with the sequence Galβ1–3GalNAc. Galanthus nivalis (GNA) bonded to mannose subunits linked α1–3 and α1–6 by six CNS glycoproteins with molecular weights between 17 and 200 kDa. Four of these glycoproteins were recognized from monoclonal antibodies against the “HNK-1 epitope”.