Severe Dengue Is Associated with Consumption of von Willebrand Factor and Its Cleaving Enzyme ADAMTS-13

Severe dengue infections are characterized by thrombocytopenia, clinical bleeding and plasma leakage. Activation of the endothelium, the inner lining of blood vessels, leads to the secretion of storage granules called Weibel Palade bodies (WPBs). We demonstrated that severe dengue in Indonesian children is associated with a strong increase in plasma levels of the WPB constituents von Willebrand factor (VWF), VWF propeptide and osteoprotegerin (OPG). An increased amount of the hemostatic protein VWF was in a hyperreactive, platelet binding conformation, and this was most pronounced in the children who died. VWF levels at enrollment were lower than expected from concurrent VWF propeptide and OPG levels and VWF levels did not correlate well with markers of disease severity. Together, this suggests that VWF is being consumed during severe dengue. Circulating levels of the VWF-cleaving enzyme ADAMTS-13 were reduced. VWF is a multimeric protein and a subset of children had a decrease in large and intermediate VWF multimers at discharge. In conclusion, severe dengue is associated with exocytosis of WPBs with consumption of VWF and low ADAMTS-13 activity levels. This may contribute to the thrombocytopenia and complications of dengue

Complexity of Min-Max Subsequence Problems

We determine the computational complexity of the problem of ordering a set of n numbers into a sequence as well as the problem of ordering them into a cycle, such that the maximum sum of k successive numbers is minimal. The former problem arises in effectively storing multimedia data on multi-zone hard disks

Min-Max Subsequence Problems in Multi-Zone Disk Recording

We study the problem of ordering a collection of n numbers such that the maximum sum of k successive numbers is minimized. The problem occurs in the design of video servers and in-home hard disk recorders used for storage of video files. By alternately assigning the successive data blocks of a video file to the different zones of a hard disk one can guarantee a higher transfer rate over a given period of time than otherwise can be guaranteed

On the Guaranteed Throughput of Multi-Zone Disks

We derive the guaranteed throughput of a multi-zone disk that repeatedly handles batches of n requests of constant size. Using this guaranteed throughput in the design of multimedia systems, one can admit more streams or get smaller buffer requirements and guaranteed response times than when an existing lower bound is used. We consider the case that nothing can be assumed about the location of the requests on the disk. Furthermore, we assume that successive batches are handled one after the other, where the n requests in a batch are retrieved using a SCAN-based sweep strategy. We show that we only have to consider two successive batches to determine the guaranteed throughput. Using this, we can compute the guaranteed throughput by determining a maximumweighted path in a directed acyclic graph in O(z ) time, where z max is the number of zones of the disk

Theoretical aspects of local search

Local search has been applied successfully to a diverse collection of optimization problems. It's appreciated for its basic conceptual foundation, its general applicability, and its power to serve as a source for new search paradigms. The typical characteristics of combinatorial optimization problems to which local search can be applied, its relation to complexity theory, and the combination with randomized search features have led to a wealth of interesting theoretical results. However, these results are scattered throughout the literature. This is the first book that presents a large collection of theoretical results in a consistent manner, thus providing the reader with a coherent overview of the achievements obtained so far, but also serving as a source of inspiration for the development of novel results in the challenging field of local search

Cryptanalysis of White-Box DES Implementations with Arbitrary External Encodings

At DRM 2002, Chow et al. [4] presented a method for implementing the DES block cipher such that it becomes hard to extract the embedded secret key in a white-box attack context. In such a context, an attacker has full access to the implementation and its execution environment. In order to provide an extra level of security, an implementation shielded with external encodings was introduced by Chow et al. and improved by Link and Neumann [10]. In this paper, we present an algorithm to extract the secret key from such white-box DES implementations. The cryptanalysis is a differential attack on obfuscated rounds, and works regardless of the shielding external encodings that are applied. The cryptanalysis has a average time complexity of 214 and a negligible space complexity. © Springer-Verlag Berlin Heidelberg 2007.status: publishe