University of Vienna

About: University of Vienna is a education organization based out in Vienna, Austria. It is known for research contribution in the topics: Population & Context (language use). The organization has 44686 authors who have published 95840 publications receiving 2907492 citations.

Update of the preclinical situation of anticancer platinum complexes: novel design strategies and innovative analytical approaches.

Abstract: Research in the field of bioinorganic chemistry has been stimulated by the worldwide success of the anticancer drug cisplatin. 40 years after the first report about its biological activity, carboplatin and oxaliplatin are in routine clinical use today, whereas nedaplatin, lobaplatin, and heptaplatin (SKI2053R) are only approved in Japan, China, and South Korea, respectively. Up to now, about 35 platinum complexes entered clinical trials in order to circumvent the side-effects and the problem of tumor resistance to cisplatin. Additionally, improvement of tumor selectivity as well as the need for a broader spectrum of indications are the motivations for tremendous efforts in the development of novel anticancer platinum-based drugs. New synthetic strategies and innovative analytical approaches provide a basis for a deeper understanding of the pharmacological profile of cisplatin and analogues (biodistribution, clearance, detoxification, sideeffects, tumor specificity, cellular uptake, acquired or intrinsic resistance, platinum-DNA adduct removal by the cellular machinery) and give rise to a rational design of promising anticancer platinum coordination compounds. This article reviews the recent development of preclinical platinum complexes with interesting in vitro and in vivo tumor inhibiting properties. It focuses also on innovative synthetic strategies leading to novel classes of platinum complexes. A small part of the review is dedicated to new analytical approaches which have been supplied to or emerged in this field of research.

Entanglement purification for quantum communication

Abstract: The distribution of entangled states between distant locations will be essential for the future large-scale realization of quantum communication schemes such as quantum cryptography1,2 and quantum teleportation3. Because of unavoidable noise in the quantum communication channel, the entanglement between two particles is more and more degraded the further they propagate. Entanglement purification4,5,6,7 is thus essential to distil highly entangled states from less entangled ones. Existing general purification protocols4,5,6 are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Present realizations of CNOT gates are much too imperfect to be useful for long-distance quantum communication8. Here we present a scheme for the entanglement purification of general mixed entangled states, which achieves 50 per cent of the success probability of schemes based on the CNOT operation, but requires only simple linear optical elements. Because the perfection of such elements is very high, the local operations necessary for purification can be performed with the required precision. Our procedure is within the reach of current technology, and should significantly simplify the implementation of long-distance quantum communication.

Clock Synchronization in Distributed Real-Time Systems

Abstract: The generation of a fault-tolerant global time base with known accuracy of synchronization is one of the important operating system functions in a distributed real-time system. Depending on the types and number of tolerated faults, this paper presents upper bounds on the achievable synchronization accuracy for external and internal synchronization in a distributed real-time system. The concept of continuous versus instantaneous synchronization is introduced in order to generate a uniform common time base for local, global, and external time measurements. In the last section, the functions of a VLSI clock synchronization unit, which improves the synchronization accuracy and reduces the CPU load, are described. With this unit, the CPU overhead and the network traffic for clock synchronization in state-of-the-art distributed real-time systems can be reduced to less than 1 percent.

A survey on pickup and delivery problems

Abstract: This paper is the first part of a comprehensive survey on pickup and delivery problems. Basically, two problem classes can be distinguished. The first class, discussed in this paper, deals with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. This class is denoted as Vehicle Routing Problems with Backhauls (VRPB). Four subtypes can be considered, namely the Vehicle Routing Problem with Clustered Backhauls (VRPCB – all linehauls before backhauls), the Vehicle Routing Problem with Mixed linehauls and Backhauls (VRPMB – any sequence of linehauls and backhauls permitted), the Vehicle Routing Problem with Divisible Delivery and Pickup (VRPDDP – customers demanding delivery and pickup service can be visited twice), and the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP – customers demanding both services have to be visited exactly once). The second class, dealt with in the second part of this survey, refers to all those problems where goods are transported between pickup and delivery locations. These are the Pickup and Delivery Vehicle Routing Problem (PDVRP – unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP – paired pickup and delivery points), and the Dial-A-Ride Problem (DARP – passenger transportation between paired pickup and delivery points and user inconvenience taken into consideration). Single as well as multi vehicle versions of the mathematical problem formulations are given for all four VRPB types, the corresponding exact, heuristic, and metaheuristic solution methods are discussed.