Methods for direct determination of mitomycin C in aqueous solutions and in urine

Stripping voltammetry (SV) is used to quantitatively determine concentrations of the anti-neoplastic drug mitomycin C (MMC) alone and in mixtures with 5-fluorouracil and cisplatin, both of which are used in combined chemotherapy with MMC. If the accumulation is performed at the potentials of MMC reduction (-0.35 V vs. SCE), reduced MMC is strongly adsorbed at the electrode. It is possible to prepare a MMC-modified electrode, which, after a washing step, is transferred to the background electrolyte to determine MMC by voltammetry. This procedure, which is termed transfer stripping voltammetry (TSV), helps to eliminate interferences and can be applied for a direct determination of MMC alone or in mixtures with other drugs in urine

Investigations of the Mars Upper Atmosphere with ExoMars Trace Gas Orbiter

The Martian mesosphere and thermosphere, the region above about 60 km, is not the primary target of the ExoMars 2016 mission but its Trace Gas Orbiter (TGO) can explore it and address many interesting issues, either in-situ during the aerobraking period or remotely during the regular mission. In the aerobraking phase TGO peeks into thermospheric densities and temperatures, in a broad range of latitudes and during a long continuous period. TGO carries two instruments designed for the detection of trace species, NOMAD and ACS, which will use the solar occultation technique. Their regular sounding at the terminator up to very high altitudes in many different molecular bands will represent the first time that an extensive and precise dataset of densities and hopefully temperatures are obtained at those altitudes and local times on Mars. But there are additional capabilities in TGO for studying the upper atmosphere of Mars, and we review them briefly. Our simulations suggest that airglow emissions from the UV to the IR might be observed outside the terminator. If eventually confirmed from orbit, they would supply new information about atmospheric dynamics and variability. However, their optimal exploitation requires a special spacecraft pointing, currently not considered in the regular operations but feasible in our opinion. We discuss the synergy between the TGO instruments, specially the wide spectral range achieved by combining them. We also encourage coordinated operations with other Mars-observing missions capable of supplying simultaneous measurements of its upper atmosphere

A Game-theoretic Model of Attention in Social Networks

We model the economics of producing content in online social networks such as Facebook and Twitter. We propose a game-theoretic model within which we quantify inefficiencies from contributions by strategic users in online environments. Attention and information are assumed to be the main motivation for user contributions. We treat attention as a mechanism for sharing the profit from consuming information and introduce a general framework for analyzing dynamics of contributions in online environments. We analyze the proposed model and identify conditions for existence and efficient computation of pure-strategy Nash equilibrium. We prove a bicriteria bound on the price of anarchy; in particular we show that the social welfare from central control over level of contribution by users is no larger than the social welfare from strategic agents with twice as large consumption utilities. We then construct and analyze a family of production games that have an arbitrarily large price of anarchy. We also prove nonrobustness of the price of anarchy for a particular instance of the introduced family, establishing a distinction between the games studied here and network congestion games.

The W.M. Keck Telescope Segmented Primary Mirror Active Control System

The ten meter diameter primary mirror of the W. M. Keck Telescope is a mosaic of thirty-six hexagonal mirrors. An active control system stabilizes the primary mirror. The active control system uses 168 measurements of the relative positions of adjacent mirror segments and 3 measurements of the primary mirror position in the telescope structure to control the 108 degrees of freedom needed to stabilize the figure and position of the primary mirror. The components of the active control system are relative position sensors, electronics, computers, actuators that position the mirrors, and software. The software algorithms control the primary mirror, perform star image stacking, emulate the segments, store and fit calibration data, and locate hardware defects. We give an overview of the active control system, its functional requirements and test measurements. 12 refs

Stress and the individual: Evaluation of Type A personality

When we look for the criteria for causation of Type A behaviour for coronary heart disease, we lack the reproducibility, the predictability to a certain extent, a pathogenic mechanism and an animal model, all four ofthe eight recognized criteria for causal inference. The debate therefore is still wide open. © The Fellowship of Postgraduate Medicine, 1986.SCOPUS: ar.jinfo:eu-repo/semantics/publishe