DISCWorld: an environment for service-based matacomputing

We describe our DISCWorld system for wide-area, high-performance metacomputing in which we adopt a high-level, service-based approach. Users’ client programs request combinations of services from a set of server nodes which communicate at a peer-based level. DISCWorld is a constrained metacomputing system, running only the service operations its participating resource administrators have chosen to provide and advertise, and provides a common integration environment for clients to access these services and developers to make them available. We discuss our software architecture and experiences building DISCWorld using Java and CORBA components, and the associated research issues for metacomputing that we are addressing.     

Determination of platinum in blood by adsorptive voltammetry

This work describes a sensitive method for the determination of platinum in blood, which can be used for determining the natural levels of platinum in human blood, for monitoring patients treated with platinum cytotoxic drugs, and for monitoring occupational exposure to these drugs and other platinum compounds. The method involves dry ashing of blood samples in a muffle furnace and determination of platinum by adsorptive voltammetric (AV) measurement of the catalytic reduction of protons by the platinum-formazone complex. The detection limit for a 100-microL sample of blood is 0.017 micrograms/L, with a recovery of 94% and a relative standard deviation of 7% at a platinum level of 1 microgram/L. By using this method, the natural levels of platinum in human blood were found to be in the range 0.1-2.8 micrograms/L (median = 0.6 micrograms/L). These results were verified by inductively coupled plasma mass spectrometry (ICP-MS) with blood prepared by wet ashing and using gold as an internal standard.     

Statistical analysis of manual segmentations of structures in medical images

The problem of extracting anatomical structures from medical images is both very important and difficult. In this paper we are motivated by a new paradigm in medical image segmentation, termed Citizen Science, which involves a volunteer effort from multiple, possibly non-expert, human participants. These contributors observe 2D images and generate their estimates of anatomical boundaries in the form of planar closed curves. The challenge, of course, is to combine these different estimates in a coherent fashion and to develop an overall estimate of the underlying structure. Treating these curves as random samples, we use statistical shape theory to generate joint inferences and analyze this data generated by the citizen scientists. The specific goals in this analysis are: (1) to find a robust estimate of the representative curve that provides an overall segmentation, (2) to quantify the level of agreement between segmentations, both globally (full contours) and locally (parts of contours), and (3) to automatically detect outliers and help reduce their influence in the estimation. We demonstrate these ideas using a number of artificial examples and real applications in medical imaging, and summarize their potential use in future scenarios.     

Radiation down-regulates replication origin activity throughout the S phase in mammalian cells

An asynchronous culture of mammalian cells responds acutely to ionizing radiation by inhibiting the overall rate of DNA replication by approximately 50% for a period of several hours, presumably to allow time to repair DNA damage. At low and moderate doses, this S phase damage-sensing (SDS) pathway appears to function primarily at the level of individual origins of replication, with only a modest inhibition of chain elongation per se. We have shown previously that the majority of the inhibition observed in an asynchronous culture can be accounted for by late G1cells that were within 2-3 h of entering the S period at the time of irradiation and which then fail to do so. A much smaller effect was observed on the overall rate of replication in cells that had already entered the S phase. This raised the question whether origins of replication that are activated within S phase per se are inhibited in response to ionizing radiation. Here we have used a two-dimensional gel replicon mapping strategy to show that cells with an intact SDS pathway completely down-regulate initiation in both early- and late-firing rDNA origins in human cells. We also show that initiation in mid- or late-firing rDNA origins is not inhibited in cells from patients with ataxia telangiectasia, confirming the suggestion that these individuals lack the SDS pathway.     

Normal lung function in subjects heterozygous for surfactant protein-B deficiency

OBJECTIVE AND IMPORTANCE: We present a case report of a patient with a left frontal brain abscess. Cultures obtained from the abscess at the time of surgery were identified as dental flora known to establish a synergistic relationship in polymicrobial infections. This type of synergistic relationship makes the clearance of an infection more difficult for an intact immune system. A serum immunoglobulin (Ig) Type A deficiency was identified postoperatively. This immunodeficiency may have contributed to the development of the abscess. CLINICAL PRESENTATION: The patient presented with headaches and photophobia. Computed tomography of the head performed with intravenously administered contrast demonstrated a left frontal brain abscess. INTERVENTION: The patient was operated on through a left frontal approach, carefully avoiding the frontal sinus. The abscess was aspirated, and the patient was treated with intravenous antibiotics for several weeks. Postoperatively, the patient did well. There were no signs of enhancement on follow-up computed tomographic scans at 7 and 12 months postoperatively. CONCLUSION: Through a comprehensive immunological workup, an IgA deficiency was identified postoperatively. Although the deficiency of a single type of Ig may be asymptomatic, complications from recurrent or chronic bacterial infections may occur. The deficiency of IgA, combined with a synergistic polymicrobial infection, contributed to the development of an intracranial abscess. A patient presenting with a brain abscess without any predisposing medical history should be evaluated for an underlying immune deficiency.     

Diversity gain from a single-port adaptive antenna using switchedparasitic elements illustrated with a wire and monopole prototype

A new concept in single-port adaptive antennas using parasitic elements with switched terminating impedances is presented including results from a concept prototype. Each parasitic element can be effectively terminated in three impedance values. The antenna concept provides multiple radiation patterns with a single RF signal port without the need for RF switches or phase shifters in the direct RF signal path. Impedance variations in the active antenna element are minimized by use of only rotationally symmetric configurations. Measured patterns are used to demonstrate the performance improvement expected using switched diversity combining in a simulated uniform scattering scenario. The concept prototype having one active element and four parasitic elements, is shown to have equivalent diversity performance to between three and four uncorrelated branches     

Close friendships among senior adults.

The purpose of this research was to evaluate the relative contributions of personal, affective, and social exchange characteristics to satisfaction with the best friendship. Senior adults (N?=?76) described and evaluated their best friendships in terms of positive and negative affect, equity, reciprocity of social support, and satisfaction. The individual's endorsement of communal and exchange orientations were included as personal characteristics. The study confirms that a communal orientation enhances satisfaction with a best friendship and that conflict and negativity detract from it. Social exchange characteristics were not related to friendship satisfaction. The need to reevaluate the role of social exchange in close relationships is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)