Decoding Information from noisy, redundant, and intentionally-distorted sources

Advances in information technology reduce barriers to information propagation, but at the same time they also induce the information overload problem. For the making of various decisions, mere digestion of the relevant information has become a daunting task due to the massive amount of information available. This information, such as that generated by evaluation systems developed by various web sites, is in general useful but may be noisy and may also contain biased entries. In this study, we establish a framework to systematically tackle the challenging problem of information decoding in the presence of massive and redundant data. When applied to a voting system, our method simultaneously ranks the raters and the ratees using only the evaluation data, consisting of an array of scores each of which represents the rating of a ratee by a rater. Not only is our appraoch effective in decoding information, it is also shown to be robust against various hypothetical types of noise as well as intentional abuses.Comment: 19 pages, 5 figures, accepted for publication in Physica

Sulindac Enhances the Killing of Cancer Cells Exposed to Oxidative Stress

BACKGROUND:Sulindac is an FDA-approved non-steroidal anti-inflammatory drug (NSAID) that affects prostaglandin production by inhibiting cyclooxygenases (COX) 1 and 2. Sulindac has also been of interest for more than decade as a chemopreventive for adenomatous colorectal polyps and colon cancer. PRINCIPAL FINDINGS:Pretreatment of human colon and lung cancer cells with sulindac enhances killing by an oxidizing agent such as tert-butyl hydroperoxide (TBHP) or hydrogen peroxide. This effect does not involve cyclooxygenase (COX) inhibition. However, under the conditions used, there is a significant increase in reactive oxygen species (ROS) within the cancer cells and a loss of mitochondrial membrane potential, suggesting that cell death is due to apoptosis, which was confirmed by Tunel assay. In contrast, this enhanced killing was not observed with normal lung or colon cells. SIGNIFICANCE:These results indicate that normal and cancer cells handle oxidative stress in different ways and sulindac can enhance this difference. The combination of sulindac and an oxidizing agent could have therapeutic value

Infection of Human Neural Cell Aggregate Cultures with a Clinical Isolate of Cytomegalovirus

Human neural cell aggregate cultures were prepared from dissociated fetal brain tissue and maintained in rotation culture. After 35 days in culture, aggregates had the histologic appearance of dense, immature, neural cells in a tightly packed neuropil. Electron microscopy revealed ultrastructural features suggestive of immature neurons and neuroglia. In addition, neuron-specific enolase and glial fibrillary acidic protein associated with radial glial cells were detected within the aggregates by immunoperoxidase staining. When infected with a laboratory-adapted strain of cytomegalovirus (CMV), [AD169], cells containing large, bizarre, nuclei and CMV-induced intranuclear inclusion bodies were dispersed throughout the aggregates at 16 days postinfection. In situ hybridization using a CMV-specific DNA probe and electron microscopy confirmed the presence of virus sequences as well as virus particles at histologic sites of cytopathology. In sharp contrast, aggregate cultures infected with a CMV strain recovered from the retina of an acquired immune deficiency syndrome (AIDS) patient with CMV retinitis and encephalitis displayed distinct foci of cytopathology at 23 days postinfection, a pattern not observed in CMV [AD169]-infected aggregates. Our findings suggest that human neural cell aggregates represent a promising multicellular non-neoplastic culture system in which to study the replication of human neurotropic viruses within neural tissue

Improving the accuracy of Business-to-Business (B2B) reputation systems through rater expertise prediction

International audienceDigital ecosystems rely on reputation systems in order to build trust and to foster collaborations among users. Reputation systems are commonplace in the C2C and B2C contexts, however, they have not yet found mainstream acceptance in B2B environments. Our first contribution in this paper is to identify the particularities of feedback collection in B2B reputation systems. An issue that we identify is that the reputation target in the B2B context is a business, which requires evaluation on a large number of criteria. We observe that due to the wide variation in user expertise, feedback forms that require users to evaluate all criteria have significant negative consequences for rating accuracy. Our second contribution is to propose an expertise prediction algorithm for B2B reputation systems, which filters the criteria describing the target business such that each user rates only on those criteria that he has expertise in. Experiments based on our real dataset show that the algorithm accurately predicts the expertise of users in given criteria. The algorithm may also increase the motivation of users to submit feedback as well as the confidence of users in B2B reputation systems

Association of ‘(tropical) ataxic neuropathy’ with HTLV-II

Jamaican Neuropathy of the ataxic type (tropical ataxic neuropathy [TAN] and spastic type (tropical spastic paraparesis [TSP]) have been recognized for over a century in Jamaica. The recent association of TSP with HTLV-I (TSP/HAM) is now well established. We now present evidence for a possible association between a TAN-like illness with HTLV-II in four females aged 34–49. All presented with ataxic gait and all four have prominent mental changes. Three of the four also have minor motor deficits with urinary frequency and two have nocturnal leg cramps. All have serum antibody and all had PCR evidence of HTLV-II infection. Antibody to HTLV-II is present in CSF from two subjects. The distinctive picture of prominent ataxia and altered mental status in these subjects contrasts with a predominantly myelopathic picture seen in TSP/HAM

Concentration-targeted phase I trials of atevirdine mesylate in patients with HIV infection: dosage requirements and pharmacokinetic studies

Rationale: To determine the dosage requirements and pharmacokinetics of atevirdine, a non-nucleoside reverse transcriptase inhibitor and its N-dealkylated metabolite (N-ATV) during phase I studies in patients receiving atevirdine alone or in combination with zidovudine. Design: Two open label, phase I studies conducted by the adult AIDS Clinical Trials Group (ACTG) in which atevirdine was administered every 8 h with weekly dosage adjustments to attain targeted trough plasma atevirdine concentrations. Setting: Five Adult AIDS Clinical Trials Units. Patients: Fifty patients (ACTG 199; n=20 and ACTG 187; n=30) with HIV-1 infection and ≤500 CD4+ lymphocytes/mm 3. Intervention: ACTG 199: 12 weeks of therapy with atevirdine (dose-adjusted to achieve plasma trough atevirdine concentrations of 5–10 μM) and zidovudine (200 mg every 8 h). ACTG 187: 12 weeks of atevirdine monotherapy with atevirdine doses adjusted to achieve escalating, targeted trough plasma concentration ranges (5–13, 14–22, and 23–31 μM). Measurements: ACTG 199: atevirdine, N-ATV and zidovudine trough determinations weekly (all patients) and intensive pharmacokinetics (selected patients) prior to and at 6 and 12 weeks during combination therapy. ACTG 187: atevirdine and N-ATV trough concentrations over a 12 week period. Intensive pharmacokinetic studies were conducted prior to and at 4 and/or 8 weeks during atevirdine monotherapy in female patients. Results: Atevirdine plasma concentrations demonstrated considerable interpatient variability which was minimized by the adjustment of maintenance doses (range: 600–3900 mg/day) to achieve the desired trough concentrations. In ACTG 187, the mean number of weeks to attain the target value, and the percentage of patients who attained the target, was group I (5–11 μM): 2.7±2.4 weeks (92%); group II (12–21 μM): 2.6±1.8 (64%); and group III (22–31 μM): 7.0±5.6 weeks (27%). In ACTG 199 it was 3.2±5.2 weeks (95%) to achieve a 5–10 μM trough. Atevirdine demonstrated a mono- or bi-exponential decline among most of the patients studied after the first dose. During multiple-dosing a number of patterns of atevirdine disposition were observed including; rapid absorption with C max at 0.5–1 h, delayed absorption with C max at 3–4 h; minimal C max to C min fluctuation and C max to C min ratios of >4. N-ATV (an inactive metabolite) patterns were characterized on day one by rapid appearance of the metabolite which peaked at 2–3 h after the dose and declined in a mono- or bi-exponential manner. At steady-state N-ATV patterns demonstrated minimal C max to C min fluctuations with some of the patients having more stable plasma N-ATV concentrations, while others had greater fluctuations week to week. Conclusions: Considerable interpatient variability was noted in the pharmacokinetics of atevirdine. The variation in drug disposition was reflected in the range of daily doses required to attain the targeted trough concentrations. Atevirdine metabolism did not appear to reach saturation during chronic dosing in many of our patients, as reflected by the pattern of N-ATV/ATV ratios in plasma and saturation was not an explanation for the variation in dosing requirements. No apparent differences were noted between males and females, and atevirdine did not appear to influence zidovudine disposition