University of Toronto

About: University of Toronto is a education organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 126067 authors who have published 294940 publications receiving 13536856 citations. The organization is also known as: UToronto & U of T.

Lymphoproliferative Disorders with Early Lethality in Mice Deficient in Ctla-4

Abstract: The role of the cell-surface molecule CTLA-4 in the regulation of T cell activation has been controversial. Here, lymph nodes and spleens of CTLA-4-deficient mice accumulated T cell blasts with up-regulated activation markers. These blast cells also infiltrated liver, heart, lung, and pancreas tissue, and amounts of serum immunoglobulin were elevated. The mice invariably became moribund by 3 to 4 weeks of age. Although CTLA-4-deficient T cells proliferated spontaneously and strongly when stimulated through the T cell receptor, they were sensitive to cell death induced by cross-linking of the Fas receptor and by gamma irradiation. Thus, CTLA-4 acts as a negative regulator of T cell activation and is vital for the control of lymphocyte homeostasis.

Don't go it alone: alliance network composition and startups' performance in Canadian biotechnology

Abstract: We combine theory and research on alliance networks and on new firms to investigate the impact of variation in startups’ alliance network composition on their early performance. We hypothesize that startups can enhance their early performance by 1) establishing alliances, 2) configuring them into an efficient network that provides access to diverse information and capabilities with minimum costs of redundancy, conflict, and complexity, and 3) judiciously allying with potential rivals that provide more opportunity for learning and less risk of intra-alliance rivalry. An analysis of Canadian biotech startups’ performance provides broad support for our hypotheses, especially as they relate to innovative performance. Overall, our findings show how variation in the alliance networks startups configure at the time of their founding produces significant differences in their early performance, contributing directly to an explanation of how and why firm age and size affect firm performance. We discuss some clear, but challenging, implications for managers of startups. Copyright © 2000 John Wiley & Sons, Ltd.

Role of the Flt-1 receptor tyrosine kinase in regulating the assembly of vascular endothelium

Abstract: The vascular endothelial growth factor (VEGF) and its high-affinity binding receptors, the tyrosine kinases Flt-1 and Flk-1, are thought to be important for the development of embryonic vasculature. Here we report that Flt-1 is essential for the organization of embryonic vasculature, but is not essential for endothelial cell differentiation. Mouse embryos homozygous for a targeted mutation in the flt-1 locus, flt-1lcz, formed endothelial cells in both embryonic and extra-embryonic regions, but assembled these cells into abnormal vascular channels and died in utero at mid-somite stages. At earlier stages, the blood islands of flt-1lcz homozygotes were abnormal, with angioblasts in the interior as well as on the periphery. We suggest that the Flt-1 signalling pathway may regulate normal endothelial cell-cell or cell-matrix interactions during vascular development.

Autonomous Demand-Side Management Based on Game-Theoretic Energy Consumption Scheduling for the Future Smart Grid

Abstract: Most of the existing demand-side management programs focus primarily on the interactions between a utility company and its customers/users. In this paper, we present an autonomous and distributed demand-side energy management system among users that takes advantage of a two-way digital communication infrastructure which is envisioned in the future smart grid. We use game theory and formulate an energy consumption scheduling game, where the players are the users and their strategies are the daily schedules of their household appliances and loads. It is assumed that the utility company can adopt adequate pricing tariffs that differentiate the energy usage in time and level. We show that for a common scenario, with a single utility company serving multiple customers, the global optimal performance in terms of minimizing the energy costs is achieved at the Nash equilibrium of the formulated energy consumption scheduling game. The proposed distributed demand-side energy management strategy requires each user to simply apply its best response strategy to the current total load and tariffs in the power distribution system. The users can maintain privacy and do not need to reveal the details on their energy consumption schedules to other users. We also show that users will have the incentives to participate in the energy consumption scheduling game and subscribing to such services. Simulation results confirm that the proposed approach can reduce the peak-to-average ratio of the total energy demand, the total energy costs, as well as each user's individual daily electricity charges.

International Study of the Prevalence and Outcomes of Infection in Intensive Care Units

Abstract: Context Infection is a major cause of morbidity and mortality in intensive care units (ICUs) worldwide. However, relatively little information is available about the global epidemiology of such infections. Objective To provide an up-to-date, international picture of the extent and patterns of infection in ICUs. Design, Setting, and Patients The Extended Prevalence of Infection in Intensive Care (EPIC II) study, a 1-day, prospective, point prevalence study with follow-up conducted on May 8, 2007. Demographic, physiological, bacteriological, therapeutic, and outcome data were collected for 14 414 patients in 1265 participating ICUs from 75 countries on the study day. Analyses focused on the data from the 13 796 adult (>18 years) patients. Results On the day of the study, 7087 of 13 796 patients (51%) were considered infected; 9084 (71%) were receiving antibiotics. The infection was of respiratory origin in 4503 (64%), and microbiological culture results were positive in 4947 (70%) of the infected patients; 62% of the positive isolates were gram-negative organisms, 47% were gram-positive, and 19% were fungi. Patients who had longer ICU stays prior to the study day had higher rates of infection, especially infections due to resistant staphylococci, Acinetobacter, Pseudomonas species, and Candida species. The ICU mortality rate of infected patients was more than twice that of noninfected patients (25% [1688/6659] vs 11% [ 682/6352], respectively; P Conclusions Infections are common in patients in contemporary ICUs, and risk of infection increases with duration of ICU stay. In this large cohort, infection was independently associated with an increased risk of hospital death.