Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

Humidity control in houses - ERV technology

Peer reviewed: NoNRC publication: Ye

NRC-IRC researchers study thermal comfort with help of 3-D robot

Aussi disponible en fran\ue7ais: Des cheercheurs de l'IRC \ue9tudient le confort thermique gr\ue2ce \ue0 un robot 3DPeer reviewed: NoNRC publication: Ye

Impact of energy recovery technology on housing performance

Peer reviewed: NoNRC publication: Ye

Forced convective heat transfer of refrigerant 22 evaporating in upward and downward flow in U-bends

Peer reviewed: YesNRC publication: Ye

Stratified air ventilation

This article reviews results of recent NRC-IRC research on the possible use of stratified ventilation systems in cold-climate regions where winter heating is required.Cet article pr\ue9sente les r\ue9sultats des r\ue9centes recherches de l?IRC-CNRC sur l?utilisation potentielle des syst\ue8mes de ventilation stratifi\ue9e dans les r\ue9gions \ue0 climat froid, o\uf9 le chauffage hivernal est imp\ue9ratif.Aussi disponible en fran\ue7ais: La ventilation stratifi\ue9ePeer reviewed: YesNRC publication: Ye

La ventilation stratifi\ue9e

This article reviews results of recent NRC-IRC research on the possible use of stratified ventilation systems in cold-climate regions where winter heating is required.Cet article pr\ue9sente les r\ue9sultats des r\ue9centes recherches de l?IRC-CNRC sur l?utilisation potentielle des syst\ue8mes de ventilation stratifi\ue9e dans les r\ue9gions \ue0 climat froid, o\uf9 le chauffage hivernal est imp\ue9ratif.Also available in English: Stratified Air VentilationPeer reviewed: YesNRC publication: Ye

Hybrid ventilation research for houses

Buildings represent 30% of total energy consumption in Canada. In thermally well-insulated buildings, ventilation and air-conditioning may account for more than 50% of the energy consumption. Improvements in the energy efficiency of ventilating buildings can therefore make a real impact toward reducing Canada's overall energy consumption and GHG emissions.Les b\ue2timents repr\ue9sentent 30 % de la consommation d'\ue9nergie totale au Canada. La ventilation et la climatisation peuvent repr\ue9senter plus de 50 % de la consommation d'\ue9nergie des b\ue2timents dont l'isolation thermique est ad\ue9quate. Or, les am\ue9liorations apport\ue9es \ue0 l'efficacit\ue9 \ue9nerg\ue9tique de la ventilation des b\ue2timents peuvent contribuer de fa\ue7on appr\ue9ciable \ue0 r\ue9duire la consommation d'\ue9nergie totale et les \ue9missions de gaz \ue0 effet de serre \ue0 l'\ue9chelle du pays.Peer reviewed: NoNRC publication: Ye

L?utilisation d?\ue9vents et de conduits d?\ue9vacuation en ventilation naturelle

The research is important because ventilation and air-conditioning can account for up to 50% of residential energy consumption, while having a direct impact on occupant health and comfort. Natural ventilation may result in too little or too much fresh air exchange, and may waste energy in heating or cooling a space. Mechanical ventilation is easily controlled and enables heat recovery and filtration but it consumes electrical energy and thereby promotes greenhouse gas emissions. Hybrid ventilation, combining the advantages of both natural and mechanical ventilation, may offer a way to reduce the energy used for building ventilation.L?\ue9tude sur la ventilation mixte de l?IRC-CNRC est d?autant plus importante que la ventilation et la climatisation repr\ue9sentent jusqu?\ue0 50 % de la consommation \ue9nerg\ue9tique d?une habitation et qu?elles ont un impact direct sur la sant\ue9 et le confort des occupants. La ventilation naturelle a pour inconv\ue9nients ses \ue9changes d?air frais excessifs ou insuffisants, lesquels entra\ueenent irr\ue9m\ue9diablement des d\ue9perditions d?\ue9nergie de chauffage ou de refroidissement. Plus facile \ue0 contr\uf4ler, la ventilation m\ue9canique permet de r\ue9cup\ue9rer la chaleur et de filtrer l?air, mais elle pr\ue9sente l?inconv\ue9nient de fonctionner \ue0 l?\ue9lectricit\ue9 et de contribuer ainsi aux \ue9missions de gaz \ue0 effet de serre. Dans ce contexte, la ventilation mixte, qui associe les avantages de la ventilation m\ue9canique et de la ventilation naturelle, appara\ueet comme une solution susceptible de r\ue9duire l?\ue9nergie utilis\ue9e pour ventiler les b\ue2timents.Also available in English: Use of vents and stacks for natural ventilationPeer reviewed: NoNRC publication: Ye

Simulation of a desiccant-evaporative cooling system for residential buildings

One technology that can help reduce the electricity consumption of conventional air-conditioning technology is the coupling of active dehumidification with evaporative cooling. In this case sensible cooling and moisture removal from indoor and outside ventilation air are decoupled. In this study simulation models are developed for a conventional vapor compression based cooling system and a desiccant evaporative cooling system installed in an R-2000 house. Electricity consumption and comfort indices are then predicted for the two systems for three regions of the country with varying sensible heat ratios. It is found that, compared to a conventional system, the desiccant evaporative cooling system can lead to significant electricity consumption reductions and also reduce the number of hours when conditions inside the space are uncomfortable.Le couplage de la d\ue9shumidification active au principe du refroidissement par \ue9vaporation repr\ue9sente une technologie qui peut aider \ue0 r\ue9duire la consommation d'\ue9lectricit\ue9 de la technologie traditionnelle \ue0 base de refroidissement de l'air. Dans ce cas-ci, la puissance frigorifique sensible et l'enl\ue8vement de l'humidit\ue9 de l'air de ventilation int\ue9rieur et ext\ue9rieur se trouvent d\ue9coupl\ue9s. Dans le cadre de cette \ue9tude, des mod\ue8les de simulation sont d\ue9velopp\ue9s pour un syst\ue8me de refroidissement \ue0 compression de vapeur du type traditionnel et un syst\ue8me de refroidissement \ue0 \ue9vaporation par d\ue9shydratant, install\ue9s dans une maison R-2000. La consommation d'\ue9lectricit\ue9 et les indices de confort sont ensuite pr\ue9dits pour les deux syst\ue8mes, pour trois (3) r\ue9gions canadiennes diff\ue9rentes avec divers coefficients de chaleur sensible. Il s'est av\ue9r\ue9 que compar\ue9 \ue0 un syst\ue8me traditionnel, le syst\ue8me de refroidissement \ue0 \ue9vaporation par d\ue9shydratant peut entra\ueener des r\ue9ductions consid\ue9rables dans la consommation et en outre r\ue9duire le nombre d'heures d'inconfort \ue0 l'int\ue9rieur des habitations.Peer reviewed: YesNRC publication: Ye