Metabolic Teamwork in the Stem Cell Niche

Nearby cells can support stem cell differentiation, but the metabolic activities in stem cell niches are unknown. A recent study (Rodríguez-Colman et al., 2017) reveals a metabolic partnership in the intestinal stem cell niche: glycolysis in niche Paneth cells provides lactate to drive mitochondrial oxidative phosphorylation in intestinal stem cells

Molecular Pathways: Dietary Regulation of Stemness and Tumor Initiation by the PPAR- Pathway

Peroxisome proliferator-activated receptor delta (PPAR-8) is a nuclear receptor transcription factor that regulates gene expression during development and disease states, such as cancer. However, the precise role of PPAR-8 during tumorigenesis is not well understood. Recent data suggest that PPAR-8 may have context-specific oncogenic and tumor-suppressive roles depending on the tissue, cell-type, or diet-induced physiology in question. For example, in the intestine, pro-obesity diets, such as a high-fat diet (HFD), are associated with increased colorectal cancer incidence. Interestingly, many of the effects of an HFD in the stem and progenitor cell compartment are driven by a robust PPAR-8 program and contribute to the early steps of intestinal tumorigenesis. Importantly, the PPAR-8 pathway or its downstream mediators may serve as therapeutic intervention points or biomarkers in colon cancer that arise in patients who are obese. Although potent PPAR-8 agonists and antagonists exist, their clinical utility may be enhanced by uncovering how PPAR-8 mediates tumorigenesis in diverse tissues and cell types as well as in response to diet.National Institutes of Health (U.S.) (Grant R00-AG045144

A highly resilient and zone-based key predistribution protocol for multiphase wireless sensor networks

Pairwise key distribution among the sensor nodes is an essential problem for providing security in Wireless Sensor Networks (WSNs). The common approach for this problem is random key predistribution, which suffers from resiliency issues in case of node captures by adversaries. In the literature, the resiliency problem is addressed by zone-based deployment models that use prior deployment knowledge. Another remedy in the literature, which is for multiphase WSNs, aims to provide self-healing property via periodic deployments of sensor nodes with fresh keys over the sensor field. However, to the best of our knowledge, these two approaches have never been combined before in the literature. In this paper, we propose a zone-based key predistribution approach for multiphase WSNs. Our approach combines the best parts of these approaches and provides self-healing property with up to 9-fold more resiliency as compared to an existing scheme. Moreover, our scheme ensures almost 100% secure connectivity, which means a sensor node shares at least one key with almost all of its neighbors

Multiphase deployment models for fast self healing in wireless sensor networks

The majority of studies on security in resource limited wireless sensor networks (WSN) focus on finding an efficient balance among energy consumption, computational speed and memory usage. Besides these resources, time is a relatively immature aspect that can be considered in system design and performance evaluations. In a recent study(Castelluccia and Spognardi, 2007), the time dimension is used to lower the ratio of compromised links, thus, improving resiliency in key distribution in WSNs. This is achieved by making the old and possibly compromised keys useful only for a limited amount of time. In this way, the effect of compromised keys diminish in time, so the WSN selfheals. In this study we further manipulate the time dimension and propose a deployment model that speeds up the resilience improvement process with a tradeoff between connectivity and resiliency. In our method, self healing speeds up by introducing nodes that belong to future generations in the time scale. In this way, the duration that the adversary can make use of compromised keys become smaller

A Critical Review for the Possibility of Science without ‘Eppue Si Muove’: From Thomas Kuhn’s Theory of Science to Psychology of Science

The theory of science that Thomas Kuhn built in the Structure of Scientific Revolutions was considered as a hypothetical framework in this study. Since the publication of the work, many questions have arisen that call for a psychology of science. These questions are moved to another dimension through the knowledge of the decision made within Galileo Affair, which occupies an important place in modern science, fundamentally arising from an epistemic struggle and emerging out of an unscientific base rather than the charge of unholiness. Abandoning the perspective which evaluates these questions within a historical process as a weak side of the Kuhnian theory of science, this study challenges the current approaches with an alternative approach. The epistemic complexity in the Kuhnian theory of science is an imperative complexity caused by human factors. From this perspective, there are potential questions for psychology of science as a field of study based on Kuhnian epistemology and it can be assumed that new problems may appear when the other epistemological questions which assumed as “answered” are reviewed in the scope of this study. The main thesis of this study is that psychology of science is possible as a valid and operationalizable research program based on Kuhnian theory of science

Use of religion in blame avoidance in a competitive authoritarian regime

Blame avoidance has been one of the most applied strategies by policy makers in both democratic and non-democratic regimes to avoid responsibility and accountability in cases of failure and tragic events. It is also known that politicians have used religion for Machiavellian purposes, as exactly advised by Machiavelli. However, a systematic empirical analysis of how religion is used for blame avoidance by politicians has not been conducted. In this article, we aim to address this gap by examining the empirical data derived from the weekly Friday sermon texts produced by Turkey’s Directorate of Religious Affairs and delivered in more than 90 thousand mosques every week to a large segment of the population in Turkey, where the majority claims to be religious. Starting with its violent response to the peaceful Gezi protests in 2013, the ruling AKP has opened up a new phase in Turkish political history by resorting to civilizational populism: it blamed the Western world for financing and masterminding the protests, using the protestors as internal pawns to attack Turkey and the Muslim World, suppressed the protests brutally and entered into a populist authoritarian regime. Our paper shows, following this turn, how the Diyanet sermons started using religion to help with the AKP’s blame avoidance. The Diyanet either parroted the AKP’s conspiratorial narrative or tried to convince the citizens that all negativities are works of God and with these humans are being tested by God. The AKP’s use of religion to avoid blame is a text-book case of how both a religious institution and religious discourse can be used to help the incumbent avoid responsibility. Whenever, there was a problem that would the AKP votes, the Diyanet’s sermons tried to shift the blame to either God or citizens or conspiratorial enemies