Cancer stem cells (CSCs) are a class of pluripotent cells that have been observed in most types of solid and hematologic cancers. CSCs have been shown in numerous cancer models to be involved in ...tumor development, cell proliferation, and metastatic dissemination, while possessing a capacity for sustained self-renewal. CSCs, which typically represent a small proportion of total cells of a given tumor, also exhibit resistance to chemotherapy and radiotherapy. Indeed, exposure to these treatments may promote "stemness" in nonstem cancer cells, which may explain why successful therapeutic reduction of tumor bulk will often fail to produce clinical improvement. Acquisition of stemness involves epithelial-mesenchymal transition (EMT), in which epithelial cells are transformed into a mesenchymal phenotype characterized by increased capacities for migration, invasiveness, and resistance to apoptosis. EMT may also contribute to metastasis by driving dissemination of mesenchymal CSCs to distant locations, whereupon the CSCs revert to an epithelial phenotype to support metastatic tumor growth. Several different approaches to treatment aimed at overcoming the intrinsic resistance of CSCs to conventional therapies are currently being developed. These include agents targeting tumorigenic pathways, such as JAK2/STAT3 and PI3K/mTOR, and immunotherapies, including vaccines and natural killer cells employed to induce a T cell response.
Men and women exhibit significant differences in obesity, cardiovascular disease, and diabetes. To provide better diagnosis and treatment for both sexes, it is important to identify factors that ...underlie the observed sex differences. Traditionally, sex differences have been attributed to the differential effects of male and female gonadal secretions (commonly referred to as sex hormones), which substantially influence many aspects of metabolism and related diseases. Less appreciated as a contributor to sex differences are the fundamental genetic differences between males and females, which are ultimately determined by the presence of an XX or XY sex chromosome complement. Here, we review the mechanisms by which gonadal hormones and sex chromosome complement each contribute to lipid metabolism and associated diseases, and the current approaches that are used to study them. We focus particularly on genetic approaches including genome-wide association studies in humans and mice, -omics and systems genetics approaches, and unique experimental mouse models that allow distinction between gonadal and sex chromosome effects.
Agriculture can serve as an important engine for economic growth in developing countries, yet yields in these countries have lagged far behind those in developed countries for decades. One potential ...mechanism for increasing yields is the use of improved agricultural technologies, such as fertilizers, seeds, and cropping techniques. Public sector programs have attempted to overcome information‐related barriers to technological adoption by providing agricultural extension services. While such programs have been widely criticized for their limited scale, sustainability, and impact, the rapid spread of mobile phone coverage in developing countries provides a unique opportunity to facilitate technological adoption via information and communication technology (ICT)‐based extension programs. This article outlines the potential mechanisms through which ICT could facilitate agricultural adoption and the provision of extension services in developing countries. It then reviews existing programs using ICT for agriculture, categorized by the mechanism (voice, text, internet, and mobile money transfers) and the type of services provided. Finally, we identify potential constraints to such programs in terms of design and implementation, and conclude with some recommendations for implementing field‐based research on the impact of these programs on farmers’ knowledge, technological adoption, and welfare.
We conducted a systematic literature review to summarize the current health economic evidence for whole-exome sequencing (WES) and whole-genome sequencing (WGS).
Relevant studies were identified in ...the EMBASE, MEDLINE, Cochrane Library, EconLit and University of York Centre for Reviews and Dissemination databases from January 2005 to July 2016. Publications were included in the review if they were economic evaluations, cost studies, or outcome studies.
Thirty-six studies met our inclusion criteria. These publications investigated the use of WES and WGS in a variety of genetic conditions in clinical practice, the most common being neurological or neurodevelopmental disorders. Study sample size varied from a single child to 2,000 patients. Cost estimates for a single test ranged from $555 to $5,169 for WES and from $1,906 to $24,810 for WGS. Few cost analyses presented data transparently and many publications did not state which components were included in cost estimates.
The current health economic evidence base to support the more widespread use of WES and WGS in clinical practice is very limited. Studies that carefully evaluate the costs, effectiveness, and cost-effectiveness of these tests are urgently needed to support their translation into clinical practice.
Access to and use of mobile telephony in sub-Saharan Africa has increased dramatically over the past decade. Mobile telephony has brought new possibilities to the continent. Across urban–rural and ...rich–poor divides, mobile phones connect individuals to individuals, information, markets, and services. These effects can be particularly dramatic in rural Africa, where in many places mobile phones have represented the first modern telecommunications infrastructure of any kind. Mobile phones have greatly reduced communication costs, thereby allowing individuals and firms to send and to obtain information quickly and cheaply on a variety of economic, social, and political topics. An emerging body of research shows that the reduction in communication costs associated with mobile phones has tangible economic benefits, improving agricultural and labor market efficiency and producer and consumer welfare in specific circumstances and countries. This paper first examines the evolution of mobile phone coverage and adoption in sub-Saharan Africa over the past decade. We then explore the main channels through which mobile phones can effect economic outcomes and appraise current evidence of its potential to improve economic development. We conclude with directions for future research and outline the necessary conditions for mobile phones to promote broader economic development in Africa.
Stereopsis is the computation of depth information from views acquired simultaneously from different points in space. For many years, stereopsis was thought to be confined to primates and other ...mammals with front-facing eyes. However, stereopsis has now been demonstrated in many other animals, including lateral-eyed prey mammals, birds, amphibians and invertebrates. The diversity of animals known to have stereo vision allows us to begin to investigate ideas about its evolution and the underlying selective pressures in different animals. It also further prompts the question of whether all animals have evolved essentially the same algorithms to implement stereopsis. If so, this must be the best way to do stereo vision, and should be implemented by engineers in machine stereopsis. Conversely, if animals have evolved a range of stereo algorithms in response to different pressures, that could inspire novel forms of machine stereopsis appropriate for distinct environments, tasks or constraints. As a first step towards addressing these ideas, we here review our current knowledge of stereo vision in animals, with a view towards outlining common principles about the evolution, function and mechanisms of stereo vision across the animal kingdom. We conclude by outlining avenues for future work, including research into possible new mechanisms of stereo vision, with implications for machine vision and the role of stereopsis in the evolution of camouflage.
Price dispersion across markets is common in developing countries. Using novel market and trader-level data, this paper provides estimates of the impact of mobile phones on price dispersion across ...grain markets in Niger. The introduction of mobile phone service between 2001 and 2006 explains a 10 to 16 percent reduction in grain price dispersion. The effect is stronger for market pairs with higher transport costs.
A revealing look at how the Orpheus myth helped
Renaissance writers and thinkers understand the force of
eloquence In ancient Greek mythology, the lyrical songs of
Orpheus charmed the gods, and ...compelled animals, rocks, and trees
to obey his commands. This mythic power inspired Renaissance
philosophers and poets as they attempted to discover the hidden
powers of verbal eloquence. They wanted to know: How do words
produce action? In The Trials of Orpheus , Jenny Mann
examines the key role the Orpheus story played in helping early
modern writers and thinkers understand the mechanisms of rhetorical
force. Mann demonstrates that the forms and figures of ancient
poetry indelibly shaped the principles of sixteenth- and
seventeenth-century scientific knowledge. Mann explores how Ovid's
version of the Orpheus myth gave English poets and natural
philosophers the lexicon with which to explain language's ability
to move individuals without physical contact. These writers and
thinkers came to see eloquence as an aesthetic force capable of
binding, drawing, softening, and scattering audiences. Bringing
together a range of examples from drama, poetry, and philosophy by
Bacon, Lodge, Marlowe, Montaigne, Shakespeare, and others, Mann
demonstrates that the fascination with Orpheus produced some of the
most canonical literature of the age. Delving into the impact of
ancient Greek thought and poetry in the early modern era, The
Trials of Orpheus sheds light on how the powers of rhetoric
became a focus of English thought and literature.
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