Proceedings of the Natural Academy of Sciences

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mCHH islands in maize [Plant Biology]

Tue, 11/24/2015 - 13:04
The maize genome is relatively large (∼2.3 Gb) and has a complex organization of interspersed genes and transposable elements, which necessitates frequent boundaries between different types of chromatin. The examination of maize genes and conserved noncoding sequences revealed that many of these are flanked by regions of elevated asymmetric CHH...
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QQS modulates carbon partitioning across species [Plant Biology]

Tue, 11/24/2015 - 13:04
The allocation of carbon and nitrogen resources to the synthesis of plant proteins, carbohydrates, and lipids is complex and under the control of many genes; much remains to be understood about this process. QQS (Qua-Quine Starch; At3g30720), an orphan gene unique to Arabidopsis thaliana, regulates metabolic processes affecting carbon and...
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Emotions track changes in the acoustic environment [Psychological and Cognitive Sciences]

Tue, 11/24/2015 - 13:04
Emotional responses to biologically significant events are essential for human survival. Do human emotions lawfully track changes in the acoustic environment? Here we report that changes in acoustic attributes that are well known to interact with human emotions in speech and music also trigger systematic emotional responses when they occur...
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In This Issue [This Week in PNAS]

Tue, 11/24/2015 - 13:04
Birth of babies through round spermatid injection Baby born through ROSI. Men incapable of producing mature spermatozoa are often pronounced sterile and advised to consider donor sperm. Though round spermatids, which are 6–8 μm spheres that appear early in sperm development and give rise to mature sperm, have been used...
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Policy challenges for the Anthropocene [Sustainability Science]

Tue, 11/24/2015 - 13:04
Developing effective governance structures for the fair and sustainable use of benefits that flow from shared natural resources is arguably one of the defining challenges of our time. Addressing this challenge has been extremely difficult because the associated governance problem is multifaceted and multilayered. Governance structures must address at least...
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DNA domain formation via CTCF-mediated extrusion [Biophysics and Computational Biology]

Tue, 11/24/2015 - 13:04
The extraordinary compaction of DNA in vivo, 2 m of DNA packed into a nucleus that is six orders of magnitude smaller, presents a conundrum: How can the cell maintain this highly dense chromatin structure while also carrying out exquisitely regulated processes like gene expression, DNA replication, and DNA repair?...
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Neuroendocrine stem-like prostate tumors [Medical Sciences]

Tue, 11/24/2015 - 13:04
Metastatic prostate cancer (PCa) requires immediate attention in order to identify driving molecular mechanisms and therapeutic targets that will achieve sustainable regression of disease. Despite advances with novel therapies, patients either do not respond or develop rapid resistance to these agents (1). An emerging resistant phenotype is small-cell neuroendocrine prostate...
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Imprinted X inactivation and hemizygosity converge [Genetics]

Tue, 11/24/2015 - 13:04
The first disparity between the sexes occurs upon fertilization: the sex chromosome complement is asymmetric in mammals, with females bearing two Xs and males bearing one X and one Y. Because of this, evolutionary forces have selected for one of the most fascinating epigenetic events in chromosome biology—the process of...
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Penciling in details of the Hadean [Earth, Atmospheric, and Planetary Sciences]

Tue, 11/24/2015 - 13:04
Some truly remarkable graphite is described by Bell et al. in PNAS (1). Graphite is, of course, the same material as found in pencil tips or in the anode of lithium ion batteries. Graphite is, however, also a very common material in Earth Science, and is often the form of...
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The engineering of biology and medicine [Introductions]

Tue, 11/24/2015 - 13:04
In celebration of the 100th Anniversary of PNAS, this Special Feature summarizes the enormous progress that has been made in the engineering of biology and medicine. In 1915, PNAS published articles, such as “A comparison of methods for determining the respiratory exchange of man,” by T. M. Carpenter (1), “The...
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Advancing biomedical imaging [Biological Sciences]

Tue, 11/24/2015 - 13:04
Imaging reveals complex structures and dynamic interactive processes, located deep inside the body, that are otherwise difficult to decipher. Numerous imaging modalities harness every last inch of the energy spectrum. Clinical modalities include magnetic resonance imaging (MRI), X-ray computed tomography (CT), ultrasound, and light-based methods [endoscopy and optical coherence tomography...
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Synthetic biology diagnostics [Biological Sciences]

Tue, 11/24/2015 - 13:04
There is a growing need to enhance our capabilities in medical and environmental diagnostics. Synthetic biologists have begun to focus their biomolecular engineering approaches toward this goal, offering promising results that could lead to the development of new classes of inexpensive, rapidly deployable diagnostics. Many conventional diagnostics rely on antibody-based...
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Nanotechnologies for biomedicine [Biological Sciences]

Tue, 11/24/2015 - 13:04
In 2000 the United States launched the National Nanotechnology Initiative and, along with it, a well-defined set of goals for nanomedicine. This Perspective looks back at the progress made toward those goals, within the context of the changing landscape in biomedicine that has occurred over the past 15 years, and...
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Progress in biomaterial design [Physical Sciences]

Tue, 11/24/2015 - 13:04
Biomaterials that interface with biological systems are used to deliver drugs safely and efficiently; to prevent, detect, and treat disease; to assist the body as it heals; and to engineer functional tissues outside of the body for organ replacement. The field has evolved beyond selecting materials that were originally designed...
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Progress in regenerative medicine [Biological Sciences]

Tue, 11/24/2015 - 13:04
Organ and tissue loss through disease and injury motivate the development of therapies that can regenerate tissues and decrease reliance on transplantations. Regenerative medicine, an interdisciplinary field that applies engineering and life science principles to promote regeneration, can potentially restore diseased and injured tissues and whole organs. Since the inception...
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Smart nanosystems: Host-responsive technologies [Physical Sciences]

Tue, 11/24/2015 - 13:04
Nanoparticle technologies intended for human administration must be designed to interact with, and ideally leverage, a living host environment. Here, we describe smart nanosystems classified in two categories: (i) those that sense the host environment and respond and (ii) those that first prime the host environment to interact with engineered...
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Engineering opportunities in cancer immunotherapy [Biological Sciences]

Tue, 11/24/2015 - 13:04
Immunotherapy has great potential to treat cancer and prevent future relapse by activating the immune system to recognize and kill cancer cells. A variety of strategies are continuing to evolve in the laboratory and in the clinic, including therapeutic noncellular (vector-based or subunit) cancer vaccines, dendritic cell vaccines, engineered T...
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Accurate influenza epidemics estimation via ARGO [Applied Mathematics]

Tue, 11/24/2015 - 13:04
Accurate real-time tracking of influenza outbreaks helps public health officials make timely and meaningful decisions that could save lives. We propose an influenza tracking model, ARGO (AutoRegression with GOogle search data), that uses publicly available online search data. In addition to having a rigorous statistical foundation, ARGO outperforms all previously...
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Mapping transient E fields with ps electrons [Applied Physical Sciences]

Tue, 11/24/2015 - 13:04
Transient electric fields, which are an important but hardly explored parameter of laser plasmas, can now be diagnosed experimentally with combined ultrafast temporal resolution and field sensitivity, using femtosecond to picosecond electron or proton pulses as probes. However, poor spatial resolution poses great challenges to simultaneously recording both the global...
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Self-assembly of smallest magnetic nanoparticles [Applied Physical Sciences]

Tue, 11/24/2015 - 13:04
The assembly of tiny magnetic particles in external magnetic fields is important for many applications ranging from data storage to medical technologies. The development of ever smaller magnetic structures is restricted by a size limit, where the particles are just barely magnetic. For such particles we report the discovery of...
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