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Updated: 1 year 51 weeks ago

[This Week in Science] Charge separation viewed in reflection

Fri, 11/27/2015 - 00:00
Author: Jake Yeston
Categories: Journal Articles

[This Week in Science] Tweaking T regulatory affairs

Fri, 11/27/2015 - 00:00
Author: Angela Colmone
Categories: Journal Articles

[This Week in Science] Imaging with molecular vibrations

Fri, 11/27/2015 - 00:00
Author: Phil Szuromi
Categories: Journal Articles

[This Week in Science] A census of neocortical neurons

Fri, 11/27/2015 - 00:00
Author: Peter Stern
Categories: Journal Articles

[This Week in Science] Proteins shape up in the ribosome

Fri, 11/27/2015 - 00:00
Author: Guy Riddihough
Categories: Journal Articles

[This Week in Science] The downside of innovation

Fri, 11/27/2015 - 00:00
Author: Sacha Vignieri
Categories: Journal Articles

[This Week in Science] Zeroing in on essential human genes

Fri, 11/27/2015 - 00:00
Author: L. Bryan Ray
Categories: Journal Articles

[This Week in Science] Antidepressants suppress DNA methylation

Fri, 11/27/2015 - 00:00
Author: Leslie K. Ferrarelli
Categories: Journal Articles

[Editors' Choice] More neurons mean less need for sleep

Fri, 11/27/2015 - 00:00
Author: Peter Stern
Categories: Journal Articles

[Editors' Choice] Diversity through ADVANCEment

Fri, 11/27/2015 - 00:00
Author: Melissa McCartney
Categories: Journal Articles

[Editors' Choice] Cell size matters to meristems

Fri, 11/27/2015 - 00:00
Author: Pamela J. Hines
Categories: Journal Articles

[Editors' Choice] A shifting wet girdle around the tropics

Fri, 11/27/2015 - 00:00
Author: H. Jesse Smith
Categories: Journal Articles

[Editors' Choice] Committing to memory

Fri, 11/27/2015 - 00:00
Author: Lisa D. Chong
Categories: Journal Articles

[Editors' Choice] Mitochondrial quality control

Fri, 11/27/2015 - 00:00
Author: Stella M. Hurtley
Categories: Journal Articles

[Editors' Choice] Crystal structure of a rhodium carbene

Fri, 11/27/2015 - 00:00
Author: Jake Yeston
Categories: Journal Articles

[Review] Vibrational spectroscopic imaging of living systems: An emerging platform for biology and medicine

Fri, 11/27/2015 - 00:00
Vibrational spectroscopy has been extensively applied to the study of molecules in gas phase, in condensed phase, and at interfaces. The transition from spectroscopy to spectroscopic imaging of living systems, which allows the spectrum of biomolecules to act as natural contrast, is opening new opportunities to reveal cellular machinery and to enable molecule-based diagnosis. Such a transition, however, involves more than a simple combination of spectrometry and microscopy. We review recent efforts that have pushed the boundary of the vibrational spectroscopic imaging field in terms of spectral acquisition speed, detection sensitivity, spatial resolution, and imaging depth. We further highlight recent applications in functional analysis of single cells and in label-free detection of diseases. Authors: Ji-Xin Cheng, X. Sunney Xie
Categories: Journal Articles

[Research Article] Principles of connectivity among morphologically defined cell types in adult neocortex

Fri, 11/27/2015 - 00:00
Since the work of Ramón y Cajal in the late 19th and early 20th centuries, neuroscientists have speculated that a complete understanding of neuronal cell types and their connections is key to explaining complex brain functions. However, a complete census of the constituent cell types and their wiring diagram in mature neocortex remains elusive. By combining octuple whole-cell recordings with an optimized avidin-biotin-peroxidase staining technique, we carried out a morphological and electrophysiological census of neuronal types in layers 1, 2/3, and 5 of mature neocortex and mapped the connectivity between more than 11,000 pairs of identified neurons. We categorized 15 types of interneurons, and each exhibited a characteristic pattern of connectivity with other interneuron types and pyramidal cells. The essential connectivity structure of the neocortical microcircuit could be captured by only a few connectivity motifs. Authors: Xiaolong Jiang, Shan Shen, Cathryn R. Cadwell, Philipp Berens, Fabian Sinz, Alexander S. Ecker, Saumil Patel, Andreas S. Tolias
Categories: Journal Articles

[Research Article] A continent-wide assessment of the form and intensity of large mammal herbivory in Africa

Fri, 11/27/2015 - 00:00
Megafaunal extinctions and a lack of suitable remote sensing technology impede our understanding of both the ecological legacy and current impacts of large mammal herbivores in the Earth system. To address this, we reconstructed the form and intensity of herbivory pressure across sub-Saharan Africa ~1000 years ago. Specifically, we modeled and mapped species-level biomass for 92 large mammal herbivores using census data, species distributions, and environmental covariates. Trait-based classifications of these species into herbivore functional types, and analyses of their biomass surfaces, reveal four ecologically distinct continental-scale herbivory regimes, characterized by internally similar forms and intensities of herbivory pressure. Associations between herbivory regimes, fire prevalence, soil nutrient status, and rainfall provide important insights into African ecology and pave the way for integrating herbivores into global-scale studies. Authors: Gareth P. Hempson, Sally Archibald, William J. Bond
Categories: Journal Articles

[Report] Semiconductor interfacial carrier dynamics via photoinduced electric fields

Fri, 11/27/2015 - 00:00
Solar photoconversion in semiconductors is driven by charge separation at the interface of the semiconductor and contacting layers. Here we demonstrate that time-resolved photoinduced reflectance from a semiconductor captures interfacial carrier dynamics. We applied this transient photoreflectance method to study charge transfer at p-type gallium-indium phosphide (p-GaInP2) interfaces critically important to solar-driven water splitting. We monitored the formation and decay of transient electric fields that form upon photoexcitation within bare p-GaInP2, p-GaInP2/platinum (Pt), and p-GaInP2/amorphous titania (TiO2) interfaces. The data show that a field at both the p-GaInP2/Pt and p-GaInP2/TiO2 interfaces drives charge separation. Additionally, the charge recombination rate at the p-GaInP2/TiO2 interface is greatly reduced owing to its p-n nature, compared with the Schottky nature of the p-GaInP2/Pt interface. Authors: Ye Yang, Jing Gu, James L. Young, Elisa M. Miller, John A. Turner, Nathan R. Neale, Matthew C. Beard
Categories: Journal Articles

[Report] Near-unity photoluminescence quantum yield in MoS2

Fri, 11/27/2015 - 00:00
Two-dimensional (2D) transition metal dichalcogenides have emerged as a promising material system for optoelectronic applications, but their primary figure of merit, the room-temperature photoluminescence quantum yield (QY), is extremely low. The prototypical 2D material molybdenum disulfide (MoS2) is reported to have a maximum QY of 0.6%, which indicates a considerable defect density. Here we report on an air-stable, solution-based chemical treatment by an organic superacid, which uniformly enhances the photoluminescence and minority carrier lifetime of MoS2 monolayers by more than two orders of magnitude. The treatment eliminates defect-mediated nonradiative recombination, thus resulting in a final QY of more than 95%, with a longest-observed lifetime of 10.8 ± 0.6 nanoseconds. Our ability to obtain optoelectronic monolayers with near-perfect properties opens the door for the development of highly efficient light-emitting diodes, lasers, and solar cells based on 2D materials. Authors: Matin Amani, Der-Hsien Lien, Daisuke Kiriya, Jun Xiao, Angelica Azcatl, Jiyoung Noh, Surabhi R. Madhvapathy, Rafik Addou, Santosh KC, Madan Dubey, Kyeongjae Cho, Robert M. Wallace, Si-Chen Lee, Jr-Hau He, Joel W. Ager, Xiang Zhang, Eli Yablonovitch, Ali Javey
Categories: Journal Articles