Read by QxMD icon Read

Science Advances

Domagoj Baretić, Hannah K Pollard, David I Fisher, Christopher M Johnson, Balaji Santhanam, Caroline M Truman, Tomas Kouba, Alan R Fersht, Christopher Phillips, Roger L Williams
ATM (ataxia-telangiectasia mutated) is a phosphatidylinositol 3-kinase-related protein kinase (PIKK) best known for its role in DNA damage response. ATM also functions in oxidative stress response, insulin signaling, and neurogenesis. Our electron cryomicroscopy (cryo-EM) suggests that human ATM is in a dynamic equilibrium between closed and open dimers. In the closed state, the PIKK regulatory domain blocks the peptide substrate-binding site, suggesting that this conformation may represent an inactive or basally active enzyme...
May 2017: Science Advances
Martin Glavinović, Michael Krause, Linju Yang, John A McLeod, Lijia Liu, Kim M Baines, Tomislav Friščić, Jean-Philip Lumb
Replacing molecular chlorine and hydrochloric acid with less energy- and risk-intensive reagents would markedly improve the environmental impact of metal manufacturing at a time when demand for metals is rapidly increasing. We describe a recyclable quinone/catechol redox platform that provides an innovative replacement for elemental chlorine and hydrochloric acid in the conversion of either germanium metal or germanium dioxide to a germanium tetrachloride substitute. Germanium is classified as a "critical" element based on its high dispersion in the environment, growing demand, and lack of suitable substitutes...
May 2017: Science Advances
Takuya Hosokai, Hiroyuki Matsuzaki, Hajime Nakanotani, Katsumi Tokumaru, Tetsuo Tsutsui, Akihiro Furube, Keirou Nasu, Hiroko Nomura, Masayuki Yahiro, Chihaya Adachi
The design of organic compounds with nearly no gap between the first excited singlet (S1) and triplet (T1) states has been demonstrated to result in an efficient spin-flip transition from the T1 to S1 state, that is, reverse intersystem crossing (RISC), and facilitate light emission as thermally activated delayed fluorescence (TADF). However, many TADF molecules have shown that a relatively appreciable energy difference between the S1 and T1 states (~0.2 eV) could also result in a high RISC rate. We revealed from a comprehensive study of optical properties of TADF molecules that the formation of delocalized states is the key to efficient RISC and identified a chemical template for these materials...
May 2017: Science Advances
Shigeki Kawai, Tomohiko Nishiuchi, Takuya Kodama, Peter Spijker, Rémy Pawlak, Tobias Meier, John Tracey, Takashi Kubo, Ernst Meyer, Adam S Foster
The hydrogen atom-the smallest and most abundant atom-is of utmost importance in physics and chemistry. Although many analysis methods have been applied to its study, direct observation of hydrogen atoms in a single molecule remains largely unexplored. We use atomic force microscopy (AFM) to resolve the outermost hydrogen atoms of propellane molecules via very weak C═O⋅⋅⋅H-C hydrogen bonding just before the onset of Pauli repulsion. The direct measurement of the interaction with a hydrogen atom paves the way for the identification of three-dimensional molecules such as DNAs and polymers, building the capabilities of AFM toward quantitative probing of local chemical reactivity...
May 2017: Science Advances
Ke Liu, Yuan Xu, Weiting Wang, Shi-Biao Zheng, Tanay Roy, Suman Kundu, Madhavi Chand, Arpit Ranadive, Rajamani Vijay, Yipu Song, Luming Duan, Luyan Sun
Wave-particle complementarity lies at the heart of quantum mechanics. To illustrate this mysterious feature, Wheeler proposed the delayed-choice experiment, where a quantum system manifests the wave- or particle-like attribute, depending on the experimental arrangement, which is made after the system has entered the interferometer. In recent quantum delayed-choice experiments, these two complementary behaviors were simultaneously observed with a quantum interferometer in a superposition of being closed and open...
May 2017: Science Advances
Hongbo Ma, Jeffrey A Nittrouer, Kensuke Naito, Xudong Fu, Yuanfeng Zhang, Andrew J Moodie, Yuanjian Wang, Baosheng Wu, Gary Parker
Sedimentary dispersal systems with fine-grained beds are common, yet the physics of sediment movement within them remains poorly constrained. We analyze sediment transport data for the best-documented, fine-grained river worldwide, the Huanghe (Yellow River) of China, where sediment flux is underpredicted by an order of magnitude according to well-accepted sediment transport relations. Our theoretical framework, bolstered by field observations, demonstrates that the Huanghe tends toward upper-stage plane bed, yielding minimal form drag, thus markedly enhancing sediment transport efficiency...
May 2017: Science Advances
Steven J Lade, L Jamila Haider, Gustav Engström, Maja Schlüter
The poverty trap concept strongly influences current research and policy on poverty alleviation. Financial or technological inputs intended to "push" the rural poor out of a poverty trap have had many successes but have also failed unexpectedly with serious ecological and social consequences that can reinforce poverty. Resilience thinking can help to (i) understand how these failures emerge from the complex relationships between humans and the ecosystems on which they depend and (ii) navigate diverse poverty alleviation strategies, such as transformative change, that may instead be required...
May 2017: Science Advances
Stefan Chmiela, Alexandre Tkatchenko, Huziel E Sauceda, Igor Poltavsky, Kristof T Schütt, Klaus-Robert Müller
Using conservation of energy-a fundamental property of closed classical and quantum mechanical systems-we develop an efficient gradient-domain machine learning (GDML) approach to construct accurate molecular force fields using a restricted number of samples from ab initio molecular dynamics (AIMD) trajectories. The GDML implementation is able to reproduce global potential energy surfaces of intermediate-sized molecules with an accuracy of 0.3 kcal mol(-1) for energies and 1 kcal mol(-1) Å̊(-1) for atomic forces using only 1000 conformational geometries for training...
May 2017: Science Advances
Igor Melnikov, Vitaly Polovinkin, Kirill Kovalev, Ivan Gushchin, Mikhail Shevtsov, Vitaly Shevchenko, Alexey Mishin, Alexey Alekseev, Francisco Rodriguez-Valera, Valentin Borshchevskiy, Vadim Cherezov, Gordon A Leonard, Valentin Gordeliy, Alexander Popov
We describe a fast, easy, and potentially universal method for the de novo solution of the crystal structures of membrane proteins via iodide-single-wavelength anomalous diffraction (I-SAD). The potential universality of the method is based on a common feature of membrane proteins-the availability at the hydrophobic-hydrophilic interface of positively charged amino acid residues with which iodide strongly interacts. We demonstrate the solution using I-SAD of four crystal structures representing different classes of membrane proteins, including a human G protein-coupled receptor (GPCR), and we show that I-SAD can be applied using data collection strategies based on either standard or serial x-ray crystallography techniques...
May 2017: Science Advances
Binsong Li, Kaifu Bian, Xiaowang Zhou, Ping Lu, Sheng Liu, Igal Brener, Michael Sinclair, Ting Luk, Hattie Schunk, Leanne Alarid, Paul G Clem, Zhongwu Wang, Hongyou Fan
Oriented attachment (OA) of synthetic nanocrystals is emerging as an effective means of fabricating low-dimensional nanoscale materials. However, OA relies on energetically favorable nanocrystal facets to grow nanostructured materials. Consequently, nanostructures synthesized through OA are generally limited to a specific crystal facet in their final morphology. We report our discovery that high-pressure compression can induce consolidation of spherical CdSe nanocrystal arrays, leading to unexpected one-dimensional semiconductor nanowires that do not exhibit the typical crystal facet...
May 2017: Science Advances
Denise Zujur, Kosuke Kanke, Alexander C Lichtler, Hironori Hojo, Ung-Il Chung, Shinsuke Ohba
The development of in vitro models for the maintenance and differentiation of pluripotent stem cells (PSCs) is an active area of stem cell research. The strategies used so far are based mainly on two-dimensional (2D) cultures, in which cellular phenotypes are regulated by soluble factors. We show that a 3D culture system with atelocollagen porous scaffolds can significantly improve the outcome of the current platforms intended for the maintenance and lineage specification of mouse PSCs (mPSCs). Unlike 2D conditions, the 3D conditions maintained the undifferentiated state of mouse embryonic stem cells (mESCs) without exogenous stimulation and also supported endoderm, mesoderm, and ectoderm differentiation of mESCs under serum-free conditions...
May 2017: Science Advances
Chirag Garg, See-Hun Yang, Timothy Phung, Aakash Pushp, Stuart S P Parkin
The use of current pulses to move domain walls along nanowires is one of the most exciting developments in spintronics over the past decade. We show that changing the sign of the curvature of a nanowire changes the speed of chiral Néel domain walls in perpendicularly magnetized nanowires by up to a factor of 10. The domain walls have an increased or decreased velocity in wires of a given curvature, independent of the domain wall chirality and the sign of the current-induced spin-orbit torques. Thus, adjacent domain walls move at different speeds...
May 2017: Science Advances
Christopher S O'Bryan, Tapomoy Bhattacharjee, Samuel Hart, Christopher P Kabb, Kyle D Schulze, Indrasena Chilakala, Brent S Sumerlin, W Gregory Sawyer, Thomas E Angelini
The widespread prevalence of commercial products made from microgels illustrates the immense practical value of harnessing the jamming transition; there are countless ways to use soft, solid materials that fluidize and become solid again with small variations in applied stress. The traditional routes of microgel synthesis produce materials that predominantly swell in aqueous solvents or, less often, in aggressive organic solvents, constraining ways that these exceptionally useful materials can be used. For example, aqueous microgels have been used as the foundation of three-dimensional (3D) bioprinting applications, yet the incompatibility of available microgels with nonpolar liquids, such as oils, limits their use in 3D printing with oil-based materials, such as silicone...
May 2017: Science Advances
Maria Mooshammer, Florian Hofhansl, Alexander H Frank, Wolfgang Wanek, Ieda Hämmerle, Sonja Leitner, Jörg Schnecker, Birgit Wild, Margarete Watzka, Katharina M Keiblinger, Sophie Zechmeister-Boltenstern, Andreas Richter
Predicted changes in the intensity and frequency of climate extremes urge a better mechanistic understanding of the stress response of microbially mediated carbon (C) and nutrient cycling processes. We analyzed the resistance and resilience of microbial C, nitrogen (N), and phosphorus (P) cycling processes and microbial community composition in decomposing plant litter to transient, but severe, temperature disturbances, namely, freeze-thaw and heat. Disturbances led temporarily to a more rapid cycling of C and N but caused a down-regulation of P cycling...
May 2017: Science Advances
Christos C Ioannou, Indar W Ramnarine, Colin J Torney
Collective decisions play a major role in the benefits that animals gain from living in groups. Although the mechanisms of how groups collectively make decisions have been extensively researched, the response of within-group dynamics to ecological conditions is virtually unknown, despite adaptation to the environment being a cornerstone in biology. We investigate how within-group interactions during exploration of a novel environment are shaped by predation, a major influence on the behavior of prey species...
May 2017: Science Advances
Shuichi Murakami, Motoaki Hirayama, Ryo Okugawa, Takashi Miyake
A band gap for electronic states in crystals governs various properties of solids, such as transport, optical, and magnetic properties. Its estimation and control have been an important issue in solid-state physics. The band gap can be controlled externally by various parameters, such as pressure, atomic compositions, and external field. Sometimes, the gap even collapses by tuning some parameter. In the field of topological insulators, this closing of the gap at a time-reversal invariant momentum indicates a band inversion, that is, it leads to a topological phase transition from a normal insulator to a topological insulator...
May 2017: Science Advances
Xiaodi Yu, David Veesler, Melody G Campbell, Mary E Barry, Francisco J Asturias, Michael A Barry, Vijay S Reddy
Human adenoviruses (HAdVs) cause acute respiratory, ocular, and gastroenteric diseases and are also frequently used as gene and vaccine delivery vectors. Unlike the archetype human adenovirus C5 (HAdV-C5), human adenovirus D26 (HAdV-D26) belongs to species-D HAdVs, which target different cellular receptors, and is differentially recognized by immune surveillance mechanisms. HAdV-D26 is being championed as a lower seroprevalent vaccine and oncolytic vector in preclinical and human clinical studies. To understand the molecular basis for their distinct biological properties and independently validate the structures of minor proteins, we determined the first structure of species-D HAdV at 3...
May 2017: Science Advances
Jeroen Groeneveld, Jorijntje Henderiks, Willem Renema, Cecilia M McHugh, David De Vleeschouwer, Beth A Christensen, Craig S Fulthorpe, Lars Reuning, Stephen J Gallagher, Kara Bogus, Gerald Auer, Takeshige Ishiwa
Global climate underwent a major reorganization when the Antarctic ice sheet expanded ~14 million years ago (Ma) (1). This event affected global atmospheric circulation, including the strength and position of the westerlies and the Intertropical Convergence Zone (ITCZ), and, therefore, precipitation patterns (2-5). We present new shallow-marine sediment records from the continental shelf of Australia (International Ocean Discovery Program Sites U1459 and U1464) providing the first empirical evidence linking high-latitude cooling around Antarctica to climate change in the (sub)tropics during the Miocene...
May 2017: Science Advances
Leto Peel, Daniel B Larremore, Aaron Clauset
Across many scientific domains, there is a common need to automatically extract a simplified view or coarse-graining of how a complex system's components interact. This general task is called community detection in networks and is analogous to searching for clusters in independent vector data. It is common to evaluate the performance of community detection algorithms by their ability to find so-called ground truth communities. This works well in synthetic networks with planted communities because these networks' links are formed explicitly based on those known communities...
May 2017: Science Advances
Carmen M Halabi, Thomas J Broekelmann, Michelle Lin, Vivian S Lee, Mon-Li Chu, Robert P Mecham
Homozygous or compound heterozygous mutations in fibulin-4 (FBLN4) lead to autosomal recessive cutis laxa type 1B (ARCL1B), a multisystem disorder characterized by significant cardiovascular abnormalities, including abnormal elastin assembly, arterial tortuosity, and aortic aneurysms. We sought to determine the consequences of a human disease-causing mutation in FBLN4 (E57K) on the cardiovascular system and vascular elastic fibers in a mouse model of ARCL1B. Fbln4(E57K/E57K) mice were hypertensive and developed arterial elongation, tortuosity, and ascending aortic aneurysms...
May 2017: Science Advances
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"