bluuebunny/crossref_metadata_2025_split huggingface dataset:
L-asparagine crystals with wide gap semiconductor features: Optical absorption measurements and density functional theory computations
Authors: Zanatta G. , Gottfried C. , Silva A. M. , Caetano E. W. S. , Sales F. A. M. , Freire V. N. 
Published: April 2014

Results of optical absorption measurements are presented together with calculated structural, electronic, and optical properties for the anhydrous monoclinic L-asparagine crystal. Density functional theory (DFT) within the generalized gradient approximation (GGA) including dispersion effects (TS, Grimme) was employed to perform the calculations. The optical absorption measurements revealed that the anhydrous monoclinic L-asparagine crystal is a wide band gap material with 4.95 eV main gap energy. DFT-GGA+TS simulations, on the other hand, produced structural parameters in very good agreement with X-ray data. The lattice parameter differences Δa, Δb, Δc between theory and experiment were as small as 0.020, 0.051, and 0.022 Å, respectively. The calculated band gap energy is smaller than the experimental data by about 15%, with a 4.23 eV indirect band gap corresponding to Z → Γ and Z → β transitions. Three other indirect band gaps of 4.30 eV, 4.32 eV, and 4.36 eV are assigned to α3 → Γ, α1 → Γ, and α2 → Γ transitions, respectively. Δ-sol computations, on the other hand, predict a main band gap of 5.00 eV, just 50 meV above the experimental value. Electronic wavefunctions mainly originating from O 2p–carboxyl, C 2p–side chain, and C 2p–carboxyl orbitals contribute most significantly to the highest valence and lowest conduction energy bands, respectively. By varying the lattice parameters from their converged equilibrium values, we show that the unit cell is less stiff along the b direction than for the a and c directions. Effective mass calculations suggest that hole transport behavior is more anisotropic than electron transport, but the mass values allow for some charge mobility except along a direction perpendicular to the molecular layers of L-asparagine which form the crystal, so anhydrous monoclinic L-asparagine crystals could behave as wide gap semiconductors. Finally, the calculations point to a high degree of optical anisotropy for the absorption and complex dielectric function, with more structured curves for incident light polarized along the 100 and 101 directions.
Bcl2L13 is a ceramide synthase inhibitor in glioblastoma
Authors: Jensen Samuel A. , Calvert Andrea E. , Volpert Giora , Kouri Fotini M. , Hurley Lisa A. , Luciano Janina P. , Wu Yongfei , Chalastanis Alexandra , Futerman Anthony H. , Stegh Alexander H. 
Published: April 2014

Significance
Molecular mechanisms of therapy (apoptosis) resistance in cancer are poorly understood. Here, we have identified Bcl2-like 13 (Bcl2L13) as a ceramide synthase inhibitor that is overexpressed in glioblastoma (GBM) and other malignancies. Bcl2L13 inhibits therapy-induced apoptosis and promotes GBM tumor growth in vivo. Mechanistically, Bcl2L13 binds to proapoptotic ceramide synthases 2 (CerS2) and 6 (CerS6) and blocks CerS2/6 complex formation and activity. Correspondingly, CerS2/6 activity and Bcl2L13 abundance are inversely correlated in GBM tumors, thereby providing a molecular explanation for the low levels of proapoptotic ceramide species in high-grade gliomas, which are associated with poor survival. To our knowledge, this work provides the first evidence of direct regulation of CerS activity by a Bcl-2 family member and establishes the Bcl2L13–CerS axis as a target for therapeutic intervention.
From a structural average to the conformational ensemble of a DNA bulge
Authors: Shi Xuesong , Beauchamp Kyle A. , Harbury Pehr B. , Herschlag Daniel 
Published: April 2014

Significance
Obtaining the conformational ensembles of biological macromolecules, beyond average structures, is extremely challenging but necessary for a complete understanding of their folding and functions. Such insights may also lead to the rational design of therapeutics that can target less-ordered macromolecules and may advance the design of nanostructures and nanomachines from nucleic acids. We have applied X-ray interferometry to estimate the conformational ensemble of a small-model macromolecule, a DNA bulge, representative of helix–junction–helix building blocks of natural RNAs and designed DNA nanostructures. The measured ensemble, in combination with molecular dynamics simulations, provides testable atomic-level models. X-ray interferometry is extremely sensitive and can detect changes in the ensemble arising from different bulge sequences and solution salt conditions.
Methanogenic burst in the end-Permian carbon cycle
Authors: Rothman Daniel H. , Fournier Gregory P. , French Katherine L. , Alm Eric J. , Boyle Edward A. , Cao Changqun , Summons Roger E. 
Published: April 2014

SignificanceThe end-Permian extinction is the most severe biotic crisis in the fossil record. Its occurrence has been attributed to increased CO2levels deriving from massive Siberian volcanism. However, such arguments have been difficult to justify quantitatively. We propose that the disruption of the carbon cycle resulted from the emergence of a new microbial metabolic pathway that enabled efficient conversion of marine organic carbon to methane. The methanogenic expansion was catalyzed by nickel associated with the volcanic event. We support this hypothesis with an analysis of carbon isotopic changes leading up to the extinction, phylogenetic analysis of methanogenic archaea, and measurements of nickel concentrations in South China sediments. Our results highlight the sensitivity of the Earth system to microbial evolution.
Redirecting intracellular trafficking and the secretion pattern of FSH dramatically enhances ovarian function in mice
Authors: Wang Huizhen , Larson Melissa , Jablonka-Shariff Albina , Pearl Christopher A. , Miller William L. , Conn P. Michael , Boime Irving , Kumar T. Rajendra 
Published: April 2014

SignificanceAlthough the two pituitary gonadotropins luteinizing hormone (LH) and FSH are synthesized in the same cell, gonadotrope, their intracellular trafficking and secretion pattern are distinct. LH is released as pulses via the regulated pathway, whereas FSH is constitutively secreted. Why this hormone-specific pattern has evolved and whether the target organ, the ovary, senses specific hormone release pattern is not understood. In this paper, a gonadotrope-specific sorting determinant on LH has been identified, and FSH was diverted into the LH secretory pathway in vivo. FSH released like LH from pituitary dramatically enhanced the ovarian responses. Our studies provide a molecular basis for the evolution of distinct patterns of gonadotropin secretion and explain the origin of estrus cycles in mammals.
Understanding the mechanism of proteasome 20S core particle gating
Authors: Latham Michael P. , Sekhar Ashok , Kay Lewis E. 
Published: April 2014

Significance
The proteasome plays a critical role in regulating cellular homeostasis by degrading target protein substrates. Gating residues that are part of the barrel-like proteasome structure provide a barrier to prevent inadvertent proteolysis. With NMR spectroscopy, the mechanism by which the gates interconvert between open and closed states is studied. We show that collisions with water molecules provide a driving force for gate interconversion and that the process takes place via many small steps that involve protein segments smaller than 4 Å. The effect of cellular lysate on proteasome gating is explored, establishing that gating equilibria and kinetics are not perturbed relative to buffer solutions under conditions of similar viscosity.
Oxytocin promotes group-serving dishonesty
Authors: Shalvi Shaul , De Dreu Carsten K. W. 
Published: April 2014

SignificanceVery little is known about the biological foundations of immoral behavior. We report here the results of a double-blind, placebo-controlled experiment showing that the hormone oxytocin promotes group-serving dishonesty. Compared with participants receiving placebo, participants receiving oxytocin lied more to benefit their groups, did so quicker, and did so without expectation of reciprocal dishonesty from their group members. A control setting ruled out that oxytocin drives self-serving dishonesty. These findings support the functional approach to morality and reveal the underlying biological circuitries associated with group-serving dishonesty.
Observing (non)linear lattice dynamics in graphite by ultrafast Kikuchi diffraction
Authors: Liang Wenxi , Vanacore Giovanni M. , Zewail Ahmed H. 
Published: April 2014

Significance
Mechanical, electrical, and thermal properties of materials are governed by the nature of constituent atoms and their motions. Mapping atomic motions in the nonequilibrium regime, and thus the linear and nonlinear responses to stimuli, is nontrivial to achieve. Here, we report the methodology of ultrafast electron diffraction, enabling visualization of the atoms in motion. By using a special variant called Kikuchi diffraction, we map out the response of the lattice of nanoscale graphite. Following an impulsive excitation, two types of motions are resolved, one involving the reflections of strain between the two surfaces and the other involving planes of atoms in the transverse direction. The approach presented here has the potential for a wide range of applications.
Infectious Salmon Anemia (ISA) Virus: Infectivity in Seawater under Different Physical Conditions
Authors: Vike Siri , Oelckers Karin , Duesund Henrik , Erga Svein Rune , Gonzalez Javier , Hamre Børge , Frette Øyvind , Nylund Are 
Published: April 2014

Abstract
Infectious salmon anemia (ISA) virus (genus Isavirus, family Orthomyxoviridae), present in all major salmon producing countries, is the causative agent for a serious and commercially important disease affecting Atlantic Salmon Salmo salar. Nearly all ISA outbreaks occur in the marine production phase and knowledge about survival time for ISA virions in seawater is crucial for an adequate strategy to combat the disease. To acquire knowledge about this important factor, a study of ISA virus exposed to four different physical conditions was carried out. The virions’ survival was tested in sterile seawater, sterile seawater with normal ultraviolet light radiation (UVR), natural seawater, and natural seawater with UVR. During the 72-h experiment both presence of ISA virus RNA and the infectivity of ISA virions were monitored. The result of this study showed that the infectivity of ISA virions is lost within 3 h of exposure to natural seawater or sterile seawater with UVR. However, it was possible to detect ISA virus RNA throughout the experimental period. This indicates that the effect of both UVR and biological activity of natural seawater limits the survival time of ISA virions under normal conditions. The survival time of ISA virions in sterile seawater was less than 24 h. Based on the available literature and the present study it is not very likely that passive horizontal transmission in seawater over long distances can occur. This is due to the following factors: (1) the effect of UVR and biological activity on ISA virions infectivity found in the present study, (2) the speed and dilution effect in seawater currents in salmon farming areas, (3) the temperature during the major outbreak periods, and (4) the need for an infective dose of ISA virions to reach naive Atlantic Salmon.
Received August 22, 2013; accepted November 7, 2013
European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases Evidence‐Based Guidelines for the Management of Acute Gastroenteritis in Children in Europe
Authors: Guarino Alfredo , Ashkenazi Shai , Gendrel Dominique , Lo Vecchio Andrea , Shamir Raanan , Szajewska Hania 
Published: April 2014

ABSTRACTObjectives:These guidelines update and extend evidence‐based indications for the management of children with acute gastroenteritis in Europe.Methods:The guideline development group formulated questions, identified data, and formulated recommendations. The latter were graded with the Muir Gray system and, in parallel, with the Grading of Recommendations, Assessment, Development and Evaluations system.Results:Gastroenteritis severity is linked to etiology, and rotavirus is the most severe infectious agent and is frequently associated with dehydration. Dehydration reflects severity and should be monitored by established score systems. Investigations are generally not needed. Oral rehydration with hypoosmolar solution is the major treatment and should start as soon as possible. Breast‐feeding should not be interrupted. Regular feeding should continue with no dietary changes including milk. Data suggest that in the hospital setting, in non–breast‐fed infants and young children, lactose‐free feeds can be considered in the management of gastroenteritis. Active therapy may reduce the duration and severity of diarrhea. Effective interventions include administration of specific probiotics such as Lactobacillus GG or Saccharomyces boulardii, diosmectite or racecadotril. Anti‐infectious drugs should be given in exceptional cases. Ondansetron is effective against vomiting, but its routine use requires safety clearance given the warning about severe cardiac effects. Hospitalization should generally be reserved for children requiring enteral/parenteral rehydration; most cases may be managed in an outpatients setting. Enteral rehydration is superior to intravenous rehydration. Ultrarapid schemes of intravenous rehydration are not superior to standard schemes and may be associated with higher readmission rates.Conclusions:Acute gastroenteritis is best managed using a few simple, well‐defined medical interventions.
Mucosal Healing in Children With Treated Celiac Disease
Authors: Ghazzawi Youssef , Rubio‐Tapia Alberto , Murray Joseph A. , Absah Imad 
Published: April 2014

ABSTRACTObjectives:Limited data suggest complete mucosal healing in treated children with celiac disease (CD), but recent data from adult endoscopic biopsies have shown substantial numbers with persistent mucosal injury. We aimed to assess the rate of mucosal healing and indications for repeat small bowel (SB) biopsy in children with CD.Methods:We retrospectively reviewed records of children (ages 1–18 years) with CD who underwent a second SB biopsy. All of the children were seen at Mayo Clinic (Rochester, MN) from January 1997 through June 2013.Results:Forty children were identified (14 boys); average age at diagnosis was 8.5 years. Indications for second SB biopsy were abdominal pain (n = 20), diarrhea (n = 7), constipation (n = 5), non–celiac‐related concern (n = 2), follow‐up (n = 5), and persistent serology (n = 1). Average time between biopsies was 24 months (range 4–120 months). Histology on the second biopsy showed complete healing (n = 25), intraepithelial lymphocytes (n = 9), and persistent villous atrophy (n = 6). Of these, 3 patients had partial villous atrophy and 3 had with complete villous atrophy. Persistent villous atrophy was observed in 2 of 20 patients with abdominal pain and 1 of 7 with diarrhea. All of the patients with persistent constipation (n = 5) had complete resolution.Conclusions:Mucosal healing in children with CD may not be complete as previously assumed. Abdominal pain was the most common indication for repeating the SB biopsy. Persistence of abdominal pain, diarrhea, and constipation was poorly associated with persistence of mucosal injury.
Dynamics and Organization of Cortical Microtubules as Revealed by Superresolution Structured Illumination Microscopy
Authors: Komis George , Mistrik Martin , Šamajová Olga , Doskočilová Anna , Ovečka Miroslav , Illés Peter , Bartek Jiri , Šamaj Jozef 
Published: April 2014

AbstractPlants employ acentrosomal mechanisms to organize cortical microtubule arrays essential for cell growth and differentiation. Using structured illumination microscopy (SIM) adopted for the optimal documentation of Arabidopsis (Arabidopsis thaliana) hypocotyl epidermal cells, dynamic cortical microtubules labeled with green fluorescent protein fused to the microtubule-binding domain of the mammalian microtubule-associated protein MAP4 and with green fluorescent protein-fused to the alpha tubulin6 were comparatively recorded in wild-type Arabidopsis plants and in the mitogen-activated protein kinase mutant mpk4 possessing the former microtubule marker. The mpk4 mutant exhibits extensive microtubule bundling, due to increased abundance and reduced phosphorylation of the microtubule-associated protein MAP65-1, thus providing a very useful genetic tool to record intrabundle microtubule dynamics at the subdiffraction level. SIM imaging revealed nano-sized defects in microtubule bundling, spatially resolved microtubule branching and release, and finally allowed the quantification of individual microtubules within cortical bundles. Time-lapse SIM imaging allowed the visualization of subdiffraction, short-lived excursions of the microtubule plus end, and dynamic instability behavior of both ends during free, intrabundle, or microtubule-templated microtubule growth and shrinkage. Finally, short, rigid, and nondynamic microtubule bundles in the mpk4 mutant were observed to glide along the parent microtubule in a tip-wise manner. In conclusion, this study demonstrates the potential of SIM for superresolution time-lapse imaging of plant cells, showing unprecedented details accompanying microtubule dynamic organization.
Optimal planning for mitigating the impacts of roads on wildlife
Authors: Polak Tal , Rhodes Jonathan R. , Jones Darryl , Possingham Hugh P. 
Published: April 2014

Summary

Roads have a significant impact on wildlife world‐wide. Two of the ways to mitigate the impact of roads are to improve connectivity and reduce mortality through fences and wildlife crossings. However, these are expensive actions that will have different effects in different places. Thus, deciding where and how to act in order to achieve the greatest return on investment is crucial. Currently, there are no quantitative approaches to prioritize different road mitigation options.

Here, we use a decision science framework to determine the most cost‐effective combination of actions to mitigate the effects of roads on wildlife under budget constraints. We illustrate our approach using a case study of a threatened koala Phascolarctos cinereus population in south‐east Queensland. We applied a spatially explicit population model to explore the benefits of three kinds of mitigation actions: no action at all and fences with or without crossings, on different road segments.

We explored the trade‐off between expected koala population size, relative to the best outcome, and budget. There is a strong demand for mitigation as the already declining population was reduced even further when no mitigation was employed, while applying the most cost‐effective combination of mitigation actions minimized that decline. Additionally, uncertainty in species attributes (speed of crossing a road and population growth rate) affected population viability but not the decision about which suite of actions (mitigation measures) to take – so our advice on the best action is robust to uncertainty even if the outcome is not. Most importantly, the trade‐off curves between investment and population size are almost linear in this case study. Hence, there is no cheap solution and any reduction in the budget will result in a substantial reduction in expected population size.

Synthesis and applications. This is the first time that the problem of mitigating the effects of roads on wildlife was formulated mathematically and systematically using decision science. Our approach is adaptable to a diversity of species and systems affected by road mortality allowing flexibility for a range of mitigation actions and biological outcomes. Our method will allow managers and decision‐makers to increase the efficiency of mitigation actions.
Satellite remote sensing for applied ecologists: opportunities and challenges
Authors: Pettorelli Nathalie , Laurance William F. , O'Brien Timothy G. , Wegmann Martin , Nagendra Harini , Turner Woody 
Published: April 2014

Summary

Habitat loss and degradation, overexploitation, climate change and the spread of invasive species are drastically depleting the Earth's biological diversity, leading to detrimental impacts on ecosystem services and human well‐being.

Our ability to monitor the state of biodiversity and the impacts of global environmental change on this natural capital is fundamental to designing effective adaptation and mitigation strategies for preventing further loss of biological diversity. This requires the scientific community to assess spatio‐temporal changes in the distribution of abiotic conditions (e.g. temperature, rainfall) and in the distribution, structure, composition and functioning of ecosystems.

The potential for satellite remote sensing (SRS) to provide key data has been highlighted by many researchers, with SRS offering repeatable, standardized and verifiable information on long‐term trends in biodiversity indicators. SRS permits one to address questions on scales inaccessible to ground‐based methods alone, facilitating the development of an integrated approach to natural resource management, where biodiversity, pressures to biodiversity and consequences of management decisions can all be monitored.

Synthesis and applications. Here, we provide an interdisciplinary perspective on the prospects of satellite remote sensing (SRS) for ecological applications, reviewing established avenues and highlighting new research and technological developments that have a high potential to make a difference in environmental management. We also discuss current barriers to the ecological application of SRS‐based approaches and identify possible ways to overcome some of these limitations.