bluuebunny/crossref_metadata_2025 huggingface dataset:
Epitaxial Ni-Mn-Ga-Co thin films on PMN-PT substrates for multicaloric applications
Authors: Schleicher B. , Niemann R. , Diestel A. , Hühne R. , Schultz L. , Fähler S.
Published: August 2015

Multicaloric stacks consisting of a magnetocaloric film on a piezoelectric substrate promise improved caloric properties as the transition temperature can be controlled by both magnetic and electric fields. We present epitaxially grown magnetocaloric Ni-Mn-Ga-Co thin films on ferroelectric Pb(Mg1/3Nb2/3)0.72Ti0.28O3 substrates. Structure and microstructure of two samples, being in the austenitic and martensitic state at room temperature, are investigated by X-ray diffraction in two- and four-circle geometry and by atomic force microscopy. In addition, high temperature magnetometry was performed on the latter sample. The combination of these methods allows separating the influence of epitaxial growth and martensitic transformation. A preferential alignment of twin boundaries is observed already in the as-deposited state, which indicates the presence of prestress, without applying an electric field to the substrate. A temperature-magnetic field phase diagram is presented, which demonstrates the inverse magnetocaloric effect of the epitaxial Ni-Mn-Ga-Co film.
Simulation of biochemical reactions with time-dependent rates by the rejection-based algorithm
Authors: Thanh Vo Hong , Priami Corrado
Published: August 2015

We address the problem of simulating biochemical reaction networks with time-dependent rates and propose a new algorithm based on our rejection-based stochastic simulation algorithm (RSSA) [Thanh et al., J. Chem. Phys. 141(13), 134116 (2014)]. The computation for selecting next reaction firings by our time-dependent RSSA (tRSSA) is computationally efficient. Furthermore, the generated trajectory is exact by exploiting the rejection-based mechanism. We benchmark tRSSA on different biological systems with varying forms of reaction rates to demonstrate its applicability and efficiency. We reveal that for nontrivial cases, the selection of reaction firings in existing algorithms introduces approximations because the integration of reaction rates is very computationally demanding and simplifying assumptions are introduced. The selection of the next reaction firing by our approach is easier while preserving the exactness.
Underwater microwave ignition of hydrophobic thermite powder enabled by the bubble-marble effect
Authors: Meir Yehuda , Jerby Eli
Published: August 2015

Highly energetic thermite reactions could be useful for a variety of combustion and material-processing applications, but their usability is yet limited by their hard ignition conditions. Furthermore, in virtue of their zero-oxygen balance, exothermic thermite reactions may also occur underwater. However, this feature is also hard to utilize because of the hydrophobic properties of the thermite powder, and its tendency to agglomerate on the water surface rather than to sink into the water. The recently discovered bubble-marble (BM) effect enables the insertion and confinement of a thermite-powder batch into water by a magnetic field. Here, we present a phenomenon of underwater ignition of a thermite-BM by localized microwaves. The thermite combustion underwater is observed in-situ, and its microwave absorption and optical spectral emission are detected. The vapour pressure generated by the thermite reaction is measured and compared to theory. The combustion products are examined ex-situ by X-ray photo-electron spectroscopy which verifies the thermite reaction. Potential applications of this underwater combustion effect are considered, e.g., for detonation, wet welding, thermal drilling, material processing, thrust generation, and composite-material production, also for other oxygen-free environments.
Effect of Fe-doping on nonlinear optical responses and carrier trapping dynamics in GaN single crystals
Authors: Fang Yu , Wu Xingzhi , Yang Junyi , Xiao Zhengguo , Yang Yong , Zhou Feng , Song Yinglin
Published: August 2015

We presented a quantitative study on the Fe-doping concentration dependence of optical nonlinearities and ultrafast carrier dynamics in Fe-doped GaN (GaN:Fe) single crystals using picosecond Z-scan and femtosecond pump-probe with phase object techniques under two-photon excitation. In contrast to the two-photon absorption that was found to be independent on the Fe-doping, the nonlinear refraction decreased with the Fe concentration due to the fast carrier trapping effect of Fe3+/Fe2+ deep acceptors, which simultaneously acted as an efficient non-radiative recombination channels for excess carriers. Remarkably, compared to that of Si-doped GaN bulk crystal, the free-carrier refraction effect in GaN:Fe crystals was found to be enhanced considerably since Fe-doping and the effective carrier lifetime (∼10 ps) could be tuned over three orders of magnitude at high Fe-doping level of 1 × 1019 cm−3.
Possible coexistence of cycloidal phases, magnetic field reversal of polarization, and memory effect in multiferroic R0.5Dy0.5MnO3 (R = Eu and Gd)
Authors: De Chandan , Sundaresan A.
Published: August 2015

We report the occurrence of both ab and bc cycloidal ordering of Mn-spins at different temperatures and their possible coexistence at low temperatures in the polycrystalline mixed rare-earth compounds, R0.5Dy0.5MnO3 (R = Eu and Gd), which exhibit extraordinary magnetoelectric properties. While the polarization of Gd0.5Dy0.5MnO3 is comparable to TbMnO3, the compound Eu0.5Dy0.5MnO3 shows high value of polarization. However, both of them show giant magnetic tunability and exhibit large magnetocapacitance whose sign changes across the two cycloidal ordering temperatures. Intriguingly, the electric polarization can be reversed upon ramping up or ramping down the magnetic field, which has not been observed for any of the RMnO3 system. Most strikingly, these compounds show non-volatile ferroelectric memory effect even in the paraelectric and paramagnetic region (TC ≤ T ≤ 80 K). We attribute these remarkable properties to the coexistence of ab and bc cycloidal ordered phases.
Port of Los Angeles—Shanghai Municipal Transportation Commission EcoPartnership on shore power
Authors: Cannon C. , Gao Y. , Wunder L.
Published: August 2015

In July 2014, the Port of Los Angeles (POLA) and the Shanghai Municipal Transportation Commission (SMTC, formerly Port of Shanghai) entered into an EcoPartnership focused on reducing air emissions at both ports by instituting and expanding the use of Shore Power on ocean-going vessels while at berth. In 2004, POLA became the first port in the world to have a container ship plug into shore power through their Alternative Maritime Power™ (AMP™) program. Since then, the shore power plug-in program has expanded to include all container terminals and the cruise terminal at POLA, and significant air emission reductions have occurred as a direct result of those efforts. The EcoPartnership builds upon that experience to support the development of SMTC's capabilities in technology, strategy, and policy development as it relates to shore power. POLA and SMTC developed annual milestones extending through the term of the EcoPartnership agreement with a goal of successfully setting up and implementing a Shore Power program at a Shanghai terminal, including the successful operation of four shore power-ready terminals by 2017. Through their term in the EcoPartnership program, both ports will continue to collaborate and learn from each other on a variety of environmental issues. The potential benefits of the EcoPartnership extend much further. It is envisioned that coordinated development of compatible shore power infrastructure will encourage ship owners to more rapidly convert their fleet to allow ships to plug in, expediting emission reductions at both ports. Additionally, this project will serve as an example that other ports across the globe can use to implement shore power programs at their facilities.
McMillan-Rowell like oscillations in a superconductor-InAs/GaSb-superconductor junction
Authors: Shi Xiaoyan , Yu Wenlong , Hawkins S. D. , Klem J. F. , Pan W.
Published: August 2015

We have fabricated a superconductor (Ta)-InAs/GaSb bilayer-superconductor (Ta) junction device that has a long mean free path and can preserve the wavelike properties of particles (electrons and holes) inside the junction. Differential conductance measurements were carried out at low temperatures in this device, and McMillan-Rowell like oscillations (MROs) were observed. Surprisingly, a much larger Fermi velocity, compared to that from Shubnikov-de Haas oscillations, was obtained from the frequency of MROs. Possible mechanisms are discussed for this discrepancy.
Atomic-scale and pit-free flattening of GaN by combination of plasma pretreatment and time-controlled chemical mechanical polishing
Authors: Deng Hui , Endo Katsuyoshi , Yamamura Kazuya
Published: August 2015

Chemical mechanical polishing (CMP) combined with atmospheric-pressure plasma pretreatment was applied to a GaN (0001) substrate. The irradiation of a CF4-containing plasma was proven to be very useful for modifying the surface of GaN. When CMP was conducted on a plasma-irradiated surface, a modified layer of GaF3 acted as a protective layer on GaN by preventing the formation of etch pits. Within a short duration (8 min) of CMP using a commercially available CeO2 slurry, an atomically flat surface with a root mean square (rms) roughness of 0.11 nm was obtained. Moreover, etch pits, which are inevitably introduced in conventional CMP, could not be observed at the dislocation sites on the polished GaN surface. It was revealed that CMP combined with the plasma pretreatment was very effective for obtaining a pit-free and atomically flat GaN surface.
Vibrational properties of epitaxial Bi4Te3 films as studied by Raman spectroscopy
Authors: Xu Hao , Song Yuxin , Pan Wenwu , Chen Qimiao , Wu Xiaoyan , Lu Pengfei , Gong Qian , Wang Shumin
Published: August 2015

Bi4Te3, as one of the phases of the binary Bi–Te system, shares many similarities with Bi2Te3, which is known as a topological insulator and thermoelectric material. We report the micro-Raman spectroscopy study of 50 nm Bi4Te3 films on Si substrates prepared by molecular beam epitaxy. Raman spectra of Bi4Te3 films completely resolve the six predicted Raman-active phonon modes for the first time. Structural features and Raman tensors of Bi4Te3 films are introduced. According to the wavenumbers and assignments of the six eigenpeaks in the Raman spectra of Bi4Te3 films, it is found that the Raman-active phonon oscillations in Bi4Te3 films exhibit the vibrational properties of those in both Bi and Bi2Te3 films.
Linking fecal bacteria in rivers to landscape, geochemical, and hydrologic factors and sources at the basin scale
Authors: Verhougstraete Marc P. , Martin Sherry L. , Kendall Anthony D. , Hyndman David W. , Rose Joan B.
Published: August 2015

Significance

New microbial source-tracking tools can be used to elucidate important nonpoint sources of water quality degradation and potential human health risks at large scales. Pollution arising from septic system discharges is likely more important than previously realized. Identifying these sources and providing reference levels for water quality provides a basis to assess water quality trends and ultimately remediate degraded areas.
21st century United States emissions mitigation could increase water stress more than the climate change it is mitigating
Authors: Hejazi Mohamad I. , Voisin Nathalie , Liu Lu , Bramer Lisa M. , Fortin Daniel C. , Hathaway John E. , Huang Maoyi , Kyle Page , Leung L. Ruby , Li Hong-Yi , Liu Ying , Patel Pralit L. , Pulsipher Trenton C. , Rice Jennie S. , Tesfa Teklu K. , Vernon Chris R. , Zhou Yuyu
Published: August 2015

Significance

Devising sustainable climate change mitigation policies with attention to potential synergies and constraints within the climate–energy–water nexus is the subject of ongoing integrated modeling efforts. This study employs a regional integrated assessment model and a regional Earth system model at high spatial and temporal resolutions in the Unites States to compare the implications of two of the representative concentration pathways under consistent socioeconomics. The results clearly show, for the first time to our knowledge, that climate change mitigation policies, if not designed with careful attention to water resources, could increase the magnitude, spatial coverage, and frequency of water deficits. The results challenge the general perception that mitigation that aims at reducing warming also would alleviate water deficits in the future.
Critical waves and the length problem of biology
Authors: Laughlin Robert B.
Published: August 2015

Significance

This paper invokes physical principles to answer the question of why pure reaction–diffusion ideas do not produce a satisfactory explanation of biological growth and form. Two ideas have been missing. One is that oscillation is necessary to achieve the necessary design stability and plasticity. The other is that the system must be tuned to criticality to stabilize the propagation velocity, thus enabling clocks to function as meter sticks. The larger significance is twofold: First, a fundamental piece of the machinery of life is probably invisible to present-day biochemical methods because they are too slow. Second, the simplicity of growth and form identified a century ago by D'Arcy Thompson is probably a symptom of biological engineering strategies, not primitive law.
Heat dissipation guides activation in signaling proteins
Authors: Weber Jeffrey K. , Shukla Diwakar , Pande Vijay S.
Published: August 2015

Significance

As with their macroscopic counterparts, the moving parts of nanoscale protein machines grow hot while in operation. A portion of the energy biomolecules harness to perform meaningful work is always dissipated as heat into the surroundings. Here, we feature a methodology by which dominant dissipative trajectories can be extracted from detailed models of protein dynamics. In two important classes of signaling proteins [kinases and G-protein–coupled receptors (GPCRs)], we find that the regions of phase space in which heat is evolved are closely connected to the structural dynamics these proteins use to transmit signals. This schematic might be used to probe the true functional dynamics of biomolecules that drive a wide array of cellular architectures and ultimately sustain the steady state of life.
Large-scale evidence of dependency length minimization in 37 languages
Authors: Futrell Richard , Mahowald Kyle , Gibson Edward
Published: August 2015

Significance

We provide the first large-scale, quantitative, cross-linguistic evidence for a universal syntactic property of languages: that dependency lengths are shorter than chance. Our work supports long-standing ideas that speakers prefer word orders with short dependency lengths and that languages do not enforce word orders with long dependency lengths. Dependency length minimization is well motivated because it allows for more efficient parsing and generation of natural language. Over the last 20 y, the hypothesis of a pressure to minimize dependency length has been invoked to explain many of the most striking recurring properties of languages. Our broad-coverage findings support those explanations.
Nucleotides regulate the mechanical hierarchy between subdomains of the nucleotide binding domain of the Hsp70 chaperone DnaK
Authors: Bauer Daniela , Merz Dale R. , Pelz Benjamin , Theisen Kelly E. , Yacyshyn Gail , Mokranjac Dejana , Dima Ruxandra I. , Rief Matthias , Žoldák Gabriel
Published: August 2015

Significance

Binding of nucleotides to proteins is arguably the most important regulation process in our body. How the signal of nucleotide binding gets transmitted through the protein eventually changing its conformation and function is, however, still a poorly understood process. In this study, we set out to investigate the energy balance within the nucleotide binding domain (NBD) of the heat shock protein of 70 kDa (Hsp70) chaperone DnaK. Using single molecule force spectroscopy and theoretical simulations, we were able to dissect the contribution of the individual subdomains of the NBD to the mechanical stability of the protein and identified how the mechanical hierarchy is modulated by nucleotide binding. Our results have immediate consequences for the signal transduction within the whole actin/sugar kinase superfamily.
Three types of rescue can avert extinction in a changing environment
Authors: Hufbauer Ruth A. , Szűcs Marianna , Kasyon Emily , Youngberg Courtney , Koontz Michael J. , Richards Christopher , Tuff Ty , Melbourne Brett A.
Published: August 2015

Significance

Preventing extinction of small populations in rapidly changing environments is crucial to long-term preservation of diversity, because the creation of large reserves is often not feasible. An option immediately available to managers is bringing migrants in to increase size or improve genetic composition of populations at risk. We experimentally manipulate different types and combinations of migrants to evaluate which will be most effective in rescuing populations from extinction. We find that migration of numerous individuals can reduce the probability of extinction. However, migration of just a few genetically distinct individuals both reduces probability of extinction and dramatically increases fitness and population size. We suggest managers with limited conservation resources should prioritize genetic rescue over increasing demographic size for small populations.
Fork rotation and DNA precatenation are restricted during DNA replication to prevent chromosomal instability
Authors: Schalbetter Stephanie A. , Mansoubi Sahar , Chambers Anna L. , Downs Jessica A. , Baxter Jonathan
Published: August 2015

Significance

Genome inheritance requires the complete resolution of all intertwines within parental DNA. This is facilitated by fork rotation and precatenation of the newly replicated DNA. However, the general importance and frequency of fork rotation in vivo are poorly understood. We find that the evolutionarily conserved Timeless and Tipin proteins actively inhibit fork rotation in budding yeast. In their presence, fork rotation appears restricted to hard-to-replicate fragile sites. In their absence, excessive fork rotation leads to damage accumulating in the replicated sister chromatids, especially at known yeast fragile sites. Therefore, fork rotation appears to be restricted to contexts where it is absolutely required for unwinding, and this restriction is required to prevent precatenation inducing excessive chromosomal fragility.
Aldosterone-stimulating somatic gene mutations are common in normal adrenal glands
Authors: Nishimoto Koshiro , Tomlins Scott A. , Kuick Rork , Cani Andi K. , Giordano Thomas J. , Hovelson Daniel H. , Liu Chia-Jen , Sanjanwala Aalok R. , Edwards Michael A. , Gomez-Sanchez Celso E. , Nanba Kazutaka , Rainey William E.
Published: August 2015

Significance

Primary aldosteronism (PA) represents the most common adrenal disease and cause of secondary hypertension. However, little is known regarding adrenal cellular origins. Recently, subcapsular aldosterone-producing cell clusters (APCCs) were observed in normal adrenals. We hypothesize that APCCs are a contributor to PA. Here, we characterized the APCC transcriptome and show that
CYP11B2
expression is increased compared with the rest of the adrenal cortex. We also show that many APCCs harbor known aldosterone-producing adenoma (APA)-related ion channels/pumps (
ATPase, Na

+

/K

+

transporting, α1-polypeptide
and
calcium channel, voltage-dependent, L-type, α1D-subunit
) mutations that stimulate
CYP11B2
expression and aldosterone production. Importantly, the mutation spectrum seen in APCCs differs from that reported for APA. These results provide molecular support for APCC as a precursor of PA.
Pleiotropic age-dependent effects of mitochondrial dysfunction on epidermal stem cells
Authors: Velarde Michael C. , Demaria Marco , Melov Simon , Campisi Judith
Published: August 2015

Significance

Mitochondrial damage can accelerate features of aging, including impaired tissue regeneration, but little is known about how aging and this damage interact to impair tissue renewal. We show that mitochondrial oxidative stress in the epidermis alters wound healing depending on age. Epidermal mitochondrial damage accelerated wound closure in young mice; however, in older mice, this damage limited epidermal cell proliferation and reduced epidermal stem cell numbers, leading to delayed wound closure. Our findings uncover a surprising beneficial effect of mitochondrial dysfunction at young age (accelerated wound closure), and a potential mechanism for the reduced epidermal regeneration at older ages (stem cell depletion).
Essential role for polymerase specialization in cellular nonhomologous end joining
Authors: Pryor John M. , Waters Crystal A. , Aza Ana , Asagoshi Kenjiro , Strom Christina , Mieczkowski Piotr A. , Blanco Luis , Ramsden Dale A.
Published: August 2015

Significance

Nonhomologous end joining (NHEJ) is a DNA double-strand break repair pathway required for development of the adaptive immune response, maintenance of cellular proliferative capacity, and the response to several commonly used cancer treatments. A major challenge faced by this pathway is that chromosome breaks can have dirty end structures, making them difficult to repair. We show here that two mammalian DNA polymerases have an unexpectedly pivotal role in helping resolve such ends. Each is proficient in different contexts and has a differing impact on repair fidelity. This work sheds light on how NHEJ has evolved to be flexible during repair and identifies two polymerases as critical for this process.
Synthetic physical interactions map kinetochore regulators and regions sensitive to constitutive Cdc14 localization
Authors: Ólafsson Guðjón , Thorpe Peter H.
Published: August 2015

Significance

The localization of proteins within the cell is assumed to be important for their function. However, we have limited understanding of protein relocalization in response to genetic changes or drug treatments and almost no understanding of the effects of protein relocation on cellular homeostasis. To address this, we have developed a method to systematically create protein fusions between a query protein and most other proteins in the cell. As proof of principle, we relocalized proteins to the kinetochore, a large protein complex essential for chromosome segregation and cell division. We identify a number of proteins that inhibit cell division via the kinetochore. One such interaction establishes a critical role for specific phosphorylation in kinetochore function.
Nectar vs. pollen loading affects the tradeoff between flight stability and maneuverability in bumblebees
Authors: Mountcastle Andrew M. , Ravi Sridhar , Combes Stacey A.
Published: August 2015

Significance

Many insects carry substantial loads during flight. Although this behavior is often critical for survival and reproduction, few studies have examined its consequences for flight performance. Bumblebees regularly carry two types of loads in different locations: pollen on their legs or nectar in their abdomen. We found that when bees carry a pollen load rather than a nectar load, they are more stable but less maneuverable in flight, supporting the concept of a tradeoff between stability and maneuverability—a notion that is frequently suggested but has rarely been tested, particularly in flying insects. Our findings also suggest that wind conditions may influence what resources pollinators choose to collect, which would have important consequences for pollination dynamics and colony fitness.
Astrocytes phagocytose focal dystrophies from shortening myelin segments in the optic nerve of
Xenopus laevis
at metamorphosis
Authors: Mills Elizabeth A. , Davis Chung-ha O. , Bushong Eric A. , Boassa Daniela , Kim Keun-Young , Ellisman Mark H. , Marsh-Armstrong Nicholas
Published: August 2015

Significance

Myelin segments facilitate fast conduction along axons, and thus the rapid transmission of information in the nervous system. In the absence of pathology, myelin segments are generally regarded as highly stable structures with plasticity limited to growth-related increases in myelin thickness. We discovered that existing myelin segments are also capable of rapid shortening and demonstrate that shortening involves a characteristic focal dystrophy that develops at the contact point with a phagocytic astrocyte. These astrocytes internalize large quantities of myelin from shortening segments using known phagocytic machinery in a developmentally regulated manner. This mechanism likely contributes to other instances of myelin remodeling and prevents the persistence of potentially pathological myelin dystrophies.
FXR1P is a GSK3β substrate regulating mood and emotion processing
Authors: Del’Guidice Thomas , Latapy Camille , Rampino Antonio , Khlghatyan Jivan , Lemasson Morgane , Gelao Barbara , Quarto Tiziana , Rizzo Giuseppe , Barbeau Annie , Lamarre Claude , Bertolino Alessandro , Blasi Giuseppe , Beaulieu Jean-Martin
Published: August 2015

Significance

This study provides a cellular mechanism for the regulation of behavioral dimensions pertinent to mood disorders. Inhibition of glycogen synthase kinase 3β (GSK3β) is a shared action of drugs used for bipolar disorder. However, the substrates through which this kinase regulates mood are not known. We identified fragile X mental retardation-related protein 1 (FXR1P) as a substrate for GSK3β. Phosphorylation of FXR1P by GSK3β would lead to its down-regulation. Overexpression of FXR1P in the mouse prelimbic cortex elicits behavioral responses comparable to those of drugs inhibiting GSK3β. Furthermore, functional gene polymorphisms affecting FXR1P or GSK3β gene expression interact to regulate emotional brain responsiveness and stability in humans. These observations indicate that regulation of FXR1P by GSK3β contributes to regulating mood and emotion processing.
The genetics of human infertility by functional interrogation of SNPs in mice
Authors: Singh Priti , Schimenti John C.
Published: August 2015

Significance

Although infertility is a highly prevalent disease with a major genetic component, the underlying genetic causes are unknown in the vast majority of patients. The complexity of sperm and egg production has confounded most efforts to address the genetics of human infertility. We have developed an experimental strategy for identifying infertility-causing mutations that exist in human populations. This strategy exploits the expanding databases of human genetic variation to computationally identify potential infertility mutations, then mimic them in mice by CRISPR/Cas genome editing technology. The mice are then evaluated for whether the human mutation renders them infertile. This technology can be used to establish a permanent resource of validated disease-causing genetic variants in infertility and other diseases.
Ubiquitination by March-I prevents MHC class II recycling and promotes MHC class II turnover in antigen-presenting cells
Authors: Cho Kyung-Jin , Walseng Even , Ishido Satoshi , Roche Paul A.
Published: August 2015

Significance

Expression of MHC class II–peptide complexes (pMHC-II) on the surface of antigen-presenting cells (APCs) is required for a wide variety of CD4 T-cell–dependent immunological processes. Regulation of pMHC-II biosynthesis and degradation are, therefore, essential for optimal APC function. We now show that ubiquitination of pMHC-II by the E3 ubiquitin ligase March-I prevents pMHC-II recycling and targets newly synthesized pMHC-II for lysosomal degradation in resting dendritic cells and B cells. Activation of these cells terminates March-I expression, terminates pMHC-II ubiquitination, and prevents pMHC-II degradation by promoting efficient pMHC-II recycling. Our study demonstrates that rapid recycling “spares” internalized pMHC-II from degradation in activated APCs, thereby increasing the probability of efficient pMHC-II interaction with CD4 T cells.
Long-term social dynamics drive loss of function in pathogenic bacteria
Authors: Andersen Sandra Breum , Marvig Rasmus Lykke , Molin Søren , Krogh Johansen Helle , Griffin Ashleigh S.
Published: August 2015

Significance

Laboratory experiments show that bacteria have surprisingly complex social lives: Like humans, they can cooperate but also cheat each other. Cooperation could benefit bacteria causing infection by coordinating attack and producing toxins in a collective effort. But can cheaters, exploiting the work of others, affect the outcome of infection? We show that populations of bacteria causing chronic lung infections in cystic fibrosis patients contain cheaters that freeload to the point where cooperation no longer pays off by not producing a compound that helps them steal iron from blood. Bad news for bacteria but good for us if we can find ways to meddle in their social lives.
Persistence of the dominant soil phylum
Acidobacteria
by trace gas scavenging
Authors: Greening Chris , Carere Carlo R. , Rushton-Green Rowena , Harold Liam K. , Hards Kiel , Taylor Matthew C. , Morales Sergio E. , Stott Matthew B. , Cook Gregory M.
Published: August 2015

Significance

The mechanisms that the “dormant microbial majority” use to remain energized in nutrient-starved soil ecosystems have long remained elusive. In this work, we used an isolate of the highly abundant but poorly understood soil phylum
Acidobacteria
as a model for understanding microbial persistence mechanisms. When the bacterium entered a persistent state due to nutrient-exhaustion, we showed it could scavenge the trace concentrations of molecular hydrogen gas (H
2
) found in ambient air using a specialized high-affinity enzyme. These findings demonstrate that
Acidobacteria
can consume H
2
and contribute to global hydrogen cycling. We propose that consumption of trace gases such as H
2
provides a dependable general mechanism for dominant soil phyla to generate the maintenance energy required for long-term survival.
Mapping the conformation of a client protein through the Hsp70 functional cycle
Authors: Sekhar Ashok , Rosenzweig Rina , Bouvignies Guillaume , Kay Lewis E.
Published: August 2015

Significance

Hsp70 chaperones are key components of the cellular proteostasis network. The ATP-dependent interaction of Hsp70 with its substrates prevents aggregation and promotes their correct folding and maturation. Here we investigate the impact of Hsp70 binding on the conformation of a client substrate using nuclear magnetic resonance spectroscopy. Our experiments provide a model for Hsp70 action in which the substrate can adopt substantial amounts of secondary structure even in the globally unfolded Hsp70-bound state. Moreover, the substrate conformation does not evolve as a function of the Hsp70 nucleotide state, demonstrating that the large structural changes in Hsp70 resulting from ATP binding and hydrolysis do not perform conformational work on the bound substrate or lead to changes in client protein conformation.
New model to explain tooth wear with implications for microwear formation and diet reconstruction
Authors: Xia Jing , Zheng Jing , Huang Diaodiao , Tian Z. Ryan , Chen Lei , Zhou Zhongrong , Ungar Peter S. , Qian Linmao
Published: August 2015

Significance

Dental microwear is among the most common proxies paleontologists use for diet reconstruction. Recent models have suggested that while quartz grit adherent to food produces wear of tooth enamel, softer particles, such as silica phytoliths found in many plants, do not. Some have therefore suggested that microwear patterns better reflect habitat than diet. This is important to paleobiologists because reconstructions of species from the earliest vertebrates to human ancestors have relied on dental microwear as a proxy for diet. Here we present an in vitro study demonstrating that softer particles produce microwear under conditions mimicking chewing. Enamel wear occurs not because an abrasive is hard but because it exceeds the binding force of proteins that hold together hydroxyapatite crystallites.
High-resolution epitope mapping by HX MS reveals the pathogenic mechanism and a possible therapy for autoimmune TTP syndrome
Authors: Casina Veronica C. , Hu Wenbing , Mao Jian-Hua , Lu Rui-Nan , Hanby Hayley A. , Pickens Brandy , Kan Zhong-Yuan , Lim Woon K. , Mayne Leland , Ostertag Eric M. , Kacir Stephen , Siegel Don L. , Englander S. Walter , Zheng X. Long
Published: August 2015

Significance

Acquired thrombotic thrombocytopenic purpura (TTP) is primarily caused by autoantibodies that inhibit the ability of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) to proteolyze von Willebrand factor (VWF). The molecular mechanism of inhibition is not known. We used a hydrogen–deuterium exchange mass spectrometry (HX MS) method to determine at near–single-residue resolution the epitope of three monoclonal anti-ADAMTS13 autoantibodies isolated from TTP patients. Additional results show that the same autoantibody-binding epitope is responsible for ADAMTS13 binding to VWF to manage VWF proteolysis. These observations reveal the mechanism of autoimmune TTP and, together with the epitope determination, suggest a knowledge-based approach for finding a novel therapeutic.
SufB intein of
Mycobacterium tuberculosis
as a sensor for oxidative and nitrosative stresses
Authors: Topilina Natalya I. , Green Cathleen M. , Jayachandran Pradeepa , Kelley Danielle S. , Stanger Matthew J. , Piazza Carol Lyn , Nayak Sasmita , Belfort Marlene
Published: August 2015

Significance

For over two decades, inteins have been considered parasitic elements. However, recent examples of conditional protein splicing indicate that some inteins may have evolved a regulatory role in response to the environment. These cues result in fine-tuning of host protein function under conditions in which the proteins themselves are regulated. Here we report on the discovery that the
Mycobacterium tuberculosis
SufB intein when expressed in
Escherichia coli
possesses extraordinary sensitivity to oxidative and nitrosative stresses. These conditions are highly relevant to survival of mycobacterial pathogens. This work delivers a breakthrough in the understanding of regulation of protein splicing through cysteine chemistry, and proposes a new form of posttranslational control of the
M. tuberculosis
SufB protein.
Dietary changes of large herbivores in the Turkana Basin, Kenya from 4 to 1 Ma
Authors: Cerling Thure E. , Andanje Samuel A. , Blumenthal Scott A. , Brown Francis H. , Chritz Kendra L. , Harris John M. , Hart John A. , Kirera Francis M. , Kaleme Prince , Leakey Louise N. , Leakey Meave G. , Levin Naomi E. , Manthi Fredrick Kyalo , Passey Benjamin H. , Uno Kevin T.
Published: August 2015

Significance

Stable carbon isotopes give diet information for both modern and fossil mammals and can be used to classify diets as C
4
grazers, C
3
–C
4
mixed, or C
3
browsers. We show that diets of some major African herbivore lineages have significantly changed over the past 4 million years by comparing fossils from the Turkana Basin in Kenya with modern mammals from East and Central Africa. Some fossil assemblages have no modern analogues in East and Central Africa, suggesting different ecological functions for some mammals in the past as compared with their modern counterparts. The development of modern tropical grassland ecosystems are products of the coevolution of both grasses and herbivores.
Remembering and Telling: A Developmental Story
Authors: Nelson Katherine
Published: August 2015

Abstract The relation of narrative to the onset of autobiographical memory in early childhood is considered from the perspective of three sources of narrativity: (a) event knowledge, (b) parental talk about past and future events, and (c) knowl-edge of story schemata. Evidence from work on children's scripts and episodic memory indicates that both general and specific event knowledge is well estab-lished by 3 years of age. Evidence from the monologues of a 2 year old (Emily) indicated that parental talk about past and future events was available as a model for the child to use to formulate her own memories and anticipations in verbal form, and that she did indeed produce coherent accounts of past happenings and future activities based on, but going beyond, these models. By 3 years, however, Emily—and most children observed—could tell a good story about her own life's events, but did not recount a fictional story that had been read to her in the same coherent narrative mode. Both good memories and good stories seem to be based on representations of events influenced by parental models of narrative-type talk.(Psychology)
Perspectives on Embodiment: The Uses of Narrativity in Ethnographic Writing
Authors: Young Katharine
Published: August 2015

Abstract
Take as pivotal in anthropological discourse the invention of the category of the Other. Once invented, the category conjures up another realm, a realm inhabited by the Other and estranged from the realm of the self. Ethnographic writings are then constructed to get access to the Other. At issue, then, are how realms of experience are constellated with respect to each other, how they communicate, and how they coalesce. One name for these realm relations is dialogism. Under a dialogic description, the boundaries between self and Other become blurred, along with the boundaries between the universes of discourse they inhabit. Eth-nographic writings formulate relationships between realms in terms of conven-tions of perspective and voice. These conventions are anchored in the body. In particular, a hierarchy of modalities of perception informs a social scientific epistemology. In this article, the realm status of self and Other in anthropological discourse is investigated in three perspectives: the objective, the subjective, and what I call the intersubjective. Problems of access turn out to be artifacts of our invention of the category of the Other. (Ethnographic Writing)
Representing Discourse: The Rhetoric of Transcription
Authors: Mishler Elliot G.
Published: August 2015

Abstract Transcription is the general procedure used in studies of discourse to re-present speech as written text. Different notation systems have been proposed, and emphasis is often placed on achieving a high level of precision and accuracy of transcripts. In this article, transcription is treated as an instance of the general problem of the representation of reality that appears in diverse fields, such as photography and the biological and natural sciences. Three studies are examined where alternative transcripts of the same stretch of speech were presented and analyzed. This comparison shows how different transcript formats both reflect and reflexively support theoretical aims and interpretations and serve rhetorical functions. The essential indeterminancy and ambiguity of the relationship be-tween language and meaning, which has emerged from the widespread critique of naive realism, both sets the problem and provides the context within which we can understand transcription as an interpretive practice.(Sociolinguistics)
Nisa Revisited
Authors: Shostak Marjorie
Published: August 2015

Abstract A collaboration begun 20 years ago between Nisa, a !Kung San (Bushman) woman of northwestern Botswana, and myself, an American anthropologist, has affected both women's lives. In 1989, after a 14-year absence (and 8 years after the results of their collaboration was published: Nisa: The Life and Words of a !Kung Woman), I returned to meet Nisa again, now approximately 68 years old. Over the course of 10 new interviews, we discussed the changes that had taken place in Nisa's life, her aging process, her views on culture change, her future prospects, and the impact that the book and monetary payments (primarily in the form of cattle) have had on her life. Selected memories were also reviewed to explore whether time and additional years of living had affected her view of her life story.(Anthropology)
From Beginning to End: An Irish Life History
Authors: Gmelch Sharon
Published: August 2015

Abstract
This article discusses the two ends of the life-history process: the reasons for its undertaking and the research assumptions these engender, and the impact of the published account on readers. In doing so, I draw on my own experience in the research and writing of Nan: The Life of an Irish Travelling woman (Gmelch, 1986/1991) and upon the responses of Traveller and non-Traveller readers to this life history. (Ethnographic research; life-history interviewing, editing, and narra-tive construction; literary criticism)
Writing Kwaio Life Histories
Authors: Keesing Roger M.
Published: August 2015

Abstract
This article discusses the two ends of the life-history process: the reasons for its undertaking and the research assumptions these engender, and the impact of the published account on readers. In doing so, I draw on my own experience in the research and writing of Nan: The Life of an Irish Travelling woman (Gmelch, 1986/1991) and upon the responses of Traveller and non-Traveller readers to this life history. (Ethnographic research; life-history interviewing, editing, and narra-tive construction; literary criticism)
A Biographical Case Study of a Victimizer's Daughter's Strategy: Pseudo-Identification With the Victims of the Holocaust
Authors: Rosenthal Gabriele , Bar-On Dan
Published: August 2015

Abstract
Previous studies have shown that many children of former Nazi perpetrators either identify with their parents by denying their atrocities, by distancing them-selves emotionally from their parents, or by acknowledging their participation in the extermination process. Through a hermeneutical case study of the narrated life story of a Euthanasia physician's daughter, a type of strategy, which we defined as pseudo-identification with the victim, is reconstructed. The results of the analysis suggest that this is a repair strategy. Putting oneself in the role of one's parents' victim provides refuge from acknowledging possible identification with Nazism and its idols, as well as identifying oneself with the real victims of one's parents. In this case, the psychological consequences of this strategy are described: The woman still suffers from extermination anxieties which block further working through of the past. (Behavioral Sciences)
Roots of Response
Authors: Purcell-Gates Victoria
Published: August 2015

Abstract Response to literature involves a transaction between reader and author where meaning isconstructedby the reader, using the blueprints, or signs, provided by the author. According to Fish (1980a), readers and authors implicitly know the conventions of response by virtue of being members of the same interpretive community. This socially acquired knowledge enables readers and authors to conjointly create, identify, and respond to literature. Currently, increased re-search into the teaching and learning of literature has led to a renewed examina-tion of classroom techniques directed toward "teaching" response. This article presents data which suggests that many young children begin formal schooling with a predisposition, or readiness, for literary response. Evidence for this comes from a study of preliterate kindergarten children who were asked to "pretend to read" to a pretend child (doll) from a wordless picture book (Purcell-Gates, 1988). Cast in the authorial role, these children used language which proved to enhance and constrain imaging for reader response. This communicative compe-tence is interpreted through Fish's notion of an interpretive community within which literary conventions are implicitly learned. Knowledge of both the product and process of acquisition of this knowledge held by entering school children should inform discussions of instructional methodology regarding reader re-sponse.(Literacy Education)
Scripts and Projects as Modes of Understanding Political Actions: The Representation of Palestinians in Bestselling Literature
Authors: van Teeffelen Toine
Published: August 2015

Abstract This article analyzes the representation of Palestinian actions in Western bestsell-ing thrillers. Most of these actions can be understood through the application of scripts—cognitive structures of stereotypical action sequences. It is argued that the scriptal representations activate causal schemas of Palestinians and Arabs at both a psychological and a social level. The concept of script is set against that of project, characterized by a narrative understanding. It is shown how the need to make a story interesting and thus not completely stereotypical is met by, among others, the amplification of aspects of threatening scripts, and by a tension producing ambivalence toward Palestinian nationalism. In almost all cases a scriptal understanding remains privileged.(Qualitative Psychology, Cultural Studies)
Developing Autonomy for Tellers, Tales, and Telling in Family Narrative Events
Authors: Blum-Kulka Shoshana , Snow Catherine E.
Published: August 2015

Abstract
Dinner-table conversations are contexts in which children become socialized to local cultural rules regulating storytelling and may be able to achieve autonomy in telling stories, as tellers of stories, and in the content or tale recounted. Conversations from five American and five Israeli middle-class families and five American working-class families matched on family constellation generated 33, 40, and 15 narratives, respectively. Each of the groups demonstrated a different pattern on dimensions such as who participated in telling narratives, who initi-ated narratives, and how secondary narrators participated; Israeli family narra-tives were more collaborative but with relatively little child participation, whereas American middle-class children participated more by initiating their own narratives and American working-class children narrated in response to adult elicitation. All three groups demanded fidelity to truth and coherence in the tales children told, but many more of the narratives told in Israeli families had to do with events known to all the family members, whereas American children told stories about events unfamiliar to at least some family members. (Communication)
How to Tell a Good Story: The Intersection of Language and Affect in Children's Narratives
Authors: Reilly Judy
Published: August 2015

Abstract
This article reports two studies in which the developmental relationship be-tween affective and linguistic expression is explored by comparing the comple-mentary skills of storytelling (performance) and story construction (structure). In the first study, children of the two age groups (3- to 4-year-olds and 6- to 8-year-olds) were shown a picture book, Frog, Where Are You? (Mayer, 1979) and then asked to tell the story. Analyses of the data revealed a striking dif-ference in both story structure and storytelling performance. The older group consistently produced stories of greater length and complexity than those of the younger group; with respect to storytelling performance, however, 3- and 4-year-olds used significantly more affective elements of good storytelling than did the 7- and 8-year-olds. In a second study, ten 7- and 8-year-olds and ten 10- and 11-year-olds retold the same story, but to a 3-year-old. In this con-text, the 10- and 11-year-olds used significantly more affective devices, both linguistic and paralinguistic, than did the 7- and 8-year-olds. Considering both cognitive and discourse perspectives, the developmental implications of these findings are discussed.