bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive modelling of fire occurrences from different fire spread patterns in Mediterranean landscapes
Authors: Duane Andrea , Piqué Míriam , Castellnou Marc , Brotons Lluís
Published: April 2015

Fire regimes are shifting worldwide because of global changes. The relative contribution of climate, topography and vegetation greatly determines spatial and temporal variations in fire regimes, but the interplay of these factors is not yet well understood. We introduce here a novel classification of fires according to dominant fire spread pattern, an approach considered in operational firefighting, to help understand regional-scale spatial variability in fire regimes. Here, we studied whether climate, topography and fuel variables allowed the prediction of occurrences from different fire spread patterns in Catalonia, NE Spain. We used a correlative modelling approach based on maximum entropy methods, and examined, through variation partitioning, the relative contribution of different factors on determining their occurrence. Our results accurately predicted the occurrence of different fire spread patterns, and the results were consistent when temporal validation was conducted. Although forest fuel factors made a higher contribution to the occurrence of convective fires, wind-driven fires were strongly related to topographic and climate factors. These findings may have a strong impact on investigations into how fire regimes may be projected into the future under forecast global change as they suggest that future environmental changes may affect different fire spread patterns in an idiosyncratic manner.
Food base of the spotted hyena (Crocuta crocuta) in Ethiopia
Authors: Yirga Gidey , De Iongh Hans H. , Leirs Herwig , Gebrehiwot Kindeya , Deckers Jozef , Bauer Hans
Published: April 2015

Context
Livestock depredation and scavenging of waste by the spotted hyena (Crocuta crocuta) occurs widely across Ethiopia.

Aims
The aim of this study was to investigate the food base of the spotted hyena and livestock depredation across Ethiopia.

Methods
The diet of spotted hyenas was assessed in 17 randomly selected study sites across the country, including two national parks, by scat analysis. We conducted an extensive survey of livestock depredation and economic impact in 10 randomly selected subdistricts using semistructured interviews with 3080 randomly selected households.

Key results
We found that even spotted hyenas from national parks feed predominantly on anthropogenic waste. Households reported losses of 2230 domestic animals, 3.9% of their stock or an average annual financial loss of US$10.3 per household over the past five years. The diet of spotted hyenas showed only prey items of domestic origin except in Chebera Churchura National Park, where a few items of prey of wild species were found. Frequencies of prey remains of cattle, sheep, donkey and goat were highest in decreasing order.

Key conclusions
Survival of hyenas in Ethiopia is thus largely and widely dependent on management of livestock conflict and waste. Some hairs in scats originated from depredation, but most food intake is from waste dumps and slaughterhouses.

Implications
Waste management, spotted hyena persistence and environmental sanitation area are linked.
Community ecology in a changing environment: Perspectives from the Quaternary
Authors: Jackson Stephen T. , Blois Jessica L.
Published: April 2015

Community ecology and paleoecology are both concerned with the composition and structure of biotic assemblages but are largely disconnected. Community ecology focuses on existing species assemblages and recently has begun to integrate history (phylogeny and continental or intercontinental dispersal) to constrain community processes. This division has left a “missing middle”: Ecological and environmental processes occurring on timescales from decades to millennia are not yet fully incorporated into community ecology. Quaternary paleoecology has a wealth of data documenting ecological dynamics at these timescales, and both fields can benefit from greater interaction and articulation. We discuss ecological insights revealed by Quaternary terrestrial records, suggest foundations for bridging between the disciplines, and identify topics where the disciplines can engage to mutual benefit.
The fossil record of phenotypic integration and modularity: A deep-time perspective on developmental and evolutionary dynamics
Authors: Goswami Anjali , Binder Wendy J. , Meachen Julie , O’Keefe F. Robin
Published: April 2015

Significance

Variation is the raw material for evolution, but studies have yet to unify the effects of intrinsic genetic and developmental interactions that influence variation with the extrinsic factors that shape organismal diversity on a large scale. Analysis of phenotypic integration can bridge different facets of evolutionary study and address fundamental questions on developmental and evolutionary dynamics through deep time. Our study of Late Pleistocene saber-toothed cats and dire wolves demonstrates that developmental integration channeled increasing amounts of morphological variation through 27,000 years of climate change, validating results from laboratory-based studies with the natural experiments captured in the fossil record.
Changing the picture of Earth's earliest fossils (3.5–1.9 Ga) with new approaches and new discoveries
Authors: Brasier Martin D. , Antcliffe Jonathan , Saunders Martin , Wacey David
Published: April 2015

Significance

Precambrian fossils are essential for understanding the emergence of complex life. New analytical tools and new fossil discoveries are now changing the picture, allowing us to refine and extend our knowledge about the early fossil record. High-resolution data from 3.46-Ga Apex chert microbiota help us to test rigorous criteria for studying the early fossil record. Preservational windows in the 1.88-Ga Gunflint chert allow us to posit novel cellular forms, and emphasize the critical role played by the fossil record in understanding early biodiversity. Micromapping of 3.43-Ga Strelley Pool sandstone reveals microfossils preserved between sand grains from the earliest known shoreline, reminding us that many kinds of ancient habitat have yet to be explored in this way.
Convergence, divergence, and parallelism in marine biodiversity trends: Integrating present-day and fossil data
Authors: Huang Shan , Roy Kaustuv , Valentine James W. , Jablonski David
Published: April 2015

Significance

The fossil record can reveal the complex history behind present-day diversity patterns. For marine bivalves, similarities and differences in species diversity within lineages among regions are better explained by past extinction, origination, and immigration than by contrasts in today’s climates alone. A signature of more severe extinction in the western Atlantic relative to the western Pacific coast is still evident in the tropics, but not in the temperate zone, where more prolific diversification and/or immigration has allowed the western Atlantic to match or surpass eastern Pacific diversities for many lineages. Species persistence in the temperate zone is associated with broad geographic range prior to an extinction pulse ∼2−3 My ago, underscoring the importance of history for understanding modern biodiversity patterns.
Predicting traffic volumes and estimating the effects of shocks in massive transportation systems
Authors: Silva Ricardo , Kang Soong Moon , Airoldi Edoardo M.
Published: April 2015

Significance

We propose a new approach to analyzing massive transportation systems that leverages traffic information about individual travelers. The goals of the analysis are to quantify the effects of shocks in the system, such as line and station closures, and to predict traffic volumes. We conduct an in-depth statistical analysis of the Transport for London railway traffic system. The proposed methodology is unique in the way that past disruptions are used to predict unseen scenarios, by relying on simple physical assumptions of passenger flow and a system-wide model for origin–destination movement. The method is scalable, more accurate than blackbox approaches, and generalizable to other complex transportation systems. It therefore offers important insights to inform policies on urban transportation.
Heterogeneity of long-history migration explains cultural differences in reports of emotional expressivity and the functions of smiles
Authors: Rychlowska Magdalena , Miyamoto Yuri , Matsumoto David , Hess Ursula , Gilboa-Schechtman Eva , Kamble Shanmukh , Muluk Hamdi , Masuda Takahiko , Niedenthal Paula Marie
Published: April 2015

Significance

In an age of globalization, emotional understanding is the central problem of human interaction. Here, we show that historical heterogeneity, or the extent to which a country’s present-day population descends from numerous (vs. few) source countries, predicts cultural variation in norms for emotional expressivity. Reanalysis of cultural display rules from 32 countries reveals that historical heterogeneity is associated with norms favoring greater emotional expressivity. In addition, the results of a study of nine countries show that the belief that smiles signal social bonding motives vs. the negotiation of status in a social hierarchy is predicted by historical heterogeneity as well.
Phytoplankton adapt to changing ocean environments
Authors: Irwin Andrew J. , Finkel Zoe V. , Müller-Karger Frank E. , Troccoli Ghinaglia Luis
Published: April 2015

Significance

Most ecosystem models used to predict changes in community composition with climate change assume species’ responses to environmental conditions are genetically fixed on the century scale, but this hypothesis has not been tested. Using an oceanographic time series with directional environmental changes, we show here that many phytoplankton species are able to track, on average, modest changes in temperature and irradiance, but not decreases in limiting nutrient concentrations, on decadal timescales. This result suggests that models that use genetically fixed traits may not provide reasonable projections for changes in biological communities in response to climate change over decadal to longer timescales.
Amplified Arctic warming by phytoplankton under greenhouse warming
Authors: Park Jong-Yeon , Kug Jong-Seong , Bader Jürgen , Rolph Rebecca , Kwon Minho
Published: April 2015

Significance

One of the important impacts of marine phytoplankton on climate systems is the geophysical feedback by which chlorophyll and the related pigments in phytoplankton absorb solar radiation and then change sea surface temperature. Yet such biogeophysical impact is still not considered in many climate projections by state-of-the-art climate models, nor is its impact on the future climate quantified. This study shows that, by conducting global warming simulations with and without an active marine ecosystem model, the biogeophysical effect of future phytoplankton changes amplifies Arctic warming by 20%. Given the close linkage between the Arctic and global climate, the biologically enhanced Arctic warming can significantly modify future estimates of global climate change, and therefore it needs to be considered as a possible future scenario.
Odorant receptors regulate the final glomerular coalescence of olfactory sensory neuron axons
Authors: Rodriguez-Gil Diego J. , Bartel Dianna L. , Jaspers Austin W. , Mobley Arie S. , Imamura Fumiaki , Greer Charles A.
Published: April 2015

Significance

The constant generation of olfactory sensory neurons throughout life makes the system appealing for studies of the mechanisms of axon extension and connectivity. Understanding the mechanisms leading to the genesis of these new neurons is fundamental for the development of therapeutic treatments. We provide here, to our knowledge, the first detailed analysis of the sequential steps leading toward fully differentiated sensory neurons. We show that odorant receptors are not involved in the initial steps of differentiation, but only later in the final process of maturation. Moreover, the proteins that we studied here also have been implicated in normal and pathophysiological events ranging from kidney function to cancer development, making our data valuable across different disciplines.
Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands
Authors: Douglas Peter M. J. , Pagani Mark , Canuto Marcello A. , Brenner Mark , Hodell David A. , Eglinton Timothy I. , Curtis Jason H.
Published: April 2015

Significance

The Terminal Classic decline of the Maya civilization represents a key example of ancient societal collapse that may have been caused by climate change, but there are inconsistencies between paleoclimate and archaeological evidence regarding the spatial distribution of droughts and sociopolitical disintegration. We conducted a new analysis of regional drought intensity that shows drought was most severe in the region with the strongest societal collapse. We also found that an earlier drought interval coincided with agricultural intensification, suggesting that the ancient Maya adapted to previous episodes of climate drying, but could not cope with the more extreme droughts of the Terminal Classic.
Caenorhabditis elegans
microRNAs of the
let-7
family act in innate immune response circuits and confer robust developmental timing against pathogen stress
Authors: Ren Zhiji , Ambros Victor R.
Published: April 2015

Significance

Proper animal development requires the robust execution of cell fates under stressful conditions. In
Caenorhabditis elegans
, reciprocal interactions between heterochronic genes and the p38 innate immune pathway help to coordinate development with pathogen defense. Importantly, the robustness of developmental cell fate expression during infection depends on functional redundancy among genes encoding microRNAs (miRNAs) of the
let-7
family. These findings underscore the importance of miRNA pathways in conferring robustness to developmental programs under stressful conditions and highlight roles for heterochronic genes not only as developmental timers but also as modulators of innate immune responses. The
let-7
family miRNAs and p38 innate immune pathway are evolutionarily conserved; therefore, this study presents implications for similar integration of these two pathways in other animal systems.
Tryptophan-to-heme electron transfer in ferrous myoglobins
Authors: Monni Roberto , Al Haddad André , van Mourik Frank , Auböck Gerald , Chergui Majed
Published: April 2015

Significance

We demonstrate the occurrence of tryptophan (Trp) to heme electron transfer (ET) in ferrous myoglobins by ultrafast UV spectroscopy. The ET gives rise to the theoretically predicted, low-valence Fe(II)(porph●−) anion radical, which we observe for the first time to our knowledge under physiological conditions. These results highlight the generality of Trp–porphyrin electron transfer events in heme proteins and question the systematic use of Trp fluorescence in FRET studies of protein dynamics.
Endosymbiosis undone by stepwise elimination of the plastid in a parasitic dinoflagellate
Authors: Gornik Sebastian G. , Febrimarsa  , Cassin Andrew M. , MacRae James I. , Ramaprasad Abhinay , Rchiad Zineb , McConville Malcolm J. , Bacic Antony , McFadden Geoffrey I. , Pain Arnab , Waller Ross F.
Published: April 2015

Significance

Endosymbiotic organelles are a defining feature of eukaryotes—the last common ancestor and all extant eukaryotes possess at least a mitochondrial derivative. Although mitochondria and plastids are identified with aerobic ATP synthesis and photosynthesis, respectively, their retention by their host cells requires the merging and integration of many, often redundant, metabolic pathways. As a result, complex metabolic interdependencies arise between these formerly independent cells. Complete loss of endosymbiotic organelles, even where aerobic respiration or photosynthesis is lost, is exceedingly difficult, as demonstrated by persistence of organelles throughout secondary anaerobes and parasites. Here, we identify a rare but clear case of plastid loss in a parasitic alga and detail the metabolic disentanglement that was required to achieve this exceptional evolutionary event.
Accessory NUMM (NDUFS6) subunit harbors a Zn-binding site and is essential for biogenesis of mitochondrial complex I
Authors: Kmita Katarzyna , Wirth Christophe , Warnau Judith , Guerrero-Castillo Sergio , Hunte Carola , Hummer Gerhard , Kaila Ville R. I. , Zwicker Klaus , Brandt Ulrich , Zickermann Volker
Published: April 2015

Significance

Respiratory complex I is the largest membrane protein complex in mitochondria and has a central function in energy metabolism. Numerous human diseases are linked with complex I dysfunction or assembly defects. The concerted assembly of more than 40 subunits and the insertion of cofactors is aided by specific chaperones. In addition to eight FeS clusters, complex I comprises a Zn-binding site of unknown function. Combining X-ray structural analysis of complex I crystals with quantum chemical modeling and proteomic and spectroscopic analysis of a purified assembly intermediate, we show that accessory subunit NUMM (human ortholog NDUFS6) binds Zn at the interface of two functional modules of the enzyme complex and is required for a specific step of complex I biogenesis.
Comparative analyses of animal-tracking data reveal ecological significance of endothermy in fishes
Authors: Watanabe Yuuki Y. , Goldman Kenneth J. , Caselle Jennifer E. , Chapman Demian D. , Papastamatiou Yannis P.
Published: April 2015

Significance

Most fishes are cold-blooded, but tunas and some sharks (e.g., white sharks) maintain their exercising muscles warmer than ambient waters. This ability is a remarkable example of convergent evolution because bony and cartilaginous fishes diverged as long as 450 million years ago. What are the ecological benefits driving the evolution of warm muscles in fishes? Despite extensive discussion, no previous studies have tested a simple possibility that fishes with warm muscles may swim faster in nature. We demonstrate that fishes with warm muscles swim faster and perform larger-scale annual migrations than similar-sized cold-blooded fishes. Our results suggest that warm muscles enhance power output and, thus, cruising speeds, which may enable longer-distance migrations and potentially greater access to seasonally available resources.
Organometallic rotaxane dendrimers with fourth-generation mechanically interlocked branches
Authors: Wang Wei , Chen Li-Jun , Wang Xu-Qing , Sun Bin , Li Xiaopeng , Zhang Yanyan , Shi Jiameng , Yu Yihua , Zhang Li , Liu Minghua , Yang Hai-Bo
Published: April 2015

Significance

In this study, the preparation of organometallic rotaxane dendrimers with a well-defined topological structure and enhanced rigidity was developed. Starting from a simple rotaxane building block, high-generation rotaxane branched dendrimers were synthesized and characterized. The fourth-generation structure described is among the highest-generation organometallic rotaxane dendrimers reported to date. The introduction of pillar[5]arene rotaxane units activates dynamic features in the dendrimer and enhances the rigidity of each branch of the supermolecules. This research offers a facile approach to the construction of high-generation rotaxane branched dendrimer, which not only enriches the library of rotaxne dendrimer but also provides the further insight into their applications as supramolecular dynamic materials.
Kibble–Zurek mechanism in colloidal monolayers
Authors: Deutschländer Sven , Dillmann Patrick , Maret Georg , Keim Peter
Published: April 2015

Significance

Spontaneous symmetry breaking describes a variety of transformations from high- to low-temperature phases and applies to cosmological concepts as well as atomic systems. T. W. B. Kibble suggested defect structures (domain walls, strings, and monopoles) to appear during the expansion and cooling of the early universe. The lack of such defects within the visible horizon of the universe mainly motivated inflationary Big Bang theories. W. H. Zurek pointed out that the same principles are relevant within the laboratory when a system obeying a second-order phase transition is cooled at finite rates into the low symmetry phase. Using a colloidal system, we visualize the Kibble–Zurek mechanism on single particle level and clarify its nature in the background of an established microscopic melting formalism.
Essential role of Orai1 store-operated calcium channels in lactation
Authors: Davis Felicity M. , Janoshazi Agnes , Janardhan Kyathanahalli S. , Steinckwich Natacha , D’Agostin Diane M. , Petranka John G. , Desai Pooja N. , Roberts-Thomson Sarah J. , Bird Gary S. , Tucker Deirdre K. , Fenton Suzanne E. , Feske Stefan , Monteith Gregory R. , Putney James W.
Published: April 2015

Significance

All mammals, from platypuses to humans, produce relatively immature offspring that are wholly dependent on their mother’s milk for their postnatal growth and development. However, the dynamic signaling and molecular mechanisms responsible for the transport of key constituents (e.g., calcium) into milk and for alveolar unit contraction and milk ejection are not fully understood. Using genetically modified mouse models, we demonstrate that the store-operated Ca
2+
channel Orai1 delivers over 50% of the calcium ions present in milk. We also reveal an unanticipated role of Orai1 as a master regulator of oxytocin-mediated alveolar unit contractility, milk ejection, and pup survival. These results provide a unique mechanistic insight into the fundamentally mammalian process of lactation.
Cellular inhibitor of apoptosis proteins prevent clearance of hepatitis B virus
Authors: Ebert Gregor , Preston Simon , Allison Cody , Cooney James , Toe Jesse G. , Stutz Michael D. , Ojaimi Samar , Scott Hamish W. , Baschuk Nikola , Nachbur Ueli , Torresi Joseph , Chin Ruth , Colledge Danielle , Li Xin , Warner Nadia , Revill Peter , Bowden Scott , Silke John , Begley C. Glenn , Pellegrini Marc
Published: April 2015

Significance

Hepatitis B virus (HBV) causes substantial morbidity and mortality. A large proportion of infected individuals controls infection but does not completely eradicate HBV DNA from the liver, and flares in hepatitis can be precipitated by immunosuppression. A proportion of individuals never controls infection, and these people are at substantial risk of developing liver failure and liver cancer. Current therapies are not effective at eliminating virus, and there is a major interest in developing functional cures for HBV infection. We identified host cell signaling molecules that can restrict the ability to eradicate infected cells. These molecules can be therapeutically targeted, and drugs that interfere with the function of these host cell proteins may be useful therapies to promote clearance of HBV infection.
Periodic retinoic acid–STRA8 signaling intersects with periodic germ-cell competencies to regulate spermatogenesis
Authors: Endo Tsutomu , Romer Katherine A. , Anderson Ericka L. , Baltus Andrew E. , de Rooij Dirk G. , Page David C.
Published: April 2015

Significance

As male sex cells mature into sperm, two pivotal transitions are spermatogonial differentiation (exit from the stem cell pool) and meiotic initiation. These transitions occur in physical proximity, with 8.6-d periodicity. We report that the gene
Stra8
, essential for meiotic initiation, also promotes (but is not required for) spermatogonial differentiation. Moreover, injected RA induces both transitions to occur precociously. We conclude that a periodic RA signal, acting instructively through the common target
Stra8
, coordinates these transitions. This RA signal intersects with two distinct windows of sex-cell competency, which both begin while RA levels are low; sex cells respond quickly to rising RA. These mechanisms help account for the elaborate organization of sperm production, and its prodigious output.
Sec17 can trigger fusion of
trans
-SNARE paired membranes without Sec18
Authors: Zick Michael , Orr Amy , Schwartz Matthew L. , Merz Alexey J. , Wickner William T.
Published: April 2015

Significance

Intracellular membrane trafficking relies on SNARE proteins from apposed membranes to form
trans
-complexes. Sec18 (
N
-ethylmaleimide–sensitive factor; NSF) and its cochaperone Sec17 (soluble NSF attachment protein; α-SNAP) disassemble
cis
-SNARE complexes, liberating SNAREs for
trans
-complex assembly. We now describe an additional function of Sec17, its ability to trigger the fusion of
trans
-SNARE paired membranes. We propose a model in which Sec17 oligomerizes on
trans
-SNARE complexes, inserting apolar loops into the adjacent membranes. This precisely localized membrane interaction may disturb the lipid bilayer, lowering the energy barrier that prevents the two membranes from merging, and thereby facilitate fusion.
Ndj1, a telomere-associated protein, regulates centrosome separation in budding yeast meiosis
Authors: Li Ping , Shao Yize , Jin Hui , Yu Hong-Guo
Published: April 2015

Yeast centrosomes (called spindle pole bodies [SPBs]) remain cohesive for hours during meiotic G2 when recombination takes place. In contrast, SPBs separate within minutes after duplication in vegetative cells. We report here that Ndj1, a previously known meiosis-specific telomere-associated protein, is required for protecting SPB cohesion. Ndj1 localizes to the SPB but dissociates from it ∼16 min before SPB separation. Without Ndj1, meiotic SPBs lost cohesion prematurely, whereas overproduction of Ndj1 delayed SPB separation. When produced ectopically in vegetative cells, Ndj1 caused SPB separation defects and cell lethality. Localization of Ndj1 to the SPB depended on the SUN domain protein Mps3, and removal of the N terminus of Mps3 allowed SPB separation and suppressed the lethality of NDJ1-expressing vegetative cells. Finally, we show that Ndj1 forms oligomeric complexes with Mps3, and that the Polo-like kinase Cdc5 regulates Ndj1 protein stability and SPB separation. These findings reveal the underlying mechanism that coordinates yeast centrosome dynamics with meiotic telomere movement and cell cycle progression.
Cell motion predicts human epidermal stemness
Authors: Nanba Daisuke , Toki Fujio , Tate Sota , Imai Matome , Matsushita Natsuki , Shiraishi Ken , Sayama Koji , Toki Hiroshi , Higashiyama Shigeki , Barrandon Yann
Published: April 2015

Image-based identification of cultured stem cells and noninvasive evaluation of their proliferative capacity advance cell therapy and stem cell research. Here we demonstrate that human keratinocyte stem cells can be identified in situ by analyzing cell motion during their cultivation. Modeling experiments suggested that the clonal type of cultured human clonogenic keratinocytes can be efficiently determined by analysis of early cell movement. Image analysis experiments demonstrated that keratinocyte stem cells indeed display a unique rotational movement that can be identified as early as the two-cell stage colony. We also demonstrate that α6 integrin is required for both rotational and collective cell motion. Our experiments provide, for the first time, strong evidence that cell motion and epidermal stemness are linked. We conclude that early identification of human keratinocyte stem cells by image analysis of cell movement is a valid parameter for quality control of cultured keratinocytes for transplantation.
TREM-2 promotes macrophage survival and lung disease after respiratory viral infection
Authors: Wu Kangyun , Byers Derek E. , Jin Xiaohua , Agapov Eugene , Alexander-Brett Jennifer , Patel Anand C. , Cella Marina , Gilfilan Susan , Colonna Marco , Kober Daniel L. , Brett Tom J. , Holtzman Michael J.
Published: April 2015

Viral infections and type 2 immune responses are thought to be critical for the development of chronic respiratory disease, but the link between these events needs to be better defined. Here, we study a mouse model in which infection with a mouse parainfluenza virus known as Sendai virus (SeV) leads to long-term activation of innate immune cells that drive IL-13–dependent lung disease. We find that chronic postviral disease (signified by formation of excess airway mucus and accumulation of M2-differentiating lung macrophages) requires macrophage expression of triggering receptor expressed on myeloid cells-2 (TREM-2). Analysis of mechanism shows that viral replication increases lung macrophage levels of intracellular and cell surface TREM-2, and this action prevents macrophage apoptosis that would otherwise occur during the acute illness (5–12 d after inoculation). However, the largest increases in TREM-2 levels are found as the soluble form (sTREM-2) long after clearance of infection (49 d after inoculation). At this time, IL-13 and the adapter protein DAP12 promote TREM-2 cleavage to sTREM-2 that is unexpectedly active in preventing macrophage apoptosis. The results thereby define an unprecedented mechanism for a feed-forward expansion of lung macrophages (with IL-13 production and consequent M2 differentiation) that further explains how acute infection leads to chronic inflammatory disease.
Fabrication of alumina filled hybrid buckypaper composites and their enhancement of microwave absorbing performance
Authors: Miao Hsin-Yuan , Liu Jih-Hsin , Saravanan L
Published: April 2015

Alumina (Al2O3)-filled multiwalled carbon nanotube buckypapers (BPs) with different Al2O3 loadings (5–50 wt%) were successfully synthesised. Structural and morphological analysis performed with x-ray diffraction and field-emission scanning electron microscopy, respectively, confirmed the presence of stable α-phase Al2O3 particles in the Al2O3-BP composites. The formation of flexible Al2O3-BP hybrid nanocomposites (5–15 wt%) was attributed to the strong interfacial polarisation and high conductivity; compared with pure Al2O3 and BP. The nanocomposites with optimised alumina loadings demonstrated enhanced microwave absorption (>90%) and a broader absorption bandwidth in the investigated high-frequency region.
Disseminated Mycobacterial Infection After International Medical Tourism
Authors: Kendall Brian A. , Barker Adam P. , Hadley Jason C. , Florell Scott R. , Winthrop Kevin L.
Published: April 2015

International travel for the purpose of receiving medical care is increasing. We report a case of disseminated mycobacterial infection after fetal stem cell infusion.
A deep, unusual over-contact binary system with high rate of mass transfer: LP Ursa Major
Authors: Liao Wen-Ping , Qian Sheng-Bang , Zhao Er-Gang , Li Lin-Jia
Published: April 2015

We observed the well-known unusual deep over-contact binary in 2012 and 2013. A new set of light curves and eight new observed times of light minima were derived. A total of 130 available CCD times of light minima were analyzed. The highest rate of long-term period increase in W UMa stars (+10.21 s century−1) was confirmed. The rapid period increase implies that the primary is accreting mass from the secondary at a high rate of $\skew4\dot{M} = 5.3 \times 10^{-6}\,M_{\odot }\:$yr−1. The asymmetric light curves (i.e., the O'Connell effect) were analyzed with the Wilson–Devinney Code. It was found that the spotted photometric solution with the third light is the best one for fitting the light curves. The main photometric results confirmed that LP UMa is an unusual W UMa system with a high mass ratio (q = 0.823 ± 0.003), deep-contact configuration (f = 66.6% ± 3.1%), and a temperature difference of Δ T = 700 K. The period increase in LP UMa may be a part of a long-period cyclic change because of the large third light contributions to the total system (61.52% in V, 61.39% in R, and 61.36% in I). All of these quite different properties make LP UMa a very interesting system to study. The possible evolutionary stage is also discussed.
Modelling nanoflares in active regions and implications for coronal heating mechanisms
Authors: Cargill P. J. , Warren H. P. , Bradshaw S. J.
Published: April 2015

Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500–2000 s, (ii) a weak ‘hot’ component (more than 10
6.6
 K) is present, and (iii) nanoflare energies may be as low as a few 10
23
ergs. These imply small heating events in a stressed coronal magnetic field, where the time between individual nanoflares on a strand is of order the cooling time. Modelling suggests that the observed properties are incompatible with nanoflare models that require long energy build-up (over 10 s of thousands of seconds) and with steady heating.
Relating magnetic reconnection to coronal heating
Authors: Longcope D. W. , Tarr L. A.
Published: April 2015

It is clear that the solar corona is being heated and that coronal magnetic fields undergo reconnection all the time. Here we attempt to show that these two facts are related—i.e. coronal reconnection generates heat. This attempt must address the fact that topological change of field lines does not automatically generate heat. We present one case of flux emergence where we have measured the rate of coronal magnetic reconnection and the rate of energy dissipation in the corona. The ratio of these two,

, is a current comparable to the amount of current expected to flow along the boundary separating the emerged flux from the pre-existing flux overlying it. We can generalize this relation to the overall corona in quiet Sun or in active regions. Doing so yields estimates for the contribution to coronal heating from magnetic reconnection. These estimated rates are comparable to the amount required to maintain the corona at its observed temperature.
Limnochorda pilosa gen. nov., sp. nov., a moderately thermophilic, facultatively anaerobic, pleomorphic bacterium and proposal of Limnochordaceae fam. nov., Limnochordales ord. nov. and Limnochordia classis nov. in the phylum Firmicutes
Authors: Watanabe Miho , Kojima Hisaya , Fukui Manabu
Published: April 2015

A novel facultatively anaerobic bacterium, strain HC45T, was isolated from sediment of a brackish meromictic lake in Japan, Lake Harutori. Cells were pleomorphic, and filamentous bodies were 5–100 μm in length. For growth, the optimum pH was 7.0 and the optimum temperature was 45–50 °C. The G+C content of the genomic DNA was 71 mol%. iso-C15 : 0and anteiso-C15 : 0were the major components in the cellular fatty acid profile. The predominant respiratory quinone was MK-7. Strain HC45Tshared very low 16S rRNA gene sequence similarity with cultivated strains ( ≤ 85 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was distantly related to members of the familySymbiobacteriaceaeand family XVIIIncertae Sedisin the classClostridia, and they formed a cluster separate from canonical species of the phylumFirmicutes. These results indicated that strain HC45Tshould not be placed in any existing class of the phylumFirmicutes. On the basis of phylogenetic and phenotypic characterization,Limnochorda pilosagen. nov., sp. nov. is proposed with HC45T( = NBRC 110152T = DSM 28787T) as the type strain, as the first representative of novel taxa,Limnochordalesord. nov.,Limnochordaceaefam. nov. inLimnochordiaclassis. nov.
A high-sensitivity phospho-switch triggered by Cdk1 governs chromosome morphogenesis during cell division
Authors: Robellet Xavier , Thattikota Yogitha , Wang Fang , Wee Tse-Luen , Pascariu Mirela , Shankar Sahana , Bonneil Éric , Brown Claire M. , D’Amours Damien
Published: April 2015

The initiation of chromosome morphogenesis marks the beginning of mitosis in all eukaryotic cells. Although many effectors of chromatin compaction have been reported, the nature and design of the essential trigger for global chromosome assembly remain unknown. Here we reveal the identity of the core mechanism responsible for chromosome morphogenesis in early mitosis. We show that the unique sensitivity of the chromosome condensation machinery for the kinase activity of Cdk1 acts as a major driving force for the compaction of chromatin at mitotic entry. This sensitivity is imparted by multisite phosphorylation of a conserved chromatin-binding sensor, the Smc4 protein. The multisite phosphorylation of this sensor integrates the activation state of Cdk1 with the dynamic binding of the condensation machinery to chromatin. Abrogation of this event leads to chromosome segregation defects and lethality, while moderate reduction reveals the existence of a novel chromatin transition state specific to mitosis, the intertwist configuration. Collectively, our results identify the mechanistic basis governing chromosome morphogenesis in early mitosis and how distinct chromatin compaction states can be established via specific thresholds of Cdk1 kinase activity.
Structural basis for corepressor assembly by the orphan nuclear receptor TLX
Authors: Zhi Xiaoyong , Zhou X. Edward , He Yuanzheng , Searose-Xu Kelvin , Zhang Chun-Li , Tsai Chih-Cheng , Melcher Karsten , Xu H. Eric
Published: April 2015

The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Here we report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. In these structures, TLX adopts an autorepressed conformation in which its helix H12 occupies the coactivator-binding groove. Unexpectedly, H12 in this autorepressed conformation forms a novel binding pocket with residues from helix H3 that accommodates a short helix formed by the conserved ALXXLXXY motif of the Atro box. Mutations that weaken the TLX–Atrophin interaction compromise the repressive activity of TLX, demonstrating that this interaction is required for Atrophin to confer repressor activity to TLX. Moreover, the autorepressed conformation is conserved in the repressor class of orphan nuclear receptors, and mutations of corresponding residues in other members of this class of receptors diminish their repressor activities. Together, our results establish the functional conservation of the autorepressed conformation and define a key sequence motif in the Atro box that is essential for TLX-mediated repression.
Cas9 function and host genome sampling in Type II-A CRISPR–Cas adaptation
Authors: Wei Yunzhou , Terns Rebecca M. , Terns Michael P.
Published: April 2015

To acquire the ability to recognize and destroy virus and plasmid invaders, prokaryotic CRISPR–Cas systems capture fragments of DNA within the host CRISPR locus. Our results indicate that the process of adaptation by a Type II-A CRISPR–Cas system in Streptococcus thermophilus requires Cas1, Cas2, and Csn2. Surprisingly, we found that Cas9, previously identified as the nuclease responsible for ultimate invader destruction, is also essential for adaptation. Cas9 nuclease activity is dispensable for adaptation. In addition, our studies revealed extensive, unbiased acquisition of the self-targeting host genome sequence by the CRISPR–Cas system that is masked in the presence of active target destruction.
Simultaneous multiplexed materials characterization using a high-precision hard X-ray micro-slit array
Authors: Zhang Fan , Allen Andrew J. , Levine Lyle E. , Mancini Derrick C. , Ilavsky Jan
Published: April 2015

The needs both for increased experimental throughput and forin operandocharacterization of functional materials under increasingly realistic experimental conditions have emerged as major challenges across the whole of crystallography. A novel measurement scheme that allows multiplexed simultaneous measurements from multiple nearby sample volumes is presented. This new approach enables better measurement statistics or direct probing of heterogeneous structure, dynamics or elemental composition. To illustrate, the submicrometer precision that optical lithography provides has been exploited to create a multiplexed form of ultra-small-angle scattering based X-ray photon correlation spectroscopy (USAXS-XPCS) using micro-slit arrays fabricated by photolithography. Multiplexed USAXS-XPCS is applied to follow the equilibrium dynamics of a simple colloidal suspension. While the dependence of the relaxation time on momentum transfer, and its relationship with the diffusion constant and the static structure factor, follow previous findings, this measurements-in-parallel approach reduces the statistical uncertainties of this photon-starved technique to below those associated with the instrument resolution. More importantly, we note the potential of the multiplexed scheme to elucidate the response of different components of a heterogeneous sample underidenticalexperimental conditions insimultaneousmeasurements. In the context of the X-ray synchrotron community, this scheme is, in principle, applicable to all in-line synchrotron techniques. Indeed, it has the potential to open a new paradigm forin operandocharacterization of heterogeneous functional materials, a situation that will be even further enhanced by the ongoing development of multi-bend achromat storage ring designs as the next evolution of large-scale X-ray synchrotron facilities around the world.
Crystal structure of di-μ-chlorido-bis[dichloridobis(methanol-κO)iridium(III)] dihydrate: a surprisingly simple chloridoiridium(III) dinuclear complex with methanol ligands
Authors: Merola Joseph S. , Slebodnick Carla , Houser Christopher
Published: April 2015

The reaction between IrCl3·xH2O in methanol led to the formation of small amounts of the title compound, [Ir2Cl6(CH3OH)4]·2H2O, which consists of two IrCl4O2octahedra sharing an edgeviachloride bridges. The molecule lies across an inversion center. Each octahedron can be envisioned as being comprised of four chloride ligands in the equatorial plane with methanol ligands in the axial positions. A lattice water molecule is strongly hydrogen-bonded to the coordinating methanol ligands and weak interactions with coordinating chloride ligands lead to the formation of a three-dimensional network. This is a surprising structure given that, while many reactions of iridium chloride hydrate are carried out in alcoholic solvents, especially methanol and ethanol, this is the first structure of a chloridoiridium compound with only methanol ligands.
Crystal structure of 4-(2-azidophenyl)-5-benzoyl-2-(1H-indol-3-yl)-1H-pyrrole-3-carbonitrile
Authors: Vimala G. , Raja J. Kamal , Naaz Y. Amina , Preumal P. T. , SubbiahPandi A.
Published: April 2015

In the title compound, C26H16N6O, the dihedral angles between the central pyrrole ring and the pendant indole ring system (r.m.s. deviation = 0.027 Å) and the azide-bearing benzene ring are 37.56 (8) and 51.62 (11)°, respectively. The azide group is almost coplanar with its attached benzene ring [C—C—N—N = 3.8 (3)°]. The benzoyl benzene ring is disordered over two orientations twisted with respect to each other by 9.29 (8)° in a 0.514 (2):0.486 (2) ratio. In the crystal, inversion dimers linked by pairs of Np—H...O (p = pyrrole) hydrogen bonds generateR22(10) loops. A second inversion dimer arises from a pair of Ni—H...Nc(i = indole and c = cyanide) hydrogen bonds, which generates anR22(16) loop. Together, the hydrogen bonds lead to [011] chains in the crystal.
Crystal structures of 1-(4-chlorophenyl)-2-(diphenylphosphoryl)ethan-1-one and 1-(diphenylphosphoryl)-3,3-dimethylbutan-2-one
Authors: Leach Erin G. , Kulesza Alyssa A. , Staples Richard J. , Biros Shannon M.
Published: April 2015

The title compounds, C20H16ClO2P, (I), and C18H21O2P, (II), were synthesizedviaan Arbuzov reaction between an α-bromoketone and isopropoxydiphenylphosphane. In the crystals of both compounds, molecules are linkedviabifurcated C—H...(O,O) hydrogen bonds, forming chains propagating along [100] for (I) and along [010] for (II). The chains are linkedviaC—H...π interactions, leading to the formation of sheets lying parallel to (010) for (I) and (001) for (II). The absolute structure of compound (II) was determined by resonant scattering [Flack parameter = 0.088 (14)].
Hydrothermal synthesis and crystal structure of a new lanthanum(III) coordination polymer with fumaric acid
Authors: Anana Hayet , Trifa Chahrazed , Bouacida Sofiane , Boudaren Chaouki , Merazig Hocine
Published: April 2015

The title compound, poly[diaquatris(μ4-but-2-enedioato)(μ2-but-2-enedioic acid)dilanthanum(III)], [La2(C4H2O4)3(C4H4O4)(H2O)2]n, was synthesized by the reaction of lanthanum chloride pentahydrate with fumaric acid under hydrothermal conditions. The asymmetric unit comprises an LaIIIcation, one and a half fumarate dianions (L2−), one a half-molecule of fumaric acid (H2L) and one coordinated water molecule. Each LaIIIcation has the same nine-coordinate environment and is surrounded by eight O atoms from seven distinct fumarate moieties, including one protonated fumarate unit and one water molecule in a distorted tricapped trigonal–prismatic environment. The LaO8(H2O) polyhedra centres are edge-shared through three carboxylate bridges of the fumarate ligand, forming chains in three dimensions to construct the MOF. The crystal structure is stabilized by O—H...O hydrogen-bond interactions between the coordinated water molecule and the carboxylate O atoms, and also between oxygen atoms of fumaric acid
Cystal structre of 5-hydroxy-2-nitrobenzaldehyde
Authors: Bano Huma , Yousuf Sammer
Published: April 2015

In the title compound, C7H5NO4, the nitro group and the aldehyde group are inclined to the benzene ring by 16.6 (3) and 15.6 (3)°, respectively. In the crystal, molecules are linkedviaO—H...O hydrogen bonds, forming chains along [100]. The chains are linked by C—H...O hydrogen bonds, forming a three-dimensional structure.
Crystal structure of bis[4-(1H-pyrrol-1-yl)phenyl] ferrocene-1,1′-dicarboxylate: a potential chemotherapeutic drug
Authors: Pérez Wanda I. , Rheingold Arnold L. , Meléndez Enrique
Published: April 2015

The title iron(II) complex, [Fe(C16H12NO2)2], crystallizes in the orthorhombic space groupPbcawith the Fe2+cation positioned on an inversion center. The cyclopentadienyl (Cp) rings adopt ananticonformation in contrast with other substituted ferrocenes in which the Cp rings appear in a nearly eclipsed conformation. The Cp and the aromatic rings are positioned out of the plane, with a twist angle of 70.20 (12)°, and the C(Cp)—C(CO) bond length is shorter than a typical C—C single bond, which suggests a partial double-bond character and delocalization with the Cp π system. The structure of the complex is compared to other functionalized ferrocenes synthesized in our laboratory.
Crystal structure of bis[trans-(1,4,8,11-tetraazacyclotetradecane-κ4N)bis(thiocyanato-κN)chromium(III)] tetrachloridozincate from synchrotron data
Authors: Moon Dohyun , Ryoo Keon Sang , Choi Jong-Ha
Published: April 2015

The structure of the title compound, [Cr(NCS)2(cyclam)]2[ZnCl4] (cyclam = 1,4,8,11-tetraazacyclotetradecane, C10H24N4), has been determined from synchrotron data. The asymmetric unit contains two independent halves of the CrIIIcomplex cations and half of a tetrachloridozincate anion. In each complex cation, the CrIIIatom is coordinated by the four N atoms of the cyclam ligand in the equatorial plane and by two N-bound NCS−anions in atransaxial arrangement, displaying a distorted octahedral geometry with crystallographic inversion symmetry. The mean Cr—N(cyclam) and Cr—N(NCS) bond lengths are 2.065 (4) and 1.995 (6) Å, respectively. The macrocyclic cyclam moieties adopt centrosymmetrictrans-III configurations with six- and five-membered chelate rings in chair andgaucheconfigurations, respectively. The [ZnCl4]2−anion, which lies about a twofold rotation axis, has a slightly distorted tetrahedral geometry. The crystal packing is stabilized by hydrogen-bonding interactions between the N—H groups of the cyclam ligands, the S atoms of the NCS−groups and the Cl−ligands of the anion.