bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probing the symmetry of the potential of localized surface plasmon resonances with phase-shaped electron beams
Authors: Guzzinati Giulio , Béché Armand , Lourenço-Martins Hugo , Martin Jérôme , Kociak Mathieu , Verbeeck Jo 
Published: April 2017

AbstractPlasmonics, the science and technology of the interaction of light with metallic objects, is fundamentally changing the way we can detect, generate and manipulate light. Although the field is progressing swiftly, thanks to the availability of nanoscale manufacturing and analysis methods, fundamental properties such as the plasmonic excitations’ symmetries cannot be accessed directly, leading to a partial, sometimes incorrect, understanding of their properties. Here we overcome this limitation by deliberately shaping the wave function of an electron beam to match a plasmonic excitations’ symmetry in a modified transmission electron microscope. We show experimentally and theoretically that this offers selective detection of specific plasmon modes within metallic nanoparticles, while excluding modes with other symmetries. This method resembles the widespread use of polarized light for the selective excitation of plasmon modes with the advantage of locally probing the response of individual plasmonic objects and a far wider range of symmetry selection criteria.
Intercalant-independent transition temperature in superconducting black phosphorus
Authors: Zhang R. , Waters J. , Geim A. K. , Grigorieva I. V. 
Published: April 2017

AbstractResearch on black phosphorus has been experiencing a renaissance over the last years, after the demonstration that few-layer crystals exhibit high carrier mobility and a thickness-dependent bandgap. Black phosphorus is also known to be a superconductor under high pressure exceeding 10 GPa. The superconductivity is due to a structural transformation into another allotrope and accompanied by a semiconductor-metal transition. No superconductivity could be achieved for black phosphorus in its normal orthorhombic form, despite several reported attempts. Here we describe its intercalation by several alkali metals (Li, K, Rb and Cs) and alkali-earth Ca. All the intercalated compounds are found to be superconducting, exhibiting the same (within experimental accuracy) critical temperature of 3.8±0.1 K and practically identical characteristics in the superconducting state. Such universal superconductivity, independent of the chemical composition, is highly unusual. We attribute it to intrinsic superconductivity of heavily doped individual phosphorene layers, while the intercalated layers of metal atoms play mostly a role of charge reservoirs.
Formal Definitions of Unbounded Evolution and Innovation Reveal Universal Mechanisms for Open-Ended Evolution in Dynamical Systems
Authors: Adams Alyssa , Zenil Hector , Davies Paul C. W. , Walker Sara Imari 
Published: April 2017

AbstractOpen-ended evolution (OEE) is relevant to a variety of biological, artificial and technological systems, but has been challenging to reproducein silico. Most theoretical efforts focus on key aspects of open-ended evolution as it appears in biology. We recast the problem as a more general one in dynamical systems theory, providing simple criteria for open-ended evolution based on two hallmark features: unbounded evolution and innovation. We define unbounded evolution as patterns that are non-repeating within the expected Poincare recurrence time of an isolated system, and innovation as trajectories not observed in isolated systems. As a case study, we implement novel variants of cellular automata (CA) where the update rules are allowed to vary with time in three alternative ways. Each is capable of generating conditions for open-ended evolution, but vary in their ability to do so. We find that state-dependent dynamics, regarded as a hallmark of life, statistically out-performs other candidate mechanisms, and is the only mechanism to produce open-ended evolution in a scalable manner, essential to the notion of ongoing evolution. This analysis suggests a new framework for unifying mechanisms for generating OEE with features distinctive to life and its artifacts, with broad applicability to biological and artificial systems.
Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration
Authors: Jäckel David , Bakkum Douglas J. , Russell Thomas L. , Müller Jan , Radivojevic Milos , Frey Urs , Franke Felix , Hierlemann Andreas 
Published: April 2017

AbstractWe present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11’000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron.
The prognostic significance of Cdc6 and Cdt1 in breast cancer
Authors: Mahadevappa Ravikiran , Neves Henrique , Yuen Shun Ming , Bai Yuchen , McCrudden Cian M. , Yuen Hiu Fung , Wen Qing , Zhang Shu Dong , Kwok Hang Fai 
Published: April 2017

AbstractDNA replication is a critical step in cell proliferation. Overexpression of MCM2-7 genes correlated with poor prognosis in breast cancer patients. However, the roles of Cdc6 and Cdt1, which work with MCMs to regulate DNA replication, in breast cancers are largely unknown. In the present study, we have shown that the expression levels of Cdc6 and Cdt1 were both significantly correlated with an increasing number of MCM2-7 genes overexpression. Both Cdc6 and Cdt1, when expressed in a high level, alone or in combination, were significantly associated with poorer survival in the breast cancer patient cohort (n = 1441). In line with this finding, the expression of Cdc6 and Cdt1 was upregulated in breast cancer cells compared to normal breast epithelial cells. Expression of Cdc6 and Cdt1 was significantly higher in ER negative breast cancer, and was suppressed when ER signalling was inhibited either by tamoxifen in vitro or letrozole in human subjects. Importantly, breast cancer patients who responded to letrozole expressed significantly lower Cdc6 than those patients who did not respond. Our results suggest that Cdc6 is a potential prognostic marker and therapeutic target in breast cancer patients.
Poly-protein G-expressing bacteria enhance the sensitivity of immunoassays
Authors: Hao Wen-Rui , Chen Michael , Chen Yi-Jou , Su Yu-Cheng , Cheng Chiu-Min , Hsueh Hsiang-Yin , Kao An-Pei , Hsieh Yuan-Chin , Chang Johny , Tseng Ming-Yang , Chuang Kuo-Hsiang 
Published: April 2017

AbstractThe sensitivities of solid-phase immunoassays are limited by the quantity of detection antibodies bound to their antigens on the solid phase. Here, we developed a poly-protein G-expressing bacterium as an antibody-trapping microparticle to enhance the signals of immunoassays by increasing the accumulation of detection antibodies on the given antigen. Eight tandemly repeated fragment crystallisable (Fc) binding domains of protein G were stably expressed on the surface of Escherichia coli BL21 cells (termed BL21/8G). BL21/8G cells showed a higher avidity for trapping antibodies on their surface than monomeric protein G-expressing BL21 (BL21/1G) cells did. In the sandwich enzyme-linked immunosorbent assay (ELISA), simply mixing the detection antibody with BL21/8G provided a detection limit of 6 pg/mL for human interferon-α (IFN-α) and a limit of 30 pg/mL for polyethylene glycol (PEG)-conjugated IFN-α (Pegasys), which are better than that of the traditional ELISA (30 pg/mL for IFN-α and 100 pg/mL for Pegasys). Moreover, the sensitivity of the Western blot for low-abundance Pegasys (0.4 ng/well) was increased by 25 folds upon mixing of an anti-PEG antibody with BL21/8G cells. By simply being mixed with a detection antibody, the poly-protein G-expressing bacteria can provide a new method to sensitively detect low-abundance target molecules in solid-phase immunoassays.
Low-noise time-resolved optical sensing of electromagnetic pulses from petawatt laser-matter interactions
Authors: Robinson T. S. , Consoli F. , Giltrap S. , Eardley S. J. , Hicks G. S. , Ditter E. J. , Ettlinger O. , Stuart N. H. , Notley M. , De Angelis R. , Najmudin Z. , Smith R. A. 
Published: April 2017

AbstractWe report on the development and deployment of an optical diagnostic for single-shot measurement of the electric-field components of electromagnetic pulses from high-intensity laser-matter interactions in a high-noise environment. The electro-optic Pockels effect in KDP crystals was used to measure transient electric fields using a geometry easily modifiable for magnetic field detection via Faraday rotation. Using dielectric sensors and an optical fibre-based readout ensures minimal field perturbations compared to conductive probes and greatly limits unwanted electrical pickup between probe and recording system. The device was tested at the Vulcan Petawatt facility with 1020 W cm−2 peak intensities, the first time such a diagnostic has been used in this regime. The probe crystals were located ~1.25 m from target and did not require direct view of the source plasma. The measured signals compare favourably with previously reported studies from Vulcan, in terms of the maximum measured intra-crystal field of 10.9 kV/m, signal duration and detected frequency content which was found to match the interaction chamber’s horizontal-plane fundamental harmonics of 76 and 101 MHz. Methods for improving the diagnostic for future use are also discussed in detail. Orthogonal optical probes offer a low-noise alternative for direct simultaneous measurement of each vector field component.
Application of high resolution melting assay (HRM) to study temperature-dependent intraspecific competition in a pathogenic bacterium
Authors: Ashrafi Roghaieh , Bruneaux Matthieu , Sundberg Lotta-Riina , Pulkkinen Katja , Ketola Tarmo 
Published: April 2017

AbstractStudies on species’ responses to climate change have focused largely on the direct effect of abiotic factors and in particular temperature, neglecting the effects of biotic interactions in determining the outcome of climate change projections. Many microbes rely on strong interference competition; hence the fitness of many pathogenic bacteria could be a function of both their growth properties and intraspecific competition. However, due to technical challenges in distinguishing and tracking individual strains, experimental evidence on intraspecific competition has been limited so far. Here, we developed a robust application of the high-resolution melting (HRM) assay to study head-to-head competition between mixed genotype co-cultures of a waterborne bacterial pathogen of fish, Flavobacterium columnare, at two different temperatures. We found that competition outcome in liquid cultures seemed to be well predicted by growth yield of isolated strains, but was mostly inconsistent with interference competition results measured in inhibition tests on solid agar, especially as no growth inhibition between strain pairs was detected at the higher temperature. These results suggest that, for a given temperature, the factors driving competition outcome differ between liquid and solid environments.
C1QBP suppresses cell adhesion and metastasis of renal carcinoma cells
Authors: Wang Yong , Fu Donghe , Su Jing , Chen Yajing , Qi Can , Sun Yin , Niu Yuanjie , Zhang Ning , Yue Dan 
Published: April 2017

AbstractComplement component 1q subcomponent binding protein (C1QBP) is a ubiquitously expressed cellular protein and can be upregulated or activated in a variety of malignant tumors, including those from thyroid, colon and breast, but its role remains unclear in renal cell carcinoma (RCC). In this study, C1QBP knockdown in RCC cell influenced expression of multiple genes associated with cell adhesion, among which L1 cell adhesion molecule (L1CAM) was significantly higher upon a reduction of C1QBP. In turn, cell adhesion and invasion abilities were significantly increased with increased metastasis to lung and liver in vivo. C1QBP may regulate RCC cell adhesion and invasion through influencing the p-GSK3/β-Catenin/L1CAM expression. Over all, our study demonstrated that C1QBP could regulate RCC metastasis by regulating the GSK3/β-Catenin/L1CAM signaling pathway.
Transcription Factor Antagonism Controls Enteroendocrine Cell Specification from Intestinal Stem Cells
Authors: Li Yumei , Pang Zhimin , Huang Huanwei , Wang Chenhui , Cai Tao , Xi Rongwen 
Published: April 2017

AbstractThe balanced maintenance and differentiation of local stem cells is required for Homeostatic renewal of tissues. In the Drosophila midgut, the transcription factor Escargot (Esg) maintains undifferentiated states in intestinal stem cells, whereas the transcription factors Scute (Sc) and Prospero (Pros) promote enteroendocrine cell specification. However, the mechanism through which Esg and Sc/Pros coordinately regulate stem cell differentiation is unknown. Here, by combining chromatin immunoprecipitation analysis with genetic studies, we show that both Esg and Sc bind to a common promoter region of pros. Moreover, antagonistic activity between Esg and Sc controls the expression status of Pros in stem cells, thereby, specifying whether stem cells remain undifferentiated or commit to enteroendocrine cell differentiation. Our study therefore reveals transcription factor antagonism between Esg and Sc as a novel mechanism that underlies fate specification from intestinal stem cells in Drosophila.
The yeast osmostress response is carbon source dependent
Authors: Babazadeh Roja , Lahtvee Petri-Jaan , Adiels Caroline B. , Goksör Mattias , Nielsen Jens B. , Hohmann Stefan 
Published: April 2017

AbstractAdaptation to altered osmotic conditions is a fundamental property of living cells and has been studied in detail in the yeast Saccharomyces cerevisiae. Yeast cells accumulate glycerol as compatible solute, controlled at different levels by the High Osmolarity Glycerol (HOG) response pathway. Up to now, essentially all osmostress studies in yeast have been performed with glucose as carbon and energy source, which is metabolised by glycolysis with glycerol as a by-product. Here we investigated the response of yeast to osmotic stress when yeast is respiring ethanol as carbon and energy source. Remarkably, yeast cells do not accumulate glycerol under these conditions and it appears that trehalose may partly take over the role as compatible solute. The HOG pathway is activated in very much the same way as during growth on glucose and is also required for osmotic adaptation. Slower volume recovery was observed in ethanol-grown cells as compared to glucose-grown cells. Dependence on key regulators as well as the global gene expression profile were similar in many ways to those previously observed in glucose-grown cells. However, there are indications that cells re-arrange redox-metabolism when respiration is hampered under osmostress, a feature that could not be observed in glucose-grown cells.
Nanometre-scale 3D defects in Cr2AlC thin films
Authors: Chen Y. T. , Music D. , Shang L. , Mayer J. , Schneider J. M. 
Published: April 2017

AbstractMAX-phase Cr2AlC containing thin films were synthesized by magnetron sputtering in an industrial system. Nanometre-scale 3D defects are observed near the boundary between regions of Cr2AlC and of the disordered solid solution (CrAl)xCy. Shrinkage of the Cr-Cr interplanar distance and elongation of the Cr-Al distance in the vicinity of the defects are detected using transmission electron microscopy. The here observed deformation surrounding the defects was described using density functional theory by comparing the DOS of bulk Cr2AlC with the DOS of a strained and unstrained Cr2AlC(0001) surface. From the partial density of states analysis, it can be learned that Cr-C bonds are stronger than Cr-Al bonds in bulk Cr2AlC. Upon Cr2AlC(0001) surface formation, both bonds are weakened. While the Cr-C bonds recover their bulk strength as Cr2AlC(0001) is strained, the Cr-Al bonds experience only a partial recovery, still being weaker than their bulk counterparts. Hence, the strain induced bond strengthening in Cr2AlC(0001) is larger for Cr d – C p bonds than for Cr d – Al p bonds. The here observed changes in bonding due to the formation of a strained surface are consistent with the experimentally observed elongation of the Cr-Al distance in the vicinity of nm-scale 3D defects in Cr2AlC thin films.
Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope
Authors: André M. , Caballé A. , van der Schaar M. , Solsona A. , Houégnigan L. , Zaugg S. , Sánchez A. M. , Castell J. V. , Solé M. , Vila F. , Djokic D. , Adrián-Martínez S. , Albert A. , Anghinolfi M. , Anton G. , Ardid M. , Aubert J.-J. , Avgitas T. , Baret B. , Barrios-Martí J. , Basa S. , Bertin V. , Biagi S. , Bormuth R. , Bouwhuis M. C. , Bruijn R. , Brunner J. , Busto J. , Capone A. , Caramete L. , Carr J. , Celli S. , Chiarusi T. , Circella M. , Coleiro A. , Coniglione R. , Costantini H. , Coyle P. , Creusot A. , Deschamps A. , De Bonis G. , Distefano C. , Di Palma I. , Donzaud C. , Dornic D. , Drouhin D. , Eberl T. , El Bojaddaini I. , Elsässer D. , Enzenhöfer A. , Fehn K. , Felis I. , Fusco L. A. , Galatà S. , Gay P. , Geißelsöder S. , Geyer K. , Giordano V. , Gleixner A. , Glotin H. , Gracia-Ruiz R. , Graf K. , Hallmann S. , van Haren H. , Heijboer A. J. , Hello Y. , Hernandez-Rey J. J. , Hößl J. , Hofestädt J. , Hugon C. , Illuminati G. , James C. W. , de Jong M. , Jongen M. , Kadler M. , Kalekin O. , Katz U. , Kießling D. , Kouchner A. , Kreter M. , Kreykenbohm I. , Kulikovskiy V. , Lachaud C. , Lahmann R. , Lefèvre D. , Leonora E. , Loucatos S. , Marcelin M. , Margiotta A. , Marinelli A. , Martínez-Mora J. A. , Mathieu A. , Melis K. , Michael T. , Migliozzi P. , Moussa A. , Mueller C. , Nezri E. , Păvălaş G. E. , Pellegrino C. , Perrina C. , Piattelli P. , Popa V. , Pradier T. , Racca C. , Riccobene G. , Roensch K. , Saldaña M. , Samtleben D. F. E. , Sanguineti M. , Sapienza P. , Schnabel J. , Schüssler F. , Seitz T. , Sieger C. , Spurio M. , Stolarczyk Th. , Sánchez-Losa A. , Taiuti M. , Trovato A. , Tselengidou M. , Turpin D. , Tönnis C. , Vallage B. , Vallée C. , Van Elewyck V. , Vivolo D. , Wagner S. , Wilms J. , Zornoza J. D. , Zuñiga J. 
Published: April 2017

AbstractDespite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems.
Molecular evolutionary mechanisms driving functional diversification of α-glucosidase in Lepidoptera
Authors: Li Xiaotong , Shi Liangen , Zhou Yanyan , Xie Hongqing , Dai Xiangping , Li Rongqiao , Chen Yuyin , Wang Huabing 
Published: April 2017

AbstractThe digestive tract of lepidopteran insects is unique given its highly alkaline pH. The adaptive plasticity of digestive enzymes in this environment is crucial to the highly-efficient nutritional absorption in Lepidoptera. However, little is known about the molecular adaptation of digestive enzymes to this environment. Here, we show that lepidopteran α-glucosidase, a pivotal digestive enzyme, diverged into sucrose hydrolase (SUH) and other maltase subfamilies. SUH, which is specific for sucrose, was only detected in Lepidoptera. It suggests that lepidopteran insects have evolved an enhanced ability to hydrolyse sucrose, their major energy source. Gene duplications and exon-shuffling produced multiple copies of α-glucosidase in different microsyntenic regions. Furthermore, SUH showed significant functional divergence (FD) compared with maltase, which was affected by positive selection at specific lineages and codons. Nine sites, which were involved in both FD and positive selection, were located around the ligand-binding groove of SUH. These sites could be responsible for the ligand-binding preference and hydrolytic specificity of SUH for sucrose, and contribute to its conformational stability. Overall, our study demonstrated that positive selection is an important evolutionary force for the adaptive diversification of α-glucosidase, and for the exclusive presence of membrane-associated SUHs in the unique lepidopteran digestive tract.
Impact of metric and sample size on determining malaria hotspot boundaries
Authors: Stresman Gillian H. , Giorgi Emanuele , Baidjoe Amrish , Knight Phil , Odongo Wycliffe , Owaga Chrispin , Shagari Shehu , Makori Euniah , Stevenson Jennifer , Drakeley Chris , Cox Jonathan , Bousema Teun , Diggle Peter J. 
Published: April 2017

AbstractThe spatial heterogeneity of malaria suggests that interventions may be targeted for maximum impact. It is unclear to what extent different metrics lead to consistent delineation of hotspot boundaries. Using data from a large community-based malaria survey in the western Kenyan highlands, we assessed the agreement between a model-based geostatistical (MBG) approach to detect hotspots using Plasmodium falciparum parasite prevalence and serological evidence for exposure. Malaria transmission was widespread and highly heterogeneous with one third of the total population living in hotspots regardless of metric tested. Moderate agreement (Kappa = 0.424) was observed between hotspots defined based on parasite prevalence by polymerase chain reaction (PCR)- and the prevalence of antibodies to two P. falciparum antigens (MSP-1, AMA-1). While numerous biologically plausible hotspots were identified, their detection strongly relied on the proportion of the population sampled. When only 3% of the population was sampled, no PCR derived hotspots were reliably detected and at least 21% of the population was needed for reliable results. Similar results were observed for hotspots of seroprevalence. Hotspot boundaries are driven by the malaria diagnostic and sample size used to inform the model. These findings warn against the simplistic use of spatial analysis on available data to target malaria interventions in areas where hotspot boundaries are uncertain.