819 research outputs found
Highly stretchable and sensitive self-powered sensors based on the N-Type thermoelectric effect of polyurethane/Na_{x}(Ni-ett)_{n}/graphene oxide composites
The development of stretchable organic thermoelectric materials is prompted by fast evolving application fields like flexible electronic devices, soft robotics, health monitoring and internet-of-things. Stretchability in thermoelectric materials is usually obtained by using an insulating elastomer, either as a substrate or as a matrix in a blend or composite, which, unfortunately, leads to a compromise in thermoelectric performance. Herein, a potential solution is reported exploiting the addition of graphene oxide as a secondary (nano)filler in a polyurethane/poly nickel-ethenetetrathiolates film. Compared with traditional binary blends, our ternary composite shows an increased electrical conductivity (4 times), air-stability (âź20 times after 3 months), and stretchability (38% increase in strain at break). With a gauge factor (GF) of âź58, this new composite film shows high sensitivity to tensile strain. Thanks to its Seebeck coefficient of âź â40 ÎźV K^{â1}, the composite film can generate a thermopower of âź0.25 pW when subjected to a small temperature difference (30 °C), which could be exploited by self-powered strain sensors. Therefore, the ternary polyurethane/poly nickel-ethenetetrathiolates/graphene oxide composite film can work as a stretchable strain sensor, providing a strategy to reconcile the compromise between thermoelectric performance and stretchability
Flexible and Stretchable Self-Powered Multi-Sensors Based on the N-Type Thermoelectric Response of Polyurethane/Na-x(Ni-ett)(n) Composites
Flexible and stretchable electronic devices have a broad range of potential uses, from biomedicine, soft robotics, and health monitoring to the internetâofâthings. Unfortunately, finding a robust and reliable power source remains challenging, particularly in offâtheâgrid and maintenanceâfree applications. A soughtâafter development overcome this challenge is the development of autonomous, selfâpowered devices. A potential solution is reported exploiting a promising nâtype thermoelectric compound, poly nickelâethenetetrathiolates (Na_{x}(Niâett)_{n}). Highly stretchable nâtype composite films are obtained by combining Nax(Niâett)n with commercial polyurethane (Lycra). As high as 50 wt% Na_{x}(Niâett)_{n} content composite film can withstand deformations of â500% and show conductivities of â10^{-2} S cm^{-1} and Seebeck coefficients of approx. â40 ÂľV K^{-1}. These novel materials can be easily synthesized on a large scale with continuous processes. When subjected to a small temperature difference (<20 °C), the films generate sufficient thermopower to be used for sensing strain (gauge factor â20) and visible light (sensitivity factor â36% (kW m^{-2})^{-1}), independent of humidity (sensitivity factor â0.1 (%RH)^{-1}. As a proofâofâconcept, a wearable selfâpowered sensor is demonstrated by using nâtype Na_{x}(Niâett)_{n}/Lycra and PEDOT:PSS/Lycra elements, connected in series by hot pressing, without employing any metal connections, hence preserving good mechanical ductility and ease of processing
Voice cues are used in a similar way by blind and sighted adults when assessing womenâs body size
Humansâ ability to gauge another personâs body size from their voice alone may serve multiple functions ranging from threat assessment to speaker normalization. However, how this ability is acquired remains unknown. In two experiments we tested whether sighted, congenitally blind and late blind adults could accurately judge the relative heights of women from paired voice stimuli, and importantly, whether errors in size estimation varied with task difficulty across groups. Both blind (n = 56) and sighted (n = 61) listeners correctly judged womenâs relative heights on approximately 70% of low difficulty trials, corroborating previous findings for judging menâs heights. However, accuracy dropped to chance levels for intermediate difficulty trials and to 25% for high difficulty trials, regardless of the listenerâs sightedness, duration of vision loss, sex, or age. Thus, blind adults estimated womenâs height with the same degree of accuracy, but also the same pattern of errors, as did sighted controls. Our findings provide further evidence that visual experience is not necessary for accurate body size estimation. Rather, both blind and sighted listeners appear to follow a general rule, mapping low auditory frequencies to largeness across a range of contexts. This sound-size mapping emerges without visual experience, and is likely very important for humans
MicroRNAs Up-Regulated by CagA of Helicobacter pylori Induce Intestinal Metaplasia of Gastric Epithelial Cells
CagA of Helicobacter pylori is a bacterium-derived oncogenic protein closely associated with the development of gastric cancers. MicroRNAs (miRNAs) are a class of widespread non-coding RNAs, many of which are involved in cell growth, cell differentiation and tumorigenesis. The relationship between CagA protein and miRNAs is unclear. Using mammalian miRNA profile microarrays, we found that miRNA-584 and miRNA-1290 expression was up-regulated in CagA-transformed cells, miRNA-1290 was up-regulated in an Erk1/2-dependent manner, and miRNA-584 was activated by NF-ÎşB. miRNA-584 sustained Erk1/2 activities through inhibition of PPP2a activities, and miRNA-1290 activated NF-ÎşB by knockdown of NKRF. Foxa1 was revealed to be an important target of miRNA-584 and miRNA-1290. Knockdown of Foxa1 promoted the epithelial-mesenchymal transition significantly. Overexpression of miRNA-584 and miRNA-1290 induced intestinal metaplasia of gastric epithelial cells in knock-in mice. These results indicate that miRNA-584 and miRNA-1290 interfere with cell differentiation and remodel the tissues. Thus, the miRNA pathway is a new pathogenic mechanism of CagA
A new integrated and homogenized global monthly land surface air temperature dataset for the period since 1900
A new dataset of integrated and homogenized monthly surface air temperature over global land for the period since 1900 [China Meteorological Administration global Land Surface Air Temperature (CMA-LSAT)] is developed. In total, 14 sources have been collected and integrated into the newly developed dataset, including three global (CRUTEM4, GHCN, and BEST), three regional and eight national sources. Duplicate stations are identified, and those with the higher priority are chosen or spliced. Then, a consistency test and a climate outlier test are conducted to ensure that each station series is quality controlled. Next, two steps are adopted to assure the homogeneity of the station series: (1) homogenized station series in existing national datasets (by National Meteorological Services) are directly integrated into the dataset without any changes (50% of all stations), and (2) the inhomogeneities are detected and adjusted for in the remaining data series using a penalized maximal t test (50% of all stations). Based on the dataset, we re-assess the temperature changes in global and regional areas compared with GHCN-V3 and CRUTEM4, as well as the temperature changes during the three periods of 1900â2014, 1979â2014 and 1998â2014. The best estimates of warming trends and there 95% confidence ranges for 1900â2014 are approximately 0.102âÂąâ0.006â°C/decade for the whole year, and 0.104âÂąâ0.009, 0.112âÂąâ0.007, 0.090âÂąâ0.006, and 0.092âÂąâ0.007â°C/decade for the DJF (December, January, February), MAM, JJA, and SON seasons, respectively. MAM saw the most significant warming trend in both 1900â2014 and 1979â2014. For an even shorter and more recent period (1998â2014), MAM, JJA and SON show similar warming trends, while DJF shows opposite trends. The results show that the ability of CMA-LAST for describing the global temperature changes is similar with other existing products, while there are some differences when describing regional temperature changes
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at TeV
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb
collisions at = 2.76 TeV have been measured by the ALICE
Collaboration at the LHC. The data are presented for central and peripheral
collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross
section. The measured charged particle spectra in and GeV/ are compared to the expectation in pp collisions at the same
, scaled by the number of underlying nucleon-nucleon
collisions. The comparison is expressed in terms of the nuclear modification
factor . The result indicates only weak medium effects ( 0.7) in peripheral collisions. In central collisions,
reaches a minimum of about 0.14 at -7GeV/ and increases
significantly at larger . The measured suppression of high- particles is stronger than that observed at lower collision energies,
indicating that a very dense medium is formed in central Pb-Pb collisions at
the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98
The Zea mays mutants opaque-2 and opaque-7 disclose extensive changes in endosperm metabolism as revealed by protein, amino acid, and transcriptome-wide analyses
<p>Abstract</p> <p>Background</p> <p>The changes in storage reserve accumulation during maize (<it>Zea mays </it>L.) grain maturation are well established. However, the key molecular determinants controlling carbon flux to the grain and the partitioning of carbon to starch and protein are more elusive. The <it>Opaque-2 </it>(<it>O2</it>) gene, one of the best-characterized plant transcription factors, is a good example of the integration of carbohydrate, amino acid and storage protein metabolisms in maize endosperm development. Evidence also indicates that the <it>Opaque-7 </it>(<it>O7</it>) gene plays a role in affecting endosperm metabolism. The focus of this study was to assess the changes induced by the <it>o2 </it>and <it>o7 </it>mutations on maize endosperm metabolism by evaluating protein and amino acid composition and by transcriptome profiling, in order to investigate the functional interplay between these two genes in single and double mutants.</p> <p>Results</p> <p>We show that the overall amino acid composition of the mutants analyzed appeared similar. Each mutant had a high Lys and reduced Glx and Leu content with respect to wild type. Gene expression profiling, based on a unigene set composed of 7,250 ESTs, allowed us to identify a series of mutant-related down (17.1%) and up-regulated (3.2%) transcripts. Several differentially expressed ESTs homologous to genes encoding enzymes involved in amino acid synthesis, carbon metabolism (TCA cycle and glycolysis), in storage protein and starch metabolism, in gene transcription and translation processes, in signal transduction, and in protein, fatty acid, and lipid synthesis were identified. Our analyses demonstrate that the mutants investigated are pleiotropic and play a critical role in several endosperm-related metabolic processes. Pleiotropic effects were less evident in the <it>o7 </it>mutant, but severe in the <it>o2 </it>and <it>o2o7 </it>backgrounds, with large changes in gene expression patterns, affecting a broad range of kernel-expressed genes.</p> <p>Conclusion</p> <p>Although, by necessity, this paper is descriptive and more work is required to define gene functions and dissect the complex regulation of gene expression, the genes isolated and characterized to date give us an intriguing insight into the mechanisms underlying endosperm metabolism.</p
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
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