Leveraging plasmonic hot electrons to quench defect emission in metal-semiconductor nanostructured hybrids

Modeling light-matter interactions in hybrid plasmonic materials is vital to their widening relevance from optoelectronics to photocatalysis. Here, we explore photoluminescence (PL) from ZnO nanorods (ZNRs) embedded with gold nanoparticles (Au NPs). A progressive increase in Au NP concentration introduces significant structural disorder and defects in ZNRs, which paradoxically quenches defect related visible PL while intensifying the near band edge (NBE) emission. Under UV excitation, the simulated semi-classical model realizes PL from ZnO with sub-bandgap defect states, eliciting visible emissions that are absorbed by Au NPs to generate a non-equilibrium hot carrier distribution. The photo-stimulated hot carriers, transferred to ZnO, substantially modify its steady-state luminescence, reducing NBE emission lifetime and altering the abundance of ionized defect states, finally reducing visible emission. The simulations show that the change in the interfacial band bending at the Au-ZnO interface under optical illumination facilitates charge transfer between the components. This work provides a general foundation to observe and model the hot carrier dynamics and strong light-matter interactions in hybrid plasmonic systems.

Symmetric domain segmentation in WS2flakes: correlating spatially resolved photoluminescence, conductance with valley polarization

The incidence of intra-flake heterogeneity of spectroscopic and electrical properties in chemical vapour deposited (CVD) WS₂flakes is explored in a multi-physics investigation via spatially resolved spectroscopic maps correlated with electrical, electronic and mechanical properties. The investigation demonstrates that the three-fold symmetric segregation of spectroscopic response, in topographically uniform WS₂flakes are accompanied by commensurate segmentation of electronic properties e.g. local carrier density and the differences in the mechanics of tip-sample interactions, evidenced via scanning probe microscopy phase maps. Overall, the differences are understood to originate from point defects, namely sulfur vacancies within the flake along with a dominant role played by the substrate. While evolution of the multi-physics maps upon sulfur annealing elucidates the role played by sulfur vacancy, substrate-induced effects are investigated by contrasting data from WS₂flake on Si and Au surfaces. Local charge depletion induced by the nature of the sample-substrate junction in case of WS₂on Au is seen to invert the electrical response with comprehensible effects on their spectroscopic properties. Finally, the role of these optoelectronic properties in preserving valley polarization that affects valleytronic applications in WS₂flakes, is investigated via circular polarization discriminated photoluminescence experiments. The study provides a thorough understanding of spatial heterogeneity in optoelectronic properties of WS₂and other transition metal chalcogenides, which are critical for device fabrication and potential applications.

Imaging with Raman photons: a novel use of mixed-mode spectroscopy

Surface enhanced Raman spectroscopy is today an established technique used for chemical fingerprinting. Here, we showcase an engineered hierarchical substrate, in which the plasmonically active regions, restricted to a micron scale, two dimensional hexagonal pattern are examined. Spatial variation of the enhanced Raman signal from any analyte, uniformly coating the substrate, consequently bears a high registry with the underlying pattern. This spatially contrasted enhancement allows optical imaging of the 2D pattern solely using the Raman scattered photons from the analyte. While the pattern brightness and contrast determine analyte identification and detection sensitivity, hyperspectral imaging can be exploited for increasing specificity. Proof of concept demonstration of the technique is carried out via the acquisition of Raman images with rhodamine and fluorescein dyes and then applied to detect glucose in 40 mM concentration. The large area optical imaging and the requirement of long-range uniformity in the detected patterns for positive analyte detection, is implemented using a machine learning based pattern recognition protocol which also increases the statistical confidence of detection. This simultaneous, large area signal detection sacrifices continuous spectral information at the cost of speed, reproducibility and minimising human error via automation of detection in the hyperspectral imaging technique presented here.

DNA hypomethylation is the plausible driver of heat stress adaptation in Linum usitatissimum

Heat stress has a significant impact on the climatic adaptation of flax, a cool-season economic crop. Genome-wide DNA methylation patterns are crucial for understanding how flax cultivars respond to heat adversities. It is worth noting that the DNA methylome in flax has yet to be investigated at the nucleotide level. Although heat stress above 40°C caused oxidative damage in flax leaves, 5-azacytidine, a hypomethylating agent, reduced this effect by 15%-24%. Differences in the expression of the LuMET1 (DNA methyltransferase) gene suggested that DNA methylation/demethylation may play a major role in the flax heat stress response. Thus, whole-genome bisulfite sequencing-derived DNA methylation profiles in flax, with or without heat stress and 5-azaC, were developed and analyzed here. In response to heat stress, a high percentage of significant differentially methylated regions (DMRs), particularly hypomethylated DMRs, were identified in the CHH nucleotide sequence context (H = A/T/C). Some of these DMRs overlapped with transposable element insertions. The majority of DMRs were discovered in intergenic regions, but several DMR loci were also found near genes relevant to heat stress response and epigenetic processes. These DMRs, in particular, are linked to CpG islands, implying a possible role in promoter methylation and gene silencing. The DMRs discovered in this study are crucial for understanding and identifying the key players in heat stress response in flax, which will help in developing climate-smart flax varieties.

Controlling the macroscopic electrical properties of reduced graphene oxide by nanoscale writing of electronic channels

The allure of all-carbon electronics stems from the spread of its physical properties across all its allotropes. The scheme also harbours unique challenges, such as tunability of band gap, variability of doping and defect control. Here, we explore the technique of scanning probe tip-induced nanoscale reduction of graphene oxide (GO), which nucleates conducting, [Formula: see text] rich graphitic regions on the insulating GO background. The flexibility of direct writing is supplemented with control over the degree of reduction and tunability of band gap through macroscopic control parameters. The fabricated reduced GO channels and ensuing devices are investigated via spectroscopy and temperature and bias-dependent electrical transport and correlated with spatially resolved electronic properties, using surface potentiometry. The presence of carrier localization effects, induced by the phase-separated [Formula: see text] domains, and large local electric field fluctuations are reflected in the non-linear transport across the channels. Together, the results indicate a complex transport phenomenon, which may be variously dominated by tunnelling or variable range hopping or activated depending on the electronic state of the material.

Refractive index-assisted UV/Vis spectrophotometry to overcome spectral interference by impurities

A major challenge hindering the application of techniques like UV/Vis spectrophotometry in determining concentration is spectral interference from contaminants. Since molar absorptivities vary significantly, even minuscule amounts of specific contaminants may cause relatively large errors in UV/Vis spectrophotometry based quantification. Current methods to deal with this are slow, cost-intensive, or ineffective for unknown interferents. We propose constrained refractometry as an expedient technique to aid UV/Vis spectrophotometry, avoiding large errors due to spectral interference. Based on a modified Lorentz Lorenz equation, the technique helps not only in detecting and reducing error from unknown contaminants but also in identifying the significant impurity. Experimental results show a significant reduction of error in concentration determination even for multiple unknown interfering contaminants.

Thickness induced metal to insulator charge transport and unusual hydrogen response in granular palladium nanofilms

This work reports a systematic study of the evolution of charge transport properties in granular ultra-thin films of palladium of thicknesses varying between 6 nm and 2 nm. While the films with thickness >4 nm exhibit metallic behaviour, that at 3 nm thickness undergoes a metal-insulator transition at 19.5 K. In contrast, the 2 nm thick film remained insulating at all temperatures, with transport following Mott's variable range hopping. At room temperature, while the thicker films exhibit resistance decrease upon H2 exposure, the insulating film showed an anomalous initial resistance increase before switching to a subsequent decrease. The nanostructure dependent transport and the ensuing H2 response is modeled on a percolation model, which also explores the relevance of film thickness as a macroscopic control parameter to engineer the desired system response in granular metal films.

Interaction of ZnO nanorods with plasmonic metal nanoparticles and semiconductor quantum dots

We model the enhancement of near band edge emission from ZnO nanorods using plasmonic metal nanoparticles and compare it with emission enhancement from ZnO with semiconducting quantum dots. Selected CdSe quantum dots with absorption energies close to those of Ag and Au nanoparticles are chosen to construct model systems with ZnO to comprehend the role of ZnO's intrinsic defects and plasmonic excitation in realizing the spectrally selective luminescence enhancement. Excitation wavelength dependent photoluminescence spectra along with theoretical models quantifying the related transitions and plasmonic absorption reveal that a complex mechanism of charge transfer between the ZnO nanorods and metal nanoparticles or quantum dots is essential along with an optimal energy band alignment for realizing emission enhancement. The theoretical model presented also provides a direct method of quantifying the relative transition rate constants associated with various electronic transitions in ZnO and their change upon the incorporation of plasmonic nanoparticles. The results indicate that, while the presence of deep level defect states may facilitate the essential charge transfer process between ZnO and the plasmonic nanoparticles, their presence alone does not guarantee UV emission enhancement and strong plasmonic coupling between the two systems. The results offer clues to designing novel multicomponent systems with coupled plasmonic and charge transfer effects for applications in charge localization, energy harvesting, and luminescence enhancement, especially in electrically triggered nanophotonic applications.

Electrocatalysis on Edge-Rich Spiral WS2 for Hydrogen Evolution

Transition metal dichalcogenides (TMDs) exhibit promising catalytic properties for hydrogen generation, and several approaches including defect engineering have been shown to increase the active catalytic sites. Despite preliminary understandings in defect engineering, insights on the role of various types of defects in TMDs for hydrogen evolution catalysis are limited. Screw dislocation-driven (SDD) growth is a line defect and yields fascinating spiral and pyramidal morphologies for TMDs with a large number of edge sites, resulting in very interesting electronic and catalytic properties. The role of dislocation lines and edge sites of these spiral structures on their hydrogen evolution catalytic properties is unexplored. Here we show that the large number of active edge sites connected together by dislocation lines in the vertical direction for a spiral WS₂ domain results in exceptional catalytic properties toward hydrogen evolution reaction. A micro-electrochemical cell fabricated by photo- and electron beam-lithography processes is used to study the electrocatalytic activity of a single spiral WS₂ domain, controllably grown by chemical vapor deposition. Conductive atomic force microscopy studies show improved vertical conduction for the spiral domain, which is compared with monolayer and mechanically exfoliated thick WS₂ flakes. The obtained results are interesting and shed light on the role of SDD line defects, which contribute to large number of edge sites without compromising the vertical electrical conduction, on the electrocatalytic properties of TMDs for hydrogen evolution.

Negative photoresponse in ZnO-PEDOT:PSS nanocomposites and photogating effects

We report negative photoresponse or increase of resistance in nanocomposites of n-type ZnO nanoparticles dispersed in a p-type polymer (PEDOT:PSS) under UV and visible light excitation, contrary to that of planar heterojunctions of the constituents. The underlying mechanism of charge transport, specifically negative photoresponse, is explored using spectroscopic and opto-electrical characterisation. Systemic variability in conductance, photoresponse sensitivity and rate with fractional nanoparticle loading in the nanocomposite is demonstrated. Here, photogenerated electrons in ZnO nanoparticles, trapped by the unbiased interfacial barrier, are understood to localize holes in the PEDOT:PSS conduction channel thereby increasing the overall nanocomposite resistance. Reversibility of the negative PR although with a slow decay rate bears testament to the proposed photogating mechanism as opposed to photocatalytic activity. Replacement of the p-type polymer with an electron transport matrix turns the negative photoresponse positive accentuating the role of the interfacial barrier in tuning the optoelectronic response of the composites. These hybrid materials and their unusual behaviour provide alternative strategies for building devices with novel photogating effects, exploiting the properties of their nanostructured forms.

Genomic insights into HSFs as candidate genes for high-temperature stress adaptation and gene editing with minimal off-target effects in flax

Flax (Linum usitatissimum) is a cool season crop commercially cultivated for seed oil and stem fibre production. A comprehensive characterization of the heat shock factor (HSF) candidate genes in flax can accelerate genetic improvement and adaptive breeding for high temperature stress tolerance. We report the genome-wide identification of 34 putative HSF genes from the flax genome, which we mapped on 14 of the 15 chromosomes. Through comparative homology analysis, we classified these genes into three broad groups, and sub-groups. The arrangement of HSF-specific protein motifs, DNA-binding domain (DBD) and hydrophobic heptad repeat (HR-A/B), and exon-intron boundaries substantiated the phylogenetic separation of these genes. Orthologous relationships and evolutionary analysis revealed that the co-evolution of the LusHSF genes was due to recent genome duplication events. Digital and RT-qPCR analyses provided significant evidence of the differential expression of the LusHSF genes in various tissues, at various developmental stages, and in response to high-temperature stress. The co-localization of diverse cis-acting elements in the promoters of the LusHSF genes further emphasized their regulatory roles in the abiotic stress response. We further confirmed DNA-binding sites on the LusHSF proteins and designed guide RNA sequences for gene editing with minimal off-target effects. These results will hasten functional investigations of LusHSFs or assist in devising genome engineering strategies to develop high-temperature stress tolerant flax cultivars.

Azimuthal Anisotropy of Heavy-Flavor Decay Electrons in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|<0.8) are measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v_{2}) for heavy-flavor decay electrons in the transverse momentum interval 1.5<p_{T}<4  GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v_{2} measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.

Transcriptome profiling uncovers β-galactosidases of diverse domain classes influencing hypocotyl development in jute (Corchorus capsularis L.)

Enzyme β-galactosidase (EC 3.2.1.23) is known to influence vascular differentiation during early vegetative growth of plants, but its role in hypocotyl development is not yet fully understood. We generated the hypocotyl transcriptome data of a hypocotyl-defect jute (Corchorus capsularis L.) mutant (52,393 unigenes) and its wild-type (WT) cv. JRC-212 (44,720 unigenes) by paired-end RNA-seq and identified 11 isoforms of β-galactosidase, using a combination of sequence annotation, domain identification and structural-homology modeling. Phylogenetic analysis classified the jute β-galactosidases into six subfamilies of glycoside hydrolase-35 family, which are closely related to homologs from Malvaceous species. We also report here the expression of a β-galactosidase of glycoside hydrolase-2 family that was earlier considered to be absent in higher plants. Comparative analysis of domain structure allowed us to propose a domain-centric evolution of the five classes of plant β-galactosidases. Further, we observed 1.8-12.2-fold higher expression of nine β-galactosidase isoforms in the mutant hypocotyl, which was characterized by slower growth, undulated shape and deformed cell wall. In vitro and in vivo β-galactosidase activities were also higher in the mutant hypocotyl. Phenotypic analysis supported a significant (P ≤ 0.01) positive correlation between enzyme activity and undulated hypocotyl. Taken together, our study identifies the complete set of β-galactosidases expressed in the jute hypocotyl, and provides compelling evidence that they may be involved in cell wall degradation during hypocotyl development.

Genome-wide regulatory gene-derived SSRs reveal genetic differentiation and population structure in fiber flax genotypes

We designed a set of 580 simple sequence repeat markers; 506 from transcription factor-coding genes, and 74 from long non-coding RNAs and designated them as regulatory gene-derived simple sequence repeat (ReG-SSR) markers. From this set, we could anchor 559 ReG-SSR markers on 15 flax chromosomes with an average marker distance of 0.56 Mb. Thirty-one polymorphic ReG-SSR primers, amplifying SSR loci length of at least 20 bp were chosen from 134 screened primers. This primer set was used to characterize a diversity panel of 93 flax accessions. The panel included 33 accessions from India, including released varieties, dual-purpose lines and landraces, and 60 fiber flax accessions from the global core collection. Thirty-one ReG-SSR markers generated 76 alleles, with an average of 2.5 alleles per primer and a mean allele frequency of 0.77. These markers recorded 0.32 average gene diversity, 0.26 polymorphism information content and 1.35% null alleles. All the 31 ReG-SSR loci were found selectively neutral and showed no evidence of population reduction. A model-based clustering analysis separated the flax accessions into two sub-populations-Indian and global, with some accessions showing admixtures. The distinct clustering pattern of the Indian accessions compared to the global accessions, conforms to the principal coordinate analysis, genetic dissimilarity-based unweighted neighbor-joining tree and analysis of molecular variance. Fourteen flax accessions with 99.3% allelic richness were found optimum to adopt in breeding programs. In summary, the genome-wide ReG-SSR markers will serve as a functional marker resource for genetic and phenotypic relationship studies, marker-assisted selections, and provide a basis for selection of accessions from the Indian and global gene pool in fiber flax breeding programs.

D-Meson Azimuthal Anisotropy in Midcentral Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV

The azimuthal anisotropy coefficient v_{2} of prompt D^{0}, D^{+}, D^{*+}, and D_{s}^{+} mesons was measured in midcentral (30%-50% centrality class) Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02  TeV, with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays at midrapidity, |y|<0.8, in the transverse momentum interval 1<p_{T}<24  GeV/c. The measured D-meson v_{2} has similar values as that of charged pions. The D_{s}^{+} v_{2}, measured for the first time, is found to be compatible with that of nonstrange D mesons. The measurements are compared with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium and have the potential to constrain medium parameters.

Resistive switching in individual ZnO nanorods: delineating the ionic current by photo-stimulation

Resistive switching in nanostructured metal oxide semiconductors has been broadly understood to originate from the dynamics of its native point defects. Experimental results of switching observed in individual n-ZnO nanorods grown on a p-type polymer is presented along with an empirical model describing the underlying defect dynamics necessary to observe bi-polar switching. Selective photo excitation of electrons into the defect states delineates the incidence and role of an ionic current in the switching behavior. The understanding further extends to the observance of a negative differential resistance regime that is often coincident in such systems. The analysis not only unifies the underlying physics of the two phenomena but also offers further confidence in the proposed mechanism. We conclude by demonstrating that the effective memresistance of such devices is a strong function of the operating bias and identify parameters that optimize switching performance.

J/ψ Elliptic Flow in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

We report a precise measurement of the J/ψ elliptic flow in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The J/ψ mesons are reconstructed at midrapidity (|y|<0.9) in the dielectron decay channel and at forward rapidity (2.5<y<4.0) in the dimuon channel, both down to zero transverse momentum. At forward rapidity, the elliptic flow v_{2} of the J/ψ is studied as a function of the transverse momentum and centrality. A positive v_{2} is observed in the transverse momentum range 2<p_{T}<8  GeV/c in the three centrality classes studied and confirms with higher statistics our earlier results at sqrt[s_{NN}]=2.76  TeV in semicentral collisions. At midrapidity, the J/ψ  v_{2} is investigated as a function of the transverse momentum in semicentral collisions and found to be in agreement with the measurements at forward rapidity. These results are compared to transport model calculations. The comparison supports the idea that at low p_{T} the elliptic flow of the J/ψ originates from the thermalization of charm quarks in the deconfined medium but suggests that additional mechanisms might be missing in the models.

Novel routes to electromagnetic enhancement and its characterisation in surface- and tip-enhanced Raman scattering

Quantitative understanding of the electromagnetic component in enhanced Raman spectroscopy is often difficult to achieve on account of the complex substrate structures utilised. We therefore turn to two structurally simple systems amenable to detailed modelling. The first is tip-enhanced Raman scattering under electron scanning tunnelling microscopy control (STM-TERS) where, appealing to understanding developed in the context of photon emission from STM, it is argued that the localised surface plasmon modes driving the Raman enhancement exist in the visible and near-infrared regime only by virtue of significant modification to the optical properties of the tip and sample metals (gold here). This is due to the strong dc field-induced (∼10⁹ V m^-1) non-linear corrections to the dielectric function of gold via the third order susceptibility term in the polarisation. Also, sub-5 nm spatial resolution is shown in the modelling. Secondly, we suggest a novel deployment of hybrid plasmonic waveguide modes in surface enhanced Raman scattering (HPWG-SERS). This delivers strong confinement of electromagnetic energy in a ∼10 nm oxide 'gap' between a high-index dielectric material of nanoscale width (a GaAs nanorod and a 100 nm Si slab are considered here) and a metal, yielding a monotonic variation in the Raman enhancement factor as a function of wavelength with no long-wavelength cut-off, both features that contrast with STM-TERS.

Radiotherapy dose-distribution to the perirectal fat space (PRS) is related to gastrointestinal control-related complications

Traditionally rectal symptoms following pelvic/prostate radiotherapy are correlated to the dosimetry of the anorectum or a substructure of this. It has been suggested that the perirectal fat space (PRS) surrounding the rectum may also be relevant. This study considers the delineation and dosimetry of the PRS related to both rectal bleeding and control-related toxicity. Initially, a case-control cohort of 100 patients from the RADAR study were chosen based on presence/absence of rectal control-related toxicity. Automated contouring was developed to delineate the PRS. 79 of the 100 auto-segmentations were considered successful. Balanced case-control cohorts were defined from these cases. Atlas of Complication Incidence (ACI) were generated to relate the DVH of the PRS with specific rectal symptoms; rectal bleeding and control-related symptoms (LENT/SOM). ACI demonstrated that control-related symptoms were related to the dose distribution to the PRS which was confirmed with Wilcoxon rank sum test (p < 0.05). To the authors knowledge this is the first study implicating the dose distribution to the PRS to the incidence of control-related symptoms of rectal toxicity.

Anomalous Evolution of the Near-Side Jet Peak Shape in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a p_{T} region inaccessible by direct jet identification. In these measurements pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the shape of the near-side peak formed by particles associated with a higher p_{T} trigger particle (1<p_{T,trig}<8  GeV/c). A combined fit of the near-side peak and long-range correlations is applied to the data allowing the extraction of the centrality evolution of the peak shape in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV. A significant broadening of the peak in the Δη direction at low p_{T} is found from peripheral to central collisions, which vanishes above 4  GeV/c, while in the Δφ direction the peak is almost independent of centrality. For the 10% most central collisions and 1<p_{T,assoc}<2  GeV/c, 1<p_{T,trig}<3  GeV/c a novel feature is observed: a depletion develops around the center of the peak. The results are compared to pp collisions at the same center of mass energy and ampt model simulations. The comparison to the investigated models suggests that the broadening and the development of the depletion is connected to the strength of radial and longitudinal flow.

Scanning tunnelling microscope light emission: Finite temperature current noise and over cut-off emission

The spectral distribution of light emitted from a scanning tunnelling microscope junction not only bears its intrinsic plasmonic signature but is also imprinted with the characteristics of optical frequency fluc- tuations of the tunnel current. Experimental spectra from gold-gold tunnel junctions are presented that show a strong bias (V _b ) dependence, curiously with emission at energies higher than the quantum cut-off (eV _b ); a component that decays monotonically with increasing bias. The spectral evolution is explained by developing a theoretical model for the power spectral density of tunnel current fluctuations, incorporating finite temperature contribution through consideration of the quantum transport in the system. Notably, the observed decay of the over cut-off emission is found to be critically associated with, and well explained in terms of the variation in junction conductance with V _b . The investigation highlights the scope of plasmon-mediated light emission as a unique probe of high frequency fluctuations in electronic systems that are fundamental to the electrical generation and control of plasmons.

Energy dependence of forward-rapidity [Formula: see text] and [Formula: see text] production in pp collisions at the LHC

We present results on transverse momentum ([Formula: see text]) and rapidity ([Formula: see text]) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive [Formula: see text] and [Formula: see text] at forward rapidity ([Formula: see text]) as well as [Formula: see text]-to-[Formula: see text] cross section ratios. These quantities are measured in pp collisions at center of mass energies [Formula: see text] and 13 TeV with the ALICE detector. Both charmonium states are reconstructed in the dimuon decay channel, using the muon spectrometer. A comprehensive comparison to inclusive charmonium cross sections measured at [Formula: see text], 7 and 8 TeV is performed. A comparison to non-relativistic quantum chromodynamics and fixed-order next-to-leading logarithm calculations, which describe prompt and non-prompt charmonium production respectively, is also presented. A good description of the data is obtained over the full [Formula: see text] range, provided that both contributions are summed. In particular, it is found that for [Formula: see text] GeV/c the non-prompt contribution reaches up to 50% of the total charmonium yield.

Production of Σ(1385)± and Ξ(1530)0 in p-Pb collisions at sNN=5.02 TeV

The transverse momentum distributions of the strange and double-strange hyperon resonances (Σ ( 1385 ) ± , Ξ ( 1530 ) 0 ) produced in p-Pb collisions at s NN = 5.02 TeV were measured in the rapidity range - 0.5 < y CMS < 0 for event classes corresponding to different charged-particle multiplicity densities, ⟨ dN ch /dη lab ⟩ . The mean transverse momentum values are presented as a function of ⟨ dN ch /dη lab ⟩ , as well as a function of the particle masses and compared with previous results on hyperon production. The integrated yield ratios of excited to ground-state hyperons are constant as a function of ⟨ dN ch /dη lab ⟩ . The equivalent ratios to pions exhibit an increase with ⟨ dN ch /dη lab ⟩ , depending on their strangeness content.

Production of [Formula: see text] and [Formula: see text] mesons up to high transverse momentum in pp collisions at 2.76 TeV

The invariant differential cross sections for inclusive [Formula: see text] and [Formula: see text] mesons at midrapidity were measured in pp collisions at [Formula: see text] TeV for transverse momenta [Formula: see text] GeV/c and [Formula: see text] GeV/c, respectively, using the ALICE detector. This large range in [Formula: see text] was achieved by combining various analysis techniques and different triggers involving the electromagnetic calorimeter (EMCal). In particular, a new single-cluster, shower-shape based method was developed for the identification of high-[Formula: see text] neutral pions, which exploits that the showers originating from their decay photons overlap in the EMCal. Above 4 GeV/[Formula: see text], the measured cross sections are found to exhibit a similar power-law behavior with an exponent of about 6.3. Next-to-leading-order perturbative QCD calculations differ from the measured cross sections by about 30% for the [Formula: see text], and between 30-50% for the [Formula: see text] meson, while generator-level simulations with PYTHIA 8.2 describe the data to better than 10-30%, except at [Formula: see text] GeV/[Formula: see text]. The new data can therefore be used to further improve the theoretical description of [Formula: see text] and [Formula: see text] meson production.

Flow Dominance and Factorization of Transverse Momentum Correlations in Pb-Pb Collisions at the LHC

We present the first measurement of the two-particle transverse momentum differential correlation function, P_{2}≡⟨Δp_{T}Δp_{T}⟩/⟨p_{T}⟩^{2}, in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV. Results for P_{2} are reported as a function of the relative pseudorapidity (Δη) and azimuthal angle (Δφ) between two particles for different collision centralities. The Δϕ dependence is found to be largely independent of Δη for |Δη|≥0.9. In the 5% most central Pb-Pb collisions, the two-particle transverse momentum correlation function exhibits a clear double-hump structure around Δφ=π (i.e., on the away side), which is not observed in number correlations in the same centrality range, and thus provides an indication of the dominance of triangular flow in this collision centrality. Fourier decompositions of P_{2}, studied as a function of the collision centrality, show that correlations at |Δη|≥0.9 can be well reproduced by a flow ansatz based on the notion that measured transverse momentum correlations are strictly determined by the collective motion of the system.

Measurement of azimuthal correlations of D mesons with charged particles in pp collisions at [Formula: see text] TeV and p-Pb collisions at [Formula: see text] TeV

The azimuthal correlations of D mesons with charged particles were measured with the ALICE apparatus in pp collisions at [Formula: see text] and p-Pb collisions at [Formula: see text] at the Large Hadron Collider. [Formula: see text], [Formula: see text], and [Formula: see text] mesons and their charge conjugates with transverse momentum [Formula: see text] and rapidity in the nucleon-nucleon centre-of-mass system [Formula: see text] (pp collisions) and [Formula: see text] (p-Pb collisions) were correlated to charged particles with [Formula: see text]. The yield of charged particles in the correlation peak induced by the jet containing the D meson and the peak width are compatible within uncertainties in the two collision systems. The data are described within uncertainties by Monte-Carlo simulations based on PYTHIA, POWHEG, and EPOS 3 event generators.

SSR and morphological trait based population structure analysis of 130 diverse flax (Linum usitatissimum L.) accessions

A total of 130 flax accessions of diverse morphotypes and worldwide origin were assessed for genetic diversity and population structure using 11 morphological traits and microsatellite markers (15 gSSRs and 7 EST-SSRs). Analysis performed after classifying these accessions on the basis of plant height, branching pattern, seed size, Indian/foreign origin into six categories called sub-populations viz. fibre type exotic, fibre type indigenous, intermediate type exotic, intermediate type indigenous, linseed type exotic and linseed type indigenous. The study assessed different diversity indices, AMOVA, population structure and included a principal coordinate analysis based on different marker systems. The highest diversity was exhibited by gSSR markers (SI=0.46; He=0.31; P=85.11). AMOVA based on all markers explained significant difference among fibre type, intermediate type and linseed type populations of flax. In terms of variation explained by different markers, EST-SSR markers (12%) better differentiated flax populations compared to morphological (9%) and gSSR (6%) markers at P=0.01. The maximum Nei's unbiased genetic distance (D=0.11) was observed between fibre type and linseed type exotic sub-populations based on EST-SSR markers. The combined structure analysis by using all markers grouped Indian fibre type accessions (63.4%) in a separate cluster along with the Indian intermediate type (48.7%), whereas Indian accessions (82.16%) of linseed type constituted an independent cluster. These findings were supported by the results of the principal coordinate analysis. Morphological markers employed in the study found complementary with microsatellite based markers in deciphering genetic diversity and population structure of the flax germplasm.

Network over-connectivity differentiates autism spectrum disorder from other developmental disorders in toddlers: A diffusion MRI study

Advanced connectivity studies in toddlers with Autism Spectrum Disorder (ASD) are increasing and consistently reporting a disruption of brain connectivity. However, most of these studies compare ASD and typically developing subjects, thus providing little information on the specificity of the abnormalities detected in comparison with other developmental disorders (other-DD). We recruited subjects aged below 36 months who received a clinical diagnosis of Neurodevelopmental Disorder (32 ASD and 16 other-DD including intellectual disability and language disorder) according to DSM-IV TR. Structural and diffusion MRI were acquired to perform whole brain probabilistic and anatomically constrained tractography. Network connectivity matrices were built encoding the number of streamlines (D_NUM ) and the tract-averaged fractional anisotropy (D_FA ) values connecting each pair of cortical and subcortical regions. Network Based Statistics (NBS) was finally applied on the connectivity matrices to evaluate the network differences between the ASD and other-DD groups. The network differences resulted in an over-connectivity pattern (i.e., higher D_NUM and D_FA values) in the ASD group with a significance of P < 0.05. No contra-comparison results were found. The over-connectivity pattern in ASD occurred in networks primarily involving the fronto-temporal nodes, known to be crucial for social-skill development and basal ganglia, related to restricted and repetitive behaviours in ASD. To our knowledge, this is the first network-based diffusion study comparing toddlers with ASD and those with other-DD. Results indicate the detection of different connectivity patterns in ASD and other-DD at an age when clinical differential diagnosis is often challenging. Hum Brain Mapp 38:2333-2344, 2017. © 2017 Wiley Periodicals, Inc.

Correlated Event-by-Event Fluctuations of Flow Harmonics in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

We report the measurements of correlations between event-by-event fluctuations of amplitudes of anisotropic flow harmonics in nucleus-nucleus collisions, obtained for the first time using a new analysis method based on multiparticle cumulants in mixed harmonics. This novel method is robust against systematic biases originating from nonflow effects and by construction any dependence on symmetry planes is eliminated. We demonstrate that correlations of flow harmonics exhibit a better sensitivity to medium properties than the individual flow harmonics. The new measurements are performed in Pb-Pb collisions at the center-of-mass energy per nucleon pair of sqrt[s_{NN}]=2.76  TeV by the ALICE experiment at the Large Hadron Collider. The centrality dependence of correlation between event-by-event fluctuations of the elliptic v_{2} and quadrangular v_{4} flow harmonics, as well as of anticorrelation between v_{2} and triangular v_{3} flow harmonics are presented. The results cover two different regimes of the initial state configurations: geometry dominated (in midcentral collisions) and fluctuation dominated (in the most central collisions). Comparisons are made to predictions from Monte Carlo Glauber, viscous hydrodynamics, ampt, and hijing models. Together with the existing measurements of the individual flow harmonics the presented results provide further constraints on the initial conditions and the transport properties of the system produced in heavy-ion collisions.

Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The pseudorapidity density of charged particles, dN_{ch}/dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. For the 5% most central collisions, we measure a value of 1943±54. The rise in dN_{ch}/dη as a function of sqrt[s_{NN}] is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dN_{ch}/dη as a function of the average number of participant nucleons, ⟨N_{part}⟩, calculated in a Glauber model, is compared with the previous measurement at sqrt[s_{NN}]=2.76  TeV. A constant factor of about 1.2 describes the increase in dN_{ch}/dη from sqrt[s_{NN}]=2.76 to 5.02 TeV for all centrality classes, within the measured range of 0%-80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.

Measurement of an Excess in the Yield of J/ψ at Very Low p_{T} in Pb-Pb Collisions at sqrt[s]_{NN}=2.76 TeV

We report on the first measurement of an excess in the yield of J/ψ at very low transverse momentum (p_{T}<0.3  GeV/c) in peripheral hadronic Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV, performed by ALICE at the CERN LHC. Remarkably, the measured nuclear modification factor of J/ψ in the rapidity range 2.5<y<4 reaches about 7 (2) in the p_{T} range 0-0.3  GeV/c in the 70%-90% (50%-70%) centrality class. The J/ψ production cross section associated with the observed excess is obtained under the hypothesis that coherent photoproduction of J/ψ is the underlying physics mechanism. If confirmed, the observation of J/ψ coherent photoproduction in Pb-Pb collisions at impact parameters smaller than twice the nuclear radius opens new theoretical and experimental challenges and opportunities. In particular, coherent photoproduction accompanying hadronic collisions may provide insight into the dynamics of photoproduction and nuclear reactions, as well as become a novel probe of the quark-gluon plasma.

EB1 regulates attachment of Ska1 with microtubules by forming extended structures on the microtubule lattice

Kinetochore couples chromosome movement to dynamic microtubules, a process that is fundamental to mitosis in all eukaryotes but poorly understood. In vertebrates, spindle-kinetochore-associated (Ska1–3) protein complex plays an important role in this process. However, the proteins that stabilize Ska-mediated kinetochore-microtubule attachment remain unknown. Here we show that microtubule plus-end tracking protein EB1 facilitates Ska localization on microtubules in vertebrate cells. EB1 depletion results in a significant reduction of Ska1 recruitment onto microtubules and defects in mitotic chromosome alignment, which is also reflected in computational modelling. Biochemical experiments reveal that EB1 interacts with Ska1, facilitates Ska1-microtubule attachment and together stabilizes microtubules. Structural studies reveal that EB1 either with Ska1 or Ska complex forms extended structures on microtubule lattice. Results indicate that EB1 promotes Ska association with K-fibres and facilitates kinetochore-microtubule attachment. They also implicate that in vertebrates, chromosome coupling to dynamic microtubules could be mediated through EB1-Ska extended structures.

Ska1 is a kinetochore-localised protein that couples kinetochore movement to microtubule (MT) depolymerisation. Here Thomas et al. show that the MT +TIP binding protein EB1 recruits Ska1 to the MT-kinetochore interface and stabilises the interaction between Ska1 and MTs.

Centrality dependence of charged jet production in p-Pb collisions at [Formula: see text] = 5.02 TeV

Measurements of charged jet production as a function of centrality are presented for  p-Pb  collisions recorded at [Formula: see text] TeV with the ALICE detector. Centrality classes are determined via the energy deposit in neutron calorimeters at zero degree, close to the beam direction, to minimise dynamical biases of the selection. The corresponding number of participants or binary nucleon-nucleon collisions is determined based on the particle production in the Pb-going rapidity region. Jets have been reconstructed in the central rapidity region from charged particles with the anti-[Formula: see text] algorithm for resolution parameters [Formula: see text] and [Formula: see text] in the transverse momentum range 20 to 120 GeV/c. The reconstructed jet momentum and yields have been corrected for detector effects and underlying-event background. In the five centrality bins considered, the charged jet production in  p-Pb   collisions is consistent with the production expected from binary scaling from pp collisions. The ratio of jet yields reconstructed with the two different resolution parameters is also independent of the centrality selection, demonstrating the absence of major modifications of the radial jet structure in the reported centrality classes.

Production of K[Formula: see text](892)[Formula: see text] and [Formula: see text](1020) in p-Pb collisions at [Formula: see text] = 5.02 TeV

The production of K[Formula: see text](892)[Formula: see text] and [Formula: see text](1020) mesons has been measured in p-Pb collisions at [Formula: see text][Formula: see text] 5.02 TeV. K[Formula: see text] and [Formula: see text] are reconstructed via their decay into charged hadrons with the ALICE detector in the rapidity range [Formula: see text]. The transverse momentum spectra, measured as a function of the multiplicity, have a p[Formula: see text] range from 0 to 15 GeV/c for K[Formula: see text] and from 0.3 to 21 GeV/c for [Formula: see text]. Integrated yields, mean transverse momenta and particle ratios are reported and compared with results in pp collisions at [Formula: see text][Formula: see text] 7 TeV and Pb-Pb collisions at [Formula: see text][Formula: see text] 2.76 TeV. In Pb-Pb and p-Pb collisions, K[Formula: see text] and [Formula: see text] probe the hadronic phase of the system and contribute to the study of particle formation mechanisms by comparison with other identified hadrons. For this purpose, the mean transverse momenta and the differential proton-to-[Formula: see text] ratio are discussed as a function of the multiplicity of the event. The short-lived K[Formula: see text] is measured to investigate re-scattering effects, believed to be related to the size of the system and to the lifetime of the hadronic phase.

Inclusive quarkonium production at forward rapidity in pp collisions at [Formula: see text]TeV

We report on the inclusive production cross sections of [Formula: see text], [Formula: see text], [Formula: see text](1S), [Formula: see text](2S) and [Formula: see text](3S), measured at forward rapidity with the ALICE detector in [Formula: see text] collisions at a center-of-mass energy [Formula: see text] TeV. The analysis is based on data collected at the LHC and corresponds to an integrated luminosity of 1.23 pb[Formula: see text]. Quarkonia are reconstructed in the dimuon-decay channel. The differential production cross sections are measured as a function of the transverse momentum [Formula: see text] and rapidity y, over the [Formula: see text] ranges [Formula: see text] GeV/c for [Formula: see text], [Formula: see text] GeV/c for all other resonances, and for [Formula: see text]. The cross sections, integrated over [Formula: see text] and y, and assuming unpolarized quarkonia, are [Formula: see text] [Formula: see text]b, [Formula: see text] [Formula: see text]b, [Formula: see text] nb, [Formula: see text] nb and [Formula: see text] nb, where the first uncertainty is statistical and the second one is systematic. These values agree, within at most [Formula: see text], with measurements performed by the LHCb collaboration in the same rapidity range.

Anisotropic Flow of Charged Particles in Pb-Pb Collisions at √[s{NN}]=5.02 TeV

We report the first results of elliptic (v_{2}), triangular (v_{3}), and quadrangular (v_{4}) flow of charged particles in Pb-Pb collisions at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region |η|<0.8 and for the transverse momentum range 0.2<p_{T}<5  GeV/c. The anisotropic flow is measured using two-particle correlations with a pseudorapidity gap greater than one unit and with the multiparticle cumulant method. Compared to results from Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV, the anisotropic flow coefficients v_{2}, v_{3}, and v_{4} are found to increase by (3.0±0.6)%, (4.3±1.4)%, and (10.2±3.8)%, respectively, in the centrality range 0%-50%. This increase can be attributed mostly to an increase of the average transverse momentum between the two energies. The measurements are found to be compatible with hydrodynamic model calculations. This comparison provides a unique opportunity to test the validity of the hydrodynamic picture and the power to further discriminate between various possibilities for the temperature dependence of shear viscosity to entropy density ratio of the produced matter in heavy-ion collisions at the highest energies.

Multiplicity and transverse momentum evolution of charge-dependent correlations in pp, p-Pb, and Pb-Pb collisions at the LHC

We report on two-particle charge-dependent correlations in pp, p-Pb, and Pb-Pb collisions as a function of the pseudorapidity and azimuthal angle difference, [Formula: see text] and [Formula: see text] respectively. These correlations are studied using the balance function that probes the charge creation time and the development of collectivity in the produced system. The dependence of the balance function on the event multiplicity as well as on the trigger and associated particle transverse momentum ([Formula: see text]) in pp, p-Pb, and Pb-Pb collisions at [Formula: see text] 7, 5.02, and 2.76 TeV, respectively, are presented. In the low transverse momentum region, for [Formula: see text] GeV/c, the balance function becomes narrower in both [Formula: see text] and [Formula: see text] directions in all three systems for events with higher multiplicity. The experimental findings favor models that either incorporate some collective behavior (e.g. AMPT) or different mechanisms that lead to effects that resemble collective behavior (e.g. PYTHIA8 with color reconnection). For higher values of transverse momenta the balance function becomes even narrower but exhibits no multiplicity dependence, indicating that the observed narrowing with increasing multiplicity at low [Formula: see text] is a feature of bulk particle production.

Measurement of pion, kaon and proton production in proton-proton collisions at [Formula: see text] TeV

The measurement of primary [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production at mid-rapidity ([Formula: see text] 0.5) in proton-proton collisions at [Formula: see text][Formula: see text] 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/[Formula: see text] for pions, from 0.2 up to 6 GeV/[Formula: see text] for kaons and from 0.3 up to 6 GeV/[Formula: see text] for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.

Production of [Formula: see text] and [Formula: see text] in proton-proton collisions at [Formula: see text] 7 TeV

The production of the strange and double-strange baryon resonances ([Formula: see text], [Formula: see text]) has been measured at mid-rapidity ([Formula: see text][Formula: see text]) in proton-proton collisions at [Formula: see text] [Formula: see text] 7 TeV with the ALICE detector at the LHC. Transverse momentum spectra for inelastic collisions are compared to QCD-inspired models, which in general underpredict the data. A search for the [Formula: see text] pentaquark, decaying in the [Formula: see text] channel, has been carried out but no evidence is seen.

Zn interstitials and O vacancies responsible for n-type ZnO: what do the emission spectra reveal?

Evidencing interstitial Zn related defect states inside the conduction band of Zn-rich ZnO nanorods.

Exclusive J/ψ photoproduction off protons in ultraperipheral p-Pb collisions at √(s(NN))=5.02 TeV

We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sqrt[s_{NN}]=5.02  TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5<y<4 (p-Pb) or -3.6<y<-2.6 (Pb-p), and no other particles observed in the ALICE acceptance. The measured cross sections σ(γ+p→J/ψ+p) are 33.2±2.2(stat)±3.2(syst)±0.7(theor)  nb in p-Pb and 284±36(stat)_{-32}^{+27}(syst)±26(theor)  nb in Pb-p collisions. We measure this process up to about 700 GeV in the γp center of mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the J/ψ photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2×10^{-2} and ∼2×10^{-5}, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.

Measurement of prompt D-meson production in p-Pb collisions at √(s(NN))=5.02 TeV

The p_{T}-differential production cross sections of the prompt charmed mesons D^{0}, D^{+}, D^{*+}, and D_{s}^{+} and their charge conjugate in the rapidity interval -0.96<y_{cms}<0.04 were measured in p-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The nuclear modification factor R_{pPb}, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%-20% uncertainties with unity in the transverse momentum interval 1<p_{T}<24  GeV/c. No significant difference among the R_{pPb} of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.

First Report of a 16Sr I-B Phytoplasma Associated with Phyllody and Stem Fasciation of Flax (Linum usitatissimum) in India

Flax or linseed is grown as a fiber or oilseed crop in tropical and temperate regions. It is commercially cultivated in many countries of the world including Canada, China, India, the United States, Ethiopia, Pakistan, Russia, Poland, and Argentina (1). In December 2013, symptoms suggestive of phytoplasma infection were noticed on flax in different experimental fields of Central Research Institute for Jute and Allied Fibres (CRIJAF) research farm, Barrackpore, India, and the incidence was less than 2%. Because incidence of phytoplasma diseases are increasing worldwide, occurrence of a phytoplasma in a new geographical area poses an imminent threat. The infected plants showed floral virescence, phyllody, and stem fasciation (flattened stem). Floral malformation was very conspicuous with abnormal structures replacing normal flowers. All the floral parts, including petals, turned into green leaves. Total DNA was extracted from leaf mid veins of three symptomatic and three asymptomatic plants using a DNeasy Plant Mini Kit (Qiagen). PCR was carried out with the phytoplasma-specific universal P1/P7 primer set followed by nested primer pair R16F2n/R16R2 (2), resulting in DNA amplicons that were 1.8 kb and 1.2 kb, respectively, in all symptomatic samples tested. No amplification was observed with DNA from symptomless samples. This suggested association of a phytoplasma with the disease. The five purified nested PCR products were cloned in a pGEM-T Easy vector (Promega) and sequenced. One of the sequences that proved to be identical to the others was deposited in GenBank (Accession No. KJ417660). The consensus sequence was analyzed by NCBI BLAST and found to share 99% similarity with the 16Sr DNA sequence of the 'Candidatus Phytoplasma asteris' reference strain (GenBank HQ828108), which belongs to 16SrI group. The phylogenetic tree based on 16SrDNA sequence of phytoplasmas belonging to group 16SrI and other distinct phytoplasma groups also showed that the phytoplasma clustered with members of group 16SrI (3). The nested PCR product of R16F2n/R16R2 was digested using restriction enzymes AluI, BfaI, BstU, HhaI, HpaI, KpnI, MseI, and RsaI. The RFLP patterns were compared with those of known phytoplasma strains (2) and they matched the patterns for aster yellows subgroup B (16Sr I-B). Subsequently, the iPhyClassifier 16Sr group/subgroup classification based on similarity (4) analyses showed that the studied strain had 16SrDNA sequences in the 16SrI-B group with a similarity coefficient of 1.00. To the best of our knowledge, this is the first report of 16SrI-B phytoplasma associated with flax in India. References: (1) K. P. Akhtar et al. Phytoparasitica 41:383, 2013. (2) I. M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:337, 2004. (3) N. Saitou and M. Nei. Mol. Biol. Evol. 4:406, 1987. (4) Y. Zhao et al. Int. J. Syst. Evol. Microbiol. 59:2582, 2009.

Joint probability of shape and image similarities to retrieve 2D TRUS-MR slice correspondence for prostate biopsy

This paper presents a novel method to identify the 2D axial Magnetic Resonance (MR) slice from a pre-acquired MR prostate volume that closely corresponds to the 2D axial Transrectal Ultrasound (TRUS) slice obtained during prostate biopsy. The method combines both shape and image intensity information. The segmented prostate contours in both the imaging modalities are described by shape-context representations and matched using the Chi-square distance. Normalized mutual information and correlation coefficient between the TRUS and MR slices are computed to find image similarities. Finally, the joint probability values comprising shape and image similarities are used in a rule-based framework to provide the MR slice that closely resembles the TRUS slice acquired during the biopsy procedure. The method is evaluated for 20 patient datasets, of which 18 results match at least one of the two clinical expert choices.

Spectral clustering of shape and probability prior models for automatic prostate segmentation

Imaging artifacts in Transrectal Ultrasound (TRUS) images and inter-patient variations in prostate shape and size challenge computer-aided automatic or semi-automatic segmentation of the prostate. In this paper, we propose to use multiple mean parametric models derived from principal component analysis (PCA) of shape and posterior probability information to segment the prostate. In contrast to traditional statistical models of shape and intensity priors, we use posterior probability of the prostate region determined from random forest classification to build, initialize and propagate our model. Multiple mean models derived from spectral clustering of combined shape and appearance parameters ensure improvement in segmentation accuracies. The proposed method achieves mean Dice similarity coefficient (DSC) value of 0.96±0.01, with a mean segmentation time of 0.67±0.02 seconds when validated with 46 images from 23 datasets in a leave-one-patient-out validation framework.

High sensitivity (1 ppm) hydrogen detection using an unconventional Pd/n-InP Schottky device

Hydrogen is detected using a Pd/n-InP Schottky diode in which the elongated, very thin Pd electrode is of greater resistance than the underlying semiconductor substrate. Four-probe measurements of the device resistance, as a function of hydrogen concentration, are made by contacting only the Pd electrode, with a sensitivity of 1 ppm being achieved. On hydrogen exposure the device resistance drops from an initial high value, characteristic of the Pd electrode alone, to a lower value due to a hydrogen-induced lowering of the Schottky barrier that opens up the InP substrate as a parallel current carrying channel.