298 research outputs found
Genetic diversity and relationships in mulberry (genus Morus) as revealed by RAPD and ISSR marker assays
BACKGROUND: The genus Morus, known as mulberry, is a dioecious and cross-pollinating plant that is the sole food for the domesticated silkworm, Bombyx mori. Traditional methods using morphological traits for classification are largely unsuccessful in establishing the diversity and relationships among different mulberry species because of environmental influence on traits of interest. As a more robust alternative, PCR based marker assays including RAPD and ISSR were employed to study the genetic diversity and interrelationships among twelve domesticated and three wild mulberry species. RESULTS: RAPD analysis using 19 random primers generated 128 discrete markers ranging from 500â3000 bp in size. One-hundred-nineteen of these were polymorphic (92%), with an average of 6.26 markers per primer. Among these were a few putative species-specific amplification products which could be useful for germplasm classification and introgression studies. The ISSR analysis employed six anchored primers, 4 of which generated 93 polymorphic markers with an average of 23.25 markers per primer. Cluster analysis of RAPD and ISSR data using the WINBOOT package to calculate the Dice coefficient resulted into two clusters, one comprising polyploid wild species and the other with domesticated (mostly diploid) species. CONCLUSION: These results suggest that RAPD and ISSR markers are useful for mulberry genetic diversity analysis and germplasm characterization, and that putative species-specific markers may be obtained which can be converted to SCARs after further studies
Quark-antiquark potential in AdS at one loop
We derive an exact analytical expression for the one-loop partition function
of a string in AdS_5xS^5 background with world-surface ending on two
anti-parallel lines. All quantum fluctuations are shown to be governed by
integrable, single-gap Lame' operators. The first strong coupling correction to
the quark-antiquark potential, as defined in N=4 SYM, is derived as the sum of
known mathematical constants and a one-dimensional integral representation. Its
full numerical value can be given with arbitrary precision and confirms a
previous result.Comment: 16 pages. Typos corrected, minor change
Inter-diffusion of Plasmonic Metals and Phase Change Materials
This work investigates the problematic diffusion of metal atoms into phase
change chalcogenides, which can destroy resonances in photonic devices.
Interfaces between Ge2Sb2Te5 and metal layers were studied using X-ray
reflectivity (XRR) and reflectometry of metal-Ge2Sb2Te5 layered stacks. The
diffusion of metal atoms influences the crystallisation temperature and optical
properties of phase change materials. When Au, Ag, Al, W structures are
directly deposited on Ge2Sb2Te5 inter-diffusion occurs. Indeed, Au forms AuTe2
layers at the interface. Diffusion barrier layers, such as Si3N4 or stable
diffusionless plasmonic materials, such as TiN, can prevent the interfacial
damage. This work shows that the interfacial diffusion must be considered when
designing phase change material tuned photonic devices, and that TiN is the
most suitable plasmonic material to interface directly with Ge2Sb2Te5.Comment: 23 pages, 8 figures, articl
Antimetastatic Effects of Phyllanthus on Human Lung (A549) and Breast (MCF-7) Cancer Cell Lines
BACKGROUND: Current chemotherapeutic drugs kill cancer cells mainly by inducing apoptosis. However, they become ineffective once cancer cell has the ability to metastasize, hence the poor prognosis and high mortality rate. Therefore, the purpose of this study was to evaluate the antimetastatic potential of Phyllanthus (P. niruri, P. urinaria, P. watsonii, and P. amarus) on lung and breast carcinoma cells. METHODOLOGY/PRINCIPAL FINDINGS: Cytotoxicity of Phyllanthus plant extracts were first screened using the MTS reduction assay. They were shown to inhibit MCF-7 (breast carcinoma) and A549 (lung carcinoma) cells growth with IC(50) values ranging from 50-180 ”g/ml and 65-470 ”g/ml for methanolic and aqueous extracts respectively. In comparison, they have lower toxicity on normal cells with the cell viability percentage remaining above 50% when treated up to 1000 ”g/ml for both extracts. After determining the non-toxic effective dose, several antimetastasis assays were carried out and Phyllanthus extracts were shown to effectively reduce invasion, migration, and adhesion of both MCF-7 and A549 cells in a dose-dependent manner, at concentrations ranging from 20-200 ”g/ml for methanolic extracts and 50-500 ”g/ml for aqueous extracts. This was followed by an evaluation of the possible modes of cell death that occurred along with the antimetastatic activity. Phyllanthus was shown to be capable of inducing apoptosis in conjunction with its antimetastastic action, with more than three fold increase of caspases-3 and -7, the presence of DNA-fragmentation and TUNEL-positive cells. The ability of Phyllanthus to exert antimetastatic activities is mostly associated to the presence of polyphenol compounds in its extracts. CONCLUSIONS/SIGNIFICANCE: The presence of polyphenol compounds in the Phyllanthus plant is critically important in the inhibition of the invasion, migration, and adhesion of cancer cells, along with the involvement of apoptosis induction. Hence, Phyllanthus could be a valuable candidate in the treatment of metastatic cancers
Plasma-spray synthesis and characterization of ti-based nitride and oxide nanogranules
First measurement of the |t|-dependence of coherent J/Ï photonuclear production
The first measurement of the cross section for coherent J/Ï photoproduction as a function of |t|, the square of the momentum transferred between the incoming and outgoing target nucleus, is presented. The data were measured with the ALICE detector in ultra-peripheral PbâPb collisions at a centre-of-mass energy per nucleon pair sNN=5.02TeV with the J/Ï produced in the central rapidity region |y|<0.8, which corresponds to the small Bjorken-x range (0.3â1.4)Ă10â3.
The measured |t|-dependence is not described by computations based only on the Pb nuclear form factor, while the photonuclear cross section is better reproduced by models including shadowing according to the leading-twist approximation, or gluon-saturation effects from the impact-parameter dependent BalitskyâKovchegov equation. These new results are therefore a valid tool to constrain the relevant model parameters and to investigate the transverse gluonic structure at very low Bjorken-x.publishedVersio
First measurement of coherent Ï0 photoproduction in ultra-peripheral XeâXe collisions at âsNN = 5.44 TeV
The first measurement of the coherent photoproduction of Ï0 vector mesons in ultra-peripheral XeâXe collisions at sNN=5.44 TeV is presented. This result, together with previous HERA Îłp data and ÎłâPb measurements from ALICE, describes the atomic number (A) dependence of this process, which is particularly sensitive to nuclear shadowing effects and to the approach to the black-disc limit of QCD at a semi-hard scale. The cross section of the Xe+XeâÏ0+Xe+Xe process, measured at midrapidity through the decay channel Ï0âÏ+Ïâ, is found to be dÏ/dy=131.5±5.6(stat.)â16.9+17.5(syst.) mb. The ratio of the continuum to resonant contributions for the production of pion pairs is also measured. In addition, the fraction of events accompanied by electromagnetic dissociation of either one or both colliding nuclei is reported. The dependence on A of cross section for the coherent Ï0 photoproduction at a centre-of-mass energy per nucleon of the ÎłA system of WÎłA,n=65 GeV is found to be consistent with a power-law behaviour Ï(ÎłAâÏ0A)âAα with a slope α=0.96±0.02(syst.). This slope signals important shadowing effects, but it is still far from the behaviour expected in the black-disc limit.publishedVersio
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