Search results for "fragmentation"
showing 10 items of 798 documents
DNA damage and apoptosis in the mussel Mytilus galloprovincialis
2002
The effects of known genotoxic substances (4-nitroquinoline-N-oxide, benzo[a]pyrene, teniposide, etoposide, cycloheximide, tributyltin) on human cells (FLC, HL-60) and on mussels were investigated. The correlations between formation of DNA strand breaks and DNA fragmentation characteristic for the process of apoptosis were estimated. Strand breaks induced by 4-nitroquinoline-N-oxide and benzo[a]pyrene did not correlate with DNA fragmentation detected in the process of apoptosis. Induction of internucleosomal DNA fragmentation in HL-60 cells was initiated by teniposide, etoposide and tributyltin, while in the gills of mussels this was detected only with tributyltin. Levels of DNA strand brea…
Porphyrin-bile acid conjugates: from saccharide recognition in the solution to the selective cancer cell fluorescence detection.
2008
This paper describes the preparation and use of conjugates of porphyrins and bile acids as ligands to bind to tumor expressed saccharides. Bile acid-porphyrin conjugates were tested for recognition of saccharides that are typically present on malignant tumor cells. Fluorescence microscopy, in vitro PDT cell killing, and PDT of subcutaneous 4T1 mouse tumors is reported. High selectivity for saccharide cancer markers and cancer cells was observed. This in vivo and in vitro study demonstrated high potential use for these compounds in targeted photodynamic therapy.
Photodissociation of small group-11 metal cluster ions: Fragmentation pathways and photoabsorption cross sections
2003
Noble metal cluster ions Cu(n)(+), Ag(n)(+) and Au(n)(+) (n = 3-21) have been stored in a Penning trap and photodissociated by low intensity laser pulses of 10 ns at photon energies of 3.49 eV and 4.66 eV. The fragmentation pathways, neutral monomer and dimer evaporation, have been monitored as a function of cluster size, excitation energy and element. It is found that the behavior of the branching ratio between monomer and dimer evaporation as a function of excitation energy depends on the metal under investigation. In particular, the slope of the energy dependence is positive for silver but negative for gold and copper cluster ions. Furthermore, photoabsorption cross sections are determin…
Fragmentation pattern of gold clusters collided with xenon atoms
1994
Abstract The dissociation channels of gold cluster ions Au n + (2 ≤ n ≤ 23) have been investigated via collision induced dissociation in a Penning trap. Excited odd cluster ions with n ≤ 15 decay by evaporation of dimers, all others decay by monomer evaporation. Information on the binding energies is deduced from these dissociation channels.
Photo fragmentation of metal clusters stored in a penning trap
1996
Photo fragmentation studies of stored mass selected metal cluster ions of a large size range are reported. The experimental method and the data evaluation are described in detail. Gold cluster ions were produced by laser vaporization and stored in a Penning trap. After size selection they were electronically excited by irradiation with a pulsed laser beam. Relaxation by evaporation of neutral atoms and dimers was observed as a function of photon energy. From these data upper and lower limits for dissociation energies are determined for Aun + (n=3 to 23).
Comparing RADseq and microsatellites for estimating genetic diversity and relatedness : Implications for brown trout conservation
2019
The conservation and management of endangered species requires information on their genetic diversity, relatedness and population structure. The main genetic markers applied for these questions are microsatellites and single nucleotide polymorphisms (SNPs), the latter of which remain the more resource demanding approach in most cases. Here, we compare the performance of two approaches, SNPs obtained by restriction-site-associated DNA sequencing (RADseq) and 16 DNA microsatellite loci, for estimating genetic diversity, relatedness and genetic differentiation of three, small, geographically close wild brown trout (Salmo trutta) populations and a regionally used hatchery strain. The genetic di…
Activation of a caspase-3-independent mode of cell death associated with lysosomal destabilization in cultured human retinal pigment epithelial cells…
2008
International audience; Purpose: To characterize the possible cytotoxic effects of oxysterols (7-hydroxycholesterol (7-OH), 25-hydroxycholesterol (25-OH)) in human retinal pigment epithelial cells (ARPE-19) and to detail the relationships between some of these effects. Methods: ARPE-19 cells were treated with 7-OH and 25-OH. Cell viability was measured with the MTT assay. Membrane permeability, mitochondrial potential, and lysosomal integrity were measured by flow cytometry with propidium iodide, DiOC6(3), and acridine orange, respectively. Cell death was characterized by staining with Hoechst 33342, transmission electron microscopy, and analysis of the DNA fragmentation pattern. Caspase ac…
Short communication: Landscape and season effects on the diet of the Goshawk
2009
There are two general effects of habitat loss and frag-mentation of mature boreal forests (Schmiegelow &Monkkonen 2002). First, fragmentation by farmlandcreates stable structures such as permanent edge zoneswith enrichment of species diversity and density(Andren 1992, Berg & Part 1994). Secondly, modernforestry with clear-cuts creates sharp, unstable bound-aries between forest and open areas, usually with lesspronounced edge effects (Helle 1983, Schmiegelow &Monkkonen 2002). Considering the vast array of stud-ies on the effects of habitat loss and fragmentation onbird populations, relatively little attention has beenpaid to the role of predators, other than nest preda-tors, across different…
K− over K+ multiplicity ratio for kaons produced in DIS with a large fraction of the virtual-photon energy
2018
The K$^{-}$ over K$^{+}$ multiplicity ratio is measured in deep-inelastic scattering, for the first time for kaons carrying a large fraction $z$ of the virtual-photon energy. The data were obtained by the COMPASS collaboration using a 160 GeV muon beam and an isoscalar $^6$LiD target. The regime of deep-inelastic scattering is ensured by requiring $Q^2>1$ (GeV/$c)^2$ for the photon virtuality and $W>5$ GeV/$c^2$ for the invariant mass of the produced hadronic system. Kaons are identified in the momentum range from 12 GeV/$c$ to 40 GeV/$c$, thereby restricting the range in Bjorken-$x$ to $0.010.75$. For very large values of $z$, $i.e.$ $z>0.8$, we observe the kaon multiplicity ratio to fall …
Measurement of the azimuthal ordering of charged hadrons with the ATLAS detector
2012
This paper presents a study of the possible ordering of charged hadrons in the azimuthal angle relative to the beam axis in high-energy proton-proton collisions at the Large Hadron Collider (LHC). A spectral analysis of correlations between longitudinal and transverse components of the momentum of the charged hadrons, driven by the search for phenomena related to the structure of the QCD field, is performed. Data were recorded with the ATLAS detector at center-of-mass energies of √s=900 GeV and √s=7 TeV. The correlations measured in a kinematic region dominated by low-pT particles are not well described by conventional models of hadron production. The measured spectra show features consis…