121 research outputs found

    The role of ras gene in the development of haemic neoplasia in Mytilus trossulus

    Get PDF
    Disseminated neoplasia has been reported in mussels (Mytilus spp) from numerous locations worldwide. This condition is progressive and fatal and the aetiology is unknown. In vertebrates, oncogenes such as ras, and tumour suppressor genes such as p53, play important roles in carcinogenesis. We have cloned a Mytilus trossulus homologue of the vertebrate ras gene, which shows conserved sequence in regions of functional importance. Neoplastic hemolymph samples derived from M. trossulus have been investigated for the presence of ras gene mutations and changes in expression

    Laparoscopic rectal resections: practical aspects

    Get PDF
    Abordul laparoscopic in chirurgia cancerului de rect este o considerat standardul de aur ce ofera rezultate oncologice similar cu o recuperare postoperatorie imbunatatita, si o rata minimala de complicatii. Pe fondul complexitatii crescute, cu toate astea, abordul laparoscopic ar trebui efectuat in centre tertiare, fiind rezervat chirurgilor cu o curba de invatare adecvata. O selectie atenta a cazurilor si o planificare adecvata ar trebui luata in considerare in cadrul acestui abord. Prezentarea de fata surprinde aspectele practice de baza precum si variatii tatice in cadrul rezectiilor de rect laparoscopice, precum si pasii potentiali in atingerea curbei de invatare.Laparoscopic approach is an already established procedure in rectal cancer which offers a similar oncological outcome, with improved postoperative recovery and fewer complications. Due to its increased complexity, however, the laparoscopic approach should be reserved for high-volume centers and for experienced surgeons with an adequate learning curve. Appropriate patient selection and planning must be carefully considered when opting for this approach. In this presentation, the primary practical aspects as well as certain tactical approaches will be covered regarding the laparoscopic rectal resections as well as the potential steps in achieving the learning curve

    Annual variation in the levels of transcripts of sex-specific genes in the mantle of the common mussel, Mytilus edulis

    Get PDF
    Mytilus species are used as sentinels for the assessment of environmental health but sex or stage in the reproduction cycle is rarely considered even though both parameters are likely to influence responses to pollution. We have validated the use of a qPCR assay for sex identification and related the levels of transcripts to the reproductive cycle. A temporal study of mantle of Mytilus edulis found transcripts of male-specific vitelline coat lysin (VCL) and female-specific vitelline envelope receptor for lysin (VERL) could identify sex over a complete year. The levels of VCL/VERL were proportional to the numbers of sperm/ova and are indicative of the stage of the reproductive cycle. Maximal levels of VCL and VERL were found in February 2009 declining to minima between July - August before increasing and re-attaining a peak in February 2010. Water temperature may influence these transitions since they coincide with minimal water temperature in February and maximal temperature in August. An identical pattern of variation was found for a cryptic female-specific transcript (H5) but a very different pattern was observed for oestrogen receptor 2 (ER2). ER2 varied in a sex-specific way with male > female for most of the cycle, with a female maxima in July and a male maxima in December. Using artificially spawned animals, the transcripts for VCL, VERL and H5 were shown to be present in gametes and thus their disappearance from mantle is indicative of spawning. VCL and VERL are present at equivalent levels in February and July-August but during gametogenesis (August to January) and spawning (March to June) VCL is present at lower relative amounts than VERL. This may indicate sex-specific control mechanisms for these processes and highlight a potential pressure point leading to reduced reproductive output if environmental factors cause asynchrony to gamete maturation or release

    Del Pezzo surfaces with 1/3(1,1) points

    Full text link
    We classify del Pezzo surfaces with 1/3(1,1) points in 29 qG-deformation families grouped into six unprojection cascades (this overlaps with work of Fujita and Yasutake), we tabulate their biregular invariants, we give good model constructions for surfaces in all families as degeneracy loci in rep quotient varieties and we prove that precisely 26 families admit qG-degenerations to toric surfaces. This work is part of a program to study mirror symmetry for orbifold del Pezzo surfaces.Comment: 42 pages. v2: model construction added of last remaining surface, minor corrections, minor changes to presentation, references adde

    Photoneutron measurements in the GDR region at ELI-NP

    Get PDF
    The Extreme Light Infrastructure - Nuclear Physics (ELI-NP) is a facility dedicated to nuclear physics research with extreme electromagnetic fields. The expected gamma-ray beams with energies up to 20 MeV, 0.5% relative energy resolution and similar to 10(8) photons per second intensity will allow precise photonuclear measurements. Nuclear structure experiments will involve photo-excitations of mainly low-spin collective states and the observation of the radiation emitted in the subsequent decays. Photoneutron reactions and elastic and inelastic photon scattering are proposed to be recorded using a mixed gamma-neutron detection system using LaBr3:Ce, CeBr3, BC501A and GS20 detectors. Photoneutron (gamma, xn) with x= 1,2 reactions cross sections measurements will be performed with a 4 pi flat efficiency neutron detection system dedicated for neutron multiplicity sorting experiments. The detection system is comprised of He-3 counters embedded in a moderator block. The paper will introduce the experimental setups dedicated to studies of the nuclear Giant Dipole Resonance excitation mode using the high energy resolution and high intensity ELI-NP gamma-ray beams. The feasibility studies performed using extensive Geant4 simulations, results of detector tests will be presented

    A 2022 τ\tau-Herculid meteor cluster from an airborne experiment: automated detection, characterization, and consequences for meteoroids

    Full text link
    Context. The existence of meteor clusters has long since been a subject of speculation and so far only seven events have been reported, among which two involve less than five meteors, and three were seen during the Leonid storms. Aims. The 1995 outburst of Comet 73P/Schwassmann-Wachmann was predicted to result in a meteor shower in May 2022. We detected the shower, proved this to be the result of this outburst, and detected another meteor cluster during the same observation mission. Methods. The {\tau}-Herculids meteor shower outburst on 31 May 2022 was continuously monitored for 4 hours during an airborne campaign. The video data were analyzed using a recently developed computer-vision processing chain for meteor real-time detection. Results. We report and characterize the detection of a meteor cluster involving 38 fragments, detected at 06:48 UT for a total duration of 11.3 s. The derived cumulative size frequency distribution index is relatively shallow: s = 3.1. Our open-source computer-vision processing chain (named FMDT) detects 100% of the meteors that a human eye is able to detect in the video. Classical automated motion detection assuming a static camera was not suitable for the stabilized camera setup because of residual motion. Conclusions. From all reported meteor clusters, we crudely estimate their occurrence to be less than one per million observed meteors. Low heliocentric distance enhances the probability of such meteoroid self-disruption in the interplanetary space.Comment: 6 pqges, 5 figure

    Moduli of ADHM Sheaves and Local Donaldson-Thomas Theory

    Full text link
    The ADHM construction establishes a one-to-one correspondence between framed torsion free sheaves on the projective plane and stable framed representations of a quiver with relations in the category of complex vector spaces. This paper studies the geometry of moduli spaces of representations of the same quiver with relations in the abelian category of coherent sheaves on a smooth complex projective curve XX. In particular it is proven that this moduli space is virtually smooth and related byrelative Beilinson spectral sequence to the curve counting construction via stable pairs of Pandharipande and Thomas. This yields a new conjectural construction for the local Donaldson-Thomas theory of curves as well as a natural higher rank generalization.Comment: 61 pages AMS Latex; v2: minor corrections, reference added; v3: some proofs corrected using the GIT construction of the moduli space due to A. Schmitt; main results unchanged; final version to appear in J. Geom. Phy

    The stringy instanton partition function

    Get PDF
    We perform an exact computation of the gauged linear sigma model associated to a D1-D5 brane system on a resolved A 1 singularity. This is accomplished via supersymmetric localization on the blown-up two-sphere. We show that in the blow-down limit the partition function reduces to the Nekrasov partition function evaluating the equivariant volume of the instanton moduli space. For finite radius we obtain a tower of world-sheet instanton corrections, that we identify with the equivariant Gromov-Witten invariants of the ADHM moduli space. We show that these corrections can be encoded in a deformation of the Seiberg-Witten prepotential. From the mathematical viewpoint, the D1-D5 system under study displays a twofold nature: the D1-branes viewpoint captures the equivariant quantum cohomology of the ADHM instanton moduli space in the Givental formalism, and the D5-branes viewpoint is related to higher rank equivariant Donaldson-Thomas invariants

    Identification of Reproduction-Specific Genes Associated with Maturation and Estrogen Exposure in a Marine Bivalve Mytilus edulis

    Get PDF
    Background: While it is established that vertebrate-like steroids, particularly estrogens (estradiol, estrone) and androgens (testosterone), are present in various tissues of molluscs, it is still unclear what role these play in reproductive endocrinology in such organisms. This is despite the significant commercial shellfishery interest in several bivalve species and their decline. Methodology/Principal Findings: Using suppression subtraction hybridisation of mussel gonad samples at two stages (early and mature) of gametogenesis and (in parallel) following controlled laboratory estrogen exposure, we isolate several differentially regulated genes including testis-specific kinases, vitelline lysin and envelope sequences. Conclusions: The differentially expressed mRNAs isolated provide evidence that mussels may be impacted by exogenous estrogen exposure
    corecore