355 research outputs found
A radical approach to diverse meroterpenoids
Meroterpenoids are mixed terpenoidâpolyketide natural products with a variety of biological activities. Now, a synthetic approach that combines biocatalytic oxidation with a range of other radical-based reactions enables the divergent synthesis of eight oxidized meroterpenoid natural products and one analogue
The deformation of the interacting nucleon in the Skyrme model
Changes in the nucleon shape are investigated by letting the nucleon deform
under the strong interactions with another nucleon. The parameters of the axial
deformations are obtained by minimizing the static energy of the two nucleon
system at each internucleon distance . It is shown that the intrinsic
quadrupole moment of the interacting proton, , is about at
distances near fm.Comment: 11 pages, uudecode, gzip, tar, latex, 3 eps figures, accepted for the
publication by Phys.Lett.
Quenched Supersymmetry
We study the effects of quenching in Super-Yang-Mills theory. While
supersymmetry is broken, the lagrangian acquires a new flavour
symmetry. The anomaly structure thus differs from the unquenched case. We
derive the corresponding low-energy effective lagrangian. As a consequence, we
predict the mass splitting expected in numerical simulations for particles
belonging to the lowest-lying supermultiplet.Comment: LATTICE98(yukawa), minor change
A 3D in vitro model of the human breast duct:A method to unravel myoepithelial-luminal interactions in the progression of breast cancer
Abstract Background 3D modelling fulfils a critical role in research, allowing for complex cell behaviour and interactions to be studied in physiomimetic conditions. With tissue banks becoming established for a number of cancers, researchers now have access to primary patient cells, providing the perfect building blocks to recreate and interrogate intricate cellular systems in the laboratory. The ducts of the human breast are composed of an inner layer of luminal cells supported by an outer layer of myoepithelial cells. In early-stage ductal carcinoma in situ, cancerous luminal cells are confined to the ductal space by an intact myoepithelial layer. Understanding the relationship between myoepithelial and luminal cells in the development of cancer is critical for the development of new therapies and prognostic markers. This requires the generation of new models that allows for the manipulation of these two cell types in a physiological setting. Methods Using access to the Breast Cancer Now Tissue Bank, we isolated pure populations of myoepithelial and luminal cells from human reduction mammoplasty specimens and placed them into 2D culture. These cells were infected with lentiviral particles encoding either fluorescent proteins, to facilitate cell tracking, or an inducible human epidermal growth factor receptor 2 (HER2) expression construct. Myoepithelial and luminal cells were then recombined in collagen gels, and the resulting cellular structures were analysed by confocal microscopy. Resultï»żs Myoepithelial and luminal cells isolated from reduction mammoplasty specimens can be grown separately in 2D culture and retain their differentiated state. When recombined in collagen gels, these cells reform into physiologically reflective bilayer structures. Inducible expression of HER2 in the luminal compartment, once the bilayer has formed, leads to robust luminal filling, recapitulating ductal carcinoma in situ, and can be blocked with anti-HER2 therapies. Conclusions This model allows for the interaction between myoepithelial and luminal cells to be investigated in an in-vitro environment and paves the way to study early events in breast cancer development with the potential to act as a powerful drug discovery platform
Bag Formation in Quantum Hall Ferromagnets
Charged skyrmions or spin-textures in the quantum Hall ferromagnet at filling
factor nu=1 are reinvestigated using the Hartree-Fock method in the lowest
Landau level approximation. It is shown that the single Slater determinant with
the minimum energy in the unit charge sector is always of the hedgehog form. It
is observed that the magnetization vector's length deviates locally from unity,
i.e. a bag is formed which accommodates the excess charge. In terms of a
gradient expansion for extended spin-textures a novel O(3) type of effective
action is presented, which takes bag formation into account.Comment: 13 pages, 3 figure
State Of Charge estimation using Extended Kalman Filter in Electric Vehicles
Lithium-ion batteries are in the top priority among other batteries because of being safe, quick charging, and long-life cycle and are widely used in electric vehicles for having precise battery model, it is essential to decide factors like state of health and state of charge. In this paper using LA92 drive cycle experiment data is used for the state of charge estimation algorithm Firstly, for imitating the lithium-ion batterie's behavior in accurate way, a mathematical model of analogous battery is required. The 2RC branches are included in Thevenin model and Hybrid Pulse Power Characterization (HPPC) test data achieved at 40°C, 25°C, 10°C, 0°C, and -10°C is used to calculate the SOC 3-dimensional curve as a function of SOC and T. Coulomb counting (CC) and extended Kalman Filter method were observed for estimating the state of charge. The results show that EKF is more precise than CC (Coulomb Counting). The mistake of estimation with EKF is less than 1% that shows the reliability of the algorithm
Photon production in relativistic nuclear collisions at SPS and RHIC energies
Chiral Lagrangians are used to compute the production rate of photons from
the hadronic phase of relativistic nuclear collisions. Special attention is
paid to the role of the pseudovector a_1 meson. Calculations that include
reactions with strange mesons, hadronic form factors and vector spectral
densities consistent with dilepton production, as well as the emission from a
quark-gluon plasma and primordial nucleon-nucleon collisions, reproduce the
photon spectra measured at the Super Proton Synchrotron (SPS). Predictions for
the Relativistic Heavy Ion Collider (RHIC) are made.Comment: Work presented at the 26th annual Montreal-Rochester-Syracuse-Toronto
conference (MRST 2004) on high energy physics, Montreal, QC, Canada, 12-14
May 2004. 8 pages, 3 figure
Chiral Fluid Dynamics and Collapse of Vacuum Bubbles
We study the expansion dynamics of a quark-antiquark plasma droplet from an
initial state with restored chiral symmetry. The calculations are made within
the linear model scaled with an additional scalar field representing
the gluon condensate. We solve numerically the classical equations of motion
for the meson fields coupled to the fluid-dynamical equations for the plasma.
Strong space-time oscillations of the meson fields are observed in the course
of the chiral transition. A new phenomenon, the formation and collapse of
vacuum bubbles, is also predicted. The particle production due to the
bremsstrahlung of the meson fields is estimated.Comment: 12 pages Revtex,5 figures, Figures modified, minor changes in text.
To be published in Phys. Rev. Let
Effect of vaccination with a novel GnRH-based immunocontraceptive on immune responses and fertility in rats
1. As human-wildlife conflicts increase worldwide, novel methods are required for mitigating these conflicts. Fertility control, based on immunocontraceptives, has emerged as an alternative option to lethal methods for managing wildlife.
2. Immunocontraceptives are vaccines that generate an immune response to key components of an animal\u27s reproductive system. Some of these vaccines target the gonadotropin-releasing hormone (GnRH) and have been used successfully as contraceptives for many wildlife species. However, the need to capture animals for treatment limits the field applications of injectable vaccines. The availability of orally delivered immunocontraceptives would increase the breadth of applications of fertility control for wildlife management.
3. This study explored a new approach to developing an oral immunocontraceptive, exploiting the bioadhesive and immunologically active properties of killed Mycobacterium avium cell wall fragments (MAF). The MAF was conjugated to a GnRH recombinant protein called IMX294, used as a GnRH-specific immunogen.
4. An initial trial using the MAF-IMX294 conjugate provided the first evidence that an orally delivered immunocontraceptive vaccine could generate anti-GnRH antibody titres in laboratory rats.
5. Increasing the dose and frequency of vaccine administered to rats, in a second trial, enhanced the immune response, eliciting titres that reduced the proportion of females giving birth. This provided the first evidence of the contraceptive effect of an oral anti-GnRH vaccine.
6. Future work is required to further increase the immunogenic effect of the oral vaccine and to establish a dosing schedule that is effective for practical field applications
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