246 research outputs found
Selective Laser Sintering of Aluminum Extrusion Dies
In this study, geometric forms of maraging steel dies used in aluminum extrusion were optimized by means of flow dynamics as well as surface quality and mechanical properties of the final part. Maraging steel (MS1) dies were produced by Direct Metal Laser Sintering (DMLS), a Selective Laser Sintering (SLS) method, using EOS M290. Dies were not subjected to any conventional finishing post processes. Field tests were carried out in an industrial aluminum extrusion facility. Results presented that DMLS is a promising method for the production of dies with complex inner sections with high accuracy, high speed and low cost. Production of high quality extruded profiles was possible using additive manufactured dies directly from production without applying any finishing post process
Sustainable use of winter Durum wheat landraces under Mediterranean conditions
This research expected to determine new durum wheat germplasm resistant to biotic and abiotic stress factors. Eighty durum wheat lines selected from eighteen diverse landraces were tested together with eight durum wheat cultivars under reliable yellow rust epidemic during two successive years. Average infection coefficient of populations and cultivars was 32.44 in 2003 and 26.24 in 2004, showing severe epidemic condition which occurred at adult plant stage in 2003. Because of this the number of selected resistant and moderately resistant plant material greatly reduced. According to the yield trial study in which twenty resistant lines selected out of 30 resistant and moderately from sixteen populations were included, only two checks outperformed grand mean (2.48 t ha -1) and two lines selected from landrace population followed these with slightly lower yield difference. On the other hand, there were several lines which performed better than the grand mean of protein content (13.24%), SDS sedimentation (28.40 ml) and semolina color (24.35) and they ranked in the first group including the two checks cultivars. Bi- plot analysis showed that some promising lines with reasonable grain yields, good quality parameters, winter hardiness and drought tolerances among yellow rust resistance durum wheat landraces can be selected for semiarid conditions of Mediterranean countries for sustainable production
A microsatellite marker for yellow rust resistance in wheat
Bulk segregant analysis (BSA) was used to identify molecular markers associated with yellow rust disease resistance in wheat (Triticum aestivum L.). DNAs isolated from the selected yellow rust tolerant and susceptible F-2 individuals derived from a cross between yellow rust resistant and susceptible wheat genotypes were used to established a "tolerant" and a "susceptible" DNA pool. The BSA was then performed on these DNA pools using 230 markers that were previously mapped onto the individual wheat chromosomes. One of the SSR markers (Xgwm382) located on chromosome group 2 (A, B, D genomes) was present in the resistant parent and the resistant bulk but not in the susceptible parent and the susceptible bulk, suggesting that this marker is linked to a yellow rust resistance gene. The presence of Xgwm382 was also tested in 108 additional wheat genotypes differing in yellow rust resistance. This analysis showed that 81% of the wheat genotypes known to be yellow rust resistant had the Xgwm382 marker, further suggesting that the presence of this marker correlates with yellow rust resistance in diverse wheat germplasm. Therefore, Xgwm382 could be useful for marker assisted selection of yellow rust resistances genotypes in wheat breeding programs
Model Independent Evolution of Transverse Momentum Dependent Distribution Functions (TMDs) at NNLL
We discuss the evolution of the eight leading twist transverse momentum
dependent parton distribution functions, which turns out to be universal and
spin independent. By using the highest order perturbatively calculable
ingredients at our disposal, we perform the resummation of the large logarithms
that appear in the evolution kernel of transverse momentum distributions up to
next-to-next-to-leading logarithms (NNLL), thus obtaining an expression for the
kernel with highly reduced model dependence. Our results can also be obtained
using the standard CSS approach when a particular choice of the
prescription is used. In this sense, and while restricted to the perturbative
domain of applicability, we consider our results as a "prediction" of the
correct value of which is very close to . We
explore under which kinematical conditions the effects of the non-perturbative
region are negligible, and hence the evolution of transverse momentum
distributions can be applied in a model independent way. The application of the
kernel is illustrated by considering the unpolarized transverse momentum
dependent parton distribution function and the Sivers function.Comment: To appear in EPJC. 17 pages, 7 figure
Phenomenology of Non-Custodial Warped Models
We study the effect of bulk fermions on electroweak precision observables in
a recently proposed model with warped extra dimensions and no custodial
symmetry. We find that the top-quark mass, together with the corrections to the
Zbb vertex and the one-loop contribution to the T parameter, which is finite,
impose important constraints that single out a well defined region of parameter
space. New massive vector bosons can be as light as 1.5 TeV and have large
couplings to the t_R quark, and suppressed couplings to the t_L, b_L and
lighter quarks. We discuss the implications for searches of models with warped
extra dimensions at the LHC.Comment: Most relevant one-loop contributions to EWP observables included,
physics results partially changed. References added. 29 pages, 14 Figure
Oxidative stress in pregnancy and fertility pathologies
Oxidative stress designates the state of imbalance between reactive oxygen species (ROS) production and antioxidant levels. In a healthy placenta, there is an increase in ROS production, due to formation of new tissues and inherent metabolism, but this is balanced by higher levels of antioxidants. However, this balance is lost in some situations, with a consequent increase in oxidative stress levels. Oxidative stress has been implicated in several placental disorders and pregnancy pathologies. The present review intends to summarize what is known about the relationship between oxidative stress and well-known pregnancy disorders
Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis
Background: Interactions between mononuclear cells and activated pancreatic myofibroblasts (pancreatic stellate cells; PSC) may contribute to inflammation and fibrosis in chronic pancreatitis (CP). Methods: Markers of fibrosis and inflammation were concomitantly analysed by immunohistochemistry in chronic pancreatitis tissues. In vitro, PSC were stimulated with TNFalpha and LPS. Primary human blood mononuclear cells (PBMC) and PSC were cocultured, followed by analysis of cytokines and extracellular matrix (ECM) proteins. PBMC were derived from healthy donors and CP and septic shock patients. Results: In areas of mononuclear cell infiltration in chronic pancreatitis tissues, there was decreased immunoreactivity for collagen1 and fibronectin, in contrast to areas with sparse mononuclear cells, although PSC were detectable in both areas. LPS and TNFalpha induced collagen1 and fibronectin levels as well as the matrix degradation enzyme MMP-1. Coculture experiments with PSC and PBMC revealed increased fibronectin secretion induced by PBMC. In addition, donor and CP PBMC significantly induced an increase in IL-6, MCP-1 and TGFbeta levels under coculture conditions. Determination of the source of cytokines and ECM proteins by mRNA expression analysis confirmed PSC as major contributors of ECM production. The increase in cytokine expression was PBMC- and also PSC-derived. Conclusion: Mononuclear cells modulate the activity of pancreatic stellate cells, which may in turn promote fibrosis and inflammation
Warped Universal Extra Dimensions
We consider a 5D warped scenario with a KK-parity symmetry, where the
non-trivial warping arises from the dynamics that stabilizes the size of the
extra dimension. Generically, the lightest Kaluza-Klein (KK) particle is the
first excitation of the radion field, while the next-to-lightest Kaluza-Klein
particle is either the first excitation of the (RH) top quark or the first
KK-parity odd Higgs. All these masses are expected to be of order the
electroweak scale. We present simple analytical expressions for the masses and
wavefunctions of the lowest lying KK modes, and derive the Feynman rules
necessary for phenomenological applications. The framework allows to
interpolate between a strongly warped scenario a la Randall-Sundrum (RS), and a
weakly warped scenario that shares properties of both RS and Universal Extra
Dimensions models.Comment: 41 pages, 13 figures. Minor comments added. Published versio
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