153 research outputs found
Identification and differentiation of Ficus carica L. cultivars using inter simple sequence repeat markers
Information on germplasm diversity and relationships among elite materials is fundamentally important in crop improvement. The main objectives of our study is to determine the level of genetic diversity inter fig-tree cultivars using inter simple sequence repeat (ISSR) markers. Fifty-seven local Tunisian figtree cultivars were fingerprinted with ISSR marker. A total of 33 alleles were detected. A high level of genetic diversity was identified inter cultivars. The clustering grouped the studied cultivars into four clusters with no correlation to geographical origin
Decay of scalar variance in isotropic turbulence in a bounded domain
The decay of scalar variance in isotropic turbulence in a bounded domain is
investigated. Extending the study of Touil, Bertoglio and Shao (2002; Journal
of Turbulence, 03, 49) to the case of a passive scalar, the effect of the
finite size of the domain on the lengthscales of turbulent eddies and scalar
structures is studied by truncating the infrared range of the wavenumber
spectra. Analytical arguments based on a simple model for the spectral
distributions show that the decay exponent for the variance of scalar
fluctuations is proportional to the ratio of the Kolmogorov constant to the
Corrsin-Obukhov constant. This result is verified by closure calculations in
which the Corrsin-Obukhov constant is artificially varied. Large-eddy
simulations provide support to the results and give an estimation of the value
of the decay exponent and of the scalar to velocity time scale ratio
The decay of homogeneous anisotropic turbulence
We present the results of a numerical investigation of three-dimensional
decaying turbulence with statistically homogeneous and anisotropic initial
conditions. We show that at large times, in the inertial range of scales: (i)
isotropic velocity fluctuations decay self-similarly at an algebraic rate which
can be obtained by dimensional arguments; (ii) the ratio of anisotropic to
isotropic fluctuations of a given intensity falls off in time as a power law,
with an exponent approximately independent of the strength of the fluctuation;
(iii) the decay of anisotropic fluctuations is not self-similar, their
statistics becoming more and more intermittent as time elapses. We also
investigate the early stages of the decay. The different short-time behavior
observed in two experiments differing by the phase organization of their
initial conditions gives a new hunch on the degree of universality of
small-scale turbulence statistics, i.e. its independence of the conditions at
large scales.Comment: 9 pages, 17 figure
Benign osteoblastoma in an unusual mastoid location
SummaryIntroductionBenign osteoblastoma (OB) is an unusual primary bone tumor. The preferred locations are the posterior arch of vertebrae and long bones. We report herein an extremely rare location of an OB in the mastoid process of the temporal bone.Case reportA 22-year-old woman presented with painful left retro-auricular swelling. Computed tomography features were suggestive of an aggressive osteolytic lesion of the left mastoid. The pathologic examination of bone curettage material revealed a benign OB. A complete resection of the tumor was performed later, with no evidence of recurrence at 1 year.Discussion/ConclusionTo our knowledge, this is the 14th reported case of OB confined to the mastoid process of temporal bone. Its histological diagnosis can be difficult and osteosarcoma is its principal differential diagnosis. Although generally regarded as benign, OB has potential for recurrence and local invasion. As such, complete resection, whenever possible, is preferred over conventional curettage
Aerodynamic and Aeroacoustic Numerical Investigation of Turbofan Engines using Lattice Boltzmann Methods
International audienceIn recent years, lattice Boltzmann methods showed promising advantages over standard Navier-Stokes equation-based solvers. In this work, the capacity to predict both self noise and interaction noise is evaluated. First, a rod-airfoil interaction case is investigated, where the turbulence wake of the rod impinges the leading edge of the airfoil. Thereafter, a semi-infinite ducted axial fan is studied, where the turbulent boundary layers on each blades generate self noise which propagates into the duct, and radiates to the far-field. Subsequently, a ducted grid simulation is performed to verify the properties of the grid-generated turbulence. Finally, the grid and the axial-fan are combined within the same configuration, which comprises both self-noise and interaction noise. For each configuration, the agreements with experiments are satisfactory, however, acoustic propagation issues have been encounters from the duct intake to the free field. Nevertheless, the implemented wall model at the solid boundaries seems to correctly predict the acoustic sources on the blades
Synthesis, spectroscopic, and structural characterization of new functionalized gem-bisphosphonate complexes of tin(IV) chloride
The authors are grateful to the Tunisian Ministry of High Education and Scientific Research and Technology for financial support of this researchBisphosphonates of the types X(P(O)(OEt)2)2 (X = CH2=C (1a), CNCH2CH (1b) and PhCH2NCH2CH (1c)) react with SnCl4 in anhydrous dichloromethane to produce the new tin(IV) adducts [SnCl4(1a)] (2a), [SnCl4(1b)] (2b) and [SnCl4(1c)] (2c) in 72-80% yields. These complexes were characterized using IR, multinuclear (1H, 13C, 31P, 119Sn) NMR spectroscopy, elemental analysis, and in one case by single crystal X-ray diffraction. The NMR data show that the bisphosphonate ligands are coordinated to the tin center in a bidentate fashion forming cis octahedral tin complexes. Furthermore, the X-ray structure of complex 2b reveals that the bisphosphonate ligand is coordinated in a bidentate manner to the metal center in a distorted octahedral arrangement with Sn-O-P bond angles in the range 135.95(16)–137.99(18)°. The P=O and Sn-O bond lengths of 1.495(3)-1.497(3) and 2.134(3)-2.146(2) Å, respectively are in the order expected for phosphonate tin(IV) complexes. The results are discussed and compared with closely related analogues.PostprintPeer reviewe
Awareness of cognitive decline trajectories in asymptomatic individuals at risk for AD
Background: Lack of awareness of cognitive decline (ACD) is common in late-stage Alzheimer’s disease (AD). Recent studies showed that ACD can also be reduced in the early stages. Methods: We described different trends of evolution of ACD over 3 years in a cohort of memory-complainers and their association to amyloid burden and brain metabolism. We studied the impact of ACD at baseline on cognitive scores’ evolution and the association between longitudinal changes in ACD and in cognitive score. Results: 76.8% of subjects constantly had an accurate ACD (reference class). 18.95% showed a steadily heightened ACD and were comparable to those with accurate ACD in terms of demographic characteristics and AD biomarkers. 4.25% constantly showed low ACD, had significantly higher amyloid burden than the reference class, and were mostly men. We found no overall effect of baseline ACD on cognitive scores’ evolution and no association between longitudinal changes in ACD and in cognitive scores. Conclusions: ACD begins to decrease during the preclinical phase in a group of individuals, who are of great interest and need to be further characterized. Trial registration: The present study was conducted as part of the INSIGHT-PreAD study. The identification number of INSIGHT-PreAD study (ID-RCB) is 2012-A01731-42
Characterization of the inflammatory cell infiltrate and expression of costimulatory molecules in chronic echinococcus granulosus infection of the human liver
Background: The local immune responses to chronic echinococcal infections in various organs are largely unknown. Since the liver is the most frequently involved organ in such infections in human we aimed to characterize the inflammatory as well as immune cell infiltrate around hydatid cysts in the liver and compared to common inflammatory processes of the liver. Method: Surgical samples from the liver of 21 cystic echinococcosis (CE) patients were studied and the distribution of different types of inflammatory and immune cells were determined by immunohistochemistry. Furthermore, expression levels of costimulatory CTLA4, CD28, CD80 and CD86 molecules were measured at RNA level by PCR. Liver biopsy samples from patients with steatohepatitis (SH, n = 11) and chronic hepatitis (CH, n = 11) were used as non-inflammatory and chronic inflammatory controls, respectively. The composition and density of the inflammatory and immune cell infiltrates have been compared by using morphometry. Results: CD3+ T cells predominated the inflammatory infiltrate in all pathological processes, while in CE samples CD20+ B cells, in CH samples CD68+ macrophages were also frequent. Both myeloperoxidase (MPO) + leukocytes and CD68+ macrophages were found to be significantly decreased in CE as compared to either SH or CH samples. Concerning T cell subtypes, only CD8+ T cells were found to be significantly decreased in SH samples. CD1a + dendritic cells were almost completely missing from CE biopsies unlike in any other sample types. There were no differences detected in the mRNA expression of costimulatory molecules except decreased expression of CD28 in CE samples. Conclusion: In the hydatid lesions of the liver of chronic echinococcal infections T cell-mediated immunity seems to be impaired as compared to other types of chronic inflammatory processes, suggesting an immunosuppressive role for Echinococcus granulosus, which deserve further attentions
Low Cognitive Awareness, but Not Complaint, is a Good Marker of Preclinical Alzheimer's Disease
Subjective cognitive decline (SCD) may result from many conditions, including Alzheimer's disease (AD)
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