Kyste thymique cervical

Objectifs : Le kyste thymique est une tumeur congénitale rare. Souvent asymptomatique, elle atteint généralement les enfants âgés de moins de 10 ans. Siégeant au niveau du cou, cette tumeur pose essentiellement le problème de diagnostic différentiel clinique. Son traitement est chirurgical avec un excellent pronostic et un très faible risque de récidive locale. Nous rapportons un cas de kyste thymique cervical et nous rappelons la pathogénie et les diagnostics différentiels.Mots clés : kyste thymique, cou, histologiePurpose of study: The thymic cyst is a rare congenital tumor. Usually asymptomatic, this tumor is generally seen in childhood under the age of ten. In the neck, the preoperative diagnosis of this tumor is difficult and is rarely made. The treatment of choice is surgical excision. The long-term prognosis is excellent with a low rate of local recurrence. We report a new case of cervical thymic cyst and review the pathogenesis and the differential diagnosis.Keywords: Thymic cyst, neck, histology

Une etiologie rare d’une ulceration palatine : la sialometaplasie necrosante

La sialométaplasie nécrosante (SN) est une affection salivaire bénigne et rare, touchant principalement les glandes salivaires palatines et présentant des ressemblances cliniques et histologiques avec les carcinomes orales. Nous rapportons un cas de SN chez une patiente de 73 ans, non tarée, édentée, qui rapporte la notion de prothèse ancienne mal adaptée et qui présente une lésion ulcéro-végétante, bien limitée, douloureuse, palatine gauche, évoluant depuis 3 mois. Le scanner du massif facial a montré un épaississement des parties molles palatines avec un aspect aminci et irrégulier de l’os en regard. Une pathologie maligne à type de carcinome muco-épidermoide a été évoquée. Une exérèse radicale de la lésion a été réalisée et l’examen histologique a conclu à une SN.Mots clés : Sialométaplasie nécrosante; orale; palais; histologieNecrotizing sialometaplasia (NS) is a relatively uncommon benign disease of the salivary glands that most commonly occurs in the palate. It is often confused clinically and histopathologically with malignancies, such as squamous cell carcinoma or mucoepidermoid carcinoma. We report a case of NS in an edentate 73-year-old woman, with no medical history, showed up with a painful, well limited ulcerative lesion on the left palate, reporting its appearance three months ago. Reported also that she had a badly adapted removable denture. CT scan showed a thickening of the palate’s soft tissues with bone irregularity and thinning. A mucoepidermoid carcinoma was suspected. The patient underwent a radical excision of the lesion and histopathological diagnosis of NS was made.Keywords: Necrotizing sialometaplasia; oral; palate; histolog

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

Apolipoprotein E Genotypes in Alzheimer's Disease in Central Algerian Population

Background: Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder associated with cognitive decline and is the most common form of dementia in the elderly. Early-onset familial AD accounts for less than 1% of AD cases and develops before the age of 65 years because of mutations in either the APP gene or genes encoding presenilin 1 (PSEN1) or presenilin 2 (PSEN2). The majority of sporadic AD cases are referred to as late-onset AD (LOAD) because they occur late in life (>65 years). Apolipoprotein E (APOE) polymorphic alleles are the major genetic risk factor for AD. The human APOE gene exists as three polymorphic alleles, ε2, ε3, and ε4, with a worldwide frequency of 8%, 78%, and 13%, respectively, with ε4 reaching frequencies of 40% in AD patients. The purpose of this preliminary study was to determine ApoE genotype status since no previous association studies between LOAD and ApoE gene were available for the Central Algerian population. Methods: The cohort of our study was composed of 47 AD patients recruited from the Neurology Department of Frantz Fanon Hospital of Blida. Forty-seven controls with no type of dementia were also included in the study. All samples were genotyped for the ApoE Polymorphisms by PCR-RFLP method. Statistical studies can use the Fisher exact test or Chi-2 using the GraphPad Prism 7.0 software. Results: The results show that the genotype ɛ3/ɛ3 is most common in both groups followed by the heterozygous genotype ɛ3/ɛ4 which showed an increased frequency in patients compared to controls (27.66% vs. 12.77%, OR=3.66, IC=0.89-7.9, p=0,11). Although rare, all other possible genotypes have been observed in our cohort, namely ɛ2/ɛ2, ɛ2/ɛ3, ɛ2/ɛ4 and ɛ4/ɛ4. The ɛ2/ɛ4 genotype was observed only in AD patients, while the ɛ2/ɛ2 genotype was observed only in controls. As expected, the homozygous genotype ɛ4/ɛ4 was more frequent in AD patients, compared to controls (6.38% vs. 2.13%, respectively OR=2.64, IC=0.36-37.33; p=0,33). At the allelic level, ɛ4 allele was significantly associated with AD compared to controls (21,28% vs. 4,26% ; OR= 2.75, 95% CI= 1.109-6.35; p = 0.02, respectively), while the ɛ2 allele seems to be protective (4,26% vs. 9,57%, OR = 0.49 ; 95% CI=0.14-1.66 ; p=0,38, respectively), but without statistical significance. In population-based studies, the ApoEɛ4-AD association was weaker among African Americans (ε4/ε4, OR 5.7) and Hispanics (ε4/ε4, OR 2.2) and was stronger in the Japanese population (ε4/ε4, OR 33.1) compared with Caucasian cases (ε4/ε4, OR 12.5). The results obtained in our preliminary study indicate that the ApoEɛ4-AD association in the Central Algerian population is similar to that observed in the Mediterranean populations. Conclusion: We have presented, for the first time in the North Central Algerian population, the association of the ɛ4 allele with AD, which could be of great use in the diagnosis but also the follow-up of patients with this disease

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

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

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

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)