Exchange Process in the Dielectric Loss of Molecular and Macromolecular Ionic Conductors in the Interfacial Layers Formed by Electrode Polarization Effects.

Here we report a first analytical approach to determine the spectral dependence of the complex permittivity function of molecular and macromolecular ionic conductors in the interfacial layers formed by electrode polarization effects. We show that a previous model of electrode polarization effects that was successfully applied for describing the dielectric behavior of ionic liquids ( Serghei, A.; Tress, M.; Sangoro, J. R.; Kremer, F. Electrode polarization and charge transport at solid interfaces. Phys. Rev. B 2009 , 80 , 184301 ) can be now generalized and applied for polymer/ionic liquid blends as well as for poly(ionic liquid)s. The determined dielectric function of the interfacial layers reveals a dramatic change in the charge transport process manifested by a large decrease in conductivity. Our approach brings the first evidence for a relaxation peak detected in the dielectric loss of the interfaces, which is attributed to an exchange process between the interface and the bulk. This study gives new insights into the mechanism of charge transport at interfaces and could thus contribute to a better correlation between the dielectric properties of ion conducting materials and their electrochemical behavior at interfaces.

Onychomycosis: Which fungal species are involved? Experience of the Laboratory of Parasitology-Mycology of the Rabta Hospital of Tunis.

Onychomycosis is a fungal infection of nails caused by dermatophytes, yeasts or non-dermatophyte molds. The aim of our study was to describe the epidemiological features of onychomycoses encountered in the Tunis region. A retrospective study concerned 3458 cases of onychomycosis, confirmed by direct examination and/or a positive culture, was conducted in Parasitology - Mycology Laboratory, Rabta hospital, over a five-year period (2012-2016). Our patients were aged 1 to 85; more than half of the patients were aged over 60 years with a female predominance (67%). Toenail infections were most common, observed in 2702 cases (78%). Direct examination was positive in 3284 cases (95%), culture in 2409 cases (69.6%); these two examinations were positive simultaneously in 2235 cases (64.6%). The causative agents of these onychomycoses were dominated by the genus Candida in fingernails: Candida albicans (55.6%), Candida tropicalis (8.5%) and Candida parapsilosis (8.2%) were the most frequently incriminated species; while in toenail lesions, Trichophyton rubrum was by far the most frequently isolated species (96.8%). Our results join the literature; onychomycosis is a pathology of the adult, mainly candidosic etiology in hands and dermatophytic in feet.

Analytical model of secondary electron emission yield in electron beam irradiated insulators.

The study of secondary electron emission (SEE) yield as a function of the kinetic energy of the incident primary electron beam and its evolution with charge accumulation inside insulators is a source of valuable information (even though an indirect one) on charge transport and trapping phenomena. We will show that this evolution is essentially due, in plane geometry conditions (achieved using a defocused electron beam), to the electric field effect (due to the accumulation of trapped charges in the bulk) in the escape zone of secondary electrons and not to modifications of trapping cross sections, which only have side effects. We propose an analytical model including the main basic phenomena underlying the space charge dynamics. It will be observed that such a model makes it possible to reproduce both qualitatively and quantitatively the measurement of SEE evolution as well as to provide helpful indications concerning charge transport (more precisely, the ratios between the mobility and diffusion coefficient with the thermal velocity of the charge carrier).

Disseminated histoplasmosis diagnosed in the bone marrow of an HIV-infected patient: First case imported in Tunisia.

Histoplasmosis is a fungal infection caused by a dimorphic fungus, Histoplasma capsulatum. We report a first case of disseminated histoplasmosis in a 34-year-old woman, infected with human immunodeficiency virus (HIV), originating from Ivory Coast and living in Tunisia for 4 years. She was complaining from fever, chronic diarrhoea and pancytopenia. The Histoplasma capsulatum var. capsulatum was identified by direct microscopic examination of the bone marrow. She was treated by Amphotericin B, relayed by itraconazole. Even though a regression of symptoms and normalization of blood cell count (BCC), the patient died in a respiratory distress related to CMV hypoxemic pneumonia.

[Tinea capitis: Main mycosis child. Epidemiological study on 10years]. / Teignes du cuir chevelu : principale mycose de l'enfant. Étude épidémiologique sur 10 ans à Tunis.

Despite the changes in their epidemiology, and the improving level of hygiene of the population, tinea capitis is still considered a public health problem in our country, and is the most common type of dermatophytosis in our country. The aim of our study was to evaluate the epidemiological, clinical and mycological features of tinea capitis in children encountered in the Tunis region. A retrospective study concerned 1600 children aged 6 months to 15 years suspected to have tinea capitis was conducted in Parasitology-Mycology laboratory, Rabta hospital, over a 10-years period (2005-2014). Dermatophyte infections were confirmed using scalp scrapings examinated with direct microscopy using potash at 30% and/or culture on Sabouraud medium agar. Tinea capitis diagnosis was confirmed in 947 cases (59.18%). The sex ratio was 2.61 and the average age of 6.28 years with predominance in the age group of 4 to 8 years (52.27%). The most common clinical presentation was ringworm (87.65%). Ringworm large plaque was predominant (65.9%). Direct examination was positive in 884 cases (93.35%). Microsporic tinea was the most frequent (63.25%) followed by trichophytic tinea (29.78%). Positive cultures of dermatophytes were obtained in 912 cases (96.30%). The following dermatophyte species were isolated: Microsporum canis (67%), Trichophyton violaceum (31.68%), Trichophyton mentagrophytes (0.66%), Microsporum audouinii (0.22%), Trichophyton schoenleinii (0.22%) and Microsporum gypseum (0.22%). M. canis is currently the most frequently incriminated species in tinea capitis in Tunisia. This change is related to a change in behavior of our population, in fact the cat; main reservoir of M. canis cohabiting increasingly with Tunisian families.

Vulvovaginal candidiasis: Etiology, symptomatology and risk factors.

OBJECTIVE: To determine epidemiological, clinical and mycological characteristics of vulvovaginal candidiasis (VVC) in Tunisian population and to evaluate predisposing factors. PATIENTS AND METHODS: In this retrospective study, 2160 vaginal swabs were performed over 2 years (January 2014-December 2015). It was carried out at the laboratory of Parasitology and Mycology, Rabta Hospital in Tunisia. After swab collecting, direct examination and culture on Sabouraud Chloramphenicol and Sabouraud Chloramphenicol Actidione media were implemented to research yeasts. Then identifying of yeast species was through chlamydosporulation test and auxanogram. For each patient, a questionnaire was filled noting age, medical and surgical history, symptoms and risk factors. Statistical analysis of data was performed on SPSS 16 using Khi2 test, P<0.05 was considered significant. RESULTS: Direct examination was positive showed spore and/or pseudohypha in 24.72%. Candida albicans was isolated most frequently (76.61%) followed by Candida glabrata (17.18%). The maximum frequency of Candida-positive cultures was in 25-34 years old age group. Leucorrhea was the most common symptom (72.25%) followed by vulvar prurits (63.23%), dyspareunia (32.25%) and urinary burning (24.92%). Only pregnancy was correlated positively with VVC. CONCLUSION: It appears from our study that VVC is relatively common in Tunisia. His diagnosis results from confrontation of anamnestic, clinical and mycological data. The knowledge of risk factors and their correction would be necessary to prevent the occurrence of VVC, especially in its recurrent form.

Structure and reorientational dynamics of 1-F-adamantane.

The polymorphism and the dynamics of a simple rigid molecule (1-fluoro-adamantane) have been studied by means of X-ray powder diffraction and broadband dielectric spectroscopy. At temperatures below the melting point, the molecule forms an orientationally disordered Phase I with a cubic-centered structure (Phase I, Fm3¯m, Z = 4). This phase possesses eight equilibrium positions for the fluorine atom, with equal occupancy factors of 1/8. A solid-solid phase transition to a low-temperature tetragonal phase (Phase II, P4¯2(1)c, Z = 2) reduces the statistical disorder to only four possible equivalent sites for the fluorine atom, with fractional occupancies of 1/4. The dynamics has been rationalized under the constraints imposed by the space group of the crystal structure determined by powder X-ray diffraction. The dielectric spectroscopy study reveals that the statistical disorder in Phase II is dynamic in character and is associated with reorientational jumps along the two- and three-fold axes. In the dielectric loss spectra, the cooperative (α) relaxation exhibits a shoulder on the high-frequency side. This remarkable finding clearly reveals the existence of two intrinsic reorientational processes associated with the exchange of the F atom along the four sites. In addition to such "bimodal" relaxation, a secondary Johari-Goldstein relaxation is detected at lower temperatures.

Electrode polarization vs. Maxwell-Wagner-Sillars interfacial polarization in dielectric spectra of materials: Characteristic frequencies and scaling laws.

The characteristic frequencies of electrode polarization and of interfacial polarization effects in dielectric spectra of ionic liquids and of polymer bi-layers are determined and systematically analyzed, based on dielectric measurements by means of broadband dielectric spectroscopy, numerical simulations, and analytical calculations. It is shown that, to a large extent, identical scaling laws can be derived for these two dielectric phenomena taking place at external and internal interfaces. Surprisingly, a fundamentally different behavior concerning the interrelation between the characteristic frequencies is found. This brings direct evidence that different manifestations of the phenomenon of electrical polarization can be discriminated by examining the inter-relation governing their characteristic frequencies, which can be of significant importance in disseminating the nature of different contributions appearing in the dielectric spectra of complex materials. Based on our analysis, we derive a new formula, valid for both electrode polarization and interfacial polarization effects, that allows one to determine the conductivity value from the frequency position of the Maxwell-Wagner-Sillars peak. An excellent agreement between experiment and calculations is obtained. The formula can be used, furthermore, to estimate the thickness of the interfacial layers formed due to electrode polarization effects. Values in the order of several nanometers, increasing with decreasing temperature, are reported.

Effect of the sample annealing temperature and sample crystallographic orientation on the charge kinetics of MgO single crystals subjected to keV electron irradiation.

This paper focuses on the effect of sample annealing temperature and crystallographic orientation on the secondary electron yield of MgO during charging by a defocused electron beam irradiation. The experimental results show that there are two regimes during the charging process that are better identified by plotting the logarithm of the secondary electron emission yield, lnσ, as function of the total trapped charge in the material QT. The impact of the annealing temperature and crystallographic orientation on the evolution of lnσ is presented here. The slope of the asymptotic regime of the curve lnσ as function of QT, expressed in cm(2) per trapped charge, is probably linked to the elementary cross section of electron-hole recombination, σhole, which controls the trapping evolution in the reach of the stationary flow regime.

Polymorphisms of the NOS3 gene in Tunisian patients with Behçet's disease.

Behçet's disease (BD) is a multisystem inflammatory disease characterized by recurrent orogenital ulceration, ocular inflammation and skin lesions. Reduced plasma nitric oxide (NO) levels in patients with BD have been implicated in the development of the endothelial abnormalities and thrombotic complications occurring in these patients. Polymorphisms in the endothelial nitric oxide synthase gene (NOS3) have been inconsistently associated with BD. This inconsistency may derive from population stratification secondary to ethnic diversity, and consideration limited to only one rather than combinations of polymorphisms. We studied three genetic variations in the NOS3 gene: a single nucleotide polymorphism in the promoter region -786T>C, in exon 7 (Glu298Asp), and a variable number of tandem repeats in intron 4 (4a4b) of the NOS3 gene in 100 unrelated Tunisian patients with BD and 148 healthy controls. In addition, we also examined the association of NOS3 gene haplotypes with BD. Analyses of the Glu298Asp, -786T>C and 4a4b polymorphisms were made by the polymerase chain reaction (PCR) restriction fragment length polymorphism technique and PCR genotyping, respectively. The distribution of the Glu298Asp genotype differed significantly between patients with BD and controls (P = 0.01). Allele Asp298 was significantly more frequent in patients with BD than in controls (P = 0.005, OR = 1.70, 95% CI 1.14-2.54). In contrast, distribution of alleles and genotypes of -786T>C and 4a4b polymorphisms was not different between the control and BD group. However, the frequency of Asp-T-4b haplotype was significantly higher in patients with BD than in healthy controls. By gender, the signification remained only for heterozygous men (P = 0.03) and homozygous women (P = 0.02). These results suggest that Glu298Asp polymorphism of the NOS3 gene is associated with BD susceptibility in Tunisian patients.

Evaluation of the effective cross-sections for recombination and trapping in the case of pure spinel.

In this paper, we have investigated the evolution of the secondary electron emission in the case of pure spinel during electron irradiation, achieved in a scanning electron microscope at room temperature, which is derived from the measurement of the induced and the secondary electron currents. It was observed from the experimental results, that there are two regimes during the charging process: a plateau followed by a linear variation, which are better identified by plotting the logarithm of the secondary electron emission yield lnσ as function of the total surface density of trapped charges in the material QT . For positive charging, E0 = 1.1 and 5 keV, the slope of the linear part, whose value is of about 10(-10) cm(2) charge(-1), is independent of the primary electron energy. It is interpreted as a microscopic cross section for electron-hole recombination. For negative charging of pure spinel, E0 = 15 and 30 keV, the slope is associated with an electron trapping cross section close to 10(-14) cm(2) charge(-1), which can be assigned to the microscopic cross section for electron trapping. This trapping cross section is four orders of magnitude lower than the recombination one.

Effects of high vs. moderate exercise intensity during interval training on lipids and adiponectin levels in obese young females.

PURPOSE: We investigate the effects of 12-week interval training of moderate- or high-intensity exercise on blood lipids and plasma levels of adiponectin. METHODS: Thirty-four obese adolescent females [age = 15.9 ± 0.3 years; BMI and BMI-Z-score = 30.8 ± 1.6 kg/m(2) and 3 ± 0.3, respectively], were randomized to high-intensity interval training (HIIT, n = 11), moderate-intensity interval training (MIIT, n = 11), or a control group (CG, n = 12). Maximal oxygen uptake ([Formula: see text]), maximal aerobic speed (MAS), plasma lipids and adiponectin levels were measured in all subjects before and after training. RESULTS: Following the training program, in both training groups, body mass, BMI-Z-score, and percentage body fat (% BF) decreased, while [Formula: see text] and MAS increased. Low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and adiponectin levels were positively altered (-12.6 and -7.4 %; 6.3 and 8.0 %; 35.8 and 16.2 %; high to moderate training program, respectively). Waist circumference, triglyceride and total cholesterol decreased only in HIIT group (-3.5; -5.3 and -7.0 %, respectively, in all P < 0.05). Significant decrease in the usual index of insulin resistance (HOMA-IR) occurred in HIIT and MIIT groups (-29.2 ± 5.3 and -18.4 ± 8.6 %, respectively; P < 0.01). CONCLUSION: The results show that HIIT positively changes blood lipids and adiponectin variables in obese adolescent girls, resulting in improved insulin sensitivity, as attested by a lower HOMA-IR, and achieving better results compared to moderate-intensity exercise.

[Management of brain metastases from non-small cell lung carcinoma]. / Les métastases cérébrales des cancers bronchiques non à petites cellules : vers une prise en charge homogène.

INTRODUCTION: In France, approximately 30,000 new patients per year develop brain metastases (BM), most of them resulting from a lung cancer. STATE OF THE ART: Surgery and radiosurgery of all the BM must be considered when possible. In other cases, whole brain radiotherapy remains the standard of care. PERSPECTIVES: The role of chemotherapy, poorly investigated so far, should be revisited. CONCLUSION: This review focused on BM secondary to a non-small cell lung carcinoma.

[Medical treatment of nasopharyngeal cancers]. / Traitements médicaux des carcinomes du nasopharynx.

Nasopharyngeal cancers are essentially epidermoids (NPC) and dominated by the undifferentiated type (UCNT) in endemic areas. The standard treatment of NPC remain external beam radiotherapy but the results are poor in T3-4 lesions locally advanced (30-40% on event- free survival vs 80-90% in T1-T2) explained by a higher rate of relapse and metastases. Improvement of therapeutic results occurs with addition of chemotherapy to radiotherapy, specially with the concomitant scheme (weekly cisplatin), with an increase of overall and diseasefree survivals for the advanced stages (Meta-analysis data). Despite these progresses, we have to evaluate the risk of long term sequelae of combined therapies in children and adolescents. We are observing however an epidemiologic transition with the increase of more localized cases in term of T and N disease.

The G3057A LEPR polymorphism is associated with obesity in Tunisian women.

OBJECTIVES: The aim of this study was to evaluate the effect of the G3057A (rs62589000) LEPR polymorphism on obesity risk and plasma leptin, insulin, and lipid levels in a sample of the Tunisian population. DESIGN AND METHODS: Three hundred and ninety-three obese patients and 317 controls participated in this study. The G3057A genotype was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: In the entire study sample, no significant differences in genotype frequencies were observed between obese patients and controls. However, stratified analysis by gender revealed a quantitative increase in the variant allele (33.3% vs. 25.8%; χ(2)=4.90, p=0.026) in obese women (but not men) compared to controls. When a dominant model of inheritance was assumed, the GA+AA genotypes were more prevalent in these obese female patients than in controls (58.3% vs. 47.8%; χ(2)=4.08, p=0.044). Unconditional logistic regression showed that in women only, obesity risk was significantly higher for homozygotes for the variant allele (OR=2.73, 95% CI 1.03-7.21) and for carriers of GA+AA genotypes (OR=1.53, 95% CI 1.01-2.31) compared with homozygotes for the normal allele. The association between the G3057A LEPR variant and obesity remained statistically significant even after adjustment for age. No relationship was found between the G3057A LEPR polymorphism and leptin and insulin levels. Additionally, this LEPR gene variant had no effect on plasma lipid concentrations. CONCLUSION: There is evidence in this study that the G3057A LEPR polymorphism is associated with obesity in Tunisian women.

[Early breast cancer without axillary lymph node involvement]. / Cancer du sein sans atteinte ganglionnaire axillaire.

Breast cancer is the most common cancer in women. In France, breast cancer incidence was 88.9 per 100,000 women in 2000. Early detection of breast tumours by screening mammography allows a breast conserving treatment, i.e., breast irradiation preceded by a lumpectomy and a sentinel node biopsy. The standard irradiation of early breast cancers consists in delivering 50 Gy to the whole breast in 2 Gy fractions over a five-week period followed by an additional dose targeting the tumour bed of 16 Gy in eight fractions. The 3D-conformal treatment planning optimizes dose distribution to the whole breast and to the tumour bed and lessens the normal tissue irradiation (heart and ipsilateral lung). The aim of this article is to describe epidemiologic, radio anatomic and prognostic features of early stage breast cancer and to propose guidelines for 3D-conformal treatment planning in early breast cancers. This review is illustrated by a case report.

[Breast cancer with axillary lymph node involvement]. / Cancer du sein avec atteinte ganglionnaire axillaire.

Breast cancer is the most frequent cancer of women in western countries. There are one million new cases per year in the world which represents 22% of all female cancers, and more than 370,000 deaths due to breast cancer per year (14% of cancer mortality). More than half of breast cancers are associated with axillary nodal involvement. Post-operative radiation therapy (XRT) is a crucial part of locoregional treatment in axillary nodal involvement breast cancer owing to a 15-years risk reduction of locoregional recurrence of 70% and to a 5.4% risk reduction of specific mortality. In 3D-conformal irradiation in such breast cancers, target volumes are chest wall when mastectomy was performed or breast and boost of tumor bed in case of breast conservative surgery, and supra-clavicular and/or axillary and/or internal mammary node areas. The main organs at risk are ipsilateral lung, heart and brachial plexus. The aim of this article is to describe epidemiologic, radio anatomic and prognostic features of axillary nodal involvement breast cancer and to propose guidelines for 3D-conformal treatment planning in locally advanced breast cancers. This review is illustrated by a case report.