Search

The co-precipitation is successfully used for the synthesis of the hetero-junction CuO/ZnO. Thermal analysis, ATR spectroscopy and diffuse reflectance were used to assess the photoactivity of the hetero-system for the hydrogen formation upon visible light. As expected, the X-ray diffraction shows mixed phases of CuO (tenorite) and ZnO (Wurtzite). The specific surface area is around ~7 m2 g−1 with a crystallite size lying between 20 and 49 nm. The diffuse reflectance indicates an indirect transition at 3.13 eV for ZnO and a direct transition at 1.60 eV for the sensitizer CuO. The capacitance-potential (C−2 - E) characteristic of CuO plotted in Na2SO4 electrolyte exhibits p-type comportment with a flat band potential of −0.315 VRHE and a holes concentration of 8.7 × 1018cm−3. The Electrochemical Impedance Spectroscopy exhibits a semicircle characteristic of the bulk material with an impedance of 1725 Ω cm2 which decreases down to 453 Ω cm2 under irradiation, supporting the semiconducting character of CuO. ZnO mediates the electrons transport thanks to its conduction band, formed from Zn2+: 4s orbital (−0.92 VRHE); it is positioned cathodically with respect to the H2O/H2 level (~-0.74 VRHE), producing a H2 evolution under visible light illumination. The performance peaks at pH ~7 on 5% CuO/ZnO for a catalyst dose of 0.25 mg of catalyst/mL of solution in the presence of SO32− as holes scavenger. A liberation rate of 340 μmol h−1 (g of catalyst)−1 is obtained with a quantum efficiency of 0.38% under a photons flux of 2.09 × 1019 s−1.

MoO3 and 5% MoO3/ZnO were prepared by impregnation method using (NH4)6Mo7O24, 4H2O as precursor and ZnO as support. The prepared samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), infra red (FTIR) and UV-Vis diffuse reflectance (DRS) spectroscopies and photo-electrochemistry. The XRD pattern showed that the MoO3 powder treated at 700°C is a single-phase crystallizing in an orthorhombic structure with a direct optical transition (2.70 eV). The hetero-junction 5% MoO3/ZnO was photo-electrochemically characterized to assess its feasibility for H2 production under visible light. The capacitance potential (C-2 f(E)) characteristic of MoO3 plotted in Na2SO4, (0.1 M) electrolyte indicates n-type conduction with a flat band potential of -0.54 VSCE. The photocatalytic activity was performed for the photoreduction of water to hydrogen under visible light illumination. The best performance occurs at pH ~ 7 with an evolved volume of 5.9 mL.

The hetero-junction 5% CuO/ZnO elaborated by co-precipitation is studied by thermal analysis, X-ray diffraction, ATR spectroscopy, and optical reflectance to assess its performance for the H2 photoproduction. The specific surface area averages ~7 m2 g−1 while the crystallite size varies from 20 to 50 nm. The diffuse reflectance spectra shows an indirect transition at 3.13 eV for ZnO and a direct transition at 1.60 eV for CuO. The capacitance-potential plot of the sensitizer CuO exhibits p-type conduction, due copper deficiency, with a flat band potential of 0.075 VSCE. ZnO works as an electron bridge; its conduction band of ZnO (−0.68 VSCE) is cathodically localized with respect to that of CuO and CuOH2O/H2 level (~−0.5 VSCE), yielding H2 evolution under visible light illumination. H2 liberation rate of 340 µmol h−1 (g catalyst)−1 and a quantum yield of 0.38% were obtained under full light (27 mW cm−2) for a catalyst dose of 0.25 mg/mL and pH ~ 7 in presence of \({{\text{SO}}_{3}}^{2 - }\) as reducing agent; H2 liberation rate of 340 µmol h−1 (g catalyst)−1 and a quantum yield of 0.38% are determined.

Introduction: Prolactinomas are less frequent, but more invasive in males. Giant ones (≥4 cm) are extremely rare in literature. Their neurological, psychiatric and endocrine complications are life threatening. Our aim was to report the largest mono center series in order to analyze their frequency, their characteristics, and their complications. Subjects and Methods: All patients had clinical examination, hormonal, ophthalmological, and radiological assessment based on computed tomography scan and cerebral magnetic resonance imaging. Positive diagnosis was based on clinical symptoms, high prolactin ± immunohistochemy study. Mixed adenomas were excluded by hormonal exploration and immunohistochemy. For those who received medical treatment only, a reduction in tumor size was considered a supplementary positive point for the diagnosis. Results: Among 154 male prolactinomas seen between 1987 and 2013, we observed 44 giant tumors (28.5%). Median age = 36 years, and 38.3% were under 30. Median tumor height = 53.95 mm (40-130) and median prolactin = 15,715 ng/ml (n < 20). Solid and cystic aspect ± calcifications was observed in 25%. 42 had cavernous sinuses invasion. Other invasions were: Posterior= 65.9%, anterior= 63.6%, temporal= 15.9% and frontal = 9%. For endocrine complications: Hypogonadism = 98.4%, thyrotroph and corticotroph deficits were seen in respectively 34%, and 32%. Posterior pituitary insufficiency was observed in one case. For ophthalmological complications: Optic atrophy = 46%, Ptosis = 6.8%, diplopia/strabismus = 4.5%. Neurological complications were: Memory loss and/or unconsciousness = 18.2%, epilepsy = 15.9%, frontal syndrome = 9% and obstructive hydrocephalus = 6.8%. Conclusion: Giant prolactinomas account for 28% in our population. Severe neurological complications are frequent. But, obstructive hydrocephalus is rare, which argues for a slow progression.

Background: Suppurative meningitis (SM) or bacterial meningitis is a life-threatening condition, which is exceptionally due to pituitary tumors (PT). Our aim was to analyze its frequency among male macroprolactinomas (MPRL) deemed to be aggressive, to report the cases we observed in our practice and describe the circumstances under which SM appeared. Materials and Methods: We retrospectively analyzed 82 male MPRL in order to look for a history of well proved SM and the circumstances under which SM appeared. We also took into account the possibility of SM relapsing. Results: Four out of 82 male MPRL had SM = 4.87%. Three consulted for SM symptoms. SM was confirmed in Infectious Diseases department, but only one had rhinorrhea. Hormonal assessment and cerebral magnetic resonance imaging pleaded for aggressive prolactinomas. After antibiotics, SM was sterilized. Then, MPRL were treated with bromocriptine, which normalized prolactin and reduced PT. SM never relapsed. The 4 th case was hospitalized for a large multidirectional prolactinoma invading and/or arising from the skull base. He was operated on 3 times and then he was given Bromocriptine. After 3 months, he had rhinorrhea and then SM which was successfully treated by antibiotics. SM never relapsed after tumor reduction. Conclusion: SM was demonstrated in 4.87%. SM has revealed MPRL in 3 cases and appeared after bromocriptine intake in the 4 th one. Endocrinologists should be aware of this severe condition, which can be avoided by repairing as soon as possible the bony defect secondary to aggressive tumors, unless it is clogged by fibrosis: What probably happened in our cases.

We have carried out a calculation of the transmission coe cients per fission mode and determined the fission product yields for some nuclei using the Talys-0.72 version of the code(1). For fission, this code uses a statistical approach based on a revised version of the multi-modal random neck-rupture model (MM-RNRM). The fragment mass distribution is the sum of the three dominant fission modes: the superlong (SL), the standard I (ST I) and the standard II (ST II). The relative contribution of each mode is deduced from the calculation of the transmission coe cients according to the Hill-Wheeler expression taking into account the relevant transition states. The shell and pairing corrections are introduced in the level density parameter according to the Ignatyuk(2) formula. The calculated transmission coe cients values per fission mode are compared with the existing values. First, we reproduced the fragment mass distributions obtained using theTalys-0.64 version of the code for the fission of 238 U induced by 1.6 and 5.5 MeV neutrons with the 'constant temperature model' of Gilbert and Cameron(3), then we extended the calculations to other actinides with other level density models(4)(5). Finally, these calculated values of fission yields are compared with the experimental data.