On the ultrathin gold film used as buffer layer at the transparent conductive anode/organic electron donor interface

Previously, we have shown that a gold thin film of only 0.5 nm introduced at the interface between the indium tin oxide or ZnO anode and the organic electron donor in organic photovoltaic cells induces a strong improvement of the cell efficiency. Of course a thickness of 0.5 nm corresponds only to an averaged thickness, the films being too thin to be continuous. For a clear understanding of the physical mechanisms that are responsible for this improved behaviour, it is important to know the fractional coverage and the island height of this thin Au film. In the present work, we have used two different techniques, such as treated scanning electron microscope images and analysis of the inelastic part of peaks of X-ray photoelectron spectroscopy spectra, to estimate the gold coverage and island height of the transparent conductive anode. There is an excellent agreement between the results achieved by both methods. Only 15% of the anode is covered, which proves the high efficiency of gold as an anode buffer layer in organic photovoltaic devices

Impact des émissions atmosphériques industrielles (CO2) sur la qualité de l'air ambiant dans la région d'Arzew, Algérie

Les principaux objectifs étaient d'identifier la source et d'évaluer le niveau de pollution atmosphérique, conformément à la législation et aux normes nationales et internationales relatives à la qualité de l'air ambiant. Ce travail a porté sur l'impact des émissions de dioxyde de carbone (CO2) générées par les activités industrielles de raffinage du pétrole, de traitement du gaz naturel liquéfié et de pétrochimie, sur la qualité de l'air ambiant dans la région d'Arzew, Algérie en 2017. L'étude a révélé que la concentration annuelle moyenne de CO2 ne dépassait pas la valeur limite recommandée par la norme européenne EN 13779.  Cette étude a également démontré que les niveaux de teneur en CO2 dépendaient des taux d’émission industriels et des saisons météorologiques, atteignant leur maximum en été principalement à cause des conditions météorologiques relativement stables

Modélisation de la dispersion des émissions atmosphériques industrielles dans la région d'Arzew

L'audit environnemental est un processus qui évalue périodiquement la performance et la conformité des installations mis en place pour assurer la protection de l'environnement. Cette étude est menée dans le but d'évaluer l'impact de la dispersion des polluants atmosphériques tels que les NOx, PM10 et NH3 sur la qualité de l'air ambiant au niveau des sites industriels et des zones urbaines en 2017, 2018 et 2019, en utilisant le modèle ARIA IMPACT. Les résultats de la modélisation indiquent que le niveau de polluants étudiés en milieu urbains est bien supérieur à l'objectif de qualité de l'air ambiant conformément à la réglementation en vigueur, alors qu'en milieu industriel, l'air ambiant est considéré comme assez pollué en PM10 au niveau des sites industriels N°1 et N°2 et relativement pollué en NOx dans le site industriel N°1

Skull metastasis of hepatocellular carcinoma in normal liver: Case report

Background: So far hepatocellular carcinoma (HCC) is the most common liver malignant tumour; it is rarely encountered on a healthy liver (9). The metastasis from HCC cancer are seen in lymph nodes (16%–40%) and lungs (34%–70%), (1,3,4,5,7,8), bone metastasis is unusual and some locations stay rare among them the skull (2,4,5). We report here a case of a patient operated in our department for skull metastasis. That patient was followed for hepatocellular carcinoma in digestive surgery department. Case presentation: The patient is a 57 years old male presenting HCC on healthy liver, the patient was referred to our department by digestive surgery colleagues to manage a parietal subcutaneous mass; brain CT scans were performed objectified a calvarial osteolytic process. We remove the tumour and we put a cranioplasty using surgical cement, later the histological studies were in favour of secondary location of hepatocellular carcinoma. Conclusion: Skull metastasis from hepatocellular carcinoma is rare, reporting such cases strengthen the idea of evoking HCC metastasis in the differential diagnosis of cranial subcutaneous mass

Cu-Ag bi-layer films in dielectric/metal/dielectric transparent electrodes as ITO free electrode in organic photovoltaic devices

Among ITO alternative, dielectric/metal/dielectric multilayer structures are one of the most often studied possible substituent. However, if their optical and electrical properties are systematically investigated it is not the same with regard to their mechanical properties. In the present manuscript we have studied the properties of ZnS/Cu/Ag/ZnS, ZnS/Cu/Ag/MO3 (with M ¼ Mo or W) structures. With a maximum transmission of 90% and a sheet resistance of 5 U/sq the optimum structure exhibits a figure of merit of 82 10-3 Ω-1 when l = 600 nm. Beyond these standard measures we proceeded to the study of the mechanical properties of the multilayer structures. The inner and outer bending tests show that the ZnS/ Cu/Ag/ZnS (or MO3) structures are more flexible than ITO, while their responses to scotch tests show that they exhibit a large adhesion to the substrate, glass or plastic. The scratching adhesion test puts in evidence that the adhesion to the substrate of the Ag layer is smaller than that of ZnS/Cu/Ag/ZnS, which is smaller than that of ITO. On the other hand, this test shows that the ZnS/Cu/Ag/ZnS (no cracks for L = 25 N) is less brittle than ITO (cracks L = 15N). Finally, when used as anode in organic solar cells, the structure ZnS/Cu/Ag/WO3 allows achieving the best efficiency, similar to that obtained with ITO

Study of CuI thin films properties for application as anode buffer layer in organic solar cells

After chemico-physical characterization of CuI thin films, the structures indium tin oxide (ITO) /CuI are systematically studied. We show that the morphology of the 3 nm thick CuI film depends on its deposition rate. To obtain smooth homogeneous CuI film, it is necessary to depose it at 0.005 nm/s. After optimization of the deposition conditions of CuI, it is shown that it behaves like a template for the organic layer. For instance, when the organic film is copper-phthalocyanine, the molecules which are usually perpendicular to the plane of the substrate lie parallel to it when deposited onto CuI. In a same way, when the electron donor is a prophyrin derivative, CuI allows to double the power conversion efficiency of the cells based on the heterojunction porphyrin/C-60. When CuI is used as anode buffer layer, it increases systematically the short circuit current, the open circuit voltage, thus the efficiency of the organic solar cell. These effects are related, not only to the improvement of the band matching between the ITO and the electron donor, but also to the templating effect of the CuI. Moreover, we show that the beneficial effect of CuI. is effective, not only with ITO, but also with fluorine doped tin oxide

Improved performance of organic solar cells by growth optimization of MoO3/CuI double-anode buffer

We investigated the effect of a CuI anode buffer layer (ABL) on the molecular orientation of the copper phthalocyanine (CuPc) in organic photovoltaic cells (OPV cells), and we compare it to the effect of MoO3 buffer layer. While, in the presence of CuI, the CuPc molecules lie down parallel to the substrate, they stand up perpendicular in the case of MoO3. We show that the optical absorption, the morphology, and the JV characteristics of the OPV cells depends strongly on the orientation of the CuPc molecules. The improvement of the OPV cells performance is related to the property modifications induced by the change in molecule orientation. We show that the improvement of the OPV cell performance through the templating effect of CuI depends strongly on the deposition rate of the CuI, because the CuI thin-film morphology depends on this deposition rate. In this context, we show that the use of a double-ABL MoO3/CuI leads to a significant improvement of the cell performance. These results are discussed on the basis of the dual function of MoO3 and CuI. While both of them reduce the hole-injection barrier, CuI improves the CuPc film absorbance through specific molecular order and MoO3 prevents the OPV cells from leakage-path formation

Spinal epidural angiolipoma causing spinal cord compression: A case report

Background. Spinal angiolipoma (SAL) is a rare tumour with double component mature adipose tissue and proliferating abnormal blood vessels, which result in spinal cord compression requiring an urgent surgical removal. We report a case of woman with spinal angiolipoma. Case presentation. The patient is a 26 years old woman with past medical history of a low grade urothelial bladder carcinoma removed 4 months before she consults at our department, 2 months later the patient presented a lower limbs weakness. The clinical exam at the admission found a patient with paraparesis, hypoesthesia at the level of Th4 and urinary urgency. The spinal MRI objectified a spinal cord compression by a lesion located at the epidural space from Th2 to Th4. The patient was operated and a fatty well vascularized tumour distinct from the epidural fat was removed through a Th2 to Th4 laminectomy. The pathology study was in favour of an angiolipoma. Days after the operation the patient recovered totally, the weakness and the urinary urgency disappeared. The patient is flowed since 24 months she got pregnant. Conclusion. Spinal angiolipoma is a rare tumour with a clinic of spinal cord compression, MRI is the gold standard in diagnosis it shows a fatty lesion with a large enhancement, surgery is the perfect treatment with good outcome and exceptional recurrence

Dielectric/metal/dielectric alternative transparent electrode: observations on stability/degradation

The use of indium-free transparent conductive electrodes is of great interest for organic optoelectronic devices. Among the possible replacements for ITO, dielectric/metal/dielectric (D/M/D) multilayer structures have already proven to be quite efficient. One issue with organic devices is their lifetime, which depends not only on the organic molecules used but also on the electrodes. Therefore we study the variation, with elapsed time, of the electrical and optical properties of different D/M/D structures, with M  =  Ag or Cu/Ag. Six years after realization, it has been shown that if some structures retained an acceptable conductivity, some others became non-conductive. For a sample which remains conductive, in the case of a PET/MoO3/Ag/MoO3 multilayer structure, the sheet resistance changes from 5 Ω/sq–17 Ω/sq after six years. This evolution can be compared to that of a PET/ITO electrode that varies from 25 Ω/sq–900 Ω/sq after six years. It means that not only are the PET/MoO3/Ag/MoO3 multilayer structures more flexible than PET/ITO, but they can also be more stable. Nevertheless, if some PET/MoO3/Ag/MoO3 multilayer structures are quite stable, some others are not. This possible degradation appears to be caused primarily by the physical agglomeration of Ag, which can result in Ag film disruption. This Ag diffusion seems to be caused by humidity-induced degradation in these Ag-based D/M/D structures. Initially, defects begin to grow at a \u27nucleus\u27, usually a microscopic particle (or pinhole, etc), and then they spread radially outward to form a nearly circular pattern. For a critical density of such defects, the structure becomes non-conductive. Moreover the effect of humidity promotes Ag electrochemical reactions that produce Ag+ ions and enhances surface diffusivity with AgCl formation

A p21‐GFP zebrafish model of senescence for rapid testing of senolytics in vivo

Senescence drives the onset and severity of multiple ageing-associated diseases and frailty. As a result, there has been an increased interest in mechanistic studies and in the search for compounds targeting senescent cells, known as senolytics. Mammalian models are commonly used to test senolytics and generate functional and toxicity data at the level of organs and systems, yet this is expensive and time consuming. Zebrafish share high homology in genes associated with human ageing and disease. They can be genetically modified relatively easily. In larvae, most organs develop within 5 days of fertilisation and are transparent, which allows tracking of fluorescent cells in vivo in real time, testing drug off-target toxicity and assessment of cellular and phenotypic changes. Here, we have generated a transgenic zebrafish line that expresses green fluorescent protein (GFP) under the promoter of a key senescence marker, p21. We show an increase in p21:GFP+ cells in larvae following exposure to ionising radiation and with natural ageing. p21:GFP+ cells display other markers of senescence, including senescence-associated β-galactosidase and IL6. The observed increase in senescent cells following irradiation is associated with a reduction in the thickness of muscle fibres and mobility, two important ageing phenotypes. We also show that quercetin and dasatinib, two senolytics currently in clinical trials, reduce the number of p21:GFP+ cells, in a rapid 5-day assay. This model provides an important tool to study senescence in a living organism, allowing the rapid selection of senolytics before moving to more expensive and time-consuming mammalian systems