Two-dimensional Dirac TiB2C2 as a potential anode material for Li-ion batteries: a first-principles study.

The development and design of anode materials with good stability, high capacity, low diffusion barrier and excellent cyclability is an important challenge for further improvement of the battery industry. In this context, a promising 2D anode material TiB2C2 with Dirac cone states is investigated through the first-principles prediction. We found this material to be thermodynamically, dynamically, and thermally stable, suggesting the possibility of its experimental synthesis. Considering its lightweight, planar structure and Dirac cone features, we systematically investigated the feasibility of the TiB2C2 monolayer as an anode material for Li-ion batteries (LIBs). Based on the adsorption energy of lithium on the monolayer surfaces, we determined the sites that can hold lithium ions with high adsorption energy. Moreover, TiB2C2 exhibits good ionic and electronic conductivity, a suitable voltage profile, and high structural stability upon the Li-loading process; it also shows 1.12% change in cell parameters. Importantly, a high storage capacity of up to 1075 mA h g-1 was found. All these criteria conclude the appealing electrochemical performance of the TiB2C2 monolayer as a promising anode material for LIBs.

Enhancement in photocatalytic water splitting using van der Waals heterostructure materials based on penta-layers.

Recently, van der Waals heterostructures (vdWHs) have been used to improve the performance of 2D materials, enabling more applications. By using first-principles calculations, we have studied the electronic and optical properties of vdWHs composed of penta-siligraphene and other penta-layers (p-Si2C4/p-X; X = Si2N4, ZnO2, Ge2C4 or SiGeC4). The stability of the vdWHs is verified by computing their binding energy, vibrational phonon spectra and ab initio molecular dynamics simulations. By assessing the electronic properties, we have found that the p-Si2C4/p-ZnO2, p-Si2C4/p-Ge2C4 and p-Si2C4/p-SiGeC4 vdWHs are semiconductors with an indirect band gap characterized by type-I band alignment. Meanwhile, the p-Si2C4/p-Si2N4 vdWH is a quasi-direct band gap semiconductor characterized by type-II band alignment. Bader charge analysis and charge density of p-Si2C4/p-Si2N4 vdWHs showed that photogenerated electrons move from the p-Si2N4 monolayer to the p-Si2C4 monolayer limiting the recombination of photogenerated charges and improving the photocatalytic efficiency. Furthermore, the p-Si2C4/p-Si2N4 vdWH exhibits suitable band edge positions compared to isolated monolayers suggesting its potential applicability in photocatalytic water splitting. The calculated optical absorption revealed that the p-Si2N4 monolayer exhibits substantial optical absorption in the ultraviolet (UV) range, while the p-Si2C4 monolayer and the p-Si2C4/p-Si2N4 vdWH show outstanding optical absorption on the order of 105 cm-1 in the visible and UV ranges. More importantly, the p-Si2C4/p-Si2N4 vdWH can greatly improve the optical absorption in these regions, which leads to high-efficiency usage of solar energy. Our study provides a route to design new vdWHs based on pentagonal monolayers, as well as an efficient photocatalyst for photocatalytic water splitting and optical devices.

[Complementary medicine in cancer patients under treatment in Marrakech, Morocco: a prospective study]. / Les médecines alternatives et complémentaires chez les patients cancéreux en cours de traitement à Marrakech, Maroc : étude prospective.

Use of complementary and alternative medicine (CAM) is very frequent in cancer patients. The aims of this study were to analyze the frequency, the reasons of use of CAM in patients with a cancer treated in a Moroccan oncology department. We included in this study 400 patients. An anonymous questionnaire was proposed to patients during treatment. Over 384 analyzable questionnaires, 71% of patients were using CAM. The most frequent method was religious therapy (60%). The second one was herbal medicine (36%). The main reason for using CAM was reducing psychic pain in 53%, and boosting the immune system in 32%. Adverse effects were reported in 2% of cases. Only 5% of patients discussed CAM with their doctors. The cost of CAM was less than 100 Euros in 88% of cases. To optimize the patient-physician relationship and to avoid a propensity to unproved treatments, accurate and adequate communication is necessary.

[Short and medium term cardiotoxicity of anthracyclins: a prospective study]. / Cardiotoxicité à court et à moyen terme des anthracyclines : étude prospective.

There is evidence that anthracyclins may affect the heart and ventricular function. This cardiac toxicity is frequent and serious. It is the first study in Morocco to investigate the frequency of anthracyclins cardiotoxicity. It has for objective to analyze the cardiotoxicity connected to anthracyclins, these risk factors as well as the echocardiographic parameters, which deteriorate prematurely. We led a forward-looking study between October 2008 and December 2009. With 90 patients followed in the service of oncology-radiotherapy and put under chemotherapy with anthracyclins. We conducted a study of various ultrasound parameters of cardiac function, before with anthracyclins, the third cure of chemotherapy, then in the 6th cure of treatment. Only 70 patients have been assessable. Average age was of 47 years (20-68 years); 91% were female. The cardiac function was preserved in 40% of the cases. Among our patients, 56% developed a decrease moderated in light of the cardiac function and 4% of cases developed a severe cardiotoxicity. The echocardiographic parameter most significant in our series was LVEF, followed by TEI index. We found a cardiotoxicity was strictly correlated with the cumulative dose, anthracyclins type and associated comorbidity. The anthracyclins cardiotoxicity is quite common in our series, which requires more thorough preventive measures including monitoring by echocardiography.

[Lymphoepithelial carcinoma of the conjunctiva: an unusual location]. / Carcinome lymphoépithélial de la conjonctive : une localisation exceptionnelle.

Lymphoepithelial carcinoma is an undifferentiated carcinoma associated with a lymphocytic infiltration and constitutes a rare category of malignant neoplasms that share morphologic features with undifferentiated nasopharyngeal carcinoma. Its pathogenic aspects remain unknown and it has been described at several sites, but it is rarely found in the conjunctiva. We report a case in a patient aged 66, revealed by a tumefaction of the internal angle of the left eye. The initial examination found a tumoral lesion in the medial canthus, extending to the medial half of the lower eyelid and a preauricular lymphadenopathy. Facial computed tomography scan showed that the lesion was responsible for an osteolysis of the medial wall of the left orbit. Histologic examination showed a proliferation of undifferentiated tumour cells with an intratumoral lymphocytic infiltrate. Immuno-histochemical evaluation led to a diagnosis of lymphoepithelial carcinoma (cytokeratin 7+, cytokeratin 20+, vimentin-). No Epstein-Barr viral genomic sequences were detected by in situ hybridization. Nasofibroscopy was normal. Treatment was a wide excision with enucleation, followed by 50 Gy external radiotherapy. After a follow-up period of 18 months, the patient was still in a situation of complete remission.