Covalent functionalization of polyhedral graphitic particles synthesized by arc discharge from graphite.

Carbon materials including carbon nanoparticles, such as nanographite, graphene and graphenic materials, and carbon nanotubes are known to be highly hydrophobic. Oxidation treatments are widely used as the best methods to improve their affinity in a liquid medium or a polymer matrix so that they can be dispersed, handled and processed. Here, we have applied eight different oxidation treatments in order to graft oxygen-containing functional groups at the surface of polyhedral graphitic particles synthesized by arc discharge from graphite, also called astralenes. The used functionalization approaches include both standard chemical attack by strong oxidants and radical functionalization of the sp2 network by direct C[double bond, length as m-dash]C bond opening. Commonly efficient functionalization methods were unsuccessful to functionalize astralenes while radicals generated from arylhydrazine could lead to functionalization of the outer surface of astralenes. The occurrence of functionalization could be shown by TGA coupled with MS and XPS. The reported method represents the first example of functionalization of astralenes. The efficiency of the applied functionalization methods is discussed considering the chemical reactivity of different carbon nanomaterials including graphene and carbon nanotubes.

Diapause incidence and duration in the pest mango blossom gall midge, Procontarinia mangiferae (Felt), on Reunion Island.

The mango blossom gall midge, Procontarinia mangiferae, is a multivoltine species that induces galls in inflorescences and leaves of the mango tree, Mangifera indica. In subtropical Reunion Island, populations of P. mangiferae are observed all-year round, but the pattern and the role of dormancy in their life cycle have never been documented. We performed field and laboratory experiments using more than 15,000 larvae. We demonstrated that a larval diapause may affect a part of the midge population, regardless of the season. The total duration of the diapause varied from 6 weeks to more than 1 year. One year of field monitoring showed that the highest incidence of diapause was observed in larvae collected during the summer from mango leaves, where it affected approximately one-third of the individuals. This facultative diapause allows the permanent presence of P. mangiferae in the orchards. By recording diapause duration during 22 weeks under controlled conditions, we showed that high temperatures (26 °C) increased diapause duration and extended the range of the dates of diapause emergence, whereas cool temperatures (20 °C) shortened diapause duration and shortened the range of the dates of emergence from diapause. A temperature decrease from 26 to 20 °C triggered the emergence of diapausing individuals. These mechanisms ensure the synchronization of the emergence of diapausing individuals with the appearance of mango inflorescences, which is also induced by cool winter temperatures.

Inferior turbinate lateralization.

Inferior turbinate lateralization via an endonasal approach is a reliable low-risk procedure to correct inferior turbinate hypertrophy resistant to medical treatment. This well-established technique provides nasal comfort while conserving the mucosal membrane and physiology of the inferior turbinate, minimizing the postoperative complications (empty nose syndrome) besetting turbinoplasty involving mucosal or submucosal reduction.

Hydraulic and mechanical stem properties affect leaf-stem allometry in mango cultivars.

Leaf size-stem size allometric relationships are important features of biomass allocation in plants and are affected by biological functions linking the two organs. They have been studied at specific and supraspecific levels, but not at the infraspecific level. It was hypothesized that allometric relationships link leaf size and stem size at the cultivar level, and are cultivar-specific in relation to distinctive functional stem traits: hydraulic conductivity and mechanical strength. Allometric relationships between leaf size and stem size were established for 3 yr, using the standardized major axis method, on current-year branches, composed of one to 16 growth units, for four mango (Mangifera indica) cultivars characterized by contrasting growth habits. The hydraulic and mechanical stem properties of these cultivars were also measured. The slopes of the relationships were similar among cultivars, but not the y-intercepts. Different y-intercepts in the stem mass vs branch cross-sectional area relationship and in the leaf mass vs stem mass relationship were related to mechanical and to hydraulic stem properties, respectively. These results showed that leaf-stem allometry in mango cultivars was shaped by hydraulic and mechanical stem properties, supporting a functional interpretation of the relationship between leaf and stem dimensions.

Localized CVD growth of oriented and individual carbon nanotubes from nanoscaled dots prepared by lithographic sequences.

Using a combination of top-down lithographic techniques, isolated, individual and oriented multi-wall carbon nanotubes (MWNTs) were grown on nickel or iron nanoscaled dots. In the first step of the process, micron-sized catalytic metallic dots (either iron or nickel) were prepared using UV lithography. MWNTs were then synthesized from these catalysts using a direct current plasma-assistance and hot-filament-enhanced chemical vapor deposition (CVD) reactor. Samples were characterized by means of scanning electron microscopy. It turns out that the splitting up of the micron-sized dot is favored in the iron case and that the surface diffusion of the metal is enhanced using ammonia in the gaseous mixture during the CVD process. The results are discussed giving arguments for the understanding of the MWNT growth mechanism. In a second step, a focused ion beam (FIB) procedure is carried out in order to reduce the initial dot size down to submicronic scale and subsequently to grow one single MWNT per dot. It is found that nickel is most appropriate to control the size of the dot. Dots of size 200 nm +/- 40 nm are then required to grow individual MWNTs.

NEXAFS study of multi-walled carbon nanotubes functionalization with sulfonated poly(ether ether ketone) chains.

Functionalization of multi-walled carbon nanotubes (MWNTs) surface by sulfonated poly (ether ether ketone) SPEEK chains using a direct attachment reaction was investigated. A two step method was performed. MWNTs were oxidized by a nitric acid treatment to generate carboxyl groups on their surface. The grafting reaction of sulfonated groups of SPEEK with carboxyl groups present on the surface of oxidized MWNTs readily proceeds by using hexane diamine as an interlinking molecule. Transmission electron microscopy (TEM) shows that tubes are wrapped by polymer chains. Near edge X-ray absorption fine structure spectroscopy (NEXAFS) at the C K-edge, O K-edge, and N K-edge and X-ray photoelectron spectroscopy (XPS) were used to give evidence of covalent functionalization of MWNTs by SPEEK macromolecules.

Spectroscopic study of nitrogen doping of multi-walled carbon nanotubes.

Combined spatially resolved electron-energy loss spectroscopy (EELS) and high resolution near-edge X-ray absorption fine structure (NEXAFS) spectroscopy have been used to investigate the nitrogen doping of multi-walled carbon nanotubes (N-MWNT). EELS indicates that most of the tubes are nitrogen-doped. NEXAFS spectroscopy reveals pyridine-like and nitrile N structures. High resolution NEXAFS experiments show that the main nitrogen concentration originates from a high amount of molecular N2 encapsulated into only a small quantity of tubes.

A nucleation and growth model of vertically-oriented carbon nanofibers or nanotubes by plasma-enhanced catalytic chemical vapor deposition.

Carbon nanofibers are grown by direct current and hot filaments-activated catalytic chemical vapor deposition while varying the power of the hot filaments. Observations of these carbon nanofibers vertically oriented on a SiO2 (8 nm thick)/Si(100) substrate covered with Co nanoparticles (10-15 nm particle size) by Scanning Electron and Transmission Electron Microscopies show the presence of a graphitic "nest" either on the surface of the substrate or at the end of the specific nanofiber that does not encapsulate the catalytic particle. Strictly in our conditions, the activation by hot filaments is required to grow nanofibers with a C2H2 - H2 gas mixture, as large amounts of amorphous carbon cover the surface of the substrate without using hot filaments. From these observations as well as data of the literature, it is proposed that the nucleation of carbon nanofibers occurs through a complex process involving several steps: carbon concentration gradient starting from the catalytic carbon decomposition and diffusion from the surface of the catalytic nanoparticles exposed to the activated gas and promoted by energetic ionic species of the gas phase; subsequent graphitic condensation of a "nest" at the interface of the Co particle and substrate. The large concentration of highly reactive hydrogen radicals mainly provided by activation with hot filaments precludes further spreading out of this interfacial carbon nest over the entire surface of the substrate and thus selectively orientates the growth towards the condensation of graphene over facets that are perpendicular to the surface. Carbon nanofibers can then be grown within the well-known Vapor-Liquid-Solid process. Thus the effect of energetic ions and highly reactive neutrals like atomic hydrogen in the preferential etching of carbon on the edge of graphene shells and on the broadening of the carbon nanofiber is underlined.

[Comparison of the perception of esthetic and orthodontic treatment need between an African and a Caucasian population]. / Comparaison de la perception de l'esthetique et du besoin de traitement orthodontique entre des populations Africaine et Caucasienne.

INTRODUCTION: Improvement of dentofacial appearance is often the main motives of patient seeking orthodontic treatment. However perception of aesthetic and orthodontic treatment need may be different among populations of different cultural background. The aim of the present study was to compare the perception of aesthetic and orthodontic treatment need between Caucasian (French) and African (Senegalese) MATERIALS AND METHOD: In the present study the perception of the attractiveness of 98 colours photographs of dentitions were assessed by 34 Caucasian and 31 African lay judges by mean of a Power Point presentation. Each slide were displayed for evaluation during 20 seconds RESULTS: The two populations share the same perception of orthodontic aesthetic with respect to some occlusal traits. However they diverge in their appreciation of 70% of the dentitions with midline diastemas. There were also significant differences in the perception of orthodontic treatment need with the Caucasian judges suggesting treatment more often than Africans. CONCLUSION: The results are discussed in term of accessibility in orthodontic treatment in association with socioeconomic status.

Perfluoroctylbromide and hepatosplenic computed tomography. Preliminary clinical study.

The preliminary results of perfluorocytlbromide (PFOB) emulsion when used as an intravenous contrast agent for hepatosplenic CT imaging in humans are reported. Ten patients were examined using dosages ranging from 1 to 2 g/kg. There was good clinical and biochemical tolerance. Diagnostic dose for liver enhancement seems to be at least 2 g/kg, whereas 1 g/kg was sufficient for splenic enhancement.

Local lattice distortions in spherical carbon nanoparticles as studied by HRTEM image analysis.

The study of lattice distortions in structures with spherical or cylindrical geometry is of growing interest in the field of carbon nanoparticles (onions, nanotubes, etc.). We report an image analysis procedure entirely performed in reciprocal space which provides a global map of the inter-shell distances in carbon nanoparticles. This procedure is applied to carbon nanoparticles with a size of 100 nm that are generated under CVD conditions and exhibit positive as well as negative curvature of the basal lattice planes. These nanoparticles are subjected to intense electron irradiation under the beam of a high-voltage electron microscope with an acceleration voltage of 1.25 MeV. We observe a compression in their centre and a dilation of the outer shells. The reciprocal-space analysis of the high-resolution electron microscopy images opens the way to investigate the stability and equilibrium structure of carbon nanoparticles and to conclude on the formation mechanism.

Ni and Ni/Pt filling inside multiwalled carbon nanotubes.

Multiwalled carbon nanotubes are grown by microwave plasma chemical vapor deposition with CH4 and H2 as precursor gases. Ni and Ni/Pt electroplated layers are used as catalysts for the synthesis of the tubes. We observe that a very efficient filling of the tubes takes place with Ni. In some cases Ni/Pt filling is also observed inside the tubes. High-resolution transmission electron microscopy (HRTEM) studies, coupled with energy-dispersive X-ray analyses of the tubes, indicate Ni nanorods with a highly symmetrical cylindrical structure. The diameter of the cylindrical nanorods is on the order of 40 nm, and their length is 660 nm. The nano area diffraction pattern of the nanorods reveals the cubic structure of nickel, and electron diffraction spots corresponding to (111), (200), (220) planes are evident. The lattice constant of Ni measured from the diffraction spots was found to be 0.347 +/- 0.0013 nm. This should be compared with 0.352 nm, the value of "a" in bulk Ni. The decrease in the lattice constant may be due to the strain experienced inside the tubes. Raman spectroscopy shows the typical signature of the tangential breathing mode present in the tubes at 1580 cm-1 that shifts to a new position when the C12 is replaced by 13C. The shift, however, is too small and is difficult to explain on the basis of mass difference. HRTEM experiments indicate the presence of Ni3C in the samples dominantly in the interfacial region.

Non-renal urological lymphomas.

IVP, US and CT findings for 5 rare cases of non-renal lymphomas of the urinary tract are discussed. The 4 non-Hodgkin lymphomas (NHL) and 1 Hodgkin's disease (HD) involved the ureter (2 cases), bladder (2 cases) and renal pelvis (1 case). US and CT visualised the pyelic lesion (undetected by urography) as wall thickening and detected the two ureteral lesions (which were also revealed by antegrade pyelography for the 1 HD and by retrograde pyelography for an ureteral NHL). One bladder lesion was associated with a renal lesion (CT demonstrated retroperitoneal lymph nodes); the other was a multinodular form infiltrating the entire bladder.

[Comparison of echography and x-ray computed tomography in cancer of the ovary]. / Comparaison de l'échographie et de la scanographie dans les cancers de l'ovaire.

A retrospective study with an 18 month follow-up period was conducted on 184 patients (with 172 epithelial ovarian tumors) to compare the value of ultrasonography and CT for detection of pelvic masses, adenopathies, urinary stasis, hepatic metastasis and peritoneal or intestinal involvement. Ultrasound and CT findings were compared with histology data for 47 patients; ultrasound and CT data were compared with the clinical course for 53 patients. Ultrasonography was better than CT for the detection of pelvic masses, and was also slightly better for liver metastases and urinary stasis. CT was more effective for the diagnosis of lumbo-aortic and pelvic adenopathies, and peritoneal and intestinal involvement, but the sensitivity of imaging techniques remains insufficient for both of these lesion types. Combined examination by ultrasonography and CT every 6 months suffices for follow-up of patients who have undergone surgery and can evaluate tumoral response in patients treated by first-line chemotherapy.

Determination of antifungals in rodent diet by supercritical fluid extraction followed by packed column supercritical fluid chromatography with ultraviolet detection.

Supercritical fluid extraction (SFE) followed by packed column supercritical fluid chromatography with ultraviolet detection was evaluated as a quantitative method for determining 4 antifungals (fluconazole, tioconazole, hexaconazole, and UK-47,265) in rodent diet. Chromatography was achieved with a cyano-bonded silica column, UV detection at 210 nm, and methanol-modified supercritical carbon dioxide as mobile phase. The effects of modifier concentration, temperature, and column pressure on antifungal retention time was studied. Off-line SFE was optimized at 2 spike levels, ranging from 0.5 to 10 g/kg, for each of the 4 antifungals. Average recoveries ranged from 79.0% for UK-47,265 to 96.5% for hexaconazole. Overall, the procedure provides a suitable method for analyzing antifungals in spiked rodent diet.

[An obstetrical injury as the etiology of chronic corneal edema. Clinical study with scanning microscopy]. / Le traumatisme obstétrical, étiologie d'un oedème cornéen chronique. Etude clinique et en microscopie à balayage.

The case of a young woman with an unilateral corneal edema with regular folds of the descemet's membrane is reported. These lesions originate from an obstetrical traumatism by forceps and are associated with cutaneous scars of the temples. Scanning electron microscopy of the cornea shows multiple endothelial fissures; they are responsible for the late corneal decompensation.

[Imaging of renal metastases]. / Imagerie des métastases rénales.

Metastases are the most frequent malignant tumors of the kidney, but these lesions are of late onset in neoplastic disease. The 19 cases reported here were all investigated with various imaging techniques (CT 12 cases, ultrasonography 12 cases, urography 8 cases, angiography 2 cases, MRI 1 case). The most common primary malignancies were lung cancer, melanoma and cancer of the contralateral kidney. In this series, 8 of the lesions were solitary, and 9 were unilateral. Tumor vascularity was evaluated in 15 cases: 14 of these lesions were hypovascular. The differential diagnosis includes small cysts, lymphoma, bilateral renal cancer, multiple small abscesses and multiple small infarcts.

[Cavernous hemangioma of the spleen]. / Hémangiome caverneux de la rate.

A cavernous hemangioma of spleen in a clinically asymptomatic patient presented in the form of a hyperechogenic mass on ultrasound imaging, becoming progressively hyperdense on the CT scan with contrast. This appearance, similar in all respects to that seen with cavernous hemangioma of liver, is rarely reported in the literature.

[Mesenteric cysts in the adult]. / Kystes du mésentère de l'adulte.

The authors describe five cases of mesenteric cysts evaluated by ultrasonography and computed tomography: 3 cases of cystic lymphangioma, 1 vestigial serous cyst, 1 dermoid cyst. Ultrasonography is useful for analyzing the contents of these lesions, and must be utilized to search for possible pelvic anomalies, allowing diagnosis of pendunculated ovarian cysts for example. CT offers better sensitivity for evaluating the effect of such cysts on neighboring viscera and particularly on the intestine. CT is also better for identification of the fatty components indicative of dermoid or chylous cysts. These rare tumors are almost always benign, and a combined modality imaging approach based on ultrasound and CT suffices for diagnosis.

[Intra-abdominal hemangiopericytoma. Presentation of 5 cases and review of the literature]. / Hémangiopéricytome intra-abdominal. Présentation de 5 cas et revue de la littérature.

Intra-abdominal hemangiopericytomas are rare lesions, accounting of only 10% of all hemangiopericytomas. A total of five cases are reviewed: two malignant gastric lesions, two intraperitoneal malignancies, and one "benign" pancreatic lesion with a malignant hepatic recurrence. The images obtained by ultrasonographic and CT studies corresponded either to predominantly cystic or to solid lesions. Aside from the 50% of hemangiopericytomas that are malignant from the outset, the major problem with such lesions is the uncertain nature of their natural course.