3D Imaging of a Dislocation Loop at the Onset of Plasticity in an Indented Nanocrystal.

Structural quality and stability of nanocrystals are fundamental problems that bear important consequences for the performances of small-scale devices. Indeed, at the nanoscale, their functional properties are largely influenced by elastic strain and depend critically on the presence of crystal defects. It is thus of prime importance to be able to monitor, by noninvasive means, the stability of the microstructure of nano-objects against external stimuli such as mechanical load. Here we demonstrate the potential of Bragg coherent diffraction imaging for such measurements, by imaging in 3D the evolution of the microstructure of a nanocrystal exposed to in situ mechanical loading. Not only could we observe the evolution of the internal strain field after successive loadings, but we also evidenced a transient microstructure hosting a stable dislocation loop. The latter is fully characterized from its characteristic displacement field. The mechanical behavior of this small crystal is clearly at odds with what happens in bulk materials where many dislocations interact. Moreover, this original in situ experiment opens interesting possibilities for the investigation of plastic deformation at the nanoscale.

Bubble dynamics in a pressure gradient with reentrant jet break through and energy loss.

The dynamics of a bubble in a pressure gradient is investigated experimentally and numerically with particular emphasis on the behavior at reentrant jet impact and break through the opposite side of the bubble with corresponding energy loss and vorticity generation. High speed photography observations of a bubble generated by electric spark energy deposit in a low ambient pressure tank are coupled with wavelet based Optical Flow Velocimetry (wOFV) and Boundary Element Method (BEM) numerical analysis to examine the flow field resulting from the reentrant jet formation and break through. We study, as an illustration, the effects of the constant pressure gradient due to gravity on the bubble dynamics. Energy losses between the first and second cycle are measured for the bubbles generated under various conditions characterized by a non-dimensional pressure gradient parameter, and the corresponding measured energy loss is used in the numerical simulations. Good correspondence is seen between the image analysis, the wOFV computations, and the BEM results and insight is gained on the involved physics.

[Synchronous sigmoid colon and breast cancers in man]. / Association synchrone d'un cancer du sigmoïde chez l'homme et d'un cancer du sein.

We report the case of 72-year-old man with sigmoid colon cancer associated with synchronous right breast cancer. However, in the present case, we found breast cancer insidiously at physical exam. The patient died after six months after the dissemination of the breast cancer.

[Value of US imaging following mastectomy]. / Intérêt de l'échographie systématique du site de mastectomie.

PURPOSE: To assess the value of US of the mastectomy site at the time of follow-up of the contralateral residual breast. MATERIALS AND METHODS: Over a 5 year period, 251 patients with previous mastectomy underwent 505 unilateral mammographies with US of the mastectomy site. The time delay between imaging and mastectomy ranged between 1-15 years, with a mean of 7.5 years. Lesions at the mastectomy site were classified as follows: BIRADS 2 for a cyst or prominent edema, BIRADS 3 for a lymph node with preserved fatty hilum or mildly echogenic cyst, BIRADS 4 for well-defined hypoechoic lesions, and BIRADS 5 for ill-defined lesions. RESULTS: None of the lesions classified as BIRADS 1, 2 or 3 was malignant. Eleven lesions were classified as BIRADS 4: 3 benign lesions, 7 malignant lesions, and 1 non-verified lesion. No lesion was classified as BIRADS 5. CONCLUSION: Systematic US evaluation of the mastectomy site appears warranted since only 1 of 7 malignant lesions was clinically palpable prior to US whereas all were retrospectively palpable after US.

Reactor for nano-focused x-ray diffraction and imaging under catalytic in situ conditions.

A reactor cell for in situ studies of individual catalyst nanoparticles or surfaces by nano-focused (coherent) x-ray diffraction has been developed. Catalytic reactions can be studied in flow mode in a pressure range of 10-2-103 mbar and temperatures up to 900 °C. This instrument bridges the pressure and materials gap at the same time within one experimental setup. It allows us to probe in situ the structure (e.g., shape, size, strain, faceting, composition, and defects) of individual nanoparticles using a nano-focused x-ray beam. Here, the setup was used to observe strain and facet evolution of individual model Pt catalysts during in situ experiments. It can be used for heating other (non-catalytically active) nanoparticles (e.g., nanowires) in inert or reactive gas atmospheres or vacuum as well.

Cavitation dynamics at microscale level.

Cavitation in a liquid is known for its deleterious effects, namely erosion, noise and loss of performance. In a mechanical heart valve, stresses generated by cavitation could lead to catastrophic failure. These deleterious effects are directly connected to the dynamics of pre-existing microscopic nuclei in the liquid medium. To highlight this, a selective review of the dynamics of the bubbles at the microscopic levels is considered here; the various aspects of the problem are highlighted and briefly addressed; new areas of research in non-spherical and bubble cloud dynamics are then considered. The importance of the inclusion of these collective and non-uniform flow effects in the dynamics of bubbles in a realistic cavitating flow field is also elucidated.

Scaling of mechanical heart valves for cavitation inception: observation and acoustic detection.

This paper discusses scaling laws of cavitation in mechanical heart valves based on analysis of leaflet operation and on hydrodynamic theory. It then suggests the laboratory use of large geometric scales and testing at low operating pressures to more easily investigate new heart valve designs. With such scaling, observations and measurements will become easier since the cavitation regions will be larger in dimension and the time scales will be increased due to reductions of bubble characteristic times and leaflet oscillation periods. The paper also discusses cavitation noise and the potential for acoustic detection of cavitation in a mechanical heart valve.

Effect of cavitation on pyrolytic carbon in vitro.

It has long been known that mechanical heart valves, when tested for durability using non-physiologic conditions common in accelerated testers, would cavitate. Until recently, cavitation was never observed in vivo. The discovery that a small number of Edwards-Duromedics heart valve explants indicated signs of cavitation erosion prompted a reassessment of the cavitation erosion potential of pyrolytic carbon (PyC). Analyses of the explanted valves indicated that cavitation may be accentuated by porous regions in the pyrolytic carbon coating from which most mechanical heart valves are constructed. Early studies have shown that for PyC (a) the resistance to cavitation erosion is comparable to that of aluminum, (b) the resistance to cavitation erosion is high initially, but with time the erosion rate accelerates, and (c) the cavitation erosion resistance is somewhat variable. In this study, similar experiments were performed utilizing polished pyrolytic carbon as well as microporous surfaces since microporous surfaces have been implicated as accelerating erosion. Within the accuracy of the measurement, we found no contributing acceleration due to the microporous nature of the pyrolytic carbon surfaces tested when compared to the polished surfaces. Examination of cross sections of samples exposed to cavitation conditions revealed the presence of extensive microcracking even without the presence of substantial surface erosion.

[Radiation-induced esophageal cancer. Presentation of a case and review of the literature]. / Cancer de l'oesophage radio-induit. Présentation d'un cas et revue de la littérature.

Esophageal cancer induced by radiation is uncommon. Irradiation of the head, the neck, the chest and the abdomen may cause an esophageal cancer several years later. Therefore, regular gastroscopy and biopsy of esophageal mucosa are strongly recommended in symptomatic patients. Surgery combined or not with radiotherapy seems to be the most effective treatment for this kind of cancer. We report a case of squamous cell carcinoma of the esophagus diagnosed 13 years after chemotherapy and radiotherapy for Hodgkin disease stade IIIb.

[Hodgkin's disease and pregnancy. 3 case reports and a review of the literature]. / Maladie de Hodgkin et grossesse. A propos de trois cas et revue de la littérature.

The association between Hodgkin's disease and pregnancy is rare. Hodgkin's disease does not affect the normal progress of the pregnancy nor of the fetus. Pre-therapy investigations of Hodgkin's disease have to be modified by pregnancy and in particular radiological examinations. Three are certain recommendations to be considered: termination of pregnancy is sometimes indicated in the first trimester but it does not have to be carried out routinely. Chemotherapy can be used in pregnancy as can radiotherapy if the disease is localised to the sub-diaphragmatic area.

[Gastric metastases of breast cancer]. / Métastases gastriques du cancer du sein.

Breast cancer is the most frequently encountered cancer in women and the first cause of death in the female population. Metastasis may occur ubiquitously depending on the histological type and the presence or absence of oestroprogesterone receptors. We report three cases with gastric metastasis. Signs of gastric involvement are often non-specific and should not be mistaken for simple side reactions to treatment. Hormone chemotherapy is indicated in most situations but surgery may be needed. It should be noted that gastrointestinal metastasis predominates in lobular breast cancers positive for progesterone receptors.

[Cerebral metastasis disclosing osteosarcoma. Apropos of a case]. / Métastase cérébrale révélatrice d'un ostéosarcome. A propos d'un cas.

Brain metastasis from osteosarcoma is a rare entity. Almost 20 cases have been reported in the literature. We report an illustrative case of a 15 years old boy presenting with isolated brain metastase revealing a fibular osteosarcoma. Diagnostic methods and treatment modalities are discussed.

[Castelman's disease. Report of two cases with review of the literature]. / Maladie de Castelman. Apropos de deux cas et revue de la littérature.

Castelman's disease, an unusual condition of unknown cause, consisting of a massive proliferation of lymphoid tissue. Three histologic variants (hyaline vascular, plasma-cell, and mixed) and two clinical types (localized and multicentric) of Castelman's disease have been described. Localized disease can be cured with surgery or radiotherapy, but complete remission in patients with multicentric disease have been achieved only with prednisone or chemotherapy given at the time of diagnosis. The aim of this study is to report two cases of retroperitoneal Castelman's disease with review of the literature. The first patient, of 36 years old, presented for abdominal pain with anorexia and weight loss. The abdomino-pelvic CT scan showed a 6 cm retroperitoneal mass. The biopsy of this lesion suspected a lymphoproliferative disease. At laparotomy total excision of mass was made and the final histology revealed a hyalino-vascular type of Castelman's disease. The second patient, of 26 years old, presented for left lombar pain with weight loss. The abdominopelvic CT Scan showed a 6.5 cm retroperitoneal mass. The biopsy of this lesion showed a Castelman's disease. At laparotomy total excision of mass was made and the final histology confirmed a hyalino-vascular type of Castelman's disease.

[Infections in cancer patients with granulocytopenia. Retrospective studies of 59 febrile episodes with hospitalization]. / Infections chez les cancéreux granulocytopéniques. Etudes rétrospectives de 59 épisodes fébriles hospitalisés.

A total of 59 febrile neutropenic episodes were retrospectively recorded at Hôtel-Dieu de France Hospital between August 1st 1991 and December 31st 1992. These episodes were recorded in 51 cancer patients. Median neutropenia was less than one week in 50% of the cases. The etiology of these fever was documented in 27 episodes (46%) and in 70% of the cases gram (-) rods were documented. B-Lactam and Aminoglycoside antibiotics were used in 34 episodes at the initial treatment of these patients. Success rate at this initial treatment or with a modification of the antibiotic therapy was recorded in 85% of the patients. Only 15% of the patients failed to this antibiotherapy, 2/3 of them had their disease in progression. The systemic use of Amphotericine E in those patients with prolonged febrile neutropenia and the concommitent use of growth factors in a sub-group of patients at high risk could lead to a higher success rate in these patients.

[Mesothelioma--asbestos in Lebanon: a problem to be considered]. / Mésothéliome--asbeste au Liban: un problème à retenir.

To estimate the incidence of pleural mesothelioma and its relationship with the occupational and environmental exposure to asbestos in Chekka region. Between 1991 and 2000, 22 cases of malignant mesothelioma were diagnosed at Hôtel-Dieu de France Hospital. Eighteen cases were epidemiologically investigated. Fifteen among these 18 patients (83%) had a positive exposure history: exposure was occupational in 11 cases and environmental in 4 cases. The tumor was attributable to Eternit Company in 12 cases among the exposed 15 (80%). These 12 cases were secondary to occupational exposures in 8 and to environmental exposure in 4 cases. Mean latency period between exposition and diagnosis was 29 years. Fifteen patients died from the progression of their disease after a median survival of 8 months. The relationship between pleural mesothelioma and Eternit Company with the related occupational and environmental risk in Chekka region is obvious. The assessment of the incidence needs a national cancer registry. Despite the protective measures taken by the government since 1996, an increase in the incidence is suspected in the coming ten years because of the long latency period of the disease.

Compact ultrahigh vacuum sample environments for x-ray nanobeam diffraction and imaging.

X-ray nanobeams present the opportunity to obtain structural insight in materials with small volumes or nanoscale heterogeneity. The effective spatial resolution of the information derived from nanobeam techniques depends on the stability and precision with which the relative position of the x-ray optics and sample can be controlled. Nanobeam techniques include diffraction, imaging, and coherent scattering, with applications throughout materials science and condensed matter physics. Sample positioning is a significant mechanical challenge for x-ray instrumentation providing vacuum or controlled gas environments at elevated temperatures. Such environments often have masses that are too large for nanopositioners capable of the required positional accuracy of the order of a small fraction of the x-ray spot size. Similarly, the need to place x-ray optics as close as 1 cm to the sample places a constraint on the overall size of the sample environment. We illustrate a solution to the mechanical challenge in which compact ion-pumped ultrahigh vacuum chambers with masses of 1-2 kg are integrated with nanopositioners. The overall size of the environment is sufficiently small to allow their use with zone-plate focusing optics. We describe the design of sample environments for elevated-temperature nanobeam diffraction experiments demonstrate in situ diffraction, reflectivity, and scanning nanobeam imaging of the ripening of Au crystallites on Si substrates.

Modelling single- and tandem-bubble dynamics between two parallel plates for biomedical applications.

Carefully timed tandem microbubbles have been shown to produce directional and targeted membrane poration of individual cells in microfluidic systems, which could be of use in ultrasound-mediated drug and gene delivery. This study aims at contributing to the understanding of the mechanisms at play in such an interaction. The dynamics of single and tandem microbubbles between two parallel plates is studied numerically and analytically. Comparisons are then made between the numerical results and the available experimental results. Numerically, assuming a potential flow, a three-dimensional boundary element method (BEM) is used to describe complex bubble deformations, jet formation, and bubble splitting. Analytically, compressibility and viscous boundary layer effects along the channel walls, neglected in the BEM model, are considered while shape of the bubble is not considered. Comparisons show that energy losses modify the bubble dynamics when the two approaches use identical initial conditions. The initial conditions in the boundary element method can be adjusted to recover the bubble period and maximum bubble volume when in an infinite medium. Using the same conditions enables the method to recover the full dynamics of single and tandem bubbles, including large deformations and fast re-entering jet formation. This method can be used as a design tool for future tandem-bubble sonoporation experiments.

Sequential FOLFOX-6 and gemcitabine for locally advanced and/or metastatic pancreatic cancer.

This prospective phase II trial aims to evaluate the sequential FOLFOX-6 and gemcitabine followed by adapted maintenance for advanced pancreatic cancer. Treatment included FOLFOX-6 for 4 cycles, followed sequentially by gemcitabine for 3 cycles. Patients, who show clinical benefit after both sequences, will receive maintenance treatment based on the investigator's discretion. From January 2005 to June 2008, 32 patients with median age of 63 were included; 75% of patients had metastatic disease, 81% had pure adenocarcinoma, while 19% had adenocarcinoma with a neuroendocrine component. There were 22% PR and 22% SD resulting in 44% tumor growth control. Under FOLFOX, grade 3/4 toxicities were neutropenia in 8 patients, thrombocytopenia and anemia in 3 patients each, and diarrhea in 2 patients. Under Gem, grade 3/4 neutropenia was observed in 4 patients, thrombocytopenia and anemia were observed in 2 patients, and hand-foot syndrome was observed in 3 patients. The median TTP and OS were 4 and 10 months, respectively. In APC, FOLFOX-6 regimen followed by gemcitabine achieved an interesting RR within a tolerable level of toxicity. This regimen seems to warrant further investigation to confirm its efficacy.

A phase II randomized study comparing navelbine and capecitabine (Navcap) followed either by Navcap or by weekly docetaxel in the first-line treatment of HER-2/neu negative metastatic breast cancer.

UNLABELLED: Following the proven efficacy and tolerability of Navcap and Navcap followed by docetaxel in the treatment of MBC, a phase II randomized study was initiated to assess the ORR of both arms in the first-line setting of MBC. Patients with no prior chemotherapy for MBC and HER-2/neu negative were eligible. All patients received Navcap (V 25 mg/m2 on d1 and d8 and C 825 mg/m2 bid D1-14 q3w) for a total of 4 cycles. Patients progressing under Navcap were withdrawn and received docetaxel as second-line treatment. Patients responding or stable were randomized to 2 arms: 4 cycles of Navcap (A) or 12 weekly docetaxel (25 mg/m²/week) (B). From July 2004 to July 2008, a total of 106 patients were enrolled. Ninety-four patients were evaluable before randomization, with a clinical benefit of 58%. Twenty-one patients (22%) had disease progression and were therefore not randomized. Forty-one patients were randomized to arm A and 29 patients to arm B. ORRs were 56 and 71% in arms A and B, respectively. The median time to progression and overall survival were 10 and 35 months in arm A and 12 and 37 months in arm B. Adverse events were mild. Arm A: grade 3-4 neutropenia (10%), grade 3 anemia (5%). Arm B: grade 3 neutropenia (6%), grade 3 anemia (6.2%), and grade 2 alopecia (12%). CONCLUSION: Both Navcap and Navcap followed by Docetaxel regimens were tolerated with manageable toxicity, offering consistent activities in terms of response rate for metastatic breast cancer patients.