Simulation of dielectrophoretic assembly of carbon nanotubes using 3D finite element analysis.

One of the most important methods for selective and repeatable assembly of carbon nanotubes (CNTs) is alternating current dielectrophoresis (DEP). This method has been demonstrated experimentally as a viable technique for nano-scale manufacturing of novel CNT based devices. Previous numerical analyses have studied the motion of nanotubes, the volume from which they are assembled, and the rate of assembly, but have been restricted by various simplifying assumptions. In this paper we present a method for simulating the motion and behavior of CNTs subjected to dielectrophoresis using a three-dimensional electrostatic finite element analysis. By including the CNT in the finite element model, we can accurately predict the effect of the CNT on the electric field and the resulting force distribution across the CNT can be determined. We have used this information to calculate the motion of CNTs assembling onto the electrodes, and show how they tend to move towards the center of an electrode and come into contact at highly skewed angles. Our analysis suggests that the CNTs move to the electrode gap only after initially contacting the electrodes. We have also developed a model of the elastic deformation of CNTs as they approach the electrodes demonstrating how the induced forces can significantly alter the CNT shape during assembly. These results show that the CNT does not behave as a rigid body when in close proximity to the electrodes. In the future this method can be applied to a variety of real electrode geometries on a case-by-case basis and will provide more detailed insight into the specific motion and assembly parameters necessary for effective DEP assembly.

What happens after participants complete a Union-MSF structured operational research training course?

SETTING: Eight operational research (OR) courses run by the International Union Against Tuberculosis and Lung Disease (The Union) and Médecins Sans Frontières (MSF) for participants from low- and middle-income countries. There is a knowledge gap about whether participants continue OR after course completion. OBJECTIVES: To determine 1) the research output of participants and their institutions after course completion; 2) the influence of OR fellowships on output; and 3) the output of non-OR fellows stratified by sex, region and staff position. DESIGN: A self-administered e-mail questionnaire survey. RESULTS: Of 83 participants who completed a course, 76 (92%) responded to the questionnaire. Following course completion, 47 (62%) participants completed new research projects, 38 (50%) published papers (vs. 25 [33%] who had published before the course), 42 (55%) presented posters or oral abstracts at conferences, 33 (43%) facilitated at further OR courses, 29 (38%) reviewed scientific papers, 25 (33%) secured further OR funding and 55 (72%) said their institutions were involved in OR implementation or capacity building. OR fellows performed better than non-OR fellows. Among the latter, males and participants from Asia had better output than females and participants from Africa (P < 0.05). CONCLUSION: The significant proportion of participants continuing to engage in OR after course completion provides encouraging evidence of the long-term value of this capacity building model.

Contexte : Huit cours de recherche opérationnelle (OR) structurée achevés de L'Union et Médecins sans Frontières pour des participants de pays à revenu faible ou intermédiaire. On ignore si les participants continuent à pratiquer la recherche opérationnelle après avoir suivi le cours.Objectifs : Déterminer 1) les activités de recherche des participants et de leurs institutions après la fin du cours ; 2) l'influence des bourses de recherche sur ces activités ; et 3) les activités des collègues n'ayant pas assisté au cours, stratifiées par sexe, région et statut professionnel.Schéma : Une enquête par questionnaire auto-administré envoyée par e-mail.Résultats : Sur 83 participants qui ont terminé le cours, 76 (92%) ont répondu au questionnaire. Après la fin du cours, 47 (62%) participants ont réalisé de nouveaux projets de recherche, 38 (50%) ont publié des articles (comparés à 25 [33%] qui en avaient publié avant le cours), 42 (55%) ont exposé des affiches ou présenté des résumés oraux lors de conférences, 33 (43%) ont été facilitateurs lors de cours suivants, 29 (38%) ont revu des articles scientifiques, 25 (33%) ont obtenu un financement ultérieur pour le recherche opérationnelle et 55 (72%) ont affirmé que leurs institutions étaient impliquées dans la mise en œuvre de recherche ou de renforcement des capacités. Les participants au cours ont eu une meilleure performance que les autres. Parmi ces derniers, les hommes et les participants venant d'Asie ont eu de meilleurs résultats que les femmes et les participants venant d'Afrique (P < 0,05).Conclusion : Une proportion significative de participants a continué à réaliser des recherches opérationnelles après la fin du cours. Ces constatations sont encourageantes en termes d'impact à long terme de ce modèle de renforcement des capacités.

Marco de referencia: La Unión Internacional Contra la Tuberculosis y Enfermedades Respiratorias y Médecins Sans Frontières realizaron en conjunto ocho cursos estructurados sobre investigación operativa, dirigidos a personas provenientes de países de ingresos bajos y medianos, pero no se cuenta con datos que permitan verificar si los participantes siguieron emprendiendo este tipo de investigaciones después de haber completado el curso.Objetivos: 1) Determinar la producción científica de los participantes y sus instituciones tras la compleción del curso; 2) definir la influencia que ejerció el hecho de haber recibido becas de investigación operativa sobre estos resultados; y 3) analizar la producción científica de los participantes que no recibieron becas en función del sexo, el continente de residencia y la categoría de su puesto en la institución.Método: Se llevó a cabo una encuesta autoadministrada difundida por correo electrónico.Resultados: De los 83 participantes que completaron el curso, 76 respondieron el cuestionario (92%). Después de haber completado la capacitación, 47 participantes finalizaron nuevos proyectos de investigación (62%), 38 publicaron artículos científicos (50%; en comparación con 25 autores antes del curso), 42 presentaron afiches o hicieron presentaciones orales en conferencias sobre su investigación (55%), 33 actuaron como facilitadores en cursos posteriores de investigación operativa (43%), 29 revisaron artículos científicos (38%), 25 lograron el financiamiento de nuevas investigaciones (33%) y 55 participantes afirmaron que sus instituciones participan en la ejecución de investigaciones operativas o en la formación de capacidad (72%). Los resultados de los participantes que recibieron becas fueron mejores que los resultados de las personas que no recibieron becas; de estos últimos, los participantes de sexo masculino y los provenientes de Asia exhibieron mejores resultados que las participantes de sexo femenino y los provenientes de África (P < 0,05).Conclusión: Una proporción notable de participantes a los cursos continuó su actividad en investigación operativa después de haber terminado la capacitación. Esta observación aporta pruebas alentadoras sobre la utilidad a largo plazo del presente modelo de creación de competencias.

The Union and Médecins Sans Frontières approach to operational research.

Operational research (OR) has become a hot topic at national meetings, international conferences and donor fora. The International Union Against Tuberculosis and Lung Disease (The Union) and Médecins Sans Frontières (MSF) Operational Centre Brussels strongly promote and implement OR with colleagues in low- and middle-income countries. Here we describe how the two organisations define OR, and explain the guiding principles and methodology that underpin the strategy for developing and expanding OR in those countries. We articulate The Union's and MSF's approach to supporting OR, highlighting the main synergies and differences. Then, using the Malawi National Tuberculosis Control Programme as an example, we show how OR can be embedded within tuberculosis control activities, leading to changes in policy and practice at the national level. We discuss the difficult, yet vitally important, issue of capacity building, and share our vision of a new paradigm of product-related training and performance-based OR fellowships as two ways of developing the necessary skills at country level to ensure research is actually performed. Finally, we highlight the need to consider and incorporate into practice the ethical components of OR. This is a key moment to be involved in OR. We are confident that in partnership with interested stakeholders, including the World Health Organization, we can stimulate the implementation of quality, relevant OR as an integral part of health service delivery that in turn will lead to better health for people, particularly for those living in the poorer parts of the world.

A case of endometrioid carcinoma of the fallopian tube mimicking an adnexal tumor of probable Wolffian origin.

We report a very uncommon case of endometrioid adenocarcinoma of the fallopian tube that mimicked, based on histology, a female adnexal tumor of probable Wolffian origin (FATPWO). We present our microscopic and immunohistochemical findings, and a review of the literature concerning these two entities. The differential diagnosis can be of great consequence, owing to the very different prognoses of the two tumors, and is based mainly on macroscopic appearance and immunohistochemical profile: epithelial membrane antigen (EMA) and CA125, generally lacking in FATPWO, are expressed in endometrioid adenocarcinoma, thus indicating the müllerian origin of this tumor.

Adenoid cystic carcinoma of the breast: utility of immunocytochemical study with collagen IV on fine-needle aspiration.

A case of adenoid cystic carcinoma (ACC) of the breast in a 71-year-old woman is reported. This neoplasm accounts for about 0.1% of all breast cancers. The mammography showed a well-delineated mass without calcifications. Cytologic examination of percutaneous fine-needle aspiration (FNA) material gave the diagnostic of ACC, which was confirmed by histologic examination. This report emphasizes the utility of immunocytochemical study with collagen IV antibody on FNA material of this uncommon tumor.

Papillary-cystic tumor of the pancreas.

A case of papillary cystic tumor (PCT) of the pancreas in a 40-yr-old woman is reported. This rare neoplasm was discovered fortuitously by a CT-scan examination for a palpable abdominal uterine leiomyoma. Percutaneous fine-needle aspiration (FNA) of the pancreatic mass was performed under CT-scan guidance. Cytologic examination of the material gave the diagnosis of PCT, which was confirmed by histologic examination of the resected tumor. Immunohistochemical staining showed a high degree of positivity to wide-spectrum anticytokeratin and anticytokeratin 20, and a weak positivity to anti-NSE antibody. In addition, the tumor cells were highly reactive for progesterone antibody, while they were negative for estrogen. These findings suggest a ductal origin for PCT, and also suggest that sex hormones may play a role in its growth, but not in its genesis. We emphasize the value of FNA cytologic features in the diagnosis of these rare tumors.