Methods of Ga droplet consumption for improved GaAs nanowire solar cell efficiency.

We describe methods of Ga droplet consumption in Ga-assisted GaAs nanowires, and their impact on the crystal structure at the tip of nanowires. Droplets are consumed under different group V flux conditions and the resulting tip crystal structure is examined by transmission electron microscopy. The use of GaAsP marker layers provides insight into the behavior of the Ga droplet during different droplet consumption conditions. Lower group V droplet supersaturations lead to a pure zincblende stacking-fault-free tip crystal structure, which improved the performance of a nanowire-based photovoltaic device.

Unlocking doping and compositional profiles of nanowire ensembles using SIMS.

Dynamic and time-of-flight (TOF) secondary ion mass spectrometry (SIMS) was performed on vertically standing III-V nanowire ensembles embedded in Cyclotene polymer. By embedding the NWs in Cyclotene, the top surface of the sample was made planar, while the space between the NWs was filled to protect the background substrate from the ion beam, thus allowing for the NWs to be sputtered and analyzed evenly as a function of depth. Using thin film standards, SIMS analysis was used to calculate the impurity dopant concentration as a function of height in the NW ensemble. This marked the first use of conventional SIMS to accurately determine the doping density with excellent depth resolution. Additionally, this is the first presentation of SIMS as the only reported tool for characterizing the segment height uniformity of any arbitrary axial heterostructure NW ensemble.

Early determination of the reproductive number for vector-borne diseases: the case of dengue in Brazil.

OBJECTIVE: To evaluate a new method of deriving the reproductive number for vector-borne diseases from the early epidemic curves for vector-borne diseases with incubations in the vectors and in the hosts. METHOD: We applied the model to several dengue epidemics in different climatic regions of Brazil: Brasilia, Belém, Fortaleza, Boa Vista. RESULTS: The new method leads to higher estimates of the reproductive number than previous models. CONCLUSION: At present, Aedes aegypti densities, the meeting of more compatible strains of viruses and mosquitoes, may lead to re-emergence of urban yellow fever epidemics.

[Gynecologic laparoscopy and abdominal scars: what approach for the peritoneal cavity?]. / Coeliochirurgie gynécologique et ventre cicatriciel: quel abord de la cavité péritonéale?

To identify and discuss the advantages of the different methods of entry into the peritoneal cavity during gynecological laparascopy in patients who have previously undergone abdominal surgical procedures. Literature review comparing the strengths of each method of entering the peritoneal cavity during gynecological laparoscopic procedures. Adhesions increase the risks of access into peritoneal cavity during laparoscopy. Many techniques or safety rules have recently been described or re-evaluated as an alternative to using the traditional combination "Veress needle and blind introduction of the first trocar". The most relevant were the "open laparoscopy", the use of optical trocar, the double laparoscopy and the use of microlaparoscope. There remains no clear conclusion regarding the optimal form of laparoscopic entry in high risk patients. Relevant data emphasizes that critical to the surgeon's choice of technique is the immediate ability to recognize accidental injury and the capacity to avoid the scarred area. According to the literature review on the procedures used for entering the peritoneal cavity in high risk patients, we conclude that double laparoscopy may indeed be an underused procedure in such cases.

[Intra-arterial thrombolysis of acute mesenteric ischemia]. / Thrombolyse intra-artérielle d'une ischémie aiguë mésentérique.

A 73-year-old man with pre-existing cardiac failure, coronary artery and chronic obstructive pulmonary disease was presented for an acute mesenteric ischaemia, resulting from an embolic obstruction of the superior mesenteric artery. An intra-arterial fibrinolysis with a bolus of 250 000 units of streptokinase, followed by an infusion of 150 mg rtPA with adequate heparin dosage was performed 10 hours after the first symptoms. An abdominal guarding occurred 24 hours later, despite radiological improvement, justifying emergency surgery which confirmed the partial efficiency of the medical therapy. Unfortunately, a cardiogenic shock occurred preoperatively and the patient died five days later from intractable cardiovascular failure.