Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots.

We report Coulomb mediated hybridization of excitonic states in optically active InGaAs quantum dot molecules. By probing the optical response of an individual quantum dot molecule as a function of the static electric field applied along the molecular axis, we observe unexpected avoided level crossings that do not arise from the dominant single-particle tunnel coupling. We identify a new few-particle coupling mechanism stemming from Coulomb interactions between different neutral exciton states. Such Coulomb resonances hybridize the exciton wave function over four different electron and hole single-particle orbitals. Comparisons of experimental observations with microscopic eight-band k·p calculations taking into account a realistic quantum dot geometry show good agreement and reveal that the Coulomb resonances arise from broken symmetry in the artificial semiconductor molecule.

[Can we overcome schistosomiasis? A Senegalese example]. / Peut-on vaincre les bilharzioses ? Un exemple sénégalais.

The authors report the results of controlling schistosomiasis in 53 villages from Ninefecha area-(Kedougou District, East Senegal) within Schistosomiasis National Control Program partnership. The four aims were: i) praziquantel treatment of 3324 children 6-14 years old, ii) installation of a laboratory for children prevalence annual monitoring (random draw one in three), iii) health education of the concerned people ("sensitization"), iiii) construction of latrines. 900 latrines are required and 649 have been built. The initial prevalence (2006) of 44% for S. mansoni and 4% for S. haematobium are now respectively 1.9% and 1.4% (2013). The program must be continuous as shown in the Assoni village: a prevalence study in children 0-5 years old, for which praziquantel is not recommended, reveals an infestation rate for S. mansoni of 78% in 2008 and of 47% in 2012. This age group is an important parasite reservoir and health education of parents is absolutely necessary. A permanent and effective center like Ninefescha hospital for distribution of praziquantel, sensitization meetings and latrines control is essential for the success of the program.

[Can schistosomiasis be defeated? An example from Senegal]. / Peut-on vaincre les bilharzioses ? Un exemple sénégalais.

The authors report the results of actions combatting schistosomiasis since 2008 in 53 villages in eastern Senegal, including the creation of 450 latrines and the distribution of praziquentel. The prevalence of Schistosoma mansoni has fallen from 44% in 2006 to 1.8% today. To succeed in eradicating schistosomiasis, access to non-infected water must be improved to ensure the adhesion of local village communities.

Coplanar stripline antenna design for optically detected magnetic resonance on semiconductor quantum dots.

We report on the development and testing of a coplanar stripline antenna that is designed for integration in a magneto-photoluminescence experiment to allow coherent control of individual electron spins confined in single self-assembled semiconductor quantum dots. We discuss the design criteria for such a structure which is multi-functional in the sense that it serves not only as microwave delivery but also as electrical top gate and shadow mask for the single quantum dot spectroscopy. We present test measurements on hydrogenated amorphous silicon, demonstrating electrically detected magnetic resonance using the in-plane component of the oscillating magnetic field created by the coplanar stripline antenna necessary due to the particular geometry of the quantum dot spectroscopy. From reference measurements using a commercial electron spin resonance setup in combination with finite element calculations simulating the field distribution in the structure, we obtain a magnetic field of 0.12 mT at the position where the quantum dots would be integrated into the device. The corresponding π-pulse time of ≈0.5 µs meets the requirements set by the high sensitivity optical spin read-out scheme developed for the quantum dot.

Virus de l'hepatite C et hepatopathies chroniques a Dakar : etude cas-temoins

En Afrique noire; la place de l'infection par le virus de l'hepatite C (VHC) dans la survenue des hepatopathies chroniques reste discutee; en particulier au Senegal ou la prevalence du VHC est moderee. C'est pourquoi une etude cas-temoins a ete menee a l'Hopital Principal de Dakar; en 1995; incluant 73 malades et 73 temoins. Les malades etaient repartis en 2 hepatites chroniques; 25 cirrhoses et 46 carcinomes hepatocellulaires. Les malades et les temoins ont fait l'objet d'etude serologique vis-a-vis du VHC (test ELISA de depistage; test ELISA de 3e generation en cas de positivite; puis confirmation par immunoblot) avec determination du serotype du VHC par methode immunoenzymatique; une recherche d'infection par le virus de l'hepatite B et une recherche d'anticorps anti-delta ont complete l'etude. Seulement 2 malades etaient porteurs d'anticorps anti-VHC (3 p. 100) et la serologie etait douteuse chez 2 autres ; le serotype 2 a ete mis en evidence chez l'un de ces malades ; aucun temoin n'etait positif vis-a-vis du VHC. Cinquante-quatre malades (74 p. 100) et 15 temoins (21 p. 100) etaient porteurs de l'antigene HBs parmi lesquels 13 malades (24 p. 100) et 1 temoin (7 p. 100) etaient porteurs d'anticorps anti-delta. Cette etude montre le role actuellement negligeable du VHC dans la survenue des hepatopathies chroniques en milieu hospitalier au Senegal et confirme le role predominant du virus de l'hepatite B et aggravant du virus de l'hepatite delta. Ces resultats sont confrontes aux donnees de la litterature concernant les pays d'Afrique noire. Au Senegal; l'impact du VHC parait inferieur a celui qui est oberve en Afrique centrale

Prise en charge du diabete de type 2 en Afrique subsaharienne: constats actuels et perspectives

La prise en charge du diabete de type 2 enAfrique subsaharienne presente des particularites qui doivent etre analysees en plusieurs etapes. Au niveau du continent africain : les grands axes de lutte contre le diabete en Afrique comporteront necessairement la mise en place de vastes plans d'information et d'education des professionnels de sante et de la population en general; ainsi que la creation d'infrastructures suffisantes en assurant une disponibilite optimale des traitements .Au niveau des soignants : les principes de prise en charge globale sont les memes que partout ailleurs dans le monde. Ils doivent etre adaptes au contexte socioculturel du patient. Les objectifs doivent etre simples mais repondre aux exigences scientifiques. Au niveau du patient : la realite de la maladie telle qu'elle est percue par le malade africain est bien differente de ce que qui est enseigne dans les facultes occidentales. Les differentes composantes ethnoculturelles de la maladie doivent etre reconnues pour optimiser la prise en charge globale du patient

[Portal hypertension and schistosomiasis: "an originally killing entity"]. / L'hypertension portale des schistosomoses: "une entité originale meurtrière".

In some regions of Africa, Middle-east and Asia, portal hypertension is caused most frequently by bilharziasis far more than by post-hepatic or alcoholic cirrhosis. All schistosomiasis induce hepatic affection, consequence of the eggs embolization in the vessels endings of the portal system, but only Schistosoma mansoni and Asian bilharziasis mainly the Schistosoma japonicum are the cause of severe sequelar fibrosis responsible for a particular portal hypertension. This portal hypertension is original anatomopathologically and physiopathologically. The perivascular concentric fibrosis localised in the portal space is an anatomopathological sequela of bilharzious granulomas outlining embolized eggs. This "stem pipe" aspect constitutes a presinusoidal block inducing a severe portal hypertension without hepatic lobule affection. The recent medical advances regarding this pathology lie in the understanding of the responsible immune mechanisms, the diagnosis and follow-up thanks to ecographic codification of lesions, the complications treatment through varix endoscopic ligature or portal vein derivation. Treatment by praziquantel remains justified together with health education, improving living standard and hopes placed in the future vaccination campaigns associated with medical treatment in endemic areas.

[Decompensated post-schistosomiasis portal hypertension in Richard-Toll, Senegal: first case treated by splenorenal anastomosis in Dakar]. / Hypertension portale post-bilharzienne décompensée à Richard-Toll au Sénégal: premier cas traité à Dakar par anastomose splénorénale.

UNLABELLED: Since the Diama dam on the Senegal river became operative in 1986, an exceptional outbreak of intestinal schistosomiasis occurred in northern Senegal. This is the first case report from this region of a splenorenal derivation performed in Dakar to cure decompensated portal hypertension due to Schistosoma mansoni. CASE REPORT: In June 1998, a 16-year old boy, native from Richard-Toll in the Senegal River Basin, was admitted to the paediatric department of Hôpital Principal, Dakar, Senegal, with a 3 years of recurrent hematemesis. Blood transfusions were required despite propranolol and multiple oesophageal varices sclerotherapies. On admission he weighed 33 kg and was noted to have pallor and moderate hepatosplenomegaly. Lab work included normal liver function tests, a Hgb of 58 mg/L, negative HBs antigen, and high titers of schistosomiasis antibodies (> 1/2000 by the hemagglutination method). Ultrasound revealed an homogeneously enlarged liver, periportal fibrosis and spleen with a grade 2 portal hypertension (WHO score). Endoscopy showed stage 3 oesophageal varices with red spots but no active haemorrhage. After transfusions, a Warren distal splenorenal anastomosis was performed. During the operation, a liver biopsy was obtained, showing periportal fibrosis and schistosomiasis granulomas. The patient was discharged without complication. After 4 years he remains free of any recurrence of his upper gastrointestinal haemorrhage and haemoglobin rate is normal. COMMENTS: Before the inauguration of the dam in 1986, S. mansoni infection was never reported from the Senegal River Basin. But as early as 1988, the first cases of intestinal schistosomiasis began to show up. A few years later, this focus had dramatically extended and in 1991 the first cases of hepatic fibrosis were detected in ultrasonography surveys. The present case involves the first patient from northern Senegal who required surgery for haemorrhagic complications of schistosomiasis induced by liver disease. Considering the high prevalence in this area, and the difficulties of medical management, the need for porto-systemic derivations is likely to rise. These operations are difficult and require specially trained surgeons. They have been largely unavailable in Senegal until now. This case report, involving a child only 10 years after the beginning of the epidemic, underlines the acute need for improving both prevention and medical treatment in order to avoid progression to clinical stages of hepatic schistosomiasis where surgery is unavoidable. In addition, the training of local surgical teams able to deal with these complications is urgently needed in Senegal.

[Disseminated and central nervous system Histoplasma capsulatum infection mimicking neoplasm: difficulties in diagnosis, failure in management]. / Miliaire cérébrale pseudonéoplasique révélatrice d'une histoplasmose disséminée à Histoplasma capsulatum: difficultés diagnostiques, échec thérapeutique.

INTRODUCTION: Infection with Histoplasma capsulatum (Hc) is a rare importing disease in metropolitan France, the most often minor but sometimes letal in its spread form. EXEGESIS: A 58 years old French man, HIV seronegative, was admitted for an alteration of its general condition, disorder and buccal ulcerations. He had a prostate cancer history and came back in France after 17 years in Central Africa. The imaging showed numerous cerebral nodes, a bilateral adrenal tumor, and pulmonary calcifications. Histoplasmosis diagnosis has been done after neurosurgical cerebral biopsy which displayed characteristic Hc. The sick man died 4 months later with multivisceral failures, in spite of amphotericine B treatment followed by oral then intraveinous itraconazole. CONCLUSION: Even in an old tropical residence, ones can be able to conjure up a deep exotic fungal infection, and most specifically Hc histoplasmosis, in front of meaningful multivisceral lesions. Disseminated histoplasmosis (HD) with neurological location is misleading, mimicking tuberculosis or cancer. In order to obtain formal mycological evidence, ones have to make adapted biopsies. Antifungal agents must take into account medicinal interaction. Therefore, prognosis is bad, according to inoculum, immunodeficiency, age of disease and diagnosis delay.

A new primaquine analogue, tafenoquine (WR 238605), for prophylaxis against Plasmodium falciparum malaria.

We tested tafenoquine (WR 238605), a new long-acting 8-aminoquinoline, for its ability to prevent malaria in an area that is holoendemic for Plasmodium falciparum. In a double-blinded, placebo-controlled, randomized clinical trial in western Kenya, adult volunteers received a treatment course of 250 mg halofantrine per day for 3 days, to effect clearance of preexisting parasites. The volunteers were then assigned to 1 of 4 drug regimens: placebo throughout; 3 days of 400 mg (base) of tafenoquine per day, followed by placebo weekly; 3 days of 200 mg of tafenoquine per day, followed by 200 mg per week; and 3 days of 400 mg of tafenoquine per day, followed by 400 mg per week. Prophylaxis was continued for up to 13 weeks. Of the evaluable subjects (223 of 249 randomized subjects), volunteers who received 400 mg tafenoquine for only 3 days had a protective efficacy of 68% (95% confidence interval [CI], 53%-79%), as compared with placebo recipients; those who received 200 mg per day for 3 days followed by 200 mg per week had a protective efficacy of 86% (95% CI, 73%-93%); and those who received 400 mg for 3 days followed by 400 mg per week had a protective efficacy of 89% (95% CI, 77%-95%). A similar number of volunteers in the 4 treatment groups reported adverse events. Prophylactic regimens of 200 mg or 400 mg of tafenoquine, taken weekly for < or =13 weeks, are highly efficacious in preventing falciparum malaria and are well tolerated.

[Plasmodium vivax: therapy update]. / Plasmodium vivax: actualités thérapeutiques.

IMPACT OF PLASMODIUM VIVAX WORLDWIDE: Plasmodium vivax is the most widespread malanal agent in the world. Unlike Plasmodium falciparum, P. vivax can cause early or late recurrence and is not fatal (benign tertian malaria). EMERGENCE OF RESISTANT STRAINS: P. vivax strains resistant to chloroquine, then primaquine, have emerged over the last decade, creating the need for a new therapeutic strategy. TREATMENT OF PRIMARY DISEASE: Generally, chloroquine is the first intention treatment, excepting patients who also have P. falciparum infection or a strain with suspected resistance to chloroquine. Mefloquine, quinine and halofantrine are also logical alternatives. TREATMENT OF RECURRENT DISEASE: A schizonticidal agent should be given followed by a hypnozoitocidal agent, primaquine. Primaquine dosage should now be raised or adjusted to the patient's weight. THERAPEUTIC PERSPECTIVES: Tafenoquine, delayed-release amino-8-quinoleine, is a potential alternative for primaquine for the treatment of recurrences. Studies are also in progress to evaluate the role of primaquine as a prophylaxic agent.