Inherent-opening-controlled pattern formation in carbon nanotube arrays

We have introduced inherent openings into densely packed carbon nanotube arrays to study self-organized pattern formation when the arrays undergo a wetting–dewetting treatment from nanotube tips. These inherent openings, made of circular or elongated hollows in nanotube mats, serve as dewetting centres, from where liquid recedes from. As the dewetting centres initiate dry zones and the dry zones expand, surrounding nanotubes are pulled away from the dewetting centres by liquid surface tension. Among short nanotubes, the self-organized patterns are consistent with the shape of the inherent openings, i.e. slender openings lead to elongated trench-like structures, and circular holes result in relatively round nest-like arrangements. Nanotubes in a relatively high mat are more connected, like in an elastic body, than those in a short mat. Small cracks often initialize themselves in a relatively high mat, along two or more adjacent round openings; each of the cracks evolves into a trench as liquid dries up. Self-organized pattern control with inherent openings needs to initiate the dewetting process above the nanotube tips. If there is no liquid on top, inherent openings barely enlarge themselves after the wetting–dewetting treatment

An effective long-range attraction between protein molecules in solutions studied by small angle neutron scattering

Small angle neutron scattering intensity distributions taken from cytochrome C and lysozyme protein solutions show a rising intensity at very small wave vector, Q, which can be interpreted in terms of the presence of a weak long-range attraction between protein molecules. This interaction has a range several times that of the diameter of the protein molecule, much greater than the range of the screened electrostatic repulsion. We show evidence that this long-range attraction is closely related to the type of anion present and ion concentration in the solution

The contribution of water contact behavior to the high Schistosoma mansoni Infection rates observed in the Senegal River Basin

Contains fulltext : 97422.pdf (publisher's version ) (Open Access)BACKGROUND: Schistosomiasis is one of the major parasitic diseases in the world in terms of people infected and those at risk. Infection occurs through contact with water contaminated with larval forms of the parasite, which are released by freshwater snails and then penetrate the skin of people. Schistosomiasis infection and human water contact are thus essentially linked, and more knowledge about their relationship will help us to develop appropriate control measures. So far, only few studies have related water contact patterns to infection levels. METHODS: We have conducted detailed direct water contact observations in a village in Northern Senegal during the first years of a massive Schistosoma mansoni outbreak to determine the role of human water contact in the extent of the epidemic.We quantified water contact activities in terms of frequency and duration, and described how these vary with age and sex. Moreover, we assessed the relationship between water contact- and infection intensity patterns to further elucidate the contribution of exposure to the transmission of schistosomiasis. RESULTS: This resulted in over 120,000 recorded water contacts for 1651 subjects over 175 observation days. Bathing was the main activity, followed by household activities. Frequency and duration of water contact depended on age and sex rather than season. Water contacts peaked in adolescents, women spent almost twice as much time in the water as men, and water contacts were more intense in the afternoon than in the morning, with sex-specific intensity peaks. The average number of water contacts per person per day in this population was 0.42; the average time spent in the water per person per day was 4.3 minutes. CONCLUSIONS: The observed patterns of water contact behavior are not unusual and have been described before in various other settings in sub-Saharan Africa. Moreover, water contact levels were not exceptionally high and thus cannot explain the extremely high S. mansoni infection intensities as observed in Northern Senegal. Comparison with fecal egg counts in the respective age and sex groups further revealed that water contact levels did not unambiguously correspond with infection levels, indicating that factors other than exposure also play a role in determining intensity of infection

Avantages des biodigesteurs sur le bois de chauffe dans les élevages laitiers à Kaolack (Sénégal)

Le déficit énergétique constitue une contrainte à l’épanouissement des ménages ruraux notamment, au niveau de l’énergie de cuisson. Les femmes utilisent le bois de chauffe pour les besoins énergétiques de la cuisson mais aussi, pour la pasteurisation du lait. Cette étude met en évidence les avantages de l’utilisation des biodigesteurs sur le bois de chauffe dans les élevages laitiers à Kaolack (Sénégal). Cent seize ménages ont été enquêtés dont 58 détenteurs de biodigesteurs. Les résultats montrent que les ménages possédant un biodigesteur avaient plus de temps pour se consacrer à des activités rémunératrices ou pour le bien être de la famille avec un tiers (32,75 %) qui mettent moins de 2 h par jour pour la recherche du bois et 2 h pour la cuisson d’un repas contre (67,25 %) de ménages sans biodigesteurs qui y consacraient 2 à 6 h par jour et plus de 3 h pour la cuisson d’un repas. Plus du quart (25,86 %) des ménages avec biodigesteurs utilisaient le biogaz comme source d’éclairage. De même, 36,20 % préparent les repas et pasteurisent le lait avec le biogaz. Il est également constaté une réduction de la fréquence des pathologies respiratoires et oculaires mais aussi des dépenses pour l’achat de combustible et de compost.Mots clés: Biogaz ; bois ; élevages laitiers ; économie des ménages ; Kaolack ; Sénégal Biodigester benefits on wood heating in dairy farming of Kaolack (Senegal)The energy deficit is a major constraint to the development of rural house holds including at cooking energy. Women use firewood for cooking energy needs but also for the pasteurization of milk. This study highlights the benefits of using biogas digesters on firewood in dairy farms in Kaolack (Senegal). One Hundred sixteen households were surveyed of which 58 possessed biodigester.The results show that households with a biodigester had much more time devoted to income-generating activities or for the welfare of the family. One third (32.75 %) of biodigester owners take less than 2 hours per day for wood search and 2 hours for cooking a meal against (67.25 %) of house holds without biodigester who spent 2 to 6 hours per day and put more than 3 hours to cook meal. More than a quarter (25.86 %) of households with biodigester used biogas as a lighting. Similarly, 36.20 % Cook food and pasteurize milk with biogas.The used of biogas expenses for the purchase of fuel as well as the compost for filed fertilization. It seem that biogas utilization reduce the incidence of respiratory and eye diseases.Keywords: Biogas ; wood ; dairy farms ; household economy ; Kaolack ; Senegal

A New Fossil Amiid from the Eocene of Senegal and the Persistence of Extinct Marine Amiids after the Cretaceous–Paleogene Boundary

We report a new fossil amiid from Eocene rocks of West Africa representing the first record of this clade from Senegal. The new specimen has a maxilla that is very similar in size to that of Amia calva. It is distinctly smaller than reported remains of another West African Eocene taxon, Maliamia gigas. We tentatively refer the Senegal specimen to Vidalamiini because it has the large postmaxillary process diagnostic of this clade; however, it also exhibits anatomical features not previously described in extinct amiids. We recovered the specimen in rocks of the Lam-Lam Formation in Central-Western Senegal that we interpret to have been a shallow marine depositional environment. The occurrence of an Eocene marine amiid contradicts existing hypotheses that marine amiids were generally absent after the Cretaceous– Paleogene boundary having been replaced by freshwater taxa. Research completed since the initial discovery of Maliamia gigas indicates that this Eocene taxon was also found in shallow marine rocks

Immunization: vital progress, unfinished agenda.

Vaccination against infectious diseases has changed the future of the human species, saving millions of lives every year, both children and adults, and providing major benefits to society as a whole. Here we show, however, that national and sub-national coverage of vaccination varies greatly and major unmet needs persist. Although scientific progress opens exciting perspectives in terms of new vaccines, the pathway from discovery to sustainable implementation can be long and difficult, from the financing, development and licensing to programme implementation and public acceptance. Immunization is one of the best investments in health and should remain a priority for research, industry, public health and society