Persistence of viable but non-culturable bacteria during the production and distribution of drinking water

The direct measurement of in situ respiring bacteria using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) shows that, especially for Gram-negative bacteria, large numbers of viable but non-culturable (VBNC) bacteria are present in finished water from a conventional water treatment plant, and the regrowth of bacteria along distribution networks can be seen rapidly by using this very sensitive technique. The level of bacterial inactivation with chlorine is much less important than has been previously supposed (based on experiments with non-injured laboratory strains of bacteria and classical culture techniques). Threshold values of VBNC bacteria leaving water treatment plants or regrowing along distribution systems have to be determined for better control of coliform regrowth and health- risks associated with the consumption of drinking water

Lattice model of oligonucleotide hybridization in solution. II. Specificity and cooperativity

Because oligonucleotides are short sequences of nucleic acid bases, their association in solution with complementary strands (hybridization) is often seen to conform to a simple two-state model. However, experimental evidence suggests that, despite their short length, oligonucleotides may hybridize through multiple states involving intermediates. We investigate whether these apparently contradictory scenarios are possible by imposing different levels of sequence specificity on a lattice model of oligonucleotides in solution, which we introduced in Part I [J. C. Araque et al., J. Chem. Phys. 134, 165103 (2011)]. We find that both multiple-intermediate (weakly cooperative) and two-state (strongly cooperative) transitions are possible and that these are directly linked to the level of sequence specificity. Sequences with low specificity hybridize (base-by-base) by way of multiple stable intermediates with increasing number of paired bases. Such intermediate states are weakly cooperative because the energetic gain from adding an additional base pair is outweighed by the conformational entropy loss. Instead, sequences with high specificity hybridize through multiple metastable intermediates which easily bridge the configurational and energetic gaps between single- and double-stranded states. These metastable intermediates interconvert with minimal loss of conformational entropy leading to a strongly cooperative hybridization. The possibility of both scenarios, multiple- and two-states, is therefore encoded in the specificity of the sequence which in turn defines the level of cooperativity

Impact of bedside open lung biopsies on the management of mechanically ventilated immunocompromised patients with acute respiratory distress syndrome of unknown etiology.

BACKGROUND: Open lung biopsy (OLB) is helpful in the management of patients with acute respiratory distress syndrome (ARDS) of unknown etiology. We determine the impact of surgical lung biopsies performed at the bedside on the management of patients with ARDS. METHODS: We reviewed all consecutive cases of patients with ARDS who underwent a surgical OLB at the bedside in a medical intensive care unit between 1993 and 2005. RESULTS: Biopsies were performed in 19 patients mechanically ventilated for ARDS of unknown etiology despite extensive diagnostic process and empirical therapeutic trials. Among them, 17 (89%) were immunocompromised and 10 patients experienced hematological malignancies. Surgical biopsies were obtained after a median (25%-75%) mechanical ventilation of 5 (2-11) days; mean (+/-SD) Pao(2)/Fio(2) ratio was 119.3 (+/-34.2) mm Hg. Histologic diagnoses were obtained in all cases and were specific in 13 patients (68%), including 9 (47%) not previously suspected. Immediate complications (26%) were local (pneumothorax, minimal bleeding) without general or respiratory consequences. The biopsy resulted in major changes in management in 17 patients (89%). It contributed to a decision to limit care in 12 of 17 patients who died. CONCLUSION: Our data confirm that surgical OLB may have an important impact on the management of patients with ARDS of unknown etiology after extensive diagnostic process. The procedure can be performed at the bedside, is safe, and has a high diagnostic yield leading to major changes in management, including withdrawal of vital support, in the majority of patients

Comparison of decision making and administrative organization for municipal water supplies in medium-sized and small Illinois municipalities

The study was designed to provide information on the decision making and organizational characteristics of municipally owned water systems in small and medium-sized Illinois municipalities, and to relate these characteristics to municipal as well as other water system characteristics. Data on the municipal water systems of 228 Illinois incorporated municipalities were gathered through mail and telephone surveys, as well as from secondary sources. The municipalities were chosen as part of a 50-percent sample, stratified by size, of all incorporated municipalities in Illinois with populations between 1,000 and 50,000. In addition to selected descriptive information on the water systems, the data are reported under water system decision making; planning and financial management; and technical management. Attempts to determine the relationships between the dependent variables and municipal and water system characteristics indicated a general weakness or absence of such relationships. While the quality of the data cannot be ruled out with certainty as the reason for the absence of the relationships, it is suggested that the relative lack of active interest on the part of municipalities in their water systems may account for the findings. The historical absence of the necessity to actively manage the water system other than in a routine fashion may have left these water systems quite unprepared to meet future sudden challenges.U.S. Department of the InteriorU.S. Geological SurveyOpe

Nocturnal activities of phlebotomine sand flies (Diptera: Psychodidae) in Baringo County, Kenya

Leishmaniasis is a disease of both humans and animals. It is transmitted by the bite of sand flies of the genus Phlebotomus in the Old World and Lutzomyia in the New World. Nocturnal activities of phlebotomine sand flies were monitored by trapping flies exiting and entering termite mounds and animal burrows in Baringo County. Exit/entrance traps were set from dusk to midnight and from midnight to dawn in the termite mound and animal burrow openings. The study which lasted seven months (November 1993/May 1994), was designed to reveal sand fly behavior in their natural habitats. A total of 11,787 sand flies was trapped and their nocturnal activities studied. Significantly more sand flies(85.6%) were caught exiting than entering animal burrows and termite mounds in the 1st half of the night p<0.05. This trend was reversed by sand flies (61.4%) caught entering the burrows termite mounds during the 2nd half of the night p<0.05. Most sugar/positive sand flies were collected after midnight in both animal burrows and termite mounds while more blood/fed sand flies were caught in the 1st than in the 2nd half of the night p<0.05. At Perkerra, 87.8% of the blood/fed female sand flies were trapped in the 1st half of the night compared with 12.2% caught in the 2nd half. At Rabai, 72.6% of the total number of those caught blood fed were in the 1st half and 27.4% in the 2nd half of the night. P. martini which is the vector of L. donovani which causes visceral leishmaniasis, was predominantly trapped in termite mounds whereas P duboscqi (vector of L. major) that causes cutaneous leishmaniasis, was trapped in large numbers in animal burrows. These habitats pre/dispose themselves as ideal targets for control measures of the vectors. Keywords: Sugar, blood feeding, sand flies, animal burrows, termite mounds, Keny

Le paludisme urbain à Yaoundé (Cameroun) : 2. Etude entomologique dans deux quartiers peu urbanisés

International audienceA one year entomological survey was carried out to precise the malaria vectors and the malaria transmission in Yaounde, the Cameroon capital (800,000 inhabitants). The study was done in two districts not yet fully urbanized: Nkol Bikok and Nkol Bisson. The latter is located at the periphery and has a pool. Anopheles gambiae was the only human malaria vector. Its agressivity for man depended on the urbanization of the district. Annual man biting rate was 284 in Nkol Bikok and 1,813 in Nkol Bisson. The densities were maximum in May-June and in October-November, corresponding to the end of the short and long rainy seasons. The presence of A. gambiae was permanent except in August-September in Nkol Bikok. In Nkol Bisson the density was higher in the houses near the pool. The yearly inoculation rate (h) was 14 in Nkol Bikok and 30 in Nkol Bisson. The vectorial transmission was observed in may in Nkol Bikok and during four months (June, August, January, February) in Nkol Bisson. These entomological data showed clearly that malaria transmission actually occurred in Yaounde and that the probability to receive at least one infected anopheline bite per year was very near to 1 for inhabitants unprotected against mosquito bites.Une étude longitudinale basée sur la capture des moustiques sur sujets humains s'est déroulée pendant un an dans deux quartiers de la ville de Yaoundé, l'un est situé à la périphérie de la ville (Nkol Bisson) et l'autre est plus central (Nkol Bikok). Ces deux quartiers présentent encore un caractère périurbain mais ils sont en pleine urbanisation. Le vecteur du paludisme humain identifé est Anopheles gambiae. Sa densité agressive pour l'homme (ma) est variable selon le degré d'urbanisation des quartiers : forte en Zone périphérique (ma annuel = I 813) et faible en zone centrale (ma annuel = 284). Cette densité est importante de mai à juin et d'octobre 6 novembre, c'est-à-dire à la fin de la petite et de la grande saison des pluies. Le taux d'inoculation (h) varie comme les densités agressives : h annuel = 30 en zone périphérique contre 14 en zone centrale. La transmission vectorielle est notable seulement pendant un mois (mai) à Nkol Bikok et pendant quatre mois (juin, août, janvier, février) à Nkol Bisson. Le risque quotidien d'au moins une inoculation par A. gambiae est environ deux fois plus élevé en zone périphérique qu'en zone centrale

¿qué es la crítica poscolonial?

En este texto Robert Young se ocupa de analizar brevemente la historia y el concepto de crítica postcolonial. El autor sostiene que la teoría postcolonial ha combinado la herencia teórica del pensamiento postestructuralista con perspectivas de escritores no occidentales. En el texto se analiza el trabajo de autores como Said, Bhabha y Spivak, que son considerados los ejes de la teoría postcolonial

¿qué es la crítica poscolonial?

En este texto Robert Young se ocupa de analizar brevemente la historia y el concepto de crítica postcolonial. El autor sostiene que la teoría postcolonial ha combinado la herencia teórica del pensamiento postestructuralista con perspectivas de escritores no occidentales. En el texto se analiza el trabajo de autores como Said, Bhabha y Spivak, que son considerados los ejes de la teoría postcolonial