NaOCl and EDTA irrigating solutions for endodontics: SEM findings

Premolars roots of humans were manually instrumented with K-type files and irrigated with different solutions to evaluate the rate of cleaning of endodontic surface. Root canals irrigated with 0.9% saline solution or H2O2 (10 volumes) showed the presence of predentin and amorphous smear layer. Thick smear layer was always present on endodontic walls rinsed with 5% solution of NaOCl. Specimens treated with 0.2% solution of EDTA showed partially clean dentinal tubules orifices and remnants of a thin smear layer. Occasional uninstrumented areas of the same roots presented smear layer remnants and predentin with calcified bacteriae. The root canals irrigated with NaOCl and EDTA solutions alternated after each instrument showed at the dentin surface thick smear layer: only few dentinal tubules orifices were visible.Endodontic surface of root canals irrigated with NaOCl during instrumentation and finally rinsed with EDTA solutions showed the most homogeneous ultrastructural pictures: partially clean dentinal orifices were detectable in the whole canals.Les canaux de la racine dentaire des prémolaires humaines ont été instrumentés manuellement avec files K type et ensuite irrigués avec différentes solutions pour évaluer les conditions de netteté de la surface endodontique.Les canaux irrigués avec une solution saline à 0,9% ou de H2O2 (10 volumes) ont démontré la présence de prédentine ou d’une couche de tissu salie. Cette couche était toujours présente sur la paroi endodontique lavée avec une solution de NaOCl à 5%. Les exemplaires traités avec une solution de EDTA à 0,2% ont démontré une netteté partielle des orifices tubulaires dentinaires et seulement un mince résidu non propre. Les zones non instrumentées de la même racine présentaient au contraire des résidus et une prédentine avec nombreuses bactéries calcifiées. Les canaux irrigués avec une solution de NaOCl et EDTA alternée ont démontré la présence d’une épaisse couche non propre et la visualisation de quelques orifices tubulaires. La surface endodontique des canaux de la racine irriguée avec NaOCl pendant l’instrumentation et ensuite lavée avec EDTA a démontré les images ultrastructurales les plus homogènes: les orifices dentinaires partiellement nettoyés pouvait être visualisés sur toute la surface du canal

Monitoring of lung edema by microwave reflectometry during lung ischemia-reperfusion injury in vivo

It is still unclear whether lung edema can be monitored by microwave reflectometry and whether the measured changes in lung dry matter content (DMC) are accompanied by changes in PaO(2) and in pro-to anti-inflammatory cytokine expression (IFN-gamma and IL-10). Right rat lung hili were cross-clamped at 37 degrees C for 0, 60, 90 or 120 min ischemia followed by 120 min reperfusion. After 90 min (DMC: 15.9 +/- 1.4%; PaO(2): 76.7 +/- 18 mm Hg) and 120 min ischemia (DMC: 12.8 +/- 0.6%; PaO(2): 43 +/- 7 mm Hg), a significant decrease in DMC and PaO(2) throughout reperfusion compared to 0 min ischemia (DMC: 19.5 +/- 1.11%; PaO(2): 247 +/- 33 mm Hg; p < 0.05) was observed. DMC and PaO(2) decreased after 60 min ischemia but recovered during reperfusion (DMC: 18.5 +/- 2.4%; PaO(2) : 173 +/- 30 mm Hg). DMC values reflected changes on the physiological and molecular level. In conclusion, lung edema monitoring by microwave reflectometry might become a tool for the thoracic surgeon. Copyright (c) 2006 S. Karger AG, Basel

Coordination Implications of Software Coupling in Open Source Projects

The effect of software coupling on the quality of software has been studied quite widely since the seminal paper on software modularity by Parnas [1]. However, the effect of the increase in software coupling on the coordination of the developers has not been researched as much. In commercial software development environments there normally are coordination mechanisms in place to manage the coordination requirements due to software dependencies. But, in the case of Open Source software such coordination mechanisms are harder to implement, as the developers tend to rely solely on electronic means of communication. Hence, an understanding of the changing coordination requirements is essential to the management of an Open Source project. In this paper we study the effect of changes in software coupling on the coordination requirements in a case study of a popular Open Source project called JBoss

Observational reinforcement learning in children and young adults

Observational learning is essential for the acquisition of new behavior in educational practices and daily life and serves as an important mechanism for human cognitive and social-emotional development. However, we know little about its underlying neurocomputational mechanisms from a developmental perspective. In this study we used model-based fMRI to investigate differences in observational learning and individual learning between children and younger adults. Prediction errors (PE), the difference between experienced and predicted outcomes, related positively to striatal and ventral medial prefrontal cortex activation during individual learning and showed no age-related differences. PE-related activation during observational learning was more pronounced when outcomes were worse than predicted. Particularly, negative PE-coding in the dorsal medial prefrontal cortex was stronger in adults compared to children and was associated with improved observational learning in children and adults. The current findings pave the way to better understand observational learning challenges across development and educational settings

The Complete Genome Sequence of Yersinia pseudotuberculosis IP31758, the Causative Agent of Far East Scarlet-Like Fever

The first reported Far East scarlet-like fever (FESLF) epidemic swept the Pacific coastal region of Russia in the late 1950s. Symptoms of the severe infection included erythematous skin rash and desquamation, exanthema, hyperhemic tongue, and a toxic shock syndrome. The term FESLF was coined for the infection because it shares clinical presentations with scarlet fever caused by group A streptococci. The causative agent was later identified as Yersinia pseudotuberculosis, although the range of morbidities was vastly different from classical pseudotuberculosis symptoms. To understand the origin and emergence of the peculiar clinical features of FESLF, we have sequenced the genome of the FESLF-causing strain Y. pseudotuberculosis IP31758 and compared it with that of another Y. pseudotuberculosis strain, IP32953, which causes classical gastrointestinal symptoms. The unique gene pool of Y pseudotuberculosis IP31758 accounts for more than 260 strain-specific genes and introduces individual physiological capabilities and virulence determinants, with a significant proportion horizontally acquired that likely originated from Enterobacteriaceae and other soil-dwelling bacteria that persist in the same ecological niche. The mobile genome pool includes two novel plasmids phylogenetically unrelated to all currently reported Yersinia plasmids. An icm/dot type IVB secretion system, shared only with the intracellular persisting pathogens of the order Legionellales, was found on the larger plasmid and could contribute to scarlatinoid fever symptoms in patients due to the introduction of immunomodulatory and immunosuppressive capabilities. We determined the common and unique traits resulting from genome evolution and speciation within the genus Yersinia and drew a more accurate species border between Y. pseudotuberculosis and Y. pestis. In contrast to the lack of genetic diversity observed in the evolutionary young descending Y. pestis lineage, the population genetics of Y. pseudotuberculosis is more heterogenous. Both Y. pseudotuberculosis strains IP31758 and the previously sequenced Y. pseudotuberculosis strain IP32953 have evolved by the acquisition of specific plasmids and by the horizontal acquisition and incorporation of different genetic information into the chromosome, which all together or independently seems to potentially impact the phenotypic adaptation of these two strains

Pathogenomes and virulence profiles of representative big six non-O157 serogroup Shiga toxin-producing Escherichia coli

Shiga toxin (Stx)-producing Escherichia coli (STEC) of non-O157:H7 serotypes are responsible for global and widespread human food-borne disease. Among these serogroups, O26, O45, O103, O111, O121, and O145 account for the majority of clinical infections and are colloquially referred to as the “Big Six.” The “Big Six” strain panel we sequenced and analyzed in this study are reference type cultures comprised of six strains representing each of the non-O157 STEC serogroups curated and distributed by the American Type Culture Collection (ATCC) as a resource to the research community under panel number ATCC MP-9. The application of long- and short-read hybrid sequencing yielded closed chromosomes and a total of 14 plasmids of diverse functions. Through high-resolution comparative phylogenomics, we cataloged the shared and strain-specific virulence and resistance gene content and established the close relationship of serogroup O26 and O103 strains featuring flagellar H-type 11. Virulence phenotyping revealed statistically significant differences in the Stx-production capabilities that we found to be correlated to the strain’s individual stx-status. Among the carried Stx1a, Stx2a, and Stx2d phages, the Stx2a phage is by far the most responsive upon RecA-mediated phage mobilization, and in consequence, stx2a + isolates produced the highest-level of toxin in this panel. The availability of high-quality closed genomes for this “Big Six” reference set, including carried plasmids, along with the recorded genomic virulence profiles and Stx-production phenotypes will provide a valuable foundation to further explore the plasticity in evolutionary trajectories in these emerging non-O157 STEC lineages, which are major culprits of human food-borne disease

Who Ate Whom? Adaptive Helicobacter Genomic Changes That Accompanied a Host Jump from Early Humans to Large Felines

Helicobacter pylori infection of humans is so old that its population genetic structure reflects that of ancient human migrations. A closely related species, Helicobacter acinonychis, is specific for large felines, including cheetahs, lions, and tigers, whereas hosts more closely related to humans harbor more distantly related Helicobacter species. This observation suggests a jump between host species. But who ate whom and when did it happen? In order to resolve this question, we determined the genomic sequence of H. acinonychis strain Sheeba and compared it to genomes from H. pylori. The conserved core genes between the genomes are so similar that the host jump probably occurred within the last 200,000 (range 50,000–400,000) years. However, the Sheeba genome also possesses unique features that indicate the direction of the host jump, namely from early humans to cats. Sheeba possesses an unusually large number of highly fragmented genes, many encoding outer membrane proteins, which may have been destroyed in order to bypass deleterious responses from the feline host immune system. In addition, the few Sheeba-specific genes that were found include a cluster of genes encoding sialylation of the bacterial cell surface carbohydrates, which were imported by horizontal genetic exchange and might also help to evade host immune defenses. These results provide a genomic basis for elucidating molecular events that allow bacteria to adapt to novel animal hosts