Limiting Factors in Treatment Success of Biofilm-Forming Streptococci in the Case of Canine Infective Endocarditis Caused by Streptococcus canis

An 8-year-old male Rhodesian Ridgeback was presented with fever and severe thrombocytopenia. Clinical and laboratory examination, echocardiography, blood culture, and pathohistology revealed evidence of infective endocarditis, ischemic renal infarcts, and septic encephalitis. Treatment was started immediately but the dog’s condition worsened, and the dog had to be euthanized. The causative Streptococcus canis strain was detected by blood culture and MALDI-TOF MS and analyzed using whole-genome sequencing and multilocus sequence typing. Antibiotic susceptibility testing did not detect any resistance. The affected heart valve was analyzed using FISH imaging, which showed a streptococcal biofilm on the heart valve. Bacteria in biofilms are recalcitrant to antibiotic treatment. Early diagnosis could be beneficial to treatment outcome. Treatment of endocarditis could be improved by researching the optimal dosage of antibiotics in conjunction with the use of biofilm-active drugs

Green Edge ice camp campaigns : understanding the processes controlling the under-ice Arctic phytoplankton spring bloom

The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797∘ N, 63.7895∘ W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea-ice cover from the surface to the bottom (at 360 m depth) to better understand the factors driving the PSB. Key variables, such as conservative temperature, absolute salinity, radiance, irradiance, nutrient concentrations, chlorophyll a concentration, bacteria, phytoplankton and zooplankton abundance and taxonomy, and carbon stocks and fluxes were routinely measured at the ice camp. Meteorological and snow-relevant variables were also monitored. Here, we present the results of a joint effort to tidy and standardize the collected datasets, which will facilitate their reuse in other Arctic studies

Étude des propriétés spectroscopiques et photochimiques du ligand dibenzylidèneacétone (DBA) en relation avec la photochimie des complexes de type M₂(DBA)₃ ou M=Pd ou Pt

Dans la première partie du travail, il sera démontré, via un ensemble de techniques, telles les spectroscopies électronique et vibrationnelle, la photolyse éclair picoseconde ainsi que la désactivation de fluorescence, que la bande d'absorption de plus basse énergie (322nm) du ligand dibenzylidènecétone (DBA) correspond bien à un état de transfert de charge; la réaction de phototransfert se faisant du groupement aromatique au groupement cétonique. La photoisomérisation cis-trans de ce même ligand sera mise en évidence par spectroscopie électronique et résonance magnétique nucléaire. Dans la deuxième partie, la photochimie des complexes de type M₂(DBA)₃ (où M = Pd ou Pt et DBA = dibenzylidènecétone) sera abordée. La photolyse éclair démontrera que le ligand participe au processus photochimique. A partir des connaissances acquises sur le comportement photochimique du ligand libre, deux hypothèses seront émises quant à la nature du processus impliqué dans les complexes: soit le transfert de charge intramoléculaire ou l'interconversion cis-trans

Étude des propriétés spectroscopiques et photochimiques du ligand dibenzylidèneacétone (DBA) en relation avec la photochimie des complexes de type M?(DBA)? ou M=Pd ou Pt

Dans la première partie du travail, il sera démontré, via un ensemble de techniques, telles les spectroscopies électronique et vibrationnelle, la photolyse éclair picoseconde ainsi que la désactivation de fluorescence, que la bande d'absorption de plus basse énergie (322nm) du ligand dibenzylidènecétone (DBA) correspond bien à un état de transfert de charge; la réaction de phototransfert se faisant du groupement aromatique au groupement cétonique. La photoisomérisation cis-trans de ce même ligand sera mise en évidence par spectroscopie électronique et résonance magnétique nucléaire. Dans la deuxième partie, la photochimie des complexes de type M?(DBA)? (où M = Pd ou Pt et DBA = dibenzylidènecétone) sera abordée. La photolyse éclair démontrera que le ligand participe au processus photochimique. A partir des connaissances acquises sur le comportement photochimique du ligand libre, deux hypothèses seront émises quant à la nature du processus impliqué dans les complexes: soit le transfert de charge intramoléculaire ou l'interconversion cis-trans

Group Additivity Values for Estimating the Enthalpy of Formation of Organic Compounds: An Update and Reappraisal. 2. C, H, N, O, S, and Halogens

This study extends a previous publication on group additivity values (GAVs) for the elements C, H, and O, to include the elements nitrogen, sulfur, and the halogens. The present state and utility of the Benson additivity schemes for estimating the enthalpy of formation (Δ_f<i>H</i>⁰) of organic compounds are again described, extending them to include more elements. Old and new GAVs for a wide variety of compounds are provided and are revised where necessary. When new terms are proposed, or old ones are significantly altered, the rationale for so doing is presented. GAV derived ring strain values for benzene and pyridine indicate that the aromatic stabilization of each is essentially the same. As before, the thermochemical consequences of replacing one functional group by another are also shown, thus permitting quick shortcuts to the estimation of new Δ_f<i>H</i>⁰ values