Scedosporium species show decreased susceptibility to the majority of systemic antifungal drugs. Acquired resistance is likely to disseminate differentially with the mode of exchange of genetic ...material between lineages. Inter- and intraspecific diversities of Scedosporium species were analyzed for three partitions (rDNA internal transcribed spacer gene ITS, partial β-tubulin gene, and amplified fragment length polymorphism profiles), with the aim to establish distribution of resistance between species, populations, and strains. Heterogeneity of and recombination between lineages were determined, and distances between clusters were calculated using a centroid approach. Clinical, geographic, and antifungal data were plotted on diversity networks. Scedosporium minutisporum, Scedosporium desertorum, and Scedosporium aurantiacum were distinguished unambiguously in all partitions and had differential antifungal susceptibility profiles (ASP). Pseudallescheria fusoidea and Pseudallescheria ellipsoidea were indistinguishable from Scedosporium boydii. Pseudallescheria angusta took an intermediate position between Scedosporium apiospermum and S. boydii. Scedosporium boydii and S. apiospermum had identical ASP. Differences in (multi)resistance were linked to individual strains. S. apiospermum and S. boydii showed limited interbreeding and were recognized as valid, sympatric species. The S. apiospermum/S. boydii group, comprising the main clinically relevant Scedosporium species, consists of separate lineages and is interpreted as a complex undergoing sympatric evolution with incomplete lineage sorting. In routine diagnostics, the lineages in S. apiospermum/S. boydii are indicated with the umbrella descriptor "S. apiospermum complex"; individual species can be identified with rDNA ITS with 96.3% confidence. Voriconazole is recommended as the first-line treatment; resistance against this compound is rare.
Snow in the environment acts as a host to rich chemistry and provides a matrix for physical exchange of contaminants within the ecosystem. The goal of this review is to summarise the current state of ...knowledge of physical processes and chemical reactivity in surface snow with relevance to polar regions. It focuses on a description of impurities in distinct compartments present in surface snow, such as snow crystals, grain boundaries, crystal surfaces, and liquid parts. It emphasises the microscopic description of the ice surface and its link with the environment. Distinct differences between the disordered air-ice interface, often termed quasi-liquid layer, and a liquid phase are highlighted. The reactivity in these different compartments of surface snow is discussed using many experimental studies, simulations, and selected snow models from the molecular to the macro-scale. Although new experimental techniques have extended our knowledge of the surface properties of ice and their impact on some single reactions and processes, others occurring on, at or within snow grains remain unquantified. The presence of liquid or liquid-like compartments either due to the formation of brine or disorder at surfaces of snow crystals below the freezing point may strongly modify reaction rates. Therefore, future experiments should include a detailed characterisation of the surface properties of the ice matrices. A further point that remains largely unresolved is the distribution of impurities between the different domains of the condensed phase inside the snowpack, i.e. in the bulk solid, in liquid at the surface or trapped in confined pockets within or between grains, or at the surface. While surface-sensitive laboratory techniques may in the future help to resolve this point for equilibrium conditions, additional uncertainty for the environmental snowpack may be caused by the highly dynamic nature of the snowpack due to the fast metamorphism occurring under certain environmental conditions. Due to these gaps in knowledge the first snow chemistry models have attempted to reproduce certain processes like the long-term incorporation of volatile compounds in snow and firn or the release of reactive species from the snowpack. Although so far none of the models offers a coupled approach of physical and chemical processes or a detailed representation of the different compartments, they have successfully been used to reproduce some field experiments. A fully coupled snow chemistry and physics model remains to be developed.
We used intravascular ultrasound (IVUS) to evaluate recurrence after sirolimus-eluting stent (SES) implantation treatment of in-stent restenosis (ISR).
Forty-eight ISR lesions (41 patients with ...objective evidence of ischemia) were treated with SES. Recurrent ISR was identified in 11 lesions (all focal); repeat revascularization was performed in 10. These were compared with 16 patients (19 lesions) without recurrence as documented by angiography. Nine of 11 recurrent lesions had a minimum stent area (MSA) <5.0 mm2 versus 5 of 19 nonrecurrent lesions (P=0.003); 7 of 11 recurrent lesions had an MSA <4.0 mm2 versus 4 of 19 nonrecurrent lesions (P=0.02); and 4 of 11 recurrent lesions had an MSA <3.0 mm2 versus 1 of 19 nonrecurrent lesions (P=0.03). A gap between SESs was identified in 3 of 11 recurrences versus 1 of 19 nonrecurrent lesions.
Stent underexpansion is a significant cause of failure after SES implantation treatment of ISR.
Mg-based implants, have useful properties such as biocompatibility, low density and elastic modulus close to natural bones eliminating of additional surgery for implant removal. On the other hand, ...they degrade rapidly in the early stage after implantation. This leads to some problems such as fast decreasing mechanical properties in a short time, aggregation of hydrogen bubble and gap formation between the implants and the tissue. This work aims at studying the effect of adding 0.5 wt% of Sn and Bi as alloying elements on the microstructure and in-vitro degradation behavior of as-cast Mg- 4 wt%Zn alloy without and with Ca-P coating. The evaluation process was achieved using optical and scanning electron microscopy, X-ray diffraction, in addition to the corrosion behavior using immersing process in simulated body fluid (SBF). The results showed clearly that the alloy containing Sn represents the lowest degradation rate, but the alloy containing Bi shows the highest degradation rate. In order to improve the degradation rate of the investigated alloys, coating with Ca-P using autocatalytic technique was applied. Coating process led to decrease the degradation rate of as-cast Mg-4wt%Zn and Mg-4wt%Zn-0.5 wt%Bi alloys, but it increased the degradation rate of Mg-4 wt%Zn-0.5 wt%Sn alloy.
•The effect of Sn and Bi addition on microstructure of Mg-4Zn alloy is investigated.•The effect of Sn and Bi addition on bio-degradation rate of Mg-4Zn alloy is investigated.•Low degradation rate of Sn-added alloy as compared with Bi-added alloy is obtained.
We sought to determine the predictors of stent thrombosis after sirolimus-eluting stent (SES) implantation.
A number of cases of stent thrombosis have been reported after commercial release of the ...SES in the “real world,” such that the U.S. Food and Drug Administration issued a warning.
Fifteen patients who developed stent thrombosis after successful SES implantation were analyzed and compared with 45 matched control patients who had no evidence of stent thrombosis.
Minimum stent cross-sectional area (MSA) (4.3 ± 1.6 mm2vs. 6.2 ± 1.9 mm2, p < 0.001) and stent expansion (0.65 ± 0.18 vs. 0.85 ± 0.14, p < 0.001) were significantly smaller in the stent thrombosis group than in the matched control patients. There was no significant difference in the rate of SES malapposition between the groups. However, the presence of a significant residual reference segment stenosis was more common in the stent thrombosis group compared with the matched control group (67% vs. 9%, p < 0.001). Independent predictors of stent thrombosis were stent underexpansion (p = 0.03) and a significant residual reference segment stenosis (p = 0.02).
Stent underexpansion and residual reference segment stenosis are associated with stent thrombosis after successful SES implantation.
Mucormycosis caused, in part, by representatives of the genus Cunninghamella is a severe infection with high mortality in patients with impaired immunity. Several species have been described in the ...literature as etiologic agents. A DNA barcoding study using ITS rDNA and tef-1α provided concordance of molecular data with conventional characters. The currently accepted Cunninghamella species were well supported in phylogenetic trees of both markers except for C. septata with ITS that clustered in the C. echinulata clade. Sequence variability was distinctly higher for the ITS than for tef-1α. Intraspecific ITS variability of some of the species exceeded that between some closely related species, but the marker remained applicable for species identification. The most variable species for both markers was C. echinulata. Cunninghamella bertholletiae is the main pathogenic species; infections by C. blakesleeana, C. echinulata, and C. elegans are highly exceptional.
The wealth of air quality information provided by satellite infrared observations of ammonia (NH3), carbon monoxide (CO), formic acid (HCOOH), and methanol (CH3OH) is currently being explored and ...used for a number of applications, especially at regional or global scales. These applications include air quality monitoring, trend analysis, emissions, and model evaluation. This study provides one of the first direct validations of Tropospheric Emission Spectrometer (TES) satellite-retrieved profiles of NH3, CH3OH, and HCOOH through comparisons with coincident aircraft profiles. The comparisons are performed over the Canadian oil sands region during the intensive field campaign (August–September, 2013) in support of the Joint Canada–Alberta Implementation Plan for Oil Sands Monitoring (JOSM). The satellite/aircraft comparisons over this region during this period produced errors of (i) +0.08 ± 0.25 ppbv for NH3, (ii) +7.5 ± 23 ppbv for CO, (iii) +0.19 ± 0.46 ppbv for HCOOH, and (iv) −1.1 ± 0.39 ppbv for CH3OH. These values mostly agree with previously estimated retrieval errors; however, the relatively large negative bias in CH3OH and the significantly greater positive bias for larger HCOOH and CO values observed during this study warrant further investigation. Satellite and aircraft ammonia observations during the field campaign are also used in an initial effort to perform preliminary evaluations of Environment Canada's Global Environmental Multi-scale – Modelling Air quality and CHemistry (GEM-MACH) air quality modelling system at high resolution (2.5 × 2.5 km2). These initial results indicate a model underprediction of ~ 0.6 ppbv (~ 60 %) for NH3, during the field campaign period. The TES/model CO comparison differences are ~ +20 ppbv (~ +20 %), but given that under these conditions the TES/aircraft comparisons also show a small positive TES CO bias indicates that the overall model underprediction of CO is closer to ~ 10 % at 681 hPa (~ 3 km) during this period.
Interfacial layers on ice significantly influence air-ice chemical interactions. In solute-containing aqueous systems, a liquid brine may form upon freezing due to the exclusion of impurities from ...the ice crystal lattice coupled with freezing point depression in the concentrated brine. The brine may be segregated to the air-ice interface where it creates a surface layer, in micropockets, or at grain boundaries or triple junctions. We present a model for brines and their associated liquid layers in environmental ice systems that is valid over a wide range of temperatures and solute concentrations. The model is derived from fundamental equlibrium thermodynamics and takes into account nonideal solution behavior in the brine, partitioning of the solute into the ice matrix, and equilibration between the brine and the gas phase for volatile solutes. We find that these phenomena are important to consider when modeling brines in environmental ices, especially at low temperatures. We demonstrate its application for environmentally important volatile and nonvolatile solutes including NaCl, HCl, and HNO3. The model is compared to existing models and experimental data from literature where available. We also identify environmentally relevant regimes where brine is not predicted to exist, but the QLL may significantly impact air-ice chemical interactions. This model can be used to improve the representation of air-ice chemical interactions in polar atmospheric chemistry models.
It is not clear why some plaque ruptures lead to acute coronary syndromes (ACS) but others do not.
We analyzed 80 plaque ruptures in 74 patients and compared culprit lesions of ACS patients with ...nonculprit lesions of ACS patients and lesions of non-ACS patients; both culprit and nonculprit plaque ruptures were studied in 6 of 54 ACS patients. Intravascular ultrasound findings suggesting thrombus were observed more frequently in culprit lesions of ACS patients (n=35) compared with nonculprit lesions of ACS patients (n=19) and lesions of non-ACS patients (n=26): 60% versus 32% versus 8% (P<0.001). At the minimal lumen site, smaller lumen areas (3.3+/-1.5 versus 5.4+/-2.6 versus 6.1+/-2.0 mm2, P<0.001) and greater area stenosis (61+/-15% versus 50+/-14% versus 46+/-18%, P=0.002) and plaque burden (80+/-8% versus 71+/-8% versus 69+/-10%, P<0.001) were observed in culprit lesions of ACS patients compared with nonculprit lesions of ACS patients and lesions of non-ACS patients. Lesions were longer (18.7+/-6.4 versus 154.9+/-6.1 versus 12.0+/-4.9 mm, P<0.001) and rupture site remodeling indices were greater (1.26+/-0.21 versus 1.24+/-0.21 versus 1.09+/-0.05, P=0.002). Independent predictors of culprit plaque ruptures in ACS patients were smaller minimum lumen areas (P=0.02) and presence of thrombus (P=0.01).
Ruptured plaques in culprit lesions of ACS patients have smaller lumens; greater plaque burdens, area stenosis, and remodeling indices; and more thrombus. Plaque rupture itself does not lead to symptoms. The association of plaque rupture with a smaller lumen area and/or thrombus formation causes lumen compromise and leads to symptoms.
Nitric acid in air is formed by atmospheric reactions of oxides of nitrogen and is removed primarily through deposition to surfaces, either as the gas or after conversion to particulate nitrate. Many ...of the surfaces and particles have organic coatings, but relatively little is known about the interaction of nitric acid with organic films. We report here studies of the interaction of gaseous HNO
3
with a self-assembled monolayer (SAM) formed by reacting 7-octenyltrichlorosilane H
2
C&z.dbd;CH(CH
2
)
6
SiCl
3
with the surface of a germanium infrared-transmitting attenuated total reflectance (ATR) crystal that was coated with a thin layer of silicon oxide (SiO
x
). The SAM was exposed at 298 ± 2 K to dry HNO
3
in a flow of N
2
, followed by HNO
3
in humid N
2
at a controlled relative humidity (RH) between 20-90%. For comparison, similar studies were carried out using a similar crystal without the SAM coating. Changes in the surface were followed using Fourier transform infared spectroscopy (FTIR). In the case of the SAM-coated crystal, molecular HNO
3
and smaller amounts of NO
3
−
ions were observed on the surface upon exposure to dry HNO
3
. Addition of water vapor led to less molecular HNO
3
and more H
3
O
+
and NO
3
−
complexed to water, but surprisingly, molecular HNO
3
was still evident in the spectra up to 70% RH. This suggests that part of the HNO
3
observed was initially trapped in pockets within the SAM and shielded from water vapor. After increasing the RH to 90% and then exposing the film to a flow of dry N
2
, molecular nitric acid was regenerated, as expected from recombination of protons and nitrate ions as water evaporated. The nitric acid ultimately evaporated from the film. On the other hand, exposure of the SAM to HNO
3
and H
2
O simultaneously gave only hydronium and nitrate ions. Molecular dynamics simulations of defective SAMs in the presence of HNO
3
and water predict that nitric acid intercalates in defects as a complex with a single water molecule that is protected by alkyl chains from interacting with additional water molecules. These studies are consistent with the recently proposed hydrophobic nature of HNO
3
. Under atmospheric conditions, if HNO
3
is formed in organic layers on surfaces in the boundary layer,
e.g.
through NO
3
or N
2
O
5
reactions, it may exist to a significant extent in its molecular form rather than fully dissociated to nitrate ions.
New experimental and theoretical insights into the interaction of nitric acid with an organic film are provided.
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