1,710 research outputs found
Thin film thermoelectric devices as thermal control coatings: A study
Peltier effect, Thomson effect, and Seeback effect are utilized in design of thermal control coating that serves as versatile means for controlling heat absorbed and radiated by surface. Coatings may be useful in extreme temperature environment enclosures or as heat shields
Screening of cryptic species among clinical Aspergillus isolates collected during one year period in a Portuguese reference laboratory
Objectives: Correct identification of Aspergillus species is important given that sibling species may show variable susceptibilities to multiple antifungal drugs and also because sharper definition of species may facilitate epidemiological studies. Thus, we screened Aspergillus clinical isolates from Portuguese hospitals to determine which, if any, of the cryptic species of Aspergillus were involved in patient infections.
Methods: Over a one year period, Aspergillus isolates from Portuguese health institutions were collected. These isolates were identified on the basis of microscopic morphology and through the use of molecular tools. Genomic DNA was prepared from each isolate and the sequencing of the Internal Transcribed Spacers (ITS) regions, specifically the ITS1 and ITS2 non-coding regions flanking the 5.8S rDNA was used to determine the species complex, whereas β-tubulin and calmodulin sequencing was done to achieve the correct species identification.
Results: Over the study period, 57 Aspergillus isolates from clinical samples were collected from 10 Portuguese health institutions. According to the morphological observations, 29 isolates were identified as Aspergillus fumigatus, 11 A. flavus, 8 A. niger, 3 A. nidulans, 2 A. terreus, 2 A. candidus and 2 Aspergillus sp. Among those isolates, six species-complexes were detected by ITS sequencing, and were distributed as follows: fumigati (50.1%), flavi (21.0%), nigri (15.8%), terrei (5.3%), nidulantes (3.6%) and versicolores (3.6%). β-tubulin and calmodulin sequencing resulted in ten (17.5%) cryptic species being identified among the 57 isolates. Six of those isolates belonged to the nigri complex (A. brasiliensis, A. awamorii and A. tubigensis), two to the versicolores complex (A. sidowii and A. fructus), one to the fumigati complex (A. lentulus) and one to the nidulantes complex (Emmericella echinulata).
Conclusion: With rigorous application of molecular tools, cryptic species of Aspergillus are not uncommon in the clinic. The identification of cryptic species among the collected clinical isolates of Aspergillus alerts the clinician to isolates with reduced susceptibilities to antifungal drugs and emphasizes a correct identification to species level
Identification of Aspergillus cryptic species in hospital environment
Selected hospital wards, housing patients at higher risk to develop invasive fungal infections, were screened in order to understand the epidemiology and distribution of Aspergillus, especially regarding the presence of cryptic species.Aspergillus species were identified by b-tubulin and calmodulin sequencing, and a high percentage of cryptic species (i.e., not sensu stricto) was found (59%). Sections Usti, Versicolores and Circumdati harbored the highest proportion of cryptic species [100% (4/4), 95% (19/20) and 90% (9/10),
respectively].The high number of cryptic species found raises concerns about the possible reduced susceptibility to antifungals of hospital environmental Aspergillus isolates. These data reinforce the
importance of hospital air and surface monitoring, mainly in immunocompromised patients’ wards
Surveillance of environmental fungi, with focus on Aspergillus, in a Portuguese Central Hospital.
Objectives: Because immunocompromised patients are more prone to acquire nosocomial infections caused by fungi isolated from the environment, e.g. Aspergillus, this study aimed to screen the hospital environment for the presence of fungi and to understand their epidemiology in the different hospital wards analyzed.
Methods: During one-year period, four seasonal samplings, i.e., air and hard surface, were performed. A total of 101 air samples and 99 surface samples were collected from the Hematology, Oncology, and Intensive Care Unit (ICU) wards of a Portuguese Central Hospital. Aspergillus isolates were plated for growth as single colonies on malt extract agar with chloramphenicol to check the colony purity and observe colonial morphology. The universal fungal primers ITS1 and ITS4 were used to amplify DNA from all Aspergillus isolates, amplimers were sequenced, and isolates identified to the species-complex level. Statistical analyses were done using SPSS v15.0 program for Windows.
Results: Aspergillus was the most frequently recovered fungal genus (20.9%), followed by Cladosporium (18.7%), and Penicillium (17.2%). Thirty-five Aspergillus isolates were collected from the wards with hematological patients (bone marrow transplant and hemato-oncology wards), whereas 15 isolates were recovered from ICU. Among Aspergillus isolates from the hospital environment, those belonging to the species-complexes of versicolores (n = 26; 32.5%), nigri (n = 12; 15.0%), flavi (n = 11; 13.7%), and circumdati (n = 6; 7.5%) dominated. Hemato-Oncology was the ward with higher fungal counts, whereas the bone marrow transplant ward, which is protected by HEPA-filtration of the supply air, showed the lowest numbers in all sampling periods. A significant association (p = 0.001) was found between the season and the Aspergillus complexes isolated, with spring and summer having a larger number of different species-complexes detected in the hospital´s air and on the surfaces. Nevertheless, air counts showed that the autumn was the season with the highest proportion of Aspergillus (one third of the total number of fungi detected). This could be due in part to the presence of construction work near these wards.
Conclusion: The knowledge of the epidemiology of environmental fungi in each hospital may allow the establishment of preventive or corrective measures to decrease nosocomial fungal infections
Intergenerational change and familial aggregation of body mass index
The relationship between parental BMI and that of their adult offspring, when increased adiposity can become a clinical issue, is unknown. We investigated the intergenerational change in body mass index (BMI) distribution, and examined the sex-specific relationship
between parental and adult offspring BMI. Intergenerational
change in the distribution of adjusted BMI in 1,443
complete families (both parents and at least one offspring)
with 2,286 offspring (1,263 daughters and 1,023 sons) from
the west of Scotland, UK, was investigated using quantile
regression. Familial correlations were estimated from
linear mixed effects regression models. The distribution
of BMI showed little intergenerational change in the normal
range (\25 kg/m2), decreasing overweightness (25–
\30 kg/m2) and increasing obesity (C30 kg/m2). Median
BMI was static across generations in males and decreased
in females by 0.4 (95% CI: 0.0, 0.7) kg/m2; the 95th percentileincreased by 2.2 (1.1, 3.2) kg/m2 in males and 2.7
(1.4, 3.9) kg/m2 in females. Mothers’ BMI was more
strongly associated with daughters’ BMI than was fathers’
(correlation coefficient (95% CI): mothers 0.31 (0.27,
0.36), fathers 0.19 (0.14, 0.25); P = 0.001). Mothers’ and
fathers’ BMI were equally correlated with sons’ BMI
(correlation coefficient: mothers 0.28 (0.22, 0.33), fathers
0.27 (0.22, 0.33). The increase in BMI between generations
was concentrated at the upper end of the distribution. This,
alongside the strong parent-offspring correlation, suggests that the increase in BMI is disproportionally greater among
offspring of heavier parents. Familial influences on BMI among middle-aged women appear significantly stronger from mothers than father
Size-structured populations: immigration, (bi)stability and the net growth rate
We consider a class of physiologically structured population models, a first
order nonlinear partial differential equation equipped with a nonlocal boundary
condition, with a constant external inflow of individuals. We prove that the
linearised system is governed by a quasicontraction semigroup. We also
establish that linear stability of equilibrium solutions is governed by a
generalized net reproduction function. In a special case of the model
ingredients we discuss the nonlinear dynamics of the system when the spectral
bound of the linearised operator equals zero, i.e. when linearisation does not
decide stability. This allows us to demonstrate, through a concrete example,
how immigration might be beneficial to the population. In particular, we show
that from a nonlinearly unstable positive equilibrium a linearly stable and
unstable pair of equilibria bifurcates. In fact, the linearised system exhibits
bistability, for a certain range of values of the external inflow, induced
potentially by All\'{e}e-effect.Comment: to appear in Journal of Applied Mathematics and Computin
Organization theory and military metaphor: time for a reappraisal?
A ‘conventional’ use of military metaphor would use it to convey attributes such as hierarchical organization, vertical communication and limited autonomy. This is often used in contrast to a looser form of organization based on the metaphor of the network. However, this article argues that military practice is more complex, with examples of considerable autonomy within the constraints of central direction. It is suggested that not only might this be a more useful metaphor for many contemporary organizations, but also that simplistic uses of military metaphor divert our attention away from the functions that management hierarchies play. The discussion is embedded within a critical realist account of metaphor, arguing for both its value and the need for its further development
Model for eukaryotic tail-anchored protein binding based on the structure of Get3
The Get3 ATPase directs the delivery of tail-anchored (TA) proteins to the endoplasmic reticulum (ER). TA-proteins are characterized by having a single transmembrane helix (TM) at their extreme C terminus and include many essential proteins, such as SNAREs, apoptosis factors, and protein translocation components. These proteins cannot follow the SRP-dependent co-translational pathway that typifies most integral membrane proteins; instead, post-translationally, these proteins are recognized and bound by Get3 then delivered to the ER in the ATP dependent Get pathway. To elucidate a molecular mechanism for TA protein binding by Get3 we have determined three crystal structures in apo and ADP forms from Saccharomyces cerevisae (ScGet3-apo) and Aspergillus fumigatus (AfGet3-apo and AfGet3-ADP). Using structural information, we generated mutants to confirm important interfaces and essential residues. These results point to a model of how Get3 couples ATP hydrolysis to the binding and release of TA-proteins
Assigning stranded bottlenose dolphins to source stocks using stable isotope ratios following the Deepwater Horizon oil spill
The potential for stranded dolphins to serve as a tool for monitoring free-ranging populations would be enhanced if their stocks of origin were known. We used stable isotopes of carbon, nitrogen, and sulfur from skin to assign stranded bottlenose dolphins Tursiops truncatus to different habitats, as a proxy for stocks (demographically independent populations), following the Deepwater Horizon oil spill. Model results from biopsy samples collected from dolphins from known habitats (n = 205) resulted in an 80.5% probability of correct assignment. These results were applied to data from stranded dolphins (n = 217), resulting in predicted assignment probabilities of 0.473, 0.172, and 0.355 to Estuarine, Barrier Island (BI), and Coastal stocks, respectively. Differences were found west and east of the Mississippi River, with more Coastal dolphins stranding in western Louisiana and more Estuarine dolphins stranding in Mississippi. Within the Estuarine East Stock, 2 groups were identified, one predominantly associated with Mississippi and Alabama estuaries and another with western Florida. δ15N values were higher in stranded samples for both Estuarine and BI stocks, potentially indicating nutritional stress. High probabilities of correct assignment of the biopsy samples indicate predictable variation in stable isotopes and fidelity to habitat. The power of δ34S to discriminate habitats relative to salinity was essential. Stable isotopes may provide guidance regarding where additional testing is warranted to confirm demographic independence and aid in determining the source habitat of stranded dolphins, thus increasing the value of biological data collected from stranded individuals.Publisher PDFPeer reviewe
The Block Beautification Project: Three Years Later
This article provides an update to the 2017 piece, Community Based Project: The Block Beautification Project: One Artist’s Work to Help Make West Baltimore Beautiful, sharing the status of the West Baltimore art installations three years later
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