Aerial Conditions Research Articles

Investigation of Aspergillus fumigatus biofilm formation by various “omics” approaches

In the lung, Aspergillus fumigatus usually forms a dense colony of filaments embedded in a polymeric extracellular matrix called biofilm (BF). This extracellular matrix embeds and glues hyphae together and protects the fungus from an outside hostile environment. This extracellular matrix is absent in fungal colonies grown under classical liquid shake conditions (PL), which were historically used to understand A. fumigatus pathobiology. Recent works have shown that the fungus in this aerial grown BF-like state exhibits reduced susceptibility to antifungal drugs and undergoes major metabolic changes that are thought to be associated to virulence. These differences in pathological and physiological characteristics between BF and liquid shake conditions suggest that the PL condition is a poor in vitro disease model. In the laboratory, A. fumigatus mycelium embedded by the extracellular matrix can be produced in vitro in aerial condition using an agar-based medium. To provide a global and accurate understanding of A. fumigatus in vitro BF growth, we utilized microarray, RNA-sequencing, and proteomic analysis to compare the global gene and protein expression profiles of A. fumigatus grown under BF and PL conditions. In this review, we will present the different signatures obtained with these three “omics” methods. We will discuss the advantages and limitations of each method and their complementarity.

Rolling with the flow: Bumblebees flying in unsteady wakes

Our understanding of how variable wind in natural environments affects flying insects is limited because most studies of insect flight are conducted in either smooth flow or still air conditions. Here, we investigate the effects of structured, unsteady flow (the von Karman vortex street behind a cylinder) on the flight performance of bumblebees (Bombus impatiens). Bumblebees are 'all-weather' foragers and thus frequently experience variable aerial conditions, ranging from fully mixed, turbulent flow to unsteady, structured vortices near objects such as branches and stems. We examined how bumblebee flight performance differs in unsteady versus smooth flow, as well as how the orientation of unsteady flow structures affects their flight performance, by filming bumblebees flying in a wind tunnel under various flow conditions. The three-dimensional flight trajectories and orientations of bumblebees were quantified in each of three flow conditions: (1) smooth flow, (2) the unsteady wake of a vertical cylinder (inducing strong lateral disturbances) and (3) the unsteady wake of a horizontal cylinder (inducing strong vertical disturbances). In both unsteady conditions, bumblebees attenuated the disturbances induced by the wind quite effectively, but still experienced significant translational and rotational fluctuations as compared with flight in smooth flow. Bees appeared to be most sensitive to disturbance along the lateral axis, displaying large lateral accelerations, translations and rolling motions in response to both unsteady flow conditions, regardless of orientation. Bees also displayed the greatest agility around the roll axis, initiating voluntary casting maneuvers and correcting for lateral disturbances mainly through roll in all flow conditions. Both unsteady flow conditions reduced the upstream flight speed of bees, suggesting an increased cost of flight in unsteady flow, with potential implications for foraging patterns and colony energetics in natural, variable wind environments.

Quantum mechanics applied to the dynamic assessment of a cluster of water particles in sprinkler irrigation

The problem of liquid droplets crossing a gas is common to many scientific and technical issues and, in particular, also to sprinkler irrigation; thus, when designing a sprinkler irrigation system, it is essential to fully understand how droplets mechanically behave during their flight and how a mathematical modeling can cope with all the variables affecting one another during such a complicate thermal fluid dynamic process. In the thematic scientific literature, the classic approach has been recently challenged by an alternative quantum one, provided in two different formulations referring to a single droplet dynamics: one focusing on a full description of the process (time-dependent Schrodinger equation); the other focusing on the discovery of an easier-to-use method (scale relativity theory); both allowing for a broader microscopical insight of the actual mechanics of single water droplets in sprinkler irrigation. The present contribution is aimed at developing the quantum procedure extending it to a cluster of water particles, as one droplet during its aerial flight conditions the others, which are in its vicinity and vice versa.

Photosynthetic performance in aquatic and terrestrial colonies of Nostoc flagelliforme (Cyanophyceae) under aquatic and aerial conditions

The photosynthetic capacity of aquatic and terrestrial colonies of Nostoc flagelliforme was measured in both submerged and emerged states to investigate their response to full hydration and degrees of desiccation. For both colonies, photosynthesis under aquatic conditions was higher than under terrestrial conditions. During the course of immersion, net maximal photosynthesis rate (Pmax) of both types of colonies increased from the beginning of desiccation (fully hydrated), reached highest at water loss of 37–40%, and then decreased with further water loss. Both forms of colonies exhibited a high tolerance to desiccation. Even at 80% water loss they maintained positive CO2 uptake rates. For every treatment, the submerged colonies had a higher photosynthetic carbon fixation capacity than the terrestrial ones where the photochemical efficiency of colonies only decreased significantly when water loss went beyond 50%. The activity can still be maintained even at a water loss of 82%. Due to its high photosynthetic rate and tolerance of desiccation, the aquatic colony has a great potential as a “seeds” resource for cultivation in terrestrial environments.

Effects of light quality on leaf morphogenesis of a heterophyllous amphibious plant, Rotala hippuris

For heterophyllous amphibious plants that experience fluctuating water levels, it is critical to control leaf development precisely in response to environmental cues that can serve as a quantitative index of water depth. Light quality can serve as such a cue because the ratio of red light relative to far-red light (R/FR) increases and blue-light intensity decreases with increasing water depth. Growth experiments were conducted to examine how R/FR and blue-light intensity alter leaf morphology of a heterophyllous amphibious plant, Rotala hippuris. Using combinations of far red (730 nm), red (660 nm) and blue (470 nm) light-emitting diodes (LEDs), growth experiments were used to quantitatively evaluate the effects of the R/FR ratio and blue-light intensity on leaf morphology. Under the natural light regime in an outside growth garden, R. hippuris produced distinct leaves under submerged and aerial conditions. R/FR and blue-light intensity were found to markedly affect heterophyllous leaf formation. Higher and lower R/FR caused leaf characters more typical of submerged and aerial leaves, respectively, in both aerial and submerged conditions, in accordance with natural distribution of leaf types and light under water. High blue light caused a shift of trait values toward those of typical aerial leaves, and the response was most prominent under conditions of R/FR that were expected near the water surface. R/FR and blue-light intensity provides quantitative cues for R. hippuris to detect water depth and determine the developmental fates of leaves, especially near the water surface. The utilization of these quantitative cues is expected to be important in habitats where plants experience water-level fluctuation.

Associations in ephemeral systems: the lack of trophic relationships between sandhoppers and beach wrack

In ephemeral systems, material subsidies can play a key role in the persistence and connectivity of populations, especially if the organisms living within them are trophically dependent on imported resources. Sandy beaches are heavily subsidized by organic material of both terrestrial and marine origin. For highly mobile supratidal fringe species, such as amphipods, which are marine but with a high tolerance of aerial conditions, such material potentially provides both food and shelter. We investigated the relationship between beach wrack and amphipods by examining the trophic contribution of allochthonous food sources to sandhopper diets using stable isotope analysis. Replicate samples of the sandhopper Talorchestia capensis and several types of beach wrack (including seagrass, wood and different macrophytes) colonized by these amphipods were collected from 11 sites within one biogeographical region along the south coast of South Africa. Analysis of variance showed that the δ13C and δ15N signatures of sandhoppers were significantly affected by the type of wrack with which they were associated, but stable isotope mixing models showed that there was no close relationship between T. capensis diet and the material under which they were found. Thus sandhopper isotope signatures differed with wrack type, but were not clearly derived from wrack. This was interpreted as an indication that amphipod feeding was extremely opportunistic, with different sandhopper populations feeding at different trophic levels (based on δ15N signatures) and obtaining their δ13C signatures from material associated with specific wrack types, rather than directly from the wrack itself or from imported suspended particulate material. These results suggest alternative links in sandy beach food webs, with amphipods obtaining their carbon indirectly from wrack via bacterial communities that are specific to different types of imported material.

Air temperature and winter mortality: Implications for the persistence of the invasive mussel, Perna viridis in the intertidal zone of the south-eastern United States

Global climate change and invasive species represent two of the biggest threats to the environment. Biological communities are responding to global climate change through poleward shifts in distribution, and changes in abundance and phenology of both native and non-native species. An increase in the frequency and magnitude of extreme weather events is predicted with global climate change. Much is known about mortality events of marine organisms in relation to warm thermal stress with relatively little known about cold thermal stress, particularly in the tropics. Intertidal species are particularly susceptible to fluctuations in aerial conditions and many are considered indicators of climate change. Perna viridis is a recent invader to the United States where it fouls hard substrates and soft sediment habitats. During winter 2007/08, a mortality event was observed for P. viridis across Tampa Bay, Florida. This mortality event coincided with extreme weather conditions when air temperatures dropped below 2 °C for a period of 6 h during low water. The minimum air temperature recorded was 0.53 °C. During this period water temperature remained relatively constant (~ 20 °C). We provide strong evidence supporting the hypothesis that thermal stress relating to exposure to cold air temperatures during emersion was the primary factor underpinning the mortality event. Similar mortality events occurred in 2009 and 2010, also coinciding with prolonged exposure to low air temperatures. In the short term, weather may be responsible for the temporary trimming back of populations at the edge of their geographic range but in the longer-term, it is expected that climate warming will trigger the poleward movement of both native and non-native species potentially facilitating biotic homogenisation of marine communities. The challenge now is to devise adaptive management strategies in order to mitigate any potential negative impacts to native biodiversity.

Aspergillus fumigatusbiofilms in the clinical setting

We discuss in this work the role of Aspergillus biofilms in the clinical setting by reviewing the most recent findings on this topic. Aspergillus fumigatus can produce in vitro an extracellular hydrophobic matrix with typical biofilm characteristics under all static conditions tested, i.e., agar media, polystyrene and bronchial epithelial cells. Under static conditions the mycelial growth is greater than in shaken, submerged conditions. The extracellular matrix (ECM) is composed of galactomannan, α-1,3-glucans, monosaccharides and polyols, melanin and proteins including major antigens and hydrophobins. Typical biofilm structures were observed in the aspergillomas from two patients and in a murine model of invasive pulmonary aspergillosis. The results indicate that α-1,3-glucans plays a predominant role in the agglutination of the hyphae together in aerial conditions, and that nutrient starvation was responsible for mycelial death in aspergilloma. Melanin was produced during the infection, suggesting that this pigment is necessary for lung tissue invasion. All antifungal drugs are significantly less effective when A. fumigatus is grown under biofilm vs. planktonic conditions. Chronic persistence of a unique genotype of A. fumigatus in the respiratory tract of CF-patients and the presence of an ECM in vivo may have some therapeutical application for aspergillosis. The most appropriate antifungal drug should not be selected only on the basis of its efficiency to kill in vitro grown fungal cells, but also on its ability to penetrate the ECM.

Broadening the Horizons of Scene Gist Recognition: Aerial and Ground-based Views

Numerous studies in the last decade have used ground-based views of scenes to investigate the process of scene gist recognition. Conversely, few if any studies have investigated scene gist recognition of aerial (i.e., satellite) views. This study asks the question, how much of what we know about scene gist recognition from ground-based views directly translates to aerial views? Fifty-two participants were randomly assigned to Aerial and Ground-based conditions, with processing times (SOA) and scene categories varied within-subjects. Stimuli were monochrome photographs from 10 categories: 5 Natural: coast, desert, forest, mountain, river; 5 Man-made: airport, city, golf-course, residential, stadium. Aerial images were from Google Earth©. Both target and mask images were presented for 24 ms, with SOAs of 24-94 ms plus a no-mask condition. Participants then chose between all 10 categories. As predicted, ground-based views were recognized more accurately than aerial views. However, contrary to predictions, aerial view recognition did not benefit more from additional processing time than ground-based view recognition. Aerial view performance with no mask was worse than ground-based view performance at 24 ms SOA. Thus, gist perception of aerial views is more data (information) limited than resource (time) limited, perhaps because they are “accidental views” (Biederman, 1987). An additional analysis collapsed all 10 basic level categories into 2 superordinate level “Natural” and “Man-made” categories. For ground-based views, Natural categories were consistently high, whereas Man-made categories benefited from additional processing time. However, for aerial views, both Natural and Man-made categories benefited equally from additional processing time. Nevertheless, confusion matrices for the 10 basic level categories and responses showed a correlation of .80 across the Aerial and Ground-based views, suggesting that discriminability between categories is similar across aerial and ground-based views. Further research will investigate what information both aerial and ground-based views contain, and what information aerial views lack.

ChemInform Abstract: An Efficient and Recyclable Water‐Soluble Cyclopalladated Complex for Aqueous Suzuki Reactions under Aerial Conditions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Heterogeneous Suzuki and copper-free Sonogashira cross-coupling reactions catalyzed by a reusable palladium(II) complex in water medium

An efficient heterogeneous Pd(II) azo complex catalyst for Suzuki and Sonogashira cross-coupling reaction has been developed. The catalyst showed an excellent activity for these reactions in water medium under aerial conditions. A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki–Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding cross-coupling products in excellent yields (83–100% yield for Suzuki reaction and 68–96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.

Isolation and structural characterization of 1,5-benzodiazepinium cation in an inorganic–organic hybrid compound [C 12H 17N 2] 3[Bi 2Cl 9]·2EtOH

The compound [C 12H 17N 2] 3[Bi 2Cl 9]·2EtOH ( 1) has been synthesized from bismuth trichloride and o-phenylenediamine (opda) in ethanol at an aerial ambient condition. This preparation includes the conversion of opda to 2,3-dihydro-1H-1,5-benzodiazepinium cation through its reaction with acetone that is formed in situ from aerial ethanol oxidation. Compound 1 crystallizes in triclinic system (space group P−1). In the crystal structure of 1, the supramolecular hydrogen bonding interactions between [Bi 2C 9] 3− and [C 12H 17N 2] + play an important role in the stabilization of cationic form of 2,3-dihydro-1H-1,5-benzodiazepine and in obtaining emission signals of the organic moiety, which is otherwise not emissive. Compound [C 12H 17N 2] 3[Bi 2Cl 9]·2(2-PrOH) ( 2), that has been isolated from 2-propanol (instead of ethanol), is isostructural with compound 1.

Exposure to water increased pollen longevity of pondweed (Potamogeton spp.) indicates different mechanisms ensuring pollination success of angiosperms in aquatic habitat

Pollen longevity in seven Potamogeton species representing different pollination systems (anemophily, epihydrophily and hydroautogamy) was assessed both under aerial condition and in contact with water to investigate how water impacts the sexual reproduction in these aquatic taxa. Stainability of pollen with MTT was considered as an indicator of pollen viability. The half-life of pollen longevity was calculated using exponential decay regression. Overall, pollen viability decreased relatively rapidly with time. Pollen grains of obligate anemophilic species had lower initial viability and shorter half-lives than those of facultative anemophilic species. Pollen in these latter species may take more time to reach the stigma. The pollen of Potamogeton may be categorized as partially hydrated pollen owing to its generally spherical shape and lack of furrows, rapid loss of viability, and fast pollen tube initiation. The half-life is positively correlated with pollen size. Smaller-sized grains are at greater risk of desiccation than larger grains. In contrast with the situation observed in most terrestrial angiosperms, contact with water increases pollen longevity in Potamogeton species. In our present study the half-lives of pollen longevity of Potamogeton species in which the pollen had come into contact with water (mean of 10.65 h) were markedly higher than those under aerial conditions (mean of 5.79 h, t = 2.622, P = 0.039). The results of our study contradict a widely held belief that water is detrimental to pollen viability in angiosperms and furthermore indicate that close proximity to water results in selection for wettability. The transition to a hydrated status together with its morphology, make Potamogeton pollen more adapted to the aquatic environment and thus serves to ensure reproductive process. Results of our present study may have direct implications for understanding the evolution of the sexual reproductive system in aquatic angiosperms.

An efficient and recyclable water-soluble cyclopalladated complex for aqueous Suzuki reactions under aerial conditions

Several water-soluble cyclopalladated complexes with five- or six-membered rings have been prepared as air-stable solids from Schiff base ligands bearing an N-phenyl sulfonate groups. Cyclopalladated complexes with six-membered rings show high catalytic efficiency for the Suzuki reactions of aryl bromides with phenylboronic acid in aqueous solvents under mild conditions. Palladium complex 1 can be used for five reaction cycles in high conversions for the Suzuki reactions in neat water without additives. The catalytic process for the Suzuki couplings is proved by TEM analysis to proceed on Pd(0) nanoparticles. Surfactant-protected palladium nanoparticles present lower activities and poorer recyclability for the coupling reactions than those generated in situ without additives.

Branchial ammonia excretion in the Asian weatherloach Misgurnus anguillicaudatus

The weatherloach, Misgurnus anguillicaudatus, is a freshwater, facultative air-breathing fish that lives in streams and rice paddy fields, where it may experience drought and/or high environmental ammonia (HEA) conditions. The aim of this study was to determine what roles branchial Na +/K +-ATPase, H +-ATPase, and Rhcg have in ammonia tolerance and how the weatherloach copes with ammonia loading conditions. The loach's high ammonia tolerance was confirmed as was evident from its high 96 h LC 50 value and high tissue tolerance to ammonia. The weatherloach does not appear to make use of Na +/NH 4 +-ATPase facilitated transport to excrete ammonia when exposed to HEA or to high environmental pH since no changes in activity were observed. Using immunofluorescence microscopy, distinct populations of vacuolar (V)-type H +-ATPase and Na +/K +-ATPase immunoreactive cells were identified in branchial epithelia, with apical and basolateral staining patterns, respectively. Rhesus C glycoprotein (Rhcg1), an ammonia transport protein, immunoreactivity was also found in a similar pattern as H +-ATPase. Rhcg1 (Slc42a3) mRNA expression also increased significantly during aerial exposure, although not significantly under ammonia loading conditions. The colocalization of H +-ATPase and Rhcg1 to the similar non-Na +/K +-ATPase immunoreactive cell type would support a role for H +-ATPase in ammonia excretion via Rhcg by NH 4 + trapping. The importance of gill boundary layer acidification in net ammonia excretion was confirmed in this fish; however, it was not associated with an increase in H +-ATPase expression, since tissue activity and protein levels did not increase with high environmental pH and/or HEA. However the V-ATPase inhibitor, bafilomycin, did decrease net ammonia flux whereas other ion transport inhibitors (amiloride, SITS) had no effect. H +-ATPase inhibition also resulted in a consequent elevation in plasma ammonia levels and a decrease in the net acid flux. In gill, aerial exposure was also associated with a significant increase in membrane fluidity (or increase in permeability) which would presumably enhance NH 3 permeation through the plasma membrane. Taken together, these results indicate the gill of the weatherloach is responsive to aerial conditions that would aid ammonia excretion.

Study on the Fault Diagnosis Technique of Aerial Camera Exposure Board Based on Petri Net

Because of the mechanical situation, aerial carrier condition, environment condition and usage maintenance of the aerial camera, faults always occur. So it is necessary to check and maintain the aerial camera on the ground, and the interior structure of the aerial camera is very complex, and the aerial camera is composed by many circuit boards, and the checking must be performed from the whole camera to each component. Aiming at the demands of aerial camera fault diagnosis, the board level fault diagnosis system of aerial camera was developed in the article. The failure mode of the exposure board in the aerial camera electric control system was completely analyzed, and the exposure board fault board model based on Petri net was established, and the dynamical transition of the system status was solved by the relational matrix method, and the TPS program of the exposure board was compiled, and the fault diagnosis of the exposure board was primarily actualized in the article.

Elemental Copper Catalyzed Stereoselective Aminobromination

Stereoselective aminohalogenation is a challenging problem for organic synthesis. In this report, a convenient procedure for ­aminobromination of α,β-unsaturated ketones catalyzed by copper powder is described. The method can provide the aminobromination products in almost quantitative yields and complete anti-selectivity with only 1 mol% catalyst loading under aerial conditions. Copper metal was also proven to be more efficient than CuI in this ­transformation.

Effects of Spray Mixtures on Droplet Size under Aerial Application Conditions and Implications on Drift

There is a concerted effort within the spray application industry to develop and implement a Drift Reduction Technology (DRT) Program, which would encourage applicators to adopt technologies that are shown to mitigate off-target movement of sprays. The use of simulated or mimic sprays for atomization studies in high-speed wind tunnels allow researchers to limit the amount of active ingredients used in spray tests and facilitate the testing and certification of DRTs. However, it is important that these simulated and mimic sprays have the same physical and atomization characteristics of sprays containing active ingredients. Studies were conducted to compare droplet size generation from four spray formulations, one of which was an active ingredient and three which were potential mimics and to use the collected data to examine an application management practice as a potential DRT. These sprays were atomized using two nozzles placed in high-speed airstreams (45-63 m/s in 2-m/s increments) in a wind tunnel and the droplet spectra measured via a laser diffraction instrument.

INTERTIDAL MUSSELS EXHIBIT ENERGETIC TRADE-OFFS BETWEEN REPRODUCTION AND STRESS RESISTANCE

Life-history theory suggests that trade-offs exist between fitness components, with organisms balancing investment in reproduction against survival and future reproduction. This study examined the influence of stress on physiological trade-offs in the dominant rocky intertidal mussel Mytilus californianus on the central Oregon coast, USA. The intertidal zone is a highly heterogeneous thermal environment that could lead to intrapopulation variation in stress responses. Stress increases along a vertical gradient, with higher physical stress occurring in the higher intertidal zone, both due to reduced feeding time and longer exposure to aerial conditions. Reproduction and carotenoid content were compared in mussels from the low and high vertical edges of the mussel bed. High-edge mussels invested less relative energy in reproduction and also spawned all of their gametes in the early summer, whereas low-edge mussels continuously spawned small batches of gametes throughout the year. High-edge mussels accumulated high concentrations of carotenoid pigments into their gonadal tissues, potentially to protect gametes from damaging oxidative stress experienced during aerial exposure. A reciprocal transplant experiment revealed plastic responses in growth and reproduction to increased stress. In contrast, carotenoid content did not increase in response to stress, suggesting that carotenoids may not change rapidly or may not be easily lost or gained. Our results indicate that mussels exhibit physiological trade-offs and, under increased stress predicted from climate change scenarios, may allocate energy away from reproduction toward costly physiological defenses.

Effect of ammonia on weatherloach (Misgurnus anguillicaudatus) metabolism under aquatic and aerial conditions

Effect of ammonia on weatherloach (Misgurnus anguillicaudatus) metabolism under aquatic and aerial conditions