Prolonged Air Exposure Research Articles

The effect of dietary calcium inclusion on broiler gastrointestinal pH: Quantification and method optimization

There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed 1 of 2 experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d posthatch. Dietary Ca content had no significant effect on in situ pH, but it contributed toward variance in ex situ pH of both gizzard and duodenum digesta. Digesta pH read higher when the digesta was removed from the tract, but the amount of time the digesta was exposed to air did not affect the reading. Digesta pH read higher when measured at room temperature than when measured at 41°C; temperature made the strongest unique contribution to explaining variance in duodenum pH, and the second strongest contribution to explaining variance in gizzard pH, after diet. When water was added to the digesta, before pH determination, the pH of the digesta read higher (P < 0.001) than when measured in situ. The method that resulted in pH readings that were most representative of bird gastrointestinal environment was insertion of a pH probe directly into the gut lumen posteuthanasia, because measurement ex situ likely encourages dissociation of carbonic acid, the major buffer in the gastrointestinal tract, which causes pH to read to be higher than when measured in situ. This study shows that the method of pH measurement needs careful consideration to ensure the validity of the result.

Transcriptome Profiling of Archived Sectioned Formalin-Fixed Paraffin-Embedded (AS-FFPE) Tissue for Disease Classification

BackgroundArchived tissues from previously completed prospective trials represent invaluable resource for biomarker development. However, such specimens are often stored as sections on glass slides, in which RNA is severely degraded due to prolonged air exposure. We evaluated whether a proportion of archived sectioned formalin-fixed paraffin-embedded (AS-FFPE) tissues yield transcriptome profiles comparable to freshly cut (FC) FFPE tissues, which can be used for retrospective class prediction analysis.MethodsGenome-wide transcriptome profiles of 6 to 7-year-old AS-FFPE tissue sections (generated from 5 to 16-year-old blocks) of 83 hepatocellular carcinoma (HCC) and 47 liver cirrhosis samples were generated by using whole-genome DASL assay (Illumina) and digital transcript counting (nCounter) assay (NanoString), and gene signature-based prediction of HCC subclasses and prognosis was compared with previously generated FC-FFPE profiles from the same tissue blocks.ResultsRNA quality and assay reproducibility of AS-FFPE RNA were comparable to intermediate to poor quality FC-FFPE samples (RNA Integrity Number: up to 2.50, R-square for technical replicates: up to 0.93). Analyzable transcriptome profiles were obtained in 64 (77%) HCC and 36 (77%) cirrhosis samples. Statistically more confident predictions based on random resampling-based method (nearest template prediction) were obtained in 37 (58%) HCC and 13 (36%) cirrhosis samples. Predictions made in FC-FFPE profiles were reproduced in 36 (97%) HCC and 11 (85%) cirrhosis AS-FFPE profiles. nCounter assay was tested in 24 cirrhosis samples, which yielded confident prediction in 15 samples (63%), of which 10 samples (67%) showed concordant predictions with FC-FFPE profiles.ConclusionsAS-FFPE tissues yielded poorer quality RNA and transcriptome profiles compared to FC-FFPE tissues. Statistically more confident class prediction was feasible in 37 of 83 HCC samples and 13 of 47 cirrhosis samples. These results suggest that AS-FFPE tissues can be regarded as a resource for retrospective transcriptome-based class prediction analysis when they are the only available materials.

Blood lactate loads of redthroat emperor Lethrinus miniatus associated with angling stress and exhaustive exercise

Baseline, post-angling and maximum attainable blood lactate concentrations were measured for the fishery species redthroat emperor Lethrinus miniatus to gain insight into the condition of fish released following c. 30 s angling and <45 s air exposure. Mean ± S.D. baseline blood lactate was 1·5 ± 0·6 mmol l⁻¹, which increased and plateaued around 6 mmol l⁻¹ at 15-30 min post-angling. These values were significantly lower than those obtained from fish maximally exhausted with a prolonged chase and air exposure protocol following capture (10·9 ± 1·8 mmol l⁻¹), suggesting that L. miniatus is not maximally exhausted during standard angling practices.

Viability of Aquatic Plant Fragments following Desiccation

AbstractDesiccation following prolonged air exposure challenges survival of aquatic plants during droughts, water drawdowns, and overland dispersal. To improve predictions of plant response to air exposure, we observed the viability of vegetative fragments of 10 aquatic plant species (Cabomba caroliniana, Ceratophyllum demersum, Elodea canadensis, Egeria densa, Myriophyllum aquaticum, Myriophyllum heterophyllum, Myriophyllum spicatum, Potamogeton crispus, Potamogeton richardsonii, andHydrilla verticillata) following desiccation. We recorded mass loss, desiccation rate, and plant fragment survival across a range of air exposures. Mass loss accurately predicted viability of aquatic plant fragments upon reintroduction to water. However, similar periods of air exposure differentially affected viability between species. Understanding viability following desiccation can contribute to predicting dispersal, improving eradication protocols, and disposing of aquatic plants following removal from invaded lakes or contaminated equipment.

Localization of Antioxidant Enzymes in Human RBCs Upon Prolonged Air Exposure

Localization of Antioxidant Enzymes in Human RBCs Upon Prolonged Air Exposure

Growth and Chemical Stability of Copper Nanostructures on Cellulosic Fibers

AbstractThe design of paper products based on copper nanoparticles (NPs) is a challenge because of the intrinsic propensity of Cu to oxidize in contact with air. Here, a comparative study on the growth and chemical stability of Cu NPs in vegetable and bacterial cellulose is described for the first time. Furthermore, comparative studies were performed by using inorganic fillers of distinct dimensionality, Cu NPs and Cu nanowires (NWs), in both types of cellulose. Cu NWs were found to be more resistant to oxidation caused by prolonged air exposure than the Cu NPs. Notably, the cellulosic matrices behave differently for the growth or adsorption of the Cu nanofillers; bacterial cellulose fibers are the most efficient substrate to delay surface oxidation. The data support a role for bacterial cellulose in limiting the oxidation of Cu nanostructures that have been grown or blended in this type of matrix, hence opening up new perspectives for the development of electronic paper technologies that incorporate copper nanophases.

The effect of shot peening on the microstructure and properties of a near-alpha titanium alloy following high temperature exposure

The effect of shot peening on the microstructure, oxygen ingress and high-cycle fatigue properties of a near-α titanium alloy is investigated. Microstructural characterization of shot-peened material is performed through light microscopy, scanning electron microscopy and electron backscatter diffraction. Oxygen uptake during thermal exposure is analytically determined using secondary ion mass spectrometry. Shot peening leads to an increase in subsurface oxygen content following thermal exposure in air and the increased levels of oxygen content are accompanied by the precipitation of silicides along (or in close proximity to) the mechanical twin boundaries and in regions of high dislocation density. Preliminary fatigue data obtained through a staircase loading method show that a decrease in room temperature fatigue performance occurs in shot-peened material following prolonged thermal exposure in air at 650°C. The observed phenomena suggest that shot peening may be deleterious to the mechanical integrity of titanium alloy components that are subject to high temperature exposure in oxidizing environments.

XPS study of ZnO nanostructures prepared by laser ablation

The subject of the present work is different types of nanostructured ZnO films produced by pulsed laser deposition. The influence was investigated of the surface morphology on the physicochemical and optical properties of the nanostructured films. X-ray photoelectron spectroscopy was used to study the composition and chemical state of the nanostructured ZnO. The changes occurring on the surface of the films after prolonged exposure in air are considered in the light of practical applications of ZnO films. The change in the number of adsorbed species on the surface with the time affects the surface conductivity, the latter in turn modifying the optical properties of the samples.

Oxidation Behaviors of Two and Three Phase Mo-Si-B Alloys via Si Pack Cementation

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. In order to resolve the poor oxidation resistance of the alloy system, in this study, the oxidation behaviors of Si diffusion coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of the constituent of the phase combination of Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the produced MoSi2 phase, as a result of the coatings, give an excellent oxidation resistance at prolonged high temperature exposure in air. The oxidation behaviors of uncoated and Si coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

Direct correlation between work function of indium-tin-oxide electrodes and solar cell performance influenced by ultraviolet irradiation and air exposure

We report on reversible changes of the work function (WF) values of indium-tin-oxide (ITO) under prolonged ultraviolet (UV) and air exposure. The WF of ITO is reduced from 4.7 eV to 4.2 eV by photon absorption in ITO under UV illumination or an air mass 1.5 solar simulator (100 mW cm(-2)). Air or oxygen exposure is found to increase the WF of ITO (UV-exposed) to a value of 4.6 eV. These changes of ITO's WF lead to reversible variations of the performance of organic photovoltaic devices where ITO acts primarily as the electron collecting or hole collecting electrode. These variations can be reflected in the disappearance (or appearance) of an S-shaped kink in the J-V characteristics upon continuous UV or solar simulator illumination (or air exposure). This reversible phenomenon is ascribed to the adsorption and desorption of oxygen on the surface and grain boundaries of ITO. The use of surface modifiers to either decrease or increase the WF of ITO in organic photovoltaic devices with inverted and conventional geometries is also shown to be an effective route to stabilize the device performance under UV illumination.

The annual cycle of the pituitary-thyroid axis activity in healthy men under prolonged cold air exposure

The monthly investigations of military guards ((19.1 ? 0.9) years, n = 20) in northern European region (62?N lat.) that daily spent outdoors from 6 to 10 h were carried out during the year (from November to October). In examined subjects, the serum FT4 levels were high enough during all period of research espe-cially from April till October when the hormone levels exceeded norm. The concentration of serum FT3 was rather stable during the year and corresponded to the normal level. At the same time, the levels of total form of thyroid hormones (TT4 and TT3) displaced to lower limit of norm. Thus, staying outdoors of military guards in the North for all the year round is accompa-nied by activization of thyroid hormones use.

Plasma treatment methods to improve indium bump bonding via indium oxide removal

Flip chip hybridization, also known as bump bonding, is a packaging technique for microelectronic devices which directly connects an active element or a detector to a substrate readout face down, eliminating the need for wire bonding. Indium bump technology has been a part of hybridization for many years and has been extensively employed in the infrared imager industry. However, obtaining a reliable, high yield process for high density patterns of bumps can be quite difficult in part due to the tendency of the indium bumps to oxidize during exposure to air. In this study, plasma, thermal, and wet chemical methods were screened to determine their ability to remove indium oxide from indium bumps. A novel two-step plasma process using methane, argon, and hydrogen was developed that removes indium oxide from indium bumps after prolonged air exposure while maintaining a low sample temperature. This method was tested by fabricating a fully hybridized scientific grade visible complementary metal oxide semiconductor detector and imaging a standard test pattern.

Epitaxial growth and characterization of CaVO 3 thin films

Epitaxial thin films of CaVO 3 were synthesized on SrTiO 3, LaAlO 3 and (La 0.27Sr 0.73)(Al 0.65Ta 0.35)O 3 substrates by pulsed laser deposition. All CaVO 3 films, independent of epitaxial strain, exhibit metallic and Pauli paramagnetic behavior as CaVO 3 single crystals. X-ray absorption measurements confirmed the 4+ valence state for Vanadium ions. With prolonged air exposure, an increasing amount of V 3+ is detected and is attributed to oxygen loss in the near surface region of the films.

Creep Data Rationalization for Power Plant Steels

The tensile creep and creep fracture properties at stresses giving creep lives up to 3000 hours are analyzed in relation to data recorded under test conditions producing failure in times up to 100,000 hours at 773 to 923K for multiple batches of 1Cr-1Mo-0.25V steel. Using the θ methodology to quantify the shapes of the short-term creep curves allows accurate prediction of the long-term behavior, avoiding the underestimation of stress rupture performance caused by oxidation of small-diameter specimens during prolonged exposure in air at 823K and above. Moreover, the physically-meaningful θ relationships also introduce techniques for superimposition of the multi-batch results onto 'master curves' through equations which incorporate measurable properties rather than the empirical terms in conventional parametric methods. Even without the sets of high-precision creep curves required to undertake full θ analyses, these rationalization procedures then lead to new approaches for straightforward prediction of long-term design data by extrapolation of short-term creep rate and creep life measurements obtained using standard test facilities.

Physiological responses of pirarucu (Arapaima gigas) to acute handling stress

Pirarucu (Arapaima gigas) is an obligatory air-breathing fish from the Amazon basin. Previous study showed that pirarucu juveniles present a latency period in their response to moderate stress (transportation). Therefore the objective of this study was to verify the effects of a prolonged air exposure stress in lactate, glucose, cortisol, haematocrit, haemoglobin, and liver glycogen in pirarucu. Thirty-six fish were handled by netting and subjected to air exposure for 75-min. Six fish were sampled before handling and at 0, 6, 24, 48, and 96h after handling. Fish cortisol, lactate and haematocrit rose after handling, returning to previous unstressed values on the following sampling (6h after handling). Glucose increased significantly after handling and that was maintained for 24 h. There were no changes in haemoglobin and liver glycogen as a consequence of handling. The results demonstrate a quick response when exposed to an acute stressor and a fast recovery, suggesting that pirarucu does not use their glycogen reserves during an acute stress. The results suggest that pirarucu exhibit physiological stress responses to handling similar in magnitude to those previously documented for many teleostean fishes, including salmonids.

Mn valence instability inLa2∕3Ca1∕3MnO3thin films

A Mn valence instability on ${\mathrm{La}}_{2∕3}{\mathrm{Ca}}_{1∕3}\mathrm{Mn}{\mathrm{O}}_{3}$ thin films, grown on $\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3}$ (001) substrates is observed by x-ray absorption spectroscopy at the Mn $L$-edge and O $K$-edge. As-grown samples, in situ annealed at $800\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ in oxygen, exhibit a Curie temperature well below that of the bulk material. Upon air exposure a reduction of the saturation magnetization, ${M}_{S}$, of the films is detected. Simultaneously a ${\mathrm{Mn}}^{2+}$ spectral signature develops, in addition to the expected ${\mathrm{Mn}}^{3+}$ and ${\mathrm{Mn}}^{4+}$ contributions, which increases with time. The similarity of the spectral results obtained by total electron yield and fluorescence yield spectroscopy indicates that the location of the Mn valence anomalies is not confined to a narrow surface region of the film, but can extend throughout the whole thickness of the sample. High temperature annealing at $1000\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ in air, immediately after growth, improves the magnetic and transport properties of such films towards the bulk values and the ${\mathrm{Mn}}^{2+}$ signature in the spectra does not appear. The Mn valence is then stable even to prolonged air exposure. We propose a mechanism for the ${\mathrm{Mn}}^{2+}$ ions formation and discuss the importance of these observations with respect to previous findings and production of thin films devices.

Yield stress rationalization of creep and creep fracture properties

Abstract For 1Cr–1Mo–0.25V steel, long-term stress-rupture lives are predicted by θ analyses of short-term creep curves, avoiding the effects of oxidation during prolonged creep exposure in air at 773–923 K. These analyses also introduce a new physically-meaningful approach as an alternative to the empirical parametric methods often adopted to represent multi-batch creep and creep fracture data.

A comparative study on the autoxidation of dimethyl ether (DME) comparison with diethyl ether (DEE) and diisopropyl ether (DIPE)

The Japanese government is planning to introduce DME as a substituted energy for oil and LNG. Introduction of DME could contribute greatly to both the prevention of global warming and the formation of resource-recycling societies. In these circumstances, a safety assessment of DME is very important when DME is used on a large scale. There is a possibility that prolonged exposure in air induces autoxidation to produce explosive organic peroxides during transportation and storage of DME. Therefore, the reactivity of DME with oxygen and the mechanism of the autoxidation were investigated. Accelerating Rate Calorimetry (ARC) was used to evaluate the thermal stability of DME and DIPE, a known peroxide producers, under adiabatic and various atmospheric conditions. In ARC studies of DME under oxygen, exothermic decompositions were detected although its self-heating rate was low in comparison with DIPE. Oven storage tests were carried out and iodimetry was used to measure the concentration of peroxides produced from DME in comparison with DIPE and DEE. However, no products could be found for DME either by GC/MS or by iodimetry, while some evidence of autoxidation of both DEE and DIPE were obtained from these experiments.

Oxidation behaviour of Ti–46.7Al–1.9W–0.5Si in air and Ar–20%O 2 between 750 and 950 °C

The oxidation behaviour of an intermetallic alloy, Ti–46.7Al–1.9W–0.5Si, was studied in air and Ar–20%O 2 atmospheres at 750, 850 and 950 °C. Oxidation of the alloy followed a parabolic rate law at low temperature (750 °C) in both environments. The alloy oxidised parabolically in air and at a slower rate in Ar–20%O 2 at 850 °C. Following a parabolic oxidation for a relatively short exposure period (72 h) at 950 °C, the oxidation rate was reduced after prolonged exposure (up to 240 h) in air. The alloy oxidised in a slower manner in the Ar–20%O 2 atmosphere at 950 °C. Higher oxidation rates were observed in air than in Ar–20%O 2 at all three experimental temperatures. Multi-layered scales developed in both environments. The scale formed in air consisted of TiO 2/Al 2O 3/TiO 2/TiN/TiAl 2 layers, ranging from the surface to the substrate—whilst the scale developed in the Ar–20%O 2 atmosphere comprised of the sequence TiO 2/Al 2O 3/TiO 2/Al 2O 3/Ti 3Al/substrate. The two layers of Al 2O 3 in Ar–20%O 2 were more effective in providing protection of the substrate against high temperature corrosion than the single layer of Al 2O 3 formed in air.

Improving the Capacity Retention of LiCoO[sub 2] Cycled to 4.5 V by Heat-Treatment

Impedance growth of LiCoO 2 electrodes cycled with an upper cutoff potential of 4.5 V is caused by side reactions involving species on the surface of LiCoO 2 and LiPF 6 -based electrolyte. These detrimental chemical speciescan apparently be removed by a heat-treatment to 550°C because electrodes made with heat-treated materials show excellent capacity retention even when cycled to 4.5 V. The detrimental surface species can be subsequently reformed on heat-treated materials by exposure of LiCoO 2 to water, suggesting prolonged air exposure is responsible for their formation on commercial samples.