Moderate Elevated Temperature Research Articles

Temperature-dependent responses and trophic interaction strengths of a predatory marine gastropod and rock oyster under ocean warming

Predator-prey interactions are important in shaping ecosystem structure. Consequently, impacts of accelerating global warming on predators will have notable implications. Effects are likely to be particularly marked for tropical organisms which are anticipated to be sensitive to further thermal stress. Here, we investigated effects of future ocean warming on the predatory dogwhelk Reishia clavigera and its predation of Saccostrea cucullata. Mortality of the predators rapidly increased under the extreme elevated temperature, while those exposed to moderate elevated temperature displayed similar mortality as the ambient. Predators that survived moderate temperature increases altered their oxygen consumption patterns, increased average feeding rates, and functional responses, although condition index and energy reserves were unchanged. Overall, we show extreme ocean warming scenarios can remove predators and their consumption of prey from an ecosystem, whereas moderate warming can intensify predator-prey interactions. Such temperature-dependent alterations to predator-prey interactions would lead to fundamental changes of ecosystem structure as the ocean warms.

Degradation of collagen I by activated C1s in periodontal Ehlers-Danlos Syndrome.

Periodontal Ehlers-Danlos syndrome (pEDS) is an autosomal dominant disorder characterized by early-onset periodontitis leading to premature loss of teeth, lack of attached gingiva and thin and fragile gums leading to gingival recession. Connective tissue abnormalities of pEDS typically include easy bruising, pretibial plaques, distal joint hypermobility, hoarse voice, and less commonly manifestations such as organ or vessel rupture. pEDS is caused by heterozygous missense mutations in C1R and C1S genes of the classical complement C1 complex. Previously we showed that pEDS pathogenic variants trigger intracellular activation of C1r and/or C1s, leading to extracellular presence of activated C1s. However, the molecular link relating activated C1r and C1s proteases to the dysregulated connective tissue homeostasis in pEDS is unknown. Using cell- and molecular-biological assays, we identified activated C1s (aC1s) as an enzyme which degrades collagen I in cell culture and in in vitro assays. Matrix collagen turnover in cell culture was assessed using labelled hybridizing peptides, which revealed fast and comprehensive collagen protein remodeling in patient fibroblasts. Furthermore, collagen I was completely degraded by aC1s when assays were performed at 40°C, indicating that even moderate elevated temperature has a tremendous impact on collagen I integrity. This high turnover is expected to interfere with the formation of a stable ECM and result in tissues with loose compaction a hallmark of the EDS phenotype. Our results indicate that pathogenesis in pEDS is not solely mediated by activation of the complement cascade but by inadequate C1s-mediated degradation of matrix proteins, confirming pEDS as a primary connective tissue disorder.

Temperature and solvent facilitated extrusion based 3D printing for pharmaceuticals

On demand manufacturing of patient-specific oral doses provides significant advantages to patients and healthcare staff. Several 3D printing (3DP) technologies have been proposed as a potential digital alternative to conventional manufacturing of oral tablets. For an additive manufacturing approach to be successful for on-demand preparation, a facile process with minimal preparation steps and training requirements is needed. A novel hybrid approach to the 3D printing process is demonstrated here based on combining both a solvent and heating to facilitate extrusion. The system employed a moderate elevated temperature range (65-100 °C), a brief drying period, and a simple set-up. In this approach, a compact material cylinder is used as a pharmaceutical ink to be extruded in a temperature-controlled metal syringe. The process proved compatible with hygroscopic polymers [Poly(vinyl alcohol (PVA) and polyvinylpyrrolidone (PVP)] and a number of pharmaceutical fillers (lactose, sorbitol and D-mannitol). The fabricated tablets demonstrated acceptable compendial weight and content uniformity as well as mechanical resistance. In vitro drug release of theophylline from 3D printed tablets was dependent on the nature of the polymer and its molecular weight. This reported approach offers significant advantages compared to other 3DP technologies: simplification of pre-product, the use of a moderate temperature range, a minimal drying period, and avoiding the use of mechanically complicated machinery. In the future, we envisage the use of this low-cost and facile approach to fabricate small batches of bespoke tablets.

Switching related activation field for polarization-reversal and for polarization-saturation in PVA based NaNO2–CsNO3 mixed system composite films fabricated at moderate elevated temperature

We investigated switching behavior in PVA based NaNO2-CsNO3 mixed system composite films fabricated at moderate elevated temperature. The switching transients in ‘ceramic-polymer mixed system’ exhibiting best ferroelectric response optimized with CsNO3 mole% 0.09 have been analyzed by two different approaches. Following Landauer approach, an activation field is calculated by measuring the rate at which ‘polarization switching’ takes place; it is calculated by measuring average polarization current under the switching transient over the switching time. In second approach, another kind of activation field is calculated by measuring maximum value of polarization current attained in the transient. The calculation of the activation field in the former approach gives the value of minimum field required to take the sample into its saturated state of polarization during the life time of the experiment whereas the one calculated from later approach helps to find the activation field which is just sufficient to initiate the state of polarization reversal.

Responses of young wheat plants to moderate heat stress

Moderate heat stress may provide protection against a subsequent severe high temperature stress in plants. However, the exact mechanisms of heat acclimation of wheat are still poorly understood. In the present work, two wheat varieties Ellvis and Soissons were exposed to a moderate elevated temperature at 30 °C, and the changes of certain protective mechanisms were investigated. Although the differences in the proline level between the genotypes were not substantial, it was approx. 2–3 times higher in the heat-treated plants than in the controls. After exposure to moderate elevated temperature, the activities of ascorbate peroxidase and catalase were also induced. Similarly, the amount of the free salicylic acid also increased after moderate heat stress, independently on the genotypes. The amount of the main polyamines, namely, putrescine, spermidine, and spermine either did not change or decreased after the same period. However, heat acclimation increased the level of 1,3-diaminopropane, in parallel with a polyamine oxidase gene, TaPAO. While the expression level of the peroxisomal polyamine oxidase gene TaperPAO hardly changed, TaPAO showed a substantial increase after 1 day, especially in Soissons, and at the end of the heat treatment was still significantly higher than in the controls. These suggest that signalling processes related to polyamine metabolisms or salicylic acid-related processes might also contribute to the higher heat tolerance induced by moderate heat stress. The variations in recorded measurements were mainly temperature dependent, and the effect of genotype was less pronounced than the effect of moderate heat treatment itself.

Revisiting KAI theory and its application to mixed composite system “–PVA” fabricated at moderate elevated temperature

Ishibashi and Takagi considered ‘ferroelectric domain switching’ just equivalent to ‘phase evolution during crystal growth’. They slightly modified Kolmogorov and Avrami’s classical theory of ‘phase transformations in crystal growth’ and applied it to the switching data in ferroelectrics. Here an effort is made to elucidate mathematical steps in evolution of this new KAI model used to fit experimental switching data to estimate microscopic switching parameters. In mixed composite system (x = 0.09), the domain growth dimension () is found to expand from to when signal amplitude changed from to The cesium substitution is supposed to have enabled lone pairs on central nitrogen of nitrite group to orient constituting branches into more ordered state in the matrix of molecular chains of the PVA facilitating control of crystallization process which led to lowering of strain giving rise to the increased change in with change in pulse amplitude.

Early and efficient induction of antioxidant defense system in Mytilus galloprovincialis embryos exposed to metals and heat stress

The present study aims to elucidate the stress response of early life stages of Mytilus galloprovincialis to the combine effects of selected metals and elevated temperature.For this purpose, we investigated the response of a large panel of oxidative stress markers such as catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST) activities and lipid peroxidation (thiobarbituric acid reactive substrates (TBARS) concentration) and metallothionein accumulation (MT) as well as selected gene transcription level and metal accumulation in mussels larvae exposed to a sub-lethal concentration of Cu (9.54µg/L), Ag (2.55µg/L) and mixture of the two metals (Cu (6.67µg/L)+Ag (1.47µg/L)) along with a temperature gradient (18, 20 and 22°C) for 48h.Cu and Ag applied as single or mixture were differentially accumulated in mussel larvae according to the exposure temperature. Sod, cat, gst and mt-10 gene transcription levels showed an important increase in larvae exposed to Cu, Ag or to the mix compared to the control condition at 18°C. The same pattern but with higher induction levels was recorded in larvae co-exposed to metals at 20°C. At 22°C, a significant decrease in mRNA abundance of cat, gst and sod and a significant up-regulation of mts targets (mt10 and mt20) were observed. Resultssuggest that co-exposure to metals and moderate elevated temperature (20 and 22°C) significantly increased the antioxidant enzyme activities of catalase (CAT), and glutathione-S-transferase (GST) and caused an increase of metal and metallothionein concentrations. In contrast, no significant change in lipid peroxidation products measured as TBARS content was observed indicating a protective response of anti-oxidative system.This study provides first evidences of the early and efficient protective response of antioxidant defense mechanisms in mussel's early life stages facing in multi stressors situations.

Structural Analysis of Enhanced Ferroelectricity in Nano- Composite Films of Sodium Nitrite in poly-Vinyl Alcohol Matrix Fabricated at Moderate Elevated Temperature

Structural Analysis of Enhanced Ferroelectricity in Nano- Composite Films of Sodium Nitrite in poly-Vinyl Alcohol Matrix Fabricated at Moderate Elevated Temperature

High Energy Density Solid-State Lithium Battery

This presentation seeks to present the science and technology of a safe all-solid-state, high-energy density, rechargeable lithium battery. The main breakthroughs in the solid-state battery technology will be summarized and will share our latest contributions in the advancement of the technology. The unit cell of the battery comprises lithium metal as the anode, a novel high performance lithium nickel manganese cobalt oxide based composite cathode and a lithium stable composite electrolyte as separator. At cell level we are able to achieve a very high energy density at moderate rate and elevated temperature. This achievement is made possible by adopting our proprietary composite cathode composition and processing. Another advantage is its ability to operate at high temperature up to 160oC compared to the commercially available lithium-ion batteries, which normally operate only up to 60oC. The targeted applications for the battery are for automobile and others like consumer electronics, power tools, medical, and oil exploration. Key Words: solid composite electrolyte, all-solid-state lithium battery, high-energy density, extended temperature range, and electric vehicles

Impact of long-term moderate hypercapnia and elevated temperature on the energy budget of isolated gills of Atlantic cod (Gadus morhua)

Effects of severe hypercapnia have been extensively studied in marine fishes, while knowledge on the impacts of moderately elevated CO2 levels and their combination with warming is scarce. Here we investigate ion regulation mechanisms and energy budget in gills from Atlantic cod acclimated long-term to elevated PCO2 levels (2500μatm) and temperature (18°C). Isolated perfused gill preparations were established to determine gill thermal plasticity during acute exposures (10–22°C) and in vivo costs of Na+/K+-ATPase activity, protein and RNA synthesis. Maximum enzyme capacities of F1Fo-ATPase, H+-ATPase and Na+/K+-ATPase were measured in vitro in crude gill homogenates. After whole animal acclimation to elevated PCO2 and/or warming, branchial oxygen consumption responded more strongly to acute temperature change. The fractions of gill respiration allocated to protein and RNA synthesis remained unchanged. In gills of fish CO2-exposed at both temperatures, energy turnover associated with Na+/K+-ATPase activity was reduced by 30% below rates of control fish. This contrasted in vitro capacities of Na+/K+-ATPase, which remained unchanged under elevated CO2 at 10°C, and earlier studies which had found a strong upregulation under severe hypercapnia. F1Fo-ATPase capacities increased in hypercapnic gills at both temperatures, whereas Na+/K+ATPase and H+-ATPase capacities only increased in response to elevated CO2 and warming indicating the absence of thermal compensation under CO2. We conclude that in vivo ion regulatory energy demand is lowered under moderately elevated CO2 levels despite the stronger thermal response of total gill respiration and the upregulation of F1Fo-ATPase. This effect is maintained at elevated temperature.

Visual Study of Hollow Cone Water Spray Jet Breakup Process at Elevated Temperatures and Pressures

The liquid jet breakup is a ubiquitous phenomenon in nature and a classic problem in hydrodynamics. The understanding of the jet breakup mechanism of hot liquids is still a challenge for researchers. The objective of this work was to understand and control the hot water spray jet breakup mechanism at moderate pumping pressures and elevated temperature. For this purpose, the visual and comparative studies were conducted on hollow cone water spray patterns generated by three hollow cone spray nozzles which were installed in an in-house built intermittently forced liquid spraying system. Using a high speed camera, the jet breakup dynamics were visualized as a function of system input parameters. The analysis of the grabbed images confirmed the strong influence of these processing parameters on spray characteristics. It was also predicted that heated liquids generate the dispersed spray patterns and the induction of thermal energy into the system enhances the jet disintegration ability. The spray cone width and angle were not varied significantly whereas the Weber and Reynolds numbers along with other spray parameters showed an appreciable response to the load pressure and water heating temperature at early stages of water injection.

Effect of Curing Regimes on Metakaolin Geopolymer Pastes Produced from Geopolymer Powder

The properties of metakaolin geopolymer paste are affected by the alkali concentration, the initial raw materials, solidification process, and amount of mixing water as well as the curing conditions. This study aimed to investigate the effect of curing temperature (room temperature, 40°C, 60°C, 80°C and 100°C) and curing time (6h, 12h, 24h, 48h and 72h) on the geopolymer pastes produced from geopolymer powder. The results showed that curing at room temperature was unfeasible. Heat was required for the geopolymerization process, where strength increased as the curing temperature was increased. Moderate elevated curing temperature favored the strength development of geopolymer pastes in comparison with those treated with extreme elevated curing temperature. When geopolymer paste was subjected to extreme elevated curing temperature, shorter curing time should be used to avoid deterioration in strength gain. Similarly, longer curing time was recommended for moderate elevated curing temperature. The microstructure of geopolymer paste cured at moderate curing temperature showed obvious densification of structure. In contrast, the structure formed was weak and less compact at very high elevated curing temperature.

KUBOTA ALLOY HU

Abstract Kubota Alloy HU is an iron-chromium-nickel alloy with moderate elevated temperature strength and good oxidation resistance. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on casting and joining. Filing Code: SS-1105. Producer or source: Kubota Metal Corporation, Fahramet Division.

An ultrathin Zr(Ge) alloy film as an exhaustion interlayer combined with Cu(Zr) seed layer for the Cu/porous SiOC:H dielectric integration

A highly reliable interface of an ultrathin Zr(Ge) exhaustion interlayer between Cu(Zr) film and porous SiOC:H (p-SiOC:H) dielectric has been developed in the present work. After being processed at a moderate elevated temperature (say, 450 °C), a self-formed nanomultilayer of CuGex/ZrOx(ZrSiyOx) was produced at the interface of Cu(Zr)/p-SiOC:H film stacks, which showed strong ability to effectively hinder Cu atoms diffusion into p-SiOC:H film and free Si atoms diffusion into Cu film. The mechanism involving the thermal stability of the films system is analyzed based on detailed characterization studies.

Model reaction for thermally latent curing through addition of hemiacetal ester and epoxide by schiff‐base–zinc halide complexes

AbstractSchiff‐base–zinc halide complexes (ZnX2/1) thermal‐latently catalyze the reaction of glycidyl phenyl ether (2) and 1‐propoxyethyl 2‐ethylhexanoate (3) that proceeds at moderately elevated temperatures. The catalysis by the ZnX2/1 complexes proceeds via the thermal dissociation of 3 to produce the corresponding carboxylic acid that nucleophilically attacks 2 predominantly over the thermally dissociated vinyl ether. ZnX2/1 complexes catalyze both the dissociation of 3 to produce the carboxylic acid intermediate and its addition to 2. Although conventional latent catalysts for this reaction exhibit Lewis acidities under ambient conditions that are responsible to the gradual degradation of hemiacetal esters and the polymerization of epoxides, a mixture of 2, 3, and ZnX2/1 can be stored for 3 months at ambient conditions. The stored mixture is as active as the freshly prepared mixture, keeping the excellent activity and latency of ZnX2/1. As well as the model reaction, the thermally latent polyaddition of bisphenol A diglycidyl ether (9) and di‐1‐propoxyethyl adipate (10) is also promoted with ZnCl2/1 at a moderate elevated temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3370–3379, 2007

A model for the combined effects of elevated temperature and stress ratio on the LEFM fatigue threshold condition

The effects of moderate elevated temperature and stress ratio on the value of long-crack (LEFM) fatigue threshold stress intensity range ΔK 0 are analysed in the light of a new approach that concentrates on events in a critically stressed material volume V c ahead of the crack tip. A model developed to incorporate the effect of temperature is based on the main concepts of previous models describing the effects of stress ratio, yield strength, and gaseous environment on ΔK 0 at room temperature. The upper- and lower-bound intrinsic thresholds that played important roles in those models are seen to play a similar role in the present model. It is shown that ΔK 0, equalling the upper-bound threshold at room temperature, decreases to a value close to the lower-bound threshold of the material at a characteristic elevated temperature T crit. Good agreement is shown to exist between theoretically predicted and experimental ΔK 0 vs R and ΔK 0 vs temperature curves for several low-strength steels tested in the laboratory air environment. The model may be useful in obtaining a quick, fairly accurate and conservative estimate of ΔK 0 for material selection and design.