Long-term Oxide Research Articles

Phase thermal stability and low thermal stress in MgO–BaO–CaO–Al2O3–B2O3–SiO2 glass-ceramic for long-term solid oxide fuel cells

The crystallization thermal stability plays an essential role in affecting thermal stress of glass-ceramic sealant for long-term planar-type solid oxide fuel cells (SOFC) to prevent fuel leakage during operation. Due to the lack of systematic research on regulating the stable performance of glass-based sealant with the working time at operation temperature, herein, the effect of MgO on crystallization kinetics, phase stability, and thermal and mechanical properties of MgO–BaO–CaO–Al2O3–B2O3–SiO2 (MBCABS) glass-ceramic has been firstly analyzed at heat-treatment of 750 °C with working time of 1∼1000h in this work. Subsequently, the relationship evolution of crystallization thermal stability-coefficient of thermal expansion (CTE) match-thermal stress was established by Finite Element Method (FEM). The main reasons for the decrease of CTE of MBCABS glass-ceramics with low-content MgO are the precipitation of hexagonal BaAl2Si2O8 phase and the transformation of hexagonal BaAl2Si2O8 to low-CTE monoclinic BaAl2Si2O8 phase, bring about that the Von Mises thermal stress of sealant itself and interface having tripled at 1000h (more than 200 MPa) according to FEM simulation results. The thermal stable and high-CTE BaMgSiO4, Ba8Mg16Si16O56, and BaCa2Mg(SiO4)2 phases crystallized in MBCABS glass-ceramics with high-content MgO, therefore the maximum stress at all time parameters was below 100 MPa for 1∼1000h. This study was useful for identifying the optimal phase option and CTE matching of glass-based sealant for efficient and stable long-term operation of solid oxide fuel cells.

Ni/GDC Fuel Electrode for Low-Temperature SOFC and its Aging Behavior Under Accelerated Stress

The microstructural integrity of Ni-based fuel electrodes is important for long-term solid oxide fuel cell (SOFC) operation. Degradation due to microstructural changes such as Ni-agglomeration, coarsening, and densification must be prevented by an appropriate microstructure. Here, the performance of four types of nickel-ceria-based fuel electrodes, which differ concerning layer sequence and manufacturing processes, was evaluated by electrochemical impedance spectroscopy at the nominal operating temperature of 600 °C. Electrodes produced through screen-printed GDC exhibited an acceptable polarization resistance (0.260 Ωcm2), whereas electrodes with an additional printed Ni/GDC layer demonstrated inferior performance (0.550 Ωcm2). Electrodes formed through infiltration of GDC into the printed GDC-layer displayed unreproducible performance values ranging from 0.16 to 1.20 Ωcm2 despite similar processing. Conversely, electrodes with an extra layer of GDC infiltrated into the Ni-backbone exhibited good performance (0.195 Ωcm2) and stability. Accelerated degradation tests under OCV at increased operating temperatures of 700 and 900 °C were performed on the sample based on a GDC infiltrated Ni-backbone that performed best among reproducible samples. The polarization resistance at 600 °C recorded at the beginning and the end of life increased by up to 100%. Microstructural analysis of the electrodes at different aging states revealed strong microstructural changes of fine-infiltrated GDC structures and Ni agglomeration at higher operating temperature.

Chronic Inhibition of Nitric Oxide Synthases Impairs Spatiotemporal Learning and Memory to a Similar Extent in C57BL/6 and hAPP23+/− Mice

Due to global population growth, age-related disorders like cardiovascular disease and dementia are anticipated to increase. Recent data suggests a connection between cardiovascular disease and neurodegeneration, especially focusing on arterial stiffness (AS) and Alzheimer’s disease (AD). In light of this, we conducted a study to explore the impact of long-term nitric oxide synthase (NOS) isoform inhibition, which leads to AS, on neurobehavioral performance. We also compared these effects in an AD model and control mice. C57BL/6 and hAPP23+/− mice (an established AD model) were given 0.5 mg/mL N(G)-Nitro-L-Arginine Methyl Ester (L-NAME) in their drinking water for 16 weeks. Our findings indicate that chronic non-selective NOS inhibition increased AS and reduced spatiotemporal learning and memory in both C57BL/6 and hAPP23+/− mice. These effects were consistent across both groups, emphasizing the role of neuronal NOS (nNOS) in cognitive aging, regardless of genetic predisposition to AD.

Long-term pulmonary iron oxide nanoparticles exposure disrupts hepatic iron-lipid homeostasis and increases plaque vulnerability in ApoE−/− mice

Iron oxide nanoparticles (Fe3O4 NPs) have attracted great attention due to their extensive applications, which warranted their environmental concerns. Although recent advances have proposed the relevance of Fe3O4 NPs to cardiovascular disease, the intrinsic mechanisms underlying the effects of NPs remain indistinct. ApoE−/− mice were chosen as a long-term exposure model to explore the immanent association between respiratory exposure to Fe3O4 NPs and the development of cardiovascular diseases. Pulmonary exposure to 20 nm and 200 nm Fe3O4 NPS resulted in significant lung injury, and pulmonary histopathological examination displayed inflammatory cell infiltration, septal thickening and alveolar congestion. Intriguingly, liver iron deposition and variations in the hepatic lipid homeostasis were found in Fe3O4 NPs-exposed mice, eventually leading to dyslipidemia, hinting the potential cardiovascular toxicity of Fe3O4 NPs. In addition, we not only found that Fe3O4 NPs exposure increased aortic plaque area, but also increased M1 macrophages in the plaque, which yielding plaque vulnerability in ApoE−/− mice Of note, 20 nm Fe3O4 NPs showed enhanced capability on the progression of atherosclerosis than 200 nm Fe3O4 NPs. This study may propose the potential mechanism for adverse cardiovascular disease induced by Fe3O4 NPs and provide convincing evidence for the safety evaluation of Fe3O4 NPs.

Enabling long-term oxide based solid-state lithium metal battery through a near room-temperature sintering process

The huge Li ion transport resistance through the grain boundaries (GBs) among rigid oxide particles forces the adoption of high-temperature sintering (HTS) process over 1000 °C. Nevertheless, the severe side reactions and uncontrollable lithium loss are always companied during the high-cost HTS process, which slows down the pace of oxide solid electrolyte (OSE) for practical application and accelerates the exploration of a new OSE sintering process. Herein, a near-room-temperature (60 °C) cold-sintering process is proposed by filling the GBs with a low-melting-point plastic crystal electrolyte (PCE). Due to the soft property and high-ionic conductivity of PCE, the Li ion transport rate through the GBs is 10 times faster than the bulk phase, endowing the OSE (Li1.5Al0.5Ge1.5(PO4)3 chosen as a representative) with a room temperature ionic conductivity of 0.25 mS cm−1. As proof of the concept, the assembled Li symmetrical cells perform a low over-potential of 50 mV with a capacity of 1 mA h cm−2 and full cells delivers a capacity retention of roughly 70% after 820 cycles (1.5 years) at 0.1C.

Optimization of Extrinsic Impact Factors for Improving Performance and Mitigating Performance Degradation of LSCF-SDC/YSZ/Ni-YSZ Cells Under Solid Oxide Electrolysis Operation

Long-term solid oxide electrolysis operation (SOEC) testing was performed to study the performance and performance degradation of LSCF-SDC/YSZ/Ni-YSZ cells under temperatures of 750 oC, 800 oC, and 850 oC, current density of 0.5A/cm2 and 1.0A/cm2, and H2/H2O ratio of 1:1, 1:3, and 2:1. Operational temperature, current density, and H2/H2O ratio played important roles in the cells’ performance and performance degradation. These factors were correlated and should be balanced and/or optimized to maximize overall lifetime performance. LSCF-SDC cells showed better performance and less performance degradation under higher temperature. Electrochemical impedance spectroscopy (EIS) data showed polarization resistance was significantly lower for the cell operated at higher temperature. Therefore, SOEC operation may need relatively higher temperature to be activated. Long-term SOEC testing under different current density showed better performance and less performance degradation at 0.5A/cm2, 850 oC, and 1:1 of H2/H2O ratio. H2/H2O ratio in the functional layer of the cell also played an important role. The cell showed best performance and less performance degradation under 1:1 of H2/H2O ratio. EIS data showed the polarization resistance was significantly lower under 1:1 of H2/H2O ratio. H2/H2O ratio needs to be optimized for different operational temperature and current density. Overdosed steam may react with Ni causing Ni movement in the H2 electrode, adding to cell degradation. Transmission electron microscopy (TEM) studies identified the formation of the (CoFe)Ox along the SDC grain boundaries, which could impact both the SDC conductivity and the LSCF catalytic activity due to the loss of the transition metals in the LSCF. TEM analysis of the H2 electrode identified a large number of NiO clusters relocated into the original pore region, seemingly formed during Ni migration. This NiO formation in the H2 electrode during SOEC operation is another cause of long-term performance degradation.

Improving long-term solid oxide fuel cell stack performance prediction accuracy using a microstructure evolution model

Solid oxide fuel cells (SOFCs) are highly efficient energy conversion devices capable of utilizing a wide range of fuels. However, a variety of degradation phenomena affects their long-term performance and durability. The purpose of this study is to explain an increase in voltage of an SOFC stack observed during a 3800 h-long period of operation. A three-dimensional phase field model using focused ion beam scanning electron microscopy data as initial input is used to simulate the evolution of an SOFC microstructure over a period of prolonged operation. For the generated time steps, microstructure parameters are obtained, and a microstructure-scale mass and charge transport model is used to predict the voltage change. The microstructure evolution model, combined with the electrochemical performance model, predicts the 0.01 V increase in terminal voltage during the 3800-long period of operation, which is consistent with the experimental results. The behavior is predicted for various phase mobility ratios, suggesting that the phenomenon is related to the specific characteristics of the particular microstructure investigated in the study. Clearing of diffusion pathways is identified as the root cause of the performance enhancement. Additionally, the results suggest non-negligible changes in the ceramic phase within the electrode.

Thallium isotope cycling between waters, particles, and sediments across a redox gradient

Thallium (Tl) isotopes are an emerging tool for tracking the history of molecular oxygen in seawater. Use of Tl isotopes in this manner requires a thorough understanding of the modern Tl isotope cycle, especially within the anoxic settings that typified Earth’s past oceans. To this end, we generated Tl concentration and isotope data for waters, particles, and sediments collected during three spring-summer-fall field seasons in Siders Pond, a salt-stratified and sulfide-rich (‘euxinic’) pond on Cape Cod (Massachusetts, USA). Over short timeframes (i.e., days to weeks), we observed a large degree of variability in the abundance (Tldiss = 9 pM–42 pM) and isotopic composition (ε205Tldiss = –3.9 ± 0.4; 2SD to –0.1 ± 0.7; 2SD) of dissolved Tl in pond surface waters. Thallium drawdown was common and favored removal of the lighter-mass Tl isotope. We surmise that biological Tl uptake plays a role in this phenomenon, but more work is warranted to confirm this hypothesis. Manganese oxides persisted in pond surface waters on many sampling days but had no obvious effect on Tldiss, only a slight effect on particulate ε205Tl values on the day of most prolific Mn oxide accumulation (driving ε205Tlpart as high as +0.9 ± 0.8; 2SD). In euxinic waters below the oxycline, rapid drawdown of dissolved Tl was observed on all sampling days together with a complimentary increase in particulate Tl (up to Tlpart = 21 pM). Strong associations between Tl and sulfide, and between Tl and other chalcophile metals (Mo and Cd), suggest that Tl is probably removed from euxinic waters in association with particulate sulfides, and seemingly with no resolvable isotopic fractionation effect despite non-quantitative Tl removal. The sediment data track the longer-term Tl cycle in the pond (i.e., across years) and reveal limited isotopic variability. Thallium isotope compositions leached from surface sediments match those predicted for contemporaneous waters, or nearly so, at all depths in the pond (above, within, and below the oxycline). Apparently, only a small fraction of the short-term Tl isotope variability found in the oxic surface waters of Siders Pond gets transferred to anoxic waters, and essentially none is transferred to sediments. Our results reaffirm the notion that Tl isotopes are uniquely capable of tracking long-term sedimentary Mn oxide burial – not mere Mn oxide formation. Our results also verify the ability of sediments formed under reducing conditions to capture the Tl isotope composition of contemporaneous waters. More broadly, the results of our investigation bolster our knowledge of the modern Tl isotope cycle and thereby permit more confident inferences of this cycle in Earth’s past.

Generation of Stable Photovoltage in Nonstoichiometric CuBi2O4 Thin-Film Photocathodes

We investigated the effects of stoichiometry on photovoltages and photocurrents in CuBi2O4 thin-film photocathodes grown by pulsed laser deposition under different oxygen partial pressures to manipulate their stoichiometry. While the X-ray diffraction patterns show crystalline phases in the CuBi2O4 thin films, it is found that the Cu/Bi ratio of the CuBi2O4 thin films varied from ~0.3 to ~0.5 which are analyzed by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. The slightly off-stoichiometric CuBi2O4 thin-film photocathode with a Cu/Bi ratio of ~0.44 shows the highest photocurrent density in the CuBi2O4 thin films. More interestingly, the off-stoichiometric CuBi2O4 thin-film photocathode with a Cu/Bi ratio of ~0.44 exhibited a stable open-circuit voltage difference of ~0.2 V RHE without severe degradation over time. On the other hand, the photovoltage of the stoichiometric CuBi2O4 thin-film photocathode with a Cu/Bi ratio of ~0.5 gradually decreased as a function of time. Our results suggest that stoichiometry manipulation can be one of the promising strategies to achieve long-term stable Cu-based oxide photocathodes with the maintenance of a stable photovoltage.

Effects of Long-Term Dietary Zinc Oxide Nanoparticle on Liver Function, Deposition, and Absorption of Trace Minerals in Intrauterine Growth Retardation Pigs.

To investigate the long-term effects of dietary zinc oxide nanoparticle (Nano-ZnO, 20-40 nm) on the relative organ weight, liver function, deposition, and absorption of trace minerals in intrauterine growth retardation (IUGR) pigs, piglets were allocated to NBW (6 normal birth weight piglets fed basal diets), IUGR (6 IUGR piglets fed basal diets) and IUGR+NZ (6 IUGR piglets fed basal diets + 600 mg Zn/kg from Nano-ZnO) groups at weaning (21 days of age), which were sampled at 163 days of age. There were no noteworthy changes in the relative weight of organs, hepatic histomorphology, serum alkaline phosphatase, glutamic pyruvic transaminase and glutamic oxalacetic transaminase activities, and Mn, Cu, and Fe concentrations in leg muscle, the liver, the tibia, and feces among the IUGR, NBW, and IUGR+NZ groups (P>0.05), and no intact Nano-ZnO in the jejunum, liver, and muscle was observed, while dietary Nano-ZnO increased the Zn concentrations in the tibia, the liver, serum, and feces (P<0.05) and mRNA expression of metallothionein (MT) 1A, MT2A, solute carrier family 39 member (ZIP) 4, ZIP14, ZIP8, divalent metal transporter 1, solute carrier family 30 member (ZnT) 1, ZnT4 and metal regulatory transcription factor 1, and ZIP8 protein expression in jejunal mucosa (P<0.05). Immunohistochemistry showed that dietary Nano-ZnO increased the relative optical density of ZIP8 (mainly expressed in cells of brush border) and MT2A (mainly expressed in villus lamina propria and gland/crypt) (P<0.05). In conclusion, long-term dietary Nano-ZnO showed no obvious side effects on the development of the major organs, liver function, and metabolism of Cu, Fe, and Mn in IUGR pigs, while it increased the Zn absorption and deposition via enhancing the expression of transporters (MT, ZIP, and ZnT families) in the jejunum, rather than via endocytosis as the form of intact nanoparticles.

Origin for retained activity in Pr2NiO4 while undergoing substantial phase transformation in a long-term solid oxide cell operation

Pr2NiO4 (PNO) is a known active oxygen electrode for solid oxide cells but undergoes phase transformation at high temperatures. An in-situ synchrotron study on PNO electrodes show that phase transformation reaches nearly 100% in a long-term operation. Such significant phase transformation is expected to play a detrimental role on the cell performance. However, PNO retains the activity in an enduring operation. The origin for this dichotomy has remained obscure. The aim of this article is to investigate the origin for retained activity and performance stability in PNO electrode. High-resolution transmission electron microcopy analysis shows the presence of a large number of nanoclusters (∼ 5 nm) through the entire electrode bulk, which are localized in the 20–60 nm region. In-situ synchrotron studies show that those nanoclusters are nickelates that account for the retained activity during phase transformation.

Steam Electrolysis vs. Co-Electrolysis: Mechanistic Studies of Long-Term Solid Oxide Electrolysis Cells

High-temperature electrolysis using solid oxide electrolysis cells (SOECs) is an innovative technology to temporarily store unused electrical energy from renewable energy sources. However, they show continuous performance loss during long-term operation, which is the main issue preventing their widespread use. In this work, we have performed the long-term stability tests up to 1000 h under steam and co-electrolysis conditions using commercial NiO-YSZ/YSZ/GDC/LSC single cells in order to understand the degradation process. The electrolysis tests were carried out at different temperatures and fuel gas compositions. Intermittent AC- and DC- measurements were performed to characterize the single cells and to determine the responsible electrode processes for the degradation during long-term operation. An increased degradation rate is observed at 800 °C compared to 750 °C under steam electrolysis conditions. Moreover, a lower degradation rate is noticed under co-electrolysis operation in comparison to steam electrolysis operation. Finally, the post-test analyses using SEM-EDX and XRD were carried out in order to understand the degradation mechanism. The delamination of LSC is observed under steam electrolysis conditions at 800 °C, however, such delamination is not observed during co-electrolysis operation. In addition, Ni-depletion and agglomeration are observed on the fuel electrode side for all the cells.

A Systematic Study of the Role of Cathodic Polarization and New Findings on the Soft Sparking Phenomenon from Plasma Electrolytic Oxidation of an Al-Cu-Li Alloy

Understanding the role of cathodic polarization and soft sparking is critical for plasma electrolytic oxidation (PEO). In this study, PEO of an Al-Cu-Li alloy has been carried out under cathodic to anodic current density ratio (R) from 0 to 3.3. Controlled potential tests and electrochemical impedance microscopy are also adopted. The results show that increased cathodic polarization improves the long-term oxide growth efficiency until an optimum soft sparking regime is reached at R = 1.2, after that the efficiency decreases and damages to the coatings occur. Interestingly, anodic potential drop, which was considered one of the characteristics of soft sparking, is absent in some cases under R = 1.2, and the coatings under R = 1.2 is also featured by a white outer layer enriched with cations. Excessive cathodic polarization (R = ∼2.0–3.3) leads to the compact coatings with highest impedance values at the early PEO stage (300 s), but they deteriorated rapidly. The complex PEO behaviors with different cathodic polarization has been explained in terms of the intercalation of hydrogen species, mass transportation affected by H2 evolution, charge extraction and hydrogen induced stresses. Reciprocally, controlled potential tests indicate that anodic polarization also suppresses the subsequent cathodic hydrogen evolution.

Degradation Analysis of Long-Term Solid Oxide Fuel Cell Stacks with Respect to Chromium Poisoning in La0.58Sr0.4Co0.2Fe0.8O3−δ and La0.6Sr0.4CoO3−δ Cathodes

Chromium poisoning as a result of Cr evaporation from the metallic components and the subsequent deposition on the cathode (i.e., air) side is one of the most critical degradation mechanisms in solid oxide fuel cell (SOFC) stacks. Recently, the LSC cathode (i.e., La0.6Sr0.4CoO3−δ ) exhibited more promising results in both fuel cell and electrolysis modes than the LSCF (i.e., La0.58Sr0.4Co0.2Fe0.8O3−δ ) due to its higher ionic conductivity, despite a relatively high thermal expansion coefficient (TEC). Furthermore, it has been reported that the oxygen surface exchange kinetics and Sr stability/activity in LSC may imply higher resistance against Cr poisoning in comparison to LSCF. For these reasons, long−term stack operation with both LSCF and LSC cathodes was performed for two different stack designs. The degradation behavior of the stacks with respect to Cr poisoning was analyzed with the support of electrochemical impedance spectroscopy and post-mortem analysis.

Degradation Analysis of Long-Term Solid Oxide Fuel Cell Stacks with Respect to Chromium Poisoning in La0.58Sr0.4Co0.2Fe0.8O3-δ and La0.6Sr0.4CoO3-δ Cathodes

Chromia-forming steels or chromium containing alloys are widely used in solid oxide fuel cell (SOFC) stacks and systems. Chromium poisoning as a result of Cr evaporation from the metallic components and thereafter the deposition at cathode side (i.e. air side) is one of the most critical degradation mechanisms in SOFCs. Although the chromium poisoning mechanisms have been studied intensively in the last decades worldwide, there are still debates and contradictory results on different aspects of the mechanism. Despite of these debates, degradation due to chromium poisoning has been reduced largely through optimized protective coatings on the interconnector and improvement of cathode materials. Previous long-term stack tests at the Forschungszentrum Jülich have shown that a reproducible low degradation rate of less than 0.3 %kh-1 can be obtained with the state-of-the-art plasma-sprayed MCF coating (i.e., MnCo1.9Fe0.1O3-δ) and LSCF cathode (i.e., La0.58Sr0.4Co0.2Fe0.8O3-δ) when operating at 700 °C~750 °C with hydrogen and compressed air under a current density of 0.5 A·cm-2 and fuel utilization of 40%. Recently, the LSC cathode (i.e., La0.6Sr0.4CoO3-δ) has shown more promising results in both fuel cell and electrolysis modes than LSCF due to its higher ionic conductivity, despite of a relatively larger thermal expansion coefficient (TEC). Furthermore, it has been reported by other research groups that the oxygen surface exchange kinetics and Sr stability/activity of LSC may suggest a higher resistance against Cr poisoning, compared to LSCF. For these reasons, long-term stack operation with both LSCF and LSC cathodes were performed in two different stack designs (i.e., robust F-design and lightweight cassette design). The degradation behaviour of the stacks with respect to Cr poisoning was analysed with the support of electrochemical impedance spectroscopy and post-mortem analysis (e.g., microanalysis using scanning electron microscopy and chemical analysis using inductively coupled plasma – optical emission spectroscopy). In this work, the results of more than four stacks with an operating time between 5,000 h and 10,000 h will be presented.

Degradation Analysis of Long-Term Solid Oxide Fuel Cell Stacks with Respect to Chromium Poisoning in La0.58Sr0.4Co0.2Fe0.8O3-δ and La0.6Sr0.4CoO3-δ Cathodes

Chromium poisoning as a result of Cr evaporation from the metallic components and the subsequent deposition on the cathode (i.e., air) side is one of the most critical degradation mechanisms in solid oxide fuel cell (SOFC) stacks. Recently, the LSC cathode (i.e., La0.6Sr0.4CoO3-δ) exhibited more promising results in both fuel cell and electrolysis modes than the LSCF (i.e., La0.58Sr0.4Co0.2Fe0.8O3-δ) due to its higher ionic conductivity, despite a relatively larger thermal expansion coefficient (TEC). Furthermore, it has been reported that the oxygen surface exchange kinetics and Sr stability/activity of LSC may imply higher resistance against Cr poisoning by comparison to LSCF. For these reasons, long-term stack operation with both LSCF and LSC cathodes was performed for two different stack designs. The degradation behavior of the stacks with respect to Cr poisoning was analyzed with the support of electrochemical impedance spectroscopy and post-mortem analysis.

Earthworms did not increase long-term nitrous oxide fluxes in perennial forage and riparian buffer ecosystems

Many laboratory and mesocosm studies have demonstrated that earthworms influence nitrogen (N) cycling reactions and produce nitrous oxide (N2O) in well-aerated soils, but whether earthworms can stimulate N2O fluxes in realistic field conditions remains to be determined. We conducted two field experiments, in perennial forage agroecosystems for 2 yr and agriculture riparian buffers for 1 yr, to compare N2O fluxes from enclosures with ambient and artificially elevated earthworm populations. Despite a short-term (< 3 month) increase in mean N2O fluxes from the perennial forage enclosures with artificially elevated earthworm populations, this effect disappeared within 1 yr, with no significant difference (p> 0.05) in mean N2O flux from enclosures in either field experiment. The elevated earthworm populations declined and stabilized at the same level as the ambient earthworm populations within 1–2 yr after the field experiments began. The homeostatic regulation of earthworm populations under field conditions could be due to inter- and intra-specific competition, related to limitation in the food supply and habitat preferred by earthworms. Mean N2O fluxes in the perennial forage fields were negatively correlated with soil moisture, but not related to earthworm populations. In the riparian buffers, the average N2O flux was negatively correlated with vegetation cover, and positively correlated with soil moisture and the size of the earthworm population at the end of the study. Our results suggest that the effects of earthworm addition on N2O emissions in laboratory studies can not necessarily be extrapolated to field settings. Earthworm field experiments that continue in the longer-term and in a variety of ecosystems should improve our understanding of the seasonal and environmental variability in earthworm activity and N2O production under field conditions.

A Mathematical Model for Prediction of Long-Term Degradation Effects in Solid Oxide Fuel Cells

A mathematical model of long-term solid oxide fuel cell (SOFC) degradation is proposed based on a cross-cutting meta-study of SOFC degradation research available in the open literature. This model ...

A Study on the Safety of Long-Term Magnesium Oxide Administration in Elderly Patients with Impaired Renal Function

A Study on the Safety of Long-Term Magnesium Oxide Administration in Elderly Patients with Impaired Renal Function

Molecular investigation of hormonal alterations in Oreochromis niloticus as a bio-marker for long-term exposure to zinc oxide nanoparticles

This study aimed to investigate the potential effects of long-term zinc oxide nanoparticles’ (Zn-ONPs) exposure to the hormonal profile of O. niloticus and their application as a bio-marker for fresh water pollution by Zn-ONPs. Two hundred-forty female O. niloticus were used. Growth hormone (GH), thyroid stimulating hormone (TSH), triiodothyronine (T3), tetraiodothyronine (T4), follicular stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), glucagon, insulin, Adrenocorticosteroid hormone (ACTH) serum concentrations and the expression levels of GH, insulin-like growth factor gene (IGF-I), insulin and insulin receptor A (IRA) genes were determined. The levels of GH, TSH, FSH, LH, T3, T4, Estradiol, E2, insulin and GH, IGF-I, insulin and IRA genes expression decreased significantly in Zn-ONPs’ exposed fish in a concentration-dependent manner; meanwhile, serum ACTH and cortisol increased. The alterations in hormone levels and their gene expressions are considered as good bio-markers for the detection of fresh water pollution with Zn-ONPs.