AC Activity Research Articles

Analysis on Dielectric, Thermal, and Mechanical Characteristics of Nickel Boro Phthalate NLO Crystal for Optoelectronic Applications

AbstractDielectric, thermal, and mechanical behavior of an efficient nonlinear crystal, nickel boro phthalate (NBP), grown by a slow evaporation solution growth technique, is characterized for optoelectronic applications. Ultraviolet absorption study identifies the lower cutoff wavelength as 281 nm. This low value along with transparency in the visible and infrared regions establishes that NBP is a probable nonlinear material. The frequency and the temperature dependency of dielectric constant and dielectric loss are probed. AC conductivity and activation energy are computed, to examine the semiconducting ability of the crystal. Thermal gravimetric analysis and differential thermal analysis are carried out to determine the decomposition temperature. Mechanical characterization is performed by the Vickers microhardness test. The study reveals that NBP comes under the category of soft material. Mechanical properties such as the elastic stiffness constant, brittleness index, yield strength, and fracture toughness are explored.

A study on electrical (dc/ac) conductivity and dielectric characteristics of quaternary Ge50In4Ga13Se33 chalcogenide thin films

Thermally evaporated Ge50In4Ga13Se33 thin films of different thicknesses (126–745 nm) within the frequency range (100 Hz–1 MHz) and in the temperature range (293–413 K) had been studied to investigate the dc electrical conductivity σdc, temperature and frequency dependence of ac conductivity σac(ω) and dielectric parameters. It turned out that dc electrical conductivity σdc is thermally activated over the entire temperature range and the value of ΔEσ was independent of the film thickness and nearly equal the half value of optical energy gapEgopt. The ac conductivity σac(ω) was found to be temperature and frequency dependent. Values of the ac activation energy ΔEσ(ω) were calculated and decreased with the applied frequency. The ωs law was found to be applicable with the results and the frequency exponent s has a positive value ≤1. The obtained values of s were decreased with temperature and interpreted in terms of the correlated barrier hopping (CBH) model. Values of the maximum height of the barrier WM and the density of localized states at the Fermi level N(EF) were calculated. The real ε′(ω) and imaginary ε″(ω) parts of dielectric constant were studied as a function of frequency and temperature.

Dynamics of adrenergic signaling in cardiac myocytes and implications for pharmacological treatment

Dense innervation of the heart by the sympathetic nervous system (SNS) allows cardiac output to respond appropriately to the needs of the body under varying conditions, but occasionally the abrupt onset of SNS activity can trigger cardiac arrhythmias. Sympathetic activity leads to the release of norepinephrine (NE) onto cardiomyocytes, activating β1-adrenergic receptors (β1-ARs) and leading to the production of the second messenger cyclic AMP (cAMP). Upon sudden activation of β1-ARs in experiments, intracellular cAMP can transiently rise to a high concentration before converging to a steady state level. Although changes to cellular cAMP concentration are important in modulating the overall cardiovascular response to sympathetic tone, the underlying mechanisms of the cAMP transients and the parameters that control their magnitude are unclear.We reduce a detailed computational model of the β1-adrenergic signaling cascade to a system of two differential equations by eliminating extraneous variables and applying quasi-steady state approximation. The structure of the reduced model reveals that the large cAMP transients associated with abrupt β1-AR activation are generated by the interplay of production/degradation of cAMP and desensitization/resensitization of β1-ARs. The reduced model is used to predict how the dynamics of intracellular cAMP depend on the concentrations of norepinephrine (NE), phosphodiesterases 3 and 4 (PDE3,4), G-protein coupled receptor kinase 2 (GRK2), and β1-AR, in healthy conditions and a simple model of early stages of heart failure.The key findings of the study are as follows: 1) Applying a reduced model of the dynamics of cardiac sympathetic signaling we show that the concentrations of two variables, cAMP and non-desensitized β1-AR, capture the overall dynamics of sympathetic signaling; 2) The key factors influencing cAMP production are AC activity and PDE3,4 activity, while those that directly impact β1-AR phosphorylation are GRK2 and PKA1. Thus, disease states that affect sympathetic control of the heart can be thoroughly assessed by studying AC activity, PDE3,4, GRK2 and PKA activity, as these factors directly impact cAMP production/degradation and β1-AR (de) phosphorylation and are therefore predicted to comprise the most effective pharmaceutical targets in diseases affecting cardiac β1-adrenergic signaling.

Mutations in tomato 1-aminocyclopropane carboxylic acid synthase2 uncover its role in development beside fruit ripening.

The role of ethylene in plant development is mostly inferred from its exogenous application. The usage of mutants affecting ethylene biosynthesis proffers a better alternative to decipher its role. In tomato (Solanum lycopersicum), 1-aminocyclopropane carboxylic acid synthase2 (ACS2) is a key enzyme regulating ripening-specific ethylene biosynthesis. We characterised two contrasting acs2 mutants; acs2-1 overproduces ethylene, has higher ACS activity, and has increased protein levels, while acs2-2 is an ethylene underproducer, displays lower ACS activity, and has lower protein levels than wild type. Consistent with high/low ethylene emission, the mutants show opposite phenotypes, physiological responses, and metabolomic profiles compared with the wild type. The acs2-1 mutant shows early seed germination, faster leaf senescence, and accelerated fruit ripening. Conversely, acs2-2 has delayed seed germination, slower leaf senescence, and prolonged fruit ripening. The phytohormone profiles of mutants were mostly opposite in the leaves and fruits. The faster/slower senescence of acs2-1/acs2-2 leaves correlated with the endogenous ethylene/zeatin ratio. The genetic analysis showed that the metabolite profiles of respective mutants co-segregated with the homozygous mutant progeny. Our results uncover that besides ripening, ACS2 participates in the vegetative and reproductive development of tomato. The distinct influence of ethylene on phytohormone profiles indicates the intertwining of ethylene action with other phytohormones in regulating plant development.

Effect of short time ball milling on physicochemical and adsorption performance of activated carbon prepared from mangosteen peel waste

This study investigates the short time ball milling effect on surface properties of activated carbon.(AC) produced from mangosteen peels (MP) waste and its subsequent effects on adsorption of cationic methylene blue (MB) from aqueous solution. AC was synthesized from MP waste under mild experimental conditions and was ball milled for a short time (30 min–120 min) at 350 rpm. The physicochemical properties of ball milled AC (BMAC) were investigated using BET, FTIR, TGA, FESEM, XRD and particle size distribution analysis. Various experimental results revealed that MB adsorption on BMAC was greatly influenced by basic pH, contact time and high temperature. The adsorption capability of BMAC was found to increase with decreasing particle size with ball milling. Kinetics study revealed that the adsorption capability of BMAC was best represented by pseudo second order kinetic model and adsorption equilibrium was well described by Langmuir isotherm. The adsorption process was endothermic and spontaneous as revealed by thermodynamic study. Overall, this work demonstrated that ball milling decreases the particle size of AC, increased its efficiency for adsorption of dye, and opened new ways for activation of AC using the ball-milling technique.

Effect of AgI doping on electrical conductivity and dielectric relaxation in silver phosphate glass nanocomposite systems

A series of ternary silver iodide (AgI)-doped glassy samples of xAgI–(1-x)(0.35P2O5–0.65Ag2O) composition with x = 0.1, 0.2, 0.3 and 0.4 have been processed by well-accepted melt quench technique. The composition-dependent thermal properties of the glassy systems have been analyzed by differential scanning calorimetric (DSC) results. Both density and thermal stability of the nanocomposites increases with the inclusion of AgI content (x). The diminishing nature of ac and dc activation energy enhances ac and dc conductivity with rising AgI content (x). The falling response of the inter-nuclear spacing of Ag+ ion (RAg) is responsible for the enhancement of ionic conductivity. The dielectric constant (ε/) and dielectric loss (ε//) values expand with increasing temperature and reduce with rising frequency. The scaled spectra of complex electric modulus (M/ and M//) indicate that conductivity or dielectric relaxation mechanism is not Debye type, as β < 1 and temperature independent, whereas composition dependent.

Crystal structure and enzymatic characterization of the putative adenylyl cyclase HpAC1 from Hippeastrum reveal dominant triphosphatase activity

HpAC1, a protein from Hippeastrum hybrid cultivars, was previously suggested to be a plant adenylyl cyclase. We describe a structural and enzymatic characterization of HpAC1. A crystal structure of HpAC1 in complex with a non-hydrolyzable GTP analog confirms a generic CYTH architecture, comprising a β-barrel with an internal substrate site. The structure reveals significant active site differences to AC proteins with CYTH fold, however, and we find that HpAC1 lacks measurable AC activity. Instead, HpAC1 has substantial triphosphatase activity, indicating this protective activity or a related activity as the protein’s physiological function.

Dielectric relaxation behavior and overlapping large polaron tunneling conduction mechanism in NiO–PbO μ-cauliflower composites

The NiO–PbO μ-cauliflower composites was synthesized via glycine assisted self-ignition techniques with an objective to investigate its temperature evolving distinct dielectric relaxor behavior and alternating current conduction mechanism, for exploring its application as high energy storage devices. The x-ray diffraction and Raman spectroscopy was utilized to characterize exquisite phase formation of the composites. The temperature dependent dielectric properties was performed in a broad range from 100 Hz to 1 MHz and it exhibits a diffuse phase transition in high temperature region. The Non-Debye type dielectric relaxation with grain and grain boundary contribution of different activation energy was confirmed by Nyquist plot (Z′−Z′′) of impedance spectra. Broad dielectric relaxation plateau was observed in the low temperature and high frequency region and electronic hopping motion with interfacial polarization is the underlying mechanism of it, instead of dipolar relaxation and internal barrier effect. The real ac conductivity was fitted by well-known Almond-west equation and the temperature dependent frequency exponent (S) confirmed double overlapping large polaron tunneling model (OLPT) model of electrical conduction mechanism from room temperature (298 K) to 533 K. The ac activation energies varries from 0.39 eV to 0.21 eV with high frequency dispersion and variable range hoppping (VRH) model is introduced to correlate the dc conductivity.

Award for Volunteer Service to Mary K. Engelman

Mary K. Engelman is the recipient of the . Created in 2001, the award recognizes individuals who exemplify the spirit of volunteerism and have contributed significantly to the society’s goals and objectives. Engelman is being honored for her efforts in increasing public awareness of chemistry, mentorship of young scientists, and leadership of ACS activities. She retired in 2019 from her position as an innovation process manager at Eastman Chemical. “I am quite humbled,” says Engelman of receiving the award. “It’s hard to explain why you volunteer. It really is because it’s a passion inside you, that you just like to help people and you like to help organizations. I have learned so much through my volunteer efforts. It has helped me be part of a professional organization and help build a pathway into the future of ACS.” Engelman has taken on numerous roles within ACS, including as a career consultant,

Acyl-CoA Synthetase Inhibition Protects Clonal Pancreatic Beta-cell from Effects of Chronic Excess Nutrients

Abstract Objectives A single nucleotide polymorphism (SNP) in the transcription factor 7 like 2 (TCF7L2) gene is strongly associated with Type 2 Diabetes (T2D), and deletion of this SNP has been shown to reduce long chain acyl-CoA synthetase 5 (ACSL5) mRNA level. Previous research in our lab has shown chronic exposure to excess nutrients (glucose and fatty acid (FA)) increases lipid droplets in beta-cells and causes basal insulin hypersecretion, left-shifted glucose-stimulated insulin secretion (GSIS), blunted maximal GSIS and reduced insulin content. We tested the efficacy of a known phenylpyrazole-carboxamide compound (herein named ADIPO C) to reduce accumulation of intracellular lipid droplets and reverse the left-shift of GSIS in beta-cells. Methods INS-1832/13 cells were cultured in RPMI media containing 10% FBS (source of FA) and either 4 or 11 mM glucose. Insulin was measured by HTRF assay (CisBio). Intracellular lipid was detected by fluorescence microscopy using Nile red. Fluorescent Bodipy-FA was used as a surrogate FA in both ACS activity assays and lipid incorporation into cells. Oxygen consumption rate was measured using the Seahorse ion flux analyzer and intracellular calcium was measured in fura 2 loaded cells mounted on an Olympus confocal microscope. Results Adipo C (10–25 µM) acutely inhibited acyl-CoA synthetase activity by up to 40% in cell homogenates and similarly reduced FA incorporation into neutral lipids in INS-1 (832/13) cells measured using thin layer chromatography. Longer exposure (72 hrs) to ADIPO C significantly decreased intracellular lipid droplets, right-shifted GSIS and increased insulin content in cells cultured in excess nutrients. Cells cultured in excess nutrients exhibited both increased basal oxygen consumption rate and intracellular calcium oscillations, which were both reduced with 72 hrs ADIPO C incubation. Conclusions Based on these results, we conclude that Adipo C has a protective effect on beta-cells exposed to a glucolipotoxic environment and thus may prove to have therapeutic potential in the prevention/treatment of T2D. Funding Sources No funding sources to report.

Ceramide Analogue SACLAC Modulates Sphingolipid Levels and MCL-1 Splicing to Induce Apoptosis in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a disease characterized by uncontrolled proliferation of immature myeloid cells in the blood and bone marrow. The 5-year survival rate is approximately 25%, and recent therapeutic developments have yielded little survival benefit. Therefore, there is an urgent need to identify novel therapeutic targets. We previously demonstrated that acid ceramidase (ASAH1, referred to as AC) is upregulated in AML and high AC activity correlates with poor patient survival. Here, we characterized a novel AC inhibitor, SACLAC, that significantly reduced the viability of AML cells with an EC50 of approximately 3 μmol/L across 30 human AML cell lines. Treatment of AML cell lines with SACLAC effectively blocked AC activity and induced a decrease in sphingosine 1-phosphate and a 2.5-fold increase in total ceramide levels. Mechanistically, we showed that SACLAC treatment led to reduced levels of splicing factor SF3B1 and alternative MCL-1 mRNA splicing in multiple human AML cell lines. This increased proapoptotic MCL-1S levels and contributed to SACLAC-induced apoptosis in AML cells. The apoptotic effects of SACLAC were attenuated by SF3B1 or MCL-1 overexpression and by selective knockdown of MCL-1S. Furthermore, AC knockdown and exogenous C16-ceramide supplementation induced similar changes in SF3B1 level and MCL-1S/L ratio. Finally, we demonstrated that SACLAC treatment leads to a 37% to 75% reduction in leukemic burden in two human AML xenograft mouse models. IMPLICATIONS: These data further emphasize AC as a therapeutic target in AML and define SACLAC as a potent inhibitor to be further optimized for future clinical development.

Integrating physiological and metabolites analysis to identify ethylene involvement in petal senescence in Tulipa gesneriana

Flower senescence is classified into ethylene-dependent and ethylene-independent manners and determines the flower longevity which is valuable for ornamental plants. However, the manner of petal senescence in tulip is still less defined. In this study, we characterized the physiological indexes in the process of petal senescence, as well as metabolic and ethylene responses in tulip cultivar ‘American Dream’, and further identified the role of ethylene biosynthesis genes TgACS by transgenic and transient assays. Primary metabolites profiling revealed that sugars, amino acids and organic acids preferentially accumulated in senescent petals. Additionally, senescence-associated genes were identified and significantly up-regulated, coupled with increased ROS contents, rapid water loss and accelerated cell membrane breakdown. Moreover, ethylene production was stimulated as evidenced by increasing in ACS activity and ethylene biosynthesis-related genes expression. Exogenous treatment of cutting flowers with 1-MCP or ethephon resulted in delayed or enhanced petal senescence, respectively. Transient down-regulation of TgACS by VIGS assay in tulip petals delayed senescence, while over-expressed TgACS1 in tobacco promoted leaf senescence. Taken together, this study provides evidences to certify ethylene roles and TgACS functions during flower senescence in tulip.

Protein phosphatase 2A alleviates cadmium toxicity by modulating ethylene production in Arabidopsis thaliana.

Cadmium (Cd) is phytotoxic and detoxified primarily via phytochelatin (PC) complexation in Arabidopsis. Here, we explore Cd toxicity responses and defence mechanisms beyond the PC pathway using forward genetics approach. We isolated an Arabidopsis thaliana Cd-hypersensitive mutant, Cd-induced short root 1 (cdsr1) in the PC synthase mutant (cad1-3) background. Using genomic resequencing and complementation, we identified PP2A-4C as the causal gene for the mutant phenotype, which encodes a catalytic subunit of protein phosphatase 2A (PP2A). Root and shoot growth of cdsr1 cad1-3 and cdsr1 were more sensitive to Cd than their respective wild-type cad1-3 and Col-0. A mutant of the PP2A scaffolding subunit 1A was also more sensitive to Cd. PP2A-4C was localized in the cytoplasm and nucleus and PP2A-4C expression was downregulated by Cd in cad1-3. PP2A enzyme activity was decreased in cdsr1 and cdsr1 cad1-3 under Cd stress. The expression of 1-aminocyclopropane-1-carboxylic acid synthase genes ACS2 and ACS6 was upregulated by Cd more in cad1-3 and cdsr1 cad1-3 than in Col-0 and the double mutant had a higher ACS activity. cdsr1 cad1-3 and cdsr1 overproduced ethylene under Cd stress. The results suggest that PP2A containing 1A and 4C subunits alleviates Cd-induced growth inhibition by modulating ethylene production.

The characteristics of “indigenous yeast mold” dried culture using tray dryer

This research studied the effect of temperature and drying time in making “Indigenous Yeast Mold” dried culture using tray drier. There are 2 dried culture, names AC and CC. AC consists of 3 mold and 1 yeast strains, while CC consists of 7 mold and 3 yeast strains. The temperature of drying used were 40°C and 50°C and the drying time were 0, 1.5, 3, 4.5, and 6 hours. The results showed that the quality of dried cultures AC and CC were influenced by the drying times and temperatures. The water content, viability of microorganisms, Aw, and pH value decreased with the increasing of drying time and temperature. The drying time at the temperature of 40°C affected the water content and water activity of AC and CC dried culture significantly. While the drying time at the temperature of 50°C affected the moisture content, water activity, viability of microorganisms, and pH value of AC and CC dried culture significantly. The desired water content in dried culture is 10% (wb) or 11.1 (db). To reach the water content of 10%, at the drying temperature of 40 °C, the AC dried culture required 4.46 hours, while CC required 4.44 hours. Meanwhile, at the drying temperature of 50 °C, the AC dried culture took 3.46 hours, while CC required 3.33 hours. Drying could be done at 50 °C without changing the quality of the dried culture.

Electrical properties of La3+ and Y3+ ions substituted Ni0.3Cu0.3Zn0.4Fe2O4 nanospinel ferrites

La–Y substituted Ni-Cu-Zn nanospinel ferrites (NSFs) having the following formula Ni0.3Cu0.3Zn0.4LaxYxFe2−2xO4 (x = 0.0–0.10) were fabricated prepared by ultrasonic irradiation approach. The X-ray powder diffractometer (XRD), scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FT-IR) were utilized to analyze the structure, vibration bands and morphology. The impedance spectroscopy technique was used for the analysis of electrical and dielectric properties of La3+ and Y3+ ions co-substituted Ni0.3Cu0.3Zn0.4Fe2O4 NSFs. Some important parameters such as ac conductivity, activation energy, dielectric constant and dielectric loss were examined as functions of frequencies and temperatures for a variety of La and Y co-substitution ratios. In general, ac conductivity is observed to fluctuate slightly with the elevated temperatures while its fluctuation level decreases somehow with an increase in co-substitution ratios. Furthermore, the frequency dependence of dielectric functions could be described by Koop's models based on Maxwell-Wagner theory, which elucidates the correlation between the polarizability coefficient and dielectric constant in inhomogeneous double-layer structures.

Proposal for a definition for response to treatment, inactive disease and damage for JIA associated uveitis based on the validation of a uveitis related JIA outcome measures from the Multinational Interdisciplinary Working Group for Uveitis in Childhood (MIWGUC)

BackgroundJIA-associated uveitis (JIAU) is a serious, sight-threatening disease with significant long-term complications and risk of blindness, even with improved contemporary treatments. The MIWGUC was set up in order to propose specific JIAU activity and response items and to validate their applicability for clinical outcome studies.MethodsThe group consists of 8 paediatric rheumatologists and 7 ophthalmologists. A consensus meeting took place on November 2015 in Barcelona (Spain) with the objective of validating the previously proposed measures. The validation process was based on the results of a prospective open, international, multi-centre, cohort study designed to validate the outcome measures proposed by the initial MIWGUC group meeting in 2012. The meeting used the same Delphi and nominal group technique as previously described in the first paper from the MIWGUC group (Arthritis Care Res 64:1365–72, 2012). Patients were included with a diagnosis of JIA, aged less than 18 years, and with active uveitis or an uveitis flare which required treatment with a disease-modifying anti-rheumatic drug. The proposed outcome measures for uveitis were collected by an ophthalmologist and for arthritis by a paediatric rheumatologist. Patient reported outcome measures were also measured.ResultsA total of 82 patients were enrolled into the validation cohort. Fifty four percent (n = 44) had persistent oligoarthritis followed by rheumatoid factor negative polyarthritis (n = 15, 18%). The mean uveitis disease duration was 3.3 years (SD 3.0). Bilateral eye involvement was reported in 65 (79.3%) patients.The main findings are that the most significant changes, from baseline to 6 months, are found in the AC activity measures of cells and flare. These measures correlate with the presence of pre-existing structural complications and this has implications for the reporting of trials using a single measure as a primary outcome. We also found that visual analogue scales of disease activity showed significant change when reported by the ophthalmologist, rheumatologist and families.The measures formed three relatively distinct groups. The first group of measures comprised uveitis activity, ocular damage and the ophthalmologists’ VAS. The second comprised patient reported outcomes including disruption to school attendance. The third group consisted of the rheumatologists’ VAS and the joint score.ConclusionsWe propose distinctive and clinically significant measures of disease activity, severity and damage for JIAU. This effort is the initial step for developing a comprehensive outcome measures for JIAU, which incorporates the perspectives of rheumatologists, ophthalmologists, patients and families.

Dielectric relaxation and Hopping conduction mechanism in Ni1-xSrxO nanostructures

Electrical transport and conduction characteristics of sol-gel prepared Ni1-xSrxO (x = 0.00, 0.02, 0.04) nanostructures have been investigated systematically through DC and AC conduction measurements. The phase purity and structure of the samples have been studied using X-ray diffraction refinement and transmission electron microscope (TEM) analysis. It is observed that metal to semiconductor transition takes place in pure NiO sample whereas, it is suppressed on Sr insertion into NiO lattice. The activation energy (Ea) of the DC conduction have been found between 0.18 and 0.49 meV. Further, we have also observed relaxation process in doped NiO samples which are established by peaking behavior of dielectric constant. To discuss the conduction mechanism, the AC conductivity and temperature dependence of frequency exponent ‘n’ have been analysed using quantum mechanical tunnelling based Non-Overlapping Small Polaron (NSPT) model. Simultaneously, correlated AC conductivity data with NSPT model was used to calculate the value of maximum barrier height (binding energy) (Wm), AC activation energy, tunnelling distance (Rw) and density of states at Fermi level N (EF). Also, impedance spectroscopy suggests that the pure and Sr doped samples exhibit high order insulating behavior at the temperatures of 30 °C and 150 °C.

High electrical conductivity of (1-x)NiO/xFe2O3(x = 0.0, 0.3, 0.5, 0.7 and 1) nanoparticles for solid-state electronics

Abstract The mixed metal oxides have a significant increase in material science engineering applications. Mixed metal oxides of (1-x)NiO/xFe2O3 nanoparticles (NPs) (x = 0.0, 0.3, 0.5, 0.7 and 1) were obtained by the mechanical mixing method, and their films were achieved by the drop coating method. Raman spectroscopy was used for identifying these NPs. Dielectric relaxation and ac conductivity behavior of (1-x)NiO/xFe2O3 NPs (x = 0.0, 0.3, 0.5, 0.7 and 1) were studied. The dielectric constant, e1, and the dielectric loss, e2, for pure Fe2O3 NPs were found higher than that for pure NiO NPs. Moreover, with increasing the concentration of Fe2O3 NPs, the value of e1 and e2 increased in the mixed (1-x)NiO/xFe2O3 NPs. The complex dielectric modulus the real, M1, and imaginary, M2, parts were investigated as well as the dielectric relaxation time. The total conductivity was investigated as a function of frequency for (1-x)NiO/xFe2O3 NPs (x = 0.0, 0.3, 0.5, 0.7 and 1) then the improvement of its values was verified due to the addition of Fe2O3 NPs. The AC activation energy, ΔEac, was calculated, which increases (0.0081–0.0090) at a constant frequency of 1 MHz as Fe2O3 NPs content increased. These values of ΔEac reflected that the hopping conduction is the common current transport mechanism. On the other hand, the activation energy of the relaxation process, ΔEr, decreased (0.875–0.322) as a function of Fe2O3 NPs content increased.

Glucagon up-regulates hepatic mitochondrial pyruvate carrier 1 through cAMP-responsive element-binding protein; inhibition of hepatic gluconeogenesis by ginsenoside Rb1.

Hepatic mitochondrial pyruvate carrier (MPC) transports pyruvate into mitochondria. This study investigated the involvement of MPC1 in hepatic glucagon response, in order to identify a possible pharmacological intervention. The correlation between hepatic glucagon response and MPC1 induction was investigated in fasted mice and primary hepatocytes. The effects of ginsenoside Rb1 on MPC1 function were observed. Glucagon challenge raised blood glucose with hepatic MPC1 induction, and inhibition of MPC induction coincided with a reduced rise in blood glucose. cAMP-responsive element-binding protein (CREB) knockdown blocked glucagon-induced MPC1 expression, while CREB overexpression increased MPC1 expression. Luciferase reporter, chromatin immunoprecipitation assay, and promoter mutation confirmed that CREB increased MPC1 transcription through gene promoter induction. CREB regulated transcription co-activator 2 nuclear translocation was also required for CREB to promote MPC1 induction. Glucagon shifted mitochondrial pyruvate towards carboxylation for gluconeogenesis via the opposite regulation of pyruvate dehydrogenase and carboxylase with respect to MPC1 induction. MPC1 induction was necessary for glucagon to promote pyruvate-driven hepatic glucose production (HGP), but glucagon failed to influence HGP from other gluconeogenic substrates routed into the tricarboxylic acid cycle, independent of MPC. Rb1 blocked cAMP signalling by inhibiting AC activity and deactivated CREB by dephosphorylation, possibly contributing to inhibiting MPC1 induction to reduce HGP. CREB transcriptionally up-regulates MPC1 to provide pyruvate for gluconeogenesis. Rb1 reduced cAMP formation which consequently reduced CREB-mediated MPC1 induction and thereby might contribute to limiting pyruvate-dependent HGP. These results suggest a therapeutic strategy to reduce hyperglycaemia in diabetes.

Sheep and goats raised in mixed flocks have diverse immune status around parturition

Several physiological and metabolic changes take place in dairy ruminants around parturition (late pregnancy, parturition, and early lactation). Dairy species are genetically selected for their higher milk production compared with non-dairy species. This fact causes a constant stress that impairs the immune status of the animal, with consequences for its welfare and performance. In the present study, we assessed the immune status of high-yield dairy sheep and goats by quantifying IgG and IgM concentrations, as well as chitotriosidase (ChT) and complement system [total complement system (TC) and alternative complement pathway (AC)] activity in blood plasma around parturition. We also measured IgG and IgM concentrations and ChT activity in colostrum and milk during the first 40 d postpartum. The lowest blood IgG concentration was at parturition in both species. We detected no differences in blood IgG concentrations between species. Blood IgM concentrations were constant in both species throughout the study period. However, blood IgM concentrations were greater in sheep than in goats. Blood ChT activity was greater in goats than in sheep, and both species showed constant activity of this enzyme throughout the study period. We observed no differences in complement system (TC and AC) activity between sheep and goats. In addition, both TC and AC activity were constant in both species throughout the experiment. In general, IgG and IgM concentrations were greater in sheep colostrum than in goat colostrum, but these differences disappeared after d 4 (IgG) and d 3 (IgM) postpartum. In both species, the highest IgG and IgM concentrations were measured in colostrum, gradually decreasing during the first days postpartum. Chitotriosidase activity decreased in both species from colostrum to milk, although goats always showed greater ChT activity than sheep. Both sheep and goats seemed to be more susceptible to infectious diseases around parturition. As well, goats showed greater ChT activity in blood, colostrum, and milk than sheep. This fact may give these animals additional protection against parasite and fungal infections.