Arsenic (As) is a ubiquitous environmental toxin and robust inducer of oxidative stress (OxS). Copper (Cu) is an essential microelement, which participates in OxS as a cofactor for certain enzymes, ...with narrow optimal range between essential and toxic concentrations. However, their effects are rarely studied in chicken skeletal muscles, which have soaring per capita consumption andare susceptible to oxidative damage. In the present study, we demonstrated that the administration of copper sulfate (300 mg kg−1) or arsenite (30 mg kg−1) individually or their co-administration leads to varying degrees of OxS in the skeletal muscles of chickens. Corresponding to the protein expression pattern, the mRNA levels of caspase, B-cell lymphoma-2 (Bcl-2) families, and autophagy-related genes were also compromised in the experimental groups, indicating the involvement of both apoptotic and autophagic cell death. Additionally, rampant mitochondrial fission caused the vicious cycle between imbalanced mitochondrial dynamics and OxS, thus tethering intracellular homeostasis. The abovementioned muscle damage and index anomalies were time dependent, and more deteriorated effects were observed in Cu2+ and arsenite co-administered groups than those in groups administered Cu2+ and arsenite alone. Intriguingly, in the studied skeletal muscles, namely wing biceps brachii and leg gastrocnemius, there were conspicuous differences in oxidative toxicity susceptibility, which needs further study. The present study showed that Cu and/or As induce oxidative damage in chicken skeletal muscles and discussed its mechanism in terms of apoptosis, autophagy, and mitochondrial dynamics, thus voicing concerns about poultry breeding areas cross-contaminated with Cu2+ and arsenite.
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•Myoblasts suffer more damage from arsenic than that from copper at the same time point.•Copper exposure provokes an oxidative burden, thus potentiating arsenic toxicity.•Leg gastrocnemius are more vulnerable to oxidative stress than wing biceps.
A series of Eu2+- and Mn2+-coactivated CaAl2Si2O8 phosphors have been synthesized at 1400 °C under a reduced atmosphere and their luminescence properties have been investigated as a function of ...activator and coactivator concentrations. We have discovered that energy transfers from Eu2+ to Mn2+ by directly observing significant overlap of the excitation spectrum of Mn2+ and the emission spectrum of Eu2+ as well as the systematic relative decline and growth of emission bands of Eu2+ and Mn2+, respectively. The critical distance and average separation of Eu2+ and Mn2+ have also been calculated. By utilizing the principle of energy transfer, we have also demonstrated that with appropriate tuning of activator content CaAl2Si2O8:Eu2+,Mn2+ phosphors exhibit great potential to act as a phosphor for white-light ultraviolet light-emitting diodes (UVLEDs).
In this manuscript, a simple method combining atomic layer deposition and magnetron sputtering is developed to fabricate high-performance Pd/SnO2 film patterns applied for micro-electro-mechanical ...systems (MEMS) H2 sensing chips. SnO2 film is first accurately deposited in the central areas of MEMS micro hotplate arrays by a mask-assistant method, leading the patterns with wafer-level high consistency in thickness. The grain size and density of Pd nanoparticles modified on the surface of the SnO2 film are further regulated to obtain an optimized sensing performance. The resulting MEMS H2 sensing chips show a wide detection range from 0.5 to 500 ppm, high resolution, and good repeatability. Based on the experiments and density functional theory calculations, a sensing enhancement mechanism is also proposed: a certain amount of Pd nanoparticles modified on the SnO2 surface could bring stronger H2 adsorption followed by dissociation, diffusion, and reaction with surface adsorbed oxygen species. Obviously, the method provided here is quite simple and effective for the manufacturing of MEMS H2 sensing chips with high consistency and optimized performance, which may also find broad applications in other MEMS chip technologies.
Glutathione-bound gold nanoclusters (AuNCs@GSH) can emit reddish photoluminescence under illumination of ultraviolet light. The luminescence of the AuNCs@GSH is quenched when chelating with iron ions ...(AuNCs@GSH-Fe3+), presumably resulting from the effective electron transfer between the nanoclusters and iron ions. Nevertheless, we found that the luminescence of the gold nanoclusters can be restored in the presence of phosphate-containing molecules, which suggested the possibility of using AuNCs@GSH-Fe3+ complexes as the selective luminescent switches for phosphate-containing metabolites. Phosphate-containing metabolites such as adenosine-5′-triphosphate (ATP) and pyrophosphate play an important role in biological systems. In this study, we demonstrated that the luminescence of the AuNCs@GSH-Fe3+ is switched-on when mixing with ATP and pyrophosphate, which can readily be observed by the naked eye. It results from the high formation constants between phosphates and iron ions. When employing fluorescence spectroscopy as the detection tool, quantitative analysis for phosphate-containing metabolites such as ATP and pyrophosphate can be conducted. The linear range for ATP and pyrophosphate is 50 μM to sub-millimolar, while the limit of detection for ATP and pyrophosphate are ∼43 and ∼28 μM, respectively. Additionally, we demonstrated that the luminescence of the AuNCs@GSH-Fe3+ can also be turned on in the presence of phosphate-containing metabolites from cell lysates and blood plasma.
Staphylococcus aureus is one of the most frequently occurring hospital- and community-associated pathogenic bacteria featuring high morbidity and mortality. The occurrence of methicillin-resistant S. ...aureus (MRSA) has increased persistently over the years. Therefore, developing novel anti-MRSA drugs to circumvent drug resistance of S. aureus is highly important. Roemerine, an aporphine alkaloid, has previously been reported to exhibit antibacterial activity. The present study aimed to investigate whether roemerine can maintain these activities against S.aureus in vivo and further explore the underlying mechanism. We found that roemerine is effective in vitro against four S. aureus strains as well as in vivo against MRSA insepticemic BALB/c mice. Furthermore, roemerine was found to increase cell membrane permeability in a concentration-dependent manner. These findings suggest that roemerine may be developed as a promising compound for treating S. aureus, especially methicillin-resistant strains of these bacteria.
The performance of dye-sensitized solar cells (DSSC), made of highly ordered anodic titanium oxide (ATO) nanotube (NT) arrays produced directly on Ti foil, depends on the length of these arrays. We ...controlled these lengths L from 4 to 41 μm while varying the concentration (0.1, 0.25, 0.5, and 0.8 wt %) of the electrolyte (NH4F) in ethylene glycol in the presence of H2O (2 vol %) with anodization for various periods (t = 0.5−8 h). The compact and bundle layers introduced during anodization were effectively removed upon simple ultrasonic cleaning in deionized water containing submicrometer particles of Al2O3 in a small proportion. The photovoltaic performance of the NT-DSSC devices (NH4F at 0.5 wt %) made of ATO films, as prepared, increased from 3.0% to 5.2% as L was increased from 6 μm (t = 0.5 h) to 30 μm (t = 8 h). After treatment of the ATO films with TiCl4 in a two-step annealing process, the optimized NT-DSSC device attained an overall efficiency of 7.0% power conversion.
Mid-infrared (MIR) frequency combs based on integrated photonic microresonators (micro combs) have attracted increasing attention in chip-scale spectroscopy due to their high spectral resolution and ...broadband wavelength coverage. However, up to date, there are no perfect solutions for the effective generation of MIR micro combs because of the lack of proper MIR materials as the core and cladding of the integrated microresonators, thereby hindering accurate and flexible dispersion engineering. Here, we have firstly demonstrated a MIR micro comb generation covering from 6.94 μm to 12.04 μm based on a sandwich-integrated all-ChG microresonator composed of GeAsTeSe and GeSbSe as the core and GeSbS as cladding. The novel sandwich microresonator is proposed to achieve a symmetrically uniform distribution of the mode field in the microresonator core, precise dispersion engineering, and low optical loss, which features a wide transmission window, high Kerr nonlinearity, and hybrid-fabrication flexibility on a silicon wafer. A MIR Kerr frequency comb with a 5.1 μm bandwidth has been numerically demonstrated, assisted by dispersive waves. Additionally, a feasible fabrication scheme is proposed to realize the on-demand ChG microresonators. These demonstrations characterize the advantages of integrated ChG photonic devices in MIR nonlinear photonics and their potential applications in MIR spectroscopy.
In order to understand the effects of meso-substituents of the zinc porphyrins on optical, electrochemical, and photovoltaic properties, a series of porphyrins with different combinations of thienyl ...(S) and p-carboxyphenyl (A) groups as the meso substituents have been systematically synthesized and studied. The properties of zinc complexes 3S1A, trans-2S2A, cis-2S2A, and 1S3A were fully investigated by absorption and emission spectra, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra, density functional theory (DFT) calculations, electrochemical, photophysical, and photovoltaic measurements. With the increasing number of meso-thienyl groups, slight red-shifts of Soret and Q bands were observed in both absorption and emission spectra. All of the absorption spectra of zinc porphyrins on TiO2 film show broadening and splitting of Soret bands because of excitonic coupling of porphyrins. ATR-FTIR spectra revealed likely modes to determine either a single arm (in 3S1A and trans-2S2A) or double arms (in 1S3A and cis-2S2A) attached on TiO2. Two factors of p-carboxyphenyl and thienyl groups affecting the devices performanceheavy atom effect and the amount of dye loading on TiO2are concluded. Overall, the power conversion efficiencies (η) of the devices exhibit the following order: 1S3A (3.0%) > cis-2S2A (2.5%) > trans-2S2A (1.8%) ≫ 3S1A (0.2%).
Background
The transient receptor potential vanilloid type 1 (TRPV1) is expressed in the cardiovascular system, and increased TRPV1 expression has been associated with cardiac hypertrophy. ...Nevertheless, the role of TRPV1 in the pathogenesis of cardiac hypertrophy and the underlying molecular mechanisms remain unclear.
Methods and Results
In cultured cardiomyocytes, activation of TRPV1 increased cell size and elevated expression of atrial natriuretic peptide mRNA and intracellular calcium level, which was reversed by TRPV1 antagonist capsazepine. Increased expression of phosphorylated calmodulin‐dependent protein kinase IIδ and mitogen‐activated protein kinases were found in TRPV1 agonist capsaicin‐treated cardiomyocytes. Selective inhibitor of calmodulin‐dependent protein kinase IIδ decreased phosphorylation of extracellular signal–regulated kinases and p38. Capsaicin induced an increase in expression of ornithine decarboxylase protein, which is the key enzyme in polyamine biosynthesis in cardiomyocytes. Nevertheless, there was no obvious change of ornithine decarboxylase expression in TRPV1 knockdown cells after capsaicin treatment, and specific inhibitors of calmodulin‐dependent protein kinase IIδ or p38 downregulated the capsaicin‐induced expression of ornithine decarboxylase. Capsazepine alleviated the increase in cross‐sectional area of cardiomyocytes and the ratio of heart weight to body weight and improved cardiac function, including left ventricular internal end‐diastolic and ‐systolic dimensions and ejection fraction and fractional shortening percentages, in mice treated with transverse aorta constriction. Capsazepine also reduced expression of ornithine decarboxylase and cardiac polyamine levels. Transverse aorta constriction induced increases in phosphorylated calmodulin‐dependent protein kinase IIδ and extracellular signal–regulated kinases, and p38 and Serca2a were attenuated by capsazepine treatment.
Conclusions
This study revealed that the mitogen‐activated protein kinase signaling pathway and intracellular polyamines are essential for TRPV1 activation–induced cardiac hypertrophy.
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