Study of the composition and structure of ion-conducting membranes based on polyvinyl alcohol by 1H NMR spectroscopy

One of the alternative types of proton-conducting membranes for a hydrogen-air solid polymer fuel cell is the type of hybrid membranes based on polyvinyl alcohol (PVA) crosslinked with aldehyde, modified by sulfonic acid. Earlier, for the first time, we obtained new ion – conducting membranes based on furfural-crosslinked PVA modified aminosulfonic acid (ASA) and tetraethoxysilane (TEOS), as well as membranes not crosslinked with furfural (FUR) or unmodified ASA and TEOS, by a liquid-phase synthesis method, in an organic medium-dimethyl sulfoxide. The values of their ionic conductivity and the degree of swelling in water are presented. In this work, the composition and structure of the obtained ion-conducting membranes are studied using liquid-phase nuclear magnetic resonance (NMR) spectroscopy on ¹H nuclei. In the ¹H NMR spectrum of an ion – conducting membrane not cross-linked with the «PVA/ASA», the signal of free OH groups of PVA is observed to disappear, but at the same time a characteristic triplet at 7.1 ppm. is preserved, having a constant of ～51 Hz and components of the same intensity (1:1:1), which corresponds to protons of ¹⁴NH₄⁺ hydrolyzed ASA. The disappearance of the expanded signal at 9.6 m. d. of protons of the free sulfo group of ASA and a narrow singlet signal at 5.8 m. d. of free protons of the NH₂ group of ASA indicates the interaction of ASA with OH groups of PVA. In the ¹H NMR spectrum of an ion – conducting membrane crosslinked with FUR – «PVA/ASA/FUR», signals of protons of the furan ring of FUR and a signal of its aldehyde group are observed, which is shifted to a strong field, which is determined by the formation of a chemical bond between FUR and the polymer chain of PVA. In the ¹H NMR spectra of all membranes modified by ASA, the appearance of a second weaker-field ¹⁴NH₄⁺ triplet is observed, and in the spectra of a number of ion – conducting hybrid membranes modified by TEOS – «PVA/ASA/FUR/TEOS», signals of the third type of ¹⁴NH₄⁺ triplets shifted in a strong field relative to the other two ¹⁴NH₄⁺ triplets were detected. The appearance of additional ¹⁴NH₄⁺ triplets indicates the formation of several bound forms of the ammonium ion.     

Dynamic modelling of PEM fuel cell system for simulation and sizing of marine power systems

This article presents a model of a proton exchange membrane fuel cell (PEMFC) system for marine power systems. PEMFC in marine hybrid power sources can have various power ranges and capacities in contrast with vehicle applications. Investigating PEMFCs behaviour and performance for various conditions and configurations is demanded for proper sizing and feasibility studies. Hence, modelling and simulation facilitate understanding the performance of the PEMFC behaviour with various sizes and configurations in power systems. The developed model in this work has a system level fidelity with real time capabilities, which can be utilized for simulator approaches besides quasi-static studies with a power-efficiency curve. Moreover, the model can be used for scaling the PEMFC power range by considering transient responses and corresponding efficiencies. The Bond graph approach as a multi-disciplinary energy based modelling strategy is employed for the PEMFC as a multi domains system. In the end, various PEMFC cell numbers and compressor sizes have been compared with power-efficiency curves and transient responses in a benchmark.     

Fabrication of CuInS2/CNTs absorber layers by sol–gel method

In this work, CuInS₂/multiwalled carbon nanotube (MWCNT) layers are fabricated by the sol–gel spin-coating method. We introduce two forms of MWCNTs into a CIS₂ solution, washed functional multiwalled carbon nanotubes (W-FMWCNTs) and unwashed-functional multiwalled carbon nanotubes (UW-FMWCNTs), in order to investigate the effects of MWCNTs and an acidic environment on the physical properties of the CIS₂ absorber layers. The structure and morphology of the samples are investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The XRD study shows that all samples crystallize in a tetragonal structure. The results obtained from the optical, thermo-electric, and electrical measurements indicate that the two groups of CIS₂ layers prepared using W- and UW-FMWCNTs show the opposite behaviors. The Seebeck coefficient (SC) measurements indicate possible formation of a p–n junction.     

Piperine Targets Different Drug Resistance Mechanisms in Human Ovarian Cancer Cell Lines Leading to Increased Sensitivity to Cytotoxic Drugs

Our goal was to examine the anticancer effects of piperine against the resistant human ovarian cancer cells and to explore the molecular mechanisms responsible for its anticancer effects. Our study used drug-sensitive ovarian cancer cell line W1 and its sublines resistant to paclitaxel (PAC) and topotecan (TOP). We analyzed the cytotoxic effect of piperine and cytostatic drugs using an MTT assay. The impact of piperine on protein expression was determined by immunofluorescence and Western blot. We also examined its effect on cell proliferation and migration. We noticed a different level of piperine resistance between cell lines. Piperine increases the cytotoxic effect of PAC and TOP in drug-resistant cells. We observed an increase in PTPRK expression correlated with decreased pTYR level after piperine treatment and downregulation of P-gp and BCRP expression. We also noted a decrease in COL3A1 and TGFBI expression in investigated cell lines and increased COL3A1 expression in media from W1PR2 cells. The expression of Ki67 protein and cell proliferation rate decreased after piperine treatment. Piperine markedly inhibited W1TR cell migration. Piperine can be considered a potential anticancer agent that can increase chemotherapy effectiveness in cancer patients.     

Aerobic Exercise Ameliorates Cancer Cachexia-Induced Muscle Wasting through Adiponectin Signaling

Cachexia is a multifactorial syndrome characterized by muscle loss that cannot be reversed by conventional nutritional support. To uncover the molecular basis underlying the onset of cancer cachectic muscle wasting and establish an effective intervention against muscle loss, we used a cancer cachectic mouse model and examined the effects of aerobic exercise. Aerobic exercise successfully suppressed muscle atrophy and activated adiponectin signaling. Next, a cellular model for cancer cachectic muscle atrophy using C2C12 myotubes was prepared by treating myotubes with a conditioned medium from a culture of colon-26 cancer cells. Treatment of the atrophic myotubes with recombinant adiponectin was protective against the thinning of cells through the increased production of p-mTOR and suppression of LC3-II. Altogether, these findings suggest that the activation of adiponectin signaling could be part of the molecular mechanisms by which aerobic exercise ameliorates cancer cachexia-induced muscle wasting.     

Effect of air addition to the air electrode on the stability and efficiency of carbon dioxide electrolysis by solid oxide cells

In this study, the effect of air addition to the air electrode on the long-term stability and efficiency of solid oxide cells for CO₂ electrolysis, with 23.8% CO as protective gas in the fuel electrode, has been investigated. The results show that without continuous purging of the air in the air electrode (Cell-1), the degradation rate was 8.37%/kh in the 1070 h electrolysis process, while with 5 L/min air supplied to the air electrode (Cell-2), the degradation rate was 24.41%/kh. Impedance analysis indicates that the degradation of Cell-1 was mainly because of the increase in O^2? exchange polarization impedance, while the degradation of Cell-2 was caused mainly by the variation of ohmic impedance. The microstructural characterization indicated a decrease in active Ni in the fuel electrode in both Cell-1 and Cell-2, but the degree of nickel loss depended on the test time. At the outlet of the Cell-2, the appearance of carbon further explains the faster degradation rate, although the carbon deposition was not directly caused by the introduction of air into the air electrode. Energy spectral analysis shows that the air electrode in Cell-1 generated Sr rich phases, which indicates that the absence of air in the air electrode in the electrolysis process indeed causes more serious microstructure damage. The energy conversion efficiency could exceed 86% if the energy consumed for heating the air is ignored. This work provides a scenario for the application of solid oxide cells for CO₂ electrolysis without air purging in the air electrode.     

Feasibility assessment of a container ship applying ammonia cracker-integrated solid oxide fuel cell technology

The maritime industry has entered its pathway of decarbonization. To achieve the IMO's ambitious goals of an absolute emissions reduction of 50% by 2050, and a 70% carbon intensity reduction by 2050 compared to the 2008 level, various options for the adoption of technologies and alternative fuels are considered by the market stakeholders.Ammonia, one of the most promising alternative marine fuels has long been considered to reduce carbon emissions. And solid oxide fuel cell is expected to transform ship propulsion technology in the future due to its high utilization of fuels. In this paper, a feasibility study is performed to assess the application of an ammonia cracker-integrated solid oxide fuel cell (hereafter as Ammonia SOFC) system on an ocean-going vessel through a detailed CAPEX, FuelEX, OPEX, Carbon tax, and carbon emission analysis. Comparison is made with direct ammonia, LNG and conventional fuels fired heat engines. The result concludes that it can be economically viable to apply to deep-sea shipping, compared to other marine fuels and propulsion technologies.     

Design of Ag nanograting for broadband absorption enhancement in amorphous silicon thin film solar cells

Light trapping is one of the key issues to improve the light absorption and increase the efficiency of thin film solar cells. The effects of the triangular Ag nanograting on the absorption of amorphous silicon solar cells were investigated by a numerical simulation based on the finite element method. The light absorption under different angle and area of the grating has been calculated. Furthermore, the light absorption with different incident angle has been calculated. The optimization results show that the absorption of the solar cell with triangular Ag nanograting structure and anti-reflection film is enhanced up to 96% under AM1.5 illumination in the 300–800 nm wavelength range compared with the reference cell. The physical mechanisms of absorption enhancement in different wavelength range have been discussed. Furthermore, the solar cell with the Ag nanograting is much less sensitive to the angle of incident light. These results are promising for the design of amorphous silicon thin film solar cells with enhanced performance.     

Polyamide-coated Nafion composite membranes with reduced hydrogen crossover produced via interfacial polymerization

Nafion, a perfluoro-sulfonic acid (PFSA)-based polymer, is a promising material that will help realize the commercialization of proton exchange membrane-based fuel cells (PEMFCs) and proton exchange membrane water electrolyzers (PEMWEs). However, Nafion also exhibits reduced mechanical and dimensional stability and increased hydrogen crossover under cell operating conditions in real operational settings, that is, in a hydrated state or in water at 60–80 °C. These factors may negatively affect cell efficiency and durability and thus must be addressed. To overcome these limitations, polyamide-coated Nafion composite membranes were developed for the first time via interfacial polymerization. 3,5-Diaminobenzoic acid (DABA), which contains carboxyl functional groups, was used as a monomer to add hydrophilicity to the membrane, and the coating layer thickness was controlled by adjusting the DABA content. A nanoscale polyamide (PA) layer was coated on the surface of Nafion-212 to fabricate a membrane, PA-c3-Nafion. PA-c3-Nafion was found to show ion conductivity 13.6% higher than that of a pristine Nafion-212 membrane at 80 °C, while providing improved mechanical performance and dimensional stability. In particular, at 95% RH, the hydrogen permeability of PA-c3-Nafion was 16.4% lower than that of Nafion-212 while, in a fully hydrated state, the hydrogen permeability of PA-c3-Nafion was 21.2% lower than that of Nafion-212. The LSV test results also showed that the degree of hydrogen crossover was significantly lower in PA-c3-Nafion than in Nafion-212.     

Activation of the Complement System on Human Endothelial Cells by Urban Particulate Matter Triggers Inflammation-Related Protein Production

Exposure to particulate matter (PM) is becoming a major global health issue. The amount and time of exposure to PM are known to be closely associated with cardiovascular diseases. However, the mechanism through which PM affects the vascular system is still not clear. Endothelial cells line the interior surface of blood vessels and actively interact with plasma proteins, including the complement system. Unregulated complement activation caused by invaders, such as pollutants, may promote endothelial inflammation. In the present study, we sought to investigate whether urban PM (UPM) acts on the endothelial environment via the complement system. UPM-treated human endothelial cells with normal human serum showed the deposition of membrane attack complexes (MACs) on the cell surface via the alternative pathway of the complement system. Despite the formation of MACs, cell death was not observed, and cell proliferation was increased in UPM-mediated complement activation. Furthermore, complement activation on endothelial cells stimulated the production of inflammation-related proteins. Our results revealed that UPM could activate the complement system in human endothelial cells and that complement activation regulated inflammatory reaction in microenvironment. These findings provide clues with regard to the role of the complement system in pathophysiologic events of vascular disease elicited by air pollution.