Search Results (10)

Psoriasis and psoriatic arthritis (PsA) are chronic autoimmune diseases characterized by persistent inflammation and oxidative imbalance. Oxidative stress, caused by excessive production of reactive oxygen species (ROS) and dysfunction in antioxidant mechanisms, plays a critical role in the pathogenesis of both conditions, leading to increased inflammatory processes and tissue damage. This study aims to review current antioxidant-based therapeutic options and analyze oxidative stress biomarkers in the context of psoriasis and PsA. Based on available literature, key biomarkers, such as malondialdehyde (MDA), advanced glycation end-products (AGEs), and advanced oxidation protein products (AOPP), were identified as being elevated in patients with psoriasis and PsA. Conversely, antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), showed reduced activity, correlating with symptom severity. The study also examines the efficacy of various antioxidant therapies, including curcumin, resveratrol, coenzyme Q10, and vitamins C and E, which may aid in reducing oxidative stress and alleviating inflammation. The findings indicated that antioxidants can play a significant role in alleviating symptoms and slowing the progression of psoriasis and PsA through modulation of redox mechanisms and reduction of ROS levels. Antioxidant-based therapies offer a promising direction in treating autoimmune diseases, highlighting the need for further research on their efficacy and potential clinical application. Full article

In oxygen production on plateaus, pressure swing adsorption (PSA) oxygen production is currently the most commonly used oxygen production method. In plateau regions, low pressure leads to a decrease in adsorbent nitrogen–oxygen separation performance, which affects the performance of PSA oxygen production, so it is particularly important to enhance adsorbent nitrogen–oxygen separation performance. In this paper, Li-LSX (lithium low-silicon aluminum X zeolite molecular sieve) adsorbents were modified using the liquid phase ion exchange method, and five kinds of modified adsorbents were obtained, namely AgLi-LSX, CaLi-LSX, ZnLi-LSX, CuLi-LSX, and FeLi-LSX, respectively. The influences of different metal ions and modification time lengths on the adsorbent nitrogen adsorption and nitrogen–oxygen separation coefficients were analyzed. Through theoretical calculations, the nitrogen and oxygen adsorption and separation performances of the modified adsorbents at different altitudes and low adsorption pressures were investigated. It is shown that the nitrogen adsorption capacity of the AgLi-LSX-1 adsorbent obtained from the modification experiment reaches 27.92 mL/g, which is 3.24 mL/g higher than that of Li-LSX; the nitrogen–oxygen separation coefficients of S1 and S2 are 19.24 and 7.54 higher, respectively; and the nitrogen–oxygen separation coefficients of S4 are 20.85 and 7.54 higher than those of Li-LSX, respectively. With the increase in altitude from 50 m to 5000 m, the nitrogen–oxygen separation coefficient of the AgLi-LSX-1 adsorbent increased rapidly from 20.85 to 57, and its nitrogen–oxygen separation coefficient S4 exceeded that of the Li-LSX adsorbent to reach 47.61 at an altitude of 4000 m. Therefore, the modified adsorbent AgLi-LSX-1 in this paper can enhance the performance of the PSA oxygen process for oxygen production in plateau applications. Full article

Rapid-cycle pressure swing adsorption (PSA) with small adsorbents particles is intended to improve mass transfer rate and productivity. However, the mass transfer mechanisms are changed with reduction of particle size during rapid-cycle adsorption process. A heat and mass transfer model of rapid-cycle PSA air separation process employing small LiLSX zeolite particles is developed and experimentally validated to numerically analyze the effects of mass transfer resistances on the characteristics of cyclic adsorption process. Multicomponent Langmuir model and linear driving force model are employed for characterizing the adsorption equilibrium and kinetic. The results of numerical analysis demonstrate that the dominant mass transfer resistance of small adsorbents particles is a combination of film resistance, axial dispersion effect and macropore diffusion resistance. The oxygen purity, recovery and productivity of the product are overestimated by ~2–4% when the effect of axial dispersion on mass transfer is ignored. As particle size decreases, the front of nitrogen-adsorbed concentration and gas temperature become sharp, which effectively improves the performance. However, the adverse effect of axial dispersion on the mass transfer becomes significant at very small particles conditions. It is nearly identical shapes of nitrogen concentration and gas temperature profiles after adsorption and desorption steps. The profiles are pushed forward near the production end with an increase in bed porosities. The optimal oxygen recovery and productivity are achieved with a particle diameter of 0.45 mm and bed porosity of 0.39 during the PSA process. Full article

In this review, the authors conducted benchmarks for three thermodynamic models to analyze PSA-based medical oxygen concentrator (MOC) systems to allow for optimization and operational flexibility. PSA oxygen generator plants are good medical-grade oxygen sources, a crucial tool in healthcare from the primary to the tertiary level. However, they must be designed accordingly and properly operated, considering key design goals such as improving adsorbent productivity, improving oxygen recovery, and innovating to reduce unit size and weight. The importance of mapping the performance of various design and operating requirements or designs themselves on outlet product specifications and production effectiveness is outlined. Emphasizing optimal PSA design and operation, the authors suggest considering simulation-based optimization frameworks or high-fidelity modeling for the optimal layout and operation conditions of adsorption-based MOC systems. Notwithstanding, a simplified first-principles-based model with additional assumptions and simplifications generates a large volume of scenarios faster. Therefore, it represents a good approach for a feasibility study dealing with many options and designs or even the real-time monitoring of PSA operating conditions. All this paved the way for efficient translation into machine learning models and even deep learning networks that might be better suited to simulate the complex PSA process. The conclusion outlines that PSA-based plants can be flexible and effective units using any of the three models when properly optimized. Full article

Pseudomonas syringae pv. actinidiae (Psa), a bacterial pathogen, is a severe threat to kiwifruit production. To elucidate the species-specific interaction between Psa and kiwifruit, transcriptomic-profiles analyses were conducted, under Psa-infected treatment and mock-inoculated control, on shoots of resistant Maohua (MH) and susceptible Hongyang (HY) kiwifruit varieties. The plant hormone-signal transduction and plant–pathogen interaction were significantly enriched in HY compared with MH. However, the starch and sucrose metabolism, antigen processing and presentation, phagosome, and galactose metabolism were significantly enriched in MH compared with HY. Interestingly, the MAP2 in the pathogen/microbe-associated molecular patterns (PAMPs)-triggered immunity (PTI) was significantly up-regulated in MH. The genes RAR1, SUGT1, and HSP90A in the effector-triggered immunity (ETI), and the NPR1 and TGA genes involved in the salicylic acid signaling pathway as regulatory roles of ETI, were significantly up-regulated in HY. Other important genes, such as the CCRs involved in phenylpropanoid biosynthesis, were highly expressed in MH, but some genes in the Ca²⁺ internal flow or involved in the reactive oxygen metabolism were obviously expressed in HY. These results suggested that the PTI and cell walls involved in defense mechanisms were significant in MH against Psa infection, while the ETI was notable in HY against Psa infection. This study will help to understand kiwifruit bacterial canker disease and provide important theoretical support in kiwifruit breeding. Full article

Today, there are new technologies to produce bioethanol: one of them is the Pressure Swing Adsorption (PSA) process. This process has displaced other separation technologies due to the use of natural adsorbents and its methodology to obtain high purities with a lower energy cost. The aim of this work focuses on the optimization of the PSA process (experimental case) to obtain a higher recovery and production of bioethanol using lower energy consumption. The results are favorable since the energy cost is reduced to a range of 60% and 62%, obtaining purities above 99% wt of ethanol and recovery between 75% and 77.41%. The bioethanol produced and purified in the different scenarios meets international standards to be used as a fuel or oxygenating additive. Full article

This study applies the Physical Optimum (PhO) as a reference value to rate the efficiency of two technical options for the oxygen supply of a hospital. The systematic comparison of the alternative processes using the PhO as a benchmark for the minimum input (exergy in this case) required to run a process with a certain benefit allows to determine the potential for optimization of each technology. Differences are analyzed by visualizing the losses of each individual production step in a process as well as by the resulting overall energy demand, including the primary energy. Possible alternatives are purchasing liquid oxygen from a cryogenic process or the production by means of Pressure Swing Adsorption (PSA) on site. The cryogenic production shows a lower exergy demand even though it also has a higher potential for optimization. Yet, the total losses, significantly impacted by the unavoidable transportation, sum up, resulting in the conclusion that the PSA is the preferable option overall, considering energy aspects. Finally, additional criteria such as economic, legal, and structural consequences of the respective choices are briefly outlined. Full article

Radial flow is an important type of flow direction for large-scale pressure swing adsorption (PSA) oxygen generation systems. In this study, a numerical simulation of a PSA oxygen generation process based on radial-flow adsorbers was performed with two-dimensional CFD modeling. The gas distribution, the maldistribution factor and the pressure difference were comparatively investigated at each flow type of the radial-flow adsorber. Considering the gas adsorption performance, the results indicated that the centripetal π-flow radial adsorber has the best flow characteristics for the PSA process. The oxygen purity distribution within the adsorption bed was studied to compare centripetal and centrifugal π-flows, and the former was shown to perform better on oxygen enrichment and adsorbent desorption. The steady state was achieved after eight cycles for the centripetal-π adsorber and each of the four steps of the PSA process was explored in detail to show the advantageous properties for oxygen generation in terms of adsorption and desorption. The relationships between the product flow rate and the oxygen purity and recovery were further investigated. Full article

Oxy-fuel combustion is one of the most promising methods for CO₂ capture and storage (CCS) but the operating costs—mainly due to the need for oxygen production—usually lead to an obvious decrease in power generation efficiency. An “oxy-enrich combustion” process was proposed in this study to improve the efficiency of the oxy-fuel combustion process. The oxidizer for oxy-enrich combustion was composed of pure oxygen, air and recycled flue gas. Thus, the CO₂ concentration in the flue gas decreased to 30–40%. The PSA (pressure swing adsorption), which has been widely used for CO₂ removal from the shifting gases of ammonia synthesis in China, was applied to capture CO₂ during oxy-enrich combustion. The technological economics of oxy-enrich combustion with PSA was calculated and compared to that of oxy-fuel combustion. The results indicated that, compared with oxy-fuel combustion: (1) the oxy-enrich combustion has fewer capital and operating costs for the ASU (air separation unit) and the recycle fan; (2) there were fewer changes in the components of the flue gas in a furnace for oxy-enrich combustion between dry and wet flue gas circulation; and (3) as the volume ratio of air and oxygen was 2 or 3, the economics of oxy-enrich combustion with PSA were more advantageous. Full article

In this paper, an integrated gasification combined cycle conceptual design that achieves optimum energy efficiency and 82.9% heat integration between hot and cold utilities is illustrated. The integrated combined gasification cycle (IGCC) is also modeled and evaluated for the co-production of electricity, ammonia and methane for 543.13 kilo tonne per annum (KTA) of municipal solid waste (MSW). The final products are 1284.89 MW, 8731.07 kg/h of liquid ammonia at 8 °C and 32,468 kg/h of methane gas at 271 °C. The conceptual design includes advanced heat integration between syngas and hot and cold streams in all process units. The water gas shift (WGS) unit includes integration between equilibrium reactors and cold streams. The air separation unit (ASU) includes four air compressors followed by a pressure swing adsorber (PSA), which separates oxygen and nitrogen gases into separate streams. Both O₂ and N₂ gases are compressed and sent to gasifier and syngas cleaning unit, respectively. The overall design shows reliability and solved steady state equations for all process units with improvements in thermal efficiency in comparison with single cycle gasification plants. The environmental emissions for GHGs such CO₂ and SO₂ are lower due to higher overall energy efficiency. Full article