Concentrations Of Nitrogen Species Research Articles

Quantification of Major Inorganic Contaminants in a Mediterranean Coastal Lagoon with a Large Dystrophic Crisis.

In August 2021, the Mar Menor, a saltwater lagoon located in the Region of Murcia (Spain), suffered a tragic environmental episode of dystrophic crisis and anoxia. The appearance of numerous dead fish in different areas of the lagoon over the course of days put all the authorities and the population of the area on alert. This paper shows a case study of what happened in the lagoon in terms of the presence of the most common inorganic pollutants. Measurements of the concentration of nitrogen species, phosphates and main heavy metals were carried out at different sampling sites in the Mar Menor from May 2021 to November 2022. Chemical analyses were carried out for each of the species under study. These analyses provide valuable information about the dystrophic crisis caused by a classic eutrophication process that began with the excessive nutrient input into the Mar Menor. Ion chromatography and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were used as instrumentation for the quantification of these samples. The species whose values were greatly increased after the tragic episode described above were nitrates. The concentration varied significantly at the different sampling sites throughout the study. On the last sampling date, decreased concentrations of all the species were measured at each of the sampling sites, coinciding with the apparent good state of the lagoon.

Ultrasmall Cu2O@His Nanozymes with RONS Scavenging Capability for Anti-inflammatory Therapy.

High concentrations of reactive oxygen and nitrogen species (RONS) are key characteristics of inflammatory sites. Scavenging RONS at the site of inflammation is an effective therapeutic strategy. This study introduces ultrasmall Cu2O@His nanoparticles with RONS-scavenging ability for the treatment of inflammatory bowel disease (IBD) in mice. The strong coordination between the nitrogen atom in histidine (His) and copper enhances the dispersion and stability of Cu2O@His. Due to their small size and large surface area, Cu2O@His exhibits outstanding RONS-clearing ability. Importantly, Cu2O@His can target mitochondrial sites and repair damaged mitochondria. With excellent dispersion and scavenging RONS ability, Cu2O@His demonstrates good efficacy in treating mouse IBD. This work provides a new paradigm for developing nanozymes with an ultrasmall size and multiple scavenging RONS abilities.

Effect of air, O2, Ar, and N2 plasma‐activated water on mildewing activity of moldy pathogen of Gannan navel oranges

AbstractIn this study, the physicochemical properties of plasma‐activated water (PAW) prepared from air, , , and plasma and the trend of the concentration of reactive oxygen and nitrogen species (RONS) with respect to time were investigated and related to the effect of PAW on navel orange mold. The results showed that PAW had a strong lethal effect on navel orange mold and could effectively inhibit the mildewing activity of pathogenic spores. In addition, PAW is effective in reducing weight loss and decay of navel oranges during storage. This study suggests the potential application of PAW to prevent fungal infections during storage of agricultural products.

Metal-organic framework-polymer complex-derived single-atomic oxygen reduction catalyst for anion exchange membrane fuel cells

Metal-nitrogen-doped carbon (M−N−C) catalysts have emerged as highly active noble-metal-free catalysts for oxygen reduction reactions (ORR) in anion-exchange membrane fuel cells (AEMFCs). However, the performance of existing M−N−C catalysts is limited by the inaccessibility of internal M−Nx active sites and loss of nitrogen doping after the carbonization process. Here, a single-atom Co, Fe and N-doped porous carbon catalyst (CoFe-NC-PPy) were constructed using a complex of metal–organic frameworks (MOFs) and polypyrrole (PPy). As a new approach, we synthesized MOF and PPy composites by combining in situ MOF synthesis and pyrrole polymerization in a one-pot reaction. Through pyrolysis, the PPy and MOF composites demonstrated an enhanced specific surface area, a high active-site density, and a high concentration of nitrogen species in the M−N−C catalyst. These contributed to a superior ORR performance (E1/2 of 0.915 V) and high durability in alkaline media. Additionally, the CoFe-NC-PPy material studied in an AEMFC enabled high performance with a current density of 550 mA cm−2 at 0.6 V and a peak power density of 352 mW cm−2. This study suggests potential in combining polymers and MOFs in the synthesis of ORR catalysts for fuel cells.

(Invited) the Removal of Bisphenols from Wastewaters with Atmospheric Pressure Plasma

Bisphenols represent one of the most recognised harmful contaminants found in environment as a result of their extensive use for the industrial production of polycarbonate, epoxy resins, and thermal paper. They are known for their ability to act as endocrine disruptors, as well as for their potential to cause genotoxicity and cytotoxicity. 1. Although the awareness of their toxicity is high and the use of some of their representatives already limited or restricted in EU 2, they still represent a potential threat for public health. Due to their insufficient elimination with standard water treatment methods, the effluent from the wastewater treatment plants continues to be the major source of bisphenol environmental contamination. Thus, it is necessary to develop a new more efficient method.Cold atmospheric pressure plasma (CAP) is a promising technology with tremendous potential in removal of various hazardous contaminants from wastewater 3. Essentially, plasma is the fourth state of matter, created by introducing gas into a strong electrical field resulting in ionisation, dissociation, and excitation of gaseous molecules. CAP, which is produced by using air and electricity, is a source of high concentration of reactive oxygen and nitrogen species (RONS). This property makes it a highly promising, cost-effective, and environmentally-friendly method for decontamination 4.To demonstrate its potential, we investigated the application of air CAP for the removal of bisphenol A (BPA) and bisphenol S (BPS) from aqueous systems. Plasma was generated with surface barrier discharge systems, using different exposure times and discharge operating powers, which led to the formation of different plasma chemistries. Additionally, radical scavenger methanol was used to simulate environmental conditions. The highest degradation efficacies were observed at longest exposure time (480 s) and at high discharge power and was significantly affected by the presence of methanol. Moreover, radical scavenger influenced the formation of CAP generated RONS in liquid as well, resulting in lower concentrations of ˙OH, H2O2, and NO2 -. With non-target approach, we were able to identify 11 BPA and 5 BPS transformation products (TPs) and propose transformation pathways of both compounds. The toxicological examination performed with in vitro HepG2 cell model demonstrated that the mixture of transformation products formed during CAP treatment is less toxic than BPA and BPS. According to these results it was suggested that CAP is an effective and safe method for degradation of bisphenols. The European Parliament and the Council. Regulation (EU) 2020. Official Journal of the European Union.2018/840/EC. Commission Implementing Decision (EU) 2018/840 of 5 June 2018 Establishing a Watch List of Substances for Union-Wide Monitoring in the Field of Water Policy. J. Eur. Union 2018, L 141 (March 2015), 9–12.Sanito, R. C.; You, S. J.; Wang, Y. F. Degradation of Contaminants in Plasma Technology: An Overview. Hazard. Mater. 2022, 424 (PA), 127390.Dickenson A.; Morabit Y.; Hasan M. I.; Walsh J. L. Directional mass transport in an atmospheric pressure surface barrier discharge. Scientific Reports 2017, 7, 14003.

Pulsed-control plasma-activated water: An emerging technology to assist ultrasound for fresh-cut produce washing

In this study, we explored the use of plasma-activated water (PAW) in combination with ultrasound (US) for food disinfection. Our research introduces a novel approach that utilizes a pulsed-control (PC) method to modify the PAW. The resulting PCPAW exhibits significantly higher concentrations of key reactive oxygen and nitrogen species (RONS) compared to conventional PAW. The disinfection efficacy of US–PCPAW against fresh-cut lettuce was compared to that of US-PAW, US, and PCPAW. The combination of US and PCPAW was highly effective in reducing food-borne pathogens, surpassing single treatments in count reduction and minimizing cross-contamination. Furthermore, our study demonstrates that US–PCPAW effectively controls browning appearance without compromising sensory attributes. These findings suggest that PCPAW, as a novel disinfectant, can be a valuable addition to US to enhance the quality and safety of fresh-cut produce.

Effects of high wheat bran input on the performance of a biofloc system for Pacific white shrimp (Litopenaeus vannamei)

Applying an external carbohydrate source to stimulate heterotrophic bacteria growth in biofloc systems is a common practice which could be simplified by combining the carbohydrate source with the feed into one pellet. In the current study, such an approach was tested in Pacific white shrimp, Litopenaeus vannamei. Wheat bran (WB) containing non-starch polysaccharides (NSP), a hardly digestible carbohydrate, was mixed with a commercial-like shrimp diet (control; CONdiet) to create a wheat bran rich diet (WBdiet). Shrimp were fed isonitrogenously, resulting in the WBdiet group receiving equal absolute amount of nitrogen but more carbon than the CONdiet group. A digestibility trial was performed in a clear-water recirculating aquaculture system for 35 days, using 6 replicates aquaria per diet. Compared to the CONdiet, shrimp fed with the WBdiet had a reduced overall digestibility and an increased faecal carbon to nitrogen ratio (C:N ratio) from 12 to 20. Following the digestibility trial, a second experiment was performed to monitor the growth performance of the shrimp reared in biofloc systems for 42 days, using three replicate tanks per diet. The dissolved nitrogen species concentration was lower in the tanks fed the WBdiet, while the dissolved carbon concentration was similar between the diets. From a system perspective, similar amounts of nitrogen accumulated across the system compartments with both diets, with maximum 3% total nitrogen loss reached at the end of the experiment. The percentage of carbon loss per kg feed was similar between diets. Overall, diluting the CONdiet with wheat bran and feeding both diets isonitrogenously did not reduce shrimp survival and had minor effect on growth (2% reduction of the specific growth rate). Therefore, incorporating NSP-rich ingredients, such as wheat bran applied as one pellet has a potential to simplify the carbon addition management in a biofloc system.

Physicochemical Characteristics and Antimicrobial Efficacy of Plasma-Activated Water Produced by an Air-Operated Coaxial Dielectric Barrier Discharge Plasma

In this study, Plasma-Activated Water (PAW) was synthesized using a coaxial Dielectric Barrier Discharge (DBD) reactor, benefiting from the elevated capacity of air-flow-assisted DBD discharges to enhance nitrogen-based species concentration. By manipulating operational parameters, including gas flow rate, activation time, and DI water volume, we achieved significant concentrations of reactive oxygen and nitrogen species (RONS). As a result, the PAW obtained displayed pronounced physicochemical attributes: a pH of 2.06, an ORP of 275 mV, conductivity of 3 mS/cm, and TDS of 1200 mg/L. A pivotal aspect of this research was the evaluation of the reactor’s efficiency, as indicated by metrics like the specific input energy and ozone efficiency yield. The antimicrobial potential of the PAW was also assessed against pathogenic microbes, with remarkable reductions in viability for both Staphylococcus aureus and Escherichia coli (99.99%) and a more moderate decrease for Candida albicans (37%). These findings underscore the capability of coaxial DBD reactors in crafting high-quality PAW with significant antimicrobial properties, necessitating further studies to validate its broad-spectrum and safe applications.

Detection of micro-plasma-induced exosomes secretion in a fibroblast-melanoma co-culture model

BackgroundMelanoma is a highly aggressive tumor and a significant cause of skin cancer-related death. Timely diagnosis and treatment require identification of specific biomarkers in exosomes secreted by melanoma cells. In this study, label-free surface-enhanced Raman spectroscopy (SERS) method with size-matched selectivity was used to detect membrane proteins in exosomes released from a stimulated environment of fibroblasts (L929) co-cultured with melanoma cells (B16–F10). To promote normal secretion of exosomes, micro-plasma treatment was used to gently induce the co-cultured cells and slightly increase the stress level around the cells for subsequent detection using the SERS method. Results and discussionFirstly, changes in reactive oxygen species/reactive nitrogen species (ROS/RNS) concentrations in the cellular microenvironment and the viability and proliferation of healthy cells are assessed. Results showed that micro-plasma treatment increased extracellular ROS/RNS levels while modestly reducing cell proliferation without significantly affecting cell survival. Secondly, the particle size of secreted exosomes isolated from the culture medium of L929, B16–F10, and co-cultured cells with different micro-plasma treatment time did not increase significantly under single-cell conditions at short treatment time but might be changed under co-culture condition or longer treatment time. Third, for SERS signals related to membrane protein biomarkers, exosome markers CD9, CD63, and CD81 can be assigned to significant Raman shifts in the range of 943–1030 and 1304-1561 cm-1, while the characteristics SERS peaks of L929 and B16–F10 cells are most likely located at 1394/1404, 1271 and 1592 cm-1 respectively. Significance and noveltyTherefore, this micro-plasma-induced co-culture model provides a promising preclinical approach to understand the diagnostic potential of exosomes secreted by cutaneous melanoma/fibroblasts. Furthermore, the label-free SERS method with size-matched selectivity provides a novel approach to screen biomarkers in exosomes secreted by melanoma cells, aiming to reduce the use of labeling reagents and the processing time traditionally required.

Comparison of plasma-activated water and free chlorine in disinfecting Escherichia coli O157:H7- and Salmonella Typhimurium-inoculated blueberry, cherry tomato, fresh-cut lettuce, and baby spinach

The concentration of reactive oxygen and nitrogen species (RONS) in plasma-activated water (PAW) can be increased by increasing the input power, discharge voltage, and discharge time under a constant discharge frequency. However, knowledge regarding RONS concentration prepared under different discharge frequencies is lacking. This study investigated how decreasing the discharge frequency affects the chemical and physical properties of PAW. The highest plasma output efficiency (57%) was observed when the discharge frequency was decreased to 200 Hz, resulting in highest concentrations of hydrogen peroxide (675 μM) and nitrate (32 mg/L), as well as highest oxidation-reduction potential (547 mV) and conductivity (870 μs/cm). Fresh-cut lettuce, baby spinach, blueberry, and cherry tomato inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium were washed with 200 Hz-PAW and 10 ppm free chlorine (FC) for 1–2 min. The pathogens on the produce were inactivated by 1.8–2.5 log CFU/g using PAW, which was higher than that achieved using FC. The residual pathogens were 1.5–3.1 log CFU/mL in PAW washing water, whereas in FC water, they were inactivated below the detection limit (2 CFU/mL). Thus, decreasing the discharge frequency can increase plasma output efficiency to improve PAW properties and confirms that PAW is limited at controlling pathogen cross-contamination.

Assessment of microbial species inactivation and purification of sewage by a gas–liquid diaphragm discharge plasma

The presence of bacteria and viruses in water has caused many large-scale water disease outbreaks. Cold atmospheric plasma has received much attention as an emerging non-thermal purification technology capable of eliminating micro-organisms, non-ferrous fuels, and heavy metals from water. In this study, a novel gas–liquid diaphragm discharge device that generates air plasma driven by a sinusoidal AC power supply was designed, and its sterilizing effect was investigated. First, the concentrations of reactive oxygen and nitrogen species in the diaphragm discharge were characterized, and the physicochemical properties of activated water were explored. Next, experiments on the inactivation of Pseudomonas aeruginosa were carried out using the device. Finally, pond sewage was treated with the device, and the diversity of micro-organisms in the water was analyzed using 16S rRNA assays to further investigate its applicability. The results showed that the species and quantities of micro-organisms in the water significantly reduced after discharge treatment, with the most significant changes occurring in the Bacillus and Firmicutes species. Thus, this study provides an alternative method for microbial inactivation in sewage treatment.

Enhanced nitrate removal by alcohol-involved nitrate photolysis-induced advanced reduction process

Organic radical-based advanced reduction processes (ARPs) are garnering increasing attention for pollutant removal. However, there have been few reports on the use of organics other than formic acid in constructing ARPs. This study successfully developed a novel alcohol-involved ARP induced by nitrate photolysis and investigated its performance in nitrate removal using various alcohols (UV/NO3–/alcohol). Five alcohols, namely methanol, ethanol, n-propanol, 1,3-propanediol, and glycerol, significantly enhanced nitrate removal by at least 30%. While the photolytic removal of nitrate was 20% higher under basic conditions (pH 10) compared to pH 3 and pH 7, the efficiency of nitrate removal in the UV/NO3–/alcohol system was nearly independent of the initial pH (p greater than 0.05). However, in general, the basic condition (pH 10) promoted total nitrogen (TN) removal and reduced the residual amount of organic nitrogen in the effluent for all five alcohols. Methanol and ethanol exhibited similar performance in the UV/NO3–/alcohol systems, showing improved nitrate and TN removal compared to the other three alcohols containing a 3-carbon chain under basic condition (pH 10). Among the alcohols, UV/NO3–/glycerol resulted in the highest production of ammonia, approximately five times that formed in the UV/NO3–/methanol system. The stoichiometry of the nitrate-to-alcohol molar ratio in the UV/NO3–/alcohol systems was investigated and determined as 0.5 at an initial pH of 10 based on the analysis of nitrate removal efficiency and residual concentration of various nitrogen species. Dissolved oxygen did not significantly affect the NO3– removal and conversion in all five UV/NO3–/alcohol systems and cosolutes generally inhibited the nitrate reduction. The outcome of present study expands the alternative organic additives of ARPs to alcohols and demonstrates the potential effectiveness of the ARP as a viable approach for the reductive removal of pollutants.

Molecular dynamics simulation of the effect of AQP1 on the transmembrane transport of plasma RONS across cancer cell membranes

In the cold atmospheric plasma (CAP)-assisted cancer treatment, the increase in the concentration of reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced by CAP is believed to be related to the overexpression of aquaporins (AQPs) on cancer cell membranes. In this paper, using classical molecular dynamics simulations, the transmembrane behavior of RNS and ROS on a pure phospholipid bilayer or a AQP1-phospholipid bilayer model was studied. The research shows that hydrophobic RNS tend to be transported through the bilayer of phospholipids. The overexpression of AQP1 can significantly improve the transmembrane efficiency of hydrophilic ROS. Our simulation fills the gap in the research for RNS-related molecular simulation and provides guidance for the precise targeting of cancer cells in CAP therapy.

Overview of the Potential Beneficial Effects of Carotenoids on Consumer Health and Well-Being.

Well-known experimental research demonstrates that oxidative stress is the leading cause of the onset and progression of major human health disorders such as cardiovascular, neurological, metabolic, and cancer diseases. A high concentration of reactive oxygen species (ROS) and nitrogen species leads to damage of proteins, lipids, and DNA associated with susceptibility to chronic human degenerative disorders. Biological and pharmaceutical investigations have recently focused on exploring both oxidative stress and its defense mechanisms to manage health disorders. Therefore, in recent years there has been considerable interest in bioactive food plant compounds as naturally occurring antioxidant sources able to prevent, reverse, and/or reduce susceptibility to chronic disease. To contribute to this research aim, herein, we reviewed the beneficial effects of carotenoids on human health. Carotenoids are bioactive compounds widely existing in natural fruits and vegetables. Increasing research has confirmed that carotenoids have various biological activities, such as antioxidant, anti-tumor, anti-diabetic, anti-aging, and anti-inflammatory activities. This paper presents an overview of the latest research progress on the biochemistry and preventative and therapeutic benefits of carotenoids, particularly lycopene, in promoting human health. This review could be a starting point for improving the research and investigation of carotenoids as possible ingredients of functional health foods and nutraceuticals in the fields of healthy products, cosmetics, medicine, and the chemical industry.

Cooling enhancement for light-emitting diode using plasma-activated water

We exploit the two-phase heat transfer enhancement using plasma-activated water for application in LED cooling. Within the steady-state LED temperature 80 °C ≤TLED≤ 110 °C, up to 73% increase in heat transfer coefficient can be achieved by replacing deionized water with plasma-activated water; concomitantly, we observe up to 14% increase in illuminance. This enhancement can be attributed to the presence of reactive oxygen and nitrogen species in the plasma-activated water that reduces surface tension, and, quite unexpectedly, minimizes the oxidation of the copper (heat source) surface. Specifically, the lower surface tension of plasma-activated water can lead to smaller vapor bubbles as well as reduction in their residence times on the heated surface. On the other hand, by increasing the electrical conductivity of plasma-activated water, i.e., higher concentrations of reactive oxygen and nitrogen species, we observe significant reductions in surface oxidation on the copper (heat source) surface. Peculiarly, unlike the copper surface oxidized by deionized water, for the plasma-activated water, we observe isolated oxidized islands that consist of nanosphere structures; these islands are hydrophobic and can lead to significantly shorter residence times of vapor bubbles. Since plasma-activated water can be produced easily via the corona discharge plasma, these promising results highlight its potential to be used in two-phase cooling systems.

Vascular Redox Signaling, Endothelial Nitric Oxide Synthase Uncoupling, and Endothelial Dysfunction in the Setting of Transportation Noise Exposure or Chronic Treatment with Organic Nitrates.

Significance: Cardiovascular disease and drug-induced health side effects are frequently associated with-or even caused by-an imbalance between the concentrations of reactive oxygen and nitrogen species (RONS) and antioxidants, respectively, determining the metabolism of these harmful oxidants. Recent Advances: According to the "kindling radical" hypothesis, the initial formation of RONS may further trigger the additional activation of RONS formation under certain pathological conditions. The present review specifically focuses on a dysfunctional, uncoupled endothelial nitric oxide synthase (eNOS) caused by RONS in the setting of transportation noise exposure or chronic treatment with organic nitrates, especially nitroglycerin (GTN). We further describe the various "redox switches" that are proposed to be involved in the uncoupling process of eNOS. Critical Issues: In particular, the oxidative depletion of tetrahydrobiopterin and S-glutathionylation of the eNOS reductase domain are highlighted as major pathways for eNOS uncoupling upon noise exposure or GTN treatment. In addition, oxidative disruption of the eNOS dimer, inhibitory phosphorylation of eNOS at the threonine or tyrosine residues, redox-triggered accumulation of asymmetric dimethylarginine, and l-arginine deficiency are discussed as alternative mechanisms of eNOS uncoupling. Future Directions: The clinical consequences of eNOS dysfunction due to uncoupling on cardiovascular disease are summarized also, providing a template for future clinical studies on endothelial dysfunction caused by pharmacological or environmental risk factors.

Reduced serum concentrations of reactive oxygen and nitrogen species following strenuous exercise in the heat are not associ-ated with an upregulation in serum antioxidative capacity

Introduction: Reactive oxygen and nitrogen species (RONS) are produced as a response to exercise and play a part in guiding the adaptive response to physical training. Exercise in the heat has been shown to further increase accumulation of RONS in systemic circulation; however, a high anti-oxidative response or heat acclimatization mechanisms could attenuate this response. In a previous study, we found reduced RONS concentrations in trained athletes following strenuous cycling in the heat. Therefore, this secondary analysis assessed whether these reduced RONS serum con-centrations are induced by an increased serum antioxidant capacity. Methods: Twelve male cyclists (V̇O2peak: 60 ± 4 ml ∙ kg-1 ∙ min-1) completed a 60-minute constant workload trial (55% peak power output, ambient temperature 30.4 ± 0.6°C) with and without ice vest in a randomized order. The core body temperature (Tcore) was measured by an ingestible capsule. Blood samples were col-lected before and after each trial to determine superoxide dismutase (SOD) and catalase (CAT) activity, total antioxidant capacity (TAC) and RONS. Due to the absence of between-group dif-ferences, data of both conditions were pooled. Results: Tcore statistically increased (p < 0.001) over the experimental trials (+6.0 ± 1.6%, effect size (ES) = 5.6). Concentrations of RONS (-17.2 ± 15.5%, p < 0.001, ES = 1.0) and TAC (-8.9 ± 22.9%, p = 0.04, ES = 0.7) statistically decreased, while the activity of CAT (+15.5 ± 84.0%, p = 0.90, ES = 0.04) and SOD (+9.2 ± 58.7%, p = 0.98, ES = 0.01) remained un-changed. Conclusions: Reduced serum RONS concentrations after strenuous cycling in the heat were not associated with upregulation of serum antioxidant capacity in trained athletes. The prooxidant-antioxidant balance may rather be regulated at a myocellular level and should be further assessed in future studies.

Precise Control of Glioma Cell Apoptosis Induced by Micro-Plasma-Activated Water (μ-PAW).

To verify the existence of plasma with the potential to kill tumor cells, this paper designed a novel helium (He) micro-plasma jet array device and detected the concentration of typical long-lived reactive oxygen and nitrogen species (RONS) with oxidative activity generated by it. The paper described a new He micro-plasma jet array device consisting of nine flexible quartz capillaries with an inner diameter of 75 μm arranged in a 3 × 3 array. Sterilized ultrapure water (up water) was first treated with the He micro-plasma jet array device to activate it to form enriched RONS micro-plasma-activated water (μ-PAW), and then μ-PAW was added to the cell culture medium (with cells) to observe the proliferation of human glioma cells. The concentration of long-lived RONS, such as nitrate (NO3-), was detected according to Beer-Lambert's law in combination with UV spectrophotometry as well as a color development method. The MTT Cell Proliferation and Cytotoxicity Assay Kit combined with the Hoechst Staining Kit were used to assess the proliferation status of the cells. The results showed that the range of RONS concentration variation could be controlled in the order of micromoles (µmol), while plasma-induced tumor cell death is apoptosis that does not affect the surrounding environment.

Catalytic Properties of High Nitrogen Content Carbonaceous Materials.

The influence of structural modifications on the catalytic activity of carbon materials is poorly understood. A collection of carbonaceous materials with different pore networks and high nitrogen content was characterized and used to catalyze four reactions to deduce structure-activity relationships. The CO2 cycloaddition and Knoevenagel reaction depend on Lewis basic sites (electron-rich nitrogen species). The absence of large conjugated carbon domains resulting from the introduction of large amounts of nitrogen in the carbon network is responsible for poor redox activity, as observed through the catalytic reduction of nitrobenzene with hydrazine and the catalytic oxidation of 3,3',5,5'-tetramethylbenzidine using hydroperoxide. The material with the highest activity towards Lewis acid catalysis (in the hydrolysis of (dimethoxymethyl)benzene to benzaldehyde) is the most effective for small molecule activation and presents the highest concentration of electron-poor nitrogen species.

Long-term declines in atmospheric nitrogen and sulfur deposition reduce critical loads exceedances at multiple Canadian rural sites, 2000–2018

Abstract. Daily air concentrations of inorganic nitrogen (N) species, including gaseous HNO3 and particulate-bound (p)NH4+ and pNO3-, and sulfur (S) species, including SO2 and pSO42-, and precipitation concentrations of NO3-, NH4+, and SO42-, have been routinely monitored by the Canadian Air and Precipitation Monitoring Network (CAPMoN) since 1983. Data at 15 rural sites from 2000–2018 were used to estimate dry and wet N and S deposition fluxes, which were then used to explore their spatiotemporal trends and assess ecosystem damage through a retrospective analysis of critical loads (CLs) exceedances. Total (dry + wet) N deposition ranged from 1.7–9.5 kgNha-1yr-1 among the 15 sites, though dry deposition of NH3 and some oxidized N species were not included due to lack of monitoring data. Based on additional N measurements in 2010 at one of the sites, annual total N deposition may be underestimated by up to 32 %. Total N deposition was dominated by wet NO3- and wet NH4+ deposition, which together comprised 71 %–95 %. Contributions to dry N deposition were 40 %–74 % by HNO3, 11 %–40 % by pNH4+, and 5 %–25 % by pNO3-. Total S deposition ranged from 1.3–8.5 kgSha-1yr-1 and was dominated by wet deposition of SO42- and dry deposition of SO2. Relative percentages of wet and dry S deposition were 45 %–89 % and 11 %–55 %, respectively. Acidic ion fluxes were greatest in southeastern Canada and were comparable among the west coast, prairie, remote, and eastern Canadian sites. Oxidized N (dry HNO3, dry pNO3-, wet NO3-) deposition was greater than that of reduced N (dry pNH4+, wet NH4+) in the early 2000s. In 2014–2018, reduced N deposition surpassed that of oxidized N in southeastern Canada. Total N and S deposition decreased significantly at a rate of −0.03 to −0.25 kgNha-1yr-1 (−1.1 % yr−1 to −3.3 % yr−1) and −0.08 to −0.66 kgSha-1yr-1 (−3.5 % yr−1 to −6.6 % yr−1), respectively, among the sites. The weak declining trend in total N deposition at the west coast site was consistent with the slower decline in NOx emissions in western Canada. Reductions in total N deposition were driven by its oxidized form as trends in reduced N were non-significant. As a result, reduced N contributions to total N deposition increased on average from 42 % in 2000–2004 to 53 % in 2014–2018. Anthropogenic NOx and SO2 emissions reductions in both eastern Canada and eastern US were highly effective in reducing total oxidized N and total S deposition, respectively, in eastern Canada. Acidic deposition exceeded terrestrial CL at 5 of the 14 sites and aquatic CL at 2 of the 5 sites in the early 2000s. However, exceedances have been trending downwards and acidic deposition fluxes were mostly near or below CL after 2012 for the subset of sites assessed, which support recovery from historical acidification. Further assessments of CL exceedances are required in other Canadian regions susceptible to acidification and affected by elevated or increasing N and S emissions.