Scavenging Effect Research Articles

Neuroprotective effect against amyloidogenic transthyretin aggregates - Induced cytotoxicity on human neuroblastoma cell by phenolic-rich Centella asiatica extract

Transthyretin (ATTR) amyloidosis is a progressive and life-threatening neurodegenerative disease caused by aggregation of the plasma transport protein, transthyretin, for which treatment is rare and cure unavailable. Centella asiatica is a small edible herb with a long history of neurological application in ethnomedicine. This work investigated whether hydrophilic extract of C. asiatica (CAB) could suppress the toxic effects of transthyretin amyloid aggregate (TTRa) in cell model derived from the same in vivo target. TTRa was prepared via thermal-induced aggregation. Chemical cross-linking and Tricine-SDS-PAGE, Thioflavin-T fluorescence, and TEM analyses confirmed that TTRa matched the profile of TTRL55P nonfibrillar amyloid aggregates. PrestoBlue cell viability assay revealed that exposure of IMR-32 human neuroblastoma cells to TTRa (2–8 μM) resulted in significant cytotoxicity. Conversely, exposure of IMR-32 cells to CAB did not adversely affect their viability. In addition, when IMR-32 cells were co-treated with TTRa and varied concentrations of CAB, the toxic effect of TTRa was significantly (p < 0.01) inhibited dose-dependently. The extract was found to possess potent radical scavenging effects, and quantitative RP-HPLC analysis showed that asiaticoside and phenolics were its main components. The cytoprotective effect against TTRa, antioxidant property, and good safety profile collectively suggest that CAB could be applied in the development of nutraceuticals or therapeutics against transthyretin amyloidosis.

Development of over 30-years of high spatiotemporal resolution air pollution models and surfaces for California

California’s diverse geography and meteorological conditions necessitate models capturing fine-grained patterns of air pollution distribution. This study presents the development of high-resolution (100 m) daily land use regression (LUR) models spanning 1989–2021 for nitrogen dioxide (NO2), fine particulate matter (PM2.5), and ozone (O3) across California. These machine learning LUR algorithms integrated comprehensive data sources, including traffic, land use, land cover, meteorological conditions, vegetation dynamics, and satellite data. The modeling process incorporated historical air quality observations utilizing continuous regulatory, fixed site saturation, and Google Streetcar mobile monitoring data. The model performance (adjusted R2) for NO2, PM2.5, and O3 was 84 %, 65 %, and 92 %, respectively.Over the years, NO2 concentrations showed a consistent decline, attributed to regulatory efforts and reduced human activities on weekends. Traffic density and weather conditions significantly influenced NO2 levels. PM2.5 concentrations also decreased over time, influenced by aerosol optical depth (AOD), traffic density, weather, and land use patterns, such as developed open spaces and vegetation. Industrial activities and residential areas contributed to higher PM2.5 concentrations. O3 concentrations exhibited no significant annual trend, with higher levels observed on weekends and lower levels associated with traffic density due to the scavenger effect. Weather conditions and land use, such as commercial areas and water bodies, influenced O3 concentrations.To extend the prediction of daily NO2, PM2.5, and O3 to 1989, models were developed for predictors such as daily road traffic, normalized difference vegetation index (NDVI), Ozone Monitoring Instrument (OMI)–NO2, monthly AOD, and OMI-O3. These models enabled effective estimation for any period with known daily weather conditions.Longitudinal analysis revealed a consistent NO2 decline, regulatory-driven PM2.5 decreases countered by wildfire impacts, and spatially variable O3 concentrations with no long-term trend. This study enhances understanding of air pollution trends, aiding in identifying lifetime exposure for statewide populations and supporting informed policy decisions and environmental justice advocacy.

Chemical composition, antioxidant and antimicrobial activities of Lepechinia rufocampii Epling &amp; Mathias essential oil from the highlands of Ecuador

The chemical composition, antioxidant andantimicrobial activities of the essential oil from leaves and flowers of Lepechinia rufocampii Epling &amp; Mathias were studied. GC-FID and GC-MS analyses allowed the identification and quantification of 122 constituents, representing 98.7% of the essential oil. Aliphatic compounds, mainly methyl ketones (62.4%) and sesquiterpene hydrocarbons (19.5%) were found to be the most abundant compounds, while oxygenated monoterpenes were the minor. The most abundant compounds were undecan-2-one (34.6%), nonan-2-one (21.1%), and (E)-caryophyllene (8.3%). Antioxidant activity was examined using DPPH, ABTS, and FRAP assays. The essential oil had a low scavenging effect and it showed ferric reducing activity. Antimicrobial activity of the essential oil was observed against pathogenic bacteria and a pathogenic yeast. The essential oil showed very good activity against Staphylococcus aureus, Escherichia coli and Salmonella enterica serovar, but low activities against Pseudomonas aeruginosa and Candida albicans. The MIC value of the essential oil varied from 1.04-33.05 μL/mL, with the lowest for Salmonella enterica serovar.

Determination of Superoxide Radical Scavenging Activity and Total Antioxidant Capacity by Modified DMPD Method

Among the reactive oxygen species, Superoxide radicals can produce dangerous species that cause lipid peroxidation. Therefore, the determination and scavenging of superoxide radicals is critical. Our study is based on the interaction of the superoxide radical produced from the β-Nicotinamide adenine dinucleotide reduced disodium salt hydrate and phenazine methosulfate (NADH-PMS) system with N, N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) to form the pink colored DMPD-quinone (DMPDQ) radical. In the presence of scavengers with superoxide radical scavenging activity (antioxidants, herbal teas) the color intensity decreases due to reduced DMPDQ radical production. The absorbance of the colored reference solution and the sample solution containing the radical scavenger was measured at 552 nm. The difference in absorbance (ΔA) between the reference solution and the sample solution was found. ΔA is proportional to the scavenger concentration. In the study, the superoxide radical scavenging effect of trolox (TR) and different AOXs was investigated. The superoxide radical scavenging effect of three different herbal tea infusion solutions was measured with this method. From the graph drawn between herbal tea concentrations and percentage inhibition values, 50% inhibition (EC50) values of herbal teas were found. EC50 method values were compared with the EC50 values of the nitroblue tetrazolium (NBT) and the 2,2'-azino-bis(3-etilbenzotiyazolin-6-sülfonik asit (ABTS) method. In addition, ABTS, cupric reducing antioxidant capacity (CUPRAC), and this study total antioxidant capacity (TAC) values of herbal tea infusions were calculated and compared.

Excessive hydrogen sulfide-induced activation of NMDA receptors in the colon participates in anxiety- and compulsive-like behaviors in a rodent model of hemorrhagic shock and resuscitation

ObjectiveHemorrhagic shock and resuscitation (HSR) cause inflammatory responses in the gastrointestinal tract and is associated with substantial morbidity and mortality rates. Hydrogen sulfide (H2S), a gasotransmitter with pleiotropic activity, exhibits anti-inflammatory benefits at physiological levels. However, deleterious effects are observed when its concentration increases. In this investigation, we employed a mouse model of HSR to examine the effects of an H2S scavenger on the gastrointestinal tract and brain, with emphasis on N-Methyl-d-Aspartate (NMDA) receptor function. MethodsMice were immediately administered dl-propargylglycine (PAG) intragastrically as an H2S scavenger after HSR exposure. The O-maze and buried beads tests were used to assess compulsive- and anxiety-like behaviors. Pathological changes in the intestine were evaluated at 24 and 30 days after HSR. Subsequently, at 30 days after HSR, we examined electrophysiological and pathological changes in the amygdala. ResultsWithin 24 h of HSR exposure, animals treated with PAG showed significantly lower colonic injury. Additionally, compared to the HSR-treated mice 30 days after HSR, the PAG-treated mice displayed reduced buried beads, increased open-arm time, lower blood levels of Diamine Oxidase (DAO) and considerably improved ZO-1 intensity, a stronger association between the delta rhythm phase and beta activity amplitude, and lower neuroinflammatory response in the amygdala. MK-801, an NMDA receptor inhibitor, significantly reversed H2S-induced intestinal and cerebral injury. ConclusionThis experimental data suggests that H2S-induced excessive activation of NMDA receptors contributes to anxiety- and compulsive-like behaviors caused by HSR.

Pollution trends in a protected fluvial landscape located in a highly industrialized Ostrava urban agglomeration; Rezavka Nature Reserve, Czech Republic

Abandoned meanders and former river channels represent important depositional units of fluvial river systems, making them suitable sedimentary archives for assessing pollution trends. The objective of this study is to provide insight into temporal trends and spatial variability in pollution levels in the selected fluvial elements (an abandoned meander, a former river channel, and a semi-open meander) within the Rezavka Nature Reserve (part of the Poodří protected landscape area) along the Odra River and Mlýnka stream, located in the heavily polluted Ostrava urban agglomeration (Czech Republic). Initial stages of the abandoned meander evolution were characterised by high sediment accumulation rates and decelerated over time, while more regular sediment supply continued in sites close to the semi-open meander of the Mlýnka stream. Pollutants were effectively captured by abandoned meanders with fine-grained infill, while the coarser-grained infill of the former channel was less effective pollutant scavenger. A time frame for deposition was assigned using vertical trends in 137Cs mass activity and selected organic pollutants. The sedimentary record, covering the last ~ 70 years, reveals a distinct vertical pollution trend that reflects industrial development. Pollution levels have increased since the 1950s and will remain high at the end of the 20th century. The depth pattern of heavy metals, as well as their enrichment factors, shows an upward increase. Levels of persistent organic pollutants are typically low or under the limit of detection in the deepest strata, gradually or sharply rising upward.

Acrolein scavengers and detoxification: From high-throughput screening of flavonoids to mechanistic study of epigallocatechin gallate

Acrolein (ACR) is a widespread, highly toxic substance that poses significant health risks. Flavonoids have been recognized as effective ACR scavengers, offering a possible way to reduce these risks. However, the lack of specific high-throughput screening methods has limited the identification of ACR scavengers, and their actual detoxifying capacity on ACR remains unknown. To address this, we developed a high-throughput screening platform to assess the ACR scavenging capacity of 322 flavonoids. Our results showed that 80.7 % of the flavonoids could scavenge ACR, but only 34.4 % exhibited detoxifying effects in an ACR-injured QSG7701 cell model. Some flavonoids even increased toxicity. Structure-activity relationship (SAR) analysis indicated that galloyl and pyrogallol units enhance scavenging but worsen ACR-induced cytotoxicity. Further investigation revealed that epigallocatechin gallate (EGCG) could exacerbate ACR-induced redox disorder, leading to cell apoptosis. Our findings provide crucial data on the scavenging and detoxifying capacities of 322 flavonoids, highlighting that ACR scavengers might not mitigate ACR-induced toxicity and could pose additional safety risks.

DEGRADATION KINETICS OF TEXTILE AZO DYE REACTIVE ORANGE-16 BY GAMMA IRRADIATION

Gamma radiation have become attention since their high potential for degrading compounds, especially organic pollutants. In this research, gamma radiation was studied for degrading the Reactive Orange-16 (RO-16) dye, a toxic and carcinogenic pollutant. The radiolytic degradation process was studied in a batch reactor with a gamma-ray dose rate of 2.930 kGy/h. The effect of experimental variable such as initial peroxide concentration, initial pH, initial dye concentration, and addition of inorganic anion were studied. The highest degradation rates were achieved at a peroxide concentration ranging from 2 to 4 mM. In contrast, the higher peroxide concentration indicated the slower degradation process caused by the scavenging effect of the peroxide. Degradation of 88% RO-16 dye with 0.1 mM initial concentration, was achieved at 2.0 kGy irradiation dose and 97.4% degradation in the presence of 4 mM peroxide. The dose constant (d) for those degradation processes was 1.0657 kGy-1 and 1.8420 kGy-1 respectively. The degradation was more efficient in acid pH. The degradation process increased with lower initial dye concentrations. The degradation of RO-16 dye by gamma-ray was inhibited by the presence of inorganic anions in the following sequence: NO3-→ CO32− → HCO3− → CH3COO-→ Cl-.

Investigation of Cytotoxic Effects of Tragopogon reticulatus Against HepG2 and MCF-7 Cell Lines and Antioxidant, Antimicrobial Effects Against Some Microorganisms

Plants have been used for various purposes throughout history. This subject has received increasing attention in the field of traditional medicine in recent years. Tragopogon reticulatus, as a forage grass plant in turkey, is a species that stands out with rich vitamin and mineral content. The aim of this study was to investigate the antimicrobial, antioxidant, and cytotoxic activities of T. reticulatus. Two separate extracts were prepared at different concentrations using hexane and methanol solvents obtained from the T. reticulatus plant, and cytotoxic activity was evaluated by the MTT Assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method on human liver cancer (HepG2) and human breast cancer (MCF7) cell lines. The antioxidant activity of the extracts obtained from methanol and hexane was determined by the DPPH (2,2-diphenyl 1-picrylhydrazyl) radical scavenging capacity method. Antimicrobial activity was evaluated by the disk diffusion method, and bacteria such as Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Bacillus megaterium, and Candida albicans fungus were used in the study. The hexane extract obtained from the T. reticulatus plant showed a high cytotoxic activity of 44% in the MCF7 cell line, while it showed a 51% dead cell count in the HepG2 cell line. When the antioxidant results were evaluated, it was determined that the DPPH radical scavenging effect of the hexane extract exhibited the most effective activity at 19%. When the antimicrobial results were evaluated, it was determined that the concentrations prepared with hexane exhibited the most effective activity with a zone diameter of 16 mm against B. megaterium. These findings suggest that T. reticulatus plant extracts can be considered as a potential source. These results may shed light on future research into the biological effects of the plant and contribute to the development of new treatment methods.

Silk-enriched hydrogels with ROS-scavenging dendrimers for advanced wound care

This study explores the development of novel hydrogel composites for wound care, incorporating silk fibroin and reactive oxygen species (ROS)-scavenging dendrimers into a polyvinyl alcohol (PVA) matrix. Utilizing ionizing gamma radiation, we fabricated pristine PVA, silk-PVA (SPVA) binary, and dendrimer-silk-PVA (DSPVA) ternary hydrogel composites, with their composition confirmed via UV–visible absorption spectroscopy. Fourier-transform infrared (FTIR) and Raman spectroscopy analyses indicated complex interactions between the hydrogel components, enhancing their structural and biocompatible properties. Scanning electron microscopy (SEM) analysis revealed that dendrimer integration in DSPVA hydrogels significantly increased surface porosity, vital for tissue regeneration. The DSPVA hydrogels demonstrated effective ROS scavenging, reducing hydrogen peroxide (H2O2) concentrations by approximately 70 % within 24 h. In vivo wound healing studies in a diabetic mouse model showed enhanced wound closure in the DSPVA group, with a relative wound area reduction to 30 ± 4.3 % on day 10, compared to 56.5 ± 2.7 % in the control group. By the 16th day, the treated group exhibited near-complete wound contraction, markedly outperforming the control group. These findings underscore the potential of DSPVA hydrogels in diabetic wound management, combining silk fibroin's mechanical support, dendrimers' antioxidative properties, and PVA's structural benefits. Thus, DSPVA hydrogels are promising candidates for advanced wound care applications.

Terrestrial input and biological processes drive varying mineral/organic matrix-related mercury sequestration and deposition in the East Siberian Arctic Shelf

Thawing Arctic permafrost is releasing massive amounts of terrestrial mercury (Hg) into the Arctic shelf, which is expected to form a Hg sink in sediments. Here we analyzed the coupling roles of terrestrial input and biological processes in varying mineral/organic matrix-related Hg sequestration and deposition on the East Siberian Arctic shelf (ESAS), using Pearson and partial correlation analysis. Results show that the occurrence of Hg in the Laptev Sea under the Lena River-dominated input exhibits strong correlations with the organic carbon (OC) content and sediment specific surface area. This indicates that the prolonged riverine loading processes facilitate Hg sequestration by organic/mineral matrices and these land-derived mineral-OC-Hg complexes remain stable during cross-shelf transportation. By contrast, the comparative samples with coastal erosion-dominated Hg input in the western East Siberian Sea shows limited Hg complexation, primarily due to the absence of regulation by riverine processes and/or the high sedimentation rates. The correlations between Hg and OC source proxies (δ13C and lignin) indicate that these matrix-free Hg could be more readily sequestrated by the marine OC, which facilitates its deposition via the biological pump. While unexpectedly low Hg abundance in the Chukchi Sea may indicate that the effective biological scavenging of Hg sequestration could be constrained by insufficient terrestrial Hg input. Our findings of the matrix-related Hg sequestration by mineral and/or OC association in this study may shed light on the biogeochemical cycle of Hg in the Arctic aquatic regime, which could reduce the methylmercury formation in water column, and the methylation within sediments needs further exploration.

Enhancing safe and effective treatment of carbapenem-resistant Klebsiella pneumoniae with polymyxin B-loaded dendritic nanoparticles

Polymyxin B (PMB) is highly effective against Gram-negative bacterial infections, notably in targeting lipopolysaccharide (LPS), making it a vital last-resort treatment for carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. However, its clinical application is hampered by nephrotoxicity and complications arising from its positive charge. This study introduces dendritic mesoporous organosilica nanoparticles loaded with PMB (PBSi-NPs), designed to overcome these limitations. The PBSi-NPs, with an average size of 170 nm, demonstrate effective LPS scavenging, enhanced bacterial internalization, and potent bactericidal properties. Their ability to release PMB in acidic microenvironments, characteristic of bacterial infections, significantly enhances the management of severe CRKP-induced infections. Notably, PBSi-NPs exhibit reduced toxicity towards human embryonic kidney cells (HEK 293), attributed to their stimulus-responsive design. In vivo, they exhibit higher targeting of lung cells than free PMB, specifically alveolar and bronchial cells, and effectively treat severe pneumonia in a CRKP (isolated from clinical sample) induced mouse model, markedly improving survival rates. This study proposes a novel, cost-effective method for PMB delivery using PBSi-NPs, potentially broadening the scope of nanomedicine for treating critically ill CRKP-infected patients.

Mitigating CYP3A4-mediated aflatoxin toxicity with algal-derived Sodium Copper Chlorophyllin: Production and In-silico insights

The present research explores the cytotoxic mechanism of protein Cytochrome P450 (CYP3A4) with aflatoxin (AFB1), a potent carcinogen. Cytochrome P450 is an essential enzyme involved in drug metabolism, however epoxide formation due to the binding event of AFB1 leads to cell cytotoxicity. In this direction, our study elucidates the scavenging effect of algal-derived Sodium Copper Chlorophyllin (SCC) over AFB1 cytotoxicity. Cyanobacteria/ microalgae-derived SCC have garnered attention due to its diverse applications in pharmacological and food industries. This work began with the production of SCC from Spirulina and Chlorella sp. over a stipulated period of growth. Subsequently, the study delved into the interplay between SCC and the carcinogenic impact of AFB1 on the CYP3A4 enzyme. Computational studies demonstrated SCC binding and blocking mechanisms against AFB1. Our research intended to determine whether CYP3A4 can bind to SCC that, in turn, act as an interceptor for AFB1 or influence the metabolism of bound AFB1. Current results support that SCC is an effective AFB1 trap as it shows interactions with AFB1. These findings would open up new avenues in clinical biology/pharmacology to further explore the mechanisms of action of CYP3A4 with AFB1 and SCC, offering promising prospects for abating cell cytotoxicity.

Phytochemical profiles, bioactivities, and molecular docking and molecular dynamics approaches of endemic Campanula baskilensis Behçet (campanulaceae)

Campanula species have phenolic derivatives with a broad biological potential. This study aimed to investigate the chemical contents, bioactivities, and prediction of the biological effect mechanism using the molecular docking study for C. baskilensis (CB) leaf (L), root (R), and stem (S) extracts.CBL gave the highest phenolic contents as hesperidin at 7.56 mg/g extract. Total phenolic and flavonoid contents of CBS were determined as 3.12 ± 0.05 mg GAE/g and 1.11 ± 0.11 mg QE/g, respectively. CBS and CBL exhibited high DPPH• scavenging, H2O2 scavenging, AChE, BChE, carbonic anhydrase, lipase, and tyrosinase inhibition effects and demonstrated potent antimicrobial activity. The strong phenolic components of CBS and CBL extracts contributed to their biological activities. According to the molecular docking results, a high inhibition effect was observed on the inhibition activities due to the presence of hesperidin, which is the highest main component of the extracts. Additionally, docking studies were performed on hesperidin for the first time. Dynamics study showed that the interaction between the hesperidin and BChE increased stability, producing a stable complex form within 100 ns. In conclusion, C. baskilensis extracts, especially hesperidin, may be promising potential sources for neurological diseases and complementary medicine.

Characterization of carbonaceous components and PAHs on ultrafine particles in Phnom Penh, Cambodia.

This study investigated seasonal fluctuations in particulate matter (PM) concentrations, including carbon and polycyclic aromatic hydrocarbon (PAH) components, in Phnom Penh, Cambodia, focusing on ultrafine particles (UFPs or ≤ 100nm). UFP levels were notably higher during the dry season, averaging 23.73 ± 3.7µg/m3 compared to 19.64 ± 3.4µg/m3 in the wet season, attributed to increased emissions from vehicles and agricultural burning. In contrast, lower concentrations during the wet season were due to scavenging effect of rain. When compared to other Southeast Asian cities, UFP levels in Phnom Penh were significantly higher during the dry season, surpassing those in cities like Bangkok and Kuala Lumpur. Seasonal variations in carbonaceous components showed higher elemental carbon (EC) and total carbon (TC) during the dry season, with EC/TC ratios suggesting substantial influence from vehicular emissions and biomass burning. PAH analysis revealed seasonal disparities, with higher concentrations of benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF) during the wet season, whereas fluoranthene (Flu) and pyrene (Pyr) were consistently present, indicating diverse PAH sources. The Flu/(Flu + Pyr) ratios, indicative of biomass burning, were higher in the dry season. Correlations between PAHs and carbon components confirmed combustion as a significant source of PAHs, aligning with global trends. This emphasizes the need to address distinct PM sources during various season in Phnom Penh.

Insight into wet scavenging effects on sulfur and nitrogen containing organic compounds in urban Beijing

Sulfur-containing organic compounds (SOCs) and nitrogen-containing organic compounds (NOCs) play critical roles in regulating the physical and chemical properties of organic aerosols (OA), while the understanding of them remains limited. Here, the high-resolution real-time measurements of submicron aerosols were conducted in urban Beijing, mainly to investigate wet scavenging effects on the potential formation and evolution mechanism of OA, especially SOCs and NOCs. OA composition transitioned from being primarily SOCs before wet processes to NOCs after wet processes. Further molecular fragments identification suggested SOCs mainly comprised glycolic acid sulfate formed by aqueous-phase processing during the entire observation, and aromatic- and monoterpene-derived SOCs formed by photochemical processing before snowfall. NOCs species were diverse and dominated by highly oxidized amides and amino acids mainly produced by photochemical processing. This study provided an in-depth insight into the potential formation and evolution pathways of SOCs and NOCs in OA in the urban atmosphere.

Hyperbilirubinemia and retinopathy of prematurity: a retrospective cohort study.

Retinopathy of prematurity (ROP) is a vasoproliferative retinal disease in preterm infants. Oxidative stress plays a key role in the pathogenesis of ROP. Due to its antioxidant effects, bilirubin has been proposed to be protective against ROP. This study explored the association between hyperbilirubinemia and ROP. We analyzed a 10-year cohort from a neonatal intensive care unit in Milan, Italy, including 1606 infants born under 32 weeks and/or < 1500 g. Data from 1606 infants meeting specific inclusion criteria were reviewed. Eighty infants were excluded due to lack of data, 1526 were deemed eligible for analysis, and 1269 had hyperbilirubinemia requiring phototherapy. There was a higher incidence of ROP among infants with hyperbilirubinemia (13.8%) versus those without (7.8%, p<0.01). Infants with any ROP, non-severe or severe ROP, were exposed to hyperbilirubinemia for a significantly higher number of days compared with those without ROP. Each additional day of exposure increases the risk of developing any ROP by 5%, non-severe ROP by 4%, and severe ROP by 6%. However, this correlation was not observed in infants with gestational age less than 27 weeks and/or body weight less than 1000 g. Conclusion: Our data show that hyperbilirubinemia requiring phototherapy is associated with an increased risk of developing ROP. However, severe hyperbilirubinemia and ROP share many of their risk factors. Therefore, rather than being a risk factor itself, hyperbilirubinemia may be a surrogate for other risk factors for ROP. Clinical Trial Registration: NCT05806684. What is Known: • The development of retinopathy of prematurity (ROP) is influenced by several critical risk factors, including low gestational age, low birth weight, supplemental oxygen use, and increased oxidative stress. • In vitro, unconjugated bilirubin is an effective scavenger of harmful oxygen species and a reducing agent, highlighting its potential protective role against oxidative stress. What is New: • Hyperbilirubinemia requiring phototherapy was associated with an increased risk of developing ROP, but this association was not observed in the most vulnerable population of extremely preterm infants. • Every additional day of phototherapy for hyperbilirubinemia increases the risk of ROP by 5% for any ROP, 4% for non-severe ROP, and 6% for severe ROP.

Evaluating O2 : Ar, N2 : Ar, and 29,30N2 using membrane inlet mass spectrometry configured to minimize oxygen interference

AbstractMembrane inlet mass spectrometry (MIMS) provides detailed measures of dissolved 28,29,30N2, O2, and argon (Ar) for estimating important gas fluxes and concentrations in aquatic ecosystems. Previous studies demonstrated a large O2 scavenging effect while using a MIMS, where varying concentrations of O2 can affect measured N2 : Ar because O2 interacts with N2 in the ion source to produce NO+ (m/z = 30), potentially decreasing the detected current for 28,29N2 and increasing the detected current for 30N2. A common solution is to use a muffle furnace heated to 600°C with a copper reduction column to reduce the concentration of O2 to minimal levels and accurately measure 28,29,30N2. However, this solution eliminates the detection of O2 in environmental samples, which is a major benefit of using a MIMS. We questioned whether the MIMS was sensitive enough to provide accurate O2 estimates when using the furnace and whether the O2 scavenging effect was real and consistent among MIMS. We conducted four separate experiments on three different MIMS to test the O2 scavenging effect and the potential detection of O2 when using a MIMS with furnace. The furnace removed ~ 99% of O2, and O2 scavenging had little to no detectable effect on N2 : Ar and an unclear effect on 29N2 : 28N2, but increased 30N2 : 28N2. In most cases, accurate O2 data could be retrieved despite using the furnace. The need for O2 reduction may be limited to measuring accurate 30N2 : 28N2 in isotope pairing studies, but without substantial loss of MIMS measurements used to describe O2 dynamics.

Levodopa-induced dyskinesia: brain iron deposition as a new hypothesis.

Parkinson's disease (PD) is a common neurodegenerative disease in the older adults. The main pathological change in PD is the degenerative death of dopamine (DA) neurons in the midbrain substantia nigra, which causes a significant decrease in the DA content of the striatum. However, the exact etiology of this pathological change remains unclear. Genetic factors, environmental factors, aging, and oxidative stress may be involved in the degenerative death of dopaminergic neurons in PD. Pharmacological treatment using levodopa (L-DOPA) remains the main treatment for PD. Most patients with PD consuming L-DOPA for a long time usually develop levodopa-induced dyskinesia (LID) after 6.5years of use, and LID seriously affects the quality of life and increases the risk of disability. Recently, studies have revealed that cerebral iron deposition may be involved in LID development and that iron deposition has neurotoxic effects and accelerates disease onset. However, the relationship between cerebral iron deposition and LID remains unclear. Herein, we reviewed the mechanisms by which iron deposition may be associated with LID development, which are mainly related to oxidative stress, neuroinflammation, and mitochondrial and lysosomal dysfunction. Using iron as an important target, the search and development of safe and effective brain iron scavengers, and thus the alleviation and treatment of LID, has a very important scientific and clinical value, as well as a good application prospect.

A comparative study on the combustion of lean NH3/H2/air ignited by pre-chamber turbulent jet ignition modes

Internal combustion engines fueled with mixtures of hydrogen (H2) and ammonia (NH3) are potential power devices for reducing carbon emissions. To improve the ignition and combustion performance of NH3/H2, turbulent jet ignition (TJI) can be used. This study aims to investigate NH3/H2/air combustion under TJI modes at low equivalence ratios. Considering that the adoption of the scavenging system is beneficial for improving the reactivity of the pre-chamber, the effect of active TJI with scavenging is also explored. The results show that injecting 1.2 times the initial mixture volume of air is optimal for scavenging, and the scavenging effect becomes significant as the NH3 fraction increases. Using conventional active TJI and active TJI with scavenging effectively improves ignition performance and flame propagation, reducing sensitivity to the equivalence ratio compared to passive TJI mode. Although the adoption of active TJI modes improves the lean flammability limit of NH3/H2, weak flame propagation may occur in the early stage of combustion under ultra-lean conditions. Appropriately increasing the injection of auxiliary H2 can effectively improve this phenomenon.