You are currently viewing a new version of our website. To view the old version click .
  • Tracked forImpact Factor
  • 8.4CiteScore
  • 25 daysTime to First Decision

Oxygen

Oxygen is an international, peer-reviewed, open access journal on the whole field of oxygen research published quarterly online by MDPI.

All Articles (129)

Photosensitized excitation of molecular oxygen generates singlet oxygen, a reactive oxygen species that has been studied in biological systems, synthetic methods and in aquatic ecosystems. The reaction of singlet oxygen with tertiary amines is important because they are widely used as electron donors in photochemical reactions. Herein we studied the reaction of singlet oxygen with multiple tertiary amines including ethylenediamine tetraacetic acid (EDTA), triethanolamine (TEOA) and triethylamine (TEA). Singlet oxygen was generated using the photosensitizers methylene blue or chlorin e6 and red light with output at 660 nm. TEOA and TEA generated more hydrogen peroxide (H2O2), the stable end product, than EDTA at all pH values tested and regardless of the photosensitizer used. Both histidine and imidazole scavenged singlet oxygen and decreased H2O2 yield. The extent of histidine scavenging was pH-dependent for the combination of methylene blue and EDTA but not for TEOA or TEA. The combination of chlorin e6 and EDTA generated less H2O2 because both contain multiple negative charges that limit their interaction. Multiple tertiary amines that are used as biochemical buffers produced similar quantities of H2O2 as EDTA, TEOA and TEA. However, these sulfonic acid-containing tertiary amines did not function as electron donors in a benzoquinone photoreduction assay.

22 October 2025

pH-dependent generation of H2O2 by MB, red light and tertiary amines. Reactions (100 μL) contained 5 μM MB and 5 mM tertiary amine in 10 mM PB of varying pH and were irradiated for 5 min. Aliquots (20 μL) were combined with 10 mM PB pH 7.4, 0.5 mM TMB and 0.5 μM HRP (100 μL total). Reactions were quenched with 100 μL 1 M HCl and absorbance measured at 450 nm. [H2O2] was determined from a H2O2 standard curve. These data are the average of three independent experiments performed in duplicate.

Monitoring of Nutrient Removal in Swine Effluents Using Sequential Reactors with Oxygen Control

  • Sedolfo Carrasquero-Ferrer,
  • Gabriel Vaca-Suárez and
  • Grace Viteri-Guzmán
  • + 1 author

Swine effluents require effective treatment due to their high pollutant load, particularly nitrogen and phosphorus, which can cause eutrophication of water bodies. This study focused on monitoring nutrient removal in a sequential biological reactor through online measurements of parameters such as dissolved oxygen (DO), pH, oxidation-reduction potential (ORP), and total alkalinity during the treatment of effluents from a pig slaughterhouse. A laboratory-scale reactor was used, operated with timer switches in an anaerobic–aerobic–anoxic sequence, a sludge retention time (SRT) of 25 days, and an operational cycle time of 16 h. The reactor demonstrated notable efficiency in contaminant removal, with an average organic matter removal of 87.1% measured as chemical oxygen demand (COD) and 95.5% as biochemical oxygen demand (BOD). Regarding nitrogen and phosphorus removal, a 69.4% reduction in total nitrogen (TN) and a 53.2% reduction in total phosphorus (TP) were observed. The pH, ORP, and DO profiles showed a clear correlation with the nutrient removal processes, allowing optimization of the phase durations in the reactor to enhance treatment efficiency.

16 October 2025

Schematic Diagram of the Sequential Biological Reactor Used.

Chronic kidney disease is closely associated with an increased risk of cardiovascular disease. Although kidney transplantation represents the treatment of choice for patients with end-stage chronic kidney disease, it is also linked to significant cardiovascular risk. This study aimed to evaluate the relationship between cardiovascular pathology and oxidative status in kidney transplant recipients, while also assessing the influence of disease etiology and humoral immune response on oxidative imbalance. A cross-sectional analysis was conducted in individuals with advanced chronic kidney disease (n = 36) and kidney transplant recipients (n = 40). A total of 18 healthy subjects were included. The enzymatic activities of xanthine oxidase, superoxide dismutase, and glutathione peroxidase, and levels of lipid peroxidation products, oxidized glutathione, and reduced glutathione were measured using spectrophotometry in plasma and mononuclear and polymorphonuclear leukocytes isolated using Ficoll density gradients. Individual oxidative status was evaluated using OXYSCORE. Kidney transplantation was associated with a higher incidence of cardiovascular disease (p < 0.01) and increased levels of both prooxidant (p < 0.01) and antioxidant parameters (p < 0.01). Elevated OXYSCORE values were observed particularly in patients with nephroangiosclerosis, diabetic kidney disease, polycystic kidney disease (p < 0.05), and cardiovascular comorbidities (p < 0.001). Additionally, the presence of anti-graft antibodies correlated with higher oxidative scores. These findings suggest that OXYSCORE may serve as a potential indicator of cardiovascular damage in kidney transplant recipients.

16 October 2025

CVD incidence based on the etiology. (a) CVD, (b) ischemic cardiopathy, (c) ACVA, (d) vasculopathy, and (e) CCI incidence in HS, ACKD, and transplanted patients with nephroangiosclerosis, diabetic nephropathy, polycystic kidney disease, interstitial nephropathy, and glomerulopathy. CVD, cardiovascular disease; ACVA, acute cerebrovascular accident; CCI, chronic cardiac insufficiency; HS, healthy subjects; ACKD, advanced chronic kidney disease; NAS, nephroangiosclerosis; DN, diabetic nephropathy; ADPKD, autosomal dominant polycystic kidney disease; IN, interstitial nephritis; GN, glomerulonephritis. * p &lt; 0.05 vs. HS; ** p &lt; 0.01 vs. HS; *** p &lt; 0.001 vs. HS; ## p &lt; 0.01 vs. ACKD; ### p &lt; 0.001 vs. ACKD; $$$ p &lt; 0.001 vs. NAS; &amp;&amp;&amp; p &lt; 0.001 vs. DN; + p &lt; 0.05 vs. ADPKD; +++ p &lt; 0.001 vs. ADPKD; a p &lt; 0.05 vs. IN; aa p &lt; 0.01 vs. IN. Chi-squared test.

Background/Objectives: Trypanosoma evansi (T. evansi) is an etiological agent of surra, and it causes significant economic losses in livestock. Rising trypanocide resistance demands alternatives that control parasitemia while mitigating oxidative and genotoxic damage. Therefore, the present study was designed to explore both the in vivo and in silico potential of Zingiber officinale (Z. officinale) as a novel phytotherapy to counter growing resistance against conventional trypanocides. Methods: Methanolic extract of Z. officinale (MZ) was orally administered at dosages of 200 mg/kg (MZ 200), 400 mg/kg (MZ 400), and 800 mg/kg (MZ 800) on a daily basis to the experimentally infected mice and compared against treated control (TC) and untreated control (UC) groups. After the infection, different parameters such as parasitemia counts, body weight changes, and the survival of infected mice were monitored for up to 7 days post-infection, while hematobiochemical parameters, oxidative stress profiles (catalase, malondialdehyde, and superoxide dismutase), and genotoxicity in brain tissues were compared at the end of the trial. Moreover, computational tools were used to predict the affinities of key bioactive compounds with twenty-one essential proteins of T. evansi. Results: The findings showed that the administration of MZ significantly (p < 0.05) reduced parasitemia and improved the survival rates in the experimentally infected mice in a dose-dependent manner. Noteworthy, significant (p < 0.05) improvements in hematological parameters and liver enzyme profiles were also recorded in MZ-treated groups. Compared to the untreated control, MZ-treated groups showed a significant amelioration in oxidative stress and genotoxicity in brain tissue in a dose-dependent fashion. The current study’s findings suggest that MZ potentially inhibits various essential proteins of T. evansi, including adenosine transporter-1, casein kinase, leucyl-tRNA synthetase, and multidrug resistance E protein. Among its constituents, 6-Isoshogaol and 6-Gingerol showed the most stable interactions in the molecular dynamics simulation. Conclusions: MZ efficiently reduced parasitemia, oxidative stress, and genotoxicity, and increased the survival rate in infected mice, suggesting it as a promising natural trypanicidal agent.

1 September 2025

Survival probability of mice treated with MZ at 200 mg/kg, 400 mg/kg, and 800 mg/kg compared to treated and untreated controls over 7 days post-infection (DPI). Survival curves for the treated control and MZ800 groups overlapped with MZ400, as no mortality was observed in these groups. Data represent survival outcomes for n = 5 mice per group.

News & Conferences

Issues

Open for Submission

Editor's Choice

Get Alerted

Add your email address to receive forthcoming issues of this journal.

XFacebookLinkedIn
Oxygen - ISSN 2673-9801Creative Common CC BY license