O2 Conditions Research Articles

16α-OHE1 alleviates hypoxia-induced inflammation and myocardial damage via the activation of β2-Adrenergic receptor

ObjectiveMyocardial injuries resulting from hypoxia are a significant concern, and this study aimed to explore potential protective strategies against such damage. Specifically, we sought to investigate the cardioprotective effects of 16α-hydroxyestrone (16α-OHE1). MethodsMale Sprague‒Dawley (SD) rats were subjected to hypoxic conditions simulating high-altitude exposure at 6000 m in a low-pressure chamber for 7 days. Before and during hypoxic exposure, estradiol (E2) and various doses of 16α-OHE1 were administered for 14 days. Heart weight/body weight (HW/BW), myocardial structure, Myocardial injury indicators and inflammatory infiltration in rats were measured. H9C2 cells cultured under 5% O2 conditions received E2 and varying doses of 16α-OHE1; Cell viability, apoptosis, inflammatory infiltration, and Myocardial injury indicators were determined. Expression levels of β2AR were determined in rat hearts and H9C2 cells. The β2AR inhibitor, ICI 118,551, was employed to investigate β2AR's role in 16α-OHE1's cardioprotective effects. ResultsHypoxia led to substantial myocardial damage, evident in increased heart HW, CK-MB, cTnT, ANP, BNP, structural myocardial changes, inflammatory infiltration, and apoptosis. Pre-treatment with E2 and 16α-OHE1 significantly mitigated these adverse changes. Importantly, the protective effects of E2 and 16α-OHE1 were associated with the upregulation of β2AR expression in both rat hearts and H9C2 cells. However, inhibition of β2AR by ICI 118,551 in H9C2 cells nullified the protective effect of 16α-OHE1 on myocardium. ConclusionOur findings suggest that 16α-OHE1 can effectively reduce hypoxia-induced myocardial injury in rats through β2ARs, indicating a promising avenue for cardioprotection.

Hybrid high-performance oxygen reduction reaction Fe–N–C electrocatalyst for anion exchange membrane fuel cells

Atomically dispersed active sites and hierarchical porosity in Fe–N–C catalyst materials are essential for efficient oxygen reduction reaction (ORR) electrocatalysis and effective mass transport, respectively. However, the majority of these catalysts fail to deliver outstanding electrocatalytic activity and stumble when used as cathode materials in fuel cells. Herein, we developed a catalyst with partially transformed metallic Fe into Fe-Nx sites embedded in the carbonaceous matrix, and its excellent electrocatalytic performance is attributed to the hybrid nanoparticles and built-in Fe-Nx site structures. The optimized Fe@Fe–N–C catalyst was tested for ORR performance both ex-situ using the rotating (ring)-disk electrode technique and in an anion exchange membrane fuel cell (AEMFC). The Fe@Fe–N–C electrocatalyst exhibited remarkably enhanced ORR activity in alkaline media with a half-wave potential of 0.822 V vs. reversible hydrogen electrode (RHE) and showed the maximum power density (Pmax) of 242 mW cm−2 in an AEMFC test, surpassing the peak power density obtained from the Pt/C cathode catalyst (Pmax = 220 mW cm−2) under H2–O2 conditions. Therefore, the study provides a promising prospect for designing improved, cost-effective, and noble metal-free electrocatalysts for achieving high performance in AEMFCs.

A preventative role of nitrate for hypoxia-induced intestinal injury

BackgroundStudying effective interventions for hypoxia-induced injury is crucial, particularly in high-altitude areas. Symptoms stemming from intestinal injuries have a significant impact on the health of individuals transitioning from plains to plateau regions. This research explores the effects and mechanisms of nitrate supplementation in preventing hypoxia-induced intestinal injury. MethodsA hypoxia survival mouse model was established using 7% O2 conditions. The intervention with 4 mM sodium nitrate (NaNO3) in drinking water commenced 7 days prior to hypoxia exposure. Weight monitoring, hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), and intestinal permeability assays were employed for physiological, histological, and functional analyses. Quantitative PCR (qPCR), Western blot, and immunofluorescence were utilized to analyze the levels of tight junction (TJ) proteins and hypoxia-inducible factor 1α (Hif 1α). RNA sequencing (RNA-seq) identified nitrate's target, and chromatin immunoprecipitation (ChIP) verified the transcriptional impact of Hif 1α on TJ proteins. Villin-cre mice infected with AAV9-FLEX-EGFP-Hif 1α were used for mechanism validation. ResultsThe results demonstrated that nitrate supplementation significantly alleviated small intestinal epithelial cell necrosis, intestinal permeability, disruption of TJs, and weight loss under hypoxia. Moreover, the nitrate-triggered enhancement of TJs is mediated by Hif 1α nuclear translocation and its subsequent transcriptional function. The effect of nitrate supplementation on TJs was largely attributed to the stimulation of the EGFR/PI3K/AKT/mTOR/Hif 1α signaling pathways. ConclusionNitrate serves as a novel approach in preventing hypoxia-induced intestinal injury, acting through Hif 1α activation to promote the transcription of TJ proteins. Furthermore, our study provides new and compelling evidence for the protective effects of nitrate in hypoxic conditions, especially at high altitudes.

Impact of the hypoxic microenvironment on spermatogonial stem cells in culture.

The stem cell niche plays a crucial role in the decision to either self-renew or differentiate. Recent observations lead to the hypothesis that O2 supply by blood and local O2 tension could be key components of the testicular niche of spermatogonial stem cells (SSCs). In this study, we investigated the impact of different hypoxic conditions (3.5%, 1%, and 0.1% O2 tension) on murine and human SSCs in culture. We observed a deleterious effect of severe hypoxia (1% O2 and 0.1% O2) on the capacity of murine SSCs to form germ cell clusters when plated at low density. Severe effects on SSCs proliferation occur at an O2 tension ≤1% and hypoxia was shown to induce a slight differentiation bias under 1% and 0.1% O2 conditions. Exposure to hypoxia did not appear to change the mitochondrial mass and the potential of membrane of mitochondria in SSCs, but induced the generation of mitochondrial ROS at 3.5% and 1% O2. In 3.5% O2 conditions, the capacity of SSCs to form colonies was maintained at the level of 21% O2 at low cell density, but it was impossible to amplify and maintain stem cell number in high cell density culture. In addition, we observed that 3.5% hypoxia did not improve the maintenance and propagation of human SSCs. Finally, our data tend to show that the transcription factors HIF-1α and HIF-2α are not involved in the SSCs cell autonomous response to hypoxia.

Fabrication of gold nanoparticles supported on hollow microsphere of nanosized TS-1 for the epoxidation of propylene with H2 and O2

The TS-1 microsphere was facilely prepared via a direct spray drying of the mixture containing the nanocrystal TS-1 and mother liquor. The calcined TS-1 zeolites possess a hollow structure and numerous intercrystalline mesopores, which may facilitate the diffusion properties. Au nanoparticles were loaded on TS-1 support by utilizing a deposition–precipitation process to prepare the Au/TS-1-M catalysts for propylene epoxidation in the presence of H2 and O2 conditions. The effects of the Ti and Au loadings on the structure, porosity, morphology, and catalytic performances of the Au/TS-1 catalysts have been investigated by various techniques. Under the optimized synthesis conditions (Si/Ti molar ratio = 57, 0.49 wt% Au), a propylene conversion of 6.1 % and a PO selectivity of 91.7 % were obtained on the Au/TS-1 catalyst. A PO formation rate of 186.8 gPO·kgcat.−1·h−1 was achieved at the 20th hour.

Reduced oxygen concentrations regulate the phenotype and function of human granulosa cells in vitro and cause a diminished steroidogenic but increased inflammatory cellular reaction.

Oxygen (O2) concentrations have recently been discussed as important regulators of ovarian cells. Human IVF-derived granulosa cells (human GCs) can be maintained in vitro and are a widely used cellular model for the human ovary. Typically, GCs are cultured at atmospheric O2 levels (approximately around 20%), yet the O2 conditions in vivo, especially in the preovulatory follicle, are estimated to be much lower. Therefore, we comprehensively evaluated the consequences of atmospheric versus hypoxic (1% O2) conditions for 4 days on human GCs. We found lower cellular RNA and protein levels but unchanged cell numbers at 1% O2, indicating reduced transcriptional and/or translational activity. A proteomic analysis showed that 391 proteins were indeed decreased, yet 133 proteins were increased under hypoxic conditions. According to gene ontology (GO) enrichment analysis, pathways associated with metabolic processes, for example amino acid-catabolic-processes, mitochondrial protein biosynthesis, and steroid biosynthesis, were downregulated. Pathways associated with glycolysis, chemical homeostasis, cellular response to hypoxia, and actin filament bundle assembly were upregulated. In accordance with lower CYP11A1 (a cholesterol side-chain cleavage enzyme) levels, progesterone release was decreased. A proteome profiler, as well as IL-6 and IL-8 ELISA assays, revealed that hypoxia led to increased secretion of pro-inflammatory and angiogenic factors. Immunofluorescence studies showed nuclear localization of hypoxia-inducible factor 1α (HIF1α) in human GCs upon acute (2 h) exposure to 1% O2 but not in cells exposed to 1% O2 for 4 days. Hence, the role of HIF1α may be restricted to initiation of the hypoxic response in human GCs. The results provide a detailed picture of hypoxia-induced phenotypic changes in human GCs and reveal that chronically low O2 conditions inhibit the steroidogenic but promote the inflammatory phenotype of these cells.

Endurance exercise training changes the limitation on muscle in normoxia from the capacity to utilize O2 to the capacity to transport O2.

Maximal oxygen (O2 ) uptake ( ) is an important parameter with utility in health and disease. However, the relative importance of O2 transport and utilization capacities in limiting muscle before and after endurance exercise training is not well understood. Therefore, the present study aimed to identify the mechanisms determining muscle pre- and post-endurance exercise training in initially sedentary participants. In five initially sedentary young males, radial arterial and femoral venous (blood samples), leg blood flow (thermodilution), and myoglobin (Mb) desaturation (1 H nuclear magnetic resonance spectroscopy) were measured during maximal single-leg knee-extensor exercise (KE) breathing either 12%, 21% or 100% O2 both pre and post 8weeks of KE training (1h, 3times per week). Mb desaturation was converted to intracellular using an O2 half-saturation pressure of 3.2mmHg. Pre-training muscle was not significantly different across inspired O2 conditions (12%: 0.47±0.10; 21%: 0.52±0.13; 100%: 0.54±0.01Lmin-1 , all q>0.174), despite significantly greater muscle mean capillary-intracellular gradients in normoxia (34±3mmHg) and hyperoxia (40±7mmHg) than hypoxia (29±5mmHg, both q<0.024). Post-training muscle was significantly different across all inspired O2 conditions (12%: 0.59±0.11; 21%: 0.68±0.11; 100%: 0.76±0.09mmHg, all q<0.035), as were the muscle mean capillary-intracellular gradients (12%: 32±2; 21%: 37±2; 100%: 45±7mmHg, all q<0.029). In these initially sedentary participants, endurance exercise training changed the basis of limitation on muscle in normoxia from the mitochondrial capacity to utilize O2 to the capacity to transport O2 to the mitochondria. KEY POINTS: Maximal O2 uptake is an important parameter with utility in health and disease. The relative importance of O2 transport and utilization capacities in limiting muscle maximal O2 uptake before and after endurance exercise training is not well understood. We combined the direct measurement of active muscle maximal O2 uptake with the measurement of muscle intracellular before and after 8 weeks of endurance exercise training. We show that increasing O2 availability did not increase muscle maximal O2 uptake before training, whereas increasing O2 availability did increase muscle maximal O2 uptake after training. The results suggest that, in these initially sedentary participants, endurance exercise training changed the basis of limitation on muscle maximal O2 uptake in normoxia from the mitochondrial capacity to utilize O2 to the capacity to transport O2 to the mitochondria.

The impact of cycling hypoxia on the phenotype of HPV-positive cervical cancer cells.

Cycling hypoxia (cycH) is a prevalent form of tumor hypoxia that is characterized by exposure of tumor cells to recurrent phases of hypoxia and reoxygenation. CycH has been associated with a particularly aggressive cellular phenotype of tumor cells and increased therapy resistance. By performing comparative analyses under normoxia, physoxia, chronic hypoxia, and cycH, we here uncover distinct effects of cycH on the phenotype of human papillomavirus (HPV)-positive cervical cancer cells. We show that-other than under chronic hypoxia-viral E6/E7 oncogene expression is largely maintained under cycH as is the E6/E7-dependent regulation of p53 and retinoblastoma protein. Further, cycH enables HPV-positive cancer cells to evade prosenescent chemotherapy, similar to chronic hypoxia. Moreover, cells under cycH exhibit a particularly pronounced resistance to the proapoptotic effects of Cisplatin. Quantitative proteome analyses reveal that cycH induces a unique proteomic signature in cervical cancer cells, which includes a significant downregulation of luminal lysosomal proteins. These encompass the potentially proapoptotic cathepsins B and cathepsin L, which, however, appear not to affect the response to Cisplatin under any of the O2 conditions tested. Rather, we show that the proapoptotic Caspase 8/BH3-interacting domain death agonist (BID) cascade plays a pivotal role for the efficiency of Cisplatin-induced apoptosis in HPV-positive cancer cells under all investigated O2 conditions. In addition, we provide evidence that BID activation by Cisplatin is impaired under cycH, which could contribute to the high resistance to the proapoptotic effects of Cisplatin. Collectively, this study provides the first insights into the profound phenotypic alterations induced by cycH in HPV-positive cancer cells, with implications for their therapeutic susceptibility.

Effects of energy-share and ambient oxygen concentration on hydrogen-diesel dual-fuel direct-injection (H2DDI) combustion in compression-ignition conditions

This study investigates the ignition and combustion characteristics of interacting hydrogen (H2) and diesel surrogate jets under simulated compression-ignition engine conditions. The experimental setup includes two converging single-hole injectors in an optically accessible constant-volume combustion chamber (CVCC). The parameters varied in the study are fuel injection durations and ambient O2 concentrations (10 to 21 vol.%). The results show that a longer interaction between the diesel products and the H2 jet is required to achieve ignition of the H2 jet at lower O2 concentrations. Once ignited, the flame stabilises near or at the nozzle, except under the lowest ambient O2 condition of 10 vol.% where a lifted flame is observed. The lift-off response, however, is influenced by the relative injection duration of the fuels, with the interaction between the incoming H2 jet and the diesel combustion recession products possibly playing a role. The interaction between the jets also affects the recorded intensity and the distribution of the diesel fuel jet soot zone.

Hypoxia-inducing cryogels uncover key cancer-immune cell interactions in an oxygen-deficient tumor microenvironment.

Hypoxia is a major factor shaping the immune landscape, and several cancer models have been developed to emulate hypoxic tumors. However, to date, they still have several limitations, such as the lack of reproducibility, inadequate biophysical cues, limited immune cell infiltration, and poor oxygen (O2) control, leading to non-pathophysiological tumor responses. Therefore, it is essential to develop better cancer models that mimic key features of the tumor extracellular matrix and recreate tumor-associated hypoxia while allowing cell infiltration and cancer-immune cell interactions. Herein, hypoxia-inducing cryogels (HICs) have been engineered using hyaluronic acid (HA) to fabricate three-dimensional microtissues and model a hypoxic tumor microenvironment. Specifically, tumor cell-laden HICs have been designed to deplete O2 locally and induce long-standing hypoxia. HICs promoted changes in hypoxia-responsive gene expression and phenotype, a metabolic adaptation to anaerobic glycolysis, and chemotherapy resistance. Additionally, HIC-supported tumor models induced dendritic cell (DC) inhibition, revealing a phenotypic change in the plasmacytoid DC (pDC) subset and an impaired conventional DC (cDC) response in hypoxia. Lastly, our HIC-based melanoma model induced CD8+ T cell inhibition, a condition associated with the downregulation of pro-inflammatory cytokine secretion, increased expression of immunomodulatory factors, and decreased degranulation and cytotoxic capacity of T cells. Overall, these data suggest that HICs can be used as a tool to model solid-like tumor microenvironments and has great potential to deepen our understanding of cancer-immune cell relationship in low O2 conditions and may pave the way for developing more effective therapies.

Biofilm formation and cell plasticity drive diazotrophy in an anoxygenic phototrophic bacterium.

The contribution of non-cyanobacterial diazotrophs (NCDs) to total N2 fixation in the marine water column is unknown, but their importance is likely constrained by the limited availability of dissolved organic matter and low O2 conditions. Light could support N2 fixation and growth by NCDs, yet no examples from bacterioplankton exist. In this study, we show that the phototrophic NCD, Rhodopseudomonas sp. BAL398, which is a member of the diazotrophic community in the surface waters of the Baltic Sea, can utilize light. Our study highlights the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions and the role of cell plasticity in regulating these processes. Our findings have implications for the general understanding of the ecology and importance of NCDs in marine waters.

Reducing energy disorder by stabilizing octahedral lattice with thiocyanate for efficient and stable Sn-Pb mixed perovskite solar cells

The easily generated energy disorder within Sn-Pb perovskite due to the oxidation of Sn2+ into Sn4+ could lead to enhanced Urbach energy (EU) and severe nonradiative energy loss. Here, we reveal the degradation mechanism of Sn-Pb mixed perovskite films under light/O2 and only O2 conditions as well as the relationship between perovskite degradation and energy disorder. Furthermore, we develop an energy disorder regulation strategy of using NH4SCN as an additive for Sn-Pb perovskite films, which exists at grain boundaries to promote the carrier transport effectively and suppress the oxidation of Sn2+. Beneficial from the coordination of SCN– with under-coordinated Sn2+ and Pb2+, the octahedral structure is well stabilized and it largely reduces the Urbach energy and energy disorder in Sn-Pb perovskite. As a result, the 5% NH4SCN treated Sn-Pb mixed perovskite solar cells achieve a power conversion efficiency of 21.48%. The unencapsulated devices retained 87% of their initial PCE in the N2 atmosphere after 200 h of maximum power point tracking.

High-temperature performance of thermal environmental barrier coatings in 90%H2O-10%O2 conditions at 1475 °C

The performance of 50HfO2-50SiO2/YxYb(2−x)Si2O7 thermal environmental barrier coating prepared using atmospheric plasma spraying was investigated in the Al2O3 tube furnace in 90%H2O-10%O2 conditions at 1475 °C. The results showed that YxYb(2−x)Si2O7 layer was contaminated by alumina impurities during the testing process. The thermally grown oxide layer was formed at the bond coat/SiC interface, it grew as the cycles increased. Furthermore, the (Y/Yb)2O3-HfO2 solid solution with a higher coefficient of thermal expansion was formed at YxYb(2−x)Si2O7/50HfO2-50SiO2 interface. The horizontal cracks were the principal factor that caused the failure of 50HfO2-50SiO2/YxYb(2−x)Si2O7. 50HfO2-50SiO2/YxYb(2−x)Si2O7 protected SiC for 25 cycles in steam conditions.

High-performance di-piperidinium-crosslinked poly(p-terphenyl piperidinium) anion exchange membranes

Anion exchange membranes (AEMs) are the core component of anion exchange membrane fuel cells (AEMFCs), among which poly(aryl piperidinium) (PAP) based AEMs have been studied. Herein, we report some scalable di-piperidinium cationic crosslinkers to enhance the mechanical properties, ionic conductivity and alkaline stability of PAP-based AEMs. The results show that the morphology of AEMs can be affected by adjusting the length of crosslinker. PTP-DPC/C6-50% shows a high OH− conductivity (80 °C, 131.2 mS cm−1) due to its microphase separation. It also has excellent elongation at break (20.8%) and tensile strength (36.5 MPa). The peak power density of the PTP-DPC/C6-50% based cell can reach 616.2 mW cm−2 under H2–O2 conditions. The crosslinked network formed by long alkyl spacer chains is helpful to improve the alkaline stability of the AEM. After alkaline stability test, the conductivity of the PTP-DPC/C10-50% membrane maintained at 92.2%.

Abstract B023: Using hypoxia to improve tumor infiltrating lymphocytes therapy in different subtypes of renal cell carcinoma

Abstract BACKGROUND: Improving the long-term efficacy for advanced renal cell carcinoma (RCC) remains challenging after progression on first line therapy. Adoptive cell therapy (ACT) using tumor infiltrating lymphocytes (TIL) is a promising personalized immunotherapeutic approach to treating solid tumors. Previously, TIL therapy for clear cell RCC patients showed moderate success but did not account for the distinct immune microenvironments in different subtypes of RCC such as clear cell (ccRCC), papillary (pRCC) or unclassified (uRCC) known to have different response to immunotherapy. In addition, hypoxia plays a critical role in tumor progression and therapy resistance in RCC. Therefore, the aim of this study was to evaluate TIL expansion from different subtypes of RCC under varying oxygen concentrations. METHODS: Tumor types collected from 48 patients included ccRCC (81.25%), pRCC (16.7%) and uRCC (8.3%). Tumors were minced into fragments and cultured for 4 weeks in media supplemented with high dose IL-2 (6000 IU/mL). At the end of the 4 weeks, TIL were further expanded using a rapid expansion protocol (REP) in either 20% or 5% oxygen. TIL expansion, reactivity to autologous tumor, and phenotype were evaluated in pre-REP and post-REP samples. RESULTS: Among the ccRCC, 91.7% of the samples expanded, while 100% of the pRCC and uRCC expanded. pRCC expanded more TIL than ccRCC (1.05e8 vs 6.7e7 total TIL expanded, respectively) while uRCC expanded less than the other subtypes (2.03e7). Pre-REP reactivity against autologous tumors was high for all the subtypes (88.3%, 75% and 100% for ccRCC, pRCC and uRCC respectively). The T-cell phenotype across subtypes showed a tendency of more CD4+ T-cells and less CD8+ T-cells for pRCC and uRCC, compared to ccRCC. All subtypes that underwent REP were able to expand in both 20% and 5% O2 (hypoxia) conditions. TIL expanded in hypoxia had a significantly higher percentage of tissue resident memory T-cells (CD69+CD103+; 15.1%, p&amp;lt;0.0001) when compared to the pre-REP TIL population (2%) or TIL expanded at 20% O2 (3.1%). CONCLUSION: These results demonstrate the feasibility of expanding tumor-reactive TIL from different subtypes of RCC for the first time, and highlight the advantage of exposing TIL to hypoxic conditions to enhance the differentiation of resident memory T-cells in TIL products. Citation Format: Marine Potez, Mohammed Alkhouli, Johannes Ali, Michael Carter, Matthew Beatty, Shari Pilon-Thomas, Jad Chahoud. Using hypoxia to improve tumor infiltrating lymphocytes therapy in different subtypes of renal cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference: Advances in Kidney Cancer Research; 2023 Jun 24-27; Austin, Texas. Philadelphia (PA): AACR; Cancer Res 2023;83(16 Suppl):Abstract nr B023.

The Role of Concentration, Site, and O Vacancy on Magnetic and Optical Properties of Cu‐Doped Anatase TiO2

Cu‐doped is a dilute magnetic semiconductor with excellent electrical, magnetic, and optical properties. Herein, first‐principles methods are employed to investigate its electronic structure, magnetic properties, and optical behavior. The results demonstrate that Cu‐doped exhibits intrinsic ferromagnetism. The presence of O vacancies facilitates the ferromagnetic exchange between Cu ions by forming bound magnetic polarons (BMPs). This finding validates the BMPs model and explains for the decrease in magnetic properties during annealing under O2 conditions. As the concentration of Cu increases, the system undergoes a transition from a semiconductor to a metal. Cu ions exhibit a preference for a compact configuration and display either paramagnetism or antiferromagnetism. The spin polarization can be effectively controlled from 0% to 100% by adjusting the concentration and site of Cu. Additionally, Cu doping leads to a reduction in the bandgap and an extension of the absorption range into the infrared region. The absorption intensity is positively correlated with the concentration. The presence of a spin‐polarized intermediate band indicates a correlation between the spin of the excited electron and the energy of the absorbed photon. Overall, Cu‐doped shows significant potential for applications in spintronics and spin‐related optics, including photospintronics and spin photocatalysis.

The effect of preconditioning hypoxia in schwann-like-cells-derived adipose mesenchymal stem cells and rat sciatic nerve-derived stem cells: experimental research.

This study aims to explore the response of Schwann-like cells derived from adipose-derived mesenchymal stem cells (SLCs) and Schwann cells rat sciatic nerve-derived stem cells (SCs) with their secretomes under normoxic and hypoxic conditions in vitro. SLCs and SCs were isolated from the adipose tissue and the sciatic nerve of the adult white male rat strain Wistar. Cells were incubated in 21% O2 (normoxic group) and 1%, 3%, and 5% O2 (hypoxic group) conditions. Concentration values of transforming growth factor-β (TGF-β), basic Fibroblast Growth factor (bFGF), brain-derived neurotrophic factor, glial-derived neurotrophic factor, vascular endothelial growth factor, and nerve growth factor were detected and calculated utilizing an enzyme-linked immunosorbent assay, and the growth curve was described. SLCs and SCs indicated positive expression for mesenchymal markers and negative expression for hematopoietic markers. Normoxic conditions SLCs and SCs showed elongated and flattened morphology. Under hypoxic conditions, SLCs and SCs showed a classic fibroblast-like morphology. Hypoxia 1% gave the highest concentration in TGF-β and bFGF from the SLCs group and TGF-β, bFGF, brain-derived neurotrophic factor, and vascular endothelial growth factor from the SCs group. No significant differences in concentration of growth factors between the SLCs group compared to SCs group in all oxygen groups. Preconditioning hypoxia has an effect on the composing of SLCs, SCs, and their secretomes in vitro; no significant differences in concentration of growth factors between the SLCs group compared with the SCs group in all oxygen groups.

Soil pore structure mediates the effects of soil oxygen on the dynamics of greenhouse gases during wetting–drying phases

The timing and magnitude of greenhouse gas (GHG) production depend strongly on soil oxygen (O2) availability, and the soil pore geometry characteristics largely regulate O2 and moisture conditions relating to GHG biochemical processes. However, the interactions between O2 dynamics and the concentration and flux of GHGs during the soil moisture transitions under various soil pore conditions have not yet been clarified. In this study, a soil-column experiment was conducted under wetting–drying phases using three pore-structure treatments, FINE, MEDIUM, and COARSE, with 0 %, 30 %, and 50 % coarse quartz sand applied to soil, respectively. The concentrations of soil gases (O2, nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4)) were monitored at a depth of 15 cm hourly, and their surface fluxes were measured daily. Soil porosity, pore size distribution, and pore connectivity were quantified using X-ray computed microtomography. The soil O2 concentrations were found to decline sharply as soil moisture increased to the water holding capacities of 0.46, 0.41, and 0.32 cm cm−3 in the FINE, MEDIUM, and COARSE, respectively. The dynamic patterns of the O2 concentrations varied across the soil pore structures, decreasing to anaerobic in FINE (<0.01 %) and MEDIUM (0.02 %), and to hypoxic (4.42 %) in COARSE. Correspondingly, the soil N2O concentration was the highest in FINE (101 μL L−1) and the lowest in COARSE (10 μL L−1), whereas the highest surface N2O flux was observed in MEDIUM (131 μg N m−2 h−1). As soil CO2 concentrations declined, CO2 fluxes increased from FINE to MEDIUM to COARSE. Most pores of FINE, MEDIUM, and COARSE were 15–80 μm, 85–100 μm, and 105–125 μm, respectively, in terms of diameter. The X-ray CT visible (>15 μm) porosity in FINE, MEDIUM and COARSE were 0.09, 0.17, and 0.28 mm3 mm−3, respectively. The corresponding Euler-Poincaré numbers were 180,280, 76,705, and −10,604, respectively, indicating higher connectivity in COARSE than in MEDIUM or FINE. In soil dominated by small air-filled porosity which limits gas diffusion and result in low soil O2 concentration, N2O concentration was increased and CO2 flux was inhibited as the moisture content increased. The turning point in the sharp decrease in O2 concentration was found to correspond with a moisture content, and a pore diameter of 95–110 μm was associated with the critical turning point between holding water and O2 depletion in soil. These findings suggest that O2-regulated biochemical processes are key to the production and flux of GHGs, which in turn are dependent on the soil pore structure and a coupling relationship between N2O and CO2. Improved understanding of the intense effect of soil physical properties provided an empirical foundation for the future development of mechanistic prediction models for how pore-space scale processes with high temporal (hourly) resolution up to GHGs fluxes at larger spatial and temporal scales.

P-227 ICSI outcomes after using in-situ microfluidics of fluidic walls versus DGC: a prospective non-inferiority comparative pilot study in sibling oocytes

Abstract Study question Does the novel strategy in-situ microfluidics (isM) yield comparable ICSI outcomes to the control sperm selection methodology density gradient centrifugation (DGC)? Summary answer ICSI outcomes show that handmade in-situ microfluidics of fluidic walls are as effective as DGC to achieve fertilization and usable day 5 blastocyst formation rate. What is known already Microfluidics technologies are proving their capability to select suitable sperm for ICSI. Increasingly, publications show novel and ingenious microfluidics strategies aimed to integrate sperm biomimicry during in vitro sperm selection while simplifying the IVF-workflow. We recently designed a microfluidics system which allows selecting sperm for ICSI in the same ICSI-dish, only using microfluidics and disregarding centrifugation, washing and plasticware. A previous proof-of-concept study showed that this methodology was efficient to select suitable sperm for ICSI as it could separate at least 20 progressive spermatozoa in less than 15 minutes in a clean microdroplet free of any remaining seminal plasma. Study design, size, duration The present pilot study included a total of 280 fresh MII-oocytes allocated in a 1:1 ratio to the study (isM-ICSI) and control (DGC-ICSI) groups. The statistical power was established at 80% at a CI 95%. For comparison we relied in the KPIs: ICSI normal fertilization rate (INFR) and Day 5 usable blastocyst rate (D5UBR). The non-inferiority margin (Δ) was established using 2-sigma warning limit and our historical control mean values (ΔINFR = 7% and ΔD5UBR = 10%). Participants/materials, setting, methods An informed consent was signed by all participants. The comparative study included 29 consecutive ICSI cases performed in fresh oocytes from women under 40 years old and with an oocyte yield ≥6 MII. All semen samples had ≥1 × 106/ml progressive spermatozoa and were split into three aliquots: 1-seminogram (100 µl), 2-isM (10 µl), 3-DGC (surplus). Embryos were cultured in bench-top Time-lapse incubators, using GTL-media under 6,4% CO2 and 5% O2 conditions up to blastocyst stage. Main results and the role of chance Sperm characteristics showed the following total mean values for total concentration (42,83 ± 31,1 × 106/ml), total motility (51,28 ± 14,16 %) and progressive sperm concentration (17 ± 12 × 106/ml). The mean number of MII per patient was 9,66. From the total number of oocytes (n = 280), 139 were allocated to isM (study group) and 141 to DGC (control group) groups. INFR was 72,0 % vs 76,6 %, respectively. Non-significant differences were observed (p = 0,54). We observed that the mean total number of usable blastocysts (day 5/6) per patient was 1,83 (53/29) in isM vs 1,66 (48/29) in DGC. Moreover, D5UBR was 53,0% vs 44,4 % (p = 0,26) with a difference between the study and the control of within the non-inferiority margin. We observed a lower rate of arrested embryos (up to day 6) in the study group (19,0% vs 30,0%), although results were not statistically significant (p = 0,08). Limitations, reasons for caution This pilot study includes a limited number of oocytes. The present isM protocol depends on a free-hand preparation. Although the use of templates and the training reduces inter and intra-operator variability, a ready-to-use surface would benefit the operability. Further investigation is required to evaluate clinical pregnancy and live birth outcomes. Wider implications of the findings Sperm DNA fragmentation is cited among the causes of embryo arrest. As the use of isM resulted in a lower proportion of arrested embryos, exploring its capacity to select non-fragmented sperm warrants further interest. The isM protocol streamlines sperm selection for ICSI, reduces costs and risks along the procedure. Trial registration number na

Combined effects of ocean deoxygenation, acidification, and phosphorus limitation on green tide macroalga, Ulva prolifera

Ocean deoxygenation, acidification, and decreased phosphorus availability are predicted to increase in coastal ecosystems under future climate change. However, little is known regarding the combined effects of such environmental variables on the green tide macroalga Ulva prolifera. Here, we provide quantitative and mechanistic understanding of the acclimation mechanisms of U. prolifera to ocean deoxygenation, acidification, and phosphorus limitation under both laboratory and semi-natural (mesocosms) conditions. We found that there were significant interactions between these global environmental conditions on algal physiological performance. Although algal growth rate and photosynthesis reduced when the nitrogen-to‑phosphorus (N/P) ratio increased from 16:1 to 35:1 under ambient CO2 and O2 condition, they remained constant with further increasing N/P ratios of 105:1, 350:1, and 1050:1. However, the increasing alkaline phosphatase activities at high N/P ratios suggests that U. prolifera could use organic P to support its growth under phosphorus limitation. Deoxygenation had no effect on specific growth rate (SGR) but decreased photosynthesis under low N/P ratios of 16:1, 35:1, and 105:1, with reduced activities of several enzymes involved in N assimilation pathway being observed. Elevated CO2 promoted algal growth and alleviated the negative effect of deoxygenation on algal photosynthesis. The patterns of responses to high CO2 and low O2 treatments in in situ experiments were generally consistent with those observed in laboratory experiments. Our results generally found that the strong physiological acclimation capacity to elevated CO2, low O2, and high N/P could contribute to its large-scale blooming in coastal ecosystem.