Oxygen Tension Research Articles

Exploring the Changes in IL-6 and Related Cytokines in Angiogenesis after Tibial Transverse Transplantation in Diabetic Foot Ulcers.

The transverse tibial transfer technique is employed primarily to treat diabetic foot ulcers (DFUs), aiming to enhance leg circulation and promote new blood vessel growth. This technique is also beneficial for various conditions associated with poor blood flow in the lower extremities. However, there is no clear molecular mechanism to explain the relationship between the transverse tibial transfer technique and angiogenesis in patients with diabetic foot. This study aims to preliminarily explore the change of IL-6 and related cytokines in promoting angiogenesis during transverse tibial transplantation, providing a direction for future research. We retrospectively assessed a study from April 2022 to November 2023 on 76 patients with severe DFUs at Wagner stages 3-4. Flow cytometry was used to detect the levels of 12 cytokines in serum before the operation and 3, 7, 14, 21, and 35 days after the operation. Ankle-brachial index (ABI), transcutaneous oxygen tension (TcPO2), and glycosylated hemoglobin (Hba1c) were recorded at admission and discharge. We examined the variations in cytokine levels, wound healing duration, amputation rates, infection incidence, and other key outcomes. In our investigation, a total of 76 individuals participated, comprising 49 males and 27 females. These subjects had an average age of 64.7 years, with a standard deviation of 13 years. The mean ulcer healing time was 74 ± 31 days, amputation occurred in 3 patients, pin tract infection occurred in one patient (1.3%), and incision infection occurred in one patient (1.3%). By day 35 following the surgery, both the ABI and TcPO2 values showed a significant increase from their preoperative levels. HbA1c significantly improved compared with presurgery (p < 0.001), IL-6 levels were significantly increased compared with presurgery (p < 0.05), and then decreased. The transverse tibial transfer (TTT) technique is safe and efficient for managing DFUs. The wound healing time in patients who smoke or consume alcohol is statistically significant compared with that of nonsmoking and nondrinking patients. IL-6 exhibited substantial changes at various postoperative time points. Future research could investigate the role of IL-6 in tibial transverse translation.

Design and conductivity optimization of La0.3Sr0.7TiO3/La0.8Sr0.2MnO3 bi-layer structures as tubular segmented-in-series solid oxide fuel cell interconnect☆

This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells (SOFCs) in reducing and oxidizing atmospheres. To address this challenge, a bi-layer perovskite ceramic interconnect was designed by controlling the oxygen partial pressure, because of the strong correlation between the conductivity of strontium-doped lanthanum titanate (LST) and the oxygen partial pressure. The LST powder was prepared using solid-phase and sol-gel methods, and their influence on particle size and sintering behavior was compared. LST/lanthanum strontium manganite (LSM) bi-layer ceramic interconnects with varying thicknesses were fabricated through screen printing and co-sintering. The results demonstrate favorable interfacial bonding and excellent chemical compatibility between the ceramic layers. The conductivity of the bi-layer interconnect exhibits a temperature-dependent behavior, peaking at 550 °C. Simulation calculations and research findings validate that the conductivity of the bi-layer interconnect is determined by the thickness of the LSM layer and the oxygen partial pressure at the interconnect interface. Optimal conductivity is achieved with a bi-layer interconnect consisting of approximately 15 μm of LST and 4 μm of LSM. This can be attributed to the efficient regulation of oxygen partial pressure at the interface, effectively mitigating LSM decomposition caused by low oxygen partial pressure and the subsequent reduction in conductivity. These results provide valuable fundamental data and methodology for the development of high-performance interconnects for tubular segmented-in-series SOFCs.

Lower or Higher Oxygenation Targets in ICU patients with COVID-19 – A secondary Bayesian analysis of the HOT-COVID trial

BackgroundIn the Handling Oxygenation Targets in COVID-19 (HOT-COVID) trial, a partial pressure of arterial oxygen (PaO2) target of 60 mmHg compared to 90 mmHg resulted in more days alive without life support at 90 days in adult ICU patients with coronavirus disease 2019 (COVID-19) and hypoxemia. The trial was stopped after enrolling 726 of 780 planned patients due to slow recruitment. Here, we present the preplanned Bayesian analysis of the HOT-COVID trial. Research QuestionWhat are the probabilities of any and of clinically relevant benefits from a PaO2 target of 60 mmHg versus 90 mmHg in adult ICU patients with COVID-19 and hypoxemia, and is there heterogeneity of treatment effects (HTE) according to selected baseline characteristics? Study Designand Methods We analyzed days alive without life support and 90-day mortality in the HOT-COVID intention-to-treat population (n=697) using Bayesian general linear models to assess probabilities for benefit or harm, including clinically relevant benefits defined as >1 day alive without life support and >2 percentage points lower 90-day mortality. HTE was evaluated based on baseline SOFA scores, PaO2:FiO2, norepinephrine doses, and lactate concentrations. ResultsThe mean difference in days alive without life support was 5.7 days (95% credible interval (CrI): 0.2 to 11.2), with a 95.2% probability of clinically relevant benefit and a 98.0% probability of any benefit from the lower PaO2 target. The risk difference in 90-day mortality was -4.6 percentage points (95% CrI: -11.8 to 2.6), with a 76.5% probability of a clinically relevant benefit from the lower target. HTE analyses revealed potential interaction with baseline norepinephrine dose and lactate concentrations for both outcomes. InterpretationIn ICU patients with COVID-19 and hypoxemia, we found high probability for a clinically relevant benefit of targeting a PaO2 of 60 mmHg vs. 90 mmHg on number of days alive without life support.

A tailored machine learning approach for mortality prediction in severe COVID-19 treated with glucocorticoids.

<sec><title>BACKGROUND</title>The impact of severe COVID-19 pneumonia on healthcare systems highlighted the need for accurate predictions to improve patient outcomes. Despite the established efficacy of glucocorticoids (GCs), variable patient responses are observed, and the existing clinical scores are limited in predicting non-responders. We propose a machine learning (ML) based approach to predict mortality in COVID-19 pneumonia treated with GCs.</sec><sec><title>METHODS</title>This is an ML-driven retrospective analysis involving 825 patients. We leveraged XGBoost to select the most appropriate features from the initial 52, including clinical and laboratory data. Six different ML techniques were compared. Shapley additive explanation (SHAP) values were used to describe the influence of each feature on classification. Internal validation was performed.</sec><sec><title>RESULTS</title>Nine key predictors of death were identified: increasing C-reactive protein (CRP), decreasing arterial partial pressure of oxygen to fraction of inspired oxygen ratio (PaO₂/FiO₂), age, coronary artery disease, invasive mechanical ventilation, acute renal failure, chronic heart failure, PaO₂/FiO₂ earliest value, and body mass index. Random forest achieved the highest test area under the receiver operating characteristic curve at 0.938 (95% CI 0.903-0.969). SHAP values highlighted age and PaO₂/FiO₂ improvement as the most influential features; the latter showed a higher impact than CRP reduction over time.</sec><sec><title>CONCLUSION</title>The proposed ML algorithm effectively predicts the risk of hospital death in COVID-19 pneumonia patients undergoing GCs. This approach can be adapted to datasets measuring similar clinical variables.</sec>.

Degradation behavior of yttria-stabilized zirconia in thermal barrier coatings under reducing environments after short-term heat treatment

The gradual transition of hydrogen as a fuel for land-based gas turbines has resulted in direct changes to the combustion environment. The inadequate combustion of hydrogen fuel can lead to a transition from an oxidizing environment to a partially reducing environment, and further introduces a new potential failure mode for existing thermal barrier coating materials. In this study, tests were conducted on thermal barrier coating samples at 1000 °C in Ar + 5 % O2 and Ar + 5 % H2 environments, in addition to samples subjected to heat-treatment in pure argon and air environments to provide a comparison against low oxygen partial pressure and conventional failure modes. The results demonstrated that the degree of sintering of the top coat decreased gradually with a decreasing oxygen partial pressure, and was significantly inhibited in a reducing environment. Faster cooling rates led to the expansion of vertical cracks in the top coat toward the interface, which was accompanied by the generation of numerous transverse cracks in the reducing environment. In contrast, the structure of the top coat remained intact in the other three environments. Furthermore, effective methods for improving the coating durability in reducing environments are discussed. This study therefore contributes to a comprehensive understanding of the failure behavior of thermal barrier coatings in reducing environments, providing new insights into enhancing the stability under such conditions.

Li3V2(PO4)3 sintering atmosphere optimisation for its integration in All-Solid-State Batteries

Integration of active materials into the architecture of all-solid-state batteries represents a significant scientific inquiry. Li3V2(PO4)3 (LVP), a positive and negative electrode active material for Li-ion batteries, has been subject to extensive research to elucidate its electrochemical behaviour during cycling processes. However, the comprehensive analysis of its thermal behaviour under different sintering atmosphere conditions has remained underexplored, particularly in the context of its compatibility with solid electrolytes. This study presents a meticulous study of sintering process under different atmospheres with precise control over oxygen partial pressure.Interestingly, we were able to sinter LVP and obtain dense, pure ceramic phase under slightly oxidising atmosphere, characterized by conductivity properties analogous to those observed in samples sintered under Ar/H2 conditions. The findings of this investigation contribute to the understanding of the optimal conditions required for the sintering of LVP, paving the way for the co-sintering of this material with inorganic solid electrolyte unstable under reducing atmosphere, such as LATP.

Comparison of Metabolic, Ionic, and Electrolyte Responses to Exhaustive Low-Load Strength Training With and Without Blood Flow Restriction and High-Load Resistance Training.

Low-load blood-flow-restriction resistance training (LL-BFR-RT) is gaining popularity, but its physiological effects remain unclear. This study aimed to compare LL-BFR-RT with low-load resistance exercise (LL-RT) and high-load resistance exercise (HL-RT) on metabolism, electrolytes, and ions in the lower extremities by invasive catheter measurements, which are crucial for risk assessment. Ten healthy men (27.6 ± 6.4 years) completed three trials of knee-extensor exercises with LL-RT (30% 1RM), LL-BFR-RT (30% 1RM, 50% limb occlusion pressure), and HL-RT (75% 1RM). The exercise protocol consisted of four sets to voluntary muscle failure with 1 min of rest between sets. Blood gas analysis was collected before, during, and after each trial through intravenous catheters at the exercising leg. LL-BFR-RT had lower total workload (1274 ± 237 kg, mean ± SD) compared to LL-RT (1745 ± 604 kg), and HL-RT (1847 ± 367 kg, p < 0.01), with no difference between LL-RT and HL-RT. Pain perception did not differ significantly. Exercise-induced drop in oxygen partial pressure, lactate accumulation and electrolyte shifts (with increased [K+]) occurred during under all conditions (p < 0.001). Creatine kinase and lactate dehydrogenase increased significantly 24- and 48-h postexercise under all three conditions (p < 0.001). This study, using invasive catheter measurements, found no significant differences in metabolic, ionic, and electrolyte responses among LL-BFR-RT, LL-RT, and HL-RT when exercised to voluntary muscular failure. LL-BFR-RT reduced time to failure without specific physiological responses.

Phase selectivity upon flash-lamp annealing of sputter deposited amorphous titanium oxide films

We report the impact of flash-lamp-annealing (FLA) on the structural evolution of amorphous titania (TiO2) films produced by DC reactive magnetron sputtering. TiO2 films were grown at room-temperature at different oxygen partial pressure (PO2) and subsequently annealed as a function of the FLA energy density. X-ray diffraction confirms that FLA induces phase formation from the initial amorphous state with a general transition from anatase to rutile by increasing the FLA energy density (temperature). Interestingly, the transformation onset of anatase to rutile is achieved at lower energy densities for higher PO2. On the contrary, films with a highly resilient anatase phase can be produced at relatively low PO2. A detailed analysis of the pristine amorphous structure carried out by X-ray absorption near-edge structure indicates the role of oxygen sites in the observed phase transformation. In particular, oxygen vacancies seem to stabilize the anatase phase at high temperatures. The results show the relevance of subtle changes in the initial amorphous structure for phase selectivity in TiO2 films upon FLA.

The effect of in-bed cycling combined with high flow nasal cannula treatment on arterial oxygen and respiratory dynamics in patients with severe respiratory failure: A retrospective study.

To assess the effects of in-bed cycling (IBC) combined with high flow nasal cannula (HFNC) on arterial oxygen and respiratory dynamics in patients with severe respiratory failure (RF). We retrospectively collected clinical data of 103 patients with severe RF, admitted to the intensive care unit (ICU) of The Second Affiliated Hospital of Harbin Medical University from March 2021 to March 2023. Among them, 50 patients had HFNC alone (control group), and 53 patients did IBC in addition to HFNC (observation group). We compared arterial oxygen index, lung function, respiratory dynamics, and clinical efficacy between the two groups. There was no significant difference in the basic data between the two groups (P>0.05). After the treatment, the improvement of the partial pressure of oxygen (PaO2), PaO2/fraction of inspired oxygen (FiO2), arterial oxygen saturation (SaO2), and oxygen delivery (DO2) in the observation group was significantly better than that in the control group (P<0.05). After the treatment, the improvement of lung function in the observation group was better than that in the control group (P<0.05). After the treatment, the end expiratory pulmonary pressure (Ptp-ee) and driving pressure (△Ptp) levels in the observation group were significantly higher, and the duration of ICU hospitalization and the incidence of ICU-acquired weakness(ICU-AW) were significantly lower than those in the control group (P<0.05). IBC combined with HFNC can significantly improve arterial oxygen levels, lung function, and respiratory dynamics in patients with severe RF. IBC in combination with HFNC is associated with shorter stay time in the ICU, reduced of ICU-acquired weakness, and better physical recovery of patients.

Clinicians’ attitudes towards supplemental oxygen for trauma patients – A survey

IntroductionThe Advanced Trauma Life Support guidelines (ATLS; 2018, 10th ed.) recommend an early and liberal supplemental oxygen for all severely injured trauma patients to prevent hypoxaemia. As of 2024, these guidelines remain the most current. This may lead to hyperoxaemia, which has been associated with increased mortality and respiratory complications. We aimed to investigate the attitudes among clinicians, defined as physicians and prehospital personnel, towards the use of supplemental oxygen in trauma cases. Materials and MethodsA European, web-based, cross-sectional survey was conducted consisting of 23 questions. The primary outcome was the question: “In your opinion, should all severely injured trauma patients always be given supplemental oxygen, regardless of arterial oxygen saturation measured by pulse oximetry?”. ResultsThe survey was answered by 707 respondents, which corresponded to a response rate of 52%. The respondents were predominantly male (76%), with the largest representation from Denmark (82%), and primarily educated as physicians (62%). A majority of respondents (73% [95% CI: 70 to 76%]) did not support that supplemental oxygen should always be provided to all severely injured trauma patients without consideration of their arterial oxygen saturation as measured by pulse oximetry (SpO2), with no significant difference between physicians and non-physicians (p = 0.08). Based on the respondents’ preferred dosages, the median initial administered dosage of supplemental oxygen for spontaneously breathing trauma patients with a normal SpO2 in the first few hours after trauma was 0 (interquartile range [IQR] 0-3) litres per minute, with 58% of respondents opting not to provide any supplemental oxygen. The lowest acceptable SpO2 goal in the first few hours after trauma was 94% (IQR 92-95). In clinical scenarios with TBI, higher dosage of supplemental oxygen and fraction of inspired oxygen (FiO2) were preferred, as well as targeting partial pressure of oxygen in arterial blood as opposed to adjusting the FiO2 directly, compared to no TBI. ConclusionAlmost three out of four clinicians did not support the administration of supplemental oxygen to all severely injured trauma patients, regardless of SpO2. This corresponds to a more restrictive approach than recommended in the current ATLS (2018, 10th ed.) guidelines.

Evaluation of maternal bromoform supplementation in late gestation on blood parameters of cows and their progeny

Bromoform supplementation has been successful in reducing enteric methanogenesis in ruminants; however, the impacts on the health of these animals are still limited. The current study evaluates the impact of maternal bromoform supplementation on the health of late-gestation cows and their progeny. Pregnant Angus cows (n = 42) were allocated into a control or bromoform group (n = 21 cows per treatment). Bromoform extracted from Asparagopsis armata (7,372 mg/kg) was supplemented once daily. Blood samples were collected from cows before supplementation (baseline). Within 24 h of parturition, blood and colostrum samples were collected from each cow and blood from neonates. Colostrum brix was measured to indicate immunoglobulin content. All data was analysed using the MIXED procedure in SAS.Supplementation of cows with bromoform resulted in increased blood urea to creatinine ratio (P = 0.048), base excess (P = 0.049), total carbon dioxide (TCO2; P = 0.048) and a decrease in blood glutamate dehydrogenase (GLDH; P = 0.031) compared to the control group. For cows in the bromoform group, a trend was observed for higher levels of partial pressure of carbon dioxide (pCO2; P = 0.070) and bicarbonate (HCO3-; P = 0.052), and lower levels of partial pressure of oxygen (pO2; P = 0.058) compared to the control group. Blood gamma-glutamyl transferase (GGT) was elevated in offspring of cows fed bromoform (P = 0.050). The lower blood pO2 of pregnant cows fed bromoform and elevated blood GGT levels in offspring are not well understood and highlight the need for further investigation. Additionally, the low-dose bromoform supplementation affected various blood gas parameters of cows and calves, demonstrating the importance of monitoring these parameters when using different doses of halogenated compounds in livestock.

Oxidation kinetics of Ti6Al4V alloy deposited by wire arc additive manufacturing using argon gas as processing atmosphere

Ti6Al4V alloy is currently the most common metal alloy of the α+β phase type, its application is increasing as it has excellent properties at elevated temperatures. The main users of Ti6Al4V alloy are industries like of aerospace, naval, and biomedical; therefore, Ti6Al4V alloys one of the most studied material worldwide. One of the great advantages that Ti6Al4V alloy offers is the possibility of manufacturing components in situ by means of additive technologies.. Similar studies, in additive manufacturing, have reported the formation of titanium oxide on the surface of the material, followed by an oxygen-enriched region called "α-case". By means of thermogravimetric analysis, the oxidation effect on the surface of Ti6Al4V samples, obtained by wire arc additive manufacturing as well as samples from conventional manufacture, were studied. Argon gas, with an oxygen partial pressure of 1x10-5 atm, was used as the oxidation atmosphere within a range of 550°C to 950°C and oxidatión times of 60 min and 180 min. For the oxidation reaction, the kinetic analyses led to calculate the activation energy as 250 kJ/mol and 166 kJ/mol for the Ti6Al4V alloy processed by conventinal and additive manufacturing, respectively. The results of the of thermogravimetric analysis were fitted to a parabolic-type kinetic model. Furthemore, a mathematical model was proposed to predict the oxidation kinetics. The experimental data were fitted to the mathematical model in the range of 750 - 950°C for Ti6Al4V alloy by wire arc additive manufacturing. The oxidized microstructures were analized by optical and electronic microscopy finding α-case on the surface of the samples.

Parameter quantification for oxygen transport in the human brain

Background and objective:Oxygen is carried to the brain by blood flow through generations of vessels across a wide range of length scales. This multi-scale nature of blood flow and oxygen transport poses challenges on investigating the mechanisms underlying both healthy and pathological states through imaging techniques alone. Recently, multi-scale models describing whole brain perfusion and oxygen transport have been developed. Such models rely on effective parameters that represent the microscopic properties. While parameters of the perfusion models have been characterised, those for oxygen transport are still lacking. In this study, we set to quantify the parameters associated with oxygen transport and their uncertainties. Methods:Effective parameter values of a continuum-based porous multi-scale, multi-compartment oxygen transport model are systematically estimated. In particular, geometric parameters that capture the microvascular topologies are obtained through statistically accurate capillary networks. Maximum consumption rates of oxygen are optimised to uniquely define the oxygen distribution over depth. Simulations are then carried out within a one-dimensional tissue column and a three-dimensional patient-specific brain mesh using the finite element method. Results:Effective values of the geometric parameters, vessel volume fraction and surface area to volume ratio, are found to be 1.42% and 627 [mm2/mm3], respectively. These values compare well with those acquired from human and monkey vascular samples. Simulation results of the one-dimensional tissue column show qualitative agreement with experimental measurements of tissue oxygen partial pressure in rats. Differences between the oxygenation level in the tissue column and the brain mesh are observed, which highlights the importance of anatomical accuracy. Finally, one-at-a-time sensitivity analysis reveals that the oxygen model is not sensitive to most of its parameters; however, perturbations in oxygen solubilities and plasma to whole blood oxygen concentration ratio have a considerable impact on the tissue oxygenation. Conclusions:The findings of this study demonstrate the validity of using a porous continuum approach to model organ-scale oxygen transport and draw attention to the significance of anatomy and parameters associated with inter-compartment diffusion.

Obesity Hypoventilation (Pickwickian) Syndrome – ”The Tip of an Iceberg” in Morbidly Obese Patients

ABSTRACT Obesity hypoventilation syndrome (OHS), also known as Pickwickian syndrome, is a combination of obesity (body mass index (BMI) &gt;30 kg/m2), daytime hypercapnia (arterial carbon dioxide tension &gt;45 mm Hg) and sleep-disordered breathing, after exclusion of other disorders that may cause alveolar hypoventilation. Management of OHS requires a multifaceted approach in the form of weight loss, treatment of existing co-illnesses, pulmonary rehabilitation, and Bi-level positive airway pressure (Bi-PAP) therapy. A 58-year-old lady with a BMI of 50 kg/m2 with symptoms of obstructive sleep apnea (OSA) and OHS presented to the hospital with respiratory distress. She gave a history of breathlessness, snoring, and sleep disturbances for the last 7 years. She was managed by a physician with a diagnosis of obstructive airway disease without further evaluation of sleep disturbance. On admission, she was started on non-invasive ventilation during her initial management. After 72 hours of admission, the patient became stable, and overnight polysomnography was performed to confirm the diagnosis of OHS. After confirmation of the diagnosis, she was started on Bi-PAP therapy along with other supportive therapy for 7 days. She was discharged after 10 days of admission with nocturnal Bi-PAP therapy at home and was enrolled in a comprehensive pulmonary rehabilitation program. Patient is on regular follow-up and has been doing well since then.

Lupus Nephritis: Immune Cells and the Kidney Microenvironment.

Lupus nephritis (LN) is the most common major organ manifestation of the autoimmune disease SLE (lupus), with 10% of those afflicted progressing to ESKD. The kidney in LN is characterized by a significant immune infiltrate and proinflammatory cytokine milieu that affects intrinsic renal cells and is, in part, responsible for the tissue damage observed in LN. It is now increasingly appreciated that LN is not due to unidirectional immune cell activation with subsequent kidney damage. Rather, the kidney microenvironment influences the recruitment, survival, differentiation, and activation of immune cells, which, in turn, modify kidney cell function. This review covers how the biochemical environment of the kidney ( i.e ., low oxygen tension and hypertonicity) and unique kidney cell types affect the intrarenal immune cells in LN. The pathways used by intrinsic renal cells to interact with immune cells, such as antigen presentation and cytokine production, are discussed in detail. An understanding of these mechanisms can lead to the design of more kidney-targeted treatments and the avoidance of systemic immunosuppressive effects and may represent the next frontier of LN therapies.

P02-39 Doxorubicin induced change in filtration permeability in podocytes and glomerular microvascular endothelial cells in co-culture at physiological oxygen tensions

P02-39 Doxorubicin induced change in filtration permeability in podocytes and glomerular microvascular endothelial cells in co-culture at physiological oxygen tensions

Hypercapnia during transcatheter aortic valve replacement under monitored anaesthesia care: a retrospective cohort study

BackgroundAcute intraoperative hypercapnia and respiratory acidosis, which can occur during monitored anaesthesia care (MAC), pose significant cardiopulmonary risks for patients with aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). The...

Degradation behavior of galvanostatic and galvanodynamic cells for hydrogen production from high temperature electrolysis of water

High temperature electrolysis of water using solid oxide electrochemical cells (SOEC) is a promising technology for hydrogen production with high energy efficiency and may promote decarbonization when coupled with renewable energy sources and excess heat from nuclear reactors. Apart from the technoeconomic considerations, commercial deployment of this technology critically depends on the long-term performance and durability of SOEC cells/stacks, especially under dynamic operations to withstand the intermittency of renewable energy. Herein, SOEC operation was conducted under galvanodynamic conditions and compared with galvanostatic cells to examine the effect on degradation behavior at an average current density of −0.75 A cm−2 at 750 °C. While dynamic operation shows no significant impact on the overall degradation rates compared to constant current operation, minor performance improvement was observed at potentials above 1.5 V when switched to galvanodynamic mode. The relatively lower overpotential during dynamic operation could not be explained by the negligible changes in the electrochemical impedance or cell temperature. Multiphysics modeling reveals that the oxygen partial pressure (PO2) in the electrolyte oscillates with the alternating current density under dynamic operations. The minor improvement in cell performance under dynamic mode might be associated with the relatively lower PO2 buildup as compared with that under galvanostatic operation. In addition, dynamic operation at high frequencies could effectively lower the extreme PO2 in the electrolyte, thus relieving stresses in the cells and alleviating cell degradation.

Selective extraction of chromium from chromium-bearing electroplating sludge by pressure oxidation alkaline leaching

The selective extraction of chromium (Cr) from Chromium-bearing electroplating sludge (CES) has positive significance for harmless disposal and reducing dependence on native resources. Herein, the process of pressure oxidation alkaline leaching of CES is reported. The leaching ratio of Cr was reached 89.9 % under the optimal conditions, i.e., temperature of 125℃, NaOH concentration of 1.5 mol/L, liquid-solid ratio of 10, oxygen partial pressure of 2Mpa and reaction time of 2 h, while other elements such as Cu, Ni, Fe and Zn were virtually not leached out. In addition, the concentration of NaOH required for the maximum of the leaching ratio of Cr decreased with the increase of temperature, which attributed to the synergistic effect of temperature and NaOH concentration on the solubility and diffusion coefficient of the oxidant. As the oxygen partial pressure was increased to 2 MPa, the liquid-solid ratio was raised to 10, and the reaction time was extended to 2 h, respectively, the leaching ratio of Cr reached maximum and then remained as a constant. Kinetic studies showed the leaching process of chromium was controlled by chemical reaction, and the apparent activation energy was 112.1 kJ/mol. The efficient selective recovery of Cr is of great significance to reduce the difficulty of comprehensive recovery of valuable metal elements in the CES.

Hypoxia Abrogates Tumor-Suppressive Activities of C/EBPδ in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a dismal disease with a low 5-year survival rate of only 13%. Despite intense research efforts, PDAC remains insufficiently understood. In part, this is attributed to opposing effects of key players being unraveled, including the stroma but also molecules that act in a context-dependent manner. One such molecule is the transcription factor C/EBPδ, where we recently showed that C/EBPδ exerts tumor-suppressive effects in PDAC cells in vitro. To better understand the role of C/EBPδ in different contexts and the development of PDAC, we here build on these findings and assess the effect of C/EBPδ in a PDAC model in mice. We establish that the lack of oxygen in vivo-hypoxia-counteracts the tumor-suppressive effects of C/EBPδ, and identify a reciprocal feedback loop between C/EBPδ and HIF-1α. RNA sequencing of C/EBPδ-induced cells under hypoxia also suggests that the growth-limiting effects of C/EBPδ decrease with oxygen tension. Consequently, in vitro proliferation assays reveal that the tumor-suppressive activities of C/EBPδ are abrogated due to hypoxia. This study demonstrates the importance of considering major physiological parameters in preclinical approaches.