We have developed a reactive oxygen species (ROS) sensor based on nanopores modified with GGGCEG(GPGGA)
CEG. The formation of an intramolecular disulfide bond oxidized by ROS leads to conformation ...changes in GGGCEG(GPGGA)
CEG, which then induces an obvious change in the size of the nanopores and a corresponding ionic current change. This work allows the accurate and dynamic monitoring of ROS through the combination of (GPGGA)
and nanopores.
Supplemental oxygen is often administered liberally to acutely ill adults, but the credibility of the evidence for this practice is unclear. We systematically reviewed the efficacy and safety of ...liberal versus conservative oxygen therapy in acutely ill adults.
In the Improving Oxygen Therapy in Acute-illness (IOTA) systematic review and meta-analysis, we searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, HealthSTAR, LILACS, PapersFirst, and the WHO International Clinical Trials Registry from inception to Oct 25, 2017, for randomised controlled trials comparing liberal and conservative oxygen therapy in acutely ill adults (aged ≥18 years). Studies limited to patients with chronic respiratory diseases or psychiatric disease, patients on extracorporeal life support, or patients treated with hyperbaric oxygen therapy or elective surgery were excluded. We screened studies and extracted summary estimates independently and in duplicate. We also extracted individual patient-level data from survival curves. The main outcomes were mortality (in-hospital, at 30 days, and at longest follow-up) and morbidity (disability at longest follow-up, risk of hospital-acquired pneumonia, any hospital-acquired infection, and length of hospital stay) assessed by random-effects meta-analyses. We assessed quality of evidence using the grading of recommendations assessment, development, and evaluation approach. This study is registered with PROSPERO, number CRD42017065697.
25 randomised controlled trials enrolled 16 037 patients with sepsis, critical illness, stroke, trauma, myocardial infarction, or cardiac arrest, and patients who had emergency surgery. Compared with a conservative oxygen strategy, a liberal oxygen strategy (median baseline saturation of peripheral oxygen SpO2 across trials, 96% range 94–99%, IQR 96–98) increased mortality in-hospital (relative risk RR 1·21, 95% CI 1·03–1·43, I2=0%, high quality), at 30 days (RR 1·14, 95% CI 1·01–1·29, I2=0%, high quality), and at longest follow-up (RR 1·10, 95% CI 1·00–1·20, I2=0%, high quality). Morbidity outcomes were similar between groups. Findings were robust to trial sequential, subgroup, and sensitivity analyses.
In acutely ill adults, high-quality evidence shows that liberal oxygen therapy increases mortality without improving other patient-important outcomes. Supplemental oxygen might become unfavourable above an SpO2 range of 94–96%. These results support the conservative administration of oxygen therapy.
None.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The sensitivity for singlet oxygen (1O2) of two convenient 1O2 probes, 1,3-diphenylisobenzofuran (DPBF) and 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA), has been investigated in different ...aqueous environments. Both probes are commercially available at reasonable cost and can be used with standard UV–vis spectrometers. Although DPBF is not soluble in neat water and is not specific to the detection of 1O2, it has very high, essentially diffusion-limited, reactivity towards 1O2; it can trap up to 50% of all 1O2 created in alcohol/water or micellar solution, and even more when replacing H2O by D2O, which makes it highly useful when the process under investigation does not yield much 1O2. On the other hand, ABDA has a much lower reactivity, reacting with only 2% of the singlet oxygen generated in H2O, as well as a smaller extinction coefficient, resulting in a much smaller spectroscopic response, but is soluble in neat water and is specific for 1O2, allowing for discrimination from other reactive oxygen species. The results presented here not only allow a comparative assessment of the usefulness of the two 1O2 probes, but also provide a reference for an accurate absolute quantification of the amount of 1O2 generated in an experiment from the observed absorbance bleach.
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•Two commercially available probes for singlet oxygen have been compared.•Reactivity of DPBF with singlet oxygen is diffusion-limited in ethanol/water.•ABDA is much less sensitive than DPBF, but is specific to singlet oxygen.•Quantitative results provide calibration for determining singlet oxygen yields.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Summary
High‐flow nasal oxygen used before and during apnoea prolongs time to desaturation at induction of anaesthesia. It is unclear how much oxygenation before apnoea prolongs this time. We ...randomly allocated 84 participants to 3 minutes of pre‐oxygenation by one of three methods: 15 l.min‐1 by facemask; 50 l.min‐1 by high‐flow nasal cannulae only; or 50 l.min‐1 by high‐flow nasal cannulae plus 15 l.min‐1 by mouthpiece. We then anaesthetised and intubated the trachea of 79 participants and waited for oxygen saturation to fall to 92%. Median (IQR range) times to desaturate to 92% after pre‐oxygenation with facemask oxygen, high‐flow nasal oxygen only and high‐flow nasal oxygen with mouthpiece, were: 309 (208‐417 107‐544) s; 344 (250‐393 194‐585) s; and 386 (328‐498 182‐852) s, respectively, p = 0.014. Time to desaturation after facemask pre‐oxygenation was shorter than after combined nasal and mouthpiece pre‐oxygenation, p = 0.006. We could not statistically distinguish high‐flow nasal oxygen without mouthpiece from the other two groups for this outcome. Median (IQR range) arterial oxygen partial pressure after 3 minutes of pre‐oxygenation by facemask, nasal cannulae and nasal cannulae plus mouthpiece, was: 49 (36‐61 24‐66) kPa; 57 (48‐62 30‐69) kPa; and 61 (55‐64 36‐72) kPa, respectively, p = 0.003. Oxygen partial pressure after 3 minutes of pre‐oxygenation with nasal and mouthpiece combination was greater than after facemask pre‐oxygenation, p = 0.002, and after high‐flow nasal oxygen alone, p = 0.016. We did not reject the null hypothesis for the pairwise comparison of facemask pre‐oxygenation and high‐flow nasal pre‐oxygenation, p = 0.14.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Metal–nitrogen–carbon (M–N–C) materials have attracted much interest in bifunctional oxygen‐involving electrocatalysis for rechargeable Zn–air batteries. Such M–N–C electrocatalysts with M–Nx sites ...show good activity for the oxygen reduction reaction (ORR) but moderate activity for the oxygen evolution reaction (OER). Herein, an oxygen‐rich M–N–C material (O–Co–N/C) with a highly porous nanosheet structure is reported as a bifunctional oxygen electrocatalyst, which is prepared by the direct pyrolysis of ultrathin CoO nanosheets decorated with zeolitic imidazolate framework‐8 nanoparticles under an inert atmosphere. Particularly, Co nanoparticles in the O–Co–N/C electrocatalyst contain both Co–Nx and Co–Ox coordination environments to provide intrinsic active sites for the ORR and OER, respectively. Furthermore, electrochemical studies show that the O–Co–N/C catalyst retains comparable ORR activity to common M–N–C materials with a half‐wave potential of 0.85 V vs the reversible hydrogen electrode and better OER activity with an overpotential of 0.29 V at the current density of 10 mA cm−2. This study provides insights into the development of effective oxygen‐involving electrocatalysts with bifunctional metal active centers coordinated by both nitrogen and oxygen atoms.
In oxygen‐rich cobalt–nitrogen–carbon porous nanosheets, the Co–Nx and Co–Ox units consisting of cobalt centers coordinated with nitrogen and oxygen atoms act as the intrinsic oxygen reduction and oxygen evolution active sites, respectively, for bifunctional oxygen electrocatalysis and rechargeable Zn–air batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Developing robust oxygen evolution reaction (OER) catalysts requires significant advances in material design and in‐depth understanding for water electrolysis. Herein, we report iridium clusters ...stabilized surface reconstructed oxyhydroxides on amorphous metal borides array, achieving an ultralow overpotential of 178 mV at 10 mA cm−2 for OER in alkaline medium. The coupling of iridium clusters induced the formation of high valence cobalt species and Ir–O–Co bridge between iridium and oxyhydroxides at the atomic scale, engineering lattice oxygen activation and non‐concerted proton‐electron transfer to trigger multiple active sites for intrinsic pH‐dependent OER activity. The lattice oxygen oxidation mechanism (LOM) was confirmed by in situ 18O isotope labeling mass spectrometry and chemical recognition of negative peroxo‐like species. Theoretical simulations reveal that the OER performance on this catalyst is intrinsically dominated by LOM pathway, facilitating the reaction kinetics. This work not only paves an avenue for the rational design of electrocatalysts, but also serves the fundamental insights into the lattice oxygen participation for promising OER application.
Iridium clusters stabilized surface reconstructed oxyhydroxides on an amorphous metal boride array are reported, achieving an ultralow overpotential of 178 mV at 10 mA cm−2 for OER in alkaline medium. The coupling of iridium clusters induces the formation of high‐valence cobalt species and Ir–O–Co bridges between iridium and oxyhydroxides at the atomic scale.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Hypoxia of solid tumor compromises the therapeutic outcome of photodynamic therapy (PDT) that relies on localized O
molecules to produce highly cytotoxic singlet oxygen (
O
) species. Herein, we ...present a safe and versatile self-assembled PDT nanoagent, i.e., OxgeMCC-r single-atom enzyme (SAE), consisting of single-atom ruthenium as the active catalytic site anchored in a metal-organic framework Mn
Co(CN)
with encapsulated chlorin e6 (Ce6), which serves as a catalase-like nanozyme for oxygen generation. Coordination-driven self-assembly of organic linkers and metal ions in the presence of a biocompatible polymer generates a nanoscale network that adaptively encapsulates Ce6. The resulted OxgeMCC-r SAE possesses well-defined morphology, uniform size distribution and high loading capacity. When conducting the in situ O
generation through the reaction between endogenous H
O
and single-atom Ru species of OxgeMCC-r SAE, the hypoxia in tumor microenvironment is relieved. Our study demonstrates a promising self-assembled nanozyme with highly efficient single-atom catalytic sites for cancer treatment.
Summary
Whether high‐flow vs. low‐flow nasal oxygen reduces hypoxaemia for sedation during endoscopic retrograde cholangiopancreatography is currently unknown. In this multicentre trial, 132 patients ...ASA physical status 3 or higher, BMI > 30 kg.m‐2 or with known or suspected obstructive sleep apnoea were randomly allocated to high‐flow nasal oxygen up to 60 l.min‐1 at 100% FIO2 or low‐flow nasal oxygen at 4 l.min‐1. The low‐flow nasal oxygen group also received oxygen at 4 l.min‐1 through an oxygenating mouthguard, totalling 8 l.min‐1. Primary outcome was hypoxaemia, defined as SpO2 < 90% regardless of duration. Hypoxaemia occurred in 7.7% (5/65) of patients with high‐flow and 9.1% (6/66) with low‐flow nasal oxygen (percentage point difference −1.4%, 95%CI −10.9 to 8.0; p = 0.77). Between the groups, there were no significant differences in frequency of hypoxaemic episodes; lowest SpO2; peak transcutaneous carbon dioxide; hypercarbia (transcutaneous carbon dioxide > 2.66 kPa from baseline); requirement of chin lift/jaw thrust; nasopharyngeal airway insertion; bag‐mask ventilation; or tracheal intubation. Following adjustment for duration of the procedure, the primary outcome remained non‐significant. In high‐risk patients undergoing endoscopic retrograde cholangiopancreatography, oxygen therapy with high‐flow nasal oxygen did not reduce the rate of hypoxaemia, hypercarbia or the need for airway interventions, compared with combined oral and nasal low‐flow oxygen.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Even though supplemental oxygen is used for the treatment of patients with hypoxemic respiratory failure, the most effective oxygenation targets are not known. In this randomized trial, a lower ...oxygenation target did not result in lower mortality than a higher target.
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