Mild Oxygen Research Articles

Effects of Exposure to Mild Hyperbaric Oxygen on DSS-Induced Colonic Inflammation and Diarrhea in Rats.

PurposeIn rodents, dextran sulfate sodium (DSS)-induced diarrhea and colonic inflammation have similar symptoms to those of ulcerative colitis in humans. We examined the effects of exposure to mild hyperbaric oxygen (MHO) at an atmospheric pressure of 1317 hPa with 40% oxygen on DSS-induced diarrhea and colonic inflammation in rats.MethodsFive-week-old male Kyoto Apc Delta (KAD) rats (n = 12) were administered 2% DSS through drinking water for 1 week. Subsequently, DSS-treated male rats were not subjected to any further treatment (n = 6) or exposed to MHO (n = 6) for 2 weeks. Age-matched KAD rats not subjected to DSS treatment or exposed to MHO were used as the control group (n = 6).ResultsControl rats did not exhibit diarrhea and colonic inflammation. However, DSS-treated rats exhibited diarrhea and colonic inflammation, regardless of exposure to MHO. Exposure to MHO for 2 weeks led to decreased incidence of diarrhea in DSS-treated rats (p < 0.05). Exposure to MHO had no effect on colonic inflammation in DSS-treated rats (p = 0.12).ConclusionExposure to MHO for 2 weeks can improve diarrhea but cannot attenuate colonic inflammation, possibly due to the short exposure duration (2 weeks) used in this study.

Lactate and pyruvate promote oxidative stress resistance through hormetic ROS signaling

L-lactate was long considered a glycolytic by-product but is now being recognized as a signaling molecule involved in cell survival. In this manuscript, we report the role of L-lactate in stress resistance and cell survival mechanisms using neuroblastoma cells (SH-SY5Y) as well as the C. elegans model. We observed that L-lactate promotes cellular defense mechanisms, including Unfolded Protein Response (UPR) and activation of nuclear factor erythroid 2–related factor 2 (NRF2), by promoting a mild Reactive Oxygen Species (ROS) burst. This increase in ROS triggers antioxidant defenses and pro-survival pathways, such as PI3K/AKT and Endoplasmic Reticulum (ER) chaperones. These results contribute to the understanding of the molecular mechanisms involved in beneficial effects of L-lactate, involving mild ROS burst, leading to activation of unfolded protein responses and detoxification mechanisms. We present evidence that this hormetic mechanism induced by L-lactate protects against oxidative stress in vitro and in vivo. This work contributes to the identification of molecular mechanisms, which could serve as targets for future therapeutic approaches for cell protection and aging-related disorders.

Mild Hyperoxia Stimulation Increases Regional Tissue Oxygen Pressure in Rat Hippocampus via Oxygen Radical

Aims: The purpose of this study is to examine a rise of the local tissue oxygen pressure in hippocampus (Hip-pO2) which means neuronal activation by mild hyperoxia through oxygen radical.&#x0D; Study Design: Study was an animal experiment with rat.&#x0D; Place and Duration of Study: Department of Department of Life Science and Applied Chemistry, Nagaya Institute of Technology, between January 2014 and January 2018.&#x0D; Methodology: Rats were exposed to air or mild oxygen gas. At the same time, Local tissue oxygen pressure in hippocampus (Hip-pO2) were measured for 20 min with or without treatment of two type of radical scavengers.&#x0D; Results: The Hip-pO2 levels were significantly increased by mild hyperoxia exposure (50-60% above resting level). The mild hyperoxia-induced enhancement of the Hip-pO2 levels were inhibited by MnTMPyP (radical scavenger), but not by NADPH oxidase (NOX) inhibitor Apocynin.&#x0D; Conclusion: These findings suggested that mild hyperoxia could activate hippocampus through generation of oxygen radicals.

Effects of exposure to mild hyperbaric oxygen during unloading on muscle properties in rats.

This study investigated the effects of exposure to mild hyperbaric oxygen during unloading on the properties of the soleus muscle in rats, because exposure to mild hyperbaric oxygen enhances oxidative metabolism in cells and tissues. Therefore, exposure to mild hyperbaric oxygen should inhibit the unloading-induced degenerative changes in skeletal muscles. One group of 7-week-old male Wistar rats were unloaded by hindlimb suspension for 2weeks (HU, n = 12). A second group of age-matched rats were exposed to mild hyperbaric oxygen at 1317hPa with 40% oxygen for 3h a day during hindlimb suspension (HU + MHO, n = 12). A third group of age-matched rats without hindlimb suspension and exposure to mild hyperbaric oxygen were assigned as the controls (WR, n = 12). Soleus muscle weight (per body weight), succinate dehydrogenase (SDH) activity, and peroxisome proliferator-activated receptor γ coactivator-1α (Pgc-1α) mRNA levels were lower in the HU and HU + MHO groups than in the WR group, and these were higher in the HU + MHO group than in the HU group. The unloading-induced type shift from type I to type IIA fibers was inhibited by exposure to mild hyperbaric oxygen during unloading. It is concluded that the unloading-induced decrease in soleus muscle weight (per body weight) and type shift from type I to type IIA fibers in the soleus muscle were partially inhibited by exposure to mild hyperbaric oxygen during unloading.

Computer-Assisted Propofol Sedation for Esophagogastroduodenoscopy Is Effective, Efficient, and Safe.

Computer-assisted propofol sedation (CAPS) allows non-anesthesiologists to administer propofol for gastrointestinal procedures in relatively healthy patients. As the first US medical center to adopt CAPS technology for routine clinical use, we report our 1-year experience with CAPS for esophagogastroduodenoscopy (EGD). Between September 2014 and August 2015, 926 outpatients underwent elective EGDs with CAPS at our center. All EGDs were performed by 1 of 17 gastroenterologists certified in the use of CAPS. Procedural success rates, procedure times, and recovery times were compared against corresponding historical controls done with midazolam and fentanyl sedation from September 2013 to August 2014. Adverse events in CAPS patients were recorded. The mean age of the CAPS cohort was 56.7years (45% male); 16.2% of the EGDs were for variceal screening or Barrett's surveillance and 83.8% for symptoms. The procedural success rates were similar to that of historical controls (99.0% vs. 99.3%; p = 0.532); procedure times were also similar (6.6 vs. 7.4min; p = 0.280), but recovery time was markedly shorter (31.7 vs. 52.4min; p < 0.001). There were 11 (1.2%) cases of mild transient oxygen desaturation (< 90%), 15 (1.6%) cases of marked agitation due to undersedation, and 1 case of asymptomatic hypotension. In addition, there were six (0.6%) patients with more pronounced desaturation episodes that required brief (< 1min) mask ventilation. There were no other serious adverse events. CAPS appears to be a safe, effective, and efficient means of providing sedation for EGD in healthy patients. Recovery times were much shorter than historical controls.

Changes in oxygen and carbon dioxide in the genesis of sleep bruxism: a mechanism study

PurposeRhythmic masticatory muscle activity (RMMA), a biomarker of sleep bruxism (SB), has been associated with mild hypoxia and/or big breaths in some adults with non-sleep-disordered breathing. The purpose of this study was to investigate that concurrent oxygen and carbon dioxide fluctuations are among the physiological variables that contribute to RMMA onset. MethodsTwelve subjects (5 female, 7 male, mean age: 43 ± 11) underwent polysomnography recording in a sleep laboratory. RMMA index and apnea-hypopnea index were calculated. Oxygen saturation (SpO2) was estimated by finger pulse oximeter and end-tidal CO2 (ETCO2) by nasal airflow cannula before and after RMMA onset. Given the expected response time delay between actual arterial hypoxemia and fingertip pulse detection, we adjusted the SpO2 desaturation onset to the onset of masseter muscle activity using a 17 s criterion based on ETCO2 shifts. ResultsSpO2 was slightly but significantly lower than at baseline (max: −0.6%) in the 6–4 s before RMMA onset and significantly higher in the 6–18 s after onset (0.9%; p < 0.05). Although ETCO2 before RMMA onset did not differ from baseline, it decreased at 8–10 s after onset (−1.7 mmHg: p < 0.05). No changes in SpO2 or ETCO2 in relation to RMMA onset reached a critical clinical threshold. ConclusionsThe mild transient hypoxia observed before RMMA onset was not associated with a change in ETCO2. The mild and brief oxygen fluctuations before RMMA onset may reflect a physiological response that seems to have little influence on SB genesis.

White Adipose Tissue Response of Obese Mice to Ambient Oxygen Restriction at Thermoneutrality: Response Markers Identified, but no WAT Inflammation.

Obesity is associated with white adipose tissue (WAT) hypoxia and inflammation. We aimed to test whether mild environmental oxygen restriction (OxR, 13% O2), imposing tissue hypoxia, triggers WAT inflammation in obese mice. Thirteen weeks diet-induced obese male adult C57BL/6JOlaHsd mice housed at thermoneutrality were exposed for five days to OxR versus normoxia. WAT and blood were isolated and used for analysis of metabolites and adipokines, WAT histology and macrophage staining, and WAT transcriptomics. OxR increased circulating levels of haemoglobin and haematocrit as well as hypoxia responsive transcripts in WAT and decreased blood glucose, indicating systemic and tissue hypoxia. WAT aconitase activity was inhibited. Macrophage infiltration as marker for WAT inflammation tended to be decreased, which was supported by down regulation of inflammatory genes S100a8, Ccl8, Clec9a, Saa3, Mgst2, and Saa1. Other down regulated processes include cytoskeleton remodelling and metabolism, while response to hypoxia appeared most prominently up regulated. The adipokines coiled-coil domain containing 3 (CCDC3) and adiponectin, as well as the putative WAT hormone cholecystokinin (CCK), were reduced by OxR on transcript (Cck, Ccdc3) and/or serum protein level (adiponectin, CCDC3). Conclusively, our data demonstrate that also in obese mice OxR does not trigger WAT inflammation. However, OxR does evoke a metabolic response in WAT, with CCDC3 and adiponectin as potential markers for systemic or WAT hypoxia.

Relationship between mild seasonal oxygen deficiency and seasonal variations of macrozoobenthic community: A case study in the Yangtze River estuary and its adjacent area, China

In the present study, environmental parameters and macrozoobenthos in the Yangtze River estuary and its adjacent area, China, were investigated in summer and winter of 2015, and significant seasonal differences were found. Biodiversity was found to be lower in summer, which may result from the higher deposition rate. The relationship between the macrozoobenthic community and environmental parameters (especially dissolved oxygen) was revealed. Linear models describing the response of macrozoobenthic biodiversity indexes to mild oxygen deficiency were constructed. Mild seasonal oxygen deficiency was revealed significantly related to seasonal variations of the macrozoobenthic community, but this deficiency could not damage the community. In contrast, when mild oxygen deficiency occurred, natural predators of macrozoobenthos decreased, which may relieve the survival pressure of macrozoobenthos to some extent. Dissolved oxygen alone could not explain many variations of macrozoobenthos, and other environmental parameters, especially water depth, phosphate concentration and turbidity, also greatly contributed to those variations.

Mild hyperbaric oxygen: mechanisms and effects.

Adequate oxygen supply by exposure to mild hyperbaric oxygen at appropriately high atmospheric pressure (1266-1317hPa) and increased oxygen concentration (35-40% oxygen) has a possibility of improving the oxidative metabolism in cells and tissues without barotrauma and excessive production of reactive oxygen species. Therefore, metabolic syndrome and lifestyle-related diseases, including type 2 diabetes and hypertension, in rats were inhibited and/or improved by exposure to mild hyperbaric oxygen. It accelerated the growth-induced increase in oxidative capacity of the skeletal muscle in rats and inhibited the age-related decrease in oxidative capacity of the skeletal muscle in mice. A decrease in dopaminergic neurons in the substantia nigra of mice with Parkinson's disease was inhibited by exposure to mild hyperbaric oxygen. This review describes the beneficial effects of exposure to mild hyperbaric oxygen on some metabolic diseases and their perspectives.

Hydrogen Gas Inhalation Alleviates Radiation-Induced Bone Marrow Damage in Cancer Patients

Background: Radiotherapy for cancer patients is one of the useful methods; however, it not only impairs the targeted tumor tissues but also damage the normal surrounding tissues. Intensity modulated radiation therapy (IMRT) for cancer patients has been recently performed to alleviate the adverse effects, but reducing bone marrow damage is limited in the patients with multiple tumor lesions and large irradiation volume. Molecular hydrogen (H2) was recently reported as a preventive and therapeutic antioxidant that selectively scavenges hydroxy radical (*OH) and peroxynitrite (ONOO-). This observational study aims to examine whether H2 gas treatment improves IMRT radiation-induced bone marrow damage in cancer patients. Methods: The patients with end stage of cancer were received IMRT once per day for 1 to 4 weeks except Saturday and Sunday. After each IMRT, the patients of control group (n = 7) were housed in health care chamber (HCC, mild hyperbaric oxygen chamber) for 30 minutes, and the patients of H2 group (n = 16) were also housed in HCC and received 5% H2 gas for 30 minutes once per day. Radiation-induced bone marrow damage was evaluated by hematological examination of peripheral blood obtained before and after IMRT. Results: IMRT with HCC therapy significantly reduced white blood cells (WBC) and platelets (PLT) respectively, but not red blood cells (RBC), hemoglobin (HGB) and hematocrit (HT). In contrast, H2 gas treatment significantly alleviates reducing effects of WBC and PLT respectively. There was no difference in anti-tumor effects between the two groups. Interpretation: Our study demonstrated that H2 gas inhalation therapy significantly alleviates IMRT radiation-induced bone marrow damage without compromising anti-tumor effects. These results suggest that H2 gas treatment would be a strategy for reducing IMRT bone marrow damage in cancer patients. Funding: Self-funding. Declaration of Interest: NI and ST are supported by a grant from MiZ Company Limed. The other authors declare that they have no competing interests. Ethical Approval: The study protocol and materials were approved by ethics committee review by ICVS Tokyo Clinic (Tokyo, Japan), and all subjects provided written informed consent prior to the therapy.

A new post-synthetic polymerization strategy makes metal-organic frameworks more stable.

Metal-organic frameworks are of interest in a number of host-guest applications. However, their weak coordination bonding often leads to instability in aqueous environments, particularly at extreme pH, and hence, is a challenging topic in the field. In this work, a two-step, post-synthetic polymerization method is used to create a series of highly hydrophobic, stable MOF composites. The MOFs are first coated with thin layers of polydopamine from free-base dopamine under a mild oxygen atmosphere, which then undergoes a Michael addition to covalently graft hydrophobic molecules to the external MOF surface. This easy, mild post-synthetic modification is shown to significantly improve the stability of a number of structurally diverse MOFs including HKUST-1 (Cu), ZIF-67 (Co), ZIF-8 (Zn), UiO-66 (Zr), Cu-TDPAT (Cu), Mg-MOF-74 (Mg) and MIL-100 (Fe) in wet, caustic (acidic and basic) environments as determined by powder X-ray diffraction and surface area measurements.

Synthetic and mechanistic investigations on manganese corrole-catalyzed oxidation of sulfides with iodobenzene diacetate

Manganese corrole complexes catalyze the efficient oxidation of organic sulfides to sulfoxides with iodobenzene diacetate [PhI(OAc)2] as a mild oxygen source in the presence of small amounts of water. Various substituted thioanisoles can be efficiently oxidized to sulfoxides with quantitative conversions (up to 2500 TONs) and excellent selectivies for sulfoxides. The catalyst effects, including the corrole ligands and oxidation states of the central manganese, were investigated, and showed a significant impact on the catalytic sulfoxidations. The previously known high-valent manganese(V)-oxo corroles were chemically generated and kinetically studied in the oxidation of thioanisole substrates. The competition results suggested the oxidation state of manganese metal is crucial to control the nature of active oxidant forms that significantly affected their catalytic activity.

Effect of mild hyperbaric oxygen therapy on children diagnosed with autism

Introduction: Hyperbaric oxygen (HBO2) therapy is emerging internationally as the primary treatment modality for inflammatory pathways related to neurological disorders. Currently, literature concerning its effectiveness in autistic children is limited. Using neurocognitive tests and clinical-diagnostic evaluations, this study evaluates the clinical, cognitive and behavioral effects of HBO2 on children diagnosed with autism. Methods: An experimental HBO2 group (EXP: F = 1; M = 7; mean age: 7 ± 2.33; years) and a control non-HBO2 group of autistic children (CTRL: F = 2; M= 5; mean age: 6.6 ± 2.7 years) correctly completed the Aberrant Behavior Checklist-Community (ABC) before HBO2 (T0), after 40 sessions of HBO2 (T1), and one month after the end of treatments (T2). Additionally, the experimental HBO2 group was evaluated with the Childhood Autism Rating Scale at T0 and T2. Results: Total ABC score was lower at T2 (mean ± SD: 50.38 ± 18.55; p &lt; 0.001) compared to scores obtained at T0 (mean ± SD: 57.5 ± 19.01). Similarly, in the control group the total ABC score differed statistically (p &lt; 0.05) between T0 (103.6 ± 20.38) and (T2: 59 ± 25.25). Conclusions: Despite the improvements reported in both groups, our results do not support the utility of HBO2 in children diagnosed with autism.

Extracorporeal membrane oxygenation support in a newborn with lower urinary tract obstruction and pulmonary hypoplasia: a case report

BackgroundSurvival of neonates with intrauterine renal insufficiency and oligo- or anhydramnios correlates with the severity of secondary pulmonary hypoplasia. Early prenatal diagnosis together with repetitive amnioinfusions and modern intensive care treatment have improved the prognosis of these neonates. Extracorporeal membrane oxygenation is an established treatment option, mainly applied to neonates with pulmonary hypoplasia caused by congenital diaphragmatic hernia. However, a few case reports of extracorporeal membrane oxygenation in neonates with lower urinary tract obstruction have been published.Case presentationWe describe a case of a Caucasian male infant with prenatally diagnosed lower urinary tract obstruction and secondary pulmonary hypoplasia who was delivered spontaneously at 36 + 2 weeks of gestation. Venovenous extracorporeal membrane oxygenation was initiated on the first day of life for severe respiratory failure and consecutive hypoxemia despite treatment with inhaled nitric oxide and high-frequency oscillation. The patient was supported by extracorporeal membrane oxygenation for 10 days and extubated 6 weeks later. Hemofiltration was required on the second day of life because of renal insufficiency and was later replaced by peritoneal dialysis. The child was discharged after 4 months with nasal high-flow mild oxygen therapy and peritoneal dialysis.ConclusionNeonatal extracorporeal membrane oxygenation support is a possible treatment option for neonates with lower urinary tract obstruction and pulmonary hypoplasia.

Producing air-stable InSe nanosheet through mild oxygen plasma treatment

Ultrathin indium selenide (InSe), as a newly emerging two-dimensional material with high carrier mobility and broadband optical absorption, is considered as a promising candidate for electronic and optoelectronic devices. It has been a challenge to produce air-stable mono- or few-layer InSe nanosheets because they degrade rapidly in an ambient environment. Here, we demonstrate a facile mild oxygen plasma treatment route to fabricate air-stable few-layer InSe samples. Photoluminescence (PL) and x-ray photoelectron spectroscopy (XPS) analysis indicate that the plasma treatment can introduce an oxidation process that forms a dense InSe1−xOx capping layer on the surface, and thus prevent the sample from degradation. Furthermore, the oxide layer would introduce a PL quenching of the pristine InSe, while a new and strong PL peak belonging to the emission from InSe1−xOx appears. This work offers a practical and efficient route to improve the performance of InSe based electrical and optoelectronic devices.

Mild hyperbaric oxygen activates the proliferation of epidermal basal cells in aged mice.

The proliferation of epidermal basal cells decreases with age. This study examined the effects of exposure to mild hyperbaric oxygen on the proliferative activity of epidermal basal cells in aged mouse skin. Hairless mice aged 5, 34 and 55 weeks were exposed to mild hyperbaric oxygen at 1266 hPa with 36% oxygen for 6 h/day for 1 or 2 weeks. Skin samples were then collected from the back area to evaluate epidermal thickness and the number and proliferative activity of epidermal basal cells. Exposure to mild hyperbaric oxygen had no effect on the epidermal thickness, irrespective of age, but accelerated the proliferative activity of epidermal basal cells in aged mouse skin.

Mild hyperbaric oxygen inhibits the growth-related decline in skeletal muscle oxidative capacity and prevents hyperglycemia in rats with type 2 diabetes mellitus.

Humans and animals with type 2 diabetes mellitus (T2DM) exhibit low skeletal muscle oxidative capacity and impaired glucose metabolism. The aim of the present study was to investigate the effects of exposure to mild hyperbaric oxygen on these changes in obese rats with T2DM. Five-week-old non-diabetic Long-Evans Tokushima Otsuka (LETO) and diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats were divided into normobaric (LETO-NB and OLETF-NB) and mild hyperbaric oxygen (LETO-MHO and OLETF-MHO) groups. The LETO-MHO and OLETF-MHO groups received 1266 hPa with 36% oxygen for 3 h daily for 22 weeks. Fasting and non-fasting blood glucose, HbA1c, and triglyceride levels were lower in the OLETF-MHO group than in the OLETF-NB group (P < 0.05). In the soleus muscle, peroxisome proliferator-activated receptor δ/β (Pparδ/β), Pparγ, and PPARγ coactivator-1α (Pgc-1α) mRNA levels were lower in the OLETF-NB group than in all other groups (P < 0.05), whereas myogenin (Myog) and myogenic factor 5 (Myf5) mRNA levels were higher in the OLETF-MHO group than in the LETO-NB and OLETF-NB groups (P < 0.05). The soleus muscles in the OLETF-NB group contained only low-oxidative Type I fibers, whereas those in all other groups contained high-oxidative Type IIA and Type IIC fibers in addition to Type I fibers. Exposure to mild hyperbaric oxygen inhibits the decline in skeletal muscle oxidative capacity and prevents the hyperglycemia associated with T2DM. Pgc-1α, Myog, and Myf5 mRNA levels appear to be closely associated with skeletal muscle oxidative capacity in rats with T2DM.

Clinical and economic burden of procedural sedation-related adverse events and their outcomes: analysis from five countries.

BackgroundStudies have reported on the incidence of sedation-related adverse events (AEs), but little is known about their impact on health care costs and resource use.MethodsHealth care providers and payers in five countries were recruited for an online survey by independent administrators to ensure that investigators and respondents were blinded to each other. Surveys were conducted in the local language and began with a “screener” to ensure that respondents had relevant expertise and experience. Responses were analyzed using Excel and R, with the Dixon’s Q statistic used to identify and remove outliers. Global and country-specific average treatment patterns were calculated via bootstrapping; costs were mean values. The sum product of costs and intervention probability gave a cost per AE.ResultsResponses were received from 101 providers and 26 payers, the majority having >5 years of experience. At a minimum, the respondents performed a total of 3,430 procedural sedations per month. All AEs detailed occurred in clinical practice in the last year and were reported to cause procedural delays and cancellations in some patients. Standard procedural sedation costs ranged from €74 (Germany) to $2,300 (US). Respondents estimated that AEs would increase costs by between 16% (Italy) and 179% (US). Hypotension was reported as the most commonly observed AE with an associated global mean cost (interquartile range) of $43 ($27–$68). Other frequent AEs, including mild hypotension, bradycardia, tachycardia, mild oxygen desaturation, hypertension, and brief apnea, were estimated to increase health care spending on procedural sedation by $2.2 billion annually in the US.ConclusionAll sedation-related AEs can increase health care costs and result in substantial delays or cancellations of subsequent procedures. The prevention of even minor AEs during procedural sedation may be crucial to ensuring its value as a health care service.

Lewis Acid Catalyzed Conversion of 5-Hydroxymethylfurfural to 1,2,4-Benzenetriol, an Overlooked Biobased Compound.

5-Hydroxymethylfurfural (HMF) is a platform chemical that can be produced from renewable carbohydrate sources. HMF can be converted to 1,2,4-benzenetriol (BTO) which after catalytic hydrodeoxygenation provides a route to cyclohexanone and cyclohexanol. This mixture, known as KA oil, is an important feedstock for polymeric products such as nylons which use benzene as feedstock that is obtained from the BTX fraction produced in oil refineries. Therefore, the conversion of HMF to BTO provides a renewable, alternative route toward products such as nylons. However, BTO is usually considered an undesired byproduct in HMF synthesis and is only obtained in small amounts. Here, we show that Lewis acid catalysts can be utilized for the selective conversion of HMF to BTO in subsuper critical water. Overall, up to 54 mol % yield of BTO was achieved at 89% HMF conversion using ZnCl2. ZnCl2 and similarly effective Zn(OTf)2 and Fe(OTf)2 are known as relatively soft Lewis acids. Other Lewis acid like Hf(OTf)4 and Sc(OTf)3 gave increased selectivity toward levulinic acid (up to 33 mol %) instead of BTO, a well-known HMF derivative typically obtained by acid catalysis. Catalytic hydrodeoxygenation of BTO toward cyclohexanone in water was achieved in up to 45% yield using 5 wt % Pd on Al2O3 combined with AlCl3 or Al(OTf)3 as catalysts. Additionally, a mild selective oxygen induced dimerization pathway of BTO to 2,2′,4,4′,5,5′-hexahydroxybiphenyl (5,5′-BTO dimer) was identified.

Potential vulnerability of oak forests to climate change-induced flooding: effects of mild oxygen deficiency on Quercus robur and Quercus petraea seedling physiology.

Flooding is characterized by saturation of soil pores with water, leading to hypoxic conditions which affect plant root development and metabolism. We investigated the oxygen deficiency tolerance observed in Quercus robur and Quercus petraea and seek to understand whether it can be explained by enhanced efficiency in oxygen use in the roots, as estimated through radial oxygen loss visualization in relation to growth measurements and root apex respiration. The study showed that root growth, under oxygen deficiency conditions, was significantly reduced only in Q. robur seedlings. Root respiration was maintained in Q. robur, whereas it was decreased in Q. petraea. Both species set up a barrier against radial oxygen loss, though measurement of apex oxygen leakage showed greater oxygen efficiency in Q. robur seedlings. This strategy might allow Q. robur to maintain its respiration and thus to survive longer under oxygen deficiency conditions by facilitating the seedling establishment in transient flooded soils.