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In this article, we report a theoretical investigation on the role of several catalysts in the isomerisation mechanisms of HON(O)NNO2 to ON(OH)NNO2 by theoretical method of CBS-QB3. The isomerisation reactions with catalyst X (X = H2O, (H2O)2, HCOOH and H2SO4) are multi-hydrogen atom transfer reactions. Compared to the isomerisation mechanisms and rate constant of HON(O)NNO2 to ON(OH)NNO2 without catalysts, incorporation of the catalyst X shows different positive catalytic effects on affecting the reaction processes, with the H2SO4-assisted reaction being the most favourable. Such different catalytic effects are mainly related to the size of the ring structure in X-assisted transition states and the different values of pKa and proton affinities for HCOOH and H2SO4. Besides, compared with the barrier height of the isomerisation process from HON(O)NNO2 to ON(OH)NNO2 with HN(NO2)2 and HON(O)NNO2, the barrier of H2SO4-assisted reaction is lower by 9.3 and 4.5 kcal ·mol−1, meanwhile, the rate constant of H2SO4 catalyzed is larger than water and water dimer-assisted by 3-5 and 2-3 orders of magnitude, respectively. So, H2SO4-assisted reaction is the most favourable. [ABSTRACT FROM AUTHOR]

In this article, the isomerisation mechanisms of HN(NO2)2to O2NNN(O)OH without and with catalystX(X= H2O, (H2O)2, (H2O)3, HCOOH, H2SO4, CH3CH2COOH and HN(NO2)2) have been investigated theoretically at the CBS-QB3 level of theory. Our results show that the catalystX(X= H2O, (H2O)2, (H2O)3, HCOOH, H2SO4and CH3CH2COOH) shows different positive catalytic effects on reducing the apparent activation energy of the isomerisation reaction processes. Such different catalytic effects are mainly related to the number of hydrogen bonds and the size of the ring structure inX(X= H2O, (H2O)2and (H2O)3)-assisted transition states, as well as different values of pKafor H2SO4, HCOOH and CH3CH2COOH. Very interesting is also the fact that H2SO4-assisted reaction is the most favourable for the hydrogen transfer from HN(NO2)2to O2NNN(O)OH, due to the smallest pKa(−3.0) value of H2SO4than H2O, HCOOH, H2SO4and CH3CH2COOH, and also because of the largest ∠X•••H•••Y (the angle between the hydrogen bond donor and acceptor) involved in H2SO4-assisted transition state. Compared to the self-catalysis of the isomerisation mechanisms of HN(NO2)2to O2NNN(O)OH, the apparent activation energy of H2SO4-assisted channel also reduces by 9.6 kcal⋅mol−1, indicating that H2SO4can affect the isomerisation of HN(NO2)2to O2NNN(O)OH, most obvious among all the catalysts H2O, (H2O)2, (H2O)3, HCOOH, H2SO4, CH3CH2COOH and HN(NO2)2. [ABSTRACT FROM AUTHOR]

In this work, four different channels, represented by H2O•••HO2+ HOCl, HO2•••H2O + HOCl, H2O•••HOCl + HO2and HOCl•••H2O + HO2have been analysed for water-catalysed formations of H2O2+ ClO to gain insight into the potential impact of the reaction in the atmosphere. The results at the CCSD(T)/aug-cc-pVTZ//MP2/6-311+G(2df,2p) level show that the H2O•••HO2+ HOCl reaction is kinetically the most favourable channel among the four channels. Compared to the channel of H2O2+ ClO formations without water vapour, the effective rate constant of H2O•••HO2+ HOCl reaction is estimated to be faster than the naked reaction by 2–3 orders of magnitude, indicating that the single water molecule in the H2O•••HO2+ HOCl channel exhibits a positive catalytic effect on enhancing the rate of H2O2+ ClO formations. Meanwhile, it is interesting that the transfer process between H2O•••HOCl + HO2and H2O•••HO2+ HOCl has an activation energy of 0.6 kcal⋅mol−1and can occur easily under tropospheric conditions. [ABSTRACT FROM AUTHOR]

Hypoxic-ischemic encephalopathy, which predisposes to neonatal death and neurological sequelae, has a high morbidity, but there is still a lack of effective prevention and treatment in clinical practice. To better understand the pathophysiological mechanism underlying hypoxic-ischemic encephalopathy, in this study we compared hypoxic-ischemic reperfusion brain injury and simple hypoxic-ischemic brain injury in neonatal rats. First, based on the conventional Rice-Vannucci model of hypoxic-ischemic encephalopathy, we established a rat model of hypoxic-ischemic reperfusion brain injury by creating a common carotid artery muscle bridge. Then we performed tandem mass tag-based proteomic analysis to identify differentially expressed proteins between the hypoxic-ischemic reperfusion brain injury model and the conventional Rice-Vannucci model and found that the majority were mitochondrial proteins. We also performed transmission electron microscopy and found typical characteristics of ferroptosis, including mitochondrial shrinkage, ruptured mitochondrial membranes, and reduced or absent mitochondrial cristae. Further, both rat models showed high levels of glial fibrillary acidic protein and low levels of myelin basic protein, which are biological indicators of hypoxic-ischemic brain injury and indicate similar degrees of damage. Finally, we found that ferroptosis-related Ferritin (Fth1) and glutathione peroxidase 4 were expressed at higher levels in the brain tissue of rats with hypoxic-ischemic reperfusion brain injury than in rats with simple hypoxic-ischemic brain injury. Based on these results, it appears that the rat model of hypoxic-ischemic reperfusion brain injury is more closely related to the pathophysiology of clinical reperfusion. Reperfusion not only aggravates hypoxic-ischemic brain injury but also activates the anti-ferroptosis system., Competing Interests: None

Objectives: To study the application value of metagenomic next-generation sequencing (mNGS) in children with severe infectious diseases., Methods: An analysis was performed on the clinical data and laboratory test results of 29 children with severe infection who were admitted to the Second Affiliated Hospital of Wenzhou Medical University from June 2018 to December 2020. Conventional pathogen culture was performed for the 29 specimens (27 peripheral blood specimens and 2 pleural effusion specimens) from the 29 children, and mNGS pathogen detection was performed at the same time., Results: Among the 29 children, 2 tested positive by conventional pathogen culture with 2 strains of pathogen, and the detection rate was 7% (2/29); however, 20 children tested positive by mNGS with 38 strains of pathogen, and the detection rate was 69% (20/29). The pathogen detection rate of mNGS was significantly higher than that of conventional pathogen culture ( P <0.05), and mNGS could detect the viruses, fungi, and other special pathogens that conventional pathogen culture failed to detect, such as Orientia tsutsugamushi . The univariate analysis showed that gender, routine blood test results, C-reactive protein, procalcitonin, D-dimer, radiological findings, and whether antibiotics were used before admission did not affect the results of mNGS ( P >0.05)., Conclusions: Compared with conventional pathogen culture, mNGS is more sensitive for pathogen detection, with fewer interference factors. Therefore, it is a better pathogenic diagnosis method for severe infectious diseases in children.