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Prajakta Rajaram Parab, K Alexander Heufer, Ravi Xavier Fernandes
Isopentanol is a potential next-generation biofuel for future applications to Homogeneous Charge Compression Ignition (HCCI) engine concepts. To provide insights into the combustion behavior of isopentanol, especially to its auto-ignition behavior which is linked both to efficiency and pollutant formation in real combustion systems, detailed quantum chemical studies for crucial reactions are desired. H-Abstraction reaction rates from fuel molecules are key initiation steps for chain branching required for auto-ignition...
March 13, 2018: Physical Chemistry Chemical Physics: PCCP
Tianlei Zhang, Xinguang Lan, Zhangyu Qiao, Rui Wang, Xiaohu Yu, Qiong Xu, Zhiyin Wang, Linxia Jin, ZhuQing Wang
To study the catalytic effects of (H2 O)n (n = 1-3), the mechanisms of the reaction HO2 + HO →3 O2 + H2 O without and with (H2 O)n (n = 1-3) have been investigated theoretically at the CCSD(T)/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ level of theory, coupled with rate constant calculations using the conventional transition state theory. Our results show that upon incorporation of (H2 O)n (n = 1-3) into the channel of H2 O +3 O2 formation, two different reactions, i.e. HO + HO2 (H2 O)n (n = 1-3) and HO2 + HO(H2 O)n (n = 1-3), have been observed, and these two reactions are competitive with each other...
March 9, 2018: Physical Chemistry Chemical Physics: PCCP
Sergey Valer'evich Panteleev, Artem E Masunov, Subith S Vasu
The kinetics of reaction CH3 + HO2 -> CH3O + OH in supercritical carbon dioxide media at pressures from 0.3 to 1000 atm in the temperature range (600-1600) K was studied using boxed molecular dynamics simulations at QM/MM theory level with periodical boundary conditions. The mechanism of this process includes two consecutive steps: formation and decomposition of CH3OOH intermediate. We calculated the activation free energies and rate constants of each step, then used Bodenstein's quasistationary concentrations approximation to estimate the rate constants of the reaction...
March 5, 2018: Journal of Physical Chemistry. A
Faiz Ur Rahman, Dae-Ryoung Park, Yeonsoo Joe, Kyu Yun Jang, Hun Taeg Chung, Uh-Hyun Kim
AIMS: Glucagon-like peptide-1 (GLP-1) increases intracellular Ca2+ concentrations, resulting in insulin secretion from pancreatic β-cells through the sequential production of Ca2+ mobilizing messengers nicotinic acid adenine dinucleotide phosphate (NAADP) and cyclic ADP-ribose (cADPR). We previously found that NAADP activates the neuronal type of nitric oxide (NO) synthase (nNOS), which product, NO, activates guanylyl cyclase (GC) to produce cyclic GMP (cGMP), which in turn induces cADPR formation...
February 27, 2018: Antioxidants & Redox Signaling
Nanduri R Prabhakar, Ying-Jie Peng, Guoxiang Yuan, Jayasri Nanduri
Sleep apnea is a prevalent respiratory disease characterized by periodic cessation of breathing during sleep causing intermittent hypoxia (IH). Sleep apnea patients and rodents exposed to IH exhibit elevated sympathetic nerve activity and hypertension. A heightened carotid body (CB) chemoreflex has been implicated in causing autonomic abnormalities in IH-treated rodents and in sleep apnea patients. The purpose of this article is to review the emerging evidence showing that interactions between reactive oxygen species (ROS) and gaseous transmitters as a mechanism cause hyperactive CB by IH...
February 22, 2018: Cell and Tissue Research
Tam V-T Mai, Minh V Duong, Hieu T Nguyen, Lam K Huynh
The detailed kinetic mechanism of the HOSO2 +3 O2 reaction, which plays a pivotal role in the atmospheric oxidation of SO2 , was investigated using accurate electronic structure calculations and novel statistical thermodynamic/kinetic models. Explored using the accurate composite method W1U, the detailed potential energy surface (PES) revealed that the addition of O2 to a HOSO2 radical to form the adduct (HOSO4 ) proceeds via a transition state with a slightly positive barrier (i.e., 0.7 kcal mol-1 at 0 K)...
February 19, 2018: Physical Chemistry Chemical Physics: PCCP
Loredana Salerno, Emanuele Amata, Giuseppe Romeo, Agostino Marrazzo, Orazio Prezzavento, Giuseppe Floresta, Valeria Sorrenti, Ignazio Barbagallo, Antonio Rescifina, Valeria Pittalà
Here we report the design, synthesis, and molecular modeling of new potent and selective imidazole-based HO-1 inhibitors in which the imidazole nucleus and the hydrophobic groups are linked by a phenylethanolic spacer. Most of the tested compounds showed a good inhibitor activity with IC 50 values in the low micromolar range, with two of them (1b and 1j) exhibiting also high selectivity toward HO-2. These results were obtained by the idea of potholing the entire volume of the principal hydrophobic western region with an appropriate ligand volume...
February 9, 2018: European Journal of Medicinal Chemistry
Yi-Tai Chou, Fu-Fei Hsu, Dun-Yao Hu, Ying-Chih Chen, Yuan-Hao Hsu, John T-A Hsu, Lee-Young Chau
BACKGROUND: Heme oxygenase (HO) catalyzes NADPH-dependent degradation of heme to liberate iron, carbon monoxide and biliverdin. The interaction between HO and cytochrome P450 reductase (CPR), an electron donor, is essential for HO activity. HO-1 is a stress-inducible isoform whereas HO-2 is constitutively expressed. HO-1 induction is commonly seen in cancers and impacts disease progression, supporting the possibility of targeting HO-1 for cancer therapy. METHODS: We employed a cell-based bioluminescence resonance energy transfer assay to screen compounds with ability to inhibit HO-1/CPR interaction...
January 23, 2018: Journal of Biomedical Science
Moritz M Innmann, Katrin Spier, Marcus R Streit, Peter R Aldinger, Thomas Bruckner, Tobias Gotterbarm, Christian Merle
BACKGROUND: We questioned whether there was a radiographic difference in hip geometry reconstruction and implant fixation between 3 different cementless stem design concepts in patients with primary end-stage hip osteoarthritis. METHODS: We retrospectively evaluated the preoperative and postoperative radiographs by 2 independent and blinded reviewers in a series of 264 consecutive patients who had received either a straight double-tapered stem with 3 offset options (group A), a straight double-tapered stem with 2 shape options and modular necks (group B), and a bone-preserving curved tapered stem with 4 offset options (group C)...
November 21, 2017: Journal of Arthroplasty
Christiaan M Suttorp, Niels A Cremers, René van Rheden, Raymond F Regan, Pia Helmich, Sven van Kempen, Anne M Kuijpers-Jagtman, Frank A D T G Wagener
Disintegration of the midline epithelial seam (MES) is crucial for palatal fusion, and failure results in cleft palate. Palatal fusion and wound repair share many common signaling pathways related to epithelial-mesenchymal cross-talk. We postulate that chemokine CXCL11, its receptor CXCR3, and the cytoprotective enzyme heme oxygenase (HO), which are crucial during wound repair, also play a decisive role in MES disintegration. Fetal growth restriction and craniofacial abnormalities were present in HO-2 knockout (KO) mice without effects on palatal fusion...
2017: Frontiers in Cell and Developmental Biology
Bianca Schaefer, Kohji Moriishi, Soenke Behrends
It has recently been shown that signal peptide peptidase (SPP) can catalyze the intramembrane cleavage of heme oxygenase-1 (HO-1) that leads to translocation of HO-1 into the cytosol and nucleus. While there is consensus that translocated HO-1 promotes tumor progression and drug resistance, the physiological signals leading to SPP-mediated intramembrane cleavage of HO-1 and the specificity of the process remain unclear. In this study, we used co-immunoprecipitation and confocal laser scanning microscopy to investigate the translocation mechanism of HO-1 and its regulation by SPP...
2017: PloS One
Jing-Jing Deng, Qing Yuan, Man-Xia Wang, Yi-Zong Yang
OBJECTIVE: To observe the effect of acupuncture on expression of receptor tyrosine kinase (RTK) c-kit in interstitial cells of Cajal (ICCs), carbon monoxide (CO) and heme oxygenase (HO) in colon tissue after colonic anastomosis, so as to explore the mechanism of acupuncture in improving gastrointestinal motility. METHODS: SD rats were randomly devided into control group, model group and acupuncture group. The model was established using colonic anastomosis. Each group was further devided into 3, 5, and 10 d (time-point) subgroups (n=10 in each)...
August 25, 2017: Zhen Ci Yan Jiu, Acupuncture Research
David Němeček, Markéta Dvořáková, Ivona Heroutová, Eva Chmelíková, Markéta Sedmíková
If fertilization of matured oocyte does not occur, unfertilized oocyte undergoes aging, resulting in a time-dependent reduction of the oocyte's quality. The aging of porcine oocytes can lead to apoptosis. Carbon monoxide (CO), a signal molecule produced by the heme oxygenase (HO), possesses cytoprotective and anti-apoptotic effects that have been described in somatic cells. However, the effects of CO in oocytes have yet to be investigated. By immunocytochemistry method we detected that both isoforms of heme oxygenase (HO-1 and HO-2) are present in the porcine oocytes...
2017: PeerJ
Rafael Alves Cazuza, Olga Pol, Christie Ramos Andrade Leite-Panissi
Some researchers have shown that carbon monoxide (CO) plays a role in emotional behavior modulation through intracellular 3'-5'-guanosine monophosphate mechanisms in the locus coeruleus (LC). In fact, the LC region has a high expression of the heme-oxygenase (HO) enzymes, which are responsible for the production of CO. However, the physiological mechanism by which the HO-CO pathway participates in the modulation of emotional responses in the LC still needs clarification. This study evaluates whether a systemic intraperitoneal treatment is able to alter behavioral responses (in the elevated plus-maze and the light-dark box test) and the expression of the HO-1 and HO-2 enzymes in the LC...
January 15, 2018: Behavioural Brain Research
Maaike Hum, Brian E McLaughlin, Xianqi Kong, Jason Z Vlahakis, Dragic Vukomanovic, Walter A Szarek, Kanji Nakatsu
Metalloporphyrin heme oxygenase (HO) inhibitors have made an important contribution to elucidating the role of HO in physiological processes. Nevertheless, their off-target effects have drawn substantial criticism, which prompted us to develop non-porphyrin, azole-based inhibitors of HO. These second-generation HO inhibitors were evaluated using spleen and brain microsomes from rats as native sources of HO-1 and HO-2, respectively. Recently, the use of azole-based inhibitors of HO has been extended to other mammalian species and, as a consequence, it will be important to characterize the inhibitors in these species...
August 9, 2017: Canadian Journal of Physiology and Pharmacology
Anikó Posa, Renáta Szabó, Krisztina Kupai, Anikó Magyariné Berkó, Médea Veszelka, Gergő Szűcs, Denise Börzsei, Mariann Gyöngyösi, Imre Pávó, Zoltán Deim, Zoltán Szilvássy, Béla Juhász, Csaba Varga
Estrogens and raloxifene (RAL) have beneficial effects on certain cardiovascular indices in postmenopausal women characterized by estrogen deficiency. Heme oxygenase (HO) activity is increased by 17β-estradiol (E2) and RAL in estrogen-deficient rat resulting in vasorelaxation mediated by carbon monoxide. We determined the expressions of HO in cardiac and aortic tissues after ovariectomy (OVX) and subsequent RAL or E2 treatment. We investigated the effects of pharmacological inhibition of HO enzyme on the arginine vasopressin- (AVP-) induced blood pressure in vivo, the epinephrine- and phentolamine-induced electrocardiogram ST segment changes in vivo, and the myeloperoxidase (MPO) enzyme activity...
2017: Oxidative Medicine and Cellular Longevity
Shailendra P Singh, Ilana Grant, Aliza Meissner, Attallah Kappas, Nader G Abraham
Background Hmox1 plays an important role in the regulation of mitochondrial bioenergetics and function by regulating cellular heme-derived CO and bilirubin. Previous studies have demonstrated that global disruption of HO-1 in humans and mice resulted in severe organ dysfunction. Methods We investigated the potential role of adipose-specific-HO-1 genetic ablation on adipose tissue function, mitochondrial quality control and energy expenditure by generating an adipo-HO-1 knockout mouse model (Adipo-HO-1-/-) and, in vitro, adipocyte cells in which HO activity was inhibited...
August 1, 2017: Hormone Molecular Biology and Clinical Investigation
Emanuele Amata, Agostino Marrazzo, Maria Dichiara, Maria N Modica, Loredana Salerno, Orazio Prezzavento, Giovanni Nastasi, Antonio Rescifina, Giuseppe Romeo, Valeria Pittalà
Due to increasing interest in the field of heme oxygenases (HOs), we built a ligand database called HemeOxDB that includes the entire set of known HO-1 and HO-2 inhibitors, resulting in more than 400 compounds. The HemeOxDB is available online at, and having a robust search engine allows end users to build complex queries, sort tabulated results, and generate color-coded two- and three-dimensional graphs. This database will grow to be a tool for the design of potent and selective HO-1 or HO-2 inhibitors...
July 14, 2017: ChemMedChem
L D C Jaubert, T Lin, T S Opel, P C W Holdsworth, M J P Gingras
Motivated by recent realizations of Dy_{2}Ti_{2}O_{7} and Ho_{2}Ti_{2}O_{7} spin ice thin films, and more generally by the physics of confined gauge fields, we study a model spin ice thin film with surfaces perpendicular to the [001] cubic axis. The resulting open boundaries make half of the bonds on the interfaces inequivalent. By tuning the strength of these inequivalent "orphan" bonds, dipolar interactions induce a surface ordering equivalent to a two-dimensional crystallization of magnetic surface charges...
May 19, 2017: Physical Review Letters
Kangtao Tian, Fanxing Xu, Xiang Gao, Tong Han, Jia Li, Huaqi Pan, Linghe Zang, Dahong Li, Zhanlin Li, Takahiro Uchita, Ming Gao, Huiming Hua
A series of NO-donating mono- or diester derivatives of brefeldin A were designed, synthesized and biologically evaluated. Some derivatives exhibited potent antiproliferative activity with low IC50 values. The most potent NO-donating hybrid 13b exhibited stronger cytotoxicity against human prostate cancer PC-3 cells, human colon carcinoma HT-29 cells and human liver cancer HepG-2 cells than BFA with IC50 values of 25 nM, 160 nM and 180 nM, respectively. More importantly, compound 13b showed good selectivity between human normal and tumor liver cells with selectivity index of 33...
August 18, 2017: European Journal of Medicinal Chemistry
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