Role of Unstable Chemical Species (Non-Graphitic Carbon and Flowing NH3 Gas) on the Equilibrium Point of the Reaction Product (Carbide, Carbo-Nitride or Nitride)

ChemInform ◽  
2005 ◽  
Vol 36 (14) ◽  
Author(s):  
Nobumitsu Shohoji
Keyword(s):  
Equilibrium Point ◽  
Chemical Species ◽  
Graphitic Carbon

3D simulations of warm and hot Jupiter atmospheres: the role of 3D mixing in shaping CH4-to-CO conversion pathways

2021 ◽  
Author(s):  
Maria Zamyatina ◽  
Eric Hebrard ◽  
Nathan Mayne ◽  
Benjamin Drummond
Keyword(s):  
Chemical Structure ◽  
Three Dimensional ◽  
Chemical Species ◽  
Radiation Chemistry ◽  
3D Simulations ◽  
Horizontal Advection ◽  
Co Conversion ◽  
Area Of Influence ◽  
Different Parts

<p>We present results from a set of cloud-free simulations of exoplanet atmospheres using a coupled three-dimensional (3D) hydrodynamics-radiation-chemistry model. We report in particular our investigation of the thermodynamic and chemical structure of the atmospheres of HAT-P-11b and WASP-17b and their comparison with the results for the atmospheres of HD 189733b and HD 209458b presented in Drummond et al. (2020). We found that the abundances of chemical species from simulations with interactive chemistry depart from their respective abundances computed at local chemical equilibrium, especially at higher latitudes. To understand this departure, we analysed the CH<sub>4</sub>-to-CO conversion pathways within the Venot et al. (2019) reduced chemical network used in our model using a chemical network analysis. We found that at steady state nine CH<sub>4</sub>-to-CO conversion pathways manifest in our 3D simulations with interactive chemistry, with different pathways dominating different parts of the atmosphere and their area of influence being determined by the vertical and horizontal advection and shifting between planets.</p>

scholarly journals The Role of Oxidative Stress in Cardiac Disease: From Physiological Response to Injury Factor

2020 ◽  
Vol 2020 ◽  
pp. 1-29 ◽  
Author(s):  
Rossella D’Oria ◽  
Rossella Schipani ◽  
Anna Leonardini ◽  
Annalisa Natalicchio ◽  
Sebastio Perrini ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Myocardial Injury ◽  
Antioxidant Defense ◽  
Experimental Studies ◽  
Chemical Species ◽  
Oxygen Species ◽  
Molecular Abnormalities ◽  
Defense Systems ◽  
Antioxidant Defense Systems

Reactive oxygen species (ROS) are highly reactive chemical species containing oxygen, controlled by both enzymatic and nonenzymatic antioxidant defense systems. In the heart, ROS play an important role in cell homeostasis, by modulating cell proliferation, differentiation, and excitation-contraction coupling. Oxidative stress occurs when ROS production exceeds the buffering capacity of the antioxidant defense systems, leading to cellular and molecular abnormalities, ultimately resulting in cardiac dysfunction. In this review, we will discuss the physiological sources of ROS in the heart, the mechanisms of oxidative stress-related myocardial injury, and the implications of experimental studies and clinical trials with antioxidant therapies in cardiovascular diseases.

scholarly journals Characterization of a boreal convective boundary layer and its impact on atmospheric chemistry during HUMPPA-COPEC-2010

2012 ◽  
Vol 12 (19) ◽  
pp. 9335-9353 ◽  
Author(s):  
H. G. Ouwersloot ◽  
J. Vilà-Guerau de Arellano ◽  
A. C. Nölscher ◽  
M. C. Krol ◽  
L. N. Ganzeveld ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Chemistry ◽  
Convective Boundary Layer ◽  
Large Scale ◽  
Spatial Scales ◽  
Potential Temperature ◽  
Chemical Species ◽  
Convective Boundary ◽  
The Impact

Abstract. We studied the atmospheric boundary layer (ABL) dynamics and the impact on atmospheric chemistry during the HUMPPA-COPEC-2010 campaign. We used vertical profiles of potential temperature and specific moisture, obtained from 132 radio soundings, to determine the main boundary layer characteristics during the campaign. We propose a classification according to several main ABL prototypes. Further, we performed a case study of a single day, focusing on the convective boundary layer, to analyse the influence of the dynamics on the chemical evolution of the ABL. We used a mixed layer model, initialized and constrained by observations. In particular, we investigated the role of large scale atmospheric dynamics (subsidence and advection) on the ABL development and the evolution of chemical species concentrations. We find that, if the large scale forcings are taken into account, the ABL dynamics are represented satisfactorily. Subsequently, we studied the impact of mixing with a residual layer aloft during the morning transition on atmospheric chemistry. The time evolution of NOx and O3 concentrations, including morning peaks, can be explained and accurately simulated by incorporating the transition of the ABL dynamics from night to day. We demonstrate the importance of the ABL height evolution for the representation of atmospheric chemistry. Our findings underscore the need to couple the dynamics and chemistry at different spatial scales (from turbulence to mesoscale) in chemistry-transport models and in the interpretation of observational data.

scholarly journals The Role of Graphitic Carbon Nitride in the Formulation of Copper-Free Friction Composites Designed for Automotive Brake Pads

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 123
Author(s):  
Vlastimil Matějka ◽  
Mara Leonardi ◽  
Petr Praus ◽  
Giovanni Straffelini ◽  
Stefano Gialanella
Keyword(s):  
Carbon Nitride ◽  
Room Temperature ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Main Role ◽  
Brake Pads ◽  
Pin On Disc ◽  
Brake Lining ◽  
Automotive Brake

In this study, graphitic carbon nitride (g-C3N4, labelled as gCN) was tested in the formulation of copper-free (Cu-free) friction mixtures, which are potentially interesting for brake pad manufacturing. Three formulations of friction composites were prepared starting from a common Cu-free master batch: (i) without graphite, (ii) with graphite and (iii) with gCN. The mixtures were pressed in the form of pins by hot-press moulding. The friction-wear performance of the prepared pins was investigated using a pin-on-disc (PoD) test at room temperature (RT), high temperature (HT) (400 °C) and, again, at room temperature (H-RT). The values of the friction coefficient (µ) for the composites with gCN (or graphite) were as follows: (i) RT test, µRT = 0.52 (0.47); (ii) HT test, µHT = 0.37 (0.37); (iii) RT after the HT tests, µH-RT = 0.49 (0.39). With respect to wear resistance, the samples with graphite performed better than the samples without this solid lubricant. To the best of our knowledge, this is the first report regarding the evaluation of the role of gCN in friction composites designed for automotive brake lining applications. The results indicate the main role of gCN as a soft abrasive.

scholarly journals ROLE OF PHYTOCHEMICALS IN ORAL POTENTIALLY MALIGNANT DISORDERS : A REVIEW

2014 ◽  
Vol 04 (04) ◽  
pp. 120-125
Author(s):  
Ananya Madiyal ◽  
Vidya Ajila ◽  
Subhas G Babu ◽  
Shruthi Hedge ◽  
Harini Keshavaiah ◽  
...  
Keyword(s):  
Free Radicals ◽  
Chemical Species ◽  
Healthcare Services ◽  
Health Concern ◽  
Oral Lesions ◽  
Oral Potentially Malignant Disorders ◽  
Naturally Occurring ◽  
Potentially Malignant Disorders ◽  
Potentially Malignant

AbstractOral cancer is a major global health concern and poses a challenge to diagnostic and therapeutic aspects of healthcare services. Various oral lesions like leukoplakia, erythroplakia, lichen planus and oral submucus fibrosis categorized as orally potential malignant disorders have shown increased incidence of malignant transformation. Free radicals are highly reactive chemical species with capacity to damage nucleic acids, proteins and lipids and bring about changes of clinical significance. Antioxidants help in scavenging these free radicals and prevent disease progression. Naturally occurring phytochemicals play an important role in preventing oxidative stress and protect the cells from damage by free radicals.

Single-cell analyses of nitrergic neurons in simple nervous systems

1999 ◽  
Vol 202 (4) ◽  
pp. 333-341 ◽  
Author(s):  
L.L. Moroz ◽  
R. Gillette ◽  
J.V. Sweedler
Keyword(s):  
Single Cell ◽  
Cell Model ◽  
Single Cells ◽  
Chemical Species ◽  
No Oxidation ◽  
Cell Level ◽  
Pharmacological Manipulations ◽  
Physiological And Biochemical

Understanding the role of the gaseous messenger nitric oxide (NO) in the nervous system is complicated by the heterogeneity of its nerve cells; analyses carried out at the single cell level are therefore important, if not critical. Some invertebrate preparations, most especially those from the gastropod molluscs, provide large, hardy and identified neurons that are useful both for the development of analytical methodologies and for cellular analyses of NO metabolism and its actions. Recent modifications of capillary electrophoresis (CE) allow the use of a small fraction of an individual neuron to perform direct, quantitative and simultaneous assays of the major metabolites of the NO-citrulline cycle and associated biochemical pathways. These chemical species include the products of NO oxidation (NO2-/NO3-), l-arginine, l-citrulline, l-ornithine, l-argininosuccinate, as well as selected NO synthase inhibitors and cofactors such as NADPH, biopterin, FMN and FAD. Diverse cotransmitters can also be identified in the same nitrergic neuron. The sensitivity of CE methods is in the femtomole to attomole range, depending on the species analysed and on the specific detector used. CE analysis can be combined with prior in vivo electrophysiological and pharmacological manipulations and measurements to yield multiple physiological and biochemical values from single cells. The methodologies and instrumentation developed and tested using the convenient molluscan cell model can be adapted to the smaller and more delicate neurons of other invertebrates and chordates.

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