scholarly journals Role of hydrogen ions in standard and activation heap leaching of gold

2017 ◽  
Vol 53 ◽  
pp. 012033
Author(s):  
YuI Rubtsov
Keyword(s):  
Heap Leaching ◽  
Hydrogen Ions

scholarly journals Metabolic Acidosis in Patients with CKD: Epidemiology, Pathogenesis, and Treatment

2021 ◽  
pp. 1-16
Author(s):  
Marcin Adamczak ◽  
Stanisław Surma
Keyword(s):  
Metabolic Acidosis ◽  
Sodium Bicarbonate ◽  
Current Knowledge ◽  
Venous Blood ◽  
The Body ◽  
Hydrogen Ions ◽  
Ckd Progression ◽  
New Drug ◽  
Treatment And Prevention

<b><i>Background:</i></b> Metabolic acidosis in CKD is diagnosed in patients with plasma or venous blood bicarbonate concentration lower than 22 mmol/L. Metabolic acidosis occurs in about 20% of patients with CKD. Metabolic acidosis may lead to dysfunction of many systems and organs as well as CKD progression. Currently, sodium bicarbonate is mainly used for pharmacological treatment of metabolic acidosis in patients with CKD. Veverimer is a new drug dedicated to treatment of metabolic acidosis in patients with CKD. Orally given veverimer binds hydrogen ions in the intestines and subsequently is excreted from the body with feces. Clinical studies have shown that veverimer is effective in increasing serum bicarbonate concentrations in CKD patients with metabolic acidosis. Here, we present review of the epidemiology, pathogenesis, diagnosis, treatment, and prevention of metabolic acidosis in CKD patients. <b><i>Summary:</i></b> Metabolic acidosis is common in patients with CKD and contributes to CKD progression and many complications, which worsen the prognosis in these patients. Currently, sodium bicarbonate is mainly used in metabolic acidosis treatment. The role of the new drug veverimer in the metabolic acidosis therapy needs further studies. <b><i>Key Message:</i></b> The aim of this review article is to summarize the current knowledge concerning the epidemiology, pathogenesis, diagnosis, treatment, and prevention of metabolic acidosis in CKD patients.

Alveolar hypercapnia augments pulmonary C-fiber responses to chemical stimulants: role of hydrogen ion

2002 ◽  
Vol 93 (1) ◽  
pp. 181-188 ◽  
Author(s):  
Qihai Gu ◽  
Lu-Yuan Lee
Keyword(s):  
Hydrogen Ion ◽  
Right Atrial ◽  
Mechanical Stimuli ◽  
Hydrogen Ions ◽  
Lung Inflation ◽  
C Fibers ◽  
Arterial Blood ◽  
Blood Ph ◽  
C Fiber

To determine whether the excitabilities of pulmonary C fibers to chemical and mechanical stimuli are altered by CO2-induced acidosis, single-unit pulmonary C-fiber activity was recorded in anesthetized, open-chest rats. Transient alveolar hypercapnia (HPC) was induced by administering CO2-enriched gas mixture (15% CO2, balance air) via the respirator inlet for 30 s, which rapidly lowered the arterial blood pH from a baseline of 7.40 ± 0.01 to 7.17 ± 0.02. Alveolar HPC markedly increased the responses of these C-fiber afferents to several chemical stimulants. For example, the C-fiber response to right atrial injection of the same dose of capsaicin (0.25–1.0 μg/kg) was significantly increased from 3.07 ± 0.70 impulses/s at control to 8.48 ± 1.52 impulses/s during HPC ( n = 27; P < 0.05), and this enhanced response returned to control within ∼10 min after termination of HPC. Similarly, alveolar HPC also induced significant increases in the C-fiber responses to right atrial injections of phenylbiguanide (4–8 μg/kg) and adenosine (0.2 mg/kg). In contrast, HPC did not change the response of pulmonary C fibers to lung inflation. Furthermore, the peak response of these C fibers to capsaicin during HPC was greatly attenuated when the HPC-induced acidosis was buffered by infusion of bicarbonate (1.36–1.82 mmol · kg−1 · min−1 for 35 s). In conclusion, alveolar HPC augments the responses of these afferents to various chemical stimulants, and this potentiating effect of CO2 is mediated through the action of hydrogen ions on the C-fiber sensory terminals.

The role of cesium‐ion bombardment in the formation of negative hydrogen ions on a converter surface

1987 ◽  
Vol 61 (11) ◽  
pp. 5000-5011 ◽  
Author(s):  
C. F. A. van Os ◽  
E. H. A. Granneman ◽  
P. W. van Amersfoort
Keyword(s):  
Ion Bombardment ◽  
Hydrogen Ions ◽  
Cesium Ion

The Role of Water Diffusion in the Corrosion of the French Nuclear Waste Glass SON 68 under Solution Saturation Conditions

2003 ◽  
Vol 807 ◽  
Author(s):  
Karine Ferrand ◽  
Abdesselam Abdelouas ◽  
Bernd Grambow ◽  
Jean-Louis Crovisier
Keyword(s):  
Inverse Correlation ◽  
Water Diffusion ◽  
Ionic Exchange ◽  
Hydrogen Ions ◽  
Static Tests ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Water Speciation ◽  
Good Agreement

ABSTRACTThe alteration kinetics of the French borosilicate glass SON 68 have been investigated in a dynamic system at 50°C and 90°C under solution saturation conditions. The pH was adjusted to 4.8, 7.2 and 9.8 with addition of chemical buffers or/and by bubbling CO2 in solution. In all experiments, Li and Cs leaching seems to be controlled by a diffusion process. The Li- and Cs-concentrations were used to calculate the sum of ionic exchange and matrix dissolution rates of the glass while Mo-concentrations indicate matrix dissolution. The final leaching rates in saturation condition of Mo were in the order of 10–4–10- g.m-2.d-1 in good agreement with those given in literature for static tests. The glass surface was studied by scanning and transmission electron microscopy (SEM, STEM) for analysis of the corrosion products and by infrared spectroscopy (FTIR) for water speciation and concentration. A good inverse correlation between the water content and the alkali concentrations released from the glass has been obtained. About three hydrogen ions replaced one alkali ion. Modeling of the experimental data using GM 2001 model gives water diffusion coefficients between 10–20 and 10–22 m2.s-1.

Proton semiconductors and energy transduction in biological systems

1978 ◽  
Vol 235 (3) ◽  
pp. R99-R114 ◽  
Author(s):  
H. J. Morowitz
Keyword(s):  
Proton Transport ◽  
Hydrogen Transfer ◽  
Atp Synthesis ◽  
Present Theory ◽  
Energy Transduction ◽  
Ion Concentration ◽  
Hydrogen Ions ◽  
Detailed Model ◽  
Hydrogen Ion Concentration

Energy transduction processes in biology are analyzed in terms of ordered chains of hydrogen bonds. The theory is an extension of studies on proton conductance in ice and is stimulated by current ideas on the role of hydrogen ions in oxidative phosphorylation and photophosphorylation. The possibility of a protochemistry paralleling electrochemistry is presented along with experimental evidence. The theory relating transmembrane electrochemical potential difference of hydrogen ion concentration to the synthesis of ATP is reviewed. The thermodynamics of hydrogen transfer across a membrane is treated including electrochemical and electromechanical factors. As a prelude to considering ATP synthesis, the acid-base dissociation reactions of ATP, ADP, and phosphate are analyzed. The thermodynamics of ATP synthesis is discussed and a detailed model is presented coupling the synthesis to proton transport. The model assumes a gated proton semiconductor that carries protons and allows them to interact specifically with well-defined substrate molecules. The physics of proton transport is outlined and various methods examined in the context of biological membranes. Emphasis is placed on solid-state proton semiconductors and the present theory of such structures is given. A section is included on possible biological applications of these semiconductors.

Role of Ions in Bias Enhanced Nucleation of Diamond

1995 ◽  
Vol 388 ◽  
Author(s):  
J.M. Lannon ◽  
J.S. Gold ◽  
Cd. Stinespring
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Surface Composition ◽  
Hydrogen Ions ◽  
Ion Energy ◽  
Transfer Processes ◽  
Ion Interactions ◽  
Ion Energies

AbstractIon-surface interactions are thought to play a role in bias enhanced nucleation of diamond. To explore this hypothesis and understand the mechanisms, surface studies of hydrogen and hydrocarbon ion interactions with silicon and silicon carbide have been performed. the experiments were carried out at room temperature and used in-situ auger analyses to monitor the surface composition of thin films produced or modified by the ions. Ion energies ranged from 10 to 2000 eV. Hydrogen ions were found to modify silicon carbide thin films by removing silicon and converting the resulting carbon-rich layers to a mixture of sp2- and sp3-C. the interaction of hydrocarbon ions with silicon was shown to produce a thin film containing SiC-, sp2-, and sp3-C species. IN general, the relative amount of each species formed was dependent upon ion energy, fluence, and mass. the results of these studies, interpreted in terms of chemical and energy transfer processes, provide key insights into the mechanisms of bias enhanced nucleation.

Modularity of osteoclast behaviour and “mode-specific” inhibition of osteoclast function

1990 ◽  
Vol 10 (6) ◽  
pp. 547-556 ◽  
Author(s):  
Mone Zaidi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bone Resorption ◽  
Specific Inhibition ◽  
Hydrogen Ions ◽  
Pharmacological Agents ◽  
Osteoclastic Activity ◽  
Osteoclast Function ◽  
Scanning Electron

This study is part of an attempt to understand the role of specific cellular activities in the bone resorptive process. Experiments were performed whereby known pharmacological agents were used to inhibit individual modes of osteoclastic activity, such as motility and secretion. The effects of such treatments on bone resorption were assessed by quantitative scanning electron microscopy. The compounds included colchicine, which was used to inhibit osteoclast motility; molybdate ions which were used to selectively inhibit the catalytic activity of secreted acid phosphatase, and omeprazole which was employed to inhibit the secretion of hydrogen ions. All compounds inhibited osteoclastic bone resorption, but singularly affected defined modes of activity. These findings suggest that each mode of osteoclastic activity is essential for the bone resorptive process, and that “mode-specific” inhibition may provide a means whereby excessive activity of the osteoclast can be regulated in disease.

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