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pH
pH
pH A value on a scale 0–14 which gives a measure of the acidity or alkalinity of a medium. A neutral medium has a pH of 7, acidic media have pH values of less than 7, and alkaline media of more than 7. The lower the pH the more acidic is the medium, the higher the pH, the more alkaline. The pH value is the logarithm of the reciprocal of the hydrogen ion concentration, expressed in moles per litre (pH = log
10l/H
+). Most pH values in natural systems lie in the range 4–9. Human blood has a pH of 7.4, ocean water 8.1–8.3, water in saline environments may have a pH around 9.0 or higher, and water in acidic soils may have a pH of 4.0 or less.
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Is pH paper an acceptable, low-cost alternative to the blood gas analyzer for determining pleural fluid pH?
Magazine article from: Chest; 11/1/1997; ; 700+ words
; The pH of malignant and parapneumonic effusions has...In a recent meta-analysis, pleural fluid pH had the highest diagnostic accuracy when compared...at our institution, we noticed that the pH of the pleural fluid was often inconsistent...
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Testing pH of Concrete
Magazine article from: Concrete International; 4/1/2007; ; 700+ words
; ...concrete typically begins its life at a highly basic pH of about 13, the pH values at exposed surfaces soon fall as reactions occur...carbonation. Over time, fronts of carbonated concrete, with pH values of about 8.5, advance below exposed surfaces...
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Effects of pH and Ph fluctuations on microbial fermentation and nutrient flow from a dual-flow continuous culture system
Magazine article from: Journal of Dairy Science; 3/1/2002; ; 700+ words
; ...used in two consecutive periods to study the effects of pH and pH fluctuations on microbial fermentation and nutrient flow...17.6% acid detergent fiber). Treatments were high pH (constant at 6.4); low pH (constant at 5.7); cycles...
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Inferring pH from conductivity and cation conductivity: two common methods are used, but errors can occur if the sample and the model do not match.
Magazine article from: Power Engineering; 11/1/2007; ; 700+ words
; Inferred pH is a method of continuously calculating pH from straight and cation conductivity. The method is not widely used in the United States, but is popular in Europe. Inferred pH is attractive because under certain conditions it can eliminate...
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pH testing: is it really necessary?
Magazine article from: Floor Covering Installer; 7/1/2006; ; 700+ words
; ...will want to read on. We will address several topics: 1. What is pH? 2. What is the difference between pH and a concentration of alkalinity? 3. How to properly test for pH. 4. How to tell if the tests are accurate. 5. What effect pH has...
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Extracellular pH regulates vascular endothelial growth factor activity.
Newspaper article from: Angiogenesis Weekly; 7/18/2003; 700+ words
; ...amp; NewsRx.net) -- Extracellular pH regulates vascular endothelial growth factor...to other extracellular parameters such as pH. Thus, the present study investigates the consequences of acidic pH on VEGF binding and activity in endothelial...
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pH-dependent conformational change of gastric mucin leads to sol-gel transition
Magazine article from: Biophysical Journal; 3/1/1999; ; 700+ words
; ...ability of gastric mucin to form a gel at low pH, which is crucial to the barrier function...measured diffusion coefficient with decreasing pH, suggesting an apparent increase in size...depolarized scattering ratio with decreasing pH, these results suggest that gastric mucin...
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Using pH & conductivity measurement for stock prep and wet end control: as paper mills have begun closing their water systems, the need for conductivity monitoring has increased. Careful sensor selection and placement are critical to accurate control.(Practical Solutions)
Magazine article from: Solutions - for People, Processes and Paper; 3/1/2002; ; 700+ words
; ...additives only work in a narrow range. Solution pH also affects the surface charge of the fiber...positively changed particles or chemicals. As the pH drops, this negative charge increases. In stock preparation, pH will generally not be constant throughout...
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Diurnal Variation in Ruminal pH on the Digestibility of Highly Digestible Perennial Ryegrass During Continuous Culture Fermentation
Magazine article from: Journal of Dairy Science; 6/1/2004; ; 700+ words
; ...pastures exhibit pronounced diurnal variation in ruminal pH, with pH being below values considered optimal for digestion. Using...system, the hypothesis that minimizing diurnal variation in pH would improve digestion of pasture when pH was low, but...
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Ruminal pH-DG link explored.(Bottom Line)
Magazine article from: Feedstuffs; 7/21/2008; ; 700+ words
; ...he discussed the important role ruminal pH may play in DG utilization, and, perhaps...presentations that discussed the ruminal pH-DG relationship. Some of the conclusions relative to ruminal pH from these poster sessions were as follows...
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pH
Book article from: World of Microbiology and Immunology
pH The term pH refers to the concentration of hydrogen ions (H+) in a solution. An acidic...whereas a basic environment is relatively depleted of hydrogen ions. The pH of biological systems is an important factor that determines which microorganism...
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Mutants: Enhanced Tolerance or Sensitivity to Temperature and pH Ranges
Book article from: World of Microbiology and Immunology
...tolerance or sensitivity to temperature and pH ranges Microorganisms have optimal environmental...while most organisms grow well in neutral pH conditions, some organisms grow well under...Fungi are able to sense extracellular pH and alter the expression of genes. Some...
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pH scale
Book article from: A Dictionary of Biology
pH scale A logarithmic scale for expressing the...a solution. To a first approximation, the pH of a solution can be defined as –...7 mol dm –3 , so the pH is 7. A pH below 7 indicates an acid solution...
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PH
Book article from: Fly Fishing: The Lifetime Sport
PH The pH scale is a measure of the acid and base concentration of a solution. A pH of 7 is neutral; 0-7 is the acid range and 7-14 is the base or alkalinity range. The presence of dissolved carbonates, bicarbonates, and hydroxides in water...
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ph
Book article from: A Dictionary of the Internet
ph Abbreviation for phonebook. phs are found in many educational establishment sites containing directories of staff. Such listings are similar to those associated with FINGER and have often been the target of ADDRESS HARVESTERS in search of email addresses that can be SPAM med.
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