scholarly journals ADSORPTION OF BACTERIOPHAGE UNDER VARIOUS PHYSIOLOGICAL CONDITIONS OF THE HOST

1940 ◽  
Vol 23 (5) ◽  
pp. 631-642 ◽  
Author(s):  
M. Delbrück
Keyword(s):  
Rate Constant ◽  
Physiological State ◽  
Adsorption Rate ◽  
Bacterial Host ◽  
Physiological Conditions ◽  
Adsorption Rate Constant ◽  
Assay Methods ◽  
Free Phage

1. The adsorption rate constant of phage to bacterium is found to change between wide limits, depending on the physiological state of the bacterium. 2. The experiments of Krueger and of Schlesinger on the residual free phage in contact with an excess of bacteria are discussed and the view of Schlesinger, that they represent phage particles with reduced affinity to the bacterial host is supported by experiments. 3. The theory of von Smoluchowski and Schlesinger is compared with the experiments. 4. The implications of these findings for the assay methods currently used are discussed.

scholarly journals EFFECT OF DIATOMEAOUS EARTH TREATMENT USING HYDROGEN CHLORIDE AND SULFURIC ACID ON KINETICS OF CADMIUM(II) ADSORPTION

2010 ◽  
Vol 2 (2) ◽  
pp. 107-112
Author(s):  
Nuryono Nuryono ◽  
Narsito Narsito
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Hydrogen Chloride ◽  
Rate Constant ◽  
Diatomaceous Earth ◽  
Adsorption Rate ◽  
Physical Interaction ◽  
First Order ◽  
Adsorption Rate Constant ◽  
Kinetics Of

In this research, treatment of diatomaceous earth, Sangiran, Central Java using hydrogen chloride (HCl) and sulfuric acid (H2SO4) on kinetics of Cd(II) adsorption in aqueous solution has been carried out. The work was conducted by mixing an amount of grounded diatomaceous earth (200 mesh in size) with HCl or H2SO4 solution in various concentrations for two hours at temperature range of 100 - 150oC. The mixture was then filtered and washed with water until the filtrate pH is approximately 7 and then the residue was dried for four hours at a temperature of 70oC. The product was used as an adsorbent to adsorb Cd(II) in aqueous solution with various concentrations. The Cd(II) adsorbed was determined by analyzing the rest of Cd(II) in the solution using atomic absorption spectrophotometry. The effect of treatment was evaluated from kinetic parameter of adsorption rate constant calculated based on the simple kinetic model. Results showed  that before equilibrium condition reached, adsorpstion of Cd(II) occurred through two steps, i.e. a step tends to follow a reaction of irreversible first order  (step I) followed by reaction of reversible first order (step II). Treatment with acids, either hydrogen chloride or sulfuric acid, decreased adsorption rate constant for the step I from 15.2/min to a range of 6.4 - 9.4/min.  However, increasing concentration of acid (in a range of concentration investigated) did not give significant and constant change of adsorption rate constant. For step II process,  adsorption involved physical interaction with the sufficient low adsorption energy (in a range of 311.3 - 1001 J/mol).     Keywords: adsorption, cdmium, diatomaceous earth, kinetics.

Kinetics and Adsorption Ions of Heavy Metal by Modified Alumino-Silicates

2021 ◽  
Vol 316 ◽  
pp. 170-174
Author(s):  
Elena G. Filatova ◽  
Yury N. Pozhidaev
Keyword(s):  
Heavy Metal ◽  
Rate Constant ◽  
Heavy Metal Ions ◽  
Second Order ◽  
Adsorption Rate ◽  
Order Model ◽  
Adsorption Rate Constant ◽  
Maximum Value ◽  
Pseudo Second Order ◽  
Kinetics Of

Adsorption isotherms of Ni (II) and Cu (II) ions by alumino-silicates, modified with N, N'-bis (3-triethoxysilylpropyl) thiocarbamide (BTM-3), and HCl, were obtained. The adsorption kinetics of heavy metal ions is studied, using the kinetic pseudo-first and pseudo-second order models. It is shown that, when alumino-silicates are modified, the rate and energy of adsorption increase. It is established that the kinetics of the adsorption of the studied ions is best described by a pseudo-second order model. The maximum value of the adsorption rate constant of 33.7∙10-5 g/ (mmol min) corresponds to nickel (II) ions for alumino-silicates, modified with HCl. The maximum value of the adsorption rate constant value of 2.91∙10-5 g/ (mmol min) for alumino-silicates, modified with BTM-3, corresponds to Cu (II) ions.

A Study on Surfactant Adsorption Kinetics:  Effect of Bulk Concentration on the Limiting Adsorption Rate Constant

Langmuir ◽  
2000 ◽  
Vol 16 (10) ◽  
pp. 4573-4580 ◽  
Author(s):  
Chengdi Dong ◽  
Ching-Tien Hsu ◽  
Chin-Yuan Chiu ◽  
Shi-Yow Lin
Keyword(s):  
Rate Constant ◽  
Adsorption Kinetics ◽  
Adsorption Rate ◽  
Surfactant Adsorption ◽  
Bulk Concentration ◽  
Adsorption Rate Constant

scholarly journals A Simple Method for Calculating the Overall Adsorption Rate Constant in the Wheeler–Jonas Equation

2011 ◽  
Vol 29 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Chongyang Zhou ◽  
Shujuan Feng ◽  
Gouqing Zhou ◽  
Yuren Jin ◽  
Junfu Liang ◽  
...  
Keyword(s):  
Rate Constant ◽  
Adsorption Rate ◽  
Simple Method ◽  
Adsorption Rate Constant

scholarly journals KINETIC STUDY ON ADSORPTION OF CHROMIUM(lIl) TO DIATOMACEOUS EARTH PRE-TREATED WITH SULFURIC AND HYDROCHLORIC ACIDS

2010 ◽  
Vol 3 (1) ◽  
pp. 32-38
Author(s):  
Nuryono Nuryono ◽  
V.V.H. Susanti ◽  
Narsito Narsito
Keyword(s):  
Rate Constant ◽  
Adsorption Kinetics ◽  
Diatomaceous Earth ◽  
Atomic Absorption Spectrophotometry ◽  
Adsorption Rate ◽  
Physical Interaction ◽  
Kinetics Of Adsorption ◽  
Pre Treatment ◽  
Sulfuric And Hydrochloric Acids ◽  
Kinetics Of

In this research, the effect of Sangiran diatomaceous earth pre-treatment with sulfuric acid (H2SO4) and hydrochloric acid (HCl) on the kinetics of adsorption for Cr(III) in aqueous solution has been studied. The research has been carried out by mixing an amount of diatomeaeous earth with HCl or H2SO4 in various concentrations for two hours at temperature of 150 - 200°C. The mixture was washed with water until neutral, and the residue was dried at 70°C for four hours. The result then was used as adsorbent. Adsorption was carried out by mixing an amount of adsorbent with Cr(III) solution in various contact times. Ion adsorbed was determined by analyzing filtrate using atomic absorption spectrophotometry. The effect of pre-treatment on adsorption kinetics was evaluated based on kinetic parameters, i.e. constant of adsorption rate by using Langmuir-Hinshelwood kinetics and using two-process kinetics (fast and slow processes). Adsorption kinetics calculated using LH equation gave negative value for adsorption rate constant of zero order (k0). On the other words, the LH kinetics might not be applied for adsorption of Cr(III) to diatomaceous earth adsorbent. Results of kinetics study approached using two processes (fast and slow) showed that adsorption of Cr(III) occurred in two processes with rate constant of fast adsorption, kc, 0.041/min, rate constant of slow adsorption, kl, 0.0089/min, and of slow desorption, k'l, 0.089/menit. Pre-treatment with HCl up to 10 M decreased either kc, kl or k'l, while pre-treatment with H2SO4 1M increased kc to 0.061/min, decreased kl to 0.00424 and k'l to 0.0139/min. On pre-treatment with H2SO4 higher than 6 M significantly decreased three constants above. Based on the Gibbs energy change (4.31 - 6.79 kJ/mole) showed that adsorption involved physical interaction.   Keywords: adsorption, chromium, diatomaceous earth, kinetics, Langmuir-Hinshelwood

scholarly journals Effect of Vascular Activity in the Determination of Rate Constants for the Uptake of 18F-Labeled 2-Fluoro-2-Deoxy-D-Glucose: Error Analysis and Normal Values in Older Subjects

1986 ◽  
Vol 6 (6) ◽  
pp. 724-738 ◽  
Author(s):  
A. C. Evans ◽  
M. Diksic ◽  
Y. L. Yamamoto ◽  
A. Kato ◽  
A. Dagher ◽  
...  
Keyword(s):  
Rate Constant ◽  
Gray Matter ◽  
Rate Constants ◽  
Cerebral Blood Volume ◽  
Physiological State ◽  
Control Group ◽  
Vascular Activity ◽  
Regional Cerebral Blood Volume ◽  
Wide Range

Regional cerebral blood volume (CBV) can be calculated using data obtained during the kinetic analysis of 18F-labeled 2-fluoro-2-deoxy-d-glucose (FDG) uptake measured by positron emission tomography (PET). As a result the influence of vascular activity upon the determination of FDG rate constants can be minimized. The method is investigated by simulation experiments and by analysis of PET studies on seven older, healthy human volunteers aged 52–70 years. The accuracy of measured FDG rate constants k1, k2, and k3, obtained either by omitting the early portion of the uptake curve or by explicit inclusion of CBV as a fit parameter, is compared. The root mean square error in measured rate constant for the latter method is equivalent to that obtained by omitting the first 2.5–3 min of tissue data and neglecting the CBV term. Hence, added information about the physiological state of the tissue is obtained without compromising the accuracy of the (FDG) rate constant measurement. In hyperemic tissue the explicit determination of the vascular fraction results in more accurate estimates of the FDG rate constants. The ratio of CBV determined by this method to CBV obtained using C15O in six subjects with CBV in the normal range was 0.92 ± 0.32. A comparison of the CBV image obtained by this method with that obtained using C15O in an arteriovenous malformation case demonstrates the accuracy of the approach over a wide range of CBV values. The mean value for CBV fraction in gray matter obtained by this method in the older control group was 0.040 ± 0.014. Average gray matter rate constants obtained were k1 = 0.084 ± 0.012, k2 = 0.150 ± 0.071, and k3 = 0.099 ± 0.045 min−1.

Ascorbic Acid Catalyzes Nitric Oxide Production from Nitrite Ions.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1574-1574 ◽  
Author(s):  
Nathawut Sibmooh ◽  
Barbora Piknova ◽  
Alan N. Schechter
Keyword(s):  
Nitric Oxide ◽  
Ascorbic Acid ◽  
Rate Constant ◽  
Dehydroascorbic Acid ◽  
Nitrite Reduction ◽  
Erythrocyte Membranes ◽  
No Production ◽  
Ferrous Ions ◽  
Physiological Conditions ◽  
Ferrous Heme

Abstract We have previously shown that nitrite ions can be reduced by hemoglobin to nitric oxide (NO), a ubiquitous signaling molecule and potent vasodilator. Nitrite serves as a stable tissue and vascular source for NO production; the reduction reaction is maximal at about 50% oxygen saturation values and is enhanced at low pH but little is known about other effectors of this reaction. In the current work, we studied the effect of ascorbic acid on nitrite reduction under physiological conditions using chemiluminescence to quantify NO production. In physiological buffer, this reaction has a rate constant of about 1×10−5 M−1.s−1. Thus, a significant production of NO would likely occur in plasma only at pharmacological levels of ascorbic acid (> 1 mM) although lowering pH below 7.0 markedly enhances this reaction. Loading human erythrocytes with 0.5 mM dehydroascorbic acid, which is in redox equilibrium with ascorbic acid and which can significantly raise intracellular ascorbic acid levels, increased basal levels of nitrite ions from 42±9.0 nM to 98±56 nM. Uptake of nitrite ions into erythrocytes by incubation in 10 μM nitrite was increased about 1.5 fold by dehydroascorbic acid and the half-time of nitrite loss was slowed to the same extent. Ascorbic acid also reduced free ferric heme in erythrocytes and plasma to ferrous heme which catalyzed the reduction of nitrite to NO with a rate constant of 2.3×103 M−1.s−1 under physiological conditions. However, free ferrous ions did not significantly produce NO in physiological buffer (rate constant = 1.8×10−2 M−1.s−1). The reaction of ferrous heme with nitrite was not affected by heme binding to proteins such as hemopexin and albumin, or erythrocyte membranes. These results suggest that physiological levels of ascorbic acid (20–80 μM in plasma and erythrocytes) may act to catalyze NO production in the blood by promoting the reduction of nitrite ions by free ferrous heme and by increasing intra-erythrocytic levels of nitrite ions which can be reduced to NO by deoxyhemoglobin.

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