scholarly journals Effect of rate of application on degradation of imazethapyr in groundnut and soil under tropical Indian condition

2015 ◽  
Vol 7 (2) ◽  
pp. 714-718 ◽  
Author(s):  
C. Babu ◽  
P. Janaki ◽  
C. Chinnusamy
Keyword(s):  
Groundwater Contamination ◽  
Weed Control ◽  
Half Life ◽  
Order Reaction ◽  
Tropical Condition ◽  
First Order ◽  
Inappropriate Use ◽  
Time Of Harvest ◽  
Different Doses ◽  
Surface And Groundwater

Pesticides though formulated to be biologically degradable, few herbicides reported to cause surface and groundwater contamination which needs the monitoring of herbicide residues in environment continuously. Thus, to monitor the persistence and residues in crops, imazethapyr degradation studies were conducted in soil with groundnut cropping under Indian tropical condition. A groundnut field was treated with different doses of imazethapyr as early post emergence. Results showed that the degradation of imazethapyr in soil and groundnut plant followed first order reaction kinetics irrespective of the dose. The residue of imazethapyr persists in soil up to 60 days at higher rates of application while it persists up to 30 days in plant with the calculated half life of 2.8 to 7.4 days in soil and 5.1 to 5.9 days in plant. At the time of harvest, the residue of imazethapyr in soil, groundnut haulm or pods were below the detectable limit of 0.008 mg/kg across different doses of application. However, the continuous and inappropriate use in light textured soils may cause groundwater contamination and bioaccumulation in plant system. Hence, a pre harvest interval of 75 days must be allowed after the application of imazethapyr for the weed control in groundnut.

A Human Pharmacological Study Comparing Conventional Heparin and a Low Molecular Weight Heparin Fragment

1985 ◽  
Vol 53 (02) ◽  
pp. 208-211 ◽  
Author(s):  
G Bratt ◽  
E Törnebohm ◽  
D Lockner ◽  
G Bergströ
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Low Molecular Weight Heparin ◽  
Pharmacological Study ◽  
Low Molecular Weight ◽  
Dose Dependency ◽  
First Order ◽  
First Order Kinetics ◽  
Heparin Activity ◽  
Different Doses

SummaryThe pharmacokinetics of a heparin fragment of low molecular weight (LMWH) of 4000-5000 D and unfractioned standard heparin (UFH) have been studied after i. v. injections of different doses and infusions in 8 humans.The heparin activity was significantly higher and the effect on APTT lower after LMWH fragment as compared to UFH in the same doses.The half-life of heparin activity was about 1 hr for UFH and about 2 hr for LMWH. LMWH was found to be eliminated according to first order kinetics and there were no signs of dose dependency.

Sulphur metabolism in sheep. II. The absorption of inorganic sulphate and inorganic sulphide from the sheep's rumen

1969 ◽  
Vol 20 (4) ◽  
pp. 739 ◽  
Author(s):  
AC Bray
Keyword(s):  
Half Life ◽  
Order Reaction ◽  
First Order Reaction ◽  
Direct Absorption ◽  
Sulphur Metabolism ◽  
Buffer Solution ◽  
Solution Ph ◽  
First Order ◽  
Sulphide Concentration ◽  
Inorganic Sulphate

The absorption of inorganic [35S]sulphate and inorganic [35S]sulphide from the reticulorumen was studied by measuring the decrease of radioactivity and decrease in sulphide concentration in the rumen and by the increase in radioactivity in the bloodstream. Normal rumen contents were replaced with buffer solution (pH 6.6). The pattern of sulphide disappearance from the rumen followed that of a first order reaction and was extremely rapid. The estimated half-life of rumen sulphide ranged from 10 to 22 min. Direct absorption from the rumen appeared to be the main mechanism involved in the sulphide loss. Under similar conditions little sulphate was lost from the rumen and absorption of sulphate across the rumen wall appeared to be negligible.

Performance and Persistence of Atrazine

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 413-416 ◽  
Author(s):  
G. A. Buchanan ◽  
A. E. Hiltbold
Keyword(s):  
Half Life ◽  
Field Experiments ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Time Of Application ◽  
Made In

Field experiments were conducted from 1967 to 1971 to determine the influence of incorporation and time of application on the performance and persistence of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine]. Both grass and broadleaf weeds were effectively controlled by atrazine on all dates of application. Both the 2.8 and 5.6 kg/ha rates were effective as preplant incorporated or preemergence treatments. Persistence of atrazine did not differ with respect to method of application. Applications of atrazine made in April and May were degraded more rapidly than were applications made in February and March. Loss curves generally corresponded to a first-order reaction with atrazine showing an average half-life of 20 days from February to July.

scholarly journals Influence of arbuscular mycorrhizal fungi on glyphosate dissipation rate in okra cultivated sodic soil of Tamil Nadu

2020 ◽  
Vol 41 (6) ◽  
pp. 1542-1549
Author(s):  
P.M. Brindhavani ◽  
◽  
P. Janaki ◽  
G. Gomadhi ◽  
T. Ramesh ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Half Life ◽  
Tamil Nadu ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Order Reaction ◽  
Sodic Soil ◽  
First Order ◽  
The Mean

Aim: To elucidate the influence of non target Arbuscular Mycorrhizal (AM) fungi on glyphosate dissipation in okra cultivated sodic soil of Tamil Nadu. Methodology: A field experiment was carried out during Rabi 2017-18 to study the interactive effect of glyphosate and Arbuscular mycorrhizal fungi (AM) on glyphosate dissipation in sodic soil from okra (A. esculentus) grown field. Experiment was laid adopting Randomized Block Design (RBD) with different rates of glyphosate and with and without AM fungi. Glyphosate was applied as pre-plant herbicide 20 days before sowing, and AM biofertilizer was applied as basal before sowing of okra. Soil samples were collected from the field at different time interval after glyphosate application and analysed for glyphosate and Amino Methyl Phosphonic Acid (AMPA) residues. Results: Glyphosate persistence decreased with time and degraded with the mean half-life ranging from 5.09 to 10.35 days by following first order reaction kinetics. AMPA was witnessed from day 1 and increased up to 15th day and followed first order reaction kinetics dissipation with the mean half-life of 8.62 to 13.06 days. Glyphosate and AMPA residues were recorded below detection limit (0.01 mg kg-1) on 45th and 60th days, respectively, in soil. Interpretation: The higher rates of glyphosate showed enhanced persistence of glyphosate and its metabolite AMPA in soil, hence application of AM fungi 100 kg ha-1 with lower glyphosate rate of 6 ml/L can be recommended for okra cultivated sodic soil with the safer waiting period of after 45 days harvest.

Biotic and Abiotic Factors in Fumonisin Bi Production and Stability

1994 ◽  
Vol 77 (2) ◽  
pp. 517-521 ◽  
Author(s):  
Joseph Le Bars ◽  
Pierrette Le Bars ◽  
Jacques Dupuy ◽  
Hamid Boudra ◽  
Renee Cassini
Keyword(s):  
Thermal Decomposition ◽  
Half Life ◽  
Fusarium Moniliforme ◽  
Initial Rate ◽  
Abiotic Factors ◽  
Fumonisin B1 ◽  
Order Reaction ◽  
First Order ◽  
Biotic And Abiotic Factors ◽  
Moisture Contents

Abstract The occurrence of a few cases of equine leuko-encephalomalacia in France has indicated a potentially widespread, low-level contamination of corn by fumonisins. To develop strategies for prevention, biotic and abiotic factors in fumonisin B1 (FB1) production and stability were investigated. The potential for FB1 production from 2 groups of Fusarium moniliforme strains was tested in corn cultures. The first group consisted of 48 strains that were previously isolated from corn, asparagus, watermelon, and vanilla. The second group consisted of 25 strains that were freshly isolated from corn. Respective frequencies in the first and second groups of strains and in each toxigenic class were as follows: 23 and 0%, <50 μg/g; 16 and 12%, 50–200 μg/g; 23 and 4%, 200–800 μg/g; 33 and 68%, 800–3200 μg/g; and 5 and 16%, >3200 μg/g. The initial rate of FB1 production decreased in the following order of temperature: 20, 25, 15, 30, 10°C. FB1 was not detected at 5, 35, or 40ΰC. Also, no FB1 was detected in confined atmosphere at 25°C during 10 weeks. Significant amounts (>200 μg/g) of FB1 were produced within 12 days, in laboratory conditions, with moisture contents of corn frequently encountered at harvest (≥27%). Thermal decomposition of FB1 in dried corn culture followed a first-order reaction. Half-life times at 150, 125, and 100°C were 10, 38, and 175 min, respectively. Therefore, contamination of foods and feeds by this stable mycotoxin is, theoretically, a permanent threat.

Clearance and In Vivo Release by Heparin of Human Platelet Factor 4 (PF4) in the Rabbit

1984 ◽  
Vol 52 (02) ◽  
pp. 157-159 ◽  
Author(s):  
M Prosdocimi ◽  
N Scattolo ◽  
A Zatta ◽  
F Fabris ◽  
F Stevanato ◽  
...  
Keyword(s):  
Half Life ◽  
Human Platelet ◽  
Slow Component ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
In Vivo Release ◽  
Partial Release ◽  
Different Doses ◽  
New Zealand Rabbits

Summary13 male New Zealand rabbits were injected with two different doses (25 μg/Kg and 100 μg/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 ± 0.16 and 1.76 ± 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min.The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 ± 5.9 min and 30.9 ± 2.19 min respectively.

Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

2014 ◽  
Vol 28 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Lech W. Szajdak ◽  
Jerzy Lipiec ◽  
Anna Siczek ◽  
Artur Nosalewicz ◽  
Urszula Majewska
Keyword(s):  
Reaction Rate ◽  
Inorganic Compounds ◽  
Model Performance ◽  
Order Reaction ◽  
First Order Reaction ◽  
Order Kinetic ◽  
Time Data ◽  
First Order ◽  
Concentration Changes ◽  
Reaction Constants

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

1993 ◽  
Vol 28 (2) ◽  
pp. 135-144 ◽  
Author(s):  
S. Matsui ◽  
R. Ikemoto Yamamoto ◽  
Y. Tsuchiya ◽  
B. Inanc
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Kinetic Equations ◽  
Fluidized Bed Reactor ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Glucose Decomposition ◽  
Reaction Equations ◽  
Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

In-vitro Kinetic Hydrolysis Study of Metronidazole Derivatives with Carvacrol and Eugenol Using Validated RP-HPLC Method

2020 ◽  
Vol 16 ◽  
Author(s):  
M. Alarjah
Keyword(s):  
Half Life ◽  
Hplc Method ◽  
Hydrolysis Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Rp Hplc ◽  
Pharmacokinetic Properties ◽  
Pseudo First Order ◽  
Kinetic Hydrolysis

Background: Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole. Objective: In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method. Method: Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC. Results: The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH, while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively. Conclusion: The developed method was accurate, sensitive, and selective for the prodrugs. For most of the prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo study for the metronidazole derivatives with monoterpenes and eugenol.

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