scholarly journals Exposure of Agriculture Workers to Pesticides: The Effect of Heat on Protective Glove Performance and Skin Exposure to Dichlorvos

2019 ◽  
Vol 16 (23) ◽  
pp. 4798 ◽  
Author(s):  
Leigh Thredgold ◽  
Sharyn Gaskin ◽  
Chloe Quy ◽  
Dino Pisaniello
Keyword(s):  
Skin Penetration ◽  
Fold Increase ◽  
Organophosphate Insecticide ◽  
Temperature Dependent ◽  
Thermal Environments ◽  
Transdermal Penetration ◽  
Dermal Uptake ◽  
Chemical Permeation ◽  
Published Research ◽  
Kinetics Of

Dichlorvos is a toxic organophosphate insecticide that is used in agriculture and other insecticide applications. Dermal uptake is a known exposure route for dichlorvos and chemical protective gloves are commonly utilized. Chemical handling and application may occur in a variety of thermal environments, and the rates of both chemical permeation through gloves and transdermal penetration may vary significantly with temperature. There has been no published research on the temperature-dependent kinetics of these processes for dichlorvos and thus, this study reports on the effects of hot conditions for the concentrated and application strength chemical. Dichlorvos breakthrough times for non-disposable polyvinyl chloride (PVC) gloves at 60 °C were approximately halved compared to 25 °C for the concentrate (2 vs. 4 h) and more than halved at application strength (3 vs. >8 h). From permeation experiments covering 15–60 °C, there was a 460-fold increase in cumulative permeation over 8 h for the concentrated dichlorvos and the estimated activation energy halved. Elevated temperature was also shown to be a significant factor for human skin penetration increasing the cumulative penetration of concentrate dichlorvos from 179 ± 37 to 1315 ± 362 µg/cm2 (p = 0.0032) and application strength from 29.8 ± 5.7 to 115 ± 19 µg/cm2 (p = 0.0131). This work illustrates the important role temperature plays in glove performance and health risk via dermal exposure. As such, it is important to consider in-use conditions of temperature when implementing chemical hygiene programs.

Temperature Dependent Kinetics of the OH/HO2/O3Chain Reaction by Time-Resolved IR Laser Absorption Spectroscopy

2000 ◽  
Vol 104 (17) ◽  
pp. 3964-3973 ◽  
Author(s):  
Sergey A. Nizkorodov ◽  
Warren W. Harper ◽  
Bradley W. Blackmon ◽  
David J. Nesbitt
Keyword(s):  
Absorption Spectroscopy ◽  
Laser Absorption Spectroscopy ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Laser Absorption ◽  
Ir Laser ◽  
Kinetics Of

scholarly journals Biochar Chemistry in a Weathered Tropical Soil: Kinetics of Phosphorus Sorption

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 295
Author(s):  
Marina Moura Morales ◽  
Nicholas Brian Comerford ◽  
Maurel Behling ◽  
Daniel Carneiro de Abreu ◽  
Iraê Amaral Guerrini
Keyword(s):  
Mineral Soil ◽  
Soil Surface ◽  
Kinetic Studies ◽  
Inorganic Phosphorus ◽  
Initial Reaction ◽  
Phosphorus Sorption ◽  
P Sorption ◽  
Published Research ◽  
Kinetics Of

The phosphorus (P) chemistry of biochar (BC)-amended soils is poorly understood. This statement is based on the lack of published research attempting a comprehensive characterization of biochar’s influence on P sorption. Therefore, this study addressed the kinetic limitations of these processes. This was accomplished using a fast pyrolysis biochar made from a mix of waste materials applied to a highly weathered Latossolo Vermelho distrofico (Oxisol) from São Paulo, Brazil. Standard method (batch method) was used. The sorption kinetic studies indicated that P sorption in both cases, soil (S) and soil-biochar (SBC), had a relatively fast initial reaction between 0 to 5 min. This may have happened because adding biochar to the soil decreased P sorption capacity compared to the mineral soil alone. Presumably, this is a result of: (i) Inorganic phosphorus desorbed from biochar was resorbed onto the mineral soil; (ii) charcoal particles physically covered P sorption locations on soil; or (iii) the pH increased when BC was added SBC and the soil surface became more negatively charged, thus increasing anion repulsion and decreasing P sorption.

scholarly journals Kinetics of gluten protein-insolubilisation during pasta processing: Decoupling between time- and temperature-dependent effects

2019 ◽  
Vol 88 ◽  
pp. 103-109 ◽  
Author(s):  
Coline Martin ◽  
Marie-Hélène Morel ◽  
Adrien Reau ◽  
Bernard Cuq
Keyword(s):  
Gluten Protein ◽  
Temperature Dependent ◽  
Kinetics Of

An Alternative Approach to Analyzing the Interstitial Decay from the End of Range Damage During Millisecond Annealing

2008 ◽  
Vol 1070 ◽  
Author(s):  
Renata Camillo-Castillo ◽  
Mark E Law ◽  
Kevin S Jones
Keyword(s):  
Annealing Time ◽  
Dwell Time ◽  
Extended Defects ◽  
Temperature Dependent ◽  
Temperature Regimes ◽  
Alternative Approach ◽  
Small Times ◽  
Conventional Annealing ◽  
Kinetics Of ◽  
Anneal Temperature

ABSTRACTFlash-assist Rapid Thermal Processing (RTP) presents an opportunity to investigate annealing time and temperature regimes which were previously not accessible with conventional annealing techniques such as Rapid Thermal Annealing. This provides a unique opportunity to explore the early stages of the End of Range (EOR) damage evolution and also to examine how the damage evolves during the high temperature portion of the temperature profile. However, the nature of the Flash-assist RTP makes it is extremely difficult to reasonably compare it to alternative annealing techniques, largely because the annealing time at a given temperature is dictated by the FWHM of the radiation pulse. The FWHM for current flash tools vary between 0.85 and 1.38 milliseconds, which is three orders of magnitude smaller to that required for a RTA to achieve similar temperatures. Traditionally, the kinetics of the extended defects has been studied by time dependent studies utilizing isothermal anneals; in which specific defect structures could be isolated. The characteristics of Flash-assist RTP do not allow for such investigations in which the EOR defect evolution could be closely tracked with time. Since the annealing time at the target temperature for the Flash-assist RTP is essentially fixed to very small times on the order of milliseconds, isochronal anneals are a logical experimental approach to temperature dependent studies. This fact presents a challenge in the data analysis and comparison. Another feature of Flash-assist RTP which makes the analysis complex is the ramp time relative to the dwell time spent at the peak fRTP temperature. As the flash anneal temperature is increased the total ramp time can exceed the dwell time at the peak temperature, which may play a significantly larger role in dictating the final material properties. The inherent characteristics of Flash-assist RTP have consequently required the development of another approach to analyzing the attainable experimental data, such that a meaningful comparison could be made to past studies. The adopted analysis entails the selection of a reference anneal, from which the decay in the trapped interstitial density can be tracked with the flash anneal temperature, allowing for the kinetics of the interstitial decay to be extracted.

scholarly journals Temperature Dependent Seed Germination of Dalbergia nigra Allem (Leguminosae)

2001 ◽  
Vol 44 (4) ◽  
pp. 401-404 ◽  
Author(s):  
Fernanda G. A. Ferraz-Grande ◽  
Massanori Takaki
Keyword(s):  
Seed Germination ◽  
Endangered Species ◽  
High Temperatures ◽  
Broad Temperature Range ◽  
Optimum Temperature ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dalbergia Nigra ◽  
The Mean ◽  
Kinetics Of

The germination of endangered species Dalbergia nigra was studied and 30.5° C was found as optimum temperature, although the species presented a broad temperature range where germination occurs and light had no effect. The analysis of kinetics of seed germination confirmed the asynchronized germination below and above the optimum temperature. The light insensitive seed and germination also at high temperatures indicated that D. nigra could occur both in understories and gaps where the mean temperature was high.

Changes in lipophosphoglycan and gene expression associated with the development ofLeishmania majorinPhlebotomus papatasi

Parasitology ◽  
1995 ◽  
Vol 111 (3) ◽  
pp. 275-287 ◽  
Author(s):  
E. M. B. Saraiva ◽  
P. F. P. Pimenta ◽  
T. N. Brodin ◽  
E. Rowton ◽  
G. B. Modi ◽  
...  
Keyword(s):  
Differential Expression ◽  
Fold Increase ◽  
Surface Expression ◽  
Side Chain ◽  
Surface Coat ◽  
Natural Vector ◽  
Metacyclic Promastigotes ◽  
Kinetics Of

SUMMARYStage-specific molecular and morphogenic markers were used to follow the kinetics of appearance, number, and position of metacyclic promastigotes developing during the course ofL. majorinfection in a natural vector,Phlebotomus papatasi. Expression of surface lipophosphoglycan (LPG) on transformed promastigotes was delayed until the appearance of nectomonad forms on day 3, and continued to be abundantly expressed by all promastigotes thereafter. An epitope associate with arabinose substitution of LPG side-chain oligosaccharides, identified by its differential expression by metacyclics invitro, was detected on the surface of a low proportion of midgut promastigotes beginning on day 5, and on up to 60% of promatigotes on days 10 and 15. In contrast 100% of the parasites egested from the mouthparts during forced feeding of 15 day infected flies stained strongly for this epitope. At each time-point, the surface expression of the modified LPG was restricted to morphologically distinguished metacyclic forms. Ultrastructural study of the metacyclic surface revealed an approximate 2-fold increase in the thickness of the surface coat compared to nectomonad forms, suggesting elongation of LPG as occurs during metacyclogenesisin vitro. A metacyclic-associated transcript (MAT-1), another marker identified by its differential expression invitro, also showed selective expression by promastigotes in the fly, and was used inin situhybridization studies to demonstrate the positioning of metacyclics in the anterior gut.

Transformation of Rana tigrina during Progressive Metamorphosis

2021 ◽  
Vol 30 (1) ◽  
pp. 102-109
Author(s):  
Dhananjay Mishra ◽  
K.Venu Achari
Keyword(s):  
Acid Phosphatase ◽  
Total Protein ◽  
Ribonucleic Acid ◽  
Fold Increase ◽  
Total Activity ◽  
Total Protein Content ◽  
Total Carbohydrate ◽  
Rna Content ◽  
Rana Tigrina ◽  
Kinetics Of

We determined the kinetics of metamorphosis, apoptosis, and tail regression in Rana tigrina. Acid phosphatase activity (µMole Pi.hr-1.tail-1) in the growing and regressing tail attended six to thirty fold increase respectively. However total activity in the trunk was decreased through progressive growing stages of metamorphosis. Total protein content in the trunk of tadpoles at climax stage (XXI) was decrease (35%) from 2.6mg/ml to 1.7mg/ml. The tail of tadpole tissue has shown a two fold increase in total Ribonucleic Acid (RNA) content from stage III to stage XVIII. But there was again decrease in total RNA content at climax stage (stage XXI). This might be possible due to decreased protein synthetic status. When the experiment was performed in trunk homogenate the amount of total carbohydrate (mg/ml) was slightly increased from 37mg/ml to 38.6mg/ml. this might be due to increase in the activity of α-amylase enzymes in the viscera of developing tadpole when it reached the climax stage.

Platelet adhesion by Subendothelium-Bound Factor VIII-VWF:Kinetics and Molecular Weight Dependence

1979 ◽  
Author(s):  
P. A. Bolhuis ◽  
K. S. Sakariassen ◽  
J. J. Sixma
Keyword(s):  
Molecular Weight ◽  
Platelet Adhesion ◽  
Fold Increase ◽  
Surface Concentration ◽  
Albumin Solution ◽  
Molecular Weight Dependence ◽  
High Molecular Weight Component ◽  
Von Willebrand ◽  
Kinetics Of

Platelet adhesion to human subendothelium was determined by perfusions with albumin solutions containing 51Cr-labeled, aspirin-treated platelets and washed red cells (hematocrit 40%) at 37° and a flow rate of 135 ml/min. Adherence was similar with Von Willebrand plasma instead of albumin solution and addition of purified FVIII-VWF caused adhesion similar to that from normal plasma. Incubation of subendotheliurn with FVIII-VWF resulted of binding of FVIII-VWF at the surface and in subsequent perfusions a surface concentration of, FVII-VWF/cm2 was shown to correct the platelet adhesion in albumin solutions towards normal. The kinetics of binding of FVIII-VWF and platelets to the subendothelium confirm the role of bound FVIII-VWF in adhesion. Binding of FVII-VWF occurs rapidly in the first minute of perfusion to about 4 x 10-4U/cm2 and then increases further to about 10-3 u/cm2 in 5 min. Platelet adhesion is similar for perfusates with and without FVIII-WF in the first minute; then the presence of FVIII-VWF results in a two-fold increase of adhesion at 5 min. Reduced adhesion was found with the high-molecular weight component of FVIII-VWF obtained by high iconic strength dissociation. Also, the activity of glycin precipitated FVIII-VWF (e.g. Hemofil FVIII-concentrate) is impaired, cross-electrophoresis of FVIII-VWF from cryoprecipitate and FVIII-VWF after glycin precipitation showed an increased mobility or the latter, indicating a reduced molecular siie. From these experiments we conclude tnat platelet adhesion is mediated by subendothelium-bound FVIII-WWF. The degree of adhesion may depend on the molecular weight of the FVIII-VWF.

Sign in / Sign up

Export Citation Format

Share Document