scholarly journals Study on the Degradation Effect of Plant-Derived Active Ingredients on Organophosphorus Pesticides

2020 ◽  
Vol 1 (1) ◽  
pp. 6
Author(s):  
Jun Sun ◽  
Tongxin Zhang
Keyword(s):  
Measurement Method ◽  
Detection Method ◽  
Organic Phosphorus ◽  
Organophosphorus Pesticides ◽  
Quantitative Detection ◽  
Active Ingredients ◽  
Degradation Rates ◽  
Before And After ◽  
Concentration Changes ◽  
Degradation Effect

In order to explore new ways and methods for the degradation of organophosphorus pesticides, the degradation effects of plant-derived active ingredients on three organophosphorus pesticides were studied. Mix Rhubarb, Pittosporum bark, Hibiscus bark, and Chinese gall in 9:4:3:2 parts by mass, crush and soak in water, use GC-MS quantitative detection method, rapid pesticide residue measurement method, and compare the organic phosphorus before and after the test Pesticide concentration changes, clarify its degradation effect on organophosphorus pesticides. The results showed that the degradation rates of chlorpyrifos and parathion were 93.2% and 92.9% in the extract within 2 minutes; the degradation rate of dichlorvos in the extract within 17 hours was 66.67%, and the degradation of chlorpyrifos within 11 hours the rate is 48.69%. This study shows that the extracts of rhubarb, sea tongs bark, hibiscus bark, and gallnut have significant degradation effects on chlorpyrifos, parathion, dichlorvos and other organophosphorus pesticides.

scholarly journals A Repeatable and Reproducible Digital Method to Quantify the Cement Excess and Enamel Loss after Debonding Lingual Multibracket Appliance Therapy

2021 ◽  
Vol 11 (3) ◽  
pp. 1295
Author(s):  
Alba Belanche Monterde ◽  
Alberto Albaladejo Martínez ◽  
Alfonso Alvarado Lorenzo ◽  
Adrián Curto ◽  
Jorge Alonso Pérez-Barquero ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Measurement Method ◽  
Dental Arch ◽  
Micro Computed Tomography ◽  
Morphometric Measurement ◽  
Before And After ◽  
Repeatability And Reproducibility ◽  
Lingual Brackets ◽  
Multibracket Appliance ◽  
Area And Volume

The aim of the present study is to present a repeatable, reproductible, and accurate morphometric measurement method for measuring and quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances. Ten conventional lingual brackets were cemented in 10 extracted teeth embedded into an epoxy resin model simulating a dental arch. This model was scanned before and after bonding the lingual brackets, after debonding, and after polishing the surfaces. We also performed a Micro-Computed Tomography scan of the lingual brackets used. Afterward, the standard tessellation language (STL) digital file was aligned, each tooth was segmented individually, and the file was re-aligned using engineer morphometry software. Inter-operator and intra-operator comparative analyses were performed using the ANOVA test, and the repeatability and reproducibility of the morphometric measurement technique were analyzed using Gage R&R statistical analysis. Repeatability showed 0.07% and 0.16% variability associated with the area and volume measures, respectively, while reproducibility showed 0.00% variability associated with the area and volume measures, respectively. In conclusion, the morphometric measurement technique is a repeatable, reproductible, and accurate morphometric measurement method for quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances.

scholarly journals REACTIVITY OF NUCLEOPHILES AND α-EFFECT IN SUBSTITUTION PROCESSES AT ELECTRON - DEFICIENCY CENTERS

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Anatolii Popov ◽  
Illia Kapitanov ◽  
Anna Serdyuk ◽  
Aleksandr Sumeiko
Keyword(s):  
Organic Phosphorus ◽  
Organophosphorus Pesticides ◽  
Reaction Rates ◽  
Hydroxamic Acids ◽  
Phosphorus Compounds ◽  
Reaction Products ◽  
Electron Pairs ◽  
Alkyl Derivatives ◽  
Solvent Type ◽  
Electron Deficiency

The review analyzes issues related to the reactivity of nucleophiles and the manifestation of the α-effect in substitution processes at electron-deficient centers. The fundamental aspects of this phenomenon, as well as the possibilities and prospects of using α-nucleophiles in systems for the highly efficient degradation of substrates - ecotoxicants of various natures, are discussed. In the first part of the review such aspects were observed: inorganic α-nucleophiles as the most effective class of reagents for the decomposition of organic phosphorus compounds, hydroxylamine, its N-alkyl derivatives, oximes, and hydroxamic acids, reactivity of the НОО– anion in the processes of acyl group transfer, reactivity of oximate ions, inorganic α-nucleophiles as the basis of formulations for the degradation of neurotoxins, vesicants, and organophosphorus pesticides, design of inhibited acetylcholinesterase reactivators based on hydroxylamine derivatives, ways of structural modification of α-nucleophiles and systems based on them. The data on the reactivity of typical inorganic α-nucleophiles in the cleavage of acyl-containing substrates, including phosphorus acid esters, which provide abnormally high reaction rates in comparison with other supernucleophiles, are analyzed. Various types of such α-nucleophiles, features of their structure and reactivity are considered. It was shown that an important feature of hydroxylamine, oximes, and hydroxamic acids is the presence of a fragment with adjacent O and N (–N – O – H) atoms containing one or more lone electron pairs, which determines their belonging to the class of α-nucleophiles. It has been shown that a many of factors can be responsible for the manifestation of the α-effect and its magnitude, the main of which is the destabilization of the ground state of the nucleophile due to repulsion of lone electron pairs, stabilization of the transition state, the unusual thermodynamic stability of reaction products, solvation effects of the solvent, type of hybridization of the electrophilic center, etc.

scholarly journals Optimized Blood Volume Monitoring during Hemodialysis Procedure based on Ultrasonic Speed Measurement

2019 ◽  
Vol 9 (3Jun) ◽  
Author(s):  
V. R Nafisi ◽  
M Eghbal
Keyword(s):  
Measurement Method ◽  
Water Volume ◽  
Critical Threshold ◽  
Ultrasonic Speed ◽  
Air Bubble ◽  
Clinical Complications ◽  
Speed Measurement ◽  
Ultra Filtration ◽  
Concentration Changes ◽  
Hemodialysis Machine

Fast reduction of blood water volume due to ultra-filtration via hemodialysis machine and critical threshold of blood water volume can result in clinical complications such as hypotension. When blood water volume reduces during hemodialysis process, the concentration of blood forming elements will increase. One of the methods for the monitoring of the concentration changes is ultrasonic speed measurement.In this paper, we optimize the ultrasonic speed measurement method in such a way that it would be compatible with conventional air detector in a hemodialysis machine. Air bubble detecting and the relative blood water volume estimating can be achieved by adding the “sing-around” ultrasonic speed measurement method to the current hemodialysis machine; air bubble detection is achieved by monitoring the decline in the ultrasonic wave amplitude (because of air bubbles) and the protein concentration measurement is achieved by measuring the transit time of the wave. Therefore, the optimized method can be applied to the air detection device of a hemodialysis machine.

Evaluation of Biodegradability of Starch-Based Plastics

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2089-2092 ◽  
Author(s):  
U. J. Ndon ◽  
A. D. Levine ◽  
B. S. Bradley
Keyword(s):  
Starch Granules ◽  
Carbon Conversion ◽  
Anaerobic Conditions ◽  
Polyethylene Matrix ◽  
Molecular Weights ◽  
Total Percentage ◽  
Degradation Rates ◽  
Before And After ◽  
Biological Tests ◽  
Aerobic And Anaerobic

Four commercially produced starch based plastics manufactured by the addition of starch to polyethylene matrix were tested in the laboratory to measure their biodegradability under both aerobic and anaerobic conditions. Pure starch was also tested under identical conditions to compare rates and extent of degradation of starch in the plastics to that of pure starch. Plastics surface properties and weight average molecular weights were observed before and after biological tests using Scanning Electron Microscopy (SEM), and High-Temperature Gel-Permeation-liquid Chromatography (HT-GPC) (Lee et al., 1991) respectively. Degradation rates and total percentage of carbon conversion were higher under aerobic tests as compared to tests under anaerobic conditions. Overall carbon conversion in starch based plastics was less than that of pure starch. Surface analysis of the plastics indicated removal of some starch granules from the polyethylene matrix. Significant changes did not occur in the average molecular weights of the plastics from HT-GPC tests which indicated no degradation of the polyethylene matrix.

scholarly journals Organochlorine and Organophosphonis Pesticide Residues in Food from Egyptian Local Markets

1996 ◽  
Vol 79 (4) ◽  
pp. 949-952 ◽  
Author(s):  
Salwa M Dogheim ◽  
Sohair A Gad Alla ◽  
Sami M A El-Syes ◽  
Monir M Almaz ◽  
Emel Y Salama
Keyword(s):  
Pesticide Residues ◽  
Organophosphorus Pesticides ◽  
Organophosphorus Pesticide ◽  
Storage Period ◽  
Citrus Fruits ◽  
Fish Samples ◽  
Maximum Residue Limits ◽  
Before And After ◽  
Repeated Use ◽  
Agricultural Use

Abstract A market basket survey was conducted to monitor organochlorine and organophosphorus pesticide residues in potatoes, citrus fruits, and fish collected from local Egyptian markets. Maximum Residue Limits (MRLs) of the Codex Committee on Pesticide Residues for γ-hexachlorocyclohexane (HCH) in potatoes were exceeded in 8 samples and for DDT in 2 samples. The aging of HCH and DDT indicated a recent use of both pesticides during the potato storage period between cultivation seasons. However, such use is illegal because HCH mixture isomers (gammaxane) and DDT have been officially prohibited from agricultural use in Egypt since 1980. The highest residue levels of fenitrothion (3.8 ppm) in potatoes may be due to its repeated use before and after harvest. No organochlorine pesticide residues were found in citrus fruits. None of the detected organophosphorus pesticides exceeded their MRLs. HCH and DDT residue limits were exceeded in 5 and 7 fish samples, respectively, collected from 12 markets throughout the country. The heptachlor MRL was violated in only one fish sample (3.9 ppm).

The effect of insufficient effort responding on the validity of student evaluation of teaching

2019 ◽  
Vol 11 (3) ◽  
pp. 604-615
Author(s):  
Mahmoud AlQuraan
Keyword(s):  
Higher Education ◽  
Construct Validity ◽  
Teaching Effectiveness ◽  
Detection Method ◽  
Student Evaluation ◽  
Principal Component ◽  
Data Sets ◽  
Factorial Validity ◽  
Content Type ◽  
Before And After

Purpose The purpose of this paper is to investigate the effect of insufficient effort responding (IER) on construct validity of student evaluations of teaching (SET) in higher education. Design/methodology/approach A total of 13,340 SET surveys collected by a major Jordanian university to assess teaching effectiveness were analyzed in this study. The detection method was used to detect IER, and the construct (factorial) validity was assessed using confirmatory factor analysis (CFA) and principal component analysis (PCA) before and after removing detected IER. Findings The results of this study show that 2,160 SET surveys were flagged as insufficient effort responses out of 13,340 surveys. This figure represents 16.2 percent of the sample. Moreover, the results of CFA and PCA show that removing detected IER statistically enhanced the construct (factorial) validity of the SET survey. Research limitations/implications Since IER responses are often ignored by researchers and practitioners in industrial and organizational psychology (Liu et al., 2013), the results of this study strongly suggest that higher education administrations should give the necessary attention to IER responses, as SET results are used in making critical decisions Practical implications The results of the current study recommend universities to carefully design online SET surveys, and provide the students with clear instructions in order to minimize students’ engagement in IER. Moreover, since SET results are used in making critical decisions, higher education administrations should give the necessary attention to IER by examining the IERs rate in their data sets and its consequences on the data quality. Originality/value Reviewing the related literature shows that this is the first study that investigates the effect of IER on construct validity of SET in higher education using an IRT-based detection method.

scholarly journals Direct Use of the Savitzky–Golay Filter to Develop an Output-Only Trend Line-Based Damage Detection Method

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1983 ◽  
Author(s):  
Hadi Kordestani ◽  
Chunwei Zhang
Keyword(s):  
Damage Detection ◽  
Detection Method ◽  
Moving Load ◽  
Velocity Variation ◽  
Trend Line ◽  
Damage Scenarios ◽  
Acceleration Data ◽  
Before And After ◽  
Output Only ◽  
Direct Use

The Savitzky–Golay filter (SGF) is a time-domain technique that determines a trend line for a signal. The direct application of SGF for damage localization and quantification is investigated in this paper. Therefore, a single-stage trend line-based damage detection method employing SGF is proposed in which the damage is located and quantified at the bridge under moving load. A simply supported beam under moving sprung mass is numerically simulated to verify the proposed method. Four different velocities and five different single- and multi-damage scenarios are considered. The acceleration data along the beam are obtained, manually polluted with noise and their trend lines are then determined using SGF. The results show that the proposed method can accurately locate and quantify the damage using these trend lines. It is proved that the proposed method is insensitive to the noise and velocity variation in which having a constant velocity is a hard task before and after damage. Additionally, defining a normalization factor and fitting a Gaussian curve to this factor provide an estimation for the baseline and therefore, it categorizes the proposed method as baseline-free method.

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