scholarly journals Effects of a dicamba/MCPA/mecoprop herbicide mixture on the leaves of a barley variety

1978 ◽  
Vol 50 (3) ◽  
pp. 183-195
Author(s):  
Helena Savolainen ◽  
Kaarina Pihakaski
Keyword(s):  
Toxic Effects ◽  
Mesophyll Cells ◽  
Cell Structures ◽  
Different Temperatures ◽  
Herbicide Mixture ◽  
Higher Temperature ◽  
Electron Microscopes ◽  
Total Observation ◽  
Short Time ◽  
Observation Period

Plants of a barley cultivar Pomo were sprayed at 2-node stage with a herbicide mixture, ’Mepro Special’, containing dicamba, MCPA and mecoprop, and the plants were grown at two different temperatures. 15°C and 23° C. The effects of the herbicide on the morphology and anatomy were studied by light and electron microscopes and the effects on the chlorophyll content of leaves were studied at various intervals after the spraying. First sign of damage in the morphology of plants grown both at 23° C and 15°C were observable 10-12 days after the spraying but those in the ultrastructure as soon as 1 day after the treatment. The cells of the vascular bundle sheath were most sensitive while the mesophyll cells were unchanged during the total observation period of 12 days at 15°C. At a higher temperature injuries of various stages were observable also in the mesophyll 6 days after the treatment. The clearest alterations became visible in the chloroplasts. They swelled to spherical in shape, the intergrana and later also grana lamellae formed vesicles by dilating, later they broke down, and ultimately the plastid envelope disintegrated. The amount of starch and chlorophyll decreased, whereas the number and size of osmiophilic plastoglobuli increased significantly. The mitochondria swelled, the cristae frequently disappeared and the outer membrane of the envelope distended largely. The nucleus was best capable of resisting the toxic effects of the herbicide. The tonoplast and plasmalemma were broken down a short time before the final disintegration of the cell structures. High temperature obviously reinforced the toxic effects of the herbicide mixture.

An Analysis of the Temperature Dependence of Photosynthesis Considering the Kinetics of RuP2 Carboxylase and the Pool of RuP2 in Intact Leaves

1988 ◽  
Vol 15 (6) ◽  
pp. 737 ◽  
Author(s):  
VM Oja ◽  
BH Rasulov ◽  
AH Laisk
Keyword(s):  
Temperature Dependence ◽  
Short Exposure ◽  
Co2 Uptake ◽  
Mesophyll Conductance ◽  
Mesophyll Cells ◽  
Binding Reaction ◽  
Cotton Plants ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Kinetics Of

Sunflower and cotton plants were grown in growth boxes at 460 �mol m-2 s-1. The mesophyll conductance in N2, the assimilatory charge (post-illumination CO2 uptake) and the CO2 capacity (the solubility of CO2 + HCO3- + CO32-) were measured at different temperatures. The mesophyll conductance had its maximum at 29-30°C in sunflower leaves and rapidly declined at higher and lower temperatures. In cotton, the maximum occurred at a somewhat higher temperature. The assimilatory charge changed in parallel with the mesophyll conductance. When the assimilatory charge was measured after a short exposure to CO2-free N2, it remained constant at lower temperatures and declined only at superoptimal temperatures. As the assimilatory charge reflects the RuP2 pool in the leaf, the temperature dependence of the mesophyll conductance at a constant assimilatory charge reveals the actual activation energy of the CO2 binding reaction of carboxylase (together with the CO2 transport conductance in the liquid phase of mesophyll cells) which was 29 kJ mol-� for both species. At superoptimal temperatures, the primary cause for the reversible decrease of photosynthesis was a decrease in the assimilatory charge (RuP2 pool). The decrease cannot be caused by an inadequate rate of RuP2 resynthesis but is, presumably, the result of either too rapid drainage of triosephosphates to the cytosol from chloroplasts or de-energisation of thylakoids at high temperatures.

scholarly journals Amide-Type Substrates in the Synthesis of N-Protected 1-Aminomethylphosphonium Salts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 552
Author(s):  
Dominika Kozicka ◽  
Paulina Zieleźny ◽  
Karol Erfurt ◽  
Jakub Adamek
Keyword(s):  
Reaction Times ◽  
The Other ◽  
Hydroxyl Group ◽  
Other Hand ◽  
Step Procedure ◽  
Higher Temperature ◽  
Short Time ◽  
Work Up

Herein we describe the development and optimization of a two-step procedure for the synthesis of N-protected 1-aminomethylphosphonium salts from imides, amides, carbamates, or lactams. Our “step-by-step” methodology involves the transformation of amide-type substrates to the corresponding hydroxymethyl derivatives, followed by the substitution of the hydroxyl group with a phosphonium moiety. The first step of the described synthesis was conducted based on well-known protocols for hydroxymethylation with formaldehyde or paraformaldehyde. In turn, the second (substitution) stage required optimization studies. In general, reactions of amide, carbamate, and lactam derivatives occurred at a temperature of 70 °C in a relatively short time (1 h). On the other hand, N-hydroxymethylimides reacted with triarylphosphonium salts at a much higher temperature (135 °C) and over longer reaction times (as much as 30 h). However, the proposed strategy is very efficient, especially when NaBr is used as a catalyst. Moreover, a simple work-up procedure involving only crystallization afforded good to excellent yields (up to 99%).

scholarly journals Effect of calcination temperature and calcination time on the kaolinite/tio2 composite for photocatalytic reduction of CO2

2012 ◽  
Vol 58 (4) ◽  
pp. 10-22 ◽  
Author(s):  
Martin Reli ◽  
Kamila Kočí ◽  
Vlastimil Matějka ◽  
Pavel Kovář ◽  
Lucie Obalová
Keyword(s):  
Crystallite Size ◽  
Physical Adsorption ◽  
Photocatalytic Reduction ◽  
Thermal Hydrolysis ◽  
Calcination Time ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Titanyl Sulphate ◽  
Reduction Of Co2 ◽  
Hydrolysis Of

Abstract The kaolinite/TiO2 composite (60 wt% of TiO2) was prepared by thermal hydrolysis of a raw kaolin suspension in titanyl sulphate and calcined at different temperatures (600, 650 and 700°C) and for different times (1, 2 and 3 h). The obtained samples were characterized by XRPD, N2 physical adsorption and SEM, and tested for photocatalytic reduction of CO2. The different calcination conditions did not influence TiO2 phase composition, only slightly changed the specific surface area, and significantly affected crystallite size of kaolinite/TiO2 composite. A higher temperature and longer duration of calcination lead to higher crystallinity of the powder. The photocatalytic results showed that the crystallite size determined the efficiency of kaolinite/TiO2 photocatalysts.

scholarly journals Synthesis of Fe3O4 and Fe2O3 nanoparticles using hybrid electrochemical-thermal method

2020 ◽  
Vol 55 (3) ◽  
pp. 221-228
Author(s):  
HA Simol ◽  
R Sultana ◽  
M Y A Mollah ◽  
MS Miran
Keyword(s):  
Iron Oxide ◽  
Total Pore Volume ◽  
Thermal Method ◽  
Prepared Compound ◽  
Xrd Pattern ◽  
Spectral Techniques ◽  
Different Temperatures ◽  
Ft Ir ◽  
Higher Temperature ◽  
Lower Temperature

Nanocrystalline Fe3O4 and Fe2O3 particles were successfully synthesized by an innovative hybrid electrochemical-thermal method. The as-prepared compound was calcined for an hour from 100 to 600oC temperatures. The crystallinity, morphology and chemical state of the synthesized powders were characterized by XRD, TG-DTA, SEM/EDS, FT-IR, and UV–Vis spectral techniques after calcinations. The Brunauer–Emmett–Teller (BET) plots confirmed that iron oxide nanoparticles (NPs) calcined at 400oC has a surface area of 18.28 m2 g-1 with a total pore volume of 0.2064 cc g-1. From XRD pattern it is revealed that the precursor calcined at lower temperature (100-400oC) correspond to Fe3O4,while the ones calcined at higher temperature follow Fe2O3 pattern. The morphology of iron oxide NPs calcined at different temperatures were studied with scanning electron microscope (SEM) and exhibits spherical shaped geometries with average diameters of 80-150nm. Bangladesh J. Sci. Ind. Res.55(3), 221-228, 2020

scholarly journals Hydrothermal Carbonization Brewer’s Spent Grains with the Focus on Improving the Degradation of the Feedstock

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3226 ◽  
Author(s):  
Pablo Arauzo ◽  
Maciej Olszewski ◽  
Andrea Kruse
Keyword(s):  
Water Content ◽  
Liquid Product ◽  
Reaction Times ◽  
Hydrothermal Carbonization ◽  
Heating Value ◽  
High Heating Value ◽  
Acid Addition ◽  
Spent Grains ◽  
Different Temperatures ◽  
Higher Temperature

Hydrochar is a very interesting product from agricultural and food production residues. Unfortunately, severe conditions for complete conversion of lignocellulosic biomass is necessary, especially compared to the conversion of sugar compounds. The goal of this work is to improve the conversion of internal carbohydrates by application of a two-steps process, by acid addition and slightly higher water content. A set of experiments at different temperatures (180, 200, and 220 °C), reaction times (2 and 4 h), and moisture contents (80% and 90%) was performed to characterize the solid (high heating value (HHV), elemental) and liquid product phase. Afterwards, acid addition for a catalyzed hydrolysis reaction during hydrothermal carbonization (HTC) and a two-steps reaction (180 and 220 °C) were tested. As expected, a higher temperature leads to higher C content of the hydrochar and a higher fixed carbon (FC) content. The same effect was found with the addition of acids at lower temperatures. In the two-steps reaction, a primary hydrolysis step increases the conversion of internal carbohydrates. Higher water content has no significant effect, except for increasing the solubility of ash components.

scholarly journals Prevalence, magnitude, and incidence of labial gingival recession with Herbst-multibracket appliance treatment: A retrospective cohort study

2019 ◽  
Vol 89 (4) ◽  
pp. 535-543 ◽  
Author(s):  
Niko C. Bock ◽  
Julia Ruehl ◽  
Sabine Ruf
Keyword(s):  
Cohort Study ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Gingival Recession ◽  
Class Ii ◽  
Before And After ◽  
Total Observation ◽  
Multibracket Appliance ◽  
Lower Incisors ◽  
Observation Period

ABSTRACT Objective: To assess the prevalence and magnitude of labial gingival recession (LGR) before and after as well as the incidence during Class II:1 Herbst-Multibracket appliance (Herbst-MBA) treatment (Tx) plus retention in a retrospective cohort study. Materials and Methods: Records of Class II:1 patients who completed Herbst-MBA Tx (mean pre-Tx age 14.4 years) at Department of Orthodontics, University of Giessen, Giessen, Germany were analyzed. Tx consisted of a Herbst phase (mean 8.1 months) and a subsequent MBA phase (mean 16.1 months). Study casts from before and after Herbst-MBA Tx plus ≥24 months of retention were evaluated. Results: A total of 460 pre-Tx and 222 postretention study casts were available (total observation period: 59.2 ± 14.8 months). The overall prevalence for teeth with LGR ≥0.5 mm was 1.1% pre-Tx and 5.3% postretention. The highest prevalence of up to 5.3% (pre-Tx) and 16.4% (postretention) were seen for the lower incisors. Overall, the median magnitude of LGR was 0.0 mm pre-Tx/postretention (mean: 0.05 mm/0.08 mm). Incidence values of 4.0% (all teeth) and 10.0% to 11.4% (lower central incisors) were calculated for LGR ≥0.5 mm. Conclusions: The prevalence of LGR ≥0.5 mm increased from, on average, 1.1% to 5.3% during ≈6 years of Herbst-MBA Tx plus retention. The highest incidence was seen in lower incisors (10.0%–11.4%). However, because of the overall mean magnitude of 0.08 mm postretention, the clinical relevance can be considered as insignificant.

A Thermodynamic Model for Nearest-Neighbor Distributions in Annealed Quaternary Alloys

2011 ◽  
Vol 383-390 ◽  
pp. 768-773
Author(s):  
Li Li Tang ◽  
Chun Bo Wang
Keyword(s):  
Nearest Neighbor ◽  
Blue Shift ◽  
Type Conversion ◽  
Quaternary Alloys ◽  
Separation Result ◽  
Atomic Relaxation ◽  
Long Time ◽  
Higher Temperature ◽  
Induced Changes ◽  
Short Time

We focus on the annealing-induced changes of N-centered nearest-neighbor (NN) entironment in Ga1-xlnxNyAs1-y quaternary alloys and present a statistical distributing model of the binary bonds under thermodynamics equilibrium state. The core of this model is the assumption that the phase separation result of equimolar system at T=0 K is “ + ”, in which the effect of strain has been ignored. We propose two mechanisms for annealing: (i) Atomic relaxation lead to a total energy minimum. (ii) The type conversion of bond configuration is the main reason for the remarkable blue shift. Then parameter r, the number of NN In atoms per N atom, is calculated. We find that the theoretical NN distributions strain is in good agreement with former studies. It can be concluded that the blue shift induced by long-time annealing at low temperature is able to be equal with that induced by short-time annealing at higher temperature. The results are close to recent investigations. But an allegorical linear relation between band gap and composition (x, y) is still in question.

Mammographic Fine Needle Biopsy of Non-Palpable Breast Lesions

1984 ◽  
Vol 25 (4) ◽  
pp. 273-276 ◽  
Author(s):  
M. Kehler ◽  
U. Albrechtsson
Keyword(s):  
Diagnostic Accuracy ◽  
Needle Biopsy ◽  
Fine Needle Biopsy ◽  
Breast Lesions ◽  
Malignant Cells ◽  
Fine Needle ◽  
The Past ◽  
Palpable Breast ◽  
Short Time ◽  
Observation Period

Results with a previously described device for fine needle biopsies of non-palpable breast lesions are reported. During the past 5 years 182 biopsies were performed and 133 of these yielded diagnostic cell material. In the series, 41 carcinomas were found and fine needle biopsy in all demonstrated malignant or probably malignant cells. In the biopsies evaluated as benign or probably benign, malignancy has not been found during the observation period of 4 to 59 months (mean 21.5 months). The device described is cheap and biopsy is easily performed and, if necessary, repeated in a short time. The diagnostic accuracy is high and carcinomas as small as 3 mm in diameter have been diagnosed.

scholarly journals Analysis of a Lab-Scale Heat Transformation Demonstrator Based on a Gas–Solid Reaction

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2234 ◽  
Author(s):  
Jana Stengler ◽  
Julius Weiss ◽  
Marc Linder
Keyword(s):  
Experimental Studies ◽  
Hydration Reaction ◽  
Solid Reaction ◽  
Discharge Performance ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Solid Bulk ◽  
Heat Transformation ◽  
Modelling Approach ◽  
Gas Solid Reaction

Heat transformation based on reversible chemical reactions has gained significant interest due to the high achievable output temperatures. This specific type of chemical heat pump uses a reversible gas–solid reaction, with the back and forward reactions taking place at different temperatures: by running the exothermic discharge reaction at a higher temperature than the endothermic charge reaction, the released heat is thermally upgraded. In this work, we report on the experimental investigation of the hydration reaction of strontium bromide (SrBr2) with regard to its use for heat transformation in the temperature range from 180 °C to 250 °C on a 1 kg scale. The reaction temperature is set by adjusting the pressure of the gaseous reactant. In previous experimental studies, we found the macroscopic and microscopic properties of the solid bulk phase to be subject to considerable changes due to the chemical reaction-. In order to better understand how this affects the thermal discharge performance of a thermochemical reactor, we combine our experimental work with a modelling approach. From the results of the presented studies, we derive design rules and operating parameters for a thermochemical storage module based on SrBr2.

Synthesis and Characterization of Multi-Angular Branched ZnO Microstructures and Peculiar Nanopushpins Obtained by Thermal Treatment from Compacted ZnS Powder

2019 ◽  
Vol 286 ◽  
pp. 23-30
Author(s):  
J.R. Mora ◽  
Gregorio Flores-Carrasco ◽  
Mauricio Pacio ◽  
T.G. Díaz-Rodríguez ◽  
Hector Juárez
Keyword(s):  
Thermal Treatment ◽  
Treatment Process ◽  
Treatment Temperature ◽  
Complex Structures ◽  
Wurtzite Phase ◽  
Free Process ◽  
Different Temperatures ◽  
Short Time ◽  
Hexagonal Wurtzite Phase

Multi-angular branched ZnO microstructures with rods-shaped tips and nanopushpins with hexagonal cap on top have been synthesized by a simple thermal treatment process of compacted ZnS powder used as starting material and substrate. The structures have been grown at different temperatures (800, 900 and 1000 °C) for 60 min, in a constant nitrogen environment at atmospheric pressure via a catalyst-free process. XRD results of the as-grown products from ZnS powder show a significant reduction in the cubic zincblende phase to the hexagonal wurtzite phase with the increase of treatment temperature, as compared to the bulk value. Post-anneal analyses indicated that the transformation of morphologies of the as-grown structures also depends strongly on the treatment temperature. The proposed method represents an easy and economical way to grow complex structures of ZnO, with a relatively short time, furthermore, without the neediness of use an external substrate to grow. These new and interesting nanostructures have potential in applications such as optoelectronics.

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