32 research outputs found
Digital Mapping of Surface and Subsurface Soil Organic Carbon and Soil Salinity Variation in a Part of Qazvin Plain (Case Study: Abyek and Nazarabad Regions)
IntroductionKnowledge of the spatial distribution of soil salinity and soil organic carbon (SOC) leads to obtaining valuable information that is effective in decision-making for agricultural activities. More than a third of the world's land is affected by salt, which threatens the growth and production of crops, and prevents the development of sustainable agriculture. The high electrical conductivity (EC) content in soils poses significant challenges in arid and semi-arid regions, greatly impacting agricultural production. Saline and sodic soils often exhibit high levels of sodium which is a key characteristic. The presence of sodium ions leads to the destabilization of soil aggregates and the dispersion of soil particles resulting in the closure of soil pores. Consequently, unfavorable changes occur in the soil physical, chemical, and biological properties increasing its susceptibility to water and wind erosion. Additionally, high sodium levels can lead to the decomposition of soil organic carbon (SOC). SOC is crucial for water retention, cation exchange, and nutrient availability, making its reduction in agricultural soils a significant threat to sustainable soil management. Therefore, the investigation of soils in terms of EC and SOC contents and their spatial distribution is of great importance to support decision-makers in agricultural development planning to reduce challenges related to food security in arid and semi-arid regions.Materials and MethodsThis study was conducted with the aim of investigating the EC and SOC in topsoil (0-30 cm) and subsoil (30-60 cm) layers using four machine learning (ML) algorithms namely, random forest (RF), decision tree (DTr), support vector regression (SVR) and artificial neural network (ANN) performed in Qazvin Plain. The study area includes a part of agricultural lands and natural areas of Alborz and Qazvin provinces, between the Nazarabad and Abyek cities in Iran. This region with an area of 60,000 hectares is located at latitude 35° 54´ to 36° 54´ to the north and 50° 15´ to 50° 39´ to the east. This research was carried out in four stages including (i) soil sampling and measuring the physical and chemical properties of the soil and preparation of environmental covariates from a digital elevation model (DEM) with spatial resolution 12.5 m and Landsat 8 satellite imagery with spatial resolution 30 m by SAGA GIS and ENVI software, (ii) spatial modeling of soil EC and SOC in the topsoil and subsoil layers by the RF, SVR, ANN, and DTr ML algorithms, (iii) evaluating the efficiency of the ML algorithms and determining the relative importance of environmental covariates, and (iv) preparation of spatial prediction maps of EC and SOC in the topsoil (0-30 cm) and subsoil (30-60 cm) layers in the study area.Results and Discussion The result of the spatial prediction maps of EC showed that the studied area has non-saline to very saline soils up to a depth of 60 cm. It is also possible that the EC equivalent shows a decreasing trend in soil salinity with a depth from 6.05 to 5.55 ds/m from the topsoil to the subsoil layer. The highest amount of SOC was observed in the surface layer equal to 3.3%. Globally SOC content decreased from the surface (average of 0.84%) to depth (average of 0.4%). The high spatial variability of SOC showed that the soils of the study area are affected by management activity. Environmental covariates were extracted as a proxy of topography and remote sensing indices including elevation, diffuse Insolation (Diffuse), Multi-Resolution Index of Valley Bottom Flatness (MrVBF), Normalized Differences Vegetation Index (NDVI), SAGA wetness index (SWI) and wind Effect (WE) were used as representatives of soil formation factors. The topography parameters, including the elevation, diffuse insolation, and Multi-Resolution Index of Valley Bottom Flatness, were most closely related to EC and SOC variations in each topsoil and subsoil layer. Elevation can be justified around 50% and 35% of EC and 28.56% and 29.47% of SOC variations in the topsoil and subsoil layers, respectively, followed by the diffuse variable can succeed to justified 19.7% and 25.1% of EC and 27.28% and 27.67% of SOC spatial variations in the topsoil and subsoil layers, respectively.The results confirmed that the RF was recognized as outperforming the ML model for predicting EC in the topsoil (R2 =0.74, RMSE =0.36, and nRMSE= 0.07), as well as predicting SOC in topsoil and subsoil layers (R2= 90 and R2=0.80), followed by the DTr for predicting EC (R2 0.77, RMSE/0.9, and nRMSE 0.17) in the subsoil layer in comparison other models. Conclusion The RF (Random Forest) and DTr (Decision Tree) models incorporating topographic parameters demonstrated satisfactory accuracy in predicting the variation of topsoil and subsoil electrical conductivity (EC) and soil organic carbon (SOC) in the study area. Topography plays a crucial role in soil formation, and elevation-based topographic attributes are commonly used as key predictors in digital soil mapping projects. The variability in topography influences water flow and sedimentation processes which, in turn, affects soil development and the spatial distribution of soil properties. The resulting soil maps can be valuable tools for decision-making programs related to soil management in the region
Carbon dioxide hydrogenation over the carbon-terminated niobium carbide (111) surface: a density functional theory study
Carbon dioxide (CO2) hydrogenation is an energetic process which could be made more efficient through the use of effective catalysts, for example transition metal carbides. Here, we have employed calculations based on the density functional theory (DFT) to evaluate the reaction processes of CO2 hydrogenation to methane (CH4), carbon monoxide (CO), methanol (CH3OH), formaldehyde (CH2O), and formic acid (HCOOH) over the carbon-terminated niobium carbide (111) surface. First, we have studied the adsorption geometries and energies of 25 different surface-adsorbed species, followed by calculations of all of the elementary steps in the CO2 hydrogenation process. The theoretical findings indicate that the NbC (111) surface has higher catalytic activity towards CO2 methanation, releasing 4.902 eV in energy. CO represents the second-most preferred product, followed by CH3OH, CH2O, and HCOOH, all of which have exothermic reaction energies of 4.107, 2.435, 1.090, and 0.163 eV, respectively. Except for the mechanism that goes through HCOOH to produce CH2O, all favourable hydrogenation reactions lead to desired compounds through the creation of the dihydroxycarbene (HOCOH) intermediate. Along these routes, CH3* hydrogenation to CH4* has the highest endothermic reaction energy of 3.105 eV, while CO production from HCO dehydrogenation causes the highest exothermic reaction energy of −3.049 eV. The surface-adsorbed CO2 hydrogenation intermediates have minimal effect on the electronic structure and interact only weakly with the surface. Our results are consistent with experimental observations
C-Terminal Domain Deletion Enhances the Protective Activity of cpa/cpb Loaded Solid Lipid Nanoparticles against Leishmania major in BALB/c Mice
Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis with an annual incidence of approximately 2 million cases and is endemic in 88 countries, including Iran. CL's continued spread, along with rather ineffectual treatments and drug-resistant variants emergence has increased the need for advanced preventive strategies. We studied Type II cysteine proteinase (CPA) and Type I (CPB) with its C-terminal extension (CTE) as cocktail DNA vaccine against murine and canine leishmaniasis. However, adjuvants' success in enhancing immune responses to selected antigens led us to refocus our vaccine development programs. Herein, we discuss cationic solid lipid nanoparticles' (cSLN) ability to improve vaccine-induced protective efficacy against CL and subsequent lesion size and parasite load reduction in BALB/c mice. For this work, we evaluated five different conventional as well as novel parasite detection techniques, i.e., footpad imaging, footpad flowcytometry and lymph node flowcytometry for disease progression assessments. Vaccination with cSLN-cpa/cpb-CTE formulation showed highest parasite inhibition at 3-month post vaccination. Immunized mice showed reduced IL-5 level and significant IFN-ã increase, compared to control groups. We think our study represents a potential future and a major step forward in vaccine development against leishmaniasis
Review on superglue eye injuries è¶ å¼ºå��è�¶ç�¼é�¨æ��伤ç��ç �究è¿�å±�
The purpose of this study is to run a review on possible superglue injuries to the eye. In this review, previous papers regarding the harmful impacts of superglue were systematically studied. Superglue eye injuries have been common during the three last decades and most of them were accidental and preventable by introducing safety issues and although it may be toxic for the tissues, it is not associated with long term morbidity. This paper addresses the management of superglue injuries and shows the importance of the prevention of ocular superglue injuries. Copyright 2020 by the IJO Press
Kwitnienie i mikropropagacja in vitro lisianthusa (Eustoma grandiflorum) w reakcji na regulatory wzrostu roslin (NAA i BA)
In vitro flowering and micropropagation are useful for plant breeding programs and commercial production of important ornamental plants. In vitro conditions including media components, kind, concentration and ratio of plant growth regulators and culture conditions significantly affect in vitro flowering and micropropagation. There is no any report dealing with the in vitro flowering of Lisianthus (Eustoma grandiflorum). Here, a protocol was developed for flowering and high frequency in vitro micropropagation of E. grandiflorum, an ornamental plant. Micropropagation is an effective tools for propagation of ornamental plants in large scale. The aim of the present study was to evaluate the effect of different concentrations of NAA and BA on micropropagation and flowering of Lisianthus, in vitro. Used culture medium was MS enriched with 0, 0.1, 0.2 and 2 mg L-1 of NAA and BA. In establishment process of explants, the most shoot length (2.07 cm per plant) was obtained on medium supplemented with 0.1 mg L-1 BA (without NAA). Maximum shoot number (5.80 per plant) was produced in medium containing 0.1 mg L-1 BA along with 0.2 mg L-1 NAA. Bud explants in culture media containing 0.2 mg L-1 NAA (without BA) and 0.1 mg L-1 NAA along with 2 mg L-1 BA produced maximum node number (3.20 per plant). The largest number of root (14.53 per plant) and root length (3.87 cm per plant) were produced on 0.2 mg L-1 NAA without BA, also 0.2 mg L-1 BA plus 0.2 mg L-1 NAA and 0.2 mg L-1 BA without NAA. Explants produced flower on medium containing 0.1 mg L-1 BA along with 0.1 mg L-1 NAA without transition of callus formation. Flower was produced from callus in medium containing 0.1 mg L-1 BA along with 2 mg L-1 NAA. Regenerated plants showed 98% survival in greenhouse during acclimatization. Acclimatized plants were morphologically similar to the mother plants.Kwitnienie i mikropropagacja in vitro są użyteczne w programach hodowli roślin oraz produkcji komercyjnej ważnych roślin ozdobnych. Warunki in vitro, łącznie ze składnikami pożywek, rodzajem, stężeniem oraz proporcją regulatorów wzrostu roślin, a także warunkami hodowli, w sposób istotny wpływają na kwitnienie i mikropropagację in vitro. Nie istnieje żadne badanie dotyczące kwitnienia in vitro lisanthiusa (Eustoma grandiflorum). W niniejszym badaniu opracowano kwitnienie i wysoką częstotliwość mikropropagacji in vitro dla E. grandiflorum, który jest rośliną ozdobną. Mikropropagacja jest skutecznym narzędziem rozmnażania roślin ozdobnych na dużą skalę. Celem niniejszego badania była ocena wpływu różnych stężeĔ NAA i BA na mikropropagację i kwitnienie lisianthiusa in vitro. Używana pożywka hodowlana została wzbogacona za pomocą 0; 0,1; 0,2 i 2 mg L-1 NAA i BA. Przy powstawaniu eksplantów największa długość łodygi (2,07 cm na roślinę) była uzyskana na pożywce uzupełnionej o 0,1 mg L-1 BA (bez NAA). Maksymalna liczba łodyg (5,80 na roślinę) została wytworzona na pożywce zawierającej 0,1 mg L-1 BA wraz z 0,2 mg L-1 NAA. Eksplanty pączków na pożywce hodowlanej zawierającej 0,2 mg L-1 NAA (bez BA) oraz 0,1 mg L-1 NAA wraz z 2 mg L-1 BA wytworzyły maksymalną liczbę węzłów (3,20 na roślinę). Największą liczbę korzeni (14,53 na roślinę) oraz największą długość korzenia (3,87 na roślinę) zaobserwowano na 0,2 mg L-1 NAA bez BA jak również 0,2 mg L-1 BA plus 0,2 mg L-1 NAA oraz 0,2 mg L-1 BA bez NAA. Eksplanty tworzyły kwiat na pożywce zawierającej 0,1 mg L-1 BA wraz z 0,1 mg L-1 NAA bez przeniesienia kalusa. Kwiat był tworzony z kalusa na pożywce zawierającej 0,1 mg L-1 BA wraz z 2 mg L-1 NAA. Zregenerowane rośliny wykazały 98% przeżycie w szklarni podczas aklimatyzacji. Zaaklimatyzowane rośliny były morfologicznie podobne to swych roślin macierzystych
Influence of nozzle configuration and particle size on characteristics and sliding wear behaviour of HVAF-sprayed WC-CoCr coatings
In this study, effect of feedstock particle size and nozzle configuration on deposition, microstructural features, hardness and sliding wear behaviour of high velocity air fuel (HVAF)-sprayed WC-CoCr coatings was evaluated. Three different WC-CoCr powders with nominal particle sizes of 5/20 μm (fine), 5/30 μm (medium) and 15/45 μm (coarse) were sprayed employing a HVAF gun with four distinct DeLaval nozzle configurations involving different lengths and/or exit diameters. Microstructure, phase constitution and mechanical characteristics of the coatings were evaluated using SEM, EDS, XRD and micro indentation testing. Specific wear rate for all the samples was determined under sliding conditions and a comprehensive post wear analysis was conducted. X-ray diffraction analysis showed negligible decarburization in all the HVAF-sprayed coatings. It was shown that decrease in particle size of employed feedstock results in discernible changes in microstructural features of the coatings as well as considerable improvement in their performance. Also, notable changes in wear mechanisms were identified on reducing particle size from coarse to medium or fine. Fine and coarse feedstock powders were found to be sensitive to the type of nozzle used while no major difference was observed in coatings from powders with medium cut size sprayed with different nozzles
Tribological behavior of HVAF-sprayed WC-based coatings with alternative binders
The tribological performance of High Velocity Air-Fuel (HVAF) sprayed WC-based cermet coatings with binders containing no or very limited amount of cobalt was evaluated under dry sliding, erosion, and abrasion wear conditions. The wear and corrosion behaviors of WC-NiMoCrFeCo, WC-FeNiCrMoCu and WC-FeCrAl HVAF sprayed coatings were investigated and compared to standard WC-CoCr coatings as benchmark. Microstructure characterization along with XRD analysis was conducted on all powders as well as the corresponding coatings. Comprehensive post wear analysis was conducted on all coatings subjected to ball-on-disk, gas jet erosion and dry sand-rubber wheel abrasion tests. Moreover, all coatings were exposed to 3.5% (wt./vol.) NaCl aqueous solution to evaluate their corrosion performance through electrochemical testing. XRD results showed negligible phase transformation between the powders and the deposited coatings. The WC-NiMoCrFeCo coating exhibited the best sliding wear and electrochemical corrosion performance, with an average specific wear rate value of 3.1 × 10−8 (mm3·N−1·m−1) and a corrosion current density of 1.9 μA/cm2. This coating also showed comparable abrasive wear resistance to the WC-CoCr coating. Under erosive wear conditions, too, the WC-FeNiCrMoCu and WC-FeCrAl coatings showed a comparable performance to the benchmark. Dominant wear mechanisms for the reference WC-CoCr coating, under sliding wear conditions, were abrasion (deep grooving) and surface fatigue (crack propagation and pitting). On the contrary, no pitting was observed in WC-NiMoCrFeCo and WC-FeCrAl coatings during the sliding wear test. No considerable difference was identified in the wear mechanisms of the different coatings under abrasion and erosion wear conditions. The results highlight the promise of some of the environment friendly binders studied to replace Co
Cardioprotective Effect Of Dichloromethane Valerian (Valeriana Officinalis) Extract On Ischemia-Reperfusion-Induced Cardiac Injuries In Rats
Background. Valepotriate is an active ingredient of valerian (Valeriana officinalis) with strong antioxidant activity that is effective for numerous cardiovascular diseases. Objective. The aim of this study was to investigate the effect of an active ingredient of V. officinalis extract on ischemia-reperfusion-induced cardiac injuries in male rats. Methods. Thirty-two male rats were subjected to ischemia for 40 minutes and reperfusion for five days. The rats were divided into 4 groups of 8 each; group 1 (control) was given normal saline, and groups 2-4 were gavaged with 0.2, 0.1, 0.05 mg/kg of valepotriate extract, respectively, and received extract (0.2 mg/kg ip) two weeks before ischemia induction. Results. Dichloromethane V. officinalis (valepotriate) extract exerted a protective effect against ischemia-reperfusion-induced injuries. So that infarct size and number of ventricular arrhythmia and ventricular escape beats decreased compared to the control group. Moreover, ST segment amplitude, QTC interval, and heart rate decreased in the injured hearts and serum levels of antioxidant enzymes glutathione peroxidase, catalase, and superoxide dismutase increased. Biochemical markers malondialdehyde and lactate dehydrogenase also decreased on day 5 after the onset of reperfusion. Conclusion. V. officinalis extract may have a protective effect against myocardial ischemia-reperfusion by producing antioxidant effects