The effects of different compositions of growth media on the development of microplants of the Solnechny potato variety

The results of studying the effect of nutrient media of various compositions on the growth of improved micro-plants of potatoes of the Solnechny variety grown under laboratory conditions in vitro are presented. Six compositions of the nutrient medium were studied: standard Murashige-Skuga medium modified for micropropagation (considered as a control), modified Murashige-Skuga medium with a reduced content of mineral components (up to 1/2 and up to 1/3), modified Murashige-Skuga medium with an increased content of agar-agar (10 g/l), modified Murashige-Skuga medium with a reduced content of agar-agar (4 g/l), Murashige-Skuga medium modified with the addition of 3 mg/L giberrellinic acid and 1 mg/L indoliacetic acid. The following parameters of cultivated plants were taken into account: plant length, root presence, number of internodes, total plant mass, leaf mass, root mass, leaf plate surface area. The use of modified nutrient media with a reduced content of mineral components led to an increase in plant length (by 28-30%), stem mass (by 25%) due to leaf mass (by 18%) and stem mass (by 31%) and the total surface area of leaf plates (by 12%). In the variant using a medium with 1/3 mineral components an increase in the mass of the root system was observed (by 20%). When growing plants on a modified nutrient medium with a high content of agar-agar, a decrease in the length of plants (by 6%), a decrease in the mass of the scion (by 12%) due to a decrease in the mass of the stem (by 15%) was observed. Plants grown on a modified nutrient medium with a reduced content of agar-agar were distinguished by a larger mass of the root system (by 10%), scion (by 17%) (due to an increase in leaf mass (by 27%), as well as the total surface area of leaf plates (by 22%). When growth regulators (giberrellin and indoliacetic acid) were added to the modified nutrient medium, a significant increase in plant height (by 70%), a decrease in the mass of the root system (by 50%) and leaves (by 46%), and an increase in the mass of the stem (by 23%) were observed. The total leaf surface area was 28% lower than the control values. For accelerated micropropagation of improved potato plants of the Solnechny variety and preparation of plants for transplanting to aerohydroponic systems in order to produce mini-tubers, the following modified nutrient media are optimal options: with a reduced number of mineral components (1/2 and 1/3) and with a reduced content of agar-agar.

Experimental and Numerical Investigations on High Performance SFRC: Cyclic Tensile Loading and Fatigue

In the present study, the capability of high-strength short steel fibers to control the degradation in high-performance concrete was experimentally examined and numerically simulated. To this end, notched prismatic high-performance concrete specimens with (HPSFRC) and without (HPC) short steel fibers were subjected to static and cyclic tensile tests up to 100,000 cycles. The cyclic tests showed that the rate of strain increase was lower for HPSFRC specimens and that the strain stagnated after around 10,000 cycles, which was not the case with HPC specimens. The microscopic examinations showed that in HPSFRC, a larger number of microcracks developed, but they had a smaller total surface area than the microcracks in the HPC. To further investigate the influence of fibers on the behavior of HPSFRC in the cracked state, displacement-controlled crack opening tests, as well as numerical simulations thereof, were carried out. Experiments have shown, and the numerical simulations have confirmed, that the inclusion of short steel fibers did not significantly affect the ultimate strength; however, it notably increased the post-cracking ductility of the material. Finally, the unloading/reloading behavior was examined, and it was observed that the unloading stiffness was stable even for significant crack openings; however, the hysteresis loops due to unloading/reloading were very small.

Carbon storage estimation in a secondary tropical forest at CIEE Sustainability Center, Monteverde, Costa Rica

Secondary growth tropical rainforests have the potential to sequester large amounts of atmospheric carbon dioxide and as such are an important carbon sink. To evaluate a local forest, a Carbon Neutrality Program was initiated at the Council on International Educational Exchange, San Luis Campus, Monteverde, Costa Rica. The study was conducted on 50 hectares of forest classified as Premontane Wet Forest. The forest, part of the Arenal-Monteverde Protected Zone, is estimated to be aproximately 50 years old and is in the upper regions of the San Luis valley at 1100 m elevation. Assessment of the carbon stock in trees was carried out in two permanent, 1 hectare plots, 100 m by 100 m, Camino Real and Zapote. The plots were divided into 25 subplots, 20 m by 20 m totaling 400 m2 per subplot. Ten subplots in each area were studied which represented 1.6% the total surface area of the forest. All of the trees were measured within the subplots that had a diameter at breast height ≥ 10 cm and the height of 10% of the trees measured. The estimated total CO2 sequestered by the campus forest was 18,210 ton (in 2019).

Treatment of difficult-to-treat-dermatophytosis: results of a randomized, double-blind, placebo-controlled study

Introduction: Difficult-to-treat dermatophytosis is an emerging public health problem in Sri Lanka. Safe, effective and affordable treatment is needed to solve this problem. Therefore this study has assessed the effectiveness and safety of modified Whitfield ointment applied twice daily with oral griseofulvin 500 mg daily given over 8 weeks in patients with difficult-to-treat dermatophytosis. Methodology: A randomized, double-blind, within-patient-placebo-controlled trial was conducted in patients with clinico- mycologically (history, physical examination, direct light microscopy examination of scales in potassium hydroxide mount) confirmed difficult-to-treat dermatophytosis. Lesions were randomized to receive modified Whitfield ointment (5% benzoic acid and 5% salicylic acid) or emulsifying ointment. All patients were given oral griseofulvin 500mg once daily. The outcome measures were clinical assessment of disease severity, the total surface area of the lesions and the patient’s perception of the disease severity at baseline and every two weeks up to a maximum of 8 weeks. Results: Thirty patients completed the study. At two weeks, there was a statistically significant improvement in modified Whitfield ointment arm in the clinical assessment of disease severity and the patients' perception. There was a 7.59% reduction in the surface area of lesions in modified Whitfield ointment arm and a 5.83% increase in the surface area of lesions in the emulsifying ointment arm at two weeks. The difference between the two arms in surface area changes was not statistically significant (p = 0.107, df = 29). Conclusions: A combination of modified Whitfield ointment with griseofulvin is significantly effective, safe and affordable option for treating difficult-to-treat dermatophytosis in the tropics.

Expected Values of Some Molecular Descriptors in Random Cyclooctane Chains

The modified second Zagreb index, symmetric difference index, inverse symmetric index, and augmented Zagreb index are among the molecular descriptors which have good correlations with some physicochemical properties (such as formation heat, total surface area, etc.) of chemical compounds. By a random cyclooctane chain, we mean a molecular graph of a saturated hydrocarbon containing at least two rings such that all rings are cyclooctane, every ring is joint with at most two other rings through a single bond, and exactly two rings are joint with one other ring. In this article, our main purpose is to determine the expected values of the aforementioned molecular descriptors of random cyclooctane chains explicitly. We also make comparisons in the form of explicit formulae and numerical tables consisting of the expected values of the considered descriptors of random cyclooctane chains. Moreover, we outline the graphical profiles of these comparisons among the mentioned descriptors.

Silicone Oil Adhesion to Hydrophobic Acrylic Intraocular Lenses: A Comparative Laboratory Study of a New versus an Established Hydrophobic Acrylic Intraocular Lens Material

Background. In vitro assessment of silicone oil adhesion to a new hydrophobic acrylic intraocular lens (IOL) material, the Clareon model CNA0T0, compared with the established AcrySof model SN60WF was carried out. Methods. Silicone oil adhesion was assessed for two types of IOLs, Clareon CNA0T0 (n = 10) and AcrySof SN60WF (n = 10). Lenses were immersed in an aqueous sodium chloride solution for 12 hours and then incubated at room temperature in silicone oil for 12 hours. The lenses were washed with distilled water and photographed at 25x magnification using a microscope. The percent coverage was calculated by dividing the area of oil coverage by the total surface area of the lens. Results. Silicone oil adhesion to the surface of the CNA0T0 lens ranged from 4% to 22%, with a mean ± SD coverage of 8% ± 4%. Silicone oil adhesion to the surface of the SN60WF lens ranged from 1% to 17%, with a mean coverage of 9% ± 4%. The silicone oil adhesion of CNA0T0 was equivalent to that of SN60WF ( P > 0.05 ). Conclusions. The new Clareon model CNA0T0 IOL has silicone oil adhesion and interaction that are equivalent to the established AcrySof IOL.

Modification of bentonite clay & its applications: a review

Bentonite clay is one of the oldest clays that humankind has been using from ancient times as traditional habits and remedies. In recent years researchers have found many applications of bentonite clay due to its various physio-chemical properties. In the present work, various physical and chemical properties of bentonite such as surface area, adsorption, swelling properties, cation exchange properties, etc. have been studied. This study also includes various procedures of modification of bentonite clay into Chitosan/Ag-bentonite composite, Fe-Modified bentonite, Hydroxyl-Fe-pillared-bentonite, Organo Bentonite, Organophilic clay, Arenesulfonic Acid-Functionalized Bentonite, Bentonite clay modified with Nb2O5. The study reveals that bentonite clay has large surface area due to similar structure with montmorillonite and it is found that the functionality of bentonite can be increased by increasing total surface area of the clay. Due to high cation exchangeability of bentonite, various cations can be incorporated into it. After purification and modification, the absorbent aluminum phyllosilicate bentonite clay can be used as an efficient catalyst in various types of catalytic reactions. Moreover, bentonite clay can be applied in various field like drilling, civil engineering, agriculture and water treatment.

Sharp Bounds of First Zagreb Coindex for F -Sum Graphs

Let G = V E , E G be a connected graph with vertex set V G and edge set E G . For a graph G, the graphs S(G), R(G), Q(G), and T(G) are obtained by applying the four subdivisions related operations S, R, Q, and T, respectively. Further, for two connected graphs G 1 and G 2 , G 1 + F G 2 are F -sum graphs which are constructed with the help of Cartesian product of F G 1 and G 2 , where F ∈ S , R , Q , T . In this paper, we compute the lower and upper bounds for the first Zagreb coindex of these F -sum (S-sum, R-sum, Q-sum, and T-sum) graphs in the form of the first Zagreb indices and coincides of their basic graphs. At the end, we use linear regression modeling to find the best correlation among the obtained results for the thirteen physicochemical properties of the molecular structures such as boiling point, density, heat capacity at constant pressure, entropy, heat capacity at constant time, enthalpy of vaporization, acentric factor, standard enthalpy of vaporization, enthalpy of formation, octanol-water partition coefficient, standard enthalpy of formation, total surface area, and molar volume.

Numerical Prediction of Homogeneity of Gas Flow through Perforated Plates

Vanes and baffles are often used as flow distributors where uniform flow is required in the apparatus of large cross-section surface areas. As an alternative, perforated plates with a range of open area ratios are applied to produce required gas flow homogeneity. Usually, the plates with various open area ratios are combined into large panels, of which total surface area can reach hundreds of square meters for large-sized industrial apparatus. Numerical modelling of the flow through such panels can be thought of as overly complex, time-consuming, and inefficient due to numerous small open area ratios in the plates and large differences in dimensions between open area ratios and free-stream areas. For this reason, numerical models of gas flow are limited to single plates only with constant open area ratios. A new indirect modelling approach of gas flow through the perforated plates panel with structural elements and various open area ratios with application of the porous media model is proposed. A perforated plate was experimentally investigated in terms of pressure drop and velocity distribution. The data obtained were used for the validation of the numerical results, which differed from the experimental results by less than 5%. In the next step, numerical analyses were performed for plates with open area ratios in the range of 30 to 70% for gas velocities of 5 and 10 m/s. A general correlation for pressure drop as a function of open area ratio was proposed. Finally, systematic numerical studies of the flow through both perforated and porous plates including structural elements were performed. The internal resistance of the porous core was calculated by means of a developed correlation. A good agreement between results with an error lower than 15% was observed.

Investigating the Inhibitive Characteristics of Moringa Oleifera on the Corrosion of Mild Steel

This work deals with the inhibitive characteristics of Moringa oleifera fruits and leaves extracts in Hydrochloric Acid solution and Sodium Hydroxide solution respectively on the corrosion of mild steel. This was carried out using weight loss and polarization techniques. The effects of immersion time, the effect of acid and alkaline concentration on the corrosion behavior of mild steel in 1.0M HCl and 1.0 NaOH with addiction of extracts were deduced. The fruits which were dried and grounded to powder of 10g and the leaves which range from 25cm3 to 100cm3 were used for this study. The corrosion rate was very high in the absence of inhibitors (Moringa oleifera fruits and the leaves extracts). The mild steel was cut into coupon averaging a total surface area of 4.262cm2 . The sample was weighed and immersed into a beaker containing 1.0M NaOH with different volumes of moringa leaves and 1.0M HCl with 10g dried concentrated powdered moringa fruits with coupons removed every 7 days for weight loss measurements till 4 weeks. The corrosion rates were found to be decreased by 83% in 1.0M HCl and 78% in 1.0M NaOH respectively, values of inhibition efficiency (ࣁ (%were calculated from weight loss. The results obtained showed that the Moringa oleifera fruits and leaves extracts could serve as effective inhibitors on the corrosion of mild steel in HCl and NaOH respectively. Keywords: Moringa oleifera, Corrosion rate, Weight loss, Mild steel, Inhibitor.