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Open access

Vincenzo Alagna, Vincenzo Bagarello, Simone Di Prima, Fabio Guaitoli, Massimo Iovino, Saskia Keesstra and Artemi Cerdà

Abstract

In bare soils of semi-arid areas, surface crusting is a rather common phenomenon due to the impact of raindrops. Water infiltration measurements under ponding conditions are becoming largely applied techniques for an approximate characterization of crusted soils. In this study, the impact of crusting on soil hydraulic conductivity was assessed in a Mediterranean vineyard (western Sicily, Italy) under conventional tillage. The BEST (Beerkan Estimation of Soil Transfer parameters) algorithm was applied to the infiltration data to obtain the hydraulic conductivity of crusted and uncrusted soils. Soil hydraulic conductivity was found to vary during the year and also spatially (i.e., rows vs. inter-rows) due to crusting, tillage and vegetation cover. A 55 mm rainfall event resulted in a decrease of the saturated soil hydraulic conductivity, Ks, by a factor of 1.6 in the inter-row areas, due to the formation of a crusted layer at the surface. The same rainfall event did not determine a Ks reduction in the row areas (i.e., Ks decreased by a non-significant factor of 1.05) because the vegetation cover intercepted the raindrops and therefore prevented alteration of the soil surface. The developed ring insertion methodology on crusted soil, implying pre-moistening through the periphery of the sampled surface, together with the very small insertion depth of the ring (0.01 m), prevented visible fractures. Consequently, Beerkan tests carried out along and between the vine-rows and data analysis by the BEST algorithm allowed to assess crusting-dependent reductions in hydraulic conductivity with extemporaneous measurements alone. The reliability of the tested technique was also confirmed by the results of the numerical simulation of the infiltration process in a crusted soil. Testing the Beerkan infiltration run in other crusted soils and establishing comparisons with other experimental methodologies appear advisable to increase confidence on the reliability of the method that seems suitable for simple characterization of crusted soils.

Open access

Othman A. Al Hanbali, Haji Muhammad Shoaib Khan, Muhammad Sarfraz, Mosab Arafat, Shakeel Ijaz and Abdul Hameed

Abstract

Use of transdermal patches can evade many issues associated with oral drug delivery, such as first-pass hepatic metabolism, enzymatic digestion attack, drug hydrolysis and degradation in acidic media, drug fluctuations, and gastrointestinal irritation. This article reviews various transdermal patches available in the market, types, structural components, polymer role, and the required assessment tools. Although transdermal patches have medical applications for smoking cessation, pain relief, osteoporosis, contraception, motion sickness, angina pectoris, and cardiac disorders, advances in formulation development are ongoing to make transdermal patches capable of delivering more challenging drugs. Transdermal patches can be tailored and developed according to the physicochemical properties of active and inactive components, and applicability for long-term use. Therefore, a number of chemical approaches and physical techniques for transdermal patch development are under investigation.

Open access

Mohammed Albratty, Karam Ahmed El-Sharkawy and Hassan Ahmed Alhazmi

Abstract

In an attempt to produce heterocyclic compounds based on 1,3,4-oxadiazole derivatives with potential antiviral activity, synthesis of compound 1 [2-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)acetonitrile] was performed through the reaction of cyanoacetic acid hydrazide with carbon disulfide in alcoholic potassium hydroxide. Compound 1 has an activating methylene group, so it was directed toward some specific reactions. Thus, aryldiazonium chlorides reacted with compound 1 affording hydrazono derivatives 2a-c. Also, aromatic aldehydes reacted with compound 1 to produce compounds 3a,b. Furthermore, cyclic ketones were subjected to the synthesis of fused thiophene derivatives 4a,b via reaction with compound 1 in the presence of elemental sulfur. In addition, 1,3,4-oxadiazole derivative 1, when reacted with isothiocyanates, salicylaldehyde or 1,3-dicarbonyl compounds, formed thiazole derivatives 5a,b, coumarin derivative 6 and alkenyl derivatives 7a,b resp. Compound 7b underwent cyclization to afford pyridine derivative 8. Arylhydrazono derivatives 9a,b were produced through the reaction of compound 7a with aryldiazonium chlorides. Products 9a,b underwent cyclization to produce pyridazine derivatives 10a,b. Finally, 1,3,4-oxadiazole derivative 1 was directed toward reaction with hydrazine derivatives, bromoacetophenone and ethylchloroacetate affording compounds 11a,b, 12 and 13, resp. Fused thiophene derivatives 14a,b were produced via reaction of compounds 4a,b with a mixture of malononitrile and ethylorthoformate. Antiviral activity of the synthesized products showed that 5-(4-amino-3-ethyl-2-thioxo-2,3-dihydrothiazol-5-yl)-1,3,4-oxadiazole-2(3H)-thione (5a) and 5-(4-amino-3-phenyl-2-thioxo-2,3-dihydrothiazol-5-yl)-1,3,4-oxadiazole-2(3H)-thione (5b) acted as the most active agents against Feline herpes virus, Feline corona virus, Herpes simplex virus-1 and Herpes simplex virus-2, whereas compound 2-(5-(2-phenylhydrazono)-4,5-dihydro-1,3,4-oxadiazol-2-yl)acetonitrile (11b) was the most effective against Vaccinia virus, Herpes simplex virus (TK-KOS-ACVr), Coxsackie virus B4 and Vesicular stomatitis virus.

Open access

Maja Beus, Diana Fontinha, Jana Held, Zrinka Rajić, Miguel Prudêncio and Branka Zorc

Abstract

The paper is focused on the synthesis and screening of the antiplasmodial activity of novel fumardiamides 5–10 with the mefloquine pharmacophore and a Michael acceptor motif. Multi-step reactions leading to the title compounds included two amide bond formations. The first amide bond was achieved by the reaction of (E)-ethyl 4-chloro-4-oxobut-2-enoate (1) and N 1-(2,8-bis(trifluoromethyl)quinolin-4-yl) butane-1,4-diamine (2). The obtained ester 3 was hydrolyzed and gave acid 4, which then reacted with the selected halogenanilines in the presence of HATU/DIEA and formed products 5–10. Title compounds showed marked, dose dependent activity in vitro against hepatic stages of Plasmodium berghei. IC 50 values of the most active compounds 5, 7 and 9 bearing 3-fluoro, 3-chloro and 3-trifluoromethyl substituents were 3.04–4.16 µmol L−1, respectively. On the other hand, the compounds exerted only weak activity against the erythrocytic stages of two P. falciparum strains (Pf3D7 and PfDd2) in vitro, with the exception of compound 5 (IC 50 = 2.9 µmol L−1).

Open access

Monika Śleziak and Marek Duliński

Abstract

The isotope activity concentration of rocks and bottom sediments was evaluated based on the samples collected from sedimentation ponds and gangue repositories. Radium 226Ra, thorium 228Th and potassium 40K activities were measured by gamma spectrometry using high-purity germanium detector – HPGe 4020. The radiation effect resulting from the presence of natural radionuclides was estimated by radiological hazard indices such as f 1 and f 2 coefficients, radium equivalent, internal and external hazard indices and absorbed dose rate. Performed measurements and calculations have shown that the bottom sediments are most contaminated. They may pose a serious radiological hazard for present and future generations.

Open access

Amir Ali, Muhammad Makshoof Athar, Mahmood Ahmed, Kashif Nadeem, Ghulam Murtaza, Umar Farooq and Muhammad Salman

Abstract

With the increased number of multi-drug formulations, there is a need to develop new methods for simultaneous determinations of drugs. A precise, accurate and reliable liquid chromatographic method was developed for simultaneous determination of paracetamol, thiamine, and pyridoxal phosphate in pharmaceutical formulations. Separation of analytes was carried out with an Agilent Poroshell C18 column. A mixture of ammonium phosphate buffer (pH = 3.0), acetonitrile and methanol in the ratio of 86:7:7 (V/V/V) was used as the mobile phase pumped at a flow rate of 1.8 mL min−1. Detection of all three components, impurities and degradation products was performed at the selected wavelength of 270 nm. The developed method was validated in terms of linearity, specificity, precision, accuracy, LOD and LOQ as per ICH guidelines. Linearity of the developed method was found in the range 17.5–30 µg mL−1 for thiamine, 35–60 µg mL−1 for pyridoxal phosphate and 87.5–150 µg mL−1 for paracetamol. The coefficient of determination was ≥ 0.9981 for all three analytes. The proposed HPLC method was found to be simple and reliable for the routine simultaneous analysis of paracetamol, thiamine and pyridoxal phosphate in tablet formulations. Complete separation of analytes in the presence of degradation products indicated selectivity of the method.

Open access

Andrej Martinčič, Tone Wraber and Igor Dakskobler

Abstract

In the alpine belt of the Julian Alps (glacial cirque Na Jezerih under Mt. Veliki Rokav, Jarečica, the Mangart Saddle and Prodi under Mt. Mangart as well as Mt. Plešivec in the rock wall of Loška Stena) we studied the phytosociology and ecology of snow-bed vegetation with dominating flowering plants Salix herbacea, Luzula alpinopilosa, Gnaphalium supinum, Soldanella pusilla and Salix retusa, and numerous moss species. Based on the comparison with similar snow-bed communities in the Central, Eastern and Southern Alps we described a new association Salicetum retuso-herbaceae and classified it into the alliance Salicion herbaceae and class Salicetea herbaceae. We determined several successional stages of snow-bed vegetation on mixed calcareous-silicate bedrock that we treat as variants, in two relevés also the initial association Polytrichetum sexangularis.

Open access

Sergio X. Lima, Karolina P. S. Costa, Zelmo R. Lima, Fagner C. Rother, Olga M. O. Araujo, Helio C. Vital, Tercio Brum, Wilson F. R. S. Junior, Jose Carlos C. Amorim, Matthew J. F. Healy and Edson R. Andrade

Abstract

The detonation of an (hypothetical) improvised nuclear device (IND) can generate atmospheric release of radioactive material in the form of particles and dust that ultimately contaminate the soil. In this study, the detonation of an IND in an urban area was simulated, and its effects on humans were determined. The risk of solid cancer development due to radiation was calculated by taking into account prompt radiation and whole-body exposure of individuals near the detonation site up to 10 km. The excess relative risk (ERR) of developing solid cancer was evaluated by using the mathematical relationships from the Radiation Effects Research Foundation (RERF) studies and those from the HotSpot code. The methodology consists of using output data obtained from simulations performed with the HotSpot health physics code plugging in such numbers into a specific given equation used by RERF to evaluate the resulting impact. Such a preliminary procedure is expected to facilitate the decision-making process significantly.

Open access

K. Szmuc, M. Kus-Liskiewicz, Ł. Szyller, D. Szmuc, M. Stompor, I. Zawlik, T. Ruman, S. Wołowiec and J. Cebulski

Abstract

The composite containing nanosilver uniformly deposited on matrix composed of CaHPO4 x 2H2O (brushite, ca 89 mass %), CaHPO4 (monteonite, ca 9.5 mass%), and Ag3PO4 (0.5 mas%) was obtained by addition of calcium nitrate and silver nitrate aqueous solution at 30:1 Ca:Ag molar ratio into excess of (NH4)2PO4 solution at pH 5.0 – 5.5. The isolated solid was characterized by STEM, XRD, and LDI mass spectrometry. It has been found that nanosilver was uniformly distributed within composite as <10 nm diameter sized nanoparticles. Determination of silver by AAS showed that 60% of silver is present as Ag(0) nanoparticles, the present as matrix Ag3PO4 as identified by XRD method. The composite showed strong growth inhibition in E. coli and P. aeruginosa strains, and moderate towards S. aureus. The C. albicans cells were the most resistant to the tested material, although still composite was moderately cytostatic for the yeast.

Open access

Nathalia Yeremenko

Abstract

The present paper studies the ruderal vegetation of the class of Robinietea in Kryvyi Rih. We present the spontaneous woody vegetation of parks and other artificial plantations. Urban landscapes remain unstudied phytosociologically despite the highly diverse habitat niches. We have carried out the comparisons of communities from other regions of Ukraine and adjacent territories. In total, four associations and one derivate community, belonging to three alliances, were identified and categorized as follows: Chelidonio-Acerion negundi (synanthropic tree communities with Acer negundo), Chelidonio majoris-Robinion pseudoacaciae (artificial and spontaneous plantations of Robinia pseudoacacia), Geo-Acerion platanoidis (artificial plantations of broad-leaved tree species). The ordination analysis indicates ecological differentiation of syntaxa investigated in Kryvyi Rih. The most important of them are soil aeration (Ae), the cryo-climate (Cr) and nitrogen content in soil (Nt). Critical revision of the class Robinietea syntaxonomy demands further current research.