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Herein, the manganese (Mn) and nickel (Ni) doped cobalt oxide (Co3O4) with stacks spinel structure were incorporated on the polypyrrole (PPy)- coated Fluorine-doped tin oxide (FTO) glasses to improve oxygen evolution reaction (OER) efficiencies in PEC water splitting. We designed such a heterostructure configuration as an ideal model to understand the impact of the. MnCo2O4 and NiCo2O4 on the photoelectrocatalytic performances. Results showed that the FTO/PPy/NiCo2O4 possess superior photocurrent density (11.37 mA cm−2) compared to the FTO/PPy/Co3O4 (7.26 mA cm−2), and FTO/PPy/MnCo2O4 (9.16 mA cm−2) at 1.23 V vs. reverse hydrogen electrode (RHE). Moreover, the electrochemical surface area (ECSA) of the FTO/PPy/NiCo2O4 was obtained 1.4 and 1.8-folds higher than those considered for the FTO/PPy/MnCo2O4 and FTO/PPy/Co3O4, respectively. Specific spinel configuration of NiCo2O4 on PPy films provided the highest ECSA to access the carrier charge and their contribution in the redox reaction. The highest value of the O2 (5.256 μmol. h−1) was exuded from the surface of the FTO/PPy/NiCo2O4 by 2.5 and 1.8 orders of magnitude compared to those estimated for FTO/PPy/Co3O4, FTO/PPy/MnCo2O4.

Thyme (Thymus vulgaris L.) is known to produce a variety of phenolic monoterpenes such as thymol and carvacrol. Thymol and carvacrol are health-promoting, biocide and antitoxin compounds and have been considered as the main constituents of essential oils in T. vulgaris. To improve our understanding of the regulation of monoterpene biosynthesis in thyme, the expression of genes related to thymol and carvacrol biosynthesis in different tissues and in response to abiotic elicitors was analyzed. Methyl jasmonate (MeJA), salicylic acid (SA), trans-cinnamic acid (tCA) and UV-C irradiation were applied to T. vulgare leaves and transcript levels of early (DXR) and late (TvTPS1, CYP71D178 and CYP71D180) biosynthetic genes of thymol and carvacrol were measured. The results showed that early step and late step genes in thymol/carvacrol biosynthesis are differentially regulated. DXR was not found to be exclusively expressed in glandular trichomes; in contrast, biosynthetic genes including γ-terpinene synthase (TvTPS1) and two cytochrome P450s, CYP71D178 and CYP71D180, were preferentially expressed in glandular secretory trichomes. The high expression of late biosynthetic genes in glandular trichomes, which also contain the highest concentration of thymol and carvacrol, suggests that glandular trichomes are the structure in which thymol/carvacrol biosynthesis and accumulation occur. Our results indicate that in addition to abiotic elicitors, developmental and spatial factors also play a key role in the biosynthesis of thymol and carvacrol, most likely relating to glandular trichome density and/or activity. Hence optimization of these factors could be considered as a useful strategy to achieve high yield of valuable compounds in T. vulgare or other closely related plant species.

The present case–control study was conducted to determine the prevalence of Haemobartonella felis, study the role of its risk factors and compare the different diagnostic tests. In order to achieve these goals, direct blood smear and single PCR assay were performed on blood samples from 90 cats (45 healthy controls and 45 sick cats). In addition, age, sex, breed, outdoor access, castration and density of living area were recorded in each group, and haematological analysis was performed on all blood samples. A total of 50 and 72.2 % of cats were H. felis positive in direct blood smear and PCR, respectively. The results showed a significant difference between control and case groups regarding the quantitative variables including fever and dehydration in direct blood smear, and tachycardia, icterus, fever and dehydration in PCR (P

Chemical characteristics of groundwater and the composition of newly formed precipitates are critical in the management of modern irrigated agriculture in arid regions. Water samples representing the main aquifers in Riyadh region, Saudi Arabia, and solid samples fromthe newly formed precipitates were studied. Results showed that water temperature varied between 30.3-69°C, being higher in the deep aquifer and low in the relatively shallow aquifers. Initial water pH ranged from 6.39-7.92, increasing to 7.65-8.20 at atmospheric conditions. Shallowaquifer waters were categorized into sulfate-type and Cl- or no-dominant type waters, while the deep aquifers were characterized as Cl-type and no-dominant type. Soluble H 4 SiO 4 , soluble Fe and Mn ranged from 3.15 to 18.82, 0.10 to 17.30, and 0.01 to 4 0.32 mg L-¹, respectively. Calculation of saturation indices from water composition at initial, closed and equilibriumconditions indicated that changes in pH and water temperature cause major chemical changes in t...

Due to the sandy character of the desert sandy soils, surface reactivity and hence adsorption of micronutrients are very low. Therefore, different fractions from sand particles were coated with four partially hydroxylated ferric sols of OH/Fe molar ratio of 1.00, 1.50, 2.00, and 2.84. The obtained results prove that the extractability of iron is reduced by increasing the OH/Fe molar ratio before its addition to the sand particles. Iron oxide coating of sand particles increased the amount of Cu adsorbed as compared with uncoated ones. With regard to the effect of polymerization degree of ferric sols, results show that decreasing OH/Fe molar ratio of iron sols enhanced the Cu adsorption maximum capacity, as calculated from the Langmuir equation. The amount of adsorbed Cu increased by decreasing the size of sand particles. Moreover, increasing the pH value of Cu equilibrium solution from 4.5 to 7.5 resulted in more adsorption of Cu by ferric hydroxide-coated sand particles.

Zinc solubility in clay and soil suspensions was controlled by chemisorption at pH 4.5 – 7.0. The solubility in clay mineral suspensions was in the order palygorskite < montmorillonite « kaolinite and reflected the high affinity of zinc to palygorskite and the high CEC of montmorillonite. The solubility in soil suspensions was in the order Haplustoll < Torrifluvents and reflected the effect of high CEC and organic matter content of the first. The slopes of the pH-pZn curves, calculated zinc potential and sequential desorption data suggested that Zn++ − Zn(OH)2 aqueous controlled the solubility of zinc in soil and clay mineral suspensions at pH 7.5 – 9.0. The slopes of the pH–pZn curves of two soils were, however, modified by the possible peptization of organic matter and Zn(OH)2.

This research was undertaken to study the pedo-chemical characteristics of selected playas (sabkhahs) in the Arabian Shelf. Results indicated that most of the sabkhahs are flat to almost flat having salt crusts with variable thickness. Profiles representing the sabkhah surface are extremely saline compared with that of the surrounding landscapes. The dominant soluble salts are Cl- and SO4(2-) of Na+ followed by Ca2 + or Mg2+. The compositions of the coastal sabkhahs profile layers are closely related to the Gulf water composition while the inland playas are more associated with local conditions. This was continued from the similarity in salt levels, ion molar ratios and relatively high correlation coefficients between the electrical conductivity of soluble salts (EC) and either soluble B3+ (r2 =0.80) or soluble Mg2 (r2=0.60) in coastal compared with that of the inland sabkhahs (r2=0.17) and (r2 =O.37), respectively. The main pedological process affecting the formation of coastal sabkhahs is the upward movement of the water table which is rich in sales originating from the Gulf waters either directly or through wind action. Leaching, accumulation of sediments and evaporative concentrations of the solutes are the processes prevailing in the inland sabkhahs. Salt crusts are dominated by Cl-and SO4(2-) of Na+ , Mg2+ and Ca2+ salts while K+ salts are relatively low. X-ray diffraction patterns confirm the presence of halite, gypsum and carbonate minerals. Epsomite and bloedtte minerals were identified in both coastal and inland sabkhahs. Specific minerals and relative abundance was quite variable between the salt cmsts due to the characteristic conditions of each sabkhah. The major differences between the inland and coastal sablthahs are related to the source, composition and depth of the water table and consequently the composition and mineralogy of the surface salt crusts.

Summary Qasim, some 500 km north-west of Riyadh, is one of the agriculturally important areas of Saudi Arabia. Silt fractions of the soils of the Wadi ar Rimah and side wadis, classified as Torrifluvents, are characterized by high quartz contents and the universal occurrence of kaolinite and felspar, generally with plagioclase predominant; mica, chlorite and hornblende also generally occur. The clay fractions contain mainly palygorskite and a smectite-mica interstratification with smaller amounts of kaolinite, traces of quartz and occasionally chlorite. Palygorskite generally increases in content with depth. Variations in mineralogy probably reflect changes in depositional conditions rather than pedogenic processes; possible reasons for the high palygorskite content are discussed. Sedentary soils (Torriorthents) reflect the mineralogy of the rock from which they were derived. In clay fractions from salt-marsh soils (Salorthids) calcite reacts strongly with smectite-mica during DTA.

Ten soil profiles from the agricultural areas in Saudi Arabia were investigated for their mineralogical properties and some general characteristics. It was found that the soils of the eastern region were Torrifluvents and Gypsiorthids, coarse in texture with high salt, gypsum and carbonate contents. Soils of the central region were found to be Torriorthents, Torrifluvents and Torripsamments, medium to coarse in texture with smaller amounts of gypsum and salt than soils in the east. Soils of the western region were Haplargids with minor amounts of carbonate and salt. Carbonate, quartz and gypsum were found to be the main constituents of the sand and silt fractions in soils of the eastern region, while quartz, carbonate and feldspars dominated the sand and silt in the central region. The sand and silt fractions of soils in the west contained mainly quartz, feldspars, hornblende and mica. Palygorskite dominated the clay fractions of soils in the east, while kaolinite was found to be dominant in the central region, and kaolinite, smectite and mica in the west. The mineral composition of the soils was affected by the rocks from which they were derived. Igneous and metamorphic rocks of the Arabian Shield affected the soils in the west, while sedimentary rocks had great influence on soils of the central and eastern regions. Mineralbestand ausgewahlter Boden aus Saudi Arabien Zehn Boden landwirtschaftlich genutzter Flachen in Saudi Arabien wurden auf ihre chemischen, physikalischen und mineralogischen Eigenschaften untersucht. Boden der ostlichen Region zeigten hohe Salz-, Gips- und Karbonat-Gehalte; sie waren grobkornig und wurden als Torrifluvents und Gypsiorthids klassifiziert. In der zentralen Region waren die Boden (Torriorthents, Torrifluvents und Torripsamments) mittel- bis grobkornig und enthielten weniger Gips und Salze als die Boden im Osten. Boden der westlichen Region waren Haplargids mit geringen Karbonat- und Salzgehalten. Die Sand- und Schluff-Fraktionen der Boden im Osten enthielten hauptsachlich Karbonate, Quarz und Gips, wahrend in der zentralen Region Quarz, Karbonate und Feldspate gefunden wurden. Quarz, Feldspate, Hornblenden und Glimmer machten die Sand- und Schluff-Fraktionen der Boden in der westlichen Region aus. Die Tonfraktion der Boden im Osten bestand hauptsachlich aus Palygorskit, in der zentralen Region aus Kaolinit und im Westen aus Kaolinit, Smectit und Glimmer. Der Mineralbestand der Boden wurde stark von den Ausgangsgesteinen beeinflust. Die vulkanischen und metamorphen Gesteine des Arabian Shield bestimmten die Boden im Westen, wahrend Sedimentgesteine die Boden der zentralen und ostlichen Regionen bestimmten.

These investigations were conducted to provide basic soil chemical, physical, and mineralogical data for an area of Saudi Arabia that had not been studied and for which greatly increased agricultural development is anticipated. Fourteen soils were collected from two arid interior basin areas of Saudi Arabia. The silt and clay mineralogy was studied using x-ray diffraction, differential thermal analysis, and electron microscopy. Quantitative estimation of clay-sized minerals was based on a combination of chemical and x-ray diffraction techniques. The calcareous soils of the central basins show minimal profile development. Particle-size classes range from sandy-skeletal to fine silty. Soils with shallow water tables are saline with large SAR values. The clay minerals in soils of the basins are primarily inherited. Soils developed in alluvium from mixed igneous rocks have clay fractions in which smectite > mica > kaolinite > chlorite, palygorskite, vermiculite. Soils formed from Permian sedimentary rocks have kaolinitic clay fractions. It is postulated that the central basins do not receive sufficient Si inputs for palygorskite neoformation and it is though that palygorskite is detrital, originating from easternregion Tertiary rocks. The soil clays of the central hasins have greater smectite contents than those of the kaolinitic western highland soils and palygorskite-rich eastern-region soils.

The occurrence of palygorskite in some Tertiary sediments in eastern Saudi Arabia was studied. Mineralogical and chemical analyses were made of samples from two sections several meters thick from the Umm er Radhuma and Dammam Formations of Paleocene and Eocene periods, respectively. Layers of shales were observed within the sections of the dolomitic-calcitic limestone of the Umm er Radhuma Formation and of the dolomitic limestone of the Dammam Formation. After treatment for carbonate removal the shales consisted of more than 95% clay-size particles, most of which were

Summary Sodium carbonate added to nutrient solution in sand culture depressed the growth of tomatoes both by the influence of high pH and HCO3− causing chlorosis and by the effect of Na+. Foliar sprays of iron and manganese removed chlorosis and increased growth but did not remove the effect of Na. In a sandy soil Na2CO3 did not cause chlorosis but Na+ depressed yield. Chelated Fe and Mn in the soil solutions (up to 7.3 × 10−4 M Fe and 2.6 × 10−5 M Mn at pH 9.0) were sufficient to supply the crop needs as shown by a second sand culture experiment where plants were fed with nutrient solution plus extracted soil solution.

Summary In normally productive sandy clay loam soil, nitrification of ammonium sulphate and urea as affected by salinity, was studied. Generally, increasing salinity delayed, suppressed or inhibited nitrification. Urea ammonification was slightly affected by salinity and the process appeared to be chemical rather than biological. NO 2 -N accumulation was positively correlated with the level of salinity, i.e., as salinity increases NO 2 -N increases and persisted for long time. The relative sensitivity of Nitrobacter to salinity was discussed.

Summary Theoretical relationships between pH, CO2 partial pressure and alkalinity (bicarbonate + carbonate concentrations) have been shown to apply to solutions and calcite and soil suspensions. The exchange of Na onto three Ca clays shows that Ca is preferred but with negative free energies of exchange. With decreasing total electrolyte concentration, the preference for Ca increases, so that only when the concentration is above 10-3M will significant amounts of exchangeable Na be found in soils. The preference for Ca is illite > montmorillonite > vermiculite. Dilution of the mixed Na-Ca clay suspensions causes exchange, desorption of Na and. in some cases Ca. This desorbed or ‘alkaline’ Na (and Ca) is replaced by H some of which attacks the clays. The apparent hydrolysis coefficient, KG = H adsorbed (Na)/Na adsorbed (H), varies between 5 and 9 × 105, increases with increase in electrolyte concentration and varies in the order vermiculite > illite > montmorillonite. The concentration of alkaline Na + Ca increases with increasing ESP, and with clay type in the same order as the KG values. The pH calculated from the alkaline Na + Ca, assumed equal to the alkalinity was equal to measured values except for montmorillonite where the calculated values were low. Magnesium release by acid attack of the montmorillonite may explain the differences. Vermiculite rich soils will be most likely to accept exchangeable Na and to hydrolyse and develop alkalinity.

Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S1=3.5, S2=6, S3=8.5, and S4=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W1), 40% (W2) and 20% (W3) of the available water.

Ammonium sulfate and urea were added to three soils of widely different composition. After incubation for 28 days at 20°C, from 13 to 89% of the N from ammonium sulfate, and 8 to 71% of the N as urea were not recovered, and at 40°C, 44 to 95% of the N as ammonium sulfate, and 33 to 81% of the N as urea was not recovered as either ammonium‐N or nitrate‐N. Significantly more N was lost from a soil containing 3% calcium carbonate at pH 8.4 as compared to the two other soils containing 25 and 35% calcium carbonate, which have pH's of 7.7 and 7.5, respectively. An incubation temperature of 40°C appeared quite unfavourable for nitrification.