Reduction of 4-nitrophenol to 4-aminophenol over sonoimmobilized silver/reduced graphene oxide nanocomposites on polyester fabric

The current paper is aimed to compare different arrangement of Ag nanoparticles within silver/reduced graphene oxide (Ag/rGO) nanocomposites on the polyester fabric. rGO sheets cannot be dispersed in the water for long time however, thin layer surfactant-free Ag/rGO nanocomposites were immobilized on the surface of polyester. This leads to attain the preserved array of nanocomposites for a long time. TEM, FESEM/EDX, XRD, XPS, cyclic voltammetry, catalytic activity and electrical resistivity were used to characterize Ag/rGO nanocomposites coated polyester fabric. Interestingly, sonoimmobilization of Ag/GO produced an even coating layer of nanocomposites on the polyester fabric. The prepared fabric can be used as a high active and stable nanocatalyst for reduction of 4-nitrophenol (4-NP) in water at room temperature. The created flexible and light fabric showed low electrical resistance and high catalytic activity, wherein sonoimmobilization of Ag/rGO treated samples indicated highest catalytic activity as 4-NP solution completely reduced to 4- AP with assistance of 2×4 cm2 treated polyester after 25 min. On the other hand, introducing sonoprepared silver nanoparticles among graphene nanosheets led to significant lowering of electrical resistivity from 43 kΩ/square in mechanical stirring methodto 2 kΩ/square using ultrasound.     

Interaction of water and nitrogen on maize grown for silage

Water scarcity and environmental pollution due to excessive nitrogen (N) applications are important environmental concerns. The Varamin region, which is located in the central part of Iran, is one of the locations where farmers apply 250-350 kg N ha⁻¹ for silage maize without any concerns with respect to the available water for irrigation. The objective of this study was to quantify the response of the silage maize (Zea mays L.) to variable irrigation and N fertilizer applications under arid and semi-arid conditions and to determine the optimum amount of N fertilizer as a function of irrigation. The maize Hybrid 704 single-cross was planted on 3 August 2003 and on 25 June 2004. The experimental treatments consisted of three N rates (0, 150, and 200 kg N ha⁻¹) and four levels of irrigation, including two deficit irrigation levels 0.70 SWD (soil water depletion) and 0.85 SWD, a full-irrigation level (1.0 SWD) and an over-irrigation level (1.13 SWD). Twelve treatments were arranged in a strip-plot design in a randomized complete block with three replicates. Gravimetric soil samples were collected in 2003 and a neutron probe was used in 2004 to measure soil water content. Leaf area index, total aboveground biomass (TB), plant height, stem diameter, and leaf, stem, and ear dry weight were measured during the growing seasons and at final harvest. Total aboveground biomass was affected by irrigation (P < 0.0001) during both years and was also affected by N fertilizer in 2003 (P = 0.0001) and 2004 (P < 0.0001). However, there was no irrigation and N fertilizer interaction for both years (P > 0.5). Total aboveground biomass and biomass of the crop components increased as a function of the amount of water and N applied. For each of the irrigation levels, there was an associated optimum amount of N, which increased as the amount of irrigation water that was applied increased. Among the four irrigation levels that were studied, 0.85 SWD was the optimum level of irrigation for the conditions at the experimental site. The results also indicated that an increase in N applications is not a good strategy to compensate for a decrease of TB under drought stress conditions. We concluded that the effect of N fertilizer on TB depends on the availability of water in the soil, and that the amount of N fertilizer applied should be decreased under drought stress conditions. Further research will combine these results with a crop simulation model to help optimize nitrogen and water management for silage maize.     

Soil mapping for land‐use planning in a karst area of N Thailand with due consideration of local knowledge

For the development of sustainable land‐management systems in the highlands of N Thailand, detailed knowledge about soil distribution and soil properties is a prerequisite. Yet to date, there are hardly any detailed soil maps available on a watershed scale. In this study, soil maps on watershed level were evaluated with regard to their suitability for agricultural land‐use planning. In addition to common scientific methods (as underlying the WRB classification), participatory methods were used to exploit local knowledge about soils and to document it in a “Local Soil Map”. Where the WRB classification identified eight soil units, the farmers distinguished only five on the basis of soil color and “hardness”. The “Local Soil Map” shows little resemblance with the detailed, patchy pattern of the WRB‐based soil map. On the contrary, the “Local Soil Map” is fairly similar to the petrographic map suggesting that soil color is directly related to parent material. The farmers' perception about soil fertility and soil suitability for cropping could be confirmed by analytical data. We conclude that integrating local soil knowledge, petrographic information, and knowledge of local cropping practices allows for a rapid compilation of information for land‐evaluation purposes at watershed level. It is the most efficient way to build a base for regional land‐use planning.     

Influence of Plant Growth Promoting Rhizobacteria,Compost, and Biochar of Azolla on Rosemary (Rosmarinus Officinalis L.) Growth and Some Soil Quality Indicators in a Calcareous Soil

In order to study the effect of plant growth promoting rhizobacteria (PGPR), Azolla compost and Azolla biochar on some soil quality indicators and rosemary growth, a greenhouse experiment was conducted in a completely randomized design with six replications. Treatments consisted of T₁ (control), T₂ (1% Azolla compost), T₃ (1% Azolla biochar), T₄ (PGPR (P. fluorescens), T₅ (1% compost + PGPR) and T₆ (1% biochar + PGPR). Rosemary growth parameters and nutrients concentration increased in all treatments compared to control. Treatments increased soil nutrient concentrations, soil microbial respiration (SMR) and microbial biomass C (MBC) but decreased soil metabolic quotient (qCO₂) compared to control treatment. A significant enhancement in rosemary growth occurred due to the improved soil quality as a result of organic fertilizers application, particularly by co-application of P. fluorescens and compost or biochar of Azolla.     

Fingerprinting sediment sources in the outlet reservoir of a hilly cultivated catchment in Tunisia

Purpose

Approximately 74 % of agricultural soils in Tunisia are affected by water erosion, leading to the siltation of numerous human-made reservoirs and therefore a loss of water storage capacity. The objective of this study was to propose a methodology for estimating the relative contributions of gully/channel bank erosion and surface topsoil erosion to the sediment accumulated in small reservoirs.

Materials and methods

We tested an approach based on the sediment fingerprinting technique for sediments collected from a reservoir (which has been in operation since 1994) at the outlet of a catchment (Kamech, 2.63 km²). Sampling concentrated on the soil surface (in both cropland and grassland), gullies and channel banks. A total of 17 sediment cores were collected along a longitudinal transect of the Kamech reservoir to investigate the origin of the sediment throughout the reservoir. Radionuclides (particularly caesium-137, ¹³⁷Cs) and nutrients (total phosphorus, total nitrogen and total organic carbon (TOC)) were analysed as potential tracers.

Results and discussion

The applications of a mixing model with ¹³⁷Cs alone or ¹³⁷Cs and TOC provided very similar results: The dominant source of sediment was surface erosion, which was responsible for 80 % of the total erosion within the Kamech catchment. Additionally, we showed that the analysis of a single composite core provided information on the sediment origin that was consistent with the analysis of all sediment layers in the core. We demonstrated the importance of the core sampling location within the reservoir for obtaining reliable information regarding sediment sources and the dominant erosion processes.

Conclusions

The dominance of surface erosion processes indicates that conservation farming practices are required to mitigate erosion in the agricultural Kamech catchment. Based on the results from 17 sediment cores, guidelines regarding the number and location of sampling cores to be collected for sediment fingerprinting are proposed. We showed that the collection of two cores limited the sediment source apportionment uncertainty due to the core sampling scheme to <10 %.     

Determination of antibiotic resistance pattern and virulence genes in Escherichia coli isolated from bovine with subclinical mastitis in southwest of Iran

The aims of the present study were to investigate the prevalence of some virulence genes and also determine the antimicrobial resistance pattern of E. coli isolated from bovine with subclinical mastitis. The milk of 502 cows was collected from 8 dairy herds in the southwest of Iran. Conventional biochemical tests were used for identification of E. coli at the species level. Antimicrobial susceptibility patterns of E. coli isolates were determined by disc agar diffusion method and polymerase chain reaction (PCR) was used for detection of seven virulence genes including f17A, afaE-8, afaD-8, eaeA, cnf1, cnf2, and iucD. Seventy (13.94%) isolates of E. coli were identified in 502 milk samples. The highest rate of resistance was observed against tetracycline (18.6%), while none of the isolates were resistant to streptomycin. Eight (11.5%) out of 70 E. coli isolates carried at least one of the virulence genes. The afaD-8 was the most prevalent gene detected in 5 (7.1%) isolates. The afaE-8, iucD, and eaeA were detected in 3, 3, and 2 isolates respectively. Low prevalence of virulence factors may be indicating that most of the E. coli isolates originated from the commensal flora of cows and enter to the udders via environment contamination with feces.

     

Potassium Mineral Nutrition Combined with Sustained Deficit Irrigation to Improve Yield and Quality of a Late Season Peach Cultivar (Prunus persica L. cv ‘Chatos’)

ABSTRACT

Fruit quality traits are directly related to agronomic practices such as irrigation and fertilization, especially potassium supply since its effects on quality and water drought resistance. The objective of this study was to evaluate the effect of different combinations of potassium rate and application mode (in soil: 200S and 100S, foliar spray: 100F) with two irrigation regimes (FI: irrigation with 100%ETc and DI: irrigation with 66%ETc) on peach yield and quality parameters. The experiment was performed during two consecutive years. At harvest, only in the second year significant differences between treatments were observed in yield. In fact, potassium foliar spray, even in DI regime, improved yield. The fruit diameter was slightly affected by treatments in the first year. However, in the following season foliar potassium spray even in DI water regime increased fruit size. Concerning the firmness, no significant differences were observed in the first year except for the second year it decreased with DI strategy independently of potassium treatment. The soluble solids content was strongly affected by the treatments. The highest values were observed in 100F+DI treatment with no significant effect on acidity. Vegetative growth was affected only by water regime which DI reduced shoot length.     

An in vitro comparative study of follicle stimulating hormone (FSH) and activin A effects on the maturation of preantral follicle-enclosed oocytes from immature Syrian mice

Objectives: It was aimed to investigate the effects of different doses of follicle stimulating hormone (FSH) and activin A on the growth and maturation of preantral mouse follicles during the in vitro culture. Methods: Preantral follicles (90-100 mum in diameter) were harvested from 6-8 week-old Syrian mice and cultured in TCM199 culture medium for 6 days to see the effect of FSH and Activin A. Activin A concentrations in the range of 10-200 ng/ml were used, while 10, 50, 100, 150 and 200 mIU/ml FSH were used in the experiment. Results: Activin A concentration of 100 ng/ml resulted in a significant increase in follicle diameter (170 mum) with the survival rate of 73% as compared to the control (100 mum and 25%, P<0.05). The number of oocytes matured and the percentage of germinal vesicle breakdown (GVBD) was 61 and 70%, respectively as compared to the control (20 and 29%, P<0.05). Follicle diameter (190 mum) and survival rate (85%) increased significantly in the presence of 100 mIU/ml of FSH as compared to the control (P<0.05). But, the administration of activin A+FSH increased the effect of both factors on follicular diameter (205 mum as compared to 100 mum in control, P<0.01). Follicle survival, oocyte maturation and GVBD rates were 91, 81 and 89%, respectively (P<0.01). Conclusion: These results have suggested that exposure to FSH and activin A before the formation of antral cavity had positive effect on follicle survival and oocyte robustness.     

Sequential fractionation of grape seeds into oils, polyphenols, and procyanidins via a single system employing CO2-based fluids

Pure supercritical CO(2) was used to remove >95% of the oil from the grape seeds. Subcritical CO(2) modified with methanol was used for the extraction of monomeric polyphenols, whereas pure methanol was used for the extraction of polyphenolic dimers/trimers and procyanidins from grape seed. At optimum conditions, 40% methanol-modified CO(2) removed >79% of catechin and epicatechin from the grape seed. This extract was light yellow in color, and no higher molecular weight procyanidins were detected. Extraction of the same sample after removal of the oils and polyphenols, but now under enhanced solvent extraction conditions using methanol as a solvent, provided a dark red solution shown via electrospray ionization HPLC-MS to contain a relatively high concentration of procyanidins. The uniqueness of the study is attested to by the use of CO(2)-based fluids and the employment of a single instrumental extraction system.