42 research outputs found
Facies analysis and paleoenvironmental reconstruction of Upper Cretaceous sequences in the eastern Para-Tethys Basin, NW Iran
Upper Cretaceous mixed carbonate-siliciclastic sequences are among the most important targets for hydrocarbon exploration in the Moghan area, located in the eastern Para-Tethys Basin. Despite of their significance, little is known about their facies characteristics and depositional environments. Detailed facies analysis and paleoenvironmental reconstruction of these sequences have been carried out in eight surface sections. Accordingly, four siliciclastic facies, eight carbonate facies and one volcanic facies have been recognized. Detailed facies descriptions and interpretations, together with the results of facies frequency analysis, standard facies models and Upper Cretaceous depositional models of Para-Tethys Basin, have been integrated and a non-rimmed carbonate platform is presented. This platform was affected by siliciclastic influx, in the form of coastal fan delta and submarine fans in the shallow- to deep-marine parts, respectively. This model is interpreted to be shallower in the central and northeastern parts of the Moghan area. Toward the southeast and southwest, this shallow platform turns into deep marine settings along steep slopes without remarkable marginal barriers
Introducing a sustainable soil fertility system for chickpea (Cicer arietinum L.)
In order to introduce a sustainable soil fertility system for chickpea, field experiments were carried out in 2007 and 2008 growing seasons. Experiments were arranged in split-split plot arrangements with three replications. Main plots consisted of (G1): establishing a mixed vegetation of vetch and barley, (G2): without green manure. Also, five strategies for obtaining the base fertilizer requirement including (N1): farm manure; (N2): compost; (N3): triple super phosphate; (N4): farm manure + compost and (N5): farm manure + compost + triple super phosphate. Four levels of biofertilizers consisted of (B1): Phosphate solubilizing bacteria; (B2): Trichoderma harzianum; (B3): Phosphate solubilizing bacteria + T. harzianum; and (B4): without biofertilizers were arranged in sub-sub plots. Results showed that green manure increased pod number and number of fertile pods per plant. Integrating biofertilizers (B3) and green manure (G1) produced the highest pod number per plant and grain yield. The highest amounts of yield and yield components were obtained in G1N5 treatment. Comparison of 3-way interactions showed that G1N5B3 was the best treatment. Significant increase of N, P, K, Fe and Mg content in leaves and grains emphasized on superiority of mentioned treatment because each one of these nutrients has an approved role in chlorophyll synthesis and photosynthesis ability of the crop. The N5 treatment in addition to having the highest yield had the best grain quality due to high protein, starch and total sugar contents, low crude fiber and reduced cooking time.Key words: Biofertilizer, chickpea, compost, farm manure, soil fertility system
Investigation of the role of exogenous use of sucrose as an osmoprotectant in increasing Azolla filiculoides resistance to air high temperature and salt stress
Influence of 2.75 to 11 moles sucrose as an exogenous osmoprotectant on salt stressed (7.8-9.1 and 18.2 ms/cm) and temperature stressed (42.36°C) Azolla (A. filiculoides Lam.) was studied. Results showed that enriching salt stressed (9.1 ms/cm) Azolla by 5.5 moles sucrose significantly increased survival percent (S%) and freshness percent (F%), in comparison with control treatment in which no sucrose was used. Enriching Azolla media by 2.75, 5.5 and 8.25 moles sucrose in optimum growth condition (24.18C and 0.65 mS/cm), had no significant effects on growth doubling time (D.T), S% and F% in comparison with control. Enriching Azolla media by 11 moles sucrose in optimum growth condition decreased significantly the S% and F%, in comparison with control plots. Enriching Azolla media by 5.5 moles sucrose, in all salinity levels (0.65, 7.8, 9.1 and 18.25 ms/cm), and air temperatures (24.18 and 42.36C), non-increased S% and F% but not significantly and decreased D.T.A positive correlation was observed between high air temperature and medium salinity in Azolla growth
Investigation of biofilm formation among methicillin-resistant Staphylococcus aureus isolated from children
Background: The aim of the present study was to investigate biofilm formation among Methicillin-resistant Staphylococcus aureus (MRSA) isolated from children referring to a pediatric hospital in Tehran. Methods: In total, 98 MRSA isolates were collected from children referring to a pediatric hospital during 2014 - 2015. All the isolates were confirmed to be MRSA using PCR amplification of the mecA gene. The antibiotic susceptibility patterns of the isolates were determined using the Kirby-Bauer disk-diffusion and E-test methods. In order to assess the ability of biofilm formation among the isolates, Congo red agar (CRA) and Microtiter Plate (Mtp) methods were used. Results: All the isolates were found to be susceptible to linezolid and vancomycin and, likewise, the majority was susceptible to minocycline and rifampicin. CRA and Mtp methods showed that 81.6 and 63.3 of the MRSA isolates, respectively, were biofilm producers. Conclusions: The early identification of S. aureus and detection of biofilm formation by the Mtp method are essential steps towards the prevention of the most serious nosocomial infections. © 2017, Archives of Pediatric Infectious Diseases
Investigation of biofilm formation among methicillin-resistant Staphylococcus aureus isolated from children
Background: The aim of the present study was to investigate biofilm formation among Methicillin-resistant Staphylococcus aureus (MRSA) isolated from children referring to a pediatric hospital in Tehran. Methods: In total, 98 MRSA isolates were collected from children referring to a pediatric hospital during 2014 - 2015. All the isolates were confirmed to be MRSA using PCR amplification of the mecA gene. The antibiotic susceptibility patterns of the isolates were determined using the Kirby-Bauer disk-diffusion and E-test methods. In order to assess the ability of biofilm formation among the isolates, Congo red agar (CRA) and Microtiter Plate (Mtp) methods were used. Results: All the isolates were found to be susceptible to linezolid and vancomycin and, likewise, the majority was susceptible to minocycline and rifampicin. CRA and Mtp methods showed that 81.6 and 63.3 of the MRSA isolates, respectively, were biofilm producers. Conclusions: The early identification of S. aureus and detection of biofilm formation by the Mtp method are essential steps towards the prevention of the most serious nosocomial infections. © 2017, Archives of Pediatric Infectious Diseases
Antibiotic resistance, biofilm formation, and biofilm-associated genes among Stenotrophomonas maltophilia clinical isolates
Objective: The purpose of the present study was to investigate the antimicrobial susceptibility pattern, biofilm production, and the presence of biofilm genes among the S. maltophilia clinical isolates. A total of 85 clinical isolates of S. maltophilia were collected from patients referred to several hospitals. Susceptibility to antibiotics was investigated by disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). By the crystal violet staining method, the capability of biofilm formation was examined. The genes associated with biofilm production were investigated by the PCR-sequencing techniques. Results: All isolates were resistant to doripenem, imipenem, and meropenem. Minocycline, trimethoprim/sulfamethoxazole and levofloxacin exhibited the highest susceptibility of 100, 97.65, and 95.29, respectively. The results of crystal violet staining assay showed that all isolates (100) form biofilm. Moreover, 24 (28.23), 32 (37.65), and 29 (34.12) of isolates were categorized as weak, moderate, and strong biofilm producers, respectively. Biofilm genes including rpfF, spgM and rmlA had an overall prevalence of 89.41 (76/85), 100 (85/85) and 84.71 (72/85), respectively. Rational prescribing of antibiotics and implementation of infection control protocols are necessary to prevent further infection and development of antimicrobial resistance. Combination strategies based on the appropriate antibiotics along with anti-biofilm agents can also be selected to eliminate biofilm-associated infections. © 2021, The Author(s)
Toxin production and drug resistance profiles of pediatric methicillinresistant Staphylococcus aureus isolates in Tehran
Role of clover species and AM Fungi (Glomus mosseae) on forage yield, nutrients uptake, nitrogenase activity and soil microbial biomass
. Role of clover species and AM Fungi (Glomus mosseae) on forage yield, nutrients uptake, nitrogenase activity and soil microbial biomass. Journal of Agricultural Technology 5(2): 337-347. The effects of earthworms (Ew), arbuscular mycorrhizal (AM) fungi and mixed cropping systems on nitrogenase activity of rhizosphere free-living bacteria, soil microbial biomass C (MBC) and growth of clovers were studied in various mixed cropping ratios of 1:0, 3:1, 1:1 and 1:3 berseem clover (Trifolium alexandrinum L.) to Persian clover (Trifolium resupinatum L.). AMF G. mosseae and cropping system gave significantly affected on total forage yield. Mixed cropping gave a greater stability of yield over monoculture. Although G. mosseae application increased mycorrhiza colonization rate but there was no obvious effect of clover ratios on mycorrhiza colonization rate. The greatest P-uptake was in the berseem clover:Persian clover ration treatment of 3:1. N-uptake accumulated in above-ground biomass of 173.64 kg ha -1 obtained from mixed cropping BP (3:1) with the presence of G. mosseae. AM fungi G. mosseae increased microbial biomass from 260.2 to 459.2 mg C kg -1 . The greatest amounts of 404 mg kg -1 soil microbial biomass C was found in the 1:1 ratio of berseem clover to Persian clover. With AM G. mosseae inoculation, the greatest nitrogenase activity of rhizosphere free-living bacteria was a 1:1 ratio of berseem clover to Persian clover
Hydrogen Peroxide as a Green Oxidant for the Selective Catalytic Oxidation of Benzylic and Heterocyclic Alcohols in Different Media: An Overview
Among a plethora of known and established oxidant in organic chemistry, hydrogen peroxide stands in a special position. It is commercially and inexpensively available, highly effective, selective, and more importantly it is compatible with current environmental concerns, dictated by principles of green chemistry. Several chemicals or their intermediates that are important in our daily life such as pharmaceuticals, flavors, fragrances, etc. are products of oxidation of alcohols. In this review, we introduce hydrogen peroxide as an effective, selective, green and privileged oxidant for the catalyzed oxidation of primary and secondary benzylic and heterocyclic alcohols to corresponding carbonyl compounds in different media such as aqueous media, under solvent-free conditions, various organic solvent, and dual-phase system
Facies analysis and paleoenvironmental reconstruction of Upper Cretaceous sequences in the eastern Para-Tethys Basin, NW Iran
Upper Cretaceous mixed carbonate-siliciclastic sequences are among the most important targets for hydrocarbon exploration in the Moghan area, located in the eastern Para-Tethys Basin. Despite of their significance, little is known about their facies characteristics and depositional environments. Detailed facies analysis and paleoenvironmental reconstruction of these sequences have been carried out in eight surface sections. Accordingly, four siliciclastic facies, eight carbonate facies and one volcanic facies have been recognized. Detailed facies descriptions and interpretations, together with the results of facies frequency analysis, standard facies models and Upper Cretaceous depositional models of Para-Tethys Basin, have been integrated and a non-rimmed carbonate platform is presented. This platform was affected by siliciclastic influx, in the form of coastal fan delta and submarine fans in the shallow- to deep-marine parts, respectively. This model is interpreted to be shallower in the central and northeastern parts of the Moghan area. Toward the southeast and southwest, this shallow platform turns into deep marine settings along steep slopes without remarkable marginal barriers