179 research outputs found
The effect of drought stress and exogenous abscisic acid on growth, protein content and antioxidative enzyme activity in saffron (Crocus sativus L.)
This study was carried out to investigate the effect of drought and abscisic acid (ABA) on growth, protein content and antioxidative enzyme activity in leaves, roots and corms of Crocus sativus L. A comparative study of sample and control showed that leaf relative water content (RWC), length and number of leaves decreased due to drought and ABA when compared to control. Drought and ABA were effective in increasing root length in comparison to control. Though drought and ABA improved the protein content in corms, leaves and roots, maximum protein content was detected in corms. Drought and ABA increased superoxide dismutase (SOD) and peroxidase (POX) activitiy in roots, leaves and corms when compared to that of the control. The highest SOD activity was observed in the roots, followed by leaves and corms, respectively. Furthermore, highest POX activity was observed in roots.Key words: Drought, ABA-treatment, Crocus sativus, peroxidase, superoxide dismutase
[H2-Cryptand 222]2+(Br3 –)2 as a Tribromide-Type Catalyst for the Trimethylsilylation/Tetrahydropyranylation of Alcohols
A stable organic tribromide, [H2-cryptand 222]2+(Br3–)2 was utilized as an active catalyst for the trimethylsilylation/tetrahydropyranylation of alcohols. The method is general for the preparation of OH-protected aliphatic (acyclic and cyclic), aromatic, primary, secondary and tertiary alcohols.Keywords: [H2-cryptand 222]2+(Br3–)2, trimethylsilylation, tetrahydropyranylation, alcohols, tribromide, TMS-ether, THP-ethe
The Problem of Mixing up of Leishmania Isolates in the Laboratory: Suggestion of ITS1 Gene Sequencing for Verification of Species
Background: Leishmaniasis is endemic in Iran. Different species of Leishmania (L.) parasites are causative agents of this disease. Correct identification of Leishmania species is important for clinical studies,prevention, and control of the diseases. Mix up of Leishmania isolates is possible in the laboratory, so there is need for verification of species for isolates of uncertain identity. Different methods may be used for this purpose including isoenzyme electrophoresis and molecular methods. The isoenzyme lectrophoresis, due to its drawbacks, is feasible only in specialized laboratories while molecular methods may be more feasible. The aim of this research was to study the application of the internal transcribedspacer 1 (ITS1) sequencing method, in comparison to isoenzyme electrophoresis method, for verification of Leishmania species.Methods: Six Leishmania isolates were received from different research institutions in Iran. The species of these isolates were known by donating institution according to their isoenzyme profile. The species of these isolates were re-identified in Pasteur Institute of Iran by PCR amplification of ITS1 followed bysequencing and comparison of these sequences with Leishmania sequences in GenBank. Isoenzyme electrophoresis was performed for confirmation of the results of ITS1.Results: ITS1 sequence showed that some isolates were mixed up or contaminated with Crithidia. Isoenzyme electrophoresis confirmed the results of ITS1 sequences.Conclusion: ITS1 sequencing is relatively more feasible than the traditional isoenzyme electrophoresismethod and is suggested for verification of Leishmania species
Dynamic age-related changes of extracellular field potential of isolated AV-node of rabbit
Introduction: Developmental changes in atrioventricular nodal conduction time and refractoriness have been shown in several studies. Prevalence of atrioventricular nodal reentrant tachycardia (AVNRT) is clearly age-dependent. The purpose of this study was to determine developmental changes of basic and frequency-dependent electrophysiological properties of the atrioventricular node (AV-node) in neonatal and adult rabbits. Methods: In this study, the effects of increasing age on the basic and rate-dependent properties of isolated perfused AV-node were analyzed in neonatal (2-week-old) and adult (12-week-old) New Zealand rabbits. Specific stimulation protocols of recovery, facilitation and fatigue were separately applied in each group (n=7). Unipolar extracellular field potential was recorded by a silver electrode (100 μM). Results: The results showed that the basic nodal properties (ERP, FRP, WBCL and AHmax) were significantly shorter in neonates compared to the adult group. The magnitude of fatigue was also decreased in the neonatal group compared to control (18.9 ±3.3 vs. 11.1 ± 1.2 msec). Time constant of recovery of the adult group was significantly higher than the neonatal group (P<0.05). Conclusion: The results of this study showed that nodal basic and frequency-dependent properties are age-related and different developmental changes of slow and fast pathways are responsible for this behavior and may reveal the grater susceptibility of AVNRT in young adults compared to infants
The Effects of Excess Copper on Antioxidative Enzymes, Lipid Peroxidation, Proline, Chlorophyll, and Concentration of Mn, Fe, and Cu in Astragalus neo-mobayenii
To probe the physiological and biochemical tolerance mechanisms in Astragalus neo-mobayenii Maassoumi, an endemic plant around the Cu-rich areas from the North West of Iran, the effect of different copper concentrations at toxic levels on this plant was investigated. Copper was applied in the form of copper sulfate (CuSO4·5H2O) in four levels (0, 50, 100, and 150 μM). We observed no visible symptoms of Cu toxicity in this plant species. During the exposure of plants to excess copper, the antioxidant defense system helped the plant to protect itself from the damage. With increasing copper concentration, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities increased in leaves and roots () compared with that of the control group. The chlorophyll amount gradually declined with increasing Cu concentrations. However, reduction in the 50 μM level showed insignificant changes. Enhanced accumulation of proline content in the leaves was determined, as well as an increase of MDA content (oxidative damage biomarker) (). The results indicated that Cu contents in leaves and roots enhanced with increasing levels of Cu application. The Fe and Mn contents in both shoots and roots significantly decreased with increasing Cu concentration. Finally, the mechanisms of copper toxicity and copper tolerance in this plant were briefly discussed
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Enhancing smart city operation management: integrating energy systems with a subway synergism hub
This paper is centered on establishing a secure framework for the optimal concurrent operation of a smart city, encompassing transportation, water, heat, electrical, and cooling energy systems. The studied smart city includes the microgrid, smart transportation system (STS), energy hub (EH) and smart grid. In this regard, a subway synergism hub (SSH) as a new non-energy system is added to the smart city with the aim of serving the subway's water, heat, electrical and cooling demands as well as diminishing the operation cost of the smart city. The EH within the SSH cooperated with a desalination unit is considered to supply the subway's stations water demand by using the sea water. The investigation of the optimal allocation of the SSH unit for reducing the cost of smart city operation is also conducted by introducing a novel intelligent priority selection (IPS) analytical algorithm. In comparison to common meta-heuristic algorithms for allocation problems, the accurate optimal solution can be found in low runtime by the IPS algorithm. To achieve an accurate model of the smart city, directed acyclic graph (DAG) based blockchain approach is provided which can enhance the data and energy exchanges security within the smart city. This research paper introduces a security framework deployed in a smart city setting to establish a secure platform for energy transactions. The findings validate the effectiveness of this model and highlight the value of the IPS method. The effectiveness of the suggested approach has been assessed using the smart city system is comprised of various sections, including EVs, smart grid, microgrid, and SSH, demonstrating the credibility and accuracy of this study
Dynamics of Adrenal Steroids Are Related to Variations in Th1 and Treg Populations during Mycobacterium tuberculosis Infection in HIV Positive Persons
Tuberculosis (TB) remains the most frequent cause of illness and death from an infectious agent, and its interaction with HIV has devastating effects. We determined plasma levels of dehydroepiandrosterone (DHEA), its circulating form DHEA-suphate (DHEA-s) and cortisol in different stages of M. tuberculosis infection, and explored their role on the Th1 and Treg populations during different scenarios of HIV-TB coinfection, including the immune reconstitution inflammatory syndrome (IRIS), a condition related to antiretroviral treatment. DHEA levels were diminished in HIV-TB and HIV-TB IRIS patients compared to healthy donors (HD), HIV+ individuals and HIV+ individuals with latent TB (HIV-LTB), whereas dehydroepiandrosterone sulfate (DHEA-s) levels were markedly diminished in HIV-TB IRIS individuals. HIV-TB and IRIS patients presented a cortisol/DHEA ratio significantly higher than HIV+, HIV-LTB and HD individuals. A positive correlation was observed between DHEA-s and CD4 count among HIV-TB individuals. Conversely, cortisol plasma level inversely correlated with CD4 count within HIV-TB individuals. M. tuberculosis-specific Th1 lymphocyte count was increased after culturing PBMC from HIV-TB individuals in presence of DHEA. We observed an inverse correlation between DHEA-s plasma level and Treg frequency in co-infected individuals, and CD4+FoxP3+ Treg frequency was increased in HIV-TB and IRIS patients compared to other groups. Strikingly, we observed a prominent CD4+CD25-FoxP3+ population across HIV-TB and HIV-TB IRIS patients, which frequency correlated with DHEA plasma level. Finally, DHEA treatment negatively regulated FoxP3 expression without altering Treg frequency in co-infected patients. These data suggest an enhancing role for DHEA in the immune response against M. tuberculosis during HIV-TB coinfection and IRIS
Introduction of W-doped ZnO nanocomposite as a new and efficient nanocatalyst for the synthesis of biscoumarins in water
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