Physiological studies on heavy metals and blue-green algae

Mutants of Anacystis nidulans tolerant to high levels of Co, Ni,Cu, Zn and Cd were obtained by repeated subculturing at strongly inhibitory levels of metal. For instance, the level of Zn at which-1strong inhibition occurred was raised from 1.45 to 16.5 mg 1(^-1) Zn after 75 subcultures. Isolates resistant to 5.0 mg 1(^-1) Zn and 12.0 mg 1(^-1) Zn maintained their resistance for at least 72 cell generations in the absence of Zn, though there was subsequently an increased lag during the first subculture back to high Zn levels. This and plating experiment sindicate that the strains are mutants. Assays of cross-resistance of each of the five types of mutant were made to the other four metals. Inmost cases changes in cross-resistance were only slight, with about equal numbers of examples of increased and decreased resistance. Examples of marked changes were increased Co-resistance of a Cd-tolerant strain and decreased Cd-resistance of a Ni-tolerant strain. The environmental factors influencing toxicity were investigated for Cu, Zn and Cd. Increases in Ca, Mn, Fe and P reduced Zn toxicity to both wild-type and Zn-tolerant strains, but the two differed in their response to pH. Effects on morphology were evident at high metal levels with all strains. In most cases increased levels of metal led to the formation of filaments, but with Cu subspherical structures sometimes made up most of the-1population. Uptake from media enriched 0.1 and 1.0 mg 1(^-1) Zn was similar in both wild-type and Zn-tl2.0, whether judged by total Zn accumulated or by that remaining after EDTA washes. Isolates from high Zn sites were found in general to tolerate considerably higher levels of Zn than laboratory research strains(presumably isolated from environments not enriched with Zn). A comparison of the influence of Zn on nitrogen fixation by a strain from low zinc site{Anabaena cylindrica) and one from a high Zn site (Calothrix D184) showed only a slight difference when Zn was first added, but a pronounced effect after 24 h

How to Capture Reciprocal Communication Dynamics: Comparing Longitudinal Statistical Approaches in Order to Analyze Within- and Between-Person Effects

Choosing an appropriate statistical model to analyze reciprocal relations between individuals’ attitudes, beliefs, or behaviors over time can be challenging. Often, decisions for or against specific models are rather implicit and it remains unclear whether the statistical approach fits the theory of interest. For longitudinal models, this is problematic since within- and between-person processes can be confounded leading to wrong conclusions. Taking the perspective of the reinforcing spirals model (RSM) focusing on media effects and selection, we compare six statistical models that were recently used to analyze the RSM and show their ability to separate within- and between-person components. Using empirical data capturing respondents’ development during adolescence, we show that results vary across statistical models. Further, Monte Carlo simulations indicate that some approaches might lead to wrong conclusions if specific communication dynamics are present. In sum, we recommend using approaches that explicitly model and clearly separate within- and between-person effects

SYNTHESIS AND EVALUATION OF ETHYL (4-(N-(THIAZOL-2-YL) SULFAMOYL) PHENYL)CARBAMATE (TSPC) AS A CORROSION INHIBITOR FOR MILD STEEL IN 0.1M HCL

Laboratory synthesized ethyl (4-(N-(thiazol-2-yl)sulfamoyl)phenyl)carbamate (TSPC), characterized by 1H NMR spectroscopy, was evaluated as corrosion inhibitor of mild steel in 0.1M HCl using electrochemical techniques. Open circuit potential, potentiodynamic polarization and impedance spectroscopy were used to evaluate the inhibition efficiency of (TSPC) at various concentrations. The obtained electrochemical data indicated that (TSPC) acts as moderate corrosion inhibitor for mild steel in acidic media. It is found that the inhibition efficiency increases with the concentration of the inhibitor till 400ppm. The adsorption isotherm involving physisorption of (TSPC) at room temperature and the experimental data complied to the Langmuir adsorption isotherms and the negative values of the Gibb’s free energy of adsorption obtained suggested that inhibitor molecules have been spontaneously adsorbed onto the mild steel surface

Enhancing radial distribution system performance by optimal placement of DSTATCOM

In this paper, A novel modified optimization method was used to find the optimal location and size for placing distribution Static Compensator in the radial distribution test feeder in order to improve its performance by minimizing the total power losses of the test feeder, enhancing the voltage profile and reducing the costs. The modified grey wolf optimization algorithm is used for the first time to solve this kind of optimization problem. An objective function was developed to study the radial distribution system included total power loss of the system and costs due to power loss in system. The proposed method is applied to two different test distribution feeders (33 bus and 69 bus test systems) using different Dstatcom sizes and the acquired results were analyzed and compared to other recent optimization methods applied to the same test feeders to ensure the effectiveness of the used method and its superiority over other recent optimization mehods. The major findings from obtained results that the applied technique found the most minimized total power loss in system ,the best improved voltage profile and most reduction in costs due power loss compared to other methods

An extremely low-noise heralded single-photon source: a breakthrough for quantum technologies

Low noise single-photon sources are a critical element for quantum technologies. We present a heralded single-photon source with an extremely low level of residual background photons, by implementing low-jitter detectors and electronics and a fast custom-made pulse generator controlling an optical shutter (a LiNbO3 waveguide optical switch) on the output of the source. This source has a second-order autocorrelation g^{(2)}(0)=0.005(7), and an "Output Noise Factor" (defined as the ratio of the number of noise photons to total photons at the source output channel) of 0.25(1)%. These are the best performance characteristics reported to date

Myocardial tissue tagging with cardiovascular magnetic resonance

Cardiovascular magnetic resonance (CMR) is currently the gold standard for assessing both global and regional myocardial function. New tools for quantifying regional function have been recently developed to characterize early myocardial dysfunction in order to improve the identification and management of individuals at risk for heart failure. Of particular interest is CMR myocardial tagging, a non-invasive technique for assessing regional function that provides a detailed and comprehensive examination of intra-myocardial motion and deformation. Given the current advances in gradient technology, image reconstruction techniques, and data analysis algorithms, CMR myocardial tagging has become the reference modality for evaluating multidimensional strain evolution in the human heart. This review presents an in depth discussion on the current clinical applications of CMR myocardial tagging and the increasingly important role of this technique for assessing subclinical myocardial dysfunction in the setting of a wide variety of myocardial disease processes

ORGANIC FERTILIZATION AND NATURAL SUBSTANCES TREATMENTS AFFECTS CHEMICAL CONSTITUENTS OF GUAR PLANTS

This experiment was conducted at the Floriculture Nursery, Faculty of Agriculture, Minia University during the two successive seasons to study the effect of compost at rates (0, 25, 2.50 and 3.75 ton/fed.) and natural substances i.e. vitamins (ascorbic acid at 50 and 100 ppm, ?-tocopherol at 10, 20 ppm and thiamine, at 25 and 50 ppm) and active yeast at 2.5 and 5 g/l. and their interaction on some chemical constituents of guar plants. The results indicated that, Addition of compost caused an increase in guaran %, Photosynthetic pigments, Total carbohydrates (%) N, P and K (%) and Protein (%). The maximum level in all previous traits was for the plants growing in the soil fertilized with the highest level of compost (3.75 t/fed.). Using the treatments of vit. C at 50 ppm followed by 5 g/l. active yeast, then vit. E at 10 ppm gave the highest values of all previous traits. The interaction between the two main factors (A×B) was significant for guaran %, photosynthetic pigments, total carbohydrates %, N and P %., The highest values were obtained from the interaction treatments of 3.75 ton/fed., compost in combination with active yeast at 5 g/l. and vit. C at 50 ppm. On the other hand, the interaction between compost, active yeast and vitamins treatments was not significant for protein content (%). We conclude that supply guar plants with compost at 3.75 ton/fed., and spraying plants with either active yeast at 5 g/l. or ascorbic acid (vit. C) at 50 ppm to improve the values of some chemical constituents under investigation condition

ORGANIC FERTILIZATION AND NATURAL SUBSTANCES TREATMENTS AFFECTS CHEMICAL CONSTITUENTS OF GUAR PLANTS

This experiment was conducted at the Floriculture Nursery, Faculty of Agriculture, Minia University during the two successive seasons to study the effect of compost at rates (0, 25, 2.50 and 3.75 ton/fed.) and natural substances i.e. vitamins (ascorbic acid at 50 and 100 ppm, ?-tocopherol at 10, 20 ppm and thiamine, at 25 and 50 ppm) and active yeast at 2.5 and 5 g/l. and their interaction on some chemical constituents of guar plants. The results indicated that, Addition of compost caused an increase in guaran %, Photosynthetic pigments, Total carbohydrates (%) N, P and K (%) and Protein (%). The maximum level in all previous traits was for the plants growing in the soil fertilized with the highest level of compost (3.75 t/fed.). Using the treatments of vit. C at 50 ppm followed by 5 g/l. active yeast, then vit. E at 10 ppm gave the highest values of all previous traits. The interaction between the two main factors (A×B) was significant for guaran %, photosynthetic pigments, total carbohydrates %, N and P %., The highest values were obtained from the interaction treatments of 3.75 ton/fed., compost in combination with active yeast at 5 g/l. and vit. C at 50 ppm. On the other hand, the interaction between compost, active yeast and vitamins treatments was not significant for protein content (%). We conclude that supply guar plants with compost at 3.75 ton/fed., and spraying plants with either active yeast at 5 g/l. or ascorbic acid (vit. C) at 50 ppm to improve the values of some chemical constituents under investigation condition