51,151 research outputs found

    Investigation of New Actinium Complexation Systems for Therapeutic Applications

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    This thesis is devoted to the synthesis of new chelating agents for actinium and actnoids (An), as part of a research effort to the production of new radio immune drugs. The first part is dedicated to the synthesis of the first member of a brand new class of An chelating agents based on dendrimers. These compounds are particular interesting because they can give drugs with an higher dose load (i.e. with more than one An atom bound by the same chelating agent), extremely difficult to be realized with traditional methodology. The identified target molecule is benzoyl-(Glu)G3-OEt a dendrimer of glutamic acid. The second part is dedicated to the synthesis of new nitrogenated chelating agents. New synthetic ways for the synthesis of N-nitroso compounds are inspected. These species have been chosen by using one of the synergic strategies nowadays so widely recommended in industrial management manuals. In fact their complexing properties toward transition metals and lanthanoids are well known and it is of scientific and applicative interest to synthesize new suitable chelating agents to make possible the study of their chelating affinity towards An. At the same time, they can be used as both starting material for the synthesis of hydrazinic chelating agents and synthetic scaffolds for the synthesis of a wide range of pendant-type-macrocyclic bifunctionalised chelating agents. The third part is dedicated to the identification of new synthetic pathway towards classical pendant-type macrocyclic bifunctionalised chelating agents

    A process yields large quantities of pure ribosome subunits

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    Development of process for in-vitro protein synthesis from living cells followed by dissociation of ribosomes into subunits is discussed. Process depends on dialysis or use of chelating agents. Operation of process and advantages over previous methods are outlined

    Efficacy of preheated chelating agents on calcium ion removal from instrumented root canals

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    The heating of chelating agents such as EDTA increases dentin wettability by decreasing surface tension. However, the calcium ion release effect of preheated chelating agents in instrumented root canals has not yet been mentioned. In this s

    Analysis, characterization, and effects of heavy metal chealating agents in water

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    Students supported: 5 Student Assistants"The term 'chelating agents' refers to chemical ligands which bind to an element with more than one site. It is a ubiquitous term, since there are multitudes of compounds which fulfill the requirements for being called chelating agents. Their origin is both synthetic and natural, and the manner and fashion in which they bind is quite varied. Many of the vitamins and hormones essential to life are chelating agents. Chlorophyll, which is required for photosynthesis, consists of a porphyrin ring structure bound to magnesium. Hemoglobin binds iron in a similar pattern, and vitamin B-12 utilizes cobalt in the same fashion. In addition to these, there are quite a number of similar compounds in both plants and animals. Most metals transport and usage inside living things involve a chelation process. In natural water systems, the presence of chelating agents can have significant impact on the transport and toxicity of metals."--IntroductionProject # B-095-MO Agreement # 14-31-0001-409

    Influence of chemical speciation on the separation of metal ions from chelating agents by nanofiltration membranes

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    The simultaneous separation of various metal ions (nickel, copper, calcium, and iron) from chelating agents (EDTA and citric acid in water streams using Nanofiltration membranes is analyzed. Assuming that multiply-charged species are highly rejected, chemical speciation com-10 putations reproduce the observed patterns of metal and ligand rejection at different pH values and concentrations.Postprint (updated version

    Effect of chelating agents on phytoextraction of Ni from contaminated Soil by Zea mays

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    The effects of application of CDTA, (CA), DTPA, NTA and FYM on the growth of Zea mays and its Ni uptake and accumulation were investigated using the pot-culture experiments. Application of chelating agents decreased the dry matter yield of roots of Zea mays while, higher values of dry matter yield (11.35 g pot-1) was observedin case of FYM sewage sludge amended soil at 80 days after sowing. FYM addition was found beneficial as compared to control (Ni90). Dry matter yield of shoots of Zea mays increased over control due to application of CDTA and FYM. The highest value of dry matter yield of shoot (86.05 g pot-1) was observed in case of CDTA withsewage sludge amended soil at 80 days after sowing. Whereas reverse trend was observed in NTA, CA and DTPA treated soils. Chelating agents enhanced the Ni uptake by both roots and shoots, higher values of Ni uptake by roots (3415.44 ?g pot-1 ) and shoots (10104.98 ?g pot-1 ) Was observed in NTA and CDTA treated soil after 80 days of sowing in amended as compared to sewage sludge unamended soil. Application of CDTA followed by NTA was found more effective in enhancing the Ni uptake by Zea mays roots and shoots than any other chelating agents at both the growth stages. The chelating agents are found useful in enhancing phytoextractability of Ni by Zea mays. Hence, marginally Ni contaminated soil may be remediated by adding chelating agents

    Lead induced dyslipidemia: The comparative effects of ascorbate and chelation therapy

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    To investigate the comparative effects of ascorbate and chelating agents on some markers of lipid metabolism in lead exposed rats, 35 male Wistar rats were used. They were grouped randomly into five (n=7); 28 of which were administered 75 mg/kg body weight lead acetate (PbAc) orally for 14 days after which their blood samples were assayed for lead. Three of the groups were further administered 30 mg/kg body weight D-penicillamine (D-pen), 30 mg/kg body weight succimer (DMSA) and 500 mg/kg body weight ascorbate (Asc) daily orally, respectively. The control group was however administered normal saline. The blood lipid profiles were determined spectrophotometrically. Lead exposure resulted in significant dyslipidemia (p < 0.05), characterized by 50% hypercholesterolemia and hypertriglyceridemia and 132% hyperphospholipidemia (plasma) while in the red blood cells, hypocholesterolemia and hypophospholipidemia were observed. During the therapeutic doses, the groups administered chelating agents and Asc showed a significant amelioration in the plasma and red blood cell levels of total cholesterol, triacylglycerols and phospholipids in the order, DMSA > Asc > D-pen. Decrease in blood lead levels after therapy indicated that the chelating agents have an advantage over Asc. The study indicates that administration of the antioxidant, Asc may not be more efficacious than the chelating agents but could be a cheaper and more convenient therapy for lead toxicity.Keywords: Ascorbate, chelating agents, dyslipidemia, lead exposure, plumbismAfrican Journal of Biotechnology Vol. 12(15), pp. 1845-185
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