Muhammad Yaseen

Synthesis and relaxivity measurement of porphyrin-based Magnetic Resonance Imaging (MRI) contrast agents

Magnetic Resonance Imaging (MRI) has become a prominent imaging technique in medicine. MRI contrast agents are used to increase the sensitivity of this technique. Recently, a new method for cancer treatment with a less side effect called photodynamic therapy (PDT) has been introduced. In this method cancer tissues are selectively destroyed without injuring the surrounding healthy cells. However, for the successful use of this method, the selection of an appropriate photosensitizer is important. Hence, diagnosis-treat union of MRI and PDT will be significantly promoted if a new family of bi-functional agents is found, which would combine the effects of a contrast agent in MRI and of a photosensitizer in PDT. It will bring great improvement to the cancer diagnosis and treatment. Porphyrins have proved to be useful photosensitizing agents in PDT due to their promising photophysical efficiency and a less side effect. This work briefly describes the research development of porphyrins as a photosensitizer applied in PDT, and also highlights the recent progress in the research on bi-functional agents of MRI-PDT. Diethylenetriamine pentaacetic acid (DTPA) units are incorporated at a meso-position of the porphyrin ring to synthesize new bi-functional agents of MRI-PDT with sufficient water solubility and high relaxation potency. Gd3+ complexes are prepared by the reaction of the high molecular weight porphyrin-based ligand with GdCl3·6H2O. The longitudinal relaxivity measurement indicates 154% and 251% enhancement compared to that of the widely used MRI contrast agent Gd-DTPA. These results indicate that the two complexes could possibly be used as bi-functional agents of MRI-PDT.

Desulfurization of liquid fuels by air assisted peracid oxidation system in the presence of Fe-ZSM-5 catalyst

Catalytic oxidative desulfurization of the model oil or synthetic sulfur oil (SSO) and the different real/industrial industrial oil fractions was investigated using air assisted hydrogen peroxide and formic acid oxidation in the presence of Fe-ZSM-5 as catalyst. The reactivity of the different model sulfur compounds increased in the order of thiophene< dibenzothiophene (BT)<4-methyl dibenzothiophene (4-MDBT). The desulfurization yield in case of the model oil was increased in the presence of Fe-ZSM-5 and the sulfur content of the model oil was reduced from 1275 to less than 50 ppm in 60 min at 60 °C temperature. The catalyst also performed efficiently in ODS of real industrial oil fractions, i.e., untreated naphtha (UN), light gas oil (LGO), cooker derived combined heavy gas oil (HGO) and Athabasca oil sands derived bitumen (At. Bit.), and sulfur removal of 80, 78, 62 and 60% was attained, respectively. Kinetic investigation revealed that the ODS catalyzed by Fe-ZSM-5 followed the first-order kinetics.

Integrated nutrient management for better quality and yield of Kinnow mandarin

ABSTRACT This study was carried out to determine the integrated effect of organic matter alone and in combination with chemical fertilizers in order to maintain the nutritional status in Kinnow fruit plants. Lahore Compost was used as a source of organic matter. Treatments were made by using compost alone and in combination with nitrogen, phosphorus, potassium (NPK), and well-rotten farm yard manure (FYM; cow dung). Treatments were applied before flowering and after fruit set. Effect of these treatments on different physicochemical characteristics of Kinnow fruit and nutritional status in tree leaves was determined. Among all treatments, minimum flower drop, maximum yield, and better fruit quality were recorded in plants where 40 kg compost + 1/2 recommended doses of NPK were applied before flowering and after fruit setting, while minimum fruit set was recorded from the plants where 30 kg compost alone was applied before flowering.

SOLVENT DEGRADATION IN CO2 CAPTURE PROCESS FROM POWER PLANT FLUE GAS

The chemical absorption of CO2 by monoethanolamine for CO2 separation from other gases produced by burning fossil fuels in power plants was considered. The factors that influence the process of decomposition of monoethanolamine were studied. It was shown that addition of piperazine to the system reduces the decomposition rate of monoethanolamine during CO2 absorption from the flue gases, which are formed in an oxidizing atmosphere.