Months In Ambient Conditions Research Articles

An UV-Visible study of the stability of the ruthenium hexaammine cation in BEA zeolites—comparison with NaY

A series of Ru/zeolites with Ru content in the range of 1–7 wt.% was prepared by cationic exchange in an aqueous Ru(NH3)6Cl3 solution, at room temperature, of two H–BEA (different particle sizes but same Si/Al ratio of 13), a Cs–BEA (Si/Al = 13) and a NaY (Si/Al = 2.4), zeolitic supports. The quantitative UV-Visible analysis of the solutions during exchange showed that about 90% of the exchange process was over within the first hour of contact between the zeolite and the solution. This analysis also provided an accurate measurement of Ru content in the solids in real time and gave access to the Ru exchange capacities of the zeolitic supports. Diffuse reflectance UV-Visible spectroscopy showed that the [Ru(NH3)6]3+ cations were exchanged as such in all the BEA zeolites and were not modified after storage of the solids for several months in ambient conditions. On the contrary, the Ru hexaammine cations in NaY were gradually transformed into the Ru-red-wine [(NH3)5RuIIIO–RuIV(NH3)4–O–RuIII(NH3)5]6+ and Ru-brown [(NH3)5RuIV–O–RuIII(NH3)4–O–RuIV(NH3)5]7+ cationic trimers, in agreement with literature data. The transformation rate increased with the Ru loading. The reasons for the higher stability of the [Ru(NH3)6]3+ cations in the BEA series than in NaY are discussed.

The Effect of Some Fungicide Treatments and Storage Regimes on the Postharvest Diseases of Citrus Fruits

Fruits of mandarin, orange, grapefruit and lemon, which received no fungicide treatment before harvest and at packing, stored at ambient temperature for 2 months, and kept at cold storage conditions for two and four months. During storage 16.8, 25.1 and 65.4 % crop losses were observed, respectively, due to development of total postharvest diseases. Citrus trees were sprayed with benomyl, fosetyl-Al, and CuSO4.5H2O+ZnSO4.6H2O+hydrated lime to control postharvest diseases 1-1.5 month before harvest time. Also, dipping of fosetyl-Al, benomyl, sodium o-phenylphenate, 2.4-D isopropyl-ester in water, and spraying of benomyl and imazalil in a water-wax were used to control for postharvest diseases of citrus fruits during packing processes. Some lemon fruits were stored in wrapped biphenyl emitted papers. Combination of preharvest fungicide treatments with treatments during packing, assumed to be the most effective control measure against postharvest diseases, resulted 2.4 % crop losses in 2 months ambient conditions, and 9.8-20.9 % in 2-4 months cold storage conditions. When compared with non treated control groups, the savings were 14.4 % in 2 months ambient conditions, and 15.3-44.5 % in 2-4 months cold storage conditions. The effect of combined treatments (some fungicide treatments in 1-1.5 month before harvest, and during packing period) on control of postharvest diseases was 89.9 aünd 60.1-72.1 % in ambient and cold storage conditions, respectively. Mandarin, orange, grapefruit and lemon fruits which were only treated during 1-1.5 month before the harvest were stored for 2 months in ambient conditions and for 4 months in cold storage rooms. In this case, total postharvest diseases were controlled at a rate of 57.5 and 40.0 %, respectively. However, in the case of fruits treated with fungicides alone in packinghouse, showed controlling levels of 68.8 and 55.1 %. The incidence of total postharvest diseases in the lemon fruits which were treated with the combined fungicide treatments and wrapped into biphenyl emitted papers stored 2 months in ambient and 2-4 months cold storage conditions were 2.5 and 0, 7.5 % and resulting disease control were 18.8 and 15.0, 33.8 %, respectively. In this study, then main postharvest diseases observed were Alternaria citri Ellis et Pierce stem end rot, Penicillium italicum Wehmer and Penicillium digitatum Sacc. blue and green molds, Colletotrichum gloeosporioides ( Penz.) Sacc. antrachnose, and Geotrichum candidum Link. ex Pers. sour rot on rotted mandarin, orange, grapefruit, and lemon fruits which were treated with the combined fungicide treatments. In combined fungicide treatments, A. citri

Role of new Antioxidants in the Stabilization of Ophthalmic and ear Dosage form Preparation of Hamycin

AbstractThe study involves the development of eye-ointment and ear-drop dosage form of hamycin, a polyene antifungal antibiotic, using anti-oxidants and stabilisers to enhance the stability of these dosage forms. It has been found that incorporation of hydroquinone (HQ), butylated hydroxy anisole (BHA), nordihydroguiaretic acid (NDGA), sodium deoxycholate (DSC) and ascorbyl palmitate (AP) in varying combinations in the dosage preparation have enhanced the stability and preserved physicochemical properties of the ointment for a period of 12 months period under refrigerated temperature (8+2°C) conditions. It was further observed that this dosage preparation is more stable in polyethylene glycol bases than in lanolin bases. Ear-drops dosage preparation has shown stability for 12 months period in the presence of BHA and in combination of other antioxidants under refrigerated temperature. However, ear-drops dosage form was found to be stable only for a period of 6months in ambient condition. It is therefore, r...