The present study presents, for the first time, the amounts of nitrate, nitrite and volatile N-nitroso compounds in saliva and urine samples of Schistosoma haematobium and Schistosoma mansoni infected patients. Mid-morning saliva and 24 h urine samples were collected from male patients infected with S.haematobium (n = 129 saliva and 79 urine samples) and S.mansoni (n = 64 saliva and 65 urine samples) and in a comparative control group of healthy individuals (n = 27) from the Nile Delta region of Egypt. Saliva samples were analyzed for the presence of nitrate and nitrite; while urine samples were analyzed for the presence of nitrate, nitrite and volatile N-nitroso compounds. In the control group, N-nitroso-dimethylamine (NDMA) was detected at concentrations (mean +/- SD) of 0.27 +/- 0.47 microgram/day. N-Nitrosopiperidine (NPIP; 0.6 microgram/day) and N-nitrosopyrrolidine (NPYR; 0.4 microgram/day) were also present in one sample. S.mansoni infected subjects showed significantly (P < 0.001) higher levels of 2.9 +/- 2.9 micrograms/day NDMA and a higher frequency of NPIP (in 40/65 samples; 0.4 +/- 0.3 microgram/day) and NPYR occurrence (in 59/65 samples; 0.9 +/- 0.9 microgram/day). Significant further increases in the excretion of volatile N-nitroso compounds were found in S.haematobium-infected patients with mean daily excretion of 19.2 +/- 21 micrograms/day NDMA (in all samples; P < 0.001), 1.6 +/- 2.3 micrograms/day NPIP (in 56/79 samples; P < 0.001) and 1.3 +/- 1.9 micrograms/day NPYR (in 58/79 samples; P < 0.1). The differences either in salivary nitrite/nitrate or in urinary nitrite between the three distinct groups were not significant. However, the urinary excretion of nitrate was elevated from 139 +/- 82 mg/day in the control group to 249 +/- 126 mg/day in S.mansoni infected patients (P < 0.001) and to 174 +/- 176 mg/day in S.haematobium infected subjects (P < 0.005 in comparison to S.mansoni infected group). These results suggest a possible role of N-nitroso compounds in the etiology of schistosome-associated bladder cancer and imply a partial participation of S.mansoni in the multistage process of urinary schistosomiasis-associated bladder carcinogenesis.

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Al-20 wt% Zn samples were obtained at room temperature by rapid cooling from the melt. The quenched samples were aged at different temperatures below and above the transformation temperature (503 K) for 2 h, then quenched to room temperature. Structure variations and changes in internal friction, thermal diffusivity, Young's modulus and resistivity were traced for these testing conditions. The different results were explained in terms of the thermally induced structures in the alloy.

The effect of the vulcanizing system on the mechanical properties of butyl rubber/ethylene propylene diene monomer-general purpose furnace black-(GPF) blends was studied with static and dynamic mechanical measurements for these blends. The classical theory of elasticity was applied to show the mechanical behavior of the rubber-polymer blend and to calculate the degree of crosslinking. From the dynamic mechanical measurements, the elastic modulus, internal friction, and thermal diffusivity were calculated. The observed variations were explained in view of the role played by both the vulcanizing system and the reinforcing carbon black.

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N-substituted chitosan derivatives were synthesized through condensation with a number of selected aryl and heteroaryl aldehydes. The synthesis of the amino-derivatives has been carried out by reductive amination with sodium borohydride as reducing agent. Their structures were characterized by (FT-IR, 1 HNMR, and XRD). The antimicrobial activity of Chitosan Schiff's base (CSB) derivatives were investigated against four types of bacteria and two crop-threatening pathogenic fungi, and the results indicated that the antibacterial and antifungal activities of the investigated derivatives are very promising. Additionally, different concentrations of the triazolo-Schiff's base derivative 3c were used for cytotoxicity screening against Human Breast Adenocarcinoma Cells (MCF-7), Human Colon Carcinoma Cells (HCT-116), and Human Hepatocellular Liver Carcinoma Cells (HepG-2), and the obtained data revealed that the examined compounds have an excellent cell growth inhibitory effects on the cell lines as compared to standard.

Structures and chemical equilibria of 5-carboxy-2-thiouracil (1), 5,6-diphenyl-3-hydroxy-1,2,4-triazine (2),  1-phenyl-3-methyl-5-pyrazolone (3) and 2-mercapto-4,6-dimethylpyrimidine hydrochloride (4) are reported. Their electronic transitions are assigned and pK values are evaluated and discussed.