43 research outputs found
Photochemical oxidation of short-chain polychlorinated n-alkane mixtures using H2O2/UV and the photo-Fenton reaction.
No full textThe photochem. oxidn. of short-chain polychlorinated n-alkane (PCA) mixts. were studied using H2O2/UV and modified photo-Fenton conditions (Fe3+/H2O2/UV) in both Milli-Q and lake water. All PCA mixts., including chlorinated (Cl5 to Cl8) decanes, undecanes, dodecanes and tridecanes degraded in 0.02M H2O2/UV at pH 2.8 in pure water, with 80 ± 4% disappearance after 3 h of irradn. using a 300. nm light source. Degrdn. was somewhat enhanced under similar conditions but in natural water. The modified photo-Fenton system was more effective in degrading PCAs, with 72% and 80% disappearance of chlorinated decanes in 4 S min of irradn. in pure and natural water, resp. Carbon chain-length had minimal effect on degrdn. rates; however, increased degree of chlorination (from Cl5 to Cl8) resulted in slower initial degrdn. rates and less complete conversion after 3 h of irradn. Three hours of irradn. in natural water/H2O2/UV resulted in 95% degrdn. of parent PCAs accompanied by 93% release of chloride ion. Quant. dechlorination, which may be indicative of complete mineralization, suggests that this is an effective water remediation technique for PCAs
Photocatalytic degradation of 1,10-Dichlorodecane in Aqueous suspensions of TiO2: a reaction of Adsorbed chlorinated alkane with Surface hydroxyl radicals.
No full text1,10-Dichlorodecane (D2C10) is shown to be effectively photodegraded in aqueous suspensions of TiO2 using a photoreactor equipped with 300 nm lamps. Solutions exposed to UV light intensities of 3.6 × 10-5 Ein L-1 min-1, established by ferrioxalate actinometry, showed negligible direct photolysis in the absence of TiO2. The degradation rate was optimal with 150 mg/L of TiO2 and a D2C10 concentration (240 μg/L) approaching its solubility limit. Kinetics of photodegradation followed a Langmuir−Hinshelwood model suggesting that the reaction occurred on the surface of the photocatalyst. The presence of h+vb and OH• radical scavengers, including methanol and iodide, inhibited the degradation supporting a photooxidation reaction. Electron scavengers (Ag+, Cu2+, and Fe3+) had small effects on the degradation rate. The lack of transformation of D2C10 in acetonitrile as solvent indicated that the major oxidants were OH• radicals. The presence of tetranitromethane, effectively eliminating the formation of free OH• radicals, did not affect the degradation rates significantly. This result, combined with observed increases in photolysis rates with the degree of adsorption of D2C10 onto the surface of the photocatalyst, confirmed that the reaction involved adsorbed 1,10-dichlorodecane and surface bound OH• radicals
Homogeneous degradation of 1,2,9,10-tetrachlorodecane in aqueous solutions using hydrogen peroxide, iron and UV light
No full textThe homogeneous degradation of the polychlorinated n-alkane, 1,2,9,10-tetrachlorodecane (T4C10), was studied in aqueous solutions of hydrogen peroxide, including Fenton and photo-Fenton reaction conditions. All solutions were adjusted to a pH of 2.8 and an ionic strength of 0.1 M NaClO4 prior to photolysis. T4C10 (2 x 10(-6) M) was substantially degraded by the H2O2/UV system (1.0 x 10(-2) M H2O2), with 60% disappearance in 20 min of irradiation in a photoreactor equipped with 300 nm lamps of light intensity 3.6 x 10(-5) Ein L(-1) min(-1) (established by ferrioxalate actinometry). The reaction produced stoichiometric amounts of chloride ion indicating complete dechlorination of the chlorinated n-alkane. T4C10 degraded very slowly under Fenton (Fe2+/H2O2/dark) and Fenton-like (Fe3+/H2O2/dark) conditions. However, when the same solutions were irradiated, T4C10 degraded more rapidly than in the H2O2/UV system, with 61% disappearance in 10 min of exposure. The rapid degradation is related to the enhanced degradation of hydrogen peroxide to oxidizing *OH radicals under photo-Fenton conditions. Degradation was inhibited in both the H2O2/UV and photo-Fenton systems by the addition of KI and tert-butyl alcohol due to *OH scavenging
Study of the Heavy Elements of the Al-Kharazi Water Course Inside the University of Mosul
No full textThis study investigated the levels of heavy metal contaminants (copper, zinc, cadmium, and lead) in water samples collected from the Al-Kharazi watercourse traversing the University of Mosul campus over four seasons in 2022 and 2023. Water samples were taken from five stations along the watercourse and analyzed for dissolved and particulate phases of the heavy metals. The heavy metals have been extracted using a standard method and their concentrations in river water and sediments have been estimated using Atomic Absorption Spectrophotometer. The results showed mean concentrations of 0.0527 ± 0.0131 mg/L for cadmium, 0.0178 ± 0.0051 mg/L for lead, 0.0145 ± 0.002 mg/L for dissolved copper, and 3.232 ± 0.635 mg/L for zinc across all seasons. Substantial discrepancies were noted among seasons and across various sampling sites. At specific sites and during certain seasons, the levels of cadmium and lead were discovered to surpass the drinking water guidelines set by the World Health Organization (WHO). The research shows that there is a significant amount of heavy metal pollution, particularly cadmium, in the Al-Kharazi watercourse. This contamination is most likely caused by human activities in the university area. It is advisable to regularly assess and apply solutions to mitigate the risks of heavy metal contamination to both the aquatic environment and human health
Study of the Heavy Elements of the Al-Kharazi Water Course Inside the University of Mosul
No full textThis study investigated the levels of heavy metal contaminants (copper, zinc, cadmium, and lead) in water samples collected from the Al-Kharazi watercourse traversing the University of Mosul campus over four seasons in 2022 and 2023. Water samples were taken from five stations along the watercourse and analyzed for dissolved and particulate phases of the heavy metals. The heavy metals have been extracted using a standard method and their concentrations in river water and sediments have been estimated using Atomic Absorption Spectrophotometer. The results showed mean concentrations of 0.0527 ± 0.0131 mg/L for cadmium, 0.0178 ± 0.0051 mg/L for lead, 0.0145 ± 0.002 mg/L for dissolved copper, and 3.232 ± 0.635 mg/L for zinc across all seasons. Substantial discrepancies were noted among seasons and across various sampling sites. At specific sites and during certain seasons, the levels of cadmium and lead were discovered to surpass the drinking water guidelines set by the World Health Organization (WHO). The research shows that there is a significant amount of heavy metal pollution, particularly cadmium, in the Al-Kharazi watercourse. This contamination is most likely caused by human activities in the university area. It is advisable to regularly assess and apply solutions to mitigate the risks of heavy metal contamination to both the aquatic environment and human health
Postoperative urinary retention after general and spinal anesthesia in orthopedic surgical patients
No full textAbstractBackgroundAfter general, spinal anesthesia and surgery, urinary retention is common. The aim of the study was to compare the effect of general anesthesia versus spinal anesthesia on postoperative urinary retentionPatients and methodsAfter obtaining local ethics committee approval and written consent, 60 male patients, aged 16–40years, ASA – physical status I and II were divided into two groups (S) 40 patients and (G) 20 patients undergoing surgery of the lower limb lasting up to 90min (knee arthroscopy, internal tibial fixation with plate and screws). Group (S) was taken spinal anesthesia, this group was divided into two groups (S1) 20 patients, who were taken plain bupivacaine and group (S2) 20 patients who were taken plain bupivacaine plus fentanyl. Group (G) 20 patients were anesthetized by general anesthesia.ResultsThere were statistically significant differences among groups S1, S2 and G regarding spontaneous micturition, residual volume and time since spinal or general anesthesia till micturition. The percent numbers of patients with retention were 20% in group S1, 35% in group S2 and 8% in group G.ConclusionUrinary retention is more common after spinal than general anesthesia in orthopedic patients. Adding narcotics to the local anesthetics intrathecally causes more incidence of postoperative urinary retention, which may delay patients discharge and transabdominal ultrasonography is a reliable, noninvasive, inexpensive and simple method to measure bladder volume postoperatively
Synthesis, characterization and biological studies of chromene derivatives
No full textIn this thesis, a series of novel chromene derivatives based on three different moieties of biologically active compounds were synthesized and their antimicrobial and cytotoxic activities were evaluated in vitro. The fluorescent 8-amino-10-phenyl-5-hydroxy-2-oxo-4-propyl-2H, 10H-pyrano [2,3-f] chromene-9-carbonitrile derivatives 2.2(a-j) were synthesized in good yields and with good fluorescence quantum yields (ΦF). The structures were confirmed on the basis of their spectral data and elemental analysis. The antimicrobial activity was investigated and tested against several human pathogens: Gram-positive, Gram-negative bacteria and fungi as well as mycobacterium using agar well diffusion method. Minimum inhibitory concentrations were reported against each pathogen. All compounds showed significantly potent antimicrobial activities against most bacterial strains compared to reference drugs. Due to their structural similarity to reference drugs clorobiocin and novobiocin, docking experiments in the ATP binding pocket of DNA gyrase B enzyme revealed that the compounds mostly have the same binding mode as the reference drugs. Moreover, the cytotoxic activity was also evaluated against four different human cell lines and exhibited more potency than the reference drug. Several new 8-amino-10-phenyl-5-hydroxy-2-(4-hydroxyphenyl)-4-oxo-3,4-diydro-2H,10H-pyrano[2,3-f] chro-mene derivatives 3.2(a-g) were synthesized in good yield. The structures of these derivatives were established on the basis of IR, 1H NMR, 13C NMR, 1H-1H COSY, HSQC, HMBC and elemental analysis. All new synthesized compounds were evaluated for in vitro antimicrobial and cytotoxicity activities. Their antimicrobial activity was investigated and tested with seven human pathogenic Gram-positive and Gram-negative bacteria, four fungi and one mycobacterium, using agar well diffusion method, and minimum inhibitory concentrations were reported. Most of the new tested compounds exhibited significant potent antimicrobial activities against most bacterial strains compared to reference drugs. Some of these new synthesized derivatives exhibited the highest inhibitory activity against Pseudomonas aeruginosa (RCMB 010043), Escherichia coli (RCMB 010052) compared to reference drugs. On the other hand, three of these new compounds were found to be more effective against Salmonella typhimurium. The antibacterial activity of most compounds was found to be comparably active to reference drugs against Gram-positive bacteria, while compound 3.2c did not show any antimicrobial activity. The cytotoxic activity was also evaluated against four different human carcinoma cell lines and exhibited good cell growth inhibitory activity against HCT-116 cell line. The molecular modeling results showed binding interaction of some new synthesized compounds in the active site of Gyrase B. A variety of novel derivatives of 2-amino-6-(4-ethoxyphenylazo)-4(-phenyl)-4H-benzo[h]chromene-3-carbonitrile 4.2(a-j) have been prepared via three component reactions. The structures were confirmed on the basis of their spectral data and elemental analysis. Their antimicrobial activity was investigated and tested against four human pathogen Gram-positive and Gram-negative bacteria and four fungi. Some newly prepared compounds exhibited antimicrobial activities against Gram-negative bacteria and fungi species compared to reference drugs. The bathochromic shift of compound 4.2a was shown in solution when acidified. Moreover, the cytotoxic activity was also evaluated against three different human cell lines. Some tested compounds have good IC50 against HCT-116 and MCF-7 cell lines. The molecular modeling results showed binding interaction of some new synthesized compounds in the active site of Gyrase B
Effect of Laser Pulses and Energy on the Structural Properties of ZnO Thin Film Prepared using PLA Technique
No full textIn this work, zinc oxide (ZnO) thin film has been fabricated on glass substrate using pulse laser ablation (PLA) technique. The effect of laser pulses of 1000, 1500, 2000 pulses at laser energy 700 mJ as well as, laser energy of 600, 700, and 800 mJ at fixed laser pulses of 1500 pulse, with methanol as a solvent on the structural properties of prepared films using XRD, SEM and EDX. XRD results revealed that the ZnO thin films have hexagonal structure with polycrystalline in nature with preferred orientation of (002). Crystalline size was increased to be 2.6, 4.4, and 5.8 nm with the increasing of the pulses of 1000, 1500, and 2000 respectively, and at lowest crystalline size of 2.86 nm with nanostructure like tree leaf have been seemed at energy of 700 mJ and laser pulses of 1500 pulse. In addition, narrow FWHM and no phase change have been observed in all cases. SEM images showed that for all cases the films were homogenous with some island and cluster then cracking started to obtain with the increasing of increase the pulse number. EDX analysis showed that the prepared films were free of defects and contaminations
Photochemical oxidation of short-chain polychlorinated n-alkane mixtures using H2O2/UV and the photo-Fenton reaction
No full textThe photochemical oxidation of a series of short-chain polychlorinated n-alkane (PCA) mixtures
was investigated using H2O2/UV and modified photo-Fenton conditions (Fe3+/H2O2/UV) in both Milli-Q and lake water. All PCA mixtures, including chlorinated (Cl5 to Cl8) decanes, undecanes, dodecanes and
tridecanes degraded in 0.02 M H2O2/UV at pH 2.8 in pure water, with 80±4% disappearance after 3 h of irradiation using a 300 nm light source. Degradation was somewhat enhanced under similar conditions but
in natural water. The modified photo-Fenton system was more effective in degrading PCAs, with 72% and 80%
disappearance of chlorinated decanes in 45 min of irradiation in pure and natural water, respectively. Carbon
chain-length had minimal effect on degradation rates; however, increased degree of chlorination (from Cl5 to Cl8) resulted in slower initial degradation rates and less complete conversion after 3 h of irradiation. Three
hours of irradiation in natural water/H2O2/UV resulted in 95% degradation of parent PCAs accompanied by
93% release of chloride ion. Quantitative dechlorination, which may be indicative of complete mineralization,
suggests that this is an effective water remediation technique for PCAs
A comparative study between Kuwait’s Government and Private Sector Primary Schools in methods of teaching and pupils’ achievement in mathematics
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The study aimed at identify the aspects associated with teaching mathematics and students’ learning through The framework for the scientific and theoretical features and properties related to: a) teaching mathematics in primary school, b) mathematics students' achievement and educational environment attributes, schools and teachers, c) nature of primary education in private and governmental schools, d) The differences between them in Kuwait in light of fifth primary class teaching methods and skills, and student learning and factors that affect it. Study sample included (20) mathematics teachers, all of whom taught fifth grade pupils from three primary schools in Kuwait (one private and two public; one for boys and the other for girls). Of these twenty, (10) were mathematics teachers in public primary schools and the other (10) were in the private primary school. Also, a sample of (80) pupils were chosen from fifth grade primary consisting of (50) pupils from the public schools (25 boys and 25 girls) and the remaining (30) pupils from the private schools (15 boys and 15 girls). Many tools were administered: a) a pilot study to define the problem and confirm the validity of the research questions ;b) questionnaire for teachers to elicit information concerning the teaching methods employed; c) Collation of pupils’ achievement data to define and discover the differences between pupils’ achievement. A number of statistical tools from the SPSS package for analysing social research data were used, the most important of which were: Cronbach's Alpha; Frequencies and percentages; and T test. Result showed that there are statistical differences between the government and private schools concerning: the attributes and characteristics of the methods of teaching mathematics; the mathematics curriculum; the components of the educational and scholastic environment; and the students' achievement. there are no statistical differences between the government and private schools concerning: the teacher's perception of student's achievement; and the teacher's skills
