Amino derivatives of polycyclic aromatic hydrocarbons are well-known chemical carcinogens which should be carefully monitored in our environment. They are amenable to anodic oxida- tion on suitable solid or paste electrodes. This fact was exploited for voltammetric determina- tion of 4-aminobiphenyl on unmodified carbon paste electrode and carbon paste electrodes modified by montmorillonite and sepiolite. The optimum pH of BR buffer for measurement on unmodified carbon paste electrode is pH 2, pH 10 for CPE-SEP and pH 11 for CPE-MMT. It was possible to increase sensitivity of the determination using adsorptive stripping voltam- metry on modified electrodes. The optimum time for accumulation of 4-aminobiphenyl is 5 minutes. The limits of quantification of the order of 10−6 mol dm−3 were obtained for each electrode. After accumulation, the limits of quantification decreased to the 10−7 mol dm−3 . The newly developed method was tested for the determination of 4-aminobiphenyl in model sam- ples of drinking and river water, reaching limits of quantification of the order of 10−7 mol dm−3 .

No description available.

Estrogen-regulated synthesis of vitellogenin (Vg), a yolk-protein precursor required for reproduction, was monitored to explore the potential antiestrogenic effects of the coplanar polychlorinated biphenyl (PCB), 3,3',4,4',5,5'-hexachlorobiphenyl (3,4,5-HCB), in juvenile rainbow trout (Oncorhynchus mykiss). The effects of 17β-estradiol on 3,4,5-HCB induction of cytochrome P4501A (CYP1A) were also examined. Trout were injected with 3,4,5-HCB (0.25, 2.5, 25, 50, or 100 mg/kg) or a vehicle control, and after 10 weeks, they were sampled or injected with 17β-estradiol (0.1 mg/kg). Markers of vitellogenesis, such as liver somatic index, hepatic estrogen- binding sites, and plasma Vg concentrations, in 17β-estradiol-treated fish were not affected by 3,4,5-HCB. Maximal induction of CYP1A protein and mRNA occurred at doses above 2.5 mg/kg, and 17β-estradiol reduced CYP1A protein content at a single dose (0.25 mg 3,4,5-HCB/kg). Ethoxyresorufin-O-deethylase (EROD) activity was induced by 3,4,5-HCB doses of between 0.25 and 2.5 mg/kg, but induction was reduced at higher doses, indicating that 3,4,5-HCB suppressed CYP1A catalytic activity. In 3,4,5-HCB/17β-estradiol-treated fish, plasma estradiol was significantly reduced at 100 mg 3,4,5-HCB/kg, but the depression was not associated with CYP1A induction or with other antiestrogenic effects. Although CYP1A was induced, 3,4,5-HCB did not interfere with vitellogenesis, which suggests that the PCB congener is not a potent antiestrogen in rainbow trout.

The study reported here examined 367 adolescent 4-H participants in terms of demographic, psychological, behavioral, and relational characteristics, as well as their perceptions and experiences in 4-H. Overall, participants scored high on all outcome variables except having a diverse population in their club. Older participants were more optimistic, participated in more deviant behaviors, and were more satisfied with their 4-H experiences in comparison to younger participants. In comparison to boys, girls appeared to be healthier in regards to psychological characteristics, positive behaviors, and relationships with peers and other adults and were more satisfied with their 4-H experiences.

AIMS OF THE STUDY: 1. To perform a retrospective, epidemiological analysis of cases of reactive lymphadenopathy and atypical reactive lymphoid hyperplasia (ARLH) received in the Department of Anatomical Pathology, UCT and GSH, over a 5 year period, in order to determine the number of cases of ARLH, and the frequency of the various subtypes of reactive lymphoid. hyperplasia, so as to provide base-line information for further studies. 2. To set up IN SITU HYBRIDIZATION (ISH) for detection of Epstein-Barr virus (EBV)-encoded RNA's (EBERs) in latently infected cells in selected cases, to determine if virus is present in ARLH. 3. To perform immunohistochemical analysis for the detection of EBY-derived latent membrane protein (LMP) in those cases subjected to ISH.

Students should be given the opportunity to learn about, through, and for democracy in order to be able to act in the present and the future. In the subject of social studies, students should be given the opportunity to develop factual knowledge about democracy, and this should be done through democratic methods. According to Curriculum for the compulsory school, preschool class and the leisure-time centre Lgr 22 (the Swedish curriculum, 2022a), stu- dents should be developed into democratic citizens with good values and skills. In order for students to develop into that, they need to learn about, through and for democracy. When students acquire factual knowledge about democracy and learn through democratic methods, they learn for democracy, and both of the school's main missions are pursued. To answer the purpose and research questions regarding how the democracy mission is de- scribed in textbooks for social studies in grades 4-6, Biesta and Dewey's views on educa- tion and democracy are used.The study was conducted using a qualitative method in the form of a qualitative text anal- ysis of the textbooks. The collected data from the seven textbooks generated an analysis of text and tasks to determine how the democracy mission was presented and described. The results showed that parts of the democracy mission were presented in all textbooks, but there were two textbooks that presented the entire mission about, through, and for de- mocracy. It emerged that the teacher's role in instruction is important for students to be given the opportunity to learn about the democracy mission, as not all textbooks covered the entire mission. / Elever ska ges möjlighet att lära om, genom och för demokrati för att kunna verka i samti- den och framtiden. I samhällskunskapsämnet ska elever ges möjlighet att utveckla fakta- kunskaper om demokrati och detta genom demokratiska arbetssätt. Läroplan för grundsko- lan, förskoleklassen fritidshemmet Lgr 22 (Skolverket, 2022a) skriver att elever ska ut- vecklas till demokratiska medborgare med goda värderingar och färdigheter. För att elever ska utvecklas till det behöver de lära sig om, genom och för demokrati. När elever får faktakunskaper om demokrati och lära genom demokratiska arbetssätt lär de sig för demo- krati och hela skolans två huvuduppdrag arbetas utifrån. För att besvara studiens syfte och frågeställningar kring på vilka sätt och hur demokratiuppdraget beskrivs i läromedel för samhällskunskap i årskurs 4–6 används Biesta och Deweys syn på utbildning och demo- krati.Studien genomfördes med en kvalitativ metod i form av en kvalitativ textanalys av läro- medel. Insamlade data från de sju läromedlen genererade i en analys av text och uppgifter för att få fram hur demokratiuppdraget framställdes och beskrevs. Resultatet visade på att delar av demokratiuppdraget framställdes i alla läromedel men det var två läromedel som framställde hela uppdraget om, genom och för demokrati. Det framkom att lärarens roll i undervisningen är viktig för att elever ska ges möjlighet att lära kring demokratiuppdraget då alla läromedel inte täckte hela uppdraget.

Wastewater from the manufacture of propellants typically contains 2,4-dinitrotoluene (DNT), a suspected animal carcinogen. Previous studies have indicated that DNT is aerobically biodegradable. However, inconsistent removal of DNT during aerobic treatment has been observed at a munitions wastewater treatment plant, necessitating the use of activated carbon pre-treatment. The objective of this study was to evaluate the effect of nutrient and cosubstrate amendments on the rate and extent of DNT removal. Addition of ethanol (100-500 mg/l) and phosphate (0.8-3.3 mg/l) significantly accelerated the rate of aerobic DNT (0.3-5.6 mg/l) biodegradation. Addition of phosphate alone also increased the rate of DNT degradation, but to a lesser degree. The presence of ethyl ether, another substrate commonly found in munitions plant wastewater, had comparatively little effect on the rate of DNT removal. Interruptions in the DNT manufacturing process can result in DNT being absent from the munitions plant wastewater for extended periods. The effect of such interruptions was evaluated in semi-continuously operated reactors, fed daily with phosphate-amended wastewater, at a hydraulic residence time of 3 days. DNT removal resumed without a lag even after it was absent from the feed for periods up to 15 days. During aerobic biodegradation of DNT, reduction to 4-amino-2-nitrotoluene and 2-amino-4-nitrotoluene was consistently observed, with reduction at the para position predominating. The highest level of aminonitrotoluene formation was 23% of the total DNT degraded. Aminonitrotoluene isomers were consumed shortly after they formed in the semi-continuously operated reactors, confirming the potential for degradation of these metabolites. Although the aminonitrotoluene isomers are not currently regulated, their presence in treated munitions wastewater is a concern due to possible toxicity. / Master of Science

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No description available.

No description available.