Filament identification and dominance of Eikelboom Type 0092 in activated sludge from wastewater treatment facilities in Cape Town, South Africa

Routine characterisation of activated sludge and identification of the filamentous population by microscopic and/or other non-culture dependent techniques can assist in diagnosing the aetiology of poor performance of wastewater treatment works (WWTWs). In South Africa, most facilities rely solely on physicochemical indicators, treating reactors as ‘black-boxes’, with the result that process adjustments are often delayed, to the detriment of the environment. This study was performed in order to gain insight into the filamentous population found in activated sludge in Cape Town WWTWs, to compare these with other global and local literature findings, and to build capacity in this science. Physicochemical and plant performance parameters, in terms of nutrient removal and settling, were obtained from routine operational data and assessed in conjunction with the microscopic analyses of activated sludge samples taken over a 6-month period. Hypotheses on the links between filament types and/or plant  configurations and/or operational parameters were formulated using  existing literature. In order of prevalence, the five most common dominant filament species in 96 activated sludge samples were: Eikelboom Type  0092, Eikelboom Type 1851, nocardioforms, Microthrix parvicella and  Eikelboom Type 021N. In order to compile a statistically significant  database, it is recommended that an extensive nationwide study is  conducted to link filament types with plant configurations, operational parameters and geographical locations.Keywords: activated sludge, bulking, identification, filament, Type 009

Reactions of halogens with Pt(II) complexes of N-alkyl- and N,N-dialkyl-Nʹ -benzoylthioureas: oxidative addition and formation of an I₂ inclusion compound

The treatment of cis-[PtII(L1a/b-S,O)2] complexes of N,N-diethyl- (HL1a) and N,N-di(n-butyl)-N'-benzoylthiourea (HL1b) with I2 or Br2 in chloroform, leads to rapid oxidative addition to yield several geometric isomers of [PtIV(L-S,O)2X2] (X = I, Br); the reactions can be monitored by 195Pt NMR and UV-visible spectrophotometry. The products cis-[PtIV(L1a-S,O)2I2] 6 and cis-[PtIV(L1a-S,O)2Br2] 7, which have been isolated and structurally characterized, are the first-reported crystal structures of complexes of Pt(IV) with this class of ligand. Molecules of 6 pack such that the I–Pt–I axes are essentially aligned, with unusually close nearest-neighbour iodide contacts (3.553(1) A˚ ). These short I···I intermolecular interactions lead to infinite chains of weakly connected molecules in crystals of the compound. No such interactions are evident in the corresponding crystals of 7. Reaction of the Pt(II) complex of N-propyl-N'-benzoylthiourea (H2L2a) cis-/trans-[PtII(H2L2a-S)2Br2] with Br2 also results in oxidative addition, to yield trans-PtIV(H2L2a-S)2Br4 9. By contrast, treatment of cis-/trans-[PtII(H2L2a-S)2I2] with I2 does not lead to an oxidative addition product, yielding instead an interesting iodine inclusion compound of PtII, trans-[PtII(H2L2a-S)2I2]·I2 8. In 8, short intermolecular I···I distances of 3.453(1) A˚ between I2 and coordinated iodide ions in trans-[PtII(H2L2a-S)2I2] molecules, result in infinite chains of weakly linked trans-[PtII(H2L2a-S)2I2] ···I2 groups in the lattice. However, the empirically estimated bond order of 0.75 for the included I2 molecules does not support the possible existence of discrete tetraiodide ions (I42−) in the lattice of compound 8

Sequence-based prediction for vaccine strain selection and identification of antigenic variability in foot-and-mouth disease virus

Identifying when past exposure to an infectious disease will protect against newly emerging strains is central to understanding the spread and the severity of epidemics, but the prediction of viral cross-protection remains an important unsolved problem. For foot-and-mouth disease virus (FMDV) research in particular, improved methods for predicting this cross-protection are critical for predicting the severity of outbreaks within endemic settings where multiple serotypes and subtypes commonly co-circulate, as well as for deciding whether appropriate vaccine(s) exist and how much they could mitigate the effects of any outbreak. To identify antigenic relationships and their predictors, we used linear mixed effects models to account for variation in pairwise cross-neutralization titres using only viral sequences and structural data. We identified those substitutions in surface-exposed structural proteins that are correlates of loss of cross-reactivity. These allowed prediction of both the best vaccine match for any single virus and the breadth of coverage of new vaccine candidates from their capsid sequences as effectively as or better than serology. Sub-sequences chosen by the model-building process all contained sites that are known epitopes on other serotypes. Furthermore, for the SAT1 serotype, for which epitopes have never previously been identified, we provide strong evidence - by controlling for phylogenetic structure - for the presence of three epitopes across a panel of viruses and quantify the relative significance of some individual residues in determining cross-neutralization. Identifying and quantifying the importance of sites that predict viral strain cross-reactivity not just for single viruses but across entire serotypes can help in the design of vaccines with better targeting and broader coverage. These techniques can be generalized to any infectious agents where cross-reactivity assays have been carried out. As the parameterization uses pre-existing datasets, this approach quickly and cheaply increases both our understanding of antigenic relationships and our power to control disease

Development and validation of a foot-and-mouth disease virus SAT serotype-specific 3ABC assay to differentiate infected from vaccinated animals

The effective control of foot-and-mouth disease (FMD) requires sensitive, specific and rapid diagnostic tools. However, the control and eradication of FMD in Africa is complicated by, among other factors, the existence of five of the seven FMD virus (FMDV) serotypes, including the SAT-serotypes 1, 2 and 3 that are genetically and antigenically the most variable FMDV serotypes. A key diagnostic assay to enable a country to re-gain its FMD-free status and for FMD surveillance, is the 3ABC or the non-structural protein (NSP) enzyme-linked immunosorbent assay (ELISA). Although many kits are available to detect 3ABC antibodies, none has been developed specifically for the variable SAT serotypes. This study designed a SAT-specific NSP ELISA and determined whether this assay could better detect NSP-specific antibodies from FMDV SAT-infected livestock. The assay’s performance was compared to validated NSP assays (PrioCheck®-NSP and IZSLER-NSP), using panels of field and experimental sera, vaccinated and/or infected with FMDV SAT1, SAT2 or SAT3. The sensitivity () of the SAT-NSP was estimated as 76% (70%, 81%) whereas the specificity was 96% (95%, 98%) at a 95% confidence interval. The sensitivity and specificity were comparable to the commercial NSP assays, PrioCheck®-NSP (82% and 99%, respectively) and IZSLER-NSP (78% and 98%, respectively). Good correlations were observed for all three assays.Dr FF Maree received funding from the FAO (MTF/INT/003/EEC) and the IAEA (agreement #16085). The work at CODA-CERVA-VAR was funded by the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no 226556 (FMD-DISCONVAC) and the Veterinary and Agrochemical Research Centre (CODA-CERVA), Ukkel, Belgium.http://www.elsevier.com/locate/jviromet2019-05-01hj2018Microbiology and Plant Patholog

OHphenol⋯OHalcohol hydrogen-bonding as the preferred hydrogen-bonded interaction in the crystal structures of three isomers of methylolphenol: Analysis of hydrogen-bonding interactions in phenol and alcohol containing molecules

The crystal structures of three isomers containing a phenol and an alcohol functional group, 2-methylolphenol (1), 3-methylolphenol (2) and 4-methylolphenol (3) are reported. All isomers feature heteromeric hydrogen bonded interactions, either from the phenol hydrogen to the alcohol O or from the alcohol hydrogen to the phenol O. There are no homomeric interactions present in the solid state. An analysis of 31 related compounds shows that in the literature the OHphenol⋯OHalcohol hydrogen bond is the most commonly seen heteromeric interaction in these types of compounds, and DFT calculations show that this hydrogen bond has the highest interaction energy in the three isomers. The isomer 3-methylolphenol (2) crystallizes as two concomitant polymorphs, 2a containing two molecules in the asymmetric unit, and 2b containing three molecules in the asymmetric unit, with the former slightly more stable according to DFT calculations. © The Royal Society of Chemistry 2011.Articl

Bestuur in verpleging : 'n teoretiese model

Proefskrif (M. Verpleegkunde) -- Universiteit van Stellenbosch, 1986.Een kopie mikrofiche.Full text to be digitised and attached to bibliographic record

Reply to "Comment on the comparative use of the electron density and its laplacian"

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A comparison of charcoal and stable carbon isotope results for the Caledon River Valley, southern Africa, for the period 13 500 - 5 000 yr BP

The terminal Pleistocene to middle Holocene in the interior of southern Africa is characterized by a warming trend culminating in temperatures similar to or greater than those of today. However, as more refined palaeoenvironmental sequences are produced it becomes increasingly evident that pronounced temperature fluctuations occurred during this period Studies at two contemporaneous archaeological sites in the Caledon River Valley (29?13 'S; 27?28 'E and 29?28'5; 2 7?46 'E) have yielded a proxy climatic history for the period between 13 500 and 5000 yr BP Two independent palaeoenvironmental studies, a charcoal andfaunal stable carbon isotope analysis, were carried out at each site. A comparison of the results of these two analyses indicates that more than one temperature fluctuation occurred during the terminal Pleistocene to the middle Holocene. The record suggests warming to warm temperatures at ca. 12 600-13 000 yr BP (12 925 cal. yr BP), ca. 10 000 yr BP (41 134 cal. yr BP), ca. 8500-8000 yr BP (-9051 cal. yr BP), and ca. 6000-5970 yr BP (-7000 cal. yr BP), while cooler conditions prevailed at ca. 9000-8800 yr BP (10 004 cal. yr BP) and ca. 7300-7000 yr BP (-8000 cal. yr BP). These fluctuations are compared to those recorded elsewhere, in particular those that correspond to the ca. 7300-7000 yr BP event

Intramolecular hydrogen-bond-directed coordination: <I>trans</I>-bis(<I>N</I>-benzoyl-<I>N'</I>-propylthiourea-<I>KS</I>)-diiodoplatinum(II) and <I>trans</I>-bis(<I>N</I>-benzoyl-<I>N'</I>-propylthiourea-<I>KS</I>)dibromoplatinum(II)

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Polymorphic co-crystals from polymorphic co-crystal formers: Competition between carboxylic acid???pyridine and phenol???pyridine hydrogen bond

Please help populate SUNScholar with the full text of SU research output. Also - should you need this item urgently, please send us the details and we will try to get hold of the full text as quick possible. E-mail to [email protected]. Thank you.Journal Articles (subsidised)NatuurwetenskappeChemie & Polimeerwetenska