Behaviour of persistent organochlorine micropollutants during primary sedimentation of waste water

The removal of polychlorinated biphenyls and the organochlorine insecticides gamma-HCH, aldrin, dieldrin and endrin during primary sedimentation of raw sewage has been studied using a pilot plant facility. A matrix of sixteen experiments was performed, where the pilot plant was operated at four different hydraulic loadings with four different influent suspended solids loadings. Significant removals of micropollutants into the primary sludge were observed, although no particular relationship with the removal of suspended solids was evident. It is concluded that a proportion of the organic microcontaminants present in raw sewage were associated with non-settleable solids and were also in the dissolved form. The significance of the behaviour of organochlorine micropollutants in waste water treatment processes and the hydrological cycle are discussed in the context of water re-use operations.     

Mutant huntingtin expression in clonal striatal cells: dissociation of inclusion formation and neuronal survival by caspase inhibition

Neuronal intranuclear inclusions are found in the brains of patients with Huntington's disease and form from the polyglutamine-expanded N-terminal region of mutant huntingtin. To explore the properties of inclusions and their involvement in cell death, mouse clonal striatal cells were transiently transfected with truncated and full-length human wild-type and mutant huntingtin cDNAs. Both normal and mutant proteins localized in the cytoplasm, and infrequently, in dispersed and perinuclear vacuoles. Only mutant huntingtin formed nuclear and cytoplasmic inclusions, which increased with polyglutamine expansion and with time after transfection. Nuclear inclusions contained primarily cleaved N-terminal products, whereas cytoplasmic inclusions contained cleaved and larger intact proteins. Cells with wild-type or mutant protein had distinct apoptotic features (membrane blebbing, shrinkage, cellular fragmentation), but those with mutant huntingtin generated the most cell fragments (apoptotic bodies). The caspase inhibitor Z-VAD-FMK significantly increased cell survival but did not diminish nuclear and cytoplasmic inclusions. In contrast, Z-DEVD-FMK significantly reduced nuclear and cytoplasmic inclusions but did not increase survival. A series of N-terminal products was formed from truncated normal and mutant proteins and from full-length mutant huntingtin but not from full-length wild-type huntingtin. One prominent N-terminal product was blocked by Z-VAD-FMK. In summary, the formation of inclusions in clonal striatal cells corresponds to that seen in the HD brain and is separable from events that regulate cell death. N-terminal cleavage may be linked to mutant huntingtin's role in cell death.     

Laboratory evaluation of CDDC as a wood preservative for red oak (Quercus rubra) and red maple (Acer rubrum)

) and red maple (Acer rubrum) cubes were pressure treated with copper ethanolamine followed by sodium dimethyldithiocarbamate (SDDC) with elemental copper retention levels varying from 0.8 kg/m³ to 8 kg/m³. The decay resistance was determined using a laboratory soil block test with pure fungus culture according to modified AWPA standard E10-91. A 4.0 kg/m³ elemental copper retention was sufficient to protect treated samples against Gleoephyllum trabeum, Pleurotus ostreatus, Trametes versicolor, Irpex lacteus, and Chaetomium globosum. But higher elemental copper retention (4.5 to 5 kg/m³) was needed for protection against the copper tolerant brown rot Poria placenta.     

Continuous online monitoring of ionic dialysance allows modification of delivered hemodialysis treatment time

Considerable intrinsic intrapatient variability influences the actual delivery of Kt/V. The aim of this study is to examine the feasibility of using continuous online assessment of ionic dialysance measurements (Kt/V(ID)) to allow dialysis sessions to be altered on an individual basis. Ten well-established chronic hemodialysis (HD) patients without significant residual renal function were studied (mean age 65+/-4.3 [38-81] years, mean length of time on dialysis 66+/-18 [14-189] months). These patients had all been receiving thrice-weekly 4-hr dialysis using Integra dialysis monitors. Dialysis monitors were equipped with Diascan modules permitting measurement of Kt/V(ID). Predicted treatment time required to achieve a Kt/V(ID) > or = 1.1 (equivalent to a urea-based method of 1.2) was calculated from the delivered Kt/V(ID) at 60 and 120 min. Treatment time was reprogrammed at 2 hr (ensuring all planned ultrafiltration would be accommodated into the new modified session duration). Owing to practical issues, and to avoid excessively short dialysis times, these changes were censored at no more than+/-10% of the usual 240-min treatment time (210-265 min). Data were collected from a total of 50 dialysis sessions. Almost all sessions (47/50) required modification of the standard treatment time: 13/50 sessions were lengthened and 34/50 shortened (mean length of session 232.2+/-2.5 [210-265] min). A Kt/V(ID) of > or = 1.1 was achieved in 39/50 sessions. The difference in mean urea-based Kt/V poststudy (1.3+/-0.05 [1.1-1.6]) and mean achieved Kt/V(ID) (1.16+/-0.02 [0.7-1.37]) was significant (p = 0.002). The use of individualized variable dialysis treatment time using online ionic dialysance measurements of Kt/V(ID) appears both practicable and effective at ensuring consistently delivered adequate dialysis.     

Simultaneous line center and linewidth measurement using dual frequency modulation spectroscopy

We propose a method to simultaneously measure the center frequency of a spectral feature and the frequency linewidth of the feature. The method relies on dual frequency modulation of a carrier frequency, which probes the spectral feature, and phase sensitive detection of the transmitted signal at the two modulation frequencies. The detected signals provide two servo-stabilization signals for frequency control of the carrier frequency to the resonance line center and one of the modulation frequencies to the resonance linewidth.     

Determinants of survival in patients receiving dialysis in Libya

Maintenance dialysis is associated with reduced survival when compared with the general population. In Libya, information about outcomes on dialysis is scarce. This study, therefore, aimed to provide the first comprehensive analysis of survival in Libyan dialysis patients. This prospective multicenter study included all patients in Libya who had been receiving dialysis for >90 days in June 2009. Sociodemographic and clinical data were collected upon enrolment and survival status after 1 year was determined. Two thousand two hundred seventy‐three patients in 38 dialysis centers were followed up for 1 year. The majority were receiving hemodialysis (98.8%). Sixty‐seven patients were censored due to renal transplantation, and 46 patients were lost to follow‐up. Thus, 2159 patients were followed up for 1 year. Four hundred fifty‐eight deaths occurred, (crude annual mortality rate of 21.2%). Of these, 31% were due to ischemic heart disease, 16% cerebrovascular accidents, and 16% due to infection. Annual mortality rate was 0% to 70% in different dialysis centers. Best survival was in age group 25 to 34 years. Binary logistic regression analysis identified age at onset of dialysis, physical dependency, diabetes, and predialysis urea as independent determinants of increased mortality. Patients receiving dialysis in Libya have a crude 1‐year mortality rate similar to most developed countries, but the mean age of the dialysis population is much lower, and this outcome is thus relatively poor. As in most countries, cardiovascular disease and infection were the most common causes of death. Variation in mortality rates between different centers suggests that survival could be improved by promoting standardization of best practice.     

Optical properties of an octadecylphosphonic acid self-assembled monolayer on a silicon wafer

We report a study of a full-coverage octadecylphosphonic acid (OPA or ODPA) self-assembled monolayer (SAM) spin-coated on the native oxide layer (SiO₂) of a single crystalline silicon (c-Si) wafer using spectroscopic ellipsometry (SE) and reflectometry (SR). The OPA SAM showed characteristics of being a dielectric film in visible range and becoming absorbing in deep-UV range. By assuming an optical stack model of OPA/SiO₂/c-Si for the OPA monolayer system and adopting the parameterized Tauc-Lorentz dispersion model, we obtained an excellent fit of the model to the SE and SR data, from which dispersion of optical functions as well as thickness of the OPA film were deduced. The OPA film thickness measured by atomic force microscopy (AFM) on partial coverage OPA samples was used as the initial trial film thickness in the fitting processes. The deduced OPA film thickness from SE and SR data fitting was in good agreement with that obtained by AFM.