Measurement of pitch perception as a function of cochlear implant electrode and its effect on speech perception with different frequency allocations.

OBJECTIVE: An experiment was conducted to investigate the possibility that speech perception could be improved for some cochlear implant (CI) users by adjustment of the frequency allocation to the electrodes, following assessment of pitch perception along the electrode array. STUDY SAMPLE: Thirteen adult CI users with MED-EL devices participated in the study. DESIGN: Pitch perception was assessed for individual CI electrode pairs using the Pitch Contour Test (PCT), giving information on pitch discrimination and pitch ranking for adjacent electrodes. Sentence perception in noise was also assessed with ten different frequency allocations, including the default. RESULTS: Pitch perception was found to be poorer for both discrimination and ranking scores at either end of the electrode array. A significant effect of frequency allocation was found for sentence scores [F(4.24,38.2) = 7.14, p < 0.001] and a significant interaction between sentence score and PCT ranking score for basal electrodes was found [F(4.24,38.2) = 2.95, p = 0.03]. Participants with poorer pitch perception at the basal end had poorer scores for some allocations with greater basal shift. CONCLUSIONS: The results suggest that speech perception could be improved for CI users by assessment of pitch perception using the PCT and subsequent adjustment of pitch-related stimulation parameters.

Point of care optical diagnostic technologies for the detection of oral and oropharyngeal squamous cell carcinoma.

BACKGROUND: Despite significant advances in treatment modalities, the 5 year survival rate in oral and oropharyngeal squamous cell carcinoma (SCC) is less than 60%. Clinical examination, white light endoscopy followed by blind biopsies and histopathological analysis remains the gold standard for diagnosis and surveillance. These modalities continue to have a limited diagnostic accuracy of less than 55%. METHODS: Novel optical-based diagnostic methods are promising new technologies for improving both screening and detection of cancer. This review will discuss their role in oral and oropharyngeal cancer detection with particular emphasis on optical imaging in oral and oropharyngeal cancer diagnosis, including the use of surface enhanced Raman spectroscopy, optical coherence tomography, fluorescence diagnosis, confocal laser endomicroscopy, confocal reflectance microscopy and narrow band imaging. RESULTS: Aided by the use of differing wavelengths of light, these methods are capable of detecting physical and biochemical changes that precede and mirror malignant change within tissue. CONCLUSION: Our review of the currently utilized optical diagnostic modalities suggests the possibility of a cost effective, point of care diagnosis that could facilitate early detection, reduce healthcare costs and improve patient survival and quality of life.

Pilot plant study of alternative filter media for rapid gravity filtration.

Sand has been the main filter media used in rapid gravity filtration since its introduction. The dominance of sand has been due to its low cost and availability. Extensive experience has led to sand filters with a dependable and predictable performance. Sand remains the preferred filter medium but usually with a larger sized anthracite capping to reduce the onset of head loss. Other approved filter media are now commercially available and this paper compares sand with recycled glass, Filtralite(®) and slate at pilot scale. The results have reaffirmed the basic importance of particle size on head loss and turbidity performance rather than surface activity or specific surface area. The results did suggest, however, that particle shape and packing exerted a stronger influence on performance than previously acknowledged. These could be used to improve the design and the contribution to sustainability made by rapid gravity filters.

Tuning porosity in macroscopic monolithic metal-organic frameworks for exceptional natural gas storage.

Widespread access to greener energy is required in order to mitigate the effects of climate change. A significant barrier to cleaner natural gas usage lies in the safety/efficiency limitations of storage technology. Despite highly porous metal-organic frameworks (MOFs) demonstrating record-breaking gas-storage capacities, their conventionally powdered morphology renders them non-viable. Traditional powder shaping utilising high pressure or chemical binders collapses porosity or creates low-density structures with reduced volumetric adsorption capacity. Here, we report the engineering of one of the most stable MOFs, Zr-UiO-66, without applying pressure or binders. The process yields centimetre-sized monoliths, displaying high microporosity and bulk density. We report the inclusion of variable, narrow mesopore volumes to the monoliths' macrostructure and use this to optimise the pore-size distribution for gas uptake. The optimised mixed meso/microporous monoliths demonstrate Type II adsorption isotherms to achieve benchmark volumetric working capacities for methane and carbon dioxide. This represents a critical advance in the design of air-stable, conformed MOFs for commercial gas storage.

Induction of vaginal-resident HIV-specific CD8 T cells with mucosal prime-boost immunization.

Tissue-resident memory (TRM) CD8 T cells survey a range of non-lymphoid mucosal tissues where they rapidly mediate clearance of viral infections at the entry portals. Vaccines that establish CD8 TRM cells in the cervicovaginal mucosa hold promise for effective immunity against sexually transmitted HIV. We demonstrate that HIV-specific CD8 TRM cells can be established in the murine vaginal mucosa using a combined intranasal and intravaginal mucosal immunization with recombinant influenza-HIV vectors. Using in situ tetramer immunofluorescence microscopy, we found that this mucosally administered prime-boost immunization also resulted in the durable seeding of CD8 T cells in the frontline vaginal epithelial compartment as opposed to the vaginal submucosa. Upon cognate antigen recognition within the vaginal mucosa, these HIV-specific CD8 TRM cells rapidly initiated a tissue-wide state of immunity. The activation of HIV-specific CD8 TRM cells resulted in the upregulation of endothelial vessel addressin expression and substantial recruitment of both adaptive and innate immune cells in the vaginal mucosa. These findings suggest that the epithelial localization of HIV-specific CD8 TRM cell populations and their capacity to rapidly activate both arms of the immune system could significantly augment frontline defenses against vaginal HIV infection.

Polycyclic aromatic hydrocarbon emissions from clinical waste incineration.

Since the introduction of the Environmental Protection Act in the UK, there are few reports of PAH emissions from clinical waste incinerators (CWIs) operating to improved performance standards. The main aim of this study is to determine PAH emissions from a state-of-the-art CWI focusing on the effects of reactive gases and operating variables on emissions. This was carried out by collection of stack samples over three phases of operation. At stack conditions, most PAHs are predicted to be in the vapour phase. Reactive losses of PAHs were closely correlated by rank with expected reactivities from laboratory studies. Estimates of emissions incorporating sampling losses were derived, although no correlation was found between PAH losses and the modest levels of reactive stack gases. PAH concentrations were one to two orders of magnitude lower than earlier reports from incinerators without effective air pollution control equipment (APCE). The low levels of carbon monoxide recorded were not correlated with any PAHs. This study demonstrates the impact of efficient combustion conditions and APCE on PAH emissions from a CWI.

Effective dosing of topotecan with carboplatin in relapsed ovarian cancer: a phase I/II study.

PURPOSE: This phase I/II study was performed to evaluate the feasibility of administering the topoisomerase inhibitor topotecan in combination with carboplatin. PATIENTS AND METHODS: Topotecan was given as a 30-minute infusion daily for 5 days, with carboplatin given immediately after topotecan on day 5. Treatment was repeated every 21 days. Carboplatin and then topotecan were escalated in sequential cohorts of three to six patients. Four dosage combinations of topotecan days 1 to 5 and carboplatin (day 5) were tested: 0.5 mg/m(2)/d and carboplatin area under the curve (AUC) of 4, topotecan 0.5 mg/m(2)/d and carboplatin AUC of 5, topotecan 0.75 mg/m(2)/d and carboplatin AUC of 5, and topotecan 1.0 mg/m(2)/d and carboplatin AUC of 5. RESULTS: Grade 3 and 4 neutropenia was common at doses of 0.75 mg/m(2)/d and above, but dose-limiting hematologic toxicity occurred in only one patient. The most common reason for dose reduction or delay was failure of myelosuppression to resolve by day 21. Nonhematologic toxicity was generally mild. The maximum-tolerated dose as defined in the protocol was not reached, but topotecan dose escalation was stopped at 1.0 mg/m(2)/d, because delayed neutrophil recovery precluded re-treatment on a 21-day schedule. CONCLUSION: Hematologic toxicity was common but rarely serious, and the combination of topotecan with carboplatin on this schedule was safe and well tolerated. Giving carboplatin to patients after topotecan on day 5, rather than on day 1, allowed dose escalation beyond the levels reported in other studies. The recommended doses for previously treated patients are topotecan 0.75 mg/m(2)/d, days 1 to 5, with carboplatin at an area under the curve (AUC) of 5 following topotecan on day 5. The combination of topotecan 1 mg/m(2)/d, days 1 to 5, followed on day 5 by carboplatin at an AUC of 5, merits further examination in untreated patients.

betaA- and betaC-activin, follistatin, activin receptor mRNA and betaC-activin peptide expression during rat liver regeneration.

The mRNA expression of two activin growth factor subunits (betaA- and betaC-activin), activin receptor subunits (ActRIIA, ActRIIB) and the activin-binding protein follistatin, and peptide expression of betaA-activin and betaC-activin subunits, were examined in regenerating rat liver after partial hepatectomy (PHx). Liver samples were collected from adult, male Sprague-Dawley rats, 12-240 h (n=3-5 rats per time point) after PHx or from sham-operated controls at the same time points. Hepatocyte mitosis and apoptosis were assessed histologically and by in situ cell death detection. RT and PCR were used to assess relative gene expression. betaA- and betaC-activin peptide immunoreactivity was assessed in liver and serum samples by western blotting, whereas cellular expression was investigated by immunohistochemistry, using specific monoclonal antibodies. betaA- and betaC-activin mRNA dropped to < 50% of sham control values 12 h after PHx and remained at this level until 168 h post-PHx, when betaA-activin expression increased to three times sham control values and betaC-activin mRNA returned to pre-PHx levels. A peak in follistatin expression was observed 24-48 h post-PHx, coincident with an increase in hepatocyte mitosis. No changes were observed in ActRIIA mRNA, whereas ActRIIB expression paralleled that of betaA-activin mRNA. betaC-activin immunoreactive homo- and heterodimers were observed in regenerating liver and serum. Mitotic hepatocytes frequently contained betaC-activin immunoreactivity, whereas apoptotic hepatocytes were often immunoreactive for betaA-activin. We conclude that betaA- and betaC-activin subunit proteins are autocrine growth regulators in regenerating liver and when expressed independently lead to hepatocyte apoptosis or mitosis in a subset of hepatocytes.

Hydrothermal carbonisation of sewage sludge: effect of process conditions on product characteristics and methane production.

Hydrothermal carbonisation of primary sewage sludge was carried out using a batch reactor. The effect of temperature and reaction time on the characteristics of solid (hydrochar), liquid and gas products, and the conditions leading to optimal hydrochar characteristics were investigated. The amount of carbon retained in hydrochars decreased as temperature and time increased with carbon retentions of 64-77% at 140 and 160°C, and 50-62% at 180 and 200°C. Increasing temperature and treatment time increased the energy content of the hydrochar from 17 to 19 MJ/kg but reduced its energy yield from 88% to 68%. Maillard reaction products were identified in the liquid fractions following carbonisations at 180 and 200°C. Theoretical estimates of the methane yields resulting from the anaerobic digestion of the liquid by-products are also presented and optimal reaction conditions to maximise these identified.

Association analysis of beta2 adrenoceptor polymorphisms with hypertension in a Black African population.

OBJECTIVE: To determine whether or not beta2 adrenoceptor polymorphism is a risk factor for the development of hypertension in a Black South African population. BACKGROUND: Attenuated vasodilator responses to endogenous catecholamines may contribute to the aetiology of hypertension. Downregulation of beta2 adrenoreceptors (beta2AR) following stimulation with agonists is determined in part by variation at the beta2AR gene locus. The Glu27 beta2AR genotype results in attenuated downregulation compared with the wild-type Gln27 receptor, whereas Gly16 exhibits enhanced down-regulation compared to Arg16. Possible racial differences in the prevalence of the beta2AR polymorphisms may be an explanation for the blunted responses to isoprenaline and the increased prevalence of hypertension in Black African populations. METHODS: One hundred and ninety-two unrelated hypertensives and 123 normotensives of Black South African origin were studied. Hypertensives were recruited from hospital hypertension clinics in the province of Gauteng and if on treatment, had a 2-4 week washout period before 24-h ambulatory blood pressure assessment Normotensive controls were recruited from the same community. RESULTS: There was no significant association between either the Arg-Gly16 polymorphism or the Gln-Glu27 polymorphism and hypertension status. Furthermore, in the hypertensives, no significant association was seen between beta2AR genotype at either site and clinical blood pressure, 24-h blood pressure or left ventricular mass. A significant association was seen between Arg16 homozygotes and lower body mass index in hypertensives (P = 0.007) although this was not a primary end point. Interestingly, the Glu27 polymorphism was much rarer in this population (allelic frequency 17%) compared to a Caucasian population. CONCLUSION: These data suggest that beta2AR polymorphism is not a risk factor for hypertension per se in this defined population. The possibility that the decreased prevalence of Glu27 in black South African populations explains blunted vasodilator responses to isoprenaline requires further study.

Successful hepatic grafting after partial portal vein ligation in the rat: complete reversal of hemodynamic abnormalities.

BACKGROUND: Partial portal vein ligation (PPVL) is an established approach in the study of prehepatic portal hypertension in animals. The effect of orthotopic liver transplants (OLT) on hemodynamics in PPVL animals has not been investigated to date. The aim of this study was to develop a model of OLT in PPVL rats and to investigate its hemodynamic consequences. METHODS: Three groups of male Lewis rats were investigated (1) control animals (n=7), (2) PPVL (n=9), and (3) PPVL/OLT (n=16). Three weeks after PPVL, 9 animals were taken for hemodynamic measurements. OLT was performed in the remaining 16 PPVL rats (PPVL/OLT), and, 4 weeks later, hemodynamic measurements were made. Blood biochemical analysis was performed at different time points in all 3 groups. RESULTS: The PPVL animals presented with hyperdynamic systemic circulation, extensive collateral vascularization in the hilar region, and portal-systemic shunting (portal systemic shunting; 35.3+/-5.5%). In the PPVL/OLT group, 15 rats survived for 4 weeks (survival: 93.8%, 15 of 16). Of these PPVL/OLT rats, 3 died during the blood sampling protocol. In 3 PPVL/OLT rats, abnormal liver function and histology were found and deranged systemic and hepatic hemodynamics persisted after OLT. In the remaining 9 PPVL/OLT rats, systemic and hepatic hemodynamics had returned to normal at 4 weeks and portal systemic shunting was markedly reduced (2.5+/-0.9%). Liver function was in the normal range. CONCLUSIONS: (1) The possibility of performing OLT in PPVL rats with a high rate of survival has been confirmed. (2) In the majority of cases, complete reversal of hemodynamic abnormalities in the PPVL animals occurs after OLT (3). PPVL/OLT represents a new and important model in OLT research.

Endotelin ETA and ETB receptor antagonism during cold preservation in renal transplantation.

BACKGROUND: In this study, we investigated the effects of selective endothelin (ET) receptor antagonism during different periods of cold ischemia on glomerular and tubular function and long-term survival in renal transplantation. METHODS: Left renal transplantation was performed in Lewis rats after 2 hr of cold ischemia without (n=8) and with (n=6) ETA receptor antagonism and after 16 hr of cold ischemia without treatment (n=6), with ETA receptor antagonism (n=8) and with ETB receptor antagonism (n=6). A control group (n=8) underwent right nephrectomy and left renal denervation. The ETA and ETB receptor antagonists (BQ-610 and A-192621, respectively) were added to the preservation solution (EuroCollins). After transplantation, renal glomerular and tubular functions were monitored for up to 60 days or death. RESULTS: All animals in the control and 2-hr groups survived the follow-up protocol, with early postoperative recovery of glomerular and tubular function while the entire untreated 16-hr group died between day 3-6 postoperatively. BQ-610 treatment had no measurable effect on the renal function in the 2-hr group, however, it improved glomerular and tubular functions and led to 50% long-term survival (60 days) in the 16-hr group. A-192621 treatment had no effect on long-term survival or renal parameters. CONCLUSION: ETA receptor antagonism had protective renal effects after prolonged ischemic preservation in renal transplantation while ETB receptor antagonism had not.

Effect of ischemia-reperfusion injury on the microcirculation of the steatotic liver of the Zucker rat.

BACKGROUND: Much discussion has been focused on the use of steatotic livers for transplantation due to the prevalence of steatosis in the potential donor liver pool (1). The aim of this study was to investigate the possibility that the microcirculation of steatotic liver is more sensitive to the ischemia-reperfusion (IR) injury than normal liver. METHODS: The left liver lobe of obese (n=9) and lean Zucker rats (n=9) were subjected to 40 min of warm ischemia followed by 60 min of reperfusion. Fluorescent probes rhodamine 123 (Rh123), bisbenzimide (Bis), and rhodamine 6G (Rh6G) were administered for the identification by intravital fluorescence microscopy (IVFM) of mitochondrial membrane potential, hepatocyte nuclei and leukocytes, respectively before hepatic ischemia and at 15, 30, 45, and 60 min after reperfusion. Blood samples were obtained before and after 60 min of reperfusion. Liver tissue was taken at the end of experiment for histological analysis. RESULTS: The liver of the obese rats showed prominent macro- and microvesicular fatty changes (MAFC and MIFC) and hepatocyte swelling. Under IVFM, the obese animals had significantly wider hepatic cords (23.1+/-0.8 microm) than the lean ones (15.9+/-0.5 microm) (P<0.01), whereas no significant difference in sinusoidal diameters was noted. The number of functional sinusoids significantly decreased after 30 min of reperfusion in both groups but no significant change was noted in the nucleus count throughout the experiment. Rh123 fluorescence intensity dropped significantly in the obese group after 60 min of reperfusion but not in the lean rats. Leukocyte adherence showed a significant rise after reperfusion in both groups. Plasma AST and ALT levels were 40- and 24-fold higher respectively for the obese animals after IR compared with their preischemic values, whereas the corresponding increase were 4.2- and 3.4-fold for the lean animals, respectively. CONCLUSIONS: Our results indicate that the liver of the obese Zucker rat is steatotic and presents with an abnormal microcirculation manifested by a reduced sinusoidal density. IR led to significantly greater hepatic injury in the steatotic than in the normal liver. This injury was accompanied by a significant reduction in the functional sinusoidal density and mitochondrial membrane potential as assessed by Rh123-associated fluorescence in the steatotic liver. In conclusion, the increased sensitivity of the steatotic liver to IR injury would appear to involve both alterations in blood flow in the microcirculation and to cellular changes.

Effect of orthotopic liver transplantation and chemical denervation of the liver on the activities of hepatic monoamine oxidase and catechol-O-methyltransferase.

The denervation of some tissue is associated with a fall in the activities of monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). Here we report on the effect of orthotopic liver transplantation and chemical denervation of the liver on the enzymes. Liver transplantation was performed on Lewis rats (n = 7). Denervation (n = 8) was by intraportal injection of 6-hydroxydopamine (75 mg/kg). A control group (n = 8) was also included. The norepinephrine content of the transplanted and denervated livers was reduced by greater than 99% (P < 0.001) and 95% (P < 0.001), respectively. The activity of hepatic COMT (substrate: catechol [5 mM] was not affected by transplantation or denervation. The activity of MAO with 0.1 mM 5-hydroxytryptamine (5-HT) (substrate for MAO-A) and with 0.01 mM 2-phenylethylamine (substrate for MAO-B) were not affected by denervation. In the transplanted liver, the activity of MAO with 5-HT and 2-phenylethylamine was increased by 26% (P < 0.05) and by 53% (P < 0.001), respectively. The ratios of the activities of the A to B forms of MAO (approximately 70% A to 30% B) was not affected by either procedure. Enzyme sensitivity for MAO inhibitors clorgyline and deprenyl were not significantly altered by transplantation. The concentration of plasma norepinephrine in the transplantation group was significantly lower than either the control (P < 0.001) or denervation groups (P < 0.05). We conclude from our results that the metabolism of circulating catecholamines by the liver is unlikely to be impaired after liver transplantation.

Identification of novel polymorphisms within the promoter region of the human beta2 adrenergic receptor gene.

By screening the 1470 bp 5' to the start codon of the human beta2 adrenergic receptor gene, we have identified a total of eight polymorphisms (-20 T-->C, -47 T-->C, -367 T-->C, -468 C-->G, -654 G-->A, -1023 G-->A, -1343 A-->G and -1429 T-->A c.f. beta2 adrenergic receptor start codon). Transient transfection of 5' flanking deletion luciferase reporter constructs demonstrated the majority of activity of the human beta2 adrenergic gene 5' flanking region to be present within a 549 bp fragment immediately upstream from the start codon. Because of linkage disequilibrium, some combinations of polymorphisms were particularly frequent. We transiently transfected COS-7 cells with luciferase constructs under the control of the 549 bp of 5' flanking DNA containing the two most frequent extended haplotypes in this region. Luciferase activity was significantly reduced in cells transfected with the 'mutant' construct (-20C, -47C, -367C, -468G) c.f. the 'wild-type' construct (-20T, -47T, -367T, -468C). These data suggest that polymorphisms have the potential to alter human beta2 adrenergic receptor gene expression.

Randomized trial of duodenum-preserving pancreatic head resection versus pylorus-preserving Whipple in chronic pancreatitis.

BACKGROUND: In about 30% of patients, chronic pancreatitis leads to an inflammatory enlargement of the pancreatic head with subsequent obstruction of the pancreatic duct, common bile duct, and duodenum. METHODS: In a prospective, randomized controlled trial, we compared duodenum-preserving pancreatic head resection (DPPHR) with pylorus-preserving Whipple (PPW) operation to define the advantages of each operation with regard to (1) postoperative complications, (2) glucose tolerance and induction of diabetes mellitus, and (3) postoperative pain and quality of life up to 6 months after operation for chronic pancreatitis. RESULTS: The two study groups of 20 patients were both well balanced with regard to sex, age, history of chronic pancreatitis, and indication for surgery. Postoperative mortality was zero. After duodenum-preserving and pylorus-preserving resection, morbidity was 15% and 20%, respectively. After 6 months, patients who underwent the duodenum-preserving resection had less pain, greater weight gain, a better glucose tolerance, and a higher insulin secretion capacity. CONCLUSION: The DPPHR compares favorably with the standard PPW operation and should be considered as an alternative procedure in the treatment of chronic pancreatitis.

Do corticosteroids induce apoptosis in nasal polyp inflammatory cells? In vivo and in vitro studies.

OBJECTIVE/HYPOTHESIS: Corticosteroids are an effective treatment for nasal polyposis. The exact mechanism of action is not certain. Recent research demonstrates that apoptosis (programmed cell death) in inflammatory cells is an important factor in the resolution of inflammation, and apoptosis is induced in eosinophils in cell culture with steroids. We hypothesized that inflammatory cell apoptosis is a key feature of regression of nasal polyps on exposure to steroids and examined this hypothesis in vivo and in vitro. METHODS: A double-blind, placebo-controlled pilot study of fluticasone propionate aqueous nasal spray (FPANS) in nasal polyposis in humans in vivo was undertaken, and the effect of treatment on indices of cell death and proliferation measured. In addition, explants of nasal polyp tissue were maintained in vitro in short-term tissue culture with dexamethasone at increasing doses (0.1-50 micromol) over varying time intervals and then analyzed for similar indices of proliferation and cell death. RESULTS: Apart from a marginal increase in apoptotic:mitotic ratio in epithelium, little difference between the effect of FPANS and placebo was demonstrated in vivo. However, in vitro, apoptotic index was significantly increased in the stromal layers in relation to time of incubation (P = .0169), and a significant dose-response relationship was demonstrated at 24 hours between stromal cell apoptosis and dexamethasone concentration (P = .001). Eosinophil apoptosis was confirmed by in situ end labeling and transmission electron microscopy. No steroid or time effect on epithelial cells was demonstrated in vitro. CONCLUSION: Corticosteroids induce apoptosis in inflammatory cells in human nasal polyps in vitro. This is not reflected by a similar response to FPANS at 14 days in vivo, but may still play a part in regression of polyps with other forms of administration or at other time points.

Methods for Determining ß(2)-Adrenoreceptor Genotype.

Polymorphisms of the ß(2)-adrenoceptor (ß(2)AR) have been the focus of much interest as part of the search to elucidate the genetic basis of asthma and allergic disease. More recently, these polymorphisms have also been implicated in the genetic etiology of essential hypertension (1,2) and obesity (3,4). This chapter describes in detail the method of allele-specific-oligonucleotide hybridization (ASO), a technique that has been used extensively by the authors' group to determine ß(2)AR genotype. This method should prove useful not only to those intending to analyze ß(2)AR polymorphisms, but also for the analysis of other candidate genes, given that this technique can be adapted and applied to any known single-base mutation.

Anaerobic/aerobic treatment of coloured textile effluents using sequencing batch reactors.

Conventional biological wastewater treatment plants do not easily degrade the dyes and polyvinyl alcohols (PVOH) in textile effluents. Results are reported on the possible advantages of anaerobic/aerobic cometabolism in sequenced redox reactors. A six phase anaerobic/aerobic sequencing laboratory scale batch reactor was developed to treat a synthetic textile effluent. The wastewater included PVOH from desizing and an azo dye (Remazol Black). The reactor removed 66% of the applied total organic carbon (load F: M 0.15) compared to 76% from a control reactor without dye. Colour removal was 94% but dye metabolites caused reactor instability. Aromatic amines from the anaerobic breakdown of the azo dyes were not completely mineralised by the aerobic phase. Breakdown of PVOH by the reactor (20-30%) was not as good as previous reports with entirely aerobic cultures. The anaerobic cultures were able to tolerate the oxygen and methane continued to be produced but there was a deterioration in settlement.

Polycyclic aromatic hydrocarbons in solid residues from waste incineration.

Polycyclic aromatic hydrocarbons (PAH) levels in solid residues from clinical waste incineration were measured using HPLC with fluorescence detection. PAH mass emission rates and emission rates as a function of waste burned are also reported. For bottom ash, PAH levels and physical properties were found to be quite consistent. Levels of high molecular mass PAHs were comparable to levels previously reported in the literature when adjusted for differences in sample preparation techniques. However, levels of low molecular mass PAHs were considerably elevated in this study. Possible reasons for this finding include the composition of the waste, combustion conditions and methods of sample preparation. In contrast, no PAHs were found in fly ash, an unexpected finding which is probably attributable to matrix effects resulting from a surfeit of lime in the fly ash. Factors effecting the partitioning of PAHs and their environmental fate are also discussed.