Characterization of impurity effects in zinc electrowinning from industrial acid sulphate electrolyte

The individual effects of 15 impurities and their interaction with glue on zinc electrowinning from industrial acid sulphate electrolyte were characterized in terms of deposit morphology and preferred deposit orientation and in terms of current efficiency and zinc deposition polarization behaviour. The current efficiency decreased in a cyclical manner with increasing atomic number of the impurity element in each period of the periodic table. This decrease in current efficiency can be correlated to a corresponding increase in the rate of hydrogen evolution on the impurity metal. The various impurities produced four distinct zinc deposit morphologies and orientations and also produced characteristic changes in the cyclic voltammograms for the zinc deposition.     

Relation between oesophageal acid exposure and healing of oesophagitis with omeprazole in patients with severe reflux oesophagitis

BACKGROUND/AIMS: Reducing oesophageal acid exposure by suppressing acid secretion with omeprazole is highly effective in healing reflux oesophagitis. Some patients with severe oesophagitis, fail to heal and whether this results from inadequate acid suppression or other factors is unclear. The aim of this study, was to investigate the relation between oesophageal acid exposure and healing in patients with severe reflux oesophagitis treated with omeprazole. METHODS: Sixty one patients with grade 3 or 4 ulcerative oesophagitis were treated for eight weeks with omeprazole 20 mg every morning. Those patients unhealed at eight weeks were treated with 40 mg every morning for a further eight weeks. Endoscopy and 24 hour oesophageal pH monitoring were performed before treatment and at the end of each treatment phase while receiving treatment. RESULTS: Thirty per cent of patients failed to heal with the 20 mg dose. Unhealed patients had greater total 24 hour oesophageal acid exposure before treatment, and while receiving treatment also had greater acid exposure and a smaller reduction in acid exposure than did patients who healed. Forty seven per cent of the unhealed patients also failed to heal with the 40 mg dose. These patients had similar levels of acid exposure before treatment to those who healed, but had greater acid exposure while receiving treatment, particularly at night when supine. CONCLUSIONS: Patients with severe ulcerative oesophagitis who are refractory to omeprazole have greater oesophageal acid exposure while receiving treatment than responding patients. This is due to a reduced responsiveness to acid suppression, and is likely to be an important factor underlying the failure of the oesophagitis to heal.     

The effects of saponin,antimony and glue on zinc electrowinning from Kidd Creek electrolyte

The effects of Saponin alone and in combination with antimony and glue on zinc deposition current efficiency and polarization and on the morphology and orientation of 6h and 24h zinc deposits electrowon at 500 A m^–2 and 38°C from Kidd Creek zinc electrolyte were determined. Saponin, at concentrations to 100mgl^–1, was weakly polarizing, changed the preferred deposit orientation from basal to intermediate and decreased the current efficiency. At optimum glue + antimony levels, Saponin concentrations 5mgl^–1 resulted in an increase in zinc deposition current efficiency and consistently gave either a <114><112><103><102><101> or a <101><112> preferred deposit orientation depending on the antimony + glue combination used. Tests run for 24h for selected combinations of Saponin, antimony and glue confirmed the results obtained for the 6h studies.     

Screening for genetic haemochromatosis in a rheumatology clinic

Vertebral osteochondrosis is one of the most prevalent diseases of man. The principal method for its diagnosis is x-ray examination that shows the major changes in the spine and, only indirectly, in the cord. The details are revealed by computer-aided tomography. Magnetic resonance tomography (MRT) is the most informative for the purpose, for it permits the assessment of the fine shifts in the brain and adjacent tissues, as well as the status of the vertebral disks by a noninvasive method. A total of 453 patients with various diseases of the spine and cord were examined with the TOMIKON BMT 1100 T tomographer with different pulsed sequences SPIN-echo and GRADIENT-echo, that helped differentiate between the lesions with similar clinical symptoms, such as vertebral disk hernias, extramedullary tumors, cicatricial deformations compressing the dural space and the cord, costal changes, etc. Traumatic injuries of the spinal cord, compressions of the cord with subsequent posttraumatic syringomyelia could be well differentiated. These results evidence the efficacy of MRT as a method for the diagnosis of vertebro-neurologic diseases, particularly those lacking clear-cut symptoms. MRT advantages are the possibility of imaging in many projections and visualisation of soft-tissue structures without resorting to invasive methods.     

Superconvergent derivatives: A Taylor series analysis

An analysis, based on the use of Taylor series expansions, is developed to determine accuracy estimates for derivatives in one and two dimensions computed by differentiation of a finite-element interpolant or approximation. The analysis clarifies some issues concerning special points at which the derivatives are believed to be exceptionally accurate with higher convergence rates (superconvergence). Moreover, it leads directly to a class of post-processing strategies for the derivatives and offers a more direct constructive approach to the subject.     

No association between the serotonin transporter-linked promoter region polymorphism and either schizophrenia or density of the serotonin transporter in human hippocampus

BACKGROUND: Allelic association case-control analysis of a deletion/insertion polymorphism in the serotonin transporter-linked polymorphic region (5-HTTLPR) has suggested associations with unipolar disorder, bipolar disorder, depression, and Alzheimer's disease. Moreover, the heterozygous long form of the 5-HTTLPR has been associated with increased levels of mRNA for the serotonin transporter (5-HTT) and increased serotonin uptake in lymphoblastic cell lines. This study attempts to determine whether there is an association between 5-HTTLPR genotype and schizophrenia or the binding of [3H]paroxetine to the human hippocampal 5-HTT. MATERIALS AND METHODS: DNA from the cerebellum from 58 schizophrenic and 62 control subjects was used to genotype the 5-HTTLPR. In addition, the relationship between 5-HTTLPR genotype and the affinity and density of [3H]paroxetine binding to the hippocampal 5-HTT was assessed. RESULTS: There were no associations between 5-HTTLPR allotype or genotype and/or the parameters of [3H]paroxetine binding to the hippocampal 5-HTT. CONCLUSIONS: Our data suggest that 5-HTTLPR genotype neither confers an increased susceptibility for schizophrenia nor dictates the expression of the 5-HTT in the human hippocampus.     

Factors affecting the electrochemical behaviour of copper anodes under simulated electrorefining conditions

Cyclic voltammetry (CV) was used to characterize the behaviour of copper anodes during electrorefining. The method involved cycling the anode potential at a rate of 2 mV s^–1 between the open circuit potential of –0.35 V and 0.0 V vs mercury/mercurous sulphate (MSE) reference electrode. Reproducible electrochemical characteristics for pure copper anodes of different shapes, sizes and configurations (vertical vs horizontal) were determined. Passivation time measurements indicated a strong correlation between the CV profile and the ease of anode passivation. The size, shape and geometrical configuration of the anode impact significantly on the electrochemical dissolution and passivation of pure copper. An IBM compatible computer equipped with a data acquisition board was used to acquire, examine, compare, and catalogue the electrochemical data which were presented in the form of a potential-current-time spectrum rather than a conventional cyclic voltammogram. This format enhanced the clarity and readability of the results.     

The energetics of walking on sand and grass at various speeds

This study investigated the energetics of walking on sand and grass. Fourteen adult males, participated in the study. Participants had a mean age of 34.6 years old, 72.6 kg in mass and 172.5 cm in stature, who walked at 3, 4, 5, 6 and 7 km per h on sand and grass surfaces. Physiological measures included heart rate, O(2) uptake, CO(2) exhalation, ventilation and relative O(2) uptake using a MetaMax Ergospirometer. Speed was controlled in a methodology similar to the 'Multistage 20-m Shuttle Run Test'. Data were collected during physiological steady rate at each determined speed. A minimum of 2 h rest was enforced between randomized conditions. Results indicate that there was a significant increase (p < 0.01) in all measured physiological indices indicative of energy expenditure when walking on sand compared to grass at 3-7 km per h, with the greatest disparity between the surfaces (ratio = 1.63) in relative O(2) consumption at 5 km per h.