High selectivity microporous silica membranes for lactic acid dehydration

Lactic acid (LA) has significant market potential for many industries including food, cosmetics, pharmaceuticals, medical and biodegradable materials. Production of LA usually begins with the fermentation of glucose but subsequent stages for the enrichment of lactic acid are complex and energy intensive and could be minimised using water selective membrane technology. In this work, we trialled a highly selective hydrostable carbonised template molecular sieve silica (CTMSS) membrane for the dehydration of a 15 vol% aqueous lactic acid solution with 0.1 vol% glucose. CTMSS membrane films were developed by dip-coating ceramic substrates with silica sols made using the acid catalysed sol-gel process. Permeation was performed by feeding LA/glucose solution to the membrane cell at 18°C in a standard pervaporation setup. The membrane showed selective transport of water from the aqueous feed to the permeate while glucose was not detected. CTMSS membrane permeate flux stabilised at 0.2 kg.m-2.hr-1 in 3.9 hours, and reduced LA to lower than 0.2 vol%. Flux through the CTMSS micropores was activated, displaying increased initial flux to 1.58 kg.m-2.hr-1 at 60°C. To enrich a 1 l.min-1 stream to 85% LA in a single stage, a minimum membrane area of 324 m2 would be required at 18°C. Increased operating temperature to 80°C significantly reduced this area to 24 m2 but LA levels in the permeate stream increased to 0.5 vol%. The highly selective CTMSS membrane technology is an ideal candidate for LA purification. CTMSS membrane systems operate stably in aqueous systems leading to potential cost reductions in LA processing for future markets.

Data partitioning for parallel spatial join processing

The cost of spatial join processing can be very high because of the large sizes of spatial objects and the computation-intensive spatial operations. While parallel processing seems a natural solution to this problem, it is not clear how spatial data can be partitioned for this purpose. Various spatial data partitioning methods are examined in this paper. A framework combining the data-partitioning techniques used by most parallel join algorithms in relational databases and the filter-and-refine strategy for spatial operation processing is proposed for parallel spatial join processing. Object duplication caused by multi-assignment in spatial data partitioning can result in extra CPU cost as well as extra communication cost. We find that the key to overcome this problem is to preserve spatial locality in task decomposition. We show in this paper that a near-optimal speedup can be achieved for parallel spatial join processing using our new algorithms.

Anthropometric-based selection and sprint kayak training in children

A 12 week kayak training programme was evaluated in children who either had or did not have the anthropometric characteristics identified as being unique to senior elite sprint kayakers. Altogether, 234 male and female school children were screened to select 10 children with and 10 children without the identified key anthropometric characteristics. Before and after training, the children completed an all-out 2 min kayak ergometer simulation test; measures of oxygen consumption, plasma lactate and total work accomplished were recorded. In addition, a 500 m time trial was performed at weeks 3 and 12. The coaches were unaware which 20 children possessed those anthropometric characteristics deemed to favour development of kayak ability. All children improved in both the 2 min ergometer simulation test and 500 m time trial. However, boys who were selected according to favourable anthropometric characteristics showed greater improvement than those without such characteristics in the 2 min ergometer test only. In summary, in a small group of children selected according to anthropometric data unique to elite adult kayakers, 12 weeks of intensive kayak training did not influence the rate of improvement of on-water sprint kayak performance.

Economic incentives for farmers in the Philippine uplands to adopt hedgerow intercropping

Land degradation in the Philippine uplands is severe and widespread. Most upland areas are steep, and intense rainfall on soils disturbed by intensive agriculture can produce high rates of soil loss. This has serious implications for the economic welfare of a growing upland population with few feasible livelihood alternatives. Hedgerow intercropping can greatly reduce soil loss from annual cropping systems and has been considered an appropriate technology for soil conservation research and extension in the Philippine uplands. However; adoption of hedgerow intercropping has been sporadic and transient, rarely continuing once external support has been withdrawn. The objective of this paper is to investigate the economic incentives for farmers in the Philippine uplands to adopt hedgerow intercropping relative to traditional open-field maize farming. Cost-benefit analysis is used to compare the economic viability of hedgerow intercropping, as it has been promoted to upland farmers, with the viability of traditional methods of open-field farming. The APSIM and SCUAF models were used to predict the effect of soil erosion on maize yields from open-field farming and hedgerow intercropping. The results indicate that there have been strong economic incentives for farmers with limited planning horizons to reject hedgerow intercropping because the benefits of sustained yields are not realized rapidly enough to compensate for high establishment costs. Alternative forms of hedgerow intercropping such as natural vegetation and grass strips reduce establishment and maintenance costs and are therefore more economically attractive to farmers than hedgerow intercropping with shrub legumes. The long-term economic viability of hedgerow intercropping depends on the economic setting and the potential for hedgerow intercropping to sustain maize production relative to traditional open-field farming. (C) 1998 Academic Press.

Improving the evidence base for anaesthesia

This paper is a brief report of the symposium, Improving the Evidence Base for Anaesthesia and Intensive Care, organized by the MASTER Anaesthesia Trial Study Group at the Annual Scientific Meeting of the Australian and New Zealand College of Anaesthetists, Newcastle, N.S.W. on Tuesday, May 5, 1998.

Bacteria in shrimp pond sediments: their role in mineralizing nutrients and some suggested sampling strategies

Strategies for sampling sediment bacteria were examined in intensive shrimp, Penaeus monodon (Fabricius), ponds in tropical Australia. Stratified sampling of bacteria at the end of the production season showed that the pond centre, containing flocculated sludge, had significantly higher bacterial counts (15.5 X 10(9) g(-1) dw) than the pond periphery (8.1 X 10(9) g(-1) dw), where the action of aerators had swept the pond floor. The variation in bacterial counts between these two zones within a pond was higher than that between sites within each zone or between ponds. Therefore, sampling effort should be focused within these zones: for example, sampling two ponds at six locations within each of the two zones resulted in a coefficient of variation of approximate to 5%. Bacterial numbers in the sediment were highly correlated with sediment grain size, probably because eroded soil particles and organic waste both accumulated in the centre of the pond. Despite high inputs of organic matter added to the ponds, principally as pelleted feeds, the mean bacterial numbers and nutrient concentrations (i.e. organic carbon, nitrogen and phosphorus) in the sediment were similar to those found in mangrove sediments. This suggests that bacteria are rapidly remineralizing particulates into soluble compounds. Bacterial numbers were highly correlated with organic carbon and total kjeldahl nitrogen in the sediment, suggesting that these were limiting factors to bacterial growth.

Long-term clozapine treatment identifies significant improvements in clinical and functioning scales

The majority of clinical drug trials only cover a small number of variables over a short period of time on a small group of people. The objective of this study was to track a large group of people over a long period of time, using a diverse range of variables with a naturalistic design to assess the ‘real world’ use of clozapine. Fifty-three people with treatment-resistant schizophrenia were recruited into a 2-year study which assessed the subjects using the following scales: Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression Scale (CGI), Life Skills Profile (LSP), and Role Functioning Scale (RFS). Discharge, leave, and ward movement rates were also monitored. All subjects were inpatients at a tertiary psychiatric facility. Thirty-three percent of the group was discharged. Seventythree percent moved to less cost-intensive wards, and the leave rate increased by 105”/0. Sixty-seven percent of the study group were identified as responders by the 24-month time point. Twenty-four percent of the group had their CGI scores reduced to 2 or better 0, =O.OOOl). Significant improvements were identified in the RFS (p = 0.02) and LSP (p = 0.0001). Long-term clozapine treatment has identified a significant group of responders on a variety of measures.

Life tables of the processionary caterpillar Ochrogaster lunifer Herrich-Schaffer (Lepidoptera : Thaumetopoeidae) at local and regional scales

A major ongoing debate in population ecology has surrounded the causative factors underlying the abundance of phytophagous insects and whether or not these factors limit or regulate herbivore populations. However, it is often difficult to identify mortality agents in census data, and their distribution and relative importance across large spatial scales are rarely understood. Were, we present life tables for egg batches and larval cohorts of the processionary caterpillar Ochrogaster lunifer Herrich-Schaffer, using intensive local sampling combined with extensive regional monitoring to ascertain the relative importance of different mortality factors at different localities. Extinction of entire cohorts (representing the entire reproductive output of one female) at natural localities was high, with 82% of the initial 492 cohorts going extinct. Mortality was highest in the egg and early instar stages due to predation from dermestid beetles, and while different mortality factors (e.g. hatching failure, egg parasitism and failure to establish on the host) were present at many localities, dermestid predation, either directly observed or inferred from indirect evidence, was the dominant mortality factor at 89% of localities surveyed. Predation was significantly higher in plantations than in natural habitats. The second most important mortality factor was resource depletion, with 14 cohorts defoliating their hosts. Egg and larval parasitism were not major mortality agents. A combination of predation and resource depletion consistently accounted for the majority of mortality across localities, suggesting that both factors are important in limiting population abundance. This evidence shows that O. lunifer is not regulated by natural enemies alone, but that resource patches (Acacia trees) ultimately, and frequently, act together to limit population growth.

Increased ovulation rate in Merino ewes immunized against small synthetic peptide fragments of the inhibin alpha subunit

Four experiments were carried out in Merino ewes during a period of 4 years to determine the long-term effects of immunization against different synthetic peptides mimicking the amine terminal of the or subunit of porcine inhibin. Peptides were conjugated to human serum albumin and 100-200 mu g emulsified in Freund's complete adjuvant for the primary immunization. Usually two booster injections were given at monthly intervals with 50-100 mu g conjugated peptide using either incomplete Freund's adjuvant or Montanide : Marcel. In some experiments a further immunization was carried in the next year. Blood samples were taken 10 days after each immunization, during the luteal phase, for estimation of gonadotrophin concentrations and determination of inhibin antibody titres. One day after blood sampling cloprostenol was used to induce luteolysis and laparoscopy was performed in the subsequent oestrous cycle. Immunization of ewes with synthetic peptides 1-32, 1-26, 7-26 and 8-30 resulted in large increases in the ovulation rate (OR). An approximately two-fold increase in OR was observed following the first booster immunization with these peptides and a three- to five-fold increase after the second booster immunization. Immunization with these large peptides resulted in a sustained increase in OR for a period of at least 1 year after the second booster immunization. Of the shorter peptides, peptides 10-26 and 13-26 gave a reasonable ovulatory response, although it was more difficult to obtain a response with peptides 1-16, 8-22, 13-25, 8-19 and 10-19; peptides 7-13 and 1-6 gave no response (but were examined for one breeding season only). The smaller peptides led to lower inhibin antibody titres that were not necessarily associated with increased follicle-stimulating hormone (FSH) or OR. More intensive blood sampling in one experiment showed that following primary immunization against peptide 1-32 there was a transient increase in plasma FSH which did not lead to an increased OR. Moreover, a prolonged period of raised FSH after the first booster was significantly correlated with increased OR. In these animals antibody titres were only slightly increased after primary immunization, but after the first booster immunization higher titres were observed that were significantly correlated with trough FSH values and the subsequent OR. These results are interpreted as showing that (1) to obtain an increase in OR peptides 1-32, 1-26 and 7-26 are suitable as immunogens; (2) smaller peptides are less reliable, often require multiple injections, and the response may be delayed; and (3) an extended period of raised plasma FSH is needed to give a large ovulatory response.

X-ray absorption and phase contrast imaging to study the interplay between plant roots and soil structure

Plant performance is, at least partly, linked to the location of roots with respect to soil structure features and the micro-environment surrounding roots. Measurements of root distributions from intact samples, using optical microscopy and field tracings have been partially successful but are imprecise and labour-intensive. Theoretically, X-ray computed micro-tomography represents an ideal solution for non-invasive imaging of plant roots and soil structure. However, before it becomes fast enough and affordable or easily accessible, there is still a need for a diagnostic tool to investigate root/soil interplay. Here, a method for detection of undisturbed plant roots and their immediate physical environment is presented. X-ray absorption and phase contrast imaging are combined to produce projection images of soil sections from which root distributions and soil structure can be analyzed. The clarity of roots on the X-ray film is sufficient to allow manual tracing on an acetate sheet fixed over the film. In its current version, the method suffers limitations mainly related to (i) the degree of subjectivity associated with manual tracing and (ii) the difficulty of separating live and dead roots. The method represents a simple and relatively inexpensive way to detect and quantify roots from intact samples and has scope for further improvements. In this paper, the main steps of the method, sampling, image acquisition and image processing are documented. The potential use of the method in an agronomic perspective is illustrated using surface and sub-surface soil samples from a controlled wheat trial. Quantitative characterization of root attributes, e.g. radius, length density, branching intensity and the complex interplay between roots and soil structure, is presented and discussed.

Weight reduction improves biochemistry and histology in patients with chronic hepatitis C

Hepatitis C virus (HCV) is a major cause of chronic liver disease that may progress to cirrhosis. Antiviral treatment is successful in less than 50% of patients, is costly and causes debilitating side effects. For these reasons, additional therapies to limit the progression of liver disease are urgently required. Steatosis is found in 60% of patients with HCV and is strongly associated with more severe fibrosis. Improvements in biochemical parameters may be seen with weight reduction, however the effects on liver histology have not been investigated. We propose that in patients with chronic HCV and steatosis, obesity contributes to fat in the liver, which results in increased fibrosis and progression to cirrhosis. This study investigated the effect of weight reduction on liver biochemistry and histology in patients with HCV and the success of weight maintenance after an intensive intervention. We examined the effect of a 12 week diet and exercise program where all subjects were seen weekly by the Dietician, with the goal of achieving a 0.5 kg weight loss per week. Biochemistry was monitored monthly and a liver biopsy was performed prior to and 3-6 months after the intervention period. Patients then entered a 12 month weight maintenance program with monthly dietetic review. After 12 weeks there was a mean weight loss of 5.9 ± 3.2 kg and a mean reduction in waist circumference of 9.0 ± 5.0 cm. In 16 of the 19 patients, serum ALT levels fell progressively with weight loss. Mean fasting insulin fell from 16 to 11 mmol/L (p

The polar ionosphere at Zhongshan Station on May 11, 1999, the day the solar wind almost disappeared

The solar wind almost disappeared on May 11,1999: the solar wind plasma density and' dynamic pressure were less than 1 cm(-3) and 0.1 nPa respectively, while the interplanetary magnetic field was northward. The polar ionospheric data observed by the multi-instruments at Zhongshan Station in Antarctica on such special event day was compared with those of the control day (May 14). It was shown that geomagnetic activity was very quiet on May 11 at Zhongshan. The magnetic pulsation, which usually occurred at about magnetic noon, did not appear. The ionosphere was steady and stratified, and the F-2 layer spread very little. The critical frequency of dayside F-2 layer, f(0)F(2), was larger than that of control day, and the peak of f(0)F(2) appeared 2 hours earlier. The ionospheric drift velocity was less than usual. There were intensive auroral E-s appearing at magnetic noon. All this indicates that the polar ionosphere was extremely quiet and geomagnetic field was much more dipolar on May 11. There were some signatures of auroral substorm before midnight, such as the negative deviation of the geomagnetic H component, accompanied with auroral E-s and weak Pc3 pulsation.