28,163 research outputs found
An investigation of the grindability of two torrefied energy crops
The process of torrefaction alters the physical properties of biomass, reducing its fibrous tenacious nature. This could allow increased rates of co-milling and therefore co-firing in coal fired power stations, which in turn would enable a reduction in the amount of coal used and an increase in the use of sustainable fuels, without the need for additional plant. This paper presents an experimental investigation of the pulverisation behaviour of two torrefied energy crops, namely: willow and Miscanthus. A multifactorial method approach was adopted to investigate the three process parameters of temperature, residence time and particle size, producing fuels treated using four different torrefaction conditions. The untreated and torrefied fuels were subjected to standard fuel analysis techniques including ultimate analysis, proximate analysis and calorific value determination. The grindability of these fuels was then determined using a laboratory ball mill and by adapting the Hardgrove Grindability Index (HGI) test for hard coals. After grinding, two sets of results were obtained. Firstly a determination similar to the HGI test was made, measuring the proportion of sample passing through a 75 mu m sieve and plotting this on a calibrated HGI chart determined using four standard reference coals of known HGI values. Secondly the particle size distributions of the entire ground sample were measured and compared with the four standard reference coals. The standard fuel tests revealed that temperature was the most significant parameter in terms of mass loss, changes in elemental composition and energy content increase. The first grindability test results found that the untreated fuels and fuels treated at low temperatures showed very poor grindability behaviour. However, more severe torrefaction conditions caused the fuels to exhibit similar pulverisation properties as coals with low HGI values. Miscanthus was found to have a higher HGI value than willow. On examining the particle size distributions it was found that the particle size distributions of torrefied Miscanthus differed significantly from the untreated biomass and had comparable profiles to those of the standard reference coals with which they had similar HGI values. However, only the torrefied willow produced at the most severe conditions investigated exhibited this behaviour, and the HGI of torrefied willow was not generally a reliable indicator of grindability performance for this energy crop. Overall it was concluded that torrefied biomass can be successfully pulverised and that torrefied Miscanthus was easier to grind than torrefied willow
Manipulating the Hâ‚‚/CO ratio from dry reforming of simulated mixed waste plastics by the addition of steam
Two-stage pyrolysis-catalytic reforming of plastics was investigated with the aim of producing usable quality synthesis gases (syngas) comprised of H2 and CO. The process consisted of pyrolysis of the plastics in the first stage and catalytic reforming with CO2 and steam as the reforming agents in the second stage. The plastics used were a mixture of waste plastics prepared to represent those found in municipal solid waste and the catalysts studied were Ni-Co/Al2O3 and Ni-Mg/Al2O3 prepared by the rising pH technique. A range of different CO2/steam ratios were considered; 4:0, 4:0.5, 4:1, 4:1.5 and 4:2 for the Ni-Co/Al2O3 catalyst and 4:0, 4:0.5, 4:1, 4:2 and 4:3 for the Ni-Mg/Al2O3 catalyst. The results obtained demonstrated that the catalysts and the CO2/steam ratio influence the syngas quality, as represented by the H2/CO molar ratio value. With the Ni-Co/Al2O3 catalyst, the H2/CO molar ratio was increased from 0.74 (no steam) to 0.94 (CO2:steam ratio; 4:1) however the H2/CO molar ratio decreased with further steam addition. Results using the Ni-Mg/Al2O3 catalyst showed a different trend, wherein the H2/CO molar ratio increased with the increase of steam addition into the system. From the evaluation of the gas composition, the steam addition with the Ni-Mg/Al2O3 catalyst promoted hydrogen production while the Ni-Co/Al2O3 catalyst promoted carbon monoxide production. The addition of steam to the dry reforming of waste plastics has the potential to manipulate the H2/CO molar ratio hence, the quality of syngas produced can be matched to the desired end-use industrial application
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Iron-binding fragments from the N-Terminal and C-Terminal regions of human lactoferrin
Digestion of lactoferrin with pepsin at pH 3.0 gave an iron-binding half-molecule that
represents the C-terminal part of the native protein. Tryptic or chymotryptic digestion
of 30%/-iron-saturated lactoferrin yielded the N- and C-terminal half molecules, which
could be separated by DEAE-Sephadex chromatography. The N- and C-terminal fragments
did not show any immunological cross-reaction. The carbohydrate of lactoferrin
was distributed equally between the two fragments
Pressure-induced delocalization of photoexcited states in a semiconducting polymer.
We present broadband transient absorption spectroscopy on the fluorescent copolymer poly(9,9-dioctylfluorene-co-benzothiadiazole) under hydrostatic pressure of up to 75Â kbar. We observe a strong reduction of the stimulated emission intensity under pressure, coupled with slower decay kinetics and reduced fluorescence intensity. These observations indicate increased delocalization of photogenerated singlet excitons, facilitated by an increased dielectric constant at high pressure. Spin triplet excitons, generated via an iridium complex-F8BT oligomer, show reduced lifetimes under pressure
Significant familial differences in the frequency of abortion and Toxoplasma gondii infection within a flock of Charollais sheep
A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27
families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since
1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of
congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. Atotal of
155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant
differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging
between 0% and 48% (P<0.01). Significantly different infection frequencies with T. gondii were also observed for different
families and ranged between 0% and 100% (P<0.01). Although the actual cause of each abortion was not verified, a highly
significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection
in the same families (P<0.01). The data presented here raise further questions regarding the significance of congenital
transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families
of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work
invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods
in the future.
Key words: Toxoplasma gondii, ovine, toxoplasmosis, congenital, transmission, pedigree, sheep
High levels of congenital transmission of toxoplasma gondii in longitudinal and cross-sectional studies on sheep farms provides evidence of vertical transmission in ovine hosts
Recent research suggests that vertical transmission may play an important role in sustaining Toxoplasma gondii infection in some species. We report here that congenital transmission occurs at consistently high levels in pedigree Charollais and outbred sheep flocks sampled over a 3-year period. Overall rates of transmission per pregnancy determined by PCR based diagnosis, were consistent over time in a commercial sheep flock (69%) and in sympatric (60%) and allopatric (41%) populations of Charollais sheep. The result of this was that 53·7% of lambs were acquiring an infection prior to birth: 46·4% of live lambs and 90·0% of dead lambs (in agreement with the association made between T. gondii and abortion). No significant differences were observed between lamb sexes. Although we cannot distinguish between congenital transmission occurring due to primary infection at pregnancy or reactivation of chronic infection during pregnancy, our observations of consistently high levels of congenital transmission over successive lambings favour the latter
Detection of high levels of congenital transmission of toxoplasma gondii in natural urban populations of mus domesticus
The relative importance of different transmission routes of Toxoplasma gondii has been a matter for debate. This ubiquitous parasite is generally thought to be transmitted by infective oocysts excreted by the definitive host, the cat. Ingestion of undercooked meat has also been considered an important route of transmission in many mammals while congenital transmission has generally been considered relatively rare. Experimental studies demonstrate the ability of T. gondii to be transmitted congenitally, but few studies have investigated the frequency of this transmission route in natural populations. We use PCR amplification of the SAG1 gene to investigate the frequency of congenital transmission in a wild population of mice (Mus domesticus) and show that congenital transmission is occurring in 75% of pregnancies in this population. Furthermore, for infected pregnant mice, transmission occurs to at least one foetus in 100% of cases while variable penetrance of congenital infection is observed. These high levels of congenital transmission in this wild population of mice, taken together with other recent data on congenital transmission in sheep, suggests that this phenomenon might be more widespread than previously thought
Can food vouchers improve nutrition and reduce health inequalities in low-income mothers and young children: A multi-method evaluation of the experiences of beneficiaries and practitioners of the Healthy Start programme in England
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Good nutrition is important during pregnancy, breastfeeding and early life to optimise the health of women and children. It is difficult for low-income families to prioritise spending on healthy food. Healthy Start is a targeted United Kingdom (UK) food subsidy programme that gives vouchers for fruit, vegetables, milk, and vitamins to low-income families. This paper reports an evaluation of Healthy Start from the perspectives of women and health practitioners. Methods. The multi-method study conducted in England in 2011/2012 included focus group discussions with 49 health practitioners, an online consultation with 620 health and social care practitioners, service managers, commissioners, and user and advocacy groups, and qualitative participatory workshops with 85 low-income women. Additional focus group discussions and telephone interviews included the views of 25 women who did not speak English and three women from Traveller communities. Results: Women reported that Healthy Start vouchers increased the quantity and range of fruit and vegetables they used and improved the quality of family diets, and established good habits for the future. Barriers to registration included complex eligibility criteria, inappropriate targeting of information about the programme by health practitioners and a general low level of awareness among families. Access to the programme was particularly challenging for women who did not speak English, had low literacy levels, were in low paid work or had fluctuating incomes. The potential impact was undermined by the rising price of food relative to voucher value. Access to registered retailers was problematic in rural areas, and there was low registration among smaller shops and market stalls, especially those serving culturally diverse communities. Conclusions: Our evaluation of the Healthy Start programme in England suggests that a food subsidy programme can provide an important nutritional safety net and potentially improve nutrition for pregnant women and young children living on low incomes. Factors that could compromise this impact include erosion of voucher value relative to the rising cost of food, lack of access to registered retailers and barriers to registering for the programme. Addressing these issues could inform the design and implementation of food subsidy programmes in high income countries. © 2014 McFadden et al.; licensee BioMed Central Ltd.The Policy Research Programme in the Department of Health, UK
The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations
Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4·4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18·9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues
Impact of pain and postoperative complications on patient-reported outcome measures 5Â years after microvascular decompression or partial sensory rhizotomy for trigeminal neuralgia
BACKGROUND: Microvascular decompression (MVD) and partial sensory rhizotomy (PSR) provide longstanding pain relief in trigeminal neuralgia (TN). Given their invasiveness, complications can result from such posterior fossa procedures, but the impact of these procedures and their complications on patient-reported outcome measures (PROM), such as quality of life and distress, are not well established. METHOD: Five years after surgery, patients who underwent first MVD or PSR for TN at one institution, between 1982 and 2002, were sent a self-completion assessment set containing a range of PROMs: the Short Form-12 (SF-12) questionnaire to assess quality of life, the Hospital Anxiety and Depression Scale (HADS) to assess distress, and a questionnaire containing questions about postoperative complications, their severity and impact on quality of life. These findings and demographic data were compared between MVD and PSR. RESULTS: One hundred and eighty-one of 245 (73.9%) patients after first MVD and 49 of 60 (81.7%) after PSR responded, and were included in analyses. The mean SF-12 scores of patients after MVD and PSR at five-year follow-up were significantly lower than English age-matched norms. Though there were no differences in SF-12 physical or mental component scores between the two procedures, patients after PSR were more likely to have case-level anxiety (RR = 3.3; 95% CI, 1.1-10.5; p = 0.03), had more postoperative complications, and of greater severity, including pain (RR = 2.52; 95% CI, 1.5-4.1; p < 0.001), numbness (RR = 5.9; 95% CI, 3.8-9.2; p < 0.001), burning sensations (RR = 3.0; 95% CI, 1.5-5.8; p = 0.001) and difficulty in eating (RR = 17.1; 95% CI, 5.6-53.1; p < 0.001), and these had a larger impact on quality of life for PSR compared to MVD. CONCLUSIONS: The quality of life 5 years after MVD or PSR is poorer than in the general population and associated with postoperative complications such as pain, numbness, burning sensation and difficulty in eating. These complications are commoner after PSR than MVD, and this is associated with anxiety in PSR patients at five-year follow-up. However, these differences are not reflected by quality of life scores. Outcome measures need to incorporate patient experience after treatment for TN, and represent patient priorities for quality of life
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