51 research outputs found

    Isolation and Characterization of Organosolv Lignins From Wheat Straw

    Get PDF
    Delignification of wheat straw with aqueous methanol, ethanol, l-propanol, n-butanol, dioxane, and acetone in the presence of acid catalyst (0.02 N H2SO4) at low temperature (75°C) for 2 h was studied. The effect of ethanol-water ratios on the yield of dissolved lignin is also reported here. There was no significant difference in the organosolv lignin yields among the various organic solvents used, which accounted for 24-28% of the total amount of acidic chlorite lignin present in wheat straw. Increase of ethanol-water volume ratio from 40/60 to 70/30 resulted in raising lignin yields from 25 to 31%, while the reverse yield from 31 to 24% appeared in the increase of volume ratio from 70/30 to 90/10. The isolated organosolv lignin fractions contained low amounts of polysaccharide sugars (4.5-5.3%) and had low average molecular weights (1190-1650 Da), which corresponded with the ball-milling lignin, enzyme lignin, and alkali lignin obtained from wheat straw. The predominant components of the alkali nitrobenzene oxidation products were found to be vanillin and syringaldehyde. The yield of vanillin was slightly higher than that of syringaldehyde in all the nitrobenzene oxidation products of the isolated organosolv lignin preparations

    The effect of selected synbiotics on microbial composition and short-chain Fatty Acid production in a model system of the human colon.

    Get PDF
    Prebiotics, probiotics and synbiotics can be used to modulate both the composition and activity of the gut microbiota and thereby potentially affecting host health beneficially. The aim of this study was to investigate the effects of eight synbiotic combinations on the composition and activity of human fecal microbiota using a four-stage semicontinuous model system of the human colon.Carbohydrates were selected by their ability to enhance growth of the probiotic bacteria Lactobacillus acidophilus NCFM (NCFM) and Bifidobacterium animalis subsp. lactis Bl-04 (Bl-04) under laboratory conditions. The most effective carbohydrates for each probiotic were further investigated, using the colonic model, for the ability to support growth of the probiotic bacteria, influence the composition of the microbiota and stimulate formation of short-chain fatty acids (SCFA).The following combinations were studied: NCFM with isomaltulose, cellobiose, raffinose and an oat β-glucan hydrolysate (OBGH) and Bl-04 with melibiose, xylobiose, raffinose and maltotriose. All carbohydrates showed capable of increasing levels of NCFM and Bl-04 during fermentations in the colonic model by 10(3)-10(4) fold and 10-10(2) fold, respectively. Also the synbiotic combinations decreased the modified ratio of Bacteroidetes/Firmicutes (calculated using qPCR results for Bacteroides-Prevotella-Porphyromonas group, Clostridium perfringens cluster I, Clostridium coccoides - Eubacterium rectale group and Clostridial cluster XIV) as well as significantly increasing SCFA levels, especially acetic and butyric acid, by three to eight fold, as compared to the controls. The decreases in the modified ratio of Bacteroidetes/Firmicutes were found to be correlated to increases in acetic and butyric acid (p=0.04 and p=0.03, respectively).The results of this study show that all synbiotic combinations investigated are able to shift the predominant bacteria and the production of SCFA of fecal microbiota in a model system of the human colon, thereby potentially being able to manipulate the microbiota in a way connected to human health

    Perceived Object Stability Depends on Multisensory Estimates of Gravity

    Get PDF
    BACKGROUND: How does the brain estimate object stability? Objects fall over when the gravity-projected centre-of-mass lies outside the point or area of support. To estimate an object's stability visually, the brain must integrate information across the shape and compare its orientation to gravity. When observers lie on their sides, gravity is perceived as tilted toward body orientation, consistent with a representation of gravity derived from multisensory information. We exploited this to test whether vestibular and kinesthetic information affect this visual task or whether the brain estimates object stability solely from visual information. METHODOLOGY/PRINCIPAL FINDINGS: In three body orientations, participants viewed images of objects close to a table edge. We measured the critical angle at which each object appeared equally likely to fall over or right itself. Perceived gravity was measured using the subjective visual vertical. The results show that the perceived critical angle was significantly biased in the same direction as the subjective visual vertical (i.e., towards the multisensory estimate of gravity). CONCLUSIONS/SIGNIFICANCE: Our results rule out a general explanation that the brain depends solely on visual heuristics and assumptions about object stability. Instead, they suggest that multisensory estimates of gravity govern the perceived stability of objects, resulting in objects appearing more stable than they are when the head is tilted in the same direction in which they fall

    The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

    Get PDF
    Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

    PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

    Get PDF
    Abstract Background Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment. Methods All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals. Results A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death. Conclusion Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions. </jats:sec

    Natural disaster: unnatural response: an intervention and recovery framework informed by the case of T.Vilufushi, Maldives, following the 2004 Asian Tsunami

    No full text
    © 2012 Dr. Peter Mark LawtherLonger term community recovery from natural disasters remains one of the least researched and least understood aspects of such events. The significance of this knowledge gap is underscored by the expected increase in the frequency of natural disasters events due to global climate change, and their impact upon a burgeoning world population. As a result, more people are expected to be directly affected by future natural disasters. In addition, global media exposure of natural disasters ensures that they are part of the lived experience of many more people beyond those directly affected. Such exposure is symptomatic of the contemporary response to natural disaster events which is also characterised by Government opportunism coupled with Agency legitimisation and servitude to Donors. This contemporary response to natural disaster events juxtaposes between that of Governments and Agencies (the exogenous), and the affected community (the endogenous). The extent to which these two response mechanisms are able to articulate is crucial to long term recovery propensity of affected communities from natural disaster events. This research investigates such articulation by constructing a bespoke analytical framework to investigate the relationship between the scale of post-disaster response interventions, the extent of community participation in them, and their impact upon community recovery from natural disaster. The framework is posited within a naturalistic inductive research paradigm and applied to study the community recovery of Vilufushi Island, Republic of Maldives, following the 2004 Asian Tsunami. Vilufushi was all but completely destroyed by the Tsunami. The population of 1800 were relocated for a period of 4.5 years whilst the Government of Maldives redeveloped Vilufushi as a “Focus” Island, with international assistance, to further their pre-existing national population consolidation policy. As a result, Vilufushi was quadrupled in size, a new land use plan was imposed and almost all infrastructure was rebuilt. The Vilufushi community returned to their “new” home in May 2009. Field data collection comprised focus groups discussions, key informant interviews and observations. This was supplemented with ongoing document collection and review. Data was analysed using an individual reductionist pattern match technique, preceding a holistic network analysis. The results of the analysis identified broad relationships between the three variables of the analytical framework; scale of intervention, extent of community participation, and impact upon recovery. Higher (renewal) and lower (replacement) interventions were characterized by a comparatively lower extent of community participation, and negative / variable impact upon recovery. Enhancement scale response interventions were characterized by a greater extent of participation, and a positive impact upon recovery. Informed by the results of the case study, and also existing knowledge frames of resilience theory and adaptive co-management, a testable post-disaster intervention and recovery framework is developed. The framework can be applied to provide inter-disciplinary guidance to the design, implementation, monitoring and evaluation of future post-disaster interventions to enhance recovery outcomes of communities affected by natural disaster events
    corecore