3,414 research outputs found
An integrated process for biomass pyrolysis oil upgrading: A synergistic approach
Biomass pyrolysis is a promising path toward renewable liquid fuels. However, the calorific value of the pyrolysis oil (PO), also known as bio-oil, is low due to the high content of organic oxygenates and water. The oxygen content of PO can be reduced by hydrodeoxygenation, in which hydrogen is used to remove oxygen. An economic disadvantage of hydrodeoxygenation pathway is its dependence on hydrogen as an expensive feedstock. An alternative technology is to upgrade PO in hot, high pressure water, known as hydrothermal processing. The present paper studies upgrading pyrolysis oil derived from Norwegian spruce by (1) hydrodeoxygenation in a liquid hydrocarbon solvent using nanodispersed sulphide catalysts and (2) hydrothermal treatment in near-supercritical water. Experimental results and simulation studies suggested that if water soluble products are reformed for hydrogen production, the hydrodeoxygenation pathway would be a net consumer of hydrogen, whilst the hydrothermal pathway could produce a significant hydrogen excess. By comparison, the fuel yield from hydrodeoxygenation was significantly higher than hydrothermally treated fuel. Therefore, in the present study, an integrated model was proposed which demonstrates that the synergistic integration of hydrothermal and hydrodeoxygenation upgrading technologies can yield an optimal configuration which maximises fuel production, whilst obviating the need to purchase hydrogen. In this optimal configuration, 32% of raw pyrolysis-oil is hydrothermally treated and the rest is sent for hydrodeoxygenation. The results of a techno-economic analysis suggests that if the proposed integrated approach is used, it is possible to produce biofuel (43% gasoline, and 57% diesel) at a very competitive minimum selling price of 428 /gallon)
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Positive effects of methylphenidate on hyperactivity are moderated by monoaminergic gene variants in children with autism spectrum disorders.
Methylphenidate (MPH) reduces hyperactive-impulsive symptoms common in children with autism spectrum disorders (ASDs), however, response and tolerability varies widely. We hypothesized monoaminergic gene variants may moderate MPH effects in ASD, as in typically developing children with attention-deficit/hyperactivity disorder. Genotype data were available for 64 children with ASD and hyperactivity who were exposed to MPH during a 1-week safety/tolerability lead-in phase and 58 who went on to be randomized to placebo and three doses of MPH during a 4-week blinded, crossover study. Outcome measures included the Clinical Global Impression-Improvement (CGI-I) scale and the Aberrant Behavior Checklist (ABC-hyperactivity index). A total of 14 subjects discontinued the study because of MPH side effects. Subjects were genotyped for variants in DRD1-DRD5, ADRA2A, SLC6A3, SLC6A4, MAOA and MAOB, and COMT. Forty-nine percent of the sample met positive responder criteria. In this modest but relatively homogeneous sample, significant differences by DRD1 (P=0.006), ADRA2A (P<0.02), COMT (P<0.04), DRD3 (P<0.05), DRD4 (P<0.05), SLC6A3 (P<0.05) and SLC6A4 (P<0.05) genotypes were found for responders versus non-responders. Variants in DRD2 (P<0.001) and DRD3 (P<0.04) were associated with tolerability in the 14 subjects who discontinued the trial. For this first MPH pharmacogenetic study in children with ASD, multiple monoaminergic gene variants may help explain individual differences in MPH's efficacy and tolerability
Patients with severe acuteâonâchronic liver failure are disadvantaged by model for endâstage liver diseaseâbased organ allocation policy
Background: Mortality for patients with acuteâonâchronic liver failure (ACLF) may be underestimated by the model for endâstage liver diseaseâsodium (MELDâNa) score. /
Aim: To assess waitlist outcomes across varying grades of ACLF among a cohort of patients listed with a MELDâNa score â„35, and therefore having similar priority for liver transplantation. /
Methods: We analysed the United Network for Organ Sharing (UNOS) database, years 2010â2017. Waitlist outcomes were evaluated using Fine and Gray's competing risks regression. /
Results: We identified 6342 candidates at listing with a MELDâNa score â„35, of whom 3122 had ACLFâ3. Extraâhepatic organ failures were present primarily in patients with four to six organ failures. Competing risks regression revealed that candidates listed with ACLFâ3 had a significantly higher risk for 90âday waitlist mortality (Subâhazard ratio (SHR) = 1.41; 95% confidence interval [CI] 1.12â1.78) relative to patients with lower ACLF grades. Subgroup analysis of ACLFâ3 revealed that both the presence of three organ failures (SHR = 1.40, 95% CI 1.20â1.63) or four to six organ failures at listing (SHR = 3.01; 95% CI 2.54â3.58) was associated with increased waitlist death. Candidates with four to six organ failures also had the lowest likelihood of receiving liver transplantation (SHR = 0.61, 95% CI 0.54â0.68). The Share 35 rule was associated with reduced 90âday waitlist mortality among the full cohort of patients listed with ACLFâ3 and MELDâNa score â„35 (SHR = 0.59; 95% CI 0.49â0.70). However, Share 35 rule implementation was not associated with reduced waitlist mortality among patients with four to six organ failures (SHR = 0.76; 95% CI 0.58â1.02). /
Conclusion: The MELDâNa score disadvantages patients with ACLFâ3, both with and without extraâhepatic organ failures. Incorporation of organ failures into allocation policy warrants further exploration
Microstructured reactor as a pre-turbo catalytic converter
The idea of a structured catalytic converter
placed immediately after engine exhaust valves, thus
operating on high gas temperature and velocity, is
explored. The assumption is that major part of the reactor
operates in the entry region where Nusselt and Sherwood
numbers are highly enhanced. In this work, flow resistances
as well as heat and mass transfer coefficients were studied
for gas velocities exceeding 50 m/s. Consequently, the
transition range (between laminar and turbulent flows) was
reached. The comparison with classic monolith has shown
significant improvement in heat or mass transfer paid by
slight increase in flow resistance
An observational prospective study of topical acidified nitrite for killing methicillin-resistant Staphylococcus aureus (MRSA) in contaminated wounds
Background Endogenous nitric oxide (NO) kills bacteria and other organisms as part of the innate immune response. When nitrite is exposed to low pH, NO is generated and has been used as an NO delivery system to treat skin infections. We demonstrated eradication of MRSA carriage from wounds using a topical formulation of citric acid (4.5%) and sodium nitrite (3%) creams co-applied for 5 days to 15 wounds in an observational prospective pilot study of 8 patients. Findings Following treatment with topical citric acid and sodium nitrite, 9 of 15 wounds (60%) and 3 of 8 patients (37%) were cleared of infection. MRSA isolates from these patients were all sensitive to acidified nitrite in vitro compared to methicillin-sensitive S. aureus and a reference strain of MRSA. Conclusions Nitric oxide and acidified nitrite offer a novel therapy for control of MRSA in wounds. Wounds that were not cleared of infection may have been re-contaminated or the bioavailability of acidified nitrite impaired by local factors in the tissue
The novel mTOR inhibitor RAD001 (Everolimus) induces antiproliferative effects in human pancreatic neuroendocrine tumor cells
Background/Aim: Tumors exhibiting constitutively activated PI(3) K/Akt/mTOR signaling are hypersensitive to mTOR inhibitors such as RAD001 (everolimus) which is presently being investigated in clinical phase II trials in various tumor entities, including neuroendocrine tumors (NETs). However, no preclinical data about the effects of RAD001 on NET cells have been published. In this study, we aimed to evaluate the effects of RAD001 on BON cells, a human pancreatic NET cell line that exhibits constitutively activated PI(3) K/Akt/mTOR signaling. Methods: BON cells were treated with different concentrations of RAD001 to analyze its effect on cell growth using proliferation assays. Apoptosis was examined by Western blot analysis of caspase-3/PARP cleavage and by FACS analysis of DNA fragmentation. Results: RAD001 potently inhibited BON cell growth in a dose-dependent manner which was dependent on the serum concentration in the medium. RAD001-induced growth inhibition involved G0/G1-phase arrest as well as induction of apoptosis. Conclusion: In summary, our data demonstrate antiproliferative and apoptotic effects of RAD001 in NET cells in vitro supporting its clinical use in current phase II trials in NET patients. Copyright (c) 2007 S. Karger AG, Basel
A tool for functional brain imaging with lifespan compliance
The human brain undergoes significant functional and structural changes in the first decades of life, as the foundations for human cognition are laid down. However, non-invasive imaging techniques to investigate brain function throughout neurodevelopment are limited due to growth in head-size with age and substantial head movement in young participants. Experimental designs to probe brain function are also limited by the unnatural environment typical brain imaging systems impose. However, developments in quantum technology allowed fabrication of a new generation of wearable magnetoencephalography (MEG) technology with the potential to revolutionise electrophysiological measures of brain activity. Here we demonstrate a lifespan-compliant MEG system, showing recordings of high fidelity data in toddlers, young children, teenagers and adults. We show how this system can support new types of experimental paradigm involving naturalistic learning. This work reveals a new approach to functional imaging, providing a robust platform for investigation of neurodevelopment in health and disease
Acute toxicity, brine shrimp cytotoxicity and relaxant activity of fruits of callistemon citrinus curtis
<p>Abstract</p> <p>Background</p> <p><it>Callistemon citrinus </it>Curtis belongs to family Myrtaceae that has a great medicinal importance. In our previous work, fruits of <it>Callistemon citrinus </it>were reported to have relaxant (antispasmodic) activity. The current work describes the screening of fractions of the crude methanol extract for tracing spasmolytic constituents so that it shall help us for isolation of bioactive compounds. Acute toxicity and brine shrimp cytotoxicity of crude methanol extract are also performed to standardize it.</p> <p>Methods</p> <p>The crude methanol extract was obtained by maceration with distilled water (500 ml) three times and fractionated successively with <it>n-</it>hexane, chloroform, ethyl acetate and <it>n-</it>butanol (300 ml of each solvent). Phytochemical analysis for crude methanol extract was performed. Acute toxicity studies were performed in mice. Brine shrimp cytotoxicity studies were performed to determine its cytotoxicity and standardize it. In other series of experiments, rabbits' jejunum preparations were used in screening for possible relaxant activities of various fractions. They were applied in concentrations of 0.01, 0.03, 0.1, 0.3, 1.0, 3.0, 5.0 and 10.0 mg/ml on spontaneous rabbits' jejunum preparations. In similar fashion, fractions were also tested on KCl (80 mM) -induced contractions. Calcium chloride curves were constructed in K-rich Tyrode's solution. The effects of various fractions were tested on calcium chloride curves at concentrations 1.0, 3.0, 5.0 and 10.0 mg/ml. Curves of verapamil used as reference drug at concentration 0.1 ΌM and 0.3 ΌM were also constructed. The curves were compared with their respective controls for possible right shift.</p> <p>Results</p> <p>Methanol extract tested strongly positive for saponins and tannins. However, it tested mild positive for presence of proteins, amino acids, carbohydrates and phenolic compounds. LD<sub>50 </sub>value for crude methanol extract is 476.25 ± 10.3 (470-481, n = 4) mg/ml. Similarly, EC<sub>50 </sub>value for brine shrimp cytotoxicity is 65.5 ± 7.28 (60.8- 69.4, n = 4) mg/ml. All the fractions relaxed the spontaneous and KCl-induced contractions. EC<sub>50 </sub>values (mg/ml) for effects of ethyl acetate fraction on spontaneous and KCl induced contractions are 2.62 ± 0.78 (2.15-3.0, n = 4) and 3.72 ± 0.86 (3.38-4.28, n = 4) respectively. Respective EC<sub>50 </sub>values (mg/ml) for <it>n-</it>butanol fraction are 3.59 ± 0.2(3.07-3.9, n = 4) for spontaneous, and 5.57 ± 0.2 (5.07-6.11, n = 4) for KCl- induced contractions. EC<sub>50 </sub>value for control calcium chloride curve (without extract) is -2.73 ± 0.19 (-2.6 - -2.81, n = 4) while EC<sub>50 </sub>for curves treated with 5.0 mg/ml of chloroform is -2.22 ± 0.02 (-2.16 - -2.3, n = 4). EC<sub>50 </sub>value for ethyl acetate treated (1.0 mg/ml) tissues is -1.95 ± 0.10 (-1.88 - -2.0, n = 4) <it>vs</it>. control EC<sub>50 </sub>= -2.71 ± 0.08 (-2.66 - -2.76, n = 4). All the fractions, except <it>n-</it>hexane, showed a right shift like that of verapamil (EC<sub>50 </sub>= -1.72 ± 0.15 (-1.62 - -1.8, n = 4) vs. Control EC<sub>50 </sub>= -2.41 ± 0.06 (-2.38 - - 2.44, n = 4), a standard drug that blocks voltage operated calcium channels.</p> <p>Conclusion</p> <p>Relaxant constituents were more concentrated in ethylacetate fraction followed by chloroform, <it>n -</it>butanol and aqueous fractions that warrant for its isolation. The crude methanol extract is safe at concentration 250 mg/ml or below and results of brine shrimp cytotoxicity assay imply the plant specie may be a source of cytotoxic agents.</p
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