2,723 research outputs found
Membrane scaling and prevention techniques during seawater desalination by air gap membrane distillation
Membrane scaling and mitigation techniques during air gap membrane distillation (AGMD) of seawater were investigated. The results showed a strong influence of AGMD operating temperature on not only the process water flux but also membrane scaling and subsequent cleaning efficiency. Elevating feed/coolant temperature from 35/25 to 60/50 °C increased water flux, but also exacerbated membrane scaling of the AGMD process. Membrane scaling was more severe, and occurred at a lower water recovery (68%) when operating at 60/50 °C compared to 35/25 °C (78%) due to increased concentration polarisation effect. Operating temperature also affected the efficiency of the subsequent membrane cleaning. Membrane scaling that occurred at low temperature (i.e. 35/25 °C) was more efficiently cleaned than at high temperature (i.e. 60/50 °C). In addition, membrane cleaning using vinegar was much more efficient than fresh water. Nevertheless, vinegar cleaning could not completely restore the membrane surface to the original condition. Traces of residual scalants on the membrane surface accelerated scaling in the next operation cycle. On the other hand, anti-scalant addition could effectively control scaling. Membrane scaling during AGMD of seawater at 70% water recovery and 60/50 °C was effectively controlled by anti-scalant addition
Phosphonopeptides Revisited, in an Era of Increasing Antimicrobial Resistance
Given the increase in resistance to antibacterial agents, there is an urgent need for the development of new agents with novel modes of action. As an interim solution, it is also prudent to reinvestigate old or abandoned antibacterial compounds to assess their efficacy in the context of widespread resistance to conventional agents. In the 1970s, much work was performed on the development of peptide mimetics, exemplified by the phosphonopeptide, alafosfalin. We investigated the activity of alafosfalin, di-alanyl fosfalin and β-chloro-L-alanyl-β-chloro-L-alanine against 297 bacterial isolates, including carbapenemase-producing Enterobacterales (CPE) (n = 128), methicillin-resistant Staphylococcus aureus (MRSA) (n = 37) and glycopeptide-resistant enterococci (GRE) (n = 43). The interaction of alafosfalin with meropenem was also examined against 20 isolates of CPE. The MIC50 and MIC90 of alafosfalin for CPE were 1 mg/L and 4 mg/L, respectively and alafosfalin acted synergistically when combined with meropenem against 16 of 20 isolates of CPE. Di-alanyl fosfalin showed potent activity against glycopeptide-resistant isolates of Enterococcus faecalis (MIC90; 0.5 mg/L) and Enterococcus faecium (MIC90; 2 mg/L). Alafosfalin was only moderately active against MRSA (MIC90; 8 mg/L), whereas β-chloro-L-alanyl-β-chloro-L-alanine was slightly more active (MIC90; 4 mg/L). This study shows that phosphonopeptides, including alafosfalin, may have a therapeutic role to play in an era of increasing antibacterial resistance
What factors underlie children's susceptibility to semantic and phonological false memories? Investigating the roles of language skills and auditory short-term memory
Two experiments investigated the cognitive skills that underlie children's susceptibility to semantic and phonological false memories in the Deese/Roediger-McDermott procedure (Deese, 1959; Roediger & McDermott, 1995). In Experiment 1, performance on the Verbal Similarities subtest of the British Ability Scales (BAS) II (Elliott, Smith, & McCulloch, 1997) predicted correct and false recall of semantic lures. In Experiment 2, performance on the Yopp-Singer Test of Phonemic Segmentation (Yopp, 1988) did not predict correct recall, but inversely predicted the false recall of phonological lures. Auditory short-term memory was a negative predictor of false recall in Experiment 1, but not in Experiment 2. The findings are discussed in terms of the formation of gist and verbatim traces as proposed by fuzzy trace theory (Reyna & Brainerd, 1998) and the increasing automaticity of associations as proposed by associative activation theory (Howe, Wimmer, Gagnon, & Plumpton, 2009). © 2014 Elsevier B.V
Summary of Major Findings: Learn and Serve America, Higher Education
This report provides an overview of results from the first year evaluation of Learn and Serve America, Higher Education (LSAHE), an initiative of the Corporation for National Service (CNS). The evaluation assessed the impacts of LSAHE on communities, students, and institutions in fiscal year 1995
Carcinogenesis in Prostate Cancer: The role of Long Non-Coding RNAs
LncRNAs appear to play a considerable role in tumourigenesis through regulating key processes in cancer cells such as proliferative signalling, replicative immortality, invasion and metastasis, evasion of growth suppressors, induction of angiogenesis and resistance to apoptosis. LncRNAs have been reported to play a role in prostate cancer, particularly in regulating the androgen receptor signalling pathway. In this review article, we summarise the role of 34 lncRNAs in prostate cancer with a particular focus on their role in the androgen receptor signalling pathway and the epithelial to mesenchymal transition pathway
Incidence and clinical implications of intraoperative BITA grafts conversion. Insights from the Arterial Revascularization Trial
Background: The arterial revascularization trial (ART) has been designed to answer the question whether the use of bilateral internal thoracic arteries (BITA) can improve 10-year outcomes when compared to single internal thoracic artery (SITA). In the ART, a significant proportion of patients initially allocated to BITA received other conduit strategies. We sought to investigate the incidence and clinical implication of BITA grafts conversion in the ART. Methods: Among patients enrolled in the ART (n=3102), we excluded those allocated to SITA (n=1554), those who did not undergo surgery (n=16) and those operated on but withdrew after randomization (n=7). Propensity score matching was used to compare converted vs non-converted BITA groups. Results: A total of 1525 patients were operated with intention to receive BITA grafting. Of those, 233 (15.3%) were converted to other conduit selection strategies. Incidence of conversion largely varied across 28 centres involved (from 0% to 42.9%). The most common reason for BITA grafts conversion was the evidence of at least one internal thoracic artery not suitable which was reported in 77 cases. Patients with intraoperative BITA graft conversion received a lower number of grafts (2.95±0.84 vs 3.21±0.74; P<0.001). However, hospital mortality rate was comparable to those who did not require BITA graft conversion (0 vs 1.6%; P=0.1) as well as the incidence of major complications. At 5 years we found a non-significant excess of deaths (11.9% vs 8.4%; P=0.1) and major adverse events (17.1% 13.2%; P=0.1) mainly driven by an excess of revascularization in patients requiring conversion. Conclusions: The incidence of intraoperative BITA graft conversion is not irrelevant . BITA graft conversion is not associated with increased operative morbidity but its effect on late outcomes remain uncertain
Impact of dual antiplatelet therapy after coronary artery bypass surgery on 1-year outcomes in the Arterial Revascularization Trial
OBJECTIVES: There is still little evidence to boldport routine dual antiplatelet therapy (DAPT) with P2Y12 antagonists following coronary artery bypass grafting (CABG). The Arterial Revascularization Trial (ART) was designed to compare 10-year survival after bilateral versus single internal thoracic artery grafting. We aimed to get insights into the effect of DAPT (with clopidogrel) following CABG on 1-year outcomes by performing a post hoc ART analysis. METHODS: Among patients enrolled in the ART (n  = 3102), 609 (21%) and 2308 (79%) were discharged on DAPT or aspirin alone, respectively. The primary end-point was the incidence of major adverse cerebrovascular and cardiac events (MACCE) at 1 year including cardiac death, myocardial infarction, cerebrovascular accident and reintervention; safety end-point was bleeding requiring hospitalization. Propensity score (PS) matching was used to create comparable groups. RESULTS: Among 609 PS-matched pairs, MACCE occurred in 34 (5.6%) and 34 (5.6%) in the DAPT and aspirin alone groups, respectively, with no significant difference between the 2 groups [hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.59-1.59; P  = 0.90]. Only 188 (31%) subjects completed 1 year of DAPT, and in this subgroup, MACCE rate was 5.8% (HR 1.11, 95% CI 0.53-2.30; P  = 0.78). In the overall sample, bleeding rate was higher in DAPT group (2.3% vs 1.1%; P  = 0.02), although this difference was no longer significant after matching (2.3% vs 1.8%; P  = 0.54). CONCLUSIONS: Based on these findings, when compared with aspirin alone, DAPT with clopidogrel prescribed at discharge was not associated with a significant reduction of adverse cardiac and cerebrovascular events at 1 year following CABG
Post-operative atrial fibrillation and long-term risk of stroke after isolated coronary artery bypass graft surgery
Background: Post-operative atrial fibrillation (pAF) following coronary artery bypass graft-ing (CABG) is a common complication. Whether pAF is associated with an increased risk of cerebrovascular accident (CVA) remains uncertain. We investigated the association between pAF and long-term risk of CVA by performing a post-hoc analysis of 10-year outcomes of the Arterial Revascularization Trial (ART).
Methods: For the present analysis, among patients enrolled in the ART (n=3102), we ex-cluded those who did not undergo surgery (n=25), had a prior history of atrial fibrillation (n=45), or had no information regarding the incidence of pAF (n=9). The final population consisted of 3023 patients of whom 734 (24.3%) developed pAF with the remaining 2289 maintaining sinus rhythm (SR). Competing risk and Cox regression analysis were used to investigate the association between pAF and the risk of CVA.
Results: At 10 years, the cumulative incidence of CVA was 6.3% (4.6-8.1) vs 3.7% (2.9-4.5) in patients with pAF and SR respectively. pAF was an independent predictor of CVA at 10 years (HR 1.53; 95%CI 1.06-2.23; P-value=0.025) even when CVAs that occurred during the index admission were excluded from the analysis (HR 1.47; 95% 1.02-2.11; P=0.04).
Conclusions: Patients with pAF after CABG are at higher risk of CVA. These findings chal-lenge the notion that pAF is a benign complication.</p
Quantum reactive scattering calculations of cross sections and rate constants for the N(2D) + O2(X3Σg-) → O(3Π) + NO(X2Π) reaction
Time-dependent quantum wavepacket calculations have been performed on the two lowest adiabatic potential energy surfaces (2 2A´ and 1 2A˝) for the N(2D) + O2(X3Σg-) → O(3Π) + NO(X2Π) reaction. The calculations have been carried out, on these recently published potential energy surfaces, using the real wavepacket method together with a new dispersion fitted finite difference technique for evaluating the action of the radial kinetic energy operator. Reaction probabilities, corresponding to the O2 reactant in its ground vibrational-rotational state, have been calculated for both surfaces and for many different values of the total angular momentum quantum number (J), within the helicity decoupling approximation. The reaction probabilities associated with all other relevant J values have been interpolated, and to a smaller extent extrapolated, using a capture model, to yield probabilities as a function of energy. The probabilities have in turn been summed to yield energy dependent cross sections and then used to compute rate constants. These rate constants are compared with ones obtained from quasiclassical trajectory (QCT) and variational transition state theory (VTST) calculations performed on the same surfaces. There is a good agreement between the wavepacket and QCT cross sections for reaction on both potential energy surfaces considered, with the exception of the near threshold region, where the reaction probability is dominated by tunnelling. Comparison of the predicted rate constants shows that for the 2 2A´ surface, above 300 K, the wavepacket, QCT and VTST results are quite similar. For the 1 2A˝ surface, however, significant differences occur between the wavepacket and the other methods. These differences become smaller with increasing temperature. It is likely that these differences arise, at least in part, from the fact that, when calculating the rate constants, the reactants are restricted to be in their lowest vibrational-rotational state in the wavepacket calculations but are selected from a thermally equilibrated population in the other methods
Associations between adding a radial artery graft to single and bilateral internal thoracic artery grafts and outcomes. Insights from the Arterial Revascularization Trial
Background—Whether the use of the radial artery (RA) can improve clinical outcomes in coronary artery bypass graft (CABG) surgery remains unclear. The Arterial Revascularization Trial (ART) was designed to compare survival after bilateral internal thoracic artery (BITA) over single left internal thoracic artery (SITA). In the ART, a large proportion of patients (~20%) also received a RA graft instead of a saphenous vein graft (SVG). We aimed to investigate the associations between using the RA instead of SVG to supplement SITA or BITA grafts and outcomes by performing a post-hoc analysis of the ART. Methods—Patients enrolled in the ART (n=3102) were classified based on conduits actually received (as treated). The analysis included 2737 patients who received a RA graft (RA group, n=632) or SVG only (SVG group, n=2105) in addition to SITA or BITA grafts. The primary endpoint was the composite of myocardial infarction, cardiovascular death and repeat revascularization at 5 years. Propensity score matching and stratified Cox regression were used to compare the two strategies. Results—MI, cardiovascular death and repeat revascularization cumulative incidence was 2.3% (95%CI 1.1-3.4), 3.5% (95%CI 2.1-5.0) and 4.4% (95%CI 2.8-6.0) in the RA group and 3.4% (95%CI 2.0-4.8), 4.0% (95%CI 2.5-5.6) and 7.6% (95%CI 5.5- 9.7) in the SVG group respectively. The composite endpoint was significantly lower in the RA group (8.8%; 95%CI 6.5-11.0) when compared with the SVG group (13.6%; 95%CI 10.8-16.3) (P=0.005). This association was present when a RA graft was used to supplement both SITA and BITA grafts (interaction P=0.62). Conclusions—This post-hoc ART analysis showed that an additional RA was associated with lower risk for mid-term major adverse cardiac events when used to supplement SITA or BITA grafts
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