1,466 research outputs found
Sulfonic-Functionalized Carbon Catalyst for Esterification of High Free Fatty Acid
AbstractWe report synthesis and characteristics of sulfonic-functionalized carbon catalyst in this work. The carbon soild acid was prepared through the sulfonation of the incomplete carbonized mung bean vermicelli and was used as a solid acid catalyst for esterification of high free fatty acid. The catalyst (SBET = 18.1 m2/g, acid site density of 1.53 mmol H+/gcat) could exhibit high esterification activity in the reaction of oleic acid with methanol due to the efficient accessibility of bulky substrate molecule to sulfonic active site during the reaction. This environmentally benign and ecofriendly C-SO3H catalyst could be suited to esterify high FFA feedstocks reducing the production cost of biodiesel
Airphoto Lineaments in the Caledonia Area of Southern New Brunswick
A system of photogeologic interpretation has been applied on a regional scale in the Caledonia area of New Brunswick, Canada, The orientation of about 700 photolineaments has been measured and their distribution analysed. A statistical partitioning technique applied to the whole region produced six major trends with the strongest trends occurring at 097o±7o, 165o±6o and 141o±9o . None of the strong trends coincides with the orientation of major faults in the area. Detailed examination of structural domains suggests the presence of more than six lineament trends. Correlation of trends from domain to domain is difficult and the genetic significance of lineaments in view of the scarcity of ground information remains in doubt
Operational experiences associated with the implementation of near point-of-care early infant diagnosis of HIV in Myanmar: a qualitative study
Background: Timely diagnosis and early initiation of life-saving antiretroviral therapy are critical factors in preventing mortality among HIV-infected infants. However, resource-limited settings experience numerous challenges associated with centralised laboratory-based testing, including low rates of testing, complex sample referral pathways and unacceptably long turnaround times for results. Point-of-care (POC) HIV testing for HIVexposed infants can enable same-day communication of results and early treatment initiation for HIV-infected infants. However, complex operational issues and service integration can limit utility and must be well understood prior to implementation. We explored and documented the challenges and enabling factors in implementing the POC Xpert® HIV-1 Qual test (Cepheid, Sunnyvale, CA, USA) for early infant diagnosis (EID) as part of routine services in four public hospitals in Myanmar.
Methods: This sub-study was part of a randomised controlled stepped-wedge trial (Australian and New Zealand Clinical Trials Registry, number 12616000734460) designed to investigate the impact of POC testing for EID in Myanmar and Papua New Guinea. Infants recruited during the intervention phase underwent POC testing at the participating hospitals as part of routine care. Semi-structured interviews with 23 caregivers, 12 healthcare providers and 10 key informants were used to explore experiences of POC-EID testing. The research team and hospital staff documented and discussed implementation challenges throughout the study.
Results: Overall, caregivers and healthcare workers were satisfied with the short turnaround time of the POC test. Occasional delays in POC testing were mostly attributable to late receipt of samples by laboratory technicians and communication constraints among healthcare staff. Hospital staff valued technical assistance from the research group and the National Health Laboratory. Despite staff shortages and infrastructure challenges such as unreliable electricity supply and cramped space, healthcare workers and caregivers found the implementation of the POC test to be feasible at pilot sites.
Conclusions: As plans for national scale-up evolve, there needs to be a continual focus on staff training, communication pathways and infrastructure. Other models of care, such as allowing non-laboratory-trained personnel to perform POC testing, and cost effectiveness should also be evaluated
Understanding Lung Carcinogenesis from a Morphostatic Perspective:Prevention and Therapeutic Potential of Phytochemicals for Targeting Cancer Stem Cells
Lung cancer is still one of the deadliest cancers, with over two million incidences annually. Prevention is regarded as the most efficient way to reduce both the incidence and death figures. Nevertheless, treatment should still be improved, particularly in addressing therapeutic resistance due to cancer stem cells—the assumed drivers of tumor initiation and progression. Phytochemicals in plant-based diets are thought to contribute substantially to lung cancer prevention and may be efficacious for targeting lung cancer stem cells. In this review, we collect recent literature on lung homeostasis, carcinogenesis, and phytochemicals studied in lung cancers. We provide a comprehensive overview of how normal lung tissue operates and relate it with lung carcinogenesis to redefine better targets for lung cancer stem cells. Nine well-studied phytochemical compounds, namely curcumin, resveratrol, quercetin, epigallocatechin-3-gallate, luteolin, sulforaphane, berberine, genistein, and capsaicin, are discussed in terms of their chemopreventive and anticancer mechanisms in lung cancer and potential use in the clinic. How the use of phytochemicals can be improved by structural manipulations, targeted delivery, concentration adjustments, and combinatorial treatments is also highlighted. We propose that lung carcinomas should be treated differently based on their respective cellular origins. Targeting quiescence-inducing, inflammation-dampening, or reactive oxygen species-balancing pathways appears particularly interesting
Numerical Flow Analysis of an Axial Flow Pump
This paper describes the detailed study of fluid flows in an axial pump that includes impeller and guide vanes. And the comparisons of flow simulations of the axial pump impeller with guide vanes and without guide vanes are carried out in this paper. In addition to this, the effect of number of guide blades on flow behaviours is analysed numerically. The computational results are performed by using one of CFD commercial software, Solidworks Flow Simulation. The input design data of the model pump are the flow rate of 0.2m3, head of 3m and the rotational speed of 1160 rpm. The outer and inner diameter of impeller is 0.3m and 0.15m respectively. . And the impeller with four blades is used in this paper. The guide blade number is varied to 5,7,9nbsp with the same input data and other geometric parameters keep constant. In this study, the nature of velocities and pressures in an axial flow pump is analysed. The comparisons are averaged flow velocities, static pressure rise, dynamic pressure and total pressure.nbs
DNA as a universal substrate for chemical kinetics
Molecular programming aims to systematically engineer molecular and chemical systems of autonomous function and ever-increasing complexity. A key goal is to develop embedded control circuitry within a chemical system to direct molecular events. Here we show that systems of DNA molecules can be constructed that closely approximate the dynamic behavior of arbitrary systems of coupled chemical reactions. By using strand displacement reactions as a primitive, we construct reaction cascades with effectively unimolecular and bimolecular kinetics. Our construction allows individual reactions to be coupled in arbitrary ways such that reactants can participate in multiple reactions simultaneously, reproducing the desired dynamical properties. Thus arbitrary systems of chemical equations can be compiled into real chemical systems. We illustrate our method on the Lotka–Volterra oscillator, a limit-cycle oscillator, a chaotic system, and systems implementing feedback digital logic and algorithmic behavior
Anopheles stephensi p38 MAPK signaling regulates innate immunity and bioenergetics during Plasmodium falciparum infection.
BackgroundFruit flies and mammals protect themselves against infection by mounting immune and metabolic responses that must be balanced against the metabolic needs of the pathogens. In this context, p38 mitogen-activated protein kinase (MAPK)-dependent signaling is critical to regulating both innate immunity and metabolism during infection. Accordingly, we asked to what extent the Asian malaria mosquito Anopheles stephensi utilizes p38 MAPK signaling during infection with the human malaria parasite Plasmodium falciparum.MethodsA. stephensi p38 MAPK (AsP38 MAPK) was identified and patterns of signaling in vitro and in vivo (midgut) were analyzed using phospho-specific antibodies and small molecule inhibitors. Functional effects of AsP38 MAPK inhibition were assessed using P. falciparum infection, quantitative real-time PCR, assays for reactive oxygen species and survivorship under oxidative stress, proteomics, and biochemical analyses.ResultsThe genome of A. stephensi encodes a single p38 MAPK that is activated in the midgut in response to parasite infection. Inhibition of AsP38 MAPK signaling significantly reduced P. falciparum sporogonic development. This phenotype was associated with AsP38 MAPK regulation of mitochondrial physiology and stress responses in the midgut epithelium, a tissue critical for parasite development. Specifically, inhibition of AsP38 MAPK resulted in reduction in mosquito protein synthesis machinery, a shift in glucose metabolism, reduced mitochondrial metabolism, enhanced production of mitochondrial reactive oxygen species, induction of an array of anti-parasite effector genes, and decreased resistance to oxidative stress-mediated damage. Hence, P. falciparum-induced activation of AsP38 MAPK in the midgut facilitates parasite infection through a combination of reduced anti-parasite immune defenses and enhanced host protein synthesis and bioenergetics to minimize the impact of infection on the host and to maximize parasite survival, and ultimately, transmission.ConclusionsThese observations suggest that, as in mammals, innate immunity and mitochondrial responses are integrated in mosquitoes and that AsP38 MAPK-dependent signaling facilitates mosquito survival during parasite infection, a fact that may attest to the relatively longer evolutionary relationship of these parasites with their invertebrate compared to their vertebrate hosts. On a practical level, improved understanding of the balances and trade-offs between resistance and metabolism could be leveraged to generate fit, resistant mosquitoes for malaria control
Simple guide to starting a research group
Conducting cutting-edge research and scholarship becomes more complicated with each passing year; forming a collaborative research group offers a way to navigate this increasing complexity. Yet many individuals whose work might benefit from the formation of a collaborative team may feel overwhelmed by the prospect of attempting to build and maintain a research group. We propose this simple guide for starting and maintaining such an enterprise
Clinical and echocardiographic characteristics and cardiovascular outcomes according to diabetes status in patients with heart failure and preserved ejection fraction. A report from the Irbesartan in Heart Failure with Preserved Ejection Fraction Trial (I-Preserve)
Background—In patients with HF and preserved ejection fraction (HFpEF), little is known about the characteristics of and outcomes in those with and without diabetes.
Methods—We examined clinical and echocardiographic characteristics and outcomes in the Irbesartan in Heart Failure with Preserved Ejection Fraction trial (I-Preserve), according to history of diabetes. Cox regression models were used to estimate hazard ratios (HR) for cardiovascular outcomes adjusted for known predictors, including age, sex, natriuretic peptides, and comorbidity. Echocardiographic data were available in 745 patients and were additionally adjusted for in supplementary analyses.
Results—Overall, 1134 of 4128 patients (27%) had diabetes. Compared to those without diabetes, they were more likely to have a history of myocardial infarction (28% vs. 22%), higher BMI (31kg/m2 vs. 29kg/m2), worse Minnesota living with HF score (48 vs. 40), higher median NT-proBNP concentration (403 vs 320 pg/ml; all p<0.01), more signs of congestion but no significant difference in LVEF. Patients with diabetes had a greater left ventricular (LV) mass and left atrial area than patients without diabetes. Doppler E wave velocity (86 vs 76 cm/sec, p<0.0001) and the ratio of E/e' (11.7 vs 10.4, p=0.010) were higher in patients with diabetes. Over a median follow-up of 4.1 years, cardiovascular death or HF hospitalization occurred in 34% of patients with diabetes vs. 22% of those without diabetes; adjusted HR 1.75 (95% CI 1.49-2.05) and 28% vs. 19% of patients with and without diabetes died; adjusted HR 1.59 (1.33-1.91).
Conclusions—In HFpEF, patients with diabetes have more signs of congestion, worse quality of life, higher NT-proBNP levels, and a poorer prognosis. They also display greater structural and functional echocardiographic abnormalities. Further investigation is needed to determine the mediators of the adverse impact of diabetes on outcomes in HFPEF, and whether they are modifiable
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