118 research outputs found

    Numerical Investigation on Turbulent Non-premixed Methanol Flames Using Conditional Source-term Estimation

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    Conditional Source-term Estimation (CSE) is a turbulent combustion model that uses conditional averages to close the chemical source term. Previous CSE studies have shown that the model is able to predict the flame characteristics successfully, however, these studies have only focused on simple hydrocarbon fuels mostly composed of methane. The objective of the present study is to evaluate the capabilities of CSE applied to turbulent non-premixed methanol flames, which has never been done previously. The present study investigates two different types of methanol flames: piloted and bluff -body flames. For the piloted flame, the standard k-ϵ model is used for turbulence modelling, while the Shear Stress Transport (SST) k-ω model is used in the bluff-body case. Different values of empirical constants within the turbulence models are tested, and C_ϵ1 = 1:7 for the piloted flame and γ_2 = 0:66 for the bluff -body flame provide the most comparable predictions of mixing field to the experimental measurements. Detailed chemistry mechanism, GRI MECH 2.11, is included in tabulated form using the Trajectory Generated Low Dimensional Manifold (TGLDM) method. The predictions including both the Favre averaged and conditional mass fractions of the reactive species and temperature are compared with available experimental data and previous numerical results. Overall, the predictions by CSE for both the conditional and unconditional quantities are in a good agreement with the experimental data except for H_2. Sources of discrepancies are identified such as the chemical kinetics and neglect of differential diffusion. Large Eddy Simulations may help to improve the velocity and mixing field predictions

    Optimal Policy Combinations of Abatement Subsidy and Pollution Tax in Vertical Oligopolies

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    AbstractThis article investigates environmental regulations on eco-industry in vertical oligopolies, in which the upstream industry produces abatement goods reducing pollutants and the downstream industry produces consumption goods emitting pollutants. We devise the optimal combination of appropriate policy instruments and show that an optimal pollution tax should be used for the negative externality and output restrictions in final production, and an optimal abatement subsidy should incorporate the effect of upstream market restrictions on abatement activity. We also examine the welfare effect of the subsidy policy on the abatement technology in tax/subsidy combination

    The Effectiveness of Moxibustion: An Overview During 10 Years

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    Moxibustion has been used to treat various types of disease. However, there is still insufficient evidence regarding its effectiveness. This study was performed to summarize and evaluate the effectiveness of moxibustion. A search was performed for all randomized controlled trials in PubMed between January 1998 and July 2008 with no language restriction. The results yielded 47 trials in which six moxibustion types were applied to 36 diseases ranging from breech presentation to digestive disorders. Moxibustion was compared to three types of control group: general care, Oriental medical therapies or waiting list. Moxibustion was superior to the control in 14 out of 54 control groups in 46 studies. There were no significant differences among groups in 7 studies, and the outcome direction was not determined in 33 studies. Seven studies were included in a meta-analysis. Moxibustion was more effective than medication in two ulcerative colitis studies (relative risk (95% CI), 2.20 (1.37, 3.52), P = .001, I2 = 0%). Overall, our results did not support the effectiveness of moxibustion in specific diseases due to the limited number and low quality of the studies and inadequate use of controls. In order to provide appropriate evidence regarding the effectiveness of moxibustion, more rigorous clinical trials using appropriate controls are warranted

    Does Acupuncture Protect Dopamine Neurons in Parkinson's Disease Rodent Model?: A Systematic Review and Meta-Analysis

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    Background: Acupuncture has been reported to have significant effects, not only in alleviating impaired motor function, but also rescuing dopaminergic neuron deficits in rodent models of Parkinson's disease (PD). However, a systemic analysis of these beneficial effects has yet to be performed.Objective: To evaluate the neuroprotective effect of acupuncture in animal models of PD.Methods: A literature search of the PubMed, MEDLINE, EMBASE, China National Knowledge Infrastructure, Research Information Service System, and Japan Society of Acupuncture and Moxibustion databases was performed to retrieve studies that investigated the effects of acupuncture on PD. The quality of each included study was evaluated using the 10-item checklist modified from the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies. RevMan version 5.3 (Foundation for Statistical Computing, Vienna, Austria) was used for meta-analysis.Results: The 42 studies included scored between 2 and 7 points, with a mean score of 4.6. Outcome measures included tyrosine hydroxylase (TH) level and dopamine content. Meta-analysis results revealed statistically significant effects of acupuncture for increasing both TH levels (33.97 [95% CI 33.15–34.79]; p < 0.00001) and dopamine content (4.23 [95% CI 3.53–4.92]; p < 0.00001) compared with that observed in PD control groups. In addition, motor dysfunctions exhibited by model PD animals were also mitigated by acupuncture treatment.Conclusions: Although there were limitations in the number and quality of the included studies, results of this analysis suggest that acupuncture exerts a protective effect on dopaminergic neurons in rodent models of PD

    Acupuncture Enhances the Synaptic Dopamine Availability to Improve Motor Function in a Mouse Model of Parkinson's Disease

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    Parkinson's disease (PD) is caused by the selective loss of dopaminergic neurons in the substantia nigra (SN) and the depletion of striatal dopamine (DA). Acupuncture, as an alternative therapy for PD, has beneficial effects in both PD patients and PD animal models, although the underlying mechanisms therein remain uncertain. The present study investigated whether acupuncture treatment affected dopamine neurotransmission in a PD mouse model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We found that acupuncture treatment at acupoint GB34 improved motor function with accompanying dopaminergic neuron protection against MPTP but did not restore striatal dopamine depletion. Instead, acupuncture treatment increased dopamine release that in turn, may lead to the enhancement of dopamine availability in the synaptic cleft. Moreover, acupuncture treatment mitigated MPTP-induced abnormal postsynaptic changes, suggesting that acupuncture treatment may increase postsynaptic dopamine neurotransmission and facilitate the normalization of basal ganglia activity. These results suggest that the acupuncture-induced enhancement of synaptic dopamine availability may play a critical role in motor function improvement against MPTP

    From Peripheral to Central: The Role of ERK Signaling Pathway in Acupuncture Analgesia

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    Despite accumulating evidence of the clinical effectiveness of acupuncture, its mechanism remains largely unclear. We assume that molecular signaling around the acupuncture needled area is essential for initiating the effect of acupuncture. To determine possible bio-candidates involved in the mechanisms of acupuncture and investigate the role of such bio-candidates in the analgesic effects of acupuncture, we conducted 2 stepwise experiments. First, a genome-wide microarray of the isolated skin layer at the GB34-equivalent acupoint of C57BL/6 mice 1 hour after acupuncture found that a total of 236 genes had changed and that extracellular signal–regulated kinase (ERK) activation was the most prominent bio-candidate. Second, in mouse pain models using formalin and complete Freund adjuvant, we found that acupuncture attenuated the nociceptive behavior and the mechanical allodynia; these effects were blocked when ERK cascade was interrupted by the mitogen-activated protein kinase kinase (MEK)/mitogen-activated protein kinase (MAPK) inhibitor U0126 (.8 μg/μL). Based on these results, we suggest that ERK phosphorylation following acupuncture needling is a biochemical hallmark initiating the effect of acupuncture including analgesia

    Combined treatment with acupuncture reduces effective dose and alleviates adverse effect of l-dopa by normalizing Parkinson's disease-induced neurochemical imbalance

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    This study first showed the behavioural benefits of novel combination therapy of l-dopa with acupuncture on Parkinson’s disease, and its underlying mechanisms within basal ganglia. The previous study reported that acupuncture may improve the motor function of a Parkinson’s disease (PD) mouse model by increasing the dopamine efflux and turnover ratio of dopamine. Hence, we hypothesised that combining l-dopa with acupuncture would have a behavioural benefit for those with PD. We performed unilateral injections of 6-OHDA into the striatum of C57Bl/6 mice to model hemi-Parkinsonian attributes. To test motor function and dyskinetic anomalies, we examined cylinder behaviour and abnormal involuntary movement (AIM), respectively. We found that (1) a 50% reduced dose of l-dopa (7.5 mg/kg) combined with acupuncture showed an improvement in motor function that was comparable to mice given the standard dose of l-dopa treatment (15 mg/kg) only, and that (2) the combination treatment (l-dopa +acupuncture) was significantly superior in reducing AIM scores when equivalent doses of l-dopa were used. The combination treatment also significantly reduces the abnormal increase of GABA contents in the substantia nigra compared to the standard l-dopa treatment. Furthermore, abnormal expression of FosB, the immediate early gene of l-dopa induced dyskinesia (LID), was mitigated in the striatum by the combination treatment. All of these results indicate that acupuncture enhances the benefits of l-dopa on motor function with reduced dose of l-dopa and alleviating LID by normalising neurochemical imbalance within the basal ganglia
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