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Aromatherapy for dementia (Review)
Get PDFBackground
Medications licensed for the treatment of dementia have limited efficacy against cognitive impairment or against the distressed behaviours (behavioural and psychological symptoms, or behaviour that challenges) which are also often the most distressing aspect of the disorder for caregivers. Complementary therapies, including aromatherapy, are attractive to patients, practitioners and families, because they are perceived as being unlikely to cause adverse effects. Therefore there is interest in whether aromatherapy might offer a safe means of alleviating distressed behaviours in dementia.
Objectives
To assess the efficacy and safety of aromatherapy for people with dementia.
Search methods
We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register, on 5 May 2020 using the terms: aromatherapy, lemon, lavender, rose, aroma, alternative therapies, complementary therapies, essential oils. In addition, we searched MEDLINE, Embase, PsycINFO (all via Ovid SP), Web of Science Core Collection (via Thompson Web of Science), LILACS (via BIREME), CENTRAL (via the Cochrane Library), ClinicalTrials.gov and the World Health Organization (WHO) trials portal (ICTRP) on 5 May 2020.
Selection criteria
We included randomised controlled trials which compared fragrance from plants in an intervention defined as aromatherapy for people with dementia with placebo aromatherapy or with treatment as usual. All doses, frequencies and fragrances of aromatherapy were considered. Participants in the included studies had a diagnosis of dementia of any subtype and severity.
Data collection and analysis
Two reviewers independently selected studies for inclusion, extracted data and assessed risk of bias in included studies, involving other authors to reach consensus decisions where necessary. We did not perform any meta-analyses because of heterogeneity between studies, but presented a narrative synthesis of results from the included trials. Because of the heterogeneity of analysis methods and inadequate or absent reporting of data from some trials, we used statistical significance (P ≤ or > 0.5) as a summary metric when synthesising results across studies. As far as possible, we used GRADE methods to assess our confidence in the results of the trials, downgrading for risk of bias and imprecision.
Aromatherapy for dementia (Review) Copyright © 2020 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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Main results
We included 13 studies with 708 participants. All participants had dementia and in the 12 trials which described the setting, all were resident in institutional care facilities. Nine trials recruited participants because they had significant agitation or other behavioural and psychological symptoms in dementia (BPSD) at baseline. The fragrances used were lavender (eight studies); lemon balm (four studies); lavender and lemon balm, lavender and orange, and cedar extracts (one study each). For six trials, assessment of risk of bias and extraction of results was hampered by poor reporting. Four of the other seven trials were at low risk of bias in all domains, but all were small (range 18 to 186 participants; median 66), reducing our confidence in the results. Our primary outcomes were agitation, overall behavioural and psychological symptoms, and adverse effects. Ten trials assessed agitation using various scales. Among the five trials for which our confidence in the results was moderate or low, four trials reported no significant effect on agitation and one trial reported a significant benefit of aromatherapy. The other five trials either reported no useable data or our confidence in the results was very low. Eight trials assessed overall BPSD using the Neuropsychiatric Inventory and we had moderate or low confidence in the results of five of them. Of these, four reported significant benefit from aromatherapy and one reported no significant effect. Adverse events were poorly reported or not reported at all in most trials. No more than two trials assessed each of our secondary outcomes of quality of life, mood, sleep, activities of daily living, caregiver burden. We did not find evidence of benefit on these outcomes. Three trials assessed cognition: one did not report any data and the other two trials reported no significant effect of aromatherapy on cognition. Our confidence in the results of these studies was low.
Authors' conclusions
We have not found any convincing evidence that aromatherapy (or exposure to fragrant plant oils) is beneficial for people with dementia although there are many limitations to the data. Conduct or reporting problems in half of the included studies meant that they could not contribute to the conclusions. Results from the other studies were inconsistent. Harms were very poorly reported in the included studies. In order for clear conclusions to be drawn, better design and reporting and consistency of outcome measurement in future trials would be needed
Aerodynamic Analysis and Design of a Rim-Driven Fan for Fast Flight
Get PDFThis paper discusses the aerodynamic analysis and design of a novel, hubless, contra-rotating, rim-driven fan (RDF) device. Rim-driven thruster technology has been used for marine propulsion for decades, yet RDF technology has not been comparably developed for aerospace applications. This paper demonstrates that an innovative two-stage contra-rotating RDF configuration provides the potential for a significant increase in the available thrust and efflux velocity when compared with existing technologies. The analysis was conducted for an RDF device with a relatively small fan diameter of 120 mm. However, the findings of this study can be equally applied to the performance of much larger and more powerful RDF propulsion units. This would also include devices having multiple contra-rotating paired stages, for example, four, six, or more rotors to permit higher-pressure ratios and exhaust airspeeds suitable for large modern aircraft propulsion
A High Gain Flexible Antenna for Biomedical Applications
Get PDFIn this paper, a miniaturized antenna is presented for biomedical applications due to its flexibility. The proposed antenna operates in the Industrial, Medical, and Scientific (ISM) 24.00 GHz to 24.25 GHz band. This antenna consists of a radiating element with circular and rectangular slots and the ground with cross plus four square slots. The dielectric material Rogers RO3003 with permittivity of 3, is used for substrate and superstrate. The miniaturization of the antenna is achieved by shorting pin and some other techniques. The total volume of the designed antenna is (6.8×6.8×0.26) mm 3 . The maximum gain achieved by the simulation of the proposed antenna is 5.44 dB at 24.25 GHz, and at the start of the band, the gain is 4.9 dB at 23.98 GHz, and at the end of the band, the gain is 5.1 dB at 24.47 GHz. The designed antenna has better results than the antennas discussed in the literature in terms of size, gain, and efficiency
Variable structure controller for plastic injection moulding system
Get PDFThis paper discusses the approach to design of combined ANN and PID temperature controller for a plastic injection moulding system. The proposed method is based on integration of a conventional PID (PI) controller and a multilayer ANN. At the initial stage of operation, the ANN is trained in offline mode to approximately identify the dynamic parameters of the regulator optimised in terms of speed of response and overshoot. Under routine operation mode the ANN control structure is responsible for the fast transients whereas PID (PI) controller provides the high accuracy at the steady state condition. The paper focuses on the structure switching mechanism and the influence on the transient accuracy. In order to verify the proposed approach, the control system having various types of heaters has been modelled and simulated in Matlab/Simulink. The data obtained from the experiment verified the developed model and confirmed the results of simulations
A review of electrical motor topologies for aircraft propulsion
Get PDFThis paper provides a review of the state-of-the art in aircraft electrical propulsion (AEP). Initially, the limitations of on-board energy storage devices are highlighted and contextualised. The definitions of useful measures for determining the suitability of motor design, namely specific power and motor torque per unit rotor volume (TRW), are discussed and relevant examples are provided. The classifications of motors used for terrestrial vehicle applications are reviewed and their limitations highlighted regarding their suitability to AEP applications. A discussion on motor configurations for aerospace applications is provided which includes: synchronous motor stator winding configurations; axial flux motor configurations and the causes of energy losses. Additionally, the topologies and performance characteristics of existing aerospace motor technologies are examined. It was concluded that electrical motors provide an ideal means for achieving aircraft propulsion and that higher motor speeds are likely to be required for future commercial aircraft motor designs
Adapting existing behaviour: perceptions of substance switching and implementation of minimum pricing for alcohol in Wales
Get PDFMinimum Pricing for Alcohol (MPA) was enacted in Wales on March 2nd 2020. During the legislative process (i.e. consultation and parliamentary discussion), concern was expressed about the possibility of some drinkers switching to using other substances in response to any rise in the cost of alcohol. This paper reports on findings from a study which explored these pre-implementation concerns and how the policy was shaped. The research involved surveys (n=193) and interviews (n=87) with drinkers (predominantly harmful or treatment seeking) and providers of services. Survey responses were detailed, thus when combined with the interviews, provided a wealth of qualitative data, which are drawn upon in this paper. The findings highlight an expectation that most drinkers would respond to the new policy with adaptations of their coping mechanisms to maintain alcohol use at pre-legislative levels. This was either by switching alcohol products and adjusting their lifestyle to maintain an affordable drinking habit or developing new behaviours to manage additional costs. A small group of those with previous experience of drug use were identified as likely to switch from using alcohol to some other substances. Prior to the legislation being implemented awareness of the detail of the policy was found to be low, and perceptions of increased potential harm for certain groups were linked to concern about a lack of treatment capacity
Optimum performance determination of single-stage and dual-stage (contra-rotating) rim driven fans for electric aircraft
Get PDFElectrical Rim Driven Fan (RDF) technology is a novel application to aircraft propulsion, and there are many factors that play a part in determining its optimal achievable performance, for example, the electrical, magnetic and thermal properties of the rim driven motor architectures; the mechanical strength, mass and friction properties of the materials used; the aerodynamics of the fans and the efficiency of the motor drive and control circuitries. Each of these factors could easily warrant their own lengthy and in-depth analyses. The aims of this paper are to provide a starting point from which to get a feel for the rough-order-magnitude of an RDFs performance and to elucidate a conventional calculative methodology suitable for a quick and easy reality-check before undertaking more accurate numerical analysis techniques. Initially, the properties of an existing aerospace fan design, namely that of the IAE V2500-A5 turbo-fan engine, is used to validate this approach and then the same methodology is used to estimate a first-guess performance prediction for a range of single-stage RDFs of varying sizes from 100mm to 500mm diameter, operating over a range of speeds from zero to 25 kRPM. Finally, a comparison between a single-stage and a dual-stage (contra-rotating) 200mm diameter RDF for a UAV application is conducted. The performance limits of the RDFs considered in this analysis have been established to ensure that the fan blades are always operating within the subsonic flow regime
Thin CdTe layers deposited by a chamberless inline process using MOCVD, simulation and experiment
Get PDFThe deposition of thin Cadmium Telluride (CdTe) layers was performed by a chamberless metalorganic chemical vapour deposition process, and trends in growth rates were compared with computational fluid dynamics numerical modelling. Dimethylcadmium and diisopropyltelluride were used as the reactants, released from a recently developed coating head orientated above the glass substrate (of area 15 × 15 cm2). Depositions were performed in static mode and dynamic mode (i.e., over a moving substrate). The deposited CdTe film weights were compared against the calculated theoretical value of the molar supply of the precursors, in order to estimate material utilisation. The numerical simulation gave insight into the effect that the exhaust’s restricted flow orifice configuration had on the deposition uniformity observed in the static experiments. It was shown that > 59% of material utilisation could be achieved under favourable deposition conditions. The activation energy determined from the Arrhenius plot of growth rate was ~ 60 kJ/mol and was in good agreement with previously reported CdTe growth using metalorganic chemical vapour deposition (MOCVD). Process requirements for using a chamberless environment for the inline deposition of compound semiconductor layers were presented
Performance comparison between copper and aluminium windings in a rim driven fan for a small unmanned aircraft application
Get PDFRim Driven Fans (RDFs) are receiving increased attention amongst zero-emission aerospace technologists as they offer the potential for high Fan Pressure Ratios (FPR) to be efficiently generated and fan flow to be maximised compared with conventional (hub driven) electrical axial-flow fans. In other words; RDFs can provide higher thrust performance and exhaust air velocities than hub driven devices of the same intake area and also offer significant aerodynamic drag reductions. As such they are a feasible propulsion contender for fixed-wing, distributed-thrust, electrical aircraft designs. Thrust-to-weight ratio is a critical design parameter when considering aircraft propulsion devices and so design mass must be optimised accordingly. This paper presents an electromagnetic comparison of copper versus aluminium, slot-less, brushless DC motor (BLDC), stator-wiring architectures. The results of this study identify the performance benefits and limitations of these differing stator wiring materials in the context of a single rotor-stage RDF intended for the propulsion of a small unmanned aircraft
An Energy Efficient Service Composition Mechanism Using a Hybrid Meta-heuristic Algorithm in a Mobile Cloud Environment
Get PDFBy increasing mobile devices in technology and human life, using a runtime and mobile services has gotten more complex along with the composition of a large number of atomic services. Different services are provided by mobile cloud components to represent the non-functional properties as Quality of Service (QoS), which is applied by a set of standards. On the other hand, the growth of the energy-source heterogeneity in mobile clouds is an emerging challenge according to the energy saving problem in mobile nodes. In order to mobile cloud service composition as an NP-Hard problem, an efficient selection method should be taken by problem using optimal energy-aware methods that can extend the deployment and interoperability of mobile cloud components. Also, an energy-aware service composition mechanism is required to preserve high energy saving scenarios for mobile cloud components. In this paper, an energy-aware mechanism is applied to optimize mobile cloud service composition using a hybrid Shuffled Frog Leaping Algorithm and Genetic Algorithm (SFGA). Experimental results capture that the proposed mechanism improves the feasibility of the service composition with minimum energy consumption, response time, and cost for mobile cloud components against some current algorithms