Optimal thermochemical material selection for a hybrid thermal energy storage system for low temperature applications using multi criteria optimization technique

Thermochemical energy storage is one of the viable solutions for the increasing energy demand because of its high energy density and less heat loss during the storage phase comparing to the other methods. The selection of proper thermochemical material (TCM) is then become important in this type of thermal energy storage. This paper describes the use of Multi Criteria Decision Making (MCDM) techniques to select the optimum thermochemical material from the alternatives to be used for low temperature (<150 °C) energy storage. The best thermochemical material is selected using different MCDM techniques like simple additive method, weighted product model, Technique for Order Preference by Similarity to Ideal Solution, Evaluation based on Distance from Average Solution, Multi-Objective Optimization on The Basis of Ratio Analysis, Preference Ranking Organization Method for Enrichment Evaluation, and VIKOR. The criteria weights for optimization are evaluated by different methods such as mean weight method, standard deviation method, analytic hierarchy process, Entropy method, criteria importance through inter-criteria correlation and Compromised weight method. In all MCDM-Weighting method combinations MgCl2·6H2O ranked first (optimum material) and Na2S·9H2O ranked last. The ranking obtained from various MCDM-weighting method combination are compared with each other using average Spearman rank correlation coefficient and found that Evaluation based on Distance from Average Solution (EDAS), Multi-Objective Optimization on The Basis of Ratio Analysis (MOORA), Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE II) and VIKOR with AHP weighting method have the highest correlation coefficient (rs = 0.9857) and CRITIC-VIKOR method (rs = 0.5143) has the lowest correlation coefficient

Efficacy and safety of metformin in the management of type 2 diabetes mellitus in older adults: a systematic review for the development of recommendations to reduce potentially inappropriate prescribing

BACKGROUND: Metformin is usually prescribed as first line therapy for type 2 diabetes mellitus (DM2). However, the benefits and risks of metformin may be different for older people. This systematic review examined the available evidence on the safety and efficacy of metformin in the management of DM2 in older adults. The findings were used to develop recommendations for the electronic decision support tool of the European project PRIMA-eDS. METHODS: The systematic review followed a staged approach, initially searching for systematic reviews and meta-analyses first, and then individual studies when prior searches were inconclusive. The target population was older people (≥65 years old) with DM2. Studies were included if they reported safety or efficacy outcomes with metformin (alone or in combination) for the management of DM2 compared to placebo, usual or no treatment, or other antidiabetics. Using the evidence identified, recommendations were developed using GRADE methodology. RESULTS: Fifteen studies were included (4 intervention and 11 observational studies). In ten studies at least 80% of participants were 65 years or older and 5 studies reported subgroup analyses by age. Comorbidities were reported by 9 studies, cognitive status was reported by 4 studies and functional status by 1 study. In general, metformin showed similar or better safety and efficacy than other specific or non-specific active treatments. However, these findings were mainly based on retrospective observational studies. Four recommendations were developed suggesting to discontinue the use of metformin for the management of DM2 in older adults with risk factors such as age > 80, gastrointestinal complaints during the last year and/or GFR ≤60 ml/min. CONCLUSIONS: On the evidence available, the safety and efficacy profiles of metformin appear to be better, and certainly no worse, than other treatments for the management of DM2 in older adults. However, the quality and quantity of the evidence is low, with scarce data on adverse events such as gastrointestinal complaints or renal failure. Further studies are needed to more reliably assess the benefits and risks of metformin in very old (>80), cognitively and functionally impaired older peopleThe PRIMA-eDS study was supported by a grant from the European Commission within the 7th Framework Programme (Grant No. 305388–2). The work of YVM was also supported by a grant from the NIHR Greater Manchester Primary Care Patient Safety Translational Research Centre. Publication of this article was funded by the UK National Institute for Health Research School for Primary Care Research, University of Mancheste