Supporting group maintenance through prognostics-enhanced dynamic dependability prediction

Condition-based maintenance strategies adapt maintenance planning through the integration of online condition monitoring of assets. The accuracy and cost-effectiveness of these strategies can be improved by integrating prognostics predictions and grouping maintenance actions respectively. In complex industrial systems, however, effective condition-based maintenance is intricate. Such systems are comprised of repairable assets which can fail in different ways, with various effects, and typically governed by dynamics which include time-dependent and conditional events. In this context, system reliability prediction is complex and effective maintenance planning is virtually impossible prior to system deployment and hard even in the case of condition-based maintenance. Addressing these issues, this paper presents an online system maintenance method that takes into account the system dynamics. The method employs an online predictive diagnosis algorithm to distinguish between critical and non-critical assets. A prognostics-updated method for predicting the system health is then employed to yield well-informed, more accurate, condition-based suggestions for the maintenance of critical assets and for the group-based reactive repair of non-critical assets. The cost-effectiveness of the approach is discussed in a case study from the power industry

Amyloid‐beta induces different expression pattern of tissue transglutaminase and its isoforms on olfactory ensheathing cells: Modulatory effect of indicaxanthin

Herein, we assessed the effect of full native peptide of amyloid‐beta (Aβ) (1‐42) and its fragments (25‐35 and 35‐25) on tissue transglutaminase (TG2) and its isoforms (TG2‐Long and TG2‐ Short) expression levels on olfactory ensheathing cells (OECs). Vimentin and glial fibrillary acid protein (GFAP) were also studied. The effect of the pre‐treatment with indicaxanthin from Opuntia ficus‐indica fruit on TG2 expression levels and its isoforms, cell viability, total reactive oxygen species (ROS), superoxide anion (O2−), and apoptotic pathway activation was assessed. The levels of Nestin and cyclin D1 were also evaluated. Our findings highlight that OECs exposure to Aβ(1‐ 42) and its fragments induced an increase in TG2 expression levels and a different expression pattern of its isoforms. Indicaxanthin pre‐treatment reduced TG2 overexpression, modulating the expression of TG2 isoforms. It reduced total ROS and O2− production, GFAP and Vimentin levels, inhibiting apoptotic pathway activation. It also induced an increase in the Nestin and cyclin D1 expression levels. Our data demonstrated that indicaxanthin pre‐treatment stimulated OECs self-renewal through the reparative activity played by TG2. They also suggest that Aβ might modify TG2 conformation in OECs and that indicaxanthin pre‐treatment might modulate TG2 conformation, stimulating neural regeneration in Alzheimer’s disease

A cost-benefit approach for the evaluation of prognostics-updated maintenance strategies in complex dynamic systems

The implementation of maintenance strategies which integrate online condition data has the potential to increase availability and reduce maintenance costs. Prognostics techniques enable the implementation of these strategies through up-to-date remaining useful life estimations. However, a cost-benefit assessment is necessary to verify the scale of potential benefits of condition-based maintenance strategies and prognostics for a given application. The majority of prognostics applications focus on the evaluation of a specific failure mode of an asset. However, industrial systems are comprised of different assets with multiple failure modes, which in turn, work in cooperation to perform a system level function. Besides, these systems include time-dependent events and conditional triggering events which cause further effects on the system. In this context not only are the system-level prognostics predictions challenging, but also the cost-benefit analysis of condition-based maintenance policies. In this work we combine asset prognostics predictions with temporal logic so as to obtain an up-to-date system level health estimation. We use asset level and system level prognostics estimations to evaluate the cost-effectiveness of alternative maintenance policies. The application of the proposed approach enables the adoption of conscious trade-off decisions between alternative maintenance strategies for complex systems. The benefits of the proposed approach are discussed with a case study from the power industry

Improved dynamic dependability assessment through integration with prognostics

The use of average data for dependability assessments results in a outdated system-level dependability estimation which can lead to incorrect design decisions. With increasing availability of online data, there is room to improve traditional dependability assessment techniques. Namely, prognostics is an emerging field which provides asset-specific failure information which can be reused to improve the system level failure estimation. This paper presents a framework for prognostics-updated dynamic dependability assessment. The dynamic behaviour comes from runtime updated information, asset inter-dependencies, and time-dependent system behaviour. A case study from the power generation industry is analysed and results confirm the validity of the approach for improved near real-time unavailability estimations

Supporting group maintenance through prognostics-enhanced dynamic dependability prediction

Condition-based maintenance strategies adapt maintenance planning through the integration of online condition monitoring of assets. The accuracy and cost-effectiveness of these strategies can be improved by integrating prognostics predictions and grouping maintenance actions respectively. In complex industrial systems, however, effective condition-based maintenance is intricate. Such systems are comprised of repairable assets which can fail in different ways, with various effects, and typically governed by dynamics which include time-dependent and conditional events. In this context, system reliability prediction is complex and effective maintenance planning is virtually impossible prior to system deployment and hard even in the case of condition-based maintenance. Addressing these issues, this paper presents an online system maintenance method that takes into account the system dynamics. The method employs an online predictive diagnosis algorithm to distinguish between critical and non-critical assets. A prognostics-updated method for predicting the system health is then employed to yield well-informed, more accurate, condition-based suggestions for the maintenance of critical assets and for the group-based reactive repair of non-critical assets. The cost-effectiveness of the approach is discussed in a case study from the power industry

Synthesis and biological evaluation of phosphonated dihydroisoxazole nucleosides

Phosphonated isoxazolinyl nucleosides have been prepared via 1,3-dipolar cycloaddition reaction of nitrile oxides with corresponding vinyl or allyl nucleobases for antiviral studies. The cytotoxicity, the anti-HSV activity and the RT-inhibitory activity of the obtained compounds were evaluated and compared with those of AZT and diethyl{(10SR,40RS)-10-[[(5-methyl-2,4-dioxo-3,4- dihydropyrimidin-1(2H)-yl)]-30-methyl-20-oxa-30-azacyclopent-40-yl]}methylphosphonate, a saturated phosphonated dihydroisoxazole nucleoside analogue

Novel 3,3-disubstituted oxindole derivatives. Synthesis and evaluation of the anti-proliferative activity

3,3-Disubstituted oxindole derivatives bearing a nitrogen atom at the C-3 position have been synthesized starting from 3-alkyl oxindole through a metal free pathway. These derivatives have been tested in five human tumor cell lines (PC3, MCF7, SW620, MiaPaca2 and A375) and on primary cells (PBMCs) from healthy donors providing compound 6d showing a strong anticancer effect in all cancer lines on the low micromolar range

Onychomycosis: Recommendations for Diagnosis, Assessment of Treatment Efficacy, and Specialist Referral. The CONSONANCE Consensus Project

Introduction: Onychomycosis is the most common nail disorder in adults, with high recurrence and relapse rates. Its diagnosis may be difficult by non-experts because the clinical signs may overlap with other dermatoses. The treatment may be challenging, as it should be patient-tailored. Methods: An online survey was conducted among European Nail Society (ENS) members to provide recommendations on the diagnosis and assessment of distal lateral subungual onychomycosis (DLSO) in non-specialized clinical environments, as well as recommendations for patient referral. Results: DLSO diagnosis is predominantly based on clinical aspects, and microscopy and fungal culture are commonly employed to establish the diagnosis. Assessment of clinical features is the main method for DLSO follow-up, and the main criterion to define cure is a combination of mycologic cure and clinical cure. The most commonly selected treatments for onychomycosis include oral antifungals, topical antifungals, and nail debridement. According to the nail experts, predisposing factors of DLSO to be evaluated include concurrent tinea pedis diagnosis, immunocompromised status, and diabetes. The minimum clinical aspects to be evaluated for DLSO diagnosis should include subungual hyperkeratosis, white-yellow-orange subungual scales, and absence of salmon-pink coloration. Recommendations for clinical signs that should be evaluated to confirm treatment effectiveness include normal appearance and color of the nail, reduction or absence of scales under the nail, and absence of onycholysis. Recommendations for specialist referral include lack of treatment effectiveness, need of additional therapies, concurrent presence of other diseases or comorbidities, severe DLSO, and presence of a dermatophytoma or involvement of the nail matrix. Conclusions: According to the surveyed nail experts, after evaluating clinical signs and predisposing factors for DLSO, the diagnosis should include subungual hyperkeratosis, nail color (yellow-orange), and onycholysis and thickening. In cases of severe DLSO, when there is treatment failure, concomitant diseases/comorbidities, presence of a dermatophytoma or involvement of the nail matrix, or involvement of several/all nails, referral should be considered