Feed-forward observer-based intermittent fault detection

This paper provided an approach to design feed-forward observer for nonlinear systems with Lipchitz nonlinearity and bounded unknown inputs (disturbances/uncertainties) to ensure the sensitivity against intermittent faults. The proposed observer design guarantees the system error stability. Some variables and scalars are also introduced to design observer's parameters, which bring more degrees of flexibility available to the designer. The designed observer is used to propose a precision fault detection scheme including adaptive threshold design to detect intermittent faults. The efficiency of the considered approach is examined by the intermittent failure case in the suspension system of a vehicle. Simulation results show that the accurate state estimation and fault detection are achieved successfully

Feed-forward observer-based intermittent fault detection

This paper provided an approach to design feed-forward observer for nonlinear systems with Lipchitz nonlinearity and bounded unknown inputs (disturbances/uncertainties) to ensure the sensitivity against intermittent faults. The proposed observer design guarantees the system error stability. Some variables and scalars are also introduced to design observer's parameters, which bring more degrees of flexibility available to the designer. The designed observer is used to propose a precision fault detection scheme including adaptive threshold design to detect intermittent faults. The efficiency of the considered approach is examined by the intermittent failure case in the suspension system of a vehicle. Simulation results show that the accurate state estimation and fault detection are achieved successfully

Enhancing service requirements of technical product-service systems

Due to the integration of product and services as a new business model, product reliability and strategies for cost reduction at the early design stage have become important factors for many manufacturing firms. It is, therefore, critical at this phase to analyse the risk involved with Service Requirements noncompliance in order to help designers make informed decisions; as these decisions have a large impact on the Product Life Cycle (PLC). An investigation has been performed into how Service Requirements are analysed in a service orientated business to achieve reduced Life Cycle Cost (LCC) and improvements of existing Service Requirements. Weibull distribution and Monte Carlo principle have been proposed to do so; as they are considered as the most widely used in product reliability studies in the industry sector. A generic methodology for risk evaluation of failure to deliver a new product against Service Requirements is presented in this paper. This is part of the ongoing research project which aims to, apart from comparing current and targeted Service Requirements, it also facilitates an optimisation of them at the minimum risk of nonconformity

An integrated aerospace requirement setting and risk analysis tool for life cycle cost reduction and system design improvement

In the early conceptual stage of the service orientated model, decisions regarding the design of a new technical product are largely influenced by Service Requirements. Those decisions, therefore, have to merge both technical and business aspects to obtain desired product reliability and reduced Whole Life Cost (WLC). It is, therefore, critical at that phase to define the risk of potential noncompliance of Service Requirements in order to ensure the right design choices; as these decisions have a large impact on the overall product and service development. This paper presents outcome of research project to investigate different approaches used by companies to analyse Service Requirements to achieve reduced Life Cycle Cost (LCC). Analysis using Weibull distribution and Monte Carlo principle have been proposed here; based on the conducted literature review these are considered as the most widely used techniques in product reliability studies. Based on those techniques, a methodology and its software tool for risk evaluation of failure to deliver a new product against Service Requirements are presented in this paper. This is part of the on-going research project which, apart from analysing the gap between the current Service Requirements achievements and the design targets for a new aircraft engine, it also facilitates an optimisation of those requirements at the minimum risk of nonconformity

An aerospace requirements setting model to improve system design

Decisions at an early conceptual stage of the product lifecycle, are made with relatively low confidence, but such decisions greatly influence the overall product and service development. It is, therefore, critical to define the risks involved in order to help designers to make informed decisions. This research project investigates the risk and uncertainties in delivering products to meet top-level business requirements. The aim is to improve the existing process of setting business requirements and the current design approaches to achieve an optimised system design. This project also examines different approaches in assessing the risk of product and service delivery. To achieve that, a dedicated software tool, based on Weibull distribution function reliability model, has been created. An example of Rolls-Royce Civil Large Engine (CLE) gas turbine design process is used in this research as the case study. An analysis of the gap between the current design achievements and the targeted business requirements of a new product is performed at whole engine, module and component level. Further comparison of the new product business requirements, the novelty in the design and the historical reliability data is used to define and assess the risk of new product delivery

Neoadjuvant radiotherapy and anastomosis dehiscence after total mesorectal excision for stage II and III rectal cancer

SummaryBackgroundAnterior resection is nowadays the preferred option of surgical treatment for rectal cancer without sphincter involvement. However, this operation is associated with the risk of anastomosis dehiscence (AD).AimThe aim of this study was to estimate the influence of neoadjuvant radiotherapy and other factors on the risk of anastomosis dehiscence after total mesorectal excision for stage II and III rectal cancer.Materials/MethodsOne hundred and thirty consecutive patients operated on due to histologically confirmed rectal carcinoma were studied with prospective data collection. Elective surgery with curative intent was administered. All patients underwent sphincter-sparing anterior resection with total mesorectal excision. End-to-end anastomosis with double stapled technique was performed. Impact of patient-, tumour- and treatment-related variables on anastomosis dehiscence rate was evaluated in univariate and multivariate analysis.ResultsIncidence of AD was 10.6%. There was no leakage-related mortality. Univariate analysis showed that patient's age and gender, presence of lymph node metastases and irradiation setting (pre- vs post-operative) did not significantly influence dehiscence rate (P>0.05). Tumour level at or below 7cm from the anal verge was related to increased AD risk with statistical importance (P=0.0438). Neither pelvic drainage nor omentoplasty effectively protected the anastomosis. Proximal diversion with protective stoma resulted in significantly decreasing AD risk (P=0.0012). In multivariate analysis the presence of transversostomy was found as the most important factor independently associated with significantly lower incidence of AD.ConclusionsNeoadjuvant radiotherapy does not seem to be a significant risk factor for anastomosis dehiscence, even after resection of low-sited tumours, but proximal diversion with temporary stoma needs to be considered

Genetic characterization of antithrombin, protein C and protein S deficiencies in Polish patients

Inherited deficiencies of natural anticoagulants such as antithrombin (AT; gene: SERPINC1), protein C (PC; PROC), and protein S (PS; PROS1), with the prevalence in the general European population of 0.02% to 0.17%, 0.2% to 0.3%, and 0.5%, respectively, are associated with increased risk of thromboembolic events. Only a few case reports of Polish deficient patients with known causal mutations have been published so far. The aim of the study was to characterize the frequency of SERPINC1, PROC, and PROS1 mutations and their thromboembolic manifestations in patients with AT, PC, or PS deficiencies, inhabiting southern Poland. Ninety unrelated patients (mean [SD] age, 40.1 [13.2] years) with AT (n = 35), PC (n = 28), or PS (n = 27) deficiencies, with a history of venous 73 (81%) or arterial 17 (19%) thromboembolism, were screened for mutations using the Sanger sequencing or multiplex ligation‑dependent probe amplification. Twenty mutations (29%) described here were new, mostly in the SERPINC1 and PROC genes. Missense mutations accounted for 84% of all mutations in the PROC gene and approximately 50% of those in the SERPINC1 and PROS1 genes. In all 3 genes, the ratio of nonsense and splice-site mutations was 8% to 31% and 8% to 23%, respectively. The mutation detection rate was 90% for AT or PC when anticoagulant activity was below 70%, while for the PROS1 gene, the rate reached 80% at the free PS levels below 40%. To our knowledge, this is the largest cohort of Polish patients deficient in natural anticoagulants and evaluated for the causal genetic background. Several new Polish detrimental mutations were detected, mostly in AT- and PC‑deficient patients

Neoadjuvant radiotherapy and anastomosis dehiscence after total mesorectal excision for stage II and III rectal cancer

BackgroundAnterior resection is nowadays the preferred option of surgical treatment for rectal cancer without sphincter involvement. However, this operation is associated with the risk of anastomosis dehiscence (AD).AimThe aim of this study was to estimate the influence of neoadjuvant radiotherapy and other factors on the risk of anastomosis dehiscence after total mesorectal excision for stage II and III rectal cancer.Materials/MethodsOne hundred and thirty consecutive patients operated on due to histologically confirmed rectal carcinoma were studied with prospective data collection. Elective surgery with curative intent was administered. All patients underwent sphincter-sparing anterior resection with total mesorectal excision. End-to-end anastomosis with double stapled technique was performed. Impact of patient-, tumour- and treatment-related variables on anastomosis dehiscence rate was evaluated in univariate and multivariate analysis.ResultsIncidence of AD was 10.6%. There was no leakage-related mortality. Univariate analysis showed that patient's age and gender, presence of lymph node metastases and irradiation setting (pre- vs post-operative) did not significantly influence dehiscence rate (P>0.05). Tumour level at or below 7cm from the anal verge was related to increased AD risk with statistical importance (P=0.0438). Neither pelvic drainage nor omentoplasty effectively protected the anastomosis. Proximal diversion with protective stoma resulted in significantly decreasing AD risk (P=0.0012). In multivariate analysis the presence of transversostomy was found as the most important factor independently associated with significantly lower incidence of AD.ConclusionsNeoadjuvant radiotherapy does not seem to be a significant risk factor for anastomosis dehiscence, even after resection of low-sited tumours, but proximal diversion with temporary stoma needs to be considered

SARS-CoV-2 antibody response after mRNA vaccination in healthcare workers with and without previous COVID-19, a follow-up study from a university hospital in Poland during 6 months 2021

IntroductionHealthcare workers (HCWs) from the beginning of the pandemic have been at risk of exposure to SARS-CoV-2, so they were vaccinated as first.ObjectivesThe purpose of the study was to determine the level of antibodies against SARS-CoV-2 in HCWs before and after vaccination with mRNA preparations according to previous COVID- 19.Patients and methodsThe HCWs from the University Hospital in Krakow completed two surveys: the baseline survey before receiving the first dose of vaccine (in January 2021) and the follow-up survey in June 2021. In parallel, two blood samples were collected from each participant at baseline and at follow-up. Total anti-SARS-CoV-2 antibody levels were measured using the ECLIA technique.ResultsAt baseline, 41.1% of HCWs had positive antibody test results, and at follow-up, the vaccinated HCWs had almost 100 times higher antibody levels than the unvaccinated HCWs. Participants under 30 years of age had significantly higher antibody levels in June than older HCWs. Among participants with positive antibody test results in January, HCWs who had experienced asymptomatic COVID-19 had more than five times higher antibody levels in June than HCWs self-reported severe COVID-19. In total, 86.9% of HCWs received Comirnaty or Spikevax. The incidence rate of COVID-19 in the unvaccinated vs. vaccinated group was 13 times higher, 20.5% and 1.9% respectively.ConclusionsThese results confirm the effectiveness of vaccination in the prevention of COVID-19 in HCWs. It is worth getting vaccinated regardless of previous infection. Furthermore, vaccination among HCWs under 30 years of age induced more effective antibody production compared to older individuals

Wytyczne profilaktyki przeciwzakrzepowej u chorych onkologicznych, ze szczególnym uwzględnieniem pacjentów leczonych operacyjnie

Żylna choroba zakrzepowo-zatorowa (ŻChZZ), mimo że często występuje na różnych etapach rozwoju procesu nowotworowego, stanowi ciągle niedoceniany problem w populacji chorych onkologicznych. Terapia przeciwnowotworowa, zabiegi operacyjne czy znacznego stopnia zaawansowanie choroby nowotworowej to tylko niektóre czynniki ryzyka ŻChZZ, stanowiącej nadal jedną z najczęstszych przyczyn zgonu w populacji pacjentów onkologicznych. Zróżnicowanie ryzyka wystąpienia zakrzepicy żył głębokich (ZŻG) oraz ryzyka powikłań, w tym powikłań krwotocznych, pomiędzy poszczególnymi grupami chorych onkologicznych sugeruje przeprowadzenie indywidualnej oceny ryzyka i postępowanie profilaktyczne zależne od sytuacji klinicznej konkretnego pacjenta. Uzasadnia to także stałą aktualizację wytycznych postępowania profilaktycznego proponowanego chorym onkologicznym. W dokumencie przedstawiono oparte na przeglądzie piśmiennictwa zasady postępowania profilaktycznego w populacji chorych onkologicznych, ze szczególnym uwzględnieniem profilaktyki przeciwzakrzepowej w dyscyplinach zabiegowych