Classic Maintenance Research Articles

Immunosuppression Protocols in Intestinal and Multivisceral Transplantation—A Literature Review

Intestinal transplantation (IT) and multivisceral transplantation (MVT) are curative therapies for patients with intestinal failure and severe complications associated with total parenteral nutrition. High levels of immunosuppression are required to prevent acute cellular rejection (ACR) from the bowel. Studies regarding pre-treatment, induction, and post-transplant therapy have improved graft acceptance, reducing immunosuppression doses and infectious complications. However, the low rate of IT and MVT and the small number of specialized centers have resulted in a limited number of evidence-based immunosuppression protocols. We reviewed immunosuppression in IT and MVT to draw useful conclusions regarding the best protocol strategies for the induction, maintenance, and management of ACR. A review was performed using the PubMed database. Articles on immunosuppression protocols in IT and MVT that addressed graft rejection, infection, or survival, published between 2006 and 2022, were selected. A total of 690 articles were selected. Two researchers applied the inclusion and exclusion criteria and selected 14 articles independently. For induction, thymoglobulin, alemtuzumab, and basiliximab are the most frequently used immunosuppressants for induction. Classic maintenance therapy consists of a combination of corticosteroids and tacrolimus. Methylprednisolone with an increased tacrolimus dose is used most frequently to manage ACR. Depending on the receptor response, such as thymoglobulin, infliximab, adalimumab, or bortezomib, other immunosuppressants should be considered. There have been great advances in IT and TMV immunosuppression. We conclude that the gold standard immunosuppressive protocol is triple therapy, comprising induction with thymoglobulin, maintenance with steroids for a few months, and tacrolimus and mycophenolate therapy. Innovative approaches for treating intestinal rejection episodes with more appropriate drugs, such as infliximab, adalimumab, or bortezomib, are necessary.

Proactive maintenance scheduling in consideration of imperfect repairs and production wait time

Wait time due to the exhaustion of raw materials or lack of demand is common in manufacturing/production processes, which provides cost-effective maintenance opportunities. This paper designs a two-phase opportunistic maintenance framework based on defect information, which integrates properties of production waits into the decision-making process. At the first phase, a finite number of inspections are executed to reveal the defective state, followed by imperfect preventive repair. At the second phase, no maintenance action is taken until reaching a scheduled maintenance window (postponed maintenance) or arrivals of production waits (opportunistic maintenance). The integration of imperfect repair with postponed and opportunistic maintenance enables a sufficient utilization of remaining useful lifetime and a flexible resource allocation. Under the constraint of the steady-availability requirement, the optimal policy minimizing the system maintenance cost is obtained via the genetic algorithm. A case study from a steel convertor plant shows that our policy outperforms some classic maintenance policies.

Diagnostic of Failure in Transmission System of Agriculture Tractors Using Predictive Maintenance Based Software

The expansion of services and technological equipment applied to the agribusiness sector grows year after year, e.g., tractors and agricultural machinery, which use systems shipped with sophisticated software that collaborate to aid, and optimize activities in the field. Maintenance of agricultural machinery, including tractors, is routine in the life of any farmer, especially the preventive and corrective maintenance. In this paper, the objective was to evaluate an alternative for the use of diagnostic software in the prediction of failures that may occur in the tractor clutch system. In this study, the PicoScope6 software was used to identify the failures in this system, and then, using the predictive maintenance phase, was compared with classic maintenance methods, allowed for estimating the necessary repair time. Results showed that software identified more precisely the mechanical components that presented failures. From the identification of failure components, a list of repairs and exchanges was estimated, and, when compared to the list of components generated by inspection without diagnostic software, the repair time was reduced by 88%, and the cost of repair in up to 93%. The availability of the equipment also increased as a result of the shorter repair time, thus maximizing the machine time in the field.

DEVELOPMENT OF BEE COLONIES BASED ON EARLY SPRING FEEDING ACCORDING TO THE DEVELOPED SCHEME

The strength and development of bee colonies in May, especially those that have weakened after wintering, is not sufficient for the effective use during the first honey harvest in Ukraine.One way to effectively stimulate bee colonies to develop is through the use of carbohydrate protein feedings.The purpose of the study was to investigate the development of bee colonies in the early spring with the use of different types of feeding.The studies were conducted using zootechnical (alignment and assessment of the status of bee colonies, control feeding) and statistical methods of research in the early spring of 2019 in the conditions of Holosiivskaapiary (Kyiv, Ukraine).The control group – classic maintenance, similar to all apiary colonies. The research group – was applied the developed scheme of early spring feeding and training of bees. For feeding, honey – beebread dough, bee pollen in the form of flour, monofloral bee pollen candy were used. After the first feeding, the experimental colonies outweighed the control ones by 0.3 rows in strength, 0.5 comb by the number of open brood combs and 0.43 comb by the sealed ones as well as by 1.3 comb of fodder (5.3 kg). After the second feeding, the experimental colonies outweighed the control ones by 1.6 rows in strength, 1.5 comb by the number of open brood combs, were the same by the number of sealed sells and outweighed by 0.3honeycomb in the number of fodder. During the evaluation it was found that the experimental colonies outweighed the controlled ones instrength by 2 rows, by 0.5 in open and by 1 comb in sealed brood combs as well as by 0.5 honeycomb of fodder (2 kg). It was found that a complex three-stage carbohydrate-protein feeding of weak bee colonies (5–6 combs) after wintering makes it possible to increase their strength to 10 combs by early May. Normal 0 false false false RU X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Обычная таблица"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

Optimal maintenance policy considering maintenance errors for systems operating under performance-based contracts

In recent years, performance-based contracts (PBCs) have been extensively adopted in both manufacturing and service industries. However, maintenance strategies under PBCs are not often addressed. This paper considers a novel maintenance policy for a single-component system operating under a PBC. Failures of this system may either be hard or soft, but can only be revealed by periodic inspection. Imperfect repair (subject to the virtual age model) is used to fix a soft failure. However, imperfect repair actions may be ineffective and could cause a catastrophic failure (maintenance error) that ultimately leads to replacement. In the model proposed in this paper, we consider maintenance error, and the system is replaced upon a hard failure, a maintenance error, or preventively replaced at the nth soft failure. The objective of this model is to maximize the expected net revenue of the supplier operating under a PBC. Moreover, we compare the properties of the optimal maintenance policy under three different failure rate functions and show that, with different parameters, our model reduces to several classic maintenance models. Finally, a case study on a wind turbine system is provided to illustrate the application of the maintenance model.

INDUSTRY 4.0: Predictive Intelligent Maintenance for Production Equipment

In manufacturing, users increasingly demand comprehensive maintenance service in their production equipment in order to ensure high availability and to prevent downtimes in critical phases of the production processes, affecting customer delivery times. From the manufacturer’s point of view, it is vital to optimize and to improve the service provided to the final users, allowing appropriate maintenance planning and responding to the demand. Contrary to the classic preventive maintenance programs in use today, predictive maintenance improves the performance of the equipment, strengthening the business model of companies. Thanks to the inclusion of a set of sensing, condition monitoring, predictive analytics and distribute systems technologies, it is possible to perform and provide a remote technical assistance based on continuous monitoring and maintenance support from a distance. This paper shows the benefits and advantages to be achieved by the development of a comprehensive predictive maintenance, through the concept of Industry 4.0, and focuses on remote monitoring and self-diagnosis function of health condition for the equipment. However, the main emphasis of the work presents the data acquisition and analysis processes to develop predictive algorithms for machines in production.

Prevalence of Virulence/Stress Genes in Campylobacter jejuni from Chicken Meat Sold in Qatari Retail Outlets.

Chicken meat from the shelves of supermarkets in Qatar was tested for the presence of Campylobacter spp. and the presence of five virulence genes (htrB, cdtB, clpP, cadF and ciaB) was assessed in isolates. Forty eight percent of the chickens provided for supermarkets by Saudi (53%) and Qatari (45.9%) producers were found to be contaminated and the most important factor affecting the overall prevalence of contaminated chickens was the store from which chicken samples originated. Variation in prevalence of Campylobacter in chicken meat from different stores was evident even when the same producer supplied the three stores in our survey. Differences in the prevalence and in the combinations of virulence genes in isolates that can and cannot grow in a classic maintenance medium (Karmali) were identified, providing a starting point for linking presence/absence of particular virulence genes with actual in vivo virulence and pathogenicity. Because of the relatively low infective doses of Campylobacter that are required to initiate infection in humans, it will be important to explore further the relationships we identified between certain Campylobacter virulence genes and their capacity for survival in poultry meat, and hence their contribution to the incidence of campylobacteriosis.

T(12;21)/ETV6 -RUNX1 Confers a Specific Pattern of In Vivo Sensitivity to Treatments in Childhood B-Cell Precursor Acute Lymphoblastic Leukemia (BCP-ALL): Results of the Randomized Trials 58881 and 58951 of the EORTC Children Leukemia Group

Background In childhood BCP-ALL, the presence of t(12;21)/ETV6 -RUNX1 defines one of the most prevalent oncogenic subgroup and is usually associated with a favorable outcome. Nevertheless, an excellent prognosis has not been reported by all collaborative groups, suggesting that the outcome of ETV6 -RUNX1 patients (pts) could be influenced by the treatment. To address this issue, the long-term outcome of ETV6 -RUNX1 pts was investigated into the EORTC 58881 and 58951 studies, with particular attention to the effect of the randomized treatments. Methods The 58881 study (1989-1998) used a BFM backbone without cranial irradiation, and aimed to compare E-Coli (Medac®) Asparaginase (A'ase) with Erwinia A'ase and to assess the value of 6-Mercaptopurine (6-MP) i.v. (1 g/m²/month) when added to classic maintenance. The subsequent 58951 study (1999-2008) used the best arm of the trial 58881, i.e. E-Coli A'ase and classic maintenance. The aims of this study were to compare dexamethasone (Dexa) (6 mg/m²/day) with prednisone (Pred) (60 mg/m²/day) during induction and maintenance; to evaluate increased number of A'ase administrations (24 vs 12) for non-very high risk pts; and to assess the value of vincristine/corticosteroid pulses during maintenance for average risk pts. Detection of ETV6 -RUNX1 by FISH and/or RT-PCR was centralized. Pts less than 1 year (yr) or with t(9;22)/BCR-ABL were excluded from the analysis. Results An ETV6 -RUNX1 was evidenced in 104/363 (28%) and 380/1493 (27%) newly diagnosed BCP-ALL pts enrolled in the 58881 and 58951 trial respectively. A majority of ETV6-RUNX1 pts were below the age of 10 yrs (93.3% in 58881 and 91.3% in 58951). The median follow-up was 11.8 yrs for the 58881 and 6.7 yrs for the 58951. In both studies, the 10-yr event-free-survival (EFS) rate was significantly higher for ETV6 -RUNX1 pts than for all BCP-ALL pts (82.5% vs 74.9% in 58881 and 90.8% vs 82.7% in 58951), and was similar to the 10-yr EFS of hyperdiploid pts. Noteworthy, very few EFS events were observed during treatment period or after 6 yrs from diagnosis. The main prognostic factors of the ETV6-RUNX1 subgroup in both studies were the white blood cell count (WBC) and the response to prephase. As shown in the table below, the analysis of the relationship between treatment modalities and outcome revealed that the in vivo drug sensitivity of ETV6-RUNX1 ALL was distinct from that of other BCP-ALL. In this subgroup, the benefit of a more potent A'ase (58881) or of intensified A'ase administrations (58951) was less pronounced as compared to other pts, and 6-MP i.v. during maintenance was particularly deleterious. Moreover, the overall benefit of vincristine/corticosteroid pulses was not observed in ETV6-RUNX1 average risk group pts, who already had an outstanding outcome. By contrast, the use of Dexa in place of Pred significantly improved the 10-yr EFS of ETV6-RUNX1 pts (95.0% vs 87.2%, hazard ratio (HR)=0.44, 95% CI 0.20-0.96) whereas no difference was observed in the remaining population (HR=1.01, 95% CI 0.77-1.33) (test for interaction: p=0.04). Table.5888158951All (n=363)ETV6-RUNX1 (n=104)Hyperdiploid (n=102)Others1 (n=155)All (n=1493)ETV6-RUNX1 (n=380)Hyperdiploid (n=484)Others1 (n=619)10-yr EFS ratesAll pts74.9%82.5%83.3%65.2%82.7%90.8%88.4%73.2%Pred ² (n=745)81.8%87.2%88.8%73.0%Dexa ² (n=748)83.6%95.0%88.0%73.5%Medac A'ase 2,3 (n=320)76.6%83.2%88.6%65.7%Other A'ase 2,3 (n=43)62.8%78.6%50.0%60.0%10-yr disease-free-survival ratesShort A'ase 4 (n=607)83.5%91.2%90.1%72.4%Long A'ase 4 (n=622)87.0%94.8%88.2%80.7%No 6-MP iv 2,5 (n=96)85.4%100%90.9%72.5%6-MP iv 2,5 (n=94)72.3%70.6%78.6%68.8%No Pulse 5,6 (n=148)87.5%96.1%88.5%71.1%Pulse 5,6 (n=153)82.8%95.1%91.3%82.3%1Others, MLL rearrangements excluded 2All risk groups 3Pts randomized or not for A'ase 4Non-very high risk pts 5Pts who started maintenance 6Average risk pts Conclusions Within the EORTC 58881 and 58951 trials, the use of Dexa rather than Pred allowed to further improved the long-term outcome for ETV6-RUNX1 pts. Our data also show that this excellent outcome can be jeopardized by slight changes in therapy, such as the addition of 6-MP i.v. to classic maintenance. Together, these results stress the importance of analyzing homogeneous oncogenetic subgroups when comparing different therapeutic schemes, to unmask specific drug effects that could be hidden when analyzing the whole group of patients. Disclosures Bertrand: ERYTECH Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees.

DNA methylation requires a DNMT1 ubiquitin interacting motif (UIM) and histone ubiquitination.

DNMT1 is recruited by PCNA and UHRF1 to maintain DNA methylation after replication. UHRF1 recognizes hemimethylated DNA substrates via the SRA domain, but also repressive H3K9me3 histone marks with its TTD. With systematic mutagenesis and functional assays, we could show that chromatin binding further involved UHRF1 PHD binding to unmodified H3R2. These complementation assays clearly demonstrated that the ubiquitin ligase activity of the UHRF1 RING domain is required for maintenance DNA methylation. Mass spectrometry of UHRF1-deficient cells revealed H3K18 as a novel ubiquitination target of UHRF1 in mammalian cells. With bioinformatics and mutational analyses, we identified a ubiquitin interacting motif (UIM) in the N-terminal regulatory domain of DNMT1 that binds to ubiquitinated H3 tails and is essential for DNA methylation in vivo. H3 ubiquitination and subsequent DNA methylation required UHRF1 PHD binding to H3R2. These results show the manifold regulatory mechanisms controlling DNMT1 activity that require the reading and writing of epigenetic marks by UHRF1 and illustrate the multifaceted interplay between DNA and histone modifications. The identification and functional characterization of the DNMT1 UIM suggests a novel regulatory principle and we speculate that histone H2AK119 ubiquitination might also lead to UIM-dependent recruitment of DNMT1 and DNA methylation beyond classic maintenance.

Perforation of peptic ulcer following abrupt cessation of long-term opiate use

Unaided and abrupt cessation of opiate use without drug substitution and step-down, referred to as "cold turkey," is a common and difficult process for substance users, and is associated with several withdrawal symptoms and complications. This report presents a preliminary series of patients treated at an urban public hospital with acute perforation of peptic ulcers following abrupt cessation of long-term opiate use, a phenomenon that has not been previously described in the literature. Thirty-five patients with acute gastroduodenal perforation and a history of opiate addiction with a recent and abrupt cessation of opiate use were admitted between February 2004 and October 2008. This study evaluated the demographics, antecedent drug use, substance use characteristics, previous medical or surgical treatment of peptic ulcer disease, and surgical findings. The mean age was 32.3 years (range, 21-41 years) and the patients were overwhelmingly male (94%). The most frequent agent in single opiate users was opium (62.9%) followed by heroin (22.9%). The time interval between opiate cessation and perforation onset was 2-65 days (mean, 6.1 days). All patients underwent an immediate exploratory laparotomy, and the majority of perforations were found to be in the postpyloric area (94%) with mean size of 4.3 x 5.1 mm. Two patients (6%) had perforations in the lesser curvature of the stomach. All of the perforations occurred following sudden self-cessation without step-down or classic maintenance therapy, and this may prove the importance of supervised medical detoxification with special attention to gastroprotective agents such as antacid drugs.

Special section on Web Systems Evolution

Evolution of Web applications is high for several reasons. Among the others, the need of being constantly updated with the emerging technologies is maybe the most important. Web Systems Evolution is a multifaceted and broad field studying techniques, approaches and tools able to restructure, re-engineer and in general modify a Web application with the intention of renovating or improving some quality aspects of it. This special section is devoted to a selection of papers that have been originally published in the proceedings of the International Symposium on Web Site Evolution, held in Beijing, China in October 2008. The selected papers investigate different issues concerning the evolution of Web Systems, ranging from migration towards SOA to more classic re-engineering and maintenance tasks (e.g., improving the navigational structure). The main contribution of this special section consist of translating some interesting research ideas about Web systems evolution into solutions and tools able to transfer knowledge to the industry.

Biomechanics of aggressive inline skating: Landing and balancing on a grind rail

Currently, only epidemiological injury data have been reported for the new extreme sport of aggressive inline skating, or trick skating. No studies have examined the biomechanics of this sport, which involves repetitive jumping and landing from railings, ramps, and ledges, often over 1 m in height. We present results of a pilot study that examined the effect of skater experience and lower extremity biomechanics on energy absorption ability, and observed balance strategies used during two basic tricks. In these tricks, the skater jumps onto an elevated rail and maintains balance while standing in a single position (stall) or sliding along the rail (grind). Lower extremity joint kinematics, impact force characteristics, and general movement behaviours were examined during landing and balance phases. Ten male skaters performed ten stalls and ten frontside grinds on an instrumented grind rail, capable of measuring vertical force. Vertical impact force was found to decrease with increasing skater experience in stalls (r = −0.84, P = 0.002) and grinds (r = −0.84, P = 0.009). This might imply that less-experienced skaters are (subconsciously) more concerned about maintaining balance than refining technique to minimize impact force. Similar to drop landing experiments, peak impact force decreased with increasing knee flexion during stalls (r = −0.65, P = 0.04). During stalls, skaters demonstrated classic balance maintenance strategies (ankle, hip, or multi-joint) depending on trick length. During grinds, skater centre of mass never passed over the rail base of support, suggesting the use of momentum produced from obliquely approaching the rail.

Machine maintenance with workload considerations

AbstractMachine maintenance is modeled in the setting of a single‐server queue. Machine deterioration corresponds to slower service rates and failure. This leads to higher congestion and an increase in customer holding costs. The decision‐maker decides when to perform maintenance, which may be done pre‐emptively; before catastrophic failures. Similar to classic maintenance control models, the information available to the decision‐maker includes the state of the server. Unlike classic models, the information also includes the number of customers in queue. Considered are both a repair model and a replacement model. In the repair model, with random replacement times, fixed costs are assumed to be constant in the server state. In the replacement model, both constant and variable fixed costs are considered. It is shown in general that the optimal maintenance policies have switching curve structure that is monotone in the server state. However, the switching curve policies for the repair model are not always monotone in the number of customers in the queue. Numerical examples and two heuristics are also presented. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007

Application of RCM for safety considerations in a steel plant

Abstract Any operation or process done on machine or its parts to enhance the efficiency of machine before or after the breakdown is called maintenance. A concern may be said to be successful over the years, when it runs non-interrupted, maintains a smooth production flow consistently and at optimum productivity levels. Plant can achieve productivity up to a satisfactory level by proper maintenance work. The maintenance system may be categorized as either ‘Planned’ or ‘Unplanned‘. The classic maintenance problems in modern industries are insufficient pro-active maintenance, frequent problem repetition, erroneous maintenance work, sound maintenance practices not institutionalized, unnecessary and conservative PM, sketchy rationale for PM actions, lack of traceability/visibility for maintenance program, blind acceptance of OEM inputs, PM variability between like/similar units, paucity of predictive maintenance applications. Hence it was necessary to develop an appropriate methodology to develop strategies and programmatic approach to deal with such problems. The reliability centered maintenance offers the most systematic and efficient process to address an overall programmatic approach to the optimization of plant and equipment maintenance In this paper, the concept of RCM has been applied to process of vacuum degassing/vacuum oxygen decarburising (VD/VOD) in steel melting shop of a medium scale steel industry. Safety consideration is the significant aspect for selection of the system. By systematically applying the RCM methodology, failures, failure modes are analyzed. To preserve the system function, preventive maintenance tasks such as inspection/checking, lubrication, cleaning, adjustment, replacement, are allotted for various failure modes. RCM based preventive maintenance schedule for the system is formulated and compared with the company's existing preventive maintenance schedule. For subsystems such as ejectors, water-ring pumps and the RLC/ladle car/furnace, existing maintenance schedule is conservative. For oxygen lance and cooling pumps, maintenance frequency is to be increased to quarterly from yearly in the present schedule. For condensers bimonthly schedule is recommended as compared to none, whereas for cooling pumps the schedule remains unchanged. This reveals that RCM based tasks need not necessarily increase the frequency but can, retain or even decrease the frequency of maintenance based on functional priorities. RCM can also recommend the additional maintenance tasks. Application of RCM based PM schedule requires use of age exploration technique and attitudinal changes.