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The selection of the suitable production parameters for dry machining remains a challenging task which impacts the productivity, the system degradation and the quality of the output product. This study proposes an integrated production-maintenance policy allowing the simultaneous consideration of the production parameters, mainly the cutting speed, the production time and cost, the preventive maintenance period and the quality levels and the selling prices of the output product. A special feature of this strategy, defined on a finite time span, is to allow a change of the cutting speed at a certain instant to be determined in an optimal way concurrently with the preventive maintenance period, such as to maximise the total expected profit per time unit. A mathematical model is developed to express the average profit per time unit as a function of the decision variables. A solving procedure is also proposed. A numerical example and a sensitivity analysis are presented in order to show the impact of some major input parameters on the optimal policy. [ABSTRACT FROM AUTHOR]

Nowadays companies have to consider the impact of their production systems on the environment. This paper presents a condition-based maintenance policy for a production system under environmental constraints. The studied system is subject to random failures that can cause production losses and have a negative influence on the environment. Such failures cause the release of a refrigerant gas that induces a heavy penalty cost from a given threshold level. A mathematical model is developed in order to reduce environmental degradation where the average cycle cost per time unit is considered as the objective function. A numerical example and a sensitivity study are given to illustrate the proposed model. [ABSTRACT FROM PUBLISHER]

This article, inspired by an industrial problem, develops efficient maintenance and just-in-time production policies in a subcontracting environment according to two orientations. The first invokes subcontracting with the objective of satisfying a constant customer demand knowing that our production system, composed of a machine M1, cannot satisfy the totality of demand. Subcontracting is represented by a machine M2 which has a constant failure rate, while three maintenance policies for M1 are tested and evaluated. The second orientation takes the perspective of our production system as a supplier which is obliged to allocate part of its production capacity to subcontracting so as to satisfy a constant demand. We consider a production system made up of two machines, both of which produce a single type of product, are subject to breakdowns and can carry out subcontracting tasks. The objective of this part of the article is to prove the efficiency of the so-called integrated maintenance policy, which combines production and maintenance decisions in a subcontracting environment. [ABSTRACT FROM AUTHOR]

This paper investigates an integrated strategy of inventory control and preventive maintenance for a randomly failing production unit subject to a minimum required availability level. The production unit is submitted to a maintenance action as soon as it reaches a certain age m or at failure, whichever occurs first. A buffer stock h is built up at time A from the start of a production cycle in order to allow a continuous supply of the subsequent production unit at a constant rate during repair and preventive maintenance actions whose respective durations are random. A mathematical model and a numerical procedure are developed to find simultaneously the optimal values of the three decision variables (m*, h*, A*) which minimize the total average cost per time unit and satisfy the availability constraint. [ABSTRACT FROM AUTHOR]

The paper describes a new preventive maintenance approach for manufacturing systems under environment constraints. The manufacturing system under consideration consists of a machine M1 that produces a single product in a Just-in-Time context. To satisfy a constant demand d, the system called upon another machine M2 (the subcontractor), comprising the so-called environment, which produces at a certain rate the same type of product as M1. Both machines are subjected to random failures. Whereas machine M2 is uncontrollable from the maintenance point of view, an age-limit policy is used for preventive maintenance of machine M1. It is proved that the best age to perform preventive maintenance depends on the history of machine M1 and the state of M2. A numerical example is used to illustrate the proposed approach. [ABSTRACT FROM AUTHOR]

The protein dystrophin has been identified as the muscle component that is affected in many cases of muscular dystrophy. In Duchenne muscular dystrophy, dystrophin seems to be absent, while in other forms, such as Becker muscular dystrophy, the protein is present, but altered. Both Duchenne and Becker muscular dystrophy directly involve the dystrophin gene, which is on the X chromosome, accounting for the sex-linkage of these forms of the disease. However, other forms of muscular dystrophy exist in which both sexes are affected with equal frequency, rather than the preponderance of affected boys observed with X-linked diseases. This is the case with severe childhood autosomal recessive muscular dystrophy (SCARMD), which has many clinical and laboratory features in common with Duchenne and Becker muscular dystrophy. For this reason, it is important to determine if dystrophin is normally expressed in the muscle cells of patients with SCARMD. Muscle biopsies were taken from 10 patients with Duchenne muscular dystrophy, 20 patients with SCARMD, and 10 control subjects. Immunohistochemical techniques using anti-dystrophin antiserum detected dystrophin in the muscle tissue of the patients with SCARMD. This observation was confirmed using the immunoblot technique, which explicitly reveals the molecular weight of the material reacting with the antibody, and thus is resistant to misinterpretation resulting from spurious cross-reactions of the antiserum used in the tests. The results demonstrate that although the clinical features of SCARMD are similar to those of the X-linked muscular dystrophies, these pathological symptoms do not result from an alteration in the expression of the protein dystrophin. (Consumer Summary produced by Reliance Medical Information, Inc.)

Maintenance activities represent a significant pillar in industry. Its real goal consists at improving the production systems productivity. Specially, TPM represents one of the main evolutions of the maintenance methods in order to improve the machines efficiency by a proactive approach. This paper presents an overview of several TPM implantations and especially efficiency and effectiveness measurement of the TPM in several industries. In a second hand, a proposition of possible extension about analytical assessment of the TPM performance, based on both technical and economic criteria, is presented.

This paper models and predicts how the strengthening of intellectual property (IP) protection will impact R&D in developing economies. International agreements such as TRIPs and free trade agreements are enhancing the level of international control on IP. This is changing deeply the R&D environment in developing economies by restraining illegal channels of knowledge accumulation such as imitation, reverse engineering and piracy. An asymmetric and non-cooperative two-stage (R&D-Production) game is proposed to model a developing market where two local firms compete with a more innovative foreign firm. Equilibrium R&D expenditures and profits of the competing firms are compared for different levels of: market technology, technological gaps and IP protection. The proposed model shows clearly that a stringent enforcement of IP agreements will dramatically decrease the innovative abilities of developing economies especially in high technological sectors. The maintain and increase of their R&D skills will not be possible without a reduction of their technological gap and strong incentives to initiate regulatory (or permit tacit) R&D cooperation between local firms., (© The Indian Econometric Society 2021.)

The serum of a 4-year-old child with severe hypertrophic peripheral neuropathy contained high-titer polyclonal antibodies, mainly of IgG class, reacting with the 30-kd P0 glycoprotein of peripheral nerve. This was demonstrated by indirect immunofluorescence, immunoblot analysis of myelin proteins, and enzyme-linked immunosorbent assay with purified P0 glycoprotein. The antibodies did not react with myelin-associated glycoprotein, sulfated glycuronic acid-containing paragloboside (SGPG and SGLPG), or other peripheral nerve glycolipids or gangliosides. To our knowledge this is the first report of strong antibody activity specifically directed against P0. This antibody may play a causative role in the pathogenesis of the peripheral neuropathy in this patient.

An immunological mechanism may be responsible for the peripheral neuropathies related to IgM monoclonal gammopathies. Myelin-associated glycoprotein (MAG) has been found to be one the main target antigens for these paraproteinemias. Glycosphingolipids of peripheral nerve have been also found to be targets for these antibodies, especially a sulfated glycosphingolipid containing glucuronic acid (GLSG) specific for peripheral nerve. Crossed reactivity has been found between MAG and GLSG. Anti-glycolipid antibodies were determined in 14 patients with IgM gammopathy and polyneuropathy. Glycosphingolipids from human peripheral nerve were purified and chromatographed by thin-layer chromatography for immunodetection of the antibodies. The 12 patients who had GLSG antibody activity had a clinical status identical to the reported cases of dysglobulinemic neuropathies with anti-MAG antibodies.