1- Introduction

2- Literature review

3- Problem formulation

4- Solving method

5- Model implementation and numerical results

6- Conclusion

References

Abstract

Medical Supply chain network design is one of the crucial planning problems that if solved efficiently and effectively, can alleviate the dangers arising from the accumulation of wastes. Furthermore, the harmful effects of medical waste, with their infectious nature in the environment, have increased justifies the significance of this research. In this article, forward and reverse supply chain network design for consumer medical products is considered taking into account the biological risks. The proposed model has two objectives: first, maximizing the profit obtained from subtracting the costs from the revenues of the supply chain. Revenues are gained from selling medical supplies to hospitals and medical wastes to recycling centers, as well as getting the permission to use sterilize services from clinics lacking a sterilization center. The costs include activation cost of inventory, sterilization and collection centers, transportation cost, purchasing cost of medical supplies, municipality cost for destruction of medical waste, etc. The second objective is to reduce biological risks. The primary source of infectious medical supplies is from disposable supplies and equipment. Thus, the second objective function is to minimize the distance and travel time between the clinic and the sterilization center. The proposed model is implemented in hospitals in Tehran’s 4th municipal district using the Bounded De Novo Programming approach which initially attempts to redesign rare sources of the problem. The issue has two types of resource and policy constraints. The policy constraints of the problem cannot be changed, which is why the bounded De Novo Programming approach is used to solve the problem. Redesigning the capacity of the sterilization center leads to the decrease of biological risks, and in addition to can causes to increasing profitability. Also, by raising the productivity of medical waste in the recycling process, the distribution center can receive more profits.

Introduction

In the past, producers and consumers were not responsible for the products used. In other words, they were careless of the post consumption process. Many of the consumed and expired products were out of place, regardless of the extent of their return. They saw a fate of including burial, burning, or destruction ahead of them. Each of the above operations would undoubtedly impose destructive effects and damage to the surrounding environment. Now, the point of view of the advancement and development of countries, people, and the government are expecting to pay attention to their funds (Guo et al. 2019). Therefore, the producers plan to reduce the production of their defective goods. Thus, organizations are working to prevent more of the waste by devising an effective and efficient system in distribution network management. In turn, it includes determining the role of existing or potential supply chain resources as well as the interactions between these entities to manage the physical flows related to the recycling of products (Rajendran and Ravindran, 2019).

Abstract

1- Introduction

1-1- Ag as antimicrobial particles

1-2- Surface Ag-NPs characteristics

1-3- Ag-NPs leading to bacterial inactivation in the dark

1-4- Ag-NPs surfaces leading to bacterial inactivation

1-5- Microstructure of nanoparticles on surfaces sputtered by DCMS, DCPMS and HIPIMS: Critical issues

1-6- Nitride selection when using antimicrobial metal nitrides under light irradiation: TEM-microstructure of Ag-nitride films

1-7- Evidence for the interfacial charge transfer (IFCT) mechanism in semiconductors under light leading to bacterial inactivation

1-8- Dependence of the Ag-nitride mediated bacterial inactivation kinetics on the applied light dose

1-9- Effect of the sputtering energies on the film microstructure and the bacterial inactivation kinetics

2- Introduction

2-1- Cu as antimicrobial particles (Cu-NPs) and Cu-films: Critical issues

2-2- Cu-surfaces and catheter devices obtained by sol-gel methods

2-3- Sputtered films leading to bacterial inactivation in the dark and under light

2-4- Cu bacterial inactivation under light and in the dark: Scientific bases

2-5- Features of antimicrobial Cu-decorated surfaces under light and in the dark

2-6- Effects of the Cu/TiO2 films microstructure on bacterial inactivation kinetics

2-7- Protection of the Cu-ion release in sputtered films increases the sample stability

2-8- Inactivation of Gram-positive methicillin resistant staphylococcus aureus (MRSA) and other pathogens on Cu-surfaces

2-9- Cu-sputtered surfaces: Implications of the applied deposition energy

3- Introduction

3-1- Ag-Cu as antibacterial bimetal materials

3-2- Colloidal loaded Ag-Cu NPs and films leading to bacterial inactivation

3-3- Ag-Cu films leading to bacterial inactivation with a quasi-instantaneous kinetics

3-4- Mechanism suggested for the bacterial inactivation of Ag-Cu films

3-5- Surface potential and pH-changes during bacterial inactivation

3-6- TEM imaging and XPS analysis of Ag-Cu films

3-7- E. coli and MRSA inactivation on Ag-Cu films: corrosion of the film during the bacteria/fungi inactivation

3-8- Effect of the Ag, Cu and Ag-Cu films on normal and porinless E. coli. Differentiation of ionic and surface-contact effects

3-9- Infrared spectroscopy of the functional groups abatement leading to bacterial lysis

3-10- Mechanism of the interfacial charge transfer (IFCT) during bacterial inactivation

3-11- Conclusions

3-12- Outlook

References

Abstract

The design, synthesis, fundamentals and evaluation of 2D/3D antimicrobial surfaces are addressed in detail in the current review. Recent advances in the antimicrobial mechanism, kinetics and properties of Ag, Cu and AgCu surfaces in the dark and under light irradiation are described and discussed. The structure-reactivity relations in the catalyst/photocatalyst layers were described by way of the surface characterization and the observed antibacterial kinetics. Escherichia coli (E. coli) and Methicillin resistant Staphylococcus aureus MRSA bacteria are selected as model pathogens to evaluate the antimicrobial inactivation kinetics. The separate antimicrobial properties of ions and the antimicrobial surface-contact effects are presented in a detailed way. The interfacial charge transfer (IFCT) mechanism and the identification of the most relevant reactive oxygen species (ROS) leading to bacterial disinfection are considered. The recently developed monitoring of the changes of the film surface potential (Eigenvalues) during bacterial inactivation and the redox reactions associated with catalyst/ photocatalyst surfaces are also presented. The potential for practical applications of these innovative 2D films and 3D sputtered medical devices in health-care facilities are accounted for in the present review.

Introduction

Since decades, nano-silver has been used as an antibacterial material. Ag-nanoparticles cannot be compared to conventional chemicals or bulk materials when trying to elucidate its bactericide action. Products containing nano-silver particles have been commercially available for over 100 years and have been used in different applications [1]. The medical uses of Ag-suspensions, Ag-healing pads and Ag-ions have been reported for the last few decades. Lately, there has been a renewed interest in silver coatings for antimicrobial purposes due to the increased resistance of bacteria to antibiotics [2]. The bacterial inactivation by Ag proceeds by the release of silver-ions penetrating the bacteria cytoplasm through the bacterial porins and by the silver nanoparticles in contact with the bacterial outer-wall [2]. Also, silver nanoparticles (Ag-NPs) have been reported to inactivate bacteria and other pathogens through the oligodynamic effect involving the diffusion of 10−6 -10-9 mol/l (ppm-ppb) amounts in contact with the bacterial outer cell envelope [2–6]. Ag-NPs disinfection proceeds in suspension or deposited on films through the destruction of cell wall by reactive oxygen species (ROS) [1–9]. The Ag-toxicity towards bacteria, viruses and fungi is significantly higher compared to the toxicity reported for mammalian cells [4,5]. Silver ions have an affinity towards sulfhydryl groups located at the cell wall, interfering with the electron transport chain through the cell wall porins diffusing to the interior of the bacteria. Ag-ions have also been reported to block the respiratory chain of microorganisms without inducing resistance to silver ions with a few exceptions [7]. The concentrations required for bactericidal activity are in the ppb range (10−9 mol/l). Metallic silver particles react with moisture, releasing highly oxidative Ag-ions. These Ag-ions complex with DNA and RNA, which inhibit the microorganism replication [8]. Recent reviews report that the size, shape and concentration of Ag-NPs control their antimicrobial kinetics and efficiency [9]. Treatment of thermal burns by Ag-NPs to preclude infections during the healing process has been known for over The ability of Ag-NPs and Cu-NPs associated ions to destroy biofilms is based on their ability to penetrate the biofilm due to their small size. The hindrance to the biofilm formation due to the fast bacterial inactivation kinetics of metal Ag-NPs is an important focus of current research. In contrast to traditional antibiotics, M-NPs have small dimensions < 100 nm and present a larger surface area-to-mass ratio [1]. Toxic biofilms spread highly toxic pathogens in healthcare facilities and public places. Biofilms provide protection to bacterial strains by embedding them in a polymeric network structure. This hinders the penetration of most antibiotics. Bacteria biofilms produce extracellular polymeric substances (ESP) when sticking to surfaces that subsequently protect the biofilm. This allows the film matrix to remain stable for a long-time [11]. The hydrophilic–hydrophobic balance between the surface of polymer films and the bacteria envelope has a great influence on the release of Ag-NPs-ions deposited on a polymer network [12].