Functionalisation of silicone by drug-embedded chitosan nanoparticles for potential applications in otorhinolaryngologyUrban Ajdnik
, Lidija Fras Zemljič
, Matej Bračič
, Uroš Maver
, Olivija Plohl
, Janez Rebol
, 2019, original scientific article
Keywords: silicone, tympanostomy tube, chitosan, nanoparticles, drug delivery, antimicrobial activity
Published: 22.03.2019; Views: 510; Downloads: 6
Holistic thinking aproachAndrej Lisec
, Bojan Rosi
, Zvonko Kavran
, 2008, original scientific article
Abstract: Modern complexity of management is associated with im- portant decision making, confronting a great number of useless information. Selection of information - the choice of only qual-ity ones, i. e. essential ones, is a big problem in management decision-making. Implementation of systemic approach i. e. dialectical-network thinking (DNT) can help to deal with it. The paper presents a holistic thinking approach in a case study for the Slovenian parcel postal problem. The volume of parcel flows at the Post of Slovenia between Posts is increasing rapidly and it requires a new design of the postal network. This paper presents a reorganization of parcel services between Postal Logistics Centers and Posts by adding Regional Parcel Centers and Parcel Posts to the network. A case for the area covered by Ljubljana Postal Logistics Center is given, which takes into consideration the sorting out and the retaining of parcels in the Posts, Parcel Posts and Regional Parcel Centers within their individual areas.
Keywords: systemic thinking, dialectical network thinking, management, logistics, postal services, postal delivery
Published: 02.06.2017; Views: 1146; Downloads: 78
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Reconstruction of delivery positions in the city of Celje, SloveniaDejan Dragan
, Klemen Prah
, Tea Vizinger
, Marko Intihar
, Maja Fošner
, Tomaž Kramberger
, 2013, original scientific article
Abstract: The paper addresses the problem of the reconstruction and allocation of delivery positions in the urban area. The aim is to achieve the optimal reorganization of urban freight transport in old town core in the municipality of Celje. Optimal allocation relies on optimization based on the Monte Carlo simulation and represents a first stage of a two-stage optimization approach to re-design the existing urban freight transport. The number of optimal delivery positions is required to be as minimal as possible, which can still assure a maximal service area within the prescribed radius, while keeping the minimal walking distances of delivery personnel between the nearest delivery position and the customerʼs physical location. The main issues of the used heuristic allocation algorithm and the presentation of calculated results are provided. In the near future, the calculated delivery positions are going to be used for the purpose of physical implementation in order to improve the existing delivery transport.
Keywords: urban transport problems, urban freight transport, delivery, optimization, maximum location covering problems, MLCP, Monte-Carlo simulation
Published: 10.07.2015; Views: 849; Downloads: 95
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Antimicrobial medical textiles based on chitosan nanoparticles for gynaecological treatmentTijana Ristić
, 2014, doctoral dissertation
Abstract: The aim of this dissertation was to develop a novel medical tampon for alternative gynaecological treatment using chitosan nanoparticles as an antimicrobial agent or as a drug delivery system. For this purpose viscose tampon band was used and functionalized with chitosan and trimethyl chitosan nanoparticles. A comprehensive of interactions between chitosan and cellulose as well as characterization of prepared materials were done. At the beginning, chitosan (CS) and trimethyl chitosan (TMC) solutions, as well as nanoparticles synthesised by ionic gelation were studied. Their characterization was focused on determining the charge and antimicrobial properties against common pathogenic microorganism. The influence of cationic charge on the inhibition of microbial growth was confirmed. Since CS and TMC solutions and nanoparticles dispersions exhibited antibacterial activity against Lactobacillus, a detailed investigation in chitosan’s antimicrobial mode of action was performed using a novel diffusion nuclear magnetic resonance (D-NMR). D-NMR allowed the monitoring of intra- and extracellular water exchange from the cells indicating the membrane alteration and leakage of intracellular constituencies. Further, in order to study the adsorption phenomena and molecular interactions between CS/TMC (solution or nanoparticles) and cellulose material, model cellulose surfaces were used, and adsorption was studied by quartz crystal microbalance with dissipation. CS and TMC were favourably deposited onto cellulose model surface at higher ionic strength, higher pH values, i.e. factors causing lower solubility, where the presence of electrostatic interactions was negligible and non-electrostatic interactions were dominant. The knowledge gained from the model surfaces was extremely helpful in characterization of real systems, i.e. functionalized cellulose fibres and for understanding the obtained results. Immobilization of CS and TMC (in the form of solution and/or nanoparticles) onto cellulose viscose fibres was confirmed with several analytical methods. The attachment of chitosan onto fibres was reversible, as endorsed with desorption studies mimicking the conditions of vaginal usage. Evaluation of antimicrobial properties was performed using two different techniques, both revealing a high inhibition of the tested microorganism. In addition, Lactobacillus susceptibility testing has shown that chitosan-coated fibres do not have any negative influence on the resident microbiota. Assessment of in-vitro cytotoxicity demonstrated that samples do not cause a cytotoxic effect in direct contact. Additionally, model drug was incorporated into chitosan nanoparticles and subsequently attached onto fibres in order to create modern, vaginal drug delivery systems. Antimicrobial medical textiles investigated in the scope of this dissertation show the potential for their exploitation in gynaecological field as preventive or curative treatment without triggering any adverse effects for the user.
Keywords: chitosan, N, N, N-trimethyl chitosan, nanoparticles, antimicrobial activity, cellulose model films, regenerated cellulose fibres, diffusion nuclear magnetic resonance, quartz crystal microbalance, vaginal infections, drug delivery systems, cytotoxicity
Published: 13.02.2014; Views: 2560; Downloads: 111
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Optimization of delivery of postal items with the use of new postcodesBojan Radinja
, Andrej Lisec
, 2009, original scientific article
Abstract: Slovenia currently uses four-digit postcodes. However, they are not completely exploited. In this article a new structure of postcodes is given in order to sort postal mail and parcels for different delivery points. Postcodes will give complete information on the final destination of postal items. The present use of postcodes is being upgraded by adding postcodes of delivery points to the existing postcodes of post offices. By analyzing the use of postcodes in various countries, our findings have been confirmed. It is indeed reasonable to introduce new postcodes, which would together with a proper reading technology increase the efficiency and the speed of direction.
Keywords: post, delivery, postcode, adress
Published: 05.06.2012; Views: 1665; Downloads: 34
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