Kratica J.,Serbian Academy of Science and Arts
Computers and Industrial Engineering | Year: 2013
This paper deals with the uncapacitated multiple allocation p-hub median problem (UMApHMP). An electromagnetism-like (EM) method is proposed for solving this NP-hard problem. Our new scaling technique, combined with the movement based on the attraction-repulsion mechanism, directs the EM towards promising search regions. Numerical results on a battery of benchmark instances known from the literature are reported. They show that the EM reaches all previously known optimal solutions, and gives excellent results on large-scale instances. The present approach is also extended to solve the capacitated version of the problem. As it was the case in the uncapacitated version, EM also reached all previously known optimal solutions. © 2013 Elsevier Ltd. All rights reserved.
Uskokovic V.,University of California at San Francisco |
Uskokovic D.P.,Serbian Academy of Science and Arts
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2011
The first part of this review looks at the fundamental properties of hydroxyapatite (HAP), the basic mineral constituent of mammalian hard tissues, including the physicochemical features that govern its formation by precipitation. A special emphasis is placed on the analysis of qualities of different methods of synthesis and of the phase transformations intrinsic to the formation of HAP following precipitation from aqueous solutions. This serves as an introduction to the second part and the main subject of this review, which relates to the discourse regarding the prospects of fabrication of ultrafine, nanosized particles based on calcium phosphate carriers with various therapeutic and/or diagnostic agents coated on and/or encapsulated within the particles. It is said that the particles could be either surface-functionalized with amphiphiles, peptides, proteins, or nucleic acids or injected with therapeutic agents, magnetic ions, or fluorescent molecules. Depending on the additive, they could be subsequently used for a variety of applications, including the controlled delivery and release of therapeutic agents (extracellularly or intracellularly), magnetic resonance imaging and hyperthermia therapy, cell separation, blood detoxification, peptide or oligonucleotide chromatography and ultrasensitive detection of biomolecules, and in vivo and in vitro gene transfection. Calcium phosphate nanoparticles as carriers of therapeutic agents that would enable a controlled drug release to treat a given bone infection and at the same be resorbed in the body so as to regenerate hard tissue lost to disease are emphasized hereby as one of the potentially attractive smart materials for the modern medicine. © 2010 Wiley Periodicals, Inc.
Herbut F.,Serbian Academy of Science and Arts
International Journal of Quantum Information | Year: 2014
Measurement of a degenerate (or non-degenerate) discrete observable is investigated in the framework of quantum measurement theory short of collapse, i.e. premeasurement theory, based on a unitary evolution operator that includes the measurement interaction between object and measuring instrument. A pointer observable with eigen-projectors of, in general, many (or even infinitely) dimensional ranges is introduced as a new approach. It leads to redundant entanglement in the final state. As the first main result, the basic dynamical relation of the approach is derived. It is shown to be equivalent to the calibration condition, which is known to define general exact measurement. The latter is given a practical form. Complete measurement (premeasurement with objectification or collapse), which is in some sense implied by the premeasurement theory, performed on a subsystem of a bipartite object in a pure state is studied with particular attention to its effect on the opposite, interactionally unaffected subsystem. The change of state of the latter is derived for exact complete subsystem measurement, and it is shown that the change is the same as for the simplest, i.e. ideal measurement (this is the second main result). It is applied to the case of twin observables and thus distant measurement obtains a new, more satisfactory, foundation (the third main result). Distant measurement is a basic concept in the EPR phenomenon. The well-known importance of the latter implies importance of the former. © 2014 World Scientific Publishing Company.
Stevanovic M.,Serbian Academy of Science and Arts
International journal of nanomedicine | Year: 2011
Highly stable dispersions of nanosized silver particles were synthesized using a straightforward, cost-effective, and ecofriendly method. Nontoxic glucose was utilized as a reducing agent and poly-α, γ, L-glutamic acid (PGA), a naturally occurring anionic polymer, was used as a capping agent to protect the silver nanoparticles from agglomeration and render them biocompatible. Use of ammonia during synthesis was avoided. Our study clearly demonstrates how the concentration of the capping agent plays a major role in determining the dimensions, morphology, and stability, as well as toxicity of a silver colloidal solution. Hence, proper optimization is necessary to develop silver colloids of narrow size distribution. The samples were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurement. MTT assay results indicated good biocompatibility of the PGA-capped silver nanoparticles. Formation of intracellular reactive oxygen species was measured spectrophotometrically using 2,7-dichlorofluorescein diacetate as a fluorescent probe, and it was shown that the PGA-capped silver nanoparticles did not induce intracellular formation of reactive oxygen species.
Kadijevich D.M.,Serbian Academy of Science and Arts
Journal of Educational Computing Research | Year: 2012
By using a sample of 1st-year undergraduate business students, this study dealt with the development of simple (deterministic and non-optimization) spreadsheet models of income statements within an introductory course on business informatics. The study examined students' errors in doing this for business situations of their choice and found three kinds of errors: errors in selecting variables, errors in initializing variables, and errors in relating variables. This article describes these errors, discusses possible reasons for them from different research perspectives, and gives suggestions for further practice and research. These perspectives dealt with modeling with spreadsheets, spreadsheets as mindtools, and errors in operational spreadsheets. The article is primarily directed to teachers of modeling with spreadsheets, interested in taking a broader view of the subject. © 2012, Baywood Publishing Co., Inc.