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AbstractMedical devices are manmade objects existing at the interface between numerous disciplines. They range from as simple as medical gloves to as complex as artificial limbs. This versatility of medical devices and their inherent interdisciplinary nature means that academic courses on them are attended by cohorts of students from varieties of academic backgrounds, who bring with them similarly broad spectra of interests. To satisfy the learning expectations of each and every student in such diverse classes is a daunting task for the instructor. After many years of teaching medical devices at undergraduate and graduate levels at three different universities in the states of Illinois and California, I have come up with an instructional method that solves this challenge by engaging students in the co-creation of the curriculum via selection of their own medical devices of interest and presentation to the class for collective analysis. The threefold presentations are designed so that they reflect an ascent along the hierarchy of a learning taxonomy extending from foundational concepts to critical assessment of knowledge to creative displays of it. In such a way, the students are acquainted with the ability of critical and creative thinking at the expense of rote memorization or inculcation and are prepared to enter the field of medical devices as innovation-centered individuals. The specifics of this new method of instruction are reported here, with the hope that they will be useful to fellow instructors in any interdisciplinary course that benefits from a balance between the rigorous coverage of the instructional material pertaining to engineering and medicine and the flexible selection of topics that comply with students’ individual interests. [ABSTRACT FROM AUTHOR]

The recipe for making Turkish coffee in some parts of former Yugoslavia calls for the dilution of the turbid liquid with lukewarm water just before the boiling point is reached. The enigmatic gastronomic purpose of this step notwithstanding, here it is being used as an inspiration for deriving a simple stabilization step for protocols for the synthesis of fine particle colloids. The dilution step inspired by coffee-making was performed in a protocol for the synthesis of hydroxyapatite nanoparticles by their precipitation from supersaturated alkaline aqueous solutions. The implementation of this step in the post-precipitation stage, concurrently with boiling, evidently improved the stability of the nanoparticle colloids. The stabilization effect was limited to the suspensions where the parent solution was equilibrated with the fresh precipitate and was not reproduced in colloids comprising HAp nanoparticles redispersed in deionized water. The dilution step produced a mild and counterintuitive increase in crystallinity, suggesting complex recrystallization mechanisms driven by mutually antagonistic dissolution caused by the dilution and reprecipitation caused by the heating to be responsible for the observed increase in stability. Incongruent dissolution favoring a less entropic surface order and reduced charge screening entailing the expansion of the Debye lengths were suggested as complementary mechanisms explaining the improvements in stability caused by adding this simple and economical, yet very efficacious touch to the synthesis. It is concluded that unconventional protocols in spheres other than the scientific and heritages routinely discarded as disreputable could be sources of insight relevant to a plethora of distant domains and disciplines. [ABSTRACT FROM AUTHOR]

The Russian-Ukrainian scientist, G. V. Samsonov left an enormous legacy in materials science, even though a large portion of his and his group's work remained hidden behind the Iron Curtain. One of his crowning theoretical contributions that received but a slight tidbit of resonance in the west was the configurational model of the solid state based on the statistical weight of atoms with stable configuration (SWASC). Only a handful of papers employing this model were published in the western journals since the model was developed, in 1965. Here, the configurational model was tested for its ability to explain the effects of divalent transition elements on solubility of hydroxyapatite when they acted as dopants in it. It is shown that the SWASC values for half-filled d orbitals of transition elements in the ± 5 pm range of ionic radii centered around iron do correlate monotonously with the solubility change induced by the dopant ions relative to the solubility of stoichiometric hydroxyapatite synthesized and analyzed under the same conditions when the solubility values are extrapolated to identical atomic ratios between the dopant ions and the constitutive calcium ions. The effect of SWASC, however, competes with that of the dopant concentration, producing a complex plexus of mutually antagonistic effects. With this work, it is hoped that the interest in the work of G. V. Samsonov and the generation of his Soviet and Yugoslavian scientific contemporaries gets revived and their legacy in the west popularized. [ABSTRACT FROM AUTHOR]

The synthetic analogue to biogenic apatite, hydroxyapatite (HA) has a number of physicochemical properties that make it an attractive candidate for diagnosis, treatment of disease and augmentation of biological tissues. Here we describe some of the recent studies on HA, which may provide bases for a number of new medical applications. The content of this review is divided to different medical application modes utilizing HA, including tissue engineering, medical implants, controlled drug delivery, gene therapies, cancer therapies and bioimaging. A number of advantages of HA over other biomaterials emerge from this discourse, including (i) biocompatibility, (ii) bioactivity, (iii) relatively simple synthesis protocols for the fabrication of nanoparticles with specific sizes and shapes, (iv) smart response to environmental stimuli, (v) facile functionalization and surface modification through noncovalent interactions, and (vi) the capacity for being simultaneously loaded with a wide range of therapeutic agents and switched to bioimaging modalities for uses in theranostics. A special section is dedicated to analysis of the safety of particulate HA as a component of parenterally administrable medications. It is concluded that despite the fact that many benefits come with the usage of HA, its deficiencies and potential side effects must be addressed before the translation to the clinical domain is pursued. Although HA has been known in the biomaterials world as the exemplar of safety, this safety proves to be the function of size, morphology, surface ligands and other structural and compositional parameters defining the particles. For this reason, each HA, especially when it comes in a novel structural form, must be treated anew from the safety research angle before being allowed to enter the clinical stage. [ABSTRACT FROM AUTHOR]

Microelectrophoresis based on the dynamic light scattering (DLS) effect has been a major tool for assessing and controlling the conditions for stability of colloidal systems. However, both the DLS methods for characterization of the hydrodynamic size of dispersed submicron particles and the theory behind the electrokinetic phenomena are associated with fundamental and practical approximations that limit their sensitivity and information output. Some of these fundamental limitations, including the spherical approximation of DLS measurements and an inability of microelectrophoretic analyses of colloidal systems to detect discrete charges and differ between differently charged particle surfaces due to rotational diffusion and particle orientation averaging, are revisited in this work. Along with that, the main prospects of these two analytical methods are mentioned. A detailed review of the role of zeta potential in processes of biochemical nature is given too. It is argued that although zeta potential has been used as one of the main parameters in controlling the stability of colloidal dispersions, its application potentials are much broader. Manipulating surface charges of interacting species in designing complex soft matter morphologies using the concept of zeta potential, intensively investigated recently, is given as one of the examples. Branching out from the field of colloid chemistry, DLS and zeta potential analyses are now increasingly finding application in drug delivery, biotechnologies, physical chemistry of nanoscale phenomena and other research fields that stand on the frontier of the contemporary science. Coupling the DLS-based microelectrophoretic systems with complementary characterization methods is mentioned as one of the prosperous paths for increasing the information output of these two analytical techniques. [ABSTRACT FROM AUTHOR]

Presented is a discourse on the contextual nature of physical qualities. The realistic and observational contexts in which a system exists are demonstrated as equally involved in defining its qualities. Each quality could be consequently considered as natural and experiential at the same time. The subsequently proposed thesis of the contextual co-definition of natural/experiential qualities in the relationship between the human mind and Nature is shown to possess numerous favorable ethical and aesthetical implications. The contextual nature of experiential qualities is further correlated with the holistic character of natural systems and events, which is illustrated by several real-life examples. A systemic approach to knowledge is shown to naturally emanate from the acceptance of the contextual definition of physical qualities and the holistic nature of experiences. Methodological problems of the standard, reductionist explanatory frameworks are additionally discussed with an emphasis on the major descriptive flaws of quantificational approaches and in respect to cybernetic and autopoietic organization of physical and biological systems. [ABSTRACT FROM AUTHOR]

Scientific method is presented not as a means for investigating a true and objective character of universal reality, but as a metaphorical tool applied for mutual co-ordination of experiences. By acknowledging the co-orientational and metaphoric roots of science, religion, arts, and ordinary linguistic communications alike, potential for their fruitful interdependent application becomes apparent. References to the paradigms of constructivism and objectivism are drawn in parallel in outlining the tracks along which the proposed concept of co-creation of experiential qualities is arrived at. Systemic reasoning based on analogies between different levels of complexity of natural systems emanates as an imaginative aspect of creative thinking. [ABSTRACT FROM AUTHOR]

The reported is a method for the preparation of stable dispersions of narrowly dispersed cholesterol crystals, which may provide an excellent model for the aggregation studies thereof. The effects of experimental parameters that include concentration, pH, ionic strength, temperature, and aging on the resulting morphologies are acknowledged. Regardless of the cause of destabilization, the multilayered aggregates of cholesterol particles are formed by “face-to-face” stacking of the original platelets, as promoted by higher surface charge density on particle sides comparing to their faces. In accordance with the crucial involvement of surface charge effects in stabilization of cholesterol dispersions produced hereby, aggregation of the original particles becomes enhanced at increased salt contents and at pH conditions that correspond to the isoelectric point of the dispersed particles. [ABSTRACT FROM AUTHOR]

Crystallization of cholesterol in chemical conditions that involve the presence of emulsions of three different types of surface active agents - cationic, anionic, and nonionic - was investigated by means of scanning and transmission electron microscopic analyses. In contrast with the previous attempts to modify the typical plate- and needle-shaped character of biaxially grown cholesterol crystals, the present study indicates that spherical templates of fine emulsion droplets may impose spherical morphologies to cholesterol particles nucleated within. [ABSTRACT FROM AUTHOR]