433 research outputs found
Membru de onoare Ion Petrescu biobibliografie
No full textThis volume includes an autobiographical essay by management expert and teacher Ion Petrescu, two articles by him about aspects of management,a series of short testimonies to him by friends and colleagues, and a bibliography of his work
From structural colors to super-hydrophobicity and achromatic transparent protective coatings: Ion plating plasma assisted TiO2 and SiO2 nano-film deposition
No full textThe implementation of the Ion Plating Plasma Assisted technology in the area of surface functionalization for structural color and relic preservation applications is presented. Interferometric structural colors on irregular bumped Titanium surfaces and transparent and achromatic nano films on ancient ceramic artifact have been investigated. Titanium metal and ceramic supports have been utilized for the surface functionalization tests: A metallic electron beam additive manufactured Titanium component and an ancient tile of the XIX century, which was characterized by strong chromatic valence and by a mixed porous and glazed surfaces, have been considered. A reactive magnetron sputtering Ion Plating Plasma Assisted apparatus operating in Argon or Oxygen atmospheres for TiO2 and SiO2 deposition has been utilized. Preliminary tests with two plasma treatments were carried out for optimal processing conditions definition. TiO2 nano-film deposition on irregular Ti surfaces has generated light direction depending color-changing surfaces while good achromatic and transparent coatings were obtained by using SiO2 coating. The high processing flexibility of the Ion plating technology is discussed. The SiO2 IPPA surfaces treatment resulted more convenient for restorative and preservation ancient historical tile was used to finally test the optimized process with Ion Beam Electron Microscopy, which was carried out on the tile porous structure, confirmed the high flexibility and efficiency of the innovative IPPA technology
Nanodiamond for Structural Biomimetic Scaffolds
No full textBio-mechanically active scaffolds for tissue engineering combining hydrophilic polymeric matrix and nano-diamond fillers properties are presented and discussed in this paper. The resulting scaffolding materials revealed remarkable mechanical and biological properties to be exploited in advanced biomedical applications. The novel hybrid material is based on 2 and 5 volume % of detonation nano-diamond particles in a hydrophilic poly-(hydroxyl-ethyl-methacrylate) matrix. According to its mechanical and biological properties, the nanocomposite shows a hybrid nature. The base analytical procedures for the preparation of the hybrid nanocomposites and some preliminary mechanical characteristics are presented. The proposed hybrid system has been considered for potential biomimetic, osteoconductive and osteoinductive scaffolds application in bio-mechanically active bone scaffolds for osteoblast and stem cell differentiation and growth. These more rigid hybrid nano-composites are predicted to possess improved mechanical strength overcoming the mechanical weaknesses of traditional hydrogels clinically utilized for bone regeneration
The basic elements of life’s
No full textThe four basic elements of life are: Oxygen, hydrogen, nitrogen and phosphorus. These four elements are found in abundance in both the human body and in animals. There are other elements that compose the human body, but the four we've highlighted participate in all life processes. Besides, these four elements make up ATP chains (molecule), which governs and controls the body entirely energy processes and physiological and pathological processes of the human body. Oxygen is the pivot, which produces water and air and it is indispensable to the life. Hydrogen participates with oxygen to produce water, without which life would not be possible. Nitrogen with oxygen constitutes basic elements of air that compose the Earth's atmosphere. Phosphorus is the last element of human energy chain. It is the fire and light. In other words, human energy chain consists of four basic elements, or three compounds: Water, air and fire (light). In genetics, all cellular energy processes are driven and controlled by ATP molecule type. If we consider the chain of human genes, account must also be taken of the element carbon. In this mode, the four elements of life become the five elements of life: Oxygen, hydrogen, nitrogen, phosphorus and carbon
Some proposed solutions to achieve nuclear fusion
No full textDespite research carried out around the world since the 1950s, no industrial application of fusion to energy production has yet succeeded, apart from nuclear weapons with the H-bomb, since this application does not aims at containing and controlling the reaction produced. There are, however, some other less mediated uses, such as neutron generators. The fusion of light nuclei releases enormous amounts of energy from the attraction between the nucleons due to the strong interaction (nuclear binding energy). Fusion it is with nuclear fission one of the two main types of nuclear reactions applied. The mass of the new atom obtained by the fusion is less than the sum of the masses of the two light atoms. In the process of fusion, part of the mass is transformed into energy in its simplest form: heat. This loss is explained by the Einstein known formula E=mc2. Unlike nuclear fission, the fusion products themselves (mainly helium 4) are not radioactive, but when the reaction is used to emit fast neutrons, they can transform the nuclei that capture them into isotopes that some of them can be radioactive. In order to be able to start and to be maintained with the success the nuclear fusion reactions, it is first necessary to know all this reactions very well. This means that it is necessary to know both the main reactions that may take place in a nuclear reactor and their sense and effects. The main aim is to choose and coupling the most convenient reactions, forcing by technical means for their production in the reactor. Taking into account that there are a multitude of possible variants, it is necessary to consider in advance the solutions that we consider them optimal. The paper takes into account both variants of nuclear fusion, and cold and hot. For each variant will be mentioned the minimum necessary specifications
Biologically structured materials
No full textIn this paper bio-tissue mathematical modeling serves as a central repository to interface design, simulation, and tissue fabrication. Finite element computer analyses will be used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and mandible thickness distributions using single and multi-phase continuum material representations of clinical cases of patients implanted with the traditional protocols. New protocols will be hypothesized for the use of the new biologically techno-structured hybrid materials
Physiologic human fluids and swelling behavior of hydrophilic biocompatible hybrid ceramo-polymeric materials
No full textAll synthetic and natural materials to be used in biomedical applications that involve the contact with human body need to be investigated for their physical and chemical modification induced by the human physiological fluids contact and sorption. The development and testing in human physiological equivalent fluids of new hybrid biomaterials are presented. The role of water and its equilibrium modification in the human physiology is discussed and the swelling and sorption behavior in the physiological environment of a nanostructured and osteoconductive biomaterials based on Poly-Hydroxyl-Ethyl-Meth Acrylate matrix (pHEMA) filled with fumed amorphous nanosilica particles is presented. This material differently swells in presence of aqueous physiological solution fluid. Biological hybrid scaffolds for bone regeneration and growth made using synthetic materials able to correctly interact with the physiological fluids while inducing the growth of biological tissues may favor the birth in the medical field of a new class of hybrid materials. Our multidisciplinary approach explores in the this paper, novel ideas in modeling, design and fabrication of new nanostructured scaffolding biomaterials with enhanced functionality and improved interaction with OB cells
Hybrid ceramo-polymeric nanocomposite for biomimetic scaffolds design and preparation
No full textBiomimetics, biomechanics and tissue engineering are three multidisciplinary fields that have been contemplated in this research to attain the objective of improving prosthetic implants reliability. Since testing and mathematical methods are closely interlaced, a promising approach seemed to be the combination of in vitro and in vivo experiments with computer simulations (in silico). An innovative biomimetics and biomechanics approach and new synthetic structure providing a microenvironment, which is mechanically coherent and nutrient conducive for tissue osteoblast cell cultures used in regenerative medicine, are presented. The novel hybrid ceramo-polymeric nanocomposites are mutually investigated by Finite Element Analysis (FEA) biomimetic modelling, anatomic reconstruction, quantitative-computed-tomography characterization, computer design of tissue scaffold. The starting base materials are a class of innovative highly bioactive hybrid ceramopolymeric materials set-up by the proponent research group that will be used as bioactive matrix for the preparation of in situ bio-mineralised tectostructured porous nanocomposites. This study treats biomimetics, biomechanics and tissue engineering as strongly correlated multidisciplinary fields combined to design bone tissue scaffolds. The growth, maintenance and ossification of bone are fundamental and are regulated by the mechanical cues that are imposed by physical activities: This biomimetical/biomechanical approach will be pursued in designing the experimental procedures for in vitro scaffold mineralization and ossification. Bio-tissue mathematical modelling serves as a central repository to interface design, simulation and tissue fabrication. Finite element computer analyses will be used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and mandible thickness distributions using single and multi-phase continuum material representations of clinical cases of patients implanted with the traditional protocols. New protocols will be hypothesises for the use of the new biologically tecto-structured hybrid materials
Biofidel FEA Modeling of Customized Hybrid Biological Hip Joint Prostheses, Part I: Biomechanical Behavior of Implanted Femur
No full textBiofidel femur Finite Element Models have been developed using specific combination of Computer Tomography segmentation and solid modeling software tools able to represent bone physiology and structural behavior. These biofidel Finite Element Models (FEM) is used to evaluate the modification of the physiological stress distribution in a prosthesized femur and to assess new design criteria for the development of biomimetic hybrid biological hip prostheses. The faithful models proposed allowed us to properly consider the not isotropic characteristics of the proximal epiphysis of the femur and for the isotropic behavior in diaphysis to explain the critical alterations of the stress distribution in a resected femur following the implantation of a traditional hip joint prostheses. It has been shown that a wide region of the femur diaphysis is completely shielded by the rigid prosthesis significantly altering the physiological stress distribution that should guaranty a healthy bone growth and regeneration
About homeopathy or «similia similibus curentur»
No full textHomeopathy or homoeopathy (from the Greek hómoios, “similar” and páthos, “suffering” or “disease”) is a science created by Samuel Hahnemann in 1796. The homeopathic practice rests on three principles: The similarity, the individualization of cases and the infinitesimal. The use of the infinitesimal was proposed by Hahnemann in the early nineteenth century with the publication of “Organon der Heilkunst” (Organon of the art of healing). The compounds used do not become homeopathic unless they respect the principle of similarity, according to which a patient should be treated with a substance producing experimentally in a healthy person symptoms similar to those presented by the affected person, use of the substance being adapted to the patient thanks to the principle of individualization according to which the homeopath analyzes all the symptoms of the person and not only those related to the disease. Substances chosen according to this method can be administered in non-toxic weighted doses, but most prescribers use them in dilutions, sometimes very large, which have previously been subjected to very high and very frequent vibrations. Although some clinical trials produce positive results, multiple systematic reviews indicate that this is due to chance, questionable research methods, or publication biases. Despite a certain popularity, the therapeutic efficacy of homeopathy has not been demonstrated as a general and permanent solution. The vast majority of the scientific and medical community considers that homeopathy is a pseudo-science coming into contradiction with current knowledge in chemistry and biology established after the fundamental principles of homeopathy themselves proposed more than two Centuries. In particular, they point out that certain homeopathic dilutions are such that the excipient no longer contains a single molecule of the diluted remedy and therefore can’t act chemically. Moreover, the fact that effects are observed is disputed by published meta-analyzes which conclude that homeopathy has not demonstrated its clinical efficacy beyond the placebo effect and yet, the Homeopathy works, despite some malicious feedback
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