scholarly journals Masked stereolithography of hydroxyapatite bioceramic scaffolds through an integrative approach: From powder tailoring to evaluation of 3D printed parts properties

2021 ◽  
Author(s):  
Pedro Navarrete-Segado ◽  
Mallorie Tourbin ◽  
Christine Frances ◽  
David Grossin
Keyword(s):  
Total Porosity ◽  
Living Cells ◽  
Degree Of Crystallinity ◽  
Integrative Approach ◽  
Sintering Process ◽  
Flow Transport ◽  
3D Printed ◽  
Formation Of Cracks ◽  
High Degree ◽  
Hydroxyapatite Phase

In this paper, the tailoring of hydroxyapatite powders properties for the preparation of highly hydroxyapatite-loaded photocurable organic slurries was discussed. A methodical study was conducted to investigate suspensions properties and processability to find the most outstanding formulation for the production of hydroxyapatite scaffolds by stereolithography-based additive manufacturing technique. A debinding-sintering process was designed to avoid the formation of cracks during the pyrolysis of the resin and sintering of the ceramic part. A total porosity of 35 vol. % was observed for the scaffolds with an interconnected macroporosity, which could facilitate the flow transport of nutrients necessary to maintain living cells. A compression strength of 4.9±0.3 MPa was obtained for the specimens printed diagonally (45º to the printing stage surface). A slow degradation rate was shown for the printed parts mainly due to the high degree of crystallinity and the intrinsic stability of the hydroxyapatite phase. Our findings indicate that the tailoring of hydroxyapatite powders is needed for better processability as filler in photocurable suspensions. Moreover, it was demonstrated the feasibility of printing hydroxyapatite parts showing promising results for their application in surgery in the case of minor or non-load bearing implants requiring slow resorption properties.

INTERDISCIPLINARY LINKS, INTEGRATIVE APPROACH,HEURISTIC METHODS AND ARTIFICIAL INTELLIGENCE IN THE MANAGEMENT OF INNOVATION - PART 1

2018 ◽  
Vol 28 (5) ◽  
pp. 1527-1532
Author(s):  
Hristo Patev
Keyword(s):  
Artificial Intelligence ◽  
Production Systems ◽  
Innovation Management ◽  
Integrative Approach ◽  
Heuristic Methods ◽  
Organizational Renewal ◽  
Innovation Activities ◽  
Management Of Innovation ◽  
Inventive Activity ◽  
High Degree

In this first work, out of the total of twenty-four, are considered: Integrative approach, interdisciplinary relations and transnational language in the technical and economic fundament of engineering and management, for the purpose of competitive innovation and successful business. Approaches to develop the innovation with a high degree of complexity. Interactive heuristic methods and algorithms for inventive activity, for inspiring and developing new industrial products and services for households and production systems. Implementing an effective business vocabulary for organizational renewal. Introduction of gaming and "art" methods in innovation management. Intensifying innovation activities through an attempt to introduce artificial intelligence into teamwork, with simultaneous implementation of an engineering and non-engineering approach.

scholarly journals Synthesis and Characterization of Nano-Sized 4-Aminosalicylic Acid–Sulfamethazine Cocrystals

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 277 ◽  
Author(s):  
Ala’ Salem ◽  
Anna Takácsi-Nagy ◽  
Sándor Nagy ◽  
Alexandra Hagymási ◽  
Fruzsina Gősi ◽  
...  
Keyword(s):  
High Power ◽  
Active Pharmaceutical Ingredient ◽  
Polymorphic Form ◽  
Degree Of Crystallinity ◽  
Dissolution Enhancement ◽  
Aminosalicylic Acid ◽  
Nano Technology ◽  
Power Ultrasound ◽  
High Power Ultrasound ◽  
High Degree

Drug–drug cocrystals are formulated to produce combined medication, not just to modulate active pharmaceutical ingredient (API) properties. Nano-crystals adjust the pharmacokinetic properties and enhance the dissolution of APIs. Nano-cocrystals seem to enhance API properties by combining the benefits of both technologies. Despite the promising opportunities of nano-sized cocrystals, the research at the interface of nano-technology and cocrystals has, however, been described to be in its infancy. In this study, high-pressure homogenization (HPH) and high-power ultrasound were used to prepare nano-sized cocrystals of 4-aminosalysilic acid and sulfamethazine in order to establish differences between the two methods in terms of cocrystal size, morphology, polymorphic form, and dissolution rate enhancement. It was found that both methods resulted in the formation of form I cocrystals with a high degree of crystallinity. HPH yielded nano-sized cocrystals, while those prepared by high-power ultrasound were in the micro-size range. Furthermore, HPH produced smaller-size cocrystals with a narrow size distribution when a higher pressure was used. Cocrystals appeared to be needle-like when prepared by HPH compared to those prepared by high-power ultrasound, which had a different morphology. The highest dissolution enhancement was observed in cocrystals prepared by HPH; however, both micro- and nano-sized cocrystals enhanced the dissolution of sulfamethazine.

scholarly journals CYTOPLASMIC DNA SYNTHESIS IN AMOEBA PROTEUS

1962 ◽  
Vol 15 (3) ◽  
pp. 525-534 ◽  
Author(s):  
M. Rabinovitch ◽  
W. Plaut
Keyword(s):  
Dna Synthesis ◽  
Tritiated Thymidine ◽  
Amoeba Proteus ◽  
Living Cells ◽  
Large Numbers ◽  
Cytoplasmic Dna ◽  
Basic Dyes ◽  
Nuclease Digestion ◽  
High Degree ◽  
Very High

The incorporation of tritiated thymidine in Amoeba proteus was reinvestigated in order to see if it could be associated with microscopically detectable structures. Staining experiments with basic dyes, including the fluorochrome acridine orange, revealed the presence of large numbers of 0.3 to 0.5 µ particles in the cytoplasm of all cells studied. The effect of nuclease digestion on the dye affinity of the particles suggests that they contain DNA as well as RNA. Centrifugation of living cells at 10,000 g leads to the sedimentation of the particles in the centrifugal third of the ameba near the nucleus. Analysis of centrifuged cells which had been incubated with H3-thymidine showed a very high degree of correlation between the location of the nucleic acid-containing granules and that of acid-insoluble, deoxyribonuclease-sensitive labeled molecules and leads to the conclusion that cytoplasmic DNA synthesis in Amoeba proteus occurs in association with these particles.

scholarly journals Biomaterials – Novel Advances in Nasal Medical Implants, 3D Printing Applications

2021 ◽  
pp. 52-64
Author(s):  
T. M. Amulya ◽  
K. G. Siree ◽  
T. M. Pramod Kumar ◽  
M. B. Bharathi ◽  
K. Divith ◽  
...  
Keyword(s):  
3D Printing ◽  
Tissue Loss ◽  
Medical Implants ◽  
Anatomical Structures ◽  
Regulatory Aspects ◽  
3D Printed ◽  
Targeting Ability ◽  
Soft Tissue Loss ◽  
Biodegradable Biomaterials ◽  
High Degree

The scope and applications of biomaterials have spread out throughout a broad spectrum. Particularly in pharmacy, biomaterials are an attractive choice because they can be modified to decrease toxicity, increase the targeting ability among many other aspects of drug delivery. Extensive studies have led to the development of many metal-based, ceramic, biocompatible and biodegradable biomaterials for medical purposes among many others. The utilization of 3D printing in this discipline is a very novel research subject with infinite potential. Personalized and customized nasal implants are a great option to increase patient compliance and 3D printed accurate anatomical structures are rendered to be effective tools of learning. One of the disadvantages of biomaterial-based implants is the formation of a thick fibrous capsule formation around the implant, others being breakage, soft tissue loss and so on. Regulatory aspects are less explored for nasal implants. 3D printing is a unique technique that allows for a high degree of customisation in pharmacy, dentistry and in designing of medical devices. Current research in 3D printing indicates towards reproducing an organ in the form of a chip; paving the way for more studies and opportunities to perfecting the existing technique.

A model-driven framework for multi-paradigm modeling and holistic simulation of healthcare systems

SIMULATION ◽  
2017 ◽  
Vol 94 (3) ◽  
pp. 235-257 ◽  
Author(s):  
Ignace Djitog ◽  
Hamzat O Aliyu ◽  
Mamadou K Traoré
Keyword(s):  
Model Transformation ◽  
Healthcare Systems ◽  
Integrative Approach ◽  
Efficient Design ◽  
Model Driven ◽  
Dynamic Update ◽  
Modeling Methodology ◽  
Multiple Levels ◽  
High Degree ◽  
Answering Questions

The domain of healthcare is characterized by a high degree of complexity and a diversity of perspectives, and modelers are often confronted with the challenge of formulating a simulation model that captures this complexity in a systematic and manageable manner. Most often, the diverse perspectives of healthcare systems are studied in isolation and using specific formalisms. As it turns out, answering questions concerning behavioral properties of the overall system becomes difficult and therefore not sufficient for an efficient design and analysis of the system under study. In this article, we propose a framework for multi-paradigm modeling and holistic simulation of healthcare systems. We present a modeling methodology with a plethora of formalisms to allow the modeler to choose an appropriate formalism at a given level of abstraction while model transformation relates the different formalisms. Furthermore, we develop an integrative approach for the interactions between models of different perspectives through dynamic update of model output-to-parameter integration during concurrent simulations. Such an approach provides multiple levels of explanation for the same system, while offering, at the same time, an integrated view of the whole. The framework has successfully been applied to study part of the Nigerian healthcare system.

Environment Influence on the Properties of Functional Parts Made of HIPS Material

2021 ◽  
Vol 105 (1) ◽  
pp. 431-440
Author(s):  
Pavel Šafl ◽  
Jana Zimáková ◽  
Tomáš Binar
Keyword(s):  
Electron Microscope ◽  
3D Printing ◽  
Tensile Test ◽  
Uv Light ◽  
Starting Material ◽  
Climatic Chamber ◽  
3D Printed ◽  
Formation Of Cracks ◽  
Printed Materials ◽  
Degree Of Degradation

The aim of this work is to study the climatic influences on 3D printed materials. This study focuses on the HIPS material, which was chosen as the starting material for further studies. The material in the field of 3D printing is known for its rapid photooxidation, which results in the formation of cracks in the final product. A climatic chamber was used for degradation, in which UV light, heat and increased humidity were applied to the material. The degree of degradation was then checked by tensile test and electron microscope.

Heteroepitaxial Growth Of ZnO Films BY PLD

1997 ◽  
Vol 474 ◽  
Author(s):  
R. D. Vispute ◽  
V. Talyansky ◽  
Z. Trajanovic ◽  
S. Choopun ◽  
M. Downes ◽  
...  
Keyword(s):  
Oxygen Pressure ◽  
Surface Region ◽  
Optical Quality ◽  
Degree Of Crystallinity ◽  
Zno Films ◽  
Heteroepitaxial Growth ◽  
Near Surface ◽  
Ion Channeling ◽  
Deposition Parameters ◽  
High Degree

ABSTRACTHere we present our recent work on the fabrication of high crystalline and optical quality ZnO films on sapphire (001) by pulsed laser deposition. The influence of deposition parameters such as the substrate temperature, oxygen pressure, laser fluence, and pulse repetition rate on the crystalline quality of ZnO layers has been studied. The Ω-rocking curve FWHM of the (002) peak for the films grown at 750°, oxygen pressure 10−5 Torr was 0.17°. The XRD-Ф scans studies revealed that the films were epitaxial with a 30° rotation of the unit cell with respect to the sapphire to achieve a low energy configuration for epitaxial growth. The high degree of crystallinity was confirmed by ion channeling technique providing a minimum Rutherford backscattering yield of 2–3% in the near surface region (-2000Å). The atomic force microscopy revealed smooth hexagonal faceting of the films. The optical absorption edge measured by UV-Visible spectroscopy was sharp at 383 nm. Excellent crystalline properties of these epi-ZnO/sapphire heterostractures are thus promising for III-V nitride heteroepitaxy.

A Novel Spray Based Method for the Production of Semiconductor Nanocrystals

2005 ◽  
Vol 879 ◽  
Author(s):  
Lilac Amirav ◽  
Efrat Lifshitz
Keyword(s):  
Size Distribution ◽  
Semiconductor Nanocrystals ◽  
Average Diameter ◽  
Solute Concentration ◽  
Degree Of Crystallinity ◽  
Attractive Alternative ◽  
Spray Droplet ◽  
Zinc Blend ◽  
Semiconductor Nanoparticle ◽  
High Degree

AbstractWe present a novel spray based method for the formation and production of semiconductor nanocrystals that provides an attractive alternative to the commonly used epitaxial and colloidal procedures. According to this spray-based method, mainly thermospray, solutions of semiconductor salts are first sprayed into monodispersed droplets, which subsequently become solid nanoparticles by solvent evaporation. A semiconductor nanoparticle is produced from a single spray droplet upon the full vaporization of the solvent. The average diameter and size distribution of the final nanocrystals are controlled and determined by the solute concentration of the sprayed solution and by the droplet size, hence by the spray production parameters. The spray-produced nanocrystals are collected on any selected solid support. Representative results, shown in this paper, reveal the formation of CdS nanocrystals in the size range of 3 to 6 nanometer and with a size distribution of as low as five percents. A further structural analysis of these nanocrystals showed that they were formed in the zinc blend phase with high degree of crystallinity.

Heteroepitaxial Growth of Ba0.5Sr0.5TiO3/SrRuO3 on YSZ/Si by Off-Axis Sputtering

1994 ◽  
Vol 361 ◽  
Author(s):  
S.Y. Hou ◽  
J. Kwo ◽  
R.K. Watts ◽  
J.-Y. Cheng ◽  
R.J. Cava ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Degree Of Crystallinity ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Dielectric Constant And Loss ◽  
Bst Films ◽  
High Degree ◽  
Room Temperature Dielectric Constant

ABSTRACTWe demonstrate an epitaxial heterostructure of Ba0.5Sr0.5 TiO3/SrRuO3/YSZ on Si for potential charge storage applications. The dielectric Ba0.5Sr0.5TiO3 (BST) and conductive oxide SrRuO3 are both grown (110) oriented on YSZ (100) buffered Si by 90° off-axis sputtering. These films showed a high degree of crystallinity with minimal interdiffusion at the interfaces as examined by X-ray diffraction, Rutherford backscattering spectroscopy, and cross-section transmission electron microscopy. The in-plane epitaxial alignment of the films is BST/SRO 〈111〉 // YSZ 〈110〉 with a four-fold degeneracy. The dielectric constant and loss tangent of the epi-BST films are 360 and 0.01 at 10 kHz. The leakage current density is < 4×10∼−7 A/cm2 at 1 V. The room temperature dielectric constant (ε) of the BST films shows a roll-off in the 1–10 MHz range. This is attributed to the existence of a series resistance in the measurement circuit, which likely arises from the SrRuO3 electrode.

Phase Behavior and Properties of Polyurethane-PVC Blends and Fibers

1999 ◽  
Vol 72 (4) ◽  
pp. 587-601 ◽  
Author(s):  
Zoran S. Petrović ◽  
Ivan Javni ◽  
Jonathan Shull ◽  
Alan Waddon
Keyword(s):  
Thermomechanical Analysis ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Polyurethane Elastomer ◽  
Scanning Calorimetry ◽  
Polyester Urethane ◽  
Elastomeric Matrix ◽  
Low Concentrations ◽  
Rigid Poly ◽  
High Degree

Abstract A polyester urethane elastomer is blended with rigid poly(vinyl chloride) (PVC) and the miscibility of the components studied over the entire range of compositions. The polyurethane elastomer was a block copolymer with a low degree of crystallinity, while PVC was practically amorphous. Differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA) methods showed that polyester urethanes were partially miscible with PVC since two distinct glass transitions, which changed with the change of concentration of components, were observed. Although the PVC content was varied from 0–100%, the aim of the work was to examine if PVC at low concentrations would form fibrils in the urethane matrix and act as a reinforcing agent for the polyurethane elastomer. The morphology of the blends was studied by scanning electron microscopy and x-ray scattering. The blends were then spun into fibers to force the dispersed phase to elongate and form fibrils (draw ratio was about 100). A high degree of miscibility is obtained at low concentration of either of the components. The PVC phase in fibers spun from the blends have higher glass-transition temperature (Tg) than in isotropic blends, presumably due to increased orientation. No fibrillation of the rigid phase in the elastomeric matrix could be observed. The fibers displayed higher strengths but lower elongation at break than the isotropic blends of the same composition. Intermeshing morphology (at about 50/50 concentration) gave the lowest strengths.

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