scholarly journals Polymer-Based Electrophoretic Deposition of Nonwovens for Medical Applications: The Effect of Carrier Structure, Solution, and Process Parameters

Marine Drugs ◽  
2021 ◽  
Vol 19 (10) ◽  
pp. 533
Author(s):  
Ewelina Pabjanczyk-Wlazlo ◽  
Nina Tarzynska ◽  
Anna Bednarowicz ◽  
Adam Puszkarz ◽  
Grzegorz Szparaga
Keyword(s):  
Process Parameters ◽  
Electrophoretic Deposition ◽  
Structural Characteristics ◽  
Complex Structure ◽  
Poly Lactic Acid ◽  
Medical Applications ◽  
Fibrous Materials ◽  
Surface Mass ◽  
Metallic Biomaterials ◽  
Molecular Structure Analysis

Hyaluronate and alginate are non-toxic and biocompatible polymers, which can be used for surface modification and functionalization of many kinds of materials. Electrophoretic deposition (EPD) has several advantages, including its versatility, simplicity, and ability to coat substrates with complex shapes, and is used for the creation of antimicrobial or hydrophobic coatings on metallic biomaterials, among other applications. However, its utilization for applying biopolymer layers on textiles is very limited due to the more complex structure and spatial characteristics of fibrous materials. The aim of this research was to analyze the effects of selected EPD process parameters and the structural characteristics of fibrous carriers on the kinetics of the process and the microscopic characteristics of the deposited layers. The influence of solution characteristics, process parameters, and carrier structures obtained using two different techniques (melt blown and spun-bonded) were analyzed. The morphology and structure of the created deposits were analyzed using scanning electron microscopy and computed tomography, and molecular structure analysis was performed with Fourier Transform Infrared spectroscopy. The surface mass and thickness of fibrous poly (lactic acid)-based carriers were analyzed in accordance with the respective standards. This study serves as a basis for discussion and further development of this method with regard to fibrous materials for medical applications.

scholarly journals Physico-Chemical and In Vitro Characterization of Chitosan-Based Microspheres Intended for Nasal Administration

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 608
Author(s):  
Csilla Bartos ◽  
Patrícia Varga ◽  
Piroska Szabó-Révész ◽  
Rita Ambrus
Keyword(s):  
Drug Delivery ◽  
Spray Drying ◽  
Process Parameters ◽  
Sodium Tripolyphosphate ◽  
Structural Characteristics ◽  
Nasal Administration ◽  
Drug Bioavailability ◽  
Intranasal Application ◽  
Spray Dried

The absorption of non-steroidal anti-inflammatory drugs (NSAIDs) through the nasal epithelium offers an innovative opportunity in the field of pain therapy. Thanks to the bonding of chitosan to the nasal mucosa and its permeability-enhancing effect, it is an excellent choice to formulate microspheres for the increase of drug bioavailability. The aim of our work includes the preparation of spray-dried cross-linked and non-cross-linked chitosan-based drug delivery systems for intranasal application, the optimization of spray-drying process parameters (inlet air temperature, pump rate), and the composition of samples. Cross-linked products were prepared by using different amounts of sodium tripolyphosphate. On top of these, the micrometric properties, the structural characteristics, the in vitro drug release, and the in vitro permeability of the products were studied. Spray-drying resulted in micronized chitosan particles (2–4 μm) regardless of the process parameters. The meloxicam (MEL)-containing microspheres showed nearly spherical habit, while MEL was present in a molecularly dispersed state. The highest dissolved (>90%) and permeated (~45 µg/cm2) MEL amount was detected from the non-cross-linked sample. Our results indicate that spray-dried MEL-containing chitosan microparticles may be recommended for the development of a novel drug delivery system to decrease acute pain or enhance analgesia by intranasal application.

scholarly journals A Multiple and Multi-Level Substructure Method for the Dynamics of Complex Structures

2021 ◽  
Vol 11 (12) ◽  
pp. 5570
Author(s):  
Binbin Wang ◽  
Jingze Liu ◽  
Zhifu Cao ◽  
Dahai Zhang ◽  
Dong Jiang
Keyword(s):  
Structural Characteristics ◽  
Complex Structure ◽  
Complex Structures ◽  
System Matrix ◽  
Substructure Method ◽  
Residual Structure ◽  
The Matrix ◽  
Multi Level ◽  
Fixed Interface ◽  
Selection Of

Based on the fixed interface component mode synthesis, a multiple and multi-level substructure method for the modeling of complex structures is proposed in this paper. Firstly, the residual structure is selected according to the structural characteristics of the assembled complex structure. Secondly, according to the assembly relationship, the parts assembled with the residual structure are divided into a group of substructures, which are named the first-level substructure, the parts assembled with the first-level substructure are divided into a second-level substructure, and consequently the multi-level substructure model is established. Next, the substructures are dynamically condensed and assembled on the boundary of the residual structure. Finally, the substructure system matrix, which is replicated from the matrix of repeated physical geometry, is obtained by preserving the main modes and the constrained modes and the system matrix of the last level of the substructure is assembled to the upper level of the substructure, one level up, until it is assembled in the residual structure. In this paper, an assembly structure with three panels and a gear box is adopted to verify the method by simulation and a rotor is used to experimentally verify the method. The results show that the proposed multiple and multi-level substructure modeling method is not unique to the selection of residual structures, and different classification methods do not affect the calculation accuracy. The selection of 50% external nodes can further improve the analysis efficiency while ensuring the calculation accuracy.

scholarly journals Influence of the process parameters on mechanical properties of the final parts obtained by selective laser sintering from PA2200 powder

2019 ◽  
Vol 299 ◽  
pp. 01001 ◽  
Author(s):  
Luciana Laura Dincă (Shamieh) ◽  
Nicoleta Mirela Popa ◽  
Nichita Larisa Milodin ◽  
Comsa Stanca ◽  
Doina Gheorghiu
Keyword(s):  
Process Parameters ◽  
Mechanical Characteristics ◽  
Selective Laser Sintering ◽  
Tensile Tests ◽  
Medical Applications ◽  
Medical Field ◽  
Preheating Temperature ◽  
Experimental Researches ◽  
Best Parameters ◽  
Different Parts

The paper describes how the process parameters affects the mechanical characteristics of laser selective sintered (SLS) parts used in applications of medical, automotive and aerospace fields. The greatest advantage of the additive manufacturing (AM) technology in the medical field is that it allows the use of the patient's medical CT images to obtain specific implants, providing high benefits for both patients and physicians. Despite its increasing use and advantages, the AM process has a series of problemssuch as: the difficulty in obtaining quality part, process interruption or manufacturing part failure. As such, there have been developed experimental researches in order to establish a correlation between the process parameters and the finished part properties. For this analysis, PA 2200 polyamide specimenswere obtained by SLS and subjected to tensile tests. The results correlate the process parameters, providing proof that the tensile properties of SLS specimen are dependent of orientation, position and preheating temperature. Based on the correlation between the process parameters and properties of the PA2200 polyamide, this paper provides a better understanding of the AM process and allows an anticipation onthe best parameters to be used on different parts, leading the optimizing of component properties for medical applications.

scholarly journals Spinnability and characteristics of polyoxymethylene-based core–sheath bicomponent fibers

2019 ◽  
Vol 14 ◽  
pp. 155892501985944
Author(s):  
Jitlada Boonlertsamut ◽  
Supaphorn Thumsorn ◽  
Toshikazu Umemura ◽  
Hiroyuki Hamada ◽  
Atsushi Sakuma
Keyword(s):  
Lactic Acid ◽  
Structural Characteristics ◽  
Core Material ◽  
Poly Lactic Acid ◽  
Bicomponent Fibers ◽  
Fiber Properties ◽  
The Core ◽  
The Impact ◽  
Fiber Processing ◽  
Selection Of

In this work, the spinning abilities of polyoxymethylene-based core–sheath bicomponent fibers were investigated. Bicomponent fibers were prepared using polyoxymethylene as the core material and poly(lactic acid) blended with polyoxymethylene or pure polyoxymethylene as sheath materials, and their characteristics were investigated and compared. Fiber properties such as elongation are important because they directly relate to the spinning performance during fiber processing. This work reports the impact of the composition designation of the core–sheath bicomponent fibers on the controllable stability of poly(lactic acid) in polyoxymethylene–poly(lactic acid) blends in the fibers, as well as the influence of the core–sheath material on the structure, fiber diameter and distribution, thermal stability, and mechanical properties of the core–sheath bicomponent fibers. It was found that the selection of core and sheath materials affected the structural characteristics of the fibers. The polyoxymethylene core–polyoxymethylene sheath (FV) fiber showed dimensional stability. However, the polyoxymethylene core–poly(lactic acid)/polyoxymethylene sheath (FT30) fiber provided the optimum limit of poly(lactic acid) content for controlling the stable properties of the core–sheath bicomponent fibers.

Influence of temperature dependence on the structural characteristics of polyoxymethylene/poly(lactic acid) blends by injection molding

2019 ◽  
Vol 39 (10) ◽  
pp. 944-953
Author(s):  
Jitlada Boonlertsamut ◽  
Suchalinee Mathurosemontri ◽  
Supaphorn Thumsorn ◽  
Toshikazu Umemura ◽  
Atsushi Sakuma
Keyword(s):  
Lactic Acid ◽  
Injection Molding ◽  
Crystal Size ◽  
Structural Characteristics ◽  
Growth Direction ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Mechanical And Thermal Properties ◽  
Molding Process ◽  
Microscopy Images

Abstract In this research, different strategies to modify the structure of polymer blends were investigated with the objective of adjusting the composition of polyoxymethylene (POM) and poly(lactic acid) (PLA) under typical processing conditions. POM shows a good balance of mechanical and thermal properties. However, this polymer is obtained from petrochemical sources, and in some markets, environmentally friendly materials are important. Blending POM with PLA preserves the advantages of POM while ensuring the bio-based content of PLA. POM/PLA blends were prepared by an injection molding process with various injection speeds of 10, 50, 100, and 1000 mm/s to ensure high ductility. Mechanical property analysis showed that the PLA content and processing temperatures are highly effective in modifying the stiffness of POM/PLA blends. The effect of crystallization on POM/PLA blends was assessed by varying the annealing time. High-magnification scanning electron microscopy images revealed that the gaps between fibrillar regions represent the growth direction of the PLA phase before it was removed. This was evidence for the effect of PLA on the crystallization of POM. The crystal size and crystalline volume also affected the structural characteristics of POM/PLA blends.

scholarly journals Surface Modifications of Biodegradable Metallic Foams for Medical Applications

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 819
Author(s):  
Renáta Oriňaková ◽  
Radka Gorejová ◽  
Zuzana Orságová Králová ◽  
Andrej Oriňak
Keyword(s):  
Bone Tissue ◽  
Surface Modifications ◽  
Metallic Foam ◽  
Future Research ◽  
Medical Applications ◽  
Metallic Foams ◽  
Preparation Methods ◽  
Processing Technologies ◽  
Metallic Biomaterials ◽  
Bonding Properties

Significant progress was achieved presently in the development of metallic foam-like materials improved by biocompatible coatings. Material properties of the iron, magnesium, zinc, and their alloys are promising for their uses in medical applications, especially for orthopedic and bone tissue purposes. Current processing technologies and a variety of modifications of the surface and composition facilitate the design of adjusted medical devices with desirable mechanical, morphological, and functional properties. This article reviews the recent progress in the design of advanced degradable metallic biomaterials perfected by different coatings: polymer, inorganic ceramic, and metallic. Appropriate coating of metallic foams could improve the biocompatibility, osteogenesis, and bone tissue-bonding properties. In this paper, a comprehensive review of different coating types used for the enhancement of one or several properties of biodegradable porous implants is given. An outline of the conventional preparation methods of metallic foams and a brief overview of different alloys for medical applications are also provided. In addition, current challenges and future research directions of processing and surface modifications of biodegradable metallic foams for medical applications are suggested.

Carbon Layer as a New Material for Optics

2004 ◽  
Vol 817 ◽  
Author(s):  
R. Clergereaux ◽  
D. Escaich ◽  
S. Martin ◽  
P. Raynaud ◽  
F. Gaillard
Keyword(s):  
Process Parameters ◽  
Structural Characteristics ◽  
Plasma Source ◽  
Carbon Layer ◽  
Plasma Power ◽  
Film Properties ◽  
Deposition Parameters ◽  
External Process ◽  
New Material ◽  
Highly Correlated

AbstractPlasma enhanced CVD produces carbon layers with various properties which are highly correlated to the different process parameters such as monomer structure, plasma type or plasma power. For example, the modification of monomer (CH4 to C4H10) or the plasma source and the increase of plasma power lead to an optical band-gap which runs from 0.9 to 4.3eV, a conductivity from 5·103 to 5·105S.m−1 and a refractive index from 1.47 to 2.76. Then, it is able to control the optical and electrical film properties from the external process parameters. This paper will thus be focused on the description of relation between deposition parameters, structural characteristics of material and film properties. These materials can then be used for optoelectronics applications.

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