scholarly journals Influence of the tooth position, guided sleeve height, supporting length, manufacturing methods, and resin E‐modulus on the in‐vitro accuracy of surgical implant guides in a free end situation

2021 ◽  
Author(s):  
Andreas Keßler ◽  
Vinzenz Le ◽  
Matthias Folwaczny
Keyword(s):  
Surgical Implant ◽  
Tooth Position ◽  
Manufacturing Methods

scholarly journals Hybrid manufacturing strategies for tissue engineering scaffolds using methacrylate functionalised poly(glycerol sebacate)

2020 ◽  
Vol 34 (8) ◽  
pp. 1114-1130 ◽  
Author(s):  
Samand Pashneh-Tala ◽  
Robert Moorehead ◽  
Frederik Claeyssens
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Mechanical Performance ◽  
Hybrid Manufacturing ◽  
Tissue Engineering Scaffolds ◽  
Spatially Resolved ◽  
Primary Fibroblasts ◽  
Manufacturing Methods ◽  
Porous Poly

Poly(glycerol sebacate) is an attractive biomaterial for tissue engineering due to its biocompatibility, elasticity and rapid degradation rate. However, poly(glycerol sebacate) requires harsh processing conditions, involving high temperatures and vacuum for extended periods, to produce an insoluble polymer matrix. These conditions make generating accurate and intricate geometries from poly(glycerol sebacate), such as those required for tissue engineering scaffolds, difficult. Functionalising poly(glycerol sebacate) with methacrylate groups produces a photocurable polymer, poly(glycerol sebacate)-methacrylate, which can be rapidly crosslinked into an insoluble matrix. Capitalising on these improved processing capabilities, here, we present a variety of approaches for fabricating porous tissue engineering scaffolds from poly(glycerol sebacate)-methacrylate using sucrose porogen leaching combined with other manufacturing methods. Mould-based techniques were used to produce porous disk-shaped and tubular scaffolds. Porogen size was shown to influence scaffold porosity and mechanical performance, and the porous poly(glycerol sebacate)-methacrylate scaffolds supported the proliferation of primary fibroblasts in vitro. Additionally, scaffolds with spatially variable mechanical properties were generated by combining variants of poly(glycerol sebacate)-methacrylate with different stiffness. Finally, subtractive and additive manufacturing methods were developed with the capabilities to generate porous poly(glycerol sebacate)-methacrylate scaffolds from digital designs. These hybrid manufacturing strategies offer the ability to produce accurate macroscale poly(glycerol sebacate)-methacrylate scaffolds with tailored microscale porosity and spatially resolved mechanical properties suitable for a broad range of applications across tissue engineering.

scholarly journals Blood manufacturing methods affect red blood cell product characteristics and immunomodulatory activity

2018 ◽  
Vol 2 (18) ◽  
pp. 2296-2306 ◽  
Author(s):  
Ruqayyah J. Almizraq ◽  
Philip J. Norris ◽  
Heather Inglis ◽  
Somaang Menocha ◽  
Mathijs R. Wirtz ◽  
...  
Keyword(s):  
Whole Blood ◽  
Cytokine Production ◽  
White Blood Cells ◽  
Adverse Outcomes ◽  
Immunomodulatory Activity ◽  
Red Cell ◽  
Cell Of Origin ◽  
Increased Risk ◽  
Manufacturing Methods

AbstractTransfusion of red cell concentrates (RCCs) is associated with increased risk of adverse outcomes that may be affected by different blood manufacturing methods and the presence of extracellular vesicles (EVs). We investigated the effect of different manufacturing methods on hemolysis, residual cells, cell-derived EVs, and immunomodulatory effects on monocyte activity. Thirty-two RCC units produced using whole blood filtration (WBF), red cell filtration (RCF), apheresis-derived (AD), and whole blood–derived (WBD) methods were examined (n = 8 per method). Residual platelet and white blood cells (WBCs) and the concentration, cell of origin, and characterization of EVs in RCC supernatants were assessed in fresh and stored supernatants. Immunomodulatory activity of RCC supernatants was assessed by quantifying monocyte cytokine production capacity in an in vitro transfusion model. RCF units yielded the lowest number of platelet and WBC-derived EVs, whereas the highest number of platelet EVs was in AD (day 5) and in WBD (day 42). The number of small EVs (<200 nm) was greater than large EVs (≥200 nm) in all tested supernatants, and the highest level of small EVs were in AD units. Immunomodulatory activity was mixed, with evidence of both inflammatory and immunosuppressive effects. Monocytes produced more inflammatory interleukin-8 after exposure to fresh WBF or expired WBD supernatants. Exposure to supernatants from AD and WBD RCC suppressed monocyte lipopolysaccharide-induced cytokine production. Manufacturing methods significantly affect RCC unit EV characteristics and are associated with an immunomodulatory effect of RCC supernatants, which may affect the quality and safety of RCCs.

scholarly journals Biphasic Dissolution as an Exploratory Method during Early Drug Product Development

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 420 ◽  
Author(s):  
Daniela Amaral Silva ◽  
Jozef Al-Gousous ◽  
Neal M. Davies ◽  
Nadia Bou Chacra ◽  
Gregory K. Webster ◽  
...  
Keyword(s):  
Product Development ◽  
Buffer Capacity ◽  
Drug Product ◽  
The United States ◽  
Drug Formulation ◽  
Discriminatory Power ◽  
Oral Dosage ◽  
Dissolution Test ◽  
Manufacturing Methods

Dissolution testing is a major tool used to assess a drug product’s performance and as a quality control test for solid oral dosage forms. However, compendial equipment and methods may lack discriminatory power and the ability to simulate aspects of in vivo dissolution. Using low buffer capacity media combined with an absorptive phase (biphasic dissolution) increases the physiologic relevance of in vitro testing. The purpose of this study was to use non-compendial and compendial dissolution test conditions to evaluate the in vitro performance of different formulations. The United States Pharmacopeia (USP)-recommended dissolution method greatly lacked discriminatory power, whereas low buffer capacity media discriminated between manufacturing methods. The use of an absorptive phase in the biphasic dissolution test assisted in controlling the medium pH due to the drug removal from the aqueous medium. Hence, the applied non-compendial methods were more discriminative to drug formulation differences and manufacturing methods than conventional dissolution conditions. In this study, it was demonstrated how biphasic dissolution and a low buffer capacity can be used to assess in vitro drug product performance differences. This can be a valuable approach during the early stages of drug product development for investigating in vitro drug release with improved physiological relevance.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

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