A One-Step Method to Fabricate PLLA Scaffolds With Deposition of Bioactive Hydroxyapatite and Collagen Using Ice-Based Microporogens

2009 ◽  
Author(s):  
Yun Chen ◽  
Jiashen Li ◽  
Rocky S. Tuan ◽  
Arthur F. T. Mak
Keyword(s):  
Tissue Engineering ◽  
Single Step ◽  
Step Method ◽  
Step Process ◽  
Collagen Coating ◽  
One Step ◽  
Bioactive Agents

Scaffolding is an essential issue in tissue engineering. We have recently developed an approach to generate HA/collagen coated poly(lactic-glycolic acids) scaffolds using a porogen-leaching method [1]. The approach involves a two-step process with coating first on the paraffin microspheres and then using the coated microspheres both as the porogens and the vehicles to transfer the bioactive apatite/collagen coating. In this study, we describe an advancement of the porogen-based technology using ice-based microporogens to deposit multiple bioactive agents into the desired scaffold in a single step.

scholarly journals Single Step Process for Crystalline Ni-B Compounds

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1259 ◽  
Author(s):  
Mahboobeh Shahbazi ◽  
Henrietta Cathey ◽  
Natalia Danilova ◽  
Ian Mackinnon
Keyword(s):  
Single Phase ◽  
Single Step ◽  
Transformation Mechanism ◽  
Solid Reaction ◽  
Step Method ◽  
Step Process ◽  
Pressure Time ◽  
Autogenous Pressure ◽  
Higher Temperature ◽  
High Yields

Crystalline Ni2B, Ni3B, and Ni4B3 are synthesized by a single-step method using autogenous pressure from the reaction of NaBH4 and Ni precursors. The effect of reaction temperature, pressure, time, and starting materials on the composition of synthesized products, particle morphologies, and magnetic properties is demonstrated. High yields of Ni2B (>98%) are achieved at 2.3–3.4 MPa and ~670 °C over five hours. Crystalline Ni3B or Ni4B3 form in conjunction with Ni2B at higher temperature or higher autogenous pressure in proportions influenced by the ratios of initial reactants. For the same starting ratios of reactants, a longer reaction time or higher pressure shifts equilibria to lower yields of Ni2B. Using this approach, yields of ~88% Ni4B3 (single phase orthorhombic) and ~72% Ni3B are obtained for conditions 1.9 MPa < Pmax < 4.9 MPa and 670 °C < Tmax < 725 °C. Gas-solid reaction is the dominant transformation mechanism that results in formation of Ni2B at lower temperatures than conventional solid-state methods.

Progress in One-Pot Synthesis of Methyl Isobutyl Ketone Using Multifunctional Layered Based Catalysts

2013 ◽  
Vol 571 ◽  
pp. 169-196
Author(s):  
Nigamananda Das
Keyword(s):  
Methyl Isobutyl Ketone ◽  
Single Step ◽  
Methyl Isobutyl ◽  
Isobutyl Ketone ◽  
One Pot ◽  
Catalytic Systems ◽  
Step Process ◽  
One Pot Synthesis ◽  
Multifunctional Catalysts ◽  
One Step

Methyl isobutyl ketone (MIBK) is one of the most widely produced and used aliphatic ketones worldwide. The one-step MIBK process with no intermediate separation steps using multifunctional catalysts is an important development towards greener organic synthesis and generates tremendous interest among the researcher across the globe. The single step process is facile and more economically viable and has provided opportunity to develop new and improved catalyst systems capable of operating under mild conditions. A widely variety of catalytic systems have been used in one-step process during last three to four decades. The progress in one-pot synthesis of MIBK using different multifunctional catalysts with special reference to layered based catalysts was critically reviewed in this article.

scholarly journals 2D Rigid Benzoxazole-Linked Covalent Organic Framework Films with High-Strength, High-Modulus Mechanical Behavior

2020 ◽  
Author(s):  
Kristen Miller ◽  
Lawrence B. Alemany ◽  
Edwin L. Thomas ◽  
Eilaf Egap
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Single Step ◽  
Two Dimensions ◽  
Free Standing ◽  
Step Process ◽  
Axial Tensile ◽  
Solution Cast ◽  
One Step ◽  
Rigid Rod

<p>Two-dimensional (2D) benzoxazole-linked covalent organic frameworks (COFs) provide an opportunity to incorporate the strength and modulus of corresponding 1D rigid-rod polymers into multiple directions by extending covalent bonding into two dimensions while simultaneously reducing density. Thus far, this potential has been elusive because of the challenge of producing high-quality COF films, particularly those with irreversible, rigid benzazole linkages. The majority of COF syntheses use a single-step process approach where polymerization occurs faster than crystallization and typically result in a poorly ordered and insoluble powder. Here, we present a one-step synthesis and two-step process that allows the deposition of a uniform intermediate film via reversible, non-covalent interactions. This network then undergoes an annealing step that facilitates the irreversible conversion to 2D covalently-bonded polymer product. The resulting films are semi-crystalline with platelet-like crystals embedded in an amorphous matrix with sharp crystal-amorphous interfaces. By this approach, we achieve free-standing films for which we demonstrate the first example of mechanical testing of benzazole-linked COFs. These initial films have promising mechanical properties with an in-plane ultimate tensile strength of nearly 50 MPa and axial tensile and transverse compressive elastic moduli on the scale of several GPa. These mechanical properties already rival the performance of solution-cast films of 1D polybenzoxazole (PBO).<i></i></p>

A Facile One Step Synthesis of 3-(2-oxo-2H-chromen-3-yl)-indeno-[2,1-c]pyridazin-9-one

2005 ◽  
Vol 2005 (4) ◽  
pp. 267-269 ◽  
Author(s):  
V. Rajeswar Rao ◽  
P. Vijaya Kumar
Keyword(s):  
Acetic Acid ◽  
Hydrazine Hydrate ◽  
Single Step ◽  
Step Process ◽  
One Step

3-Acetylcoumarins (1) on reaction with ninhydrin (2) in acetic acid followed by treatment of in situ formed 2-hydroxy-2-[2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl]indan-1,3-diones (3) with hydrazine hydrate resulted in the formation of corresponding 3-(2-oxo-2H-chromen-3-yl)-indeno[2,1-c]pyridazin-9-ones (4) in a single step with an excellent yields. The structures of newly synthesised compounds (4) were confirmed by unambiguous synthesis involving a two step process from 3-acetylcoumarins.

scholarly journals 2D Rigid Benzoxazole-Linked Covalent Organic Framework Films with High-Strength, High-Modulus Mechanical Behavior

2020 ◽  
Author(s):  
Kristen Miller ◽  
Lawrence B. Alemany ◽  
Edwin L. Thomas ◽  
Eilaf Egap
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Single Step ◽  
Two Dimensions ◽  
Free Standing ◽  
Step Process ◽  
Axial Tensile ◽  
Solution Cast ◽  
One Step ◽  
Rigid Rod

<p>Two-dimensional (2D) benzoxazole-linked covalent organic frameworks (COFs) provide an opportunity to incorporate the strength and modulus of corresponding 1D rigid-rod polymers into multiple directions by extending covalent bonding into two dimensions while simultaneously reducing density. Thus far, this potential has been elusive because of the challenge of producing high-quality COF films, particularly those with irreversible, rigid benzazole linkages. The majority of COF syntheses use a single-step process approach where polymerization occurs faster than crystallization and typically result in a poorly ordered and insoluble powder. Here, we present a one-step synthesis and two-step process that allows the deposition of a uniform intermediate film via reversible, non-covalent interactions. This network then undergoes an annealing step that facilitates the irreversible conversion to 2D covalently-bonded polymer product. The resulting films are semi-crystalline with platelet-like crystals embedded in an amorphous matrix with sharp crystal-amorphous interfaces. By this approach, we achieve free-standing films for which we demonstrate the first example of mechanical testing of benzazole-linked COFs. These initial films have promising mechanical properties with an in-plane ultimate tensile strength of nearly 50 MPa and axial tensile and transverse compressive elastic moduli on the scale of several GPa. These mechanical properties already rival the performance of solution-cast films of 1D polybenzoxazole (PBO).<i></i></p>

scholarly journals Single step electrodeposition process using ionic liquid to grow highly luminescent silicon/rare earth (Er, Tb) thin films with tunable composition

RSC Advances ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 3789-3797 ◽  
Author(s):  
Shibin Thomas ◽  
Jeremy Mallet ◽  
Hervé Rinnert ◽  
Michael Molinari
Keyword(s):  
Thin Films ◽  
Ionic Liquid ◽  
Rare Earth ◽  
Room Temperature ◽  
Single Step ◽  
Room Temperature Ionic Liquid ◽  
Step Method ◽  
Electrodeposition Process ◽  
One Step

A one-step method for the electrodeposition of silicon–erbium (Si/Er) and silicon–terbium (Si/Tb) thin films using room temperature ionic liquid (RTIL) has been successfully developed.

Purification of Urokinase from Complex Mixtures Using Immobilized Monoclonal Antibody Against Urokinase Light Chain

1983 ◽  
Vol 49 (01) ◽  
pp. 024-027 ◽  
Author(s):  
David Vetterlein ◽  
Gary J Calton
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Culture Media ◽  
Biological Fluids ◽  
Single Step ◽  
High Yield ◽  
Step Method ◽  
Commercial Preparation ◽  
E Coli ◽  
Tissue Culture Media

SummaryThe preparation of a monoclonal antibody (MAB) against high molecular weight (HMW) urokinase light chain (20,000 Mr) is described. This MAB was immobilized and the resulting immunosorbent was used to isolate urokinase starting with an impure commercial preparation, fresh urine, spent tissue culture media, or E. coli broth without preliminary dialysis or concentration steps. Monospecific antibodies appear to provide a rapid single step method of purifying urokinase, in high yield, from a variety of biological fluids.

Effect of Dynamic Crosslinking on Mechanical Properties of PP/EPDM Blends

1993 ◽  
Vol 58 (11) ◽  
pp. 2642-2650 ◽  
Author(s):  
Zdeněk Kruliš ◽  
Ivan Fortelný ◽  
Josef Kovář
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Shear Modulus ◽  
High Impact ◽  
Necessary Condition ◽  
Step Method ◽  
Melt Mixing ◽  
One Step ◽  
High Impact Strength ◽  
Dynamic Curing

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

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