scholarly journals Adhesion of mussel foot proteins to different substrate surfaces

2013 ◽  
Vol 10 (79) ◽  
pp. 20120759 ◽  
Author(s):  
Qingye Lu ◽  
Eric Danner ◽  
J. Herbert Waite ◽  
Jacob N. Israelachvili ◽  
Hongbo Zeng ◽  
...  
Keyword(s):  
Contact Time ◽  
Substrate Surface ◽  
Surface Forces ◽  
Recent Analysis ◽  
Surface Forces Apparatus ◽  
Substrate Surfaces ◽  
New Generation ◽  
Surface Chemistries ◽  
Adhesive Materials

Mussel foot proteins (mfps) have been investigated as a source of inspiration for the design of underwater coatings and adhesives. Recent analysis of various mfps by a surface forces apparatus (SFA) revealed that mfp-1 functions as a coating, whereas mfp-3 and mfp-5 resemble adhesive primers on mica surfaces. To further refine and elaborate the surface properties of mfps, the force–distance profiles of the interactions between thin mfp (i.e. mfp-1, mfp-3 or mfp-5) films and four different surface chemistries, namely mica, silicon dioxide, polymethylmethacrylate and polystyrene, were measured by an SFA. The results indicate that the adhesion was exquisitely dependent on the mfp tested, the substrate surface chemistry and the contact time. Such studies are essential for understanding the adhesive versatility of mfps and related/similar adhesion proteins, and for translating this versatility into a new generation of coatings and (including in vivo ) adhesive materials.

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

Flavonoids as P-gp Inhibitors: A Systematic Review of SARs

2019 ◽  
Vol 26 (25) ◽  
pp. 4799-4831 ◽  
Author(s):  
Jiahua Cui ◽  
Xiaoyang Liu ◽  
Larry M.C. Chow
Keyword(s):  
Molecular Mechanisms ◽  
Metastatic Cancer ◽  
Drug Candidates ◽  
Chemical Structures ◽  
Transporter Family ◽  
Promising Area ◽  
New Generation ◽  
Nontoxic Inhibitors

P-glycoprotein, also known as ABCB1 in the ABC transporter family, confers the simultaneous resistance of metastatic cancer cells towards various anticancer drugs with different targets and diverse chemical structures. The exploration of safe and specific inhibitors of this pump has always been the pursuit of scientists for the past four decades. Naturally occurring flavonoids as benzopyrone derivatives were recognized as a class of nontoxic inhibitors of P-gp. The recent advent of synthetic flavonoid dimer FD18, as a potent P-gp modulator in reversing multidrug resistance both in vitro and in vivo, specifically targeted the pseudodimeric structure of the drug transporter and represented a new generation of inhibitors with high transporter binding affinity and low toxicity. This review concerned the recent updates on the structure-activity relationships of flavonoids as P-gp inhibitors, the molecular mechanisms of their action and their ability to overcome P-gp-mediated MDR in preclinical studies. It had crucial implications on the discovery of new drug candidates that modulated the efflux of ABC transporters and also provided some clues for the future development in this promising area.

Imaging the condensation and evaporation of molecularly thin ethanol films with surface forces apparatus

2014 ◽  
Vol 85 (1) ◽  
pp. 013702 ◽  
Author(s):  
Gutian Zhao ◽  
Qiyan Tan ◽  
Li Xiang ◽  
Di Zhang ◽  
Zhonghua Ni ◽  
...  
Keyword(s):  
Surface Forces ◽  
Surface Forces Apparatus

scholarly journals New-generation osteoplastic materials based on biological and synthetic matrices

2021 ◽  
Vol 16 (1) ◽  
pp. 36-54
Author(s):  
D. D. Lykoshin ◽  
V. V. Zaitsev ◽  
M. A. Kostromina ◽  
R. S. Esipov
Keyword(s):  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Biologically Active ◽  
Side Reactions ◽  
Prolonged Release ◽  
Pharmaceutical Substances ◽  
Surgical Implants ◽  
Analytical Review ◽  
New Generation

Objectives. The purpose of this analytical review is to evaluate the market for osteoplastic materials and surgical implants, as well as study the features of new-generation materials and the results of clinical applications.Methods. This review summarizes the volumes of research articles presented in the electronic database PubMed and eLIBRARY. A total of 129 scientific articles related to biological systems, calcium phosphate, polymer, and biocomposite matrices as carriers of pharmaceutical substances, primary recombinant protein osteoinductors, antibiotics, and biologically active chemical reagents were analyzed and summarized. The search depth was 10 years.Results. Demineralized bone matrix constitutes 26% of all types of osteoplastic matrices used globally in surgical osteology, which includes neurosurgery, traumatology and orthopedics, dentistry, and maxillofacial and pediatric surgery. Among the matrices, polymer and biocomposite matrices are outstanding. Special attention is paid to the possibility of immobilizing osteogenic factors and target pharmaceutical substances on the scaffold material to achieve controlled and prolonged release at the site of surgical implantation. Polymeric and biocomposite materials can retard the release of pharmaceutical substances at the implantation site, promoting a decrease in the toxicity and an improvement in the therapeutic effect. The use of composite scaffolds of different compositions in vivo results in high osteogenesis, promotes the initialization of biomineralization, and enables the tuning of the degradation rate of the material.Conclusions. Osteoplastic materials of various compositions in combination with drugs showed accelerated regeneration and mineralization of bone tissue in vivo, excluding systemic side reactions. Furthermore, although some materials have already been registered as commercial drugs, a plethora of unresolved problems remain. Due to the limited clinical studies of materials for use on humans, there is still an insufficient understanding of the toxicity of materials, time of their resorption, speed of drug delivery, and the possible long-term adverse effects of using implants of different compositions.

scholarly journals Exploring heteroaromatic rings as a replacement for the labile amide of antiplasmodial pantothenamides

2020 ◽  
Author(s):  
Jinming Guan ◽  
Christina Spry ◽  
Erick T. Tjhin ◽  
Penghui Yang ◽  
Tanakorn Kittikool ◽  
...  
Keyword(s):  
Contact Time ◽  
High Selectivity ◽  
Amide Group ◽  
Antiplasmodial Activity ◽  
Time Data ◽  
Facile Synthesis ◽  
Isoxazole Derivative ◽  
Nanomolar Range

ABSTRACTThe Plasmodium parasites that cause malaria are adept at developing resistance to antimalarial drugs, necessitating the search for new antiplasmodials. Although several amide analogs of pantothenate (pantothenamides) show potent antiplasmodial activity, hydrolysis by pantetheinases (or vanins) present in blood rapidly inactivates them. We report herein the facile synthesis and biological activity of a small library of pantothenamide analogs in which the labile amide group is replaced with a variety of heteroaromatic rings. Several of the new analogs display antiplasmodial activity in the nanomolar range against P. falciparum and/or P. knowlesi in the presence of pantetheinase. A previously reported triazole and an isoxazole derivative presented here were further characterized and found to possess high selectivity indices, medium or high Caco-2 permeability, and medium or low microsomal clearance in vitro. Although we show here that the two compounds fail to suppress proliferation of P. berghei in vivo, pharmacokinetic and contact time data presented provide a benchmark for the compound profile required to achieve antiplasmodial activity in mice and should facilitate lead optimization.

scholarly journals Optimization of process parameters in the RF-DC plasma N2-H2 for AISI420 molds and dies

2019 ◽  
Author(s):  
Hengky Herdianto ◽  
Dionisius Johanes Djoko Herry Santjojo ◽  
Masruroh
Keyword(s):  
Process Parameters ◽  
Substrate Surface ◽  
Xrd Analysis ◽  
Iron Nitrides ◽  
Dc Plasma ◽  
Precision Forging ◽  
Optimization Of Process Parameters ◽  
Dc Bias ◽  
Substrate Surfaces

The RF-DC plasma N2-H2 was used to make precise AISI420 molds and dies have complex textured geometry. The quality of the molds and dies directly affect the quality of the produced parts. The excellent examples of molds were used for injection molding lenses and dies used for the precision forging of automotive drive train components. In this study, a temperature, DC bias, and duration as process parameters of the RF-DC plasma N2-H2 have been optimized for molds and dies fabrication. The mask-less micro-patterned method was utilized to draw the initial 2D micro patterns directly onto the AISI420 substrate surface. The unprinted substrate surfaces were selectively nitrided by the RF-DC plasma N2-H2 at 673 K for 5400 s by 70 Pa with hollow cathode device. Energy Dispersive X-ray was utilized to describe the nitrogen content distribution at the vicinity of the border between the unprinted surfaces. This exclusive nitrogen mapping proves that only the unprinted parts of the substrate have high content nitrogen solutes. XRD analysis was performed to investigate whether the iron nitrides were precipitated by RF-DC plasma N2-H2 in the AISI420.

Understanding the molecular interactions of lipopolysaccharides during E. coli initial adhesion with a surface forces apparatus

Soft Matter ◽  
2011 ◽  
Vol 7 (19) ◽  
pp. 9366 ◽  
Author(s):  
Qingye Lu ◽  
Jing Wang ◽  
Ali Faghihnejad ◽  
Hongbo Zeng ◽  
Yang Liu
Keyword(s):  
Molecular Interactions ◽  
Surface Forces ◽  
Surface Forces Apparatus ◽  
E Coli ◽  
Initial Adhesion
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