A Novel Approach of Plasma Nitrocarburizing Using a Solid Carbon Active Screen – a Proof of Concept

2017 ◽  
Vol 72 (5) ◽  
pp. 254-259 ◽  
Author(s):  
I. Burlacov ◽  
S. Hamann ◽  
H.-J. Spies ◽  
A. Dalke ◽  
J. Röpcke ◽  
...  
Keyword(s):  
Solid Carbon ◽  
Proof Of Concept ◽  
Novel Approach ◽  
Plasma Nitrocarburizing ◽  
Active Screen

scholarly journals Effects of Plasma-Chemical Composition on AISI 316L Surface Modification by Active Screen Nitrocarburizing Using Gaseous and Solid Carbon Precursors

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1411
Author(s):  
Saeed M. Jafarpour ◽  
Andrei V. Pipa ◽  
Alexander Puth ◽  
Anke Dalke ◽  
Jürgen Röpcke ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Low Temperature ◽  
Austenitic Stainless Steels ◽  
Solid Carbon ◽  
Aisi 316L ◽  
Plasma Chemical ◽  
Temperature Plasma ◽  
Expanded Austenite ◽  
Plasma Nitrocarburizing ◽  
Active Screen

Low-temperature plasma nitrocarburizing treatments are applied to improve the surface properties of austenitic stainless steels by forming an expanded austenite layer without impairing the excellent corrosion resistance of the steel. Here, low-temperature active screen plasma nitrocarburizing (ASPNC) was investigated in an industrial-scale cold-wall reactor to compare the effects of two active screen materials: (i) a steel active screen with the addition of methane as a gaseous carbon-containing precursor and (ii) an active screen made of carbon-fibre-reinforced carbon (CFC) as a solid carbon precursor. By using both active screen materials, ASPNC treatments at variable plasma conditions were conducted using AISI 316L. Moreover, insight into the plasma-chemical composition of the H2-N2 plasma for both active screen materials was gained by laser absorption spectroscopy (LAS) combined with optical emission spectroscopy (OES). It was found that, in the case of a CFC active screen in a biased condition, the thickness of the nitrogen-expanded austenite layer increased, while the thickness of the carbon-expanded austenite layer decreased compared to the non-biased condition, in which the nitrogen- and carbon-expanded austenite layers had comparable thicknesses. Furthermore, the crucial role of biasing the workload to produce a thick and homogeneous expanded austenite layer by using a steel active screen was validated.

scholarly journals Use of Oxidative Stress Responses to Determine the Efficacy of Inactivation Treatments on Cryptosporidium Oocysts

2021 ◽  
Vol 9 (7) ◽  
pp. 1463
Author(s):  
Tamirat Tefera Temesgen ◽  
Kristoffer Relling Tysnes ◽  
Lucy Jane Robertson
Keyword(s):  
Oxidative Stress ◽  
Stress Responses ◽  
Target Genes ◽  
Cryptosporidium Oocyst ◽  
Drinking Water Treatment ◽  
Proof Of Concept ◽  
Environmental Matrices ◽  
Oocyst Wall ◽  
Novel Approach ◽  
Cryptosporidium Oocysts

Cryptosporidium oocysts are known for being very robust, and their prolonged survival in the environment has resulted in outbreaks of cryptosporidiosis associated with the consumption of contaminated water or food. Although inactivation methods used for drinking water treatment, such as UV irradiation, can inactivate Cryptosporidium oocysts, they are not necessarily suitable for use with other environmental matrices, such as food. In order to identify alternative ways to inactivate Cryptosporidium oocysts, improved methods for viability assessment are needed. Here we describe a proof of concept for a novel approach for determining how effective inactivation treatments are at killing pathogens, such as the parasite Cryptosporidium. RNA sequencing was used to identify potential up-regulated target genes induced by oxidative stress, and a reverse transcription quantitative PCR (RT-qPCR) protocol was developed to assess their up-regulation following exposure to different induction treatments. Accordingly, RT-qPCR protocols targeting thioredoxin and Cryptosporidium oocyst wall protein 7 (COWP7) genes were evaluated on mixtures of viable and inactivated oocysts, and on oocysts subjected to various potential inactivation treatments such as freezing and chlorination. The results from the present proof-of-concept experiments indicate that this could be a useful tool in efforts towards assessing potential technologies for inactivating Cryptosporidium in different environmental matrices. Furthermore, this approach could also be used for similar investigations with other pathogens.

Practicality Assessment of a Frugal Nanoparticle Generator: Opening doors to Nano Pharmaceuticals for the researchers and students of underprivileged academic institutions.

2021 ◽  
Vol 17 ◽  
Author(s):  
Swayamprakash Patel ◽  
Ashish Patel ◽  
Mruduka Patel ◽  
Umang Shah ◽  
Mehul Patel ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Organic Solvent ◽  
Ultrasonic Vibration ◽  
High Speed ◽  
Patent Application ◽  
Entrapment Efficiency ◽  
Proof Of Concept ◽  
Research Institutions ◽  
Novel Approach ◽  
Sophisticated Equipment

Background: Probe sonication and High-speed homogenizer are comparatively costly equipment to fabricate the nanoparticles. Many academic and research institutions cannot afford the procurement and maintenance of such sophisticated equipment. In the present work, a newer idea is conceptualized, which can be adopted by the underprivileged research institutions to fabricate solid lipid nanoparticles (SLN) in the absence of sophisticated equipment. The current work describes the pilot-level trials of this novel approach. This study represents the preliminary proof-of-concept trials for which the Indian patent application (3508/MUM/2015) is filed. Method: A frugal piece of equipment was made using a 50 ml centrifuge tube with conical bottom and a piezoelectric mist maker or humidifier. SLNs were prepared by combining the quasi-emulsion solvent evaporation approach and ultrasonic vibration approach. A quasi-emulsion was composed by the dropwise mixing of the organic solvent containing drug & lipid with an aqueous solution containing surfactant under continuous ultrasonic vibration in the piezoelectric chamber. The size of the droplets was significantly reduced due to piezoelectric ultrasonic vibration. Under the provision of mild vacuum and heat generated by vibration, the organic solvent was evaporated, which leaves behind a suspension of SLN. In the present work, albendazole was selected as a model drug. Various trials with Compritol 888 ATO® and Precirol ATO 5® as a lipid carrier and Tween 80 and Poloxamer 188 as a surfactant were performed. Zeta potential of SLNs was improved by the addition of polyelectrolytes like K2SO4 and Na4P2O7. Result and Conclusion: The ratio of drug to lipid was optimized to 1:4 for the most favorable results. SLN with a minimum Z-average diameter of 98.59 nm, -21 mV zeta potential, and 34.064 % (SD 10.78, n=9) entrapment efficiency were developed using the Precirol ATO 5 ® as a lipid carrier. The proof of concept for this novel approach is established through the development of Albendazole SLNs. This approach must also be evaluated for the development of polymeric nanoparticles and vesicular formulations. The further sophistication of the frugal equipment may allow more control over the quality of SLN. This approach will enable underprivileged researchers to prepare Nanopharmaceuticals. Researchers and students of such institutions can focus on the application of SLN by resolving the constraint of sophisticated equipment with this novel approach. This novel approach should also be tried for polymeric and vesicular nanopharmaceuticals.

A Genetic Algorithm Based Procedure for Extracting Optimal Solutions From a Morphological Chart

2007 ◽  
Author(s):  
Santosh Tiwari ◽  
Joshua Summers ◽  
Georges Fadel
Keyword(s):  
Genetic Algorithm ◽  
Optimization Problem ◽  
Mathematical Representation ◽  
Optimal Solutions ◽  
Proof Of Concept ◽  
Optimization Framework ◽  
Mutation Operators ◽  
Novel Approach ◽  
Morphological Chart ◽  
Crossover And Mutation

A novel approach using a genetic algorithm is presented for extracting globally satisfycing (Pareto optimal) solutions from a morphological chart where the evaluation and combination of “means to sub-functions” is modeled as a combinatorial multi-objective optimization problem. A fast and robust genetic algorithm is developed to solve the resulting optimization problem. Customized crossover and mutation operators specifically tailored to solve the combinatorial optimization problem are discussed. A proof-of-concept simulation on a practical design problem is presented. The described genetic algorithm incorporates features to prevent redundant evaluation of identical solutions and a method for handling of the compatibility matrix (feasible/infeasible combinations) and addressing desirable/undesirable combinations. The proposed approach is limited by its reliance on the quantifiable metrics for evaluating the objectives and the existence of a mathematical representation of the combined solutions. The optimization framework is designed to be a scalable and flexible procedure which can be easily modified to accommodate a wide variety of design methods that are based on the morphological chart.

scholarly journals Engineered algae: A novel oxygen-generating system for effective treatment of hypoxic cancer

2020 ◽  
Vol 6 (21) ◽  
pp. eaba5996 ◽  
Author(s):  
Yue Qiao ◽  
Fei Yang ◽  
Tingting Xie ◽  
Zhen Du ◽  
Danni Zhong ◽  
...  
Keyword(s):  
Proof Of Concept ◽  
Tumor Cell Apoptosis ◽  
Cancer Management ◽  
Novel Approach ◽  
Hypoxic Environment ◽  
Sequential Combination ◽  
Hypoxic Tumor ◽  
Local Oxygen ◽  
Generating System

Microalgae, a naturally present unicellular microorganism, can undergo light photosynthesis and have been used in biofuels, nutrition, etc. Here, we report that engineered live microalgae can be delivered to hypoxic tumor regions to increase local oxygen levels and resensitize resistant cancer cells to both radio- and phototherapies. We demonstrate that the hypoxic environment in tumors is markedly improved by in situ–generated oxygen through microalgae-mediated photosynthesis, resulting in notably radiotherapeutic efficacy. Furthermore, the chlorophyll from microalgae produces reactive oxygen species during laser irradiation, further augmenting the photosensitizing effect and enhancing tumor cell apoptosis. Thus, the sequential combination of oxygen-generating algae system with radio- and phototherapies has the potential to create an innovative treatment strategy to improve the outcome of cancer management. Together, our findings demonstrate a novel approach that leverages the products of photosynthesis for treatment of tumors and provide proof-of-concept evidence for future development of algae-enhanced radio- and photodynamic therapy.

scholarly journals Influence of the Active Screen Plasma Power during Afterglow Nitrocarburizing on the Surface Modification of AISI 316L

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1112
Author(s):  
Jan Böcker ◽  
Alexander Puth ◽  
Anke Dalke ◽  
Jürgen Röpcke ◽  
Jean-Pierre H. van Helden ◽  
...  
Keyword(s):  
Surface Modification ◽  
Surface Hardness ◽  
Additional Parameter ◽  
Gas Composition ◽  
Aisi 316L ◽  
Bias Power ◽  
Process Gas ◽  
316L Steel ◽  
Plasma Nitrocarburizing ◽  
Active Screen

Active screen plasma nitrocarburizing (ASPNC) increases the surface hardness and lifetime of austenitic stainless steel without deteriorating its corrosion resistance. Using an active screen made of carbon opens up new technological possibilities that have not been exploited to date. In this study, the effect of screen power variation without bias application on resulting concentrations of process gas species and surface modification of AISI 316L steel was studied. The concentrations of gas species (e.g., HCN, NH3, CH4, C2H2) were measured as functions of the active screen power and the feed gas composition at constant temperature using in situ infrared laser absorption spectroscopy. At constant precursor gas composition, the decrease in active screen power led to a decrease in both the concentrations of the detected molecules and the diffusion depths of nitrogen and carbon. Depending on the gas mixture, a threshold of the active screen power was found above which no changes in the expanded austenite layer thickness were measured. The use of a heating independent of the screen power offers an additional parameter for optimizing the ASPNC process in addition to changes in the feed gas composition and the bias power. In this way, an advanced process control can be established.

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