Search

Your search keyword '"Tomczak, Nikodem"' showing total 239 results
Start Over Author "Tomczak, Nikodem"
239 results on '"Tomczak, Nikodem"'

1. Artificial intelligence moral agent as Adam Smith's impartial spectator

Author

Tomczak, Nikodem

Subjects
Economics - General Economics, Computer Science - Artificial Intelligence
Abstract

Adam Smith developed a version of moral philosophy where better decisions are made by interrogating an impartial spectator within us. We discuss the possibility of using an external non-human-based substitute tool that would augment our internal mental processes and play the role of the impartial spectator. Such tool would have more knowledge about the world, be more impartial, and would provide a more encompassing perspective on moral assessment.

Published
2023

6. Quantifying surface wetting properties using droplet probe AFM

Author

Daniel, Dan, Florida, Yunita, Lay, Chee Leng, Koh, Xue Qi, Sng, Anqi, and Tomczak, Nikodem

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Fluid Dynamics
Abstract

Surface wettability has a huge influence on its functional properties. For example, to minimize smudging, surfaces should be able to repel oil droplets. To quantify surface wettability, the most common approach is to measure the contact angles of a liquid droplet on the surface. While well-established and relatively easy to perform, contact angle measurements are crude and imprecise; moreover, they cannot spatially resolve surface heterogeneities that can contribute to surface fouling. To address these shortcomings, we report on using an Atomic Force Microscopy (AFM) technique to quantitatively measure the interaction forces between a micro-droplet and a surface with piconewton force resolution. We show how our technique can be used to spatially map topographical and chemical heterogeneities with micron resolution.

Published
2020

7. Mapping micron-scale wetting properties of superhydrophobic surfaces

Author

Daniel, Dan, Lay, Chee Leng, Sng, Anqi, Lee, Corryl Jing Jun, Neo, Darren Chi Jin, Ling, Xing Yi, and Tomczak, Nikodem

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Applied Physics, Physics - Fluid Dynamics
Abstract

There is a huge interest in developing super-repellent surfaces for anti-fouling and heat transfer applications. To characterize the wetting properties of such surfaces, the most common approach is to place a millimetric-sized droplet and measure its contact angles. The adhesion and friction forces can then be indirectly inferred from the Furmidge's relation. While easy to implement, contact angle measurements are semi-quantitative and cannot resolve wetting variations on a surface. Here, we attach a micrometric-sized droplet to an Atomic Force Microscope cantilever to directly measure adhesion and friction forces with nanonewton force resolutions. We spatially map the micron-scale wetting properties of superhydrophobic surfaces and observe the time-resolved pinning-depinning dynamics as a droplet detaches from or moves across the surface.

Published
2019
Full Text
View/download PDF

8. Machine learning and behavioral economics for personalized choice architecture

Author

Hrnjic, Emir and Tomczak, Nikodem

Subjects
Economics - General Economics, Computer Science - Machine Learning
Abstract

Behavioral economics changed the way we think about market participants and revolutionized policy-making by introducing the concept of choice architecture. However, even though effective on the level of a population, interventions from behavioral economics, nudges, are often characterized by weak generalisation as they struggle on the level of individuals. Recent developments in data science, artificial intelligence (AI) and machine learning (ML) have shown ability to alleviate some of the problems of weak generalisation by providing tools and methods that result in models with stronger predictive power. This paper aims to describe how ML and AI can work with behavioral economics to support and augment decision-making and inform policy decisions by designing personalized interventions, assuming that enough personalized traits and psychological variables can be sampled.

Published
2019

9. Hydration lubrication of polyzwitterionic brushes leads to nearly friction- and adhesion-free droplet motion

Author

Daniel, Dan, Chia, Alfred Yu Ting, Moh, Lionel Chuan Hui, Liu, Rongrong, Koh, Xue Qi, Zhang, Xing, and Tomczak, Nikodem

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Fluid Dynamics
Abstract

Recently, there has been much progress in the design and application of oil-repellent superoleophobic surfaces. Polyzwitterionic brush surfaces are of particular interest, because of their ability to repel oil under water, even in the absence of micro-/nano-structures. The origin of this underwater superoleophobicity is attributed to the presence of a stable water film beneath the oil droplet, but this had not been demonstrated experimentally. Here, using optical interferometric techniques, we show that an oil droplet effectively hydroplanes over a water film, whose thickness is between one hundred and hundreds of nanometres. In addition, using a custom-built Droplet Force Apparatus, we measured the friction and adhesion forces to be in the nN range for millimetric-sized droplets. These forces are much lower than for other classes of well-known liquid-repellent surfaces, including the lotus-effect and lubricant-infused surfaces, where the typical force is on the order of $\mu$N

Published
2019

10. Bio‐Polyethylene and Polyethylene Biocomposites: An Alternative Towards a Sustainable Future

Author

Debbie, Soo Xiang Yun, primary, Muiruri, Joseph Kinyanjui, additional, Wu, Wen‐Ya, additional, Yeo, Jayven Chee Chuan, additional, Wang, Suxi, additional, Tomczak, Nikodem, additional, Thitsartarn, Warintorn, additional, Tan, Beng Hoon, additional, Wang, Pei, additional, Wei, Fengxia, additional, Suwardi, Ady, additional, Xu, Jianwei, additional, Loh, Xian Jun, additional, Yan, Qingyu, additional, and Zhu, Qiang, additional

Published
2024
Full Text
View/download PDF

11. Bio‐Polyethylene and Polyethylene Biocomposites: An Alternative toward a Sustainable Future.

Author

Soo, Xiang Yun Debbie, Muiruri, Joseph Kinyanjui, Wu, Wen‐Ya, Yeo, Jayven Chee Chuan, Wang, Suxi, Tomczak, Nikodem, Thitsartarn, Warintorn, Tan, Beng Hoon, Wang, Pei, Wei, Fengxia, Suwardi, Ady, Xu, Jianwei, Loh, Xian Jun, Yan, Qingyu, and Zhu, Qiang

Subjects
SUSTAINABILITY, AGRICULTURAL wastes, FILLER materials, YOUNG'S modulus, WASTE management, BIODEGRADABLE plastics
Abstract

Polyethylene (PE), a highly prevalent non‐biodegradable polymer in the field of plastics, presents a waste management issue. To alleviate this issue, bio‐based PE (bio‐PE), derived from renewable resources like corn and sugarcane, offers an environmentally friendly alternative. This review discusses various production methods of bio‐PE, including fermentation, gasification, and catalytic conversion of biomass. Interestingly, the bio‐PE production volumes and market are expanding due to the growing environmental concerns and regulatory pressures. Additionally, the production of PE and bio‐PE biocomposites using agricultural waste as filler materials, highlights the growing demand for sustainable alternatives to conventional plastics. According to previous studies, addition of ≈50% defibrillated corn and abaca fibers into bio‐PE matrix and a compatibilizer, results in the highest Young's modulus of 4.61 and 5.81 GPa, respectively. These biocomposites have potential applications in automotive, building construction, and furniture industries. Moreover, the advancement made in abiotic and biotic degradation of PE and PE biocomposites is elucidated to address their environmental impacts. Finally, the paper concludes with insights into the opportunities, challenges, and future perspectives in the sustainable production and utilization of PE and bio‐PE biocomposites. In summary, production of PE and bio‐PE biocomposites can contribute to a cleaner and sustainable future. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

12. Hydrolytic degradation and biodegradation of polylactic acid electrospun fibers

Author

Debbie Soo, Xiang Yun, primary, Jia, Linran, additional, Lim, Qi Feng, additional, Chua, Ming Hui, additional, Wang, Suxi, additional, Hui, Hui Kim, additional, Min Regine, See Jia, additional, Chen, Yunjie, additional, Li, Jiuwei, additional, Wei, Fengxia, additional, Tomczak, Nikodem, additional, Kong, Junhua, additional, Loh, Xian Jun, additional, Fei, Xunchang, additional, and Zhu, Qiang, additional

Published
2024
Full Text
View/download PDF

13. Core‐Shell Micro‐ and Nano‐Structures for The Modification of Light‐Surface Interactions

Author

Yeo, Reuben J., primary, Yeo, Jayven C. C., additional, Yu Tan, Sze, additional, Sng, Anqi, additional, Tomczak, Nikodem, additional, Muiruri, Joseph Kinyanjui, additional, Wang, Suxi, additional, Wang, Pei, additional, Thitsartarn, Warintorn, additional, Wang, Fuke, additional, Ye, Enyi, additional, Li, Zibiao, additional, Xu, Jianwei, additional, Loh, Xian Jun, additional, and Zhu, Qiang, additional

Published
2023
Full Text
View/download PDF

14. Core‐Shell Micro‐ and Nano‐Structures for The Modification of Light‐Surface Interactions.

Author

Yeo, Reuben J., Yeo, Jayven C. C., Yu Tan, Sze, Sng, Anqi, Tomczak, Nikodem, Muiruri, Joseph Kinyanjui, Wang, Suxi, Wang, Pei, Thitsartarn, Warintorn, Wang, Fuke, Ye, Enyi, Li, Zibiao, Xu, Jianwei, Loh, Xian Jun, and Zhu, Qiang

Subjects
CLEAN energy, CLIMATE change, OPTICAL properties, ENERGY harvesting, OPTICAL materials, SOLAR spectra
Abstract

Controlling how a material interacts with light is key to optimizing its optical properties to fit a desired function or application. The most straightforward approach is to chemically or physically modify the surface exposed to incident light. An effective method of surface modification is based on the addition of core‐shell structures at the surface. Of particular importance to many technological applications are core‐shell structures with dimensions comparable to the wavelengths of light extending from the UV up to the near‐IR region of the electromagnetic spectrum, which coincides with the major part of the solar spectrum. Surface modification approaches to tailor the optical properties of materials in this range of wavelengths are increasingly relevant in the context of materials and devices used in sustainable energy applications, such as solar cells and heat‐reflective paints. These materials are useful to mitigate the current energy and climate crises by allowing for enhanced energy harvesting and improved thermal management, respectively. Here, recent progress in the fabrication and application of core‐shell micro‐/nano‐structures for the modification of light interaction with surfaces is highlighted. Some limitations and future directions for the design of core‐shell materials are also discussed. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

16. AFM manipulation of EGaIn microdroplets to generate controlled, on-demand contacts on molecular self-assembled monolayers

Author

Soh, Eugene Jia Hao, primary, Astier, Hippolyte P.A.G., additional, Daniel, Dan, additional, Chua, Jia Qing Isaiah, additional, Miserez, Ali, additional, Jia, Zian, additional, Li, Ling, additional, O' Shea, Sean J., additional, Bhaskaran, Harish, additional, Tomczak, Nikodem, additional, and Nijhuis, Christian A., additional

Published
2022
Full Text
View/download PDF

34. Origin of Underwater Oil‐Repellence in Polyelectrolyte Brush Surfaces.

Author

Daniel, Dan, Goh, Shermin Simin, Truong, Tran Ngoc Bao, Koh, Xue Qi, and Tomczak, Nikodem

Subjects
ATOMIC force microscopy, MOIETIES (Chemistry), POLYELECTROLYTES
Abstract

When submerged under water, polyelectrolyte brush surfaces become highly oil‐repellent. This is due to the ability of the charged moieties on the polymer backbone to retain strong hydration shells. Despite their technological relevance, there is no rational design principle for optimizing the oil‐repellent performance of hydrophilic polyelectrolyte brushes. Using droplet probe atomic force microscopy, the interaction forces between an oil droplet and different polyelectrolyte brushes are measured. It is shown that surfaces are most repellent when there are repulsive electric double‐layer forces that can stabilize a continuous water film beneath the oil droplet. Once a stable hydration layer forms, the oil‐repellent performance is not affected by the polymer brush characteristics, such as its thickness and swelling ratio. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

38. Segment dynamics in thin polystyrene films probed by single-molecule optics

Author

Tomczak, Nikodem, Vallee, Renaud A. L., Erick M. H. P. van Dijk, Kuipers, Laurens, and Niek F. van Hulst ; Vancso, G. Julius

Subjects
Molecular structure -- Research, Polymers -- Research, Chemistry
Abstract

The effects of thin film in a glassy polymer system at temperatures far below bulk of glass transition (Tg) are investigated and the use of single-molecule fluorescence lifetime is discussed. The results indicate that a modified segment scale dynamics is found, when the polymer is confined into films with thickness below 50-60 nm.

Published
2004

41. Silica shelled and block copolymer encapsulated red-emissive AIE nanoparticles with 50% quantum yield for two-photon excited vascular imaging

Author

Geng, Junlong, Goh, Chiching, Qin, Wei, Liu, Rongrong, Tomczak, Nikodem, Ng, Lai Guan, Tang, Benzhong, Liu, Bin, Geng, Junlong, Goh, Chiching, Qin, Wei, Liu, Rongrong, Tomczak, Nikodem, Ng, Lai Guan, Tang, Benzhong, and Liu, Bin

Abstract

A polymer and silica co-protection strategy has been developed to encapsulate organic fluorogens with aggregation-induced emission and charge transfer characteristics into small nanoparticles (NPs). The co-pretected NPs show bright red fluorescence (50% quantum yield) with a large two-photon action cross-section (450 GM at 840 nm), which have been sucessfully used for two-photon fluorescence imaging of vasculature of the mouse tibial muscle.

Published
2015

42. Enabling biomedical research with designer quantum dots

Author

Tomczak, Nikodem, Jańczewski, Dominik, Dorokhin, Denis, Han, Ming-Yong, Vancso, G. Julius, Navarro, Melba, Planell, Josep A., Faculty of Science and Technology, and Materials Science and Technology of Polymers

Subjects
Materials science, Quantum dot, Aptamer, Bioactive molecules, technology, industry, and agriculture, Nanomedicine, Surface modification, Surface chemical, Nanotechnology, Biocompatible material, equipment and supplies, 22/4 OA procedure, Preclinical imaging
Abstract

Quantum Dots (QDs) are a new class of semiconductor nanoparticulate luminophores, which are actively researched for novel applications in biology and nanomedicine. In this review, the recent progress in the design and applications of QD labels for in vitro and in vivo imaging of cells is presented. Surface chemical engineering of hydrophobic QDs is required to render them water soluble and biocompatible. Further surface modification and attachment of bioactive molecules to the surface of QDs, such as peptides, aptamers, or antibodies are intensively explored for targeted imaging of living cells, and disease states in animals. Specially designed surface coatings can drastically decrease nonspecific interactions between QDs and cells, minimize degradation of QDs under in vivo physiological conditions, reduce the cytotoxicity of QDs, and prolong circulation lifetimes in animals. New generations of QD probes are also promising for imaging cellular processes at the single-molecule level. Ultimately, QDs as components of complex therapeutic nanosystems are poised to contribute significantly to the field of personalized medicine.

Published
2012

44. Regenerative Medicine: Conjugated Polymer Nanodots as Ultrastable Long-Term Trackers to Understand Mesenchymal Stem Cell Therapy in Skin Regeneration (Adv. Funct. Mater. 27/2015)

Author

Jin, Guorui, primary, Mao, Duo, additional, Cai, Pingqiang, additional, Liu, Rongrong, additional, Tomczak, Nikodem, additional, Liu, Jie, additional, Chen, Xiaodong, additional, Kong, Deling, additional, Ding, Dan, additional, Liu, Bin, additional, and Li, Kai, additional

Published
2015
Full Text
View/download PDF

48. Precise and Long-Term Tracking of Adipose-Derived Stem Cells and Their Regenerative Capacity via Superb Bright and Stable Organic Nanodots

Author

Ding, Dan, Mao, Duo, Li, Kai, Wang, Xiaomin, Qin, Wei, Liu, Rongrong, Chiam, David Shunzhong, Tomczak, Nikodem, Yang, Zhimou, Tang, Ben Zhong, Kong, Deling, Liu, Bin, Ding, Dan, Mao, Duo, Li, Kai, Wang, Xiaomin, Qin, Wei, Liu, Rongrong, Chiam, David Shunzhong, Tomczak, Nikodem, Yang, Zhimou, Tang, Ben Zhong, Kong, Deling, and Liu, Bin

Abstract

Monitoring and understanding long-term fate and regenerative therapy of administrated stem cells in vivo is of great importance. Herein we report organic nanodots with aggregation-induced emission characteristics (AIE dots) for long-term tracking of adipose-derived stem cells (ADSCs) and their regenerative capacity in living mice. The AIE dots possess high fluorescence (with a high quantum yield of 25 +/- 1%), excellent biological and photophysical stabilities, low in vivo toxicity, and superb retention in living ADSCs with negligible interference on their pluripotency and secretome. These AIE dots also exhibit superior in vitro cell tracking capability compared to the most popular commercial cell trackers, PKH26 and Qtracker 655. In vivo quantitative studies with bioluminescence and GFP labeling as the controls reveal that the AIE dots can precisely and quantitatively report the fate of ADSCs and their regenerative capacity for 42 days in an ischemic hind limb bearing mouse model.

Published
2014

49. Ultrabright organic dots with aggregation-induced emission characteristics for cell tracking

Author

Feng, Guangxue, Tay, Chor Yong, Chui, Qi Xiang, Liu, Rongrong, Tomczak, Nikodem, Liu, Jie, Tang, Ben Zhong, Leong, David Tai, Liu, Bin, Feng, Guangxue, Tay, Chor Yong, Chui, Qi Xiang, Liu, Rongrong, Tomczak, Nikodem, Liu, Jie, Tang, Ben Zhong, Leong, David Tai, and Liu, Bin

Abstract

Noninvasive fluorescence cell tracking provides critical information on the physiological displacement and translocation of actively migrating cells, which deepens our understanding of biomedical engineering, oncological research, stem cell transplantation and therapies. Non-viral fluorescent protein transfection based cell tracing has been widely used but with issues related to cell type-dependent expression, lagged readout, immunogenicity and mutagenesis. Alternative cell tracking methods are therefore desired to attain reliable, stable, and efficient labeling over a long time. In this work, we have successfully developed ultra-bright organic dots with aggregation-induced emission (AIE dots) and demonstrated their capabilities for cellular imaging and cell tracking. The AIE dots possess high fluorescence, super photostability, and excellent cellular retention and biocompatibility. As compared to commonly used pMAX-GFP plasmid labeling approach, the organic AIE dots showed excellent cell labeling on all tested human cell lines and superior tracing performance, which opens up new opportunities in the cell-based immunotherapies and other related biological researches. (C) 2014 Elsevier Ltd. All rights reserved.

Published
2014

Catalog

Books, media, physical & digital resources
See catalog results