(Q)SAR Modelling of Nanomaterial Toxicity - A Critical Review

There is an increasing recognition that nanomaterials pose a risk to human health, and that the novel engineered nanomaterials (ENMs) in the nanotechnology industry and their increasing industrial usage poses the most immediate problem for hazard assessment, as many of them remain untested. The large number of materials and their variants (different sizes and coatings for instance) that require testing and ethical pressure towards non-animal testing means that expensive animal bioassay is precluded, and the use of (quantitative) structure activity relationships ((Q)SAR) models as an alternative source of hazard information should be explored. (Q)SAR modelling can be applied to fill the critical knowledge gaps by making the best use of existing data, prioritize physicochemical parameters driving toxicity, and provide practical solutions to the risk assessment problems caused by the diversity of ENMs. This paper covers the core components required for successful application of (Q)SAR technologies to ENMs toxicity prediction, and summarizes the published nano-(Q)SAR studies and outlines the challenges ahead for nano-(Q)SAR modelling. It provides a critical review of (1) the present status of the availability of ENMs characterization/toxicity data, (2) the characterization of nanostructures that meets the need of (Q)SAR analysis, (3) the summary of published nano-(Q)SAR studies and their limitations, (4) the in silico tools for (Q)SAR screening of nanotoxicity and (5) the prospective directions for the development of nano-(Q)SAR models

Fundamental Study of Photoluminescence-Shape Relationship of Fluorescent Nanodiamonds using Machine Learning Assisted Correlative Transmission Electron Microscopy and Photoluminescence Microscopy Method

Luminescent nanoparticles have shown wide applications ranging from lighting, display, sensors, and biomedical diagnostics and imaging. Among these, fluorescent nanodiamonds (FNDs) containing nitrogen-vacancy (NV) color centers are posed as emerging materials particularly in biomedical and biological imaging applications due to their room-temperature emission, excellent photo- and chemical- stability, high bio-compatibility, and versatile functionalization potentials. The shape variation of nanoparticles has a decisive influence on their fluorescence. However, current relative studies are limited by the lack of reliable statistical analysis of nanoparticle shape and the difficulty of achieving a precise correlation between shape/structure and optical measurements of large numbers of individual nanoparticles. Therefore, new methods are urgently needed to overcome these challenges to assist in nanoparticle synthesis control and fluorescence performance optimization. In this thesis a new correlative TEM and photoluminescence (PL) microscopy (TEMPL) method has been developed that combines the measurements of the optical properties and the materials structure at the exact same particle and sample area, so that accurate correlation can be established to statistically study the FND morphology/structure and PL properties, at the single nanoparticle level. Moreover, machine learning based methods have been developed for categorizing the 2D and 3D shapes of a large number of nanoparticles generated in TEMPL method. This ML-assisted TEMPL method has been applied to understand the PL correlation with the size and shape of FNDs at the single particle level. In this thesis, a strong correlation between particle morphology and NV fluorescence in FND particles has been revealed: thin, flake-like particles produce enhanced fluorescence. The robustness of this trend is proven in FND with different surface oxidation treatments. This finding offers guidance for fluorescence-optimized sensing applications of FND, by controlling the shape of the particles in fabrication. Overall the TEMPL methodology developed in the thesis provides a versatile and general way to study the shape and fluorescence relationship of various nanoparticles and opens up the possibility of correlation methods between other characterisation techniques

Towards a review of the EC Recommendation for a definition of the term "nanomaterial"; Part 1: Compilation of information concerning the experience with the definition

In October 2011 the European Commission (EC) published a Recommendation on the definition of nanomaterial (2011/696/EU). The purpose of this definition is to enable determination when a material should be considered a nanomaterial for regulatory purposes in the European Union. In view of the upcoming review of the current EC Definition of the term 'nanomaterial' and noting the need expressed by the EC Environment Directorate General and other Commission services for a set of scientifically sound reports as the basis for this review, the EC Joint Research Centre (JRC) prepares three consecutive reports, of which this is the first. This Report 1 compiles information concerning the experience with the definition regarding scientific-technical issues that should be considered when reviewing the current EC definition of nanomaterial. Based on this report and the feedback received, JRC will write a second, follow-up report. In this Report 2 the JRC will provide a detailed assessment of the scientific-technical issues compiled in Report 1, in relation to the objective of reviewing the current EC nanomaterial definition.JRC.I.4-Nanobioscience

Vision-based techniques for automatic marine plankton classification

Plankton are an important component of life on Earth. Since the 19th century, scientists have attempted to quantify species distributions using many techniques, such as direct counting, sizing, and classification with microscopes. Since then, extraordinary work has been performed regarding the development of plankton imaging systems, producing a massive backlog of images that await classification. Automatic image processing and classification approaches are opening new avenues for avoiding time-consuming manual procedures. While some algorithms have been adapted from many other applications for use with plankton, other exciting techniques have been developed exclusively for this issue. Achieving higher accuracy than that of human taxonomists is not yet possible, but an expeditious analysis is essential for discovering the world beyond plankton. Recent studies have shown the imminent development of real-time, in situ plankton image classification systems, which have only been slowed down by the complex implementations of algorithms on low-power processing hardware. This article compiles the techniques that have been proposed for classifying marine plankton, focusing on automatic methods that utilize image processing, from the beginnings of this field to the present day.Funding for open access charge: Universidad de Málaga / CBUA. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The authors wish to thank Alonso Hernández-Guerra for his frm support in the development of oceanographic technology. Special thanks to Laia Armengol for her help in the domain of plankton. This study has been funded by Feder of the UE through the RES-COAST Mac-Interreg pro ject (MAC2/3.5b/314). We also acknowledge the European Union projects SUMMER (Grant Agreement 817806) and TRIATLAS (Grant Agreement 817578) from the Horizon 2020 Research and Innovation Programme and the Ministry of Science from the Spanish Government through the Project DESAFÍO (PID2020-118118RB-I00)

The ecotoxicology of carbon nanotubes in the marine environment

With their high aspect ratio, strength, light weight and electrical conductivity single-walled carbon nanotubes (SWCNTs) provide properties of great interest to industry, and, consequently, are finding use in an ever increasing number of products and applications, which will eventually lead to their appearance in the environment. The toxicity of SWCNT, however, is controversial, mainly because of the inconsistency of results, owing to a lack of understanding of the behaviour of SWCNTs in environmental media. The present study explored the ecotoxicology of engineered SWCNTs and their interacton with other contaminants as well as their potential for trophic transfer. A series of co-contaminant experiments was performed to understand the interaction of SWCNTs with dissolved metals at low-level and non-toxic concentrations of both. The results showed that any nano-scale effects were negated by the tendency of uncoated SWCNTs to agglomerate in seawater. However, SWCNTs, in combination with natural organic matter (NOM), remained suspended for long enough to become available to filter-feeding mussels. A potentiating toxicological effect was observed, expressed as DNA strand breaks obtained using the comet assay and oxidative stress, on divalent metals afforded by negatively charged SWCNT agglomerates in seawater at concentrations as low as 5μg L-1. This is supported by the observation that SWCNTs alone were only toxic at concentrations ≥100μg L-1 and that the SWCNT-induced DNA damage was correlated with oxidative stress only in the absence of metals The potential for trophic transfer was assessd using the green algae (Tetraselmis suecica). Light microscopical observations, confirmed by SEM and Raman spectroscopy, showed that SWCNTs adhered to the external algal cell walls and TEM results suggested internaization. A direct effect of SWCNT exposure on the algae was a significant decrease in chlorophyll a concentrations and cell viability. Algea fed to mussels in the presence of SWCNTs led to a signifiacntly increased pseudofaeces production, suggesting selective feeding. However, histological sections of the mussel digestive gland following exposure showed evidence of SWCNTs containing algal and toxicological tests signs of DNA dmage and oxidative stress. In conclusion, the observed SWCNT-algal interaction may facilitate trophic transfer of SWCNTs up the food chain with potential consequences for human health. If these laboratory experiments are confirmed in the natural environment, the present results will have implications for the understanding of the role of carbon nanotubes in environmental metal dynamics, toxicology, and consequently, regulatory requirements

Mechanical and Thermal Properties of PLA composites Reinforced with Carbonized Lignin and Organically Modified Montmorillonite.

학위논문 (석사)-- 서울대학교 대학원 : 농업생명과학대학 바이오시스템.소재학부(바이오소재공학전공), 2019. 2. 박종신.본 연구에서는 바이오 플라스틱 중 하나인 폴리락타이드(PLA)에 탄화한 리그닌 및 유기화 몬모릴로나이트를 입자 형태의 보강재로 이용하여 고분자 복합재료를 제조하고 그 특성을 평가하였다. 펄프 공정의 부산물로 얻어진 가루 형태의 크라프트 리그닌(Kraft Lignin) 파우더를 질소 기체 하의 높은 온도 조건에서 처리하여 탄화한 뒤 기계적인 분쇄를 통해 입자 형태의 보강재로 제조하였고, 이렇게 가공된 리그닌의 형태학적 변화를 FE-SEM 이미지를 통해 관찰하였다. 또한 탄화과정을 거치며 일어난 리그닌의 화학적 변화를 SEM-EDS와 FT-IR를 통해 정량 및 정성분석 하였다. 탄화한 리그닌 이외의 보강재로는 유기화제의 일종인 메틸디히드록시에틸 수소화 탈로우 암모늄(Methyl dihydroxyethyl hydrogenated tallow ammonium)으로 유기화한 몬모릴로나이트를 이용하였다. 모든 복합재료들은 혼련기를 이용한 용융 혼합과 가열 압착기를 이용한 용융 압착을 통해 필름 형태로 제조되었다. 폴리락타이드/유기화 몬모릴로나이트, 폴리락타이드/탄화한 리그닌 복합재료, 폴리락타이드/탄화한 리그닌/유기화 몬모릴로나이트 복합재료를 제조하여 XRD, TEM을 통해 평가하였다. 또한 인장강도 측정을 통해 복합재료의 기계적 특성과 TGA/DTG, DSC를 통해 복합재료의 열적 특성을 관찰하였다. 분석 결과를 통해 탄화한 리그닌과 유기화 몬모릴로나이트를 함께 사용한 복합재료의 물성이 가장 우수함을 확인하였다.In this study, polylactide(PLA), one kind of bioplastics, was reinforced with carbonized lignin and montmorillonite mineral clay particles. The prepared polymer composites were characterized. Kraft lignin powders, a major by-product of pulp manufacturing process, was carbonized at a high temperature and mechanically milled to yield particulate reinforcements. The processed lignin particles were morphologically studied with field emission scanning electron microscope(FE-SEM) images. Furthermore, chemical changes of the lignin powders occurred during the processes were characterized by energy dispersive x-ray spectroscopy(EDS) and infra red spectroscopy(FT-IR) both quantitatively and qualitatively. Organically modified montmorillonite particles by methyl dihydroxyethyl hydrogenated tallow ammonium, an organic modifier, was also used as reinforcements. All the composites were prepared via melt-compounding and melt-pressing techniques using a bench kneader and a hydraulic hot press. PLA/Carbonized Lignin, PLA/Organically modified montmorillonite, and PLA/Organically modified montmorillonite /Carbonized lignin composites were prepared and characterized with XRD, TEM. In addition, mechanical properties and thermal properties of the composites were studied by tensile testings, thermogravimetric analysis(TGA), differential scanning calorimetry(DSC). The results showed that the PLA composite reinforced with both particulate reinforcements has the finest properties overall.초록 i 목차 ii List of Tables v List of Figures vi 1. 서 론 1 2. 문헌연구 4 2.1 고분자 복합재료 4 2.1.1 고분자 매트릭스 5 2.1.1.1 바이오 플라스틱 7 2.1.1.2 폴리락타이드 7 2.1.2 보강재 10 2.1.2.1 리그닌 12 2.1.2.2 몬모릴로나이트 14 2.2 고분자 복합재료의 제조 19 2.2.1 고분자 복합재료의 제조 방법 19 2.2.2 고분자 복합재료의 물성이 영향을 미치는 요인 20 3. 재료 및 방법 21 3.1 재료 및 시약 21 3.2 리그닌의 탄화와 분쇄 21 3.2.1 리그닌 탄화 21 3.2.2 탄화한 리그닌의 분쇄 22 3.3 복합재료의 제조 22 3.4 시험 분석법 27 3.4.1 탄화한 리그닌의 분석 27 3.4.2 PLA 복합재료 분석 28 4. 결과 및 고찰 31 4.1 탄화 및 분쇄한 리그닌의 평가 31 4.1.1 주사전자현미경과 에너지 분산형 분광분석 31 4.1.2 적외선 분광분석 35 4.1.3 라만 분광분석 37 4.1.4 분산도 변화 관찰 39 4.2 제조한 복합재료의 평가 41 4.2.1 X선 회절 분석 41 4.2.2 투과전자현미경 44 4.3 복합재료의 기계적 특성 48 4.4 복합재료의 열적 특성 56 4.4.1 열 중량 분석 56 4.4.2 시차주사열량계 63 5. 결론 69 참고문헌 71 Abstract 80Maste

Titanium Dioxide, NM-100, NM-101, NM-102, NM-103, NM-104, NM-105: Characterisation and Physico-Chemical Properties

The European Commission's Joint Research Centre (JRC) provides scientific support to European Union policy including nanotechnology. Within this context, the JRC launched, in February 2011, a repository for Representative Test Materials (RTMs), based on preparatory work started in 2008. It supports both EU and international research projects, and especially the OECD Working Party on Manufactured Nanomaterials (WPMN). The WPMN leads an exploratory testing programme "Testing a Representative set of Manufactured Nanomaterials" for the development and collection of data on characterisation, toxicological and ecotoxicological properties, as well as risk assessment and safety evaluation of nanomaterials. The purpose is to understand the applicability of the OECD Test Guidelines for the testing of nanomaterials as well as end-points relevant for such materials. The Repository responds to a need for nanosafety research purposes: availability of nanomaterial from a single production batch to enhance the comparability of results between different research laboratories and projects. The availability of representative nanomaterials to the international scientific community furthermore enhances and enables development of safe materials and products. The present report presents the physico-chemical characterisation of the Titanium dioxide series from the JRC repository: NM-100, NM-101, NM-102, NM-103, NM-104 and NM-105. NM-105 was selected as principal material for the OECD test programme "Testing a representative set of manufactured nanomaterials". NM-100 is included in the series as a bulk comparator. Each of these NMs originates from one batch of commercially manufactured TiO2. The TiO2 NMs may be used as representative material in the measurement and testing with regard to hazard identification, risk and exposure assessment studies. The results for more than 15 endpoints are addressed in the present report, including physico-chemical properties, such as size and size distribution, crystallite size and electron microscopy images. Sample and test item preparation procedures are addressed. The results are based on studies by several European laboratories participating to the NANOGENOTOX Joint Action, as well as by the JRC.JRC.I.4-Nanobioscience

Environmental Emissions

Today, the issue of environmental emissions is more important than ever before. Air pollution with particulates, soot, carbon, aerosols, heavy metals, and so on is causing adverse effects on human health as well as the environment. This book presents new research and findings related to environmental emissions, pollution, and future sustainability. Written by experts in the field, chapters cover such topics as health effects, emission monitoring and mitigation, and emission composition and measurement

Synthesis and characterization of cellulose nanofibre for electrically conductive paper

Submitted to School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa, June 2017There is huge drive to identify sustainable, renewable, and environmentally friendly raw materials and right technologies to make or use them. These technologies should be applied in place of the conventional non-sustainable and nonenvironmentally friendly currently used materials. Nanotechnology involves the use of materials that have at least one side with dimension 10-9 m. There is considerable effort directed at the much abundant forest product such as cellulose which can be processed into cellulose nanofibrillated fibres (CNF) and cellulose nanocrystals (CNC). This study involved the synthesis and testing of an electrical conductive cellulose nanofibre made from microcrystalline eucalyptus grandis pulp. In this project, microcrystalline cellulose (MFC) from wood pulp was mechanically fibrillated using a Pilot Refiner to develop microfibrils. The microfibrilated pulp was oxidised with a mixture of 2,2,6,6-tetramethylpyradine-1-oxyl (TEMPO), sodium bromide (NaBr) and sodium hypochlorite (NaOCl) to produce CNF . The CNF was washed, sonicated and dried to produce translucent sheets. The oxidation process was able to achieve both CNF and CNC from wood pulp which was verified and characterized by Techpap, SEM, TEM, FTIR, Hounsfield Tensile Tester and Multimeter. The Techpap instrument indicated that the starting raw unfibrilated and mechanical fibrillated pulp fibre widths were 3.18 and 3.07 microns respectively. After oxidation process the FTIR Spectra produced an absorbance peak at approximately 1720 to 1740 cm-1 wavenumbers that is characteristic of the aldehyde carbonyl stretch which was not present on the unoxidised pulp. The average tensile strength of the paper strips were determined to be 4.51kN/m using the standard procedure of the experiment. From the TEM images it was observed that the CNF and CNC had dimensions ranging from 1.4nm to 594nm from pulp. The SEM images showed that on drying the CNF and CNC repolymerised into nanogel. The resistivity of the control CNF was in the infinity range. When the CNF was treated with the reduced Graphene Oxide (GO), the resistivity was determined to be 4400 Ω.m. This resistivity translates to an electrical conductivity of 2.27x10-4 Ω-1.m-1 for a length of a paper strip that was 5mm long. The conductivity of the CNF material was significantly improved and fell within the range of semi-conductive materials. The overall research showed that the synthesized cellulose nanofibre hold a semi-conductor behavior, which add value information in the explored research area.XL201

Sustainable Pavement Engineering and Road Materials

In a similar way to many other engineering fields, the road pavement industry strongly affects the critical issues of our generation, including climate change, pollutant emission, the exploitation of natural resources and economic crises. For this reason, technicians and researchers are searching ravenously for sustainable solutions to implement in current road construction systems with the following goals: To reduce the consumption of energy and virgin materials; To run environmentally and economically friendly maintenance; To recycle waste from different industrial processes; To decrease the noise, the pollution and the heat generated by traffic, particularly in urban contexts. This Special Issue aims to collect high-quality studies that combine the aforementioned solutions, including works pertaining to: The hot, warm, and cold recycling of reclaimed asphalt pavement; Marginal materials for asphalt pavements; Innovative sustainable materials; Durability and environmental aspects; Structure performance, modeling and design; Advanced trends in rehabilitation and preservation; Surface characteristics and road safety; Management system/life cycle analysis; Urban heat island mitigation; Energy harvesting