Science.gov

Sample records for assess engineered nanoparticle

  1. Acellular assessments of engineered-manufactured nanoparticle biological surface reactivity

    EPA Science Inventory

    It is critical to assess the surface properties and reactivity of engineered-manufactured nanoparticles (NPs) as these will influence their interactions with biological systems, biokinetics and toxicity. We examined the physicochemical properties and surface reactivity of metal o...

  2. Microplastic Exposure Assessment in Aquatic Environments: Learning from Similarities and Differences to Engineered Nanoparticles.

    PubMed

    Hüffer, Thorsten; Praetorius, Antonia; Wagner, Stephan; von der Kammer, Frank; Hofmann, Thilo

    2017-03-07

    Microplastics (MPs) have been identified as contaminants of emerging concern in aquatic environments and research into their behavior and fate has been sharply increasing in recent years. Nevertheless, significant gaps remain in our understanding of several crucial aspects of MP exposure and risk assessment, including the quantification of emissions, dominant fate processes, types of analytical tools required for characterization and monitoring, and adequate laboratory protocols for analysis and hazard testing. This Feature aims at identifying transferrable knowledge and experience from engineered nanoparticle (ENP) exposure assessment. This is achieved by comparing ENP and MPs based on their similarities as particulate contaminants, whereas critically discussing specific differences. We also highlight the most pressing research priorities to support an efficient development of tools and methods for MPs environmental risk assessment.

  3. Fate assessment of engineered nanoparticles in solids dominated media - Current insights and the way forward.

    PubMed

    Peijnenburg, W; Praetorius, A; Scott-Fordsmand, J; Cornelis, G

    2016-11-01

    Exposure assessment of engineered nanoparticles (ENPs) in soil and sediment is severely hampered by a lack of understanding of the underlying processes and of the impact of matrix constituents on the fate of ENPs in natural systems, including porewater properties like pH, ionic strength, and presence of naturally occurring (nano)particles. Additional issues such as lack of proper methods for in-situ assessment of ENP speciation, ENP ageing, and agglomeration state, hinder proper exposure assessment. Let alone that the lack does not allow for development of predictive methods for endpoints like transformation and agglomeration potential. This paper discusses current approaches for fate assessment of ENPs in solids dominated media and addresses the most prominent knowledge gaps and how these may be addressed. It is concluded that the key issue to be dealt with, are the attachment and deposition processes that are characteristic for ENPs as opposed to equilibrium-driven partitioning processes of non-particulate organic and inorganic contaminants.

  4. Exploring the development of a decision support system (DSS) to prioritize engineered nanoparticles for risk assessment

    NASA Astrophysics Data System (ADS)

    Marvin, Hans J. P.; Bouwmeester, Hans; Bakker, Martine; Kroese, E. Dinant; van de Meent, Dik; Bourgeois, Francois; Lokers, Rob; van der Ham, Henk; Verhelst, Lieke

    2013-08-01

    Engineered nanoparticles (ENPs) have gained huge commercial interest because of their unique and size-related physicochemical properties. The diversity and complexity of ENPs is increasing with the introduction of next generation nanoparticles. The current approaches are not able to assess the safety of all types and applications of ENPs. Therefore, we are developing a decision support system (DSS) that helps to identify those ENPs and applications that should get priority in the risk assessment. This DSS smartly uses existing knowledge in publicly available databases. With the aid of vocabularies, knowledge rules and logic reasoning new knowledge will be derived. In this paper, the procedure for a DSS is described. Since this system is open by design, others can re-use and extend the DSS content, and newly developed DSS tools can be easily accommodated, which will make the DSS more effective over the years. Data of newly emerging studies will be used for the validation of the DSS. The results will benefit regulating authorities and scientists focussing on the development of inherently safe ENPs.

  5. Assessing the impact of engineered nanoparticles on wound healing using a novel in vitro bioassay

    PubMed Central

    Zhou, Enhua H; Watson, Christa; Pizzo, Richard; Cohen, Joel; Dang, Quynh; de Barros, Pedro Macul Ferreira; Park, Chan Young; Chen, Cheng; Brain, Joseph D; Butler, James P; Ruberti, Jeffrey W; Fredberg, Jeffrey J; Demokritout, Philip

    2015-01-01

    Aim As engineered nanoparticles (ENPs) increasingly enter consumer products, humans become increasingly exposed. The first line of defense against ENPs is the epithelium, the integrity of which can be compromised by wounds induced by trauma, infection, or surgery, but the implications of ENPs on wound healing are poorly understood. Materials & methods Herein, we developed an in vitro assay to assess the impact of ENPs on the wound healing of cells from human cornea. Results & discussion We show that industrially relevant ENPs impeded wound healing and cellular migration in a manner dependent on the composition, dose and size of the ENPs as well as cell type. CuO and ZnO ENPs impeded both viability and wound healing for both fibroblasts and epithelial cells. Carboxylated polystyrene ENPs retarded wound healing of corneal fibroblasts without affecting viability. Conclusion Our results highlight the impact of ENPs on cellular wound healing and provide useful tools for studying the physiological impact of ENPs. PMID:24823434

  6. Physicochemical comparison of commercially available metal oxide nanoparticles: implications for engineered nanoparticle toxicology and risk assessment

    EPA Science Inventory

    Accurate and affordable physicochemical characterization of commercial engineered nanomaterials is required for toxicology studies to ultimately determine nanomaterial: hazard identification; dose to response metric(s); and mechanism(s) of injury. A minimal physical and chemica...

  7. Assessing the Immunosafety of Engineered Nanoparticles with a Novel in Vitro Model Based on Human Primary Monocytes.

    PubMed

    Li, Yang; Italiani, Paola; Casals, Eudald; Valkenborg, Dirk; Mertens, Inge; Baggerman, Geert; Nelissen, Inge; Puntes, Victor F; Boraschi, Diana

    2016-10-13

    The possibility that nanomaterials could perturb the normal course of an inflammatory response is a key issue when assessing nanoimmunosafety. The alteration of the normal progress of an inflammatory response may have pathological consequences, since inflammation is a major defensive mechanism and its efficiency maintains the body's health. The immunosafety of engineered nanoparticles at nontoxic concentrations was investigated with the use of a human primary monocyte-based in vitro system, which reproduces in a simplified fashion the full course of the physiological inflammatory response, from initiation and development to resolution. The kinetics of expression and production of inflammatory and anti-inflammatory cytokines and the proteomic profiles were used for describing the inflammatory defensive response. We assessed the ability of gold and silver nanoparticles to trigger inflammation and to interfere with the course of an ongoing defensive reaction. While neither nanoparticle type was able to directly activate monocytes, silver nanoparticles could exacerbate the inflammatory response of monocytes but did not interfere with the resolution of the inflammatory reaction. These findings support the use of human primary monocyte-based in vitro assays for realistically investigating the effects of engineered nanoparticles on human innate immune responses, in order to predict the immunological risk of nanomaterials and implement safe nanoparticle-based applications.

  8. Critical assessment of models for transport of engineered nanoparticles in saturated porous media.

    PubMed

    Goldberg, Eli; Scheringer, Martin; Bucheli, Thomas D; Hungerbühler, Konrad

    2014-11-04

    To reliably assess the fate of engineered nanoparticles (ENP) in soil, it is important to understand the performance of models employed to predict vertical ENP transport. We assess the ability of seven routinely employed particle transport models (PTMs) to simulate hyperexponential (HE), nonmonotonic (NM), linearly decreasing (LD), and monotonically increasing (MI) retention profiles (RPs) and the corresponding breakthrough curves (BTCs) from soil column experiments with ENPs. Several important observations are noted. First, more complex PTMs do not necessarily perform better than simpler PTMs. To avoid applying overparameterized PTMs, multiple PTMs should be applied and the best model selected. Second, application of the selected models to simulate NM and MI profiles results in poor model performance. Third, the selected models can well-approximate LD profiles. However, because the models cannot explicitly generate LD retention, these models have low predictive power to simulate the behavior of ENPs that present LD profiles. Fourth, a term for blocking can often be accounted for by parameter variation in models that do not explicitly include a term for blocking. We recommend that model performance be analyzed for RPs and BTCs separately; simultaneous fitting to the RP and BTC should be performed only under conditions where sufficient parameter validation is possible to justify the selection of a particular model.

  9. Laboratory Assessment of the Mobility of Water-Dispersed Engineered Nanoparticles in a Red Soil (Ultisol)

    EPA Science Inventory

    Soils are major sinks of engineered nanoparticles (ENPs) as results of land applications of sewage sludge, accidental spills, or deliberate applications of ENPs (e.g., nano-pesticides). In this study, the transport behaviors of four widely used ENPs (titanium dioxide [TiO2], buck...

  10. Analytical characterization of engineered ZnO nanoparticles relevant for hazard assessment

    NASA Astrophysics Data System (ADS)

    Bragaru, Adina; Kusko, Mihaela; Vasile, Eugeniu; Simion, Monica; Danila, Mihai; Ignat, Teodora; Mihalache, Iuliana; Pascu, Razvan; Craciunoiu, Florea

    2013-01-01

    The optoelectronic properties of zinc oxide nanoparticles (ZnO-NPs) have determined development of novel applications in catalysis, paints, wave filters, UV detectors, transparent conductive films, solar cells, or sunscreens. While the immediate advantages of using nano-ZnO in glass panel coatings and filter screens for lamps, as protecting products against bleaching, have been demonstrated, the potential environmental effect of the engineered NPs and the associated products was not fully estimated; this issue being of utmost importance, as these materials will be supplied to the market in quantities of tons per year, equating to thousands of square meters. In this study, ZnO-NPs with commercial name Zincox™ have been subjected to a comprehensive characterization, relevant for hazard assessment, using complementary physico-chemical methods. Therefore, the morphological investigations have been corroborated with XRD pattern analyses and UV-Vis absorption related properties resulting an excellent correlation between the geometrical sizes revealed by microscopy (8.0-9.0 nm), and, respectively, the crystallite size (8.2-9.5 nm) and optical size (7.8 nm) calculated from the last two techniques' data. Furthermore, the hydrodynamic diameter of ZnO-NPs and stability of aqueous dispersions with different concentration of nanoparticles have been analyzed as function of significant solution parameters, like concentration, pH and solution ionic strength. The results suggest that solution chemistry exerts a strong influence on ZnO dissolution stability, the complete set of analyses providing useful information toward better control of dosage during biotoxicological tests.

  11. Non-Engineered Nanoparticles of C60

    PubMed Central

    Deguchi, Shigeru; Mukai, Sada-atsu; Sakaguchi, Hide; Nonomura, Yoshimune

    2013-01-01

    We discovered that rubbing bulk solids of C60 between fingertips generates nanoparticles including the ones smaller than 20 nm. Considering the difficulties usually associated with nanoparticle production by pulverisation, formation of nanoparticles by such a mundane method is unprecedented and noteworthy. We also found that nanoparticles of C60 could be generated from bulk solids incidentally without deliberate engineering of any sort. Our findings imply that there exist highly unusual human exposure routes to nanoparticles of C60, and elucidating formation mechanisms of nanoparticles is crucial in assessing their environmental impacts. PMID:23807024

  12. Laboratory assessment of the mobility of water-dispersed engineered nanoparticles in a red soil (Ultisol)

    NASA Astrophysics Data System (ADS)

    Wang, Dengjun; Su, Chunming; Zhang, Wei; Hao, Xiuzhen; Cang, Long; Wang, Yujun; Zhou, Dongmei

    2014-11-01

    Soils are major sinks of engineered nanoparticles (ENPs) as results of land applications of sewage sludge, accidental spills, or deliberate applications of ENPs (e.g., nano-pesticides). In this study, the transport behaviors of four widely used ENPs (i.e., titanium dioxide [TiO2], buckminsterfullerene [C60], single-walled carbon nanotube [SWNT], and elemental silver [Ag0]) were investigated in water-saturated columns packed with either a quartz sand, a red soil (Ultisol), or sand/soil mixtures with soil mass fraction (λ) from 0% to 100% at slightly acidic solution pH (4.0-5.0). The mobility of tested ENPs decreased significantly with increasing λ, which was attributed to increased surface area and/or retention sites imparted by iron oxides, clay minerals, and organic matter in the red soil. Breakthrough curves of all ENPs exhibited blocking effects (decreasing deposition rate over time) and were well-described using an unfavorable and favorable, two-site kinetic attachment model accounting for random sequential adsorption on the favorable site. Modeled maximum retention capacity and first-order attachment rate coefficient on the favorable site both increased linearly with increasing λ, suggesting that transport parameters of ENPs in natural soils may be accurately extrapolated from transport parameters in the sand/soil mixtures. In addition, the mobility of three negatively charged ENPs (C60, SWNT, and Ag0 NPs) was reversely correlated with their average hydrodynamic diameters, highlighting that the average hydrodynamic diameter of negatively charged ENPs is the dominant physicochemical characteristics controlling their mobility in the Ultisol.

  13. New insight into artifactual phenomena during in vitro toxicity assessment of engineered nanoparticles: study of TNF-α adsorption on alumina oxide nanoparticle.

    PubMed

    Pailleux, Mélanie; Boudard, Delphine; Pourchez, Jérémie; Forest, Valérie; Grosseau, Philippe; Cottier, Michèle

    2013-04-01

    Biomolecules can be adsorbed on nanoparticles (NPs) and degraded during in vitro toxicity assays. These artifactual phenomena could lead to misinterpretation of biological activity, such as false-negative results. To avoid possible underestimation of cytokine release after contact between NP and cells, we propose a methodology to account for these artifactual phenomena and lead to accurate measurements. We focused on the pro-inflammatory cytokine tumor necrosis factor TNF-α. We studied well-characterized boehmite engineered NP [aluminum oxide hydroxide, AlO(OH)]. The rate of TNF-α degradation and its adsorption (on boehmite and on the walls of wells) were determined in cell-free conditions by adding a known TNF-α concentration (1500 pg/ml) under various experimental conditions. After a 24-h incubation, we quantified that 7 wt.% of the initial TNF-α was degraded over time, 6 wt.% adsorbed on the walls of 96-well plates, and 13 wt.% adsorbed on the boehmite surface. Finally, boehmite NP were incubated with murine macrophages (RAW 264.7 cell line). The release of TNF-α was assessed for boehmite NP and the experimental data were corrected considering the artifactual phenomena, which accounted for about 20-30% of the total.

  14. Nanoparticle Superlattice Engineering with DNA

    NASA Astrophysics Data System (ADS)

    Macfarlane, Robert John

    developments in DNA-programmed nanoparticle assembly not covered in this thesis, as well as future challenges for this field. Supplementary information to support the conclusions of the thesis, as well as provide technical details on how these materials are synthesized, are provided in appendices at the end of the thesis. As a whole, this methodology presents a major advance towards nanoparticle superlattice engineering, as it effectively separates the identity of a particle core (and thereby its physical properties) from the variables that control its assembly, enabling the synthesis of designer nanoparticle-based materials.

  15. Nanoparticle Superlattice Engineering with DNA

    NASA Astrophysics Data System (ADS)

    Macfarlane, Robert J.; Lee, Byeongdu; Jones, Matthew R.; Harris, Nadine; Schatz, George C.; Mirkin, Chad A.

    2011-10-01

    A current limitation in nanoparticle superlattice engineering is that the identities of the particles being assembled often determine the structures that can be synthesized. Therefore, specific crystallographic symmetries or lattice parameters can only be achieved using specific nanoparticles as building blocks (and vice versa). We present six design rules that can be used to deliberately prepare nine distinct colloidal crystal structures, with control over lattice parameters on the 25- to 150-nanometer length scale. These design rules outline a strategy to independently adjust each of the relevant crystallographic parameters, including particle size (5 to 60 nanometers), periodicity, and interparticle distance. As such, this work represents an advance in synthesizing tailorable macroscale architectures comprising nanoscale materials in a predictable fashion.

  16. Toxicity of Engineered Nanoparticles in the Environment

    PubMed Central

    Maurer-Jones, Melissa A.; Gunsolus, Ian L.; Murphy, Catherine J.; Haynes, Christy L.

    2014-01-01

    While nanoparticles occur naturally in the environment and have been intentionally used for centuries, the production and use of engineered nanoparticles has seen a recent spike, which makes environmental release almost certain. Therefore, recent efforts to characterize the toxicity of engineered nanoparticles have focused on the environmental implications, including exploration of toxicity to organisms from wide-ranging parts of the ecosystem food webs. Herein, we summarize the current understanding of toxicity of engineered nanoparticles to representatives of various trophic levels, including bacteria, plants, and multicellular aquatic/terrestrial organisms, to highlight important challenges within the field of econanotoxicity, challenges that analytical chemists are expertly poised to address. PMID:23427995

  17. Limitations and relative utility of screening assays to assess engineered nanoparticle toxicity in a human cell line

    SciTech Connect

    Monteiro-Riviere, N.A.; Inman, A.O.; Zhang, L.W.

    2009-01-15

    Single-walled carbon nanotubes (SWCNT), fullerenes (C{sub 60}), carbon black (CB), nC{sub 60}, and quantum dots (QD) have been studied in vitro to determine their toxicity in a number of cell types. Here, we report that classical dye-based assays such as MTT and neutral red (NR) that determine cell viability produce invalid results with some NM (nanomaterials) due to NM/dye interactions and/or NM adsorption of the dye/dye products. In this study, human epidermal keratinocytes (HEK) were exposed in vitro to CB, SWCNT, C{sub 60}, nC{sub 60}, and QD to assess viability with calcein AM (CAM), Live/Dead (LD), NR, MTT, Celltiter 96 AQueous One (96 AQ), alamar Blue (aB), Celltiter-Blue (CTB), CytoTox One{sup TM} (CTO), and flow cytometry. In addition, trypan blue (TB) was quantitated by light microscopy. Assay linearity (R{sup 2} value) was determined with HEK plated at concentrations from 0 to 25,000 cells per well in 96-well plates. HEK were treated with serial dilutions of each NM for 24 h and assessed with each of the viability assays. TB, CAM and LD assays, which depend on direct staining of living and/or dead cells, were difficult to interpret due to physical interference of the NM with cells. Results of the dye-based assays varied a great deal, depending on the interactions of the dye/dye product with the carbon nanomaterials (CNM). Results show the optimal high throughput assay for use with carbon and noncarbon NM was 96 AQ. This study shows that, unlike small molecules, CNM interact with assay markers to cause variable results with classical toxicology assays and may not be suitable for assessing nanoparticle cytotoxicity. Therefore, more than one assay may be required when determining nanoparticle toxicity for risk assessment.

  18. Engineered nanoparticles for biomolecular imaging

    NASA Astrophysics Data System (ADS)

    Mahmoudi, Morteza; Serpooshan, Vahid; Laurent, Sophie

    2011-08-01

    In recent years, the production of nanoparticles (NPs) and exploration of their unusual properties have attracted the attention of physicists, chemists, biologists and engineers. Interest in NPs arises from the fact that the mechanical, chemical, electrical, optical, magnetic, electro-optical and magneto-optical properties of these particles are different from their bulk properties and depend on the particle size. There are numerous areas where nanoparticulate systems are of scientific and technological interest, particularly in biomedicine where the emergence of NPs with specific properties (e.g. magnetic and fluorescence) for contrast agents can lead to advancing the understanding of biological processes at the biomolecular level. This review will cover a full description of the physics of various imaging methods, including MRI, optical techniques, X-rays and CT. In addition, the effect of NPs on the improvement of the mentioned non-invasive imaging methods will be discussed together with their advantages and disadvantages. A detailed discussion will also be provided on the recent advances in imaging agents, such as fluorescent dye-doped silica NPs, quantum dots, gold- and engineered polymeric-NPs, superparamagnetic iron oxide NPs (SPIONs), and multimodal NPs (i.e. nanomaterials that are active in both MRI and optical methods), which are employed to overcome many of the limitations of conventional contrast agents (e.g. gadolinium).

  19. Pulmonary applications and toxicity of engineered nanoparticles.

    PubMed

    Card, Jeffrey W; Zeldin, Darryl C; Bonner, James C; Nestmann, Earle R

    2008-09-01

    Because of their unique physicochemical properties, engineered nanoparticles have the potential to significantly impact respiratory research and medicine by means of improving imaging capability and drug delivery, among other applications. These same properties, however, present potential safety concerns, and there is accumulating evidence to suggest that nanoparticles may exert adverse effects on pulmonary structure and function. The respiratory system is susceptible to injury resulting from inhalation of gases, aerosols, and particles, and also from systemic delivery of drugs, chemicals, and other compounds to the lungs via direct cardiac output to the pulmonary arteries. As such, it is a prime target for the possible toxic effects of engineered nanoparticles. The purpose of this article is to provide an overview of the potential usefulness of nanoparticles and nanotechnology in respiratory research and medicine and to highlight important issues and recent data pertaining to nanoparticle-related pulmonary toxicity.

  20. Engineered nanoparticles: Revisiting safety concerns in light of ethno medicine.

    PubMed

    Palkhiwala, Suhani; Bakshi, Sonal R

    2014-01-01

    The nanoparticles are a miracle invention of the century that has opened novel avenues of applications in various fields. The safety aspect of exposure to nanoparticles for humans, plants, animals, soil micro-flora, and ecosystem at large has been questioned. The safety concern can be addressed by laboratory studies to assess the actual risk and recommend exposure limits and related regulation. There is also a suggestion for considering the nanoparticle form of conventional compounds as a new chemical and subject it to safety assessment in line with the chemical regulatory agencies. In the light of the current scenario of popularity and safety concerns regarding nanoparticles, the use of ancient metal based forms like, Bhasma is revisited in the present article. The current approach of green synthesis of nanoparticles is compared with the Ayurveda Rasayana Shastra guidelines of Bhasma preparation and modern preparation of engineered nanoparticles. Since the benefits of nanotechnology are undeniable, and safety concerns are also not ungrounded, there is a pressing need to revisit the ways nanoparticles are manufactured, and to carry out safety assessment by the techniques specially adapted for this novel compound.

  1. Interfacial functionalization and engineering of nanoparticles

    NASA Astrophysics Data System (ADS)

    Song, Yang

    The intense research interest in nanoscience and nanotechnology is largely fueled by the unique properties of nanoscale materials. In this dissertation, the research efforts are focused on surface functionalization and interfacial engineering of functional nanoparticles in the preparation of patchy nanoparticles (e.g., Janus nanoparticles and Neapolitan nanoparticles) such that the nanoparticle structures and properties may be manipulated to an unprecedented level of sophistication. Experimentally, Janus nanoparticles were prepared by an interfacial engineering method where one hemisphere of the originally hydrophobic nanoparticles was replaced with hydrophilic ligands at the air|liquid or solid|liquid interface. The amphiphilic surface characters of the Janus nanoparticles were verified by contact angle measurements, as compared to those of the bulk-exchange counterparts where the two types of ligands were distributed rather homogeneously on the nanoparticle surface. In a further study, a mercapto derivative of diacetylene was used as the hydrophilic ligands to prepare Janus nanoparticles by using hydrophobic hexanethiolate-protected gold nanoparticles as the starting materials. Exposure to UV irradiation led to effective covalent cross-linking between the diacetylene moieties of neighboring ligands and hence marked enhancement of the structural integrity of the Janus nanoparticles, which was attributable to the impeded surface diffusion of the thiol ligands on the nanoparticle surface, as manifested in fluorescence measurements of aged nanoparticles. More complicated bimetallic AgAu Janus nanoparticles were prepared by interfacial galvanic exchange reactions of a Langmuir-Blodgett monolayer of 1-hexanethiolate-passivated silver nanoparticles on a glass slide with gold(I)-mercaptopropanediol complex in a water/ethanol solution. The resulting nanoparticles exhibited an asymmetrical distribution not only of the organic capping ligands on the nanoparticle surface but

  2. Engineering of aerosol nanoparticle architectures

    NASA Astrophysics Data System (ADS)

    Jiang, Xingmao

    Aerosol-assisted evaporation-induced self-assembly has been applied to fabricate a wide range of nanoparticle architectures. Ordered core-shell Ce/silica particles are effective for corrosion inhibition of aluminum alloy AA2024-T3. Higher hydrophobicity derived by increasing methyltrimethoxysilane/tetramethoxysilane ratio in the precursor delays the release in water and improves the hydrothermal stability significantly. Long-term corrosion inhibition can be realized using microporous encapsulating materials. A mathematical model has been developed to evaluate the release behavior and obtain the effective diffusion coefficient. To realize a long-term controlled release, low diffusivity and low solubility of the encapsulated cerium compound in the release medium are desirable. To maintain an effective cerium concentration for corrosion protection, a proper formulation of quick-release particles and slow-release particles may be strategically necessary. NaCl is selected as a model salt to investigate the diffusion of ions in nanoporous silica and the formation mechanism for the core-shell structure. Ordered nonporous silica with single crystal NaCl core has also been prepared. Azobenzene ligands have been uniformly anchored to the pore surfaces of the nanoporous silica particles by reacting with 4-(3-triethoxysilylpropylureido) azobenzene (TSUA). The functionalization of pore surfaces by organic groups regulates the hydrophobicity and therefore the release behavior. The modified particles demonstrate a photo controlled release by trans/cis isomerization of azobenzene moieties. Long molecule solvents or polymers can be used as blockers to adjust the release behavior for a long-term controlled release. We have developed a valid simulation method and computer code for the evaporation of ethanol-water-NaCl droplets. Various parameters such as droplet size and surrounding gas temperature and pressure have been examined. The code clearly demonstrates the evolution of

  3. Engineered Gold Nanoparticles and Plant Adaptation Potential

    NASA Astrophysics Data System (ADS)

    Siddiqi, Khwaja Salahuddin; Husen, Azamal

    2016-09-01

    Use of metal nanoparticles in biological system has recently been recognised although little is known about their possible effects on plant growth and development. Nanoparticles accumulation, translocation, growth response and stress modulation in plant system is not well understood. Plants exposed to gold and gold nanoparticles have been demonstrated to exhibit both positive and negative effects. Their growth and yield vary from species to species. Cytoxicity of engineered gold nanoparticles depends on the concentration, particle size and shape. They exhibit increase in vegetative growth and yield of fruit/seed at lower concentration and decrease them at higher concentration. Studies have shown that the gold nanoparticles exposure has improved free radical scavenging potential and antioxidant enzymatic activities and alter micro RNAs expression that regulate different morphological, physiological and metabolic processes in plants. These modulations lead to improved plant growth and yields. Prior to the use of gold nanoparticles, it has been suggested that its cost may be calculated to see if it is economically feasible.

  4. Inorganic nanoparticles engineered to attack bacteria.

    PubMed

    Miller, Kristen P; Wang, Lei; Benicewicz, Brian C; Decho, Alan W

    2015-11-07

    Antibiotics were once the golden bullet to constrain infectious bacteria. However, the rapid and continuing emergence of antibiotic resistance (AR) among infectious microbial pathogens has questioned the future utility of antibiotics. This dilemma has recently fueled the marriage of the disparate fields of nanochemistry and antibiotics. Nanoparticles and other types of nanomaterials have been extensively developed for drug delivery to eukaryotic cells. However, bacteria have very different cellular architectures than eukaryotic cells. This review addresses the chemistry of nanoparticle-based antibiotic carriers, and how their technical capabilities are now being re-engineered to attack, kill, but also non-lethally manipulate the physiologies of bacteria. This review also discusses the surface functionalization of inorganic nanoparticles with small ligand molecules, polymers, and charged moieties to achieve drug loading and controllable release.

  5. Environmental Transformations of Engineered Nanoparticles: Implications for Nanoparticle Transport

    NASA Astrophysics Data System (ADS)

    Lowry, G. V.; Levard, C.; Reinsch, B.; Ma, R.; Kirschling, T.; Brown, G. E.; Tilton, R.

    2011-12-01

    Geochemical transformations that engineered nanomaterials (ENMs) may undergo in different environments very poorly characterized. Sulfidation of metallic nanoparticles (NPs), particularly class B soft metals such as Ag NPs, is expected in the environment. Transformation will alter the surface properties and fate of Ag NPs. ENMs are often coated with a polymeric coating to prevent aggregation or to provide specific functionality. These coatings dramatically impact their transport properties. The potential for biological processes to remove covalently bound polymeric coatings from nanoparticles, and the effect of coating loss on the particle's transport properties is not known. The objectives of this work were to 1) better understand the environmental conditions that would promote sufidation of class B soft metal nanoparticles (Ag NPs and ZnO NPs), and to determine the effect that this has on their surface properties and aggregation potential, and 2) to determine if microbes can access covalently bound polymeric coatings from an engineered NP, and the effect on their surface properties and aggregation potential. Ag and ZnO NPs were synthesized and characterized for size, shape, coating mass, charge, crystal structure, and chemical composition using a range of analytical methods (TEM, DLS, TGA, EPM, XAS). These particles were sulfidized in the laboratory, biosolids, and wetland soils and the transformed materials were characterized. Sulfidation was rapid in all cases and resulted in a mixed crystalline/amorphous Ag2S/Ag2O particle depending on the ratio of Ag to HS- in the system. Sulfidation decreased surface charge and displayed significant aggregation compared to the unsulfidized materials. Sulfidation also occurred in biosolids and in wetland soils. Polymer coatings covalently bound to ENMs are bioavailable. Model poly(ethylene oxide) (PEO) brush-coated nanoparticles (30 nm hydrodynamic radius) were synthesized to obtain a nanomaterial in which biodegradation was

  6. Immunogenicity and ecotoxicity of engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Maurer-Jones, Melissa Ann

    The growing use of nanoscale materials in commercially available products and therapeutics has created an urgent need to determine the toxicity of these materials so that they may be designed and employed safely. As nanoparticles have unique physical and chemical properties, the challenges in determining their physiological and environmental impact have been numerous. It is, therefore, the goal of my thesis work to employ sensitive analytical tools to fundamentally understand the how nanoparticles interact with immunologically and ecologically relevant models. My project approaches nanotoxicity studies starting with a relevant model system exposed to well-characterized nanoparticles to (1) determine if cells/organisms survive exposure using traditional toxicological assays and, if the majority survives exposure, (2) use sensitive analytical tools to determine if there are changes to critical cell/organism function. If perturbation of function is detected, (3) the mechanism or cause of changes in cell function should be determined, including assessment of nanoparticle uptake and localization. Once a mechanism of interaction is determined, this process could begin again with a modified particle that may address the toxic response. Chapter Two describes the impact of metal oxide (TiO2 and SiO2) nanoparticles on mast cells, critical immune system cells, and utilizes the sensitive technique of carbon-fiber microelectrode amperometry (CFMA) to monitor changes in the important mast cell function of exocytosis. Chapter Three expands upon Chapter Two and examines in more detail the mechanism by which TiO2 nanoparticles impact exocytotic cell function, completing the process nanotoxicity described above. From these studies, it was determined that, while nanoparticles do not decrease the viability of mast cells, there are significant changes to exocytosis upon nanoparticle exposure, and in the case of TiO2, these changes in exocytosis are correlated to nanoparticle

  7. Engineered cerium oxide nanoparticles: Effects on bacterial growth and viability

    SciTech Connect

    Pelletier, Dale A; Suresh, Anil K; Holton, Gregory A; McKeown, Catherine K; Wang, Wei; Gu, Baohua; Mortensen, Ninell P; Allison, David P; Joy, David Charles; Allison, Martin R; Brown, Steven D; Phelps, Tommy Joe; Doktycz, Mitchel John

    2010-01-01

    Interest in engineered nanostructures has risen in recent years due to their use in energy conservation strategies and biomedicine. To ensure prudent development and use of nanomaterials, the fate and effects of such engineered structures on the environment should be understood. Interactions of nanomaterials with environmental microorganisms are inevitable, but the general consequences of such interactions remain unclear. Further, standardized methods for assessing such interactions are lacking. Therefore, we have initiated a multianalytical approach to understand the interactions of synthesized nanoparticles with bacterial systems. These efforts are focused initially on cerium oxide nanoparticles and model bacteria in order to evaluate characterization procedures and the possible fate of such materials in the environment. In this study the effects of cerium oxide nanoparticles on the growth and viability of Gram-negative Escherichia coli and Shewanella oneidensis, a metal-reducing bacteria, and Gram-positive Bacillus subtilis were examined relative to particle size, growth media, pH, and dosage. A hydrothermal based synthesis procedure was used to prepare cerium oxide nanoparticles of defined sizes in order to eliminate complications originating from the use of organic solvents and surfactants. Bactericidal effects were determined by minimum inhibitory concentration, colony forming units, disc diffusion tests and Live/Dead assays. In growth inhibition experiments involving E. coli and B. subtilis, a clear strain and size-dependent inhibition was observed. S. oneidensis appeared to be unaffected by the cerium oxide nanoparticles. Transmission electron microscopy along with microarray-based transcriptional profiling have been used to understand the response mechanism of the bacteria. The use of multiple analytical approaches adds confidence to toxicity assessments while the use of different bacterial systems highlights the potential wide-ranging effects of

  8. Application of Multi-Species Microbial Bioassay to Assess the Effects of Engineered Nanoparticles in the Aquatic Environment: Potential of a Luminous Microbial Array for Toxicity Risk Assessment (LumiMARA) on Testing for Surface-Coated Silver Nanoparticles

    PubMed Central

    Jung, YounJung; Park, Chang-Beom; Kim, Youngjun; Kim, Sanghun; Pflugmacher, Stephan; Baik, Seungyun

    2015-01-01

    Four different manufactured surface-coated silver nanoparticles (AgNPs) with coating of citrate, tannic acid, polyethylene glycol, and branched polyethylenimine were used in this study. The toxicity of surface-coated AgNPs was evaluated by a luminous microbial array for toxicity risk assessment (LumiMARA) using multi-species of luminescent bacteria. The salt stability of four different AgNPs was measured by UV absorbance at 400 nm wavelength, and different surface-charged AgNPs in combination with bacteria were observed using scanning electron microscopy (SEM). Both branched polyethylenimine (BPEI)-AgNPs and polyethylene glycol (PEG)-AgNPs were shown to be stable with 2% NaCl (non-aggregation), whereas both citrate (Cit)-AgNPs and tannic acid (Tan)-AgNPs rapidly aggregated in 2% NaCl solution. The values of the 50% effective concentration (EC50) for BPEI-AgNPs in marine bacteria strains (1.57 to 5.19 mg/L) were lower than those for the other surface-coated AgNPs (i.e., Cit-AgNPs, Tan-AgNPs, and PEG-AgNPs). It appears that the toxicity of AgNPs could be activated by the interaction of positively charged AgNPs with the negatively charged bacterial cell wall from the results of LumiMARA. LumiMARA for toxicity screening has advantageous compared to a single-species bioassay and is applicable for environmental samples as displaying ranges of assessment results. PMID:26184279

  9. Wave Engine Topping Cycle Assessment

    NASA Technical Reports Server (NTRS)

    Welch, Gerard E.

    1996-01-01

    The performance benefits derived by topping a gas turbine engine with a wave engine are assessed. The wave engine is a wave rotor that produces shaft power by exploiting gas dynamic energy exchange and flow turning. The wave engine is added to the baseline turboshaft engine while keeping high-pressure-turbine inlet conditions, compressor pressure ratio, engine mass flow rate, and cooling flow fractions fixed. Related work has focused on topping with pressure-exchangers (i.e., wave rotors that provide pressure gain with zero net shaft power output); however, more energy can be added to a wave-engine-topped cycle leading to greater engine specific-power-enhancement The energy addition occurs at a lower pressure in the wave-engine-topped cycle; thus the specific-fuel-consumption-enhancement effected by ideal wave engine topping is slightly lower than that effected by ideal pressure-exchanger topping. At a component level, however, flow turning affords the wave engine a degree-of-freedom relative to the pressure-exchanger that enables a more efficient match with the baseline engine. In some cases, therefore, the SFC-enhancement by wave engine topping is greater than that by pressure-exchanger topping. An ideal wave-rotor-characteristic is used to identify key wave engine design parameters and to contrast the wave engine and pressure-exchanger topping approaches. An aerodynamic design procedure is described in which wave engine design-point performance levels are computed using a one-dimensional wave rotor model. Wave engines using various wave cycles are considered including two-port cycles with on-rotor combustion (valved-combustors) and reverse-flow and through-flow four-port cycles with heat addition in conventional burners. A through-flow wave cycle design with symmetric blading is used to assess engine performance benefits. The wave-engine-topped turboshaft engine produces 16% more power than does a pressure-exchanger-topped engine under the specified topping

  10. Spot the difference: engineered and natural nanoparticles in the environment--release, behavior, and fate.

    PubMed

    Wagner, Stephan; Gondikas, Andreas; Neubauer, Elisabeth; Hofmann, Thilo; von der Kammer, Frank

    2014-11-10

    The production and use of nanoparticles leads to the emission of manufactured or engineered nanoparticles into the environment. Those particles undergo many possible reactions and interactions in the environment they are exposed to. These reactions and the resulting behavior and fate of nanoparticles in the environment have been studied for decades through naturally occurring nanoparticulate (1-100 nm) and colloidal (1-1000 nm) substances. The knowledge gained from these investigations is nowhere near sufficiently complete to create a detailed model of the behavior and fate of engineered nanoparticles in the environment, but is a valuable starting point for the risk assessment of these novel materials. It is the aim of this Review to critically compare naturally observed processes with those found for engineered systems to identify the "nanospecific" properties of manufactured particles and describe critical knowledge gaps relevant for the risk assessment of manufactured nanomaterials in the environment.

  11. Risk assessment of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Shipelin, V. A.; Gmoshinski, I. V.; Khotimchenko, S. A.

    2015-11-01

    Nanoparticles of metallic silver (Ag) are among the most widely used products of nanotechnology. Nanosized colloidal silver (NCS) is presented in many kinds of production as solutions of particles with diameter less than 100 nm. NCS is used in a variety of fields, including food supplements, medicines, cosmetics, packaging materials, disinfectants, water filters, and many others. Problems of toxicity and related safety of NCS for humans and environmental systems are recently overestimated basing on data of numerous toxicological studies in vitro and in vivo. The article discusses the results of current studies in recent years and the data of author's own experiments on studying the safety of NCS, that allows to move on to risk assessment of this nanomaterial presented in consumer products and environmental samples.

  12. Characterization of surface hydrophobicity of engineered nanoparticles.

    PubMed

    Xiao, Yao; Wiesner, Mark R

    2012-05-15

    The surface chemistry of nanoparticles, including their hydrophobicity, is a key determinant of their fate, transport and toxicity. Engineered NPs often have surface coatings that control the surface chemistry of NPs and may dominate the effects of the nanoparticle core. Suitable characterization methods for surface hydrophobicity at the nano-scale are needed. Three types of methods, surface adsorption, affinity coefficient and contact angle, were investigated in this study with seven carbon and metal based NPs with and without coatings. The adsorption of hydrophobic molecules, Rose Bengal dye and naphthalene, on NPs was used as one measure of hydrophobicity and was compared with the relative affinity of NPs for octanol or water phases, analogous to the determination of octanol-water partition coefficients for organic molecules. The sessile drop method was adapted for measuring contact angle of a thin film of NPs. Results for these three methods were qualitatively in agreement. Aqueous-nC(60) and tetrahydrofuran-nC(60) were observed to be more hydrophobic than nano-Ag coated with polyvinylpyrrolidone or gum arabic, followed by nano-Ag or nano-Au with citrate-functionalized surfaces. Fullerol was shown to be the least hydrophobic of seven NPs tested. The advantages and limitations of each method were also discussed.

  13. Engineering nanoparticles to silence bacterial communication

    PubMed Central

    Miller, Kristen P.; Wang, Lei; Chen, Yung-Pin; Pellechia, Perry J.; Benicewicz, Brian C.; Decho, Alan W.

    2015-01-01

    The alarming spread of bacterial resistance to traditional antibiotics has warranted the study of alternative antimicrobial agents. Quorum sensing (QS) is a chemical cell-to-cell communication mechanism utilized by bacteria to coordinate group behaviors and establish infections. QS is integral to bacterial survival, and therefore provides a unique target for antimicrobial therapy. In this study, silicon dioxide nanoparticles (Si-NP) were engineered to target the signaling molecules [i.e., acylhomoserine lactones (HSLs)] used for QS in order to halt bacterial communication. Specifically, when Si-NP were surface functionalized with β-cyclodextrin (β-CD), then added to cultures of bacteria (Vibrio fischeri), whose luminous output depends upon HSL-mediated QS, the cell-to-cell communication was dramatically reduced. Reductions in luminescence were further verified by quantitative polymerase chain reaction (qPCR) analyses of luminescence genes. Binding of HSLs to Si-NPs was examined using nuclear magnetic resonance (NMR) spectroscopy. The results indicated that by delivering high concentrations of engineered NPs with associated quenching compounds, the chemical signals were removed from the immediate bacterial environment. In actively-metabolizing cultures, this treatment blocked the ability of bacteria to communicate and regulate QS, effectively silencing and isolating the cells. Si-NPs provide a scaffold and critical stepping-stone for more pointed developments in antimicrobial therapy, especially with regard to QS—a target that will reduce resistance pressures imposed by traditional antibiotics. PMID:25806030

  14. Development of a dose-controlled multiculture cell exposure chamber for efficient delivery of airborne and engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Asimakopoulou, Akrivi; Daskalos, Emmanouil; Lewinski, Nastassja; Riediker, Michael; Papaioannou, Eleni; Konstandopoulos, Athanasios G.

    2013-04-01

    In order to study the various health influencing parameters related to engineered nanoparticles as well as to soot emitted by Diesel engines, there is an urgent need for appropriate sampling devices and methods for cell exposure studies that simulate the respiratory system and facilitate associated biological and toxicological tests. The objective of the present work was the further advancement of a Multiculture Exposure Chamber (MEC) into a dose-controlled system for efficient delivery of nanoparticles to cells. It was validated with various types of nanoparticles (Diesel engine soot aggregates, engineered nanoparticles for various applications) and with state-of-the-art nanoparticle measurement instrumentation to assess the local deposition of nanoparticles on the cell cultures. The dose of nanoparticles to which cell cultures are being exposed was evaluated in the normal operation of the in vitro cell culture exposure chamber based on measurements of the size specific nanoparticle collection efficiency of a cell free device. The average efficiency in delivering nanoparticles in the MEC was approximately 82%. The nanoparticle deposition was demonstrated by Transmission Electron Microscopy (TEM). Analysis and design of the MEC employs Computational Fluid Dynamics (CFD) and true to geometry representations of nanoparticles with the aim to assess the uniformity of nanoparticle deposition among the culture wells. Final testing of the dose-controlled cell exposure system was performed by exposing A549 lung cell cultures to fluorescently labeled nanoparticles. Delivery of aerosolized nanoparticles was demonstrated by visualization of the nanoparticle fluorescence in the cell cultures following exposure. Also monitored was the potential of the aerosolized nanoparticles to generate reactive oxygen species (ROS) (e.g. free radicals and peroxides generation), thus expressing the oxidative stress of the cells which can cause extensive cellular damage or damage on DNA.

  15. Fate of Zinc and Silver Engineered Nanoparticles in Sewerage Networks

    EPA Science Inventory

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage sy...

  16. Direct Patterning of Engineered Ionic Gold Nanoparticles via Nanoimprint Lithography

    SciTech Connect

    Yu, Xi; Pham, Jonathan; Subramani, Chandramouleeswaran; Creran, Brian; Yeh, Yi-Cheun; Du, Kan; Patra, Debabrata; Miranda, Oscar; Crosby, Alfred J.; Rotello, Vincent M.

    2012-10-01

    Gold nanoparticles are engineered for direct imprinting of stable structures. This imprinting strategy provides access to new device architectures, as demonstrated through the fabrication of a prototype photoswitchable device.

  17. Engineered polymeric nanoparticles for soil remediation.

    PubMed

    Tungittiplakorn, Warapong; Lion, Leonard W; Cohen, Claude; Kim, Ju-Young

    2004-03-01

    Hydrophobic organic groundwater contaminants, such as polynuclear aromatic hydrocarbons (PAHs), sorb strongly to soils and are difficult to remove. We report here on the synthesis of amphiphilic polyurethane (APU) nanoparticles for use in remediation of soil contaminated with PAHs. The particles are made of polyurethane acrylate anionomer (UAA) or poly(ethylene glycol)-modified urethane acrylate (PMUA) precursor chains that can be emulsified and cross-linked in water. The resulting particles are of colloidal size (17-97 nm as measured by dynamic light scattering). APU particles have the ability to enhance PAH desorption and transport in a manner comparable to that of surfactant micelles, but unlike the surface-active components of micelles, the individual cross-linked precursor chains in APU particles are not free to sorb to the soil surface. Thus, the APU particles are stable independent of their concentration in the aqueous phase. In this paper we show that APU particles can be engineered to achieve desired properties. Our experimental results show that the APU particles can be designed to have hydrophobic interior regions that confer a high affinity for phenanthrene (PHEN) and hydrophilic surfaces that promote particle mobility in soil. The affinity of APU particles for contaminants such as PHEN can be controlled by changing the size of the hydrophobic segment used in the chain synthesis. The mobility of colloidal APU suspensions in soil is controlled by the charge density or the size of the pendent water-soluble chains that reside on the particle surface. Exemplary results are provided illustrating the influence of alternative APU particle formulations with respect to their efficacy for contaminant removal. The ability to control particle properties offers the potential to produce different nanoparticles optimized for varying contaminant types and soil conditions.

  18. Release, transport and toxicity of engineered nanoparticles.

    PubMed

    Soni, Deepika; Naoghare, Pravin K; Saravanadevi, Sivanesan; Pandey, Ram Avatar

    2015-01-01

    Recent developments in nanotechnology have facilitated the synthesis of novel engineered nanoparticles (ENPs) that possess new and different physicochemical properties. These ENPs have been ex tensive ly used in various commercial sectors to achieve both social and economic benefits. However. the increasing production and consumption of ENPs by many different industries has raised concerns about their possible release and accumulation in the environment. Released EN Ps may either remain suspended in the atmosphere for several years or may accumulate and eventually be modified int o other substances. Settled nanoparticles can he easily washed away during ra in s. and therefore may easily enter the food chain via water and so il. Thus. EN Ps can contaminate air. water and soil and can subsequently pose adverse risks to the health of different organisms. Studies to date indicate that ENP transport to and within the ecosystem depend on their chemical and physical properties (viz .. size. shape and solubility) . Therefore. the EN Ps display variable behavior in the environment because of their individual properties th at affect their tendency for adsorption, absorption, diffusional and colloidal interaction. The transport of EN Ps also influences their fate and chemical transformation in ecosystems. The adsorption, absorption and colloidal interaction of ENPs affect their capacity to be degraded or transformed, whereas the tendency of ENPs to agglomerate fosters their sedimentation. How widely ENPs are transported and their environmental fate influence how tox ic they may become to environmental organisms. One barrier to fully understanding how EN Ps are transformed in the environment and how best to characterize their toxicity, is related to the nature of their ultrafine structure. Experiments with different animals, pl ants, and cell lines have revealed that ENPs induce toxicity via several cellular pathways that is linked to the size. shape. surface area

  19. Fate of Zinc and Silver Engineered Nanoparticles in ...

    EPA Pesticide Factsheets

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage systems before reaching wastewater treatment plants. To address this knowledge gap, laboratory-scale systems fed with raw wastewater were used to evaluate the transformation of ZnO- and Ag-NPs within sewerage transfer networks. Two experimental systems were established and spiked with either Ag- and ZnO-NPs or with their dissolved salts, and the wastewater influent and effluent samples from both systems were thoroughly characterised. X-ray absorption spectroscopy (XAS) was used to assess the extent of the chemical transformation of both forms of Zn and Ag during transport through the model systems. The results indicated that both ZnO- and Ag-NPs underwent significant transformation during their transport through the sewerage network. Reduced sulphur species represented the most important endpoint for these NPs in the sewer with slight differences in terms of speciation; ZnO converted largely to Zn sulfide, while Ag was also sorbed to cysteine and histidine. Importantly, both ionic Ag and Ag-NPs formed secondary Ag sulfide nanoparticles in the sewerage network as revealed by TEM analysis. Ag-cysteine was also shown to be a major species in biofilms. These results were verified in the

  20. Interaction of engineered nanoparticles with toxic and essential elements

    NASA Astrophysics Data System (ADS)

    Shumakova, A. A.; Gmoshinski, I. V.; Khotimchenko, S. A.; Trushina, E. N.

    2015-11-01

    Interaction of engineered nanoparticles with toxic and essential trace elements must be taken into consideration when estimating risks of NPs presented in the natural environment. The purpose of this work was to study the possible influence of silica, titanium dioxide (rutile) and fullerenol NPs on the toxicity of cadmium and to research the status of some trace elements and related indices of immune function in experiments on laboratory animals. Young male Wistar rats received cadmium salt (1 mg/kg b.w. Cd) orally for 28 days separately or in conjunction with the said kinds of NPs in different doses. A number of effects was observed as a result of combined action of Cd together with NPs, increase in bioaccumulation of this toxic trace element in the liver was most evident. The observed effects didn't show simple dose- dependence in respect to nanomaterials that should be taken into consideration when assessing the possible risks of joint action of nanoparticles and toxic elements existing in the environment in extremely low doses. Violation of microelement homeostasis caused by the combined action of Cd and NPs can have various adverse effects, such as inhibition of T-cell immunity induced by co-administration of Cd with rutile NPs.

  1. Fate of zinc and silver engineered nanoparticles in sewerage networks.

    PubMed

    Brunetti, Gianluca; Donner, Erica; Laera, Giuseppe; Sekine, Ryo; Scheckel, Kirk G; Khaksar, Maryam; Vasilev, Krasimir; De Mastro, Giuseppe; Lombi, Enzo

    2015-06-15

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage systems before reaching wastewater treatment plants. To address this knowledge gap, laboratory-scale systems fed with raw wastewater were used to evaluate the transformation of ZnO- and Ag-NPs within sewerage transfer networks. Two experimental systems were established and spiked with either Ag- and ZnO-NPs or with their dissolved salts, and the wastewater influent and effluent samples from both systems were thoroughly characterised. X-ray absorption spectroscopy (XAS) was used to assess the extent of the chemical transformation of both forms of Zn and Ag during transport through the model systems. The results indicated that both ZnO- and Ag-NPs underwent significant transformation during their transport through the sewerage network. Reduced sulphur species represented the most important endpoint for these NPs in the sewer with slight differences in terms of speciation; ZnO converted largely to Zn sulfide, while Ag was also sorbed to cysteine and histidine. Importantly, both ionic Ag and Ag-NPs formed secondary Ag sulfide nanoparticles in the sewerage network as revealed by TEM analysis. Ag-cysteine was also shown to be a major species in biofilms. These results were verified in the field using recently developed nanoparticle in situ deployment devices (nIDDs) which were exposed directly to sewerage network conditions by immersing them into a municipal wastewater network trunk sewer and then retrieving them for XAS analysis.

  2. Promising iron oxide-based magnetic nanoparticles in biomedical engineering.

    PubMed

    Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Vo, Toi Van; Lee, Beom-Jin

    2012-12-01

    For the past few decades biomedical engineering has imprinted its significant impact on the map of science through its wide applications on many other fields. An important example obviously proving this fact is the versatile application of magnetic nanoparticles in theranostics. Due to preferable properties such as biocompatibility, non-toxicity compared to other metal derivations, iron oxide-based magnetic nanoparticles was chosen to be addressed in this review. Aim of this review is to give the readers a whole working window of these magnetic nanoparticles in the current context of science. Thus, preparation of magnetic iron oxide nanoparticles with the so-far techniques, methods of characterizing the nanoparticles as well as their most recent biomedical applications will be stated.

  3. Engineering tailored nanoparticles with microbes: quo vadis?

    PubMed

    Prasad, Ram; Pandey, Rishikesh; Barman, Ishan

    2016-01-01

    In the quest for less toxic and cleaner methods of nanomaterials production, recent developments in the biosynthesis of nanoparticles have underscored the important role of microorganisms. Their intrinsic ability to withstand variable extremes of temperature, pressure, and pH coupled with the minimal downstream processing requirements provide an attractive route for diverse applications. Yet, controlling the dispersity and facile tuning of the morphology of the nanoparticles of desired chemical compositions remains an ongoing challenge. In this Focus Review, we critically review the advances in nanoparticle synthesis using microbes, ranging from bacteria and fungi to viruses, and discuss new insights into the cellular mechanisms of such formation that may, in the near future, allow complete control over particle morphology and functionalization. In addition to serving as paradigms for cost-effective, biocompatible, and eco-friendly synthesis, microbes hold the promise for a unique template for synthesis of tailored nanoparticles targeted at therapeutic and diagnostic platform technologies.

  4. Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles

    DTIC Science & Technology

    2007-06-01

    Therapy for Breast Cancer using Targeted Engineered Nanoparticles PRINCIPAL INVESTIGATOR: Naomi J. Halas, Ph.D. CONTRACTING...5a. CONTRACT NUMBER Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles 5b. GRANT NUMBER... nanoparticles and studying the efficiency of nanoparticle attachment to cancer cells. We have demonstrated in mouse tumor models a number of diagnostic

  5. Engineering nanoparticle-protein associations for protein crystal nucleation and nanoparticle arrangement

    NASA Astrophysics Data System (ADS)

    Benoit, Denise N.

    Engineering the nanoparticle - protein association offers a new way to form protein crystals as well as new approaches for arrangement of nanoparticles. Central to this control is the nanoparticle surface. By conjugating polymers on the surface with controlled molecular weights many properties of the nanoparticle can be changed including its size, stability in buffers and the association of proteins with its surface. Large molecular weight poly(ethylene glycol) (PEG) coatings allow for weak associations between proteins and nanoparticles. These interactions can lead to changes in how proteins crystallize. In particular, they decrease the time to nucleation and expand the range of conditions over which protein crystals form. Interestingly, when PEG chain lengths are too short then protein association is minimized and these effects are not observed. One important feature of protein crystals nucleated with nanoparticles is that the nanoparticles are incorporated into the crystals. What results are nanoparticles placed at well-defined distances in composite protein-nanoparticle crystals. Crystals on the size scale of 10 - 100 micrometers exhibit optical absorbance, fluorescence and super paramagnetic behavior derivative from the incorporated nanomaterials. The arrangement of nanoparticles into three dimensional arrays also gives rise to new and interesting physical and chemical properties, such as fluorescence enhancement and varied magnetic response. In addition, anisotropic nanomaterials aligned throughout the composite crystal have polarization dependent optical properties.

  6. Engineering of magnetic DNA nanoparticles for tumor-targeted therapy

    NASA Astrophysics Data System (ADS)

    Hosseinkhani, Hossein; Chen, Yi-Ru; He, Wenjie; Hong, Po-Da; Yu, Dah-Shyong; Domb, Abraham J.

    2013-01-01

    This study aims to engineer novel targeted delivery system composed of magnetic DNA nanoparticles to be effective as an efficient targeted gene therapy vehicle for tumor therapy. A polysaccharide, dextran, was chosen as the vector of plasmid DNA-encoded NK4 that acts as an HGF-antagonist and anti-angiogenic regulator for inhibitions of tumor growth, invasion, and metastasis. Spermine (Sm) was chemically introduced to the hydroxyl groups of dextran to obtain dextran-Sm. When Fe2+ solution was added to the mixture of dextran-Sm and a plasmid DNA, homogenous DNA nanoparticles were formed via chemical metal coordination bonding with average size of 230 nm. Characterization of DNA nanoparticles was performed via dynamic light scattering measurement, electrophoretic light scattering measurement, as well as transmission electron microscope. DNA nanoparticles effectively condensed plasmid DNA into nanoparticles and enhanced the stability of DNA, while significantly improved transfection efficiency in vitro and tumor accumulation in vivo. In addition, magnetic DNA nanoparticles exhibited high efficiency in antitumor therapy with regards to tumor growth as well as survival of animals evaluated in the presence of external magnetic field. We conclude that the magnetic properties of these DNA nanoparticles would enhance the tracking of non-viral gene delivery systems when administrated in vivo in a test model. These findings suggest that DNA nanoparticles effectively deliver DNA to tumor and thereby inhibiting tumor growth.

  7. Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles

    DTIC Science & Technology

    2008-06-01

    and shell structures that can be further engineered to have highly controlled and ‘tunable’ properties. These include paramagnetic nanoparticles , which...Therapy for Breast Cancer using Targeted Engineered Nanoparticles PRINCIPAL INVESTIGATOR: Naomi J. Halas, Ph.D. CONTRACTING...5a. CONTRACT NUMBER Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles 5b. GRANT NUMBER

  8. Biocompatible nanotemplate-engineered nanoparticles containing gadolinium: stability and relaxivity of a potential MRI contrast agent.

    PubMed

    Zhu, Donghua; White, R D; Hardy, Peter A; Weerapreeyakul, Natthida; Sutthanut, Khaetthareeya; Jay, Michael

    2006-04-01

    In this article, we use a nanotemplate engineering approach to prepare biodegradable nanoparticles composed of FDA-approved materials and possessing accessible gadolinium (Gd) atoms and demonstrate their potential as a Magnetic Resonance Imaging (MRI) contrast agent. Nanoparticles containing dimyristoyl phosphoethanolamine diethylene triamine penta acetate (PE-DTPA) were prepared using 3.5 mg of Brij 78, 2.0 mg of emulsifying wax and 0.5 mg of PE-DTPA/ml from a microemulsion precursor. After the addition of GdCl3, the presence of Gd on the surface of nanoparticles was characterized using inductively coupled plasma atomic emission spectroscopy and Scanning Transmission Electron Microscopy (STEM). The in vitro relaxivities of the PE-DTPA-Gd nanoparticles in different media were assessed at different field strengths. The conditional stability constant of Gd binding to the nanoparticles was determined using competitive spectrophotometric titration. Transmetallation kinetics of the gadolinium ion from PE-DTPA-Gd nanoparticles with zinc as the competing ionic was measured using the relaxivity evolution method. Nanoparticles with a diameter of approximately 130 nm possessing surface chelating functions were made from GRAS (Generally Regarded As Safe) materials. STEM demonstrated the uniform distribution of Gd3+ on the surface of the nanoparticles. The thermodynamic binding constant for Gd3+ to the nanoparticles was approximately 10(18) M(-1) and transmetallation studies with Zn2+ yielded kinetic constants K1 and K(-1) of 0.033 and 0.022 1/h, respectively, with an equilibrium constant of 1.5. A payload of approximately 10(5) Gd/nanoparticle was achieved; enhanced relaxivities were observed, including a pH dependence of the transverse relaxivity (r2). Nanoparticles composed of materials that have been demonstrated to be hemocompatible and enzymatically metabolized and possessing accessible Gd ions on their surface induce relaxivities in the bulk water signal that make them

  9. Rationally engineered polymeric cisplatin nanoparticle for improved antitumor efficacy

    PubMed Central

    Paraskar, Abhimanyu; Soni, Shivani; Basu, Sudipta; Chitra, J; Amarasiriwardena; Lupoli, Nicola; Srivats, Shyam; Roy, Rituparna Sinha; Sengupta, Shiladitya

    2011-01-01

    The use of cisplatin, a first line chemotherapy for most cancers, is dose-limited due to nephrotoxicity. While, this toxicity can be addressed through nanotechnology, previous attempts at engineering cisplatin nanoparticles have been limited by the impact on the potency of cisplatin. Here we report the rational engineering of a novel cisplatin nanoparticle by harnessing a novel polyethylene glycol-functionalized poly-isobutylene-maleic acid (PEG-PIMA) co-polymer, which can complex with cis-platinum (II) through a monocarboxylato and a coordinate bond. We show that this complex self-assembles into a nanoparticle, and exhibit an IC50 = 0.77 ± 0.11μM comparable to that of free cisplatin (IC50 = 0.44 ± 0.09 μM). The nanoparticles are internalized into the endolysosomal compartment of cancer cells, and releases cisplatin in a pH-dependent manner. Furthermore, the nanoparticles exhibited significantly improved antitumor efficacy in a 4T1 breast cancer model in vivo with limited nephrotoxicity, which can be explained by preferential biodistribution in the tumor with reduced kidney concentrations. Our results suggest that the PEG-PIMA-cisplatin nanoparticle can emerge as an attractive solution to the challenges in cisplatin chemotherapy. PMID:21576779

  10. Engineering tenofovir loaded chitosan nanoparticles to maximize microbicide mucoadhesion.

    PubMed

    Meng, Jianing; Sturgis, Timothy F; Youan, Bi-Botti C

    2011-09-18

    The objective of this study was to engineer a model anti-HIV microbicide (tenofovir) loaded chitosan based nanoparticles (NPs). Box-Behnken design allowed to assess the influence of formulation variables on the size of NPs and drug encapsulation efficiency (EE%) that were analyzed by dynamic light scattering and UV spectroscopy, respectively. The effect of the NPs on vaginal epithelial cells and Lactobacillus crispatus viability and their mucoadhesion to porcine vaginal tissue were assessed by cytotoxicity assays and fluorimetry, respectively. In the optimal aqueous conditions, the EE% and NPs size were 5.83% and 207.97nm, respectively. With 50% (v/v) ethanol/water as alternative solvent, these two responses increased to 20% and 602 nm, respectively. Unlike small size (182nm) exhibiting burst release, drug release from medium (281 nm) and large (602 nm)-sized NPs fitted the Higuchi (r(2)=0.991) and first-order release (r(2)=0.999) models, respectively. These NPs were not cytotoxic to both the vaginal epithelial cell line and L. crispatus for 48h. When the diameter of the NPs decreased from 900 to 188 nm, the mucoadhesion increased from 6% to 12%. However, the combinatorial effect of EE% and percent mucoadhesion for larger size NPs was the highest. Overall, large-size, microbicide loaded chitosan NPs appeared to be promising nanomedicines for the prevention of HIV transmission.

  11. Fate of Engineered Nanoparticles: Implications in the Environment

    EPA Science Inventory

    The increased flux of the engineered nanoparticles (ENPs) in consumer and commercial products has become a viable threat, particularly if their release affects the environment. The aim of this paper is to review the recent literature results pertaining to the underlying mechanism...

  12. Wave rotor demonstrator engine assessment

    NASA Technical Reports Server (NTRS)

    Snyder, Philip H.

    1996-01-01

    The objective of the program was to determine a wave rotor demonstrator engine concept using the Allison 250 series engine. The results of the NASA LERC wave rotor effort were used as a basis for the wave rotor design. A wave rotor topped gas turbine engine was identified which incorporates five basic requirements of a successful demonstrator engine. Predicted performance maps of the wave rotor cycle were used along with maps of existing gas turbine hardware in a design point study. The effects of wave rotor topping on the engine cycle and the subsequent need to rematch compressor and turbine sections in the topped engine were addressed. Comparison of performance of the resulting engine is made on the basis of wave rotor topped engine versus an appropriate baseline engine using common shaft compressor hardware. The topped engine design clearly demonstrates an impressive improvement in shaft horsepower (+11.4%) and SFC (-22%). Off design part power engine performance for the wave rotor topped engine was similarly improved including that at engine idle conditions. Operation of the engine at off design was closely examined with wave rotor operation at less than design burner outlet temperatures and rotor speeds. Challenges identified in the development of a demonstrator engine are discussed. A preliminary design was made of the demonstrator engine including wave rotor to engine transition ducts. Program cost and schedule for a wave rotor demonstrator engine fabrication and test program were developed.

  13. Shape Engineered Nanoparticle Fabrication for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Nasrullah, Azeem

    Semiconductor fabrication research has developed technologies that allow for the deposition and patterning of thin films, and can be applied to many different industries, including the field of medicine. One such application is the fabrication of nanoparticles. There is a wide variety of nanoparticle-based medical diagnostics and therapies, including drug delivery and cancer imaging. Most of the nanoparticles being studied are chemically synthesized and spherical in shape, and studies have shown that other shapes can be more useful in certain applications, especially those that involve in vivo analysis and treatment. Fabrication of particles using a tool set developed from the semiconductor industry can allow for a detailed study of size and shape dependence on nanoparticle uptake in the bloodstream. Particle fabrication is achieved using thin film deposition, ion beam proximity lithography, wet etching, and lift-off, all similar to techniques commonly found in the semiconductor industry. The particles are formed using patterns developed with proximity lithography, and this represents the largest effort in this work. An ion beam, generated by a saddle-field ion source, is used to irradiate a polymeric resist with a thin membrane stencil mask placed in close proximity to the resist coated substrate in order to define the pattern. A saddle-field ion source was constructed and characterized for proximity lithography, with a beam diameter of 4.8 mm for a +/-5% tolerance in current density, a source size range of 0.3--0.9 mm, an average brightness value of 15 nAcm2˙sr , and average exposure times of ≈30 s. Stencil masks were fabricated from silicon nitride membranes in order to generate the pattern for the nanoparticles, and the particles were fabricated using a bi-layer resist and a sacrificial copper layer for release into solution.

  14. Competitiveness assessment of engineering products

    NASA Astrophysics Data System (ADS)

    Kharisova, A. R.; Puryaev, A. S.

    2014-12-01

    This article discusses the problem of increasing the competitiveness of the engineering industry through the implementation of innovative projects. Based on the analysis of the features of innovative projects formulated a conclusion according to which the innovative projects effectiveness evaluation should take into account non-economic indicators such as social, ecological, resource, scientific and technological. We formulate the process and provide a methodology to evaluate the effectiveness of innovative projects based on noneconomic indicators. This technique is aimed at assessing the projects increase the competitiveness of products, which is understood as a comprehensive line of products a whole range of different physical limitations of the essence, allowing the long run to get sustainable income.

  15. Engineering Silver Nanoparticles: Towards a Tunable Antimicrobial

    NASA Astrophysics Data System (ADS)

    Puppala, Hema Lakshmi

    Overwhelming production of commercially available products containing silver nanoparticles (AgNPs) underscores the studies determining their fate in the environment. In order to regulate the use, assess the environmental impact and develop eco-responsible silver products, models that can predict AgNP toxicity based on physicochemical properties are vital. With that vision, this thesis developed well-characterized model libraries of uniform AgNPs stabilized with oleate in the range of 2-45 nm diameter with variable surface coating and investigated the dissolution properties that link AgNP structure to antimicrobial activity. High temperature organic synthesis allowed controlled growth of AgNPs (sigma<15%) by an Ostwald ripening mechanism in the first few hours, and followed by size dependent growth rates yielding uniform nanocrystals. Characterization of these materials revealed a crystalline nature, bidentate binding mode of oleate and non-oxidized pristine silver surface. Phase transfer of these AgNPs from organics to water was facilitated by encapsulation and ligand exchange methods using amphiphilic polymers and methoxy poly (ethylene glycol) (mPEGSH) respectively. Among these surface coatings, steric stabilization by mPEGSH not only helped retain their optical properties but also reduced the dissolution (<1(w/w)%) of AgNPs. This enhanced the stability in various environmentally relevant high ionic strength media (such as Hoaglands, EPA hard water and OECD medium), thereby increasing the shelf life. In addition, size, surface coating, pH of the medium and grafting density of the polymer mediated the dissolution of AgNPs. For instance, the rate of dissolution was decreased by 40% when the polymer coating possessed a mushroom conformation and increased with reducing core size. Analogous to dissolution, physicochemical properties also influenced the antimicrobial activity which were studied by minimum inhibitory concentration (MIC) and bactericidal efficacy assays

  16. Therapeutic nanoparticles from novel multiblock engineered polyesterurethanes

    NASA Astrophysics Data System (ADS)

    Mattu, C.; Boffito, M.; Sartori, S.; Ranzato, E.; Bernardi, E.; Sassi, M. P.; Di Rienzo, A. M.; Ciardelli, G.

    2012-12-01

    A novel biodegradable material belonging to the class of polyester-urethanes (PURs), based on poly(ɛ-caprolactone) (PCL) blocks, was proposed as matrix-forming material for the preparation of nanoparticles by the solvent displacement method. This method has been widely applied to prepare nanoparticles with reproducible, small size with commercially available polyesters or polyester-polyether copolymers. These carriers often displayed fast and poorly controllable release rates. In response to these problems we proposed the insertion of polyesters into a more complex microstructure, such as that of polyurethanes, characterized by the alternation of hard and soft segments, in order to modulate and control the degradation rate and release profiles. PCL-based PUR (C-BC2000) was synthesized according to a two step synthesis procedure. Commercial PCL and poly( d, l lactide) (PLA) were used as controls; and paclitaxel, a potent anti-neoplastic drug, was encapsulated inside all carriers. Carriers prepared with the new material showed no intrinsic cytotoxicity (A-431 cells), with similar size in the range 211-226 nm and surface charge as the commercial controls. Moreover, C-BC2000 nanoparticles exhibited a slightly faster degradation rate, a much higher encapsulation efficiency (89 % against 24 % and 18 % for PLA and PCL, respectively) and a longer and more controlled release profile. This study highlighted the possibility to successfully employ biodegradable polyurethanes to prepare particles for controlled drug delivery, suggesting further and extensive investigation on the introduction of different PUR formulations in this field.

  17. Engineering spatial gradients of signaling proteins using magnetic nanoparticles.

    PubMed

    Bonnemay, L; Hostachy, S; Hoffmann, C; Gautier, J; Gueroui, Z

    2013-11-13

    Intracellular biochemical reactions are often localized in space and time, inducing gradients of enzymatic activity that may play decisive roles in determining cell's fate and functions. However, the techniques available to examine such enzymatic gradients of activity remain limited. Here, we propose a new method to engineer a spatial gradient of signaling protein concentration within Xenopus egg extracts using superparamagnetic nanoparticles. We show that, upon the application of a magnetic field, a concentration gradient of nanoparticles with a tunable length extension is established within confined egg extracts. We then conjugate the nanoparticles to RanGTP, a small G-protein controlling microtubule assembly. We found that the generation of an artificial gradient of Ran-nanoparticles modifies the spatial positioning of microtubule assemblies. Furthermore, the spatial control of the level of Ran concentration allows us to correlate the local fold increase in Ran-nanoparticle concentration with the spatial positioning of the microtubule-asters. Our assay provides a bottom-up approach to examine the minimum ingredients generating polarization and symmetry breaking within cells. More generally, these results show how magnetic nanoparticles and magnetogenetic tools can be used to control the spatiotemporal dynamics of signaling pathways.

  18. Materials technology assessment for stirling engines

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R.; Watson, G. K.; Johnston, J. R.; Croft, W. J.

    1977-01-01

    A materials technology assessment of high temperature components in the improved (metal) and advanced (ceramic) Stirling engines was undertaken to evaluate the current state-of-the-art of metals and ceramics, identify materials research and development required to support the development of automotive Stirling engines, and to recommend materials technology programs to assure material readiness concurrent with engine system development programs. The most critical component for each engine is identified and some of the material problem areas are discussed.

  19. Cellular interactions with tissue-engineered microenvironments and nanoparticles

    NASA Astrophysics Data System (ADS)

    Pan, Zhi

    Tissue-engineered hydrogels composed of intermolecularlly crosslinked hyaluronan (HA-DTPH) and fibronectin functional domains (FNfds) were applied as a physiological relevant ECM mimic with controlled mechanical and biochemical properties. Cellular interactions with this tissue-engineered environment, especially physical interactions (cellular traction forces), were quantitatively measured by using the digital image speckle correlation (DISC) technique and finite element method (FEM). By correlating with other cell functions such as cell morphology and migration, a comprehensive structure-function relationship between cells and their environments was identified. Furthermore, spatiotemporal redistribution of cellular traction stresses was time-lapse measured during cell migration to better understand the dynamics of cell mobility. The results suggest that the reinforcement of the traction stresses around the nucleus, as well as the relaxation of nuclear deformation, are critical steps during cell migration, serving as a speed regulator, which must be considered in any dynamic molecular reconstruction model of tissue cell migration. Besides single cell migration, en masse cell migration was studied by using agarose droplet migration assay. Cell density was demonstrated to be another important parameter to influence cell behaviors besides substrate properties. Findings from these studies will provide fundamental design criteria to develop novel and effective tissue-engineered constructs. Cellular interactions with rutile and anatase TiO2 nanoparticles were also studied. These particles can penetrate easily through the cell membrane and impair cell function, with the latter being more damaging. The exposure to nanoparticles was found to decrease cell area, cell proliferation, motility, and contractility. To prevent this, a dense grafted polymer brush coating was applied onto the nanoparticle surface. These modified nanoparticles failed to adhere to and penetrate

  20. Ligand engineering of nanoparticle solar cells

    NASA Astrophysics Data System (ADS)

    Voros, Marton

    Semiconductor nanoparticles (NP) are promising materials to build cheap and efficient solar cells. One of the key challenges in their utilization for solar energy conversion is the control of NP surfaces and ligand-NP interfaces. Recent experiments have shown that by carefully choosing the ligands terminating the NPs, one can tailor electronic and optical absorption properties of NP assemblies, along with their transport properties. By using density functional theory based methods, we investigated how the opto-electronic properties of lead chalcogenide NPs may be tuned by using diverse organic and inorganic ligands. We interpreted experiments, and we showed that an essential prerequisite to avoid detrimental trap states is to ensure charge balance at the ligand-NP interface, possibly with the help of hydrogen treatment Work supported by the Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

  1. Lattice Engineering via Nanoparticle-DNA Frameworks

    PubMed Central

    Tian, Ye; Zhang, Yugang; Wang, Tong; Xin, Huolin L.; Li, Huilin; Gang, Oleg

    2017-01-01

    Advances in self-assembly over the last decade have demonstrated that nano- and microscale particles can be organized into a large diversity of ordered three-dimensional (3D) lattices. However, the ability to generate the desired lattice type from the same set of particles remains challenging. Here, we show that nanoparticles can be assembled into crystalline and open 3D frameworks by connecting them through designed DNA-based polyhedral frames. The well-defined geometrical shapes of the frames, combined with the DNA-assisted binding properties of their vertices, facilitate the well-defined topological connections between particles in accordance with frame geometry. With this strategy, different crystallographic lattices using the same particles can be assembled by introduction of the corresponding DNA polyhedral frames. This approach should facilitate the rational assembly of nanoscale lattices through the design of the unit cell. PMID:26901516

  2. Engineered Hybrid Nanoparticles for On-Demand Diagnostics and Therapeutics.

    PubMed

    Nguyen, Kim Truc; Zhao, Yanli

    2015-12-15

    Together with the simultaneous development of nanomaterials and molecular biology, the bionano interface brings about various applications of hybrid nanoparticles in nanomedicine. The hybrid nanoparticles not only present properties of the individual components but also show synergistic effects for specialized applications. Thus, the development of advanced hybrid nanoparticles for targeted and on-demand diagnostics and therapeutics of diseases has rapidly become a hot research topic in nanomedicine. The research focus is to fabricate novel classes of programmable hybrid nanoparticles that are precisely engineered to maximize drug concentrations in diseased cells, leading to enhanced efficacy and reduced side effects of chemotherapy for the disease treatment. In particular, the hybrid nanoparticle platforms can simultaneously target diseased cells, enable the location to be imaged by optical methods, and release therapeutic drugs to the diseased cells by command. This Account specially discusses the rational fabrication of integrated hybrid nanoparticles and their applications in diagnostics and therapeutics. For diagnostics applications, hybrid nanoparticles can be utilized as imaging agents that enable detailed visualization at the molecular level. By the use of suitable targeting ligands incorporated on the nanoparticles, targeted optical imaging may be feasible with improved performance. Novel imaging techniques such as multiphoton excitation and photoacoustic imaging using near-infrared light have been developed using the intrinsic properties of particular nanoparticles. The use of longer-wavelength excitation sources allows deeper penetration into the human body for disease diagnostics and at the same time reduces the adverse effects on normal tissues. Furthermore, multimodal imaging techniques have been achieved by combining several types of components in nanoparticles, offering higher accuracy and better spatial views, with the aim of detecting life

  3. Engineering index : a metric for assessing margin in engineered systems

    SciTech Connect

    Dolin, Ronald M.

    2002-01-01

    Inherent in most engineered products is some measure of margin or over design. Engineers often do not retain design and performance knowledge so they can quantify uncertainties and estimate how much margin their product possesses. When knowledge-capture and quantification is neither possible, nor permissible, engineers rely on cultural lore and institutionalised practices to assign nominal conditions and tolerances. Often what gets lost along the way is design intent, product requirements, and their relationship with the product's intended application. The Engineering Index was developed to assess the goodness or quality of a product.

  4. Assembly, Engineering and Applications of Virus-Based Protein Nanoparticles.

    PubMed

    Mateu, Mauricio G

    Viruses and their protein capsids can be regarded as biologically evolved nanomachines able to perform multiple, complex biological functions through coordinated mechano-chemical actions during the infectious cycle. The advent of nanoscience and nanotechnology has opened up, in the last 10 years or so, a vast number of novel possibilities to exploit engineered viral capsids as protein-based nanoparticles for multiple biomedical, biotechnological or nanotechnological applications. This chapter attempts to provide a broad, updated overview on the self-assembly and engineering of virus capsids, and on applications of virus-based nanoparticles. Different sections provide outlines on: (i) the structure, functions and properties of virus capsids; (ii) general approaches for obtaining assembled virus particles; (iii) basic principles and events related to virus capsid self-assembly; (iv) genetic and chemical strategies for engineering virus particles; (v) some applications of engineered virus particles being developed; and (vi) some examples on the engineering of virus particles to modify their physical properties, in order to improve their suitability for different uses.

  5. A quantitative recipe for engineering protein polymer nanoparticles

    PubMed Central

    Janib, S. Mohd; Pastuszka, M.; Aluri, S.; Folchman-Wagner, Z.; Hsueh, P-Y; Shi, P.; Yi-an; Cui, H.; MacKay, J.A.

    2013-01-01

    Protein polymers can assemble switchable nanostructures with emerging applications as biomaterials and nanomedicines. For example, above a critical micelle temperature (CMT) some elastin-like polypeptide (ELP) diblock copolymers assemble spherical nanoparticles, which may modulate cellular internalization and in vivo biodistribution. To achieve engineering-level control over their properties, this report explores a comprehensive library of ELP monoblock and diblock polymers. For the first time, we report that a surprisingly high core molecular weight is required for stable nanoparticle formation; furthermore, nanoparticle size depends on polymer molecular weight. A mathematical model was developed to characterize four ELP monoblock libraries and to predict the phase behavior of corresponding diblock copolymers. The CMT was almost entirely dependent on the hydrophobic core ELP, while the bulk phase transition temperature (Tt,bulk) depends predominantly on the hydrophilic block. Nanoparticle assembly was accompanied by a conversion in secondary structure of the hydrophobic block from random coil and beta-sheets to type-2 β turns. For the first time, this report enables the rational design of ELP protein polymer nanoparticles with physico-chemico properties that will be suitable for biological applications. PMID:24511327

  6. Exposure assessment approaches for engineered nanomaterials.

    PubMed

    Abbott, Linda C; Maynard, Andrew D

    2010-11-01

    Products based on nanotechnology are rapidly emerging in the marketplace, sometimes with little notice to consumers of their nanotechnology pedigree. This wide variety of nanotechnology products will result (in some cases) in unintentional human exposure to purposely engineered nanoscale materials via the dermal, inhalation, ingestion, and ocular pathways. Occupational, consumer, and environmental exposure to the nanomaterials should be characterized during the entire product lifecycle-manufacture, use, and disposal. Monitoring the fate and transport of engineered nanomaterials is complicated by the lack of detection techniques and the lack of a defined set of standardized metrics to be consistently measured. New exposure metrics may be required for engineered nanomaterials, but progress is possible by building on existing tools. An exposure metric matrix could organize existing data by relating likely exposure pathways (dermal, inhalation, ocular, ingestion) with existing measurements of important characteristics of nanoscale materials (particle number, mass, size distribution, charge). Nanomaterial characteristics not commonly measured, but shown to initiate a biological response during toxicity testing, signal a need for further research, such as the pressing need to develop monitoring devices capable of measuring those aspects of engineered nanomaterials that result in biological responses in humans. Modeling the behavior of nanoparticles may require new types of exposure models that individually track particles through the environment while keeping track of the particle shape, surface area, and other surface characteristics as the nanoparticles are transformed or become reactive. Lifecycle analysis could also be used to develop conceptual models of exposure from engineered nanomaterials.

  7. Civil Engineering Technology Needs Assessment.

    ERIC Educational Resources Information Center

    Oakland Community Coll., Farmington, MI. Office of Institutional Planning and Analysis.

    In 1991, a study was conducted by Oakland Community College (OCC) to evaluate the need for a proposed Civil Engineering Technology program. An initial examination of the literature focused on industry needs and the job market for civil engineering technicians. In order to gather information on local area employers' hiring practices and needs, a…

  8. Aquatic ecotoxicity effect of engineered aminoclay nanoparticles.

    PubMed

    Choi, Moon-Hee; Hwang, Yuhoon; Lee, Hyun Uk; Kim, Bohwa; Lee, Go-Woon; Oh, You-Kwan; Andersen, Henrik R; Lee, Young-Chul; Huh, Yun Suk

    2014-04-01

    In the present study the short term aquatic ecotoxicity of water-solubilized aminoclay nanoparticles (ANPs) of ~51±31 nm average hydrodynamic diameter was characterized. An ecotoxicological evaluation was carried out utilizing standard test organisms of different phyla and trophic levels namely the eukaryotic microalga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the bioluminescent marine bacteria Vibrio fisheri. The effective inhibitory concentration (EC50) with 95% confidence limits for the microalga was 1.29 mg/L (0.72-1.82) for the average growth rate and 0.26 mg/L (0.23-0.31) for the cell yield. The entrapping of algal cells in aggregates of ANP may play a major role in the growth inhibition of algae P. subcapitata. No inhibition was observed for V. fisheri up to 25,000 mg/L (no observed effect concentration; NOEC). For D. magna no immobilization was observed in a limit test with 100 mg/L in 24 h while in 48 h a single animal was immobilized (5% inhibition). Correspondingly, the NOEC of ANP in 24 h was 100 mg/L and the lowest observed effect concentration (LOEC) for 48 h was 100 mg/L. Therefore it can be considered to use ANP as an algal-inhibition agent at concentrations <100 mg/L without affecting or only mildly affecting other organisms including zooplanktons, but further studies on the environmental fate and chronic toxicity of ANP is needed to confirm this.

  9. Downsizing assessment of automotive Stirling engines

    NASA Technical Reports Server (NTRS)

    Knoll, R. H.; Tew, R. C., Jr.; Klann, J. L.

    1983-01-01

    A 67 kW (90 hp) Stirling engine design, sized for use in a 1984 1440 kg (3170 lb) automobile was the focal point for developing automotive Stirling engine technology. Since recent trends are towards lighter vehicles, an assessment was made of the applicability of the Stirling technology being developed for smaller, lower power engines. Using both the Philips scaling laws and a Lewis Research Center (Lewis) Stirling engine performance code, dimensional and performance characteristics were determined for a 26 kW (35 hp) and a 37 kW (50 hp) engine for use in a nominal 907 kg (2000 lb) vehicle. Key engine elements were sized and stressed and mechanical layouts were made to ensure mechanical fit and integrity of the engines. Fuel economy estimates indicated that the Stirling engine would maintain a 30 to 45 percent fuel economy advantage comparable spark ignition and diesel powered vehicles in the 1984 period.

  10. Integrated modular engine - Reliability assessment

    NASA Astrophysics Data System (ADS)

    Parsley, R. C.; Ward, T. B.

    1992-07-01

    A major driver in the increased interest in integrated modular engine configurations is the desire for ultra reliability for future rocket propulsion systems. The concept of configuring multiple sets of turbomachinery networked to multiple thrust chamber assemblies has been identified as an approach with potential to achieve significant reliability enhancement. This paper summarizes the results of a reliability study comparing networked systems vs. discrete engine installations, both with and without major module and engine redundancy. The study was conducted for gas generator, expander, and staged combustion cycles. The results are representative of either booster or upper-stage applications and are indicative of either plug or nonplug installation philosophies.

  11. The Life Cycle of Engineered Nanoparticles.

    PubMed

    González-Gálvez, David; Janer, Gemma; Vilar, Gemma; Vílchez, Alejandro; Vázquez-Campos, Socorro

    2017-01-01

    The first years in the twenty-first century have meant the inclusion of nanotechnology in most industrial sectors, from very specific sensors to construction materials. The increasing use of nanomaterials in consumer products has raised concerns about their potential risks for workers, consumers and the environment. In a comprehensive risk assessment or life cycle assessment, a life cycle schema is the starting point necessary to build up the exposure scenarios and study the processes and mechanisms driving to safety concerns. This book chapter describes the processes that usually occur at all the stages of the life cycle of the nano-enabled product, from the nanomaterial synthesis to the end-of-life of the products. Furthermore, release studies reported in literature related to these processes are briefly discussed.

  12. Viscosity of alumina nanoparticles dispersed in car engine coolant

    SciTech Connect

    Kole, Madhusree; Dey, T.K.

    2010-09-15

    The present paper, describes our experimental results on the viscosity of the nanofluid prepared by dispersing alumina nanoparticles (<50 nm) in commercial car coolant. The nanofluid prepared with calculated amount of oleic acid (surfactant) was tested to be stable for more than 80 days. The viscosity of the nanofluids is measured both as a function of alumina volume fraction and temperature between 10 and 50 C. While the pure base fluid display Newtonian behavior over the measured temperature, it transforms to a non-Newtonian fluid with addition of a small amount of alumina nanoparticles. Our results show that viscosity of the nanofluid increases with increasing nanoparticle concentration and decreases with increase in temperature. Most of the frequently used classical models severely under predict the measured viscosity. Volume fraction dependence of the nanofluid viscosity, however, is predicted fairly well on the basis of a recently reported theoretical model for nanofluids that takes into account the effect of Brownian motion of nanoparticles in the nanofluid. The temperature dependence of the viscosity of engine coolant based alumina nanofluids obeys the empirical correlation of the type: log ({mu}{sub nf}) = A exp(BT), proposed earlier by Namburu et al. (author)

  13. Engineering Mathematics Assessment Using "MapleTA"

    ERIC Educational Resources Information Center

    Jones, Ian S.

    2008-01-01

    The assessment of degree level engineering mathematics students using the computer-aided assessment package MapleTA is discussed. Experience of academic and practical issues for both online coursework and examination assessments is presented, hopefully benefiting other academics in this novel area of activity. (Contains 6 figures and 1 table.)

  14. Assessment of toxicity of nanoparticles using insects as biological models.

    PubMed

    Zhou, Yan; Rocha, Aracely; Sanchez, Carlos J; Liang, Hong

    2012-01-01

    Nanomaterials have become increasingly important in medicine, manufacturing, and consumer products. The fundamental understanding in effects of nanoparticles (NPs) on and their interactions with biomolecules and organismal systems have yet to be achieved. In this chapter, we firstly provide a brief review of the interactions between nanoparticles and biological systems. We will then provide an example by describing a novel method to assess the effects of NPs on biological systems, using insects as a model. Nanoparticles were injected into the central nervous system of the discoid cockroach (Blaberus discoidalis). It was found that insects became hyperactive compared to negative control (water injections). Our method could provide a generic method of assessing nanoparticles toxicity.

  15. Enabling performance skills: Assessment in engineering education

    NASA Astrophysics Data System (ADS)

    Ferrone, Jenny Kristina

    Current reform in engineering education is part of a national trend emphasizing student learning as well as accountability in instruction. Assessing student performance to demonstrate accountability has become a necessity in academia. In newly adopted criterion proposed by the Accreditation Board for Engineering and Technology (ABET), undergraduates are expected to demonstrate proficiency in outcomes considered essential for graduating engineers. The case study was designed as a formative evaluation of freshman engineering students to assess the perceived effectiveness of performance skills in a design laboratory environment. The mixed methodology used both quantitative and qualitative approaches to assess students' performance skills and congruency among the respondents, based on individual, team, and faculty perceptions of team effectiveness in three ABET areas: Communications Skills. Design Skills, and Teamwork. The findings of the research were used to address future use of the assessment tool and process. The results of the study found statistically significant differences in perceptions of Teamwork Skills (p < .05). When groups composed of students and professors were compared, professors were less likely to perceive student's teaming skills as effective. The study indicated the need to: (1) improve non-technical performance skills, such as teamwork, among freshman engineering students; (2) incorporate feedback into the learning process; (3) strengthen the assessment process with a follow-up plan that specifically targets performance skill deficiencies, and (4) integrate the assessment instrument and practice with ongoing curriculum development. The findings generated by this study provides engineering departments engaged in assessment activity, opportunity to reflect, refine, and develop their programs as it continues. It also extends research on ABET competencies of engineering students in an under-investigated topic of factors correlated with team

  16. Engine system assessment study using Martian propellants

    NASA Technical Reports Server (NTRS)

    Pelaccio, Dennis; Jacobs, Mark; Scheil, Christine; Collins, John

    1992-01-01

    A top-level feasibility study was conducted that identified and characterized promising chemical propulsion system designs which use two or more of the following propellant combinations: LOX/H2, LOX/CH4, and LOX/CO. The engine systems examined emphasized the usage of common subsystem/component hardware where possible. In support of this study, numerous mission scenarios were characterized that used various combinations of Earth, lunar, and Mars propellants to establish engine system requirements to assess the promising engine system design concept examined, and to determine overall exploration leverage of such systems compared to state-of-the-art cryogenic (LOX/H2) propulsion systems. Initially in the study, critical propulsion system technologies were assessed. Candidate expander and gas generator cycle LOX/H2/CO, LOX/H2/CH4, and LOX/CO/CH4 engine system designs were parametrically evaluated. From this evaluation baseline, tripropellant Mars Transfer Vehicle (MTV) LOX cooled and bipropellant Lunar Excursion Vehicle (LEV) and Mars Excursion Vehicle (MEV) engine systems were identified. Representative tankage designs for a MTV were also investigated. Re-evaluation of the missions using the baseline engine design showed that in general the slightly lower performance, smaller, lower weight gas generator cycle-based engines required less overall mission Mars and in situ propellant production (ISPP) infrastructure support compared to the larger, heavier, higher performing expander cycle engine systems.

  17. Behavior of engineered nanoparticles in aqueous solutions and porous media: Connecting experimentation to probabilistic analysis

    NASA Astrophysics Data System (ADS)

    Contreras, Carolina

    2011-12-01

    Engineered nanoparticles have enhanced products and services in the fields of medicine, energy, engineering, communications, personal care, environmental treatment, and many others. The increased use of engineered nanoparticles in consumer products will lead to these materials in natural systems, inevitably becoming a potential source of pollution. The study of the stability and mobility of these materials is fundamental to understand their behavior in natural systems and predict possible health and environmental implications. In addition, the use of probabilistic methods such as sensitivity analysis applied to the parameters controlling their behavior is useful in providing support in performing a risk assessment. This research investigated the stability and mobility of two types of metal oxide nanoparticles (aluminum oxide and titanium dioxide). The stability studies tested the effect of sand, pH 4, 7, and 10, and the NaCl in concentrations of 10mM, 25mM, 50mM, and 75mM. The mobility was tested using saturated quartz sand columns and nanoparticles suspension at pH 4 and 7 and in the presence of NaCl and CaCl2 in concentrations of 0.1mM, 1mM, and 10mM. Additionally, this work performed a sensitivity analysis of physical parameters used in mobility experiment performed for titanium dioxide and in mobility experiments taken from the literature for zero valent iron nanoparticles and fluorescent colloids to determine their effect on the value C/Co of by applying qualitative and quantitative methods. The results from the stability studies showed that titanium dioxide nanoparticles (TiO2) could remain suspended in solution for up to seven days at pH 10 and pH 7 even after settling of the sand; while for pH 4 solutions titanium settled along with the sand and after seven days no particles were observed in suspension. Other stability studies showed that nanoparticle aluminum oxide (Al2O3) and titanium dioxide (TiO2) size increased with increasing ionic strength (10 to 75

  18. Transport and retention of carbon-based engineered and natural nanoparticles through saturated porous media

    NASA Astrophysics Data System (ADS)

    Hedayati, Maryeh; Sharma, Prabhakar; Katyal, Deeksha; Fagerlund, Fritjof

    2016-03-01

    Carbon-based engineered nanoparticles have been widely used due to their small size and unique physical and chemical properties. At the same time, the toxic effects of these nanoparticles on human and fish cells have also been observed; therefore, their release and distribution into the surface and subsurface environment is a subject of concern. The aim of this research is to evaluate and compare the transports and retentions of two types of engineered nanoparticles (multiwalled carbon nanotubes and C60) and the natural carbon nanoparticles collected from a fire accident. Several laboratory experiments were conducted to observe the transport behavior of nanoparticles through a column packed with silica sand. The column experiments were intended to monitor the effect of ionic strength on transport of nanoparticles as a function of their shapes. It was observed that the mobilities of both types of engineered nanoparticles were reduced with the increasing ionic strength from 1.34 to 60 mM. However, at ionic strengths up to 10.89 mM, spherical nanoparticles were more mobile than cylindrical nanoparticles, but the mobility of the cylindrical nanoparticles became significantly higher than spherical nanoparticles at the ionic strength of 60 mM. In comparison with natural fire-born nanoparticles, both types of engineered nanoparticles were much less mobile under the selected experimental condition in this study. Furthermore, inverse modeling was used to calculate parameters such as attachment efficiency, the longitudinal dispersivity, and capacity of the solid phase for the attachment of nanoparticles. The results indicate that the combination of the shape and the solution chemistry of the NPs are responsible for the transport and the retention of nanoparticles in natural environment; however, fire-burned nanoparticles can be highly mobile at the natural groundwater chemistry.

  19. Inhibition effect of engineered silver nanoparticles to bloom forming cyanobacteria

    NASA Astrophysics Data System (ADS)

    Thuy Duong, Thi; Son Le, Thanh; Thu Huong Tran, Thi; Kien Nguyen, Trung; Ho, Cuong Tu; Hien Dao, Trong; Phuong Quynh Le, Thi; Chau Nguyen, Hoai; Dang, Dinh Kim; Thu Huong Le, Thi; Thu Ha, Phuong

    2016-09-01

    Silver nanoparticle (AgNP) has a wide range antibacterial effect and is extensively used in different aspects of medicine, food storage, household products, disinfectants, biomonitoring and environmental remediation etc. In the present study, we examined the growth inhibition effect of engineered silver nanoparticles against bloom forming cyanobacterial M. aeruginosa strain. AgNPs were synthesized by a chemical reduction method at room temperature and UV-Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM) showed that they presented a maximum absorption at 410 nm and size range between 10 and 18 nm. M. aeruginosa cells exposed during 10 d to AgNPs to a range of concentrations from 0 to 1 mg l-1. The changes in cell density and morphology were used to measure the responses of the M. aeruginosa to AgNPs. The control and treatment units had a significant difference in terms of cell density and growth inhibition (p < 0.05). Increasing the concentration of AgNPs, a reduction of the cell growths in all treatment was observed. The inhibition efficiency was reached 98.7% at higher concentration of AgNPs nanoparticles. The term half maximal effective concentration (EC50) based on the cell growth measured by absorbance at 680 nm (A680) was 0.0075 mg l-1. The inhibition efficiency was 98.7% at high concentration of AgNPs (1 mg l-1). Image of SEM and TEM reflected a shrunk and damaged cell wall indicating toxicity of silver nanoparticles toward M. aeruginosa.

  20. Vulnerability of drinking water supplies to engineered nanoparticles.

    PubMed

    Troester, Martin; Brauch, Heinz-Juergen; Hofmann, Thilo

    2016-06-01

    The production and use of engineered nanoparticles (ENPs) inevitably leads to their release into aquatic environments, with the quantities involved expected to increase significantly in the future. Concerns therefore arise over the possibility that ENPs might pose a threat to drinking water supplies. Investigations into the vulnerability of drinking water supplies to ENPs are hampered by the absence of suitable analytical methods that are capable of detecting and quantifiying ENPs in complex aqueous matrices. Analytical data concerning the presence of ENPs in drinking water supplies is therefore scarce. The eventual fate of ENPs in the natural environment and in processes that are important for drinking water production are currently being investigated through laboratory based-experiments and modelling. Although the information obtained from these studies may not, as yet, be sufficient to allow comprehensive assessment of the complete life-cycle of ENPs, it does provide a valuable starting point for predicting the significance of ENPs to drinking water supplies. This review therefore addresses the vulnerability of drinking water supplies to ENPs. The risk of ENPs entering drinking water is discussed and predicted for drinking water produced from groundwater and from surface water. Our evaluation is based on reviewing published data concerning ENP production amounts and release patterns, the occurrence and behavior of ENPs in aquatic systems relevant for drinking water supply and ENP removability in drinking water purification processes. Quantitative predictions are made based on realistic high-input case scenarios. The results of our synthesis of current knowledge suggest that the risk probability of ENPs being present in surface water resources is generally limited, but that particular local conditions may increase the probability of raw water contamination by ENPs. Drinking water extracted from porous media aquifers are not generally considered to be prone to ENP

  1. Design and cellular internalization of genetically engineered polypeptide nanoparticles displaying adenovirus knob domain

    PubMed Central

    Sun, Guoyong; Hsueh, Pang-Yu; Janib, Siti M.; Hamm-Alvarez, Sarah; MacKay, J. Andrew

    2011-01-01

    Hepatocytes and acinar cells exhibit high-efficiency, fiber-dependent internalization of adenovirus; however, viral capsids have unpredictable immunological effects and are challenging to develop into targeted drug carriers. To exploit this internalization pathway and minimize the use of viral proteins, we developed a simple gene product that self assembles nanoparticles decorated with the knob domain of adenovirus serotype 5 fiber protein. The most significant advantages of this platform include: (i) compatibility with genetic engineering; (ii) no bioconjugate chemistry is required to link fusion proteins to the nanoparticle surface; and (iii) it can direct the reversible assembly of large nanoparticles, which are monodisperse, multivalent, and biodegradable. These particles are predominantly composed from diblock copolymers of elastin-like polypeptide (ELP). ELPs have unique phase transition behavior, whereby they self-assemble above a transition temperature that is simple to control. The diblock ELP described contains two motifs with distinct transition temperatures, which assemble nanoparticles at physiological temperatures. Analysis by non-denaturing-PAGE demonstrated that the purified knob-ELP formed trimers or dimers, which is a property of the native knob/fiber protein. Dynamic light scattering indicated that the diblock copolymer, with or without knob, is able to self assemble into nanoparticles ~40 nm in diameter. To examine the functionality of knob-ELP, their uptake was assessed in a hepatocyte cell-line that expresses the receptor for adenovirus serotype 5 fiber and knob, the coxsackievirus and adenovirus receptor (CAR). Both plain ELP and knob-ELP were bound to the outside of hepatocytes; however, the knob-ELP fusion protein exhibits more internalization and localization to lysosomes of hepatocytes. These findings suggest that functional fusion proteins may only minimally influence the assembly temperature and diameter of ELP nanoparticles. These

  2. Functional enhancement of chitosan and nanoparticles in cell culture, tissue engineering, and pharmaceutical applications.

    PubMed

    Gao, Wenjuan; Lai, James C K; Leung, Solomon W

    2012-01-01

    As a biomaterial, chitosan has been widely used in tissue engineering, wound healing, drug delivery, and other biomedical applications. It can be formulated in a variety of forms, such as powder, film, sphere, gel, and fiber. These features make chitosan an almost ideal biomaterial in cell culture applications, and cell cultures arguably constitute the most practical way to evaluate biocompatibility and biotoxicity. The advantages of cell cultures are that they can be performed under totally controlled environments, allow high throughput functional screening, and are less costly, as compared to other assessment methods. Chitosan can also be modified into multilayer composite by combining with other polymers and moieties to alter the properties of chitosan for particular biomedical applications. This review briefly depicts and discusses applications of chitosan and nanoparticles in cell culture, in particular, the effects of chitosan and nanoparticles on cell adhesion, cell survival, and the underlying molecular mechanisms: both stimulatory and inhibitory influences are discussed. Our aim is to update the current status of how nanoparticles can be utilized to modify the properties of chitosan to advance the art of tissue engineering by using cell cultures.

  3. Functional enhancement of chitosan and nanoparticles in cell culture, tissue engineering, and pharmaceutical applications

    PubMed Central

    Gao, Wenjuan; Lai, James C. K.; Leung, Solomon W.

    2012-01-01

    As a biomaterial, chitosan has been widely used in tissue engineering, wound healing, drug delivery, and other biomedical applications. It can be formulated in a variety of forms, such as powder, film, sphere, gel, and fiber. These features make chitosan an almost ideal biomaterial in cell culture applications, and cell cultures arguably constitute the most practical way to evaluate biocompatibility and biotoxicity. The advantages of cell cultures are that they can be performed under totally controlled environments, allow high throughput functional screening, and are less costly, as compared to other assessment methods. Chitosan can also be modified into multilayer composite by combining with other polymers and moieties to alter the properties of chitosan for particular biomedical applications. This review briefly depicts and discusses applications of chitosan and nanoparticles in cell culture, in particular, the effects of chitosan and nanoparticles on cell adhesion, cell survival, and the underlying molecular mechanisms: both stimulatory and inhibitory influences are discussed. Our aim is to update the current status of how nanoparticles can be utilized to modify the properties of chitosan to advance the art of tissue engineering by using cell cultures. PMID:22934070

  4. A Global Assessment of Stem Cell Engineering

    PubMed Central

    Loring, Jeanne F.; McDevitt, Todd C.; Palecek, Sean P.; Schaffer, David V.; Zandstra, Peter W.

    2014-01-01

    Over the last 2 years a global assessment of stem cell engineering (SCE) was conducted with the sponsorship of the National Science Foundation, the National Cancer Institute at the National Institutes of Health, and the National Institute of Standards and Technology. The purpose was to gather information on the worldwide status and trends in SCE, that is, the involvement of engineers and engineering approaches in the stem cell field, both in basic research and in the translation of research into clinical applications and commercial products. The study was facilitated and managed by the World Technology Evaluation Center. The process involved site visits in both Asia and Europe, and it also included several different workshops. From this assessment, the panel concluded that there needs to be an increased role for engineers and the engineering approach. This will provide a foundation for the generation of new markets and future economic growth. To do this will require an increased investment in engineering, applied research, and commercialization as it relates to stem cell research and technology. It also will require programs that support interdisciplinary teams, new innovative mechanisms for academic–industry partnerships, and unique translational models. In addition, the global community would benefit from forming strategic partnerships between countries that can leverage existing and emerging strengths in different institutions. To implement such partnerships will require multinational grant programs with appropriate review mechanisms. PMID:24428577

  5. A global assessment of stem cell engineering.

    PubMed

    Loring, Jeanne F; McDevitt, Todd C; Palecek, Sean P; Schaffer, David V; Zandstra, Peter W; Nerem, Robert M

    2014-10-01

    Over the last 2 years a global assessment of stem cell engineering (SCE) was conducted with the sponsorship of the National Science Foundation, the National Cancer Institute at the National Institutes of Health, and the National Institute of Standards and Technology. The purpose was to gather information on the worldwide status and trends in SCE, that is, the involvement of engineers and engineering approaches in the stem cell field, both in basic research and in the translation of research into clinical applications and commercial products. The study was facilitated and managed by the World Technology Evaluation Center. The process involved site visits in both Asia and Europe, and it also included several different workshops. From this assessment, the panel concluded that there needs to be an increased role for engineers and the engineering approach. This will provide a foundation for the generation of new markets and future economic growth. To do this will require an increased investment in engineering, applied research, and commercialization as it relates to stem cell research and technology. It also will require programs that support interdisciplinary teams, new innovative mechanisms for academic-industry partnerships, and unique translational models. In addition, the global community would benefit from forming strategic partnerships between countries that can leverage existing and emerging strengths in different institutions. To implement such partnerships will require multinational grant programs with appropriate review mechanisms.

  6. Structural-Engineering Rationales of Gold Nanoparticles for Cancer Theranostics.

    PubMed

    Chen, Wenwen; Zhang, Shaohua; Yu, Yangyang; Zhang, Huisheng; He, Qianjun

    2016-10-01

    Personalized theranostics of cancer is increasingly desired, and can be realized by virtue of multifunctional nanomaterials with possible high performances. Gold nanoparticles (GNPs) are a type of especially promising candidate for cancer theranostics, because their synthesis and modification are facile, their structures and physicochemical properties are flexibly controlled, and they are also biocompatible. Especially, the localized surface plasmon resonance and multivalent coordination effects on the surface endow them with NIR light-triggered photothermal imaging and therapy, controlled drug release, and targeted drug delivery. Although the structure, properties, and theranostic application of GNPs are considerably plentiful, no expert review systematically explains the relationships among their structure, property. and application and induces the engineering rationales of GNPs for cancer theranostics. Hence, there are no clear rules to guide the facile construction of optimal GNP structures aiming at a specific theranostic application. A series of structural-engineering rationales of GNPs for cancer theranostics is proposed through digging out the deep relationships between the structure and properties of GNPs. These rationales will be inspiring for guiding the engineering of specific and advanced GNPs for personalized cancer theranostics.

  7. Safety assessment of chronic oral exposure to iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Chamorro, Susana; Gutiérrez, Lucía; Vaquero, María Pilar; Verdoy, Dolores; Salas, Gorka; Luengo, Yurena; Brenes, Agustín; José Teran, Francisco

    2015-05-01

    Iron oxide nanoparticles with engineered physical and biochemical properties are finding a rapidly increasing number of biomedical applications. However, a wide variety of safety concerns, especially those related to oral exposure, still need to be addressed for iron oxide nanoparticles in order to reach clinical practice. Here, we report on the effects of chronic oral exposure to low doses of γ-Fe2O3 nanoparticles in growing chickens. Animal observation, weight, and diet intake reveal no adverse signs, symptoms, or mortality. No nanoparticle accumulation was observed in liver, spleen, and duodenum, with feces as the main excretion route. Liver iron level and duodenal villi morphology reflect the bioavailability of the iron released from the partial transformation of γ-Fe2O3 nanoparticles in the acid gastric environment. Duodenal gene expression studies related to the absorption of iron from γ-Fe2O3 nanoparticles indicate the enhancement of a ferric over ferrous pathway supporting the role of mucins. Our findings reveal that oral administration of iron oxide nanoparticles is a safe route for drug delivery at low nanoparticle doses.

  8. GFO Altimeter Engineering Assessment Report

    NASA Technical Reports Server (NTRS)

    Lockwood, Dennis W.; Hancock, David W., III; Hayne, George S.; Brooks, Ronald L.

    2002-01-01

    The U.S. Navy's Geosat Follow-On (GFO) Mission, launched on February 20, 1998, is one of a series of altimetric satellites which include Seasat, Geosat, ERS-1, and TOPEX/POSEIDON (T/P). The purpose of this report is to document the GFO altimeter performance determined from the analyses and results performed by NASA's GSFC and Wallops altimeter, calibration team. It is the second of an anticipated series of NASA's GSFC and Wallops GFO performance documents, each of which will update assessment results. This report covers the performance from instrument acceptance by the Navy on November 29, 2000, to the end of Cycle 20 on November 21, 2001. Data derived from GFO will lead to improvements in the knowledge of ocean circulation, ice sheet topography, and climate change. In order to capture the maximum amount of information from the GFO data, accurate altimeter calibrations are required for the civilian data set which NOAA will produce. Wallops Flight Facility has provided similar products for the Geosat and T/P missions and is doing the same for GFO.

  9. Engineering Metallic Nanoparticles for Enhancing and Probing Catalytic Reactions.

    PubMed

    Collins, Gillian; Holmes, Justin D

    2016-07-01

    Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs.

  10. Engineered silica nanoparticles as additives in lubricant oils

    NASA Astrophysics Data System (ADS)

    Díaz-Faes López, Teresa; Fernández González, Alfonso; Del Reguero, Ángel; Matos, María; Díaz-García, Marta E.; Badía-Laíño, Rosana

    2015-10-01

    Silica nanoparticles (SiO2 NPs) synthesized by the sol-gel approach were engineered for size and surface properties by grafting hydrophobic chains to prevent their aggregation and facilitate their contact with the phase boundary, thus improving their dispersibility in lubricant base oils. The surface modification was performed by covalent binding of long chain alkyl functionalities using lauric acid and decanoyl chloride to the SiO2 NP surface. The hybrid SiO2 NPs were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, simultaneous differential thermal analysis, nuclear magnetic resonance and dynamic light scattering, while their dispersion in two base oils was studied by static multiple light scattering at low (0.01% w/v) and high (0.50%w/v) concentrations. The nature of the functional layer and the functionalization degree seemed to be directly involved in the stability of the suspensions. The potential use of the functional SiO2 NPs as lubricant additives in base oils, specially designed for being used in hydraulic circuits, has been outlined by analyzing the tribological properties of the dispersions. The dendritic structure of the external layer played a key role in the tribological characteristics of the material by reducing the friction coefficient and wear. These nanoparticles reduce drastically the waste of energy in friction processes and are more environmentally friendly than other additives.

  11. Engineered silica nanoparticles as additives in lubricant oils

    PubMed Central

    López, Teresa Díaz-Faes; González, Alfonso Fernández; Del Reguero, Ángel; Matos, María; Díaz-García, Marta E; Badía-Laíño, Rosana

    2015-01-01

    Silica nanoparticles (SiO2 NPs) synthesized by the sol–gel approach were engineered for size and surface properties by grafting hydrophobic chains to prevent their aggregation and facilitate their contact with the phase boundary, thus improving their dispersibility in lubricant base oils. The surface modification was performed by covalent binding of long chain alkyl functionalities using lauric acid and decanoyl chloride to the SiO2 NP surface. The hybrid SiO2 NPs were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, simultaneous differential thermal analysis, nuclear magnetic resonance and dynamic light scattering, while their dispersion in two base oils was studied by static multiple light scattering at low (0.01% w/v) and high (0.50%w/v) concentrations. The nature of the functional layer and the functionalization degree seemed to be directly involved in the stability of the suspensions. The potential use of the functional SiO2 NPs as lubricant additives in base oils, specially designed for being used in hydraulic circuits, has been outlined by analyzing the tribological properties of the dispersions. The dendritic structure of the external layer played a key role in the tribological characteristics of the material by reducing the friction coefficient and wear. These nanoparticles reduce drastically the waste of energy in friction processes and are more environmentally friendly than other additives. PMID:27877840

  12. Assessing graduate student progress in engineering ethics.

    PubMed

    Davis, Michael; Feinerman, Alan

    2012-06-01

    Under a grant from the National Science Foundation, the authors (and others) undertook to integrate ethics into graduate engineering classes at three universities-and to assess success in a way allowing comparison across classes (and institutions). This paper describes the attempt to carry out that assessment. Standard methods of assessment turned out to demand too much class time. Under pressure from instructors, the authors developed an alternative method that is both specific in content to individual classes and allows comparison across classes. Results are statistically significant for ethical sensitivity and knowledge. They show measurable improvement in a single semester.

  13. Synthesis and optimization of chitosan nanoparticles: Potential applications in nanomedicine and biomedical engineering

    PubMed Central

    Ghadi, Arezou; Mahjoub, Soleiman; Tabandeh, Fatemeh; Talebnia, Farid

    2014-01-01

    Background: Chitosan nanoparticles have become of great interest for nanomedicine, biomedical engineering and development of new therapeutic drug release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity. The aim of the present study was to synthesis and optimize of the chitosan nanoparticles for industrial and biomedical applications. Methods: Fe3O4 was synthesized and optimized as magnetic core nanoparticles and then chitosan covered this magnetic core. The size and morphology of the nano-magnetic chitosan was analyzed by scanning electron microscope (SEM). Topography and size distribution of the nanoparticles were shown with two-dimensional and three-dimensional images of atomic force microscopy (AFM). The nanoparticles were analyzed using transmission electron microscopy (TEM). Results: The chitosan nanoparticles prepared in the experiment exhibited white powder shape. The SEM micrographs of the nano-magnetic chitosan showed that they were approximately uniform spheres. The unmodified chitosan nanoparticles composed of clusters of nanoparticles with sizes ranging from 10 nm to 80 nm. AFM provides a three-dimensional surface profile. The TEM image showed physical aggregation of the chitosan nanoparticles. Conclusion: The results show that a novel chitosan nanoparticle was successfully synthesized and characterized. It seems that this nanoparticle like the other chitosan nano particles has potential applications for nanomedicine, biomedical engineering, industrial and pharmaceutical fields. PMID:25202443

  14. Ordered nanoparticle arrays formed on engineered chaperonin protein templates

    NASA Technical Reports Server (NTRS)

    McMillan, R. Andrew; Paavola, Chad D.; Howard, Jeanie; Chan, Suzanne L.; Zaluzec, Nestor J.; Trent, Jonathan D.

    2002-01-01

    Traditional methods for fabricating nanoscale arrays are usually based on lithographic techniques. Alternative new approaches rely on the use of nanoscale templates made of synthetic or biological materials. Some proteins, for example, have been used to form ordered two-dimensional arrays. Here, we fabricated nanoscale ordered arrays of metal and semiconductor quantum dots by binding preformed nanoparticles onto crystalline protein templates made from genetically engineered hollow double-ring structures called chaperonins. Using structural information as a guide, a thermostable recombinant chaperonin subunit was modified to assemble into chaperonins with either 3 nm or 9 nm apical pores surrounded by chemically reactive thiols. These engineered chaperonins were crystallized into two-dimensional templates up to 20 microm in diameter. The periodic solvent-exposed thiols within these crystalline templates were used to size-selectively bind and organize either gold (1.4, 5 or 10nm) or CdSe-ZnS semiconductor (4.5 nm) quantum dots into arrays. The order within the arrays was defined by the lattice of the underlying protein crystal. By combining the self-assembling properties of chaperonins with mutations guided by structural modelling, we demonstrate that quantum dots can be manipulated using modified chaperonins and organized into arrays for use in next-generation electronic and photonic devices.

  15. Systemic delivery to central nervous system by engineered PLGA nanoparticles

    PubMed Central

    Cai, Qiang; Wang, Long; Deng, Gang; Liu, Junhui; Chen, Qianxue; Chen, Zhibiao

    2016-01-01

    Neurological disorders are an important global public health problem, but pharmaceutical treatments are limited due to drug access to the central nervous system being restricted by the blood-brain barrier (BBB). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are one of the most promising drug and gene delivery systems for crossing the BBB. While these systems offer great promise, PLGA NPs also have some intrinsic drawbacks and require further engineering for clinical and research applications. Multiple strategies have been developed for using PLGA NPs to deliver compounds across the BBB. We classify these strategies into three categories according to the adaptations made to the PLGA NPs (1) to facilitate travel from the injection site (pre-transcytosis strategies); (2) to enhance passage across the brain endothelial cells (BBB transcytosis strategies) and (3) to achieve targeting of the impaired nervous system cells (post-transcytosis strategies). PLGA NPs modified according to these three strategies are denoted first, second, and third generation NPs, respectively. We believe that fusing these three strategies to engineer multifunctional PLGA NPs is the only way to achieve translational applications. PMID:27158367

  16. Engineering structured light with Vogel spiral arrays of nanoparticles

    NASA Astrophysics Data System (ADS)

    Lawrence, Nate; Trevino, Jacob; Dal Negro, Luca

    2013-03-01

    We present a general analytical model for light scattering by arbitrary Vogel spiral arrays of circular apertures uniformly illuminated at normal incidence. This model suffices to unveil the fundamental mathematical structure of their complex Fraunhofer diffraction patterns and enables the engineering of optical beams carrying multiple values of orbital angular momentum (OAM). By performing analytical Fourier-Hankel decomposition of spiral arrays and far field patterns, we rigorously demonstrate the ability to encode specific numerical sequences onto the OAM values of diffracted optical beams. In particular, we show that these OAM values are determined by the rational approximations of the continued fraction expansions of the irrational angles utilized to generate Vogel spirals. Finally, we experimentally demonstrate structured light carrying multiple values of OAM in the far-field scattering region of Vogel spiral arrays of metallic nanoparticles. Using Fourier-Hankel mode decomposition analysis and interferometric reconstruction of the complex amplitude of scattered waves, we show the ability to encode well-defined numerical sequences, determined by the aperiodic spiral geometry, into azimuthal OAM values, in excellent agreement with analytical scattering theory. The generation of sequences of OAM values by light scattering from engineered aperiodic surfaces is relevant to a number of device applications for secure optical communication, classical and quantum cryptography.

  17. Strategies in biomimetic surface engineering of nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Gong, Yong-Kuan; Winnik, Françoise M.

    2012-01-01

    Engineered nanoparticles (NPs) play an increasingly important role in biomedical sciences and in nanomedicine. Yet, in spite of significant advances, it remains difficult to construct drug-loaded NPs with precisely defined therapeutic effects, in terms of release time and spatial targeting. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Upon injection in the blood stream or following oral administation, NPs have to bypass numerous barriers prior to reaching their intended target. A particularly successful design strategy consists in masking the NP to the biological environment by covering it with an outer surface mimicking the composition and functionality of the cell's external membrane. This review describes this biomimetic approach. First, we outline key features of the composition and function of the cell membrane. Then, we present recent developments in the fabrication of molecules that mimic biomolecules present on the cell membrane, such as proteins, peptides, and carbohydrates. We present effective strategies to link such bioactive molecules to the NPs surface and we highlight the power of this approach by presenting some exciting examples of biomimetically engineered NPs useful for multimodal diagnostics and for target-specific drug/gene delivery applications. Finally, critical directions for future research and applications of biomimetic NPs are suggested to the readers.

  18. Effects of Engineered Cerium Oxide Nanoparticles on Bacterial Growth and Viability▿†

    PubMed Central

    Pelletier, Dale A.; Suresh, Anil K.; Holton, Gregory A.; McKeown, Catherine K.; Wang, Wei; Gu, Baohua; Mortensen, Ninell P.; Allison, David P.; Joy, David C.; Allison, Martin R.; Brown, Steven D.; Phelps, Tommy J.; Doktycz, Mitchel J.

    2010-01-01

    Interest in engineered nanostructures has risen in recent years due to their use in energy conservation strategies and biomedicine. To ensure prudent development and use of nanomaterials, the fate and effects of such engineered structures on the environment should be understood. Interactions of nanomaterials with environmental microorganisms are inevitable, but the general consequences of such interactions remain unclear, due to a lack of standard methods for assessing such interactions. Therefore, we have initiated a multianalytical approach to understand the interactions of synthesized nanoparticles with bacterial systems. These efforts are focused initially on cerium oxide nanoparticles and model bacteria in order to evaluate characterization procedures and the possible fate of such materials in the environment. The growth and viability of the Gram-negative species Escherichia coli and Shewanella oneidensis, a metal-reducing bacterium, and the Gram-positive species Bacillus subtilis were examined relative to cerium oxide particle size, growth media, pH, and dosage. A hydrothermal synthesis approach was used to prepare cerium oxide nanoparticles of defined sizes in order to eliminate complications originating from the use of organic solvents and surfactants. Bactericidal effects were determined from MIC and CFU measurements, disk diffusion tests, and live/dead assays. For E. coli and B. subtilis, clear strain- and size-dependent inhibition was observed, whereas S. oneidensis appeared to be unaffected by the particles. Transmission electron microscopy along with microarray-based transcriptional profiling was used to understand the response mechanism of the bacteria. Use of multiple analytical approaches adds confidence to toxicity assessments, while the use of different bacterial systems highlights the potential wide-ranging effects of nanomaterial interactions in the environment. PMID:20952651

  19. Magnetic Nanoparticles: Material Engineering and Emerging Applications in Lithography and Biomedicine

    PubMed Central

    Bao, Yuping; Wen, Tianlong; Samia, Anna Cristina S.; Khandhar, Amit; Krishnan, Kannan M.

    2015-01-01

    We present an interdisciplinary overview of material engineering and emerging applications of iron oxide nanoparticles. We discuss material engineering of nanoparticles in the broadest sense, emphasizing size and shape control, large-area self-assembly, composite/hybrid structures, and surface engineering. This is followed by a discussion of several non-traditional, emerging applications of iron oxide nanoparticles, including nanoparticle lithography, magnetic particle imaging, magnetic guided drug delivery, and positive contrast agents for magnetic resonance imaging. We conclude with a succinct discussion of the pharmacokinetics pathways of iron oxide nanoparticles in the human body –– an important and required practical consideration for any in vivo biomedical application, followed by a brief outlook of the field. PMID:26586919

  20. Tiger Team Assessment, Energy Technology Engineering Center

    SciTech Connect

    Not Available

    1991-04-01

    The Office Special Projects within the Office of Environment, Safety, and Health (EH) has the responsibility to conduct Tiger Team Assessments for the Secretary of Energy. This report presents the assessment of the buildings, facilities, and activities under the DOE/Rockwell Contract No. DE-AM03-76SF00700 for the Energy Technology Engineering Center (ETEC) and of other DOE-owned buildings and facilities at the Santa Susana Field Laboratory (SSFL) site in southeastern Ventura County, California, not covered under Contract No. DE-AM03-76SF00700, but constructed over the years under various other contracts between DOE and Rockwell International. ETEC is an engineering development complex operated for DOE by the Rocketdyne Division of Rockwell International Corporation. ETEC is located within SSFL on land owned by Rockwell. The balance of the SSFL complex is owned and operated by Rocketdyne, with the exception of a 42-acre parcel owned by the National Aeronautics and Space Administration (NASA). The primary mission of ETEC is to provide engineering, testing, and development of components related to liquid metals technology and to conduct applied engineering development of emerging energy technologies.

  1. Space transportation main engine cycle assessment process

    NASA Technical Reports Server (NTRS)

    Mcconnaughey, H. V.; Lyles, G. M.

    1991-01-01

    The Advanced Launch System (ALS) program selection process for a space transportation main engine (STME) power cycle is described in terms of the methodology employed. Low cost, robustness, and high reliability are the primary parameters for engine choice, suggesting simplicity of design and efficient fabrication methods as the crucial characteristics. An evaluation methodology is developed based on the Pugh (1981) process and the King (1989) matrices. The cycle configurations considered are the gas generator (GG), the closed expander, and the open expander. The cycle assessment team determined that the GG cycle is favored by most cycle discriminators, based on an assessment of the characteristics in terms of ALS goals. The lower development risk of the GG-cycle STME is consistent with the goals of the ALS program in terms of reliability and cost efficiency.

  2. Systems engineering process and organization assessment

    NASA Technical Reports Server (NTRS)

    Batson, Robert G.

    1992-01-01

    The purpose of this report is to briefly summarize the results of an eight week assessment of NASA/MSFC Phase A and Phase B systems engineering processes, methodologies, and activities. Specifically, fourteen inconsistencies or weaknesses were identified and recommendations for corrective action were generated. A 1.5 hour briefing on these results was given in EL51 on 8-11-92; that documentation is available from the author or either NASA Colleague.

  3. Mobility of engineered inorganic nanoparticles in porous media

    NASA Astrophysics Data System (ADS)

    Metreveli, George; Heidmann, Ilona; Schaumann, Gabriele Ellen

    2013-04-01

    Besides the excellent properties and great potential for various industrial, medical, pharmaceutical, cosmetic, and life science applications, engineered inorganic nanoparticles (EINP) can show also disadvantages concerning increasing risk potential with increasing application, if they are released in the environmental systems. EINP can influence microbial activity and can show toxic effects (Fabrega et al., 2009). Similar to the inorganic natural colloids, EINP can be transported in soil and groundwater systems (Metreveli et al., 2005). Furthermore, due to the large surface area and high sorption and complex formation capacity, EINP can facilitate transport of different contaminants. In this study the mobility behaviour of EINP and their effect on the transport of different metal(loid) species in water saturated porous media was investigated. For these experiments laboratory column system was used. The column was filled with quartz sand. The interactions between EINP and metal(loid)s were characterised by coupling of asymmetrical flow field flow fractionation (AF4) with inductively coupled plasma mass spectrometer (ICP-MS). As EINP laponite (synthetic three layer clay mineral), and as metal(loid)s Cu, Pb, Zn, Pt and As were used. In AF4 experiments sorption of metal(loid)s on the surface of EINP could be observed. The extent of interactions was influenced by pH value and was different for different metal(loid)s. Laboratory column experiments showed high mobility of EINP, which facilitated transport of most of metal(loid)s in water saturated porous media. Furthermore the migration of synthetic silver nanoparticles in natural soil columns was determined in leaching experiments. Acknowledgement Financial support by German Research Council (DFG) and Max-Buchner-Research Foundation (MBFSt) is gratefully acknowledged. We thank Karlsruhe Institute of Technology (KIT) for the opportunity to perform the column and AF4 experiments. References: Fabrega, J., Fawcett, S. R

  4. Engineering of Hollow Mesoporous Silica Nanoparticles for Remarkably Enhanced Tumor Active Targeting Efficacy

    PubMed Central

    Chen, Feng; Hong, Hao; Shi, Sixiang; Goel, Shreya; Valdovinos, Hector F.; Hernandez, Reinier; Theuer, Charles P.; Barnhart, Todd E.; Cai, Weibo

    2014-01-01

    Hollow mesoporous silica nanoparticle (HMSN) has recently gained increasing interests due to their tremendous potential as an attractive nano-platform for cancer imaging and therapy. However, possibly due to the lack of efficient in vivo targeting strategy and well-developed surface engineering techniques, engineering of HMSN for in vivo active tumor targeting, quantitative tumor uptake assessment, multimodality imaging, biodistribution and enhanced drug delivery have not been achieved to date. Here, we report the in vivo tumor targeted positron emission tomography (PET)/near-infrared fluorescence (NIRF) dual-modality imaging and enhanced drug delivery of HMSN using a generally applicable surface engineering technique. Systematic in vitro and in vivo studies have been performed to investigate the stability, tumor targeting efficacy and specificity, biodistribution and drug delivery capability of well-functionalized HMSN nano-conjugates. The highest uptake of TRC105 (which binds to CD105 on tumor neovasculature) conjugated HMSN in the 4T1 murine breast cancer model was ~10%ID/g, 3 times higher than that of the non-targeted group, making surface engineered HMSN a highly attractive drug delivery nano-platform for future cancer theranostics. PMID:24875656

  5. Toxicological Considerations, Toxicity Assessment, and Risk Management of Inhaled Nanoparticles

    PubMed Central

    Bakand, Shahnaz; Hayes, Amanda

    2016-01-01

    Novel engineered nanoparticles (NPs), nanomaterial (NM) products and composites, are continually emerging worldwide. Many potential benefits are expected from their commercial applications; however, these benefits should always be balanced against risks. Potential toxic effects of NM exposure have been highlighted, but, as there is a lack of understanding about potential interactions of nanomaterials (NMs) with biological systems, these side effects are often ignored. NPs are able to translocate to the bloodstream, cross body membrane barriers effectively, and affect organs and tissues at cellular and molecular levels. NPs may pass the blood–brain barrier (BBB) and gain access to the brain. The interactions of NPs with biological milieu and resulted toxic effects are significantly associated with their small size distribution, large surface area to mass ratio (SA/MR), and surface characteristics. NMs are able to cross tissue and cell membranes, enter into cellular compartments, and cause cellular injury as well as toxicity. The extremely large SA/MR of NPs is also available to undergo reactions. An increased surface area of the identical chemical will increase surface reactivity, adsorption properties, and potential toxicity. This review explores biological pathways of NPs, their toxic potential, and underlying mechanisms responsible for such toxic effects. The necessity of toxicological risk assessment to human health should be emphasised as an integral part of NM design and manufacture. PMID:27314324

  6. Automated Power Assessment for Helicopter Turboshaft Engines

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Litt, Jonathan S.

    2008-01-01

    An accurate indication of available power is required for helicopter mission planning purposes. Available power is currently estimated on U.S. Army Blackhawk helicopters by performing a Maximum Power Check (MPC), a manual procedure performed by maintenance pilots on a periodic basis. The MPC establishes Engine Torque Factor (ETF), an indication of available power. It is desirable to replace the current manual MPC procedure with an automated approach that will enable continuous real-time assessment of available power utilizing normal mission data. This report presents an automated power assessment approach which processes data currently collected within helicopter Health and Usage Monitoring System (HUMS) units. The overall approach consists of: 1) a steady-state data filter which identifies and extracts steady-state operating points within HUMS data sets; 2) engine performance curve trend monitoring and updating; and 3) automated ETF calculation. The algorithm is coded in MATLAB (The MathWorks, Inc.) and currently runs on a PC. Results from the application of this technique to HUMS mission data collected from UH-60L aircraft equipped with T700-GE-701C engines are presented and compared to manually calculated ETF values. Potential future enhancements are discussed.

  7. Transport of engineered silver (Ag) nanoparticles through partially fractured sandstones

    NASA Astrophysics Data System (ADS)

    Neukum, Christoph; Braun, Anika; Azzam, Rafig

    2014-08-01

    Transport behavior and fate of engineered silver nanoparticles (AgNP) in the subsurface is of major interest concerning soil and groundwater protection in order to avoid groundwater contamination of vital resources. Sandstone aquifers are important groundwater resources which are frequently used for public water supply in many regions of the world. The objective of this study is to get a better understanding of AgNP transport behavior in partially fractured sandstones. We executed AgNP transport studies on partially fissured sandstone drilling cores in laboratory experiments. The AgNP concentration and AgNP size in the effluent were analyzed using flow field-flow fractionation mainly. We employed inverse mathematical models on the measured AgNP breakthrough curves to identify and quantify relevant transport processes. Physicochemical filtration, time-dependent blocking due to filling of favorable attachment sites and colloid-facilitated transport were identified as the major processes for AgNP mobility. Physicochemical filtration was found to depend on solute chemistry, mineralogy, pore size distribution and probably on physical and chemical heterogeneity. Compared to AgNP transport in undisturbed sandstone matrix reported in the literature, their mobility in partially fissured sandstone is enhanced probably due to larger void spaces and higher hydraulic conductivity.

  8. Engineered nanoparticles induce cell apoptosis: potential for cancer therapy

    PubMed Central

    Ma, Dan-Dan; Yang, Wan-Xi

    2016-01-01

    Engineered nanoparticles (ENPs) have been widely applied in industry, commodities, biology and medicine recently. The potential for many related threats to human health has been highlighted. ENPs with their sizes no larger than 100 nm are able to enter the human body and accumulate in organs such as brain, liver, lung, testes, etc, and cause toxic effects. Many references have studied ENP effects on the cells of different organs with related cell apoptosis noted. Understanding such pathways towards ENP induced apoptosis may aid in the design of effective cancer targeting ENP drugs. Such ENPs can either have a direct effect towards cancer cell apoptosis or can be used as drug delivery agents. Characteristics of ENPs, such as sizes, shape, forms, charges and surface modifications are all seen to play a role in determining their toxicity in target cells. Specific modifications of such characteristics can be applied to reduce ENP bioactivity and thus alleviate unwanted cytotoxicity, without affecting the intended function. This provides an opportunity to design ENPs with minimum toxicity to non-targeted cells. PMID:27056889

  9. Endocytosis of Nanomedicines: The Case of Glycopeptide Engineered PLGA Nanoparticles

    PubMed Central

    Vilella, Antonietta; Ruozi, Barbara; Belletti, Daniela; Pederzoli, Francesca; Galliani, Marianna; Semeghini, Valentina; Forni, Flavio; Zoli, Michele; Vandelli, Maria Angela; Tosi, Giovanni

    2015-01-01

    The success of nanomedicine as a new strategy for drug delivery and targeting prompted the interest in developing approaches toward basic and clinical neuroscience. Despite enormous advances on brain research, central nervous system (CNS) disorders remain the world’s leading cause of disability, in part due to the inability of the majority of drugs to reach the brain parenchyma. Many attempts to use nanomedicines as CNS drug delivery systems (DDS) were made; among the various non-invasive approaches, nanoparticulate carriers and, particularly, polymeric nanoparticles (NPs) seem to be the most interesting strategies. In particular, the ability of poly-lactide-co-glycolide NPs (PLGA-NPs) specifically engineered with a glycopeptide (g7), conferring to NPs’ ability to cross the blood brain barrier (BBB) in rodents at a concentration of up to 10% of the injected dose, was demonstrated in previous studies using different routes of administrations. Most of the evidence on NP uptake mechanisms reported in the literature about intracellular pathways and processes of cell entry is based on in vitro studies. Therefore, beside the particular attention devoted to increasing the knowledge of the rate of in vivo BBB crossing of nanocarriers, the subsequent exocytosis in the brain compartments, their fate and trafficking in the brain surely represent major topics in this field. PMID:26102358

  10. Ecotoxicity of engineered nanoparticles to aquatic invertebrates: a brief review and recommendations for future toxicity testing.

    PubMed

    Baun, A; Hartmann, N B; Grieger, K; Kusk, K O

    2008-07-01

    Based on a literature review and an overview of toxic effects of engineered nanoparticles in aquatic invertebrates, this paper proposes a number of recommendations for the developing field of nanoecotoxicology by highlighting the importance of invertebrates as sensitive and relevant test organisms. Results show that there is a pronounced lack of data in this field (less than 20 peer-reviewed papers are published so far), and the most frequently tested engineered nanoparticles in invertebrate tests are C(60), carbon nanotubes, and titanium dioxide. In addition, the majority of the studies have used Daphnia magna as the test organism. To date, the limited number of studies has indicated acute toxicity in the low mg l(-1) range and higher of engineered nanoparticles to aquatic invertebrates, although some indications of chronic toxicity and behavioral changes have also been described at concentrations in the high microg l(-1) range. Nanoparticles have also been found to act as contaminant carriers of co-existing contaminants and this interaction has altered the toxicity of specific chemicals towards D. magna. We recommend that invertebrate testing is used to advance the level of knowledge in nanoecotoxicology through standardized short-term (lethality) tests with invertebrates as a basis for investigating behaviour and bioavailability of engineered nanoparticles in the aquatic environment. Based on this literature review, we further recommend that research is directed towards invertebrate tests employing long-term low exposure with chronic endpoints along with more research in bioaccumulation of engineered nanoparticles in aquatic invertebrates.

  11. Metal nanoparticles in diesel exhaust derived by in-cylinder melting of detached engine fragments

    NASA Astrophysics Data System (ADS)

    Liati, Anthi; Pandurangi, Sushant Sunil; Boulouchos, Konstantinos; Schreiber, Daniel; Arroyo Rojas Dasilva, Yadira

    2015-01-01

    A wide range of environmental and health effects are linked to combustion-generated pollutants related to traffic. Nanoparticles, in particular, are a major concern for humans since they can be inhaled and have potentially toxic effects. The variability and sources of combustion-related nanoparticle pollutants remain inadequately investigated. Here we report the presence of ca. 5-100 nm large Fe3O4 nanoparticles, in form of agglomerates, in diesel exhaust. The mode of occurrence of these nanoparticles, in combination with their chemical composition matching that of steel indicate that they derive by melting of engine fragments in the combustion chamber and subsequent crystallization during cooling. To evaluate this hypothesis, we applied CFD simulations of material transport in the cylinder of a diesel engine, assuming detachment of steel fragments from various sites of the cylinder. The CFD results show that fragments ≤20 μm in size dislodged from the piston surface or from the fuel nozzle interior can be indeed transported to such hot areas of the combustion chamber where they can melt. The simulation results concur with the experimental observations and point out that metal nanoparticle formation by in-cylinder melting of engine fragments can occur in diesel engines. The present study proposes a hitherto neglected formation mechanism of metal nanoparticle emissions from internal combustion engines raising possible environmental and health concerns, especially in urban areas.

  12. Impact of engineered zinc oxide nanoparticles on the energy budgets of Mytilus galloprovincialis

    NASA Astrophysics Data System (ADS)

    Muller, Erik B.; Hanna, Shannon K.; Lenihan, Hunter S.; Miller, Robert J.; Nisbet, Roger M.

    2014-11-01

    This paper characterizes the sublethal impact of engineered ZnO nanoparticles on the individual performance of the marine mussel Mytilus galloprovincialis within the context of Dynamic Energy Budget theory, thereby allowing an integrated evaluation of the impact of multiple stressors on various endpoints. Data include measurements of the impact of ZnO nanoparticles on body burden, feeding, respiration, shell length, biomass, and mortality of mussels kept in laboratory tanks for over 100 days. ZnO nanoparticles in the environment impair the mussels' feeding rate (EC50 for the maximum feeding rate is 1.5 mg ZnO nanoparticles L- 1). Zn accumulated in tissue increases respiration (EC50 for the respiration rate is 0.9 mg environmental ZnO nanoparticles L- 1 with the body burden having reached its ultimate level), indicating that maintenance processes are more affected by ZnO nanoparticles than feeding. The feeding regime constrained growth and biomass production to the extent that the impact of ZnO nanoparticles on these processes was undetectable, yet the remaining measurements allowed the estimation of the toxicity parameters. The toxicity representation, combined with the DEB model, allowed the calculation of the effect of the nanoparticles on the expected lifetime production of reproductive matter. EC50 for the expected lifetime production of reproductive matter is less than 0.25 mg ZnO nanoparticles L- 1, indicating that that the ecological impact of ZnO nanoparticle exposure is stronger than its impact on individual physiological rates.

  13. Characterization of nanoparticles released during construction of photocatalytic pavements using engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Dylla, Heather; Hassan, Marwa M.

    2012-03-01

    With the increasing use of titanium dioxide (TiO2) nanoparticles in self-cleaning materials such as photocatalytic concrete pavements, the release of nanoparticles into the environment is inevitable. Nanoparticle concentration, particle size, surface area, elemental composition, and surface morphology are pertinent to determine the associated risks. In this study, the potential of exposure to synthetic nanoparticles released during construction activities for application of photocatalytic pavements was measured during laboratory-simulated construction activities of photocatalytic mortar overlays and in an actual field application of photocatalytic spray coat. A scanning mobility particle sizer system measured the size distribution of nanoparticles released during laboratory and field activities. Since incidental nanoparticles are released during construction activities, nanoparticle emissions were compared to those from similar activities without nano-TiO2. Nanoparticle counts and size distribution suggest that synthetic nanoparticles are released during application of photocatalytic pavements. In order to identify the nanoparticle source, nanoparticles were also collected for offline characterization using transmission electron microscopy. However, positive identification of synthetic nanoparticles was not possible due to difficulties in obtaining high-resolution images. As a result, further research is recommended to identify nanoparticle composition and sources.

  14. Dysregulation of Macrophage Activation Profiles by Engineered Nanoparticles

    PubMed Central

    Kodali, Vamsi; Littke, Matthew H.; Tilton, Susan C.; Teeguarden, Justin G.; Shi, Liang; Frevert, Charles W.; Wang, Wei; Pounds, Joel G.; Thrall, Brian D.

    2013-01-01

    Although the potential human health impacts from exposure to engineered nanoparticles (ENPs) are uncertain, past epidemiological studies have established correlations between exposure to ambient air pollution particulates and the incidence of pneumonia and lung infections. Using amorphous silica and superparamagnetic iron oxide (SPIO) as model high production volume ENPs, we examined how macrophage activation by bacterial lipopolysaccharide (LPS) or the lung pathogen Streptococcus pneumoniae is altered by ENP pre-treatment. Neither silica nor SPIO treatment elicited direct cytotoxic or pro-inflammatory effects in bone marrow-derived macrophages. However, pre-treatment of macrophages with SPIO caused extensive reprogramming of nearly 500 genes regulated in response to LPS challenge, hallmarked by exaggerated activation of oxidative stress response pathways and suppressed activation of both pro- and anti-inflammatory pathways. Silica pre-treatment altered regulation of only 67 genes, but there was strong correlation with gene sets affected by SPIO. Macrophages exposed to SPIO displayed a phenotype suggesting an impaired ability to transition from a M1 to M2-like activation state, characterized by suppressed IL-10 induction, enhanced TNFα production, and diminished phagocytic activity toward S. pneumoniae. Studies in macrophages deficient in scavenger receptor A (SR-A) showed SR-A participates in cell uptake of both the ENPs and S. pneumonia, and co-regulates the anti-inflammatory IL-10 pathway. Thus, mechanisms for dysregulation of innate immunity exist by virtue that common receptor recognition pathways are used by some ENPs and pathogenic bacteria, although the extent of transcriptional reprogramming of macrophage function depends on the physicochemical properties of the ENP after internalization. Our results also illustrate that biological effects of ENPs may be indirectly manifested only after challenging normal cell function. Nanotoxicology screening strategies

  15. Dysregulation of Macrophage Activation Profiles by Engineered Nanoparticles

    SciTech Connect

    Kodali, Vamsi; Littke, Matthew H.; Tilton, Susan C.; Teeguarden, Justin G.; Shi, Liang; Frevert, Charles W.; Wang, Wei; Pounds, Joel G.; Thrall, Brian D.

    2013-08-27

    Although the potential human health impacts from exposure to engineered nanoparticles (ENPs) are uncertain, past epidemiological studies have established correlations between exposure to ambient air pollution particulates and the incidence of pneumonia and lung infections. Using amorphous silica and superparamagnetic iron oxide (SPIO) as model high production volume ENPs, we examined how macrophage activation by bacterial lipopolysaccharide (LPS) or the lung pathogen Streptococcus pneumoniae is altered by ENP pretreatment. Neither silica nor SPIO treatment elicited direct cytotoxic or pro-inflammatory effects in bone marrow-derived macrophages. However, pretreatment of macrophages with SPIO caused extensive reprogramming of nearly 500 genes regulated in response to LPS challenge, hallmarked by exaggerated activation of oxidative stress response pathways and suppressed activation of both pro- and anti-inflammatory pathways. Silica pretreatment altered regulation of only 67 genes, but there was strong correlation with gene sets affected by SPIO. Macrophages exposed to SPIO displayed a phenotype suggesting an impaired ability to transition from an M1 to M2-like activation state, characterized by suppressed IL-10 induction, enhanced TNFα production, and diminished phagocytic activity toward S. pneumoniae. Studies in macrophages deficient in scavenger receptor A (SR-A) showed SR-A participates in cell uptake of both the ENPs and S. pneumonia and co-regulates the anti-inflammatory IL-10 pathway. Thus, mechanisms for dysregulation of innate immunity exist by virtue that common receptor recognition pathways are used by some ENPs and pathogenic bacteria, although the extent of transcriptional reprogramming of macrophage function depends on the physicochemical properties of the ENP after internalization. Our results also illustrate that biological effects of ENPs may be indirectly manifested only after challenging normal cell function. Finally, nanotoxicology screening

  16. Assembly of surface engineered nanoparticles for functional materials

    NASA Astrophysics Data System (ADS)

    Yu, Xi

    Nanoparticles are regarded as exciting new building blocks for functional materials due to their fascinating physical properties because of the nano-confinement. Organizing nanoparticles into ordered hierarchical structures are highly desired for constructing novel optical and electrical artificial materials that are different from their isolated state or thermodynamics random ensembles. My research integrates the surface chemistry of nanoparticles, interfacial assembly and lithography techniques to construct nanoparticle based functional structures. We designed and synthesized tailor-made ligands for gold, semiconductor and magnetic nanoparticle, to modulate the assembly process and collective properties of the assembled structures, by controlling the key parameters such as particle-interface interaction, dielectric environments and inter-particle coupling etc. Top-down technologies such as micro contact printing, photolithography and nanoimprint lithography are used to guide the assembly into arbitrarily predesigned structures for potential device applications.

  17. The effects of surface aging on nanoparticle fate and transport in natural and engineered porous media

    NASA Astrophysics Data System (ADS)

    Mittelman, Anjuliee M.

    Nanomaterials will be subjected to various surface transformations in the environment and within water and wastewater treatment systems. A comprehensive understanding of the fate and transport behavior of "aged" nanomaterials in both natural and engineered porous media is required in order to accurately quantify ecological and human health risks. This research sought to (1) evaluate the impact of ultraviolet (UV) light aging on nanoparticle transport in water-saturated porous media; and (2) assess the effects of influent water quality on silver nanoparticle retention and dissolution in ceramic water filters. Additionally, the value of quartz crystal microbalance (QCM-D) data in nanoparticle fate and transport studies was evaluated by comparing deposition behavior in complementary QCM-D and sand columns experiments. Silver (nAg) and iron oxide nanoparticles exposed to UV light were up to 50% more strongly retained in porous media compared with freshly prepared suspensions due to less negative surface charge and larger aggregate sizes. UV-aged nAg were more prone to dissolution in sand columns, resulting in effluent Ag+ concentrations as high as 1.2 mg/L. In ceramic water filters, dissolution and cation exchange processes controlled silver release into treated water. The use of acidic, high salinity, or high hardness water accelerated oxidative dissolution of the silver coating and resulted in effluent silver concentrations 5-10 times above international drinking water guidelines. Results support the recommendation for a regular filter replacement or silver re-application schedule to ensure ongoing efficacy. Taken in concert, these research findings suggest that oxidative aging of nanomaterial surfaces (either through exposure to UV light or aggressive water chemistries) will alter the fate of nanomaterials in the environment and may decrease the effective lifetime of devices which utilize nanotechnology. Corresponding QCM-D and column experiments revealed that

  18. Engineered metal nanoparticles in the sub-nanomolar levels kill cancer cells

    PubMed Central

    Vodyanoy, Vitaly; Daniels, Yasmine; Pustovyy, Oleg; MacCrehan, William A; Muramoto, Shin; Stan, Gheorghe

    2016-01-01

    Background Small metal nanoparticles obtained from animal blood were observed to be toxic to cultured cancer cells, whereas noncancerous cells were much less affected. In this work, engineered zinc and copper metal nanoparticles were produced from bulk metal rods by an underwater high-voltage discharge method. The metal nanoparticles were characterized by atomic force microscopy and X-ray photoelectron spectroscopy. The metal nanoparticles, with estimated diameters of 1 nm–2 nm, were determined to be more than 85% nonoxidized. A cell viability assay and high-resolution light microscopy showed that exposure of RG2, cultured rat brain glioma cancer cells, to the zinc and copper nanoparticles resulted in cell morphological changes, including decreased cell adherence, shrinking/rounding, nuclear condensation, and budding from cell bodies. The metal-induced cell injuries were similar to the effects of staurosporine, an active apoptotic reagent. The viability experiments conducted for zinc and copper yielded values of dissociation constants of 0.22±0.08 nmol/L (standard error [SE]) and 0.12±0.02 nmol/L (SE), respectively. The noncancerous astrocytes were not affected at the same conditions. Because metal nanoparticles were lethal to the cancer cells at sub-nanomolar concentrations, they are potentially important as nanomedicine. Purpose Lethal concentrations of synthetic metal nanoparticles reported in the literature are a few orders of magnitude higher than the natural, blood-isolated metal nanoparticles; therefore, in this work, engineered metal nanoparticles were examined to mimic the properties of endogenous metal nanoparticles. Materials and methods RG2, rat brain glioma cells CTX TNA2 brain rat astrocytes, obtained from the American Type Culture Collection, high-voltage discharge, atomic force microscope, X-ray photoelectron spectroscopy, high-resolution light microscopy, zeta potential measurements, and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium

  19. Engineering the Structure and Properties of DNA-Nanoparticle Superstructures Using Polyvalent Counterions.

    PubMed

    Chou, Leo Y T; Song, Fayi; Chan, Warren C W

    2016-04-06

    DNA assembly of nanoparticles is a powerful approach to control their properties and prototype new materials. However, the structure and properties of DNA-assembled nanoparticles are labile and sensitive to interactions with counterions, which vary with processing and application environment. Here we show that substituting polyamines in place of elemental counterions significantly enhanced the structural rigidity and plasmonic properties of DNA-assembled metal nanoparticles. These effects arose from the ability of polyamines to condense DNA and cross-link DNA-coated nanoparticles. We further used polyamine wrapped DNA nanostructures as structural templates to seed the growth of polymer multilayers via layer-by-layer assembly, and controlled the degree of DNA condensation, plasmon coupling efficiency, and material responsiveness to environmental stimuli by varying polyelectrolyte composition. These results highlight counterion engineering as a versatile strategy to tailor the properties of DNA-nanoparticle assemblies for various applications, and should be applicable to other classes of DNA nanostructures.

  20. Monitor for detecting and assessing exposure to airborne nanoparticles

    NASA Astrophysics Data System (ADS)

    Marra, Johan; Voetz, Matthias; Kiesling, Heinz-Jürgen

    2010-01-01

    An important safety aspect of the workplace environment concerns the severity of its air pollution with nanoparticles (NP; <100 nm) and ultrafine particles (UFP; <300 nm). Depending on their size and chemical nature, exposure to these particles through inhalation can be hazardous because of their intrinsic ability to deposit in the deep lung regions and the possibility to subsequently pass into the blood stream. Recommended safety measures in the nanomaterials industry are pragmatic, aiming at exposure minimization in general, and advocating continuous control by monitoring both the workplace air pollution level and the personal exposure to airborne NPs. This article describes the design and operation of the Aerasense NP monitor that enables intelligence gathering in particular with respect to airborne particles in the 10-300 nm size range. The NP monitor provides real time information about their number concentration, average size, and surface areas per unit volume of inhaled air that deposit in the various compartments of the respiratory tract. The monitor's functionality relies on electrical charging of airborne particles and subsequent measurements of the total particle charge concentration under various conditions. Information obtained with the NP monitor in a typical workplace environment has been compared with simultaneously recorded data from a Scanning Mobility Particle Sizer (SMPS) capable of measuring the particle size distribution in the 11-1086 nm size range. When the toxicological properties of the engineered and/or released particles in the workplace are known, personal exposure monitoring allows a risk assessment to be made for a worker during each workday, when the workplace-produced particles can be distinguished from other (ambient) particles.

  1. Refinement of the Nanoparticle Emission Assessment Technique into the Nanomaterial Exposure Assessment Technique (NEAT 2.0)

    PubMed Central

    Eastlake, Adrienne C; Beaucham, Catherine; Martinez, Kenneth F; Dahm, Matthew M; Sparks, Christopher; Hodson, Laura L; Geraci, Charles L

    2016-01-01

    Engineered nanomaterial emission and exposure characterization studies have been completed at more than 60 different facilities by the National Institute for Occupational Safety and Health (NIOSH). These experiences have provided NIOSH the opportunity to refine an earlier published technique, the Nanoparticle Emission Assessment Technique (NEAT 1.0), into a more comprehensive technique for assessing worker and workplace exposures to engineered nanomaterials. This change is reflected in the new name Nanomaterial Exposure Assessment Technique (NEAT 2.0) which distinguishes it from NEAT 1.0. NEAT 2.0 places a stronger emphasis on time-integrated, filter-based sampling (i.e., elemental mass analysis and particle morphology) in the worker's breathing zone (full shift and task specific) and area samples to develop job exposure matrices. NEAT 2.0 includes a comprehensive assessment of emissions at processes and job tasks, using direct-reading instruments (i.e., particle counters) in data-logging mode to better understand peak emission periods. Evaluation of worker practices, ventilation efficacy, and other engineering exposure control systems and risk management strategies serve to allow for a comprehensive exposure assessment. PMID:27027845

  2. Engineering assessment of inactive uranium mill tailings

    SciTech Connect

    Not Available

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive.

  3. Using the Power of Organic Synthesis for Engineering the Interactions of Nanoparticles with Biological Systems.

    PubMed

    Mizuhara, Tsukasa; Moyano, Daniel F; Rotello, Vincent M

    2016-02-01

    The surface properties of nanoparticles (NPs) dictate their interaction with the outside world. The use of precisely designed molecular ligands to control NP surface properties provides an important toolkit for modulating their interaction with biological systems, facilitating their use in biomedicine. In this review we will discuss the application of the atom-by-atom control provided by organic synthesis to the generation of engineered nanoparticles, with emphasis on how the functionalization of NPs with these "small" organic molecules (Mw < 1,000) can be used to engineer NPs for a wide range of applications.

  4. Assessing nanoparticle risk poses prodigious challenges

    EPA Science Inventory

    Risk assessment is used both formally and informally to estimate the likelihood of an adverse event occurring, for example, as a consequence of exposure to a hazardous chemical, drug or other agent. Formal risk assessments in government regulatory agencies have a long history of ...

  5. Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES)

    PubMed Central

    Echevarría-Vega, Manuel E.; Sotiriou, Georgios A.; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

    2013-01-01

    Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO2 ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20–46 % points compared to non-coated fabric and could provide collection efficiency above 95 %. PMID:23412707

  6. Modes of interaction between inorganic engineered nanoparticles and biological and abiotic surfaces

    NASA Astrophysics Data System (ADS)

    Schaumann, G. E.; Abraham, P. M.; Dabrunz, A.

    2012-04-01

    Engineered nanoparticles aging and transformation pathways in natural environmental systems are linked with their attachment to surfaces of organisms, plant leaves, biofilms, soil or sediment particles. In this study we investigated attachment of nAg0 and nTiO2 to plant leaves and organic and inorganic model surfaces and daphnia with the objective to understand the physicochemistry behind these interactions as well as potential ecological effects linked with this attachment. Surface-nanoparticle interactions were investigated in well-defined sorption studies and compared to conditions in in ecotoxicological test systems. Model surfaces were chosen to cover a wide range of intermolecular interactions considering van-der Waals interactions as well as proton donor and acceptor interactions. The nanoparticle-surface complexes were analysed with microscopic techniques including optical microscopy, environmental scanning electron microscopy and atomic force microscopy (AFM) as well as with respect to physicochemical interactions. While deposition of nanoparticles in ecotoxicological test systems is often determined by aggregation, and toxicity may be induced by physical effects, sorption of nanoparticle from stable suspensions is controlled by the chemical nature of the model surfaces as well as by the surfaces accessible for the nanoparticles. The current results show that attachment is determined by an intensive interplay between physicochemical nanoparticle-surface interactions, aggregation stability and physical characteristics. This interplay will mutually affect the ecological relevance, including further fate, transport and effects of the nanoparticles in the environment.

  7. Size Matters: Developing Design Rules to Engineer Nanoparticles for Solid Tumour Targeting

    NASA Astrophysics Data System (ADS)

    Sykes, Edward Alexander

    Nanotechnology enables the design of highly customizable platforms for producing minimally invasive and programmable strategies for cancer diagnosis and treatment. Advances in this field have demonstrated that nanoparticles can enhance specificity of anti-cancer agents, respond to tumour-specific cues, and direct the visualization of biological targets in vivo. . Nanoparticles can be synthesized within the 1 to 100 nm range to achieve different electromagnetic properties and specifically interact with biological tissues by tuning their size, shape, and surface chemistry. However, it remains unclear which physicochemical parameters are critical for delivering nanomaterials to the tumour site. With less than 5% of administered nanoparticles reaching the tumour, engineering of nanoparticles for effective delivery to solid tumours remains a critical challenge to cancer nanomedicine. A more comprehensive understanding of the interplay between the nanomaterial physicochemical properties and biological systems is necessary to enhance the efficacy of nanoparticle tumour targeting. This thesis explores how nanoparticle size and functionalization with cancer cell specific agents impact nanoparticle delivery to tumours. Furthermore, this doctoral work (i) discusses how tumour structure evolves with growth, (ii) elucidates how such changes modulate nanoparticle accumulation, and (iii) identifies how the skin serves as a significant off-target site for nanoparticle uptake. This thesis also demonstrates the utility of empirically-derived parametric models, Monte Carlo simulations, and decision matrices for mechanistically understanding and predicting the impact of nanomaterial features and tumour biology on nanoparticle fate in vivo. These topics establish key design considerations to tailor nanoparticles for enhanced tumour targeting. Collectively, the concepts presented herein form a fundamental framework for the development of personalized nanomedicine and nano

  8. Polymer coated gold nanoparticles for tracing the mobility of engineered nanoparticles in the subsurface

    NASA Astrophysics Data System (ADS)

    Uthuppu, Basil; Sidelmann Fjordbøge, Annika; Caspersen, Eva; Broholm, Mette Martina; Havsteen Jakobsen, Mogens

    2014-05-01

    Nanoparticles (NPs) are manufactured for their specific properties providing possibilities for new and improved products and applications. The use of engineered nanoparticles (ENPs) has therefore brought significant innovation and advances to society, including benefits for human health and the environment. At the same time, little is known about the potential risk associated with the inevitable release of these new materials to the environment, and their new properties are poorly understood . Suspensions of ENPs are not very stable, as they tend to aggregate thereby losing their properties as single particles. Coatings, including a large variety of natural and synthetic polymers, are used to enhance the colloid stability in high concentrations . However, increasing the stability of these materials may lead to unintended effects, such as enhancing their mobility in surface water and groundwater leading to inadvertent impacts on aquatic ecosystems and human health. Detection of ENPs in natural water systems, however, has proved very challenging. Hence, there is a need for tracing of ENP behaviour in the environment. We suggest a possibility of introducing inert gold NPs with the same mobility as the reactive NPs, as tracer particles. Colloidal gold has been of great interest for centuries due to its vibrant colors produced by the interaction with visible light. The unusual optical-electronic properties, high chemical stability and relatively low toxicity have made them the model system of choice in this context. Also, the natural occurrence of these particles in the proposed environment is very rare. Laboratory based experiments conducted in sand columns show that stable aqueous suspensions of gold NPs coated with amphiphilic block co polymers (PVP-VA and PVA-COOH) are extremely mobile (retardation factors of 1.0-1.2) with high recovery values (50-95 %). The specific retardation and recovery depends on the coating type, concentration and grafting method. The NPs

  9. [Occupational exposure to nanoparticles. Assessment of workplace exposure].

    PubMed

    Bujak-Pietrek, Stella

    2010-01-01

    Nanotechnology is currently one of the most popular branch of science. It is a technology that enables designing, manufacturing and application of materials and structures of very small dimensions, and its products are applied in almost every field of life. Nanoparticles are the structures having one or more dimensions of the order of 100 nm or less. They are used in precise mechanics, electronics, optics, medicine, pharmacy, cosmetics and many other spheres. Due to their very small size, nanostructures have completely different and specific properties, unknown for the bulk of materials. Fast-growing nanotechnology provides a wide spectrum of applications, but it also brings about new and unknown danger to human health. Nanotechnology is the branch that has developed rather recently, and much information about health risk and its influence on the environment is beyond our knowledge. Nanoparticles, released in many technological processes, as well as manufactured nanoparticles can induce occupational hazards to workers. The lack of regulations and standards, compulsory in the manufacture and use ofnanoparticles is a fundamental problem faced in the evaluation of exposure. Another problem is the choice of proper measurement equipment for surveying of very small particles - their number, mass and surface area in the workpost air. In this article, the possibility and scope of exposure assessment is discussed and a brief specification of available instrumentation for counting and assessing the parameters essential for classifying the exposure to nanoparticles is presented.

  10. Cream formulation impact on topical administration of engineered colloidal nanoparticles.

    PubMed

    Santini, Benedetta; Zanoni, Ivan; Marzi, Roberta; Cigni, Clara; Bedoni, Marzia; Gramatica, Furio; Palugan, Luca; Corsi, Fabio; Granucci, Francesca; Colombo, Miriam

    2015-01-01

    In order to minimize the impact of systemic toxicity of drugs in the treatment of local acute and chronic inflammatory reactions, the achievement of reliable and efficient delivery of therapeutics in/through the skin is highly recommended. While the use of nanoparticles is now an established practice for drug intravenous targeted delivery, their transdermal penetration is still poorly understood and this important administration route remains almost unexplored. In the present study, we have synthesized magnetic (iron oxide) nanoparticles (MNP) coated with an amphiphilic polymer, developed a water-in-oil emulsion formulation for their topical administration and compared the skin penetration routes with the same nanoparticles deposited as a colloidal suspension. Transmission and scanning electron microscopies provided ultrastructural evidence that the amphiphilic nanoparticles (PMNP) cream formulation allowed the efficient penetration through all the skin layers with a controllable kinetics compared to suspension formulation. In addition to the preferential follicular pathway, also the intracellular and intercellular routes were involved. PMNP that crossed all skin layers were quantified by inductively coupled plasma mass spectrometry. The obtained data suggests that combining PMNP amphiphilic character with cream formulation improves the intradermal penetration of nanoparticles. While PMNP administration in living mice via aqueous suspension resulted in preferential nanoparticle capture by phagocytes and migration to draining lymph nodes, cream formulation favored uptake by all the analyzed dermis cell types, including hematopoietic and non-hematopoietic. Unlike aqueous suspension, cream formulation also favored the maintenance of nanoparticles in the dermal architecture avoiding their dispersion and migration to draining lymph nodes via afferent lymphatics.

  11. Cream Formulation Impact on Topical Administration of Engineered Colloidal Nanoparticles

    PubMed Central

    Marzi, Roberta; Cigni, Clara; Bedoni, Marzia; Gramatica, Furio; Palugan, Luca; Corsi, Fabio; Granucci, Francesca; Colombo, Miriam

    2015-01-01

    In order to minimize the impact of systemic toxicity of drugs in the treatment of local acute and chronic inflammatory reactions, the achievement of reliable and efficient delivery of therapeutics in/through the skin is highly recommended. While the use of nanoparticles is now an established practice for drug intravenous targeted delivery, their transdermal penetration is still poorly understood and this important administration route remains almost unexplored. In the present study, we have synthesized magnetic (iron oxide) nanoparticles (MNP) coated with an amphiphilic polymer, developed a water-in-oil emulsion formulation for their topical administration and compared the skin penetration routes with the same nanoparticles deposited as a colloidal suspension. Transmission and scanning electron microscopies provided ultrastructural evidence that the amphiphilic nanoparticles (PMNP) cream formulation allowed the efficient penetration through all the skin layers with a controllable kinetics compared to suspension formulation. In addition to the preferential follicular pathway, also the intracellular and intercellular routes were involved. PMNP that crossed all skin layers were quantified by inductively coupled plasma mass spectrometry. The obtained data suggests that combining PMNP amphiphilic character with cream formulation improves the intradermal penetration of nanoparticles. While PMNP administration in living mice via aqueous suspension resulted in preferential nanoparticle capture by phagocytes and migration to draining lymph nodes, cream formulation favored uptake by all the analyzed dermis cell types, including hematopoietic and non-hematopoietic. Unlike aqueous suspension, cream formulation also favored the maintenance of nanoparticles in the dermal architecture avoiding their dispersion and migration to draining lymph nodes via afferent lymphatics. PMID:25962161

  12. Toxicity assessment of zero valent iron nanoparticles on Artemia salina.

    PubMed

    Kumar, Deepak; Roy, Rajdeep; Parashar, Abhinav; Raichur, Ashok M; Chandrasekaran, Natarajan; Mukherjee, Anita; Mukherjee, Amitava

    2017-01-19

    The present study deals with the toxicity assessment of two differently synthesized zero valent iron nanoparticles (nZVI, chemical and biological) as well as Fe(2+) ions on Artemia salina at three different initial concentrations of 1, 10, and 100 mg/L of these particles. The assessment was done till 96 h at time intervals of 24 h. EC50 value was calculated to evaluate the 50% mortality of Artemia salina at all exposure time durations. Between chemically and biologically synthesized nZVI nanoparticles, insignificant differences in the level of mortality were demonstrated. At even 24 h, Fe(2+) ion imparted complete lethality at the highest exposure concentration (100 mg/L). To understand intracellular oxidative stress because of zero valent iron nanoparticles, ROS estimation, SOD activity, GSH activity, and catalase activity was performed which demonstrated that ionic form of iron is quite lethal at high concentrations as compared with the same concentration of nZVI exposure. Lower concentrations of nZVI were more toxic as compared with the ionic form and was in order of CS-nZVI > BS-nZVI > Fe(2+) . Cell membrane damage and bio-uptake of nanoparticles were also evaluated for all three concentrations of BS-nZVI, CS-nZVI, and Fe(2+) using adult Artemia salina in marine water; both of which supported the observations made in toxicity assessment. This study can be further explored to exploit Artemia salina as a model organism and a biomarker in an nZVI prone aquatic system to detect toxic levels of these nanoparticles.

  13. Thermogelling chitosan-collagen-bioactive glass nanoparticle hybrids as potential injectable systems for tissue engineering.

    PubMed

    Moreira, Cheisy D F; Carvalho, Sandhra M; Mansur, Herman S; Pereira, Marivalda M

    2016-01-01

    Recently, stimuli-responsive nanocomposite-derived hydrogels have gained prominence in tissue engineering because they can be applied as injectable scaffolds in bone and cartilage repair. Due to the great potential of these systems, this study aimed to synthesize and characterize novel thermosensitive chitosan-based composites, chemically modified with collagen and reinforced by bioactive glass nanoparticles (BG) on the development of injectable nanohybrids for regenerative medicine applications. Thus, the composite hydrogels were extensively characterized by structural, morphological, rheological, and biological testing. The composites showed thermosensitive response with the gelation temperature at approximately 37 °C, which is compatible with the human body temperature. In addition, scanning electron microscopy (SEM) analysis indicated that the chitosan hydrogels exhibited 3D-porous structures, and the incorporation of collagen in the system caused increase on the average pore size. Fourier transform infrared spectroscopy (FTIR) analysis indicated the main functional groups of each component of the composite system and their chemical interactions forming the scaffold. Moreover, rheological measurements were employed to assess the viscoelastic behavior of the hydrogels as a function of the temperature. The results demonstrated that the addition of collagen and bioactive glass increases the mechanical properties after the gelation process. The addition of 2 wt.% of BG nanoparticles caused an increase of approximately 39% on stiffness compared to pure chitosan and the addition of 30 wt.% collagen caused a further increase on the stiffness by 95%. The cytotoxicity and cell viability of the hydrogels were assessed by MTT and LIVE/DEAD® assays, where the results demonstrated no toxic effect of the composites on the human osteosarcoma cell culture (SAOS) and kidney cells line of human embryo (HEK 293 T). Hence, it can be stated that innovative composites were

  14. Engineered nanoparticles in wastewater and wastewater sludge - Evidence and impacts

    SciTech Connect

    Brar, Satinder K.; Verma, Mausam; Tyagi, R.D.; Surampalli, R.Y.

    2010-03-15

    Nanotechnology has widespread application in agricultural, environmental and industrial sectors ranging from fabrication of molecular assemblies to microbial array chips. Despite the booming application of nanotechnology, there have been serious implications which are coming into light in the recent years within different environmental compartments, namely air, water and soil and its likely impact on the human health. Health and environmental effects of common metals and materials are well-known, however, when the metals and materials take the form of nanoparticles - consequential hazards based on shape and size are yet to be explored. The nanoparticles released from different nanomaterials used in our household and industrial commodities find their way through waste disposal routes into the wastewater treatment facilities and end up in wastewater sludge. Further escape of these nanoparticles into the effluent will contaminate the aquatic and soil environment. Hence, an understanding of the presence, behavior and impact of these nanoparticles in wastewater and wastewater sludge is necessary and timely. Despite the lack of sufficient literature, the present review attempts to link various compartmentalization aspects of the nanoparticles, their physical properties and toxicity in wastewater and wastewater sludge through simile drawn from other environmental streams.

  15. 322-R2U2 Engineering Assessment - August 2015

    SciTech Connect

    Abri, M.; Griffin, D.

    2015-08-13

    This Engineering Assessment and Certification of Integrity of retention tank system 322-R2 has been prepared for tank systems that store and neutralizes hazardous waste and have secondary containment. The regulations require that this assessment be completed periodically and certified by an independent, qualified, California-registered professional engineer. Abri Environmental Engineering performed an inspection of the 322-R2 Tank system at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA. Mr. William W. Moore, P.E., conducted this inspection on March 16, 2015. Mr. Moore is a California Registered Civil Engineer, with extensive experience in civil engineering, and hazardous waste management.

  16. Health effects of inhaled engineered and incidental nanoparticles.

    PubMed

    Madl, Amy K; Pinkerton, Kent E

    2009-01-01

    Engineered nanoscale materials provide tremendous promise for technological advancements; however, concerns have been raised about whether research of the possible health risks of these nanomaterials is keeping pace with products going to market. Research on nanomaterials, including carbon nanotubes, semiconductor crystals, and other ultrafine particles (i.e., titanium dioxide, quantum dots, iridium) will be examined to illustrate what is currently known or unknown about how particle characteristics (e.g., size, agglomeration, morphology, solubility, surface chemistry) and exposure/dose metrics (e.g., mass, size, surface area) influence the biological fate and toxicity of inhaled nanosized particles. The fact that nanosized particles (1) have a potentially high efficiency for deposition; (2) target both the upper and lower regions of the respiratory tract; (3) are retained in the lungs for a long period of time, and (4) induce more oxidative stress and cause greater inflammatory effects than their fine-sized equivalents suggest a need to study the impact of these particles on the body. Achieving a better understanding of the dynamics at play between particle physicochemistry, transport patterns, and cellular responses in the lungs and other organs will provide a future basis for establishing predictive measures of toxicity or biocompatibility and a framework for assessing potential human health risks.

  17. Assessment of total efficiency in adiabatic engines

    NASA Astrophysics Data System (ADS)

    Mitianiec, W.

    2016-09-01

    The paper presents influence of ceramic coating in all surfaces of the combustion chamber of SI four-stroke engine on working parameters mainly on heat balance and total efficiency. Three cases of engine were considered: standard without ceramic coating, fully adiabatic combustion chamber and engine with different thickness of ceramic coating. Consideration of adiabatic or semi-adiabatic engine was connected with mathematical modelling of heat transfer from the cylinder gas to the cooling medium. This model takes into account changeable convection coefficient based on the experimental formulas of Woschni, heat conductivity of multi-layer walls and also small effect of radiation in SI engines. The simulation model was elaborated with full heat transfer to the cooling medium and unsteady gas flow in the engine intake and exhaust systems. The computer program taking into account 0D model of engine processes in the cylinder and 1D model of gas flow was elaborated for determination of many basic engine thermodynamic parameters for Suzuki DR-Z400S 400 cc SI engine. The paper presents calculation results of influence of the ceramic coating thickness on indicated pressure, specific fuel consumption, cooling and exhaust heat losses. Next it were presented comparisons of effective power, heat losses in the cooling and exhaust systems, total efficiency in function of engine rotational speed and also comparison of temperature inside the cylinder for standard, semi-adiabatic and full adiabatic engine. On the basis of the achieved results it was found higher total efficiency of adiabatic engines at 2500 rpm from 27% for standard engine to 37% for full adiabatic engine.

  18. Dissolution test for risk assessment of nanoparticles: a pilot study.

    PubMed

    Bove, Pasquale; Malvindi, Maria Ada; Kote, Sachin Sayaji; Bertorelli, Rosalia; Summa, Maria; Sabella, Stefania

    2017-03-09

    Worldwide efforts are currently trying to produce effective risk assessment models for orally ingested nanoparticles. These tests should provide quantitative information on the bioaccessibility and bioavailability of products of biotransformation, such as dissolved ionic species and/or aggregates. In vitro dissolution tests might be useful for nanoparticle risk assessment, because of their potential to quantitatively monitor the changes of specific properties (e.g., dissolution, agglomeration, etc.), which are critical factors linked to bioaccessibility/bioavailability. Unfortunately, the technological advancement of such tools is currently hampered by the complexity and evolving nature of nanoparticle properties that are strongly influenced by the environment and are often difficult to trace in a standardized manner. Hence, the test's success depends on its ability to quantify such properties using standardized experimental conditions to mimic reality as closely as possible. Here we applied an in vitro dissolution test to quantify the dissolution of silver nanoparticles under dynamic conditions, which likely occur in human digestion, providing a clear description of the bioaccessible ionic species (free and matrix bound ions or soluble silver organic or inorganic complexes) occurring during the different digestion phases. We demonstrated the test feasibility using a multi-technique approach and following pre-standardized operational procedures to allow for a comprehensive description of the process as a whole. Moreover, this can favour data reliability for benchmarking. Finally, we showed how the estimated values of the bioaccessible ionic species relate to absorption and excretion parameters, as measured in vivo. The outcomes presented in this work highlight the potential regulatory role of the dissolution test for orally ingested nanoparticles and, although preliminary, experimentally demonstrate the regulatory oriented "read-across" principle.

  19. Recent nanoparticle engineering advances in microalgal cultivation and harvesting processes of biodiesel production: a review.

    PubMed

    Lee, Young-Chul; Lee, Kyubock; Oh, You-Kwan

    2015-05-01

    Among the various steps entailed in the production of biodiesel from microalgae, the efficiency and cost-reduction of the cultivation and harvesting steps remain key obstacles to its practical commercialization. Recently, in order to overcome the technical bottlenecks and limitations with regard to both steps, nanoparticle engineering based on particles' unique physico-chemical and mechanical properties has been extensively applied as a powerful analytical and practical tool. These applications include the enhancement of cell growth and/or pigments by light back-scattering, the induction of intracellular lipid accumulation by nutritional competition and/or stress environment, the improvement of cell separation efficiency and processing time from culture broth, the multiple reuse of magnetic nanoparticle flocculant, and integrated one-pot harvesting/cell-disruption. This review presents and discusses the recent nanoparticle-engineering-based developments in the implementation of practical microalgal cultivation and harvesting processes.

  20. Rational engineering of single-chain polypeptides into protein-only, BBB-targeted nanoparticles.

    PubMed

    Serna, Naroa; Céspedes, María Virtudes; Saccardo, Paolo; Xu, Zhikun; Unzueta, Ugutz; Álamo, Patricia; Pesarrodona, Mireia; Sánchez-Chardi, Alejandro; Roldán, Mónica; Mangues, Ramón; Vázquez, Esther; Villaverde, Antonio; Ferrer-Miralles, Neus

    2016-07-01

    A single chain polypeptide containing the low density lipoprotein receptor (LDLR) ligand Seq-1 with blood-brain barrier (BBB) crossing activity has been successfully modified by conventional genetic engineering to self-assemble into stable protein-only nanoparticles of 30nm. The nanoparticulate presentation dramatically enhances in vitro, LDLR-dependent cell penetrability compared to the parental monomeric version, but the assembled protein does not show any enhanced brain targeting upon systemic administration. While the presentation of protein drugs in form of nanoparticles is in general advantageous regarding correct biodistribution, this principle might not apply to brain targeting that is hampered by particular bio-physical barriers. Irrespective of this fact, which is highly relevant to the nanomedicine of central nervous system, engineering the cationic character of defined protein stretches is revealed here as a promising and generic approach to promote the controlled oligomerization of biologically active protein species as still functional, regular nanoparticles.

  1. Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

    EPA Science Inventory

    CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

  2. Engineering nanofluid electrodes: controlling rheology and electrochemical activity of γ-Fe2O3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Sen, Sujat; Moazzen, Elahe; Aryal, Shankar; Segre, Carlo U.; Timofeeva, Elena V.

    2015-11-01

    Nanofluid electrodes or nanoelectrofuels have significant potential in the field of flow batteries, as at high loadings of solid battery active nanoparticles, their energy density can be orders of magnitude higher than in traditional redox flow battery electrolytes. Nanofluid electrodes must have a manageable viscosity at high particle concentrations (i.e., easily pumpable) and exhibit good electrochemical activity toward charge and discharge reactions. Engineering of such nanofluid electrodes involves development of new and unique approaches to stabilization of nanoparticle suspensions. In this work, we demonstrate a surface modification approach that allows controlling the viscosity of nanofluids at high solid loading, while simultaneously retaining electrochemical activity of the nanoparticles. A scalable single step procedure for the surface grafting of small organic molecules onto iron (III) oxide nanoparticles (γ-Fe2O3, maghemite, 40-150 nm) is demonstrated. Modified iron oxide nanoparticles reported here have 5 wt% of the grafting moiety on the surface, which helps forming stable dispersions with up to 40 wt% of solid loading in alkali aqueous electrolytes with a maximum viscosity of 12 cP at room temperature. The maximum particle concentration achievable in the same electrolyte with pristine nanoparticles is 15 wt%. Electrochemical testing of the pristine and modified nanomaterials in the form of solid-casted electrodes showed a maximum reversible discharge capacity of 280 and 155 mAh/g, respectively, indicating that electrochemical activity of modified nanoparticles is partially suppressed due to the surface grafted moiety.

  3. Transport of CO2 foam stabilized with engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Prigiobbe, V.; Worthen, A. J.; Aroonsri, A.; Huh, C.; Bryant, S. L.

    2014-12-01

    Foam injection into the subsurface is performed to improve gas control mobility for residual oil extraction in, e.g., enhanced oil recovery and contaminated site remediation. Foam improves the gas mobility control as the gas viscosity is increased through its dispersion into a liquid phase. Finer the bubbles the lower the gas apparent viscosity (or foam viscosity) and the better is the sweep efficiency of the residual oil. A chemical surfactant adsorbed at the gas-liquid interface is generally used to maintain an optimal foam texture (number of bubbles for unit volume) however it can be desorbed making the foam coarser. Here, we present an experimental and modeling study on the effect of nanoparticles on foam stability. Nanoparticles are adsorbed onto the bubble interface irreversibly and therefore they are expected to keep the desired texture of the foam for the entire time of its application. In this study, we use silica nanoparticles in conjunction with a surfactant to study the transport behavior of a CO2 foam in a porous medium. Experiments were performed using a glass-bead pack and Boise sandstone with foam quality (fg) 0.1-0.9 until steady-state. Foam flow was described by a mechanistic population balance model coupled with the fractional flow equation and constitutive equations for foam generation and destruction based on lamella division and bubble coalescence mechanisms, respectively. In order to minimize the uncertainty, model parameters were estimated by combining experimental data of pressure gradient during steady-state and transient. Experiments and theory agree very well and the overall results show a significant increase in foam texture and stability when nanoparticles and surfactant are added to a foam flow in a low permeability porous medium. Data from tests with various nanoparticle concentrations (cn) show that gas apparent viscosity changes with fg and cn. But its optimal value does not vary with cn and it is already attained at fg equal to 0

  4. Modelling the transport of engineered metallic nanoparticles in the river Rhine.

    PubMed

    Markus, A A; Parsons, J R; Roex, E W M; de Voogt, P; Laane, R W P M

    2016-03-15

    As engineered nanoparticles of zinc oxide, titanium dioxide and silver, are increasingly used in consumer products, they will most probably enter the natural environment via wastewater, atmospheric deposition and other routes. The aim of this study is to predict the concentrations of these nanoparticles via wastewater emissions in a typical river system by means of a numerical model. The calculations rely on estimates of the use of nanomaterials in consumer products and the removal efficiency in wastewater treatment plants as well as model calculations of the fate and transport of nanoparticles in a riverine system. The river Rhine was chosen for this work as it is one of the major and best studied rivers in Europe. The study gives insight in the concentrations that can be expected and, by comparing the model results with measurements of the total metal concentrations, of the relative contribution of these emerging contaminants. Six scenarios were examined. Two scenarios concerned the total emission: in the first it was assumed that nanoparticles are only released via wastewater (treated or untreated) and in the second it was assumed that in addition nanoparticles can enter the river system via runoff from the application of sludge as a fertilizer. In both cases the assumption was that the nanoparticles enter the river system as free, unattached particles. Four additional scenarios, based on the total emissions from the second scenario, were examined to highlight the consequences of the assumption of free nanoparticles and the uncertainties about the aggregation processes. If all nanoparticles enter as free particles, roughly a third would end up attached to suspended particulate matter due to the aggregation processes nanoparticles are subject to. For the other scenarios the contribution varies from 20 to 45%. Since the Rhine is a fast flowing river, sedimentation is unlikely to occur, except at the floodplains and the lakes in the downstream regions, as in fact

  5. Cutaneous exposure scenarios for engineered nanoparticles used in semiconductor fabrication: a preliminary investigation of workplace surface contamination

    PubMed Central

    Shepard, Michele; Brenner, Sara

    2014-01-01

    Background: Numerous studies are ongoing in the fields of nanotoxicology and exposure science; however, gaps remain in identifying and evaluating potential exposures from skin contact with engineered nanoparticles in occupational settings. Objectives: The aim of this study was to identify potential cutaneous exposure scenarios at a workplace using engineered nanoparticles (alumina, ceria, amorphous silica) and evaluate the presence of these materials on workplace surfaces. Methods: Process review, workplace observations, and preliminary surface sampling were conducted using microvacuum and wipe sample collection methods and transmission electron microscopy with elemental analysis. Results: Exposure scenarios were identified with potential for incidental contact. Nanoparticles of silica or silica and/or alumina agglomerates (or aggregates) were identified in surface samples from work areas where engineered nanoparticles were used or handled. Conclusions: Additional data are needed to evaluate occupational exposures from skin contact with engineered nanoparticles; precautionary measures should be used to minimize potential cutaneous exposures in the workplace. PMID:25000112

  6. In-vitro Cell Exposure Studies for the Assessment of Nanoparticle Toxicity in the Lung - A Dialogue between Aerosol Science and Biology

    SciTech Connect

    Hanns-Rudolf, Paur; Cassee, Flemming R.; Teeguarden, Justin G.; Fissan, Heinz; Diabate, Silvia; Aufderheide, M.; Kreyling, Wolfgang G.; Hanninen, Otto; Kasper, G.; Riediker, Michael; Rothen-Rutishauser, Barbara; Schmid, Otmar

    2011-10-01

    The rapid introduction of engineered nanostructured materials into numerous industrial and consumer products will result in enhanced exposure to engineered nanoparticles. Workplace exposure has been identified as the most likely source of uncontrolled inhalation of engineered aerosolized nanoparticles, but release of engineered nanoparticles may occur at any stage of the lifecycle of consumer products. The dynamic development of new nanomaterials with possibly unknown toxicological effects poses a challenge for the assessment of nanoparticle induced toxicity and safety. In this consensus document from a workshop on in-vitro cell systems for nanotoxicity testing an overview is given of the main issues concerning inhalation exposure to nanoparticles, lung physiology, nanoparticle-related biological mechanisms, in-vitro cell exposure systems for nanoparticles and social aspects of nanotechnology. The workshop participants recognized the large potential of in-vitro cell exposure systems for reliable, high-throughput screening of nanotoxicity. For the investigation of pulmonary nanotoxicity, a strong preference was expressed for air-liquid interface (ALI) cell exposure systems (rather than submerged cell exposure systems) as they closely resemble in-vivo conditions in the lungs and they allow for unaltered and dosimetrically accurate delivery of aerosolized nanoparticles to the cells. The members of the workshop believe that further advances in in-vitro cell exposure studies would be greatly facilitated by a more active role of the aerosol scientists. The technical know-how for developing and running ALI in-vitro exposure systems is available in the aerosol community and at the same time biologists/toxicologists are required for proper assessment of the biological impact of nanoparticles.

  7. Plant Mediated Green Synthesis of CuO Nanoparticles: Comparison of Toxicity of Engineered and Plant Mediated CuO Nanoparticles towards Daphnia magna

    PubMed Central

    Saif, Sadia; Tahir, Arifa; Asim, Tayyaba; Chen, Yongsheng

    2016-01-01

    Research on green production methods for metal oxide nanoparticles (NPs) is growing, with the objective to overcome the potential hazards of these chemicals for a safer environment. In this study, facile, ecofriendly synthesis of copper oxide (CuO) nanoparticles was successfully achieved using aqueous extract of Pterospermum acerifolium leaves. P. acerifolium-fabricated CuO nanoparticles were further characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). Plant-mediated CuO nanoparticles were found to be oval shaped and well dispersed in suspension. XPS confirmed the elemental composition of P. acerifolium-mediated copper nanoparticles as comprised purely of copper and oxygen. DLS measurements and ion release profile showed that P. acerifolium-mediated copper nanoparticles were more stable than the engineered CuO NPs. Copper oxide nanoparticles are used in many applications; therefore, their potential toxicity cannot be ignored. A comparative study was performed to investigate the bio-toxic impacts of plant-synthesized and engineered CuO nanoparticles on water flea Daphnia. Experiments were conducted to investigate the 48-h acute toxicity of engineered CuO NPs and plant-synthesized nanoparticles. Lower EC50 value 0.102 ± 0.019 mg/L was observed for engineered CuO NPs, while 0.69 ± 0.226 mg/L was observed for plant-synthesized CuO NPs. Additionally, ion release from CuO nanoparticles and 48-h accumulation of these nano CuOs in daphnids were also calculated. Our findings thus suggest that the contribution of released ions from nanoparticles and particles/ions accumulation in Daphnia needs to be interpreted with care. PMID:28335333

  8. High-Throughput Screening Platform for Engineered Nanoparticle-Mediated Genotoxicity Using CometChip Technology

    PubMed Central

    2015-01-01

    The likelihood of intentional and unintentional engineered nanoparticle (ENP) exposure has dramatically increased due to the use of nanoenabled products. Indeed, ENPs have been incorporated in many useful products and have enhanced our way of life. However, there are many unanswered questions about the consequences of nanoparticle exposures, in particular, with regard to their potential to damage the genome and thus potentially promote cancer. In this study, we present a high-throughput screening assay based upon the recently developed CometChip technology, which enables evaluation of single-stranded DNA breaks, abasic sites, and alkali-sensitive sites in cells exposed to ENPs. The strategic microfabricated, 96-well design and automated processing improves efficiency, reduces processing time, and suppresses user bias in comparison to the standard comet assay. We evaluated the versatility of this assay by screening five industrially relevant ENP exposures (SiO2, ZnO, Fe2O3, Ag, and CeO2) on both suspension human lymphoblastoid (TK6) and adherent Chinese hamster ovary (H9T3) cell lines. MTT and CyQuant NF assays were employed to assess cellular viability and proliferation after ENP exposure. Exposure to ENPs at a dose range of 5, 10, and 20 μg/mL induced dose-dependent increases in DNA damage and cytotoxicity. Genotoxicity profiles of ZnO > Ag > Fe2O3 > CeO2 > SiO2 in TK6 cells at 4 h and Ag > Fe2O3 > ZnO > CeO2 > SiO2 in H9T3 cells at 24 h were observed. The presented CometChip platform enabled efficient and reliable measurement of ENP-mediated DNA damage, therefore demonstrating the efficacy of this powerful tool in nanogenotoxicity studies. PMID:24617523

  9. A novel paradigm for engineering education: virtual internships with individualized mentoring and assessment of engineering thinking.

    PubMed

    Chesler, Naomi C; Ruis, A R; Collier, Wesley; Swiecki, Zachari; Arastoopour, Golnaz; Williamson Shaffer, David

    2015-02-01

    Engineering virtual internships are a novel paradigm for providing authentic engineering experiences in the first-year curriculum. They are both individualized and accommodate large numbers of students. As we describe in this report, this approach can (a) enable students to solve complex engineering problems in a mentored, collaborative environment; (b) allow educators to assess engineering thinking; and (c) provide an introductory experience that students enjoy and find valuable. Furthermore, engineering virtual internships have been shown to increase students'-and especially women's-interest in and motivation to pursue engineering degrees. When implemented in first-year engineering curricula more broadly, the potential impact of engineering virtual internships on the size and diversity of the engineering workforce could be dramatic.

  10. Curriculum Assessment as a Direct Tool in ABET Outcomes Assessment in a Chemical Engineering Programme

    ERIC Educational Resources Information Center

    Abu-Jdayil, Basim; Al-Attar, Hazim

    2010-01-01

    The chemical engineering programme at the United Arab Emirates University is designed to fulfil the Accreditation Board for Engineering and Technology (ABET) (A-K) EC2000 criteria. The Department of Chemical & Petroleum Engineering has established a well-defined process for outcomes assessment for the chemical engineering programme in order to…

  11. Engineer's Notebook--A Design Assessment Tool

    ERIC Educational Resources Information Center

    Kelley, Todd R.

    2011-01-01

    As technology education continues to consider a move toward an engineering design focus as proposed by various leaders in technology education, it will be necessary to employ new pedagogical approaches. Hill (2006) provided some new perspectives regarding pedagogical approaches for technology education with an engineering design focus. One…

  12. Modelling the Release, Transport and Fate of Engineered Nanoparticles in the Aquatic Environment - A Review.

    PubMed

    Markus, Adriaan A; Parsons, John R; Roex, Erwin W M; de Voogt, Pim; Laane, Remi W P M

    2016-12-28

    Engineered nanoparticles, that is, particles of up to 100 nm in at least one dimension, are used in many consumer products. Their release into the environment as a consequence of their production and use has raised concern about the possible consequences. While they are made of ordinary substances, their size gives them properties that are not manifest in larger particles. It is precisely these properties that make them useful. For instance titanium dioxide nanoparticles are used in transparent sunscreens, because they are large enough to scatter ultraviolet light but too small to scatter visible light.To investigate the occurrence of nanoparticles in the environment we require practical methods to detect their presence and to measure the concentrations as well as adequate modelling techniques. Modelling provides both a complement to the available detection and measurement methods and the means to understand and predict the release, transport and fate of nanoparticles. Many different modelling approaches have been developed, but it is not always clear for what questions regarding nanoparticles in the environment these approaches can be applied. No modelling technique can be used for every possible aspect of the release of nanoparticles into the environment. Hence it is important to understand which technique to apply in what situation. This article provides an overview of the techniques involved with their strengths and weaknesses. Two points need to be stressed here: the modelling of processes like dissolution and the surface activity of nanoparticles, possibly under influence of ultraviolet light, or chemical transformation has so far received relatively little attention. But also the uncertainties surrounding nanoparticles in general-the amount of nanoparticles used in consumer products, what constitutes the appropriate measure of concentration (mass or numbers) and what processes are relevant-should be explicitly considered as part of the modelling.

  13. Engineering the defect state and reducibility of ceria based nanoparticles for improved anti-oxidation performance.

    PubMed

    Wang, Yan-Jie; Dong, Hao; Lyu, Guang-Ming; Zhang, Huai-Yuan; Ke, Jun; Kang, Li-Qun; Teng, Jia-Li; Sun, Ling-Dong; Si, Rui; Zhang, Jing; Liu, Yan-Jun; Zhang, Ya-Wen; Huang, Yun-Hui; Yan, Chun-Hua

    2015-09-07

    Due to their excellent anti-oxidation performance, CeO2 nanoparticles receive wide attention in pharmacological application. Deep understanding of the anti-oxidation mechanism of CeO2 nanoparticles is extremely important to develop potent CeO2 nanomaterials for anti-oxidation application. Here, we report a detailed study on the anti-oxidation process of CeO2 nanoparticles. The valence state and coordination structure of Ce are characterized before and after the addition of H2O2 to understand the anti-oxidation mechanism of CeO2 nanoparticles. Adsorbed peroxide species are detected during the anti-oxidation process, which are responsible for the red-shifted UV-vis absorption spectra of CeO2 nanoparticles. Furthermore, the coordination number of Ce in the first coordination shell slightly increased after the addition of H2O2. On the basis of these experimental results, the reactivity of coordination sites for peroxide species is considered to play a key role in the anti-oxidation performance of CeO2 nanoparticles. Furthermore, we present a robust method to engineer the anti-oxidation performance of CeO2 nanoparticles through the modification of the defect state and reducibility by doping with Gd(3+). Improved anti-oxidation performance is also observed in cell culture, where the biocompatible CeO2-based nanoparticles can protect INS-1 cells from oxidative stress induced by H2O2, suggesting the potential application of CeO2 nanoparticles in the treatment of diabetes.

  14. Biopolymer-Based Nanoparticles for Drug/Gene Delivery and Tissue Engineering

    PubMed Central

    Nitta, Sachiko Kaihara; Numata, Keiji

    2013-01-01

    There has been a great interest in application of nanoparticles as biomaterials for delivery of therapeutic molecules such as drugs and genes, and for tissue engineering. In particular, biopolymers are suitable materials as nanoparticles for clinical application due to their versatile traits, including biocompatibility, biodegradability and low immunogenicity. Biopolymers are polymers that are produced from living organisms, which are classified in three groups: polysaccharides, proteins and nucleic acids. It is important to control particle size, charge, morphology of surface and release rate of loaded molecules to use biopolymer-based nanoparticles as drug/gene delivery carriers. To obtain a nano-carrier for therapeutic purposes, a variety of materials and preparation process has been attempted. This review focuses on fabrication of biocompatible nanoparticles consisting of biopolymers such as protein (silk, collagen, gelatin, β-casein, zein and albumin), protein-mimicked polypeptides and polysaccharides (chitosan, alginate, pullulan, starch and heparin). The effects of the nature of the materials and the fabrication process on the characteristics of the nanoparticles are described. In addition, their application as delivery carriers of therapeutic drugs and genes and biomaterials for tissue engineering are also reviewed. PMID:23344060

  15. CD44-engineered mesoporous silica nanoparticles for overcoming multidrug resistance in breast cancer

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Liu, Ying; Wang, Shouju; Shi, Donghong; Zhou, Xianguang; Wang, Chunyan; Wu, Jiang; Zeng, Zhiyong; Li, Yanjun; Sun, Jing; Wang, Jiandong; Zhang, Longjiang; Teng, Zhaogang; Lu, Guangming

    2015-03-01

    Multidrug resistance is a major impediment for the successful chemotherapy in breast cancer. CD44 is over-expressed in multidrug resistant human breast cancer cells. CD44 monoclonal antibody exhibits anticancer potential by inhibiting proliferation and regulating P-glycoprotein-mediated drug efflux activity in multidrug resistant cells. Thereby, CD44 monoclonal antibody in combination with chemotherapeutic drug might be result in enhancing chemosensitivity and overcoming multidrug resistance. The purpose of this study is to investigate the effects of the CD44 monoclonal antibody functionalized mesoporous silica nanoparticles containing doxorubicin on human breast resistant cancer MCF-7 cells. The data showed that CD44-modified mesoporous silica nanoparticles increased cytotoxicity and enhanced the downregulation of P-glycoprotein in comparison to CD44 antibody. Moreover, CD44-engineered mesoporous silica nanoparticles provided active target, which promoted more cellular uptake of DOX in the resistant cells and more retention of DOX in tumor tissues than unengineered counterpart. Animal studies of the resistant breast cancer xenografts demonstrated that CD44-engineered drug delivery system remarkably induced apoptosis and inhibited the tumor growth. Our results indicated that the CD44-engineered mesoporous silica nanoparticle-based drug delivery system offers an effective approach to overcome multidrug resistance in human breast cancer.

  16. Learning theories and assessment methodologies - an engineering educational perspective

    NASA Astrophysics Data System (ADS)

    Hassan, O. A. B.

    2011-08-01

    This paper attempts to critically review theories of learning from the perspective of engineering education in order to align relevant assessment methods with each respective learning theory, considering theoretical aspects and practical observations and reflections. The role of formative assessment, taxonomies, peer learning and educational policy as regards promoting the learning of engineering is discussed. It is suggested that an integrated learning method in which cognitive levels, social factors and teamwork and behaviouristic elements are integrated will optimise the learning process on an engineering course. Moreover, assessment of learning should not be isolated from views of teaching and the learning methods employed by the university teacher.

  17. Risks from accidental exposures to engineered nanoparticles and neurological health effects: A critical review

    PubMed Central

    2010-01-01

    There are certain concerns regarding the safety for the environment and human health from the use of engineered nanoparticles (ENPs) which leads to unintended exposures, as opposed to the use of ENPs for medical purposes. This review focuses on the unintended human exposure of ENPs. In particular, possible effects in the brain are discussed and an attempt to assess risks is performed. Animal experiments have shown that investigated ENPs (metallic nanoparticles, quantum dots, carbon nanotubes) can translocate to the brain from different entry points (skin, blood, respiratory pathways). After inhalation or instillation into parts of the respiratory tract a very small fraction of the inhaled or instilled ENPs reaches the blood and subsequently secondary organs, including the CNS, at a low translocation rate. Experimental in vivo and in vitro studies have shown that several types of ENPs can have various biological effects in the nervous system. Some of these effects could also imply that ENPs can cause hazards, both acutely and in the long term. The relevance of these data for risk assessment is far from clear. There are at present very few data on exposure of the general public to either acute high dose exposure or on chronic exposure to low levels of air-borne ENPs. It is furthermore unlikely that acute high dose exposures would occur. The risk from such exposures for damaging CNS effects is thus probably very low, irrespective of any biological hazard associated with ENPs. The situation is more complicated regarding chronic exposures, at low doses. The long term accumulation of ENPs can not be excluded. However, we do not have exposure data for the general public regarding ENPs. Although translocation to the brain via respiratory organs and the circulation appears to be very low, there remains a possibility that chronic exposures, and/or biopersistent ENPs, can influence processes within the brain that are triggering or aggravating pathological processes. In

  18. Applying accelerator mass spectrometry for low-level detection of complex engineered nanoparticles in biological media.

    PubMed

    Wang, Binghui; Jackson, George S; Yokel, Robert A; Grulke, Eric A

    2014-08-01

    Complex engineered nanoparticles (CENPs), which have different core and surface components, are being developed for medicinal, pharmaceutical and industrial applications. One of the key challenges for environmental health and safety assessments of CENPs is to identify and quantity their transformations in biological environments. This study reports the effects of in vivo exposure of citrate-coated nanoalumina with different rare isotope labels on each component. This CENP was dosed to the rat and accelerator mass spectrometry (AMS) was used to quantify (26)Al, (14)C, and their ratio in the dosing material and tissue samples. For CENPs detected in the liver, the rare isotope ratio, (14)C/(26)Al, was 87% of the dosing material's ratio. The citrate coating on the nanoalumina in the liver was stable or, if it degraded, its metabolites were incorporated with nearby tissues. However, in brain and bone where little alumina was detected, the rare isotope ratio greatly exceeded that of the dosing material. Therefore, in the animal, citrate dissociated from CENPs and redistributed to brain and bone. Tracking both the core and surface components by AMS presents a new approach for characterizing transformations of CENPs components in biological milieu or environments.

  19. Life-cycle assessment of engineered nanomaterials: a literature review of assessment status

    NASA Astrophysics Data System (ADS)

    Miseljic, Mirko; Olsen, Stig I.

    2014-06-01

    The potential environmental impacts of engineered nanomaterials (ENMs), and their engineered nanoparticles (ENPs), have, in recent years, been a cause of concern. Life-cycle assessment (LCA) is a highly qualified tool to assess products and systems and has an increasing extent been applied to ENMs. However, still only 29 case studies on LCA of ENMs have been published in journals and this article investigates these studies. Generally, data on production of ENMs as well as the coverage of the life cycle are limited. In particular, within use and disposal stages data are scarce due to many unknowns regarding the potential release and fate of ENMs/ENPs to and in the environment. This study investigates the sensitivity of case studies with respect to ecotoxicity impacts through a quantification of the potential ecotoxicity impacts to algae, daphnia and fish as a result of direct release of Ag and TiO2 ENPs (mainly <200 nm in nominal diameter size) from various ENM products to the freshwater compartment. It was found that Ag and TiO2 release, from 1 g Ag or TiO2 ENM product, poses up to ca. 3.5 orders of magnitude higher ecotoxicity impact than the production of 1 g polymer (PP, PE and PET average) or 1 Wh of grid mix electricity from Scandinavia. ENMs from Ag had higher ecotoxic impact than those from TiO2 and there was a linear regression between Ag ENM content in the considered products and the potential ecotoxicity impacts to the freshwater species, according to release of total Ag during use (mainly washing).

  20. Engineered PRINT® nanoparticles for controlled delivery of antigens and immunostimulants

    PubMed Central

    Beletskii, Anton; Galloway, Ashley; Rele, Shyam; Stone, Michele; Malinoski, Frank

    2014-01-01

    Particle replication in non-wetting templates (PRINT) is a novel nanoparticle platform that provides compositional flexibility with the ability to specify size and shape in formulating vaccines. The PRINT platform also offers manufacturing and cost advantages over traditional particle technologies. Across multiple antigen and adjuvant formulations, robust antibody and cellular responses have been achieved using PRINT particles in mouse models. Preclinical studies applying PRINT technology in the disease areas of influenza, malaria, and pneumonia are described in this commentary. The proof of principle studies pave the way toward significant cost-effective solutions to global vaccine supply needs. PMID:25424798

  1. Assessment of toxic potential of primary and secondary particulates/aerosols from biodiesel vis-à-vis mineral diesel fuelled engine.

    PubMed

    Agarwal, Avinash Kumar; Gupta, Tarun; Dixit, Neelabh; Shukla, Pravesh Chandra

    2013-05-01

    Toxicity of engine out emissions from primary and secondary aerosols has been a major cause of concern for human health and environmental impact. This study aims to evaluate comparative toxicity of nanoparticles emitted from a modern common rail direct injection engine (CRDI) fuelled with biodiesel blend (B20) vis-à-vis mineral diesel. The toxicity and potential health hazards of exhaust particles were assessed using various parameters such as nanoparticle size and number distribution, surface area distribution, elemental and organic carbon content and polycyclic aromatic hydrocarbons adsorbed onto the particle surfaces, followed by toxic equivalent factor assessment. It was found that biodiesel particulate toxicity was considerably lower in comparison to mineral diesel.

  2. Optimization of nanoparticle focusing by coupling thermophoresis and engineered vortex in a microfluidic channel

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Cao, Zhibo; Fraser, John; Oztekin, Alparslan; Cheng, Xuanhong

    2017-01-01

    Enriching nanoparticles in an aqueous solution is commonly practiced for various applications. Despite recent advances in microfluidic technologies, a general method to concentrate nanoparticles in a microfluidic channel in a label free and continuous flow fashion is not yet available, due to strong Brownian motion on the nanoscale. Recent research of thermophoresis indicates that thermophoretic force can overcome the Brownian force to direct nanoparticle movement. Coupling thermophoresis with natural convection on the microscale has been shown to induce significant enrichment of biomolecules in a thermal diffusion column. However, the column operates in a batch process, and the concentrated samples are inconvenient to retrieve. We have recently designed a microfluidic device that combines a helical fluid motion and simple one-dimensional temperature gradient to achieve effective nanoparticle focusing in a continuous flow. The helical convection is introduced by microgrooves patterned on the channel floor, which directly controls the focusing speed and power. Here, COMSOL simulations are conducted to study how the device geometry and flow rate influence transport and subsequent nanoparticle focusing, with a constant temperature gradient. The results demonstrate a complex dependence of nanoparticle accumulation on the microgroove tilting angle, depth, and spacing, as well as channel width and flow rate. Further dimensional analyses reveal that the ratio between particle velocities induced by thermophoretic and fluid inertial forces governs the particle concentration factor, with a maximum concentration at a ratio of approximately one. This simple relationship provides fundamental insights about nanoparticle transport in coupled flow and thermal fields. The study also offers a useful guideline to the design and operation of nanoparticle concentrators based on combining engineered helical fluid motion subject to phoretic fields.

  3. Specific Internalisation of Gold Nanoparticles into Engineered Porous Protein Cages via Affinity Binding

    PubMed Central

    Peng, Tao; Free, Paul; Fernig, David G.; Lim, Sierin; Tomczak, Nikodem

    2016-01-01

    Porous protein cages are supramolecular protein self-assemblies presenting pores that allow the access of surrounding molecules and ions into their core in order to store and transport them in biological environments. Protein cages’ pores are attractive channels for the internalisation of inorganic nanoparticles and an alternative for the preparation of hybrid bioinspired nanoparticles. However, strategies based on nanoparticle transport through the pores are largely unexplored, due to the difficulty of tailoring nanoparticles that have diameters commensurate with the pores size and simultaneously displaying specific affinity to the cages’ core and low non-specific binding to the cages’ outer surface. We evaluated the specific internalisation of single small gold nanoparticles, 3.9 nm in diameter, into porous protein cages via affinity binding. The E2 protein cage derived from the Geobacillus stearothermophilus presents 12 pores, 6 nm in diameter, and an empty core of 13 nm in diameter. We engineered the E2 protein by site-directed mutagenesis with oligohistidine sequences exposing them into the cage’s core. Dynamic light scattering and electron microscopy analysis show that the structures of E2 protein cages mutated with bis- or penta-histidine sequences are well conserved. The surface of the gold nanoparticles was passivated with a self-assembled monolayer made of a mixture of short peptidols and thiolated alkane ethylene glycol ligands. Such monolayers are found to provide thin coatings preventing non-specific binding to proteins. Further functionalisation of the peptide coated gold nanoparticles with Ni2+ nitrilotriacetic moieties enabled the specific binding to oligohistidine tagged cages. The internalisation via affinity binding was evaluated by electron microscopy analysis. From the various mutations tested, only the penta-histidine mutated E2 protein cage showed repeatable and stable internalisation. The present work overcomes the limitations of

  4. Evaluation of Current Assessment Methods in Engineering Entrepreneurship Education

    ERIC Educational Resources Information Center

    Purzer, Senay; Fila, Nicholas; Nataraja, Kavin

    2016-01-01

    Quality assessment is an essential component of education that allows educators to support student learning and improve educational programs. The purpose of this study is to evaluate the current state of assessment in engineering entrepreneurship education. We identified 52 assessment instruments covered in 29 journal articles and conference…

  5. New Approaches to Cognitive Assessment in Engineering Education.

    ERIC Educational Resources Information Center

    Reeves, Thomas C.; And Others

    This paper describes the development, implementation, and effects of new approaches to cognitive assessment within an undergraduate engineering course at the U.S. Air Force Academy. The course, ENGR 110, "Introduction to Engineering," was designed to be a problem-based learning environment in which cadets worked in teams to solve…

  6. Heteroaggregation of engineered nanoparticles and kaolin clays in aqueous environments.

    PubMed

    Wang, Hongtao; Dong, Ya-nan; Zhu, Miao; Li, Xiang; Keller, Arturo A; Wang, Tao; Li, Fengting

    2015-09-01

    The increasing and wide use of nanoparticles (NPs), including TiO2 and Ag NPs, have raised concerns due to their potential toxicity and environmental impacts. Kaolin is a very common mineral in aquatic systems, and there is a very high probability that nanoparticles (NPs) will interact with these clay minerals. We studied the effect of kaolin particles on the aggregation of NPs under different conditions, including the role of pH, ionic strength (IS), and humic acid (HA). We show that kaolin reduces the energy barrier and the Critical Coagulation Concentration (CCC) at pH 4. At pH 8, even though the energy barrier of the system without kaolin increases, kaolin promotes NP aggregation via heteroaggregation. When IS is equal to or greater than the CCC, on the one hand HA promotes aggregation of TiO2 NPs, but on the other hand HA decreases the rate of Ag NP aggregation because the existence of a surface coating may limit the adsorption of HA on these Ag NPs. In addition, the presence of HA increases the energy barrier and the CCC of the binary system (kaolin + NPs). Thus, the complex interactions of clay, NPs, IS, pH, and HA concentration determine the colloidal stability of the NPs. We find that kaolin is a potential coagulant for removal of NPs that behave like Ag and TiO2.

  7. Engineering Hydrophobic Organosilica Nanoparticle-Doped Nanofibers for Enhanced and Fouling Resistant Membrane Distillation.

    PubMed

    Hammami, Mohammed Amen; Croissant, Jonas G; Francis, Lijo; Alsaiari, Shahad K; Anjum, Dalaver H; Ghaffour, Noreddine; Khashab, Niveen M

    2017-01-18

    Engineering and scaling-up new materials for better water desalination are imperative to find alternative fresh water sources to meet future demands. Herein, the fabrication of hydrophobic poly(ether imide) composite nanofiber membranes doped with novel ethylene-pentafluorophenylene-based periodic mesoporous organosilica nanoparticles is reported for enhanced and fouling resistant membrane distillation. Novel organosilica nanoparticles were homogeneously incorporated into electrospun nanofiber membranes depicting a proportional increase of hydrophobicity to the particle contents. Direct contact membrane distillation experiments on the organosilica-doped membrane with only 5% doping showed an increase of flux of 140% compared to commercial membranes. The high porosity of organosilica nanoparticles was further utilized to load the eugenol antimicrobial agent which produced a dramatic enhancement of the antibiofouling properties of the membrane of 70% after 24 h.

  8. Engineering Undergraduate Distance Learning Programs: An Assessment.

    ERIC Educational Resources Information Center

    Kunnath, Maria Lorna; Eaglin, Ronald

    Distance education reverses the traditional way of providing education to the learning community. Instead of students coming to the university to get that needed education, the university comes to the student. This research/survey of undergraduate engineering distance learning universities was conducted utilizing traditional and virtual sources of…

  9. Combining exposure and effect modeling into an integrated probabilistic environmental risk assessment for nanoparticles.

    PubMed

    Jacobs, Rianne; Meesters, Johannes A J; Ter Braak, Cajo J F; van de Meent, Dik; van der Voet, Hilko

    2016-12-01

    There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To deal with uncertainty in the risk assessment effectively, probabilistic methods are advantageous. In the present study, the authors developed a method to model both the variability and the uncertainty in environmental risk assessment of ENPs. This method is based on the concentration ratio and the ratio of the exposure concentration to the critical effect concentration, both considered to be random. In this method, variability and uncertainty are modeled separately so as to allow the user to see which part of the total variation in the concentration ratio is attributable to uncertainty and which part is attributable to variability. The authors illustrate the use of the method with a simplified aquatic risk assessment of nano-titanium dioxide. The authors' method allows a more transparent risk assessment and can also direct further environmental and toxicological research to the areas in which it is most needed. Environ Toxicol Chem 2016;35:2958-2967. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

  10. Engineering Gd-loaded nanoparticles to enhance MRI sensitivity via T1 shortening

    PubMed Central

    Bruckman, Michael A.; Yu, Xin; Steinmetz, Nicole F.

    2013-01-01

    Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining high-resolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity (R1), leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging. PMID:24158750

  11. Coiled fiber scaffolds embedded with gold nanoparticles improve the performance of engineered cardiac tissues

    NASA Astrophysics Data System (ADS)

    Fleischer, Sharon; Shevach, Michal; Feiner, Ron; Dvir, Tal

    2014-07-01

    Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold.Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00300d

  12. Ligand engineering of lead chalcogenide nanoparticle solar cells

    NASA Astrophysics Data System (ADS)

    Voros, Marton; Brawand, Nicholas; Galli, Giulia

    Semiconductor nanoparticles (NP) are promising materials to build cheap and efficient solar cells. One of the key challenges in their utilization for solar energy conversion is the control of ligand-NP interfaces. Recent experiments have shown that by carefully choosing the ligands terminating the NPs, one can tailor electronic and optical absorption properties of NP assemblies, along with their transport properties. By using density functional theory based methods, we investigated how the opto-electronic properties of lead chalcogenide NPs may be tuned by using diverse organic and inorganic ligands. We interpreted experiments, and we showed that an essential prerequisite to avoid detrimental trap states is to ensure charge balance at the ligand-NP interface, possibly with the help of hydrogen treatment. Work supported by the Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

  13. Harnessing structure-activity relationship to engineer a cisplatin nanoparticle for enhanced antitumor efficacy.

    PubMed

    Paraskar, Abhimanyu S; Soni, Shivani; Chin, Kenneth T; Chaudhuri, Padmaparna; Muto, Katherine W; Berkowitz, Julia; Handlogten, Michael W; Alves, Nathan J; Bilgicer, Basar; Dinulescu, Daniela M; Mashelkar, Raghunath A; Sengupta, Shiladitya

    2010-07-13

    Cisplatin is a first line chemotherapy for most types of cancer. However, its use is dose-limited due to severe nephrotoxicity. Here we report the rational engineering of a novel nanoplatinate inspired by the mechanisms underlying cisplatin bioactivation. We engineered a novel polymer, glucosamine-functionalized polyisobutylene-maleic acid, where platinum (Pt) can be complexed to the monomeric units using a monocarboxylato and an O --> Pt coordinate bond. We show that at a unique platinum to polymer ratio, this complex self-assembles into a nanoparticle, which releases cisplatin in a pH-dependent manner. The nanoparticles are rapidly internalized into the endolysosomal compartment of cancer cells, and exhibit an IC50 (4.25 +/- 0.16 microM) comparable to that of free cisplatin (3.87 +/- 0.37 microM), and superior to carboplatin (14.75 +/- 0.38 microM). The nanoparticles exhibited significantly improved antitumor efficacy in terms of tumor growth delay in breast and lung cancers and tumor regression in a K-ras(LSL/+)/Pten(fl/fl) ovarian cancer model. Furthermore, the nanoparticle treatment resulted in reduced systemic and nephrotoxicity, validated by decreased biodistribution of platinum to the kidney as quantified using inductively coupled plasma spectroscopy. Given the universal need for a better platinate, we anticipate this coupling of nanotechnology and structure-activity relationship to rationally reengineer cisplatin could have a major impact globally in the clinical treatment of cancer.

  14. Engineered magnetic hybrid nanoparticles with enhanced relaxivity for tumor imaging.

    PubMed

    Aryal, Santosh; Key, Jaehong; Stigliano, Cinzia; Ananta, Jeyarama S; Zhong, Meng; Decuzzi, Paolo

    2013-10-01

    Clinically used contrast agents for magnetic resonance imaging (MRI) suffer by the lack of specificity; short circulation time; and insufficient relaxivity. Here, a one-step combinatorial approach is described for the synthesis of magnetic lipid-polymer (hybrid) nanoparticles (MHNPs) encapsulating 5 nm ultra-small super-paramagnetic iron oxide particles (USPIOs) and decorated with Gd(3+) ions. The MHNPs comprise a hydrophobic poly(lactic acid-co-glycolic acid) (PLGA) core, containing up to ~5% USPIOs (w/w), stabilized by lipid and polyethylene glycol (PEG). Gd(3+) ions are directly chelated to the external lipid monolayer. Three different nanoparticle configurations are presented including Gd(3+) chelates only (Gd-MHNPs); USPIOs only (Fe-MHNPs); and the combination thereof (MHNPs). All three MHNPs exhibit a hydrodynamic diameter of about 150 nm. The Gd-MHNPs present a longitudinal relaxivity (r1 = 12.95 ± 0.53 (mM s)(-1)) about four times larger than conventional Gd-based contrast agents (r1 = 3.4 (mM s)(-1)); MHNPs have a transversal relaxivity of r2 = 164.07 ± 7.0 (mM s)(-1), which is three to four times larger than most conventional systems (r2 ~ 50 (mM s)(-1)). In melanoma bearing mice, elemental analysis for Gd shows about 3% of the injected MHNPs accumulating in the tumor and 2% still circulating in the blood, at 24 h post-injection. In a clinical 3T MRI scanner, MHNPs provide significant contrast confirming the observed tumor deposition. This approach can also accommodate the co-loading of hydrophobic therapeutic compounds in the MHNP core, paving the way for theranostic systems.

  15. Engineering Systems Thinking: Definition, Assessing and Correlation with Project Success

    DTIC Science & Technology

    2011-05-01

    Engineering  Systems   Thinking :  Definition, Assessing and Correlation with  Project Success Moti Frank – HIT, Holon Institute of Technology, Israel...00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Engineering Systems Thinking : Definition, Assessing and Correlation with Project Success 5a...b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Engineering  Systems   Thinking : •Definition

  16. Potent engineered PLGA nanoparticles by virtue of exceptionally high chemotherapeutic loadings.

    PubMed

    Enlow, Elizabeth M; Luft, J Christopher; Napier, Mary E; DeSimone, Joseph M

    2011-02-09

    Herein we report the fabrication of engineered poly(lactic acid-co-glycolic acid) nanoparticles via the PRINT (particle replication in nonwetting templates) process with high and efficient loadings of docetaxel, up to 40% (w/w) with encapsulation efficiencies >90%. The PRINT process enables independent control of particle properties leading to a higher degree of tailorability than traditional methods. Particles with 40% loading display better in vitro efficacy than particles with lower loadings and the clinical formulation of docetaxel, Taxotere.

  17. Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications.

    PubMed

    Wu, Wei; Jiang, Chang Zhong; Roy, Vellaisamy A L

    2016-12-01

    Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

  18. Knocking at the door of the unborn child: engineered nanoparticles at the human placental barrier.

    PubMed

    Buerki-Thurnherr, Tina; von Mandach, Ursula; Wick, Peter

    2012-04-05

    Exposure of pregnant women and their unborn children to engineered nanoparticles (NPs) is not yet of major public concern. However, this may soon change in light of the ever-increasing production of NPs and the continuous appearance of novel NP-containing consumer products. However, NPs may not only pose risks to exposed individuals; they offer major potential for the development of novel therapeutic strategies to treat specifically either the mother or the developing foetus. Hence there is every reason to explore the transplacental transfer of engineered NPs in more detail, and to find answers to the vast number of open questions in this fascinating field of research.

  19. Development of screening assays for nanoparticle toxicity assessment in human blood: preliminary studies with charged Au nanoparticles.

    PubMed

    Love, Sara A; Thompson, John W; Haynes, Christy L

    2012-09-01

    As nanoparticles have found increased use in both consumer and medical applications, corresponding increases in possible exposure to humans necessitate studies examining the impacts of these nanomaterials in biological systems. This article examines the effects of approximately 30-nm-diameter gold nanoparticles, with positively and negatively charged surface coatings in human blood. Here, we study the exposure effects, with up to 72 h of exposure to 5, 15, 25 and 50 µg/ml nanoparticles on hemolysis, reactive oxygen species (ROS) generation and platelet aggregation in subsets of cells from human blood. Assessing viability with hemolysis, results show significant changes in a concentration-dependent fashion. Rates of ROS generation were investigated using the dichlorofluorscein diacetate-based assay as ROS generation is a commonly suspected mechanism of nanoparticle toxicity; herein, ROS was not a significant factor. Optical monitoring of platelet aggregation revealed that none of the examined nanoparticles induced aggregation upon short-term exposure.

  20. Development of environmental fate models for engineered nanoparticles--a case study of TiO2 nanoparticles in the Rhine River.

    PubMed

    Praetorius, Antonia; Scheringer, Martin; Hungerbühler, Konrad

    2012-06-19

    For a proactive risk assessment of engineered nanoparticles (ENPs) it is imperative to derive predicted environmental concentration (PEC) values for ENPs in different environmental compartments; PECs can then be compared to effect thresholds. From the basis of established multimedia environmental fate models for organic pollutants, we develop a new concept of environmental fate modeling for ENPs with process descriptions based on the specific properties of ENPs. Our new fate modeling framework is highly flexible and can be adjusted to different ENPs and various environmental settings. As a first case study, the fate and transport of TiO(2) NPs in the Rhine River is investigated. Predicted TiO(2) NP concentrations lie in the ng/L range in the water compartment and mg/kg in the sediment, which represents the main reservoir for the nanoparticles. We also find that a significant downstream transport of ENPs is possible. A fundamental process, the heteroaggregation between TiO(2) NPs and suspended particulate matter (SPM), is analyzed in more detail. Our modeling results demonstrate the importance of both the SPM properties (concentration, size, density) as well as the affinity of TiO(2) NPs and SPM, characterized by the attachment efficiency, α(het-agg), on the transport potential of ENPs in a surface water system.

  1. Vehicle engines produce exhaust nanoparticles even when not fueled.

    PubMed

    Rönkkö, Topi; Pirjola, Liisa; Ntziachristos, Leonidas; Heikkilä, Juha; Karjalainen, Panu; Hillamo, Risto; Keskinen, Jorma

    2014-01-01

    Vehicle engines produce submicrometer exhaust particles affecting air quality, especially in urban environments. In on-road exhaust studies with a heavy duty diesel vehicle and in laboratory studies with two gasoline-fueled passenger cars, we found that as much as 20-30% of the number of exhaust particles larger than 3 nm may be formed during engine braking conditions-that is, during decelerations and downhill driving while the engine is not fueled. Particles appeared at size ranges extending even below 7 nm and at high number concentrations. Their small size and nonvolatility, coupled with the observation that these particles contain lube-oil-derived metals zinc, phosphorus, and calcium, are suggestive of health risks at least similar to those of exhaust particles observed before. The particles' characteristics indicate that their emissions can be reduced using exhaust after-treatment devices, although these devices have not been mandated for all relevant vehicle types. Altogether, our findings enhance the understanding of the formation vehicle emissions and allow for improved protection of human health in proximity to traffic.

  2. Occupational dermal exposure to nanoparticles and nano-enabled products: Part 2, exploration of exposure processes and methods of assessment.

    PubMed

    Brouwer, Derk H; Spaan, Suzanne; Roff, Martin; Sleeuwenhoek, Anne; Tuinman, Ilse; Goede, Henk; van Duuren-Stuurman, Birgit; Filon, Francesca Larese; Bello, Dhimiter; Cherrie, John W

    2016-08-01

    Over the past decade, the primary focus of nanotoxicology and nanoenvironmental health and safety efforts has been largely on inhalation exposure to engineered nanomaterials, at the production stage, and much less on considering risks along the life cycle of nano-enabled products. Dermal exposure to nanomaterials and its health impact has been studied to a much lesser extent, and mostly in the context of intentional exposure to nano-enabled products such as in nanomedicine, cosmetics and personal care products. How concerning is dermal exposure to such nanoparticles in the context of occupational exposures? When and how should we measure it? In the first of a series of two papers (Larese Filon et al., 2016), we focused our attention on identifying conditions or situations, i.e. a combination of nanoparticle physico-chemical properties, skin barrier integrity, and occupations with high prevalence of skin disease, which deserve further investigation. This second paper focuses on the broad question of dermal exposure assessment to nanoparticles and attempts to give an overview of the mechanisms of occupational dermal exposure to nanoparticles and nano-enabled products and explores feasibility and adequacy of various methods of quantifying dermal exposure to NOAA. We provide here a conceptual framework for screening, prioritization, and assessment of dermal exposure to NOAA in occupational settings, and integrate it into a proposed framework for risk assessment.

  3. Genetic engineering of bio-nanoparticles for drug delivery: a review.

    PubMed

    Nishimura, Yuya; Ishii, Jun; Ogino, Chiaki; Kondo, Akihiko

    2014-09-01

    Techniques using nanotechnology in the detection and treatment of cancers have made great progress in multidisciplinary fields. The advances in drug delivery systems (DDSs) have been supported mainly by the development of varied nanoparticles (NPs). Although the NPs based on organic and inorganic materials are integral parts in DDSs, bio-nanoparticles containing biopolymer and virus-like particles (VLPs) are attractive biomaterials for DDSs because of their unique features originating in bio-based materials, such as biocompatibility, biodegradability and low immunogenicity. It is notable that these NPs additionally have a great advantage to enable the easy and flexible alteration of their features by genetic engineering approaches. Controlling the sequence and oligomeric process of polypeptide genes permits a variety of choices in type or size of biopolymeric NPs (e.g., elastin-like polypeptide NPs). In contrast, the functional genes are often inserted into the coding sequences for self-assembled proteins to give the VLPs (e.g., hemagglutinating virus of Japan, adeno-associated virus, human immunodeficiency virus-1, simian virus 40 and hepatitis B virus) additional functions. Thus, genetic engineering readily allow alterations of the properties of NPs (e.g., particle shape, size and stability) and grant of new abilities (e.g., cell-specificity and drug loading and release). In this review, we introduce recent advances in bio-nanoparticles from the standpoint of engineering.

  4. Green rust nanoparticle formation, stability and oxidation, and its role in natural and engineered systems

    NASA Astrophysics Data System (ADS)

    Shaw, S.; Benning, L.; Ahmed, I.; Kakonyi, G.; Sumoondur, A.; Terrill, N.

    2009-12-01

    Highly reactive green rust (GR) nanoparticles are believed to play an important role in the geochemistry of water saturated sediments (e.g. hydromorphic soils) and engineered systems where zero-valent iron is used for decontaminating polluted sites (e.g. permeable reactive barriers). The presence of structural Fe2+ within GR and its high specific surface area make it an effective reductant for many inorganic (e.g. Cr, U, Se) and organic substances (e.g. tetrachloroethene (TCE)). These reduction processes can lead to breakdown of organic molecules or the formation of insoluble reduced inorganic phases (e.g., UO2(s)), thus reducing the bioavailability of these toxic compounds. Understanding the formation and geochemical stability of GR is key to assessing its potential role in natural sediments and engineered environments. However, characterizing GR is difficult due to the rapid oxidation (seconds - minutes) of structural Fe2+ in the presence of air. Thus, to obtain detailed information about the mechanism and kinetics of GR formation, stabilisation and oxidative breakdown, novel synchrotron-based methods have been developed which combine in situ and time-resolved X-ray diffraction/scattering (XRD/SAXS) analysis with controlled anaerobic chemical synthesis. This system allowed the simultaneous quantification of several chemical parameters in the aqueous solution (i.e., pH, Eh) with detailed analysis of the changes in the solid phase crystal structure. In conjunction with this X-ray Absorption Spectroscopy (XAS) was used to characterise the speciation of trace elements (i.e. U, Zn and Se) associated with GR as it crystallised and/or transformed. The formation of green rust (Fe2+/Fe3+ > 1.2) from solution occurs via a 3 stage process. The first stage is the nucleation and growth of ferric hydroxysulfate (schwertmannite) nanoparticles (~5 nm). With increasing pH the schwertmannite transforms into nanogoethite particles (< 50 nm). This process is catalyzed by adsorbed Fe

  5. Effect of electrolyte valency, alginate concentration and pH on engineered TiO₂ nanoparticle stability in aqueous solution.

    PubMed

    Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

    2015-12-01

    Agglomeration and disagglomeration processes are expected to play a key role on the fate of engineered nanoparticles in natural aquatic systems. These processes are investigated here in detail by studying first the stability of TiO2 nanoparticles in the presence of monovalent and divalent electrolytes at different pHs (below and above the point of zero charge of TiO2) and discussing the importance of specific divalent cation adsorption with the help of the DLVO theory as well as the importance of the nature of the counterions. Then the impact of one polysaccharide (alginate) on the stability of agglomerates formed under pH and water hardness representative of Lake Geneva environmental conditions is investigated. In these conditions the large TiO2 agglomerates (diameter>1μm) are positively charged due to Ca(2+) and Mg(2+) specific adsorption and alginate, which is negatively charged, adsorbs onto the agglomerate surface. Our results indicate that the presence of alginate at typical natural organic matter concentration (1-10 mg L(-1)) strongly modifies the TiO2 agglomerate (50 mg L(-1)) stability by inducing their partial and rapid disagglomeration. The importance of disagglomeration is found dependent on the alginate concentration with maximum of disagglomeration obtained for alginate concentration ≥8 mg L(-1) and leading to 400 nm fragments. From an environmental point of view partial restabilization of TiO2 agglomerates in the presence of alginate constitutes an important outcome. Disagglomeration will enhance their transport and residence time in aquatic systems which is an important step in the current knowledge on risk assessment associated to engineered nanoparticles.

  6. Portable Nanoparticle-Based Sensors for Food Safety Assessment

    PubMed Central

    Bülbül, Gonca; Hayat, Akhtar; Andreescu, Silvana

    2015-01-01

    The use of nanotechnology-derived products in the development of sensors and analytical measurement methodologies has increased significantly over the past decade. Nano-based sensing approaches include the use of nanoparticles (NPs) and nanostructures to enhance sensitivity and selectivity, design new detection schemes, improve sample preparation and increase portability. This review summarizes recent advancements in the design and development of NP-based sensors for assessing food safety. The most common types of NPs used to fabricate sensors for detection of food contaminants are discussed. Selected examples of NP-based detection schemes with colorimetric and electrochemical detection are provided with focus on sensors for the detection of chemical and biological contaminants including pesticides, heavy metals, bacterial pathogens and natural toxins. Current trends in the development of low-cost portable NP-based technology for rapid assessment of food safety as well as challenges for practical implementation and future research directions are discussed. PMID:26690169

  7. Portable Nanoparticle-Based Sensors for Food Safety Assessment.

    PubMed

    Bülbül, Gonca; Hayat, Akhtar; Andreescu, Silvana

    2015-12-05

    The use of nanotechnology-derived products in the development of sensors and analytical measurement methodologies has increased significantly over the past decade. Nano-based sensing approaches include the use of nanoparticles (NPs) and nanostructures to enhance sensitivity and selectivity, design new detection schemes, improve sample preparation and increase portability. This review summarizes recent advancements in the design and development of NP-based sensors for assessing food safety. The most common types of NPs used to fabricate sensors for detection of food contaminants are discussed. Selected examples of NP-based detection schemes with colorimetric and electrochemical detection are provided with focus on sensors for the detection of chemical and biological contaminants including pesticides, heavy metals, bacterial pathogens and natural toxins. Current trends in the development of low-cost portable NP-based technology for rapid assessment of food safety as well as challenges for practical implementation and future research directions are discussed.

  8. Assessing Full Spectrum BCT Engineer Capability

    DTIC Science & Technology

    2009-06-12

    volcano mine systems, six Mongoose MICLIC trailers, six HMEEs, six DEUCEs, one Bobcat skid steer tractor, four rapidly emplaced bridge systems (REBS), six...provide obstacle reduction capability. The full width plows and Mongoose MICLIC explosive 50 line clearing charges on the ABVs and the mine...rollers, plows, and Mongoose MICLIC systems for lane reduction. The Mobility Support Platoon of the SBCT engineer company has one hundred feet of Medium

  9. Engineered gold nanoparticles for identification of novel ovarian biomarkers

    NASA Astrophysics Data System (ADS)

    Giri, Karuna

    Ovarian cancer is a leading cause of cancer related death among women in the US and worldwide. The disease has a high mortality rate due to limited tools available that can diagnose ovarian cancer at an early stage and the lack of effective treatments for disease free survival at late stages. Identification of proteins specifically expressed/overexpressed in ovarian cancer could lead to identification of novel diagnostic biomarkers and therapeutic targets that improve patient outcomes. In this regard, mass spectrometry is a powerful tool to probe the proteome of a cancer cell. It can aid discovery of proteins important for the pathophysiology of ovarian cancer. These proteins in turn could serve as diagnostic and treatment biomarkers of the disease. However, a limitation of mass spectrometry based proteomic analyses is that the technique lacks sensitivity and is biased against detection of low abundance proteins. With current approaches to biomarker discovery, we may therefore be overlooking candidate proteins that are important for ovarian cancer. This study presents a new approach to enrich low abundance proteins and subsequently detect them with mass spectrometry. Gold nanoparticles (AuNPs) and functionalization of their surfaces provide an excellent opportunity to capture and enrich low abundance proteins. First, the study focused on conducting an extensive investigation of the time evolution of nanoparticle-protein interaction and understanding drivers of protein attachment on nanoparticle surface. The adsorption of proteins to AuNPs was found to be highly dynamic with multiple attachment and detachment events which decreased over time. Initially, electrostatic forces played an important role in protein binding and structurally flexible proteins such as those involved in RNA processing were more likely to bind to AuNPs. More importantly, the feasibility and success of protein enrichment by AuNPs was evaluated. The AuNPs based approach was able to detect

  10. Shape Engineering of Oxide Nanoparticles for Heterogeneous Catalysis.

    PubMed

    Zhou, Yan; Li, Yong; Shen, Wenjie

    2016-05-20

    The fabrication of oxide particles with tunable sizes and shapes at the nanoscale is one of the most crucial issues for the design and development of highly efficient heterogeneous catalysts. The shape of oxide nanoparticles has been demonstrated to affect their catalytic properties remarkably. Tuning the shape of oxide particles allows preferential exposure of specific reactive facets; this can maximize the number of active sites available to the reactants, which can improve the activity and also mediate the reaction route to a specific channel to achieve higher selectivity for a particular chemical reaction. In addition, the shape of the oxide particles affects their interaction with metal particles or clusters, and this involves interfacial strain and charge transfer. Metal particles or clusters dispersed on the reactive or polar facets of the oxide support often provide superior catalytic performance, primarily because of strong metal-support interactions. However, the geometric and electronic features of the metal-oxide interface may change during the course of the reaction, induced by chemisorption of reactive molecules at elevated temperatures, which should be taken into account in proposing a structure-reactivity relationship.

  11. New Bismuth-Substituted Hydroxyapatite Nanoparticles for Bone Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Ciobanu, Gabriela; Bargan, Ana Maria; Luca, Constantin

    2015-11-01

    New bismuth-substituted hydroxyapatite [Ca10- x Bi x (PO4)6(OH)2 where x = 0-2.5] nanoparticles were synthesized by the co-precipitation method from aqueous solutions. The structural properties of the samples were analyzed by scanning electron microscopy coupled with x-ray analysis, x-ray powder diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface area analysis. The results confirm that bismuth ions have been incorporated into the hydroxyapatite lattice. The prepared nanocrystalline powders consisted of hydroxyapatite as single phase with hexagonal structure, crystal sizes smaller than 60 nm and (Bi + Ca)/P atomic ratio of around 1.67. The hydroxyapatite samples doped with Bi have mesoporous textures with pores size of around 2 nm and specific surface area in the range of 12-25 m2/g. The Bi-substituted hydroxyapatite powders are more effective against Gram-negative Escherichia coli bacteria than Gram-positive Staphylococcus aureus bacteria.

  12. Learning Theories and Assessment Methodologies--An Engineering Educational Perspective

    ERIC Educational Resources Information Center

    Hassan, O. A. B.

    2011-01-01

    This paper attempts to critically review theories of learning from the perspective of engineering education in order to align relevant assessment methods with each respective learning theory, considering theoretical aspects and practical observations and reflections. The role of formative assessment, taxonomies, peer learning and educational…

  13. Internalisation of engineered nanoparticles into mammalian cells in vitro: influence of cell type and particle properties

    NASA Astrophysics Data System (ADS)

    Busch, Wibke; Bastian, Susanne; Trahorsch, Ulrike; Iwe, Maria; Kühnel, Dana; Meißner, Tobias; Springer, Armin; Gelinsky, Michael; Richter, Volkmar; Ikonomidou, Chrysanthy; Potthoff, Annegret; Lehmann, Irina; Schirmer, Kristin

    2011-01-01

    Cellular internalisation of industrial engineered nanoparticles is undesired and a reason for concern. Here we investigated and compared the ability of seven different mammalian cell cultures in vitro to incorporate six kinds of engineered nanoparticles, focussing on the role of cell type and particle properties in particle uptake. Uptake was examined using light and electron microscopy coupled with energy dispersive X-ray spectroscopy (EDX) for particle element identification. Flow cytometry was applied for semi-quantitative analyses of particle uptake and for exploring the influence on uptake by the phagocytosis inhibitor Cytochalasin D (CytoD). All particles studied were found to enter each kind of cultured cells. Yet, particles were never found within cell nuclei. The presence of the respective particles within the cells was confirmed by EDX. Live-cell imaging revealed the time-dependent process of internalisation of technical nanoparticles, which was exemplified by tungsten carbide particle uptake into the human skin cells, HaCaT. Particles were found to co-localise with lysosomal structures within the cells. The incorporated nanoparticles changed the cellular granularity, as measured by flow cytometry, already after 3 h of exposure in a particle specific manner. By correlating particle properties with flow cytometry data, only the primary particle size was found to be a weakly influential property for particle uptake. CytoD, an inhibitor of actin filaments and therewith of phagocytosis, significantly inhibited the internalisation of particle uptake in only two of the seven investigated cell cultures. Our study, therefore, supports the notion that nanoparticles can enter mammalian cells quickly and easily, irrespective of the phagocytic ability of the cells.

  14. A comparison of chemical structures of soot precursor nanoparticles from liquid fuel combustion in flames and engine

    NASA Astrophysics Data System (ADS)

    Paul, Bireswar; Datta, Amitava; Datta, Aparna; Saha, Abhijit

    2013-04-01

    A comparative study of the chemical structures of soot precursor nanoparticles from the liquid fuel flame and engine exhaust has been performed in this work to establish an association between the particles from both the sources. Different ex-situ measurement techniques have been used to characterize the nanoparticles in samples collected from the laboratory petrol/air and iso-octane/air flames, as well as from a gasoline engine. The TEM images of the sampled material along with the EDS spectra corroborate the existence of carbonaceous nanoparticles. The nature of the UV absorption and fluorescence spectra of the samples from the iso-octane flame environment further confirms the sampled materials to be soot precursor nanoparticles. The DLS size distribution of the particles shows them to be below 10 nm size. FTIR spectrum of the precursor nanoparticles collected form the non-sooting zone of the flame and that of fully grown soot particles show few similarities and dissimilarities among them. The soot particles are found to be much more aromatized as compared to its precursor nanoparticles. The presence of carbonyl functional group (C=O) at around 1,720 cm-1 has been observed in soot precursor nanoparticles, while such oxygenated functional groups are not prominent in soot structure. The absorption (UV and IR) and fluorescence spectra of the carbonaceous material collected from the gasoline engine exhaust show many resemblances with those of soot precursor nanoparticles from flames. These spectroscopic resemblances of the soot precursor nanoparticles from the flame environment and engine exhaust gives the evidence that the in-cylinder combustion is the source of these particles in the engine exhaust.

  15. Supercritical Fluid Synthesis and Tribological Applications of Silver Nanoparticle-decorated Graphene in Engine Oil Nanofluid.

    PubMed

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-08-04

    Silver nanoparticle-decorated graphene nanocomposites were synthesized by a facile chemical reduction approach with the assistance of supercritical CO2 (ScCO2). The silver nanoparticles with diameters of 2-16 nm are uniformly distributed and firmly anchored on graphene nanosheets. The tribological properties of the as-synthesized nanocomposites as lubricant additives in engine oil were investigated by a four-ball tribometer. The engine oil with 0.06~0.10 wt.% Sc-Ag/GN nanocomposites displays remarkable lubricating performance, superior than the pure engine oil, the engine oil containing zinc dialkyl dithiophosphate (ZDDP), as well as the oil dispersed with the single nanomaterial of graphene oxides (GOs) and nano-Ag particles alone. The remarkable lubricating behaviors of Sc-Ag/GN probably derive from the synergistic interactions of nano-Ag and graphene in the nanocomposite and the action of the formed protective film on the contact balls. The anchored nano-Ag particles on graphene expand the interlamination spaces of graphene nanosheets and can prevent them from restacking during the rubbing process, resulting in the full play of lubricating activity of graphene. The formed protective film on the friction pairs significantly reduces the surface roughness of the sliding balls and hence preventing them from direct interaction during the sliding process.

  16. Supercritical Fluid Synthesis and Tribological Applications of Silver Nanoparticle-decorated Graphene in Engine Oil Nanofluid

    NASA Astrophysics Data System (ADS)

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-08-01

    Silver nanoparticle-decorated graphene nanocomposites were synthesized by a facile chemical reduction approach with the assistance of supercritical CO2 (ScCO2). The silver nanoparticles with diameters of 2–16 nm are uniformly distributed and firmly anchored on graphene nanosheets. The tribological properties of the as-synthesized nanocomposites as lubricant additives in engine oil were investigated by a four-ball tribometer. The engine oil with 0.06~0.10 wt.% Sc-Ag/GN nanocomposites displays remarkable lubricating performance, superior than the pure engine oil, the engine oil containing zinc dialkyl dithiophosphate (ZDDP), as well as the oil dispersed with the single nanomaterial of graphene oxides (GOs) and nano-Ag particles alone. The remarkable lubricating behaviors of Sc-Ag/GN probably derive from the synergistic interactions of nano-Ag and graphene in the nanocomposite and the action of the formed protective film on the contact balls. The anchored nano-Ag particles on graphene expand the interlamination spaces of graphene nanosheets and can prevent them from restacking during the rubbing process, resulting in the full play of lubricating activity of graphene. The formed protective film on the friction pairs significantly reduces the surface roughness of the sliding balls and hence preventing them from direct interaction during the sliding process.

  17. Supercritical Fluid Synthesis and Tribological Applications of Silver Nanoparticle-decorated Graphene in Engine Oil Nanofluid

    PubMed Central

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-01-01

    Silver nanoparticle-decorated graphene nanocomposites were synthesized by a facile chemical reduction approach with the assistance of supercritical CO2 (ScCO2). The silver nanoparticles with diameters of 2–16 nm are uniformly distributed and firmly anchored on graphene nanosheets. The tribological properties of the as-synthesized nanocomposites as lubricant additives in engine oil were investigated by a four-ball tribometer. The engine oil with 0.06~0.10 wt.% Sc-Ag/GN nanocomposites displays remarkable lubricating performance, superior than the pure engine oil, the engine oil containing zinc dialkyl dithiophosphate (ZDDP), as well as the oil dispersed with the single nanomaterial of graphene oxides (GOs) and nano-Ag particles alone. The remarkable lubricating behaviors of Sc-Ag/GN probably derive from the synergistic interactions of nano-Ag and graphene in the nanocomposite and the action of the formed protective film on the contact balls. The anchored nano-Ag particles on graphene expand the interlamination spaces of graphene nanosheets and can prevent them from restacking during the rubbing process, resulting in the full play of lubricating activity of graphene. The formed protective film on the friction pairs significantly reduces the surface roughness of the sliding balls and hence preventing them from direct interaction during the sliding process. PMID:27488733

  18. A review of selected engineered nanoparticles in the atmosphere: sources, transformations, and techniques for sampling and analysis.

    PubMed

    Majestic, Brian J; Erdakos, Garnet B; Lewandowski, Michael; Oliver, Karen D; Willis, Robert D; Kleindienst, Tadeusz E; Bhave, Prakash V

    2010-01-01

    A state-of-the-science review was undertaken to identify and assess sampling and analysis methods to detect and quantify selected nanomaterials (NMs) in the ambient atmosphere. The review is restricted to five types of NMs of interest to the Office of Research and Development Nanomaterial Research Strategy (U.S. Environmental Protection Agency): cerium oxide, titanium dioxide, carbon nanostructures (carbon nanotubes and fullerenes), zero-valent iron, and silver nanoparticles. One purpose was determining the extent to which present-day ultrafine sampling and analysis methods may be sufficient for identifying and possibly quantifying engineered NMs (ENMs) in ambient air. Conventional sampling methods for ultrafines appear to require modifications. For cerium and titanium, background levels from natural sources make measurement of ENMs difficult to quantify. In cases where field studies have been performed, identification from bulk analysis samples have been made. Further development of methods is needed to identify these NMs, especially in specific size fractions of ambient aerosols.

  19. Engineering an Effective Immune Adjuvant by Designed Control of Shape and Crystallinity of Aluminum Oxyhydroxide Nanoparticles

    PubMed Central

    Sun, Bingbing; Ji, Zhaoxia; Liao, Yu-Pei; Wang, Meiying; Wang, Xiang; Dong, Juyao; Chang, Chong Hyun; Li, Ruibin; Zhang, Haiyuan; Nel, André E.; Xia, Tian

    2014-01-01

    Adjuvants based on aluminum salts (Alum) are commonly used in vaccines to boost the immune response against infectious agents. However, the detailed mechanism of how Alum enhances adaptive immunity and exerts its adjuvant immune effect remains unclear. Other than being comprised of micron-sized aggregates that include nanoscale particulates, Alum lacks specific physicochemical properties to explain activation of the innate immune system, including the mechanism by which aluminum-based adjuvants engage the NLRP3 inflammasome and IL-1β production. This is putatively one of the major mechanisms required for an adjuvant effect. Because we know that long aspect ratio nanomaterials trigger the NLRP3 inflammasome, we synthesized a library of aluminum oxyhydroxide (AlOOH) nanorods to determine whether control of the material shape and crystalline properties could be used to quantitatively assess NLRP3 inflammasome activation and linkage of the cellular response to the material’s adjuvant activities in vivo. Using comparison to commercial Alum, we demonstrate that the crystallinity and surface hydroxyl group display of AlOOH nanoparticles quantitatively impact the activation of the NLRP3 inflammasome in human THP-1 myeloid cells or murine bone marrow-derived dendritic cells (BMDCs). Moreover, these in vitro effects were correlated with the immunopotentiation capabilities of the AlOOH nanorods in a murine OVA immunization model. These results demonstrate that shape, crystallinity and hydroxyl content play an important role in NLRP3 inflammasome activation and are therefore useful for quantitative boosting of antigen-specific immune responses. These results show that the engineered design of aluminum-based adjuvants in combination with dendritic cell property-activity analysis can be used to design more potent aluminum-based adjuvants. PMID:24261790

  20. Size-fractionated characterization and quantification of nanoparticle release rates from a consumer spray product containing engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Hagendorfer, Harald; Lorenz, Christiane; Kaegi, Ralf; Sinnet, Brian; Gehrig, Robert; Goetz, Natalie V.; Scheringer, Martin; Ludwig, Christian; Ulrich, Andrea

    2010-09-01

    This study describes methods developed for reliable quantification of size- and element-specific release of engineered nanoparticles (ENP) from consumer spray products. A modified glove box setup was designed to allow controlled spray experiments in a particle-minimized environment. Time dependence of the particle size distribution in a size range of 10-500 nm and ENP release rates were studied using a scanning mobility particle sizer (SMPS). In parallel, the aerosol was transferred to a size-calibrated electrostatic TEM sampler. The deposited particles were investigated using electron microscopy techniques in combination with image processing software. This approach enables the chemical and morphological characterization as well as quantification of released nanoparticles from a spray product. The differentiation of solid ENP from the released nano-sized droplets was achieved by applying a thermo-desorbing unit. After optimization, the setup was applied to investigate different spray situations using both pump and gas propellant spray dispensers for a commercially available water-based nano-silver spray. The pump spray situation showed no measurable nanoparticle release, whereas in the case of the gas spray, a significant release was observed. From the results it can be assumed that the homogeneously distributed ENP from the original dispersion grow in size and change morphology during and after the spray process but still exist as nanometer particles of size <100 nm. Furthermore, it seems that the release of ENP correlates with the generated aerosol droplet size distribution produced by the spray vessel type used. This is the first study presenting results concerning the release of ENP from spray products.

  1. Retaining minorities in engineering: Assessment of a program prototype

    NASA Astrophysics Data System (ADS)

    Good, Jennifer Marie (Phillips)

    Program assessment is an essential part of healthy program development. Assessment should include multiple considerations, dimensions, and outcomes that match the program's objectives. As a newly formed retention program, the Auburn University Minority Engineering Program, designed to help pre-engineering minority students make the transition into their freshman year of university studies, incorporated evaluation and assessment into all three components of the program (the interactive learning laboratory, critical-thinking workshops, and Sunday-evening tutorials) from the program's inception. If students successfully adapted to the university environment and the demands of the pre-engineering course of study, then retention of minority students in the College of Engineering should improve. Data were gathered on the students involved in the various program components. Students who entered the Minority Engineering Program were pre- and posttested on three standardized subtests (critical thinking, mathematics, and science reasoning) of the Collegiate Assessment of Academic Proficiency. The first-quarter grade-point averages of the students were also gathered to compare their grades to freshman students in previous quarters within the College of Engineering. Qualitative data were also gathered on this same group of students. An analysis of the data revealed that student achievement is affected by involvement in the Minority Engineering Program. Specifically, the first quarter grade point averages of students involved in the program exceeded those of their peers in earlier years of study prior to the program's existence. In addition, mathematics and science reasoning scores on standardized tests increased pre- to postintervention. Comments collected in journals and files also demonstrated use of critical-thinking and problem-solving skills employed by the students. Recommendations for alterations of the program were made based on the outcome of the program evaluation

  2. Influence of Cu, TiO2 Nanoparticles and Carbon Nano-Horns on Tribological Properties of Engine Oil.

    PubMed

    Zin, V; Agresti, F; Barison, S; Colla, L; Fabrizio, M

    2015-05-01

    The addition of nanoparticles in lubricating oils recently demonstrated to reduce the coefficient of friction and to increase the load-carrying capability of lubricant in coupled surfaces. In this work, different kinds of nanoparticles were tested as additives to engine oil to improve lubrication: copper and titanium oxide nanoparticles and single walled carbon nanohorns (SWCNHs). Two nanoparticle sizes were also tested in case of copper. The tribological properties of these nanofluids were evaluated by Stribeck tests, in order to compare the effect of nanoparticles on friction coefficient and electric contact resistance in different lubrication regimes. Stribeck curves showed that the coefficient of friction was reduced, compared to raw oil, by the action of Cu nanoparticles having 130 nm diameter, leading to a mean decrease of about 17%, and by SWCNHs, with a mean decrease of about 12%. Conversely, no significant changes were detected in presence of Cu nanoparticles having 50 nm diameter or of TiO2. The suspension viscosity and stability were also tested. Wear tests were also carried out, showing a reduction of wear rate up to nearly 50% for Cu nanoparticles (150 nm diameter) and around 30% for SWCNHs. The measurements showed that nanoparticles having size comparable to the mean roughness of coupled surfaces significantly improved the tribological properties of bare oil. An explanation of nanoparticle action is proposed.

  3. Enhanced and tunable optical quantum efficiencies from plasmon bandwidth engineering in bimetallic CoAg nanoparticles

    NASA Astrophysics Data System (ADS)

    Malasi, A.; Taz, H.; Ehrsam, M.; Goodwin, J.; Garcia, H.; Kalyanaraman, R.

    2016-10-01

    Plasmonic nanoparticles are amongst the most effective ways to resonantly couple optical energy into and out of nanometer sized volumes. However, controlling and/or tuning the transfer of this incident energy to the surrounding near and far field is one of the most interesting challenges in this area. Due to the dielectric properties of metallic silver (Ag), its nanoparticles have amongst the highest radiative quantum efficiencies (η), i.e., the ability to radiatively transfer the incident energy to the surrounding. Here we report the discovery that bimetallic nanoparticles of Ag made with immiscible and plasmonically weak Co metal can show comparable and/or even higher η values. The enhancement is a result of the narrowing of the plasmon bandwidth from these bimetal systems. The phenomenological explanation of this effect based on the dipolar approximation points to the reduction in radiative losses within the Ag nanoparticles when in contact with cobalt. This is also supported by a model of coupling between poor and good conductors based on the surface to volume ratio. This study presents a new type of bandwidth engineering, one based on using bimetal nanostructures, to tune and/or enhance the quality factor and quantum efficiency for near and far-field plasmonic applications.

  4. Engineered nanoparticles and organic matter: a review of the state-of-the-art.

    PubMed

    Grillo, Renato; Rosa, André H; Fraceto, Leonardo F

    2015-01-01

    Growth in the development and production of engineered nanoparticles (ENPs) in recent years has increased the potential for interactions of these nanomaterials with aquatic and terrestrial environments. Carefully designed studies are therefore required in order to understand the fate, transport, stability, and toxicity of nanoparticles. Natural organic matter (NOM), such as the humic substances found in water, sediment, and soil, is one of the substances capable of interacting with ENPs. This review presents the findings of studies of the interaction of ENPs and NOM, and the possible effects on nanoparticle stability and the toxicity of these materials in the environment. In addition, ENPs and NOM are utilized for many different purposes, including the removal of metals and organic compounds from effluents, and the development of new electronic sensors and other devices for the detection of active substances. Discussion is therefore provided of some of the ways in which NOM can be used in the production of nanoparticles. Although there has been an increase in the number of studies in this area, further progress is needed to improve understanding of the dynamic interactions between ENPs and NOM.

  5. Ergonomic assessments of three Idaho National Engineering Laboratory cafeterias

    SciTech Connect

    Ostrom, L.T.; Romero, H.A.; Gilbert, B.G.; Wilhelmsen, C.A.

    1993-01-01

    The Idaho National Engineering Laboratory is a Department of Energy facility that performs a variety of engineering and research projects. EG G Idaho is the prime contractor for the laboratory and, as such, performs the support functions in addition to technical, research, and development functions. As a part of the EG G Idaho Industrial Hygiene Initiative, ergonomic assessments were conducted at three Idaho National Engineering Laboratory Cafeterias. The purposes of the assessments were to determine whether ergonomic problems existed in the work places and, if so, to make recommendations to improve the work place and task designs. The study showed there were ergonomic problems in all three cafeterias assessed. The primary ergonomic stresses observed included wrist and shoulder stress in the dish washing task, postural stress in the dish washing and food preparation tasks, and back stress in the food handling tasks.

  6. Ergonomic assessments of three Idaho National Engineering Laboratory cafeterias

    SciTech Connect

    Ostrom, L.T.; Romero, H.A.; Gilbert, B.G.; Wilhelmsen, C.A.

    1993-05-01

    The Idaho National Engineering Laboratory is a Department of Energy facility that performs a variety of engineering and research projects. EG&G Idaho is the prime contractor for the laboratory and, as such, performs the support functions in addition to technical, research, and development functions. As a part of the EG&G Idaho Industrial Hygiene Initiative, ergonomic assessments were conducted at three Idaho National Engineering Laboratory Cafeterias. The purposes of the assessments were to determine whether ergonomic problems existed in the work places and, if so, to make recommendations to improve the work place and task designs. The study showed there were ergonomic problems in all three cafeterias assessed. The primary ergonomic stresses observed included wrist and shoulder stress in the dish washing task, postural stress in the dish washing and food preparation tasks, and back stress in the food handling tasks.

  7. Potentials of engineered nanoparticles as fertilizers for increasing agronomic productions.

    PubMed

    Liu, Ruiqiang; Lal, Rattan

    2015-05-01

    Development and application of new types of fertilizers using innovative nanotechnology are one of the potentially effective options of significantly enhancing the global agricultural productions needed to meet the future demands of the growing population. Indeed, the review of available literature indicates that some engineered nanomaterials can enhance plant-growth in certain concentration ranges and could be used as nanofertilizers in agriculture to increase agronomic yields of crops and/or minimize environmental pollution. This article summarizes this type of nanomaterials under four categories: macronutrient nanofertilizers, micronutrient nanofertilizers, nutrient-loaded nanofertilizers, and plant-growth-enhancing nanomaterials. Each category is discussed respectively with reference to nanomaterials' chemical composition, particle size, concentrations applied, benefited plant species, plant incubation methods, and plant-growth enhancement aspects and the rates. The importance, research directions, and research requirements of each nanofertilizer category for achieving sustainable agriculture are also specifically examined. Finally, this review suggests that development of N and P macronutrient nanofertilizers is a high research and development priority both for food production and environmental protection.

  8. Chemical analysis of diesel engine nanoparticles using a nano-DMA/thermal desorption particle beam mass spectrometer.

    PubMed

    Tobias, H J; Beving, D E; Ziemann, P J; Sakurai, H; Zuk, M; McMurry, P H; Zarling, D; Waytulonis, R; Kittelson, D B

    2001-06-01

    Diesel engines are known to emit high number concentrations of nanoparticles (diameter < 50 nm), but the physical and chemical mechanisms by which they form are not understood. Information on chemical composition is lacking because the small size, low mass concentration, and potential for contamination of samples obtained by standard techniques make nanoparticles difficult to analyze. A nano-differential mobility analyzer was used to size-select nanoparticles (mass median diameter approximately 25-60 nm) from diesel engine exhaust for subsequent chemical analysis by thermal desorption particle beam mass spectrometry. Mass spectra were used to identify and quantify nanoparticle components, and compound molecular weights and vapor pressures were estimated from calibrated desorption temperatures. Branched alkanes and alkyl-substituted cycloalkanes from unburned fuel and/or lubricating oil appear to contribute most of the diesel nanoparticle mass. The volatility of the organic fraction of the aerosol increases as the engine load decreases and as particle size increases. Sulfuric acid was also detected at estimated concentrations of a few percent of the total nanoparticle mass. The results are consistent with a mechanism of nanoparticle formation involving nucleation of sulfuric acid and water, followed by particle growth by condensation of organic species.

  9. Surface engineering of inorganic nanoparticles for imaging and therapy.

    PubMed

    Nam, Jutaek; Won, Nayoun; Bang, Jiwon; Jin, Ho; Park, Joonhyuck; Jung, Sungwook; Jung, Sanghwa; Park, Youngrong; Kim, Sungjee

    2013-05-01

    Many kinds of inorganic nanoparticles (NPs) including semiconductor, metal, metal oxide, and lanthanide-doped NPs have been developed for imaging and therapy applications. Their unique optical, magnetic, and electronic properties can be tailored by controlling the composition, size, shape, and structure. Interaction of such NPs with cells and/or in vivo compartments is critically determined by the surface properties, and sophisticated control over the NP surface is essential to control their fate in biological environments. We review NP surface coating strategies using the categories of small surface ligand, polymer, and lipid. Use of small ligand molecules has the advantage of maintaining the minimal hydrodynamic (HD) size. Polymers can be advantageous in NP anchoring by combining multiple affinity groups. Encapsulation of NPs in polymers, lipids or surfactants can preserve the as-synthesized NPs. NP surface properties and reaction conditions should be carefully considered to obtain a bioconjugate that maintains the physicochemical properties of NP and functionalities of the conjugated biomolecules. We highlight how the surface properties of NPs impact their interactions with cells and in vivo compartments, especially focused on the important surface design parameters such as HD size, surface charge, and targeting. Typically, maximal cellular uptake can take place in the intermediate NP size range of 40-60nm. Clearance of NPs from blood circulation is largely dependent on the degree of uptake by reticuloendothelial system when they are larger than 10nm. When the HD size is below 10nm, NPs show broad distribution over many organs. Reduction of HD size below the limit of renal barrier can achieve fast clearance of NPs. For maximal tumor accumulation, NPs should have long blood circulation time and should be large enough to prevent rapid penetration. NPs are also desired to rapidly clear out from the body after the mission before they cause toxic side effects

  10. Application of a pilot control banding tool for risk level assessment and control of nanoparticle exposures

    SciTech Connect

    Paik, S Y; Zalk, D M; Swuste, P

    2008-03-03

    Control Banding (CB) strategies offer simplified solutions for controlling worker exposures to constituents that are found in the workplace in the absence of firm toxicological and exposure data. These strategies may be particularly useful in nanotechnology applications, considering the overwhelming level of uncertainty over what nanomaterials and nanotechnologies present as potential work-related health risks, what about these materials might lead to adverse toxicological activity, how risk related to these might be assessed, and how to manage these issues in the absence of this information. This study introduces a pilot CB tool or 'CB Nanotool' that was developed specifically for characterizing the health aspects of working with engineered nanoparticles and determining the level of risk and associated controls for five ongoing nanotechnology-related operations being conducted at two Department of Energy (DOE) research laboratories. Based on the application of the CB Nanotool, four of the five operations evaluated in this study were found to have implemented controls consistent with what was recommended by the CB Nanotool, with one operation even exceeding the required controls for that activity. The one remaining operation was determined to require an upgrade in controls. By developing this dynamic CB Nanotool within the realm of the scientific information available, this application of CB appears to be a useful approach for assessing the risk of nanomaterial operations, providing recommendations for appropriate engineering controls, and facilitating the allocation of resources to the activities that most need them.

  11. Number of Nanoparticles per Cell through a Spectrophotometric Method - A key parameter to Assess Nanoparticle-based Cellular Assays

    PubMed Central

    Unciti-Broceta, Juan D.; Cano-Cortés, Victoria; Altea-Manzano, Patricia; Pernagallo, Salvatore; Díaz-Mochón, Juan J.; Sánchez-Martín, Rosario M.

    2015-01-01

    Engineered nanoparticles (eNPs) for biological and biomedical applications are produced from functionalised nanoparticles (NPs) after undergoing multiple handling steps, giving rise to an inevitable loss of NPs. Herein we present a practical method to quantify nanoparticles (NPs) number per volume in an aqueous suspension using standard spectrophotometers and minute amounts of the suspensions (up to 1 μL). This method allows, for the first time, to analyse cellular uptake by reporting NPs number added per cell, as opposed to current methods which are related to solid content (w/V) of NPs. In analogy to the parameter used in viral infective assays (multiplicity of infection), we propose to name this novel parameter as multiplicity of nanofection. PMID:25976173

  12. Number of Nanoparticles per Cell through a Spectrophotometric Method - A key parameter to Assess Nanoparticle-based Cellular Assays.

    PubMed

    Unciti-Broceta, Juan D; Cano-Cortés, Victoria; Altea-Manzano, Patricia; Pernagallo, Salvatore; Díaz-Mochón, Juan J; Sánchez-Martín, Rosario M

    2015-05-15

    Engineered nanoparticles (eNPs) for biological and biomedical applications are produced from functionalised nanoparticles (NPs) after undergoing multiple handling steps, giving rise to an inevitable loss of NPs. Herein we present a practical method to quantify nanoparticles (NPs) number per volume in an aqueous suspension using standard spectrophotometers and minute amounts of the suspensions (up to 1 μL). This method allows, for the first time, to analyse cellular uptake by reporting NPs number added per cell, as opposed to current methods which are related to solid content (w/V) of NPs. In analogy to the parameter used in viral infective assays (multiplicity of infection), we propose to name this novel parameter as multiplicity of nanofection.

  13. Validation of an LDH Assay for Assessing Nanoparticle Toxicity

    PubMed Central

    Han, Xianglu; Gelein, Robert; Corson, Nancy; Wade-Mercer, Pamela; Jiang, Jingkun; Biswas, Pratim; Finkelstein, Jacob N.; Elder, Alison; Oberdörster, Günter

    2014-01-01

    Studies showed that certain cytotoxicity assays were not suitable for assessing nanoparticle (NP) toxicity. We evaluated a lactate dehydrogenase (LDH) assay for assessing copper (Cu-40, 40 nm), silver (Ag-35, 35 nm; Ag-40, 40 nm), and titanium dioxide (TiO2-25, 25 nm) NPs by examining their potential to inactivate LDH and interference with β-nicotinamide adenine dinucleotide (NADH), a substrate for the assay. We also performed a dissolution assay for some of the NPs. We found that the copper NPs, because of their high dissolution rate, could interfere with the LDH assay by inactivating LDH. Ag-35 could also inactivate LDH probably because of the carbon matrix used to cage the particles during synthesis. TiO2-25 NPs were found to adsorb LDH molecules. In conclusion, NP interference with the LDH assay depends on the type of NPs and the suitability of the assay for assessing NP toxicity should be examined case by case. PMID:21722700

  14. Engineering an artificial amoeba propelled by nanoparticle-triggered actin polymerization

    NASA Astrophysics Data System (ADS)

    Yi, Jinsoo; Schmidt, Jacob; Chien, Aichi; Montemagno, Carlo D.

    2009-02-01

    We have engineered an amoeba system combining nanofabricated inorganic materials with biological components, capable of propelling itself via actin polymerization. The nanofabricated materials have a mechanism similar to the locomotion of the Listeria monocytogenes, food poisoning bacteria. The propulsive force generation utilizes nanoparticles made from nickel and gold functionalized with the Listeria monocytogenes transmembrane protein, ActA. These Listeria-mimic nanoparticles were in concert with actin, actin binding proteins, ATP (adenosine triphosphate) and encapsulated within a lipid vesicle. This system is an artificial cell, such as a vesicle, where artificial nanobacteria and actin polymerization machinery are used in driving force generators inside the cell. The assembled structure was observed to crawl on a glass surface analogously to an amoeba, with the speed of the movement dependent on the amount of actin monomers and ATP present.

  15. Direct surface engineering of silicon nanoparticles prepared by collinear double-pulse ns laser ablation

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Momeni, A.

    2017-01-01

    In this paper we study the photoluminescence properties of colloidal silicon nanoparticles (Si NPs) in distilled water, with the aim of clarifying the role of surface characteristics on the emission properties. We will show that double-pulse ns laser ablation (DPLA) of a silicon target in water with different inter-pulse delay times of i.e. 5 and 10 ns can result in production of colloidal Si NPs with different PL emission intensities at the visible spectral range of 550-650 nm. The results reveal that DPLA process at the different delay times can induce different oxide related surface characteristics on the Si NPs through the direct surface engineering of the nanoparticles. A detailed analysis of the PL emissions using the stochastic quantum confinement model explained that the different emission behaviors of the colloids are associated with the oxide-related surface states which are contributed as radiative centers in the PL process.

  16. The many faces of soot: characterization of soot nanoparticles produced by engines.

    PubMed

    Niessner, Reinhard

    2014-11-10

    Soot nanoparticles produced by engines constitute a threat to human health. For the analytical chemist, soot is a hard nut to crack as the released particles undergo rapid changes in their size, shape, and number concentration. The complete characterization of soot will be essential to meet future low-emission standards. Besides measuring the light extinction, modern analytical chemistry can determine a variety of less-known effects, such as condensation properties, immune response in vertebrates, and impact on the cardiovascular function of a beating heart. Photon emission and in particular Raman spectroscopy provides information on the nanocrystallinity, while thermoelectron emission allows the number of electrical particles to be counted. Even the "simple" combustion of soot nanoparticles offers potential for the characterization of the particles.

  17. Engineering an artificial amoeba propelled by nanoparticle-triggered actin polymerization.

    PubMed

    Yi, Jinsoo; Schmidt, Jacob; Chien, Aichi; Montemagno, Carlo D

    2009-02-25

    We have engineered an amoeba system combining nanofabricated inorganic materials with biological components, capable of propelling itself via actin polymerization. The nanofabricated materials have a mechanism similar to the locomotion of the Listeria monocytogenes, food poisoning bacteria. The propulsive force generation utilizes nanoparticles made from nickel and gold functionalized with the Listeria monocytogenes transmembrane protein, ActA. These Listeria-mimic nanoparticles were in concert with actin, actin binding proteins, ATP (adenosine triphosphate) and encapsulated within a lipid vesicle. This system is an artificial cell, such as a vesicle, where artificial nanobacteria and actin polymerization machinery are used in driving force generators inside the cell. The assembled structure was observed to crawl on a glass surface analogously to an amoeba, with the speed of the movement dependent on the amount of actin monomers and ATP present.

  18. Situated learning methodologies and assessment in civil engineering structures education

    NASA Astrophysics Data System (ADS)

    Bertz, Michael Davis

    This thesis describes an overarching study of civil engineering undergraduate structural education through student performance in recalling and applying basic structural engineering knowledge, and the viability of alternative situated learning environments for more effectively supporting the learning of this knowledge. To properly ground this study, a thorough investigation of related work in assessment, cognitive science, educational technology, and design education was completed, with connections and applications to civil engineering education highlighted. The experimental work of the thesis is organized into three parts: an assessment of civil engineering undergraduates' fundamental structural engineering knowledge and abilities; the development and testing of a software support environment for situated learning, the Civil Engineering Learning Library (CELL); and, the implementation and evaluation of the design studio, a pedagogical model for situated learning in the classroom. The results of the assessment study indicate that civil engineering seniors (and also students earlier in the curriculum) have difficulty retaining and applying basic knowledge of structural behavior, especially doing so in a flexible fashion in design situations. The survey also suggests that visualization plays an important role in understanding structural behavior. Tests with the CELL system show that a cognitively-flexible multimedia environment can support structural learning, but were inconclusive about whether the computer-based system helped the students to learn better than conventional classroom lecture. Two trial implementations of the design studio indicate that the studio model can serve as a powerful situated learning environment, and that it can be scaled up to reasonable class sizes. Significant requirements are associated with this model, however, primarily in faculty involvement, but also in physical resources and student time. In addition to these conclusions about the

  19. Effects of dispersed aggregates of carbon and titanium dioxide engineered nanoparticles on rainbow trout hepatocytes.

    PubMed

    Thomas, Kevin V; Farkas, Julia; Farmen, Eivind; Christian, Paul; Langford, Katherine; Wu, Quinglan; Tollefsen, Knut-Erik

    2011-01-01

    The purpose of this study was to investigate the cytotoxicity and oxidative stress responses of selected engineered carbon and titanium dioxide (TiO2) nanomaterials to rainbow trout (Oncorhynchus mykiss) primary hepatocytes. The engineered nanomaterials tested were C(60) fullerenes, multiwall nanotubes (MWNT), single-wall nanotubes (SWNT) (functionalized and nonfunctionalized), and TiO2 of 5 and 200 nm in size. Characterization of these materials showed that they were typically present in solution as agglomerates. The engineered nanoparticle agglomerates were cytotoxic at nominal concentrations of >3 mg/L, and certain MWNT and SWNT produced significant intracellular reactive oxygen species (ROS) production as well as cytotoxicity. Analyses of the MWNT responsible for ROS production and cytotoxicity for selected transition metals demonstrated the presence of residual cobalt (Co), which was not present in the nonreactive/non-bioactive MWNT. Cobalt alone was not able to induce the observed effects in hepatocyte cells; however, coexposure with MWNT resulted in an increase in cytotoxicity. Data suggest that trace metals often associated with commercial nanotubes are responsible for the observed biological effects. In addition, other mechanisms, such as the proposed facilitated transport (e.g., Trojan horse) type mechanism of uptake, may provoke an increased response compared to aqueous exposures of trace metals in the absence of carbon nanoparticles.

  20. Molecularly imprinted sol-gel nanoparticles for mass-sensitive engine oil degradation sensing.

    PubMed

    Lieberzeit, Peter A; Afzal, Adeel; Glanzing, Gerd; Dickert, Franz L

    2007-09-01

    Titanate sol-gel layers imprinted with midchain carbonic acids have proven highly useful for detecting engine oil degradation processes owing to selective incorporation of oxidised base oil components. Synthesising the material from TiCl(4) in CCl(4) and precipitating with water leads to imprinted TiO(2) nanoparticles with a diameter of 200-300 nm. Replacing the water by a 1 M ammonium hydroxide solution reduces the average particle size to 50-100 nm with retention of the interaction capabilities. Experiments with the latter solution revealed that the 100-nm particles take up substantially more analyte, indicating a size-dependent phenomenon. As the number of interaction sites within each material is the same, this cannot be a consequence of thermodynamics but must be one of accessibility. The sensor characteristic of water-precipitated particles towards engine oil degradation products shows substantially increased sensitivity and dynamic range compared with the corresponding thin films. Coating quartz crystal microbalances with such nanoparticle materials leads to engine oil degradation sensors owing to incorporation of acidic base oil oxidation products. Interaction studies over a large range of layer thicknesses revealed that both the absolute signal and the steepness of the correlation between the sensor signal and the layer height is 2 times higher for the particles.

  1. The applicability of chemical alternatives assessment for engineered nanomaterials.

    PubMed

    Hjorth, Rune; Hansen, Steffen Foss; Jacobs, Molly; Tickner, Joel; Ellenbecker, Michael; Baun, Anders

    2017-01-01

    The use of alternatives assessment to substitute hazardous chemicals with inherently safer options is gaining momentum worldwide as a legislative and corporate strategy to minimize consumer, occupational, and environmental risks. Engineered nanomaterials represent an interesting case for alternatives assessment approaches, because they can be considered both emerging "chemicals" of concern, as well as potentially safer alternatives to hazardous chemicals. However, comparing the hazards of nanomaterials to traditional chemicals or to other nanomaterials is challenging, and critical elements in chemical hazard and exposure assessment may have to be fundamentally altered to sufficiently address nanomaterials. The aim of this paper is to assess the overall applicability of alternatives assessment methods for nanomaterials and to outline recommendations to enhance their use in this context. The present paper focuses on the adaptability of existing hazard and exposure assessment approaches to engineered nanomaterials as well as strategies to design inherently safer nanomaterials. We argue that alternatives assessment for nanomaterials is complicated by the sheer number of nanomaterials possible. As a result, the inclusion of new data tools that can efficiently and effectively evaluate nanomaterials as substitutes is needed to strengthen the alternatives assessment process. However, we conclude that with additional tools to enhance traditional hazard and exposure assessment modules of alternatives assessment, such as the use of mechanistic toxicity screens and control banding tools, alternatives assessment can be adapted to evaluate engineered nanomaterials as potential substitutes for chemicals of concern and to ensure safer nanomaterials are incorporated in the design of new products. Integr Environ Assess Manag 2017;13:177-187. © 2016 SETAC.

  2. Stirling engine - Approach for long-term durability assessment

    NASA Astrophysics Data System (ADS)

    Tong, Michael T.; Bartolotta, Paul A.; Halford, Gary R.; Freed, Alan D.

    The approach employed by NASA Lewis for the long-term durability assessment of the Stirling engine hot-section components is summarized. The approach consists of: preliminary structural assessment; development of a viscoplastic constitutive model to accurately determine material behavior under high-temperature thermomechanical loads; an experimental program to characterize material constants for the viscoplastic constitutive model; finite-element thermal analysis and structural analysis using a viscoplastic constitutive model to obtain stress/strain/temperature at the critical location of the hot-section components for life assessment; and development of a life prediction model applicable for long-term durability assessment at high temperatures. The approach should aid in the provision of long-term structural durability and reliability of Stirling engines.

  3. Engine-Out Capabilities Assessment of Heavy Lift Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Holladay, Jon; Baggett, Keithe; Thrasher, Chad; Bellamy, K. Scott; Feldman, Stuart

    2012-01-01

    Engine-out (EO) is a condition that might occur during flight due to the failure of one or more engines. Protection against this occurrence can be called engine-out capability (EOC) whereupon significantly improved loss of mission may occur, in addition to reduction in performance and increased cost. A standardized engine-out capability has not been studied exhaustively as it pertains to space launch systems. This work presents results for a specific vehicle design with specific engines, but also uniquely provides an approach to realizing the necessity of EOC for any launch vehicle system design. A derived top-level approach to engine-out philosophy for a heavy lift launch vehicle is given herein, based on an historical assessment of launch vehicle capabilities. The methodology itself is not intended to present a best path forward, but instead provides three parameters for assessment of a particular vehicle. Of the several parameters affected by this EOC, the three parameters of interest in this research are reliability (Loss of Mission (LOM) and Loss of Crew (LOC)), vehicle performance, and cost. The intent of this effort is to provide insight into the impacts of EO capability on these parameters. The effects of EOC on reliability, performance and cost are detailed, including how these important launch vehicle metrics can be combined to assess what could be considered overall launch vehicle affordability. In support of achieving the first critical milestone (Mission Concept Review) in the development of the Space Launch System (SLS), a team assessed two-stage, large-diameter vehicles that utilized liquid oxygen (LOX)-RP propellants in the First Stage and LOX/LH2 propellant in the Upper Stage. With multiple large thrust-class engines employed on the stages, engine-out capability could be a significant driver to mission success. It was determined that LOM results improve by a factor of five when assuming EOC for both Core Stage (CS) (first stage) and Upper Stage (US

  4. Environmental Engineering Curricula assessment in the global world

    NASA Astrophysics Data System (ADS)

    Caporali, Enrica; Catelani, Marcantonio; Manfrida, Giampaolo; Valdiserri, Juna

    2014-05-01

    Environmental engineers are technicians with specific expertise on the sustainability of human presence in the environment. Among other global dilemmas, to the environmental engineers it is often demanded to be able in developing systematic, innovative solutions in order to simultaneously meet water and energy needs, to build resilience to natural and technological disasters, to more accurately gauge and manage countries' greenhouse gas emissions. The general objectives of the Environmental Engineers are to establish actions of environmental sustainability as well as to verify progress toward global goals or international commitments. The globalization of challenges and problems to be faced, leads, in general, to the globalization of the engineering profession. In particular, since the environmental issues are without boundaries, and many and different are the involved professions and the competences, the environmental engineer must have a multidisciplinary and interdisciplinary approach to adequately answer to the demand of technical innovative knowledge at global scale. The environmental engineers, more and more, are involved in international projects were the effective collaboration requires not only the capacity to communicate in a common technical language, but also the assurance of an adequate and common level of technical competences, knowledge and understanding. The Europe-based EUR ACE system, currently operated by ENAEE - European Network for Accreditation of Engineering Education, can represent the proper framework and accreditation system in order to provide a set of measures to assess the quality of engineering degree programmes in Europe and abroad. In the global frame of the knowledge triangle: education-innovation-research, the accreditation and quality assurance of engineering curricula in Europe is discussed with reference to the Environmental engineering curricula, of the 1st and 2nd cycle, based on the European Credit Transfer System and in

  5. Potent Engineered PLGA Nanoparticles by Virtue of Exceptionally High Chemotherapeutic Loadings

    PubMed Central

    Enlow, Elizabeth M.; Luft, J. Christopher; Napier, Mary E.; DeSimone, Joseph M.

    2011-01-01

    Herein we report the fabrication of engineered poly(lactic acid-co-glycolic acid) nanoparticles via the PRINT® (Particle Replication In Non-wetting Templates) process with high and efficient loadings of docetaxel, up to 40% (w/w) with encapsulation efficiencies >90%. The PRINT process enables independent control of particle properties leading to a higher degree of tailorability than traditional methods. Particles with 40% loading display better in vitro efficacy than particles with lower loadings and the clinical formulation of docetaxel, Taxotere®. PMID:21265552

  6. Nanoscale engineering of a cellular interface with semiconductor nanoparticle films for photoelectric stimulation of neurons.

    PubMed

    Pappas, Todd C; Wickramanyake, W M Shan; Jan, Edward; Motamedi, Massoud; Brodwick, Malcolm; Kotov, Nicholas A

    2007-02-01

    The remarkable optical and electrical properties of nanostructured materials are considered now as a source for a variety of biomaterials, biosensing, and cell interface applications. In this study, we report the first example of hybrid bionanodevice where absorption of light by thin films of quantum confined semiconductor nanoparticles of HgTe produced by the layer-by-layer assembly stimulate adherent neural cells via a sequence of photochemical and charge-transfer reactions. We also demonstrate an example of nanoscale engineering of the material driven by biological functionalities.

  7. Manipulation metallic nanoparticle at resonant wavelength using engineered azimuthally polarized optical field.

    PubMed

    Rui, Guanghao; Wang, Xiaoyan; Gu, Bing; Zhan, Qiwen; Cui, Yiping

    2016-04-04

    In this work, we proposed a novel strategy to manipulate the behavior of the metallic nanoparticle under the resonant condition by using engineered azimuthally polarized optical field. Through optimizing the spatial phase distribution of the illumination, the optical force can be tailored to support stable optical trapping while avoiding trap destabilization caused by optical overheating effect simultaneously. Besides, the resonant particle can be stably trapped at predefined location in 3 dimensional space, or revolves around the beam axis with characteristics that can be holistically controlled in terms of both trajectory and rotation direction. The technique demonstrated in this work may open up new avenues for optical manipulation.

  8. Toxicity Assessment of Six Titanium Dioxide Nanoparticles in Human Epidermal Keratinocytes

    EPA Science Inventory

    Toxicity Assessment of Six Titanium Dioxide Nanoparticles in Human Epidermal Keratinocytes Nanoparticle uptake in cells may be an important determinant of their potential cytotoxic and inflammatory effects. Six commercial TiO2 NP (A=Alfa Aesar,10nm, A*=Alfa Aesar 32nm, B=P25 27...

  9. Reverse engineering of metabolic networks, a critical assessment.

    PubMed

    Hendrickx, Diana M; Hendriks, Margriet M W B; Eilers, Paul H C; Smilde, Age K; Hoefsloot, Huub C J

    2011-02-01

    Inferring metabolic networks from metabolite concentration data is a central topic in systems biology. Mathematical techniques to extract information about the network from data have been proposed in the literature. This paper presents a critical assessment of the feasibility of reverse engineering of metabolic networks, illustrated with a selection of methods. Appropriate data are simulated to study the performance of four representative methods. An overview of sampling and measurement methods currently in use for generating time-resolved metabolomics data is given and contrasted with the needs of the discussed reverse engineering methods. The results of this assessment show that if full inference of a real-world metabolic network is the goal there is a large discrepancy between the requirements of reverse engineering of metabolic networks and contemporary measurement practice. Recommendations for improved time-resolved experimental designs are given.

  10. Nanoparticle emissions from a heavy-duty engine running on alternative diesel fuels.

    PubMed

    Heikkilä, Juha; Virtanen, Annele; Rönkkö, Topi; Keskinen, Jorma; Aakko-Saksa, Päivi; Murtonen, Timo

    2009-12-15

    We have studied the effect of three different fuels (fossil diesel fuel (EN590); rapeseed methyl ester (RME); and synthetic gas-to-liquid (GTL)) on heavy-duty diesel engine emissions. Our main focus was on nanoparticle emissions of the engine. Our results show that the particle emissions from a modern diesel engine run with EN590, GTL, or RME consisted of two partly nonvolatile modes that were clearly separated in particle size. The concentration and geometric mean diameter of nonvolatile nucleation mode cores measured with RME were substantially greater than with the other fuels. The soot particle concentration and soot particle size were lowest with RME. With EN590 and GTL, a similar engine load dependence of the nonvolatile nucleation mode particle size and concentration imply a similar formation mechanism of the particles. For RME, the nonvolatile core particle size was larger and the concentration dependence on engine load was clearly different from that of EN590 and GTL. This indicates that the formation mechanism of the core particles is different for RME. This can be explained by differences in the fuel characteristics.

  11. Engine non-containment: UK risk assessment methods

    NASA Technical Reports Server (NTRS)

    Wallin, J. C.

    1977-01-01

    More realistic guideline data must be developed for use in aircraft design in order to comply with recent changes in British civil airworthiness requirements. Unrealistically pessimistic results were obtained when the methodology developed during the Concorde SST certification program was extended to assess catastrophic risks resulting from uncontained engine rotors.

  12. Assessing Students' Motivation to Engage in Sustainable Engineering

    ERIC Educational Resources Information Center

    McCormick, Mary; Bielefeldt, Angela R.; Swan, Christopher W.; Paterson, Kurtis G.

    2015-01-01

    Purpose: The purpose of this study was to design an assessment instrument to evaluate students' attitudes toward sustainable engineering (SE). Factors that impact SE beliefs could then be explored. Design/methodology/approach: Using the definition of sustainability from the Brundtland report and expectancy value theory, students' sentiment toward…

  13. Engineering Student Self-Assessment through Confidence-Based Scoring

    ERIC Educational Resources Information Center

    Yuen-Reed, Gigi; Reed, Kyle B.

    2015-01-01

    A vital aspect of an answer is the confidence that goes along with it. Misstating the level of confidence one has in the answer can have devastating outcomes. However, confidence assessment is rarely emphasized during typical engineering education. The confidence-based scoring method described in this study encourages students to both think about…

  14. Engineering of lipid-coated PLGA nanoparticles with a tunable payload of diagnostically active nanocrystals for medical imaging†

    PubMed Central

    Mieszawska, Aneta J.; Gianella, Anita; Cormode, David P.; Zhao, Yiming; Meijerink, Andries; Langer, Robert; Farokhzad, Omid C.; Fayad, Zahi A.; Mulder, Willem J. M.

    2013-01-01

    Polylactic-co-glycolic acid (PLGA) based nanoparticles are biocompatible and biodegradable and therefore have been extensively investigated as therapeutic carriers. Here, we engineered diagnostically active PLGA nanoparticles that incorporate high payloads of nanocrystals into their core for tunable bioimaging features. We accomplished this through esterification reactions of PLGA to generate polymers modified with nanocrystals. The PLGA nanoparticles formed from modified PLGA polymers that were functionalized with either gold nanocrystals or quantum dots exhibited favorable features for computed tomography and optical imaging, respectively. PMID:22555311

  15. Automotive Stirling engine development program. [fuel economy assessment

    NASA Technical Reports Server (NTRS)

    Kitzner, E. W.

    1978-01-01

    The Ford/DOE automotive Stirling engine development program is directed towards establishing the technological and developmental base that would enable a decision on whether an engineering program should be directed at Stirling engine production. The fuel economy assessment aims to achieve, with a high degree of confidence, the ERDA proposal estimate of 20.6 MPG (gasoline) for a 4500 lb 1WC Stirling engine passenger car. The current M-H fuel economy projection for the 170 HP Stirling engine is 15.7 MPG. The confidence level for this projection is 32%. A confidence level of 29% is projected for a 22.1 MPG estimate. If all of the planned analyses and test work is accomplished at the end of the one year effort, and the projected improvements are substantiated, the confidence levels would rise to 59% for the 20.6 MPG projection and 54% for the 22.1 MPG projection. Progress achieved thus far during the fuel economy assessment is discussed.

  16. Aqueous Aggregation Behavior of Engineered Superparamagnetic Iron Oxide Nanoparticles: Effects of Oxidative Surface Aging.

    PubMed

    Li, Wenlu; Lee, Seung Soo; Mittelman, Anjuliee M; Liu, Di; Wu, Jiewei; Hinton, Carl H; Abriola, Linda M; Pennell, Kurt D; Fortner, John D

    2016-12-06

    For successful aqueous-based applications, it is necessary to fundamentally understand and control nanoparticle dispersivity and stability over a range of dynamic conditions, including variable ionic strengths/types, redox chemistries, and surface ligand reactivity/degradation states (i.e., surface aging). Here, we quantitatively describe the behavior of artificially aged, oleic acid (OA) bilayer coated iron oxide nanoparticles (IONPs) under different scenarios. Hydrogen peroxide (H2O2), used here as a model oxidant under both dark and light ultraviolet (UVA) conditions, was employed to "age" materials, to varying degrees, without increasing ionic strength. Short-term stability experiments indicate that OA-IONPs, while stable in the dark, are effectively destabilized when exposed to UVA/H2O2/•OH based oxidation processes. Compared to bicarbonate, phosphate (1.0 mM) has a net stabilizing effect on OA-IONPs under oxidative conditions, which can be attributed to (surface-based) functional adsorption. Corresponding aggregation kinetics in the presence of monovalent (Na(+)) and divalent cations (Ca(2+)) show that attachment efficiencies (α) are strongly dependent on the cation concentrations/types and degree of surface aging. Taken together, our findings directly highlight the need to understand the critical role of particle surface transformation(s), via oxidative aging, among other routes, with regard to the ultimate stability and environmental fate of surface functionalized engineered nanoparticles.

  17. Interior engineering of a viral nanoparticle and its tumor homing properties.

    PubMed

    Wen, Amy M; Shukla, Sourabh; Saxena, Pooja; Aljabali, Alaa A A; Yildiz, Ibrahim; Dey, Sourav; Mealy, Joshua E; Yang, Alice C; Evans, David J; Lomonossoff, George P; Steinmetz, Nicole F

    2012-12-10

    The development of multifunctional nanoparticles for medical applications is of growing technological interest. A single formulation containing imaging and/or drug moieties that is also capable of preferential uptake in specific cells would greatly enhance diagnostics and treatments. There is growing interest in plant-derived viral nanoparticles (VNPs) and establishing new platform technologies based on these nanoparticles inspired by nature. Cowpea mosaic virus (CPMV) serves as the standard model for VNPs. Although exterior surface modification is well-known and has been comprehensively studied, little is known of interior modification. Additional functionality conferred by the capability for interior engineering would be of great benefit toward the ultimate goal of targeted drug delivery. Here, we examined the capacity of empty CPMV (eCPMV) particles devoid of RNA to encapsulate a wide variety of molecules. We systematically investigated the conjugation of fluorophores, biotin affinity tags, large molecular weight polymers such as poly(ethylene glycol) (PEG), and various peptides through targeting reactive cysteines displayed selectively on the interior surface. Several methods are described that mutually confirm specific functionalization of the interior. Finally, CPMV and eCPMV were labeled with near-infrared fluorophores and studied side-by-side in vitro and in vivo. Passive tumor targeting via the enhanced permeability and retention effect and optical imaging were confirmed using a preclinical mouse model of colon cancer. The results of our studies lay the foundation for the development of the eCPMV platform in a range of biomedical applications.

  18. Interior engineering of a viral nanoparticle and its tumor homing properties

    PubMed Central

    Wen, Amy M.; Shukla, Sourabh; Saxena, Pooja; Aljabali, Alaa A.A.; Yildiz, Ibrahim; Dey, Sourav; Mealy, Joshua E.; Yang, Alice C.; Evans, David J.; Lomonossoff, George P.; Steinmetz, Nicole F.

    2012-01-01

    The development of multifunctional nanoparticles for medical applications is of growing technological interest. A single formulation containing imaging and/or drug moieties that is also capable of preferential uptake in specific cells would greatly enhance diagnostics and treatments. There is growing interest in plant-derived viral nanoparticles (VNPs) and establishing new platform technologies based on these nanoparticles inspired by nature. Cowpea mosaic virus (CPMV) serves as the standard model for VNPs. Although exterior surface modification is well known and has been comprehensively studied, little is known of interior modification. Additional functionality conferred by the capability for interior engineering would be of great benefit toward the ultimate goal of targeted drug delivery. Here, we examined the capacity of empty CPMV (eCPMV) particles devoid of RNA to encapsulate a wide variety of molecules. We systematically investigated the conjugation of fluorophores, biotin affinity tags, large molecular weight polymers such as polyethylene glycol (PEG), and various peptides through targeting reactive cysteines displayed selectively on the interior surface. Several methods are described that mutually confirm specific functionalization of the interior. Finally, CPMV and eCPMV were labeled with near-infrared fluorophores and studied side-by-side in vitro and in vivo. Passive tumor targeting via the enhanced permeability and retention effect and optical imaging were confirmed using a preclinical mouse model of colon cancer. The results of our studies lay the foundation for the development of the eCPMV platform in a range of biomedical applications. PMID:23121655

  19. Influence of real-world engine load conditions on nanoparticle emissions from a DPF and SCR equipped heavy-duty diesel engine.

    PubMed

    Thiruvengadam, Arvind; Besch, Marc C; Carder, Daniel K; Oshinuga, Adewale; Gautam, Mridul

    2012-02-07

    The experiments aimed at investigating the effect of real-world engine load conditions on nanoparticle emissions from a Diesel Particulate Filter and Selective Catalytic Reduction after-treatment system (DPF-SCR) equipped heavy-duty diesel engine. The results showed the emission of nucleation mode particles in the size range of 6-15 nm at conditions with high exhaust temperatures. A direct result of higher exhaust temperatures (over 380 °C) contributing to higher concentration of nucleation mode nanoparticles is presented in this study. The action of an SCR catalyst with urea injection was found to increase the particle number count by over an order of magnitude in comparison to DPF out particle concentrations. Engine operations resulting in exhaust temperatures below 380 °C did not contribute to significant nucleation mode nanoparticle concentrations. The study further suggests the fact that SCR-equipped engines operating within the Not-To-Exceed (NTE) zone over a critical exhaust temperature and under favorable ambient dilution conditions could contribute to high nanoparticle concentrations to the environment. Also, some of the high temperature modes resulted in DPF out accumulation mode (between 50 and 200 nm) particle concentrations an order of magnitude greater than typical background PM concentrations. This leads to the conclusion that sustained NTE operation could trigger high temperature passive regeneration which in turn would result in lower filtration efficiencies of the DPF that further contributes to the increased solid fraction of the PM number count.

  20. Nanoparticles in the environment: assessment using the causal diagram approach

    PubMed Central

    2012-01-01

    Nanoparticles (NPs) cause concern for health and safety as their impact on the environment and humans is not known. Relatively few studies have investigated the toxicological and environmental effects of exposure to naturally occurring NPs (NNPs) and man-made or engineered NPs (ENPs) that are known to have a wide variety of effects once taken up into an organism. A review of recent knowledge (between 2000-2010) on NP sources, and their behaviour, exposure and effects on the environment and humans was performed. An integrated approach was used to comprise available scientific information within an interdisciplinary logical framework, to identify knowledge gaps and to describe environment and health linkages for NNPs and ENPs. The causal diagram has been developed as a method to handle the complexity of issues on NP safety, from their exposure to the effects on the environment and health. It gives an overview of available scientific information starting with common sources of NPs and their interactions with various environmental processes that may pose threats to both human health and the environment. Effects of NNPs on dust cloud formation and decrease in sunlight intensity were found to be important environmental changes with direct and indirect implication in various human health problems. NNPs and ENPs exposure and their accumulation in biological matrices such as microbiota, plants and humans may result in various adverse effects. The impact of some NPs on human health by ROS generation was found to be one of the major causes to develop various diseases. A proposed cause-effects diagram for NPs is designed considering both NNPs and ENPs. It represents a valuable information package and user-friendly tool for various stakeholders including students, researchers and policy makers, to better understand and communicate on issues related to NPs. PMID:22759495

  1. Nanoparticle toxicity assessment using an in vitro 3-D kidney organoid culture model.

    PubMed

    Astashkina, Anna I; Jones, Clint F; Thiagarajan, Giridhar; Kurtzeborn, Kristen; Ghandehari, Hamid; Brooks, Benjamin D; Grainger, David W

    2014-08-01

    Nanocarriers and nanoparticles remain an intense pharmaceutical and medical imaging technology interest. Their entry into clinical use is hampered by the lack of reliable in vitro models that accurately predict in vivo toxicity. This study evaluates a 3-D kidney organoid proximal tubule culture to assess in vitro toxicity of the hydroxylated generation-5 PAMAM dendrimer (G5-OH) compared to previously published preclinical in vivo rodent nephrotoxicity data. 3-D kidney proximal tubule cultures were created using isolated murine proximal tubule fractions suspended in a biomedical grade hyaluronic acid-based hydrogel. Toxicity in these cultures to neutral G5-OH dendrimer nanoparticles and gold nanoparticles in vitro was assessed using clinical biomarker generation. Neutral PAMAM nanoparticle dendrimers elicit in vivo-relevant kidney biomarkers and cell viability in a 3-D kidney organoid culture that closely reflect toxicity markers reported in vivo in rodent nephrotoxicity models exposed to this same nanoparticle.

  2. Space Shuttle Main Engine turbopump bearing assessment program

    NASA Technical Reports Server (NTRS)

    Breithaupt, Barbara Spiegel

    1994-01-01

    This paper documents the work done on the bearing assessment program over the past two and a half years. The objective of the program is to develop a nondestructive evaluation system for the space shuttle main engine high pressure oxidizer turbopumps which would be used to detect anomalies in installed bearings without component disassembly. Databases of various signatures are obtained by slowly turning the pump shafts before and after an engine firing. These signatures are then analyzed and compared to the original signatures to more accurately predict bearing wear.

  3. Space Shuttle main engine turbopump bearing assessment program

    NASA Technical Reports Server (NTRS)

    Breithaupt, B. Spiegel

    1994-01-01

    This report documents the work done on the bearing assessment program over the past two and a half years. The objective of the program is to develop a nondestructive evaluation system for the SSME HPOTP's which would be used to detect anomalies in installed bearings without engine disassembly. Data bases of various signatures are obtained by slowly turning the pump shafts before and after an engine firing. These signatures are then analyzed and compared to the original signatures to more accurately predict bearing wear.

  4. Detection of Engineered Copper Nanoparticles in Soil Using Single Particle ICP-MS

    PubMed Central

    Navratilova, Jana; Praetorius, Antonia; Gondikas, Andreas; Fabienke, Willi; von der Kammer, Frank; Hofmann, Thilo

    2015-01-01

    Regulatory efforts rely on nanometrology for the development and implementation of laws regarding the incorporation of engineered nanomaterials (ENMs) into industrial and consumer products. Copper is currently one of the most common metals used in the constantly developing and expanding sector of nanotechnology. The use of copper nanoparticles in products, such as agricultural biocides, cosmetics and paints, is increasing. Copper based ENMs will eventually be released to the environment through the use and disposal of nano-enabled products, however, the detection of copper ENMs in environmental samples is a challenging task. Single particle inductively coupled plasma mass spectroscopy (spICP-MS) has been suggested as a powerful tool for routine nanometrology efforts. In this work, we apply a spICP-MS method for the detection of engineered copper nanomaterials in colloidal extracts from natural soil samples. Overall, copper nanoparticles were successfully detected in the soil colloidal extracts and the importance of dwell time, background removal, and sample dilution for method optimization and recovery maximization is highlighted. PMID:26690460

  5. Detection of Engineered Copper Nanoparticles in Soil Using Single Particle ICP-MS.

    PubMed

    Navratilova, Jana; Praetorius, Antonia; Gondikas, Andreas; Fabienke, Willi; von der Kammer, Frank; Hofmann, Thilo

    2015-12-10

    Regulatory efforts rely on nanometrology for the development and implementation of laws regarding the incorporation of engineered nanomaterials (ENMs) into industrial and consumer products. Copper is currently one of the most common metals used in the constantly developing and expanding sector of nanotechnology. The use of copper nanoparticles in products, such as agricultural biocides, cosmetics and paints, is increasing. Copper based ENMs will eventually be released to the environment through the use and disposal of nano-enabled products, however, the detection of copper ENMs in environmental samples is a challenging task. Single particle inductively coupled plasma mass spectroscopy (spICP-MS) has been suggested as a powerful tool for routine nanometrology efforts. In this work, we apply a spICP-MS method for the detection of engineered copper nanomaterials in colloidal extracts from natural soil samples. Overall, copper nanoparticles were successfully detected in the soil colloidal extracts and the importance of dwell time, background removal, and sample dilution for method optimization and recovery maximization is highlighted.

  6. NIOSH Field Studies Team Assessment: Worker Exposure to Aerosolized Metal Oxide Nanoparticles in a Semiconductor Fabrication Facility

    PubMed Central

    Brenner, Sara A.; Neu-Baker, Nicole M.; Eastlake, Adrienne C.; Beaucham, Catherine C.; Geraci, Charles L.

    2016-01-01

    The ubiquitous use of engineered nanomaterials – particulate materials measuring approximately 1–100 nanometers (nm) on their smallest axis, intentionally engineered to express novel properties – in semiconductor fabrication poses unique issues for protecting worker health and safety. Use of new substances or substances in a new form may present hazards that have yet to be characterized for their acute or chronic health effects. Uncharacterized or emerging occupational health hazards may exist when there is insufficient validated hazard data available to make a decision on potential hazard and risk to exposed workers under condition of use. To advance the knowledge of potential worker exposure to engineered nanomaterials, the National Institute for Occupational Safety and Health Nanotechnology Field Studies Team conducted an on-site field evaluation in collaboration with on-site researchers at a semiconductor research and development facility on April 18–21, 2011. The Nanomaterial Exposure Assessment Technique (2.0) was used to perform a complete exposure assessment. A combination of filter-based sampling and direct-reading instruments was used to identify, characterize, and quantify the potential for worker inhalation exposure to airborne alumina and amorphous silica nanoparticles associated with the chemical mechanical planarization wafer polishing process. Engineering controls and work practices were evaluated to characterize tasks that might contribute to potential exposures and to assess existing engineering controls. Metal oxide structures were identified in all sampling areas, as individual nanoparticles and agglomerates ranging in size from 60nm to >1,000nm, with varying structure morphology, from long and narrow to compact. Filter-based samples indicated very little aerosolized material in task areas or worker breathing zone. Direct-reading instrument data indicated increased particle counts relative to background in the wastewater treatment area

  7. Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis.

    PubMed

    Johnson, Monique E; Hanna, Shannon K; Montoro Bustos, Antonio R; Sims, Christopher M; Elliott, Lindsay C C; Lingayat, Akshay; Johnston, Adrian C; Nikoobakht, Babak; Elliott, John T; Holbrook, R David; Scott, Keana C K; Murphy, Karen E; Petersen, Elijah J; Yu, Lee L; Nelson, Bryant C

    2017-01-24

    For environmental studies assessing uptake of orally ingested engineered nanoparticles (ENPs), a key step in ensuring accurate quantification of ingested ENPs is efficient separation of the organism from ENPs that are either nonspecifically adsorbed to the organism and/or suspended in the dispersion following exposure. Here, we measure the uptake of 30 and 60 nm gold nanoparticles (AuNPs) by the nematode, Caenorhabditis elegans, using a sucrose density gradient centrifugation protocol to remove noningested AuNPs. Both conventional inductively coupled plasma mass spectrometry (ICP-MS) and single particle (sp)ICP-MS are utilized to measure the total mass and size distribution, respectively, of ingested AuNPs. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) imaging confirmed that traditional nematode washing procedures were ineffective at removing excess suspended and/or adsorbed AuNPs after exposure. Water rinsing procedures had AuNP removal efficiencies ranging from 57 to 97% and 22 to 83%, while the sucrose density gradient procedure had removal efficiencies of 100 and 93 to 98%, respectively, for the 30 and 60 nm AuNP exposure conditions. Quantification of total Au uptake was performed following acidic digestion of nonexposed and Au-exposed nematodes, whereas an alkaline digestion procedure was optimized for the liberation of ingested AuNPs for spICP-MS characterization. Size distributions and particle number concentrations were determined for AuNPs ingested by nematodes with corresponding confirmation of nematode uptake via high-pressure freezing/freeze substitution resin preparation and large-area SEM imaging. Methods for the separation and in vivo quantification of ENPs in multicellular organisms will facilitate robust studies of ENP uptake, biotransformation, and hazard assessment in the environment.

  8. Engineering Nanostructures by Decorating Magnetic Nanoparticles onto Graphene Oxide Sheets to Shield Electromagnetic Radiations.

    PubMed

    Mural, Prasanna Kumar S; Pawar, Shital Patangrao; Jayanthi, Swetha; Madras, Giridhar; Sood, Ajay K; Bose, Suryasarathi

    2015-08-05

    In this study, a minimum reflection loss of -70 dB was achieved for a 6 mm thick shield (at 17.1 GHz frequency) employing a unique approach. This was accomplished by engineering nanostructures through decoration of magnetic nanoparticles (nickel, Ni) onto graphene oxide (GO) sheets. Enhanced electromagnetic (EM) shielding was derived by selectively localizing the nanoscopic particles in a specific phase of polyethylene (PE)/poly(ethylene oxide) (PEO) blends. By introduction of a conducting inclusion (like multiwall carbon nanotubes, MWNTs) together with the engineered nanostructures (nickel-decorated GO, GO-Ni), the shielding efficiency can be enhanced significantly in contrast to physically mixing the particles in the blends. For instance, the composites showed a shielding efficiency >25 dB for a combination of MWNTs (3 wt %) and Ni nanoparticles (52 wt %) in PE/PEO blends. However, similar shielding effectiveness could be achieved for a combination of MWNTs (3 wt %) and 10 vol % of GO-Ni where in the effective concentration of Ni was only 19 wt %. The GO-Ni sheets facilitated in an efficient charge transfer as manifested from high electrical conductivity in the blends besides enhancing the permeability in the blends. It is envisioned that GO is simultaneously reduced in the process of synthesizing GO-Ni, and this facilitated in efficient charge transfer between the neighboring CNTs. More interestingly, the blends with MWNTs/GO-Ni attenuated the incoming EM radiation mostly by absorption. This study opens new avenues in designing polyolefin-based lightweight shielding materials by engineering nanostructures for numerous applications.

  9. Nondestructive Assessment of Engineered Cartilage Composition by Near Infrared Spectroscopy.

    PubMed

    McGoverin, Cushla M; Hanifi, Arash; Palukuru, Uday P; Yousefi, Farzad; Glenn, Padraig B M; Shockley, Michael; Spencer, Richard G; Pleshko, Nancy

    2016-03-01

    Tissue engineering presents a strategy to overcome the limitations of current tissue healing methods. Scaffolds, cells, external growth factors and mechanical input are combined in an effort to obtain constructs with properties that mimic native tissues. However, engineered constructs developed using similar culture environments can have very different matrix composition and biomechanical properties. Accordingly, a nondestructive technique to assess constructs during development such that appropriate compositional endpoints can be defined is desirable. Near infrared spectroscopy (NIRS) analysis is a modality being investigated to address the challenges associated with current evaluation techniques, which includes nondestructive compositional assessment. In the present study, cartilage tissue constructs were grown using chondrocytes seeded onto polyglycolic acid (PGA) scaffolds in similar environments in three separate tissue culture experiments and monitored using NIRS. Multivariate partial least squares (PLS) analysis models of NIR spectra were calculated and used to predict tissue composition, with biochemical assay information used as the reference data. Results showed that for combined data from all tissue culture experiments, PLS models were able to assess composition with significant correlations to reference values, including engineered cartilage water (at 5200 cm(-1), R = 0.68, p = 0.03), proteoglycan (at 4310 cm(-1), R = 0.82, p = 0.007), and collagen (at 4610 cm(-1), R = 0.84, p = 0.005). In addition, degradation of PGA was monitored using specific NIRS frequencies. These results demonstrate that NIR spectroscopy combined with multivariate analysis provides a nondestructive modality to assess engineered cartilage, which could provide information to determine the optimal time for tissue harvest for clinical applications.

  10. Soil-pore water distribution of silver and gold engineered nanoparticles in undisturbed soils under unsaturated conditions.

    PubMed

    Tavares, D S; Rodrigues, S M; Cruz, N; Carvalho, C; Teixeira, T; Carvalho, L; Duarte, A C; Trindade, T; Pereira, E; Römkens, P F A M

    2015-10-01

    Release of engineered nanoparticles (ENPs) to soil is well documented but little is known on the subsequent soil-pore water distribution of ENPs once present in soil. In this study, the availability and mobility of silver (Ag) and gold (Au) ENPs added to agricultural soils were assessed in two separate pot experiments. Pore water samples collected from pots from day 1 to 45 using porous (<0.17 μm) membrane samplers suggest that both Ag and Au are retained almost completely within 24 h with less than 13% of the total added amount present in pore water on day 1. UV-Vis and TEM results showed that AuENPs in pore water were present as both homoaggregates and heteroaggregates until day 3 after which the concentration in pore water was too low to detect the presence of aggregates. A close relation between the concentration of Au and Fe in pore water suggests that the short term solubility of Au is partly controlled by natural soil colloids. Results suggest that under normal aerated soil conditions the actual availability of Ag and AuENPs is low which is relevant in view of risk assessment even though the impact of environmental conditions and soil properties on the reactivity of ENPs (and/or large ENPs aggregates) retained in the solid matrix need to be addressed further.

  11. Incorporation of continuous student assessment into lectures in engineering education

    NASA Astrophysics Data System (ADS)

    Myllymäki, S.

    2013-08-01

    A continuous student assessment system was incorporated into an advanced microelectronic course. This study investigated the relationship between the continuous assessment system based on home exams and individual student achievement. The perspective was based on the learning frameworks of the social constructivist theory. Six fourth-year engineering students participated in the study, which covered 13 lectures and 5 home exams. Feedback sessions concerning the particular exam were held after every exam. Correlations between the exams, the feedback, and individual student achievement were computed. The results indicated a positive correlation between continuous assessment and student achievement. Rather than being improved a lot, student achievement stabilised statistically at a higher level. Additionally, student's absence was very low (5%) despite the voluntary participation in the course. Continuous assessment realised with home exams induced two-way discussions between the teacher and the students. Unprompted, the students learned additional material and discussed it in the exam essays, confirming the principles of social constructivist theory.

  12. Synthesis of Hollow Gold-Silver Alloyed Nanoparticles: A "Galvanic Replacement" Experiment for Chemistry and Engineering Students

    ERIC Educational Resources Information Center

    Jenkins, Samir V.; Gohman, Taylor D.; Miller, Emily K.; Chen, Jingyi

    2015-01-01

    The rapid academic and industrial development of nanotechnology has led to its implementation in laboratory teaching for undergraduate-level chemistry and engineering students. This laboratory experiment introduces the galvanic replacement reaction for synthesis of hollow metal nanoparticles and investigates the optical properties of these…

  13. Sensing the Presence and Transport of Engineered Nanoparticles in Saturated PorousMedia using Spectral Induced Polarization (SIP) Method

    EPA Science Inventory

    Nano-materials are emerging into the global marketplace. Engineered Nano-particles, and other throwaway nanodevices may constitute a whole new class of non-biodegradable pollutants of which scientists have very little understanding. Therefore, the production of significant quanti...

  14. Small Angle X-ray Scattering Study of Palladium Nanoparticle Growth on Genetically Engineered Tobacco Mosaic Virus Nanotemplates

    NASA Astrophysics Data System (ADS)

    Manocchi, Amy K.

    Transition metal nanoparticles possess valuable specific size dependent properties that arise at the nanoscale, and differ significantly from their bulk properties. However, the fabrication of these nanoparticles is often difficult to predict and control due to harsh reaction conditions and effects of capping agents or surfactants. Therefore, there is a critical need for facile routes toward controllable nanoparticle fabrication. Biological supramolecules, such as viruses, offer attractive templates for nanoparticle synthesis, due to their precise size and shape. In addition, simple genetic modifications can be employed to confer additional functionality with a high number of precisely spaced functional groups. In this work we exploit the specificity of genetically modified Tobacco Mosaic Virus (TMV1cys) for readily controllable palladium (Pd) nanoparticle synthesis via simple electroless deposition. TMV1cys, engineered to display one cysteine residue on the surface of each of over 2000 identical coat proteins, provides high density precisely spaced thiol groups for the preferential nucleation and growth of Pd nanoparticles. Small-Angle X-ray Scattering (SAXS) was employed to provide a statistically meaningful route to the investigation of Pd nanoparticle size ranges formed on the viral-nanotemplates. Specifically, we examine the size range and thermal stability of Pd nanoparticles formed on surface assembled TMV1cys. Further, we investigate the growth of Pd nanoparticles on TMV1cys in solution using in situ SAXS to better understand and predict nanoparticle growth on these nanotemplates. Lastly, we compare TMV1cys templated particle growth to Pd nanoparticle growth in the absence of TMV1cys to elucidate the role of TMV in particle formation. We show that Pd nanoparticles form preferentially on surface assembled TMV1cys in high density in a broad particle size range (4-18nm). Further, we show that Pd nanoparticles are significantly smaller and more uniform when

  15. Environmental exposure assessment framework for nanoparticles in solid waste

    NASA Astrophysics Data System (ADS)

    Boldrin, Alessio; Hansen, Steffen Foss; Baun, Anders; Hartmann, Nanna Isabella Bloch; Astrup, Thomas Fruergaard

    2014-06-01

    Information related to the potential environmental exposure of engineered nanomaterials (ENMs) in the solid waste management phase is extremely scarce. In this paper, we define nanowaste as separately collected or collectable waste materials which are or contain ENMs, and we present a five-step framework for the systematic assessment of ENM exposure during nanowaste management. The framework includes deriving EOL nanoproducts and evaluating the physicochemical properties of the nanostructure, matrix properties and nanowaste treatment processes as well as transformation processes and environment releases, eventually leading to a final assessment of potential ENM exposure. The proposed framework was applied to three selected nanoproducts: nanosilver polyester textile, nanoTiO2 sunscreen lotion and carbon nanotube tennis racquets. We found that the potential global environmental exposure of ENMs associated with these three products was an estimated 0.5-143 Mg/year, which can also be characterised qualitatively as medium, medium, low, respectively. Specific challenges remain and should be subject to further research: (1) analytical techniques for the characterisation of nanowaste and its transformation during waste treatment processes, (2) mechanisms for the release of ENMs, (3) the quantification of nanowaste amounts at the regional scale, (4) a definition of acceptable limit values for exposure to ENMs from nanowaste and (5) the reporting of nanowaste generation data.

  16. Comparative DNA damage and transcriptomic effects of engineered nanoparticles in human lung cells in vitro

    EPA Science Inventory

    A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), various types of DNA damage, and transcriptional changes in human respiratory BEAS-2B cells exposed in vitro at se...

  17. Assessment of carbon nanoparticle exposure on murine macrophage function

    NASA Astrophysics Data System (ADS)

    Suro-Maldonado, Raquel M.

    There is growing concern about the potential cytotoxicity of nanoparticles. Exposure to respirable ultrafine particles (2.5uM) can adversely affect human health and have been implicated with episodes of increased respiratory diseases such as asthma and allergies. Nanoparticles are of particular interest because of their ability to penetrate into the lung and potentially elicit health effects triggering immune responses. Nanoparticles are structures and devises with length scales in the 1 to 100-nanometer range. Black carbon (BC) nanoparticles have been observed to be products of combustion, especially flame combustion and multi-walled carbon nanotubes (MWCNT) have been shown to be found in both indoor and outdoor air. Furthermore, asbestos, which have been known to cause mesothelioma as well as lung cancer, have been shown to be structurally identical to MWCNTs. The aims of these studies were to examine the effects of carbon nanoparticles on murine macrophage function and clearance mechanisms. Macrophages are immune cells that function as the first line of defense against invading pathogens and are likely to be amongst the first cells affected by nanoparticles. Our research focused on two manufactured nanoparticles, MWCNT and BC. The two were tested against murine-derived macrophages in a chronic contact model. We hypothesized that long-term chronic exposure to carbon nanoparticles would decrease macrophages ability to effectively respond to immunological challenge. Production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), cell surface macrophage; activation markers, reactive oxygen species formation (ROS), and antigen processing and presentation were examined in response to lipopolysaccharide (LPS) following a 144hr exposure to the particulates. Data demonstrated an increase in TNF-alpha, and NO production; a decrease in phagocytosis and antigen processing and presentation; and a decrease in the expression levels of cell surface macrophage

  18. Effect of engineered nanoparticles on vasomotor responses in rat intrapulmonary artery

    SciTech Connect

    Courtois, Arnaud; Andujar, Pascal; Ladeiro, Yannick; Ducret, Thomas; Rogerieux, Francoise; Lacroix, Ghislaine; Baudrimont, Isabelle; Guibert, Christelle; Roux, Etienne; Canal-Raffin, Mireille; Brochard, Patrick; Marano, Francelyne; Marthan, Roger; Muller, Bernard

    2010-06-01

    Pulmonary circulation could be one of the primary vascular targets of finest particles that can deeply penetrate into the lungs after inhalation. We investigated the effects of engineered nanoparticles on vasomotor responses of small intrapulmonary arteries using isometric tension measurements. Acute in vitro exposure to carbon nanoparticles (CNP) decreased, and in some case abolished, the vasomotor responses induced by several vasoactive agents, whereas acute exposure to titanium dioxide nanoparticles (TiO{sub 2}NP) did not. This could be attributed to a decrease in the activity of those vasoactive agents (including PGF{sub 2{alpha}}, serotonin, endothelin-1 and acetylcholine), as suggested when they were exposed to CNP before being applied to arteries. Also, CNP decreased the contraction induced by 30 mM KCl, without decreasing its activity. After endoplasmic reticulum calcium stores depletion (by caffeine and thapsigargin), CaCl{sub 2} addition induced a contraction, dependent on Store-Operated Calcium Channels that was not modified by acute CNP exposure. Further addition of 30 mM KCl elicited a contraction, originating from activation of Voltage-Operated Calcium Channels that was diminished by CNP. Contractile responses to PGF{sub 2{alpha}} or KCl, and relaxation to acetylcholine were modified neither in pulmonary arteries exposed in vitro for prolonged time to CNP or TiO{sub 2}NP, nor in those removed from rats intratracheally instilled with CNP or TiO{sub 2}NP. In conclusion, prolonged in vitro or in vivo exposure to CNP or TiO{sub 2}NP does not affect vasomotor responses of pulmonary arteries. However, acute exposure to CNP decreases contraction mediated by activation of Voltage-Operated, but not Store-Operated, Calcium Channels. Moreover, interaction of some vasoactive agents with CNP decreases their biological activity that might lead to misinterpretation of experimental data.

  19. Gene Expression Profiling of Immune-Competent Human Cells Exposed to Engineered Zinc Oxide or Titanium Dioxide Nanoparticles

    PubMed Central

    Tuomela, Soile; Autio, Reija; Buerki-Thurnherr, Tina; Arslan, Osman; Kunzmann, Andrea; Andersson-Willman, Britta; Wick, Peter; Mathur, Sanjay; Scheynius, Annika; Krug, Harald F.; Fadeel, Bengt; Lahesmaa, Riitta

    2013-01-01

    A comprehensive in vitro assessment of two commercial metal oxide nanoparticles, TiO2 and ZnO, was performed using human monocyte-derived macrophages (HMDM), monocyte-derived dendritic cells (MDDC), and Jurkat T cell leukemia-derived cell line. TiO2 nanoparticles were found to be non-toxic whereas ZnO nanoparticles caused dose-dependent cell death. Subsequently, global gene expression profiling was performed to identify transcriptional response underlying the cytotoxicity caused by ZnO nanoparticles. Analysis was done with doses 1 µg/ml and 10 µg/ml after 6 and 24 h of exposure. Interestingly, 2703 genes were significantly differentially expressed in HMDM upon exposure to 10 µg/ml ZnO nanoparticles, while in MDDCs only 12 genes were affected. In Jurkat cells, 980 genes were differentially expressed. It is noteworthy that only the gene expression of metallothioneins was upregulated in all the three cell types and a notable proportion of the genes were regulated in a cell type-specific manner. Gene ontology analysis revealed that the top biological processes disturbed in HMDM and Jurkat cells were regulating cell death and growth. In addition, genes controlling immune system development were affected. Using a panel of modified ZnO nanoparticles, we obtained an additional support that the cellular response to ZnO nanoparticles is largely dependent on particle dissolution and show that the ligand used to modify ZnO nanoparticles modulates Zn2+ leaching. Overall, the study provides an extensive resource of transcriptional markers for mediating ZnO nanoparticle-induced toxicity for further mechanistic studies, and demonstrates the value of assessing nanoparticle responses through a combined transcriptomics and bioinformatics approach. PMID:23894303

  20. Communication Needs Assessment for Distributed Turbine Engine Control

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Behbahani, Alireza R.

    2008-01-01

    Control system architecture is a major contributor to future propulsion engine performance enhancement and life cycle cost reduction. The control system architecture can be a means to effect net weight reduction in future engine systems, provide a streamlined approach to system design and implementation, and enable new opportunities for performance optimization and increased awareness about system health. The transition from a centralized, point-to-point analog control topology to a modular, networked, distributed system is paramount to extracting these system improvements. However, distributed engine control systems are only possible through the successful design and implementation of a suitable communication system. In a networked system, understanding the data flow between control elements is a fundamental requirement for specifying the communication architecture which, itself, is dependent on the functional capability of electronics in the engine environment. This paper presents an assessment of the communication needs for distributed control using strawman designs and relates how system design decisions relate to overall goals as we progress from the baseline centralized architecture, through partially distributed and fully distributed control systems.

  1. Engineered Human Ferritin Nanoparticles for Direct Delivery of Tumor Antigens to Lymph Node and Cancer Immunotherapy

    PubMed Central

    Lee, Bo-Ram; Ko, Ho Kyung; Ryu, Ju Hee; Ahn, Keum Young; Lee, Young-Ho; Oh, Se Jin; Na, Jin Hee; Kim, Tae Woo; Byun, Youngro; Kwon, Ick Chan; Kim, Kwangmeyung; Lee, Jeewon

    2016-01-01

    Efficient delivery of tumor-specific antigens (TSAs) to lymph nodes (LNs) is essential to eliciting robust immune response for cancer immunotherapy but still remains unsolved. Herein, we evaluated the direct LN-targeting performance of four different protein nanoparticles with different size, shape, and origin [Escherichia coli DNA binding protein (DPS), Thermoplasma acidophilum proteasome (PTS), hepatitis B virus capsid (HBVC), and human ferritin heavy chain (hFTN)] in live mice, using an optical fluorescence imaging system. Based on the imaging results, hFTN that shows rapid LN targeting and prolonged retention in LNs was chosen as a carrier of the model TSA [red fluorescence protein (RFP)], and the flexible surface architecture of hFTN was engineered to densely present RFPs on the hFTN surface through genetic modification of subunit protein of hFTN. The RFP-modified hFTN rapidly targeted LNs, sufficiently exposed RFPs to LN immune cells during prolonged period of retention in LNs, induced strong RFP-specific cytotoxic CD8+ T cell response, and notably inhibited RFP-expressing melanoma tumor growth in live mice. This suggests that the strategy using protein nanoparticles as both TSA-carrying scaffold and anti-cancer vaccine holds promise for clinically effective immunotherapy of cancer. PMID:27725782

  2. Manufacturing Techniques and Surface Engineering of Polymer Based Nanoparticles for Targeted Drug Delivery to Cancer

    PubMed Central

    Wang, Yichao; Li, Puwang; Truong-Dinh Tran, Thao; Zhang, Juan; Kong, Lingxue

    2016-01-01

    The evolution of polymer based nanoparticles as a drug delivery carrier via pharmaceutical nano/microencapsulation has greatly promoted the development of nano- and micro-medicine in the past few decades. Poly(lactide-co-glycolide) (PLGA) and chitosan, which are biodegradable and biocompatible polymers, have been approved by both the Food & Drug Administration (FDA) and European Medicine Agency (EMA), making them ideal biomaterials that can be advanced from laboratory development to clinical oral and parental administrations. PLGA and chitosan encapsulated nanoparticles (NPs) have successfully been developed as new oral drug delivery systems with demonstrated high efficacy. This review aims to provide a comprehensive overview of the fabrication of PLGA and chitosan particulate systems using nano/microencapsulation methods, the current progress and the future outlooks of the nanoparticulate drug delivery systems. Especially, we focus on the formulations and nano/micro-encapsulation techniques using top-down techniques. It also addresses how the different phases including the organic and aqueous ones in the emulsion system interact with each other and subsequently influence the properties of the drug delivery system. Besides, surface modification strategies which can effectively engineer intrinsic physicochemical properties are summarised. Finally, future perspectives and potential directions of PLGA and chitosan nano/microencapsulated drug systems are outlined. PMID:28344283

  3. Effects of Engineered Nanoparticles on the Assembly of Exopolymeric Substances from Phytoplankton

    PubMed Central

    Zhang, Saijin; Spurgin, Jessica; Chuang, Chia-Ying; Xu, Chen; Miao, Ai-Jun; Chen, Eric Y-T.; Schwehr, Kathleen A.; Jiang, Yuelu; Quigg, Antonietta; Santschi, Peter H.; Chin, Wei-Chun

    2011-01-01

    The unique properties of engineered nanoparticles (ENs) that make their industrial applications so attractive simultaneously raise questions regarding their environmental safety. ENs exhibit behaviors different from bulk materials with identical chemical compositions. Though the nanotoxicity of ENs has been studied intensively, their unintended environmental impacts remain largely unknown. Herein we report experimental results of EN interactions with exopolymeric substances (EPS) from three marine phytoplankton species: Amphora sp., Ankistrodesmus angustus and Phaeodactylum tricornutum. EPS are polysaccharide-rich anionic colloid polymers released by various microorganisms that can assemble into microgels, possibly by means of hydrophobic and ionic mechanisms. Polystyrene nanoparticles (23 nm) were used in our study as model ENs. The effects of ENs on EPS assembly were monitored with dynamic laser scattering (DLS). We found that ENs can induce significant acceleration in Amphora sp. EPS assembly; after 72 hours EN-EPS aggregation reached equilibrium, forming microscopic gels of ∼4–6 µm in size. In contrast, ENs only cause moderate assembly kinetic acceleration for A. angustus and P. tricornutum EPS samples. Our results indicate that the effects of ENs on EPS assembly kinetics mainly depend on the hydrophobic interactions of ENs with EPS polymers. The cycling mechanism of EPS is complex. Nonetheless, the change of EPS assembly kinetics induced by ENs can be considered as one potential disturbance to the marine carbon cycle. PMID:21811550

  4. Floodplain mesocosm system for studying environmental fate and effects of engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Schaumann, Gabriele E.; Steinmetz, Zacharias; Metreveli, George; Vogel, Hans-Jörg; Bundschuh, Mirco; Baumann, Thomas; Schulz, Ralf; Lang, Friederike; Seitz, Frank; Rosenfeldt, Ricki R.; Manz, Werner

    2015-04-01

    Once released into the environment, engineered inorganic nanoparticles (EINPs) will undergo chemical and physical transformation processes. The fate, ecotoxicological potential, and mobility of EINPs in environmental compartments will be influenced predominantly by their aging and current speciation status. In order to understand the aging mechanisms and impact of ENP transformations on their distribution and bioavailability in real environmental systems, mesocosm studies can be helpful. The INTERNANO floodplain mesocosm links aquatic and terrestrial aging phases in one system and has been conceived as near-natural test system to evaluate and further develop process understanding on aging and functioning of EINP in the aquatic-terrestrial transition zone. The mesocosm system is run with a pulse input function of EINP in order to investigate the response of the chemical, physico-chemical and biological systems over time. Immission into the soil system is performed via flooding events. The system is run with natural river water, natural repacked soil but with quartz sand as sediment phase. Convective water exchange between soil and aquatic compartments occurs at high water level. On this poster, we will present the design of the mesocosm system together with first findings on fate and biological effects of silver nanoparticles.

  5. Electrospun aligned PLGA and PLGA/gelatin nanofibers embedded with silica nanoparticles for tissue engineering.

    PubMed

    Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Ghaedi, Kamran; Salehi, Hossein; Arpanaei, Ayyoob

    2015-08-01

    Aligned poly lactic-co-glycolic acid (PLGA) and PLGA/gelatin nanofibrous scaffolds embedded with mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. The mean diameters of nanofibers were 641±24 nm for the pure PLGA scaffolds vs 418±85 nm and 267±58 nm for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The contact angle measurement results (102°±6.7 for the pure PLGA scaffold vs 81°±6.8 and 18°±8.7 for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively) revealed enhanced hydrophilicity of scaffolds upon incorporation of gelatin and MSNPs. Besides, embedding the scaffolds with MSNPs resulted in improved tensile mechanical properties. Cultivation of PC12 cells on the scaffolds demonstrated that introduction of MSNPs into PLGA and PLGA/gelatin matrices leads to the improved cell attachment and proliferation as well as long cellular processes. DAPI staining results indicated that cell proliferations on the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds were strikingly (nearly 2.5 and 3 folds, respectively) higher than that on the aligned pure PLGA scaffolds. These results suggest superior properties of silica nanoparticles-incorporated PLGA/gelatin eletrospun nanofibrous scaffolds for the stem cell culture and tissue engineering applications.

  6. Nano-composite scaffolds for bone tissue engineering containing silver nanoparticles: preparation, characterization and biological properties.

    PubMed

    Marsich, Eleonora; Bellomo, Francesca; Turco, Gianluca; Travan, Andrea; Donati, Ivan; Paoletti, Sergio

    2013-07-01

    In this study nano-composite scaffolds to be used as bone grafts have been endowed with antibacterial properties owing to the presence of silver nanoparticles. The alginate/hydroxyapatite composite scaffolds were prepared by internal gelation followed by a freeze-drying procedure to obtain a porous structure. The nanoparticles were prepared in presence of a lactose modified-chitosan and this colloidal solution was adsorbed on the scaffolds by exploiting electrostatic interactions. The adsorption and release of the silver from the composite scaffold was measured by ICP-AES and spectrofluorimetry measurements. Micro-computed tomography analysis of the scaffolds showed a homogeneous porous structure with average pore sizes of 341.5 μm and porosity of 80 %. In vitro biological tests (MTS and killing kinetics assays) demonstrated that silver does not affect the ability of the scaffolds to promote osteoblasts proliferation and that at the same time it exerts a strong bactericidal effect against both Gram+ and Gram- bacterial strains. Overall, the combined results indicate that these biocompatible antimicrobial scaffolds possess ideal characteristics for tissue engineering applications.

  7. Bisphosphonate-adsorbed ceramic nanoparticles increase bone formation in an injectable carrier for bone tissue engineering

    PubMed Central

    Cheng, Tegan L; Murphy, Ciara M; Ravarian, Roya; Dehghani, Fariba; Little, David G; Schindeler, Aaron

    2015-01-01

    Sucrose acetate isobutyrate (SAIB) is a sugar-based carrier. We have previously applied SAIB as a minimally invasive system for the co-delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) and found synergy when co-delivering zoledronic acid (ZA) and hydroxyapatite (HA) nanoparticles. Alternative bioceramics were investigated in a murine SAIB/rhBMP-2 injection model. Neither beta-tricalcium phosphate (TCP) nor Bioglass (BG) 45S5 had a significant effect on bone volume (BV) alone or in combination with the ZA. 14C-labelled ZA binding assays showed particle size and ceramic composition affected binding with nano-HA > micro-HA > TCP > BG. Micro-HA and nano-HA increased BV in a rat model of rhBMP-2/SAIB injection (+278% and +337%), and BV was further increased with ZA–adsorbed micro-HA and nano-HA (+530% and +889%). These data support the use of ZA–adsorbed nanoparticle-sized HA as an optimal additive for the SAIB/rhBMP-2 injectable system for bone tissue engineering. PMID:26668709

  8. Assessing Freshman Engineering Students' Understanding of Ethical Behavior.

    PubMed

    Henslee, Amber M; Murray, Susan L; Olbricht, Gayla R; Ludlow, Douglas K; Hays, Malcolm E; Nelson, Hannah M

    2017-02-01

    Academic dishonesty, including cheating and plagiarism, is on the rise in colleges, particularly among engineering students. While students decide to engage in these behaviors for many different reasons, academic integrity training can help improve their understanding of ethical decision making. The two studies outlined in this paper assess the effectiveness of an online module in increasing academic integrity among first semester engineering students. Study 1 tested the effectiveness of an academic honesty tutorial by using a between groups design with a Time 1- and Time 2-test. An academic honesty quiz assessed participants' knowledge at both time points. Study 2, which incorporated an improved version of the module and quiz, utilized a between groups design with three assessment time points. The additional Time 3-test allowed researchers to test for retention of information. Results were analyzed using ANCOVA and t tests. In Study 1, the experimental group exhibited significant improvement on the plagiarism items, but not the total score. However, at Time 2 there was no significant difference between groups after controlling for Time 1 scores. In Study 2, between- and within-group analyses suggest there was a significant improvement in total scores, but not plagiarism scores, after exposure to the tutorial. Overall, the academic integrity module impacted participants as evidenced by changes in total score and on specific plagiarism items. Although future implementation of the tutorial and quiz would benefit from modifications to reduce ceiling effects and improve assessment of knowledge, the results suggest such tutorial may be one valuable element in a systems approach to improving the academic integrity of engineering students.

  9. NANODEVICE: Novel Concepts, Methods, and Technologies for the Production of Portable, Easy-to-use Devices for the Measurement and Analysis of Airborne Engineered Nanoparticles in Workplace Air

    NASA Astrophysics Data System (ADS)

    Sirviö, Sari; Savolainen, Kai

    2011-07-01

    NANODEVICE is a research project funded by the European Commission in the context of the 7th Framework Programme. The duration is 48 months starting 1st of April 2009. Due to their unique properties, engineered nanoparticles (ENP) are now used for a myriad of novel applications, and have a great economic and technological importance. However, some of these properties, especially their surface reactivity, have raised health concerns due to their potential health effects. There is currently a shortage of field-worthy, cost-effective ways - especially in real time - for reliable assessment of exposure levels to ENP in workplace air. NANODEVICE will provide new information on the physico-chemical properties of engineered nanoparticles (ENP) and information about their toxicology. The main emphasis of the project is in the development of novel measuring devices to assess the exposure to ENP's from workplace air. The purpose of the project is also to promote the safe use of ENP through guidance, standards and education, implementing of safety objectives in ENP production and handling, and promotion of safety related collaborations through an international nanosafety forum. The main project goal is to develop innovative concepts and reliable methods for characterizing ENP in workplace air with novel, portable and easy-to-use devices suitable for workplaces.

  10. Organizational Cultural Assessment of the Energy Technology Engineering Center

    SciTech Connect

    Not Available

    1991-04-01

    An Organizational Cultural Assessment (OCA) was performed at the Energy Technology Engineering Center (ETEC) by administering an Organizational Culture Survey (OCS) that queried employees on the subjects of organizational culture, various aspects of communication, employee commitment to ETEC, work group cohesion, coordination of work, environmental, safety and health concerns, hazardous nature of work, and overall job satisfaction. A description of each of the scales used to assess these subjects is discussed below. The primary purpose of administering the survey was to attempt to measure, in a more quantitative and objective way the notion of organizational culture,'' that is, the values, attitudes, and beliefs of the individuals working within the organization. In particular, those aspects of the working environment which are believed to be important influences on the operations of a facility and on the safety issues relevant to the organization were assessed. This document describes the results of this survey. 9 refs., 22 figs., 7 tabs.

  11. Risk assessment and life prediction of complex engineering systems

    SciTech Connect

    Garcia, M.D.; Varma, R.; Heger, A.S.

    1996-03-01

    Many complex engineering systems will exceed their design life expectancy within the next 10 to 15 years. It is also expected that these systems must be maintained and operated beyond their design life. This paper presents a integrated approach for managing the risks associated with aging effects and predicting the residually expectancy these systems, The approach unifies risk assessment, enhanced surveillance and testing, and robust computational models to assess the risk, predict age, and develop a life-extension management procedure. It also relies on the state of the art in life-extension and risk assessment methods from the nuclear power industry. Borrowing from the developments in decision analysis, this approach should systematically identify the options available for managing the existing aging systems beyond their intended design life.

  12. An Updated Assessment of NASA Ultra-Efficient Engine Technologies

    NASA Technical Reports Server (NTRS)

    Tong Michael T.; Jones, Scott M.

    2005-01-01

    NASA's Ultra Efficient Engine Technology (UEET) project features advanced aeropropulsion technologies that include highly loaded turbomachinery, an advanced low-NOx combustor, high-temperature materials, and advanced fan containment technology. A probabilistic system assessment is performed to evaluate the impact of these technologies on aircraft CO2 (or equivalent fuel burn) and NOx reductions. A 300-passenger aircraft, with two 396-kN thrust (85,000-lb) engines is chosen for the study. The results show that a large subsonic aircraft equipped with the current UEET technology portfolio has very high probabilities of meeting the UEET minimum success criteria for CO2 reduction (-12% from the baseline) and LTO (landing and takeoff) NOx reductions (-65% relative to the 1996 International Civil Aviation Organization rule).

  13. Tiger Team assessment of the Idaho National Engineering Laboratory

    SciTech Connect

    Not Available

    1991-08-01

    This report documents the Tiger Team Assessment of the Idaho National Engineering Laboratory (INEL) located in Idaho Falls, Idaho. INEL is a multiprogram, laboratory site of the US Department of Energy (DOE). Overall site management is provided by the DOE Field Office, Idaho; however, the DOE Field Office, Chicago has responsibility for the Argonne National Laboratory-West facilities and operations through the Argonne Area Office. In addition, the Idaho Branch Office of the Pittsburgh Naval Reactors Office has responsibility for the Naval Reactor Facility (NRF) at the INEL. The assessment included all DOE elements having ongoing program activities at the site except for the NRF. In addition, the Safety and Health Subteam did not review the Westinghouse Idaho Nuclear Company, Inc. facilities and operations. The Tiger Team Assessment was conducted from June 17 to August 2, 1991, under the auspices of the Office of Special Projects, Office of the Assistant Secretary for Environment, Safety and Health, Headquarters, DOE. The assessment was comprehensive, encompassing environmental, safety, and health (ES H) disciplines; management; and contractor and DOE self-assessments. Compliance with applicable federal, state, and local regulations; applicable DOE Orders; best management practices; and internal INEL site requirements was assessed. In addition, an evaluation of the adequacy and effectiveness of the DOE and the site contractors management of ES H/quality assurance programs was conducted.

  14. Novel magnetic fibrin hydrogel scaffolds containing thrombin and growth factors conjugated iron oxide nanoparticles for tissue engineering

    PubMed Central

    Ziv-Polat, Ofra; Skaat, Hadas; Shahar, Abraham; Margel, Shlomo

    2012-01-01

    Novel tissue-engineered magnetic fibrin hydrogel scaffolds were prepared by the interaction of thrombin-conjugated iron oxide magnetic nanoparticles with fibrinogen. In addition, stabilization of basal fibroblast growth factor (bFGF) was achieved by the covalent and physical conjugation of the growth factor to the magnetic nanoparticles. Adult nasal olfactory mucosa (NOM) cells were seeded in the transparent fibrin scaffolds in the absence or presence of the free or conjugated bFGF-iron oxide nanoparticles. The conjugated bFGF enhanced significantly the growth and differentiation of the NOM cells in the fibrin scaffolds, compared to the same or even five times higher concentration of the free bFGF. In the presence of the bFGF-conjugated magnetic nanoparticles, the cultured NOM cells proliferated and formed a three-dimensional interconnected network composed mainly of tapered bipolar cells. The magnetic properties of these matrices are due to the integration of the thrombin- and bFGF-conjugated magnetic nanoparticles within the scaffolds. The magnetic properties of these scaffolds may be used in future work for various applications, such as magnetic resonance visualization of the scaffolds after implantation and reloading the scaffolds via magnetic forces with bioactive agents, eg, growth factors bound to the iron oxide magnetic nanoparticles. PMID:22419873

  15. Idaho National Engineering Laboratory Sewer System Upgrade Project. Environmental Assessment

    SciTech Connect

    Not Available

    1994-04-01

    The Department of Energy (DOE) has prepared an environmental assessment for a proposed Sewer System Upgrade Project at the Idaho National Engineering Laboratory (INEL) near Idaho Falls, Idaho. The proposed action would include activities conducted at the Central Facilities Area, Test Reactor Area, and the Containment Test Facility at the Test Area North at INEL. The proposed action would consist of replacing or remodeling the existing sewage treatment plants at the Central Facilities Area, Test Reactor Area, and Containment Test Facility. Also, a new sewage testing laboratory would be constructed at the Central Facilities Area. Finally, the proposed action would include replacing, repairing, and/or adding sewer lines in areas where needed.

  16. Review of key factors controlling engineered nanoparticle transport in porous media.

    PubMed

    Wang, Mei; Gao, Bin; Tang, Deshan

    2016-11-15

    Nanotechnology, an emerging technology, has witnessed rapid development in production and application. Engineered nanomaterials revolutionize the industry due to their unique structure and superior performance. The release of engineered nanoparticles (ENPs) into the environment, however, may pose risks to the environment and public health. To advance current understanding of environmental behaviors of ENPs, this work provides an introductory overview of ENP fate and transport in porous media. It systematically reviews the key factors controlling their fate and transport in porous media. It first provides a brief overview of common ENPs in the environment and their sources. The key factors that govern ENP transport in porous media are then categorized into three groups: (1) nature of ENPs affecting their transport in porous media, (2) nature of porous media affecting ENP transport, and (3) nature of flow affecting ENP transport in porous media. In each group, findings in recent literature on the specific governing factors of ENP transport in porous media are discussed in details. Finally, this work concludes with remarks on the importance of ENP transport in porous media and directions for future research.

  17. Research unit INTERNANO: Mobility, aging and functioning of engineered inorganic nanoparticles at the aquatic-terrestrial interface

    NASA Astrophysics Data System (ADS)

    Schaumann, Gabriele Ellen; Metreveli, George; Baumann, Thomas; Klitzke, Sondra; Lang, Friederike; Manz, Werner; Nießner, Reinhard; Schulz, Ralf; Vogel, Hans-Jörg

    2013-04-01

    Engineered inorganic nanoparticles (EINP) are expected to pass the wastewater-river-topsoil-groundwater pathway. Despite their increasing release, the processes governing the EINP aging and the changes in functionality in the environment are up to now largely unknown. The objective of the interdisciplinary research unit INTERNANO funded by the DFG is to identify the processes relevant for the fate of EINP and EINP-associated pollutants in the interfacial zone between aquatic and terrestrial ecosystems. The research unit consists of six subprojects and combines knowledge from aquatic and terrestrial sciences as well as from microbiology, ecotoxicology, physicochemistry, soil chemistry and soil physics. For the identification of key processes we will consider compartment specific flow conditions, physicochemistry and biological activity. Situations representative for a floodplain system are simulated using micromodels (μm scale) as well as incubation, soil column and joint laboratory stream microcosm experiments. These results will be transferred to a joint aquatic-terrestrial model system on EINP aging, transport and functioning across the aquatic-terrestrial transition zone. EINP isolation and characterization will be carried out via a combination of chromatographic, light scattering and microscopic methods including dynamic light scattering, elemental analysis, hydrodynamic radius chromatography, field flow fractionation as well as atomic force microscopy, Raman microscopy and electron microscopy. INTERNANO generates fundamental aquatic-terrestrial process knowledge, which will help to evaluate the environmental significance of the EINP at aquatic-terrestrial interfaces. Thus, INTERNANO provides a scientific basis to assess and predict the environmental impact of EINP release into the environment.

  18. A comprehensive environmental assessment approach to engineered nanomaterials.

    PubMed

    Davis, J Michael

    2013-01-01

    The anticipated benefits of engineered nanomaterials (ENMs) should be weighed against their possible negative impacts. Comprehensive environmental assessment (CEA) provides a means of evaluating such trade-offs in a holistic and systematic manner. CEA consists of both a framework for organizing information and a process for using collective judgment to identify and prioritize the issues presented by ENMs. As a meta-assessment approach, CEA is designed to assist both research planners and risk managers by building on various assessment and analytic tools used by risk assessors. Given the immature state of the science for ENMs, CEA is currently being primarily used for prioritizing research directions. Therefore, highlights of case studies of selected ENM applications are presented to illustrate how CEA has been applied thus far to help guide research efforts to support future assessment efforts. In addition, CEA is discussed in relation to topical subjects, such as sustainability, transparency, and stakeholder engagement. Finally, comparisons to other life cycle-based assessment approaches directed at ENMs are noted.

  19. Indicators and metrics for the assessment of climate engineering

    NASA Astrophysics Data System (ADS)

    Oschlies, A.; Held, H.; Keller, D.; Keller, K.; Mengis, N.; Quaas, M.; Rickels, W.; Schmidt, H.

    2017-01-01

    Selecting appropriate indicators is essential to aggregate the information provided by climate model outputs into a manageable set of relevant metrics on which assessments of climate engineering (CE) can be based. From all the variables potentially available from climate models, indicators need to be selected that are able to inform scientists and society on the development of the Earth system under CE, as well as on possible impacts and side effects of various ways of deploying CE or not. However, the indicators used so far have been largely identical to those used in climate change assessments and do not visibly reflect the fact that indicators for assessing CE (and thus the metrics composed of these indicators) may be different from those used to assess global warming. Until now, there has been little dedicated effort to identifying specific indicators and metrics for assessing CE. We here propose that such an effort should be facilitated by a more decision-oriented approach and an iterative procedure in close interaction between academia, decision makers, and stakeholders. Specifically, synergies and trade-offs between social objectives reflected by individual indicators, as well as decision-relevant uncertainties should be considered in the development of metrics, so that society can take informed decisions about climate policy measures under the impression of the options available, their likely effects and side effects, and the quality of the underlying knowledge base.

  20. Research and engineering assessment of biological solubilization of phosphate

    SciTech Connect

    Rogers, R.D.; McIlwain, M.E.; Losinski, S.J.; Taylor, D.D.

    1993-03-01

    This research and engineering assessment examined a microbial phosphate solubilization process as a method of recovering phosphate from phosphorus containing ore compared to the existing wet acid and electric arc methods. A total of 860 microbial isolates, collected from a range of natural environments were tested for their ability to solubilize phosphate from rock phosphate. A bacterium (Pseudomonas cepacia) was selected for extensive characterization and evaluation of the mechanism of phosphate solubilization and of process engineering parameters necessary to recover phosphate from rock phosphate. These studies found that concentration of hydrogen ion and production of organic acids arising from oxidation of the carbon source facilitated microbial solubilization of both pure chemical insoluble phosphate compounds and phosphate rock. Genetic studies found that phosphate solubilization was linked to an enzyme system (glucose dehydrogenase). Process-related studies found that a critical solids density of 1% by weight (ore to liquid) was necessary for optimal solubilization. An engineering analysis evaluated the cost and energy requirements for a 2 million ton per year sized plant, whose size was selected to be comparable to existing wet acid plants.

  1. An Assessment of Research-Doctorate Programs in the United States: Engineering.

    ERIC Educational Resources Information Center

    Jones, Lyle V., Ed.; And Others

    The quality of doctoral-level chemical engineering (N=79), civil engineering (N=74), electrical engineering (N=91), and mechanical engineering (N=82) programs at United States universities was assessed, using 16 measures. These measures focused on variables related to: (1) program size; (2) characteristics of graduates; (3) reputational factors…

  2. Onboard measurements of nanoparticles from a SCR-equipped marine diesel engine.

    PubMed

    Hallquist, Åsa M; Fridell, Erik; Westerlund, Jonathan; Hallquist, Mattias

    2013-01-15

    In this study nanoparticle emissions have been characterized onboard a ship with focus on number, size, and volatility. Measurements were conducted on one of the ship's four main 12,600 kW medium-speed diesel engines which use low sulfur marine residual fuel and have a Selective Catalytic Reduction (SCR) system for NO(X) abatement. The particles were measured after the SCR with an engine exhaust particle sizer spectrometer (EEPS), giving particle number and mass distributions in the size range of 5.6-560 nm. The thermal characteristics of the particles were analyzed using a volatility tandem DMA system (VTDMA). A dilution ratio of 450-520 was used which is similar to the initial real-world dilution. At a stable engine load of 75% of the maximum rated power, and after dilution and cooling of the exhaust gas, there was a bimodal number size distribution, with a major peak at ∼10 nm and a smaller peak at around 30-40 nm. The mass distribution peaked around 20 nm and at 50-60 nm. The emission factor for particle number, EF(PN), for an engine load of 75% in the open-sea was found to be 10.4 ± 1.6 × 10(16) (kg fuel)(-1) and about 50% of the particles by number were found to have a nonvolatile core at 250 °C. Additionally, 20 nm particles consist of ∼40% of nonvolatile material by volume (evaporative temperature 250 °C), while the particles with a particle diameter <10 nm evaporate completely at a temperature of 130-150 °C. Emission factors for NO(X), CO, and CO(2) for an engine load of 75% in the open-sea were determined to 4.06 ± 0.3 g (kg fuel)(-1), 2.15 ± 0.06 g (kg fuel)(-1), and 3.23 ± 0.08 kg (kg fuel)(-1), respectively. This work contributes to an improved understanding of particle emissions from shipping using modern pollution reduction measures such as SCR and fuel with low sulfur content.

  3. Development and Testing of Assessment Instruments for Multidisciplinary Engineering Capstone Design Courses

    ERIC Educational Resources Information Center

    Gerlick, Robert Edward

    2010-01-01

    The research presented in this manuscript was focused on the development of assessments for engineering design outcomes. The primary goal was to support efforts by the Transferrable Integrated Design Engineering Education (TIDEE) consortium in developing assessment instruments for multidisciplinary engineering capstone courses. Research conducted…

  4. Safety and efficacy of composite collagen-silver nanoparticle hydrogels as tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Alarcon, Emilio I.; Udekwu, Klas I.; Noel, Christopher W.; Gagnon, Luke B.-P.; Taylor, Patrick K.; Vulesevic, Branka; Simpson, Madeline J.; Gkotzis, Spyridon; Islam, M. Mirazul; Lee, Chyan-Jang; Richter-Dahlfors, Agneta; Mah, Thien-Fah; Suuronen, Erik J.; Scaiano, Juan C.; Griffith, May

    2015-11-01

    The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and other inflammation markers (CCL24, sTNFR-2, and TIMP1). Finally, an analysis of silver contents in implanted mice showed that silver accumulation primarily occurred within the tissue surrounding the implant.The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and

  5. Characterizing the Transport of a Novel, Engineered Nanoparticle for Use in Remediation of Hydrophobic Contaminants

    NASA Astrophysics Data System (ADS)

    Sanders, J. E.; Miller, G. R.

    2015-12-01

    Magnetic shell crosslinked knedel-like nanoparticles (MSCKs) were originally engineered to aid in the cleanup of oil spills. These polymeric particles are spherical and approximately 70 nm in diameter. MSCKs have a hydrophobic shell and hydrophilic core which encapsulates suspended iron oxide nanoparticles, rendering them magnetic. MSCKs operate like discrete surfactant packets: increasing the mobility and apparent solubility of hydrophobic species, but do so within the confines of discrete particles which can then be recovered by filtration or magnetic removal. MSCKs accomplish this via sequestration of hydrophobic species from through the hydrophilic shell and into the hydrophobic core where hydrocarbon contaminants are entropically stabilized. In batch reactor testing, MSCKs have been shown to sequester crude oil up to ten times their mass (1000 mg of oil per 100 mg of MSCKs). This study examines the transport characteristics and contaminant sequestration capabilities of MSCKs in saturated porous media, in order to establish their potential for use in groundwater remediation. Baseline MSCK transport parameters were determined via one dimensional impulse column experiments. MSCKs were readily transported in saturated sand, with an average recovery rate of 99%. In the presence of 10% clay particles, recovery was reduced to 68%. MSCKs were able to completely sequester an aqueous phase pollutant (8.7 mg/L m-xylene), although it further reduced their recovery rate to 61% in sand and 53% in clay. The presence of a free phase contaminant (5% of pore space occupied by mineral oil) reduced MSCKs recovery in sand to 53%. The MSCKs recovered in the effluent had sequestered the mineral at ratios far below their capability (3-10 mg of oil per 100 mg of MSCKs). Overall, this study indicated that MSCKs show a number of promising attributes for use in remediation. However, further manipulation of their chemical and morphological properties is needed, with the objective of

  6. Signal Processing Methods for Liquid Rocket Engine Combustion Stability Assessments

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy; Lee, Erik; Hulka, James R.; Casiano, Matthew

    2011-01-01

    The J2X Gas Generator engine design specifications include dynamic, spontaneous, and broadband combustion stability requirements. These requirements are verified empirically based high frequency chamber pressure measurements and analyses. Dynamic stability is determined with the dynamic pressure response due to an artificial perturbation of the combustion chamber pressure (bomb testing), and spontaneous and broadband stability are determined from the dynamic pressure responses during steady operation starting at specified power levels. J2X Workhorse Gas Generator testing included bomb tests with multiple hardware configurations and operating conditions, including a configuration used explicitly for engine verification test series. This work covers signal processing techniques developed at Marshall Space Flight Center (MSFC) to help assess engine design stability requirements. Dynamic stability assessments were performed following both the CPIA 655 guidelines and a MSFC in-house developed statistical-based approach. The statistical approach was developed to better verify when the dynamic pressure amplitudes corresponding to a particular frequency returned back to pre-bomb characteristics. This was accomplished by first determining the statistical characteristics of the pre-bomb dynamic levels. The pre-bomb statistical characterization provided 95% coverage bounds; these bounds were used as a quantitative measure to determine when the post-bomb signal returned to pre-bomb conditions. The time for post-bomb levels to acceptably return to pre-bomb levels was compared to the dominant frequency-dependent time recommended by CPIA 655. Results for multiple test configurations, including stable and unstable configurations, were reviewed. Spontaneous stability was assessed using two processes: 1) characterization of the ratio of the peak response amplitudes to the excited chamber acoustic mode amplitudes and 2) characterization of the variability of the peak response

  7. Tiger Team assessment of the Idaho National Engineering Laboratory

    SciTech Connect

    McKenzie, Barbara J.; West, Stephanie G.; Jones, Olga G.; Kerr, Dorothy A.; Bieri, Rita A.; Sanderson, Nancy L.

    1991-08-01

    The purpose of the Safety and Health (S H) Subteam assessment was to determine the effectiveness of representative safety and health programs at the Idaho National Engineering Laboratory (INEL) site. Four Technical Safety Appraisal (TSA) Teams were assembled for this purpose by the US Department of Energy (DOE), Deputy Assistant Secretary for Safety and Quality Assurance, Office of Safety Appraisals (OSA). Team No. 1 reviewed EG G Idaho, Inc. (EG G Idaho) and the Department of Energy Field Office, Idaho (ID) Fire Department. Team No. 2 reviewed Argonne National Laboratory-West (ANL-W). Team No. 3 reviewed selected contractors at the INEL; specifically, Morrison Knudsen-Ferguson of Idaho Company (MK-FIC), Protection Technology of Idaho, Inc. (PTI), Radiological and Environmental Sciences Laboratory (RESL), and Rockwell-INEL. Team No. 4 provided an Occupational Safety and Health Act (OSHA)-type compliance sitewide assessment of INEL. The S H Subteam assessment was performed concurrently with assessments conducted by Environmental and Management Subteams. Performance was appraised in the following technical areas: Organization and Administration, Quality Verification, Operations, Maintenance, Training and Certification, Auxiliary Systems, Emergency Preparedness, Technical Support, Packaging and Transportation, Nuclear Criticality Safety, Security/Safety Interface, Experimental Activities, Site/Facility Safety Review, Radiological Protection, Personnel Protection, Worker Safety and Health (OSHA) Compliance, Fire Protection, Aviation Safety, Medical Services, and Firearms Safety.

  8. Tiger Team assessment of the Idaho National Engineering Laboratory

    SciTech Connect

    Goldberg, Edward S.; Keating, John J.

    1991-08-01

    The Management Subteam conducted a management assessment of Environment, Safety, and Health (ES H) programs and their implementation of Idaho National Engineering Laboratory (INEL). The objectives of the assessment were to: (1) evaluate the effectiveness of existing management functions and processes in terms of ensuring environmental compliance, and the health and safety of workers and the general public; and (2) identify probable root causes for ES H findings and concerns. Organizations reviewed were DOE-Headquarters: DOE Field Offices, Chicago (CH) and Idaho (ID); Argonne Area Offices, East (AAO-E) and West (AAO-W); Radiological and Environmental Sciences Laboratory (RESL); Argonne National Laboratory (ANL); EG G Idaho, Inc. (EG G); Westinghouse Idaho Nuclear Company, Inc. (WINCO); Rockwell-INEL; MK-Ferguson of Idaho Company (MK-FIC); and Protection Technology of Idaho, Inc. (PTI). The scope of the assessment covered the following ES H management issues: policies and procedures; roles, responsibilities, and authorities; management commitment; communication; staff development, training, and certification; recruitment; compliance management; conduct of operations; emergency planning and preparedness; quality assurance; self assessment; oversight activities; and cost plus award fee processes.

  9. Endogenous allergens in the regulatory assessment of genetically engineered crops.

    PubMed

    Graf, Lynda; Hayder, Hikmat; Mueller, Utz

    2014-11-01

    A scientific approach to the assessment of foods derived from genetically engineered (GE) crops is critical to maintaining objectivity and public confidence in regulatory decisions. Principles developed at the international level support regulators and enable robust and transparent safety assessments. A comparison of key constituents in the GE crop with a suitable comparator is an important element of an assessment. In Europe, endogenous allergens would be included in the comparative analysis, however this approach has been hindered by technical limitations on the ability to accurately measure identified allergenic proteins. Over recent years, improved proteomic methods have enabled researchers to focus on major allergenic proteins in conventional food crops, as information on natural variability is largely lacking. Emerging data for soybean indicate that variability in levels of major allergens already in the food supply is broad. This raises questions about the biological interpretation of differences between a GE plant and its conventional counterpart, in particular, whether any conclusions about altered allergenicity could be inferred. This paper discusses the scientific justification for requiring proteomic analysis of endogenous allergens as part of the evaluation. Ongoing scientific review and corresponding international discussion are integral to ensuring that data requirements address legitimate risk assessment questions.

  10. Titanium dioxide nanoparticles: occupational exposure assessment in the photocatalytic paving production

    NASA Astrophysics Data System (ADS)

    Spinazzè, Andrea; Cattaneo, Andrea; Limonta, Marina; Bollati, Valentina; Bertazzi, Pier Alberto; Cavallo, Domenico M.

    2016-06-01

    Limited data are available regarding occupational exposure assessment to nano-sized titanium dioxide (nano-TiO2). The objective of this study is to assess the occupational exposure of workers engaged in the application of nano-TiO2 onto concrete building materials, by means of a multi-metric approach (mean diameter, number, mass and surface area concentrations). The measurement design consists of the combined use of (i) direct-reading instruments to evaluate the total particle number concentrations relative to the background concentration and the mean size-dependent characteristics of particles (mean diameter and surface area concentration) and to estimate the 8-h time-weighted average (8-h TWA) exposure to nano-TiO2 for workers involved in different working tasks; and (ii) filter-based air sampling, used for the determination of size-resolved particle mass concentrations. A further estimation was performed to obtain the mean 8-h TWA exposure values expressed as mass concentrations (µg nano-TiO2/m3). The multi-metric characterization of occupational exposure to nano-TiO2 was significantly different both for different work environments and for each work task. Generally, workers were exposed to engineered nanoparticles (ENPs; <100 nm) mean levels lower than the recommended reference values and proposed occupational exposure limits (40,000 particle/cm3; 300 µg/m3) and relevant exposures to peak concentration were not likely to be expected. The estimated 8-h TWA exposure showed differences between the unexposed and exposed subjects. For these last, further differences were defined between operators involved in different work tasks. This study provides information on nano-TiO2 number and mass concentration, size distribution, particles diameter and surface area concentrations, which were used to obtain work shift-averaged exposures.

  11. Aeronautics and Space Engineering Board: Aeronautics Assessment Committee

    NASA Technical Reports Server (NTRS)

    1977-01-01

    High temperature engine materials, fatigue and fracture life prediction, composite materials, propulsion noise pollution, propulsion components, full-scale engine research, V/STOL propulsion, advanced engine concepts, and advanced general aviation propulsion research were discussed.

  12. Assessment of the In Vivo Toxicity of Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Shiun; Hung, Yao-Ching; Liau, Ian; Huang, G. Steve

    2009-08-01

    The environmental impact of nanoparticles is evident; however, their toxicity due to their nanosize is rarely discussed. Gold nanoparticles (GNPs) may serve as a promising model to address the size-dependent biological response to nanoparticles because they show good biocompatibility and their size can be controlled with great precision during their chemical synthesis. Naked GNPs ranging from 3 to 100 nm were injected intraperitoneally into BALB/C mice at a dose of 8 mg/kg/week. GNPs of 3, 5, 50, and 100 nm did not show harmful effects; however, GNPs ranging from 8 to 37 nm induced severe sickness in mice. Mice injected with GNPs in this range showed fatigue, loss of appetite, change of fur color, and weight loss. Starting from day 14, mice in this group exhibited a camel-like back and crooked spine. The majority of mice in these groups died within 21 days. Injection of 5 and 3 nm GNPs, however, did not induce sickness or lethality in mice. Pathological examination of the major organs of the mice in the diseased groups indicated an increase of Kupffer cells in the liver, loss of structural integrity in the lungs, and diffusion of white pulp in the spleen. The pathological abnormality was associated with the presence of gold particles at the diseased sites, which were verified by ex vivo Coherent anti-Stoke Raman scattering microscopy. Modifying the surface of the GNPs by incorporating immunogenic peptides ameliorated their toxicity. This reduction in the toxicity is associated with an increase in the ability to induce antibody response. The toxicity of GNPs may be a fundamental determinant of the environmental toxicity of nanoparticles.

  13. An organizational cultural assessment of the Energy Technology Engineering Center

    SciTech Connect

    Haber, S.B.; Crouch, D.A.

    1991-04-01

    An Organizational Cultural Assessment (OCA) was performed at the Energy Technology Engineering Center (ETEC) by administering an Organizational Culture Survey (OCS) that queried employees on the subjects of organizational culture, various species of communication, employee commitment to ETEC, work group cohesion, coordination of work, environmental, safety and health concerns, hazardous nature of work, and overall job satisfaction. A description of each of the scales used to assess these subjects is discussed. The primary purpose of administering the survey was to attempt to measure, in a more quantitative and objective way the notion of organizational culture, '' that is, the values, attitudes, and beliefs of the individuals working within the organization. In particular, those aspects of the working environment which are believed to be important influences on the operations of a facility and on the safety issues relevant to the organization were assessed. In addition, by conducting a survey, a broad sampling of the individuals in the organization can be obtained. This is especially important when the survey is utilized in conjunction with an assessment or inspection team which typically has only a limited amount of resources to address many issues. The OCS provides a broad, but more comprehensive picture of the organization by querying a much larger number of individuals than could be reached through the assessment team alone. Finally, the OCS provides a descriptive profile of the organization at one point in time. This profile can then can be used as a baseline point against which comparisons of other points in time can be made. Such comparisons may prove valuable and would help to assess changes in the organizational culture. Comparisons of the profiles can also be made across similar facilities. 9 refs., 22 figs., 6 tabs.

  14. Critical Assessment of the Evidence for Striped Nanoparticles

    PubMed Central

    Stirling, Julian; Lekkas, Ioannis; Sweetman, Adam; Djuranovic, Predrag; Guo, Quanmin; Pauw, Brian; Granwehr, Josef; Lévy, Raphaël; Moriarty, Philip

    2014-01-01

    There is now a significant body of literature which reports that stripes form in the ligand shell of suitably functionalised Au nanoparticles. This stripe morphology has been proposed to strongly affect the physicochemical and biochemical properties of the particles. We critique the published evidence for striped nanoparticles in detail, with a particular focus on the interpretation of scanning tunnelling microscopy (STM) data (as this is the only technique which ostensibly provides direct evidence for the presence of stripes). Through a combination of an exhaustive re-analysis of the original data, in addition to new experimental measurements of a simple control sample comprising entirely unfunctionalised particles, we show that all of the STM evidence for striped nanoparticles published to date can instead be explained by a combination of well-known instrumental artefacts, or by issues with data acquisition/analysis protocols. We also critically re-examine the evidence for the presence of ligand stripes which has been claimed to have been found from transmission electron microscopy, nuclear magnetic resonance spectroscopy, small angle neutron scattering experiments, and computer simulations. Although these data can indeed be interpreted in terms of stripe formation, we show that the reported results can alternatively be explained as arising from a combination of instrumental artefacts and inadequate data analysis techniques. PMID:25402426

  15. Continuous 3-day exposure assessment of workplace manufacturing silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Lee, Ji Hyun; Ahn, Kangho; Kim, Sun Man; Jeon, Ki Soo; Lee, Jong Seong; Yu, Il Je

    2012-09-01

    With the increased production and widespread use of nanomaterials, human and environmental exposure to nanomaterials is inevitably increasing. Therefore, this study monitored the possible nanoparticle exposure at a workplace that manufactures silver nanoparticles. To estimate the potential exposure of workers, personal sampling, area monitoring, and real-time monitoring were conducted over 3 days using a scanning mobility particle sizer and dust monitor at a workplace where the workers handle nanomaterials. The area sampling concentrations obtained from the injection room showed the highest concentration, ranging from 0.00501 to 0.28873 mg/m3. However, apart from the injection room, none of the area samplings obtained from other locations showed a concentration higher than 0.0013 mg/m3. Meanwhile, the personal sampling concentrations ranged from 0.00004 to 0.00243 mg/m3 over the 3 days of sampling, which was much lower than the silver TLV. The particle number concentrations at the silver nanoparticle manufacturing workplace were 911,170 (1st day), 1,631,230 (2nd day), and 1,265,024 (3rd day) particles/cm3 with a size range of 15-710.5 nm during the operation of the reactor, while the concentration decreased to 877,364.9 (1st day), 492,732 (2nd day), and 344,343 (3rd day) particles/cm3 when the reactor was stopped.

  16. Critical assessment of the evidence for striped nanoparticles.

    PubMed

    Stirling, Julian; Lekkas, Ioannis; Sweetman, Adam; Djuranovic, Predrag; Guo, Quanmin; Pauw, Brian; Granwehr, Josef; Lévy, Raphaël; Moriarty, Philip

    2014-01-01

    There is now a significant body of literature which reports that stripes form in the ligand shell of suitably functionalised Au nanoparticles. This stripe morphology has been proposed to strongly affect the physicochemical and biochemical properties of the particles. We critique the published evidence for striped nanoparticles in detail, with a particular focus on the interpretation of scanning tunnelling microscopy (STM) data (as this is the only technique which ostensibly provides direct evidence for the presence of stripes). Through a combination of an exhaustive re-analysis of the original data, in addition to new experimental measurements of a simple control sample comprising entirely unfunctionalised particles, we show that all of the STM evidence for striped nanoparticles published to date can instead be explained by a combination of well-known instrumental artefacts, or by issues with data acquisition/analysis protocols. We also critically re-examine the evidence for the presence of ligand stripes which has been claimed to have been found from transmission electron microscopy, nuclear magnetic resonance spectroscopy, small angle neutron scattering experiments, and computer simulations. Although these data can indeed be interpreted in terms of stripe formation, we show that the reported results can alternatively be explained as arising from a combination of instrumental artefacts and inadequate data analysis techniques.

  17. POLLUTION PREVENTION OPPORTUNITY ASSESSMENT OF THE U.S. ARMY CORPS OF ENGINEERS CIVIL WORKS FACILITIES

    EPA Science Inventory

    The Pollution Prevention Opportunity Assessments (PPOA) summarized here were conducted at the following representative Army Corps of Engineers (USAGE) Civil Works facilities: Pittsburgh Engineering Warehouse and Repair Station (PEWARS) and Emsworth Locks and Dams in Pittsburgh, P...

  18. Poly-adenine-based programmable engineering of gold nanoparticles for highly regulated spherical DNAzymes

    NASA Astrophysics Data System (ADS)

    Zhu, Dan; Pei, Hao; Chao, Jie; Su, Shao; Aldalbahi, Ali; Rahaman, Mostafizur; Wang, Lihua; Wang, Lianhui; Huang, Wei; Fan, Chunhai; Zuo, Xiaolei

    2015-11-01

    Enzyme complexes are assembled at the two-dimensional lipid membrane or prearranged on three-dimensional scaffolding proteins to regulate their catalytic activity in cells. Inspired by nature, we have developed gold nanoparticle-based spherical DNAzymes (SNAzymes) with programmably engineered activities by exploiting poly-adenine (polyA)-Au interactions. In a SNAzyme, AuNPs serve as the metal core, which is decorated with a functional shell of DNAzymes. Conventional thiolated DNAzyme-based assembly leads to disordered structures with suppressed activity. In contrast, by using an anchoring block of polyA tails, we find that the activity of SNAzymes can be programmably regulated. By using a polyA30 tail, SNAzymes demonstrated remarkably enhanced binding affinity compared to the thiolated DNAzyme-based assembly (~75-fold) or individual DNAzymes in the solution phase (~10-fold). More significantly, this increased affinity is directly translated to the sensitivity improvement in the SNAzyme-based lead sensor. Hence, this design of SNAzymes may provide new opportunities for developing biosensors and bioimaging probes for theranostic applications.Enzyme complexes are assembled at the two-dimensional lipid membrane or prearranged on three-dimensional scaffolding proteins to regulate their catalytic activity in cells. Inspired by nature, we have developed gold nanoparticle-based spherical DNAzymes (SNAzymes) with programmably engineered activities by exploiting poly-adenine (polyA)-Au interactions. In a SNAzyme, AuNPs serve as the metal core, which is decorated with a functional shell of DNAzymes. Conventional thiolated DNAzyme-based assembly leads to disordered structures with suppressed activity. In contrast, by using an anchoring block of polyA tails, we find that the activity of SNAzymes can be programmably regulated. By using a polyA30 tail, SNAzymes demonstrated remarkably enhanced binding affinity compared to the thiolated DNAzyme-based assembly (~75-fold) or

  19. Changing the dose metric for inhalation toxicity studies: short-term study in rats with engineered aerosolized amorphous silica nanoparticles.

    PubMed

    Sayes, Christie M; Reed, Kenneth L; Glover, Kyle P; Swain, Keith A; Ostraat, Michele L; Donner, E Maria; Warheit, David B

    2010-03-01

    Inhalation toxicity and exposure assessment studies for nonfibrous particulates have traditionally been conducted using particle mass measurements as the preferred dose metric (i.e., mg or microg/m(3)). However, currently there is a debate regarding the appropriate dose metric for nanoparticle exposure assessment studies in the workplace. The objectives of this study were to characterize aerosol exposures and toxicity in rats of freshly generated amorphous silica (AS) nanoparticles using particle number dose metrics (3.7 x 10(7) or 1.8 x 10(8) particles/cm(3)) for 1- or 3-day exposures. In addition, the role of particle size (d(50) = 37 or 83 nm) on pulmonary toxicity and genotoxicity endpoints was assessed at several postexposure time points. A nanoparticle reactor capable of producing, de novo synthesized, aerosolized amorphous silica nanoparticles for inhalation toxicity studies was developed for this study. SiO(2) aerosol nanoparticle synthesis occurred via thermal decomposition of tetraethylorthosilicate (TEOS). The reactor was designed to produce aerosolized nanoparticles at two different particle size ranges, namely d(50) = approximately 30 nm and d(50) = approximately 80 nm; at particle concentrations ranging from 10(7) to 10(8) particles/cm(3). AS particle aerosol concentrations were consistently generated by the reactor. One- or 3-day aerosol exposures produced no significant pulmonary inflammatory, genotoxic, or adverse lung histopathological effects in rats exposed to very high particle numbers corresponding to a range of mass concentrations (1.8 or 86 mg/m(3)). Although the present study was a short-term effort, the methodology described herein can be utilized for longer-term inhalation toxicity studies in rats such as 28-day or 90-day studies. The expansion of the concept to subchronic studies is practical, due, in part, to the consistency of the nanoparticle generation method.

  20. Assessment of Nanoparticle Exposure in Nanosilica Handling Process: Including Characteristics of Nanoparticles Leaking from a Vacuum Cleaner

    PubMed Central

    KIM, Boowook; KIM, Hyunwook; YU, Il Je

    2013-01-01

    Nanosilica is one of the most widely used nanomaterials across the world. However, their assessment data on the occupational exposure to nanoparticles is insufficient. The present study performed an exposure monitoring in workplace environments where synthetic powders are prepared using fumed nanosilica. Furthermore, after it was observed during exposure monitoring that nanoparticles were emitted through leakage in a vacuum cleaner (even with a HEPA-filter installed in it), the properties of the leaked nanoparticles were also investigated. Workers were exposed to high-concentration nanosilica emitted into the air while pouring it into a container or transferring the container. The use of a vacuum cleaner with a leak (caused by an inadequate sealing) was found to be the origin of nanosilica dispersion in the indoor air. While the particle size of the nanosilica that emitted into the air (during the handling of nanosilica by a worker) was mostly over 100 nm or several microns (µm) due to the coagulation of particles, the size of nanosilica that leaked out of vacuum cleaner was almost similar to the primary size (mode diameter 11.5 nm). Analysis of area samples resulted in 20% (60% in terms of peak concentration) less than the analysis of the personals sample. PMID:24366536

  1. Assessment of nanoparticle exposure in nanosilica handling process: including characteristics of nanoparticles leaking from a vacuum cleaner.

    PubMed

    Kim, Boowook; Kim, Hyunwook; Yu, Il Je

    2014-01-01

    Nanosilica is one of the most widely used nanomaterials across the world. However, their assessment data on the occupational exposure to nanoparticles is insufficient. The present study performed an exposure monitoring in workplace environments where synthetic powders are prepared using fumed nanosilica. Furthermore, after it was observed during exposure monitoring that nanoparticles were emitted through leakage in a vacuum cleaner (even with a HEPA-filter installed in it), the properties of the leaked nanoparticles were also investigated. Workers were exposed to high-concentration nanosilica emitted into the air while pouring it into a container or transferring the container. The use of a vacuum cleaner with a leak (caused by an inadequate sealing) was found to be the origin of nanosilica dispersion in the indoor air. While the particle size of the nanosilica that emitted into the air (during the handling of nanosilica by a worker) was mostly over 100 nm or several microns (µm) due to the coagulation of particles, the size of nanosilica that leaked out of vacuum cleaner was almost similar to the primary size (mode diameter 11.5 nm). Analysis of area samples resulted in 20% (60% in terms of peak concentration) less than the analysis of the personals sample.

  2. Layer-by-layer assembled multilayers and polymeric nanoparticles for drug delivery in tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Mehrotra, Sumit

    Tissues and organs in vivo are structured in three dimensional (3-D) ordered assemblies to maintain their metabolic functions. In the case of an injury, certain tissues lack the regenerative abilities without an external supportive environment. In order to regenerate the natural in vivo environment post-injury, there is a need to design three-dimensional (3-D) tissue engineered constructs of appropriate dimensions along with strategies that can deliver growth factors or drugs at a controlled rate from such constructs. This thesis focuses on the applications of hydrogen bonded (H-bonded) nanoscale layer-by-layer (LbL) assembled multilayers for time controlled drug delivery, fabrication of polymeric nanoparticles as drug delivery carriers, and engineering 3-D cellular constructs. Axonal regeneration in the central nervous system after spinal cord injury is often disorganized and random. To support linear axonal growth into spinal cord lesion sites, certain growth factors, such as brain-derived neurotrophic factor (BDNF), needs to be delivered at a controlled rate from an array of uniaxial channels patterned in a scaffold. In this study, we demonstrate for the first time that H-bonded LbL assembled degradable thin films prepared over agarose hydrogel, whereby the protein was loaded separately from the agarose fabrication, provided sustained release of protein under physiological conditions for more than four weeks. Further, patterned agarose scaffolds implanted at the site of a spinal cord injury forms a reactive cell layer of leptomeningeal fibroblasts in and around the scaffold. This limits the ability of axons to reinnervate the spinal cord. To address this challenge, we demonstrate the time controlled release of an anti-mitotic agent from agarose hydrdgel to control the growth of the reactive cell layer of fibroblasts. Challenges in tissue engineering can also be addressed using gene therapy approaches. Certain growth factors in the body are known to inhibit

  3. An organizational cultural assessment of the Idaho National Engineering Laboratory

    SciTech Connect

    Crouch, D.A.; Haber, S.B.

    1991-07-01

    An Organizational Cultural Assessment (OCA) was performed at the Idaho National Engineering Laboratory (INEL) by administering an Organizational Culture Survey (OCS) that queried employees on the subjects of organizational culture, various aspects of communication, employee commitment, work group cohesion, coordination of work, environmental concerns, hazardous nature of work, safety, and overall job satisfaction. A description of each of the scales used to access these subjects is discussed. The primary purpose of administering the survey was to attempt to measure, in a quantitative and objective way the notion of organizational culture,'' that is, the values, attitudes, and beliefs of the individuals working within the organization. In particular, those aspects of the working environment which are believed to be important influences on the operations of a facility and on the safety issues relevant to the organization were assessed. In addition, by conducting a survey, a broad sampling of the individuals in the organization can be obtained. This is especially important when the survey is utilized in conjunction with an assessment or inspection team which typically has only a limited amount of resources to address many issues. The OCS provides a broad, but comprehensive picture of the organization by querying a much larger number of individuals than could be reached through the assessment team alone. Finally, the OCS provides a descriptive profile of the organization at one point in time. This profile can then be used as a baseline point against which comparisons of other points in time can be made. Such comparisons may prove valuable and would help to assess changes in the organizational culture. Comparisons of the profiles can also be made across similar facilities. 9 refs., 194 figs., 6 tabs.

  4. Organizational Cultural Assessment of the Idaho National Engineering Laboratory

    SciTech Connect

    Not Available

    1991-06-01

    An Organizational Cultural Assessment (OCA) was performed at the Idaho National Engineering Laboratory (INEL) by administering an Organizational Culture Survey (OCS) that queried employees on the subjects of organizational culture, various aspects of communications, employee commitment, work group cohesion, coordination of work, environmental concerns, hazardous nature of work, safety and overall job satisfaction. Many of these subjects are assessed in the OCS through highly developed and validated scales that have been administered in many different types of organizations. The purpose of the OCS is to measure in a quantitative and objective way the notion of culture;'' that is, the values, attitudes, and beliefs of the individuals working within the organization. In addition, through the OCS, a broad sample of individuals can be reached that would probably not be interviewed or observed during the course of a typical assessment. The OCS also provides a descriptive profile of the organization at one point in time that can then be compared to a profile taken at a different point in time to assess changes in the culture of the organization. The OCS administration at the INEL was the sixth to occur at a Department of Energy (DOE) facility. The INEL Organization is somewhat different from other DOE facilities are which the OCS was administered, due to the presence of six different major operating contractors. The seven organizations assessed at the INEL are: (1) Argonne National Laboratory -- West; (2) DOE Fire Department/Radiological and Environmental Sciences Laboratory; (3) EG G Idaho Incorporated; (4) MK Ferguson; (5) Protection Technology Incorporated; (6) Rockwell; and (7) Westinghouse Idaho Nuclear Company Incorporated. All data from the OCS is presented in group summaries by organization, Supervisory Level, Staff Classification, and department within organization. Statistically significant differences between groups are identified and discussed.

  5. Assessing potential peptide targeting ligands by quantification of cellular adhesion of model nanoparticles under flow conditions.

    PubMed

    Broda, Ellen; Mickler, Frauke Martina; Lächelt, Ulrich; Morys, Stephan; Wagner, Ernst; Bräuchle, Christoph

    2015-09-10

    Sophisticated drug delivery systems are coated with targeting ligands to improve the specific adhesion to surface receptors on diseased cells. In our study, we developed a method with which we assessed the potential of peptide ligands to specifically bind to receptor overexpressing target cells. Therefore, a microfluidic setup was used where the cellular adhesion of nanoparticles with ligand and of control nanoparticles was observed in parallel under the same experimental conditions. The effect of the ligand on cellular binding was quantified by counting the number of adhered nanoparticles with ligand and differently labeled control nanoparticles on single cells after incubation under flow conditions. To provide easy-to-synthesize, stable and reproducible nanoparticles which mimic the surface characteristics of drug delivery systems and meet the requirements for quantitative analysis, latex beads based on amine-modified polystyrene were used as model nanoparticles. Two short peptides were tested to serve as targeting ligand on the beads by increasing the specific binding to HuH7 cells. The c-Met binding peptide cMBP2 was used for hepatocyte growth factor receptor (c-Met) targeting and the peptide B6 for transferrin receptor (TfR) targeting. The impact of the targeting peptide on binding was investigated by comparing the beads with ligand to different internal control beads: 1) without ligand and tailored surface charge (electrostatic control) and 2) with scrambled peptide and similar surface charge, but a different amino acid sequence (specificity control). Our results demonstrate that the method is very useful to select suitable targeting ligands for specific nanoparticle binding to receptor overexpressing tumor cells. We show that the cMBP2 ligand specifically enhances nanoparticle adhesion to target cells, whereas the B6 peptide mediates binding to tumor cells mainly by nonspecific interactions. All together, we suggest that cMBP2 is a suitable choice for

  6. Re-engineering operating theatres: the perspective assessed.

    PubMed

    Buchanan, D; Wilson, B

    1996-01-01

    Refers to the widely experienced and appreciated difficulties in scheduling hospital operating theatres to make effective use of resources, and to avoid delays and overruns that can adversely affect patient care and staff morale. Reports the findings and recommendations of a project based in the Surgical Directorate of Leicester General Hospital NHS Trust which sought to address these problems from a business process re-engineering perspective. Covering the whole patient trail, from referral to discharge describes the project's progress through four phases concerning process mapping, the collection of staff opinions and ideas through a combination of interviews and surveys, collection of data on patient flows and procedure times, and a final "handover" phase in which broad recommendations were passed back to the Surgical Directorate for implementation with staff involvement. Details the recommendations which include a shift to cross-functional teamworking in a number of areas, along with the development of a revised theatres policy and a strengthened theatres co-ordination function. In view of recent substantial and harsh criticisms of the re-engineering perspective, seeks to offer a balanced assessment of the perspective applied to a health care setting, exploring both the problems and benefits.

  7. Explicitness of Criteria in Peer Assessment Processes for First-Year Engineering Students

    ERIC Educational Resources Information Center

    van Hattum-Janssen, Natascha; Lourenco, Julia Maria

    2006-01-01

    This article will outline the motives for the implementation of peer assessment as put into action at the first year of the Civil Engineering course of the University of Minho. The implementation of new assessment methods was a consequence of the successful implementation of peer assessment at other engineering courses. During the semester, three…

  8. Toxicity assessment of Titanium Dioxide and Cerium Oxide nanoparticles in Arabidopsis thaliana L.

    EPA Science Inventory

    The production and applications of nanoparticles (NP) in diverse fields has steadily increased in recent decades; however, knowledge about risks of NP to human health and ecosystems is still scarce. In this study, we assessed potential toxicity of two commercially used engineere...

  9. Stability studies of commercial ZnO engineered nanoparticles in domestic wastewater

    NASA Astrophysics Data System (ADS)

    Chaúque, E. F. C.; Zvimba, J. N.; Ngila, J. C.; Musee, N.

    Most wastewater treatment plants (WWTPs) employ activated sludge processes to treat wastewater. The bacteria found in these systems degrade organic matter but are very sensitive to toxic compounds such as heavy metals, among others. The impact of emerging contaminants, such as engineered nanoparticles (ENPs) on the treatment efficiency of WWTPs is yet to be fully elucidated. The effects of physicochemical parameters; the pH and ionic strength on ZnO ENPs in domestic wastewater were investigated to establish their fate and behavior in wastewater treatment systems, as well as potential release into the environment if they pass untreated. Our findings showed a decrease in zinc concentration in the filtrate as pH and ionic strength increased which indicated its possible removal through the abiotic, biosorption, and biosolid settling mechanisms. This phenomenon was further confirmed by transmission electron microscopy (TEM) images which showed agglomerates of ZnO ENPs in wastewater compared with de-ionized water. The dynamic light scattering (DLS) analysis of ZnO ENPs suspension in the wastewater showed their stability over a period of 2 h, with energy dispersive X-ray (EDS) analysis showing the presence of zinc on the sludge surface, while X-ray diffraction (XRD) analysis confirmed the presence of ZnO ENPs in the sludge over typical wastewater pH ranges. The results of this study will inform the integrated water management on the impact of nanotechnology based industries and the best approach in handling wastewater treatment products.

  10. Development of Multifunctional Magnetic Nanoparticles for Genetic Engineering and Tracking of Neural Stem Cells.

    PubMed

    Adams, Christopher; Israel, Liron Limor; Ostrovsky, Stella; Taylor, Arthur; Poptani, Harish; Lellouche, Jean-Paul; Chari, Divya

    2016-04-06

    Genetic modification of cell transplant populations and cell tracking ability are key underpinnings for effective cell therapies. Current strategies to achieve these goals utilize methods which are unsuitable for clinical translation because of related safety issues, and multiple protocol steps adding to cost and complexity. Multifunctional magnetic nanoparticles (MNPs) offering dual mode gene delivery and imaging contrast capacity offer a valuable tool in this context. Despite their key benefits, there is a critical lack of neurocompatible and multifunctional particles described for use with transplant populations for neurological applications. Here, a systematic screen of MNPs (using a core shown to cause contrast in magnetic resonance imaging (MRI)) bearing various surface chemistries (polyethylenimine (PEI) and oxidized PEI and hybrids of oxidized PEI/alginic acid, PEI/chitosan and PEI/polyamidoamine) is performed to test their ability to genetically engineer neural stem cells (NSCs; a cell population of high clinical relevance for central nervous system disorders). It is demonstrated that gene delivery to NSCs can be safely achieved using two of the developed formulations (PEI and oxPEI/alginic acid) when used in conjunction with oscillating magnetofection technology. After transfection, intracellular particles can be detected by histological procedures with labeled cells displaying contrast in MRI (for real time cell tracking).

  11. Impact of Engineered Zinc Oxide Nanoparticles on the Individual Performance of Mytilus galloprovincialis

    PubMed Central

    Hanna, Shannon K.; Miller, Robert J.; Muller, Erik B.; Nisbet, Roger M.; Lenihan, Hunter S.

    2013-01-01

    The increased use of engineered nanoparticles (ENPs) in consumer products raises the concern of environmental release and subsequent impacts in natural communities. We tested for physiological and demographic impacts of ZnO, a prevalent metal oxide ENP, on the mussel Mytilus galloprovincialis. We exposed mussels of two size classes, <4.5 and ≥4.5 cm shell length, to 0.1–2 mg l−1 ZnO ENPs in seawater for 12 wk, and measured the effect on mussel respiration, accumulation of Zn, growth, and survival. After 12 wk of exposure to ZnO ENPs, respiration rates of mussels increased with ZnO concentration. Mussels had up to three fold more Zn in tissues than control groups after 12 wk of exposure, but patterns of Zn accumulation varied with mussel size and Zn concentrations. Small mussels accumulated Zn 10 times faster than large mussels at 0.5 mg l−1, while large mussels accumulated Zn four times faster than small mussels at 2 mg l−1. Mussels exposed to 2 mg l−1 ZnO grew 40% less than mussels in our control group for both size classes. Survival significantly decreased only in groups exposed to the highest ZnO concentration (2 mg l−1) and was lower for small mussels than large. Our results indicate that ZnO ENPs are toxic to mussels but at levels unlikely to be reached in natural marine waters. PMID:23613941

  12. Impact of engineered zinc oxide nanoparticles on the individual performance of Mytilus galloprovincialis.

    PubMed

    Hanna, Shannon K; Miller, Robert J; Muller, Erik B; Nisbet, Roger M; Lenihan, Hunter S

    2013-01-01

    The increased use of engineered nanoparticles (ENPs) in consumer products raises the concern of environmental release and subsequent impacts in natural communities. We tested for physiological and demographic impacts of ZnO, a prevalent metal oxide ENP, on the mussel Mytilus galloprovincialis. We exposed mussels of two size classes, <4.5 and ≥ 4.5 cm shell length, to 0.1-2 mg l(-1) ZnO ENPs in seawater for 12 wk, and measured the effect on mussel respiration, accumulation of Zn, growth, and survival. After 12 wk of exposure to ZnO ENPs, respiration rates of mussels increased with ZnO concentration. Mussels had up to three fold more Zn in tissues than control groups after 12 wk of exposure, but patterns of Zn accumulation varied with mussel size and Zn concentrations. Small mussels accumulated Zn 10 times faster than large mussels at 0.5 mg l(-1), while large mussels accumulated Zn four times faster than small mussels at 2 mg l(-1). Mussels exposed to 2 mg l(-1) ZnO grew 40% less than mussels in our control group for both size classes. Survival significantly decreased only in groups exposed to the highest ZnO concentration (2 mg l(-1)) and was lower for small mussels than large. Our results indicate that ZnO ENPs are toxic to mussels but at levels unlikely to be reached in natural marine waters.

  13. Evaluation of engineered nanoparticle toxic effect on wastewater microorganisms: current status and challenges.

    PubMed

    Eduok, S; Martin, B; Villa, R; Nocker, A; Jefferson, B; Coulon, F

    2013-09-01

    The use of engineered nanoparticles (ENPs) in a wide range of products is associated with an increased concern for environmental safety due to their potential toxicological and adverse effects. ENPs exert antimicrobial properties through different mechanisms such as the formation of reactive oxygen species, disruption of physiological and metabolic processes. Although there are little empirical evidences on environmental fate and transport of ENPs, biosolids in wastewater most likely would be a sink for ENPs. However, there are still many uncertainties in relation to ENPs impact on the biological processes during wastewater treatment. This review provides an overview of the available data on the plausible effects of ENPs on AS and AD processes, two key biologically relevant environments for understanding ENPs-microbial interactions. It indicates that the impact of ENPs is not fully understood and few evidences suggest that ENPs could augment microbial-mediated processes such as AS and AD. Further to this, wastewater components can enhance or attenuate ENPs effects. Meanwhile it is still difficult to determine effective doses and establish toxicological guidelines, which is in part due to variable wastewater composition and inadequacy of current analytical procedures. Challenges associated with toxicity evaluation and data interpretation highlight areas in need for further research studies.

  14. [Behaviors of engineered nanoparticles in aquatic environments and impacts on marine phytoplankton].

    PubMed

    Li, Man-lu; Jiang, Yue-lu

    2015-01-01

    Engineered nanoparticles (ENPs) have shown invaluable societal benefits and applications in drug targeting, biological imaging and industrial products. ENPs enter the water body through various paths during the processes of production, usage and emission, therefore the behavior and the biosafety of ENPs in water bodies have attracted increasing attention. As the primary producer of ecosystems, phytoplankton provide nutrients, energy and oxygen for both themselves and organisms at higher trophic levels in the aquatic ecosystems. These primary producers may be exposed to the biological and unpredictable effects of this emergent pollutant to the aquatic ecosystems. Numerous studies have proved the toxic effects of ENPs on phytoplankton, but the mechanisms of entry into the aquatic organisms as well as the stability, fate and biotransformation in phytoplankton still remain unclear. Here, we present a review of the pathways of ENPs entering the water, the subsequent behavior and biological effects of ENPs on phytoplankton with an emphasis on latest findings and current knowledge. Future research and endeavors shall focus further on the understanding of mechanisms, fate and transport of ENPs in the aquatic ecosystems.

  15. Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering.

    PubMed

    Baei, Payam; Jalili-Firoozinezhad, Sasan; Rajabi-Zeleti, Sareh; Tafazzoli-Shadpour, Mohammad; Baharvand, Hossein; Aghdami, Nasser

    2016-06-01

    Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14 days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues.

  16. A Chemically Polymerized Electrically Conducting Composite of Polypyrrole Nanoparticles and Polyurethane for Tissue Engineering

    PubMed Central

    Broda, Christopher R.; Lee, Jae Y.; Sirivisoot, Sirinrath; Schmidt, Christine E.; Harrison, Benjamin S.

    2011-01-01

    A variety of cell types respond to electrical stimuli, accordingly many conducting polymers (CPs) have been used as tissue engineering (TE) scaffolds, one such CP is polypyrrole (PPy). PPy is a well studied biomaterial with potential TE applications due to its electrical conductivity and many other beneficial properties. Combining its characteristics with an elastomeric material, such as polyurethane (PU), may yield a hybrid scaffold with electrical activity and significant mechanical resilience. Pyrrole was in situ polymerized within a PU emulsion mixture in weight ratios of 1:100, 1:20, 1:10 and 1:5, respectively. Morphology, electrical conductivity, mechanical properties and cytocompatibility with C2C12 myoblast cells were characterized. The polymerization resulted in a composite with a principle base of PU interspersed with an electrically percolating network of PPy nanoparticles. As the mass ratio of PPy to PU increased so did electrical conductivity of the composites. In addition, as the mass ratio of PPy to PU increased, stiffness of the composite increased while maximum elongation length decreased. Ultimate tensile strength was reduced by approximately 47% across all samples with the addition of PPy to the PU base. Cytocompatibility assay data indicated no significant cytotoxic effect from the composites. Static cellular seeding of C2C12 cells and subsequent differentiation showed myotube formation on the composite materials. PMID:21681943

  17. Safety and efficacy of composite collagen-silver nanoparticle hydrogels as tissue engineering scaffolds.

    PubMed

    Alarcon, Emilio I; Udekwu, Klas I; Noel, Christopher W; Gagnon, Luke B-P; Taylor, Patrick K; Vulesevic, Branka; Simpson, Madeline J; Gkotzis, Spyridon; Islam, M Mirazul; Lee, Chyan-Jang; Richter-Dahlfors, Agneta; Mah, Thien-Fah; Suuronen, Erik J; Scaiano, Juan C; Griffith, May

    2015-11-28

    The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and other inflammation markers (CCL24, sTNFR-2, and TIMP1). Finally, an analysis of silver contents in implanted mice showed that silver accumulation primarily occurred within the tissue surrounding the implant.

  18. How important is drinking water exposure for the risks of engineered nanoparticles to consumers?

    PubMed

    Tiede, Karen; Hanssen, Steffen Foss; Westerhoff, Paul; Fern, Gordon J; Hankin, Steven M; Aitken, Robert J; Chaudhry, Qasim; Boxall, Alistair B A

    2016-01-01

    This study explored the potential for engineered nanoparticles (ENPs) to contaminate the UK drinking water supplies and established the significance of the drinking water exposure route compared to other routes of human exposure. A review of the occurrence and quantities of ENPs in different product types on the UK market as well as release scenarios, their possible fate and behaviour in raw water and during drinking water treatment was performed. Based on the available data, all the ENPs which are likely to reach water sources were identified and categorized. Worst case concentrations of ENPs in raw water and treated drinking water, using a simple exposure model, were estimated and then qualitatively compared to available estimates for human exposure through other routes. A range of metal, metal oxide and organic-based ENPs were identified that have the potential to contaminate drinking waters. Worst case predicted concentrations in drinking waters were in the low- to sub-µg/l range and more realistic estimates were tens of ng/l or less. For the majority of product types, human exposure via drinking water was predicted to be less important than exposure via other routes. The exceptions were some clothing materials, paints and coatings and cleaning products containing Ag, Al, TiO2, Fe2O3 ENPs and carbon-based materials.

  19. An approach for environmental risk assessment of engineered nanomaterials using Analytical Hierarchy Process (AHP) and fuzzy inference rules.

    PubMed

    Topuz, Emel; van Gestel, Cornelis A M

    2016-01-01

    The usage of Engineered Nanoparticles (ENPs) in consumer products is relatively new and there is a need to conduct environmental risk assessment (ERA) to evaluate their impacts on the environment. However, alternative approaches are required for ERA of ENPs because of the huge gap in data and knowledge compared to conventional pollutants and their unique properties that make it difficult to apply existing approaches. This study aims to propose an ERA approach for ENPs by integrating Analytical Hierarchy Process (AHP) and fuzzy inference models which provide a systematic evaluation of risk factors and reducing uncertainty about the data and information, respectively. Risk is assumed to be the combination of occurrence likelihood, exposure potential and toxic effects in the environment. A hierarchy was established to evaluate the sub factors of these components. Evaluation was made with fuzzy numbers to reduce uncertainty and incorporate the expert judgements. Overall score of each component was combined with fuzzy inference rules by using expert judgements. Proposed approach reports the risk class and its membership degree such as Minor (0.7). Therefore, results are precise and helpful to determine the risk management strategies. Moreover, priority weights calculated by comparing the risk factors based on their importance for the risk enable users to understand which factor is effective on the risk. Proposed approach was applied for Ag (two nanoparticles with different coating) and TiO2 nanoparticles for different case studies. Results verified the proposed benefits of the approach.

  20. Quantitative photothermal heating and cooling measurements of engineered nanoparticles in an optical trap

    NASA Astrophysics Data System (ADS)

    Roder, Paden Bernard

    hot Brownian motion theory, we attempt to measure realistic temperatures at the surface of an optically-trapped particle while properly accounting for inhomogeneous temperature fields generated by the optical trap. In Chapter 5, this technique is then applied to measure the temperature of engineered gold- and silicon-implanted silicon nanowires to rigorously study the effect ion implantation has on silicon nanowire photothermal efficiencies. Silicon nanowire photothermal efficiencies are shown to drastically increase by implanting with gold ions and cause superheating of water of over 200 C at the trap site, suggesting potential application as agents for photothermal cancer therapies. Chapter 6 describes the hydrothermal synthesis and optical trapping of engineered YLF nanoparticles doped with Yb(III) ions. Laser tweezer experiments using the developed temperature extraction techniques and hot Brownian motion analysis show the first observation of particles undergoing recently hypothesized cold Brownian motion and local laser refrigeration in a condensed phase via anti-Stokes photoluminescence. Furthermore, YLF nanoparticles codoped with Er(III) and Yb(III) ions are also developed and their intense visible upconversion of the NIR trapping laser is used to monitor its internal lattice temperature using ratiometric thermography. The results suggest the potential of these materials to investigate kinetics and temperature sensitivity of basic cellular processes, or to act as simultaneous theranostic-hypothermia agents to identify and treat cancerous tissues. Finally, Chapter 7 presents a summary of the salient conclusions of the reported studies. The chapter concludes with a short discussion of my personal experience with being a member of a new research group and setting up the Pauzauskie laboratory.

  1. Surface engineering of macrophages with nanoparticles to generate a cell-nanoparticle hybrid vehicle for hypoxia-targeted drug delivery.

    PubMed

    Holden, Christopher A; Yuan, Quan; Yeudall, W Andrew; Lebman, Deborah A; Yang, Hu

    2010-02-02

    Tumors frequently contain hypoxic regions that result from a shortage of oxygen due to poorly organized tumor vasculature. Cancer cells in these areas are resistant to radiation- and chemotherapy, limiting the treatment efficacy. Macrophages have inherent hypoxia-targeting ability and hold great advantages for targeted delivery of anticancer therapeutics to cancer cells in hypoxic areas. However, most anticancer drugs cannot be directly loaded into macrophages because of their toxicity. In this work, we designed a novel drug delivery vehicle by hybridizing macrophages with nanoparticles through cell surface modification. Nanoparticles immobilized on the cell surface provide numerous new sites for anticancer drug loading, hence potentially minimizing the toxic effect of anticancer drugs on the viability and hypoxia-targeting ability of the macrophage vehicles. In particular, quantum dots and 5-(aminoacetamido) fluorescein-labeled polyamidoamine dendrimer G4.5, both of which were coated with amine-derivatized polyethylene glycol, were immobilized to the sodium periodate-treated surface of RAW264.7 macrophages through a transient Schiff base linkage. Further, a reducing agent, sodium cyanoborohydride, was applied to reduce Schiff bases to stable secondary amine linkages. The distribution of nanoparticles on the cell surface was confirmed by fluorescence imaging, and it was found to be dependent on the stability of the linkages coupling nanoparticles to the cell surface.

  2. Silver nanoparticles in complex biological media: assessment of colloidal stability and protein corona formation

    NASA Astrophysics Data System (ADS)

    Argentiere, Simona; Cella, Claudia; Cesaria, Maura; Milani, Paolo; Lenardi, Cristina

    2016-08-01

    Engineered silver nanoparticles (AgNPs) are among the most used nanomaterials in consumer products, therefore concerns are raised about their potential for adverse effects in humans and environment. Although an increasing number of studies in vitro and in vivo are being reported on the toxicity of AgNPs, most of them suffer from incomplete characterization of AgNPs in the tested biological media. As a consequence, the comparison of toxicological data is troublesome and the toxicity evaluation still remains an open critical issue. The development of a reliable protocol to evaluate interactions of AgNPs with surrounding proteins as well as to assess their colloidal stability is therefore required. In this regard, it is of importance not only to use multiple, easy-to-access and simple techniques but also to understand limitations of each characterization methods. In this work, the morphological and structural behaviour of AgNPs has been studied in two relevant biological media, namely 10 % FBS and MP. Three different techniques (Dynamic Light Scattering, Transmission Electron Microscopy, UV-Vis spectroscopy) were tested for their suitability in detecting AgNPs of three different sizes (10, 40 and 100 nm) coated with either citrate or polyvinylpyrrolidone. Results showed that UV-Vis spectroscopy is the most versatile and informative technique to gain information about interaction between AgNPs and surrounding proteins and to determine their colloidal stability in the tested biological media. These findings are expected to provide useful insights in characterizing AgNPs before performing any further in vitro/in vivo experiment.

  3. Engineering epithelial-stromal interactions in vitro for toxicology assessment.

    PubMed

    Belair, David G; Abbott, Barbara D

    2017-03-08

    Crosstalk between epithelial and stromal cells drives the morphogenesis of ectodermal organs during development and promotes normal mature adult epithelial tissue homeostasis. Epithelial-stromal interactions (ESIs) have historically been examined using mammalian models and ex vivo tissue recombination. Although these approaches have elucidated signaling mechanisms underlying embryonic morphogenesis processes and adult mammalian epithelial tissue function, they are limited by the availability of tissue, low throughput, and human developmental or physiological relevance. In this review, we describe how bioengineered ESIs, using either human stem cells or co-cultures of human primary epithelial and stromal cells, have enabled the development of human in vitro epithelial tissue models that recapitulate the architecture, phenotype, and function of adult human epithelial tissues. We discuss how the strategies used to engineer mature epithelial tissue models in vitro could be extrapolated to instruct the design of organotypic culture models that can recapitulate the structure of embryonic ectodermal tissues and enable the in vitro assessment of events critical to organ/tissue morphogenesis. Given the importance of ESIs towards normal epithelial tissue development and function, such models present a unique opportunity for toxicological screening assays to incorporate ESIs to assess the impact of chemicals on mature and developing epidermal tissues.

  4. Reactor technology assessment and selection utilizing systems engineering approach

    SciTech Connect

    Zolkaffly, Muhammed Zulfakar; Han, Ki-In

    2014-02-12

    The first Nuclear power plant (NPP) deployment in a country is a complex process that needs to consider technical, economic and financial aspects along with other aspects like public acceptance. Increased interest in the deployment of new NPPs, both among newcomer countries and those with expanding programs, necessitates the selection of reactor technology among commercially available technologies. This paper reviews the Systems Decision Process (SDP) of Systems Engineering and applies it in selecting the most appropriate reactor technology for the deployment in Malaysia. The integrated qualitative and quantitative analyses employed in the SDP are explored to perform reactor technology assessment and to select the most feasible technology whose design has also to comply with the IAEA standard requirements and other relevant requirements that have been established in this study. A quick Malaysian case study result suggests that the country reside with PWR (pressurized water reactor) technologies with more detailed study to be performed in the future for the selection of the most appropriate reactor technology for Malaysia. The demonstrated technology assessment also proposes an alternative method to systematically and quantitatively select the most appropriate reactor technology.

  5. Reactor technology assessment and selection utilizing systems engineering approach

    NASA Astrophysics Data System (ADS)

    Zolkaffly, Muhammed Zulfakar; Han, Ki-In

    2014-02-01

    The first Nuclear power plant (NPP) deployment in a country is a complex process that needs to consider technical, economic and financial aspects along with other aspects like public acceptance. Increased interest in the deployment of new NPPs, both among newcomer countries and those with expanding programs, necessitates the selection of reactor technology among commercially available technologies. This paper reviews the Systems Decision Process (SDP) of Systems Engineering and applies it in selecting the most appropriate reactor technology for the deployment in Malaysia. The integrated qualitative and quantitative analyses employed in the SDP are explored to perform reactor technology assessment and to select the most feasible technology whose design has also to comply with the IAEA standard requirements and other relevant requirements that have been established in this study. A quick Malaysian case study result suggests that the country reside with PWR (pressurized water reactor) technologies with more detailed study to be performed in the future for the selection of the most appropriate reactor technology for Malaysia. The demonstrated technology assessment also proposes an alternative method to systematically and quantitatively select the most appropriate reactor technology.

  6. Need Assessment of Computer Science and Engineering Graduates

    NASA Astrophysics Data System (ADS)

    Surakka, Sami; Malmi, Lauri

    2005-06-01

    This case study considered the syllabus of the first and second year studies in computer science. The aim of the study was to reveal which topics covered in the syllabi were really needed during the following years of study or in working life. The program that was assessed in the study was a Masters program in computer science and engineering at a university of technology in Finland. The necessity of different subjects for the advanced studies (years 3? ?5) and for working life was assessed using four content analyses: (a) the course catalog of the institution where this study was carried out, (b) employment reports that were attached to the applications for internship credits, (c) masters theses, and (d) job advertisements in a newspaper. The results of the study imply that the necessity of physics for the advanced study and work was very low compared to the extent to which it was studied. On the other hand, the necessity for mathematics was moderate, and it had remained quite steady during the period 1989? ?2002. The most necessary computer science topic was programming. Also telecommunications and networking was needed often, whereas theoretical computer science was needed quite rarely.

  7. Engineering Risk Assessment of Space Thruster Challenge Problem

    NASA Technical Reports Server (NTRS)

    Mathias, Donovan L.; Mattenberger, Christopher J.; Go, Susie

    2014-01-01

    The Engineering Risk Assessment (ERA) team at NASA Ames Research Center utilizes dynamic models with linked physics-of-failure analyses to produce quantitative risk assessments of space exploration missions. This paper applies the ERA approach to the baseline and extended versions of the PSAM Space Thruster Challenge Problem, which investigates mission risk for a deep space ion propulsion system with time-varying thruster requirements and operations schedules. The dynamic mission is modeled using a combination of discrete and continuous-time reliability elements within the commercially available GoldSim software. Loss-of-mission (LOM) probability results are generated via Monte Carlo sampling performed by the integrated model. Model convergence studies are presented to illustrate the sensitivity of integrated LOM results to the number of Monte Carlo trials. A deterministic risk model was also built for the three baseline and extended missions using the Ames Reliability Tool (ART), and results are compared to the simulation results to evaluate the relative importance of mission dynamics. The ART model did a reasonable job of matching the simulation models for the baseline case, while a hybrid approach using offline dynamic models was required for the extended missions. This study highlighted that state-of-the-art techniques can adequately adapt to a range of dynamic problems.

  8. Nanoparticles rapidly assess specific IgE in plasma

    NASA Astrophysics Data System (ADS)

    Ashraf, Sarmadia; Qadri, Shahnaz; al-Ramadi, Basel; Haik, Yousef

    2012-08-01

    Allergy is the sixth leading cause of chronic disease in the world. This study demonstrates the feasibility of detecting allergy indicators in human plasma, noninvasively, at the point of care and with a comparable efficiency and reduced turnaround time compared with the gold standard. Peanut allergy was utilized as a model due to its widespread occurrence among the US population and fatality if not treated. The detection procedure utilized magnetic nanoparticles that were coated with an allergen layer (peanut protein extract). Peanut immunoglobulin E (IgE) was detected in concentrations close to the minimum detection range of CAP assay. The results were obtained in minutes compared with the CAP assay which requires more than 3 h.

  9. In Vitro Toxicological Assessment of Magnesium Oxide Nanoparticle Exposure in Several Mammalian Cell Types.

    PubMed

    Mahmoud, Abudayyak; Ezgi, Öztaş; Merve, Arici; Özhan, Gül

    2016-07-01

    Worldwide researchers have rising concerns about magnesium-based materials, especially magnesium oxide (MgO) nanaoparticles, due to increasing usage as promising structural materials in various fields including cancer treatment. However, there is a serious lack of information about their toxicity at the cellular and molecular levels. In this study, the toxic potentials of MgO nanoparticles were investigated on liver (HepG2), kidney (NRK-52E), intestine (Caco-2), and lung (A549) cell lines. For the toxicological assessment, the following assays were used: the particle characterization by transmission electron microscopy, the determination of cellular uptake by inductively coupled plasma-mass spectrometry, MTT and neutral red uptake assays for cytotoxicity, comet assay for genotoxicity, and the determination of malondialdehyde (MDA), 8-hydroxydeoxyguanosine, protein carbonyl, and glutathione levels by enzyme-linked immune sorbent assays for the potential of oxidative damage and annexin V-fluorescein isothiocyanate (FITC) apoptosis detection assay with propidium iodide (PI) for apoptosis. Magnesium oxide nanoparticles were taken up by the cells depending on their concentration and agglomeration/aggregation potentials. Magnesium oxide nanoparticles induced DNA (≤14.27 fold) and oxidative damage. At a concentration of ≥323.39 µg/mL, MgO nanoparticles caused 50% inhibition in cell viability by 2 different cytotoxicity assays. The cell sensitivity to cytotoxic and genotoxic damage induced by MgO nanoparticles was ranked as HepG2 < A549 < Caco-2 < NRK-52E. Although it was observed that MgO nanoparticles induced apoptotic effects on the cells, apoptosis was not the main cell death. DNA damage, cell death, and oxidative damage effects of MgO nanoparticles should raise concern about the safety associated with their applications in consumer products.

  10. Science and the lay perspective: lay people's involvement in assessing tissue engineering.

    PubMed

    Zoeller, Katharina

    2014-10-01

    Tissue engineering (TE) is a scientific field that will have an influence on our daily lives. It has the potential to revolutionize medical treatments, but it has also an impact on our human image and is associated with potential risks and ethical aspects. Among the publicly controversial issues are embryonic and induced pluripotent stem cells, cloning, uncertainties regarding risks and informed consent issues. To maintain public confidence in the science of TE, a good solution is public dialogues with patients and other interested lay people that gives the public the chance to independently evaluate TE issues and build their own opinion based on information from different perspectives. The article describes public participation projects in TE on stem cell research and gene therapy and presents the case study of the EU-Gene Activated Matrices for Bone and Cartilage Regeneration on Arthritis (GAMBA) panels, a dialogue with patient and citizen panels in three European countries. In the GAMBA panels, lay participants assessed the basic research project aimed at finding ways of healing osteoarthritis through a matrix composed of adult stem cells, gene vectors, nanoparticles, and biomaterials. The results of the dialogues in different countries, such as Denmark, Japan, Ireland, Switzerland, and Germany, are compared and the evaluation criteria for high quality dialogues are presented, including multiperspectivity, openness of results, a clear mandate, impartial facilitation of the panels, and transparency.

  11. Synthesis of Ca P nanoparticles and fabrication of Ca P/PHBV nanocomposite microspheres for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Duan, B.; Wang, M.; Zhou, W. Y.; Cheung, W. L.

    2008-11-01

    As the first step in producing totally bioresorbable osteoconductive composite scaffolds for bone tissue engineering using the selective laser sintering technology, bioresorbable nanoparticles of calcium phosphate (Ca-P) similar in composition to β-tricalcium phosphate were synthesized and Ca-P nanoparticle filled poly(hydroxybutyrate- co-hydroxyvalerate) (PHBV) microspheres were fabricated. The pH of the chemical reaction for Ca-P particle synthesis was found to have significant effects on the morphology and chemical composition of Ca-P precipitated. Ca-P particles produced at the pH of 10.0-11.0 were amorphous, had a Ca:P molar ratio of about 1.5, were spherical in shape and had sizes in the range of 10-30 nm. The Ca-P particles were used to form Ca-P nanocomposite microspheres through a solid-in-oil-in-water (S/O/W) emulsion solvent evaporation process. Ca-P nanoparticles were mostly encapsulated inside the microspheres and some Ca-P nanoparticles were superficially embedded on the microspheres. The Ca-P/PHBV microspheres had an average diameter of about 48 μm which is suitable for selective laser sintering for constructing osteoconductive composite scaffolds.

  12. Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials.

    PubMed

    Byeon, Jeong Hoon; Park, Jae Hong; Peters, Thomas M; Roberts, Jeffrey T

    2015-07-15

    The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled.

  13. Occupational Exposure to Airborne Nanomaterials: An Assessment of Worker Exposure to Aerosolized Metal Oxide Nanoparticles in Semiconductor Wastewater Treatment.

    PubMed

    Brenner, Sara A; Neu-Baker, Nicole M; Caglayan, Cihan; Zurbenko, Igor G

    2015-01-01

    This study characterized potential inhalation exposures of workers to nanometal oxides associated with industrial wastewater treatment processes in a semiconductor research and development facility. Exposure assessment methodology was designed to capture aerosolized engineered nanomaterials associated with the chemical mechanical planarization wafer polishing process that were accessible for worker contact via inhalation in the on-site wastewater treatment facility. The research team conducted air sampling using a combination of filter-based capture methods for particle identification and characterization and real-time direct-reading instruments for semi-quantitation of particle number concentration. Filter-based samples were analyzed using electron microscopy and energy-dispersive x-ray spectroscopy while real-time particle counting data underwent statistical analysis. Sampling conducted over 14 months included 5 discrete sampling series events for 7 job tasks in coordination with on-site employees. The number of filter-based samples captured for analysis by electron microscopy was: 5 from personal breathing zone, 4 from task areas, and 3 from the background. Direct-reading instruments collected data for 5 sample collection periods in the task area and the background, and 2 extended background collection periods. Engineered nanomaterials of interest (Si, Al, Ce) were identified by electron microscopy in filter-based samples from all areas of collection, existing as agglomerates (>500 nm) and nanoparticles (100 nm-500 nm). Particle counts showed an increase in number concentration during and after selected tasks above background. While additional data is needed to support further statistical analysis and determine trends, this initial investigation suggests that nanoparticles used or generated by chemical mechanical planarization become aerosolized and may be accessible for inhalation exposures by workers in wastewater treatment facilities. Additional research is

  14. Cerebrolysin, a mixture of neurotrophic factors induces marked neuroprotection in spinal cord injury following intoxication of engineered nanoparticles from metals.

    PubMed

    Menon, Preeti Kumaran; Muresanu, Dafin Fior; Sharma, Aruna; Mössler, Herbert; Sharma, Hari Shanker

    2012-02-01

    Spinal cord injury (SCI) is the world's most disastrous disease for which there is no effective treatment till today. Several studies suggest that nanoparticles could adversely influence the pathology of SCI and thereby alter the efficacy of many neuroprotective agents. Thus, there is an urgent need to find suitable therapeutic agents that could minimize cord pathology following trauma upon nanoparticle intoxication. Our laboratory has been engaged for the last 7 years in finding suitable therapeutic strategies that could equally reduce cord pathology in normal and in nanoparticle-treated animal models of SCI. We observed that engineered nanoparticles from metals e.g., aluminum (Al), silver (Ag) and copper (Cu) (50-60 nm) when administered in rats daily for 7 days (50 mg/kg, i.p.) resulted in exacerbation of cord pathology after trauma that correlated well with breakdown of the blood-spinal cord barrier (BSCB) to serum proteins. The entry of plasma proteins into the cord leads to edema formation and neuronal damage. Thus, future drugs should be designed in such a way to be effective even when the SCI is influenced by nanoparticles. Previous research suggests that a suitable combination of neurotrophic factors could induce marked neuroprotection in SCI in normal animals. Thus, we examined the effects of a new drug; cerebrolysin that is a mixture of different neurotrophic factors e.g., brain-derived neurotrophic factor (BDNF), glial cell line derived neurotrophic factor (GDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF) and other peptide fragments to treat normal or nanoparticle-treated rats after SCI. Our observations showed that cerebrolysin (2.5 ml/kg, i.v.) before SCI resulted in good neuroprotection in normal animals, whereas nanoparticle-treated rats required a higher dose of the drug (5.0 ml/kg, i.v.) to induce comparable neuroprotection in the cord after SCI. Cerebrolysin also reduced spinal cord water content, leakage of plasma proteins

  15. Ultra Efficient Engine Technology Systems Integration and Environmental Assessment

    NASA Technical Reports Server (NTRS)

    Daggett, David L.; Geiselhart, Karl A. (Technical Monitor)

    2002-01-01

    This study documents the design and analysis of four types of advanced technology commercial transport airplane configurations (small, medium large and very large) with an assumed technology readiness date of 2010. These airplane configurations were used as a platform to evaluate the design concept and installed performance of advanced technology engines being developed under the NASA Ultra Efficient Engine Technology (UEET) program. Upon installation of the UEET engines onto the UEET advanced technology airframes, the small and medium airplanes both achieved an additional 16% increase in fuel efficiency when using GE advanced turbofan engines. The large airplane achieved an 18% increase in fuel efficiency when using the P&W geared fan engine. The very large airplane (i.e. BWB), also using P&W geared fan engines, only achieved an additional 16% that was attributed to a non-optimized airplane/engine combination.

  16. Transport and Reactivity of Engineered Nanoparticles in Partially Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Dror, I.; Yecheskel, Y.; Berkowitz, B.

    2015-12-01

    Engineered nanoparticles (ENPs) are being produced in increasing amounts and have numerous applications in a variety of products and industrial processes. The same properties that make these substances so appealing may also cause them to act as persistent and toxic pollutants. The post-use release of ENPs to the environment is inevitable and soil appears to be one of the largest sinks of these potential contaminants. To date, despite the significant attention that ENP behavior in the environment has received, only a few studies have considered the fate and transport of ENPs in partially saturated systems. Here, we report measurements on the transport and fate of three commonly used ENPs - silver (Ag), gold (Au) and zinc oxide (ZnO) - in partially saturated porous media. The results show that ENP interactions with the solid matrix and solution components affect the fate of the ENPs and their transport. The negatively charged ENPs (AgNPs and AuNPs) are shown to be mobile in sand (which is also negatively charged) under various conditions, including water saturation levels and inlet concentration, with transport behavior resembling conservative tracer movement. Various aging scenarios were considered and the interaction of AgNPs with sulfides, chlorides, and calcium ions, all of which are known to interact and change AgNP properties, are shown to affect AgNP fate; however, in some cases, the changed particles remained suspended in solution and mobile. The positively charged ZnO showed very low mobility, but when humic acid was present in the inlet solution, interactions leading to enhanced mobility were observed. The presence of humic acid also changes ENP size and surface charge, transforming them to negatively charged larger aggregates that can be transported through the sand. Finally, remobilization of particles that were retained in the porous media was also demonstrated for ZnO ENPs, indicating possible release of entrapped ENPs upon changes in solution chemistry.

  17. Addressing the complexity of water chemistry in environmental fate modeling for engineered nanoparticles.

    PubMed

    Sani-Kast, Nicole; Scheringer, Martin; Slomberg, Danielle; Labille, Jérôme; Praetorius, Antonia; Ollivier, Patrick; Hungerbühler, Konrad

    2015-12-01

    Engineered nanoparticle (ENP) fate models developed to date - aimed at predicting ENP concentration in the aqueous environment - have limited applicability because they employ constant environmental conditions along the modeled system or a highly specific environmental representation; both approaches do not show the effects of spatial and/or temporal variability. To address this conceptual gap, we developed a novel modeling strategy that: 1) incorporates spatial variability in environmental conditions in an existing ENP fate model; and 2) analyzes the effect of a wide range of randomly sampled environmental conditions (representing variations in water chemistry). This approach was employed to investigate the transport of nano-TiO2 in the Lower Rhône River (France) under numerous sets of environmental conditions. The predicted spatial concentration profiles of nano-TiO2 were then grouped according to their similarity by using cluster analysis. The analysis resulted in a small number of clusters representing groups of spatial concentration profiles. All clusters show nano-TiO2 accumulation in the sediment layer, supporting results from previous studies. Analysis of the characteristic features of each cluster demonstrated a strong association between the water conditions in regions close to the ENP emission source and the cluster membership of the corresponding spatial concentration profiles. In particular, water compositions favoring heteroaggregation between the ENPs and suspended particulate matter resulted in clusters of low variability. These conditions are, therefore, reliable predictors of the eventual fate of the modeled ENPs. The conclusions from this study are also valid for ENP fate in other large river systems. Our results, therefore, shift the focus of future modeling and experimental research of ENP environmental fate to the water characteristic in regions near the expected ENP emission sources. Under conditions favoring heteroaggregation in these

  18. Accumulation and Toxicity of Copper Oxide Engineered Nanoparticles in a Marine Mussel

    PubMed Central

    Hanna, Shannon K.; Miller, Robert J.; Lenihan, Hunter S.

    2014-01-01

    Cu is an essential trace element but can be highly toxic to aquatic organisms at elevated concentrations. Greater use of CuO engineered nanoparticles (ENPs) may lead to increased concentrations of CuO ENPs in aquatic environments causing potential ecological injury. We examined the toxicity of CuO ENPs to marine mussels and the influence of mussels on the fate and transport of CuO ENPs. We exposed marine mussels to 1, 2, or 3 mg L−1 CuO ENPs for four weeks, and measured clearance rate, rejection, excretion and accumulation of Cu, and mussel shell growth. Mussel clearance rate was 48% less, and growth was 68% less, in mussels exposed to 3 mg L−1 than in control animals. Previous studies show 100% mortality at 1 mg Cu L−1, suggesting that CuO ENPs are much less toxic than ionic Cu, probably due to the slow dissolution rate of the ENPs. Mussels rejected and excreted CuO ENPs in biodeposits containing as much as 110 mg Cu g−1, suggesting the potential for magnification in sediments. Mussels exposed to 3 mg L−1 CuO ENPs accumulated 79.14 ± 12.46 μg Cu g−1 dry weight, which was 60 times more Cu than in control animals. Our results suggest that mussels have the potential to influence the fate and transport of CuO ENPs and potentially cause magnification of CuO ENPs in mussel bed communities, creating a significant source of Cu to marine benthos. PMID:28344235

  19. The effects of metallic engineered nanoparticles upon plant systems: An analytic examination of scientific evidence.

    PubMed

    Tolaymat, Thabet; Genaidy, Ash; Abdelraheem, Wael; Dionysiou, Dionysios; Andersen, Christian

    2017-02-01

    Recent evidence for the effects of metallic engineered nanoparticles (ENPs) on plants and plant systems was examined together with its implications for other constituents of the Society-Environment-Economy (SEE) system. In this study, we were particularly interested to determine whether or not metallic ENPs have both stimulatory and inhibitory effects upon plant performance. An emphasis was made to analyze the scientific evidence on investigations examining both types of effects in the same studies. Analysis of evidence demonstrated that metallic ENPs have both stimulatory and inhibitory effects mostly in well-controlled environments and soilless media. Nano zero-valent iron (nZVI) and Cu ENPs have potential for use as micronutrients for plant systems, keeping in mind the proper formulation at the right dose for each type of ENP. The concentration levels for the stimulatory effects of Cu ENPs are lower than for those for nZVI. Newer findings showed that extremely smaller concentrations of Au ENPs (smaller than those for nZVI and Cu ENPs) induce positive effects for plant growth, which is attributed to effects on secondary metabolites. Ag ENPs have demonstrated their usage as antimicrobial/pesticidal agents for plant protection; however, precautions should be taken to avoid higher concentrations not only for plant systems, but also, other constituents in the SEE. Further research is warranted to investigate the stimulatory and inhibitory effects of metallic ENPs in soil media in order to broaden the horizon of sustainable agriculture production in terms of higher and safer yields so as to meet the food requirements of human population.

  20. Coal-fueled high-speed diesel engine development: Task 2, Market assessment and economic analysis

    SciTech Connect

    Not Available

    1991-12-01

    Based on the preliminary coal engine design developed, this task was conducted to identify the best opportunity(s) to enter the market with the future coal-fueled, high-speed diesel engine. The results of this market and economic feasibility assessment will be used to determine what specific heavy duty engine application(s) are most attractive for coal fuel, and also define basic economic targets for the engine to be competitive.

  1. Interlaboratory comparison of size and surface charge measurements on nanoparticles prior to biological impact assessment

    NASA Astrophysics Data System (ADS)

    Roebben, G.; Ramirez-Garcia, S.; Hackley, V. A.; Roesslein, M.; Klaessig, F.; Kestens, V.; Lynch, I.; Garner, C. M.; Rawle, A.; Elder, A.; Colvin, V. L.; Kreyling, W.; Krug, H. F.; Lewicka, Z. A.; McNeil, S.; Nel, A.; Patri, A.; Wick, P.; Wiesner, M.; Xia, T.; Oberdörster, G.; Dawson, K. A.

    2011-07-01

    The International Alliance for NanoEHS Harmonization (IANH) organises interlaboratory comparisons of methods used to study the potential biological impacts of nanomaterials. The aim of IANH is to identify and reduce or remove sources of variability and irreproducibility in existing protocols. Here, we present results of the first IANH round robin studies into methods to assess the size and surface charge of suspended nanoparticles. The test materials used (suspensions of gold, silica, polystyrene, and ceria nanoparticles, with [primary] particles sizes between 10 nm and 80 nm) were first analysed in repeatability conditions to assess the possible contribution of between-sample heterogeneity to the between-laboratory variability. Reproducibility of the selected methods was investigated in an interlaboratory comparison between ten different laboratories in the USA and Europe. Robust statistical analysis was used to evaluate within- and between-laboratory variability. It is shown that, if detailed shipping, measurement, and reporting protocols are followed, measurement of the hydrodynamic particle diameter of nanoparticles in predispersed monomodal suspensions using the dynamic light scattering method is reproducible. On the other hand, measurements of more polydisperse suspensions of nanoparticle aggregates or agglomerates were not reproducible between laboratories. Ultrasonication, which is commonly used to prepare dispersions before cell exposures, was observed to further increase variability. The variability of the zeta potential values, which were also measured, indicates the need to define better surface charge test protocols and to identify sources of variability.

  2. 2014 Abridged Technology and Engineering Literacy Framework for the 2014 National Assessment of Educational Progress

    ERIC Educational Resources Information Center

    National Assessment Governing Board, 2014

    2014-01-01

    Due to the growing importance of technology and engineering in the educational landscape, and to support America's ability to contribute to and compete in a global economy, the National Assessment Governing Board (NAGB) initiated development of the first NAEP Technology and Engineering Literacy (TEL) Assessment. Relating to national efforts in…

  3. The Idaho National Engineering and Environmental Laboratory Source Water Assessment

    SciTech Connect

    Sehlke, G.

    2003-03-17

    The Idaho National Engineering and Environmental Laboratory (INEEL) covers approximately 890 square miles and includes 12 public water systems that must be evaluated for Source water protection purposes under the Safe Drinking Water Act. Because of its size and location, six watersheds and five aquifers could potentially affect the INEEL's drinking water sources. Based on a preliminary evaluation of the available information, it was determined that the Big Lost River, Birch Creek, and Little Lost River Watersheds and the eastern Snake River Plain Aquifer needed to be assessed. These watersheds were delineated using the United States Geologic Survey's Hydrological Unit scheme. Well capture zones were originally estimated using the RESSQC module of the Environmental Protection Agency's Well Head Protection Area model, and the initial modeling assumptions and results were checked by running several scenarios using Modflow modeling. After a technical review, the resulting capture zones were expanded to account for the uncertainties associated with changing groundwater flow directions, a this vadose zone, and other data uncertainties. Finally, all well capture zones at a given facility were merged to a single wellhead protection area at each facility. A contaminant source inventory was conducted, and the results were integrated with the well capture zones, watershed and aquifer information, and facility information using geographic information system technology to complete the INEEL's Source Water Assessment. Of the INEEL's 12 public water systems, three systems rated as low susceptibility (EBR-1, Main Gate, and Gun Range), and the remainder rated as moderate susceptibility. No INEEL public water system rated as high susceptibility. We are using this information to develop a source water management plan from which we will subsequently implement an INEEL-wide source water management program. The results are a very robust set of wellhead protection areas that will protect

  4. Idaho National Engineering Laboratory Consolidated Transportation Facility. Environmental Assessment

    SciTech Connect

    Not Available

    1993-04-01

    The Department of Energy (DOE) has prepared an environmental assessment (EA), DOE/EA-0822, addressing environmental impacts that could result from siting, construction, and operation of a consolidated transportation facility at the Idaho National Engineering Laboratory (INEL) near Idaho Falls, Idaho. The DOE proposes to construct and operate a new transportation facility at the Central Facilities Area (CFA) at the INEL. The proposed facility would replace outdated facilities and consolidate in one location operations that are conducted at six different locations at the CFA. The proposed facility would be used for vehicle and equipment maintenance and repair, administrative support, bus parking, and bus driver accommodation. Based on the analyses in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969, as amended. Therefore, the preparation of an environmental impact statement (EIS) is not required and the Department is issuing this finding of no significant impact.

  5. Stirling engine: Available tools for long-life assessment

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.; Bartolotta, Paul A.

    1991-01-01

    A review is presented for the durability approaches applicable to long-time life assessment of Stirling engine hot-section components. The crucial elements are experimental techniques for generating long-time materials property data (both monotonic and cyclic flow and failure properties); analytic representations of slow strain rate material stress-strain response characteristics (monotonic and cyclic constitutive relations) at high temperatures and low stresses and strains; analytic creep-fatigue-environmental interaction life prediction methods applicable to long lifetimes at high temperatures and small stresses and strains; and experimental verification of life predictions. Long-lifetime design criteria for materials of interest are woefully lacking. Designing against failures due to creep, creep-rupture, fatigue, environmental attack, and creep-fatigue-environmental interaction will require considerable extrapolation. Viscoplastic constitutive models and time-temperature parameters will have to be calibrated for the hot-section materials of interest. Analysis combined with limited verification testing in a short-time regime will be required to build confidence in long-lifetime durability models.

  6. Micro-engineered remote palpation device for assessing tissue compliance.

    PubMed

    Hien, M; Yang, T H J; Leung, S K W; Reuben, R L; Habib, F K; McNeill, S A; Schneider, A; McBride, G; Stevens, R; Else, R W

    2008-01-01

    This paper concerns the operation of the actuator for a prototype micro-engineered mechanical palpation device for deployment via a cystoscope to measure the dynamic mechanical properties of the prostate gland in vivo. The subassembly consists of a 400x200 microm silicon (Si) piston manufactured using deep reactive ion etching (DRIE) housed within an anodically bonded glass-Si-glass sandwiched housing. The micro-channel on the Si layer was formed by powder blasting and contains the micro-piston with one end pointing to the side of the housing and the other facing a via hole leading to a capillary tube. The opening on the side of the housing was sealed by a 5 microm thick silicone membrane which acts to retain the micro-piston and act as a return spring. A 320 microm diameter capillary forms the connection between the micro-channel and a micro-syringe which is operated by a programmable syringe pump to produce a reciprocating action. A pressure sensor is connected along the capillary tube to measure the dynamic pressure within the system. The micro-piston has already been used, separately actuated to measure the dynamic mechanical properties of known viscoelastic materials and prostate tissue. The purpose of the present work is to assess the functionality of the actuator assembly.

  7. Nanoparticle-assay marker interaction: effects on nanotoxicity assessment

    NASA Astrophysics Data System (ADS)

    Zhao, Xinxin; Xiong, Sijing; Huang, Liwen Charlotte; Ng, Kee Woei; Loo, Say Chye Joachim

    2015-01-01

    Protein-based cytotoxicity assays such as lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-α) are commonly used in cytotoxic evaluation of nanoparticles (NPs) despite numerous reports on possible interactions with protein markers in these assays that can confound the results obtained. In this study, conventional cytotoxicity assays where assay markers may (LDH and TNF- α) or may not (PicoGreen and WST-8) come into contact with NPs were used to evaluate the cytotoxicity of NPs. The findings revealed selective interactions between negatively charged protein assay markers (LDH and TNF- α) and positively charged ZnO NPs under abiotic conditions. The adsorption and interaction with these protein assay markers were strongly influenced by surface charge, concentration, and specific surface area of the NPs, thereby resulting in less than accurate cytotoxic measurements, as observed from actual cell viability measurements. An improved protocol for LDH assay was, therefore, proposed and validated by eliminating any effects associated with protein-particle interactions. In view of this, additional measures and precautions should be taken when evaluating cytotoxicity of NPs with standard protein-based assays, particularly when they are of opposite charges.

  8. Gold-plated silver nanoparticles engineered for sensitive plasmonic detection amplified by morphological changes.

    PubMed

    Hobbs, Krysten; Cathcart, Nicole; Kitaev, Vladimir

    2016-07-28

    Gold-plated silver nanoparticles have been developed to undergo morphological changes that enhance the surface plasmon resonance (SPR) sensing response. These morphological changes were realized through thin-frame gold plating that both reinforces the nanoparticle edges and enables partial silver etching upon exposure to several biological molecules, including thiols and amines.

  9. Facile synthesis of Curcuma longa tuber powder engineered metal nanoparticles for bioimaging applications

    NASA Astrophysics Data System (ADS)

    Sankar, Renu; Rahman, Pattanathu K. S. M.; Varunkumar, Krishnamoorthy; Anusha, Chidambaram; Kalaiarasi, Arunachalam; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

    2017-02-01

    Nanomaterials based fluorescent agents are rapidly becoming significant and promising transformative tools for improving medical diagnostics for extensive in vivo imaging modalities. Compared with conventional fluorescent agents, nano-fluorescence has capabilities to improve the in vivo detection and enriched targeting efficiencies. In our laboratory we synthesized fluorescent metal nanoparticles of silver, copper and iron using Curcuma longa tuber powder by simple reduction. The physicochemical properties of the synthesized metal nanoparticles were attained using UV-visible spectrophotometry, scanning electron microscopy with EDAX spectroscopy, dynamic light scattering, Fourier-transform infrared spectroscopy and X-ray diffraction. The Curcuma longa tuber powder has one of the bioactive compound Curcumin might act as a capping agent during the synthesis of nanoparticles. The synthesized metal nanoparticles fluorescence property was confirmed by spectrofluorometry. When compared with copper and iron nanoparticles the silver nanoparticles showed high fluorescence intensity under spectrofluorometry. Moreover, in vitro cell images of the silver nanoparticles in A549 cell lines also correlated with the results of spectrofluorometry. These silver nanoparticles show inspiring cell-imaging applications. They enter into cells without any further modifications, and the fluorescence property can be utilized for fluorescence-based cell imaging applications.

  10. Minimizing of the boundary friction coefficient in automotive engines using Al2O3 and TiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ali, Mohamed Kamal Ahmed; Xianjun, Hou; Elagouz, Ahmed; Essa, F. A.; Abdelkareem, Mohamed A. A.

    2016-12-01

    Minimizing of the boundary friction coefficient is critical for engine efficiency improvement. It is known that the tribological behavior has a major role in controlling the performance of automotive engines in terms of the fuel consumption. The purpose of this research is an experimental study to minimize the boundary friction coefficient via nano-lubricant additives. The tribological characteristics of Al2O3 and TiO2 nano-lubricants were evaluated under reciprocating test conditions to simulate a piston ring/cylinder liner interface in automotive engines. The nanoparticles were suspended in a commercially available lubricant in a concentration of 0.25 wt.% to formulate the nano-lubricants. The Al2O3 and TiO2 nanoparticles had sizes of 8-12 and 10 nm, respectively. The experimental results have shown that the boundary friction coefficient reduced by 35-51% near the top and bottom dead center of the stroke (TDC and BDC) for the Al2O3 and TiO2 nano-lubricants, respectively. The anti-wear mechanism was generated via the formation of protective films on the worn surfaces of the ring and liner. These results will be a promising approach for improving fuel economy in automotive.

  11. Life-cycle assessment framework for indoor emissions of synthetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Walser, Tobias; Meyer, David; Fransman, Wouter; Buist, Harrie; Kuijpers, Eelco; Brouwer, Derk

    2015-06-01

    Life-Cycle Assessment (LCA) is a well-established method to evaluate impacts of chemicals on the environment and human health along the lifespan of products. However, the increasingly produced and applied nanomaterials (defined as one dimension <100 nm) show particular characteristics which are different from conventional chemicals or larger particles. As a consequence, LCA does not provide sufficient guidance on how to deal with synthetic nanomaterials, neither in the exposure, nor in the effect assessment. This is particularly true for the workplace, where significant exposure can be expected via the lung, the route of major concern. Therefore, we developed a concise method which allows the inclusion of indoor nanoparticle exposure into LCA. New nanospecific properties are included along the LCA stages with a particular focus on the workplace environment. We built upon existing LCA methods and nanoparticle fate and exposure studies. The impact assessment requires new approaches for nanoparticles, such as guidance on relevant endpoints, nanospecific properties that are relevant for the toxicity, and guidance on the chemical identity of nanomaterials, i.e., categorization and distinction of different forms of nanomaterials. We present a framework which goes beyond traditional approaches of LCA and includes nanospecific fate parameters in the indoor exposure assessment as well as guidance on the development of effect and characterization factors for inhaled nanoparticles. Specifically, the indoor one-box model is amended with new particle-specific parameters developed in the exposure literature. A concentration conversion and parameter estimation tool are presented. Finally, the modification of the traditional intake fraction to capture size-specific deposition and retention rate are discussed along with a strategy for a more robust effect assessment. The paper is a further step toward a fair comparison between conventional and nano-enabled products by integrating

  12. Application of an asymmetric flow field flow fractionation multi-detector approach for metallic engineered nanoparticle characterization--prospects and limitations demonstrated on Au nanoparticles.

    PubMed

    Hagendorfer, Harald; Kaegi, Ralf; Traber, Jacqueline; Mertens, Stijn F L; Scherrers, Roger; Ludwig, Christian; Ulrich, Andrea

    2011-11-14

    In this work we discuss about the method development, applicability and limitations of an asymmetric flow field flow fractionation (A4F) system in combination with a multi-detector setup consisting of UV/vis, light scattering, and inductively coupled plasma mass spectrometry (ICPMS). The overall aim was to obtain a size dependent-, element specific-, and quantitative method appropriate for the characterization of metallic engineered nanoparticle (ENP) dispersions. Thus, systematic investigations of crucial method parameters were performed by employing well characterized Au nanoparticles (Au-NPs) as a defined model system. For good separation performance, the A4F flow-, membrane-, and carrier conditions were optimized. To obtain reliable size information, the use of laser light scattering based detectors was evaluated, where an online dynamic light scattering (DLS) detector showed good results for the investigated Au-NP up to a size of 80 nm in hydrodynamic diameter. To adapt large sensitivity differences of the various detectors, as well as to guarantee long term stability and minimum contamination of the mass spectrometer a split-flow concept for coupling ICPMS was evaluated. To test for reliable quantification, the ICPMS signal response of ionic Au standards was compared to that of Au-NP. Using proper stabilization with surfactants, no difference for concentrations of 1-50 μg Au L(-1) in the size range from 5 to 80 nm for citrate stabilized dispersions was observed. However, studies using different A4F channel membranes showed unspecific particle-membrane interaction resulting in retention time shifts and unspecific loss of nanoparticles, depending on the Au-NP system as well as membrane batch and type. Thus, reliable quantification and discrimination of ionic and particular species was performed using ICPMS in combination with ultracentrifugation instead of direct quantification with the A4F multi-detector setup. Figures of merit were obtained, by comparing the

  13. Effects of engineered iron nanoparticles on the bryophyte, Physcomitrella patens (Hedw.) Bruch & Schimp, after foliar exposure.

    PubMed

    Canivet, L; Dubot, P; Garçon, G; Denayer, F-O

    2015-03-01

    The effects of iron nanoparticles on bryophytes (Physcomitrella patens) were studied following foliar exposure. We used iron nanoparticles (Fe-NP) representative of industrial emissions from the metallurgical industries. After a characterization of iron nanoparticles and the validation of nanoparticle internalization in cells, the effects (cytotoxicity, oxidative stress, lipid peroxidation of membrane) of iron nanoparticles were determined through the axenic culturing of Physcomitrella patens exposed at five different concentrations (5 ng, 50 ng, 500 ng, 5 µg and 50 µg per plant). Following exposure, the plant health, measured as ATP concentrations, was not impacted. Moreover, we studied oxidative stress in three ways: through the measure of reactive oxygen species (ROS) production, through malondialdehyde (MDA) production and also through glutathione regulation. At concentrations tested over a short period, the level of ROS, MDA and glutathione were not significantly disturbed.

  14. Fatigue Lifetime Assessment of Aircraft Engine Disc via Multi-source Information Fusion

    NASA Astrophysics Data System (ADS)

    Huang, Hong-Zhong; Cui, Ping-Liang; Peng, Weiwen; Gao, Hui-Ying; Wang, Hai-Kun

    2014-06-01

    Fatigue lifetime assessment for aircraft engine discs is an important issue for the operation and health management of aircraft engines. Due to the lack of field test data, traditional methods can hardly meet the requirements of fatigue lifetime assessment of aircraft engine discs. By combining a multi-source information fusion method with a Bayesian inference technique, this paper develops a practical approach for fatigue lifetime assessment of aircraft engine discs. Subjective information and historical data are combined coherently with the sparse test data to generate a credible fatigue lifetime assessment of aircraft engine discs. Methods for quantifying subjective information, checking different experts' information, and fusing multiple prior distributions are presented to facilitate the implementation of fatigue lifetime assessment. An illustrative example is presented to demonstrate the procedures and the implication of the proposed method.

  15. Review: Morphofunctional and biochemical markers of stress in sea urchin life stages exposed to engineered nanoparticles.

    PubMed

    Gambardella, Chiara; Ferrando, Sara; Gatti, Antonietta M; Cataldi, Edoardo; Ramoino, Paola; Aluigi, Maria Grazia; Faimali, Marco; Diaspro, Alberto; Falugi, Carla

    2016-11-01

    We describe the use of different life stages of the Mediterranean sea urchin Paracentrotus lividus for the assessment of the possible risk posed by nanoparticles (NPs) in the coastal water. A first screening for the presence of NPs in sea water may be obtained by checking their presence inside tissues of organisms taken from the wild. The ability of NPs to pass from gut to the coelomic fluid is demonstrated by accumulation in sea urchin coelomocytes; the toxicity on sperms can be measured by embryotoxicity markers after sperm exposure, whereas the transfer through the food chain can be observed by developmental anomalies in larvae fed with microalgae exposed to NPs. The most used spermiotoxicity and embryotoxicity tests are described, as well as the biochemical and histochemical analyses of cholinesterase (ChE) activities, which are used to verify toxicity parameters such as inflammation, neurotoxicity, and interference in cell-to-cell communication. Morphological markers of toxicity, in particular skeletal anomalies, are described and classified. In addition, NPs may impair viability of the immune cells of adult specimens. Molecular similarity between echinoderm and human immune cells is shown and discussed. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1552-1562, 2016.

  16. Development of Comparative Toxicity Potentials of TiO2 Nanoparticles for Use in Life Cycle Assessment.

    PubMed

    Ettrup, Kim; Kounina, Anna; Hansen, Steffen Foss; Meesters, Johannes A J; Vea, Eldbjørg B; Laurent, Alexis

    2017-03-20

    Studies have shown that releases of nanoparticles may take place through the life cycle of products embedding nanomaterials, thus resulting in potential impacts on ecosystems and human health. While several life cycle assessment (LCA) studies have assessed such products, only a few of them have quantitatively addressed the toxic impacts caused by released nanoparticles, thus leading to potential biases in their conclusions. Here, we address this gap and aim to provide a framework for calculating characterization factors or comparative toxicity potentials (CTP) for nanoparticles and derive CTP values for TiO2 nanoparticles (TiO2-NP) for use in LCA. We adapted the USEtox 2.0 consensus model to integrate the SimpleBox4Nano fate model, and we populated the resulting model with TiO2-NP specific data. We thus calculated CTP values for TiO2 nanoparticles for air, water, and soil emission compartments for freshwater ecotoxicity and human toxicity, both cancer effects and noncancer effects. Our results appeared plausible after benchmarking with CTPs for other nanoparticles and substances present in the USEtox database, while large differences were observed with CTP values for TiO2 nanoparticles published in earlier studies. Assumptions, which were performed in those previous studies because of lack of data and knowledge at the time they were made, primarily explain such discrepancies. For future assessment of potential toxic impacts of TiO2 nanoparticles in LCA studies, we therefore recommend the use of our calculated CTP.

  17. Gold nanoparticle-enabled blood test for early stage cancer detection and risk assessment.

    PubMed

    Zheng, Tianyu; Pierre-Pierre, Nickisha; Yan, Xin; Huo, Qun; Almodovar, Alvin J O; Valerio, Felipe; Rivera-Ramirez, Inoel; Griffith, Elizabeth; Decker, David D; Chen, Sixue; Zhu, Ning

    2015-04-01

    When citrate ligands-capped gold nanoparticles are mixed with blood sera, a protein corona is formed on the nanoparticle surface due to the adsorption of various proteins in the blood to the nanoparticles. Using a two-step gold nanoparticle-enabled dynamic light scattering assay, we discovered that the amount of human immunoglobulin G (IgG) in the gold nanoparticle protein corona is increased in prostate cancer patients compared to noncancer controls. Two pilot studies conducted on blood serum samples collected at Florida Hospital and obtained from Prostate Cancer Biorespository Network (PCBN) revealed that the test has a 90-95% specificity and 50% sensitivity in detecting early stage prostate cancer, representing a significant improvement over the current PSA test. The increased amount of human IgG found in the protein corona is believed to be associated with the autoantibodies produced in cancer patients as part of the immunodefense against tumor. Proteomic analysis of the nanoparticle protein corona revealed molecular profile differences between cancer and noncancer serum samples. Autoantibodies and natural antibodies produced in cancer patients in response to tumorigenesis have been found and detected in the blood of many cancer types. The test may be applicable for early detection and risk assessment of a broad spectrum of cancer. This new blood test is simple, low cost, requires only a few drops of blood sample, and the results are obtained within minutes. The test is well suited for screening purpose. More extensive studies are being conducted to further evaluate and validate the clinical potential of the new test.

  18. In Vivo Assessment of Clobetasol Propionate-Loaded Lecithin-Chitosan Nanoparticles for Skin Delivery

    PubMed Central

    Şenyiğit, Taner; Sonvico, Fabio; Rossi, Alessandra; Tekmen, Işıl; Santi, Patrizia; Colombo, Paolo; Nicoli, Sara; Özer, Özgen

    2016-01-01

    The aim of this work was to assess in vivo the anti-inflammatory efficacy and tolerability of clobetasol propionate (CP) loaded lecithin/chitosan nanoparticles incorporated into chitosan gel for topical application (CP 0.005%). As a comparison, a commercial cream (CP 0.05% w/w), and a sodium deoxycholate gel (CP 0.05% w/w) were also evaluated. Lecithin/chitosan nanoparticles were prepared by self-assembling of the components obtained by direct injection of soybean lecithin alcoholic solution containing CP into chitosan aqueous solution. Nanoparticles obtained had a particle size around 250 nm, narrow distribution (polydispersity index below 0.2) and positive surface charge, provided by a superficial layer of the cationic polymer. The nanoparticle suspension was then loaded into a chitosan gel, to obtain a final CP concentration of 0.005%. The anti-inflammatory activity was evaluated using carrageenan-induced hind paw edema test on Wistar rats, the effect of formulations on the barrier property of the stratum corneum were determined using transepidermal water loss measurements (TEWL) and histological analysis was performed to evaluate the possible presence of morphological changes. The results obtained indicate that nanoparticle-in-gel formulation produced significantly higher edema inhibition compared to other formulations tested, although it contained ten times less CP. TEWL measurements also revealed that all formulations have no significant disturbance on the barrier function of skin. Furthermore, histological analysis of rat abdominal skin did not show morphological tissue changes nor cell infiltration signs after application of the formulations. Taken together, the present data show that the use of lecithin/chitosan nanoparticles in chitosan gel as a drug carrier significantly improves the risk-benefit ratio as compared with sodium-deoxycholate gel and commercial cream formulations of CP. PMID:28035957

  19. Precise engineering of dapivirine-loaded nanoparticles for the development of anti-HIV vaginal microbicides.

    PubMed

    das Neves, José; Sarmento, Bruno

    2015-05-01

    Polymeric nanoparticles (NPs) have the potential to provide effective and safe delivery of antiretroviral drugs in the context of prophylactic anti-HIV vaginal microbicides. Dapivirine-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) NPs were produced by an emulsion-solvent evaporation method, optimized for colloidal properties using a 3-factor, 3-level Box-Behnken experimental design, and characterized for drug loading, production yield, morphology, thermal behavior, drug release, in vitro cellular uptake, cytotoxicity and pro-inflammatory potential. Also, drug permeability/membrane retention in well-established HEC-1-A and CaSki cell monolayer models as mediated by NPs was assessed in the absence or presence of mucin. Box-Behnken design allowed optimizing monodisperse 170nm drug-loaded NPs. Drug release experiments showed an initial burst effect up to 4h, followed by sustained 24h release at pH 4.2 and 7.4. NPs were readily taken up by different genital and macrophage cell lines as assessed by fluorescence microscopy. Drug-loaded NPs presented lower or at least similar cytotoxicity as compared to the free drug, with up to around one-log increase in half-maximal cytotoxic concentration values. In all cases, no relevant changes in cell pro-inflammatory cytokine/chemokine production were observed. Dapivirine transport across cell monolayers was significantly decreased when mucin was present at the donor side with either NPs or the free drug, thus evidencing the influence of this natural glycoprotein in membrane permeability. Moreover, drug retention in cell monolayers was significantly higher for NPs in comparison with the free drug. Overall, obtained dapivirine-loaded PLGA NPs possess interesting technological and biological features that may contribute to their use as novel safe and effective vaginal microbicides.

  20. Signal Processing Methods for Liquid Rocket Engine Combustion Spontaneous Stability and Rough Combustion Assessments

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy; Casiano, Matthew; Fischbach, Sean; Hulka, James R.

    2012-01-01

    Liquid rocket engine combustion stability assessments are traditionally broken into three categories: dynamic stability, spontaneous stability, and rough combustion. This work focuses on comparing the spontaneous stability and rough combustion assessments for several liquid engine programs. The techniques used are those developed at Marshall Space Flight Center (MSFC) for the J-2X Workhorse Gas Generator program. Stability assessment data from the Integrated Powerhead Demonstrator (IPD), FASTRAC, and Common Extensible Cryogenic Engine (CECE) programs are compared against previously processed J-2X Gas Generator data. Prior metrics for spontaneous stability assessments are updated based on the compilation of all data sets.

  1. Meta-Assessment in a Project-Based Systems Engineering Course

    ERIC Educational Resources Information Center

    Wengrowicz, Niva; Dori, Yehudit Judy; Dori, Dov

    2017-01-01

    Project-based learning (PBL) facilitates significant learning, but it poses a major assessment challenge for assessing individual content knowledge. We developed and implemented an assessment approach and tool for a mandatory undergraduate systems engineering PBL-based course. We call this type of assessment "student-oriented"…

  2. Integrated probabilistic risk assessment for nanoparticles: the case of nanosilica in food

    NASA Astrophysics Data System (ADS)

    Jacobs, Rianne; van der Voet, Hilko; ter Braak, Cajo J. F.

    2015-06-01

    Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the social acceptance and safe use of nanotechnology. One of the problems with which the risk assessment of nanoparticles is faced is the lack of data, resulting in uncertainty in the risk assessment. We attempt to quantify some of this uncertainty by expanding a previous deterministic study on nanosilica (5-200 nm) in food into a fully integrated probabilistic risk assessment. We use the integrated probabilistic risk assessment method in which statistical distributions and bootstrap methods are used to quantify uncertainty and variability in the risk assessment. Due to the large amount of uncertainty present, this probabilistic method, which separates variability from uncertainty, contributed to a better understandable risk assessment. We found that quantifying the uncertainties did not increase the perceived risk relative to the outcome of the deterministic study. We pinpointed particular aspects of the hazard characterization that contributed most to the total uncertainty in the risk assessment, suggesting that further research would benefit most from obtaining more reliable data on those aspects.

  3. Integrated probabilistic risk assessment for nanoparticles: the case of nanosilica in food.

    PubMed

    Jacobs, Rianne; van der Voet, Hilko; Ter Braak, Cajo J F

    Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the social acceptance and safe use of nanotechnology. One of the problems with which the risk assessment of nanoparticles is faced is the lack of data, resulting in uncertainty in the risk assessment. We attempt to quantify some of this uncertainty by expanding a previous deterministic study on nanosilica (5-200 nm) in food into a fully integrated probabilistic risk assessment. We use the integrated probabilistic risk assessment method in which statistical distributions and bootstrap methods are used to quantify uncertainty and variability in the risk assessment. Due to the large amount of uncertainty present, this probabilistic method, which separates variability from uncertainty, contributed to a better understandable risk assessment. We found that quantifying the uncertainties did not increase the perceived risk relative to the outcome of the deterministic study. We pinpointed particular aspects of the hazard characterization that contributed most to the total uncertainty in the risk assessment, suggesting that further research would benefit most from obtaining more reliable data on those aspects.

  4. Modular Fabrication of Polymer Brush Coated Magnetic Nanoparticles: Engineering the Interface for Targeted Cellular Imaging.

    PubMed

    Oz, Yavuz; Arslan, Mehmet; Gevrek, Tugce N; Sanyal, Rana; Sanyal, Amitav

    2016-08-03

    Development of efficient and rapid protocols for diversification of functional magnetic nanoparticles (MNPs) would enable identification of promising candidates using high-throughput protocols for applications such as diagnostics and cure through early detection and localized delivery. Polymer brush coated magnetic nanoparticles find use in many such applications. A protocol that allows modular diversification of a pool of parent polymer coated nanoparticles will lead to a library of functional materials with improved uniformity. In the present study, polymer brush coated parent magnetic nanoparticles obtained using reversible addition-fragmentation chain transfer (RAFT) polymerization are modified to obtain nanoparticles with different "clickable" groups. In this design, trithiocarbonate group terminated polymer brushes are "grafted from" MNPs using a catechol group bearing initiator. A postpolymerization radical exchange reaction allows installation of "clickable" functional groups like azides and maleimides on the chain ends of the polymers. Thus, modified MNPs can be functionalized using alkyne-containing and thiol-containing moieties like peptides and dyes using the alkyne-azide cycloaddition and the thiol-ene conjugation, respectively. Using the approach outlined here, a cell surface receptor targeting cyclic peptide and a fluorescent dye are attached onto nanoparticle surface. This multifunctional construct allows selective recognition of cancer cells that overexpress integrin receptors. Furthermore, the approach outlined here is not limited to the installation of azide and maleimide functional groups but can be expanded to a variety of "clickable" groups to allow nanoparticle modification using a broad range of chemical conjugations.

  5. Surface-independent antibacterial coating using silver nanoparticle-generating engineered mussel glue.

    PubMed

    Jo, Yun Kee; Seo, Jeong Hyun; Choi, Bong-Hyuk; Kim, Bum Jin; Shin, Hwa Hui; Hwang, Byeong Hee; Cha, Hyung Joon

    2014-11-26

    During implant surgeries, antibacterial agents are needed to prevent bacterial infections, which can cause the formation of biofilms between implanted materials and tissue. Mussel adhesive proteins (MAPs) derived from marine mussels are bioadhesives that show strong adhesion and coating ability on various surfaces even in wet environment. Here, we proposed a novel surface-independent antibacterial coating strategy based on the fusion of MAP to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity. This sticky recombinant fusion protein enabled the efficient coating on target surface and the easy generation of silver nanoparticles on the coated-surface under mild condition. The biosynthesized silver nanoparticles showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria and also revealed good cytocompatibility with mammalian cells. In this coating strategy, MAP-silver binding peptide fusion proteins provide hybrid environment incorporating inorganic silver nanoparticle and simultaneously mediate the interaction of silver nanoparticle with surroundings. Moreover, the silver nanoparticles were fully synthesized on various surfaces including metal, plastic, and glass by a simple, surface-independent coating manner, and they were also successfully synthesized on a nanofiber surface fabricated by electrospinning of the fusion protein. Thus, this facile surface-independent silver nanoparticle-generating antibacterial coating has great potential to be used for the prevention of bacterial infection in diverse biomedical fields.

  6. nanoparticles

    NASA Astrophysics Data System (ADS)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  7. Life Cycle Assessment Framework for Indoor Emissions of Synthetic Nanoparticles

    EPA Science Inventory

    Life-Cycle Assessment (LCA) is a well-established method to evaluate impacts of chemicals on the environment and human health along the lifespan of products. However, the increasingly produced and applied nanomaterials (defined as one dimension <100 nm) show particular characteri...

  8. Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products

    PubMed Central

    Pirela, Sandra V.; Sotiriou, Georgios A.; Bello, Dhimiter; Shafer, Martin; Bunker, Kristin Lee; Castranova, Vincent; Thomas, Treye; Demokritou, Philip

    2015-01-01

    It is well established that printers emit nanoparticles during their operation. To-date, however, the physicochemical and toxicological characterization of “real world” printer-emitted nanoparticles (PEPs) remains incomplete, hampering proper risk assessment efforts. Here, we investigate our earlier hypothesis that engineered nanomaterials (ENMs) are used in toners and ENMs are released during printing (consumer use). Furthermore, we conduct a detailed physicochemical and morphological characterization of PEPs in support of ongoing toxicological assessment. A comprehensive suite of state of the art analytical methods and tools was employed for the physicochemical and morphological characterization of 11 toners widely utilized in printers from major printer manufacturers and their PEPs. We confirmed that a number of ENMs incorporated into toner formulations (e.g., silica, alumina, titania, iron oxide, zinc oxide, copper oxide, cerium oxide, carbon black among others) and released into the air during printing. All evaluated toners contained large amounts of organic carbon (OC, 42–89%), metals/metal oxides (1–33%), and some elemental carbon (EC, 0.33–12%). The PEPs possess a composition similar to that of toner and contained 50–90% OC, 0.001–0.5% EC and 1–3% metals. While the chemistry of the PEPs generally reflected that of their toners, considerable differences are documented indicative of potential transformations taking place during consumer use (printing). We conclude that: (i) Routine incorporation of ENMs in toners classifies them as nano-enabled products (NEPs); (ii) These ENMs become airborne during printing; (iii) The chemistry of PEPs is complex and it reflects that of the toner and paper. This work highlights the importance of understanding life-cycle (LC) nano-EHS implications of NEPs and assessing real world exposures and associated toxicological properties rather than focusing on “raw” materials used in the synthesis of an NEP. PMID

  9. Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products.

    PubMed

    Pirela, Sandra V; Sotiriou, Georgios A; Bello, Dhimiter; Shafer, Martin; Bunker, Kristin Lee; Castranova, Vincent; Thomas, Treye; Demokritou, Philip

    2015-01-01

    It is well established that printers emit nanoparticles during their operation. To-date, however, the physicochemical and toxicological characterization of "real world" printer-emitted nanoparticles (PEPs) remains incomplete, hampering proper risk assessment efforts. Here, we investigate our earlier hypothesis that engineered nanomaterials (ENMs) are used in toners and ENMs are released during printing (consumer use). Furthermore, we conduct a detailed physicochemical and morphological characterization of PEPs in support of ongoing toxicological assessment. A comprehensive suite of state of the art analytical methods and tools was employed for the physicochemical and morphological characterization of 11 toners widely utilized in printers from major printer manufacturers and their PEPs. We confirmed that a number of ENMs incorporated into toner formulations (e.g. silica, alumina, titania, iron oxide, zinc oxide, copper oxide, cerium oxide, carbon black among others) and released into the air during printing. All evaluated toners contained large amounts of organic carbon (OC, 42-89%), metals/metal oxides (1-33%), and some elemental carbon (EC, 0.33-12%). The PEPs possess a composition similar to that of toner and contained 50-90% OC, 0.001-0.5% EC and 1-3% metals. While the chemistry of the PEPs generally reflected that of their toners, considerable differences are documented indicative of potential transformations taking place during consumer use (printing). We conclude that: (i) Routine incorporation of ENMs in toners classifies them as nano-enabled products (NEPs); (ii) These ENMs become airborne during printing; (iii) The chemistry of PEPs is complex and it reflects that of the toner and paper. This work highlights the importance of understanding life-cycle (LC) nano-EHS implications of NEPs and assessing real world exposures and associated toxicological properties rather than focusing on "raw" materials used in the synthesis of an NEP.

  10. Interfacial engineering of nanoparticle systems: Assesment of electron transfer in inter and intrananoparticle photosystems as well as sensing applications

    NASA Astrophysics Data System (ADS)

    Phebus, Bruce Drury

    Electron transfer within nanochemical systems plays a key role in their uses. This body of work looks to better understand the conditions required for electron transport within these nanochemical systems and under what circumstances does it play a role in their use. Assessing electron transfer from aqueous graphene nanoparticles to aqueous ions through observation by quenching photoluminescence pointed to interesting requirements for transfer. Sensitivity was observed down to 1.6x10 -6 M for the most strongly quenching ions. More interesting though was a marked dependence on chemical hardness of the ions, with specific chemical hardness required to quench each graphene quantum dot species. Graphene quantum dots sourced from carbon fiber were observed to quench best with ions near that of 8.50 eV chemical hardness, like that of nickelous ions. Nitrogen doped graphene quantum dots were observed to quench best with ions near 7.70 eV in chemical hardness, like that of mercuric ions. The shift to a lower hardness is also noted in a shift toward lower excitation energy of the nanoparticles. For some ions concentration dependence was observed, with ions increasing PL emission initially then subsequently acting as quenchers. This behavior points to multiple quenching sites on the nanoparticles with different complexation values, some leading to stabilization of the PL emission when complexed. EDTA, ethylenediaminetetraacetic acid, was used as a complexing agent to assess possible recovery of emissions. EDTA was observed to complex ions and recovers some PL emission from some ions, with recovery dependent not only on quenching efficiency of the ion but the complexation constant. The most intriguing behavior was observed for aluminum ions which were observed to further quench with additions of EDTA after a critical point emission started to recover. We ascribe this behavior to multiple complexation sites on the nanoparticles with varied concentration and distinct roles in

  11. Incoming Engineering Students' Self-Assessment of Their Mathematical Background

    ERIC Educational Resources Information Center

    Guner, Necdet

    2013-01-01

    The aim of this study was to develop a tool to measure levels of mathematical knowledge gained in high school, as perceived by incoming engineering students. The study included 657 engineering students in the 2011-2012 academic year. Factor analysis was used to obtain a scale consisting of 47 items (Cronbach Alpha coefficient, 0.975). The…

  12. Assessment of a 40-kilowatt stirling engine for underground mining applications

    NASA Technical Reports Server (NTRS)

    Cairelli, J. E.; Kelm, G. G.; Slaby, J. G.

    1982-01-01

    An assessment of alternative power souces for underground mining applications was performed. A 40-kW Stirling research engine was tested to evaluate its performance and emission characteristics when operated with helium working gas and diesel fuel. The engine, the test facility, and the test procedures are described. Performance and emission data for the engine operating with helium working gas and diesel fuel are reported and compared with data obtained with hydrogen working gas and unleaded gasoline fuel. Helium diesel test results are compared with the characteristics of current diesel engines and other Stirling engines. External surface temperature data are also presented. Emission and temperature results are compared with the Federal requirements for diesel underground mine engines. The durability potential of Stirling engines is discussed on the basis of the experience gaind during the engine tests.

  13. Engineering biomaterial surfaces using nanoparticle assemblies: A new paradigm for modulating cell function

    NASA Astrophysics Data System (ADS)

    Lipski, Anna Marie

    Silica nanoparticles (NP) were investigated as a surface modification medium and their impact on cell function was studied. This work has demonstrated that NP assemblies are suitable for the surface modification of both metal and polymer substrates. Additionally, important surface parameters, such as nano-roughness, charge, and chemistry, can be imparted in a predictable manner. More importantly, by varying the NP size, nano-roughness of a surface can be varied independent of chemistry. Two terminally differentiated mammalian cell types, bovine aortic endothelial cells (BAEC) and murine calvarial osteoblast-like cells (MC3T3-E1), were used to probe the effects of nano-topography on cell proliferation, metabolic activity, spreading, cytoskeletal F-actin alignment, and focal adhesion recruitment. Furthermore, the influence of nano-topography on cell migration was studied using BAEC and human fetal osteoblasts (hFOB). The results suggested that surface nano-rugosity affects cell behavior at various levels and that these effects are cell type specific; however, some clear trends were discerned with respect to F-actin alignment and cell migration. In particular, presentation of nano-features resulted in enhancement of cytoskeletal F-actin alignment along the long axis of the cells in comparison to unmodified glass. With respect to cell migration, increased nano-roughness resulted in decreased migration rates for both BAEC and hFOB. Finally, the potential of nano-rugosity as a mediator of cell differentiation was investigated by following the lineage specific differentiation of human marrow-derived mesenchymal progenitor cells (MPC) on NP-modified 316L stainless steel and titanium substrates. It was observed that NP modification enhanced the differentiation of MPC into an osteogenic lineage and that rugosity appeared to be the dominant factor in directing this differentiation. Thus, coatings composed of silica NPs presented a new paradigm that may lend themselves to

  14. Combustion synthesis and engineering nanoparticles for electronic, structural and superconductor applications. Final report, May 31, 1992--May 30, 1996

    SciTech Connect

    Stangle, G.C.; Schulze, W.A.; Amarakoon, V.R.W.

    1996-05-30

    Dense, nanocrystalline ceramic articles of doped ZrO{sub 2} (for use in solid electrolytes, oxygen sensors, electrode materials, thermal barrier coatings, etc.), BaTiO{sub 3} (for capacitor applications), and YBa{sub 2}Cu{sub 3}O{sub 7-x} (a high-temperature superconductor with uses, e.g., in magnetic flux trapping and high-speed capacitor applications) were prepared by the new nanofabrication process that has been developed in this research program. The process consists of two steps: synthesis of ceramic nanoparticles, and fabrication of dense ceramic articles that possess nanocrystalline features. The synthesis step is capable of producing 10-nanometer-diameter crystallites of doped ZrO{sub 2}, and of being scaled up to kilogram/hour production rates. The fabrication step produced dense, ultrafine-grained articles at significantly reduced sintering temperatures and times--representing a factor of 10-100 reduction in process energy requirements. The process has thus been shown to be technically feasible, while a preliminary engineering cost analysis of a pilot plant-scale version of the process indicates that it is both a cost- and an energy-efficient method of producing nanoparticles and nanocrystalline ceramics from those nanoparticles. One U.S. patent for this process has been allowed, and an additional five (continuation-in-part) applications have been filed. Technology transfer efforts have begun, through ongoing discussions with representatives from three manufacturing concerns.

  15. Hybrid composites made of multiwalled carbon nanotubes functionalized with Fe3O4 nanoparticles for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Cunha, C.; Panseri, S.; Iannazzo, D.; Piperno, A.; Pistone, A.; Fazio, M.; Russo, A.; Marcacci, M.; Galvagno, S.

    2012-11-01

    A straightforward technique for functionalization of multiwalled carbon nanotubes (MWCNTs) with magnetite (Fe3O4) nanoparticles was developed. Iron oxide nanoparticles were deposited on MWCNT surfaces by a deposition-precipitation method using Fe3+/Fe2+ salts precursors in basic solution. The characterizations by HRTEM, XRD, SEM/EDX, AAS and TPR analyses confirmed the successful formation of magnetic iron oxide nanoparticles on the MWCNT surface. Fe3O4/MWCNT hybrid composites were analysed in vitro by incubation with mesenchymal stem cells for 1, 3 and 7 days, either in the presence or absence of a static magnetic field. Analysis of cell proliferation was performed by the MTT assay, quantification of cellular stress was performed by the Lactate Dehydrogenase assay and analysis of cell morphology was performed by actin immunofluorescence and scanning electron microscopy. Results demonstrate that the introduction of magnetite into the MWCNT structure increases biocompatibility of oxidized MWCNTs. In addition, the presence of a static magnetic field further increases Fe3O4/MWCNT influence on cell behaviour. These results demonstrate this novel Fe3O4/MWCNT hybrid composite has good potential for tissue engineering applications.

  16. Recent advances on surface engineering of magnetic iron oxide nanoparticles and their biomedical applications.

    PubMed

    Gupta, Ajay Kumar; Naregalkar, Rohan R; Vaidya, Vikas Deep; Gupta, Mona

    2007-02-01

    Magnetic nanoparticles with appropriate surface coatings are increasingly being used clinically for various biomedical applications, such as magnetic resonance imaging, hyperthermia, drug delivery, tissue repair, cell and tissue targeting and transfection. This is because of the nontoxicity and biocompatibility demand that mainly iron oxide-based materials are predominantly used, despite some attempts to develop 'more magnetic nanomaterials' based on cobalt, nickel, gadolinium and other compounds. For all these applications, the material used for surface coating of the magnetic particles must not only be nontoxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. Magnetic nanoparticles can bind to drugs and an external magnetic field can be applied to trap them in the target site. By attaching the targeting molecules, such as proteins or antibodies, at particles surfaces, the latter may be directed to any cell, tissue or tumor in the body. In this review, different polymers/molecules that can be used for nanoparticle coating to stabilize the suspensions of magnetic nanoparticles under in vitro and in vivo situations are discussed. Some selected proteins/targeting ligands that could be used for derivatizing magnetic nanoparticles are also explored. We have reviewed the various biomedical applications with some of the most recent uses of magnetic nanoparticles for early detection of cancer, diabetes and atherosclerosis.

  17. Comparative Human Health Impact Assessment of Engineered Nanomaterials in the Framework of Life Cycle Assessment.

    PubMed

    Fransman, Wouter; Buist, Harrie; Kuijpers, Eelco; Walser, Tobias; Meyer, David; Zondervan-van den Beuken, Esther; Westerhout, Joost; Klein Entink, Rinke H; Brouwer, Derk H

    2016-09-24

    For safe innovation, knowledge on potential human health impacts is essential. Ideally, these impacts are considered within a larger life-cycle-based context to support sustainable development of new applications and products. A methodological framework that accounts for human health impacts caused by inhalation of engineered nanomaterials (ENMs) in an indoor air environment has been previously developed. The objectives of this study are as follows: (i) evaluate the feasibility of applying the CF framework for NP exposure in the workplace based on currently available data; and (ii) supplement any resulting knowledge gaps with methods and data from the life cycle approach and human risk assessment (LICARA) project to develop a modified case-specific version of the framework that will enable near-term inclusion of NP human health impacts in life cycle assessment (LCA) using a case study involving nanoscale titanium dioxide (nanoTiO2 ). The intent is to enhance typical LCA with elements of regulatory risk assessment, including its more detailed measure of uncertainty. The proof-of-principle demonstration of the framework highlighted the lack of available data for both the workplace emissions and human health effects of ENMs that is needed to calculate generalizable characterization factors using common human health impact assessment practices in LCA. The alternative approach of using intake fractions derived from workplace air concentration measurements and effect factors based on best-available toxicity data supported the current case-by-case approach for assessing the human health life cycle impacts of ENMs. Ultimately, the proposed framework and calculations demonstrate the potential utility of integrating elements of risk assessment with LCA for ENMs once the data are available.

  18. Magnetoconductive maghemite core/polyaniline shell nanoparticles: Physico-chemical and biological assessment.

    PubMed

    Anna, Zasońska Beata; Patrycja, Bober; Petr, Jošt; Petrovský, Eduard; Pavel, Boštík; Daniel, Horák

    2016-05-01

    Nanoparticles of various compositions are increasingly being used in many areas of medicine. The aim of this study was to develop nanoparticles, which would possess both magnetic and conductive properties and, thus improve their suitability for a wider range of biomedical applications. Namely, it would enable both the particle manipulation and imaging using their magnetic properties and simultaneous stimulation of electro-sensitive cell types using their magnetic properties, which can be used in tissue therapy, engineering and as biosensors. Maghemite (γ-Fe2O3) particles were prepared by the co-precipitation of Fe(2+) and Fe(3+) salts with ammonium hydroxide, followed by the controlled oxidation with NaOCl. The polyaniline (PANI) shell on the γ-Fe2O3 nanoparticles was obtained by the polymerization of aniline hydrochloride with ammonium peroxydisulfate in an aqueous solution of poly(N-vinylpyrrolidone) at two reaction temperatures (0 and 25 °C). The resulting γ-Fe2O3&PANI particles were characterized by both the light and transmission electron microscopies, dynamic light scattering, magnetic measurements, UV-vis and energy dispersive X-ray (EDAX) spectroscopy. The size of the starting γ-Fe2O3 particles was 11 nm, that increased to 25 nm after the modification with PANI. The incubation of both the γ-Fe2O3 and γ-Fe2O3&PANI nanoparticles with the human neuroblastoma derived SH-SY5Y cells for 8 days showed neither significant decrease in the cell viability, nor detectable changes in the cell morphology. This indicates, that the particles have no detectable cytotoxicity in cell culture and represent a promising tool for further use in biomedical applications.

  19. Use of a Rapid Cytotoxicity Screening Approach to Engineer a Safer Zinc Oxide Nanoparticle through Iron Doping

    PubMed Central

    George, Saji; Pokhrel, Suman; Xia, Tian; Gilbert, Benjamin; Ji, Zhaoxia; Schowalter, Marco; Rosenauer, Andreas; Damoiseaux, Robert; Bradley, Kenneth A; Mädler, Lutz; Nel, André E

    2014-01-01

    The establishment of verifiably safe nanotechnology requires the development of assessment tools to identify hazardous nanomaterial properties that could be modified to improve nanomaterial safety. While there is a lot of debate of what constitutes appropriate safety screening methods, one approach is to use the assessment of cellular injury pathways to collect knowledge about hazardous material properties that could lead to harm to humans and the environment. We demonstrate the use of a multi-parameter cytotoxicity assay that evaluates toxic oxidative stress to compare the effects of titanium dioxide (TiO2), cerium oxide (CeO2) and zinc oxide (ZnO) nanoparticles in bronchial epithelial and macrophage cell lines. The nanoparticles were chosen based on their volume of production and likelihood of spread to the environment. Among the materials, dissolution of ZnO nanoparticles and Zn2+ release were capable of ROS generation and activation of an integrated cytotoxic pathway that includes intracellular calcium flux, mitochondrial depolarization, and plasma membrane leakage. These responses were chosen based on the compatibility of the fluorescent dyes that contemporaneously assess their response characteristics by a semi-automated epifluorescence procedure. Purposeful reduction of ZnO cytotoxicity was achieved by iron doping, which changed the material matrix to slow Zn2+ release. In summary, we demonstrate the utility of a rapid throughput, integrated biological oxidative stress response pathway to perform hazard ranking of a small batch of metal oxide nanoparticles, in addition to showing how this assay can be used to improve nanosafety by decreasing ZnO dissolution through Fe doping. PMID:20043640

  20. Life cycle cost assessment of future low heat rejection engines

    NASA Technical Reports Server (NTRS)

    Petersen, D. R.

    1986-01-01

    The Adiabatic Diesel Engine Component Development (ADECD) represents a project which has the objective to accelerate the development of highway truck engines with advanced technology aimed at reduced fuel consumption. The project comprises three steps, including the synthesis of a number of engine candidate designs, the coupling of each with a number of systems for utilizing exhaust gas energy, and the evaluation of each combination in terms of desirability. Particular attention is given to the employed evaluation method and the development of this method. The objective of Life Cycle Cost (LCC) evaluation in the ADECD program was to select the best from among 42 different low heat rejection engine (LHRE)/exhaust energy recovery system configurations. The LCC model is discussed along with a maintenance cost model, the evaluation strategy, the selection of parameter ranges, and a full factorial analysis.

  1. Engineering of a novel adjuvant based on lipid-polymer hybrid nanoparticles: A quality-by-design approach.

    PubMed

    Rose, Fabrice; Wern, Jeanette Erbo; Ingvarsson, Pall Thor; van de Weert, Marco; Andersen, Peter; Follmann, Frank; Foged, Camilla

    2015-07-28

    The purpose of this study was to design a novel and versatile adjuvant intended for mucosal vaccination based on biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) modified with the cationic surfactant dimethyldioctadecylammonium (DDA) bromide and the immunopotentiator trehalose-6,6'-dibehenate (TDB) (CAF01) to tailor humoral and cellular immunity characterized by antibodies and Th1/Th17 responses. Such responses are important for the protection against diseases caused by intracellular bacteria such as Chlamydia trachomatis and Mycobacterium tuberculosis. The hybrid NPs were engineered using an oil-in-water single emulsion method and a quality-by-design approach was adopted to define the optimal operating space (OOS). Four critical process parameters (CPPs) were identified, including the acetone concentration in the water phase, the stabilizer [polyvinylalcohol (PVA)] concentration, the lipid-to-total solid ratio, and the total concentration. The CPPs were linked to critical quality attributes consisting of the particle size, polydispersity index (PDI), zeta-potential, thermotropic phase behavior, yield and stability. A central composite face-centered design was performed followed by multiple linear regression analysis. The size, PDI, enthalpy of the phase transition and yield were successfully modeled, whereas the models for the zeta-potential and the stability were poor. Cryo-transmission electron microscopy revealed that the main structural effect on the nanoparticle architecture is caused by the use of PVA, and two different morphologies were identified: i) A PLGA core coated with one or several concentric lipid bilayers, and ii) a PLGA nanoshell encapsulating lipid membrane structures. The optimal formulation, identified from the OOS, was evaluated in vivo. The hybrid NPs induced antibody and Th1/Th17 immune responses that were similar in quality and magnitude to the response induced by DDA/TDB liposomes, showing that the adjuvant

  2. Consideration of interaction between nanoparticles and food components for the safety assessment of nanoparticles following oral exposure: A review.

    PubMed

    Cao, Yi; Li, Juan; Liu, Fang; Li, Xiyue; Jiang, Qin; Cheng, Shanshan; Gu, Yuxiu

    2016-09-01

    Nanoparticles (NPs) are increasingly used in food, and the toxicity of NPs following oral exposure should be carefully assessed to ensure the safety. Indeed, a number of studies have shown that oral exposure to NPs, especially solid NPs, may induce toxicological responses both in vivo and in vitro. However, most of the toxicological studies only used NPs for oral exposure, and the potential interaction between NPs and food components in real life was ignored. In this review, we summarized the relevant studies and suggested that the interaction between NPs and food components may exist by that 1) NPs directly affect nutrients absorption through disruption of microvilli or alteration in expression of nutrient transporter genes; 2) food components directly affect NP absorption through physico-chemical modification; 3) the presence of food components affect oxidative stress induced by NPs. All of these interactions may eventually enhance or reduce the toxicological responses induced by NPs following oral exposure. Studies only using NPs for oral exposure may therefore lead to misinterpretation and underestimation/overestimation of toxicity of NPs, and it is necessary to assess the synergistic effects of NPs in a complex system when considering the safety of NPs used in food.

  3. Stability of engineered nanomaterials in complex aqueous matrices: Settling behaviour of CeO2 nanoparticles in natural surface waters.

    PubMed

    Van Koetsem, Frederik; Verstraete, Simon; Van der Meeren, Paul; Du Laing, Gijs

    2015-10-01

    The stability of engineered nanoparticles (ENPs) in complex aqueous matrices is a key determinant of their fate and potential toxicity towards the aquatic environment and human health. Metal oxide nanoparticles, such as CeO2 ENPs, are increasingly being incorporated into a wide range of industrial and commercial applications, which will undoubtedly result in their (unintentional) release into the environment. Hereby, the behaviour and fate of CeO2 ENPs could potentially serve as model for other nanoparticles that possess similar characteristics. The present study examined the stability and settling of CeO2 ENPs (7.3±1.4 nm) as well as Ce(3+) ions in 10 distinct natural surface waters during 7d, under stagnant and isothermal experimental conditions. Natural water samples were collected throughout Flanders (Belgium) and were thoroughly characterized. For the majority of the surface waters, a substantial depletion (>95%) of the initially added CeO2 ENPs was observed just below the liquid surface of the water samples after 7d. In all cases, the reduction was considerably higher for CeO2 ENPs than for Ce(3+) ions (<68%). A first-order kinetics model was able to describe the observed time-dependant removal of both CeO2 ENPs (R(2)≥0.998) and Ce(3+) ions (R(2)≥0.812) from the water column, at least in case notable sedimentation occurred over time. Solution-pH appeared to be a prime parameter governing nanoparticle colloidal stability. Moreover, the suspended solids (TSS) content also seemed to be an important factor affecting the settling rate and residual fraction of CeO2 ENPs as well as Ce(3+) ions in natural surface waters. Correlation results also suggest potential association and co-precipitation of CeO2 ENPs with aluminium- and iron-containing natural colloidal material. The CeO2 ENPs remained stable in dispersion in surface water characterized by a low pH, ionic strength (IS), and TSS content, indicating the eventual stability and settling behaviour of the

  4. Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications.

    PubMed

    Gupta, Ajay Kumar; Gupta, Mona

    2005-06-01

    Superparamagnetic iron oxide nanoparticles (SPION) with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and in cell separation, etc. All these biomedical and bioengineering applications require that these nanoparticles have high magnetization values and size smaller than 100 nm with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. In addition, these applications need special surface coating of the magnetic particles, which has to be not only non-toxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. To this end, most work in this field has been done in improving the biocompatibility of the materials, but only a few scientific investigations and developments have been carried out in improving the quality of magnetic particles, their size distribution, their shape and surface in addition to characterizing them to get a protocol for the quality control of these particles. Nature of surface coatings and their subsequent geometric arrangement on the nanoparticles determine not only the overall size of the colloid but also play a significant role in biokinetics and biodistribution of nanoparticles in the body. The types of specific coating, or derivatization, for these nanoparticles depend on the end application and should be chosen by keeping a particular application in mind, whether it be aimed at inflammation response or anti-cancer agents. Magnetic nanoparticles can bind to drugs, proteins, enzymes, antibodies, or nucleotides and can be directed to an organ, tissue, or tumour using an external magnetic field or can be heated in alternating magnetic fields for use in hyperthermia. This review discusses the synthetic chemistry, fluid stabilization and

  5. Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

    NASA Astrophysics Data System (ADS)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  6. Toxicological studies on silver nanoparticles: challenges and opportunities in assessment, monitoring and imaging

    PubMed Central

    Stensberg, Matthew Charles; Wei, Qingshan; McLamore, Eric Scott; Porterfield, David Marshall; Wei, Alexander; Sepúlveda, Marĺa Soledad

    2012-01-01

    Silver nanoparticles (Ag NPs) are becoming increasingly prevalent in consumer products as antibacterial agents. The increased use of Ag NP-enhanced products may lead to an increase in toxic levels of environmental silver, but regulatory control over the use or disposal of such products is lagging due to insufficient assessment on the toxicology of Ag NPs and their rate of release into the environment. In this article we discuss recent research on the transport, activity and fate of Ag NPs at the cellular and organismic level, in conjunction with traditional and recently established methods of nanoparticle characterization. We include several proposed mechanisms of cytotoxicity based on such studies, as well as new opportunities for investigating the uptake and fate of Ag NPs in living systems. PMID:21793678

  7. Peer Assessment Learning Sessions (PALS): An Innovative Feedback Technique for Large Engineering Classes

    ERIC Educational Resources Information Center

    O'Moore, Liza; Baldock, Tom

    2007-01-01

    This paper reports the development of innovative assessment sessions within two core technical courses in Civil Engineering at the University of Queensland. Peer Assessment Learning Sessions (PALS) facilitate a student's peer assessment of a colleague's problem-based learning assignment or tutorial within a "traditional" whole-class…

  8. Engineering novel targeted nanoparticle formulations to increase the therapeutic efficacy of conventional chemotherapeutics against multiple myeloma

    NASA Astrophysics Data System (ADS)

    Ashley, Jonathan D.

    Multiple myeloma (MM) is a hematological malignancy which results from the uncontrolled clonal expansion of plasma cells within the body. Despite recent medical advances, this disease remains largely incurable, with a median survival of ˜7 years, owing to the development of drug resistance. This dissertation will explore new advances in nanotechnology that will combine the cytotoxic effects of small molecule chemotherapeutics with the tumor targeting capabilities of nanoparticles to create novel nanoparticle formulations that exhibit enhanced therapeutic indices in the treatment of MM. First, doxorubicin was surfaced conjugated onto micellar nanoparticles via an acid labile hydrazone bond to increase the drug accumulation at the tumor. The cell surface receptor Very Late Antigen-4 (VLA-4; alpha4beta1) is expressed on cancers of hematopoietic origin and plays a vital role in the cell adhesion mediated drug resistance (CAM-DR) in MM. Therefore, VLA-4 antagonist peptides were conjugated onto the nanoparticles via a multifaceted procedure to actively target MM cells and simultaneously inhibit CAM-DR. The micellar doxorubicin nanoparticles were able to overcome CAM-DR and demonstrated improved therapeutic index relative to free doxorubicin. In addition to doxorubicin, other classes of therapeutic agents, such as proteasome inhibitors, can be incorporated in nanoparticles for improved therapeutic outcomes. Utilizing boronic acid chemistry, bortezomib prodrugs were synthesized using a reversible boronic ester bond and then incorporated into liposomes. The different boronic ester bonds that could be potentially used in the synthesis of bortezomib prodrugs were screened based on stability using isobutylboronic acid. The liposomal bortezomib nanoparticles demonstrated significant proteasome inhibition and cytotoxicity in MM cells in vitro, and dramatically reduced the non-specific toxicities associated with free bortezomib while maintaining significant tumor growth

  9. Detecting and Number Counting of Single Engineered Nanoparticles by Digital Particle Polymerase Chain Reaction.

    PubMed

    Paunescu, Daniela; Mora, Carlos A; Querci, Lorenzo; Heckel, Reinhard; Puddu, Michela; Hattendorf, Bodo; Günther, Detlef; Grass, Robert N

    2015-10-27

    The concentrations of nanoparticles present in colloidal dispersions are usually measured and given in mass concentration (e.g. mg/mL), and number concentrations can only be obtained by making assumptions about nanoparticle size and morphology. Additionally traditional nanoparticle concentration measures are not very sensitive, and only the presence/absence of millions/billions of particles occurring together can be obtained. Here, we describe a method, which not only intrinsically results in number concentrations, but is also sensitive enough to count individual nanoparticles, one by one. To make this possible, the sensitivity of the polymerase chain reaction (PCR) was combined with a binary (=0/1, yes/no) measurement arrangement, binomial statistics and DNA comprising monodisperse silica nanoparticles. With this method, individual tagged particles in the range of 60-250 nm could be detected and counted in drinking water in absolute number, utilizing a standard qPCR device within 1.5 h of measurement time. For comparison, the method was validated with single particle inductively coupled plasma mass spectrometry (sp-ICPMS).

  10. Potential for Inhalation Exposure to Engineered Nanoparticles from Nanotechnology-Based Cosmetic Powders

    PubMed Central

    Nazarenko, Yevgen; Zhen, Huajun; Han, Taewon; Lioy, Paul J.

    2012-01-01

    Background: The market of nanotechnology-based consumer products is rapidly expanding, and the lack of scientific evidence describing the accompanying exposure and health risks stalls the discussion regarding its guidance and regulation. Objectives: We investigated the potential for human contact and inhalation exposure to nanomaterials when using nanotechnology-based cosmetic powders and compare them with analogous products not marketed as nanotechnology based. Methods: We characterized the products using transmission electron microscopy (TEM) and laser diffraction spectroscopy and found nanoparticles in five of six tested products. TEM photomicrographs showed highly agglomerated states of nanoparticles in the products. We realistically simulated the use of cosmetic powders by applying them to the face of a human mannequin head while simultaneously sampling the released airborne particles through the ports installed in the mannequin’s nostrils. Results: We found that a user would be exposed to nanomaterial predominantly through nanoparticle-containing agglomerates larger than the 1–100-nm aerosol fraction. Conclusions: Predominant deposition of nanomaterial(s) will occur in the tracheobronchial and head airways—not in the alveolar region as would be expected based on the size of primary nanoparticles. This could potentially lead to different health effects than expected based on the current understanding of nanoparticle behavior and toxicology studies for the alveolar region. PMID:22394622

  11. Assessing Information-Seeking Behavior of Computer Science and Engineering Faculty

    ERIC Educational Resources Information Center

    Tucci, Valerie K.

    2011-01-01

    This study, the first phase of a multi-phase effort, was undertaken to assess and provide for the information needs of the Faculty of the Schools of Science and Engineering at The College of New Jersey (TCNJ) in the digital age. The objectives of this phase were to: 1) gain an in-depth understanding of how computer science and engineering faculty…

  12. Assessing Instructional Documents: A Comparison of Writing Faculty, Engineering Faculty and Workplace Technical Communicator Practices.

    ERIC Educational Resources Information Center

    Napierkowski, Harriet

    A study examined the assessment of instructional documents written by undergraduate engineering students in a 300-level technical writing course. The six documents were independently ranked by nine readers--three writing faculty, three engineering faculty, and three technical writing professionals. Besides ranking the documents, the nine readers…

  13. A Process Analysis of Engineering Problem Solving and Assessment of Problem Solving Skills

    ERIC Educational Resources Information Center

    Grigg, Sarah J.

    2012-01-01

    In the engineering profession, one of the most critical skills to possess is accurate and efficient problem solving. Thus, engineering educators should strive to help students develop skills needed to become competent problem solvers. In order to measure the development of skills, it is necessary to assess student performance, identify any…

  14. A Risk Assessment Architecture for Enhanced Engine Operation

    NASA Technical Reports Server (NTRS)

    Litt, Jonathan S.; Sharp. Lauren M.; Guo, Ten-Huei

    2010-01-01

    On very rare occasions, in-flight emergencies have occurred that required the pilot to utilize the aircraft's capabilities to the fullest extent possible, sometimes using actuators in ways for which they were not intended. For instance, when flight control has been lost due to damage to the hydraulic systems, pilots have had to use engine thrust to maneuver the plane to the ground and in for a landing. To assist the pilot in these situations, research is being performed to enhance the engine operation by making it more responsive or able to generate more thrust. Enabled by modification of the propulsion control, enhanced engine operation can increase the probability of a safe landing during an inflight emergency. However, enhanced engine operation introduces risk as the nominal control limits, such as those on shaft speed, temperature, and acceleration, are exceeded. Therefore, an on-line tool for quantifying this risk must be developed to ensure that the use of an enhanced control mode does not actually increase the overall danger to the aircraft. This paper describes an architecture for the implementation of this tool. It describes the type of data and algorithms required and the information flow, and how the risk based on engine component lifing and operability for enhanced operation is determined.

  15. Assessment of potential asbestos exposures from jet engine overhaul work.

    PubMed

    Mlynarek, S P; Van Orden, D R

    2012-06-01

    Asbestos fibers have been used in a wide variety of products and numerous studies have shown that exposures from the use or manipulation of these products can vary widely. Jet engines contained various components (gaskets, clamps, o-rings and insulation) that contained asbestos that potentially could release airborne fibers during routine maintenance or during an engine overhaul. To evaluate the potential exposures to aircraft mechanics, a Pratt & Whitney JT3D jet engine was obtained and overhauled by experienced mechanics using tools and work practices similar to those used since the time this engine was manufactured. This study has demonstrated that the disturbance of asbestos-containing gaskets, o-rings, and other types of asbestos-containing components, while performing overhaul work to a jet engine produces very few airborne fibers, and that virtually none of these aerosolized fibers is asbestos. The overhaul work was observed to be dirty and oily. The exposures to the mechanics and bystanders were several orders of magnitude below OSHA exposure regulations, both current and historic. The data presented underscore the lack of risk to the health of persons conducting this work and to other persons in proximity to it from airborne asbestos.

  16. Engine panel seals for hypersonic engine applications: High temperature leakage assessments and flow modelling

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M.; Mutharasan, Rajakkannu; Du, Guang-Wu; Miller, Jeffrey H.; Ko, Frank

    1992-01-01

    A critical mechanical system in advanced hypersonic engines is the panel-edge seal system that seals gaps between the articulating horizontal engine panels and the adjacent engine splitter walls. Significant advancements in seal technology are required to meet the extreme demands placed on the seals, including the simultaneous requirements of low leakage, conformable, high temperature, high pressure, sliding operation. In this investigation, the seal concept design and development of two new seal classes that show promise of meeting these demands will be presented. These seals include the ceramic wafer seal and the braided ceramic rope seal. Presented are key elements of leakage flow models for each of these seal types. Flow models such as these help designers to predict performance-robbing parasitic losses past the seals, and estimate purge coolant flow rates. Comparisons are made between measured and predicted leakage rates over a wide range of engine simulated temperatures and pressures, showing good agreement.

  17. Lung dosimetry and risk assessment of nanoparticles: Evaluating and extending current models in rats and humans

    SciTech Connect

    Kuempel, E.D.; Tran, C.L.; Castranova, V.; Bailer, A.J.

    2006-09-15

    Risk assessment of occupational exposure to nanomaterials is needed. Human data are limited, but quantitative data are available from rodent studies. To use these data in risk assessment, a scientifically reasonable approach for extrapolating the rodent data to humans is required. One approach is allometric adjustment for species differences in the relationship between airborne exposure and internal dose. Another approach is lung dosimetry modeling, which provides a biologically-based, mechanistic method to extrapolate doses from animals to humans. However, current mass-based lung dosimetry models may not fully account for differences in the clearance and translocation of nanoparticles. In this article, key steps in quantitative risk assessment are illustrated, using dose-response data in rats chronically exposed to either fine or ultrafine titanium dioxide (TiO{sub 2}), carbon black (CB), or diesel exhaust particulate (DEP). The rat-based estimates of the working lifetime airborne concentrations associated with 0.1% excess risk of lung cancer are approximately 0.07 to 0.3 mg/m{sup 3} for ultrafine TiO{sub 2}, CB, or DEP, and 0.7 to 1.3 mg/m{sup 3} for fine TiO{sub 2}. Comparison of observed versus model-predicted lung burdens in rats shows that the dosimetry models predict reasonably well the retained mass lung burdens of fine or ultrafine poorly soluble particles in rats exposed by chronic inhalation. Additional model validation is needed for nanoparticles of varying characteristics, as well as extension of these models to include particle translocation to organs beyond the lungs. Such analyses would provide improved prediction of nanoparticle dose for risk assessment.

  18. R and D needs assessment for the Engineering Test Facility

    SciTech Connect

    Not Available

    1980-10-01

    The Engineering Test Facility (ETF), planned to be the next major US magnetic fusion device, has its mission (1) to provide the capability for moving into the engineering phase of fusion development and (2) to provide a test-bed for reactor components in a fusion environment. The design, construction, and operation of the ETF requires an increasing emphasis on certain key research and development (R and D) programs in magnetic fusion in order to provide the necessary facility design base. This report identifies these needs and discusses the apparent inadequacies of the presently planned US program to meet them, commensurate with the ETF schedule.

  19. Preliminary Assessment of a Rotary Detonation Engine Concept.

    DTIC Science & Technology

    1983-09-01

    S3RSUYIN STATEMENT W 4 s~u do""d to afo 8% of mftsew= kenamoe) IL. 31uiP901111TAINY WOME Detonation Combustion Rotary Engine Intermittent Detonation Engine...There are several features to be noted. Mixture com- ponents entered separately from the right via valves 1, 2, and 3, entering the horizontally mounted...Mixing chamber pressure was indicated on the right . Both gages indicated in terms of absolute pressures with a range of zero to thirty psia. The mixed

  20. Surface engineering of Co and FeCo nanoparticles for biomedical application

    NASA Astrophysics Data System (ADS)

    Behrens, Silke; Bönnemann, Helmut; Matoussevitch, Nina; Gorschinski, Angelika; Dinjus, Eckhard; Habicht, Wilhelm; Bolle, Jens; Zinoveva, Svetlana; Palina, Natalie; Hormes, Josef; Modrow, Hartwig; Bahr, Stephan; Kempter, Volker

    2006-09-01

    Monodisperse Co, Fe, and FeCo nanoparticles are prepared via thermal decomposition of metal carbonyls in the presence of aluminium alkyls, yielding air-stable magnetic metal nanoparticles after surface passivation. The particles are characterized by electron microscopy (SEM, TEM, ESI), electron spectroscopy (MIES, UPS, and XPS) and x-ray absorption spectroscopy (EXAFS). The particles are peptized by surfactants to form stable magnetic fluids in various organic media and water, exhibiting a high volume concentration and a high saturation magnetization. In view of potential biomedical applications of the particles, several procedures for surface modification are presented, including peptization by functional organic molecules, silanization, and in situ polymerization.

  1. In situ assessment of the contact angles of nanoparticles adsorbed at fluid interfaces by multiple angle of incidence ellipsometry.

    PubMed

    Stocco, Antonio; Su, Ge; Nobili, Maurizio; In, Martin; Wang, Dayang

    2014-09-28

    Here multiple angle of incidence ellipsometry was successfully applied to in situ assess the contact angle and surface coverage of gold nanoparticles as small as 18 nm, coated with stimuli-responsive polymers, at water-oil and water-air interfaces in the presence of NaCl and NaOH, respectively. The interfacial adsorption of the nanoparticles was found to be very slow and took days to reach a fairly low surface coverage. For water-oil interfaces, in situ nanoparticle contact angles agree with the macroscopic equilibrium contact angles of planar gold surfaces with the same polymer coatings, whilst for water-air interfaces, significant differences have been observed.

  2. Assessing Engineering Competencies: The Conditions for Educational Improvement

    ERIC Educational Resources Information Center

    Musekamp, Frank; Pearce, Jacob

    2015-01-01

    Low-stakes assessment is supposed to improve educational practice by providing feedback to different actors in educational systems. However, the process of assessment from design to the point of a final impact on student learning outcomes is complex and diverse. It is hard to identify reasons for substandard achievement on assessments, let alone…

  3. Developing Instrumentation for Assessing Creativity in Engineering Design

    ERIC Educational Resources Information Center

    Denson, Cameron D.; Buelin, Jennifer K.; Lammi, Matthew D.; D'Amico, Susan

    2015-01-01

    A perceived inability to assess creative attributes of students' work has often precluded creativity instruction in the classroom. The Consensual Assessment Technique (CAT) has shown promise in a variety of domains for its potential as a valid and reliable means of creativity assessment. Relying upon an operational definition of creativity and a…

  4. Assess/Mitigate Risk through the Use of Computer-Aided Software Engineering (CASE) Tools

    NASA Technical Reports Server (NTRS)

    Aguilar, Michael L.

    2013-01-01

    The NASA Engineering and Safety Center (NESC) was requested to perform an independent assessment of the mitigation of the Constellation Program (CxP) Risk 4421 through the use of computer-aided software engineering (CASE) tools. With the cancellation of the CxP, the assessment goals were modified to capture lessons learned and best practices in the use of CASE tools. The assessment goal was to prepare the next program for the use of these CASE tools. The outcome of the assessment is contained in this document.

  5. Creation of Novel Solid-Solution Alloy Nanoparticles on the Basis of Density-of-States Engineering by Interelement Fusion.

    PubMed

    Kobayashi, Hirokazu; Kusada, Kohei; Kitagawa, Hiroshi

    2015-06-16

    Currently 118 known elements are represented in the periodic table. Of these 118 elements, only about 80 elements are stable, nonradioactive, and widely available for our society. From the viewpoint of the "elements strategy", we need to make full use of the 80 elements to bring out their latent ability and create innovative materials. Furthermore, there is a strong demand that the use of rare or toxic elements be reduced or replaced while their important properties are retained. Advanced science and technology could create higher-performance materials even while replacing or reducing minor or harmful elements through the combination of more abundant elements. The properties of elements are correlated directly with their electronic states. In a solid, the magnitude of the density of states (DOS) at the Fermi level affects the physical and chemical properties. In the present age, more attention has been paid to improving the properties of materials by means of alloying elements. In particular, the solid-solution-type alloy is advantageous because the properties can be continuously controlled by tuning the compositions and/or combinations of the constituent elements. However, the majority of bulk alloys are of the phase-separated type under ambient conditions, where constituent elements are immiscible with each other. To overcome the challenge of the bulk-phase metallurgical aspects, we have focused on the nanosize effect and developed methods involving "nonequilibrium synthesis" or "a process of hydrogen absorption/desorption". We propose a new concept of "density-of-states engineering" for the design of materials having the most desirable and suitable properties by means of "interelement fusion". In this Account, we describe novel solid-solution alloys of Pd-Pt, Ag-Rh, and Pd-Ru systems in which the constituent elements are immiscible in the bulk state. The homogeneous solid-solution alloys of Pd and Pt were created from Pd core/Pt shell nanoparticles using a

  6. Commercial Automotive Engine Oils - A Laboratory Assessment of Their Quality.

    DTIC Science & Technology

    1979-12-01

    were to procure off-the-shelf re-branded oils of at least American Petroleum Institute (API) * ISE performance level and falling into the Society of...requirement. 14 APPENDIX COMMERCIAL ENGINE OIL PERFORMANCE CLASSIFICATIONS In 1947, the American Petroleum Institute (API) adopted the first

  7. Assessing Proficiency in Engineering and Technology within a Multidisciplinary Curriculum

    ERIC Educational Resources Information Center

    Forest, James JF; Keith, Bruce

    2004-01-01

    The United States Military Academy (USMA) provides cadets with the intellectual foundation that they will need to succeed as military officers. The abilities to shape the physical world and to lead others in doing so are important competences of an Army officer. Therefore, the study of engineering and technology is fundamental to the education of…

  8. A gene network simulator to assess reverse engineering algorithms.

    PubMed

    Di Camillo, Barbara; Toffolo, Gianna; Cobelli, Claudio

    2009-03-01

    In the context of reverse engineering of biological networks, simulators are helpful to test and compare the accuracy of different reverse-engineering approaches in a variety of experimental conditions. A novel gene-network simulator is presented that resembles some of the main features of transcriptional regulatory networks related to topology, interaction among regulators of transcription, and expression dynamics. The simulator generates network topology according to the current knowledge of biological network organization, including scale-free distribution of the connectivity and clustering coefficient independent of the number of nodes in the network. It uses fuzzy logic to represent interactions among the regulators of each gene, integrated with differential equations to generate continuous data, comparable to real data for variety and dynamic complexity. Finally, the simulator accounts for saturation in the response to regulation and transcription activation thresholds and shows robustness to perturbations. It therefore provides a reliable and versatile test bed for reverse engineering algorithms applied to microarray data. Since the simulator describes regulatory interactions and expression dynamics as two distinct, although interconnected aspects of regulation, it can also be used to test reverse engineering approaches that use both microarray and protein-protein interaction data in the process of learning. A first software release is available at http://www.dei.unipd.it/~dicamill/software/netsim as an R programming language package.

  9. Sequential Assessment of Engineering Design Projects at University Level

    ERIC Educational Resources Information Center

    Oehlers, Deric John

    2006-01-01

    Seven years of industrial experience followed by 30 years of academic research and teaching in structural engineering have led the author to believe that the prime objective of a university design course is not the design project itself but to train students to solve problems, as this will last them throughout their careers. It is shown how design…

  10. Hotspots engineering by grafting Au@Ag core-shell nanoparticles on the Au film over slightly etched nanoparticles substrate for on-site paraquat sensing.

    PubMed

    Wang, Chaoguang; Wu, Xuezhong; Dong, Peitao; Chen, Jian; Xiao, Rui

    2016-12-15

    Paraquat (PQ) pollutions are ultra-toxic to human beings and hard to be decomposed in the environment, thus requiring an on-site detection strategy. Herein, we developed a robust and rapid PQ sensing strategy based on the surface-enhanced Raman scattering (SERS) technique. A hybrid SERS substrate was prepared by grafting the Au@Ag core-shell nanoparticles (NPs) on the Au film over slightly etched nanoparticles (Au FOSEN). Hotspots were engineered at the junctions as indicated by the finite difference time domain calculation. SERS performance of the hybrid substrate was explored using p-ATP as the Raman probe. The hybrid substrate gives higher enhancement factor comparing to either the Au FOSEN substrate or the Au@Ag core-shell NPs, and exhibits excellent reproducibility, homogeneity and stability. The proposed SERS substrates were prepared in batches for the practical PQ sensing. The total analysis time for a single sample, including the pre-treatment and measurement, was less than 5min with a PQ detection limit of 10nM. Peak intensities of the SERS signal were plotted as a function of the PQ concentrations to calibrate the sensitivity by fitting the Hill's equation. The plotted calibration curve showed a good log-log linearity with the coefficient of determination of 0.98. The selectivity of the sensing proposal was based on the "finger print" Raman spectra of the analyte. The proposed substrate exhibited good recovery when it applied to real water samples, including lab tap water, bottled water, and commercially obtained apple juice and grape juice. This SERS-based PQ detection method is simple, rapid, sensitive and selective, which shows great potential in pesticide residue and additives abuse monitoring.

  11. Low temperature thermal engineering of nanoparticle ink for flexible electronics applications

    NASA Astrophysics Data System (ADS)

    Ko, Seung Hwan

    2016-07-01

    Flexible electronics are getting a lot of attention for future electronics due to their flexibility and light weight. Flexible electronics are usually fabricated on heat sensitive flexible substrates such as plastic, fabric or even paper. Therefore, the successful fabrication of flexible electronics needs a novel low temperature process development for metal circuit patterning on flexible substrates because the traditional photolithography process usually uses multiple stages of very high temperature steps for metal deposition and patterning and corrosive chemicals. In this paper, the recent novel development based on nanoparticle ink for effective deposition and patterning of high resolution metal patterns on heat sensitive, low cost and light weight plastic substrates at low temperature and in ambient pressure without using any expensive, toxic and time consuming lithographic processes will be reviewed. Nanoparticles exhibit many remarkable characteristics that are significantly different from the bulk counter parts. Nanoparticles shows size dependent melting temperature drop due to the thermodynamics size effect. These novel thermal characteristics of nanoparticles are very important for flexible electronics fabrication process development.

  12. Evaluation of the Seismic Characterision of Select Engineered Nanoparticles in Saturated Glass Beads

    EPA Science Inventory

    A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline si...

  13. Tangential Flow Filtration of Colloidal Silver Nanoparticles: A "Green" Laboratory Experiment for Chemistry and Engineering Students

    ERIC Educational Resources Information Center

    Dorney, Kevin M.; Baker, Joshua D.; Edwards, Michelle L.; Kanel, Sushil R.; O'Malley, Matthew; Pavel Sizemore, Ioana E.

    2014-01-01

    Numerous nanoparticle (NP) fabrication methodologies employ "bottom-up" syntheses, which may result in heterogeneous mixtures of NPs or may require toxic capping agents to reduce NP polydispersity. Tangential flow filtration (TFF) is an alternative "green" technique for the purification, concentration, and size-selection of…

  14. H2O2-responsive molecularly engineered polymer nanoparticles as ischemia/reperfusion-targeted nanotherapeutic agents

    NASA Astrophysics Data System (ADS)

    Lee, Dongwon; Bae, Soochan; Hong, Donghyun; Lim, Hyungsuk; Yoon, Joo Heung; Hwang, On; Park, Seunggyu; Ke, Qingen; Khang, Gilson; Kang, Peter M.

    2013-07-01

    The main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury is the overproduction of reactive oxygen species (ROS). Hydrogen peroxide (H2O2), the most abundant form of ROS produced during I/R, causes inflammation, apoptosis and subsequent tissue damages. Here, we report H2O2-responsive antioxidant nanoparticles formulated from copolyoxalate containing vanillyl alcohol (VA) (PVAX) as a novel I/R-targeted nanotherapeutic agent. PVAX was designed to incorporate VA and H2O2-responsive peroxalate ester linkages covalently in its backbone. PVAX nanoparticles therefore degrade and release VA, which is able to reduce the generation of ROS, and exert anti-inflammatory and anti-apoptotic activity. In hind-limb I/R and liver I/R models in mice, PVAX nanoparticles specifically reacted with overproduced H2O2 and exerted highly potent anti-inflammatory and anti-apoptotic activities that reduced cellular damages. Therefore, PVAX nanoparticles have tremendous potential as nanotherapeutic agents for I/R injury and H2O2-associated diseases.

  15. Exploiting Fast Exciton Diffusion in Dye-Doped Polymer Nanoparticles to Engineer Efficient Photoswitching.

    PubMed

    Trofymchuk, Kateryna; Prodi, Luca; Reisch, Andreas; Mély, Yves; Altenhöner, Kai; Mattay, Jochen; Klymchenko, Andrey S

    2015-06-18

    Photoswitching of bright fluorescent nanoparticles opens new possibilities for bioimaging with superior temporal and spatial resolution. However, efficient photoswitching of nanoparticles is hard to achieve using Förster resonance energy transfer (FRET) to a photochromic dye, because the particle size is usually larger than the Förster radius. Here, we propose to exploit the exciton diffusion within the FRET donor dyes to boost photoswitching efficiency in dye-doped polymer nanoparticles. To this end, we utilized bulky hydrophobic counterions that prevent self-quenching and favor communication of octadecyl rhodamine B dyes inside a polymer matrix of poly(D,L-lactide-co-glycolide). Among tested counterions, only perfluorinated tetraphenylborate that favors the exciton diffusion enables high photoswitching efficiency (on/off ratio ∼20). The switching improves with donor dye loading and requires only 0.1-0.3 wt % of a diphenylethene photochromic dye. Our nanoparticles were validated both in solution and at the single-particle level. The proposed concept paves the way to new efficient photoswitchable nanomaterials.

  16. Diagnostic and Condition Monitoring System Assessment for Army Helicopter Modular Turboshaft Engines.

    DTIC Science & Technology

    1980-10-01

    and Condition Monitoring METS Modular Engine Test System MPFI Modular Performance F-4ult Isolation MTBF Mean Time Between Failures MTTR Mean Time to...AO-ACO? 31b GENERAL ELECTRIC CO LYNN MA AIRCRAFT ENGINE GROUP F/G 91/5 DIASNObIC AND CONDITION MONITORING SYSTEM ASSESSMENT FOR ARMY -ETCIU) OCT 80 H...1AIN)Il.A AD A-oft LEV t DIAGNOSTIC £ CONDITION MONITORING SYSTEM ASSESSMENT FOR ARMY HELICOPTER MODULAR TURBOSHAFT ENGINES. Harold J. Jord n General

  17. Hepatoprotective effect of engineered silver nanoparticles coated bioactive compounds against diethylnitrosamine induced hepatocarcinogenesis in experimental mice.

    PubMed

    Prasannaraj, Govindaraj; Venkatachalam, Perumal

    2017-02-01

    Nanoparticle based drug delivery can rapidly improves the therapeutic potential of anti-cancer agents. The present study focused to evaluate the hepatoprotective activity of silver nanoparticles (AgNPs) synthesized using aqueous extracts of Andrographis paniculata leaves (ApAgNPs) and Semecarpus anacardium nuts (SaAgNPs) against diethylnitrosamine (DEN) induced liver cancer in mice model. The physico-chemical properties of synthesized AgNPs were characterized by Fourier transform infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX) spectrum, Zeta potential and Dynamic Light Scattering (DLS) analysis. The surface plasmon resonance (SPR) absorption spectrum revealed a strong peak at 420nm for both SaAgNPs and ApAgNPs. FTIR results exhibited the presence of possible functional groups in the synthesized AgNPs. TEM analysis determined the hexagonal, and spherical shape of the synthesized silver nanoparticles. The XRD and SAED pattern confirmed the crystalline nature and crystalline size of the AgNPs. EDX result clearly showed strong silver signals in the range between 2 and 4keV. Zeta potential measurements indicated a sharp peak at -3.93 and -13.8mV for ApAgNPs and SaAgNPs, respectively. DLS measurement expressed the particle size distribution was 70 and 60nm for ApAgNPs and SaAgNPs, respectively. DEN (20mg/kg b.wt.) was subjected to induce liver cancer in mice for 8weeks and treated with biosynthesized silver nanoparticles. Interestingly, ApAgNPs and SaAgNPs treated DEN induced animal groups show a decreased level of aspartate amino transferase (AST), alanine amino transferase (ALT), serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) activity and elevated level of catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) activity over untreated DEN control

  18. Engineering triiodothyronine (T3) nanoparticle for use in ischemic brain stroke.

    PubMed

    Mdzinarishvili, Alexander; Sutariya, Vijaykumar; Talasila, Phani K; Geldenhuys, Werner J; Sadana, Prabodh

    2013-08-01

    A potential means of pharmacological management of ischemic stroke is rapid intervention using potent neuroprotective agents. Thyroid hormone (T3) has been shown to protect against ischemic damage in middle cerebral artery occlusion (MCAO) model of ischemic brain stroke. While thyroid hormone is permeable across the blood-brain barrier, we hypothesized that efficacy of thyroid hormone in ischemic brain stroke can be enhanced by encapsulation in nanoparticulate delivery vehicles. We tested our hypothesis by generating poly-(lactide-co-glycolide)-polyethyleneglycol (PLGA-b-PEG) nanoparticles that are either coated with glutathione or are not coated. We have previously reported that glutathione coating of PLGA-PEG nanoparticles is an efficient means of brain targeted drug delivery. Encapsulation of T3 in PLGA-PEG delivery vehicle resulted in particles that were in the nano range and exhibited a zeta potential of -6.51 mV (uncoated) or -1.70 mV (coated). We observed that both glutathione-coated and uncoated nanoparticles are taken up in cells wherein they stimulated the expression of thyroid hormone response element driven reporter robustly. In MCAO model of ischemic stroke, significant benefit of administering T3 in nanoparticulate form was observed over injection of a T3 solution. A 34 % decrease in tissue infarction and a 59 % decrease in brain edema were seen upon administration of T3 solution in MCAO stroke model. Corresponding measurements for uncoated T3 nanoparticles were 51 % and 68 %, whereas for the glutathione coated were 58 % and 75 %. Our study demonstrates that using nanoparticle formulations can significantly improve the efficacy of neuroprotective drugs in ischemic brain stroke.

  19. An experimental assessment of toxic potential of nanoparticle preparation of heavy metals in streptozotocin induced diabetes.

    PubMed

    Gandhi, Sonia; Srinivasan, B P; Akarte, Atul Sureshrao

    2013-11-01

    Nanoparticle preparations of heavy metals have attracted enormous scientific and technological interest. Biologically produced nanoparticle preparations of heavy metals are elaborately described in traditional texts and being widely prescribed. The underlying interactions of nano preparations within the physiological fluids are key feature to understand their biological impact. In this perspective, we performed an experimental assessment of the toxicity potential of a marketed metallic preparation named Vasant Kusumakar Ras (VKR), wherein different heavy metals in composite form are reduced to nanoparticle size to produce the desired effect in diabetes and its complications. VKR (50mg/kg) was administered to Albino Wistar rats rendered diabetic using streptozotocin (90mg/kg) in 2 days old neonates. Anti-hyperglycemic effect was observed with VKR along with increased levels of plasma insulin. Renal variables including total proteins and albumin along with glomerular filtration rate were found to improve biochemically. The results were supplemented by effects on different inflammatory and growth factors like TNF-α, nitric oxide, TGF-β and VEGF. However, the results observed in kidney histopathology were not in accordance with the biochemical parameters. Inflammation observed in kidney was confirmed by immunostaining metallothionein, which was due to the accumulation of heavy metals. Furthermore, mercury accumulation in kidney further confirmed by autometallography, which activated mononuclear phagocyte system, which generated an immune response. This was further supported by increase in the extent of apoptosis in kidney tissues. In conclusion, nanoparticle preparations of heavy metals can be toxic to kidney if it is not regulated with respect to its surface chemistry and dosage.

  20. Assessment of airborne nanoparticles present in industry of aluminum surface treatments.

    PubMed

    Santos, R J; Vieira, M T

    2017-03-01

    Conventional industrial processes are emission sources of unintended nanoparticles which are potentially harmful for the environment and human health. The aim of this study is to assess airborne nanoparticle release from aluminum surface treatment processes in various workplaces. Two direct reading instruments, a scanning mobility particle sizer to measure size distribution and a nanoparticle surface area monitoring to measure the surface area of particles deposited in the human lung, were employed to perform area monitoring. The lacquering paint was the process which released the highest concentration of particles from 10-487 nm (7.06 × 10(6) particles/cm(3)). The lacquering baths process emitted particles of the largest average size (76.9 nm) and the largest surface area deposited in the human lung (167.4 µm(2)/cm(3)). Conversely, the anodizing bath process generated particles of the smallest average size (44.3 nm) and the lowest human lung-deposited surface area (1.2 µm(2)/cm(3)). The total number of particles and the surface area can only be fairly correlated for environments in which the surface area presented higher values. The transmission electron microscopy analysis confirmed the presence of aluminum oxide particles of different dimensions near the LB and AB areas and polymeric-based particles near the LP areas. The findings of this study indicated that lacquering and anodizing surface treatments are indeed responsible for the emission of airborne nanoparticles. It also highlights the importance of control strategies as a means of protecting workers' health and environment.

  1. Science/Engineering Education Division assessment activities: An overview. Annual report, FY 1993

    SciTech Connect

    Not Available

    1994-02-01

    Evaluation and assessment of employment trends and education programs are important functions of the Science/Engineering Education Division (SEED). Objectives of SEED`s evaluation and assessment activities are to provide quantitative measures of the impact of programs on participants; assess programmatic achievements; provide valuable information for continued program operation; ensure that the programs meet their objectives; develop and maintain data bases on scientific and engineering employment and education; provide information about trends in employment and education for energy-related scientists and engineers; and provide analyses of energy-related science and engineering employment requirements, future labor market trends, adequacy of supply of new graduates, and implications for education programs. Whenever possible, data are collected that are consistent with information obtained by other national surveys to facilitate comparisons to national norms.

  2. Conducting SEI (Software Engineering Institute)-Assisted Software Process Assessments

    DTIC Science & Technology

    1989-02-01

    Agresti, W.W., "Applying Industrial Engineering to the Software Development Process," Proceedings, IEEE Fall COMPCON, Washington, DC: IEEE Com- puter...information. CMU/SEI-89-TR-7 1.2. Software Process Maturity Framework A software process maturity framework was developed by the SEI for two purposes : to pro...training. The purpose of this briefing is to give SEI team members a good understanding of the organization and the types of software it develops . Typical

  3. Plasmonic effect of Ag nanoparticles in a SiON antireflective coating: engineering rules and physical barrier

    NASA Astrophysics Data System (ADS)

    Lecler, S.; Bastide, S.; Tan, J.; Qu, M.; Slaoui, A.; Fix, T.

    2016-10-01

    Surface plasmon polaritons have been proposed in the architectures of several solar cells as a way to enhance light collection and thus to increase their efficiency. Here, Ag nanoparticles (NPs) are embedded in a SiON antireflective layer using an electroless technique. The plasmonic effects are modeled and observed experimentally for NPs 5 to 200 nm in size. The systematic comparison of scattering and extinction efficiencies computed as a function of the NPs and surrounding medium properties allows establishing engineering rules, validated by the experimental measurements. The fact that Ag NPs larger than 30 nm mainly contribute to light scattering and therefore to optical path enlargement (green-red light), whereas those smaller than 15 nm absorb light by light trapping (blue-green), is demonstrated and physically explained. A physical barrier making it impossible to shift the dominant resonance beyond 650 nm is pointed out.

  4. Long-term effects of engineered nanoparticles on enzyme activity and functional bacteria in wastewater treatment plants.

    PubMed

    Zheng, Xiong; Huang, Haining; Su, Yinglong; Wei, Yuanyuan; Chen, Yinguang

    2015-01-01

    The pervasive use of engineered nanoparticles (NPs) in a wide range of fields raises concerns about their potential environmental impacts. Previous studies confirmed that some NPs had already entered wastewater treatment plants (WWTPs). Wastewater nutrient removal depends on the metabolisms of activated sludge bacteria and their related key enzymes. Therefore, this study compared the possible influences of Al2O3, SiO2, TiO2, and ZnO NPs on the key enzymes activities and microbial community structures involved in wastewater treatment facilities. It was found that long-term exposure to these NPs significantly affected the microbial communities and changed the relative abundances of key functional bacteria, such as ammonia-oxidizing bacteria. Also, the gene expressions and catalytic activities of essential enzymes, such as ammonia monooxygenase, nitrite oxidoreductase, nitrate reductase, and nitrite reductase, were decreased, which finally resulted in a lower efficiency of biological nitrogen removal.

  5. PEGylated nanoparticles bind to and alter amyloid-beta peptide conformation: toward engineering of functional nanomedicines for Alzheimer's disease.

    PubMed

    Brambilla, Davide; Verpillot, Romain; Le Droumaguet, Benjamin; Nicolas, Julien; Taverna, Myriam; Kóňa, Juraj; Lettiero, Barbara; Hashemi, S Hossein; De Kimpe, Line; Canovi, Mara; Gobbi, Marco; Nicolas, Valérie; Scheper, Wiep; Moghimi, S Moein; Tvaroška, Igor; Couvreur, Patrick; Andrieux, Karine

    2012-07-24

    We have demonstrated that the polyethylene glycol (PEG) corona of long-circulating polymeric nanoparticles (NPs) favors interaction with the amyloid-beta (Aβ(1-42)) peptide both in solution and in serum. The influence of PEGylation of poly(alkyl cyanoacrylate) and poly(lactic acid) NPs on the interaction with monomeric and soluble oligomeric forms of Aβ(1-42) peptide was demonstrated by capillary electrophoresis, surface plasmon resonance, thioflavin T assay, and confocal microscopy, where the binding affected peptide aggregation kinetics. The capture of peptide by NPs in serum was also evidenced by fluorescence spectroscopy and ELISA. Moreover, in silico and modeling experiments highlighted the mode of PEG interaction with the Aβ(1-42) peptide and its conformational changes at the nanoparticle surface. Finally, Aβ(1-42) peptide binding to NPs affected neither complement activation in serum nor apolipoprotein-E (Apo-E) adsorption from the serum. These observations have crucial implications in NP safety and clearance kinetics from the blood. Apo-E deposition is of prime importance since it can also interact with the Aβ(1-42) peptide and increase the affinity of NPs for the peptide in the blood. Collectively, our results suggest that these engineered long-circulating NPs may have the ability to capture the toxic forms of the Aβ(1-42) peptide from the systemic circulation and potentially improve Alzheimer's disease condition through the proposed "sink effect".

  6. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering.

    PubMed

    Le, Thi Duy Hanh; Bonani, Walter; Speranza, Giorgio; Sglavo, Vincenzo; Ceccato, Riccardo; Maniglio, Devid; Motta, Antonella; Migliaresi, Claudio

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions.

  7. An Overview of ICT-Based Assessment for Engineering Education

    ERIC Educational Resources Information Center

    Heap, Nick W.; Kear, Karen L.; Bissell, Chris C.

    2004-01-01

    A well-designed assessment strategy can motivate students, and help teachers and institutions to support deep learning. In contrast, inappropriate forms of assessment may promote surface learning, and will therefore fail to support the true goals of education. Recent theories of learning stress the value of dialogue, negotiation and feedback.…

  8. Strategy for the lowering and the assessment of exposure to nanoparticles at workspace - Case of study concerning the potential emission of nanoparticles of Lead in an epitaxy laboratory

    NASA Astrophysics Data System (ADS)

    Artous, Sébastien; Zimmermann, Eric; Douissard, Paul-Antoine; Locatelli, Dominique; Motellier, Sylvie; Derrough, Samir

    2015-05-01

    The implementation in many products of manufactured nanoparticles is growing fast and raises new questions. For this purpose, the CEA - NanoSafety Platform is developing various research topics for health and safety, environment and nanoparticles exposure in professional activities. The containment optimisation for the exposition lowering, then the exposure assessment to nanoparticles is a strategy for safety improvement at workplace and workspace. The lowering step consists in an optimisation of dynamic and static containment at workplace and/or workspace. Generally, the exposure risk due to the presence of nanoparticles substances does not allow modifying the parameters of containment at workplace and/or workspace. Therefore, gaseous or nanoparticulate tracers are used to evaluate performances of containment. Using a tracer allows to modify safely the parameters of the dynamic containment (ventilation, flow, speed) and to study several configurations of static containment. Moreover, a tracer allows simulating accidental or incidental situation. As a result, a safety procedure can be written more easily in order to manage this type of situation. The step of measurement and characterization of aerosols can therefore be used to assess the exposition at workplace and workspace. The case of study, aim of this paper, concerns the potential emission of Lead nanoparticles at the exhaust of a furnace in an epitaxy laboratory. The use of Helium tracer to evaluate the performance of containment is firstly studied. Secondly, the exposure assessment is characterised in accordance with the French guide “recommendations for characterizing potential emissions and exposure to aerosols released from nanomaterials in workplace operations”. Thirdly the aerosols are sampled, on several places, using collection membranes to try to detect traces of Lead in air.

  9. A Rapid Screen Technique for Estimating Nanoparticle Transport in Porous Media

    EPA Science Inventory

    Quantifying the mobility of engineered nanoparticles in hydrologic pathways from point of release to human or ecological receptors is essential for assessing environmental exposures. Column transport experiments are a widely used technique to estimate the transport parameters of ...

  10. Vault Nanoparticles Engineered with the Protein Transduction Domain, TAT48, Enhances Cellular Uptake

    PubMed Central

    Yang, Jian; Srinivasan, Aswin; Sun, Yang; Mrazek, Jan; Shu, Zhanyong; Kickhoefer, Valerie A.

    2013-01-01

    Vaults are naturally-occurring ribonucleoprotein particles found in nearly all eukaryotic cells. They were named for their morphological resemblance to the vaulted ceilings of gothic cathedrals. These ubiquitous nanoparticles are quite abundant with 104-106 copies found in the cytoplasm depending on cell type. The structural shell of the particle can self-assemble from 78 copies of a single protein, the major vault protein. This finding has allowed vaults to be bioengineered, resulting in a variety of new functions and capabilities directed toward overcoming many limitations posed by current gene and drug delivery systems. In this study, we demonstrate that recombinant vaults, with the addition of a cell penetration peptide, TAT, can be rapidly delivered to cells in vitro with significantly elevated binding and uptake efficiency. This TAT-vault nanoparticle could be a valuable tool for improving the retention and penetration of therapeutic drugs at tumor sites. PMID:22785558

  11. Surface engineered nanoparticles for improved surface enhanced Raman scattering applications and method for preparing same

    DOEpatents

    Simmons, Blake A.; Talin, Albert Alec

    2009-11-27

    A method for producing metal nanoparticles that when associated with an analyte material will generate an amplified SERS spectrum when the analyte material is illuminated by a light source and a spectrum is recorded. The method for preparing the metal nanoparticles comprises the steps of (i) forming a water-in-oil microemulsion comprising a bulk oil phase, a dilute water phase, and one or more surfactants, wherein the water phase comprises a transition metal ion; (ii) adding an aqueous solution comprising a mild reducing agent to the water-in-oil microemulsion; (iii) stirring the water-in-oil microemulsion and aqueous solution to initiate a reduction reaction resulting in the formation of a fine precipitate dispersed in the water-in-oil microemulsion; and (iv) separating the precipitate from the water-in-oil microemulsion.

  12. Fe3O4 nanoparticles engineered for plasmid DNA delivery to Escherichia coli

    NASA Astrophysics Data System (ADS)

    Saei, Amir Ata; Barzegari, Abolfazl; Majd, Mostafa Heidari; Asgari, Davoud; Omidi, Yadollah

    2014-08-01

    Heat shock treatment is the most popular method for transformation of Escherichia coli. We have used 19-nm Fe3O4 nanoparticles for improving heat shock protocol. PGEM- T (3,000 bp) and pCAMBIA (8,428 bp) were used as test plasmids for transformation of competent E. coli cells (strains DH5α and Jm107) obtained from heat shock- and CaCl2-treated bacteria. A combination of heat shock and Fe3O4 nanoparticles led to a significant increase (6-10 fold) in number of transformed colonies in comparison with heat shock alone. The percent increase in transformation efficiency was higher for larger pCAMBIA plasmids compared to PGEM- T. The transformation efficiency decreased in the absence of CaCl2 and increased by addition of glycerol to the bacterial culture.

  13. A novel method for assessing the toxicity of silver nanoparticles in Caenorhabditis elegans.

    PubMed

    Luo, Xun; Xu, Shengmin; Yang, Yaning; Zhang, Yajun; Wang, Shunchang; Chen, Shaopeng; Xu, An; Wu, Lijun

    2017-02-01

    At present, nanotechnology has been producing nanoscale materials with unprecedented speed. Nanomaterials could be inevitably released into the environment owing to their widespread use, and their potential toxicity has caused a great concern. With regard to assessment of nanomaterial toxicity, many studies probably don't truly reflect their toxicity, because the nanoparticles were not stable and uniformly dispersed in the medium. In the present study, the semi-fluid nematode growth gelrite medium (NGG) was used to achieve better distribution of silver nanoparticles (AgNPs). We aimed to evaluate the toxicity of AgNPs in three different culture methods, such as the NGG, nematode growth medium (NGM) and K-medium (KM). Our transmission electron microscopy, hydrodynamic diameter, and inductively coupled plasma-atomic emission spectrometry results demonstrated that AgNPs homogeneously and stably dispersed in NGG compared to that in liquid KM. Furthermore, the conventional toxicity end points, such as body length, fecundity, lifespan, population growth, germline cell apoptosis, reactive oxygen species, and mitochondrial membrane potential were used to assess the toxicity of AgNPs to Caenorhabditis elegans (C. elegans) in NGG, NGM and KM. Our results showed that the toxicity of AgNPs obtained in the NGG test medium was much higher than that in the standard NGM and KM. In addition to the improved dispersion of nanoparticles, NGG also offered advantages for long-term studies and likely provided a convenient nematode toxicity testing method. These results revealed that the NGG test medium was a suitable and sensitive culture method for the evaluation of AgNPs toxicity using C. elegans.

  14. The Role of Feedback in E-Assessments for Engineering Education

    ERIC Educational Resources Information Center

    Limniou, Maria; Smith, Michael

    2014-01-01

    The aim of this investigation was to compare two differently designed e-assessments (formative assessments) which supported the same engineering courses for two academic years. In this investigation two group of students participated (Control Group: CG and Experimental Group: EG). The teachers followed exactly the same teaching approach using the…

  15. Assessing Graduate Engineering Programs with ePortfolios: A Comprehensive Design Process

    ERIC Educational Resources Information Center

    Kajfez, Rachael L.; Mohammadi-Aragh, Mahnas J.; Brown, Philip R.; Mann, Katharine A.; Carrico, Cheryl A.; Cross, Kelly J.; Janeski, John A.; McNair, Lisa D.

    2013-01-01

    ePortfolios (ePs) have been used in a variety of applications ranging from undergraduate assessment to graduate student work showcases. We hypothesize that the flexible, individualized nature of ePs makes them suitable assessment tools for graduate engineering programs, which are likewise flexible and individualized. Our investigation resulted in…

  16. Implementing Assessment Engineering in the Uniform Certified Public Accountant (CPA) Examination

    ERIC Educational Resources Information Center

    Burke, Matthew; Devore, Richard; Stopek, Josh

    2013-01-01

    This paper describes efforts to bring principled assessment design to a large-scale, high-stakes licensure examination by employing the frameworks of Assessment Engineering (AE), the Revised Bloom's Taxonomy (RBT), and Cognitive Task Analysis (CTA). The Uniform CPA Examination is practice-oriented and focuses on the skills of accounting. In…

  17. A Study of STEM Assessments in Engineering, Science, and Mathematics for Elementary and Middle School Students

    ERIC Educational Resources Information Center

    Harwell, Michael; Moreno, Mario; Phillips, Alison; Guzey, S. Selcen; Moore, Tamara J.; Roehrig, Gillian H.

    2015-01-01

    The purpose of this study was to develop, scale, and validate assessments in engineering, science, and mathematics with grade appropriate items that were sensitive to the curriculum developed by teachers. The use of item response theory to assess item functioning was a focus of the study. The work is part of a larger project focused on increasing…

  18. Assessing Cognitive Load Theory to Improve Student Learning for Mechanical Engineers

    ERIC Educational Resources Information Center

    Impelluso, Thomas J.

    2009-01-01

    A computer programming class for students of mechanical engineering was redesigned and assessed: Cognitive Load Theory was used to redesign the content; online technologies were used to redesign the delivery. Student learning improved and the dropout rate was reduced. This article reports on both attitudinal and objective assessment: comparing…

  19. WASTE MINIZATION OPPORTUNITY ASSESSMENT: NAVAL UNDERSEA WARFARE ENGINEERING STATION - KEYPORT, WA

    EPA Science Inventory

    This report describes the application of EPA's waste minimization assessment procedures to a torpedo maintenance facility at the Naval Undersea Warfare Engineering Station, Keyport, WA. he assessment focused on the Mark 48 shop and the Mark 46 shop. hese shops service the Mark 48...

  20. A Preliminary Assessment of Corps of Engineers’ Reservoirs, Their Purposes and Susceptibility to Drought

    DTIC Science & Technology

    1990-12-01

    2 Reservoir Purposes ............................................ 6 NATIONAL ASSESSMENT...Water Resources, Corps of Engineers was given the responsibility for what has become known as the National Study of Water Management During Drought. As...made both national and regional assessments possible, the reservoir data for the analyses and much helpful information were provided by personnel

  1. Assessment of Self-Efficacy in Systems Engineering as an Indicator of Competency Level Achievement

    DTIC Science & Technology

    2014-06-01

    instruments that measured self -efficacy, career indecision, self - esteem , expressed vocational interests, and range of perceived vocational options in...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited ASSESSMENT OF SELF ...2014 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE ASSESSMENT OF SELF -EFFICACY IN SYSTEMS ENGINEERING AS AN INDICATOR OF

  2. Student Motivation in Low-Stakes Assessment Contexts: An Exploratory Analysis in Engineering Mechanics

    ERIC Educational Resources Information Center

    Musekamp, Frank; Pearce, Jacob

    2016-01-01

    The goal of this paper is to examine the relationship of student motivation and achievement in low-stakes assessment contexts. Using Pearson product-moment correlations and hierarchical linear regression modelling to analyse data on 794 tertiary students who undertook a low-stakes engineering mechanics assessment (along with the questionnaire of…

  3. Self-Assessment and Reflection in a 1st Semester Course for Software Engineering Students

    ERIC Educational Resources Information Center

    Nielsen, Jacob; Majgaard, Gunver; Sørensen, Erik

    2013-01-01

    How can student self-assessment be used as a tool and become beneficial for both lecturers and students? We used a simple self-assessment tool for pre- and post-testing on a first-semester engineering course. The students graded their knowledge on human-computer interaction based on their ability to understand and explain specific concepts. The…

  4. Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles

    DTIC Science & Technology

    2007-06-01

    have spread to regional lymph nodes (stage III). Overall, 50% of surgically treated patients sufferCorresponding author: Fortina, P. (paolo.fortina...Detection of lymph node involvement in hematologic malignancies using micromagnetic resonance lymphan- giography with a gadolinum-labeled dendrimer...nanoparticle. Neoplasia 7, 984–991 42 Kobayashi, H. et al. (2004) Lymphatic drainage imaging of breast cancer in mice by micro-magnetic resonance

  5. Control of the interparticle spacing in superparamagnetic iron oxide nanoparticle clusters by surface ligand engineering

    NASA Astrophysics Data System (ADS)

    Dan, Wang; Bingbing, Lin; Taipeng, Shen; Jun, Wu; Fuhua, Hao; Chunchao, Xia; Qiyong, Gong; Huiru, Tang; Bin, Song; Hua, Ai

    2016-07-01

    Polymer-mediated self-assembly of superparamagnetic iron oxide (SPIO) nanoparticles allows modulation of the structure of SPIO nanocrystal cluster and their magnetic properties. In this study, dopamine-functionalized polyesters (DA-polyester) were used to directly control the magnetic nanoparticle spacing and its effect on magnetic resonance relaxation properties of these clusters was investigated. Monodisperse SPIO nanocrystals with different surface coating materials (poly(ɛ-caprolactone), poly(lactic acid)) of different molecular weights containing dopamine (DA) structure (DA-PCL2k, DA-PCL1k, DA-PLA1k)) were prepared via ligand exchange reaction, and these nanocrystals were encapsulated inside amphiphilic polymer micelles to modulate the SPIO nanocrystal interparticle spacing. Small-angle x-ray scattering (SAXS) was applied to quantify the interparticle spacing of SPIO clusters. The results demonstrated that the tailored magnetic nanoparticle clusters featured controllable interparticle spacing providing directly by the different surface coating of SPIO nanocrystals. Systematic modulation of SPIO nanocrystal interparticle spacing can regulate the saturation magnetization (M s) and T 2 relaxation of the aggregation, and lead to increased magnetic resonance (MR) relaxation properties with decreased interparticle spacing. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB933903), the National Key Technology R&D Program of China (Grant No. 2012BAI23B08), and the National Natural Science Foundation of China (Grant Nos. 20974065, 51173117, and 50830107).

  6. Engineered nanoparticles against MDR in cancer: The state of the art and its prospective

    PubMed Central

    Greig, Nigel H.; Kamal, Mohammad Amjad; Midoux, Patrick; Pichon, Chantal

    2016-01-01

    Cancer is a highly heterogeneous disease, both within a single patient as well as between patients, and is the leading cause of death worldwide. A variety of mono and combinational therapies, including chemotherapy, have been developed and refined over recent years for its effective treatment. However, the evolution of chemotherapeutic resistance or multidrug resistance (MDR) in cancer has become a major challenge to successful chemotherapy. MDR is a complex process that combines multifaceted non-cellular and cellular-based mechanisms. Research in the area of cancer nanotechnology over the past two decades has reached the point where smartly designed nanoparticles with targeting ligands can aid successful chemotherapy by preferentially accumulating within the tumor region through means of active and passive targeting to overcome MDR, and simultaneously reduce the off-target accumulation of their payload. Such nanoparticle formulations – sometimes termed nanomedicines - are at different stages of cancer clinical trials and show promise in resistant cases. Nanoparticles as chemotherapeutics carriers provide the opportunity to have multiple payloads of drug and/or imaging agents for combinational and theranostic therapy. Moreover, nanotechnology has the potential to combine new treatment strategies, such as near-infrared (NIR), magnetic resonance imaging (MRI), and high intensity focused ultrasound (HIFU) into cancer chemotherapy and imaging. Here we discuss the cellular/non-cellular factors that underpin MDR in cancer, and the potential of nanomedicines to combat MDR, along with recent advances in combining nanotechnology with other approaches in cancer therapy. PMID:27319945

  7. Engineering a well-ordered, functional protein-gold nanoparticle assembly.

    PubMed

    Cheung-Lau, Jasmina C; Liu, Dage; Pulsipher, Katherine W; Liu, Weiren; Dmochowski, Ivan J

    2014-01-01

    The study of interactions between proteins and nanoparticles is important to advancing applications of nanoparticles in biology, medicine, and materials science. Here, we report the encapsulation of a 5-nm diameter gold nanoparticle (AuNP) by thermophilic ferritin (tF), achieved in nearly quantitative yield under mild conditions that preserved the secondary structure, ferroxidase activity, and thermal stability of the native, 4-helix bundle protein subunits. Chromatography-based assays determined that stable protein assembly around AuNPs occurred on long time scales (~48h) and was reversible. Apparent association constants were determined at 25°C for equilibrated tF-BSPP-capped AuNP samples (KA=(2.1±0.4)×10(78)M(-11)) and compared favorably to salt-assembled tF samples (KA=(2.2±0.5)×10(68)M(-11)) at the same protein concentration (0.3mg/mL). Finally, addition of gold ions and mild reducing agent to the tF-AuNP assembly produced 8-nm diameter AuNPs with surface plasmon resonance band unchanged at 520nm, indicative of templating by the protein shell.

  8. Image processing for safety assessment in civil engineering.

    PubMed

    Ferrer, Belen; Pomares, Juan C; Irles, Ramon; Espinosa, Julian; Mas, David

    2013-06-20

    Behavior analysis of construction safety systems is of fundamental importance to avoid accidental injuries. Traditionally, measurements of dynamic actions in civil engineering have been done through accelerometers, but high-speed cameras and image processing techniques can play an important role in this area. Here, we propose using morphological image filtering and Hough transform on high-speed video sequence as tools for dynamic measurements on that field. The presented method is applied to obtain the trajectory and acceleration of a cylindrical ballast falling from a building and trapped by a thread net. Results show that safety recommendations given in construction codes can be potentially dangerous for workers.

  9. Decision Topology Assessment in Engineering Design Under Uncertainity

    DTIC Science & Technology

    2014-01-01

    ORGANIZATION NAME(S) AND ADDRESS(ES) Mechanical Engineering Department,Oakland University,2200 N. Squirrel Road,Rochester,Mi,48309 8. PERFORMING ORGANIZATION...not need to satisfy the grounding condition (see Abbas, 2009). SADTs can be thus used to generate MADTs. As a result, when SADTs are available, one...correctly. Notice that the U of Eq. (9) does not satisfy the grounding condition; i.e., it is not equal to zero when one of the attributes is at its

  10. The workload book: Assessment of operator workload to engineering systems

    NASA Technical Reports Server (NTRS)

    Gopher, D.

    1983-01-01

    The structure and initial work performed toward the creation of a handbook for workload analysis directed at the operational community of engineers and human factors psychologists are described. The goal, when complete, will be to make accessible to such individuals the results of theoretically-based research that are of practical interest and utility in the analysis and prediction of operator workload in advanced and existing systems. In addition, the results of laboratory study focused on the development of a subjective rating technique for workload that is based on psychophysical scaling techniques are described.

  11. Toxicological assessment of TiO2 nanoparticles by recombinant Escherichia coli bacteria.

    PubMed

    Jiang, Guoxiang; Shen, Zhenyao; Niu, Junfeng; Bao, Yueping; Chen, Jing; He, Tiande

    2011-01-01

    Rapid and efficient methods to assess nanoparticle toxicity are desired in current research. Here we showed that Escherichia coli labeled by green fluorescent protein can be a good model bacterium for assessing acute toxicity of TiO(2) (about 50% inhibition ratios after 135 min exposure). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that TiO(2) nanoparticles (NPs) can influence certain protein expression in the recombinant bacterium, and the obvious effects in repressed expression and elevated expression were observed in 30/40, 10/20 μg mL(-1) treated cells, respectively. However, the GFP expression (27 kD) was not influenced by introduced TiO(2) NPs. The change of the fluorescence intensity may be caused by the damage in folding and chromophore formation of the GFP post-translational modification due to generated reactive oxygen species. Furthermore, TiO(2) NPs at higher concentrations decreased their toxicity because of aggregation. 20 μg mL(-1) humic acid (HA) introduced to the medium can decrease the fluorescent inhibition owing to the barrier of steric hindrance it provides between NPs and cells.

  12. Assessment of total silver and silver nanoparticle extraction from medical devices.

    PubMed

    Sussman, Eric M; Jayanti, Priyanka; Dair, Benita J; Casey, Brendan J

    2015-11-01

    There is concern over the release of silver nanoparticles (AgNPs) from medical devices due to their potential toxicological consequences inside the body. Towards developing the exposure component of a risk assessment model, the purpose of this study was to determine the amount and physical form of silver released from medical devices. Scanning electron microscopy was used to confirm that three of five marketed medical devices contained nanosilver coatings (mean feature sizes 115-341 nm). Aqueous device extracts (water, saline and human plasma) were analyzed with inductively coupled plasma mass spectrometry, ultraviolet-visible spectroscopy, dynamic light scattering, transmission electron microscopy, and nanoparticle tracking analysis. The amount of silver extracted from the devices ranged from 1 × 10(-1) to 1 × 10(6) ng/cm(2) (conditions ranged from 37 to 50 °C, over one hour to seven days). The results further indicated that one of the five devices (labeled MD1) released significantly more AgNPs than the other devices. This data suggests that some but not all devices that are formulated with nanosilver may release detectable levels of AgNPs upon extraction. Further work is underway to quantitate the proportion of silver released as AgNPs and to incorporate this data into a risk assessment for AgNP exposure from medical devices.

  13. Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing

    SciTech Connect

    Anast, Kurt Roy

    2015-11-18

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 aboveground UNS, and 79 candidate belowground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  14. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    SciTech Connect

    Anast, Kurt Roy

    2015-11-13

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  15. Nanofibrous poly(lactide-co-glycolide) membranes loaded with diamond nanoparticles as promising substrates for bone tissue engineering

    PubMed Central

    Parizek, Martin; Douglas, Timothy EL; Novotna, Katarina; Kromka, Alexander; Brady, Mariea A; Renzing, Andrea; Voss, Eske; Jarosova, Marketa; Palatinus, Lukas; Tesarek, Pavel; Ryparova, Pavla; Lisa, Věra; dos Santos, Ana M; Bacakova, Lucie

    2012-01-01

    Background Nanofibrous scaffolds loaded with bioactive nanoparticles are promising materials for bone tissue engineering. Methods In this study, composite nanofibrous membranes containing a copolymer of L-lactide and glycolide (PLGA) and diamond nanoparticles were fabricated by an electrospinning technique. PLGA was dissolved in a mixture of methylene chloride and dimethyl formamide (2:3) at a concentration of 2.3 wt%, and nanodiamond (ND) powder was added at a concentration of 0.7 wt% (about 23 wt% in dry PLGA). Results In the composite scaffolds, the ND particles were either arranged like beads in the central part of the fibers or formed clusters protruding from the fibers. In the PLGA-ND membranes, the fibers were thicker (diameter 270 ± 9 nm) than in pure PLGA meshes (diameter 218 ± 4 nm), but the areas of pores among these fibers were smaller than in pure PLGA samples (0.46 ± 0.02 μm2 versus 1.28 ± 0.09 μm2 in pure PLGA samples). The PLGA-ND membranes showed higher mechanical resistance, as demonstrated by rupture tests of load and deflection of rupture probe at failure. Both types of membranes enabled the attachment, spreading, and subsequent proliferation of human osteoblast-like MG-63 cells to a similar extent, although these values were usually lower than on polystyrene dishes. Nevertheless, the cells on both types of membranes were polygonal or spindle-like in shape, and were distributed homogeneously on the samples. From days 1–7 after seeding, their number rose continuously, and at the end of the experiment, these cells were able to create a confluent layer. At the same time, the cell viability, evaluated by a LIVE/DEAD viability/cytotoxicity kit, ranged from 92% to 97% on both types of membranes. In addition, on PLGA-ND membranes, the cells formed well developed talin-containing focal adhesion plaques. As estimated by the determination of tumor necrosis factor-alpha levels in the culture medium and concentration of intercellular adhesion

  16. Risk assessment of amorphous silicon dioxide nanoparticles in a glass cleaner formulation

    PubMed Central

    Scheel, Julia; Karsten, Stefan; Stelter, Norbert; Wind, Thorsten

    2013-01-01

    Since nanomaterials are a heterogeneous group of substances used in various applications, risk assessment needs to be done on a case-by-case basis. Here the authors assess the risk (hazard and exposure) of a glass cleaner with synthetic amorphous silicon dioxide (SAS) nanoparticles during production and consumer use (spray application). As the colloidal material used is similar to previously investigated SAS, the hazard profile was considered to be comparable. Overall, SAS has a low toxicity. Worker exposure was analysed to be well controlled. The particle size distribution indicated that the aerosol droplets were in a size range not expected to reach the alveoli. Predictive modelling was used to approximate external exposure concentrations. Consumer and environmental exposure were estimated conservatively and were not of concern. It was concluded based on the available weight-of-evidence that the production and application of the glass cleaner is safe for humans and the environment under intended use conditions. PMID:22548260

  17. Risk assessment of amorphous silicon dioxide nanoparticles in a glass cleaner formulation.

    PubMed

    Michel, Karin; Scheel, Julia; Karsten, Stefan; Stelter, Norbert; Wind, Thorsten

    2013-08-01

    Since nanomaterials are a heterogeneous group of substances used in various applications, risk assessment needs to be done on a case-by-case basis. Here the authors assess the risk (hazard and exposure) of a glass cleaner with synthetic amorphous silicon dioxide (SAS) nanoparticles during production and consumer use (spray application). As the colloidal material used is similar to previously investigated SAS, the hazard profile was considered to be comparable. Overall, SAS has a low toxicity. Worker exposure was analysed to be well controlled. The particle size distribution indicated that the aerosol droplets were in a size range not expected to reach the alveoli. Predictive modelling was used to approximate external exposure concentrations. Consumer and environmental exposure were estimated conservatively and were not of concern. It was concluded based on the available weight-of-evidence that the production and application of the glass cleaner is safe for humans and the environment under intended use conditions.

  18. Evaluating the Control Banding Nanotool: a qualitative risk assessment method for controlling nanoparticle exposures

    NASA Astrophysics Data System (ADS)

    Zalk, David M.; Paik, Samuel Y.; Swuste, Paul

    2009-10-01

    Control banding (CB) strategies offer simplified processes for controlling worker exposures in the absence of firm toxicological and exposure information. The nanotechnology industry is an excellent candidate for applying such strategies with overwhelming uncertainties of work-related health risks posed by nanomaterials. A recent survey shows that a majority of nanomaterial producers are not performing a basic risk assessment of their product in use. The CB Nanotool, used internationally, was developed to conduct qualitative risk assessments to control nanoparticle exposures. Nanotoxicology experts have requested standardization of toxicological parameters to ensure better utility and consistency of research. Such standardization would fit well in the CB Nanotool's severity and probability risk matrix, therefore enhancing the protection of nanotechnology industry workers. This article further evaluates the CB Nanotool for structure, weighting of risk factors, and utility for exposure mitigation, and suggests improvements for the CB Nanotool and the research needed to bolster its effectiveness.

  19. Engineering the Intracellular Micro- and Nano-environment via Magnetic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Tseng, Peter

    Single cells, despite being the base unit of living organisms, possess a high degree of hierarchical structure and functional compartmentalization. This complexity exists for good reason: cells must respond efficiently and effectively to its surrounding environment by differentiating, moving, interacting, and more in order to survive or inhabit its role in the larger biological system. At the core of these responses is cellular decision-making. Cells process cues internally and externally from the environment and effect intracellular asymmetry in biochemistry and structure in order to carry out the proper biological responses. Functionalized magnetic particles have shown to be a powerful tool in interacting with biological matter, through either cell or biomolecule sorting, and the activation of biological processes. This dissertation reports on techniques utilizing manipulated magnetic nanoparticles (internalized by cells) to spatially and temporally localize intracellular cues, and examines the resulting asymmetry in biological processes generated by our methods. We first examine patterned micromagnetic elements as a simple strategy of rapidly manipulating magnetic nanoparticles throughout the intracellular space. Silicon or silicon dioxide substrates form the base for electroplated NiFe rods, which are repeated at varying size and pitch. A planarizing resin, initially SU-8, is used as the substrate layer for cellular adhesion. We demonstrate that through the manipulations of a simple external magnet, these micro-fabricated substrates can mediate rapid (under 2 s) and precise (submicron), reversible translation of magnetic nanoparticles through cellular space. Seeding cells on substrates composed of these elements allows simultaneous control of ensembles of nanoparticles over thousands of cells at a time. We believe such substrates could form the basis of magnetically based tools for the activation of biological matter. We further utilize these strategies to

  20. Practical framework for Bloom's based teaching and assessment of engineering outcomes

    NASA Astrophysics Data System (ADS)

    Mead, Patricia F.; Bennett, Mary M.

    2009-06-01

    ABET's outcomes-based assessment and evaluation requirements for engineering school accreditation has been a catalyst for curricular reform for engineering programs across the U.S. and around the world. Norfolk State University launched programs in Electronics and Optical Engineering in 2003. In 2007, Norfolk State became one of only six accredited Optical Engineering programs in the United States. In preparation for their first ABET evaluation in fall 2007, the faculty initiated an embedded-assessment program to insure continuous improvement toward the desired learning outcomes. The initial program design includes embedded assessments that have been generated using a practical framework for the creation of course activities based on Bloom's Learning Taxonomy. The framework includes specific performance criteria for each ABET-defined learning outcome. The embedded assessments are generated by individual faculty for courses that they are assigned to teach, and the performance criteria provide sufficient information to guide the faculty as they generate the embedded assignments. The assignments are typically administered through course exams, projects, electronic portfolio assignments, and other structured educational activities. The effectiveness of the assessment design is being evaluated through faculty surveys, faculty group discussions, and student performance. This paper outlines the assessment and evaluation plan, and the integrated processes that have been used to support the evaluation of learning outcomes using embedded assessment instruments.

  1. A place for arguing in engineering education: a study on students' assessments

    NASA Astrophysics Data System (ADS)

    Leite, Carlinda; Mouraz, Ana; Trindade, Rui; Martins Ferreira, José M.; Faustino, Ana; Villate, Jaime E.

    2011-12-01

    This paper focuses on the issue of how engineering programmes demand and/or promote argumentative reasoning, which is a subsequent aspect of curricular development. This was the main objective of the project on which this paper reports. This is to say that the focus is on assessment as a way to establish to what extent argumentative reasoning is demanded and mobilised in teaching and learning processes. This aim was achieved using a sample of assignments developed in courses in different Bologna undergraduate programmes at the Engineering School at the University of Porto, during the first semester of the academic year 2009/2010. Whereas problem solving in engineering constitutes a structural element in the curricular organisation of the engineering programmes and is strongly related to argumentative skills, it was possible to conclude that students demonstrate and explain extensively, but do not argue, possibly because their teachers do not invite them to do so in assessment situations.

  2. Interim report on the assessment of engineering issues for compact high-field ignition devices

    SciTech Connect

    Flanagan, C.A.

    1986-04-01

    The engineering issues addressed at the workshop included the overall configuration, layout, and assembly; limiter and first-wall energy removal; magnet system structure design; fabricability; repairability; and costs. In performing the assessment, the primary features and characteristics of each concept under study were reviewed as representative of this class of ignition device. The emphasis was to understand the key engineering areas of concern for this class of device and deliberately not attempt to define an optimum design or to choose a best approach. The assessment concluded that compact ignition tokamaks, as represented by the three concepts under study, are feasible. A number of critical engineering issues were identified, and all appear to have tractable solutions. The engineering issues appear quite challenging, and to obtain increased confidence in the apparent design solutions requires completion of the next level of design detail, complemented by appropriate development programs and testing.

  3. Effects of surface-engineered nanoparticle-based dispersants for marine oil spills on the model organism Artemia franciscana.

    PubMed

    Rodd, April L; Creighton, Megan A; Vaslet, Charles A; Rangel-Mendez, J Rene; Hurt, Robert H; Kane, Agnes B

    2014-06-03

    Fine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50-1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25-50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25-75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms.

  4. Controllable degradation kinetics of POSS nanoparticle-integrated poly(ε-caprolactone urea)urethane elastomers for tissue engineering applications

    PubMed Central

    Yildirimer, Lara; Buanz, Asma; Gaisford, Simon; Malins, Edward L.; Remzi Becer, C.; Moiemen, Naiem; Reynolds, Gary M.; Seifalian, Alexander M.

    2015-01-01

    Biodegradable elastomers are a popular choice for tissue engineering scaffolds, particularly in mechanically challenging settings (e.g. the skin). As the optimal rate of scaffold degradation depends on the tissue type to be regenerated, next-generation scaffolds must demonstrate tuneable degradation patterns. Previous investigations mainly focussed on the integration of more or less hydrolysable components to modulate degradation rates. In this study, however, the objective was to develop and synthesize a family of novel biodegradable polyurethanes (PUs) based on a poly(ε-caprolactone urea)urethane backbone integrating polyhedral oligomeric silsesquioxane (POSS-PCLU) with varying amounts of hard segments (24%, 28% and 33% (w/v)) in order to investigate the influence of hard segment chemistry on the degradation rate and profile. PUs lacking POSS nanoparticles served to prove the important function of POSS in maintaining the mechanical structures of the PU scaffolds before, during and after degradation. Mechanical testing of degraded samples revealed hard segment-dependent modulation of the materials’ viscoelastic properties, which was attributable to (i) degradation-induced changes in the PU crystallinity and (ii) either the presence or absence of POSS. In conclusion, this study presents a facile method of controlling degradation profiles of PU scaffolds used in tissue engineering applications. PMID:26463421

  5. Effects of Surface-Engineered Nanoparticle-Based Dispersants for Marine Oil Spills on the Model Organism Artemia franciscana

    PubMed Central

    2015-01-01

    Fine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50–1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25–50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25–75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms. PMID:24823274

  6. The impact of engineered cobalt, iron, nickel and silver nanoparticles on soil bacterial diversity under field conditions

    NASA Astrophysics Data System (ADS)

    Shah, Vishal; Collins, Daniel; Walker, Virginia K.; Shah, Shreya

    2014-01-01

    Our understanding of how engineered nanoparticles (NPs) migrate through soil and affect microbial communities is scarce. In the current study we examined how metal NPs, including those from the iron triad (iron, cobalt and nickel), moved through pots of soil maintained under winter field conditions for 50 days, when mesophilic bacteria may not be dividing. Based on total metal analysis, cobalt and nickel were localized in the top layer of soil, even after exposure to high precipitation and freeze-thaw cycles. In contrast, a bimodal distribution of silver was observed. Due to high endogenous levels of iron, the migration pattern of these NPs could not be determined. Pyrosequence analysis of the bacterial communities revealed that there was no significant engineered NP-mediated decline in microbial richness. However, analysis of individual genera showed that Sphingomonas and Lysobacter were represented by fewer sequences in horizons containing elevated metal levels whereas there was an increase in the numbers of Flavobacterium and Niastella. Collectively, the results indicate that along with the differential migration behavior of NPs in the soil matrix, their impact on soil bacterial diversity appears to be dependent on environmental parameters.